JP2004066678A - Inkjet recording method and inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce density irregularities to be generated at recording image ends by suppressing a change of a coloring material density at the time of starting recording also when high image quality recording is carried out to a record medium of a large size. <P>SOLUTION: When multi-pass recording is carried out by scanning a recording head for jetting six kinds of ink of black, light cyan, cyan, light magenta, magenta and yellow by a plurality of the number of times to each recording region, the scanning is controlled to make the number of scanning times for recording with the use of dark ink of black, cyan and magenta smaller than the number of scanning times for recording with the use of light ink of light cyan, light magenta and yellow. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ink-jet recording method and an ink-jet recording apparatus, in particular, a recording head that ejects a plurality of types of inks including inks of similar colors and different densities, performs recording by scanning a plurality of times for each recording region, so-called The present invention relates to an inkjet printing method and an inkjet printing apparatus for performing multi-pass printing.
[0002]
[Prior art]
2. Description of the Related Art As an information output device in a word processor, a personal computer, a facsimile, or the like, a printer that records desired information such as characters and images on a sheet-like recording medium such as paper or film is widely used.
[0003]
Various methods are known as recording methods for printers, and an ink jet method has attracted particular attention in recent years.As a configuration, a recording head for ejecting ink in accordance with desired recording information is mounted and a paper The serial recording method of performing recording while reciprocating scanning in a direction intersecting the feeding direction of the recording medium, such as, for example, is generally widely used from the viewpoint of low cost and easy downsizing.
[0004]
2. Description of the Related Art As a conventionally known ink jet recording apparatus, a state change accompanied by a steep volume change (generation of bubbles) in an ink by applying an electric signal to a heating element (electric-thermal energy conversion element) near a discharge port. And a method in which ink is ejected from the ejection port by an action force based on this state change, or an ink is ejected from the ejection port (nozzle) by a change in ink pressure due to mechanical fluctuation using an electro-mechanical conversion element such as a piezoelectric element There is known a method of performing recording by causing ink droplets to adhere to a recording medium by a method of discharging ink.
[0005]
An ink jet recording apparatus equipped with this ink jet recording head (hereinafter, referred to as a recording head) can record a high-quality image at high speed and with low noise, and has a high density of discharge ports in the recording head. Therefore, it is possible to record a high-resolution image with a device that is small with respect to the size of the recording medium, and to easily obtain not only a black-and-white image but also a color image. .
[0006]
Therefore, a plurality of recording elements are integrated and arranged in the recording head, and a plurality of ink ejection ports and liquid paths are integrated to form a multi-nozzle. In order to cope with color recording, an ink using such a multi-nozzle recording head is used. It is common to provide a plurality according to the type.
[0007]
In addition, in order to realize image quality closer to silver halide photography, in addition to the four basic inks (black, cyan, magenta, and yellow) (hereinafter referred to as dark ink), the density is reduced with similar colors. By providing light ink (light cyan, light magenta, light black, and light yellow), light dots are formed from light portions to halftone portions of the image with light ink, and dark dots are formed from halftone portions to dark portions. A recording method in which ink dots are formed with ink has been proposed.
[0008]
FIG. 2 is a perspective view showing a configuration of a printer unit when printing is performed on a printing medium by the above-described multi-nozzle printing head. Here, as a configuration corresponding to color printing, a configuration having six printing heads in the main scanning direction corresponding to inks of six colors is shown.
[0009]
In this figure, the recording head 22 ejects ink of six colors of black (K), light cyan (LC), dark cyan (C), light magenta (LM), dark magenta (M), and yellow (Y). It is composed of six recording heads 22K, 22LC, 22C, 22LM, 22M, and 22Y.
[0010]
FIG. 3 shows a state of the ejection port array arranged on the recording head. Here, a black ink ejection port array is located at the left end, a light cyan ink ejection port row is adjacent to the black ink ejection port row, and then a cyan ink ejection port row. Are arranged.
[0011]
Before the start of printing, the print head 22 at the position (home position) in FIG. 2 receives the print start command and moves in the direction of arrow B (forward scan direction) while moving the print head 22 on the print medium, for example, the print paper 1. Is performed with a width corresponding to the range of the ejection port array. In this recording, the recording head 22 is driven based on the image signal in accordance with the read timing of the encoder 16, and ink droplets are ejected on the recording paper 1 in the order of black, light cyan, cyan, light magenta, magenta, and yellow, An image is formed by adhering. When printing for one scan in the direction of arrow B (forward scan direction) is completed, the recording head 22 returns to the original home position, and again returns to black, light cyan, cyan, light magenta, magenta, and yellow in the order of arrow B. (Forward scan direction). Alternatively, in the case of reciprocal printing, printing is performed in the order of yellow, magenta, light magenta, cyan, light cyan, and black while moving in the reverse direction of the arrow B toward the home position (return scan direction).
[0012]
In any case, after one recording operation (one scan) in one direction is completed and before the next recording operation is started, the conveying roller pair 3 is driven to move the recording paper 1 in the direction of arrow A. Quantitative, intermittent transport.
[0013]
By repeating the recording operation for one scan and the conveyance of a predetermined amount of recording paper, a desired image is recorded on the recording paper 1.
[0014]
In recent years, such an ink jet recording apparatus has been used in many office devices such as a printer, a copying machine, and a facsimile as an output unit thereof due to the spread of a personal computer, a word processor, and a facsimile in recent years. Output devices and even industrial systems such as printing and proofing, which take advantage of the image quality approaching silver halide photography, have come to be used.
[0015]
However, the recording heads used in such ink jet recording apparatuses have significantly improved the reliability of ejection and recording due to the progress of ejection performance, but the reliability has decreased under certain special conditions. May be. Specifically, there is a problem in that the change in the color material density in the ink at the start of printing makes the uniformity of the recording density at the edge of the recorded image unstable, resulting in uneven density at the edge of the recorded image.
[0016]
The density unevenness at the edge of the recorded image will be described with reference to an example shown in FIG. FIG. 4 shows an image image in which regular gradation image information is recorded on A4 size recording paper 1 by a conventional ink jet recording apparatus. This image does not necessarily have a regular gradation, but may be a basic halftone having a uniform density or a digital photographic image. The recording conditions are as follows. An image is formed by four recordings in the forward scanning direction using the recording heads 22 of the six colors described above, and a binarization process is performed using an error diffusion method in halftone expression. .
[0017]
In this case, the phenomenon that the recording density at the left end portion of the image on the recording paper 1 becomes high appears. An enlarged version is shown in the lower part of FIG. Although there is no change in the ejection amount ejected from each nozzle of the recording head 22, a dark ink droplet is ejected at the first ejection (first ejection) at the start of printing, and the second ejection and the third ejection are performed. As the ink is ejected, the ink drops return to the standard density.
[0018]
Factors that affect the change in the color material density of the ink at the start of printing include various properties of the ink, environmental conditions such as temperature and humidity, and use conditions of the print head.
