JP2008162248A - Printing device, printing device control program, printing device control method, image processor, image processing program, and image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing device for printing an image by ejecting liquid ink, in which the printing device is fitted for preventing a cockling phenomenon, a curling phenomenon, etc., and to provide a printing device control program, a printing device control method, an image processor, an image processing program, and an image processing method. <P>SOLUTION: The printing device 1 comprises: a printing image data acquiring section 10 for acquiring printing image data; a rendering processing section 12 for rendering processing the printing image data having image information generated from a page describing language; a printing concentration modification section 14 for modifying a printing concentration of an image of the printing image data after the rendering processing; an N-th order digitization section 16 for carrying out N-th order digitization of the printing image data; and a printing section 18 for printing an image, based on the printing image data on which the N-th order digitization is carried out. Herein in the printing concentration modification section 14, modification is carried out such that the printing concentration of an image in a character region is higher than the printing concentration of an image in a region other than the character region. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a printing apparatus, a printing apparatus control program, and a printing apparatus control method used for a facsimile apparatus, a copying machine, a printing apparatus for office automation equipment, and the like. ) It was designed to draw on top of the characters and images
The present invention relates to a printing apparatus, a printing apparatus control program, a printing apparatus control method, an image processing apparatus, an image processing program, and an image processing method suitable for performing a so-called inkjet printing process.

The following describes a printing apparatus, particularly a printer that employs an inkjet method (hereinafter referred to as an “inkjet printer”).
Ink jet printers are generally inexpensive and can easily obtain high-quality color prints, and are widely used not only in offices but also in general users with the spread of personal computers and digital cameras.

In such an ink jet printer, generally, a moving body called a carriage having an ink cartridge and a print head integrally provided on a print medium (paper) in a direction perpendicular to the paper feed direction. By ejecting (injecting) liquid ink particles in the form of dots from the nozzles of the print head while reciprocating, predetermined characters and images are drawn on the print medium to create a desired printed matter. The carriage is equipped with ink cartridges of four colors (black, yellow, magenta, cyan) including black (black) and a print head for each color, so that not only monochrome printing but also full-color printing combining each color is possible. (Furthermore, 6 colors, 7 colors, or 8 colors in which light cyan, light magenta, etc. are added to these colors are also put into practical use).

As described above, since the ink jet printer performs printing by discharging liquid ink onto paper, the paper on which the ink is sprayed is in the same state as when the paper is wet with water. In particular, when a large amount of ink is sprayed, the paper surface of that portion undulates (referred to as a cockling phenomenon), and when the amount of ink sprayed increases over the entire paper, the entire paper curls into a cylindrical shape (curl phenomenon) Phenomenon). These phenomena occur particularly when water-based ink is used. In order to prevent these phenomena from occurring, conventionally, a maximum ink discharge amount (maximum print density) per predetermined area is determined in advance so that the above phenomenon does not occur, and the determined maximum ink discharge amount is determined. The printing process is controlled so that the ink is discharged within the limit.

However, if such printing process control is performed, the same maximum ink discharge amount is applied to all the image elements constituting the image. Therefore, image elements such as characters and image elements other than characters The print density difference between the print area and the character image area is low, and print results with sufficient contrast cannot be obtained for the character image area. That is, since the maximum ink discharge amount of the image element of a character with a low printing density and the solid image portion with a high printing density are the same, the character portion may be blurred.

In order to solve the above problem, an ink jet recording apparatus described in Patent Document 1 has been proposed.
This inkjet recording apparatus calculates the area of a figure to be drawn, compares the calculation result with a preset threshold value, compares the figure density included in the drawing command with a preset threshold value, When both exceed the threshold value, the maximum density of the figure is converted.
JP 2002-187266 A

However, in the prior art disclosed in Patent Document 1, it is necessary to calculate the area of a figure for each image, compare the calculation result with a threshold value, and perform processing for comparing the density of the figure with the threshold value. There is a risk of problems in terms of processing speed.
Therefore, the present invention has been made paying attention to such an unsolved problem of the conventional technology, and in a printing apparatus that discharges liquid ink to print an image, a cockling phenomenon, a curling phenomenon, etc. It is an object of the present invention to provide a printing apparatus, a printing apparatus control program, and a printing apparatus control method, and an image processing apparatus, an image processing program, and an image processing method that are suitable for suppressing the occurrence of the above.

[Mode 1] In order to achieve the above object, a printing apparatus according to mode 1 includes:
A print head having nozzles for printing dots by discharging ink onto a medium used for printing;
Printing image data acquisition means for acquiring printing image data having image information of gradation number M (M is a natural number of M ≧ 2);
The image of the image data for printing is based on information indicating the type of image element constituting the image of the image data for printing and print density information which is information on the print density preset for each type of the image element. Print density changing means for changing the print density of
Printing means for printing the image on the medium by the print head based on the print image data after changing the print density;
The print density information is information in which the maximum print density of the image element whose type belongs to a character is set to a print density higher than the maximum print density of an image element whose type belongs to other than a character. To do.

With such a configuration, the number of gradations M (M is M ≧ M) by the printing image data acquisition unit.
Printing image data having image information of (natural number of 2) can be obtained, and information indicating the types of image elements constituting the image of the printing image data by the print density changing means, and the type The maximum print density of the image element belonging to the character is set to a print density higher than the maximum print density of the image element whose type is other than the character, and the print density information set for each type of the image element. The print density of the image of the print image data can be changed based on the print image data, and the print head prints the image on the medium based on the print image data after the print density is changed. Is possible.

Accordingly, it is possible to change the print density of the image element belonging to the character based on the maximum print density higher than that of the image element other than the character. As a result, the print density of the image in the character area is
Since the print density of the image in other areas can be set to a relatively high density, the contrast between the image in the character area and the image in the other area in the image is clear (characters can be clearly seen). The effect that a printed image can be obtained is obtained.

Further, based on the information indicating the type of the image element, it is possible to change the print density of the image of the image data for printing based on the print density information set in advance for each type of the image element.
The print density can be changed by a very simple process. Therefore, it is also possible to execute the print density changing process with almost no increase in the time required for the print process.

Here, the dot refers to one region formed by ink ejected from one or a plurality of nozzles landing on a print medium. Further, “dots” are not “zero” in area, and of course have a certain size (area), and there are a plurality of types for each size. However, dots formed by ejecting ink are not always perfect circles. For example, when dots are formed in a shape other than a perfect circle such as an ellipse, the average diameter is treated as the dot diameter, or the area equal to the area of the dots formed by ejecting a certain amount of ink is used. In some cases, a perfect circle equivalent dot is assumed and the diameter of the equivalent dot is treated as the dot diameter. Also,
Examples of the method of placing dots having different densities include, for example, a method of hitting dots having the same dot size and different densities, a method of hitting dots having the same density and different sizes, and a discharge density of ink having the same density. It is possible to consider a method in which the dots are different and the density is varied by overstrike. In addition, when one ink droplet ejected from one nozzle is separated and landed, it is considered as one dot, but two nozzles or two or more formed from one nozzle around the time. If two dots are stuck, it is assumed that two dots are formed. Hereinafter, a form related to “printing apparatus”, a form related to “printing apparatus control program”, a form related to “printing apparatus control method”, a form related to “image processing apparatus”, a form related to “image processing program”, and a form related to “image processing method” , As well as the description relating to the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

The printing image data corresponds to character information, image information, palette information of characters and images, document data composed of position information of documents and images, image data composed of information of only images, and the like. . As document data, in addition to document data created by word processing software, document data generated by a page description language such as Postscript, XPS (X
Document data created by ML Paper Specification is included. A form relating to a printing apparatus control program, a form relating to a printing apparatus control method, a form relating to an image processing apparatus, a form relating to an image processing program, a form relating to an image processing method, a form relating to a computer-readable recording medium storing the program, and an invention It is the same in the column of the best mode for carrying out.

The printing image data acquisition means acquires printing image data input from an optical reading means such as a scanner means, or print data stored in an external device via a network such as a LAN or WAN. Image data can be acquired passively or actively, or a CD-ROM, DVD-R can be obtained via a drive device such as a CD drive or DVD drive of the printing device.
Printing image data is acquired from a recording medium such as an OM, printing image data stored in a storage device included in the image processing apparatus is acquired, and the like. That is, the acquisition includes at least input, acquisition, reception, and reading. A form relating to a printing apparatus control program, a form relating to a printing apparatus control method, a form relating to an image processing apparatus, a form relating to an image processing program, a form relating to an image processing method, a form relating to a computer-readable recording medium storing the program, and an invention It is the same in the column of the best mode for carrying out.

Further, the print density changing means includes density information of the printing image data having the gradation number M, density information after rendering the printing image data, density information after color conversion processing of the printing image data, and the like. It is possible to change the print density by changing the density information of the printing image data at the stage. Hereinafter, a form related to “printing apparatus”, a form related to “printing apparatus control program”, a form related to “printing apparatus control method”, a form related to “image processing apparatus”, a form related to “image processing program”, and a form related to “image processing method” , As well as the description relating to the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

The information indicating the type of image element is information that can be used to understand the type of image element that constitutes the image to be printed, such as a character image area or a graphic image area, and is included in the print image data. Information or information that can be separately obtained from a printer driver or the like. Less than,
A form relating to “printing apparatus”, a form relating to “printing apparatus control program”, a form relating to “printing apparatus control method”, a form relating to “image processing apparatus”, a form relating to “image processing program”, a form relating to “image processing method”, and The same applies to the description of the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

[Mode 2] Further, the printing apparatus of mode 2 is the printing apparatus of mode 1,
The print density changing unit is configured to change the print image data based on the print density information and the background density when the image of the print image data includes an image element belonging to a character whose type has a background. The printing density of the image element portion belonging to the character having the background in the image is changed.

With such a configuration, in addition to the effect of the first aspect, it is possible to change the print density in the density range in which the maximum print density is lower than the character-only area, for example, in the character area image having the background. Therefore, even for an image with a background in the character area, the contrast between the character area in the image and the image in the other area is clear (the character It is possible to obtain a printed image that can be clearly seen).

[Mode 3] Furthermore, the printing apparatus of mode 3 is the printing apparatus of mode 1 or 2,
The print density information is a color conversion information table used for color conversion processing of the image data for printing set for each type of the image element,
The print density changing means changes the print density of the image of the print image data based on the color conversion information table during color conversion processing for the print image data.

With such a configuration, it is possible to change the print density of the image of the print image data during the color conversion process of the print image data. For example, a look-up table (color conversion information) used for color conversion processing is converted into a character image look-up table 1 (LUT1).
And a look-up table 2 (LUT2) for other images, color conversion processing is performed using LUT1 for color conversion processing of character image regions, and color conversion of image regions other than character images is performed. For the processing, color conversion processing is performed using LUT2. That is, the color space including a density range higher than the density range of LUT2 is set in LUT1 so that the maximum print density can be higher than that of LUT2.

Therefore, by performing the color conversion process, the print density can be changed at the same time as the color conversion. Therefore, the print density change process can be executed at a higher speed. As a result, in addition to the above-described effect of the first or second aspect, the contrast between the character region and the other region in the image is clear (the character can be clearly seen) without substantially increasing the time required for the printing process. The effect that an image can be obtained is obtained.

[Form 4] Furthermore, the printing apparatus of form 4 is the printing apparatus of form 1 or 2,
The printing density changing means executes the printing density changing process on the printing image data before color conversion processing of the printing image data.
With such a configuration, it is possible to execute a print density change process on the print image data before the color conversion process. For example, R (Red) / G (Green)
In the image of the printing image data having B (Blue) color information, the R ·
The print density can be changed by changing the density information of G and B based on the maximum density information of each image element.

Accordingly, since the print density changing process can be easily executed, the print density changing process can be executed at a higher speed. As a result, in addition to the above-described effect of the first or second aspect, the contrast between the character region and the other region in the image is clear (the character can be clearly seen) without substantially increasing the time required for the printing process. The effect that an image can be obtained is obtained.

[Form 5] Furthermore, the printing apparatus of form 5 is the printing apparatus of form 1 or 2,
The print density changing means executes the print density changing process on the print image data after the color conversion process of the print image data.
With such a configuration, it is possible to execute a print density change process on the print image data after the color conversion process, and for example, R (Red) · G (Green)
) And B (Blue) color image data for printing are represented by C (Cyan) and M (Mag).
The density information of C, M, Y, and K of each pixel after conversion into print image data having color information of (enta), Y (Yellow), and K (Black) is used as the maximum density information of each image element. By changing based on the print density, it is possible to change the print density.
Therefore, in addition to the effect of the first or second aspect, the print density changing process can be executed for the color space to be printed, and the effect that the print density can be changed more accurately is obtained.

[Mode 6] Furthermore, the printing apparatus of mode 6 is the printing apparatus of mode 1 or 2,
The print density information is a process of converting image information of the number of gradations M of the print image data set for each type of image element into image information of the number of gradations N (M ≧ N ≧ 2). It is threshold information used for a certain N-value process,
The print density changing unit is configured to change a print density of an image of the print image data based on the threshold information during an N-value process for the print image data.

