JP2000037937A - Method for aligning printing position, and printing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for aligning printing position which can simply and highly accurately perform aligning of the first printing and the second printing in a printing apparatus, e.g. printing between reciprocating scanning of a print head without troubling a user. SOLUTION: A plurality of patterns whose timings for starting of printing are shifted by a specified amt. to a reference dot are printed in a reciprocating scanning of a print head or a complementary printing by a plurality of heads. In addition, on each of a plurality of the patterns, optical characteristics are measured for a plurality of times by shifting the position to obtain a plurality of data and optical characteristics related to each of the patterns are obtd. from a plurality of these data and based on the optical characteristics, an adjusted value for the condition on dot forming position between the first and the second printings is obtd. In this instance, it is judged whether the pattern is formed under a condition where fluctuation on density is generated from a plurality of the data and such a pattern as this is extruded from the processing for obtaining the adjusted value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting a dot formation position in dot matrix recording and a printing apparatus using the method. The present invention relates to a method of adjusting a dot formation position applicable to print alignment between heads when printing is performed using a plurality of print heads, and a printing apparatus using the method.

[0002]

2. Description of the Related Art In recent years, relatively inexpensive OA devices such as personal computers and word processors have become widespread, and various recording devices for printing out information input by these devices, high-speed technology of the devices, and improvement of image quality have been developed. Technology is being developed rapidly. Among printing apparatuses, a serial printer using a dot matrix printing (printing) method has attracted attention as a printing apparatus (printing apparatus) that realizes high-speed or high-quality printing at low cost.
For such a printer, there is, for example, a bidirectional printing method as a technique for performing high-speed printing, and a multi-pass method as a technique for performing high-quality printing.

(Bidirectional printing method) As a high-speed technology, it has been considered to increase the number of print elements in a print head having a plurality of print elements and to improve the scanning speed of the print head. The reciprocating bidirectional print scanning is one effective method.

In a printing apparatus, since there is usually time for paper feeding and paper discharging, a simple proportional relationship is not obtained. However, bidirectional printing can obtain about twice the printing speed as compared with unidirectional printing.

For example, a print head having a print density of 360 dpi and arranging 64 ejection ports in a direction different from the print scanning (main scanning) direction (for example, a sub-scanning direction which is a feeding direction of a print medium) is used. When printing is performed with the print medium in portrait orientation, printing can be completed in about 60 print scans.
In one-way printing, all the print scans are performed only when moving in one direction from a predetermined scan start position, and non-print scans in the reverse direction for returning from the scan end position to the scan start position are performed. 60 round trips are performed. On the other hand, in bidirectional printing, printing is completed in about 30 reciprocal printing scans, and printing can be performed at a speed nearly twice as high. Therefore, it can be said that this is an effective method for improving printing speed. .

In order to perform such bidirectional printing, position detection means such as an encoder is used to match the dot formation positions on the forward path and the return path (for example, the landing positions of ink dots in an ink jet printing apparatus). The print timing is often controlled based on the detected position. However, configuring such a feedback control system causes an increase in the cost of the printing apparatus, and it has been considered that it is difficult to realize this with a relatively inexpensive printing apparatus.

(Multi-scan printing method) Next, a multi-scan printing method will be described as an example of a technique for improving image quality.

When printing is performed using a print head having a plurality of print elements, the quality of an image to be printed largely depends on the performance of the print head alone. For example, in the case of an ink jet print head, slight differences that occur in the print head manufacturing process, such as variations in the shape of the ink discharge ports and the elements that generate energy used for ink discharge, such as electrothermal transducers (discharge heaters), occur. This has an effect on the amount of ink to be ejected and the direction of the ejecting direction, which may cause unevenness in the density of a finally formed image and cause deterioration in image quality.

A specific example will be described with reference to FIGS. In FIG. 1A, a print head 201 includes eight nozzles (for the sake of simplicity, eight nozzles (in this specification, unless otherwise specified, a discharge port or a liquid path communicating therewith and energy used for ink discharge). The elements that generate the above are collectively referred to). Reference numeral 203 denotes ink ejected by the nozzle 202 as, for example, droplets. Normally, it is ideal that the ink is ejected from each ejection port in a substantially uniform ejection amount and in a uniform direction as shown in FIG. If such ejection is performed, ink dots of a uniform size land on the print medium as shown in FIG. 1B, and as a whole, as shown in FIG. Thus, a uniform image without density unevenness can be obtained.

However, in actuality, as described above, the print head 201 has a variation in each of the nozzles, and if the printing is performed in the same manner as described above, the print head 201 shown in FIG. As shown in FIG. 2, the size and direction of the ink droplets ejected from the respective nozzles vary, and land on the print medium as shown in FIG. 2B. According to this figure, there is a blank sheet portion whose area factor is less than 100% periodically in the head main scanning direction, or dots overlap more than necessary, or are seen in the center of this figure. Such white streaks have occurred. The collection of dots landed in such a state has a density distribution shown in FIG. 2C with respect to the nozzle arrangement direction, and as a result, these phenomena usually show the density unevenness as seen by human eyes. Is sensed as

Therefore, the following method has been devised as a measure against the density unevenness. The method will be described with reference to FIGS.

In this method, in order to complete printing in the same region as that shown in FIGS. 1 and 2, the print head 201 is connected to the print head 201 shown in FIGS.
Although scanning is performed three times as shown in (C), an area in units of four pixels, which is half of the eight pixels in the vertical direction in the figure, is completed in two passes. In this case, the eight nozzles of the print head are divided into groups of four nozzles in the upper half in the figure and four nozzles in the lower half, and the dots formed by one nozzle in one scan are used to convert image data into a predetermined image. It has been thinned out by about half according to the data array. At the time of the second scan, dots are embedded in the remaining half of the image data to complete a 4-pixel area. Such a printing method is hereinafter referred to as a multi-scan printing method.

When such a printing method is used, FIG.
Even if a print head 201 equal to the print head 201 is used, the influence on the print image due to the variation of each nozzle is reduced by half, and the printed image is as shown in FIG. The black and white stripes as shown in FIG. Therefore, the density unevenness is
As shown in FIG. 2C, it is considerably relaxed as compared with the case of FIG.

At the time of performing such printing, the image data is divided in the first scan and the second scan in such a manner as to fill each other according to a certain arrangement (mask). Usually, this image data arrangement (thinning pattern) is used. Is
As shown in FIG. 4, it is most common to use a pixel that is just a staggered lattice for each pixel in the vertical and horizontal directions. In a unit print area (here, in units of four pixels), printing is completed by the first scan in which dots are formed in a staggered manner and the second scan in which dots are formed in an inverted staggered manner. Usually, the movement amount (sub-scan amount) of the print medium between each scan is set to be constant, and FIGS.
In this case, the nozzles are evenly moved by four nozzles.

(Dot Alignment) Another example of a technique for improving image quality in a dot matrix printing method is a dot alignment technique for adjusting a dot landing position. Dot alignment is an adjustment method for adjusting the position at which dots are formed on a print medium by some means. Conventional dot alignment is generally performed as follows.

For example, in the landing position adjustment of the forward scan and the sub-scan in the reciprocal printing, the print timing is adjusted in each of the forward scan and the sub-scan so that the ruled line is changed while changing the relative print position condition in the reciprocal scan. Etc. are printed on a print medium. The user himself looks at it and selects the condition that seems to be the most aligned, that is, the condition that is printed without displacement of the ruled line, etc., and directly sets it by inputting it to the printing device by key operation or the like, Alternatively, the landing position condition is set in the printing apparatus via an application by operating the host computer.

In a printing apparatus having a plurality of heads, when printing is to be performed between a plurality of heads, ruled lines and the like are printed by the respective heads while changing relative printing position conditions among the plurality of heads. Print on top. As described above, the user selects the optimum condition for matching the print position, changes the relative print position condition, and sets the print position condition in the printing apparatus for each head by the same means as described above. Was.

[0018]

Here, a case will be described in which the landing positions of dots have shifted.

(Problems in performing image formation by bidirectional printing) The following problems are caused in bidirectional printing.

First, when printing a ruled line (vertical ruled line) in the direction perpendicular to the main scanning direction of the print head, the ruled line printed on the forward path and the ruled line printed on the return path are not aligned, and the ruled line is straight. Instead, a step occurs. Although this is so-called "ruled line deviation", it can be said that this is the most general image disturbance recognized by a general user. Since the ruled line is often formed in black, it has been generally recognized as a problem when forming a monochrome image, but the same phenomenon occurs in a color image.

Further, when multi-scan printing is used in combination for higher image quality, even if the landing positions do not match in bi-directional printing, the shift at the pixel level is not so noticeable as an effect of multi-scan printing. , The entire image looks uneven, and some users may recognize it as an unpleasant pattern. Although this is generally called texture, it occurs when a slight displacement of the landing position appears on the image in a specific cycle. It may be conspicuous in an image having a strong contrast such as a monochrome image, and may be conspicuous when performing halftone printing on a print medium capable of high density printing such as coated paper.

(Problems in performing image formation using a plurality of heads) In a printing apparatus having a plurality of heads,
Consider a problem in the case where the landing positions of dots have shifted between a plurality of heads.

When performing image printing, an image is often formed by combining several types of colors. The most common use is to use four colors obtained by adding black to the three primary colors of yellow, magenta, and cyan. General. When a plurality of print heads for printing these colors are used, if there is a deviation in the landing position between the print heads, a color shift occurs when different colors are printed on the same pixel depending on the amount of displacement. Would. For example, magenta and cyan are used to form a blue image, but when the dots of both colors overlap, they become blue, but where they do not, they do not become blue and each color appears independently. Color shift. Even if this occurs partially, it does not stand out, but if this phenomenon occurs continuously in the scanning direction, a band-like color shift of a specific width occurs, resulting in an uneven image. further,
If there is no deviation in the landing position of the dot in an area adjacent to the image of the same color, the sense of uniformity and coloring differs between the adjacent image areas, and the image becomes uncomfortable. Further, this color shift is not so noticeable on plain paper, but may be noticeable when using a print medium with good color development such as coated paper.

Further, when printing different colors on adjacent pixels, if there is a deviation in the landing position of the dot, a gap, that is, an area that is not covered by the ink occurs, and the ground of the print medium is directly visible. Sometimes. This phenomenon is often referred to as "white spots" since print media generally have a white background. This phenomenon is conspicuous in images with strong contrast, and when forming a black image with a chromatic color as the background, a white gap without ink exists between black and the chromatic color. May be more pronounced due to the high contrast between

(Problem) In order to suppress the above problems from occurring, it is effective to perform the above-described dot alignment. However, the user has to visually check the print result obtained by changing the landing position alignment condition, select the optimum landing position alignment condition, and perform an input operation. In some cases, a setting that is not optimal is made to force the user to determine the position. Therefore, it is particularly disadvantageous for a user unfamiliar with the operation.

Further, since the user must print an image for performing the landing position adjustment and make a necessary judgment after seeing the image, the user has to set the conditions. Will be hung,
This is not only unfavorable in realizing a device or system with good operability, but also disadvantageous in terms of time.

That is, an apparatus or system capable of printing a high-speed and high-quality image without causing the above-described problems in image formation and operability is provided by a feedback control means such as an encoder. It is strongly desirable that the landing position can be adjusted in an open loop without using the same and that it is realized at low cost.

Therefore, the present invention is to realize a low cost dot alignment method excellent in operability. Further, the present invention basically detects the optical characteristics of a printed image without compelling the user to make a judgment or adjustment, calculates an optimal dot alignment adjustment condition from the detection result, and adjusts the adjustment condition. The purpose is to enable automatic setting and to improve the adjustment accuracy.

[0029]

For this purpose, the present invention provides:
Processing for aligning print positions in the first and second prints for a printing apparatus that uses a print head and prints an image using first and second prints with different dot formation position conditions on a print medium. A pattern formed by the first print and the second print, wherein the pattern corresponds to a plurality of shift amounts of a relative print position between the first print and the second print. And each is formed,
A pattern forming step of forming, on the print head, a plurality of patterns each exhibiting optical characteristics in accordance with the plurality of shift amounts; and, for each of the plurality of formed patterns, varying the position to change the optical characteristics a plurality of times. A measurement step of measuring and obtaining a plurality of data; and obtaining the optical characteristics of each pattern from the plurality of data obtained for each of the plurality of patterns, based on the optical characteristics, the first print and the second print. An adjustment value obtaining step of obtaining an adjustment value of a dot formation position condition between two prints; and, from the plurality of data obtained for each of the plurality of patterns, the pattern is determined to be unsuitable for obtaining the adjustment value. It is determined that each of the plurality of patterns is formed, and formed in a state that is not suitable for obtaining the adjustment value For that pattern, characterized in that comprises a, a determination step of excluding from treatment with the adjustment value acquiring step.