[0019]
For example, in the case of extremely poor environmental conditions such as high temperature and low humidity, water evaporates from the ink near the discharge port, thereby reducing the water content in the ink near the nozzle and increasing the color material density of the ink. . In this state, the recording density is not stabilized until the ink affected by the vicinity of the nozzles is discharged, so that the density at the end is increased as described above, and the quality of the image at the start of recording is reduced.
[0020]
As a countermeasure against this, conventionally, the latitude (range) is narrow in order to reduce the change in the color material density of the ink at the start of recording, such as adjusting the viscosity or adjusting the color material or the solvent, mainly depending on the prescription of the ink. However, ink development has been carried out under various conditions.
[0021]
As a characteristic of the ink, when the fixing property (drying property) of the recorded image is prioritized, and a large amount of volatile components (such as alcohols) that impart dryness property to the ink is added to enhance the dryness property, Although the fixability is improved and the smear is reduced, the above-described change in the density of the coloring material of the ink at the start of recording is deteriorated. Therefore, the ink formulation is performed with a narrow latitude so that the fixability and the stability of the color material density of the ink at the start of recording are compatible to some extent.
[0022]
As a countermeasure in printhead control, the ink jet printing apparatus is provided with an ink receiver for preliminary ejection, and performs preliminary ejection for ejecting ink near the ejection ports at an arbitrary timing separately from recording as a recovery operation. Adjustment and execution of conditions such as the number of ejections and the number of ejections are also performed.
[0023]
The above countermeasures are quite common in current ink jet recording apparatuses, but in addition, for example, Japanese Patent Application Laid-Open No. Hei 4-39051 discloses that the first ejection, which is likely to deteriorate image reliability, is larger than usual. In order to apply thermal energy, the pulse width given to the discharge heater is increased, or a pre-pulse with a width that does not lead to the preceding discharge with a pause before the main pulse related to the discharge is used. There is also disclosed a method of discharging the ink having the increased density with a discharge amount that is superior to the flushness.
[0024]
By the above-described method, the problem of uneven density at the edge of a printed image as shown in FIG. 4 has been almost solved in the conventional ink jet printing apparatus.
[0025]
[Problems to be solved by the invention]
However, in recent years, there has been a strong demand for an ink jet recording apparatus to improve the image quality and increase the speed, and the demand for recording on a sheet larger in size than A4, which is usually used, has been increasing. In a printing apparatus, even when the above measures are taken, unevenness in density at the end of a printed image due to a change in color material density at the start of printing may be noticeable.
[0026]
In order to improve image quality, it is necessary to reduce the recording pixel size by reducing the amount of ink discharged at one time, and to improve the recording density by further reducing the nozzle pitch. Further, when multi-pass printing is performed by increasing the number of scans (the number of passes) for forming an image, the influence of the ejection characteristics of each nozzle is reduced and the ejection reliability is improved, so that the print quality is improved. On the other hand, it is effective to increase the number of nozzles to increase the printing width in one scan in order to increase the speed and print on a large-size sheet.
[0027]
In an ink jet printing apparatus employing such a configuration and control, depending on certain printing conditions, unevenness in density at the end of a printed image due to a change in the density of a color material at the start of printing becomes noticeable even when the above measures are taken.
[0028]
Specifically, when printing is performed on a large-size printing medium such as A3 by multi-pass printing using an inkjet printing apparatus capable of high-quality printing as described above, the density unevenness at the edge of the printed image is most likely to occur. stand out.
[0029]
In this case, for example, since the nozzles used in each scan are switched using a mask pattern or the like, some nozzles take a long time from the start of printing until the ejection operation is performed. In addition, since it takes time to perform printing in one scan, the time required from one ejection to the next ejection operation becomes longer. For this reason, the change in the color material density of the ink due to the evaporation of the water from the discharge port becomes larger than before.
[0030]
When multi-pass printing is performed on a large-sized printing medium with an ink-jet printing apparatus capable of high-quality printing in this manner, conventional measures cannot sufficiently cope with a change in the color material density. Density unevenness becomes noticeable.
[0031]
Further, physical properties such as viscosity and surface tension of the ink change depending on the temperature, thereby changing the amount of the ejected ink droplet (ejection amount). In particular, regarding the ejection amount, the ejection amount changes almost linearly with the temperature. Therefore, when the ink temperature is low, the ejection amount decreases, causing a decrease in recording density and density unevenness, and performing color recording. In some cases, the color and the like change.
[0032]
Therefore, in order to stabilize the discharge amount, temperature control (temperature control) for keeping the temperature of the ink constant is performed. However, the temperature control accelerates the evaporation of the water content of the ink from the discharge ports, so that the recording is started at the start of recording. There is another aspect that the change in the color material density is further deteriorated.
[0033]
By the way, in an ink jet recording apparatus that performs recording using a plurality of inks including the same color system having different densities, typically, black, light cyan, cyan, light magenta, magenta, and yellow inks, a high density The image is formed using two or more types of ink including black, cyan, and magenta among the dark inks in the dark portion, which is the portion of the dark portion. The amount is close to For this reason, even if the recording density changes due to the change in the color material density at the start of the recording, the density unevenness hardly appears in the high density dark area.
[0034]
Further, even in a light portion that is a low-density portion of the image area, since an image is generally formed by a combination of a light ink and a yellow ink, even if the color material density changes at the start of recording, It has been found that the change rate of the recording density in the low-density image area is low, and it is extremely difficult for the naked eye to visually recognize the change.
[0035]
On the other hand, in the halftone portion between the light portion and the dark portion in the image area, the dark ink, black, cyan, or magenta ink is added in addition to the portions where the light ink and yellow ink ejection amounts are close to 100%. Is gradually driven in, so that the change in the recording density due to the change in the color material density of these dark inks stands out as density unevenness.
[0036]
The present invention has been made in view of the above circumstances, and even when performing high-quality recording on a large-size recording medium, suppresses a change in color material density at the start of recording, and provides An object of the present invention is to provide an ink jet recording method and an ink jet recording apparatus which can reduce the generated density unevenness.
[0037]
[Means for Solving the Problems]
In order to achieve the above object, an ink jet recording method according to the first invention of the present application is to scan a recording head for ejecting a plurality of types of inks including inks of similar colors and different densities a plurality of times for each recording area. An inkjet recording method for performing recording,
The scanning is controlled such that the number of scans for printing using the dark ink is smaller than the number of scans for printing using the light ink.
[0038]
According to a second aspect of the invention, there is provided an ink-jet recording method in which a recording head for ejecting a plurality of types of inks including inks having similar colors and different densities is reciprocally scanned over each recording region a plurality of times. An ink jet recording method for performing recording by
The printing ratio is controlled so that the ratio of the data printed by the scanning in one direction is higher than the ratio of the data printed by the other scanning with respect to the data printed by the ink having a high density.
[0039]
Further, the above object is also achieved by an ink jet recording apparatus, a computer program, and a storage medium according to the above first and second inventions.
[0040]
That is, in the first invention of the present application, when a print head that ejects a plurality of types of inks including inks of the same color and different densities is printed by scanning a plurality of times for each print area, a high density print is performed. The scanning is controlled so that the number of scans for printing using ink is smaller than the number of scans for printing using ink with low density.
