JP4720123B2 - Print control apparatus, print control method, and print control program - Google Patents

Description

  The present invention relates to a technique for regulating the total amount of ink when an image composed of halftone dots is printed.

  Ordinary printed matter is often formed using halftone dots. On the other hand, in recent years, color printers for general-purpose computers such as personal computers and workstations are becoming popular. Although such a color printer has a good image quality despite its relatively low price, there is a demand for creating a proof (printed material for proofreading) of a printed matter using such a color printer. Since the proof is for confirming the finish of the printed material, it is preferable that the proof is printed using the same halftone dots as the printed material.

  With reference to FIG. 11, the principle of causing a color printer to form a halftone image will be described. FIG. 11A is a diagram showing a threshold matrix used for forming a halftone image, and FIG. 11B is a schematic diagram showing halftone dots printed in a color printer. The threshold value matrix shown in FIG. 11A is for binarizing the pixel density (0-255) represented by 8 bits, and the numerical value described in each element of the threshold value matrix indicates the threshold value. To express. A pixel corresponding to an element of the threshold matrix is set to “on (dot generation)” if the pixel density of the pixel is equal to or higher than the threshold, and is set to “off (no dot generation)” if the pixel density is less than the threshold. . The general-purpose computer binarizes the pixel density of the image data on and off using this threshold matrix, and outputs it to the color printer.

  As shown in FIG. 11A, the threshold value matrix used for causing the color printer to print a halftone image is set so that the value increases from the center toward the outer periphery. As shown in (b), dots are concentrated at or near the center of the screen cell, and a halftone dot having a size corresponding to the pixel density is formed.

  By the way, depending on the type of recording paper, a larger amount of ink than the amount of ink that can be absorbed by the recording paper is attached, so that the ink becomes excessive and the recording paper becomes wet. Occurs. In order to prevent such a problem, the upper limit of the pixel density is restricted before binarization to regulate the total amount of ink.

  With reference to FIG. 12, a process for regulating the total amount of ink will be described. FIG. 12 is a flowchart showing a conventional print data output process for outputting print data for printing a halftone image to a color printer. According to this print data output processing, first, color adjustment processing such as color matching processing is performed on the input image data (S101). Next, in the ink amount adjustment process, a process of multiplying the pixel density output as a result of the color adjustment process by an ink regulation value (for example, 0.8) is performed. That is, if the pixel density output as a result of the color adjustment process is in the range of “0-255”, the pixel density range is limited to “0-204” by multiplying by “0.8” (S102). ). Subsequently, as a result of the ink amount adjustment process, the limited pixel density is binarized on and off using the threshold matrix (S103), and the result is output to the printer (S104).

  With reference to FIG. 13, halftone dots formed in the color printer as a result of the processing shown in FIG. 12 will be described. FIG. 13 is a diagram showing a comparison between a halftone dot where the total ink amount is not regulated and a halftone dot where the total ink amount is regulated, and (a) is output as a result of the color adjustment process (S101 in FIG. 12). The halftone dots formed when the pixel densities are all “255” and the total ink amount is not regulated, and (b) shows the state where the total ink amount of the halftone dots shown in (a) is regulated to 80%. FIG. That is, in the ink amount adjustment process (S102 in FIG. 12), the upper limit value “255” of the pixel density is limited to “204”, so that the pixels constituting the outer periphery of the halftone dot are dot-off by binarization. Therefore, the size of the halftone dots to be formed is reduced, and it is possible to prevent ink from adhering beyond the amount that can be absorbed by the recording paper. Further, (c) shows halftone dots formed when the values outputted as a result of the color adjustment processing are all “160” in the screen cell, and (d) shows the total ink amount of the halftone dots shown in (c). It is a figure which shows the state by which 80% was controlled. That is, in order to obtain the uniformity of the density of the entire image, all the pixel densities are multiplied by the ink adjustment amount “0.8”, and are limited at the same rate.

  FIG. 14 is a diagram showing a state in which a plurality of dots shown in FIG. 13B are continuously formed. Originally, an area where all the values output as a result of the color adjustment process (S101 in FIG. 12) are “255” is a solid area, so it is desirable that no blank is generated between the halftone dots. However, if the diameter of each halftone dot is reduced in order to restrict the ink amount to 80%, there is a problem that a blank that cannot be ignored is generated between the halftone dots.