With such a configuration, for example, the image element belonging to the character has a higher dot generation probability (or a relatively large diameter dot generation probability) than the other image elements.
By setting a threshold value for N-value processing (also referred to as halftone processing) such as a dither matrix threshold value in advance, processing for changing the print density of the image data for printing is executed simultaneously with the N-value processing. Is possible.

Accordingly, the print density changing process can be executed at a higher speed.
In addition to the effect of the first or second aspect described above, a print image in which the contrast between the character region and the other region in the image is clear (the character can be clearly seen) is obtained without substantially increasing the time required for the printing process. The effect that it can be obtained.
[Mode 7] Further, the printing apparatus of mode 7 is the printing apparatus of mode 1 or 2,
The printing density changing means executes the printing density changing process on the printing image data during the rendering process of the printing image data.

With such a configuration, at the time of rendering processing, it is possible to execute processing for determining the type of each image element in the printing image data and processing for changing the print density.
Therefore, since the processing can be executed in the rendering module, in addition to the effect of the first or second aspect, the character region in the image can be obtained without substantially increasing the time required for the printing processing. An effect is obtained that a printed image having a clear contrast with other regions (characters can be clearly seen) can be obtained.

[Mode 8] On the other hand, in order to achieve the above object, a printing apparatus control program according to mode 8
A printing apparatus control program for controlling a printing apparatus having a print head having a nozzle for ejecting ink onto a medium used for printing to print dots,
A printing image data acquisition step of acquiring printing image data having image information of the number of gradations M (M is a natural number of M ≧ 2);
The image of the image data for printing is based on information indicating the type of image element constituting the image of the image data for printing and print density information which is information on the print density preset for each type of the image element. A print density change step for changing the print density,
Including a program used to cause a computer to execute a process including a printing step of printing the image on the medium by the print head based on the print image data after changing the print density,
The print density information is information in which the maximum print density of the image element whose type belongs to a character is set to a print density higher than the maximum print density of an image element whose type belongs to other than a character. To do.
With such a configuration, when the program is read by the computer and the computer executes processing in accordance with the read program, the same operations and effects as those of the printing apparatus of mode 1 can be obtained.

[Mode 9] Furthermore, the printing apparatus control program according to mode 9 is the same as the printing apparatus control program according to mode 8.
In the printing density changing step, when the image of the printing image data includes an image element belonging to a character whose type has a background, the printing image data is changed based on the printing density information and the density of the background. The printing density of the image element portion belonging to the character having the background in the image is changed.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operations and effects as those of the printing apparatus of mode 2 can be obtained.

[Mode 10] Furthermore, the printing apparatus control program according to mode 10 is the printing apparatus control program according to mode 8 or 9,
The print density information is a color conversion information table used for color conversion processing of the image data for printing set for each type of the image element,
The printing density changing step is performed during color conversion processing for the printing image data.
The printing density of the image of the printing image data is changed based on the color conversion information table.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operation and effect as those of the printing apparatus according to mode 3 can be obtained.

[Mode 11] Furthermore, the printing apparatus control program according to mode 11 is the printing apparatus control program according to mode 8 or 9,
In the printing density changing step, the printing density changing process is executed on the printing image data before the color conversion process of the printing image data.
With such a configuration, when the program is read by the computer and the computer executes processing in accordance with the read program, the same operation and effect as those of the printing apparatus of mode 4 can be obtained.

[Mode 12] Further, the printing apparatus control program according to mode 12 is the printing apparatus control program according to mode 8 or 9,
In the printing density changing step, the printing density changing process is executed on the printing image data after the color conversion processing of the printing image data.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operations and effects as those of the printing apparatus of mode 5 are obtained.

[Mode 13] Furthermore, the printing apparatus control program according to mode 13 is the printing apparatus control program according to mode 8 or 9,
The print density information is a process of converting image information of the number of gradations M of the print image data set for each type of image element into image information of the number of gradations N (M ≧ N ≧ 2). It is threshold information used for a certain N-value process,
In the print density changing step, the N-value conversion process is performed on the print image data.
The printing density of the image of the printing image data is changed based on the threshold information.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operations and effects as those of the printing apparatus of mode 6 are obtained.

[Form 14] Furthermore, the printing apparatus control program of aspect 14 is the printing apparatus control program of aspect 8 or 9,
In the printing density changing step, the printing density changing process is executed on the printing image data during the rendering process of the printing image data.
With such a configuration, when the program is read by the computer and the computer executes processing in accordance with the read program, the same operation and effect as those of the printing apparatus of mode 7 can be obtained.

[Mode 15] On the other hand, in order to achieve the above object, the printing medium control program according to any one of modes 8 to 14 is recorded on the recording medium of mode 15 so as to be readable by a computer.
As a result, the same operation and effect as the printing apparatus control program of any one of forms 8 to 14 can be obtained, and the printing apparatus control program can be executed via a recording medium such as a CD-ROM, DVD-ROM, or MO. It can be easily exchanged.

[Mode 16] In order to achieve the above object, a printing apparatus control method according to mode 16 includes:
A printing apparatus control method for controlling a printing apparatus having a print head having a nozzle for ejecting ink onto a medium used for printing to print dots,
A printing image data acquisition step of acquiring printing image data having image information of the number of gradations M (M is a natural number of M ≧ 2);
The image of the image data for printing is based on information indicating the type of image element constituting the image of the image data for printing and print density information which is information on the print density preset for each type of the image element. A print density change step for changing the print density,
A printing step of printing the image on the medium by the print head based on the print image data after changing the print density,
The print density information is information in which the maximum print density of the image element whose type belongs to a character is set to a print density higher than the maximum print density of an image element whose type belongs to other than a character. To do.
As a result, the same effect as that of the printing apparatus of aspect 1 can be obtained.

[Mode 17] Further, the printing device control method of mode 17 is the same as the printing device control method of mode 16.
In the printing density changing step, when the image of the printing image data includes an image element belonging to a character whose type has a background, the printing image data is changed based on the printing density information and the density of the background. The printing density of the image element portion belonging to the character having the background in the image is changed.
As a result, the same effect as that of the printing apparatus of aspect 2 is obtained.

[Form 18] Furthermore, the printing apparatus control method of aspect 18 is the same as the printing apparatus control method of aspect 16 or 17,
The print density information is a color conversion information table used for color conversion processing of the image data for printing set for each type of the image element,
The printing density changing step is performed during color conversion processing for the printing image data.
The printing density of the image of the printing image data is changed based on the color conversion information table.
As a result, an effect equivalent to that of the printing apparatus of mode 3 is obtained.

[Form 19] Furthermore, the printing apparatus control method of aspect 19 is the same as the printing apparatus control method of aspect 16 or 17,
In the printing density changing step, the printing density changing process is executed on the printing image data before the color conversion process of the printing image data.
As a result, the same effect as that of the printing apparatus of aspect 4 is obtained.

[Mode 20] Furthermore, the printing apparatus control method according to mode 20 is the printing apparatus control method according to mode 16 or 17,
In the printing density changing step, the printing density changing process is executed on the printing image data after the color conversion processing of the printing image data.
As a result, the same effect as that of the printing apparatus of mode 5 can be obtained.

[Mode 21] Furthermore, the printing device control method of mode 21 is the same as the printing device control method of mode 16 or 17,
The print density information is a process of converting image information of the number of gradations M of the print image data set for each type of image element into image information of the number of gradations N (M ≧ N ≧ 2). It is threshold information used for a certain N-value process,
In the print density changing step, the N-value conversion process is performed on the print image data.
The printing density of the image of the printing image data is changed based on the threshold information.
Thereby, the same effect as that of the printing apparatus of mode 6 can be obtained.

[Mode 22] Further, the printing device control method of mode 22 is the printing device control method of mode 16 or 17,
In the printing density changing step, the printing density changing process is executed on the printing image data during the rendering process of the printing image data.
Thus, the same effect as that of the printing apparatus according to mode 7 can be obtained.

[Mode 23] On the other hand, in order to achieve the above object, an image processing apparatus according to mode 23
Printing image data acquisition means for acquiring printing image data having image information of gradation number M (M is a natural number of M ≧ 2);
The image of the image data for printing is based on information indicating the type of image element constituting the image of the image data for printing and print density information which is information on the print density preset for each type of the image element. Printing density changing means for changing the printing density of
The print density information is information in which the maximum print density of the image element whose type belongs to a character is set to a print density higher than the maximum print density of an image element whose type belongs to other than a character. To do.

With such a configuration, it is possible to obtain operations and effects equivalent to those of the printing apparatus of form 1, and for example, by simply sending the printing image data with the print density changed in this form to the printing apparatus, the printing Since it is possible to configure the apparatus so that the printing process can be executed, it is possible to use an existing inkjet printing apparatus as it is without preparing a dedicated printing apparatus. .
In addition, since a general-purpose information processing apparatus such as a PC (Personal Computer) can be used, an existing printing system including a print instruction apparatus such as a PC and an inkjet printer can be used as it is.

[Mode 24] Further, the image processing apparatus of mode 24 is the image processing apparatus of mode 23,
The print density changing unit is configured to change the print image data based on the print density information and the background density when the image of the print image data includes an image element belonging to a character whose type has a background. The printing density of the image element portion belonging to the character having the background in the image is changed.
As a result, the same operations and effects as those of the printing apparatus of aspect 2 can be obtained.

[Mode 25] Furthermore, the image processing apparatus of mode 25 is the image processing apparatus of mode 23 or 24,
The print density information is a color conversion information table used for color conversion processing of the image data for printing set for each type of the image element,
The print density changing means changes the print density of the image of the print image data based on the color conversion information table during color conversion processing for the print image data.
As a result, the same operations and effects as those of the printing apparatus of aspect 3 can be obtained.

[Mode 26] Furthermore, the image processing apparatus of mode 26 is the image processing apparatus of mode 23 or 24,
The printing density changing means executes the printing density changing process on the printing image data before color conversion processing of the printing image data.
Thereby, the same operation and effect as those of the printing apparatus of aspect 4 can be obtained.

[Mode 27] Furthermore, the image processing apparatus of mode 27 is the image processing apparatus of mode 23 or 24,
The print density changing means executes the print density changing process on the print image data after the color conversion process of the print image data.
As a result, the same operations and effects as those of the printing apparatus according to mode 5 can be obtained.

[Mode 28] Furthermore, the image processing apparatus of mode 28 is the image processing apparatus of mode 23 or 24,
The print density information is a process of converting image information of the number of gradations M of the print image data set for each type of image element into image information of the number of gradations N (M ≧ N ≧ 2). It is threshold information used for a certain N-value process,
The print density changing unit is configured to change a print density of an image of the print image data based on the threshold information during an N-value process for the print image data.
Thereby, the same operation and effect as those of the printing apparatus of mode 6 can be obtained.

[Mode 29] Further, the image processing apparatus of mode 29 is the image processing apparatus of mode 23 or 24,
The printing density changing means executes the printing density changing process on the printing image data during the rendering process of the printing image data.
As a result, the same operation and effect as those of the printing apparatus of aspect 7 can be obtained.

[Mode 30] On the other hand, in order to achieve the above object, an image processing program of mode 30
A printing image data acquisition step of acquiring printing image data having image information of the number of gradations M (M is a natural number of M ≧ 2);
The image of the image data for printing is based on information indicating the type of image element constituting the image of the image data for printing and print density information which is information on the print density preset for each type of the image element. A program used to cause a computer to execute a process having a print density change step for changing the print density of
The print density information is information in which the maximum print density of the image element whose type belongs to a character is set to a print density higher than the maximum print density of an image element whose type belongs to other than a character. To do.
With such a configuration, when the program is read by the computer and the computer executes processing in accordance with the read program, the same operations and effects as those of the printing apparatus of mode 1 can be obtained.

[Mode 31] Furthermore, the image processing program of mode 31 is the image processing program of mode 30,
In the printing density changing step, when the image of the printing image data includes an image element belonging to a character whose type has a background, the printing image data is changed based on the printing density information and the density of the background. The printing density of the image element portion belonging to the character having the background in the image is changed.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operations and effects as those of the printing apparatus of mode 2 can be obtained.

[Mode 32] Furthermore, the image processing program of mode 32 is the image processing program of mode 30 or 31,
The print density information is a color conversion information table used for color conversion processing of the image data for printing set for each type of the image element,
The printing density changing step is performed during color conversion processing for the printing image data.
The printing density of the image of the printing image data is changed based on the color conversion information table.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operation and effect as those of the printing apparatus according to mode 3 can be obtained.

[Mode 33] Furthermore, the image processing program of mode 33 is the image processing program of mode 30 or 31,
In the printing density changing step, the printing density changing process is executed on the printing image data before the color conversion process of the printing image data.
With such a configuration, when the program is read by the computer and the computer executes processing in accordance with the read program, the same operation and effect as those of the printing apparatus of mode 4 can be obtained.

[Form 34] Furthermore, the image processing program of form 34 is the image processing program of form 30 or 31,
In the printing density changing step, the printing density changing process is executed on the printing image data after the color conversion processing of the printing image data.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operations and effects as those of the printing apparatus of mode 5 are obtained.

