JP2003062988A - Printing for suppressing stripping of dot from print medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance fixing properties of ink in a printing using ink exhibiting bad fixing properties to a print medium. SOLUTION: In a printing using an ink exhibiting good fixing properties to a print medium and an ink exhibiting bad fixing properties to the print medium, fixing properties of ink can be enhanced for the print medium by superposing a dot of the ink exhibiting good fixing properties on a dot formed of the ink exhibiting bad fixing properties on the print medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for forming ink dots on a print medium while performing main scanning of a print head.

[0002]

2. Description of the Related Art Recently, as an output device of a computer,
Color printers that eject a plurality of colors of ink from a print head have become widespread. Dye inks and pigment inks are used as a plurality of colors of ink used in a color printer. Here, the "dye ink" is an ink that uses a dye as a colorant of the ink, and the "pigment ink" is
It is an ink that uses a pigment as a colorant of the ink.

The use of dye ink has the advantage that a transparent color can be expressed on the print medium. On the other hand, when the pigment ink is used, there is also an advantage that it is possible to print characters and images with less bleeding.

[0004]

However, when printing on plain paper using a pigment ink, there is an advantage that characters and images with less bleeding can be printed.
In particular, when a pigment-based ink is printed on a film-based printing medium containing a film as a material, there is a problem that the ink is easily peeled off after drying, that is, the fixing property is poor. Further, such a problem is not limited to a pigment-based ink or a film-based printing medium, but is a problem that generally occurs when the fixing property is poor on the printing medium.

The present invention has been made to solve the above-mentioned problems in the prior art, and an object of the present invention is to improve the fixability of ink in printing using ink having poor fixability to a print medium. And

[0006]

In order to solve at least a part of the above-mentioned problems, a print control apparatus of the present invention forms dots on a print medium while performing main scanning of a print head. A print controller for generating print data to be supplied to the printing unit to perform printing using the printing unit, wherein the print head is relatively easy to peel off from the print medium after drying. Nozzle of the first type for ejecting the first type of ink for forming the second dot, and the second type of ink for forming the second type of dot that is relatively hard to peel off from the print medium after drying. A second type nozzle group for performing main scanning, and the print control device according to print target image data representing a print target image, raster data indicating a dot recording state at each main scan, and each main scan. In between And a print data generation unit that generates print data including sub-scan feed data that represents a sub-scan feed amount, and the print data generation unit outputs the print data to at least a part of the dots of the first type. A configuration in which the printing unit executes printing so that the number of dots of the second type formed by overlapping from above is larger than the number of dots of the second type formed below the dots of the first type It is characterized in that it is generated to have.

According to the print control apparatus of the present invention, since the ink having good fixability is superposed on the ink having poor fixability to the print medium, the fixability of ink to the print medium can be improved.

In the above print control apparatus, the print data generating section may be configured such that, when the print medium is a specific print medium, the print data generating section is formed by overlapping at least a part of the dots of the first type. So that the ratio of the two types of dots to the second type dots formed under the first type dots is larger than that when printing on a print medium other than the specific print medium, It is preferable to generate the print data.

In this way, when printing on a specific print medium, when dots with good fixability formed by overlapping at least a part of dots with poor fixability are printed on another print medium. Since the print data is generated so as to be larger than that, it is possible to cause the printer to perform printing that improves the ink fixability only when printing on a print medium having poor ink dot fixability, for example.

In the above print control device, the print data generation unit may print the print data on the specific print medium other than the specific print medium for the first type nozzle group. It is preferable that the nozzles located on the upstream side in the sub-scanning direction are used for printing as compared with the case of printing on the printing medium.

With this configuration, when printing on a specific print medium, dots having poor fixability are generated by using nozzles located on the upstream side in the sub-scanning direction as compared with printing on another print medium. Since the dots are formed, the ratio of dots having good fixing properties formed on the dots having poor fixing properties is increased. As a result, it is possible to easily improve the fixability of the ink on the specific print medium.

In the above print control device, the print data generation unit is configured to print the print data for the second type nozzle group on a specific print medium other than the specific print medium. It is preferable that the nozzles located on the downstream side in the sub-scanning direction are used for printing as compared with the case of printing on the printing medium.

With this configuration, when printing on a specific print medium, dots having good fixability are formed by using nozzles located on the downstream side in the sub-scanning direction as compared with printing on another print medium. Since the dots are formed, the ratio of dots having good fixing properties formed on the dots having poor fixing properties is increased. As a result, it is possible to easily improve the fixability of the ink on the specific print medium.

In the above print control apparatus, the print data generation unit converts the print target image data from the first color system into a second color system for ink used in the print head. When the print medium is a specific print medium, the color conversion unit includes the first
The specific print medium has a ratio of the dots of the second type, which are formed by overlapping at least a part of the dots of the type, to the dots of the second type formed below the dots of the first type. It is preferable to perform color conversion so that the color conversion becomes larger than that in the case of printing on a printing medium other than the above.