  In order to solve such problems, Japanese Patent Application Laid-Open No. 10-1000047 (Patent Document 1) preliminarily determines dots to be turned off among dots constituting a halftone dot, and regulates the ink amount. In some cases, a technique is disclosed in which the predetermined dots are not recorded. FIG. 15A shows halftone dots in which the values output as a result of the color adjustment process (S101 in FIG. 10) are all “255” and the total amount of ink is not regulated, and FIG. 15B shows the total amount of ink. A halftone dot restricted to 80% is shown, and (c) shows a halftone dot restricted to a total ink amount of 50%.

Also, FIG. 16A shows halftone dots formed when the values output as a result of the color adjustment process (S101 in FIG. 10) are all “160” and the total amount of ink is not regulated, and FIG. Indicates a halftone dot formed when the total amount of ink is restricted to 80%, and (c) shows a halftone dot formed when the total amount of ink is restricted to 50%. In this way, the total amount of ink can be regulated by turning off dots according to the total amount of ink. Furthermore, in general, in an ink-jet printer, dots spread more than a predetermined square, so that the area that has been turned off is also almost filled with adjacent dots, so that there is no visually large space.
Japanese Patent Application Laid-Open No. 10-1000047

  However, when the diameter of each dot constituting the halftone dot is not so large, there is a problem in that the area where the dot is off is not filled with the adjacent dot, and a blank portion is generated inside the halftone dot. Further, as shown in FIGS. 15 (c) and 16 (c), when the total amount of ink is regulated to 50%, the dots are alternately turned on and off. In order to regulate the total amount of ink beyond this, In this case, there is a continuous portion of the area where the dots are turned off. However, in this case, there is a high possibility that a blank having a size that cannot be ignored visually is generated inside the halftone dot. Further, when the dots that constitute the outermost periphery of a halftone dot are turned off, there is a problem that the outline of the halftone dot is deformed and the halftone image becomes dirty as a whole as shown in FIG. It was.

  The present invention has been made to solve the above-described problems, and is a case where the total amount of ink is regulated according to the type of recording paper when a dot-concentrated halftone image is printed by a printing unit. Another object of the present invention is to provide a print control apparatus, a print control method, and a print control program capable of regulating the total amount of ink while suppressing the generation of blanks and the deformation of halftone dot outlines.

In order to achieve this object, the printing control apparatus according to claim 1 is connected to printing means capable of forming a plurality of types of dots having different dot diameters on the recording paper according to the ink amount, and print data is connected to the printing means. The dot concentration type halftone dot image is printed by the printing means, the ink restriction value obtaining means for obtaining the ink restriction value for restricting the total amount of ink, the input image signal, and the halftone dot A comparison means for comparing a threshold value matrix preliminarily storing threshold values for determining whether or not to record each pixel in a screen cell composed of a plurality of pixels of the screen, and as a result of the comparison by the comparison means, for each pixel that is not the kind of dot diameter a respective pixel is determined to record the dots yet determined, it is obtained by the ink regulation value acquiring means Ink restricted in the screen cell comprising the plurality of pixels, the dot type determining means for determining which of the plurality of types of dots having different dot diameters is to be formed using the ink regulation value of the total amount so that the total amount of the ink corresponding to the ink regulation value, the Kakue element determined to print dots within the screen cell, any dots among the plurality of types of dot diameters are different dots wherein said dot type determination means for determining whether to form, comparison result from the comparing means, the type of dot diameter, which is determined by the dot type determination means for Kakue arsenide and the pixel which is determined to record dots Output means for outputting to the printing means as print data.

The print control apparatus according to claim 2, wherein the printing unit is configured to be capable of forming at least three types of dots having different dot diameters on a recording sheet, and the dot type determination unit. the kind of dot diameter to be formed for Kakue element that is determined to record dots of plural pixels in the screen cell, one of two dot diameters the order of magnitude of the dot diameter are adjacent to one another It will be decided.

  The print control apparatus according to claim 3, further comprising: a random number acquisition unit that acquires a random number for each pixel determined to record a dot by the comparison unit according to claim 1, wherein the dot The type determining means compares the random number acquired by the random number acquiring means with a value based on the ink restriction value acquired by the ink restriction value acquisition means to determine which kind of dot is to be formed. It is determined for each pixel. Note that the value based on the ink regulation value includes the ink regulation value itself.