[0041]
In this way, for ink with a high density, the ratio of data recorded in one scan increases, and the ink droplets are continuously ejected and the ejection frequency increases, so that the ink is not used for recording. Is reduced, and it is possible to prevent the water content of the ink in the vicinity of the discharge port from evaporating and the color material density from changing.
[0042]
Further, in the second invention of the present application, when printing is performed by performing reciprocating scans of a plurality of types of inks including inks of similar colors and different densities on each recording area a plurality of times, the density of the recording head is reduced. The printing ratio is controlled such that the ratio of the data printed in one direction of the data printed by the dark ink is higher than the ratio of the data printed in the other scan.
[0043]
By doing so, the ratio of recording in one direction of scanning is increased, and in this direction, ink droplets are continuously ejected and the ejection frequency increases, so that the ink droplets are not used for recording. Is reduced, and it is possible to prevent the water content of the ink in the vicinity of the discharge port from evaporating, thereby preventing the color material density from changing. Further, in the other direction, the frequency used for the immediately preceding recording becomes almost equal, and the difference in the coloring material density due to the evaporation of the water content of the ink is reduced.
[0044]
Therefore, a problem occurs when performing high-quality printing in multi-pass, and it is possible to suppress the occurrence of density unevenness at image edges, which is conspicuous in a halftone portion from a bright portion to a dark portion of image density. However, high-quality recording with high quality can be performed.
[0045]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0046]
In the embodiment described below, a printer will be described as an example of a recording apparatus using an inkjet recording method.
[0047]
In the present specification, “recording” (sometimes referred to as “printing”) refers not only to forming significant information such as characters and figures, but also to meaningless or insignificant human perception. Regardless of whether or not the image is exposed, a case where an image, a pattern, a pattern, or the like is widely formed on a recording medium or a case where the medium is processed is also described.
[0048]
In addition, the term “recording medium” refers to not only paper used in general recording devices, but also a wide range of materials that can accept ink, such as cloth, plastic films, metal plates, glass, ceramics, wood, and leather. Shall be.
[0049]
Further, “ink” (sometimes referred to as “liquid”) is to be interpreted broadly as in the definition of “recording (printing)”, and when applied on a recording medium, an image or pattern , A liquid that can be used for forming a pattern or the like, processing a recording medium, or treating ink (for example, coagulation or insolubilization of a colorant in ink applied to a recording medium).
[0050]
First, the overall configuration and control configuration of an inkjet recording apparatus common to the embodiments described below will be described.
[0051]
FIG. 1 is an external perspective view of an ink jet recording apparatus according to the present invention. As shown in the drawing, the printing apparatus includes a carriage 11 in which a head cartridge in which a print head and an ink tank for storing ink are integrated is removably mounted, and a reciprocating movement of the carriage 11 (this movement direction is a main scanning direction). Direction), a belt 4 for transmitting the driving force of the carriage motor 12 to the carriage 11, a guide shaft 6 serving as a support for the carriage 11 to move in the main scanning direction, and electricity from a control unit (described later). A flexible cable 13 for transferring a signal to the recording head, a cap 141 and a wiper blade 143 used for performing a recording head recovery process, a cassette 15 for storing recording media (for example, recording paper) in a stacked state, An encoder sensor 16 for optically reading the position of the carriage 11 is provided.
[0052]
FIG. 2 is a perspective view showing the configuration near the carriage of the printing apparatus shown in FIG. 1 in more detail, and has the same configuration as the vicinity of the carriage of the conventional printing apparatus described above.
[0053]
The recording head 22 shown in FIG. 2 performs black (K), light cyan (LC), dark cyan (C), light magenta (LM), dark magenta ( M) and six recording heads 22K, 22LC, 22C, 22LM, 22M, and 22Y for ejecting six color inks of yellow (Y), respectively. The ink tank 21 includes recording heads 22K, 22LC, and 22C. , 22LM, 22M, and 22Y, and six ink tanks 21K, 21LC, 21C, 21LM, 21M, and 21Y for storing inks of corresponding colors. Correspondingly, the cap 141 includes six caps 141K, 141LC, 141C, 141LM, 141M, and 141Y for capping the ink ejection surface of each of the six print heads.
[0054]
When these recording heads and ink tanks are individually referred to, the reference numbers given to them are used, but when they are referred to comprehensively, the recording heads are referred to as “22”. ”,“ 21 ”for the ink tank, and“ 141 ”for the cap.
[0055]
Here, a head cartridge is constituted by the recording head and the ink tank. However, the head cartridge may be constituted integrally with the recording head and the ink tank, or may be constituted so as to be separable from each other.
[0056]
As shown in FIGS. 1 and 2, a carriage motor 12 is connected to the carriage 11 via the belt 4 and the burries 5a and 5b. Therefore, the carriage 11 reciprocally scans along the guide shaft 6 by driving the carriage motor 12.
[0057]
FIG. 3 is a view of the recording head 22 as viewed from the ejection port side, and has the same configuration as the recording head of the above-described conventional recording apparatus.
[0058]
As shown in FIG. 3, the recording heads 22K, 22LC, 22C, 22LM, 22M, and 22Y have a row of 1280 discharge ports at a density of 1200 dpi. These six recording heads are arranged in the main scanning direction. The ejection amount of ink ejected from each ejection port 23 at one time is about 4 ng.
[0059]
The opening areas of the ejection ports 23 of the six color inks are adjusted so as to minimize the ejection amount in order to realize high-quality recording.
[0060]
Hereinafter, the recording operation of the recording apparatus having the above configuration will be described in detail with reference to FIGS.
[0061]
First, a plurality of recording papers 1 stacked on the cassette 15 are supplied one by one by a paper feed roller (not shown). In the recording operation area, the recording papers 1 are moved between the recording head 22 and a platen (not shown). The sheet is conveyed to the conveying roller pair 3 with any high accuracy by an auxiliary conveying roller (not shown) such as another spur or roller.
[0062]
On the other hand, the ink is supplied from the ink tank 21, and the recording head 22 moves in the direction of arrow B (forward scan direction) in FIG. Record with. In this recording, an image is recorded by driving based on an image signal in accordance with a reading timing of the encoder 16 and discharging and attaching ink droplets onto the recording paper 1. Then, when printing for one scan in the direction of arrow B (forward scan direction) is completed, the print head 22 returns to the original home position and performs printing in the direction of arrow B (forward scan direction) again. After one recording operation (one scan) in one direction is completed and before the next recording operation is started, the conveying roller pair 3 is driven to intermittently move the recording paper 1 in the direction of arrow A by a predetermined amount. Transport to
[0063]
In this manner, an image is recorded on the recording paper 1 by repeating the recording operation for one scan and the conveyance of the recording paper by a predetermined amount.
[0064]
If necessary, the recording head 22 returns to the home position, and the clogging of the discharge port 23 is eliminated by the recovery mechanism. The cap 141 closes the discharge port 23 of the recording head 22 in order to prevent the ink suction operation when the discharge port 23 recovers or to prevent drying when the discharge port 23 is left, and the wiper blade 143 moves the discharge port 23 surface of the recording head 22 in the arrow C direction. Wiping while moving removes excess ink.