Further, the present invention uses a print head,
What is claimed is: 1. A printing apparatus for printing an image by a first print and a second print having different dot formation position conditions on a print medium, wherein the print is a pattern formed by the first print and the second print. And a plurality of patterns formed on the print head corresponding to the plurality of shift amounts of the relative print position with respect to the second print, and respectively showing the optical characteristics corresponding to the plurality of shift amounts. Forming means, for each of the plurality of patterns formed, measuring means to obtain a plurality of data by measuring the optical characteristics a plurality of times at different positions, and the plurality of patterns obtained for each of the plurality of patterns Optical characteristics of each pattern are obtained from the data, and the first print and the second print are determined based on the optical characteristics. And an adjustment value obtaining means for obtaining an adjustment value of a dot formation position condition between the plurality of patterns, and the plurality of data obtained for each of the plurality of patterns, the pattern is formed in a state not suitable for obtaining the adjustment value. Determining that each of the plurality of patterns is determined to be performed, and for a pattern formed in a state that is not suitable for obtaining the adjustment value, a determination unit that excludes the pattern from the processing by the adjustment value obtaining unit. It is characterized by.

Further, the present invention provides a printing apparatus which prints an image by using a print head and performs first and second printing with different dot formation position conditions on a print medium, and prints the image with respect to the printing apparatus. A print system comprising: a host device that supplies data; and a pattern formed by the first print and the second print, wherein a pattern of a relative print position between the first print and the second print is provided. A pattern forming unit that is formed corresponding to the plurality of shift amounts, and that causes the print head to form a plurality of patterns that respectively indicate optical characteristics in accordance with the plurality of shift amounts, and each of the formed plurality of patterns; Measuring means for measuring a plurality of optical characteristics at different positions to obtain a plurality of data; and Adjusting the optical characteristics of each pattern from the plurality of data obtained for each of the above, and obtaining the adjustment value of the dot formation position condition between the first print and the second print based on the optical characteristics. Value acquisition means, from the plurality of data obtained for each of the plurality of patterns, it is determined for each of the plurality of patterns that the pattern is formed in a state not suitable for acquisition of the adjustment value, And determining means for excluding a pattern formed in a state unsuitable for obtaining the adjustment value from processing by the adjustment value obtaining means.

In the above-described printing position adjusting method, printing apparatus or printing system, the adjustment value obtaining step or means can calculate an average value of the plurality of data to obtain optical characteristics relating to the pattern.

[0033] The determining step or means may determine the presence of density unevenness occurring in the pattern from the plurality of data as a state unsuitable for obtaining the adjustment value.

The determining step or means may determine that when the difference between the maximum value and the minimum value of the plurality of data is larger than a predetermined value, the pattern is formed in a state not suitable for obtaining the adjustment value. It can be determined.

The pattern forming step or means forms a pattern more than the minimum required for the print position alignment, and determines whether there is a pattern formed in a state unsuitable for obtaining the adjustment value. The method may further include a step or means for subjecting the optical characteristics of another pattern to the process of obtaining the adjustment value.

If the exclusion does not provide a sufficient number of optical characteristics for the pattern to perform the adjustment value acquisition process, a step or means for accepting manual adjustment for print registration is provided. It can be further equipped.

Alternatively, when it is determined that the pattern is formed in a state that is not suitable for obtaining the adjustment value,
At least a step or means for causing the pattern to be re-formed and re-measured may be further provided.

[0038] The first print and the second print are respectively performed in forward scan and backward scan when printing is performed by reciprocally scanning the print head with respect to the print medium. Printing by a first print head and printing by a second print head, respectively,
And printing in a direction in which the second printhead is scanned relative to the print medium, and printing by the first printhead and the second printhead of the plurality of printheads, respectively. The method may include at least one of printing in a direction different from a direction in which the first and second print heads are scanned relative to the print medium.

The adjustment value acquisition step or means is based on the optical characteristic data obtained by the measurement step or means.
The adjustment value may be calculated by calculation using continuous values using linear approximation or polynomial approximation.

In the pattern forming step or means, the pattern can be formed at a pitch that is less than the pitch of the printing position that can be controlled by the printing apparatus.

In the pattern forming step or means, the dots of the first print and the dots of the second print are arranged, and the positional relationship between the dots is changed by changing the positional relationship between the dots in accordance with the plurality of shift amounts. By changing the ratio of covering the print medium, it is possible to form a plurality of patterns exhibiting optical characteristics according to the shift amount.

A plurality of printing elements for applying a printing agent to the printing medium are arranged in line at equal intervals in a direction different from the above-described direction, and a print head for performing the first printing, and a printing agent is applied to the printing medium. A plurality of print elements to be applied are arranged in line at equal intervals in a direction different from the above-mentioned direction, and a print head for performing the second print is aligned with a print apparatus that is used in parallel in the scanning direction. Can be performed.

The print head for performing the first print is a print head using a print material of at least one color tone, and the print head for performing the second print is a print head using at least one of a plurality of print materials of a color tone different from the color tone. May be used.

The print head may be a head that performs printing by discharging ink.

The head may include a heating element for generating thermal energy for causing film boiling of the ink as energy used for discharging the ink.

In this specification, "print"
(In the following, it may be referred to as "print") means not only the case where significant information such as characters and figures are formed, but also whether the information is significant or insignificant, and which is manifested so that humans can perceive it visually. Regardless of whether or not the image is formed, a case where an image, a pattern, a pattern, or the like is widely formed on a print medium or a case where the medium is processed is also referred to.

Here, the "print medium" is not limited to paper used in a general printing apparatus, but broadly refers to a material that can accept ink, such as a cloth, a plastic film, and a metal plate.

Further, “ink” is to be interpreted broadly as in the definition of “print” described above. When applied to a print medium, it forms an image, a pattern, a pattern, or processes the print medium. Liquid that can be provided to

[0049]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. Hereinafter, a case will be described in which the present invention is mainly applied to an inkjet printing apparatus and a printing system using the same.

1. Overview In a method (print position adjustment) and a printing apparatus for adjusting a dot formation position (ink landing position) according to an embodiment of the present invention, printing in the forward path and printing in the return path in bidirectional printing in which dot formation position adjustment is to be performed mutually. (Each corresponds to a first print and a second print), or each print (first print and second print) by a plurality (two) of print heads is performed at the same position on a print medium. . further,
The printing is performed under a plurality of conditions by changing the relative dot forming position alignment conditions between the first print and the second print. That is, a plurality of print patterns (patches) described later are formed by changing the relative position conditions of the first and second prints.

Then, the density is read using an optical sensor mounted on a main scanning member such as a carriage. That is, the optical sensor on the carriage is moved to a position corresponding to the patch, and the reflection optical density (or the intensity or reflectance of the reflected light) is measured. Then, the condition where the first and second print positions are most located is determined from the relative relationship between these values. That is, the approximate characteristic of the density with respect to the landing position condition is calculated from the relative relationship between the landing position condition and the density. An optimum landing position condition is obtained from the approximate characteristics. The image pattern to be printed at this time is set in consideration of the accuracy of the printing apparatus and the print head. In the first printing, a pattern having a width equal to or larger than the maximum deviation amount of the landing position accuracy predicted from the accuracy is printed on a printing medium.
In the second print, a pattern having the same width is printed under the alignment condition of each landing position. Thus, the landing position condition can be adjusted with an accuracy equal to or higher than the accuracy of the landing position alignment condition.

In the above-described measurement of the reflection optical density, density data is obtained for each of the plurality of patches, and density unevenness such that the dot alignment cannot be performed by adjusting the impact position on the patch based on the relative relationship between the data. It is determined whether or not there is, and the subsequent processing is changed.

That is, density data relating to a patch determined to have such density unevenness (hereinafter referred to as “density abnormality”) is excluded, and print position conditions are calculated using density data relating to other patches having no problem. I do. If a density abnormality occurs in a number of patches that are not sufficient for such calculation or the like, re-adjust the patch or the like to perform the adjustment again, or prompt the manual adjustment because adjustment is impossible. Is performed.

2. Example of Configuration of Printing Apparatus (2.1) Mechanical Configuration FIG. 5 is a perspective view showing an example of the configuration of a color inkjet printing apparatus suitable for implementing or applying the present invention. This shows a state where the inside of the device is exposed.

In the figure, reference numeral 1000 denotes a replaceable head cartridge, and reference numeral 2 denotes a carriage unit for detachably holding the ink jet cartridge. Reference numeral 3 denotes a holder for fixing the ink-jet cartridge 1000 to the carriage unit 2. When the ink-jet cartridge 1000 is mounted in the carriage unit 2 and the cartridge fixing lever 4 is operated, the ink-jet cartridge 1000 is moved in conjunction with the cartridge unit. 2 is pressed. In addition, at the same time as the positioning of the ink jet cartridge 1000 is performed by the pressure contact, a contact between a necessary signal transmission electrical contact provided on the carriage unit 2 and an electrical contact on the inkjet cartridge 1 side is performed. Reference numeral 5 denotes a flexible cable for transmitting an electric signal to the carriage unit 2. Although not shown in FIG. 5, a reflective optical sensor 30 is provided on the carriage.

Reference numeral 6 denotes a carriage motor serving as a drive source for reciprocating the carriage unit 2 in the main scanning direction.
Reference numeral 7 denotes a carriage belt that transmits the driving force to the carriage unit 2. Reference numeral 8 'denotes a guide shaft extending in the main scanning direction to support the carriage unit 2 and guide its movement. 9 is a carriage unit 2
Is a light-shielding plate provided near the carriage home position.
When the carriage unit 2 reaches the home position, the light blocking plate 10 blocks the optical axis of the photocoupler 9 so that the carriage home position is detected. 1
Reference numeral 2 denotes a home position unit including a cap member for capping the front surface of the inkjet head, suction means for suctioning the inside of the cap, and a recovery system such as a member for wiping the front surface of the head.

Reference numeral 13 denotes a discharge roller for discharging the print medium, which sandwiches the print medium in cooperation with a spur roller (not shown) and discharges the print medium out of the printing apparatus. A line feed unit 14 conveys a print medium by a predetermined amount in the sub-operation direction.

FIG. 6A is a perspective view showing the details of the ink jet cartridge 1000 used in this embodiment. Here, 15 is an ink tank containing black ink,
An ink tank 16 stores cyan, magenta, and yellow inks, which can be attached to and detached from the ink jet cartridge main body. 1
Reference numeral 7 denotes a connection port of each color ink stored in the ink tank 16 to the ink supply pipe 20 on the ink jet cartridge main body side, and reference numeral 18 denotes a connection port of black ink also stored in the ink tank 15, which is held by the ink jet cartridge main body by the connection. Ink can be supplied to the print head 1 which is in use. Reference numeral 19 denotes an electric contact unit, which can receive an electric signal from a control unit of the printing apparatus main body via a flexible cable in accordance with contact with the electric contact unit provided on the carriage unit 2.

In the present embodiment, a Bk ink ejection section in which nozzles for ejecting Bk ink are arranged, and Y, M
And a color ink ejection unit in which nozzle groups for ejecting C and C inks are arranged integrally and inline in correspondence with the Bk ejection port arrangement range.

FIG. 6B shows the head cartridge 100.
FIG. 2 is a schematic perspective view partially showing a main part structure of a print head unit 0 of FIG.

In FIG. 6B, a plurality of discharge ports 22 are provided at a predetermined pitch on a discharge port face 21 facing a print medium 8 with a predetermined gap (for example, about 0.5 to 2.0 mm). Are formed, and an electrothermal converter (heating resistor or the like) 25 for generating energy used for ink ejection is provided along a wall surface of each liquid path 24 communicating the common liquid chamber 23 and each discharge port 22. It is arranged. In this example, the head cartridge 1000 is mounted on the carriage 2 such that the ejection ports 22 are arranged in a direction intersecting the scanning direction of the carriage 2. In this manner, the corresponding electrothermal transducer (hereinafter, also referred to as “ejection heater”) 25 is driven (energized) based on the image signal or the ejection signal, and the ink in the liquid path 24 is film-boiled. The print head 1 ejects ink from the ejection port 22 by the pressure of the bubble generated in the print head 1.