  The print control apparatus according to claim 4, wherein the print control apparatus according to claim 1, further comprising: a sequence storage unit that stores a set of values corresponding to each pixel in the screen cell, and determines the dot type. The means compares the value stored corresponding to each pixel in the number sequence storage means with the value based on the ink restriction value acquired by the ink restriction value acquisition means to form any kind of dot. This is determined for each pixel. Note that the value based on the ink regulation value includes the ink regulation value itself.

  According to a fifth aspect of the present invention, in the print control apparatus according to any one of the first to fourth aspects, the dot type determining means is configured to control ink that is regulated in a predetermined plurality of screen cells existing in a group. The type of dot diameter is determined for each pixel of the predetermined plurality of screen cells so that the total amount becomes the total amount of ink corresponding to the ink restriction value acquired by the ink restriction value acquisition means. Is.

7. The print control method according to claim 6, wherein the print data is output to a printing unit capable of forming a plurality of types of dots having different dot diameters on the recording paper in accordance with the ink amount, and a dot-concentrated halftone image is printed on the printing unit. Is a print control method that regulates the total amount of ink that adheres to the recording paper within a predetermined area, the image signal being input and each pixel in a screen cell comprising a plurality of pixels of a halftone screen. A comparison step of comparing a threshold value matrix that preliminarily stores a threshold value that determines whether or not to record, and a result of comparison by the comparison step, each pixel determined to record a dot in the screen cell type of diameter for each pixel not yet been determined, using the ink regulation value for regulating the total amount of the ink, among the dot diameter is different types of dots A dot type determining step for determining whether to form a misaligned dot, wherein the total amount of ink regulated in the screen cell comprising the plurality of pixels is the total amount of ink corresponding to the ink regulation value; for Kakue element that is determined to record dots in the screen cell, and the dot type determination step of determining whether the dot diameter to form any dots of the different types of dots, the comparison by the comparing step results, and an output step of outputting the type of dot diameter, which is determined by the dot type determination step for Kakue and boron pixels which are determined for scoring dots on the printing means as the print data.

The print control method according to claim 7 is the print control method according to claim 6, wherein the printing unit is configured to be capable of forming at least three types of dots having different dot diameters on a recording sheet, and the dot type determination step. It is a type of dot diameter to be formed for Kakue element that is determined to record dots of plural pixels in the screen cell, one of two dot diameters the order of magnitude of the dot diameter are adjacent to each other It will be decided.

  The print control method according to claim 8, further comprising: a random number acquisition step of acquiring a random number for each pixel determined to record a dot by the comparison step in the print control method according to claim 6, wherein the dot In the type determination step, the random number acquired in the random number acquisition step is compared with a value based on the ink regulation value to determine which type of dot is formed for each pixel. Note that the value based on the ink regulation value includes the ink regulation value itself.

  The print control method according to claim 9 is the print control method according to claim 6 or 7, wherein the dot type determination step includes a preset value corresponding to each pixel in the screen cell and the ink restriction. A value based on the value is compared to determine which type of dot is to be formed for each pixel. Note that the value based on the ink regulation value includes the ink regulation value itself.

  The print control method according to claim 10 is the print control method according to any one of claims 6 to 9, wherein the dot type determination step is performed for an ink that is regulated in a predetermined plurality of screen cells existing in a group. The type of dot diameter is determined for each pixel of the predetermined plurality of screen cells so that the total amount becomes the total amount of ink corresponding to the ink regulation value.

The print control program according to claim 11 is connected to a printing means capable of forming a plurality of types of dots having different dot diameters on the recording paper in accordance with the ink amount, outputs print data to the printing means, and is a dot concentration type. It is executed by a computer that prints a halftone image by the printing means, and an ink regulation value that regulates the total amount of ink attached to the recording paper within a predetermined area is acquired according to the type of the recording paper. Comparison that compares the ink regulation value acquisition means with the input image signal and a threshold matrix that prestores thresholds for determining whether or not to record each pixel in a screen cell composed of a plurality of pixels of a halftone screen. means the result of the comparison by the comparing means, the type of dot diameter a respective pixel is determined to record the dots within the screen cell yet determined For each pixel have, by using the ink regulation value acquired by the ink regulating value obtaining unit, a dot type determination means for determining whether the dot diameter to form any dots of the different types of dots there, the so amount of ink is regulated in the screen cell comprising a plurality of pixels is equal to the total amount of the ink corresponding to the ink regulation value, the Kakue element determined to print dots within the screen cell , the dot type determining means, the result of comparison by the comparing means, Kakue arsenide and the pixel which is determined to record dots to determine whether to form either dots among the plurality of types of dot diameters are different dots The type of dot diameter determined by the dot type determination unit is output to the printing unit as the print data An output unit that causes the computer to function.