[0065]
Further, if the state in which printing is not performed continues to some extent, since the water content of the ink evaporates and the color material density of the ink near the ejection port increases, preliminary ejection is performed to eject the ink near the ejection port. This preliminary ejection is performed above an ink receiver (not shown) provided on the home position side.
[0066]
Next, a control configuration for executing the recording control of the above-described apparatus will be described.
[0067]
FIG. 5 is a block diagram showing a configuration of a control circuit of the ink jet recording apparatus according to the present invention. In the figure showing a control circuit, reference numeral 1700 denotes an interface for inputting a print signal, 1701 denotes a CPU, 1702 denotes a ROM for storing a control program and an error processing program executed by the CPU 1701, and 1703 denotes various data (the print signal and the print head). The RAM is a RAM for temporarily storing recording data supplied to the CPU 22. Reference numeral 1704 denotes a gate array (GA) for controlling supply of print data to the print head 22, and also controls data transfer between the interface 1700, the CPU 1701, and the RAM 1703. Reference numeral 12 denotes a carriage motor for transporting the recording head 22, and reference numeral 1709 denotes a transport motor for transporting the recording paper. Reference numeral 1705 denotes a head driver for driving the recording head 22, and 1706 and 1707 denote motor drivers for driving the transport motor 1709 and the carriage motor 12, respectively.
[0068]
The operation of the above control configuration will be described. When an image signal is input to the interface 1700, the image signal is converted between the gate array 1704 and the CPU 1701 into recording data for printing. Then, the motor drivers 1706 and 1707 are driven, and the recording head 22 is driven according to the recording data sent to the head driver 1705 to perform recording.
[0069]
In this example, the control program executed by the CPU 1701 is stored in the ROM 1702. However, an erasable / writable storage medium such as an EEPROM is further added, and the control program is changed from a host computer connected to the inkjet recording apparatus. It can be configured to be able to do so.
[0070]
In addition, the temperature control of the print head 22 is performed in accordance with a value obtained from a thermistor 1708 that detects an environmental temperature in which the printing apparatus is installed, in accordance with a value obtained by a discharge heater (not shown) for the CPU 1701 to discharge ink. A heater 1710 for controlling the temperature of the ink provided near the row is turned on / off, and the internal temperature of the print head output from a temperature sensor 1711 provided in the print head is monitored. Is done.
[0071]
An interface 1700 is an image processing unit (not shown) such as a connected host device, which converts an input image signal input in RGB or CMYK into print data for six colors of ink including dark ink and light ink. And an output image signal.
[0072]
The conversion in this processing is to convert the input image density signal level to the output image density signal level as shown in FIG. Here, for simplicity of description, a case will be described as an example in which two types of light cyan and dark cyan are used as the same color inks having different densities and the density signal level takes a value of 0 to 255.
[0073]
As shown in the figure, data conversion is performed such that only the light cyan is recorded for the input image density signal levels 0 to 128, and light cyan and dark data are converted for the input image density signal levels 129 to 255. Performs conversion such as recording in cyan. However, since the signal value obtained by adding the light cyan output density signal level and the dark cyan output density signal level for each of the input signals 129 to 255 is always 255, the light cyan output density signal level is inverted. Is a dark cyan signal, and conversely, a signal obtained by inverting the output density signal level of the dark cyan is a light cyan signal. Therefore, for the input density signal levels 129 to 255, only the table conversion for the input density signal level of light cyan or the table conversion for the input density signal level of dark ink is performed, so that the recording data for dark cyan and the conversion for light cyan are performed. Record data can be generated.
[0074]
Hereinafter, an embodiment of a recording method according to the present invention using the above-described inkjet recording apparatus will be described.
[0075]
<First embodiment>
In the first embodiment, when an image is printed by one-way multi-pass printing, the number of passes printed with dark ink of high density is made smaller than the number of passes printed with light ink of low density. It is.
[0076]
That is, in the conventional multi-pass printing, printing is performed with the same number of passes for all inks regardless of the density of the ink. In the present embodiment, however, black, light cyan, cyan, light magenta, magenta, and yellow are used. Prints an image using black, cyan, and magenta dark ink print data using fewer ink passes than the number of passes used to print an image using light cyan, light magenta, and yellow light ink print data. .
[0077]
In the following description, when performing four multi-pass printings in the forward direction, an image based on print data of black, cyan, and magenta dark inks is printed in two passes, and light cyan, light magenta, and yellow light are printed. An example in which an image based on ink print data is printed in four passes will be described.
[0078]
The operation in each pass (scan) of this embodiment will be described with reference to FIG. First, in the first scan, an image is printed by scanning the print head in the forward direction using black, light cyan, cyan, light magenta, magenta, and yellow inks. ÷ 2 = 50% of image data is recorded, and for light cyan, light magenta and yellow, 100 ÷ 4 = 25% of image data is recorded.
[0079]
After the scanning is completed, the recording head is returned to the original home position, and the recording paper is fed by 1280/4 = 320 nozzles. In the second scan, the print head is scanned in the forward direction using light cyan, light magenta, and yellow inks, and image data for 100/4 = 25% is printed.
[0080]
After the scanning, the recording head is returned to the original home position again, and the recording paper is fed by 1280/4 = 320 nozzles. In the third scan, the recording head is again scanned in the forward direction using black, light cyan, cyan, light magenta, magenta, and yellow inks to record an image. For black, cyan, and magenta, The image data of 100 ÷ 2 = 50% is recorded, and the image data of 100 シ ア ン 4 = 25% is recorded for light cyan, light magenta, and yellow.
[0081]
After the scanning is completed, the recording head is returned to the original home position, and the recording paper is fed by 1280/4 = 320 nozzles. In the fourth scan, the print head is scanned in the forward direction using light cyan, light magenta, and yellow inks, and image data corresponding to 100/4 = 25% is printed.
[0082]
A desired image is recorded on the recording paper 1 by repeating four scans and transporting a predetermined amount of recording paper on the recording area corresponding to the width of the recording head (1280 nozzles).
[0083]
Here, FIG. 7 shows a study image sample used for comparing an image printed by the conventional 4-pass printing with an image printed by the present embodiment.
[0084]
In the image shown in FIG. 7, a basic image of halftone is arranged for uniform density on the upper left and lower right sides of the A2 size recording paper 1 for density unevenness check, and the central portion thereof is located at the center thereof. , Halftone parts and characters with different densities were arranged. In this case, as described above, it is known that a low-density light portion and a high-density dark portion of an image are generally extremely difficult to see with the naked eye, so the halftone portion for density unevenness checking is changed from a bright portion to a dark portion. We decided to use the halftone part. Further, other halftone portions and characters are also constituted by print data for six color inks.
[0085]
The image shown in FIG. 7 is a result obtained by actually performing four forward scans in which print data of all six color inks are printed at an equal ratio, as conventionally performed, using an inkjet apparatus. is there.