[Mode 35] Furthermore, the image processing program of mode 35 is the image processing program of mode 30 or 31,
The print density information is a process of converting image information of the number of gradations M of the print image data set for each type of image element into image information of the number of gradations N (M ≧ N ≧ 2). It is threshold information used for a certain N-value process,
In the print density changing step, the N-value conversion process is performed on the print image data.
The printing density of the image of the printing image data is changed based on the threshold information.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operations and effects as those of the printing apparatus of mode 6 are obtained.

[Mode 36] Furthermore, the image processing program of mode 36 is the image processing program of mode 30 or 31,
In the printing density changing step, the printing density changing process is executed on the printing image data during the rendering process of the printing image data.
With such a configuration, when the program is read by the computer and the computer executes processing in accordance with the read program, the same operation and effect as those of the printing apparatus of mode 7 can be obtained.

[Mode 37] On the other hand, in order to achieve the above object, the image processing program according to any one of modes 30 to 36 is recorded on the recording medium of mode 37 so as to be readable by a computer.
As a result, the same operation and effect as the image processing program of any one of forms 30 to 36 can be obtained, and the image processing program can be easily obtained via a recording medium such as a CD-ROM, DVD-ROM, or MO. It is possible to give and receive.

[Mode 38] On the other hand, in order to achieve the above object, an image processing method according to mode 38 includes:
A printing image data acquisition step of acquiring printing image data having image information of the number of gradations M (M is a natural number of M ≧ 2);
The image of the image data for printing is based on information indicating the type of image element constituting the image of the image data for printing and print density information which is information on the print density preset for each type of the image element. A print density changing step for changing the print density of
The print density information is information in which the maximum print density of the image element whose type belongs to a character is set to a print density higher than the maximum print density of an image element whose type belongs to other than a character. To do.
As a result, the same effect as that of the printing apparatus of aspect 1 can be obtained.

[Mode 39] Furthermore, the image processing method of mode 39 is the same as the image processing method of mode 38,
In the printing density changing step, when the image of the printing image data includes an image element belonging to a character whose type has a background, the printing image data is changed based on the printing density information and the density of the background. The printing density of the image element portion belonging to the character having the background in the image is changed.
As a result, the same effect as that of the printing apparatus of aspect 2 is obtained.

[Form 40] Furthermore, the image processing method of form 40 is the image processing method of form 38 or 39,
The print density information is a color conversion information table used for color conversion processing of the image data for printing set for each type of the image element,
The printing density changing step is performed during color conversion processing for the printing image data.
The printing density of the image of the printing image data is changed based on the color conversion information table.
As a result, an effect equivalent to that of the printing apparatus of mode 3 is obtained.

[Form 41] Furthermore, the image processing method of form 41 is the same as the image processing method of form 38 or 39,
In the printing density changing step, the printing density changing process is executed on the printing image data before the color conversion process of the printing image data.
As a result, the same effect as that of the printing apparatus of aspect 4 is obtained.

[Form 42] Furthermore, the image processing method of form 42 is the image processing method of form 38 or 39,
In the printing density changing step, the printing density changing process is executed on the printing image data after the color conversion processing of the printing image data.
As a result, the same effect as that of the printing apparatus of mode 5 can be obtained.

[Form 43] Furthermore, the image processing method of form 43 is the image processing method of form 38 or 39,
The print density information is a process of converting image information of the number of gradations M of the print image data set for each type of image element into image information of the number of gradations N (M ≧ N ≧ 2). It is threshold information used for a certain N-value process,
In the print density changing step, the N-value conversion process is performed on the print image data.
The printing density of the image of the printing image data is changed based on the threshold information.
Thereby, the same effect as that of the printing apparatus of mode 6 can be obtained.

[Form 44] Furthermore, the image processing method of form 44 is the same as the image processing method of form 38 or 39,
In the printing density changing step, the printing density changing process is executed on the printing image data during the rendering process of the printing image data.
Thus, the same effect as that of the printing apparatus according to mode 7 can be obtained.

[First Embodiment]
A first embodiment of the present invention will be described below with reference to the drawings. 1 to 11 are diagrams illustrating a first embodiment of a printing apparatus, a printing apparatus control program and a printing apparatus control method, and an image processing apparatus, an image processing program, and an image processing method according to the present invention.
First, the configuration of the printing apparatus according to the first embodiment of the present invention will be described with reference to FIG. FIG.
1 is a block diagram illustrating a configuration of a printing apparatus 1 according to a first embodiment.

As shown in FIG. 1, the printing apparatus 1 includes a printing image data acquisition unit 10 that acquires printing image data having image information having a gradation number M (M ≧ 2) from an external device, a storage device, and the like, and a page A rendering processing unit 12 for rendering image data for printing having image information generated from a description language or the like, a printing density changing unit 14 for changing the printing density of the image data for printing after rendering processing, and for printing N-value processing unit 1 that performs N-value processing on image data
6 and a printing unit 18 that prints an image based on image data for printing that has been subjected to N-ary processing.

The print image data acquisition unit 10 has, for example, multi-gradation image information in which a gradation (luminance value) for each color (R, G, B) per pixel is expressed by 8 bits (0 to 255). It has a function of acquiring image data for printing. Image data for printing is acquired from an external device via a network in response to a print instruction from an external device such as a PC and an input device provided in the self-printing device, or a CD drive or DVD (not shown) provided in the self-printing device. It can be acquired from a recording medium such as a CD-ROM or DVD-ROM via a drive device such as a drive, or can be acquired from a storage device 70 described later provided in the self-printing device. In the present embodiment, the acquired print image data includes print information generated by the printer driver. In general, print information generated by a printer driver includes information about image elements constituting an image to be printed (hereinafter referred to as image element information) in addition to print setting information related to print settings. The image element information includes the type of each image element constituting the image,
Information such as shape, coordinates, and size is included.

When the print image data is document image data created in a page description language such as Postscript, the rendering processing unit 12 converts the information about the object or figure given as numerical data into an image by calculation (bit Mapping) (hereinafter, this processing is referred to as rendering processing). Further, each piece of pixel data when converted to a bitmap is associated with information indicating the type of image element of the pixel data.

The print density changing unit 14 includes image elements belonging to characters in the image of the print image data,
Image data for printing having color information other than CMYK color information, such as RGB color information, prepared in advance for image elements belonging to other than characters and based on two types of color conversion information having different density ranges. The color information is converted into CMYK color information. Here, in the present embodiment, the color information conversion process also serves as a print density change process.

When the image information included in the print image data is data expressed by the number of gradations M (for example, CMYK data having the number of gradations 256), the N-value conversion processing unit 16 It has a function of executing an N-value conversion process for converting image information into image information having a gradation number N.
Here, the print head 200 applied to the present invention will be described.
FIG. 2 is a partially enlarged bottom view showing the structure of the print head 200.

As shown in FIG. 2, the print head 200 has a long structure extending in the paper width direction of printing paper used in a so-called line head type printer, and has a plurality of nozzles N that eject black (K) ink exclusively. Black nozzle modules 50 arranged in a straight line (18 in the figure), a plurality of nozzles N for discharging yellow (Y) ink exclusively, and a yellow nozzle module 52 arranged in a straight line in the same direction; A plurality of nozzles N that eject magenta (M) ink exclusively, and a magenta nozzle module 54 arranged in a straight line in the same direction, and a plurality of nozzles N that eject cyan (C) ink in the same direction. Four nozzle modules 50, 52, 54, 56 such as cyan nozzle modules 56 arranged in a straight line are arranged in the printing direction (with respect to the nozzle arrangement direction). Which are arranged integrally so as to overlap in multiple stages in a straight direction (strictly dot printing direction of the nozzle)). In the case of a print head intended for monochrome, only black (K) is used. In the case of a print head targeted for a high-quality image, ink of 6 colors or 7 colors including light magenta or light cyan is added. Sometimes used.

Further, the print head 200 having such a structure is provided with a piezo (not shown) provided for each of the ink chambers. The ink supplied into the ink chamber (not shown) provided for each of the nozzles N1, N2, N3. By ejecting from each nozzle N1, N2, N3... By a piezoelectric element such as a piezo actuator, circular dots are printed on white printing paper, and the voltage applied to this piezoelectric element is multistage. By controlling the discharge amount of ink from the ink chamber, each nozzle N1, N2
, N3... Can be printed with dots of different sizes.

Returning to FIG. 1, the printing unit 18 includes the nozzle modules 50, 52 formed on the print head 200 while moving one or both of a medium (for example, printing paper) and / or the print head 200 used for printing. Ink jet printers configured to form a predetermined image composed of a large number of dots on a medium used for printing (hereinafter referred to as a print medium) by ejecting ink from dots 54 and 56 respectively. In addition to the print head 200, the print head feeding mechanism (not shown) that reciprocates the print head 200 in the width direction on the print medium (in the case of the multi-pass type), the paper feed (not shown) for moving the print medium. Mechanism, a print controller mechanism (not shown) that controls the ejection of ink from the print head 200 based on the print data, etc. And a known components.

Further, a detailed configuration of the print density changing unit 14 will be described with reference to FIGS. 3 and 4. here,
FIG. 3 is a block diagram showing a detailed configuration of the print density changing unit 14. FIG. 4 is a block diagram illustrating a detailed configuration of the color conversion unit 142.
The print density changing unit 14 includes a density control unit 140 and a color conversion unit 142, as shown in FIG.

When the density control unit 140 obtains the printing image data after the rendering process from the rendering processing unit 12, the pixel data that has not been subjected to the printing density change process in the printing image data and the image element corresponding to the pixel data It has a function of selecting information and determining whether the pixel data to be processed is pixel data of an image belonging to a character or other pixel data from the selected image element information. Further, based on the determination result, a first switching unit 14 to be described later.
Control information for controlling the switching process of 2a and the second switching unit 142d is generated, and the information is output to the color conversion unit 142 together with the selected pixel data.

Here, the control information is generated by either the first control information when the selected pixel data belongs to a character or the second control information when the selected pixel data belongs other than a character. And output.
As shown in FIG. 4, the color conversion unit 142 includes a first switching unit 142a and a first color conversion unit 142b.
And a second color conversion unit 142c and a second switching unit 142d.

When the control information and the pixel data are input from the density control unit 140, the first switching unit 142a performs processing for converting the color information of the pixel data based on the control information, the first color conversion unit 142b, It has a function of switching to one of the second color conversion units 142c. Specifically, when the first control information is input from the density control unit 140, the first color conversion unit 142b.
When the second control information is input, the second color conversion unit 142c is switched.

The first color conversion unit 142b converts the RGB color information of the pixel data acquired via the first switching unit 142a into CMYK color information based on its own color conversion information (lookup table A). It has a function to do. Here, look-up table A (hereinafter referred to as LUT)
A) is a color conversion table for character images, and is a data table in which converted C, M, Y, and K gradation values for R, G, and B gradation values are registered.

The second color conversion unit 142c converts the RGB color information of the pixel data acquired via the first switching unit 142a into CMYK color information based on its own color conversion information (lookup table B). It has a function to do. Here, look-up table B (hereinafter referred to as LUT)
B) is a color conversion table for images other than characters, and is a data table in which the converted gradation values of C, M, Y, and K are registered for the gradation values of R, G, and B. is there.

Here, the LUTA has conversion information corresponding to a higher density color space than the LUTB. In addition, as described above, an image area (type of image element belongs to a character (
(Hereinafter referred to as a character area) is color-converted by LUTA, and an image area belonging to other than a character is LU
Since color conversion is performed with TB, a higher print density can be set in a character area than in a non-character area.

In response to the control information from the density control unit 140, the second switching unit 142d switches the other party who obtains the pixel data after color conversion to one of the first color conversion unit 142b and the second color conversion unit 142c. It has a function. Specifically, when the first control information is input from the density control unit 140, the first color conversion unit 142b is switched, and when the second control information is input, the second color conversion unit 142c is switched.

Further, the printing apparatus 1 includes the printing image data acquisition unit 10 and the rendering processing unit 12.
In order to realize the above functions in the print density changing unit 14, the N-value conversion processing unit 16, the printing unit 18 and the like on software, and executing software for controlling hardware necessary for realizing the above functions A computer system is provided. As shown in FIG. 5, the hardware configuration of this computer system includes a CPU (Central Processing Unit) 60, which is a central processing unit responsible for various controls and arithmetic processing, and a main storage device (Main Stor
age (RAM) 62 and a read only memory (ROM) 64, which is a read only memory (PCI) (Peripheral Component Interconnect)
t) Various internal and external buses consisting of buses and ISA (Industrial Standard Architecture) buses 6
8 and the bus 68 via an input / output interface (I / F) 66,
An external storage device 70 such as an HDD, an output device 72 such as a printing unit 18, a CRT, and an LCD monitor, an input device 7 such as an operation panel, a mouse, a keyboard, and a scanner
4 and a network cable L for communicating with a print instruction apparatus (not shown) or the like.