The print control program according to claim 12 is the print control program according to claim 11, wherein the printing unit is configured to be able to form at least three types of dots having different dot diameters on a recording sheet, and the dot type determining unit. It is a type of dot diameter to be formed for Kakue element that is determined to record dots of plural pixels in the screen cell, in either of the two dot diameters that are adjacent to each other in the order of magnitude of the dot diameter To decide.

  A print control program according to a thirteenth aspect of the invention is the print control program according to the eleventh or twelfth aspect, causing the computer to function as a random number acquisition unit that acquires a random number for each pixel determined to record dots by the comparison unit. The dot type determination unit compares the random number acquired by the random number acquisition unit with the value based on the ink regulation value acquired by the ink regulation value acquisition unit, and forms any type of dot. This is determined for each pixel. Note that the value based on the ink regulation value includes the ink regulation value itself.

  The print control program according to claim 14 is the print control program according to claim 11 or 12, causing the computer to function as a sequence storage unit that stores a set of values corresponding to each pixel in the screen cell, and The dot type determining means compares the value stored corresponding to each pixel in the number sequence storage means with the value based on the ink restriction value acquired by the ink restriction value acquisition means, and Whether to form dots is determined for each pixel. Note that the value based on the ink regulation value includes the ink regulation value itself.

  The print control program according to claim 15 is the print control program according to any one of claims 11 to 14, wherein the dot type determining means is configured to control ink that is regulated in a predetermined plurality of screen cells. The type of dot diameter is determined for each pixel of the predetermined plurality of screen cells so that the total amount becomes the total amount of ink corresponding to the ink restriction value acquired by the ink restriction value acquisition means. Is.

  According to the printing control apparatus of claim 1, the print data is output to a printing unit capable of forming a plurality of types of dots having different dot diameters according to the ink amount on the recording paper, and the dot-concentrated halftone image is Printed by printing means. Here, the ink regulation value for regulating the total amount of ink is acquired by the ink regulation value acquisition means. Also, the comparison unit compares the input image signal with a threshold matrix that prestores thresholds for determining whether or not to record each pixel in a screen cell composed of a plurality of pixels of a halftone screen. As a result, for the pixels determined to record dots in the screen cell, the dot type determining means uses the ink restriction value acquired by the ink restriction value acquisition means, and the dot type is different from the plural types of dots having different dot diameters. It is determined whether to form dots. Then, as a result of comparison by the comparison unit, the pixel determined to record a dot and the type of dot diameter determined by the dot type determination unit for the pixel are output to the printing unit by the output unit as print data.

  Therefore, in the printing unit, as a result of the comparison with the threshold matrix, for the pixels determined to record the dots in the screen cell, the dots of the diameter type determined using the ink regulation value that regulates the total amount of ink are printed. As a result, the total amount of ink can be regulated. Also, as a result of comparison with the threshold values stored in the threshold value matrix, dots that are determined to be recorded are formed regardless of the ink regulation value, so blank portions that are difficult to ignore visually are halftone dots. There is an effect that it is suppressed to occur in the interior of the. Further, as compared with a case where a predetermined number of dots are turned off in order to regulate the total amount of ink, the contour of the halftone dot is not deformed, so that there is an effect that the image quality of the whole halftone dot image is improved. Further, there is an effect that the total amount of ink can be regulated to less than 50%. That is, in the technique of turning off the dots in order to regulate the total amount of ink, if the total amount of ink is to be regulated to less than 50%, an area where the dots are turned off exists adjacently in the halftone dots. Since a blank portion that is difficult to ignore visually occurs, the total amount of ink could not be further controlled.