In this embodiment, a configuration in which the nozzle group for discharging Bk ink and the nozzle group for discharging Y, M, and C inks are arranged side by side in one print head has been described. Instead, a print head having a nozzle group that discharges Bk ink and a print head having a nozzle group that discharges Y, M, and C inks may be independent, or a head cartridge may be independent. Is also good. Further, a head cartridge having a configuration in which the nozzle groups of each color are independent may be used. The combination of the print head and the head cartridge is not particularly limited.

FIG. 7 is a schematic view of the heater board HB of the head used in this embodiment. A temperature control (sub) heater 80d for controlling the temperature of the head, a discharge section array 80g provided with a discharge (main) heater 80c for discharging ink, and a drive element 80h are positioned as shown in FIG. In relation, they are formed on the same substrate. The heater board substrate is usually a chip of a Si wafer, on which heaters and required driving units are formed by the same semiconductor film forming process. By arranging each element on the same substrate in this manner, the head temperature can be efficiently detected and controlled, and the head can be made more compact and the manufacturing process can be simplified.

FIG. 6 shows the positional relationship of the outer peripheral wall cross section 80f of the top plate, which separates the area where the heater board of the Bk ink discharge section is filled with ink from the area where the ink is not filled. The discharge heater 80d side of the outer peripheral wall section 80f of the top plate functions as a common liquid chamber. In addition, a plurality of liquid paths are formed by a plurality of grooves formed on the discharge section row 80g of the outer peripheral wall cross section 80f of the top plate. The Y, M, and C color ink discharge units have substantially the same configuration.
By appropriately configuring the supply liquid chamber or top plate for each ink, separation or division is performed so that mixing of inks of different colors does not occur.

FIG. 8 is a schematic diagram for explaining the reflection type optical sensor 30 used in the apparatus of FIG.

As shown in FIG. 8, the reflection type optical sensor 30
Is attached to the carriage 2 as described above, and has a light emitting unit 31 and a light receiving unit 32. The light Iin 35 emitted from the light emitting unit 31 is reflected by the print medium 8, and the reflected light Iref 37 can be detected by the light receiving unit 32. The detection signal is transmitted to a control circuit formed on an electric board of the printing apparatus via a flexible cable (not shown), and is converted into a digital signal by the A / D converter. The position where the optical sensor 30 is attached to the carriage 2 is to prevent the attachment of droplets such as ink.
This is a position that does not pass through a portion through which the discharge port of the print head 1 passes during print scanning. Since a sensor having a relatively low resolution can be used as the sensor 30, a low-cost sensor is sufficient.

(2.2) Configuration of Control System Next, the configuration of a control system for executing print control of the above-described apparatus will be described.

FIG. 9 is a block diagram showing an example of the configuration of the control system. In the figure, a controller 100 is a main control unit, and is, for example, a microcomputer-type MP.
U101, a ROM 103 storing programs and required tables and other fixed data, and adjustment data obtained by dot alignment processing described later and used for print alignment at the time of actual printing (may be obtained for each mode described later. EEP for storing
Non-volatile memory 107 such as ROM, various data (the print signal and print data supplied to the head, etc.)
Is stored in a dynamic RAM 105 or the like for storing the information. The RAM 105 can also store the number of print dots, the number of times the ink print head has been replaced, and the like. A gate array 104 controls supply of print data to the print head 1 and also controls data transfer between the interface 112, the MPU 101, and the RAM 1105. The host device 110 is a supply source of image data (in addition to being a computer that creates and processes data such as images related to printing, it may be in the form of a reader unit for reading images). Image data, other commands, status signals, etc. are transmitted through the interface (I
/ F) 112 with the controller 100.

An operation unit 820 is a group of switches for receiving an instruction input by the operator, and includes a power switch 122, a switch 124 for instructing the start of printing, a recovery switch 126 for instructing activation of suction recovery, and a registration switch. In addition to the registration adjustment start switch 127 for starting, a registration adjustment value setting input unit 129 for manually inputting an adjustment value can be provided.

The sensor group 130 is a sensor group for detecting the state of the apparatus, and includes the above-mentioned reflection type optical sensor 30, a photocoupler 132 for detecting the home position, and an appropriate part for detecting the environmental temperature. It has a temperature sensor 134 and the like provided.

The head driver 150 is a driver for driving the discharge heater 25 of the print head 1 in accordance with print data and the like, and a timing setting section for appropriately setting a drive timing (discharge timing) for dot formation position alignment. Having. 151 is a driver for driving the main scanning motor 4, 162 is a motor used for conveying (sub-scanning) the print medium 8, and 160 is its driver.

FIG. 10 is a block diagram showing the components 104, 150, 1 shown in FIG.
3 is an example of a circuit showing details of the circuit. Gate array 104
Are a data latch 141, a segment (SEG) shift register 142, a multiplexer (MPX) 143, a common (COM) timing generation circuit 144, and a decoder 1.
45. The print head 1 has a diode matrix configuration, and a drive current flows through the discharge heaters (H1 to H64) where the common signal COM and the segment signal SEG coincide, whereby the ink is heated and discharged.

The decoder 145 decodes the timing generated by the common timing generation circuit 144 and selects one of the common signals COM1 to COM8.
The data latch 141 latches the print data read from the RAM 105 in units of 8 bits, and the multiplexer 143 stores the print data in accordance with the segment shift register 142 in accordance with the segment signals SEG1 to SEG8.
Output as The output from multiplexer 143 is
1-bit unit, 2-bit unit, or 8
Various changes such as all bits can be made according to the contents of the shift register 142.

The operation of the above control configuration will be described. When a print signal enters the interface 112, the print signal is converted into print data for printing between the gate array 104 and the MPU 101. Then, the motor drivers 151 and 160 are driven, and the print head is driven according to the print data sent to the head driver 150 to perform printing. Here, the case where the print head of 64 nozzles is driven has been described, but the drive control can be performed with a similar configuration with other numbers of nozzles.

Next, the flow of print data inside the printing apparatus will be described with reference to FIG. The print data sent from the host computer 110 is sent to a reception buffer RB inside the printing apparatus via the interface 112.
Is stored in The reception buffer RB has a capacity of several kilobytes to several tens kilobytes. The print data stored in the reception buffer RB is sent to the text buffer TB after the command analysis is performed.

In the text buffer TB, print data is held as an intermediate format for one line, and a process of adding a print position of each character, a type of modification, a size, a character (code), a font address, and the like is performed. Will be The capacity of the text buffer TB differs for each model, and a serial printer has a capacity for several lines, and a page printer has a capacity for one page. Further, the print data stored in the text buffer TB is expanded and stored in the print buffer PB in a binarized state, and a signal is sent to the print head as print data to perform printing.

In this embodiment, a signal is sent to the print head after multiplying the binarized data stored in the print buffer PB by a thinning mask pattern of a specific ratio. Therefore, it is possible to set the mask pattern after looking at the data stored in the print buffer PB. Depending on the type of the printing apparatus, there is also a type in which print data stored in the reception buffer RB is developed simultaneously with command analysis and written into the print buffer PB without having the text buffer TB.

FIG. 12 is a block diagram showing a configuration example of a data transfer circuit. Such a circuit can be provided as a part of the controller 100. In FIG.
A data register 1 is connected to a memory data bus, reads out print data stored in a print buffer in the memory and temporarily stores the print data, and 172 converts the data stored in the data register 171 into serial data. A serial-to-serial converter 173; an AND gate for masking serial data;
Reference numeral 174 denotes a counter for managing the number of data transfers.

A register 175 is connected to the MPU data bus, and stores a mask pattern. A selector 176 selects a digit position of the mask pattern.
Is a selector for selecting the row position of the mask pattern.

The data transfer circuit shown in FIG.
Print signal from the print head 1
, The 128-bit print data is serially transferred.
The print data stored in the print buffer PB in the memory is temporarily stored in the data register 171 and is converted into serial data by the parallel-serial converter 172. The converted serial data is AN
After being masked by the D gate 103, it is transferred to the print head 1. The transfer counter 174 counts the number of transfer bits and terminates the data transfer when it reaches 128.

The mask register 175 includes four mask registers A, B, C, and D, and stores a mask pattern written by the MPU. Each register is 4 vertical
A mask pattern of 4 bits × 4 bits is stored. The selector 176 selects mask pattern data corresponding to the digit position by using the value of the column counter 181 as a selection signal. The selector 177 has a transfer counter 174.
Is used as a selection signal to select mask pattern data corresponding to the row position. Selectors 176, 17
7 according to the mask pattern data selected by
The transfer data is masked using the ND gate 173.

In this example, a description has been given of the configuration of four mask registers. However, this may be another number of mask registers. In this example, the masked transfer data is supplied directly to the print head 1, but may be temporarily stored in the print buffer.

3. First Example of Dot Alignment (Print Position Alignment) Next, a description will be given of a form of print alignment which is a basic of the present embodiment.

(3.1) Basic Mode of Dot Alignment FIGS. 13A to 13C are schematic diagrams showing examples of print patterns in print position alignment in bidirectional printing.

In FIGS. 13A to 13C, white dots 700 are dots formed on a print medium in forward scanning (first print) and hatched dots 710.
Indicates dots formed in the backward scan (second print). In FIGS. 13A to 13C, the presence or absence of dot hatching is given for explanation. However, in this embodiment, each dot is a dot formed by ink ejected from the same print head, and the color of the dot is It does not correspond to the density.

FIG. 13A shows dots when printing is performed in a state where the print positions are aligned in the forward scan and the backward scan, and FIG. 13B shows a state in which the print positions are slightly shifted.
(C) shows dots when printing is performed with the print position further shifted. In addition, these FIG.
As is clear from (A) to (C), in this embodiment, complementary dot formation is performed in each reciprocating scan. That is, in the forward scan, dots in the odd-numbered columns are formed, and in the backward scan, dots in the even-numbered columns are formed. Therefore, in the case of FIG. 13A in which the dots of each reciprocation have a distance of about one dot diameter from each other, the print positions are matched.

This print pattern is designed so that the density of the entire print portion decreases as the print position shifts. That is, the area factor is approximately 100% within the range of the patch as the print pattern in FIG. As shown in FIGS. 13B and 13C, as the print position shifts, the overlap between the forward scan dots (white dots) and the backward scan dots (hatched dots) increases, and an unprinted area. ,
That is, the area not covered by the dots also expands.
As a result, the area factor is reduced, so that on average the overall density is reduced.

In this embodiment, the print position is shifted by shifting the print timing. This is possible even if it is shifted on the print data.

Although FIGS. 13A to 13C show one dot unit in the scanning direction, an appropriate unit is set according to the accuracy of registration (print position alignment) or the accuracy of registration detection. can do.
FIGS. 14A to 14C show the case of a unit of 4 dots.
(A) shows a state in which the print positions are aligned, (B) shows a state of a slight shift, and (C) shows a state of dots when printing is performed with a further shift.

The intention of these patterns is to reduce the area factor while the print positions of the reciprocation shift from each other. This is because the density of the printed portion strongly depends on the change of the area factor. That is, although the density increases due to the overlapping of the dots, the increase in the unprinted area has a greater effect on the average density of the entire printed portion.

FIG. 15A to FIG. 13A to FIG.
14C schematically shows the relationship between the amount of shift in the print position and the change in the reflection optical density in the print patterns shown in FIGS.

In FIG. 15, the vertical axis represents the reflection optical density (O
D value), and the horizontal axis is the amount of displacement of print position (μm)
It is. The incident light Iin35 and the reflected light Iref37 in FIG.
Is used, the reflectance R = Iref / Iin, and the transmittance T = 1−R. The optical density includes a reflection optical density using the reflectance R and a transmission optical density using the transmittance T. In this specification, the reflection optical density is used. Is abbreviated.

Assuming that the reflection optical density is d, there is a relationship of R = 10 ^−d . Since the area factor is 100% when the amount of displacement of the print position is 0, the reflectance R
Is the smallest. That is, the reflection optical density d becomes maximum. Even if the printing position is relatively displaced in any of the + and-directions, the reflection optical density d decreases.

FIG. 16 is a schematic flowchart of the print registration process.

As shown in FIG. 16, first, a plurality of predetermined print patterns are printed (step S1). For example, a patch element (white dot group in FIG. 14A) in which four dot formation areas formed in the forward path (first print) and a blank area of four dots are repeated, and a return path (second dot group). A patch element (FIG. 14) in which four dot formation areas formed by printing and a blank area for four dots are repeated.
(A) is a pattern formed by superimposing a dot group with hatching (A) with a shift of one dot within a range of ± 4 dots. This pattern is formed by shifting print timing or shifting on print data. Can be formed.