When the power is turned on, a system program such as BIOS stored in the ROM 64 or the like loads various dedicated computer programs stored in advance in the ROM 64 into the RAM 62, and the CPU 60 follows the instructions described in the program loaded in the RAM 62. However, the above-mentioned functions are realized on software by performing predetermined control and arithmetic processing using various resources.

Various dedicated computer programs are not limited to those stored in the ROM 64,
What is installed in the storage device 70 via a recording medium such as a CD-ROM, DVD-ROM, or flexible disk (FD), or what is installed in the storage device 70 via a communication network such as the Internet is stored in the RAM 62. You can load it.
Furthermore, the flow of printing processing in the printing apparatus 1 configured as described above will be described with reference to FIG. Here, FIG. 6 is a flowchart showing the printing process in the printing apparatus 1.

As shown in FIG. 6, the printing process first proceeds to step S100, where the printing image data acquisition unit 10 determines whether or not there is a printing instruction from a printing instruction terminal (not shown) such as a personal computer. If it is determined that there is (Yes), the process proceeds to step S102. If not (No), the determination process is repeated until there is a print instruction.
When the process proceeds to step S102, the print image data acquisition unit 10 acquires the print image data sent together with the print instruction from the print instruction terminal, and the process proceeds to step S104.

In step S104, the rendering processing unit 12 performs rendering processing on the image data for printing that needs to be rendered (for example, image data for printing having document image information created in a page description language) to generate an image. The data is converted into data, the image data for printing after the rendering process and the image element information corresponding to the image data are output to the print density changing unit 14, and the process proceeds to step S106.

In step S106, the printing density changing unit 14 changes the printing density of the image of the printing image data acquired from the rendering processing unit 12, and the process proceeds to step S108.
In step S108, the N-value conversion processing unit 16 executes N-value conversion processing on the image information of the number of gradations M in the print image data after the change of the print density, and the image information of the number of gradations M is stored in the gradation. The image information is converted into image information of the characteristic N, and the process proceeds to step S110. For example, the image information of the number of gradations M is converted into the image information of the number of gradations N using a dither matrix stored in the storage device 70.

In step S110, the printing unit 18 drives the print head 200 based on the print image data after the N-value conversion process to print the image of the print image data on a print medium, and the process ends.
Next, the operation of the present embodiment will be described with reference to FIGS.
Here, FIG. 7 is a diagram illustrating an example of an image printed without performing the print density changing process of the present invention. FIG. 8 is a flowchart showing the print density changing process of the present embodiment. FIG. 9 is a flowchart showing color conversion processing according to the present embodiment. Further, FIG.
) Is a schematic diagram illustrating an example of a color space of LUTA, and (b) is a schematic diagram illustrating an example of a color space of LUTB. FIG. 11 is a diagram illustrating a numerical example of color conversion processing. In addition, FIG.
2 (a) is a diagram showing an example of an image printed without performing the print density changing process of the present invention,
(B) is a figure which shows an example of the printing image which performed the printing density change process of this invention.

When the printing apparatus 1 receives a print instruction from a print instruction apparatus (not shown) or the like (step S10).
0 branch of “Yes”), the print image data acquisition unit 10 acquires the print image data corresponding to the received print instruction (step S102). Here, as shown in FIG. 7, it is assumed that the acquired print image of the print image data is composed of a character region and a region other than a character (hereinafter referred to as a graphic region). The acquired printing data is data created in a page description language, and the image information has RGB color information. Further, the image data for printing includes image element information which is information of each image element constituting the image.

Accordingly, when the rendering processing unit 12 acquires the printing image data from the printing image data acquisition unit 10, the rendering processing unit 12 performs a rendering process on the printing image data, and converts the data created in the page description language to Image data is generated (step S104). Then, the rendering processing unit 12 outputs the printing image data after the rendering processing and the image element information corresponding to the printing image data to the printing density changing unit 14.

On the other hand, when the print image data after rendering processing is input to the density control unit 140 (“Yes” in step S200), the print density changing unit 14 performs color conversion processing (from the print image data) ( The pixel data not yet processed in the print density changing process) and image element information for the pixel data are selected (step S202). Further, based on the selected image element information, it is determined whether or not the selected pixel data belongs to a character (step S204).
. Here, when the type of image element of the pixel data belongs to a character (“Yes” in step S204).
In step S206, the first control information is generated and output to the color conversion unit 142 together with the selected pixel data (step S206). On the other hand, when the type of the image element of the selected pixel data does not belong to a character ("No" branch in step S204), the second control information is generated, and together with the selected pixel data, the color conversion unit 142 (step S214)
).

When the control information and the pixel data are input, the color conversion unit 142 executes a color conversion process (
Step S208).
When the color conversion process is executed, the first switching unit 142a determines whether or not the input control information is the first control information (step S300). If it is the first control information (“Yes” branch in step S300), the first color conversion unit 142b is switched to change the pixel data into the first control information.
The data is output to the color conversion unit 142b.

When the pixel data is input, the first color conversion unit 142b converts the RGB color information of the pixel data into CMYK color information based on the LUTA (step S302).
On the other hand, when the input control information is the second control information (“No” branch in step S300), the first switching unit 142a switches to the second color conversion unit 142c, and the pixel data is changed to the second color.
The data is output to the color conversion unit 142c.

When the pixel data is input, the first color conversion unit 142c converts the RGB color information of the pixel data into CMYK color information based on the LUTB (step S304).
In this embodiment, by using LUTA, color conversion within the CMYK color space range as shown in FIG. 10A is possible, while using LUTB, FIG. Color conversion within the color space range of CMYK as shown in FIG. As can be seen by comparing the CMYK color space ranges shown in FIGS. 10 (a) and 10 (b),
LUTA allows color conversion to a wider color space range than LUTB. In addition, FIG.
In the color spaces of 0 (a) and (b), the area of the high-density color space is expanded as the range is expanded.

Therefore, by performing color conversion using LUTA, it is possible to set a print density higher than that of LUTB in the image of the print image data.
Here, the color conversion processing result between the character region and the region other than the character is as shown in FIG. 11, for example. FIG. 11 corresponds to printing image data having RGB color space information with gradation values of 0 to 100, and print density data of a character area after color conversion with respect to input density data;
This shows the relationship with the print density data other than the character area.

For example, when pixel data of R, G, and B density data values of R “10”, G “100”, and B “100” is input to the first color conversion unit 142b, this is converted using LUTA. When the color conversion is performed, the data is converted into data of C “0”, M “90”, and Y “90” as shown in FIG. On the other hand, when the same pixel data is color-converted using LUTB, as shown in FIG.
0 ", M" 45 ", and Y" 45 "data. The example shown in FIG. 11 is print density data after color conversion for some input densities.

The color space range is determined by experiments or the like. For example, printing is performed while changing the print density in the case of a character image and in the case of a solid image, and the maximum density value where no cockling phenomenon or curl phenomenon occurs is searched for each. Then, based on the searched maximum density value, CMY of the LUTA for character images and the LUTB for images other than characters.
The color space range of K is determined. Note that FIG. 11 is a very simple conversion example when it is assumed that RGB and CMY have a complementary color relationship for convenience, and actually includes a viewpoint of color matching.
It should be set so as to achieve the desired color reproduction.

When the color conversion is completed in the first color conversion unit 142b or the second color conversion unit 142c, the data after the color conversion is output to the second switching unit 142d. The output source is the second switching unit 142d.
Are switched based on the control information.
On the other hand, the print density changing unit 14 determines whether or not the color conversion process has been completed for all pixel data in the print image data to be processed, and determines that the color conversion process has been completed (" In the “Yes” branch), the color-converted print image data is output to the N-ary processing unit 16 (step S212), and a series of processes is terminated and the process returns to the original process.

If the color conversion process has not been completed for all pixel data (step S210).
In the “No” branch), the density control unit 140 selects unprocessed pixel data and image element information corresponding to the pixel data from the print image data after rendering processing (step S202), and the series The process is executed (steps S204 to S214).
When the print image data after the color conversion processing is input, the N-value conversion processing unit 16 performs N-value conversion processing (
Image information (data) of gradation number M in the print image data
Is converted into image information (data) having a gradation number N (M ≧ N ≧ 2) (step S108).

When the printing unit 18 acquires the image data for printing after the N-value conversion processing from the N-value conversion processing unit 16,
Based on the image data for printing, the print head 200 is used to form dots on the print medium,
An image is printed (step S110).
The printed result is as shown in FIG. 12B. Compared with FIG. 11A printed without performing the print density conversion processing of the present invention, the print density in the character area shows no particular difference between the two. Although the printing density in the graphic area is clearly shown in FIG. 12B, the printing result shown in FIG.
It can be seen that the overall density is lower than the printing result of (a). That is, FIG.
) Is a print image in which the contrast between the character region and the non-character region is high, and the character region portion can be clearly seen.

As described above, the printing apparatus 1 according to the present embodiment performs color conversion on the character area image in the image data for printing using the LUTA whose density upper limit value of the color space used for color conversion is higher than the LUTB. On the other hand, it is possible to perform color conversion using LUTB for an image in an area other than characters.
As a result, the image of the character area can be printed with a higher density than the image of the area other than the character area, so that the occurrence of cockling phenomenon and curling phenomenon is suppressed and the contrast is high (the character area is clearly defined). It is possible to obtain a printing result.

In actual inkjet printing, the maximum density that can be printed is limited by the graphic portion of FIG. 12A in order to prevent curling and cockling. Therefore, FIG.
(B) becomes thinner overall, and in particular, the character portion is in a situation where the contrast is lower than that of the image obtained in FIG.
In the first embodiment, the printing image data acquisition unit 10 corresponds to the printing image data acquisition unit of the form 1 or 23, and the rendering processing unit 12 and the print density changing unit 14 include:
Corresponding to the print density changing means of any one of Embodiments 1, 3, 23 and 25, the N-value conversion processing unit 16
The printing unit 18 corresponds to the printing unit of mode 1.

Moreover, in the said 1st Embodiment, step S100-S102 are the forms 8, 16
, 30 and 38, corresponding to the printing image data acquisition step, step S10
4 to S106 correspond to the print density changing step of any one of forms 8, 10, 16, 18, 30, 32, 38 and 40, and steps S108 to S110 correspond to the print steps of form 8 or 16. .

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to the drawings. 13 to 14 show a printing apparatus, a printing apparatus control program and a printing apparatus control method, and an image processing apparatus according to the present invention.
It is a figure which shows 2nd Embodiment of an image processing program and an image processing method.

Here, the printing apparatus according to the present embodiment has the same configuration as that of the printing apparatus 1 according to the first embodiment, and only the configuration of the color conversion unit in the print density changing unit 14 is different.
Hereinafter, only the parts different from the first embodiment will be described, and the description of the overlapping parts will be omitted.
Here, FIG. 13 is a block diagram showing a detailed configuration of the color conversion unit 142 in the present embodiment.

As shown in FIG. 13, the color conversion unit 142 includes a third color conversion unit 142e and a color conversion information storage unit 142f.
When the control information and the pixel data are input from the density control unit 140, the third color conversion unit 142e reads the LUTA or the LUTB from the color conversion information storage unit 142f based on the control information, and uses the read LUT. , The RGB color information of the input pixel data is CM
It has a function of color conversion to YK color information.

Specifically, when the first control information is input, the LUTA is read from the color conversion information storage unit 142f.
When the second control information is input, the LUTB is read from the color conversion information storage unit 142f and the color conversion process is executed.
Note that the LUTA and the LUTB have conversion information corresponding to a color space having a higher density than the LUTB, as in the first embodiment.

The color conversion information storage unit 142f has a function of storing the LUTA and the LUTB.
Next, the operation of the present embodiment will be described with reference to FIG.
Here, FIG. 14 is a flowchart showing the color conversion processing of the color conversion unit 142 of the present embodiment.

Since the process up to the control information output process is the same as that of the first embodiment, the operation from the color conversion process will be described below.
When the control information and the pixel data are input, the color conversion unit 142 executes a color conversion process (
Step S208).
When the color conversion process is executed, the third color conversion unit 142e determines whether or not the input control information is the first control information (step S400). If it is the first control information (“Yes” branch of step S400), the LUTA is read out and acquired from the color conversion information storage unit 142f (step S402), and the input is made based on the acquired LUTA. The RGB color information of the pixel data is converted into CMYK color information (step S404).

On the other hand, when the input control information is the second control information (“No” branch in step S400), the third color conversion unit 142e reads and acquires the LUTB from the color conversion information storage unit 142f (step S400). S406) Based on the acquired LUTB, the RGB color information of the input pixel data is converted into CMYK color information (step S404).
On the other hand, the print density changing unit 14 determines whether or not the color conversion process has been completed for all pixel data in the print image data to be processed, and determines that the color conversion process has been completed (" In the “Yes” branch), the color-converted print image data is output to the N-ary processing unit 16 (step S212), and a series of processes is terminated and the process returns to the original process.

If the color conversion process has not been completed for all pixel data (step S210).
In the “No” branch), the density control unit 140 selects unprocessed pixel data and image element information corresponding to the pixel data from the print image data after rendering processing (step S202), and the series The process is executed (steps S204 to S214).
When the print image data after the color conversion processing is input, the N-value conversion processing unit 16 performs N-value conversion processing (
Image information (data) of gradation number M in the print image data
Is converted into image information (data) having a gradation number N (M ≧ N ≧ 2) (step S108).