With this configuration, when printing is performed on a specific print medium, the ink amount per unit area of the ink having good fixability ejected after the ink having poor fixability is printed on another print medium. Color conversion is performed so that the number is larger than the case. With this configuration, the degree of improvement in ink fixability can be finely set by adjusting the contents of the color conversion table.

In the above print control device, the color conversion section stores a color conversion table storage section for storing a plurality of color conversion tables including a specific color conversion table used for printing on the specific print medium. When printing on the specific print medium, a color conversion table selection unit that selects the specific color conversion table is provided, and the specific color conversion table includes at least a part of the dots of the first type. The first type of dots of the second type formed by overlapping from above
It is preferable that the ratio of the dots of the second type formed under the dots of the type is set to be larger than that of the color conversion tables other than the specific color conversion table.

In this configuration, by selecting and using the color conversion table, it is possible to change the recording rate per unit area of the dots having good fixability formed on the dots having poor fixability, so that the printing can be performed. The processing load in data generation can be reduced.

In the above print control device, the print control device is configured such that the recording rate per unit area of the dots of the second type formed after the dots of the first type are formed at an arbitrary position of the print medium. However, it is preferable that the print data be generated so that the print data becomes larger than a predetermined ratio.

In general, the type of ink used for expressing a print image differs depending on the image to be printed. By doing so, a dot having a good fixing rate can be formed by superimposing dots having a low fixing rate. Since the recording rate per unit area is always higher than the predetermined rate, the ink fixability can be improved stably.

In the above print control apparatus, it is preferable that the predetermined ratio is 60%.

By doing so, it is possible to almost eliminate the peeling of the dots from the print medium, so that even if the print surface is rubbed by hand after the ink is dried, almost no ink can reach the hand.

In the above print control apparatus, the specific print medium may be a film type print medium or a surface layer of a resin data recording medium.

Since the film-type print medium and the resin-made data recording medium such as CD-R generally have a poor ink fixing property, the effect of applying the present invention can be remarkably obtained. In the present specification, a print medium such as a dedicated OHP sheet, a glossy film, or a SF backlight film, which is used as a print medium surface on which a film that hardly absorbs ink adheres, is referred to as a film-based print medium. Call. The printing medium is also called printing paper.

In the print control device, the first type ink may be an ink using a pigment as a coloring material, or may be a black ink.

Since the ink using a pigment as a coloring material generally has a poor fixing property to a printing medium, the effect of the application of the present invention can be remarkably obtained. In addition, since the pigment ink can express a clear outline, it is preferable to use the pigment ink as a color material for the black ink.

The present invention can be implemented in various modes, for example, a printing method and a printing device,
Print control method and print control apparatus, computer program for realizing functions of those methods or apparatuses,
It can be realized in the form of a recording medium recording the computer program, a data signal containing the computer program and embodied in a carrier wave, or the like.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described in the following order based on examples. A. Device Configuration: B. Printing Process of First Embodiment: C.I. Printing process of the second embodiment: D. Printing Process of Third Embodiment: E. Color conversion table generation processing: F. Modification:

A. Device Configuration: FIG. 1 is a block diagram showing the configuration of a printing system as an embodiment of the present invention. This printing system includes a computer 90 as a print control device, a color printer 20 as a printing unit,
Is equipped with. The combination of the color printer 20 and the computer 90 can be called a “printing device” in a broad sense.

In the computer 90, the application program 9 is executed under a predetermined operating system.
5 is working. A video driver 91 and a printer driver 96 are incorporated in the operating system, and the application program 95 outputs print data PD to be transferred to the color printer 20 via these drivers. The application program 95 performs desired processing on the image to be processed, and also displays the image on the CRT 21 via the video driver 91.

When the application program 95 issues a print command, the printer driver 9 of the computer 90
6 receives the image data from the application program 95 and converts it into print data PD to be supplied to the color printer 20. In the example shown in FIG. 1, inside the printer driver 96, a resolution conversion module 97, a color conversion module 98, a halftone module 99, a rasterizer 100, and a color conversion table L.
A UT and a print mode selection unit 101 are provided.

The resolution conversion module 97 plays a role of converting the resolution (that is, the number of pixels per unit length) of the color image data handled by the application program 95 into a resolution that can be handled by the printer driver 96. The image data whose resolution has been converted in this way is still image information consisting of three colors of RGB. The color conversion module 98 converts the RGB image data into multi-tone data of a plurality of ink colors usable by the color printer 20 for each pixel while referring to the color conversion table LUT. In this example, a plurality of color conversion table LUTs are provided, the reason for which will be described later.