Next, these print patterns are scanned by the optical sensor 30 (step S2). An appropriate print position parameter is obtained based on the optical characteristics obtained from the scanned data (step S3). For example, FIG.
8 (described later), it can be obtained from a curve obtained by polynomial approximation using the least squares method, using a point having the highest reflection optical density or the like. In any case, the change of the drive timing is set by the print position parameter for this point P (step S4).

FIG. 17 shows a state in which the print pattern shown in FIGS. 13A to 13C or FIGS. 14A to 14C is printed on the print medium 8. FIG. In the present embodiment,
9 with different relative displacement between forward scan and backward scan
The corresponding patterns 61 to 69 are printed. Each printed pattern is also called a patch, for example, a patch 61,
62 and the like. The print position parameters corresponding to the patches 61 to 69 are represented as (a) to (i), respectively. This 9
As for the patterns 61 to 69, the print start timings of the forward scan and the backward scan are fixed in the forward scan. On the other hand, for the start timing of the backward scanning, printing is performed at a total of nine timings, that is, the currently set start timing, four earlier timings, and four later timings. Processing described below can be added to the processing procedure of FIG. 16 as appropriate.

The print medium 8 and the carriage 2 are moved so that the optical sensor 30 mounted on the carriage 2 comes to a position corresponding to the patch 61 or the like as a print pattern printed in this manner. The optical characteristics of each of the patches 61 and the like are measured a plurality of times in a state where is stationary. In the case of this example, the reflection optical density or the transmission optical density is used as the optical characteristic. However, an optical reflectance, a reflected light intensity, or the like may be used. As described above, by performing measurement while the carriage 2 is stationary, the influence of noise due to driving of the carriage 2 can be avoided. Further, by increasing the size of the measurement spot of the optical sensor 30 with respect to the dot diameter by appropriately setting the distance between the sensor 30 and the print medium 8, for example, local optical characteristics (eg, By averaging the variation of the reflection optical density, the reflection optical density of the patch 61 or the like can be measured with high accuracy.

As a configuration for making the measurement spot of the optical sensor 30 relatively wide, it is desirable to use a sensor having a resolution lower than the print resolution of the pattern, that is, a sensor having a measurement spot diameter larger than the dot diameter. In the example, a sensor having a relatively high resolution, that is, a sensor having a small measurement spot diameter, is measured over a plurality of points on the patch, and the average of the densities thus obtained is used as the measured density. That is, in order to avoid the influence of measurement variations, the reflection optical density of the same patch is measured at a plurality of positions, and the average value is adopted.

Note that the measurement can be performed while moving the carriage 2 to reduce the time. In this case, it is desirable to increase the number of samplings and perform averaging or some kind of arithmetic processing in order to avoid measurement variations due to electric noise due to motor driving.

(3.2) Density Unevenness Even if dot formation is performed under uniform driving conditions for some reason, the landing position of ink is shifted between the first and second prints, resulting in uneven density (abnormal density). May occur.

FIG. 18 is an explanatory view of such density unevenness, and it is assumed that the head is driven under uniform conditions in both the states (A) and (B). Here, (A) shows a state where the landing position is not shifted between the first and second prints, and a uniform density is obtained. However, (B) shows a state in which the intervals between the rows of dots (hatched dots) formed by the second printing are shifted in a direction in which the rows are narrowed, and the density is uneven even though the head is driven under uniform conditions. Has occurred.

The causes of such uneven density include the following.

FIG. 19 shows that the carriage scanning speed fluctuates between the first print (a) by "head 1" and the second print (b) by "head 2", and data is printed at the same position. This is a case where even if an attempt is made to make a difference in the interval between the landing positions.

FIG. 20 shows that after the first print (a) by the “head 1”, local expansion or floating (cockling) occurs in the medium 8, and the second print (b) by the “head 2” This is a case where the relative landing position interval changes.

(3.3) Mode of Acquisition and Use of Density Data in First Example If the above occurs in the process of forming each patch as shown in FIG. 17, the measured density changes, and the accuracy of print position alignment is changed. May be lowered.

Therefore, in this example, the density is measured at a plurality of levels within an area of one patch formed under the same dot formation position condition at a multi-valued level, and the above problem occurs due to the relative relationship between the data. It is determined whether or not there is any data, and basically the dot alignment processing is performed excluding data relating to the patch in which the density unevenness has occurred.

FIG. 21 shows an example of a procedure for determining the occurrence of density measurement or density unevenness, which can be positioned as the sensor scan processing step S2 in the dot alignment processing procedure of FIG.

That is, after forming a plurality of patches as shown in FIG. 17 by the first and second prints under a plurality of print position conditions in step S1 of FIG. 16, each of the patches 61 to 69 has a plurality of points. A density measurement is performed (step S21).

FIG. 22 shows one patch (for example, patch 6
1) is enlarged, and a cross mark is a measurement point or a center of a measurement spot by the optical sensor 30. In FIG. 22, 12 data are acquired,
The difference between the largest one and the smallest one is calculated, and whether the above-mentioned problem of the density unevenness has occurred depends on whether the value is larger than a predetermined threshold value (for example, 30 levels) or not. Is determined.

Then, patches 61 to 69 as shown in FIG.
It is determined whether or not there is a patch for which the occurrence of density unevenness has been determined (step S23). If there is no problem, an average value of 12 data is calculated for each patch, and the average value is calculated for the patch. Data (step S2
7), the nine data (average density data of each of the patches 61 to 69) are subjected to the print position parameter acquisition processing in step S3 in FIG.

FIG. 23 shows an example in which the nine data thus obtained are plotted in a relationship between a printing position (dot shifting) condition (horizontal axis) and a density value (vertical axis). Further, the result obtained by approximating this by a quartic equation by the least squares method is shown by a dotted line. From this equation, the position (P) having the highest density is determined so that the optimum print position condition is selected.

Next, when it is determined that there is a patch for which the occurrence of density unevenness is determined, it is determined whether or not the number is greater than a predetermined number (step S24). The same processing as described above is performed on data excluding data on patches having uneven density.

FIGS. 24 and 25 show the result of the polynomial approximation by the least squares method in that case.
As described above, if the density unevenness has occurred in the number of patches that have no problem in the required calculation, the processing can be performed on the remaining patches in the same manner as described above.

On the other hand, if there is a patch in which the density unevenness has occurred more than a predetermined number, the user is notified of the unsuccessful automatic dot alignment processing by display or the like, and the same as the conventional method using a ruled line pattern or the like. It is possible to prompt manual adjustment (step S100) as described later.

According to the above example, variations occur in the measurement results due to the uneven density occurring in the patch pattern.
It is possible to prevent the inconvenience that the accuracy of the print registration is reduced. In particular, if the number of patches in which density unevenness has occurred is equal to or less than a predetermined number, by proceeding with the remaining patches, the time required for a series of alignment processing such as starting manual adjustment more than necessary is not increased. In addition, the print alignment processing can be performed with high accuracy.

(3.4) Modification of Data Processing In the method of this example, the calculation of print position alignment is performed by excluding data relating to patches determined to have density unevenness under predetermined conditions. Is what you do. This method is not limited to the above-described least-squares method polynomial approximation.

For example, as shown in FIG. 26, the data of the measured reflection optical density is obtained, the point having the highest reflection optical density is obtained, and each straight line passing through the data on both sides of the point having the highest reflection optical density is determined by the least square method or the like. This example can be applied to the case where the intersection P of these straight lines is obtained by using the following equation. That is, the data of (a), (b), (c), and (e),
In the case of performing print position alignment using the data of (f) and (g), for example, any one of (a), (b) and (c), or (e) and (f) , (G), the required calculation can be performed without any one of them.

According to the method as shown in FIG. 23 or FIG. 26, the pitch is finer than the print alignment condition such as the print pitch used for printing the print pattern 61 or the print alignment condition at a higher resolution. Can be selected.

The method of calculating the print alignment condition is not limited to this method. Calculate numerical values from these multiple multi-value density data and information on the print alignment conditions used for pattern printing, and perform print alignment with an accuracy equal to or higher than the discrete values of the print alignment conditions used for pattern printing. Calculating the condition is also one of the intentions of the present invention.

In the above example, one patch has 12
The measured data is obtained, the difference between the largest one and the smallest one is calculated, and if the value is larger than a predetermined threshold value (for example, 30 levels), density unevenness occurs in the patch. Not use the data related to the patch. However, the purpose is to acquire a plurality of data from patches with the same print position condition, and to determine whether or not density unevenness has occurred in the patch based on the relative relationship, and the method is not limited to the above-described method. . Needless to say, the number of measurement points and the measurement positions are also examples.

For example, an averaging process is performed among three adjacent data from the plurality of measured data, and the maximum value and the minimum value among the data are obtained, and the average value is compared with the threshold value for determination. You may. Further, the variance of the plurality of measured data may be calculated, and the determination may be made based on the calculated variance.
Further, for the plurality of measured data, the position at which the data was obtained may be approximated to a polynomial by the least squares method, and the presence or absence of density unevenness may be determined based on the magnitude of the coefficient of the first or square term. . In addition, if there is no problem, by excluding data indicating an extreme value among a plurality of measurement data due to localized occurrence of density unevenness, an average value is calculated for the remaining data, and the density data of the patch is also calculated. Good.

The same applies to the second and third examples described later.

[0124] 4. Second Example of Dot Alignment (Print Position Alignment) In a second example of the embodiment of the present invention, at least a patch in which the occurrence of density unevenness has been determined is printed at another position on the print medium 8 and measured. Even when the density unevenness phenomenon occurs due to some factor, it is possible to perform the print position alignment processing with high accuracy.

This is because when the print position is likely to be displaced on a very small portion of the print medium due to mechanical factors, for example, in a device that performs one-way printing, the scanning speed of the carriage is increased when the carriage is accelerated. This is effective when density fluctuation occurs in a part where a pattern (patch) starts to be formed.

To explain this example with reference to FIG. 27, patches (here, eight patches indicated by reference numerals 61 to 68) are formed, and the optical sensor 30 acquires density data in the same manner as in the first example. The density unevenness is determined. Then, it is assumed that it is determined that the patterns 61 to 63 indicated by oblique lines in the patch group of FIG.

In this case, as shown in FIG.
The patches 61 to 68 are formed again while avoiding the area where the density unevenness occurs. Then, by re-measuring the print position, the print registration process can be performed with high accuracy.

According to this method, since all the patch patterns are formed again, that is, the density of the patches formed under relatively close conditions is measured and the alignment is performed, so that the process can be performed with lower variation. There is.

As another method, as shown by (c) in the figure, by changing the order of forming patches, the data of the patches 65 to 68 obtained in the first forming (a) and the new forming The dot alignment processing may be performed using the data of the patches 61 to 64 obtained in (c). This method has an advantage that processing can be performed even with a print medium having a narrow width in the main scanning direction as compared with the method shown in FIG. As a modified example of this method, it is conceivable to reverse the order of forming patches ((d) in the figure).

In the second example described above, at least a patch whose density has been determined to be uneven is formed at another position on the print medium 8 and measured. This makes it possible to perform print alignment processing with high accuracy. To reduce the processing time, instead of forming and measuring all patches as described above, the occurrence of density unevenness occurs. It is also possible to perform the formation and measurement again only of the sample that has been made.

In any case, compared to the first example, the data for calculating the print registration position is not lost, so that the risk of lowering the calculation accuracy can be reduced.

[0132] 5. Third Example of Dot Alignment (Print Position Alignment) In a third example of the embodiment of the present invention, a patch having a position condition other than the minimum pattern required for print position adjustment, for example, a pattern of a plurality of times for a plurality of position conditions is also used. When it is determined that there is density unevenness, high-precision processing is performed by performing recovery using such data.

Referring to FIG. 28, this example will be described. In the illustrated example, a pattern is formed twice. First, density measurement and density unevenness determination are performed for one set of patch groups on the left side. If there is no density unevenness, print position adjustment conditions are calculated using the data. On the other hand, if there is density unevenness, density measurement and density unevenness determination are performed for one set of patch groups on the right side.

As a result, if there is no density unevenness, the printing position adjustment condition is calculated using the data. If it is determined that there is also density unevenness in one set on the right side, the same as in the first example is performed. Then, the user can be notified of the failure of the automatic dot alignment processing by display or the like, thereby prompting manual adjustment using a ruled line pattern or the like.