When the printing unit 18 acquires the image data for printing after the N-value conversion processing from the N-value conversion processing unit 16,
Based on the image data for printing, the print head 200 is used to form dots on the print medium,
An image is printed (step S110).
Similar to the first embodiment, the print result is as shown in FIG. 12B. Compared with FIG. 12A printed without performing the print density conversion process of the present invention, characters are printed. There is no particular difference in the print density in the area, but the print density in the graphic area is clearly shown in FIG.
It can be seen that the density of the print result shown in b) is lighter overall than the print result of FIG. That is, the print result in FIG. 12B is a print image in which the contrast between the character region and the non-character region is high, and the character region portion can be clearly seen.

As described above, the printing apparatus 1 according to the present embodiment performs color conversion on the character area image in the image data for printing using the LUTA whose density upper limit value of the color space used for color conversion is higher than the LUTB. On the other hand, it is possible to perform color conversion using LUTB for an image in an area other than characters.
As a result, the image of the character area can be printed with a higher density than the image of the area other than the character area, so that the occurrence of cockling phenomenon and curling phenomenon is suppressed and the contrast is high (the character area is clearly defined). It is possible to obtain a printing result.

In the second embodiment, the printing image data acquisition unit 10 corresponds to the printing image data acquisition unit of the form 1 or 23, and the rendering processing unit 12 and the print density changing unit 14 are
Corresponding to the print density changing means of any one of Embodiments 1, 3, 23 and 25, the N-value conversion processing unit 16
The printing unit 18 corresponds to the printing unit of mode 1.
In the second embodiment, steps S100 to S102 are the same as those in the eighth and sixteenth aspects.
, 30 and 38, corresponding to the printing image data acquisition step, step S10
4 to S106 correspond to the print density changing step of any one of forms 8, 10, 16, 18, 30, 32, 38 and 40, and steps S108 to S110 correspond to the print steps of form 8 or 16. .
[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to the drawings. 15 to 20 illustrate a printing apparatus, a printing apparatus control program, a printing apparatus control method, and an image processing apparatus according to the present invention.
It is a figure which shows 3rd Embodiment of an image processing program and an image processing method.

Here, the printing apparatus according to the present embodiment performs a print density change process before the color conversion process.
This is different from the first and second embodiments.
Hereinafter, the same components as those in the first and second embodiments are denoted by the same reference numerals, description thereof will be omitted, and only different portions will be described.
First, the configuration of a printing apparatus according to the third embodiment of the present invention will be described with reference to FIG. FIG. 15 is a block diagram showing the configuration of the printing apparatus 2 according to the third embodiment of the present invention.

As illustrated in FIG. 15, the printing apparatus 2 includes a printing image data acquisition unit 10, a rendering processing unit 12, and a printing density changing unit 20 that changes the printing density of the printing image data before color conversion processing. , A color conversion unit 22 that converts print image data having RGB color information into print image data of CMYK color information, an N-value conversion processing unit 16, and a print unit 18. Yes.

The print density changing unit 20 converts the RGB gradation values (density value or luminance value) of each pixel of the image data for printing having RGB color information after rendering processing into an image of a character-only region,
It has a function to change the print density of the image of the image data for printing by changing it based on the print density information separately prepared for the image of the character area having the background and the image of the area other than the character. Yes.

The color conversion unit 22 uses the look-up table in which color conversion information from RGB to CMYK is set, and the R of each pixel of the printing image data whose print density has been changed by the print density change unit 20.
It has a function of converting GB color information into CMYK color information.
Note that the printing image data acquisition unit 10, the rendering processing unit 12, the N-value conversion processing unit 16, and the printing unit 18 have the same functions and configurations as those in the first and second embodiments, and thus description thereof is omitted. .

Further, a detailed configuration of the print density changing unit 20 will be described with reference to FIG. Here, FIG.
FIG. 3 is a block diagram showing a detailed configuration of a print density changing unit 20.
As shown in FIG. 16, the print density changing unit 20 includes a density control unit 20a and a density adjustment unit 20b.
And a print density information storage unit 20c.
When the density control unit 20a acquires the image data for printing after rendering processing from the rendering processing unit 12, the image data corresponding to the pixel data that has not been subjected to the printing density change processing and the pixel data in the printing image data. A function for selecting information and determining from the selected image element information whether the pixel data to be processed is pixel data of an image belonging to a character, pixel data of an image belonging to a character having a background, or pixel data other than a character have. Furthermore,
Based on the determination result, control information for controlling the density adjusting unit 20b is generated, and the control information is output to the density adjusting unit 20 together with the selected pixel data.

Here, the control information includes first control information when the selected pixel data is pixel data of only characters, second control information when the selected pixel data is pixel data other than characters, and characters having a background. Any one of the third control information in the case of the pixel data is generated and output.
Further, the printing apparatus 2 includes the printing image data acquisition unit 10 and the rendering processing unit 12.
, The print density changing unit 20, the color converting unit 22, the N-value conversion processing unit 16, and the printing unit 18.
Are provided with a computer system for executing the software for controlling the hardware necessary for realizing the functions. The hardware configuration of this computer system is the configuration shown in FIG. 5 as in the first and second embodiments.

Furthermore, the flow of printing processing in the printing apparatus 2 configured as described above will be described with reference to FIG. Here, FIG. 17 is a flowchart showing a printing process in the printing apparatus 2.
As shown in FIG. 17, the printing process first proceeds to step S500, where the printing image data acquisition unit 10 determines whether or not there is a printing instruction from a printing instruction terminal (not shown) such as a personal computer. If it is determined that there has been (Yes), the process proceeds to step S502. If not (No), the determination process is repeated until there is a print instruction.

When the process proceeds to step S502, the print image data acquisition unit 10 acquires the print image data sent together with the print instruction from the print instruction terminal, and the process proceeds to step S504.
In step S504, the rendering processing unit 12 performs rendering processing on the image data for printing that needs to be rendered (for example, image data for printing having document image information created in a page description language) to generate an image. The data is converted into data, the image data for printing after the rendering process and the image element information corresponding to the image data are output to the print density changing unit 20, and the process proceeds to step S506.

In step S506, the print density changing unit 20 changes the print density of the image of the print image data based on the print image data before the color conversion process acquired from the rendering processing unit 12, and the process proceeds to step S508.
In step S508, the color conversion unit 22 converts the RGB color information of each pixel in the print image data after changing the print density into CMYK color information, and the process proceeds to step S510.

In step S510, the N-value conversion processing unit 16 executes an N-value conversion process on the image information of the number of gradations M in the print image data after the color conversion process, and the image information of the number of gradations M is converted into a gradation. The image information is converted into image information of the characteristic N, and the process proceeds to step S512. For example, the image information of the number of gradations M is converted into the image information of the number of gradations N using a dither matrix stored in the storage device 70.

In step S512, the printing unit 18 drives the print head 200 based on the print image data after the N-ary processing, prints the image of the print image data on a print medium, and ends the process.
Next, the operation of the present embodiment will be described with reference to FIGS.
Here, FIG. 18 is a flowchart showing the print density changing process in the print density changing unit 20. FIG. 19 is a flowchart showing density adjustment processing in the density adjustment unit 20b. FIG. 20A is a diagram illustrating an example of print density information for an image of only a character and a region other than the character, and FIG. 20B is an example of print density information generation for an image of a character region having a background. FIG.

Since the processing up to the rendering process is the same as in the first embodiment, the operation from the print density change process will be described below.
When the print image data after the rendering process is input to the density control unit 20a (the branch of “Yes” in step S600), the print density changing unit 20 outputs unprocessed pixel data and the corresponding pixel. Image element information for data is selected (step S602).
. Further, based on the selected image element information, it is determined whether or not the selected pixel data belongs to a character (step S604). Here, when the type of image element of the pixel data belongs to a character (“Yes” branch in step S604), it is next determined whether or not the character to which the pixel data belongs has a background (step S606). ). If there is no background ("No" branch in step S606), first control information is generated and output to the density adjustment unit 20b together with the selected pixel data (step S616). On the other hand, if the character to which the selected pixel data belongs has a background ("Yes" branch in step S606), third control information is generated and output to the density adjustment unit 20b together with the selected pixel data. (Step S608). In addition, when the type of the image element of the selected pixel data does not belong to a character (“No” branch in step S604), the second control information is generated, and the density adjustment unit together with the selected pixel data It outputs to 20b (step S618).

When the control information and the pixel data are input, the density adjustment unit 20b executes density adjustment processing (step S610).
When the density adjustment process is executed, the density adjustment unit 20b determines whether or not the input control information is the first control information (step S700). If it is the first control information (“Yes” in step S700), the print density information for the character image is read and acquired from the print density information storage unit 20c (step S702), and the acquired character image is acquired. On the basis of the print density information for use, the R, G, B density values of the input pixel data are adjusted (step S7).
04).

Here, the print density information for the character image includes R, G, B input densities and the adjusted R, G, B
The relationship with each output density is a relationship such as a straight line F shown in FIG. Further, the print density information for images other than characters has a relationship between the input density and the adjusted output density as shown in FIG.
The relationship is like a straight line G shown in FIG. That is, the print density information for character images is set to have a higher adjusted print density than the print density information for images other than characters.

The print density information for character images and the print density information for images other than characters are a data table in which print density data after adjustment is set for input density data before density adjustment.
That is, for example, when pixel data of R “10”, G “100”, and B “100” is input, the density adjustment unit 20 b prints the print density information for the character image stored in the print density information storage unit 20 c. The adjusted density values of R, G, and B are acquired from the (data table), and the density values of the input pixel data are changed to the acquired density values. For example, R “10”, G “1
The pixel data of “00” and B “100” are changed to the pixel data of R “0”, G “90”, and B “90”.

On the other hand, when the input control information is not the first control information (the “No” branch in step S700) but the second control information (the “Yes” branch in step S706), the density adjustment unit 20b Print density information for images other than characters is read and acquired from the print density information storage unit 20c (step S708), and based on the acquired print density information for images other than characters,
Each density value of R, G, B of the input pixel data is adjusted (step S704).

That is, when the pixel data of R “10”, G “100”, and B “100” is input, the density adjustment unit 20b print density information for images other than characters stored in the print density information storage unit 20c. The adjusted RGB density values are acquired from the (data table), and each density value of the input pixel data is changed to the acquired density value. For example, R “10”, G “100”,
The pixel data of B “100” is changed to the pixel data of R “0”, G “45”, and B “45”.

If the input control information is not the second control information but the third control information (“No” branch in step S706), the density adjusting unit 20b reads the character image from the print density information storage unit 20c. In addition to the print density information and the print density information for images other than characters, the mixture ratio information in which the adjustment ratio mixture ratio is set is read and acquired (step S710), and the acquired print density for the background character image is obtained. Based on the information, R, G, and B density values of the input pixel data are adjusted (step S704).

Here, in the character image having the background, the density of the background portion is often relatively thin, and it can be said that the cockling phenomenon and the curl phenomenon are less likely to occur as compared with the solid graphic region portion. However, if the density adjustment is simply performed using the print density information for character images, ink corresponding to the background density is printed, so the background is solid and the density before adjustment is relatively high. May cause a cockling phenomenon in the character area.

Therefore, in the present embodiment, character image print density information and print density information for images other than characters are mixed based on the mixing ratio information shown in FIG. The density adjustment processing is performed using the density information.
Here, the mixing ratio information includes the mixing ratio of the print density information for the character image and the mixing ratio of the print density information for the image other than the character with respect to the density of the background portion of the character image (background density). FIG.
It is a data table set so as to have a relationship as shown in 0 (b). FIG. 20 (b)
Using the data table, density information is generated by mixing the characters shown in FIG.

That is, when the pixel data of R “10”, G “100”, and B “100” is input, the density adjustment unit 20 b firstly mix ratio information (data table) stored in the print density information storage unit 20 c. From the background density of the character image, the mixing ratio of the print density information for the character image (hereinafter referred to as the first mixing ratio) and the mixing ratio of the print density information for the image other than the characters (hereinafter referred to as the second density).
(Referred to as mixing ratio). Here, it is assumed that the first mixing ratio is 60 [%] and the second mixing ratio is 40 [%].

Next, the density adjustment unit 20b calculates R “10”, G “100”, and B “from the print density information for character images and the print density information for images other than characters stored in the print density information storage unit 20 c. 1
The RGB density value after adjustment for “00” is acquired. Here, R “0”, G “90”, and B “90” are acquired from the print density information for character images, and R “0”, G “45”, and B “90” are obtained from the print density information for images other than characters. It is assumed that “45” is acquired.

The density adjusting unit 20b calculates the adjusted R, G, and B density values using the acquired first and second mixing ratios and the adjusted R, G, and B density values. Specifically, a value obtained by multiplying the acquired density values of R, G, B for the obtained character image by the first mixing ratio, and R,
The density value after adjustment is calculated by adding the values obtained by multiplying the density values of G and B by the second mixing ratio. As a result, R “0 × 0.6 + 0 × 0.4 = 0”, G “90 × 0.6 + 45 × 0.4
= 54 + 18 = 72 ”and B“ 90 × 0.6 + 45 × 0.4 = 54 + 18 = 72 ”are calculated.