The color-converted multi-gradation data is, for example, 25
It has 6 gradation values. The halftone module 99 disperses and forms ink dots,
The color printer 20 executes halftone processing for expressing the gradation value. The image data that has undergone halftone processing is processed by the rasterizer 100 in the color printer 2
The data is rearranged in the order of data to be transferred to 0, and is output as final print data PD. The print data PD
Includes raster data indicating a dot recording state in each main scan and data indicating a sub-scan feed amount. In addition,
The function of the print mode selection unit 101 will be described later.

The printer driver 96 corresponds to a program for realizing the function of generating the print data PD. The program for realizing the functions of the printer driver 96 is supplied in the form recorded in a computer-readable recording medium. Examples of such a recording medium include a flexible disk, a CD-ROM, a magneto-optical disk, an IC card, a ROM cartridge, a punch card, a printed matter on which codes such as a bar code are printed, and an internal storage device (RAM, ROM, etc.) of a computer. memory)
Also, various computer-readable media such as an external storage device can be used.

FIG. 2 is a schematic block diagram of the color printer 20. In the color printer 20, the sub-scan feed mechanism that conveys the print paper P in the sub-scan direction by the paper feed motor 22 and the axial direction of the discharge side sub-scan feed mechanism 27 included in the sub-scan feed mechanism by the carriage motor 24. A main scanning feed mechanism that reciprocates in the (main scanning direction), and a print head unit 60 mounted on the carriage 30.
Signals from a head drive mechanism that drives (also referred to as “print head assembly”) to control ink ejection and dot formation, and the paper feed motor 22, carriage motor 24, print head unit 60, and operation panel 32. And a control circuit 40 that controls the exchange of Control circuit 4
0 is connected to the computer 90 via the connector 56.

The sub-scan feed mechanism for conveying the printing paper P is
A gear train (not shown) for transmitting the rotation of the paper feed motor 22 to a paper feed side sub-scan feed mechanism, a paper discharge side sub-scan feed mechanism 27, and a paper transport roller (not shown), which will be described later, is provided. Further, a main scanning feed mechanism for reciprocating the carriage 30 is provided in parallel with a shaft of the paper discharge side sub-scan feed mechanism 27, and a sliding shaft 34 for slidably holding the carriage 30.
A pulley 38 that stretches an endless drive belt 36 between the carriage motor 24 and a position sensor 39 that detects the origin position of the carriage 30 is provided.

FIG. 3 is a side sectional view showing a sub-scan feed mechanism for conveying the printing paper P. The sub-scan feed unit has a paper feed side sub-scan feed mechanism 25 provided on the paper feed side and a paper ejection side sub-scan feed mechanism 27 provided on the paper ejection side. The paper feed side sub-scan feed mechanism 25 includes a paper feed roller 25a and a driven roller 25b. Paper ejection side sub-scan feed mechanism 2
7 is composed of a paper discharge roller 27a and a serrated roller 27b. These rollers 25a, 25b, 27a, 27b
Is driven by the rotation of the paper feed motor 22 (FIG. 2) being transmitted via a gear train (not shown).

At the start of printing, the printing paper P is sandwiched from the paper feed side (right side in FIG. 3) by the rollers 25a and 25b of the paper feed side sub-scan feed mechanism 25, and the sub-scan feed is performed by the rotation of both rollers. Be seen. When the leading edge of the print sheet P is nipped by the rollers 27a and 27b of the sheet discharge side sub-scan feed mechanism 27, these rollers also feed the sheet to the sheet discharge side. Further, after the trailing edge of the print sheet P has passed the point sandwiched by the rollers 25a and 25b of the paper feed side sub-scan feed mechanism 25, the print sheet P is only printed by the paper discharge side sub-scan feed mechanism 27.
Will be sent. An image is recorded on the printing paper P by the print head 28 on the platen 26.

In this specification, the upstream side and the downstream side of the printing paper or the nozzle array are defined according to the paper feeding direction (sub-scanning direction). The paper feed direction and the sub-scanning direction are defined as the directions in which the print paper P moves relative to the printer 20 during the sub-scanning.

FIG. 4 is an explanatory view showing the nozzle arrangement on the lower surface of the print head 28 in the first embodiment of the present invention. The lower surface of the print head 28 is provided with a color nozzle row and a black nozzle row. In the color nozzle row, a cyan nozzle group C for ejecting cyan ink
, A magenta nozzle group M for ejecting magenta ink, and a yellow nozzle group Y for ejecting yellow ink are arranged in the sub-scanning direction. The black nozzle row includes only the black nozzle group K for ejecting black ink.

The cyan nozzle group C includes nozzles # C1 to # C1.
5 has a plurality of nozzles arranged in the sub-scanning direction, and the magenta nozzle group M includes nozzles # M1 to # M1.
5, the yellow nozzle group Y includes the nozzles # Y1 to # Y15,
Each has a plurality of nozzles arranged along the sub-scanning direction. On the other hand, the black nozzle group K has nozzle # K1.
To # K48 have a plurality of nozzles arranged in the sub-scanning direction. Of these, only the upstream nozzles # K33 to # K47 are used in this embodiment.