In the method of the present embodiment, as compared with the second example, it is possible to secure an area in the sub-scanning direction of the print medium for forming a new patch and to save the time required for the area. Further, compared to the first example, data for calculating the print registration position is not lost, so that the risk of lowering the calculation accuracy can be reduced.

In this example, the right set is measured only when it is determined that there is uneven density. However, if the time required for the measurement is sufficiently short, the right and left sets are measured from the beginning. You may keep it.

In the third example, a patch having a position condition other than the minimum pattern required for print position alignment is also formed, and when it is determined that there is uneven density, recovery is performed using those data. This is to perform high-precision processing in such a manner, and is not limited to forming two sets of patch groups. For example, three or more sets may be formed, or only a patch formed in a portion which is considered to have a high possibility of occurrence of density unevenness may be formed in another position a plurality of times.

Further, the present invention is not limited to forming a plurality of patches having the same print position condition, and using the data of the patches formed under similar conditions, the data of the pattern determined to have uneven density can be obtained. You may cover it.

6. Dot Alignment Between Multiple Heads (6.1) Horizontal Dot Alignment In the above example, the relative shift amount or adjustment amount with respect to reciprocating path printing with the same head (ejection unit) was obtained. The range can be appropriately determined according to the apparatus configuration, the print mode of the apparatus, and the like.
For example, FIG. 1 using a plurality of print heads (ejection units)
In addition to the above-described bidirectional printing, the printing apparatus as described above performs dot alignment in main scanning direction printing between a plurality of heads. In a printing apparatus using only one head, the above-described bidirectional printing is performed. May be performed. If one head can eject inks of different colors (colors and densities) or can obtain different ejection amounts, dot alignment is performed for each color tone or each ejection amount. You may.

In the dot alignment processing between a plurality of heads, for example, for two heads, in the above example, the patch elements formed for the forward path and the return path are formed by each head, and the density of the patch printed by these is measured. The adjustment value can be obtained with. This 2
The example of the relationship between three heads can be similarly applied to the relationship between three or more heads. For example, for three heads, the print positions of the first head and the second head may be adjusted, and then the positions of the first head and the third head may be adjusted (this is a vertical position). The same applies to dot alignment).

However, the apparatus used in the embodiment is a B type in which nozzles for discharging Bk ink are arranged as shown in FIG.
A head is used in which a k ink ejection unit and a color ink ejection unit in which nozzle groups for ejecting Y, M, and C inks are arranged integrally and inline corresponding to the Bk ejection port arrangement range, respectively. Things. Therefore, in particular, in the vertical dot alignment process between a plurality of heads (ejection units), if the print position between Bk and, for example, C is adjusted, it is manufactured in the same process as the ejection orifice group of C ink, and is integrated and inline. The print position alignment of the nozzle groups of the M and Y inks with respect to the Bk ejection portion is also substantially performed, that is, the dot alignment process between a plurality of heads (ejection portions) is completed.

Accordingly, the red LED is used as the light-emitting portion particularly in the dot alignment processing between a plurality of heads (ejection units), while the Bk and C inks having sufficient absorption characteristics for the red light are used for the measurement patch. Is formed and print alignment is sufficient.

However, depending on the characteristics of the LED used,
By determining the color used for dot alignment,
It can also correspond to each color. Conversely, LEDs can be selected according to the color of the pattern. For example, by mounting a blue LED, a green LED, and the like in addition to red, dot alignment can be performed for Bk for each color (C, M, Y). Further, in a case where each color ejection unit (head) is configured separately and used in juxtaposition with a printing apparatus, it is preferable to perform print registration for all colors. The necessary adjustment processing may be performed for each of them.

Similar adjustments can be made not only in the main scanning direction but also in the sub-scanning direction (vertical direction). For example, the ink ejection openings of each print head (ejection unit) are provided over a range wider than the maximum width (band width) in the sub-scanning direction of an image that can be formed by one scan, and the range of the ejection openings to be used is set. By adopting a configuration in which the print position is shifted, the print position can be corrected in the unit of the discharge port interval. That is, as a result of shifting the correspondence between the data to be output (image data or the like) and the ink ejection ports, the output data itself can be shifted. However, the vertical adjustment is performed at such image data positions, and the vertical print alignment accuracy depends on the resolution of the print head and the control resolution of the feed direction of the print medium. In some cases, adjustments can be made using these.

In this embodiment, the horizontal dot alignment can be performed not only in the forward scan printing between the heads but also in the backward scan printing. This is because, when the dot alignment of bidirectional printing is adjusted by one head, a landing position shift may occur even if the adjustment value is used in other print heads. This is because if the print heads have different ink discharge directions or different discharge speeds, the state of bidirectional printing differs for each print head. In response to such a phenomenon, when only one adjustment value for bidirectional printing can be set, dot alignment is performed with one print head based on bidirectional printing. Next, the horizontal dot alignment is performed for each scan print using the print head, which has been the reference for bidirectional printing, also as the reference in the horizontal direction. Thereby, it is possible to suppress the occurrence of the displacement of the landing position in the bidirectional or lateral direction due to the characteristics of the print head.

When a plurality of adjustment values for bidirectional printing can be set, dot alignment for bidirectional printing is performed for each print head, and dot alignment is performed only in one horizontal direction. Even when the characteristics of the head are different, the landing position can be adjusted.

To shift the landing position during the dot alignment processing or the actual printing operation using the result, the following can be applied.

The bidirectional printing is performed by, for example, the discharge start position control using an interval equal to the interval at which the trigger signal of the carriage motor 6 is generated. in this case,
80 for the gate array 140 by software, for example.
An nsec interval can be set. However, it is only necessary to have the required resolution, and 2880 dpi (8.8 μm)
m) is sufficient accuracy.

In the horizontal direction of printing using a plurality of heads, image data is controlled at intervals of 720 dpi. As for the displacement within one pixel, for example, in a mode in which the nozzle group is divided into several blocks and driven in a time-division manner, 720
The control is performed by changing the order of selecting blocks for dpi driving, and controlling the shift of one or more pixels by shifting the image data to be printed among a plurality of heads.

(6.2) Print Position Adjustment in the Vertical Direction Next, print position adjustment between a plurality of heads in a direction perpendicular to the carriage scanning direction will be described.

In the printing apparatus according to the present embodiment, in order to correct the print position in the direction (sub-scanning direction) perpendicular to the carriage scanning direction, the image formed by the ink ejection openings of the print head in one scan is corrected. The print position can be corrected in the unit of the discharge port interval by disposing the discharge ports to be used in a range wider than the width (band width) in the sub-scanning direction. That is, as a result of shifting the correspondence between the data to be output (image data or the like) and the ink ejection ports, the output data itself can be shifted.

In the above-described print registration for bidirectional printing and print registration in the main scanning direction of a plurality of heads, a print pattern that maximizes the measured reflection optical density when the print positions are matched is used. Here, a print pattern is used in which the reflection optical density becomes minimum when the print position is correct, and the reflection optical density increases as the print position shifts.

In the case of so-called paper feed direction (vertical direction) alignment, a pattern in which the density is maximized in the presence of the print position, the print position is shifted, and the density is reduced can be used as described above. For example, the alignment can be performed by paying attention to dots formed by the respective ejections that are adjacent to each other in the paper feeding direction between the two heads.

FIGS. 29A to 29C schematically show print patterns used in the print position alignment process in the vertical direction.

FIGS. 29A to 29C, white dots 8
Reference numeral 2 denotes dots printed by the first print head, and hatched dots 84 indicate dots printed by the second print head. FIG. 29A shows a state in which the print positions are aligned.
The white dots are not visible because the types of dots overlap. (B) shows a dot printed when the print position is slightly shifted, and (C) shows a dot state when the print position is further shifted. As can be seen from these figures, as the printing position shifts, the area factor increases, and the overall average reflection optical density increases.

By displacing the ejection pattern used for printing one of the two print heads related to the print position adjustment, the print pattern described above is changed to a plurality of patterns while changing the print position adjustment conditions for this shift. Print And
The reflected optical density of the printed patch is measured.

FIG. 30 schematically shows an example of the measured reflection optical density. Here, five patterns are exemplified.

In FIG. 30, the vertical axis indicates the reflection optical density, and the horizontal axis indicates the amount of displacement of the print outlet. Here, among the measured values of the reflection optical density, the printing condition ((c) in FIG. 30) indicating the lowest reflection optical density is selected as the condition for the best printing position.

In the vertical direction of printing using a plurality of heads, for example, the image data is controlled at intervals of 360 dpi, and the image data to be printed is shifted between the plurality of heads.

7. Other Examples of Patch Patterns In the above, square or rectangular patterns (patches) separated from each other are printed for a plurality of print alignment conditions as shown in FIG. 17, but the configuration is not limited to this. It suffices if there is an area in which density measurement can be performed for each print alignment condition. For example, all of the plurality of print patterns (such as the patches 61) in FIG. 17 may be connected. By doing so, the area of the print pattern can be reduced.

However, when this pattern is printed on the print medium 8 by the ink jet printing apparatus,
Depending on the type of the print medium 8, if the ink is ejected over a certain area over a certain amount, the print medium 8 expands to cause cockling as described above, and the landing accuracy of ink droplets discharged from the print head is reduced. There are cases. The print pattern as shown in FIG. 17 has an advantage that the phenomenon can be avoided as much as possible.

In the print patterns shown in FIGS. 13A to 13C, the condition in which the reflection optical density changes most sensitively to the shift of the print position is that the print position exists between the reciprocal scans. FIG. 13A shows that the area factor becomes almost 100%. That is, it is desirable that the area where the pattern is printed is almost covered with the dots.

However, for a pattern in which the reflection optical density decreases due to a shift in the printing position,
It is not always necessary to satisfy such conditions. However, preferably, the distance between the dots printed in each reciprocating scan with the print position between the reciprocating scans was,
It is sufficient that the distance range overlaps from the distance at which the dots touch each other to about the radius of each dot. If you do this,
The reflection optical density changes sensitively according to the deviation from the state where the print position is located. Such a distance relationship between dots is realized depending on the dot pitch and the size of the formed dots, as described below, and in the case of pattern printing when the formed dots are relatively small. In some cases, the distance relationship is artificially formed.

The print patterns for the forward scan and the backward scan do not necessarily have to be lined up vertically.

FIGS. 31A to 31C show a print pattern in which dots printed in the forward scan and dots printed in the backward scan are intertwined with each other. FIG. (B) is a slightly shifted state,
(C) is a schematic diagram showing dots when printed in a further shifted state. The present invention can be applied to such a pattern.

FIGS. 32A to 32C show patterns in which dots are formed obliquely. FIG. 32A shows a state in which the print positions are aligned, FIG. 32B shows a state in which the dots are slightly shifted, and FIG. FIG. 9 is a schematic diagram showing dots when printed in a further shifted state. The present invention can be applied to such a pattern.

FIGS. 33 (A) to 33 (C) show patterns in which a plurality of dot rows for each reciprocating scan to be shifted in print position are shown. FIG. 33 (A) shows a state in which print positions are matched, and FIG. () Is a schematic diagram showing dots when printed with a slight shift, and (C) is a diagram showing dots when printed with a further shift.

In the case of performing print position adjustment by changing print position alignment conditions such as print start timing in a wide range, the dot rows for each reciprocating scan (first and second prints) to be shifted are designated. A pattern having a plurality of columns is effective, and FIG. 14 adopted in the above processing is one example thereof. FIG.
In the print pattern of (C), the set of dot rows to be shifted is a one-way reciprocating dot row, so as the print position shift increases, it overlaps with other sets of dot rows, and more than that. This is because the reflection optical density does not decrease even when the print position shift amount increases. On the other hand, in the case of the patterns as shown in FIGS. 14 and 33, the distance of the printing position shift until the dot row overlaps with the other set of dot rows in each of the reciprocal scanning is shown in FIGS.
The print pattern can be made longer than that of the print pattern described above, whereby the print alignment condition can be changed in a wide range.

FIGS. 34A to 34C show a print pattern in which predetermined dots are thinned out for each dot row, and FIG.
(B) is a schematic diagram showing dots when printed with a slight shift, and (C) is a diagram showing dots when printed with a further shift. The present invention can be applied to such a pattern. In this pattern, the density of the dots formed on the print medium 8 itself is large, and when the patterns shown in FIGS. 13A to 13C are printed, the overall density becomes too large. This is effective when the density difference cannot be measured according to the deviation. That is, FIG.
If the dots are thinned and reduced as in (A) to (C), the unprinted area on the print medium 8 increases, and the density of the entire printed patch can be reduced.