[0086]
Looking at the halftone for density unevenness check disposed on the upper left side of the recording paper 1, it can be confirmed that the density unevenness described in the conventional example does not occur on the left side of the image end. This is because the ink whose color material density is changing near the discharge port is preliminarily ejected on the preliminarily ejected ink receiver provided on the left side (home position) of the recording paper 1 at a timing immediately before starting the recording by the forward scan. This is avoided by performing a recovery operation.
[0087]
However, it can be confirmed that the density unevenness described in the conventional example has occurred on the left side of the image end of the halftone portion for density unevenness check arranged on the lower right side of the recording paper 1. This is because, during printing in the forward scan, ink droplets ejected from the nozzles of the print head used for printing (ejection operation) until immediately before, such as printing of a character in the center or a halftone portion, and the space between characters and characters. Ink droplets ejected from the nozzles of the recording head that have not been used for recording (ejection operation) for a certain period of time cause a difference in color material density due to evaporation of ink moisture from the ejection openings, and recording for a certain period of time (ejection operation). This is because the recording density of the ink droplets ejected from the nozzles of the recording head which was not used in (1) has increased. As described above, this density unevenness is particularly conspicuous in a recording area using black, cyan, and magenta inks.
[0088]
On the other hand, when the same examination image sample as that of FIG. 7 is printed by the multi-pass printing according to the present embodiment, the image edge of the halftone portion for density unevenness check arranged on the upper left and lower right sides of the recording paper 1 is formed. It was possible to perform good recording without density unevenness on both the left and right sides.
[0089]
This is because the number of print scans for black, cyan, and magenta dark inks is reduced from four times to two times in the related art, so that double print data is printed in one scan. By continuously discharging ink droplets and increasing the frequency of discharge, the time during which each nozzle is not used for printing is reduced, and the water content of the ink near the discharge ports evaporates and This is because a change in material density can be prevented. This can be understood from the fact that even in the conventional multi-pass printing, when the number of scans for printing an image is extremely small, such as once or twice, density unevenness does not occur.
[0090]
As described above, in the present embodiment, the data to be printed with black, cyan, and magenta dark inks is printed in the forward scan two times, and the data to be printed with light cyan, light magenta, and yellow light inks. As a result of printing in the forward scan with four scans, there is a problem in performing high-quality printing with multi-pass, which is conspicuous in the halftone portion from the bright portion to the dark portion of the image density and the density unevenness at the image edge. It could be reduced and made inconspicuous.
[0091]
<Second embodiment>
In the first embodiment, multi-pass printing for completing an image by performing only scanning in the forward direction is performed. However, in the present embodiment, multi-pass printing for completing an image by performing reciprocal scanning is used.
[0092]
In the following description, when performing multi-pass printing in four round trips, an image based on print data of black, cyan, and magenta dark inks is printed in two passes in the forward direction, and light cyan, light magenta, and yellow are printed. An example in which an image based on print data of light ink is printed in four reciprocating passes will be described.
[0093]
The operation in each pass (scan) of this embodiment will be described with reference to FIG. First, in the first scan, an image is printed by scanning the print head in the forward direction using black, light cyan, cyan, light magenta, magenta, and yellow inks. ÷ 2 = 50% of image data is recorded, and for light cyan, light magenta and yellow, 100 ÷ 4 = 25% of image data is recorded.
[0094]
After the scanning, the recording paper is fed by 1280/4 = 320 nozzles. In the second scan, the print head is scanned in the backward direction using light cyan, light magenta, and yellow inks, and image data for 100/4 = 25% is printed.
[0095]
After the scanning, the recording paper is fed again by 1280/4 = 320 nozzles. In the third scan, the recording head is again scanned in the forward direction using black, light cyan, cyan, light magenta, magenta, and yellow inks to record an image. For black, cyan, and magenta, The image data of 100 ÷ 2 = 50% is recorded, and the image data of 100 シ ア ン 4 = 25% is recorded for light cyan, light magenta, and yellow.
[0096]
After the scanning, the recording paper is fed by 1280/4 = 320 nozzles. In the fourth scan, the print head is scanned in the backward direction using light cyan, light magenta, and yellow inks, and image data corresponding to 100/4 = 25% is printed.
[0097]
A desired image is recorded on the recording paper 1 by repeating four scans and transporting a predetermined amount of recording paper on the recording area corresponding to the width of the recording head (1280 nozzles).
[0098]
Here, FIG. 8 shows a study image sample used for comparing the effect of the present embodiment with the conventional multi-pass printing. The image shown in FIG. 8 is the same as that of the first embodiment shown in FIG. Are the same as described above.
[0099]
The image shown in FIG. 8 is a result obtained by actually performing four reciprocal scans in which print data of all six color inks are printed at an equal ratio, as conventionally performed, using an inkjet apparatus. is there.
[0100]
Looking at the halftone for density unevenness check arranged on the upper left side of the recording paper 1, the density unevenness described in the conventional example occurs on the left side of the image end similarly to FIG. 7 described in the first embodiment. You can see that it is not.
[0101]
However, the right side of the image end of the halftone for density unevenness check arranged on the upper left side of the recording paper 1 and the left side of the image end of the halftone for density unevenness check arranged on the lower right side are described in the conventional example. Density unevenness has occurred.
[0102]
On the other hand, when the same image sample for examination as shown in FIG. 8 is printed by the multi-pass printing according to the present embodiment, the right side of the image end of the halftone portion for density unevenness check arranged on the upper left of the recording paper 1 and the lower right Excellent recording was achieved in which density unevenness did not occur on both the left side of the image end portion of the halftone portion for density unevenness check arranged on the side.
[0103]
On the right side of the image end of the halftone portion for density unevenness check disposed on the upper left side of the recording paper 1, black, cyan, and magenta dark inks are used to record an image by scanning in both reciprocating directions in conventional multi-pass printing. On the other hand, in the present embodiment, since the image was recorded only in the forward scan, the ink droplet ejected from the nozzle used for recording immediately before, which occurred during the backward scan, was recorded for a certain period of time. This is because there was no difference in the color material density due to evaporation of the water content of the ink in the ink droplets ejected from the nozzles that were not used.
[0104]
Further, as for the left side of the image end portion of the halftone for density unevenness check arranged at the lower right side of the recording paper 1, double recording data is recorded by one scan as in the first embodiment. As a result, the ink droplets are continuously ejected from the nozzles of the recording head, and the ejection frequency increases, so that the time during which each nozzle is not used for recording is reduced, and the ink near the ejection port is reduced. This is because it is possible to prevent the water content from evaporating and the color material density from changing.
[0105]
As described above, in the present embodiment, data to be printed with black, cyan, and magenta dark inks is printed by two scans in the forward direction, and data to be printed with light cyan, light magenta, and yellow light inks is printed. As a result of recording in four reciprocal scans in both directions, the reciprocating scan also causes a problem when performing high-quality recording by multi-pass even when recording an image. The density unevenness at the edge of the image, which is conspicuous in the halftone portion, was solved.
[0106]
<Modification of First and Second Embodiments>
In the second embodiment, the printing scan direction of black, cyan, and magenta dark inks is always fixed to the forward scan. However, the same effect can be obtained by performing printing using the dark inks in the backward scan. Can be obtained.