In this embodiment, since the black ink is an ink containing a pigment as a colorant, it has a property of being easily peeled off from the print medium after drying when printed on a film-type print medium. There is. The cyan ink, the magenta ink, and the yellow ink are inks containing a dye as a colorant, and therefore have a property of being relatively hard to be peeled off from the print medium after being dried.

Further, since these color inks use a resin as a vehicle for carrying and fixing the color material to the print medium, they have a property that they are not easily peeled off from the print medium. This is because the resin covers and fixes the color material on the print medium after drying. Therefore, when such an ink lands on at least a part of the ink dots that are easily peeled off from the print medium after drying, it is possible to cover the previously formed dots and fix them to the print medium. .

In this embodiment, the black nozzle group K
Corresponds to the "first type nozzle group" in the claims, and the cyan nozzle group C, the magenta nozzle group M, and the yellow nozzle group Y correspond to the "second type nozzle group" in the claims. To do.

On the other hand, as shown in FIG. 3, the nozzles # K33 to # K47 used in the black nozzle group K are arranged on the upstream side of the magenta nozzle group M and the yellow nozzle group Y in the sub-scanning direction. Therefore, magenta dots and yellow dots are formed on the black dots in the pixels where the black dots are formed and the pixels around the black dots so as to overlap each other. As a result, the black dots that are easily peeled off from the print medium are formed first, and the color dots that are hard to peel off are formed on top of each other.

In the forward unidirectional printing, since the black nozzle group K is arranged at the position where dots are formed before the cyan nozzle group C in the main scanning direction, black dots are formed. In the pixel, color dots are formed in an overlapping manner on the black dots.
However, for the pixels around the pixels where the black dots are formed, the cyan dots may be formed first.

For example, in a pixel in which the black nozzle # K33 forms a dot, the cyan nozzle # C1 forms a dot after the dot is formed. However, in the peripheral pixels of the pixels where the black nozzle # K33 forms a dot, the cyan nozzle #C is formed before the black dot is formed.
14 and # C15 may form dots. This is because there is a cyan nozzle that is arranged on the upstream side of the black nozzle in terms of nozzle units.

Each nozzle is provided with a piezo element (not shown) as a drive element for driving each nozzle to eject ink droplets. During printing, ink droplets are ejected from each nozzle while the print head 28 moves in the main scanning direction.

The plurality of nozzles in each nozzle group need not be arranged in a straight line along the sub-scanning direction.
For example, they may be arranged in a staggered pattern. In this specification, "a plurality of nozzles arranged in the sub-scanning direction"
The wording has a broad meaning including nozzles arranged in a straight line and nozzles arranged in a staggered pattern.

The color printer 20 having the above-described hardware configuration conveys the paper P by the paper feed motor 22 and reciprocates the carriage 30 by the carriage motor 24, and at the same time drives the piezo element of the print head 28. , Ink droplets of each color are ejected to form ink dots, and a multi-color multi-tone image is formed on the paper P.

B. Printing Process of First Embodiment: FIG. 5 is a flowchart showing a printing process procedure in the first embodiment of the present invention. In step S101, the user instructs the computer 90 to print. Further, when the "property button" (not shown) in the printing dialog box displayed on the CRT 21 is clicked in step S102, the print mode selection unit 101 (FIG. 1) causes the property setting screen shown in FIG. To display.

The user can specify various parameters for defining the print mode on the property setting screen. The print mode basic setting screen shown in FIG. 6 includes the following elements for designating various parameters. (1) Paper type menu PM: A pull-down menu for selecting one from plain paper, special paper, or special OHP sheet. (2) Ink color selection button CLR: A button for selecting whether to use color ink or only black ink.

It should be noted that the user can set other parameters other than these on the detailed setting screen of the print mode, but the description of these other parameters will be omitted below.

In step S103 of FIG. 5, when the user sets various parameters of the print mode and gives an instruction to start printing, in step S104, it is used in the color conversion process according to the type of the selected print medium. Color conversion table LUT is selected. Specifically, when the dedicated OHP sheet is selected, the color conversion table LUT for the film print medium is selected. The color conversion table LUT selected in this way is used throughout the print job.

Here, the color conversion table LUT for the film type print medium has color dots (magenta dots and yellow dots) formed after the black dot at an arbitrary position on the print medium where the black dot is formed. Is a table set so that the recording rate per unit area is always higher than a predetermined value. A method of generating the color conversion table LUT for the film print medium will be described later.

When a film-type print medium is selected as the print medium, the ink color selection button CLR is automatically switched to color. The reason why the ink color selection button CLR is automatically switched to color is that printing is performed using color ink in order to improve the fixability of the ink on the print medium. In this embodiment, as shown in FIG. 6, the user is notified of that fact.

In step S105 of FIG. 5, the printer driver 96 performs color conversion processing using the color conversion table LUT selected in step S104 to generate print data. In step S106, the printer 20 executes printing according to the print data supplied from the computer 90.