  According to a second aspect of the printing control apparatus, in addition to the effect of the first aspect of the printing control apparatus, the printing unit is configured to be able to form at least three types of dots having different dot diameters on the recording paper. The dot type determining means determines the type of the dot diameter formed for the pixel determined to record the dot from the plurality of pixels in the screen cell, and the two types of dots whose dot diameter order is adjacent to each other. Since it is determined as one of the diameters, there is an effect that the overall image quality of the halftone image printed by the printing means is improved. If dots with extremely large dot diameters are mixed in one halftone dot, the image may become dirty due to noise.

  According to the print control apparatus of claim 3, in addition to the effect produced by the print control apparatus of claim 1 or 2, random number acquisition means for acquiring a random number for each pixel determined to record dots by the comparison means The dot type determination means compares the random number acquired by the random number acquisition means with a value based on the ink restriction value acquired by the ink restriction value acquisition means, and determines which type of dot Is determined for each pixel, so that different types of dots are mixed evenly, and there is an effect that the viewer who sees the halftone image does not feel uncomfortable.

  According to the print control apparatus of the fourth aspect, in addition to the effect produced by the print control apparatus of the first or second aspect, there is provided a sequence storage means for storing a set of values corresponding to each pixel in the screen cell. The dot type determination means compares the value stored in correspondence with each pixel in the number sequence storage means and the value based on the ink restriction value acquired by the ink restriction value acquisition means, Since it is determined for each pixel whether or not this kind of dot is to be formed, the processing for determining the dot diameter is easy and the processing speed is improved.

  According to the printing control apparatus of claim 5, in addition to the effect produced by the printing control apparatus according to any one of claims 1 to 4, the dot type determination means includes a plurality of predetermined screen cells existing in a group. For each pixel of the predetermined plurality of screen cells so that the total amount of ink regulated in step S1 is the total amount of ink corresponding to the ink regulation value acquired by the ink regulation value acquisition unit. Since the type of diameter is determined, even if the total amount of ink in a single screen cell cannot be the total amount of ink corresponding to the ink regulation value, the total amount of ink regulated in a plurality of screen cells is The total amount of ink corresponding to the ink regulation value should be regulated so that the total amount of ink corresponds to the ink regulation value when viewed globally. There is an effect that can be.

  According to the print control method of the sixth aspect, the print data is output to a printing unit capable of forming a plurality of types of dots having different dot diameters according to the ink amount on the recording paper, and the dot-concentrated halftone image is Printed by printing means. Here, the input image signal is compared with a threshold value matrix that prestores threshold values for determining whether or not to record each pixel in the screen cell composed of a plurality of pixels of the halftone screen, and the comparison process compares the image signal. As a result of the comparison, for the pixels that are determined to be recorded in the screen cell, the dot type determination step forms any dot among a plurality of types of dots with different dot diameters using an ink regulation value that regulates the total amount of ink. It is decided whether to do. Then, as a result of the comparison in the comparison step, the pixel determined to record the dot and the dot diameter type determined in the dot type determination step for the pixel are output to the printing unit as print data by the output unit.

  Therefore, in the printing unit, as a result of the comparison with the threshold matrix, for the pixels determined to record the dots in the screen cell, the dots of the diameter type determined using the ink regulation value that regulates the total amount of ink are printed. As a result, the total amount of ink can be regulated. Also, as a result of comparison with the threshold values stored in the threshold value matrix, dots that are determined to be recorded are formed regardless of the ink regulation value, so blank portions that are difficult to ignore visually are halftone dots. There is an effect that it is suppressed to occur in the interior of the. Further, as compared with a case where a predetermined number of dots are turned off in order to regulate the total amount of ink, the contour of the halftone dot is not deformed, so that there is an effect that the image quality of the whole halftone dot image is improved. Further, there is an effect that the total amount of ink can be regulated to less than 50%. That is, in the technology for turning off the dots in order to regulate the total amount of ink, when trying to regulate the total amount of ink to less than 50%, pixels in which the dots are turned off exist adjacently in the halftone dots. Since a blank portion that is difficult to ignore visually occurs, the total amount of ink could not be further controlled.

  According to the print control method of claim 7, in addition to the effect of the print control method of claim 6, the printing unit is configured to be able to form at least three types of dots having different dot diameters on the recording paper. In the dot type determining step, the types of the dot diameters formed for the pixels determined to record the dots among the plurality of pixels in the screen cell are determined by using the two types of dots adjacent to each other in the order of the dot diameters. Since it is determined as one of the diameters, there is an effect that the overall image quality of the halftone image printed by the printing means is improved. If dots with extremely large dot diameters are mixed in one halftone dot, the image may become dirty due to noise.