[0107]
However, in this case, as described above, in order to eliminate clogging of the print head, preliminary discharge is performed at a timing immediately before the start of recording by forward scan in the preliminary discharge ink receiver generally arranged at the home position side. When reciprocating scanning is performed after the scanning, it is better to perform recording with black, cyan, and magenta dark inks in the forward scanning.
[0108]
Also, an ink receiver for preliminary ejection is arranged on the side opposite to the home position, and when reciprocating scanning is performed while performing preliminary ejection on both sides at the timing immediately before the start of printing on the forward path and the backward path, Good printing can be obtained by performing printing with black, cyan, and magenta dark inks in either scan.
[0109]
In the first and second embodiments, the number of scans for printing using dark inks of black, cyan, and magenta is set to two, and the number of scans for printing using light inks of light cyan, light magenta, and yellow is set. Is set to four times, but the number of scans is not limited to these numbers. For example, the number of scans for recording using dark ink of black, cyan, and magenta is set to two, and light inks of light cyan, light magenta, and yellow are used. Even if the number of scans is changed in accordance with a desired image density or image quality, for example, the number of scans for printing using is changed to eight, the same effect as in the above embodiment can be obtained.
[0110]
Further, as a modified example, of the total of six types of inks having different colors and densities, the number of scans of printing using the cyan and magenta dark inks is made smaller than the number of scans of printing using the light cyan and light magenta light inks. Even if the number is reduced, a good and uniform image can be obtained without the occurrence of density unevenness at the edge of a printed image as occurs in conventional multi-pass printing.
[0111]
As another modified example, when printing is performed using eight types of inks including light yellow and light black in addition to the above six types of inks, dark inks of black, cyan, magenta, and yellow are used. Even if the number of scans for printing is made smaller than the number of scans for printing using the light inks of light black, light cyan, light magenta, and light yellow, the density unevenness at the edge of the printed image as occurs in conventional multi-pass printing can be achieved. , And a good and uniform image can be obtained.
[0112]
<Third embodiment>
In this embodiment, in multi-pass printing in which an image is completed by scanning in both reciprocating directions, the ratio of data to be printed in forward scanning and the ratio of data to be printed in backward scanning are different values. .
[0113]
In the following description, when four reciprocating multi-pass printings are performed, 40% of the print data is printed by two forward scans, and 10% of the print data by two backward scans. Is described as an example.
[0114]
The operation in each pass (scan) of this embodiment will be described with reference to FIG. First, in the first scan, an image is printed by scanning the print head in the forward direction using black, light cyan, cyan, light magenta, magenta, and yellow inks. Do.
[0115]
After the scanning, the recording paper is fed by 1280/4 = 320 nozzles. In the second scan, the print head is scanned in the backward direction using black, light cyan, cyan, light magenta, magenta, and yellow inks to print 10% of image data.
[0116]
After the scanning, the recording paper is fed again by 1280/4 = 320 nozzles. In the third scan, the recording head is scanned in the forward direction using black, light cyan, cyan, light magenta, magenta, and yellow inks to record an image. Make a record.
[0117]
After the scanning, the recording paper is fed by 1280/4 = 320 nozzles. In the fourth scan, the print head scans in the backward direction using black, light cyan, cyan, light magenta, magenta, and yellow inks, and prints 10% of image data.
[0118]
A desired image is recorded on the recording paper 1 by repeating four scans and transporting a predetermined amount of recording paper on the recording area corresponding to the width of the recording head (1280 nozzles).
[0119]
Here, a description will be given of a study image sample used for comparing the effect of the present embodiment with the conventional multi-pass printing. The image sample recorded by the conventional multi-pass printing is the same as that of FIG. 8 described with respect to the second embodiment, and the right and left ends of the image unevenness check halftone arranged on the upper left of the recording paper 1 The density unevenness described in the related art occurs on the left side of the image end of the density unevenness check halftone arranged on the lower right side.
[0120]
On the other hand, when the same image sample for examination as shown in FIG. 8 is printed by the multi-pass printing according to the present embodiment, the right side of the image end of the halftone portion for density unevenness check arranged on the upper left of the recording paper 1 and the lower right Excellent recording was achieved in which density unevenness did not occur on both the left side of the image end portion of the halftone portion for density unevenness check arranged on the side.
[0121]
On the right side of the image end of the halftone portion for density unevenness check arranged on the upper left side of the recording paper 1, in the present embodiment, the ratio of recording the image in the forward scan is increased, so that it occurs during the backward scan. The color material density of the ink droplets ejected from the nozzles used for recording until immediately before and the ink droplets ejected from the nozzles that have not been used for recording for a certain period of time due to evaporation of the water content of the ink. This is because the difference has been reduced.
[0122]
On the left side of the image end of the halftone for density unevenness check arranged on the lower right side of the recording paper 1, the ratio of data recorded in the forward scan is increased, so that the ink droplets from the nozzles of the recording head are increased. As the ejection is performed continuously and the ejection frequency increases, the time during which each nozzle is not used for printing is reduced, and the water content of the ink near the ejection port evaporates and the color material density changes. It is because it can prevent that.
[0123]
As described above, in the present embodiment, when performing multi-pass printing with four reciprocating scans, the ratio of data to be printed in the forward scan is 40%, and the ratio of data to be printed in the backward scan is 10%. As a result, even when printing an image by performing reciprocal scanning, there is a problem in performing high-quality printing by multi-passing. It was possible to solve the density unevenness at the end.
[0124]
<Fourth embodiment>
In the third embodiment, the ratio of the data printed in the forward scan and the ratio of the data printed in the backward scan are set to different values for all the inks. Only for the dark ink, the ratio of the data printed in the forward scan and the ratio of the data printed in the backward scan are different values.
[0125]
In the following description, when performing multi-pass printing in four reciprocations, 40% of print data is printed for inks of high density in two forward scans, and two scans in the backward direction. An example in which 10% of the print data is printed for the dark ink will be described as an example.
[0126]
The operation in each pass (scan) of this embodiment will be described with reference to FIG. First, in the first scan, an image is recorded by scanning the recording head in the forward direction using black, light cyan, cyan, light magenta, magenta, and yellow inks. Prints 40% of image data, and prints light cyan, light magenta, and yellow light inks for 100% = 25% of image data.
[0127]
After the scanning, the recording paper is fed by 1280/4 = 320 nozzles. In the second scan, 10% of image data is recorded for black, cyan and magenta dark inks, and 100/4 = 25% for light cyan, light magenta and yellow light inks. Record the image data.
[0128]
After the scanning, the recording paper is fed again by 1280/4 = 320 nozzles. In the third scan, 40% of image data is recorded for dark ink of black, cyan, and magenta, and 100/4 = 25% of light ink of light cyan, light magenta, and yellow. Record the image data.
[0129]
After the scanning, the recording paper is fed by 1280/4 = 320 nozzles. In the fourth scan, 10% of image data is recorded for dark inks of black, cyan, and magenta, and 100 ÷ 4 = 25% for light inks of light cyan, light magenta, and yellow. Record the image data.