As described above, in the first embodiment, the print head 28 having a nozzle array is used in which black dots that are easily peeled from the print medium are formed and more color dots that are difficult to be peeled off are formed. At the same time, since the color conversion is performed so that the recording rate per unit area of the color dots that are overlapped from the black dots is always a predetermined value or more, it is preferable that the ink has poor fixability on the print medium. In the printing using the ink, the fixability of the ink on the print medium can be improved.

C. Printing Process of Second Embodiment: FIGS. 7 and 8 are explanatory views showing the nozzle arrangement on the lower surface of the print head 28 in the second embodiment of the present invention. FIG. 7 shows a case where the print medium is plain paper, and FIG. 8 shows a case where the print medium is a film-based print medium. The second embodiment differs from the first embodiment in that the black nozzles used according to the print mode are shifted in the sub-scanning direction.

Specifically, when the print medium is plain paper, the nozzles # K33 to # K4 in the black nozzle row are used.
No. 5 is used, but when the print medium is a film-based print medium, the nozzles # K36 to # K48 are used. The nozzle # K36 is not shown.

As described above, when the print medium is a film type print medium, the black nozzles on the upstream side are used as compared with the case where the print medium is plain paper, so the cyan nozzles on the downstream side of the black nozzles are used. You can do a lot. As described above, the present embodiment has an advantage that the number of color dots formed by overlapping at least a part of the black dots can be increased. The same effect can be obtained by shifting the color nozzles used to the downstream side in the sub-scanning direction.

D. Printing Process of Third Embodiment: FIG. 9 is an explanatory diagram showing a nozzle array on the lower surface of the print head 28 in the third embodiment of the present invention. The third embodiment is different from the above-described embodiments in that nozzle groups for ejecting inks of a plurality of colors are arranged on the print head 28 side by side in the main scanning direction. Each nozzle group has 48 nozzles.

In the third embodiment, when printing on a film type printing medium, only some of the nozzles on the upstream side are used for forming black dots, and one nozzle on the downstream side is used for forming color dots. Only the nozzle of the part is used. Specifically, in the black nozzle group, 24 nozzles on the upstream side of the 48 nozzles installed are used, and in the color nozzle group, the 48 nozzles installed are used. Twenty-four downstream nozzles are used. In this way, dots with poor fixability are formed with some nozzles on the upstream side, and dots with good fixability are formed with some nozzles on the downstream side, so that dots with good fixability have poor fixability. It can be formed by overlapping on the dots.

As described above, according to the present invention, printing is performed such that the nozzle group for ejecting the ink having the poor fixing property and the nozzle group for ejecting the ink having the good fixing property are arranged at the same position in the sub-scanning direction. It can be seen that it can be applied to printing using a head.

The reason why the above printing is performed only on the film type printing medium is that the printing speed is lowered because the number of nozzles used for printing is reduced. In addition,
The number of nozzles used can be increased more than in this example. However, when the number of nozzles used is increased, the printing speed is increased, but the number of color dots formed over the black dots is reduced, so it is preferable to appropriately balance the two.

E. Color conversion table generation processing:
It is explanatory drawing which shows the relationship between RGB color space and CMY color space. The solid body shown in FIG. 10 has a C hue axis which is a coordinate axis from the vertex C to the vertex K, and the vertex M to the vertex K.
The M hue axis which is the coordinate axis leading to the vertex Y, the Y hue axis which is the coordinate axis extending from the apex Y to the vertex K, the R hue axis which is the coordinate axis extending from the vertex R to the vertex K, and the coordinate axis extending from the vertex G to the vertex K. It has a G hue axis, a B hue axis that is a coordinate axis from the vertex B to the vertex K, and an achromatic W hue axis that is a coordinate axis from the vertex W to the vertex K.

The RGB gradation data, which is the image to be printed, can be converted into C, M, and Y gradation data in accordance with such a relationship. The color conversion table LUT stores the data to be referred to in order to perform such color conversion.
Is. However, in this embodiment, since the printer 20 can also use black ink, the color conversion table LUT is
It also stores data for converting RGB gradation data into C, M, Y, and K gradation data. The K gradation data is generated by replacing a part of each of the C, M, and Y gradation values with the K gradation value.

The color conversion table LUT can be generated as follows, for example. First, the RGB image data on each hue axis other than the C hue axis and the print image are compared to experimentally generate the C, M, Y, and K tone data corresponding to the RGB tone data. Next, the color conversion table LUT can be generated by interpolating the data between the axes based on these data.