On the other hand, when the print density is too low, the printing may be performed such that the printing is performed twice at the same position to form the dots, or only a part of the printing is performed twice.

The characteristic that the print position shifts with respect to the print pattern and the reflection optical density is reduced include, as described above, the dots printed in the forward scan and the dots printed in the backward scan are in contact with each other in the carriage scanning direction. Condition is required. However, such conditions need not necessarily be satisfied in the entire pattern, and the reflection density may be reduced as the print positions of the forward scan and the backward scan shift as a whole pattern.

8. Processing Addable to Dot Alignment Sequence The processing procedure in FIG. 16 includes the above-described dot alignment processing in bidirectional printing for other colors and the main scanning direction and / or the backward scanning direction between a plurality of heads (ejection units). In addition to the dot alignment process between two or more heads,
If necessary, the following processing can be added.

(8.1) Recovery Operation This is a series of operations to improve or maintain the ink discharge state of the print head, such as suction, wiping, and preliminary discharge, before executing automatic dot alignment. A recovery operation is performed.

As an operation timing, when there is an instruction to execute automatic dot alignment, a recovery operation is performed before the instruction is executed. This makes it possible to print a pattern for print registration in a state where the ejection state of the print head is stable, and it is possible to set a more reliable correction condition for print registration.

The recovery operation is not limited to a series of operations including suction, wiping, and preliminary discharge, but may be preliminary discharge or only preliminary discharge and wiping. In this case, it is preferable that the preliminary discharge is set so that the number of preliminary discharges is larger than that of the preliminary discharge at the time of printing. Further, the combination of the number of times of suction, wiping, and preliminary ejection and the operation order are not particularly limited.

Further, it may be determined whether or not to execute the suction recovery before the automatic dot alignment control according to the elapsed time from the previous suction recovery. In this case, first, immediately before performing the automatic dot alignment, it is determined whether a predetermined time has elapsed from the previous suction operation. Then, if the suction operation has been performed within a predetermined time, the automatic dot alignment registration is performed. On the other hand, if the suction recovery operation has not been performed within the predetermined time, the automatic dot alignment can be performed after performing a series of recovery operations including the suction recovery.

In addition, it is determined whether or not the print head has ejected a predetermined number of inks or more from the previous suction recovery. If a predetermined number of inks has been ejected, the recovery operation is performed. After execution, automatic dot alignment may be performed, and furthermore, both the elapsed time and the number of ink ejections may be used as a judgment material, and if either of them reaches a predetermined value, suction recovery is performed. May be.

By doing so, it is possible to prevent excessive suction recovery, thereby contributing to saving of ink consumption and reduction of the amount of ink discharged to the waste ink processing unit. In addition, the recovery operation before the automatic dot alignment can be efficiently performed.

Further, the recovery condition is made variable in accordance with the elapsed time from the previous suction recovery or the number of ink ejections. For example, when the elapsed time is short, only the preliminary ejection and the wiping are performed without performing the suction operation. If the elapsed time is long, the recovery condition may be changed such that the suction recovery is further inserted.

As described above, the recovery operation can be performed. However, it is not always necessary to use a configuration for performing the recovery operation.
There is no need to perform a recovery operation within the automatic dot alignment process. It is more preferable to carry out the automatic dot alignment process while ensuring high reliability.

(8.2) Sensor Calibration As in each of the above-described dot alignment examples, the patch is irradiated with light from the light emitting side of the optical sensor 30, and a predetermined process is performed based on the relative value of the reflected light output. In order to determine a proper printing alignment condition, a good output difference cannot be obtained unless an optimum amount of light is applied and an optimum electric signal is applied to the light receiving side. In order to obtain a sufficient output difference (output difference between patterns when the print position is changed to the minimum in the actual print alignment pattern), calibration of the sensor (light emitting unit side and / or light receiving unit side) itself is performed. It is desirable to carry out. This is due to variations inherent in density sensors (optical sensors), sensor mounting tolerances in printing devices, light and humidity in the operating environment, air conditions (fog, smoke)
This is preferable in correcting the differences in atmosphere such as the above, the aging of the sensor itself, the effect of the output drop due to heat generation, and the effect of the output drop due to mist or paper dust adhering to the sensor.

Therefore, in the calibration of the light-emitting portion (such as an LED) of the optical sensor 30, the optical sensor 30 is desirably used in a linear region so that a predetermined range can be obtained as the output characteristic of the optical sensor. For example, the input power can be PWM-controlled to perform such calibration. Specifically, the applied current is PWM-controlled to control the amount of current applied at 5% intervals, for example, from 100% duty full energization to 5% duty energization, thereby obtaining an optimal current duty. The LED of the optical sensor 30 can be driven.

The calibration of the light emitting section will be briefly described. The maximum rated value of the electric signal applied to the light emitting side is set to 100%, and the maximum rated value is sequentially changed from 0% to 100% in the minimum unit in which the light emission amount changes. The measured output characteristics are measured in accordance with a predetermined image pattern for calibration in which the reflectance is changed. If the light amount is too weak, the reflected light amount is too small between the outputs of the patterns having different reflectivities, and the output difference becomes poor. Conversely, if the light emission amount is too strong, the output of the pattern having a different reflectance will be large in a pattern with a reflectance close to a white background, and will almost differ from the output of the white background when the detection ability on the light receiving side is exceeded. Cannot be seen. Therefore, if such a pattern of the reflectance area exists in the actual print registration pattern, a good output difference cannot be obtained. In view of this, in view of the fact that a sufficient output difference is obtained in the reflectance region of the pattern used for print positioning, a drive current that can ensure a good S / N ratio is selected.

The drive signal on the light emission side is modulated by the processing of the MPU 101 in the printer, and the modulation unit amount can be performed in the minimum unit in which the light emission amount changes.

The same applies to the calibration on the light receiving side, and it is possible to determine the optimum electric signal application condition for measuring the reflectance of the pattern for print position alignment by the method described above. Modulation of the drive signal on the light receiving side is performed by processing of the MPU 101 in the printer, and the modulation unit amount can be performed in the minimum unit in which the light emission amount changes.

Next, the measurement object (calibration pattern) used for sensor calibration is composed of a color sensitive to the sensor emission wavelength. It may be a single color or a combination of a plurality of colors as long as the reflectance does not change depending on the position in the predetermined area.

When a sensor calibration pattern with a changed reflectance is used, each pattern may be an independent patch, or a partial pattern with a changed reflectance may be continuous. .

In the sensor calibration, the electric signal may be roughly changed to perform the coarse adjustment, and then the fine adjustment may be performed by slightly changing the electric signal. Good.

In the sensor calibration, the measurement may be performed while changing the applied electric signal in the carriage main scanning process, or the measurement may be performed while the carriage is stopped and then changed. Further, the sensor calibration may be performed within one scan,
It may be performed by a plurality of scans.

(8.3) Confirmation Pattern After performing the dot alignment, the set landing is performed in order to confirm whether the control has been performed reliably or to enable the user to recognize the result of the dot alignment. The confirmation pattern can be printed using the position condition. Normally, ruled line patterns are easy to recognize, so ruled line printing is performed in each mode such as bidirectional printing and between a plurality of heads, and at each printing speed. Thereby, the user can recognize the result of the implemented dot alignment at a glance.

(8.4) Manual Adjustment In this embodiment, the density is detected using an optical sensor, and then the automatic dot alignment processing is performed. However, other dot alignment processes can be performed in case the optical sensor does not operate favorably or the automatic dot alignment described above is unsuccessful. That is, manual adjustment can be performed. The conditions for shifting to such manual adjustment are as described above in step S1 of FIG.
00, the following cases can be adopted.

First, calibration can be performed when using the optical sensor. If the data obtained at that time is clearly out of the usable range, a calibration error is determined and the dot alignment operation is performed. To stop. The status of the state is communicated to the host computer to indicate that there is an error via the application. Further, a message is displayed prompting the user to perform manual adjustment, and the execution is prompted. Alternatively, when a calibration error is detected, the dot alignment operation may be stopped, and printing may be performed on the fed print medium to prompt the user to perform manual adjustment.

The optical sensor may malfunction depending on the incidence of external light. Therefore, when the reflected light becomes extremely strong during the dot alignment, it is determined that there is disturbance light, and the dot alignment is stopped. Then, similarly to the calibration error, the status of the state is communicated to the host computer, and the fact that the error has occurred is displayed via the application. Further, a message is displayed prompting the user to perform manual adjustment, and the execution is prompted. Alternatively, when a calibration error is detected, the dot alignment operation may be stopped, and printing may be performed on the fed print medium to prompt execution of manual adjustment.

However, if the sensor error is transient such as accidental disturbance light incident, the dot alignment processing is performed again after a while or by informing the user to adjust the conditions. Can be started. Further, if an error occurs during execution of one of various print registration processes corresponding to a mode and the like described later, the process can be stopped and another print registration process can be performed.

Next, the specific contents of the manual adjustment (step S100 and the like in the processing procedure of FIG. 21) performed when the automatic dot alignment sequence cannot be performed as described above will be described.

In the manual adjustment, a ruled line pattern of one dot is used. A ruled line pattern as a reference in the first print is printed on a print medium, and a plurality of ruled lines with different relative position conditions (ruled lines with different shift amounts) are printed in a second print. The user looks at the printed matter and determines which condition is the most optimal. Therefore, for easy determination, a one-dot ruled line is used so that the position where the landing position is most suitable can be seen at the actual dot position.

The manual adjustment can include a coarse adjustment and a fine adjustment performed thereafter.

In the coarse adjustment of the manual adjustment, a ruled line pattern according to the tolerance range of the landing position of the printing apparatus and the print head is used. For example, the coarse adjustment when the tolerance accuracy is ± 4 dots is as shown in FIG.

In FIG. 35A, it is assumed that the reference line and the shift line are printed by the printing means to be adjusted. In addition, when the shift amount is exactly 0, the landing position is illustrated as being matched.

Looking at such a pattern, the user determines which condition is most suitable for the landing position (registration is correct), and inputs the adjustment value to the printing apparatus main body, or It is input from the device (such as a menu of a printer driver) or stored in the main body.

Further, in order to perform the adjustment with higher accuracy, a pattern as shown in FIG. 35B is printed and fine adjustment is performed.

In FIG. 35B, the adjustment is made in units of 0.5 dot, but the selection can be made according to the adjustment capability (adjustment resolution, adjustment accuracy) of the main body. Then, similarly to the coarse adjustment, the user determines which condition is most suitable for the landing position (registration is correct) and performs the adjustment. The fine adjustment for performing the adjustment with higher accuracy can be performed on the assumption that the landing position is matched to some extent in the coarse adjustment. Without the premise of the coarse adjustment, the reference line and the shift line may be printed at completely different positions. This is a principle in the case where dot alignment is performed using such a simple ruled line, and only one point is an adjustment value.

(8.5) Dot Alignment Process According to Mode, etc. The execution range of the dot alignment can be appropriately determined according to the apparatus configuration, the print mode of the apparatus, and the like. For example, in a printing apparatus as shown in FIG. 1 using a plurality of print heads (ejection units), in addition to the above-described bidirectional printing, dot alignment in the main scanning direction between a plurality of heads is performed, and one printing is performed. In a printing apparatus using only a head, dot alignment for bidirectional printing as described above may be performed. If one head can eject inks of different colors (colors and densities) or can obtain different ejection amounts, dot alignment is performed for each color tone or each ejection amount. May be.

When the amount of ink to be ejected is different, the adjustment value of the dot alignment may be different in terms of the main scanning speed, the ejection speed, and the ejection angle. This is because when such dot alignment is performed, the landing position may be different for other ejection amounts even if the adjustment value is used.

No. If the ejection speed differs depending on the color of the ink used, dot alignment may be performed for each color, and an optimal landing position adjustment value may be provided for each color.

Further, such adjustment may be made collectively for all the modes of the printing apparatus when the processing procedure is started, or may be made only for the mode designated according to the selection by the user or the like. You may.

The activation of the adjustment process is performed by operating a start switch or the like provided on the printer main body or by an instruction through an application of the host device.
For example, considering the aging of each part of the printing device and the head,
By using a management means such as a timer, the adjustment process can be started or prompted when the adjustment has not been performed for a long time. The head cartridge 100
Even when 0 is exchanged, the adjustment processing can be started or prompted.