[0130]
A desired image is recorded on the recording paper 1 by repeating four scans and transporting a predetermined amount of recording paper on the recording area corresponding to the width of the recording head (1280 nozzles).
[0131]
Here, a description will be given of a study image sample used for comparing the effect of the present embodiment with the conventional multi-pass printing. The image sample recorded by the conventional multi-pass printing is the same as that of FIG. 8 described with respect to the second embodiment, and the right and left ends of the image unevenness check halftone arranged on the upper left of the recording paper 1 The density unevenness described in the related art occurs on the left side of the image end of the density unevenness check halftone arranged on the lower right side.
[0132]
On the other hand, when the same image sample for examination as shown in FIG. 8 is printed by the multi-pass printing according to the present embodiment, the right side of the image end of the halftone portion for density unevenness check arranged on the upper left of the recording paper 1 and the lower right Excellent recording was achieved in which density unevenness did not occur on both the left side of the image end portion of the halftone portion for density unevenness check arranged on the side.
[0133]
This is because the density unevenness occurring at the end of the halftone portion is mainly due to the difference in the color material density due to the evaporation of the moisture of the dense ink, so that only the dark ink has the forward direction and the backward direction. This is because the same effect as in the third embodiment can be obtained even if the recording ratio is changed.
[0134]
As described above, in the present embodiment, when performing multi-pass printing with four reciprocating scans, the ratio of data to be printed in the forward scan is set to 40% for only high-density ink, and printing is performed in the backward scan. As a result of setting the ratio of the data to be printed to 10%, even when printing an image by performing reciprocal scanning, there is a problem in performing high-quality printing by multi-pass, which is an intermediate portion of the image density from a bright portion to a dark portion. The density unevenness at the image edge, which is conspicuous in the toned portion, could be solved.
[0135]
<Modifications of Third and Fourth Embodiments>
In the fourth embodiment, the recording ratio in the forward direction is set to 40% and the recording ratio in the backward direction is set to 10% for black, cyan, and magenta inks. Even if only this is performed, a good and uniform image can be obtained without the occurrence of density unevenness at the edge of a printed image as occurs in conventional multi-pass printing.
[0136]
Similar effects can be obtained by using black, cyan, magenta, and yellow inks as the inks that increase the recording ratio in the forward direction.
[0137]
As another modified example, when printing is performed using eight kinds of inks including light yellow and light black in addition to the above six kinds of inks, a forward direction using black, cyan, magenta, and yellow dark inks is used. Even if the print ratio in the reverse direction is made higher than the print ratio in the backward direction, a good and uniform image can be obtained without the density unevenness at the edge of the printed image appearing in conventional multi-pass printing. Can be obtained.
[0138]
In the fourth embodiment, the ratio of recording in the forward direction using dark ink of black, cyan, and magenta is 40%, and the ratio of recording in the backward direction is 10%. However, recording in the forward direction is performed. The same effect can be obtained even if the ratio of recording in the backward direction is reversed to 10% and the ratio of recording in the backward direction is 40%.
[0139]
However, in this case, as described above, in order to eliminate clogging of the recording head, preliminary ejection is performed at a timing immediately before the start of recording by forward scan in the preliminary ejection ink receiver generally arranged on the home position side as described above. When reciprocal scanning is performed after the recording, it is better to increase the ratio of recording using dark ink in the forward direction.
[0140]
Also, an ink receiver for preliminary ejection is arranged on the side opposite to the home position, and when reciprocating scanning is performed while performing preliminary ejection on both sides at the timing immediately before the start of printing on the forward path and the backward path, Good printing can be obtained even if the ratio of printing using dark ink is increased in either scan.
[0141]
Further, in the third and fourth embodiments, the recording ratios in the forward direction and the backward direction are set to 40% and 10%, respectively. Of course, the ratio may be changed.
[0142]
<Other embodiments>
The present invention can be applied to all recording devices using recording media such as paper, cloth, nonwoven fabric, and OHP film, and specific application devices include office machines such as printers, copiers, and facsimile machines, and mass production machines. be able to.
[0143]
The above-described embodiment includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for causing ink to be ejected, particularly in an ink jet recording system. By using the method that causes the state change described above, it is possible to achieve high density and high definition of the recording, and the effect of the present invention is sufficiently exhibited.
[0144]
Regarding the typical configuration and principle, it is preferable to use the basic principle disclosed in, for example, US Pat. Nos. 4,723,129 and 4,740,796. This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or liquid path holding the liquid (ink). Applying at least one drive signal corresponding to the recording information and providing a rapid temperature rise exceeding the nucleate boiling, to generate heat energy in the electrothermal transducer, thereby causing the recording head to emit heat energy. This is effective in that film boiling occurs on the heat-acting surface of the liquid, and as a result, air bubbles in the liquid (ink) corresponding to the drive signal on a one-to-one basis can be formed. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed. When the driving signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of the liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable.
[0145]
As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.
[0146]
As the configuration of the recording head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (the linear liquid flow path or the right-angled liquid flow path) as disclosed in each of the above-mentioned specifications, a heat acting surface A configuration using U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600, which disclose a configuration in which is disposed in a bending region, is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slot is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, or an opening for absorbing a pressure wave of thermal energy is discharged. A configuration based on JP-A-59-138461, which discloses a configuration corresponding to each unit, may be adopted.
[0147]
Further, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length is satisfied by a combination of a plurality of recording heads as disclosed in the above specification. Either the configuration or the configuration as one recording head integrally formed may be used.
[0148]
In addition, not only the cartridge-type recording head in which the ink tank is provided integrally with the recording head itself described in the above embodiment, but also the electric connection with the apparatus main body by being attached to the apparatus main body. A replaceable chip-type recording head that can supply ink from the apparatus main body may be used.
[0149]
Further, the printing mode of the printing apparatus is not limited to a printing mode of only a mainstream color such as black, and may be a printing head integrally formed or a combination of a plurality of printing heads. The device may be provided with at least one of the full colors.
[0150]
In the above-described embodiment, the description has been made on the assumption that the ink is a liquid.However, even if the ink solidifies at room temperature or below, an ink that softens or liquefies at room temperature may be used. Alternatively, in the ink jet system, the temperature of the ink itself is controlled within the range of 20 ° C. to 70 ° C. to control the temperature so that the viscosity of the ink is in the stable ejection range. It is sufficient if the ink is sometimes in a liquid state.
[0151]
In addition, to prevent the temperature rise due to thermal energy from being used as the energy of the state change of the ink from the solid state to the liquid state, or to prevent the ink from evaporating, the ink solidifies in a standing state. Alternatively, ink that liquefies by heating may be used. In any case, the application of heat energy causes the ink to be liquefied by the application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start solidifying when it reaches the recording 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, as described in JP-A-54-56847 or JP-A-60-71260, the ink is held in a liquid state or a solid state in the concave portion or through hole of the porous sheet. It is good also as a form which opposes an electrothermal transducer. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.
[0152]
In addition to the above, the recording apparatus according to the present invention may include, as an image output terminal of an information processing apparatus such as a computer, an integrated or separate apparatus, a copying apparatus combined with a reader or the like, and a transmission / reception function. It may take the form of a facsimile machine.