FIG. 11 is an explanatory diagram showing the relationship between the gray level and the dot recording rate on the W hue axis. Here, the dot recording rate refers to the ratio of the area of dots formed per unit area of the print medium. For example, if a total of 500 dots having an area of 0.001 square millimeters is formed in a certain area of 1 square millimeter, the dot recording rate in that area is 50%. In addition, in the present embodiment, the following assumptions are made in order to make the explanation easy to understand. (1) The C, M, Y, and K inks are ideal inks. (2) The ink duty limit value is 150%. Here, the ink duty means the total amount of ink dots formed per unit area, and 100% ink duty corresponds to the total amount of ink dots for filling all the pixels. (3) The size of the dot to be formed is only one kind of dot having a size to fill the pixel. As a result, the ink duty becomes equal to the dot recording rate. (4) Color conversion table LUT for film-based print media
Is M, Y in the area where the black dots are formed.
Is set so that the total dot recording rate is always 60% or more.

FIG. 11A is an explanatory diagram showing the relationship between the gray level and the dot recording rate when the color conversion table LUT for plain paper is used. As shown in this figure, until the gray level increases from 0% to A%, the C, M, and Y dot recording rates increase with the increase. Also, as you can see from the figure, in this area,
Dots are formed only with C, M, and Y inks. That is, in the low gray level region, the gray color is reproduced only by the composite black.

Until the gray level rises from A% to 100%, C, M and Y dots are gradually replaced by K dots. When the gray level reaches 100%, all the C, M, and Y dots are replaced with K dots, and the total of C, M, and Y dot recording rates is 0%. That is, in the high gray level region, the gray color is reproduced by decreasing the composite black and increasing the black dots.

FIG. 11B is an explanatory diagram showing the relationship between the gray level and the dot recording rate when the color conversion table LUT for the film type print medium is used. When a color conversion table LUT for a film-based print medium is used, C, M, and C in the area where the black dots are formed (gray level is A% to 100%).
The Y dot recording rate is always 90% or more. As a result, the M and Y dot recording rates can be set to 60% or more. On the other hand, since the ink duty limit is 150%, the K dot recording rate is adjusted to 60% or less. Color conversion data for the W hue axis is generated so that such a dot recording rate is realized.

Color conversion table L for film print media
The UT is generated by interpolating based on the data of each hue axis generated in this way. Then, the color conversion module 98 refers to this color conversion table LUT to convert the RGB image data, which is the image to be printed, into C, M, Y, and K gradation data usable in the printer 20. Perform conversion processing. As a result, M,
Since the Y dot recording rate is always 60% or more in the area where the K dots are formed, it is possible to improve the fixability of the ink on the film-based print medium.

F. Modifications: The present invention is not limited to the above-described embodiments and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are also possible. is there.

F-1. In each of the above-described embodiments, when printing on a film-based print medium, a dedicated color conversion table L is used.
Although the UT is selected, the same color conversion table LUT may be used regardless of the print medium. For example, by using a print head having a nozzle array as shown in FIG. Printing is performed so that the number of dots with good fixability formed by overlapping at least part of the dots with poor fixability is larger than the number of dots with good fixability formed under the dot with poor fixability. It may be performed.

F-2. In the above embodiment, the ink having poor fixability is black ink, but the ink having poor fixability may be cyan ink. In general, the present invention forms a group of nozzles for ejecting ink that forms dots that are relatively easy to peel from a specific print medium after drying, and dots that are relatively hard to peel from a specific print medium after drying. It can be applied to printing using a nozzle group for ejecting ink. When the ink having poor fixability is cyan ink, it is preferable to use nozzles on the downstream side of the nozzle group that ejects cyan ink, as shown in FIG.

F-3. In the above embodiment, the print head has a plurality of nozzle rows, but it may have a single nozzle row as shown in FIG.

F-4. In the above-described embodiment, when the print medium type is a film type print medium, the color conversion table LUT for the film type print medium is selected. However, the print medium type is resin data such as CD-R. Also in the case of a recording medium, such a color conversion table LUT may be selected.

F-5. In the above embodiment, the type of print medium is specified by selecting the print mode, but it may be specified by equipping the printing apparatus with means for automatically specifying the type of print medium. In general,
Any configuration may be used as long as information indicating the type of print medium is given.

As means for automatically specifying the type of print medium, for example, an optical specifying means for identifying and specifying reflected light based on a difference in light reflectance of special paper or plain paper, or a recording medium in advance. Bar code reading means for specifying by reading the bar code attached to the packaging material or its packaging material, I
There is a means to specify using the C reader. Such means has an advantage that no user operation is required to specify the type of print medium, and the means specified by selecting the print mode can be realized with a simple configuration.

F-6. The present invention can be applied to monochrome printing as well as color printing. For example, it can be applied to a printing apparatus that can use a pigment-based black ink and a dye-based black ink. It can also be applied to printing in which multiple gradations are expressed by expressing one pixel with a plurality of dots. It can also be applied to a drum printer. In addition,
In the drum printer, the drum rotation direction is the main scanning direction and the carriage traveling direction is the sub scanning direction. Further, the present invention can be applied not only to an ink jet printer, but also to a dot recording apparatus that generally records on a surface of a print medium using a recording head having a plurality of nozzle rows.