9. Others In each of the above embodiments, an example of an ink jet printing apparatus that forms an image by discharging ink from a print head onto a print medium has been described, but the present invention is not limited to this configuration. Any printing apparatus is effective as long as it prints by forming dots by relatively moving the print head and the print medium.

However, in particular, when the ink jet printing system is used, among them, a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for ink ejection is provided. The present invention provides an excellent effect in a print head and a printing apparatus of a type in which a change in the state of ink is caused by thermal energy. This is because such a method can achieve higher density and higher definition of the print.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an electrothermal converter arranged corresponding to the liquid path. Applying at least one drive signal corresponding to the printing information and providing a rapid temperature rise exceeding nucleate boiling, causing the electrothermal transducer to generate thermal energy, causing film boiling on the heat-acting surface of the printhead. This is effective because bubbles can be formed in the liquid (ink) corresponding to this drive signal on a one-to-one basis. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in U.S. Pat. No. 4,313,124 relating to the rate of temperature rise of the heat acting surface are adopted, more excellent printing can be performed.

As the configuration of the print head, a combination configuration of a discharge port, a liquid path, and an electrothermal converter (a linear liquid flow path or a right-angled liquid flow path) as disclosed in each of the above-mentioned specifications.
In addition, the present invention also includes a configuration using U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600 which disclose a configuration in which a heat acting portion is arranged in a bending region. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, printing can be performed reliably and efficiently regardless of the form of the print head.

Further, the present invention can be effectively applied to a full line type print head having a length corresponding to the maximum width of a print medium that can be printed by a printing apparatus. Such a print head may have a configuration that satisfies the length by combining a plurality of print heads, or a configuration as a single integrally formed print head.

In addition, even in the case of the serial type as described above, a print head fixed to the apparatus main body, or an electric connection to the apparatus main body or ink from the apparatus main body by being mounted on the apparatus main body. The present invention is also effective when a replaceable chip-type print head that can be supplied or a cartridge-type print head in which an ink tank is provided integrally with the print head itself is used.

It is preferable to add a discharge recovery means for the print head, preliminary auxiliary means, and the like as the configuration of the printing apparatus of the present invention since the effects of the present invention can be further stabilized. If you list these specifically,
Pre-heating means for heating using a capping means, a cleaning means, a pressure or suction means, an electrothermal converter or another heating element or a combination thereof for the print head, Pre-discharge means for performing another discharge can be given.

Further, the type and number of print heads to be mounted are, for example, one for one color ink.
In addition to those provided with only a plurality of inks, a plurality of inks may be provided corresponding to a plurality of inks having different print colors and densities. That is, for example, the print mode of the printing apparatus is not limited to the print mode of only the mainstream color such as black, but may be any of a print head integrally formed or a combination of a plurality of print heads. The present invention is also very effective for an apparatus provided with at least one of the full-color print modes using mixed colors.

[0216] In addition, in the above-described embodiment of the present invention, the ink is described as a liquid.
An ink that solidifies at room temperature or below and softens or liquefies at room temperature may be used, or the ink jet method controls the viscosity of the ink by adjusting the temperature of the ink itself within the range of 30 ° C to 70 ° C. In general, the temperature is controlled so that is within the stable ejection range, and therefore, a liquid in which the ink is in a liquid state when the use print signal is applied may be used. In addition, in order to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink, the ink is solidified in a standing state and heated. May be used. In any case, the application of heat energy causes the ink to be liquefied by the application of heat energy according to the print signal and the liquid ink to be ejected, or to start solidifying when it reaches the print medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In such a case, the ink is held in a state in which the ink is held as a liquid or a solid in the concave portion or through hole of the porous sheet as described in JP-A-54-56847 or JP-A-60-71260. Alternatively, it may be configured to face the electrothermal converter. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, the form of the ink jet printing apparatus of the present invention is not only used as an image output terminal of an information processing apparatus such as a computer, but also has a copying apparatus combined with a reader or the like, and further has a transmission / reception function. A facsimile apparatus may be used.

[0218]

According to the present invention, the first print and the second print of each of the forward pass and the return pass in which the mutual dot formation positions are to be adjusted, or the first print of each of the plurality of print heads. In the second printing, the optimum adjustment value of the landing position of the print dot can be obtained with high accuracy. Accordingly, it is possible to provide a printing method and a printing apparatus capable of performing bidirectional printing in which the landing positions are not shifted, or printing using a plurality of print heads.

Further, it is possible to realize an apparatus or a system capable of printing a high-speed and high-quality image at low cost without causing a problem in image formation and a problem in operability.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining the principle of dot matrix printing.

FIG. 2 is an explanatory diagram for explaining a problem of density unevenness that may occur in dot matrix printing.

FIG. 3 is an explanatory diagram for explaining the principle of multi-scan printing for preventing the occurrence of density unevenness described in FIG. 2;

FIGS. 4A to 4C are explanatory diagrams for explaining staggered / inverted staggered printing employed in multi-scan printing.

FIG. 5 is a perspective view illustrating a schematic configuration example of an inkjet printing apparatus according to an embodiment of the present invention.

FIGS. 6A and 6B are perspective views showing a configuration example of a head cartridge shown in FIG. 5 and a configuration example of a discharge unit thereof, respectively.

FIG. 7 is a perspective view illustrating a configuration example of a heater board used in the ejection unit of FIG. 6;

FIG. 8 is a schematic diagram for explaining an optical sensor used in the device of FIG.

FIG. 9 is a block diagram illustrating a schematic configuration of a control circuit in the inkjet printing apparatus according to one embodiment of the present invention.

FIG. 10 is a block diagram showing an example of an electrical configuration of a gate array or a heater board in FIG. 9;

FIG. 11 is a schematic diagram for explaining a flow of print data from the host device to the inside of the printing device.

FIG. 12 is a block diagram illustrating a configuration example of a data transfer circuit.

FIGS. 13A and 13B are schematic diagrams showing a print pattern that can be used for the dot alignment process of the present invention, wherein FIG. 13A shows a state where the print positions are aligned, and FIG. FIG. 7C is a schematic diagram showing dots when printed in a further shifted state.

FIGS. 14A and 14B are schematic diagrams illustrating a pattern for print alignment that can be used in the dot alignment processing of the present invention, in which FIG. (B) is a schematic view showing dots when printed in a slightly shifted state, and (C) is a schematic view showing dots when printed in a further shifted state.

FIG. 15 is a diagram showing the relationship between the amount of shift of the print position in the print pattern and the reflection optical density.

16 is a flowchart illustrating an example of a control procedure for executing a dot alignment process using the relationship in FIG.

FIG. 17 is a schematic diagram showing a state in which a print pattern that can be formed in the dot alignment process of the present invention is printed on a print medium.

FIGS. 18A and 18B are explanatory views of a state of density unevenness that can occur in a pudding pattern under the same print position condition.

FIGS. 19A and 19B are diagrams for explaining one cause of the occurrence of the uneven density shown in FIG. 18;

20 (a) and (b) are diagrams for explaining another cause of the occurrence of the density unevenness shown in FIG. 18;

FIG. 21 is a flowchart illustrating an example of a sensor scan procedure that can be positioned in the procedure of FIG. 6;

FIG. 22 is a diagram for explaining a measurement method for one patch by a sensor.

FIG. 23 is an explanatory diagram of print registration condition determination executed when there is no measurement data excluded by the processing of FIG. 21;

24 is an explanatory diagram of print registration condition determination executed when there is measurement data to be excluded by the processing of FIG. 21;

FIG. 25 is an explanatory diagram of a print alignment condition determination executed when there is measurement data to be excluded by the processing of FIG. 21;

FIG. 26 is a diagram for explaining another method of determining print alignment conditions.

FIG. 27 is a diagram illustrating a second example of the dot alignment process.

FIG. 28 is a diagram illustrating a third example of the dot alignment process.

FIG. 29 is a schematic diagram for explaining characteristics of a preferred example of a print pattern that can be used for print position alignment in a sub-scanning direction between a plurality of heads, depending on a distance between dots;
(A) is a schematic view showing a dot in which the print position is aligned, (B) is a slightly shifted state, and (C) is a schematic view showing a dot when printed in a further shifted state.

FIG. 30 is a diagram showing a relationship between a shift amount of a print outlet and a reflection optical density in FIG. 29;

FIGS. 31A and 31B are schematic diagrams illustrating another example of a pattern for print alignment that can be used in the dot alignment processing of the present invention. FIG. B) is in a slightly shifted state,
(C) is a schematic diagram showing dots when printed in a further shifted state.

32A and 32B are schematic diagrams illustrating still another example of a pattern for print alignment that can be used in the dot alignment processing of the present invention, wherein FIG. (B) is a schematic diagram showing dots when printed with a slight shift, and (C) is a diagram showing dots when printed with a further shift.

FIG. 33 is a schematic diagram for explaining still another example of a pattern for print alignment that can be used in the dot alignment processing of the present invention. FIG. (B) is a schematic diagram showing dots when printed with a slight shift, and (C) is a diagram showing dots when printed with a further shift.

34A and 34B are schematic diagrams illustrating still another example of a pattern for print alignment that can be used in the dot alignment processing of the present invention. FIG. (B) is a schematic diagram showing dots when printed with a slight shift, and (C) is a diagram showing dots when printed with a further shift.

FIGS. 35A and 35B are explanatory diagrams for explaining coarse adjustment and fine adjustment of dot alignment manually, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Print head 2 Carriage unit 3 Carriage unit holder 5 Flexible cable 6 Carriage motor 7 Carriage belt 8 Print medium 8 'Guide shaft 9 Photocoupler 10 Light shielding plate 12 Home position unit including recovery system 13 Discharge roller 14 Line feed unit 15 Black ink Storage ink tank 16 Color ink storage tank 19 Electrical contact section 21 Discharge port surface 22 Discharge port 23 Common liquid chamber 24 Liquid path 25 Electrothermal transducer 30 Reflective optical sensor 100 Controller 101 MPU 103 ROM 104 Gate array 105 RAM 107 Non-volatile Memory 110 Host device 112 Interface 122 Power switch 124 Print start instruction switch 126 Recovery switch 127 Registration Registration adjustment start switch 129 Registration adjustment value setting input unit 130 Sensor group 150 Head driver 162 Transport (sub-scanning) motor 820 Operation unit 1000 Head cartridge

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B41J 3/12 C (72) Inventor Kiichiro Takahashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tsutomu Iwasaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Minoru Teshigawara 3-30-2, Shimomaruko 3-chome, Ota-ku, Tokyo Canon Inc. (72 ) Inventor Tomoyuki Tsukuma 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2C056 EA06 EA07 EA08 EA11 EA12 EB04 EB27 EB42 EC04 EC24 EC25 EC28 EC37 EC54 EC57 EC59 EC60 EC75 EC77 EC80 EE02 FA03 FA11 FB01 FB03 FB04 HA58 KC22 2C061 AP03 AP04 AP10 AQ05 AR01 AS11 KK03 KK04 KK22 KK24 KK25 KK27 KK28 KK33 2C062 AA04 AA08 AA14 AA22 AA24 AA32 AB06 2C480 CA17 CA 30 CA55 CB45 EC02 EC05 EC11 EC13 EC15

Claims (45)