  According to the printing control method according to claim 8, in addition to the effect exerted by the printing control method according to claim 6 or 7, a random number acquisition step of acquiring a random number for each pixel determined to record dots by the comparison step The dot type determination step determines for each pixel which type of dot is to be formed by comparing the random number acquired in the random number acquisition step with a value based on the ink regulation value. Therefore, different types of dots are mixed evenly, and there is an effect that the viewer who sees the halftone image does not feel uncomfortable.

  According to the printing control method according to claim 9, in addition to the effect produced by the printing control method according to claim 6 or 7, a value set in advance corresponding to each pixel in the screen cell and the ink regulation value Since it is determined for each pixel which type of dot is to be formed by comparing with the value based on the above, there is an effect that the processing for determining the dot diameter is easy and the processing speed is improved.

  According to the printing control method of claim 10, in addition to the effect produced by the printing control method according to any of claims 6 to 9, the dot type determination step includes a predetermined plurality of screen cells existing in a group. Since the type of dot diameter is determined for each pixel of the predetermined plurality of screen cells so that the total amount of ink regulated in step S1 becomes the total amount of ink corresponding to the ink regulation value, Even when the total amount of ink in the screen cell cannot be the total amount of ink corresponding to the ink regulation value, the total amount of ink regulated in the plurality of screen cells is the total amount of ink corresponding to the ink regulation value. The total amount of ink corresponding to the ink regulation value can be obtained when viewed globally.

  The print control program according to claim 11 is executed by a computer to output print data to a printing means capable of forming a plurality of types of dots having different dot diameters on the recording paper according to the amount of ink. The computer is caused to function so that a centralized halftone image is printed by the printing means. The printing unit is connected to the computer. Further, an ink regulation value that regulates the total amount of ink is acquired, and an input image signal and a threshold value for determining whether to record each pixel in a screen cell composed of a plurality of pixels of a halftone screen are stored in advance. The threshold matrix is compared, and as a result of the comparison, for the pixel determined to record the dot in the screen cell, any one of a plurality of types of dots having different dot diameters is formed using the ink regulation value. As a result of the comparison, the computer is caused to function so as to output the pixel determined to record the dot and the type of the dot diameter determined for the pixel to the printing unit as print data.

  Therefore, in the printing unit, as a result of the comparison with the threshold matrix, for the pixels determined to record the dots in the screen cell, the dots of the diameter type determined using the ink regulation value that regulates the total amount of ink are printed. As a result, the total amount of ink can be regulated. Also, as a result of comparison with the threshold values stored in the threshold value matrix, dots that are determined to be recorded are formed regardless of the ink regulation value, so blank portions that are difficult to ignore visually are halftone dots. There is an effect that it is suppressed to occur in the interior of the. Further, as compared with a case where a predetermined number of dots are turned off in order to regulate the total amount of ink, the contour of the halftone dot is not deformed, so that there is an effect that the image quality of the whole halftone dot image is improved. Further, there is an effect that the total amount of ink can be regulated to less than 50%. That is, in the technology for turning off the dots in order to regulate the total amount of ink, when trying to regulate the total amount of ink to less than 50%, pixels in which the dots are turned off exist adjacently in the halftone dots. Since a blank portion that is difficult to ignore visually occurs, the total amount of ink could not be further controlled.

  According to the printing control program of the twelfth aspect, in addition to the effect of the printing control program according to the eleventh aspect, the printing unit is configured to be able to form at least three types of dots having different dot diameters on the recording paper. The type of the dot diameter formed for the pixel determined to record the dot among the plurality of pixels in the screen cell is determined as one of two types of dot diameters adjacent to each other in the order of the dot diameter size. Thus, the computer is caused to function. Therefore, there is an effect that the overall image quality of the halftone image printed by the printing means is improved. If dots with extremely large dot diameters are mixed in one halftone dot, the image may become dirty due to noise.

  According to the print control program of claim 13, in addition to the effect produced by the print control program of claim 11 or 12, a random number is acquired for each pixel determined to record dots by the comparison means, and the acquisition The computer is caused to function so as to determine for each pixel which type of dot is to be formed by comparing the random number thus generated and a value based on the ink regulation value. Therefore, different types of dots are mixed evenly, and there is an effect that the viewer who sees the halftone image does not feel uncomfortable.