F-7. In the above embodiment, part of the configuration realized by hardware may be replaced with software, or conversely, part of the structure realized by software may be replaced with hardware. For example, some or all of the functions of the printer driver 96 shown in FIG.
Alternatively, the control circuit 40 therein may be executed.
In this case, the control circuit 40 of the printer 20 realizes some or all of the functions of the computer 90 as a print control device that creates print data.

When some or all of the functions of the present invention are implemented by software, the software (computer program) can be provided in a form stored in a computer-readable recording medium. In the present invention, "computer-readable recording medium"
The term is not limited to a portable recording medium such as a flexible disk or a CD-ROM, but includes an internal storage device in a computer such as various RAMs and ROMs, and an external storage device fixed to the computer such as a hard disk. I'm out.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a printing system as an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a color printer 20.

FIG. 3 is a side sectional view showing a sub-scan feed mechanism that conveys a print sheet P.

FIG. 4 is an explanatory diagram showing a nozzle array on the lower surface of the print head according to the first embodiment of the present invention.

FIG. 5 is a flowchart showing a procedure of printing processing according to the first embodiment of the present invention.

FIG. 6 is a view showing an example of a print mode basic setting screen displayed on the CRT 21.

FIG. 7 is an explanatory diagram showing a nozzle array on the lower surface of the print head according to the second embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a nozzle array on the lower surface of the print head according to the second embodiment of the present invention.

FIG. 9 is an explanatory diagram showing a nozzle array on the lower surface of the print head according to the third embodiment of the present invention.

FIG. 10 is an explanatory diagram showing an outline of a relationship between an RGB color space and a CMY color space.

FIG. 11 is an explanatory diagram showing a relationship between RGB gradation values and dot recording rates.

FIG. 12 is a print head according to a first modified example of the invention.
Explanatory diagram showing a nozzle array on the lower surface of FIG.

FIG. 13 is a print head according to a second modified example of the invention.
Explanatory diagram showing a nozzle array on the lower surface of FIG.

[Explanation of symbols]

20 ... Color printer 21 ... CRT 22 ... Paper feed motor 24 ... Carriage motor 25 ... Paper feed side sub-scan feed mechanism 26 ... Platen 27 ... Paper ejection side sub-scan feed mechanism 28 ... Print head 30 ... Carriage 32 ... Operation panel 34 ... Sliding shaft 36 ... Drive belt 38 ... pulley 39 ... Position sensor 40 ... Control circuit 56 ... Connector 60 ... Print head unit 90 ... Computer 91 ... Video driver 95 ... Application program 96 ... Printer driver 97 ... Resolution conversion module 98 ... Color conversion module 99 ... Halftone module 100 ... rasterizer 101 ... Print mode selection unit

Claims (19)