[Claims] 1. A printing apparatus that prints an image by a first and a second print using a print head and different dot formation position conditions on a print medium, in the first and second prints. A print position alignment method for performing a process for performing the first print and the second print, wherein a plurality of relative print positions of the first print and the second print are provided. A pattern forming step of forming a plurality of patterns on the print head, each of which is formed in accordance with the amount of misalignment, and which exhibits optical characteristics in accordance with the plurality of amounts of misalignment, respectively. Measuring the optical characteristics a plurality of times at different positions to obtain a plurality of data; From the plurality of data obtained for each, optical characteristics of each pattern are obtained, and an adjustment value of a dot formation position condition between the first print and the second print is obtained based on the optical characteristics. An adjustment value acquisition step, and from the plurality of data obtained for each of the plurality of patterns, determine that each of the plurality of patterns is formed in a state that is not suitable for acquiring the adjustment value. And a determining step of excluding a pattern formed in a state unsuitable for obtaining the adjustment value from the processing in the adjustment value obtaining step. 2. The print position alignment method according to claim 1, wherein in the adjustment value obtaining step, an average value of the plurality of data is calculated to obtain an optical characteristic of the pattern. 3. The method according to claim 1, wherein the determining step determines the presence of density unevenness occurring in the pattern from the plurality of data, as a state unsuitable for obtaining the adjustment value. Print alignment method described. 4. The method according to claim 1, wherein the determining step determines that the pattern is not suitable for obtaining the adjustment value when a difference between a maximum value and a minimum value of the plurality of data is greater than a predetermined value. The method according to claim 1, wherein the determination is performed. 5. The method according to claim 1, wherein the pattern forming step forms a pattern more than a minimum necessary for the print registration, and determines whether there is a pattern formed in a state unsuitable for obtaining the adjustment value. 5. The print position alignment method according to claim 1, further comprising a step of providing an optical characteristic relating to another pattern to a process of acquiring the adjustment value. 6. If the exclusion does not provide a sufficient number of optical characteristics of the pattern to perform the adjustment value acquisition process, accepting a manual adjustment for print registration. 6. The method according to claim 1, further comprising the step of: 7. The method according to claim 1, further comprising, when it is determined that the pattern is formed in a state that is not suitable for obtaining the adjustment value, at least performing a re-formation and a re-measurement of the pattern. The print registration method according to any one of claims 1 to 4. 8. The printing according to claim 1, wherein the first print and the second print are respectively performed in forward scan and backward scan when the print head is reciprocally scanned with respect to the print medium to perform printing. A first printhead and a second printhead, respectively, wherein the first and second printheads are printed in a direction relative to the print medium, and a plurality of prints. A direction different from a direction in which the first and second printheads are respectively scanned by the first and second printheads relative to the print medium, wherein the first and second printheads are respectively printed by the first printhead and the second printhead; Including at least one of the prints relating to The print registration method according to claim 1. 9. The adjustment value obtaining step includes calculating the adjustment value by using continuous values from the optical characteristic data obtained in the measurement step, using linear approximation or polynomial approximation. 9. The print registration method according to claim 1, wherein: 10. The printing method according to claim 1, wherein in the pattern forming step, the pattern is formed at a pitch that is smaller than a pitch of a printing position that can be controlled by a printing apparatus. Alignment method. 11. The method according to claim 11, wherein in the pattern forming step, the first
By disposing dots by printing and dots by the second printing, and changing the positional relationship between the dots in accordance with the plurality of shift amounts to change the ratio of the dots covering the print medium, the shift amount 11. The print position alignment method according to claim 1, wherein a plurality of patterns exhibiting optical characteristics according to the following are formed. 12. A print head for performing the first print in which a plurality of printing elements for applying a printing agent to the print medium are arranged at equal intervals in a line in a direction different from the above-mentioned direction, and a printing agent for applying the printing agent to the printing medium. A plurality of print elements to be applied to the medium are arranged in line at equal intervals in a direction different from the above-described direction, and a print head for performing the second print is printed in a printing apparatus using the print head in parallel in the scanning direction. 12. The print registration method according to claim 1, wherein registration is performed. 13. A print head for performing the first print uses a print agent using a print agent of at least one color, and a print head for performing the second print uses a plurality of print agents of at least one color different from the color tone. 13. The method according to claim 12, wherein the print head is a print head. 14. The print positioning method according to claim 1, wherein the print head is a head that performs printing by discharging ink. 15. The print positioning apparatus according to claim 14, wherein the head has a heating element that generates thermal energy that causes film boiling of the ink as energy used for discharging the ink. Method. 16. A printing apparatus that prints an image by using a print head and performing first and second printing with different dot formation position conditions on a printing medium, wherein the printing apparatus is formed by the first printing and the second printing. A plurality of patterns, each of which is formed corresponding to a plurality of shift amounts of a relative print position between the first print and the second print, and which shows optical characteristics respectively corresponding to the plurality of shift amounts. Pattern forming means for forming the pattern on the print head, for each of the plurality of patterns formed, measuring means to obtain a plurality of data by measuring the optical characteristics a plurality of times at different positions, From the plurality of data obtained for each of the patterns, optical characteristics of each pattern are obtained, and Adjustment value obtaining means for obtaining an adjustment value of a dot formation position condition between the first print and the second print based on the plurality of data obtained for each of the plurality of patterns; It is determined for each of the plurality of patterns that the pattern is formed in a state that is not suitable for the, from the processing in the adjustment value acquisition means for the pattern that is formed in a state that is not suitable for the acquisition of the adjustment value A printing apparatus comprising: a determination unit for excluding the printing apparatus. 17. The printing apparatus according to claim 16, wherein the adjustment value acquisition unit calculates an average value of the plurality of data to obtain an optical characteristic of the pattern. 18. The method according to claim 16, wherein the determination unit determines the presence of density unevenness occurring in the pattern from the plurality of data as a state unsuitable for acquiring the adjustment value. The printing device according to the above. 19. The method according to claim 19, wherein when the difference between the maximum value and the minimum value of the plurality of data is larger than a predetermined value, the pattern is formed in a state not suitable for obtaining the adjustment value. The method according to claim 16, wherein the determination is made.
9. The printing apparatus according to any one of 8. 20. The image forming apparatus according to claim 1, wherein the pattern forming unit forms more patterns than the minimum required for the print registration, and determines whether there is a pattern formed in a state unsuitable for obtaining the adjustment value. 20. The printing apparatus according to claim 16, further comprising: a unit for providing an optical characteristic of another pattern to a process of acquiring the adjustment value. 21. A means for accepting manual adjustment for print alignment when the exclusion does not provide a sufficient number of optical characteristics for the pattern to perform the adjustment value acquisition process. The printing apparatus according to any one of claims 16 to 20, further comprising: 22. The apparatus further comprising means for causing at least re-formation and re-measurement of the pattern when it is determined that the pattern is not suitable for obtaining the adjustment value. Claims 16 to 1
10. The printing device according to any one of items 9. 23. The first print and the second print, wherein the print head performs reciprocal scanning with respect to the print medium to perform printing in forward scan and backward scan, respectively, and a plurality of the print heads. A first printhead and a second printhead, respectively, wherein the first and second printheads are printed in a direction relative to the print medium, and a plurality of prints. A direction different from a direction in which the first and second printheads are respectively scanned by the first and second printheads relative to the print medium, wherein the first and second printheads are respectively printed by the first printhead and the second printhead; Including at least one of the prints relating to The printing apparatus according to any one of claims 16 to 22, wherein 24. The adjustment value acquiring unit calculates the adjustment value by a calculation using a continuous value using linear approximation or polynomial approximation from the optical characteristic data obtained by the measurement unit. Claims 16 to 23
The printing device according to any one of the above. 25. A printing method according to claim 16, wherein said pattern forming means forms a pattern at a pitch that is less than a pitch of a printing position that can be controlled by a printing apparatus. apparatus. 26. The method according to claim 26, wherein the pattern forming unit includes the first unit.
By disposing dots by printing and dots by the second printing, and changing the positional relationship between the dots in accordance with the plurality of shift amounts to change the ratio of the dots covering the print medium, the shift amount The printing apparatus according to any one of claims 16 to 25, wherein a plurality of patterns exhibiting optical characteristics according to the following are formed. 27. A print head for performing the first print in which a plurality of printing elements for applying a printing agent to the print medium are arranged in-line at equal intervals in a direction different from the above-mentioned direction, and a printing agent for applying the printing agent to the printing medium. A plurality of print elements to be applied to the medium are arranged in line at equal intervals in a direction different from the above-described direction, and a print head for performing the second print is printed in a printing apparatus using the print head in parallel in the scanning direction. The printing apparatus according to any one of claims 16 to 26, wherein alignment is performed. 28. A print head for performing the first print uses a print agent using a print agent of at least one color, and a print head for performing the second print uses a plurality of print agents of at least one color different from the color tone. The printing apparatus according to claim 27, wherein the printing apparatus is a print head. 29. The printing apparatus according to claim 16, wherein the print head is a head that performs printing by discharging ink. 30. The printing apparatus according to claim 29, wherein the head has a heating element for generating thermal energy for causing film boiling of the ink as energy used for discharging the ink. 31. A printing apparatus that prints an image by using a print head and performing first and second printing with different dot formation position conditions on a print medium, and supplies the image data to the printing apparatus. A print system comprising: a host device; a pattern formed by the first print and the second print, wherein a plurality of shift amounts of a relative print position between the first print and the second print are provided. And a pattern forming means for forming a plurality of patterns on the print head, each of the plurality of patterns having optical characteristics corresponding to the plurality of shift amounts, respectively, and a position of each of the plurality of formed patterns. Measuring means for obtaining a plurality of data by measuring the optical characteristics a plurality of times differently; and for each of the plurality of patterns And obtaining an adjustment value for obtaining an adjustment value of a dot formation position condition between the first print and the second print based on the optical characteristics based on the plurality of data. Means, from the plurality of data obtained for each of the plurality of patterns, it is determined for each of the plurality of patterns that the pattern is formed in a state not suitable for obtaining the adjustment value, and the adjustment A printing system comprising: a determination unit that excludes a pattern formed in a state unsuitable for acquisition of a value from processing by the adjustment value acquisition unit. 32. The print system according to claim 31, wherein the adjustment value acquisition unit calculates an average value of the plurality of data to obtain an optical characteristic of the pattern. 33. The method according to claim 31, wherein the determining unit determines the presence of density unevenness occurring in the pattern from the plurality of data as a state unsuitable for acquiring the adjustment value. Print system as described. 34. When the difference between the maximum value and the minimum value of the plurality of data is greater than a predetermined value, the determination unit determines that the pattern is not suitable for acquiring the adjustment value. 31. The method according to claim 31, wherein the determination is made.
3. The print system according to any one of 3. 35. The pattern forming means forms a pattern more than the minimum necessary for the print position adjustment, and when it is determined that there is a pattern formed in a state not suitable for obtaining the adjustment value. 35. The print system according to claim 31, further comprising: a unit for providing an optical characteristic of another pattern to a process of acquiring the adjustment value. 36. If the exclusion does not provide a sufficient number of optical characteristics of the pattern to perform the adjustment value acquisition processing, a means for accepting manual adjustment for print registration is provided. The printing system according to any one of claims 31 to 35, further comprising: 37. The apparatus according to claim 37, further comprising means for performing at least re-formation and re-measurement of the pattern when it is determined that the pattern is not suitable for obtaining the adjustment value. Claims 31 to 3
5. The printing system according to any one of 4. 38. The first print and the second print, wherein the print head performs reciprocal scanning with respect to the print medium to perform printing in forward scan and backward scan, respectively, and a plurality of the print heads. A first printhead and a second printhead, respectively, wherein the first and second printheads are printed in a direction relative to the print medium, and a plurality of prints. A direction different from a direction in which the first and second printheads are respectively scanned by the first and second printheads relative to the print medium, wherein the first and second printheads are respectively printed by the first printhead and the second printhead; Including at least one of the prints relating to The printing system according to any one of claims 31 to 37, wherein: 39. The adjustment value acquiring unit calculates the adjustment value by a calculation using continuous values using linear approximation or polynomial approximation from the optical property data obtained by the measurement unit. Claims 31 to 38
The printing system according to any one of the above. 40. A printing method according to claim 31, wherein said pattern forming means forms a pattern at a pitch that is less than a pitch of a printing position that can be controlled by a printing apparatus. system. 41. The method according to claim 41, wherein:
By disposing dots by printing and dots by the second printing, and changing the positional relationship between the dots in accordance with the plurality of shift amounts to change the ratio of the dots covering the print medium, the shift amount The printing system according to any one of claims 31 to 40, wherein a plurality of patterns exhibiting optical characteristics according to are formed. 42. A print head for performing the first printing in which a plurality of printing elements for applying a printing agent to the print medium are arranged in-line at equal intervals in a direction different from the above-mentioned direction, and a printing agent for applying the printing agent to the printing medium. A plurality of print elements to be applied to the medium are arranged in line at equal intervals in a direction different from the above-described direction, and a print head for performing the second print is printed in a printing apparatus using the print head in parallel in the scanning direction. The printing system according to any one of claims 31 to 41, wherein alignment is performed. 43. A print head for performing the first print uses a print agent using a print agent of at least one color, and a print head for performing the second print uses a plurality of print agents of at least one color different from the color tone. The printing system according to claim 42, wherein the printing system is a print head. 44. The print system according to claim 31, wherein the print head is a head that performs printing by discharging ink. 45. The print system according to claim 44, wherein the head has a heating element that generates thermal energy that causes film boiling of the ink as energy used for discharging the ink.