Then, the density adjusting unit 20b performs R “10”, G “100”, B of the input pixel data.
Each density value of “100” is changed to the above calculated R “0”, G “72”, and B “72”.
When the density adjustment processing is completed for the selected pixel data, the print density changing unit 20
When it is determined whether or not the density adjustment processing has been completed for all the pixel data in the print image data to be processed, and when it is determined that the processing has ended (“Yes” branch in step S612)
Outputs the print image data after the print density change to the color conversion unit 22 (step S614),
A series of processes is terminated and the process returns to the original process.

If the density adjustment processing has not been completed for all pixel data (step S61).
(No. 2 branch), the density control unit 20a selects unprocessed pixel data and image element information corresponding to the pixel data from the print image data after rendering processing (
Step S602), the above series of processing is executed (Steps S604 to S618).
The color conversion unit 22 converts the RGB color information of each pixel of the print image data after the print density change into CMYK color information based on the lookup table, and the print image data after the color conversion is converted to N The data is output to the value processing unit 16 (step S508).

When the print image data after the color conversion processing is input, the N-value conversion processing unit 16 performs N-value conversion processing (
Image information (data) of gradation number M in the print image data
Is converted into image information (data) having a gradation number N (M ≧ N ≧ 2) (step S510).
When the printing unit 18 acquires the image data for printing after the N-value conversion processing from the N-value conversion processing unit 16,
Based on the image data for printing, the print head 200 is used to form dots on the print medium,
The image is printed (step S512).

This print result is as shown in FIG. 12B, as in the first and second embodiments, and is compared with FIG. 12A printed without performing the print density conversion processing of the present invention. Then, there is no particular difference between the print density in the character area, but the print density in the graphic area is clearly greater in the print result shown in FIG. 12B than in the print result in FIG. It can be seen that the concentration is getting thinner. That is, the print result in FIG. 12B is a print image in which the contrast between the character region and the non-character region is high, and the character region portion can be clearly seen.

As described above, the printing apparatus 2 according to the present embodiment can perform the print density change process on the print image data before color conversion. Thereby, it is possible to easily change the print density.
In addition, for the image of the character area in the image of the print image data before color conversion, the density upper limit after density adjustment is printed using print density information higher than the print density information for images other than characters. On the other hand, it is possible to perform the density adjustment process on the image in the area other than the character by using the print density information for the image other than the character. Further, for an image of a character area having a background, density adjustment is performed using information obtained by mixing the print density information for the character image and the print density information for an image other than the character based on the mixture ratio information. Processing can be performed.

As a result, the image of the character area can be printed with a higher density than the image of the area other than the character area, so that the occurrence of cockling phenomenon and curling phenomenon is suppressed and the contrast is high (the character area is clearly defined). It is possible to obtain a printing result. Also,
For character areas with a background, it is possible to set an intermediate print density between the character-only area and the non-character area. This prevents the occurrence of cockling and curling in the background character area. While suppressing, it is possible to obtain a print result with high contrast (a character area is clearly printed).

In the third embodiment, the printing image data acquisition unit 10 corresponds to the printing image data acquisition unit of the form 1 or 23, and the rendering processing unit 12 and the print density changing unit 20 are
The color conversion unit 22, the N-value conversion processing unit 16, and the printing unit 18 correspond to the printing means of mode 1, corresponding to the printing density changing unit of any one of the modes 1, 2, 4, 23, 24, and 26. .
In the third embodiment, steps S500 to S502 are the same as those in the eighth and sixteenth aspects.
, 30 and 38, corresponding to the printing image data acquisition step, step S50
4 to S506 are forms 8, 9, 11, 16, 17, 19, 30, 31, 33, 38, 39.
And S41 to 41 correspond to the print density changing step, and Steps S508 to S512 correspond to the printing step of Form 8 or 16.
[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to the drawings. 21 to 24 show a printing apparatus, a printing apparatus control program and a printing apparatus control method, and an image processing apparatus according to the present invention.
It is a figure which shows 4th Embodiment of an image processing program and an image processing method.

Here, the printing apparatus according to the present embodiment performs a print density change process after the color conversion process.
This is different from the third embodiment.
Hereinafter, the same components as those in the first to third embodiments are denoted by the same reference numerals, description thereof is omitted, and only different portions are described.
First, the configuration of a printing apparatus according to the fourth embodiment of the present invention will be described with reference to FIG. FIG. 21 is a block diagram showing the configuration of the printing apparatus 3 according to the fourth embodiment of the present invention.

As shown in FIG. 21, the printing apparatus 3 converts the printing image data acquisition unit 10, the rendering processing unit 12, and printing image data having RGB color information into printing image data having CMYK color information. The color conversion unit 22 that performs the color conversion process, the print density change unit 20 that changes the print density of the image data for color printing, the N-value conversion processing unit 16, and the printing unit 18. Yes.

The print density changing unit 20 according to the present embodiment has the same configuration as that of the third embodiment, but has a slightly different function. Specifically, in the third embodiment, RGB
However, in this embodiment, print image data having CMYK color information is a processing target of the print density change process.

Therefore, the print density changing unit 20 according to the present embodiment uses the CMYK tone values (density values or luminance values) of the pixels of the print image data having the CMYK color information after the color conversion process.
Is changed on the basis of print density information separately prepared for an image of a character-only region, an image of a character region having a background, and an image of a region other than a character, thereby printing the image of the image data for printing It has a function to change the concentration. That is, the print density information storage unit 20
The print density information stored in c is a data table in which the density value after adjustment is set for the input density value of CMYK.

Note that the printing image data acquisition unit 10, the rendering processing unit 12, the color conversion unit 22, the N-value conversion processing unit 16, and the printing unit 18 have the same functions and configurations as those of the third embodiment. Omitted.
Further, a detailed configuration of the print density changing unit 20 in the present embodiment will be described.
Since the print density changing unit 20 has the same configuration as the detailed configuration of the print density changing unit 20 shown in FIG. 16 in the third embodiment, the present embodiment of each constituent unit is based on FIG. The function in will be described.

When the density control unit 20a obtains the print image data after the color conversion process from the color conversion unit 22, the print density change process in the print image data is unprocessed pixel data and an image corresponding to the pixel data. Select element information and determine from the selected image element information whether the pixel data to be processed is pixel data of an image belonging to a character, pixel data of an image belonging to a character having a background, or pixel data other than characters. It has a function. Furthermore, based on this determination result, it has a function of generating control information for controlling the density adjusting unit 20b and outputting it to the density adjusting unit 20 together with the selected pixel data.

Here, the control information includes first control information when the selected pixel data is pixel data of only characters, second control information when the selected pixel data is pixel data other than characters, and characters having a background. Any one of the third control information in the case of the pixel data is generated and output.
Further, the printing apparatus 3 includes the printing image data acquisition unit 10 and the rendering processing unit 12.
, The color conversion unit 22, the print density changing unit 20, the N-value conversion processing unit 16, and the printing unit 18.
Are provided with a computer system for executing the software for controlling the hardware necessary for realizing the functions. The hardware configuration of this computer system is the configuration shown in FIG. 5 as in the first to third embodiments.

Furthermore, the flow of printing processing in the printing apparatus 3 configured as described above will be described with reference to FIG. Here, FIG. 22 is a flowchart showing a printing process in the printing apparatus 3.
As shown in FIG. 17, the printing process first proceeds to step S800, where the printing image data acquisition unit 10 determines whether or not there is a printing instruction from a printing instruction terminal (not shown) such as a personal computer. If it is determined that there has been (Yes), the process proceeds to step S802. If not (No), the determination process is repeated until there is a print instruction.

When the process proceeds to step S802, the print image data acquisition unit 10 acquires the print image data sent together with the print instruction from the print instruction terminal, and the process proceeds to step S804.
In step S804, the rendering processing unit 12 performs rendering processing on the image data for printing that needs to be rendered (for example, image data for printing having document image information created in a page description language) to generate an image. The data is converted into data, the image data for printing after the rendering process and the image element information corresponding to the image data are output to the print density changing unit 20, and the process proceeds to step S806.

In step S806, the color conversion unit 22 converts the RGB color information of each pixel in the print image data after rendering processing into CMYK color information, and in step S808.
Migrate to
In step S808, the print density changing unit 20 changes the print density of the image of the print image data based on the print image data after color conversion processing acquired from the color conversion unit 22, and the process proceeds to step S810.

In step S810, the N-value conversion processing unit 16 executes N-value conversion processing on the image information of the number of gradations M in the print image data after the change of the print density, and the image information of the number of gradations M is stored in the gradation. The image information is converted into image information of the characteristic N, and the process proceeds to step S812. For example, the image information of the number of gradations M is converted into the image information of the number of gradations N using a dither matrix stored in the storage device 70.

In step S812, the printing unit 18 drives the print head 200 based on the print image data after the N-ary processing, prints the image of the print image data on a print medium, and ends the process.
Next, based on FIG. 23, operation | movement of this Embodiment is demonstrated.
Here, FIG. 23 is a flowchart showing the print density changing process in the print density changing unit 20 of the present embodiment. FIG. 24 is a flowchart showing density adjustment processing in the density adjustment unit 20b of the present embodiment.

Since the processing up to the rendering processing is the same as in the first embodiment, the operation from the color conversion processing will be described below.
When the printing image data after the rendering process is input, the color conversion unit 22 converts the RGB color information of each pixel of the printing image data after the rendering process into CMYK color information based on a lookup table. Then, the image data for printing after the color conversion is output to the print density changing unit 20 (step S806).

When the print image data after the color conversion process is input to the density control unit 20a ("Yes" branch in step S900), the print density changing unit 20 performs processing of the unprocessed pixel data and the print density changing process. Image element information for pixel data is selected (step S902). Further, based on the selected image element information, it is determined whether or not the selected pixel data belongs to a character (step S904). Here, when the type of image element of the pixel data belongs to a character (“Yes” branch in step S904), the character to which the pixel data belongs is
It is determined whether or not there is a background (step S906). If there is no background ("No" branch in step S906), first control information is generated and output to the density adjustment unit 20b together with the selected pixel data (step S916). On the other hand, when the character to which the selected pixel data belongs has a background ("Yes" branch in step S906),
The third control information is generated, and is output to the density adjusting unit 20b together with the selected pixel data (step S908). In addition, when the type of the image element of the selected pixel data does not belong to a character (“No” branch of step S904), the second control information is generated, and the density adjustment unit together with the selected pixel data It outputs to 20b (step S918).

When the control information and the pixel data are input, the density adjustment unit 20b executes density adjustment processing (step S910).
When the density adjustment process is executed, the density adjustment unit 20b determines whether or not the input control information is the first control information (step S1000). If it is the first control information (“Yes” branch in step S1000), the character C for the character image from the print density information storage unit 20c,
The print density information of M, Y, and K is read and acquired (step S1002), and the density values of C, M, Y, and K of the input pixel data are based on the acquired print density information for the character image. Is adjusted (step S1004).

Here, the print density information for the character image includes C, M, Y, and K input densities and the adjusted C, M
As in the case of R, G, and B in the third embodiment, the relationship between the output densities of Y, K, and K is as follows.
Assume that the relationship is like a straight line F shown in FIG. Similarly, the print density information for images other than characters has a relationship between the input density and the adjusted output density as shown in FIG.
It is assumed that the relationship is like a straight line G shown in FIG. That is, R, G,
As in the case of B, the print density information for character images is set to be higher in print density after adjustment than the print density information for images other than characters.

In other words, the density adjustment unit 20b, for example, C “0”, M “100”, Y “100”, K “
When pixel data of “0” is input, the C, M, Y, and adjusted C, M, Y, and K print density information (data table) for character images stored in the print density information storage unit 20c are adjusted. Each density value of K is acquired, and each density value of the input pixel data is changed to the acquired density value. For example, pixel data of C “0”, M “100”, Y “100”, and K “0” is converted to C “0”.
, M “90”, Y “90”, and K “0”.

On the other hand, when the input control information is not the first control information (the “No” branch in step S1000) but the second control information (the “Yes” branch in step S1006), the density adjustment unit 20b Read and obtain C, M, Y, and K print density information for images other than characters from the print density information storage unit 20c (step S1008), and based on the obtained print density information for images other than characters, The C, M, Y, and K density values of the input pixel data are adjusted (step S1004).

That is, when the pixel data of C “0”, M “100”, Y “100”, and K “0” is input, the density adjustment unit 20 b receives an image other than characters stored in the print density information storage unit 20 c. C for
C, M, Y, K density values after adjustment are acquired from the print density information (data table) of M, Y, K, and the density values of the input pixel data are obtained as the acquired density values. Change to
For example, pixel data of C “0”, M “100”, Y “100”, and K “0” are converted into C “0”,
The pixel data is changed to M “45”, Y “45”, and K “0”.