[Claims] 1. A print control apparatus for generating print data to be supplied to a print unit for performing printing by using a print unit that forms dots on a print medium while performing main scanning of a print head. The print head includes a first type nozzle group for ejecting a first type ink that forms a first type dot that is relatively easily separated from the print medium after drying, and the print medium after drying. A second type nozzle group for ejecting a second type ink that forms a second type dot that is relatively hard to peel off from the print target image data representing a print target image. A print data generation unit that generates print data including raster data indicating a dot recording state at each main scan and sub-scan feed data indicating a sub-scan feed amount performed between each main scan according to Equipped with Serial print data generating unit, the print data, the first
The printing is performed so that the number of the dots of the second type formed by overlapping from at least a part of the dots of the type one is larger than the number of the dots of the second type formed below the dot of the type one. A print control apparatus, wherein the print control apparatus is configured to generate a copy for printing. 2. The print control device according to claim 1, wherein the print data generation unit, when the print medium is a specific print medium, prints at least a part of the dots of the first type. The ratio of the dots of the second type that are overlapped with each other to the dots of the second type that are formed below the dots of the first type print on a print medium other than the specific print medium. A print control device that generates the print data so as to be larger than the case. 3. The print control device according to claim 2, wherein the print data generation unit outputs the print data to the first print data.
Regarding the kind of nozzle group, when printing on the specific print medium, nozzles located on the upstream side in the sub-scanning direction are used as compared with the case of printing on another print medium other than the specific print medium. A printing control device configured to perform printing by performing printing. 4. The print control device according to claim 2, wherein the print data generation unit stores the print data in the second print data.
Regarding the nozzle group of the kind, when printing on the specific print medium, nozzles located on the more downstream side in the sub-scanning direction are used than when printing on another print medium other than the specific print medium. A printing control device configured to perform printing by performing printing. 5. The print control device according to claim 2, wherein the print data generation unit is configured to print the image data to be printed from a first color system to ink used in the print head. A color conversion unit for converting into a second color system for the color conversion unit, the color conversion unit, when the print medium is a specific print medium, at least a part of the dots of the first type. The ratio of the dots of the second type formed by being overlapped from above to the dots of the second type formed below the dots of the first type is set to a value other than that of the specific print medium. A print control device that performs color conversion that is larger than when printing. 6. The print control device according to claim 5, wherein the color conversion unit includes a plurality of color conversion tables including a specific color conversion table for use when printing on the specific print medium. A color conversion table storage unit for storing the color conversion table; and a color conversion table selection unit for selecting the specific color conversion table when printing on the specific print medium. The second dot formed under the first type dot of the second type dots formed by overlapping at least a part of the one type dot
The ratio of the seeds to the dots is set to be larger than the color conversion tables other than the specific color conversion table,
Print control device. 7. The print control device according to claim 2, wherein the print control device is formed after the dots of the first type are formed at an arbitrary position of the print medium. A print control device for generating the print data such that a recording rate of the second type dots per unit area is higher than a predetermined rate. 8. The print control device according to claim 7, wherein: The print control device, wherein the predetermined ratio is 60%. 9. The print control device according to claim 2, wherein the specific print medium is a film-based print medium.
Print control device. 10. The print control device according to claim 2, wherein the print medium is a surface layer of a data recording medium made of resin. 11. The print control device according to claim 1, wherein the first type ink is an ink that uses a pigment as a coloring material. 12. The print control device according to claim 1, wherein the first type ink is black ink. 13. A printing apparatus that performs printing using a printing unit that forms ink dots on a printing medium while performing main scanning of a printing head, wherein the printing unit and any one of claims 1 to 12. And a printing control device according to claim 1. 14. A printing apparatus for performing printing by forming dots on a print medium while performing main scanning of the print head, wherein the print head is relatively easily peeled off from the print medium after drying. A first type nozzle group for ejecting a first type ink that forms one type of dot, and a second type ink that forms a second type dot that is relatively difficult to peel off from the print medium after drying A second type nozzle group for ejecting the second type dots, wherein the second type dots formed by overlapping from at least a part of the first type dots are the first type nozzle groups. Printing is performed so that the number of dots is larger than that of the second type dots formed below the first type dots.
Printing device. 15. The printing apparatus according to claim 14, wherein the first type nozzle group and the second type nozzle group are:
The number of nozzles belonging to the second type nozzle group arranged downstream in the sub-scanning direction from any nozzle belonging to the first type nozzle group is higher than that of any nozzle belonging to the first type nozzle group. Is also arranged so that the number of nozzles belonging to the second type nozzle group arranged upstream in the sub-scanning direction is larger. 16. A printing method for performing printing by forming dots on a print medium while performing main scanning of a print head, the first type being relatively easy to peel off from the print medium after (a) drying. Nozzle of the first type for ejecting the first type of ink that forms the dots of the second type, and the second type of ink that forms the dots of the second type that are relatively hard to peel off from the print medium after drying. Preparing a print head including a second type nozzle group for
The number of dots of the second type formed by overlapping from at least a part of the dots of the first type is larger than the number of the dots of the second type formed under the dots of the first type. A step of executing printing,
Printing method. 17. A print control method for generating print data to be supplied to a printing unit for performing printing using a printing unit that forms dots on a print medium while performing main scanning of a print head. , (A) forming a first type dot that is relatively easy to peel off from the print medium after drying,
A first type nozzle group for ejecting a second type ink, and a second type nozzle for ejecting a second type ink that forms dots of the second type that are relatively hard to peel off from the print medium after drying. A step of preparing a print head including a nozzle group; and (b) raster data indicating a dot recording state at each main scan and an interval between each main scan according to print target image data indicating a print target image. And a step of generating print data including sub-scan feed data representing a sub-scan feed amount to be performed, in the step (b), at least a part of the dots of the first type is included in the print data. A configuration in which the printing unit executes printing so that the number of dots of the second type formed by overlapping from above is larger than the number of dots of the second type formed below the dots of the first type Including the step of producing to have A printing control method characterized by: 18. A computer program for causing a computer to generate print data to be supplied to the printing unit in order to perform printing by using a printing unit that forms dots on a printing medium while performing main scanning of the printing head. The print head includes a first type nozzle group for ejecting a first type ink that forms a first type dot that is relatively easily peeled off from the print medium after drying, and a first type nozzle group after drying. A second type nozzle group for ejecting a second type ink that forms a second type dot that is relatively hard to peel off from the print medium, and the computer program is a print target representing an image to be printed. Depending on the image data, it includes raster data indicating a dot recording state during each main scan, and sub-scan feed data indicating a sub-scan feed amount performed between each main scan. A program for causing the computer to realize a function of generating printing data, wherein the function is that the second type dot formed by overlapping the print data from at least a part of the first type dot is formed. And a function to generate so that the number of dots of the second type formed below the dots of the first type is greater than that of the dots of the second type. Computer program. 19. A computer-readable recording medium in which the computer program according to claim 18 is recorded.