[0153]
The present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but can be applied to a device including one device (for example, a copier, a facsimile machine, etc.) May be applied.
[0154]
Further, an object of the present invention is to supply a storage medium (or a recording medium) in which a program code of software for realizing the functions of the above-described embodiments is recorded to a system or an apparatus, and a computer (or a CPU or a CPU) of the system or the apparatus. Needless to say, the present invention can also be achieved by an MPU) reading and executing a program code stored in a storage medium. In this case, the program code itself read from the storage medium realizes the function of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. When the computer executes the readout program code, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instruction of the program code. It goes without saying that a part or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing.
[0155]
Further, after the program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the function is executed based on the instruction of the program code. It goes without saying that the CPU included in the expansion card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.
[0156]
【The invention's effect】
As described above, according to the present invention, with respect to ink having a high density, the ratio of data recorded in one scan increases, so that ink droplets are continuously ejected and the ejection frequency increases. In addition, the time during which the recording material is not used can be shortened, and it is possible to prevent the water content of the ink near the ejection port from evaporating and the color material density from changing.
[0157]
Therefore, a problem occurs when performing high-quality printing in multi-pass, and it is possible to suppress the occurrence of density unevenness at image edges, which is conspicuous in a halftone portion from a bright portion to a dark portion of image density. However, high-quality recording with high quality can be performed.
[Brief description of the drawings]
FIG. 1 is an external perspective view of an inkjet recording apparatus according to the present invention.
FIG. 2 is a perspective view illustrating a configuration near a carriage of the recording apparatus illustrated in FIG. 1 in more detail.
FIG. 3 is a diagram of the recording head 22 as viewed from a discharge port side.
FIG. 4 is a diagram illustrating density unevenness at an image edge caused by conventional multi-pass printing.
FIG. 5 is a block diagram illustrating a configuration of a control circuit of the printing apparatus of FIG. 1;
FIG. 6 is a diagram illustrating a process of converting an image density level into a light and dark ink performed in the image processing.
FIG. 7 is a diagram showing an image in which a study image sample for examining density unevenness at an image end is recorded by conventional multi-pass printing.
FIG. 8 is a diagram showing an image in which a study image sample for studying density unevenness at an image end is recorded by another conventional multi-pass printing.
FIG. 9 is a diagram for explaining multi-pass printing according to the first embodiment.
FIG. 10 is a diagram illustrating multi-pass printing according to a second embodiment.
FIG. 11 is a diagram for explaining multi-pass printing according to a third embodiment.
FIG. 12 is a diagram for explaining multi-pass printing according to a fourth embodiment.
[Explanation of symbols]
1 Recording paper
3 Transport roller pair
4 belt
5a, 5b pulley
6 Guide shaft
11 Carriage
12 Carriage motor
13 Flexible cable
15 cassettes
16 Optical position sensor
21 Ink tank
22 Recording head
23 Discharge port
141 cap
143 Wiper blade
1700 interface
1701 CPU
1702 ROM
1703 RAM
1704 G.P. A.
1705 Head driver
1706, 1707 Motor driver
1708 Thermistor
1709 Transport motor
1710 Heat insulation heater
1711 Temperature sensor

Claims (18)

An ink jet recording method for performing recording by scanning a recording head that ejects a plurality of types of inks including inks having different densities of similar colors in each recording region a plurality of times,
An ink-jet recording method, comprising: controlling the scanning so that the number of scans for performing recording using ink having a high density is smaller than the number of scans for performing recording using ink having a low density. The recording is performed by performing the scanning in both the reciprocating directions.
2. The ink jet recording method according to claim 1, wherein control is performed such that only the ink having the higher density is used in scanning in one direction, and all inks are used in scanning in the other direction. 3. The ink-jet recording method according to claim 1, wherein the dark ink includes magenta and cyan inks, and the light ink includes light magenta and cyan inks. 4. The ink jet recording method according to claim 3, wherein the dark ink further includes a black ink, and the light ink further includes a yellow ink. 5. The ink-jet apparatus according to claim 1, wherein a preliminary ejection operation for ejecting ink near an ink ejection port is performed before scanning for performing recording using the high-density ink. Recording method. 6. The ink jet recording head according to claim 1, wherein the recording head ejects ink by using thermal energy, and includes a thermal energy converter for generating thermal energy to be applied to the ink. The inkjet recording method according to any one of the above items. An ink jet recording apparatus that performs recording by scanning a recording head that ejects a plurality of types of inks including inks having different densities of similar colors in each recording region a plurality of times,
An ink jet printing apparatus comprising: a scanning control unit that controls the number of scans for performing printing using ink having a high density so that the number of scans for performing printing using ink having a low density is reduced. Recording device. A computer program for realizing, by a computer, an ink jet recording method for performing recording by scanning a recording head that ejects a plurality of types of inks including inks having different densities of similar colors in each recording region a plurality of times,
A program code for causing a computer to execute a step of controlling scanning so that the number of scans for printing using the dark ink is smaller than the number of scans for printing using the light ink. Characteristic computer program. A storage medium storing the computer program according to claim 8. An ink jet recording method for performing recording by performing reciprocating scanning a plurality of times with respect to each recording region, a recording head that discharges a plurality of types of inks including inks having different densities of similar colors,
For data recorded by ink with a high density, it is necessary to control the recording ratio such that the ratio of data recorded in one direction of scanning is higher than the ratio of data recorded in the other scanning. Characteristic ink jet recording method. 11. The ink jet recording method according to claim 10, wherein control is performed such that the ratio of data recorded in all scans of the inks other than the dark ink is equal. 12. The ink jet recording method according to claim 10, wherein the dark ink includes magenta and cyan inks, and the light ink includes light magenta and light cyan inks. 13. The ink-jet recording method according to claim 12, wherein the dark ink further includes a black ink, and the light ink further includes a yellow ink. 14. A pre-ejection operation for ejecting ink near an ink ejection port is performed before scanning in a direction in which a ratio of data recorded with the dark ink is high. Item 2. The inkjet recording method according to item 1. 15. The ink jet recording head according to claim 10, wherein the recording head ejects ink by using thermal energy, and includes a thermal energy converter for generating thermal energy to be applied to the ink. The inkjet recording method according to any one of the above items. An ink jet recording apparatus that performs recording by reciprocatingly scanning a recording head a plurality of times including a plurality of types of inks including inks having similar colors and different densities, for each recording area,
Control means for controlling the recording ratio such that the ratio of the data recorded by scanning in one direction is larger than the ratio of the data recorded by the other scanning, with respect to the data recorded by the ink having a high density. An ink jet recording apparatus comprising: A computer program for realizing, by a computer, an ink jet recording method of performing recording by reciprocatingly scanning a recording area a plurality of times including a plurality of types of inks including inks having different densities of similar colors and performing recording.
The step of controlling the recording ratio such that the ratio of the data recorded by scanning in one direction is higher than the ratio of the data recorded by the other scanning, with respect to the data recorded by the ink having a high density. A computer program comprising a program code to be realized by a computer. A storage medium storing the computer program according to claim 17.

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