When the input control information is not the second control information but the third control information (“No” branch in step S1006), the density adjustment unit 20b reads the character image from the print density information storage unit 20c. In addition to C, M, Y, and K print density information and C, M, Y, and K print density information for images other than characters, read and acquire the mixture ratio information in which the adjustment ratio mixture ratio is set. (Step S1010) Based on the acquired print density information for the background character image, the C, M, Y, and K density values of the input pixel data are adjusted (Step S1004).

In the present embodiment, as in the third embodiment, for character images having a background, C, M, Y for character images, based on the mixture ratio information shown in FIG. The density adjustment processing is performed using data obtained by mixing the print density data set for the print density information for K and the print density information for C, M, Y, and K for images other than characters.
In other words, when the pixel data of C “0”, M “100”, Y “100”, and K “0” is input, the density adjustment unit 20 b first stores the mixing ratio stored in the print density information storage unit 20 c. information(
From the data table, the mixing ratio of the printing density information for the character image (hereinafter referred to as the first mixing ratio) and the mixing ratio of the printing density information for the image other than the characters (hereinafter referred to as the first mixing ratio) with respect to the background density of the character image. (Referred to as 2 mixing ratio). Here, it is assumed that the first mixing ratio is 60 [%] and the second mixing ratio is 40 [%].

Next, the density adjustment unit 20b calculates C “0”, M “100”, and Y “from the print density information for character images and the print density information for images other than characters stored in the print density information storage unit 20 c. 10
The adjusted density values of C, M, Y, and K for “0” and K “0” are acquired. Here, C “0”, M “90”, Y “90”, and K “0” are acquired from the print density information for character images, and C “0”, M from the print density information for images other than characters. It is assumed that “45”, Y “45”, and K “0” are acquired.

The density adjusting unit 20b obtains the acquired first and second mixing ratios and the adjusted C, M, Y, K
Are used to calculate the adjusted C, M, Y, and K density values. Specifically, a value obtained by multiplying the obtained density values of C, M, Y, and K for the character image by the first mixing ratio, and density values of C, M, Y, and K for images other than characters. Is added to the value obtained by multiplying the value by the second mixing ratio to calculate an adjusted density value. As a result, C “0 × 0.6 + 0 × 0.4 = 0”, M “90 × 0.
6 + 45 × 0.4 = 54 + 18 = 72 ”, Y“ 90 × 0.6 + 45 × 0.4 = 54 + 18
= 72 "and K" 0x0.6 + 0x0.4 = 0 "are calculated.

Then, the density adjustment unit 20b receives C “0”, M “100”, and Y “of the input pixel data.
The density values of “100” and “K” are set to the above calculated C “0”, M “72”, Y “72”, K
Change to “0”.
When the density adjustment processing is completed for the selected pixel data, the print density changing unit 20
When it is determined whether or not the density adjustment processing has been completed for all the pixel data in the print image data to be processed, and when it is determined that the processing has ended ("Yes" branch in step S912)
Outputs the print image data after changing the print density to the color converter 22 (step S914),
A series of processes is terminated and the process returns to the original process.

If the density adjustment processing has not been completed for all pixel data (step S91).
(No. 2 branch), the density control unit 20a selects unprocessed pixel data and image element information corresponding to the pixel data from the print image data after rendering processing (
Step S902), the above series of processing is executed (Steps S904 to S918).
When the print image data after the print density changing process is input, the N-value conversion processing unit 16 executes an N-value conversion process (halftone process), and the image information (the number of gradations M in the print image data ( (Data) is converted into image information (data) having the number of gradations N (M ≧ N ≧ 2) (step S81).
0).

When the printing unit 18 acquires the image data for printing after the N-value conversion processing from the N-value conversion processing unit 16,
Based on the image data for printing, the print head 200 is used to form dots on the print medium,
The image is printed (step S812).
This print result is as shown in FIG. 12B, as in the first to third embodiments, and is compared with FIG. 12A printed without performing the print density conversion process of the present invention. Then, there is no particular difference between the print density in the character area, but the print density in the graphic area is clearly greater in the print result shown in FIG. 12B than in the print result in FIG. It can be seen that the concentration is getting thinner. That is, the print result in FIG. 12B is a print image in which the contrast between the character region and the non-character region is high, and the character region portion can be clearly seen.

As described above, the printing apparatus 3 according to the present embodiment can perform the print density changing process on the print image data after color conversion. As a result, the print density for the color used for printing can be changed, so that the print density can be changed more accurately.
In addition, for the image of the character area in the image of the print image data after color conversion, the density upper limit after density adjustment is printed using print density information higher than the print density information for images other than characters. On the other hand, it is possible to perform the density adjustment process on the image in the area other than the character by using the print density information for the image other than the character. Further, for an image of a character area having a background, density adjustment is performed using information obtained by mixing the print density information for the character image and the print density information for an image other than the character based on the mixture ratio information. Processing can be performed.

As a result, the image of the character area can be printed with a higher density than the image of the area other than the character area, so that the occurrence of cockling phenomenon and curling phenomenon is suppressed and the contrast is high (the character area is clearly defined). It is possible to obtain a printing result. Also,
For character areas with a background, it is possible to set an intermediate print density between the character-only area and the non-character area. This prevents the occurrence of cockling and curling in the background character area. While suppressing, it is possible to obtain a print result with high contrast (a character area is clearly printed).

In the fourth embodiment, the print image data acquisition unit 10 corresponds to the print image data acquisition unit of the form 1 or 23, and the print density change unit 20 has the forms 1, 2, 5, 23, 24.
The N-value conversion processing unit 16 and the printing unit 18 correspond to the printing unit of the first mode.
In the fourth embodiment, steps S800 to S802 are the same as those in the eighth and sixteenth embodiments.
, 30 and 38, corresponding to the printing image data acquisition step, step S80.
8 corresponds to the print density changing step of any one of forms 8, 9, 12, 16, 17, 20, 30, 31, 34, 38, 39 and 42, and steps S810 to S812 are forms 8 or 16. Corresponds to the printing step.

[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described with reference to the drawings. 25 to 29 illustrate a printing apparatus, a printing apparatus control program and a printing apparatus control method, and an image processing apparatus according to the present invention.
It is a figure which shows 5th Embodiment of an image processing program and an image processing method.
Here, the printing apparatus of the present embodiment is characterized in that the print density changing process is performed during the N-value conversion process.
This is different from the first to fourth embodiments.
Hereinafter, the same components as those in the first to fourth embodiments are denoted by the same reference numerals, description thereof is omitted, and only different portions are described.
First, the configuration of a printing apparatus according to the fifth embodiment of the present invention will be described with reference to FIG. FIG. 25 is a block diagram showing the configuration of the printing apparatus 4 according to the fifth embodiment of the present invention.

As shown in FIG. 25, the printing apparatus 4 converts the printing image data acquisition unit 10, the rendering processing unit 12, and the printing image data having RGB color information into printing image data having CMYK color information. The color conversion unit 22 that performs printing, the print density change unit 24 that executes N-value conversion processing that accompanies the print density change processing on the print image data, and the printing unit 18 are included.
The print density changing unit 24 displays the image from the rendering processing unit 12 when the image information included in the print image data is data expressed by the number of gradations M (for example, CMYK data having the number of gradations 256). Based on the element information, a print density changing process for selectively using the dither matrix having a different dither threshold value for each type of image element to convert the image information of the number of gradations M into image information of the number of gradations N. It has a function of executing the accompanying N-value processing.

In the present embodiment, the dither matrix includes a first dither matrix (hereinafter referred to as a first DM) for a character image whose image element type belongs to a character, and a character other than a character whose image element type belongs to a character other than a character. There is a second dither matrix for images (hereinafter referred to as second DM), which is stored in advance in a dither matrix storage unit 24c described later.
Further, a detailed configuration of the print density changing unit 24 will be described with reference to FIG. Here, FIG.
FIG. 3 is a block diagram showing a detailed configuration of a print density changing unit 24.

As shown in FIG. 26, the print density changing unit 24 includes a density control unit 24a, an N-value conversion unit 24b, and a dither matrix storage unit 24c.
When the N-value conversion unit 24b acquires the print image data after the color conversion process from the color conversion unit 22, the N-value conversion unit 24b corresponds to the unprocessed pixel data and the pixel data in the print image data. It has a function of selecting image element information and determining whether the pixel data to be processed is pixel data of an image belonging to a character or other pixel data from the selected image element information. Furthermore, based on this determination result, it has a function of generating control information for controlling an N-value conversion process of an N-value conversion unit 24b described later and outputting it to the N-value conversion unit 24b together with selected pixel data. .

Here, the control information is generated by either the first control information when the selected pixel data belongs to a character or the second control information when the selected pixel data belongs other than a character. And output.
When the control information and the pixel data are input from the density control unit 24a, the N-value conversion unit 24b reads the first DM or the second DM from the dither matrix storage unit 24c based on the control information, and uses the read dither matrix. Then, the input pixel data of the number of gradations M is converted into pixel data of the number of gradations N. Specifically, when the first control information is input, the first DM is read from the dither matrix storage unit 24c. When the N-value conversion process is executed and the second control information is input, the second DM is read from the dither matrix storage unit 24c and the N-value conversion process is executed.

Here, in the first DM and the second DM, the dot generation ratio is second in the first DM.
Both dither thresholds are set to be higher than DM. In the N-value conversion processing, the density value of each pixel is compared with the dither threshold value. If the density value is equal to or greater than the dither threshold value, the dot is turned on. If the density value is less than the dither threshold value, the dot is turned off. That is, since the first DM dither threshold value is smaller than the second DM dither threshold value, the dot generation ratio is higher when the N-value conversion processing is performed using the first DM. A high dot generation ratio means that dots are likely to be generated. Therefore, the higher the dot generation ratio, the higher the density. Therefore, as described above, the character region is subjected to N-value processing using the first DM, and the image region other than the character is subjected to N-value processing using the second DM. The image can be set to have a higher print density than the image in the area other than the characters.

The dither matrix storage unit 24c has a function of storing the first DM and the second DM described above.
Further, the printing apparatus 4 includes the printing image data acquisition unit 10 and the rendering processing unit 12.
In order to realize the above functions in the color conversion unit 22, the print density changing unit 24, the printing unit 18 and the like on software, and to execute software for controlling hardware necessary for realizing the functions. Computer system. The hardware configuration of this computer system is the configuration shown in FIG. 5 as in the first and second embodiments.

Furthermore, the flow of printing processing in the printing apparatus 4 configured as described above will be described with reference to FIG. Here, FIG. 27 is a flowchart showing a printing process in the printing apparatus 4.
As shown in FIG. 27, the printing process first proceeds to step S1100, where the printing image data acquisition unit 10 determines whether or not there is a printing instruction from a printing instruction terminal (not shown) such as a personal computer. If it is determined that there has been (Yes), the process proceeds to step S1102, and if not (No), the determination process is repeated until there is a print instruction.

When the process proceeds to step S1102, the print image data acquisition unit 10 acquires the print image data sent together with the print instruction from the print instruction terminal, and the process proceeds to step S1104.
Migrate to
In step S1104, the rendering processing unit 12 performs rendering processing on the image data for printing that needs to be rendered (for example, image data for printing having document image information created in a page description language) to generate an image. The data is converted into data, the image data for printing after the rendering process and the image element information corresponding to the image data are output to the color conversion unit 22, and the process proceeds to step S1106.

In step S1106, the color conversion unit 22 converts color information other than CMYK in the image of the print image data acquired from the rendering processing unit 12 into RGB color information, and the process proceeds to step S1108.
In step S1108, the print density changing unit 24 uses the dither matrix corresponding to the type of control information to execute N-value processing on the image information of the number of gradations M in the print image data after color conversion processing. Then, the image information of the number of gradations M is converted into image information of the number of gradations N, and the process proceeds to step S1110.

In step S1110, the printing unit 18 drives the print head 200 based on the print image data after the N-ary processing, prints the image of the print image data on a print medium, and ends the process.
Next, based on FIG.28 and FIG.29, operation | movement of this Embodiment is demonstrated.
Here, FIG. 28 is a flowchart showing an N-value conversion process with a print density change process in the print density change unit 24 of the present embodiment. FIG. 29A shows the first D for character images.
It is a figure which shows an example of M, (b) is a figure which shows an example of 2nd DM for images other than a character.

Since the process up to the color conversion process is the same as that of the fourth embodiment, the operation from the print density change process will be described below.
When the print image data after the color conversion process is input, the print density changing unit 24 executes an N-value conversion process that accompanies the print density change process (step S1108).
When the N-value conversion process with the print density change process is executed, first, the image data for color printing after the color conversion process is input to the density control unit 24a ("Yes" branch in step S1200). Then, the density control unit 24a selects pixel data that has not been subjected to N-value conversion processing (print density change processing) and image element information for the pixel data from the input image data for printing (step S1202). Further, based on the selected image element information, it is determined whether or not the selected pixel data belongs to a character. If the type of image element of the pixel data belongs to a character, first control information is generated, This is output together with the selected pixel data to the N-value conversion unit 24b (step S1204). On the other hand, if the image element type of the selected pixel data does not belong to a character, second control information is generated and output to the N-value conversion unit 24b together with the selected pixel data (step S1204).

When the control information is input, the N-value conversion unit 24b determines whether the input control information is the first control information (step S1206). If it is the first control information (“Yes” branch of step S1206), the first DM is read out and acquired from the dither matrix storage unit 24c (step S1208), and the input is made based on the acquired first DM. The pixel data having the gradation number M is converted into pixel data having the gradation number N (step S1210).
.

Here, the first DM has the dither threshold shown in FIG. 29A, and the second DM is the same as that shown in FIG.
It has a dither threshold value shown in 9 (b). In the example shown in FIG. 29, the pixel data is 0 to 0.
A dither matrix of 2 rows × 2 columns in the case of having an 8-bit gradation value of 255. The example shown in FIG. 29 is a dither matrix prepared for explaining the difference between the first DM and the second DM. Originally, it is possible to obtain an appropriate printing result by using a larger dither matrix. .

As can be seen by comparing FIGS. 29A and 29B, the first DM shown in FIG. 29A is composed of a dither threshold value that is smaller than the second DM shown in FIG. 29B. That is, it is possible to execute the N-value process in which the first DM has a higher dot generation frequency than the second DM.
On the other hand, when the input control information is the second control information (“No” in step S1206).
Branching), the N-value conversion unit 24b reads and acquires the second DM from the dither matrix storage unit 24c (step S1216). Based on the acquired second DM, the input pixel data of the number of gradations M is input. The pixel data is converted into pixel data having the number of gradations N (step S1210).

The print density changing unit 24 determines whether or not the N-value conversion process with the print density change process has been completed for all the pixel data in the print image data to be processed. (“Yes” branch of step S1212) outputs the image data for printing after the N-value process accompanied by the print density change process to the printing unit 18 (step S1214), ends the series of processes, and returns to the original process. Return to.

If the N-value conversion process with the print density change process has not been completed for all the pixel data (“No” branch in step S1212), the density control unit 24a performs printing for the color conversion process. From the image data, unprocessed pixel data and image element information corresponding to the pixel data are selected (step S1202), and the above-described series of processing is executed (step S120).
4-S1216).

When the printing unit 18 acquires the printing image data after the N-value conversion process accompanied by the printing density changing process from the printing density changing unit 24, the printing unit 18 sets dots on the printing medium using the printing head 200 based on the printing image data. Form and print an image (step S1214).
This print result is as shown in FIG. 12B, as in the first to fourth embodiments, and is compared with FIG. 12A printed without performing the print density conversion process of the present invention. Then, there is no particular difference between the print density in the character area, but the print density in the graphic area is clearly greater in the print result shown in FIG. 12B than in the print result in FIG. It can be seen that the concentration is getting thinner. That is, the print result in FIG. 12B is a print image in which the contrast between the character region and the non-character region is high, and the character region portion can be clearly seen.

As described above, the printing apparatus 1 according to the present embodiment performs color conversion on the character area image in the image data for printing using the LUTA whose density upper limit value of the color space used for color conversion is higher than the LUTB. On the other hand, it is possible to perform color conversion using LUTB for an image in an area other than characters.
As a result, the image of the character area can be printed with a higher density than the image of the area other than the character area, so that the occurrence of cockling phenomenon and curling phenomenon is suppressed and the contrast is high (the character area is clearly defined). It is possible to obtain a printing result.

In the fifth embodiment, the print image data acquisition unit 10 corresponds to the print image data acquisition unit of the form 1 or 23, and the print density change unit 24 corresponds to any of the forms 1, 6, 23, and 28. The printing unit 18 corresponds to the printing means of the first mode.
In the fifth embodiment, steps S1100 to S1102 are performed in the eighth mode.
Corresponding to the print image data acquisition step of any one of 16, 30, and 38, step S
1108 corresponds to the print density changing step of any one of forms 8, 13, 16, 21, 30, 35, 38, and 43, and step S1110 corresponds to the print step of form 8 or 16.

The printing apparatus according to the first to fifth embodiments is characterized in that the print density of the image of the printing image data is changed without changing the existing printing apparatus itself. It is not necessary to prepare a special one as the unit 18, and an existing ink jet printer can be used as it is. If the printing unit 18 is separated from the printing apparatuses 1 to 4 in the first to fifth embodiments, the function can be realized only by a general-purpose printing instruction terminal (image processing apparatus) such as a PC. It becomes.

The printing apparatuses 1 to 4 in the first to fifth embodiments can be applied not only to the line head type ink jet printer but also to a multi-pass type ink jet printer.
Further, in the first to fifth embodiments described above, FIGS. 6, 8, 9, 14, 17, 17, 18, 19, 22, 23, 24, 27, and 28 are used. In executing the processing shown in the flowchart, the case where the control program stored in advance in the ROM 64 is executed has been described. However, the present invention is not limited to this, and the program is recorded from the recording medium on which the program showing these procedures is recorded. May be read into the RAM 62 and executed. Alternatively, the program may be acquired from a network.

Here, the recording medium is a semiconductor recording medium such as RAM or ROM, a magnetic storage type recording medium such as FD or HD, an optical reading type recording medium such as CD, CDV, LD, or DVD, or a magnetic storage type such as MO. / Optical reading type recording medium, including any recording medium that can be read by a computer, regardless of electronic, magnetic, optical, or other reading methods.

In the third embodiment, the print density information of the image data for printing after the rendering process is changed. However, the present invention is not limited to this, and the print density change process is performed during the rendering process. It is also good. By doing so, the rendering module can also be configured to simultaneously perform the print density changing process, so that the processing speed can be improved.

1 is a block diagram illustrating a configuration of a printing apparatus 1 according to the present invention. 3 is a partially enlarged bottom view showing the structure of the print head 200. FIG. 3 is a block diagram illustrating a detailed configuration of a print density changing unit 14. FIG. 3 is a block diagram illustrating a detailed configuration of a color conversion unit 142. FIG. It is a figure which shows the hardware constitutions of the printing apparatus which concerns on this invention. 4 is a flowchart illustrating a printing process in the printing apparatus 1. It is a figure which shows an example of the image printed without performing the printing density change process of this invention. It is a flowchart which shows the printing density change process of this Embodiment. It is a flowchart which shows the color conversion process of this Embodiment. (A) is a schematic diagram which shows an example of the color space of LUTA, (b) is a schematic diagram which shows an example of the color space of LUTB. It is a figure which shows the numerical example of a color conversion process. (A) is a figure which shows an example of the image printed without performing the print density change process of this invention, (b) is a figure which shows an example of the print image which performed the print density change process of this invention. is there. It is a block diagram which shows the detailed structure of the color conversion part 142 in 2nd Embodiment. It is a flowchart which shows the color conversion process of the color conversion part 142 in 2nd Embodiment. 1 is a block diagram illustrating a configuration of a printing apparatus 2 according to the present invention. 3 is a block diagram illustrating a detailed configuration of a print density changing unit 20. FIG. 4 is a flowchart showing a printing process in the printing apparatus 2. 4 is a flowchart showing a print density changing process in a print density changing unit 20. It is a flowchart which shows the density | concentration adjustment process in the density | concentration adjustment part 20b. (A) is a figure which shows an example of the printing density information with respect to the image of only the character and the area | region other than a character, (b) is a figure which shows an example of the printing density information generation with respect to the image of the character area which has a background. . 1 is a block diagram illustrating a configuration of a printing apparatus 3 according to the present invention. 4 is a flowchart showing a printing process in the printing apparatus 3. It is a flowchart which shows the printing density change process in the printing density change part 20 of this Embodiment. It is a flowchart which shows the density adjustment process in the density adjustment part 20b of this Embodiment. 1 is a block diagram illustrating a configuration of a printing apparatus 4 according to the present invention. 3 is a block diagram illustrating a detailed configuration of a print density changing unit 24. FIG. 6 is a flowchart illustrating a printing process in the printing apparatus 4; It is a flowchart which shows the N-value-izing process accompanying the print density change process in the print density change part 24 of this Embodiment. (A) is a figure which shows an example of 1st DM for character images, (b) is a figure which shows an example of 2nd DM for images other than a character.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1-4 ... Printing apparatus, 200 ... Print head, 10 ... Image data acquisition part, 12 ... Rendering processing part, 14, 20, 24 ... Print density change part, 16 ... N-value conversion processing part, 18 ... Printing part, 22
... color converter, 60 ... CPU, 62 ... RAM, 64 ... ROM, 66 ... interface, 7
0 ... Storage device, 72 ... Output device, 74 ... Input device, 50 ... Black nozzle module, 5
2 ... Yellow nozzle module, 54 ... Magenta nozzle module, 56 ... Cyan nozzle module, S ... Print medium (paper), L ... Network cable, N ... Nozzle

Claims (10)

A print head having nozzles for printing dots by discharging ink onto a medium used for printing;
Printing image data acquisition means for acquiring printing image data having image information of gradation number M (M is a natural number of M ≧ 2);
The image of the image data for printing is based on information indicating the type of image element constituting the image of the image data for printing and print density information which is information on the print density preset for each type of the image element. Print density changing means for changing the print density of
Printing means for printing the image on the medium by the print head based on the print image data after changing the print density;
The print density information is information in which the maximum print density of the image element whose type belongs to a character is set to a print density higher than the maximum print density of an image element whose type belongs to other than a character. Printing device to do. The print density changing unit is configured to change the print image data based on the print density information and the background density when the image of the print image data includes an image element belonging to a character whose type has a background. The printing apparatus according to claim 1, wherein a printing density of an image element portion belonging to the character having the background in the image is changed. The print density information is a color conversion information table used for color conversion processing of the image data for printing set for each type of the image element,
2. The print density changing unit is configured to change a print density of an image of the print image data based on the color conversion information table during a color conversion process on the print image data. Item 3. The printing apparatus according to Item 2. The print density changing unit is configured to perform color conversion processing before or after color conversion processing of the printing image data.
The printing apparatus according to claim 1, wherein the printing density changing process is executed on the printing image data. The print density information is a process of converting image information of the number of gradations M of the print image data set for each type of image element into image information of the number of gradations N (M ≧ N ≧ 2). It is threshold information used for a certain N-value process,
2. The print density changing unit is configured to change a print density of an image of the print image data based on the threshold information during an N-value process for the print image data. Item 3. The printing apparatus according to Item 2. A printing apparatus control program for controlling a printing apparatus having a print head having a nozzle for ejecting ink onto a medium used for printing to print dots,
A printing image data acquisition step of acquiring printing image data having image information of the number of gradations M (M is a natural number of M ≧ 2);
The image of the image data for printing is based on information indicating the type of image element constituting the image of the image data for printing and print density information which is information on the print density preset for each type of the image element. A print density change step for changing the print density,
Including a program used to cause a computer to execute a process including a printing step of printing the image on the medium by the print head based on the print image data after changing the print density,
The print density information is information in which the maximum print density of the image element whose type belongs to a character is set to a print density higher than the maximum print density of an image element whose type belongs to other than a character. Printer control program to run. A printing apparatus control method for controlling a printing apparatus having a print head having a nozzle for ejecting ink onto a medium used for printing to print dots,
A printing image data acquisition step of acquiring printing image data having image information of the number of gradations M (M is a natural number of M ≧ 2);
The image of the image data for printing is based on information indicating the type of image element constituting the image of the image data for printing and print density information which is information on the print density preset for each type of the image element. A print density change step for changing the print density,
A printing step of printing the image on the medium by the print head based on the print image data after changing the print density,
The print density information is information in which the maximum print density of the image element whose type belongs to a character is set to a print density higher than the maximum print density of an image element whose type belongs to other than a character. To control printing apparatus. Printing image data acquisition means for acquiring printing image data having image information of gradation number M (M is a natural number of M ≧ 2);
The image of the image data for printing is based on information indicating the type of image element constituting the image of the image data for printing and print density information which is information on the print density preset for each type of the image element. Printing density changing means for changing the printing density of
The print density information is information in which the maximum print density of the image element whose type belongs to a character is set to a print density higher than the maximum print density of an image element whose type belongs to other than a character. An image processing apparatus. A printing image data acquisition step of acquiring printing image data having image information of the number of gradations M (M is a natural number of M ≧ 2);
The image of the image data for printing is based on information indicating the type of image element constituting the image of the image data for printing and print density information which is information on the print density preset for each type of the image element. A program used to cause a computer to execute a process having a print density change step for changing the print density of
The print density information is information in which the maximum print density of the image element whose type belongs to a character is set to a print density higher than the maximum print density of an image element whose type belongs to other than a character. Image processing program. A printing image data acquisition step of acquiring printing image data having image information of the number of gradations M (M is a natural number of M ≧ 2);
The image of the image data for printing is based on information indicating the type of image element constituting the image of the image data for printing and print density information which is information on the print density preset for each type of the image element. A print density changing step for changing the print density of
The print density information is information in which the maximum print density of the image element whose type belongs to a character is set to a print density higher than the maximum print density of an image element whose type belongs to other than a character. Image processing method.

Images