  According to the print control program of claim 14, in addition to the effect produced by the print control program according to claim 11 or 12, a set of values corresponding to each pixel in the screen cell is stored and stored. The computer is caused to function so as to determine for each pixel which type of dot is formed by comparing the value with a value based on the ink regulation value. Therefore, the processing for determining the dot diameter in the computer is easy, and the processing speed is improved.

  According to the print control program according to claim 15, in addition to the effect produced by the print control program according to any one of claims 11 to 14, the total amount of ink regulated in a predetermined plurality of screen cells existing in a group. However, the computer is caused to function so as to determine the type of dot diameter for each pixel of a predetermined plurality of screen cells so that the total amount of ink corresponding to the ink regulation value is obtained. Therefore, even if the total amount of ink in a single screen cell cannot be the total amount of ink corresponding to the ink regulation value, the total amount of ink regulated in the plurality of screen cells corresponds to the ink regulation value. There is an effect that the total amount of ink can be regulated to be the total amount of ink corresponding to the ink regulation value when viewed globally.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing a schematic configuration of a personal computer 2 (PC 2) which is a print control apparatus of the present invention. As shown in FIG. 1, the PC 2 includes a central processing unit (CPU) 12, a ROM 13, a RAM 14, a random number generator 15, a hard disk drive (HDD) 16, and an I / O port 17. Are connected by a bus line B so that control signals and data signals can be exchanged. Further, an input / output device such as a keyboard 21 and a display 22, a printing device 24, and an external storage device 25 are connected to the PC 2 via the I / O port 17.

  The ROM 13 is a non-volatile memory, and includes a program memory 13a and a recording paper type table 13b. The program memory 13a stores a basic program for performing writing control after the PC 2 is turned on, a print data output processing program, a screen generation / ink amount adjustment processing program, and other processing programs to be described later. And executed by the CPU 12. The program is executed by reading from a storage medium such as a flexible disk, a magneto-optical disk, or a CD-ROM in which the various programs are stored into the working memory 14f as necessary via the external storage device 25. Also good.

  The recording paper type table 13b is a table in which the type of dot diameter and the ink regulation value T are associated with the type of recording paper. The “type of dot diameter” is the type of dot diameter to be used for the recording paper. For recording papers for which the total amount of ink is desired to be significantly restricted, two types of medium dots and small dots are associated with each other, and for recording papers that do not require a significant restriction on the total amount of ink. In this case, two types of large dots and medium dots are associated with each other. The “ink regulation value T” is a value for determining the existence probability of two types of dots associated as “type of dot diameter” according to the type of recording paper.

  The RAM 14 temporarily stores data and programs necessary for various processes executed by the CPU 12, and includes a threshold matrix storage memory 14a, a dot type memory 14b, an ink regulation value memory 14c, and an input image data memory. 14d, a print data memory 14e, and a working memory 14f.

  The threshold value matrix storage memory 14a is a memory that stores, as a threshold value matrix, threshold values that determine whether or not to record each pixel in a screen cell composed of 8 × 8 pixels. The dot type memory 14b is a memory for storing two types of dot diameters used for printing a halftone image. Based on the type of recording paper input by the user, by referring to the recording paper type table 13b, values indicating two types of dot diameters to be used for the recording paper are acquired, and the acquired values Is written into the dot seed memory 14b.

  The ink regulation value memory 14c is a memory that stores an ink regulation value T for determining the existence probability of two types of dots stored in the dot type memory 14b. Based on the type of recording paper input by the user, the ink regulation value T associated with the recording paper is obtained by referring to the recording paper type table 13b, and the obtained value is the ink regulation value. It is written into the value memory 14c.

  The input image data memory 14d is introduced from the external storage device 25 and stores the input image data after color adjustment processing is performed. The pixel density range of this input image data is 0-255. The print data memory 14e stores print data created based on the input image data memory 14d. The print data is output to the printing device 24, and the printing device 24 prints a dot-concentrated halftone image based on the print data.

  The working memory 14f is for temporarily storing data required when the CPU 12 executes the program stored in the program memory 13a, or for placing and starting the loaded program.

  The random number generator 15 has a function of generating a random number of 0.0 to 1.0. The frequency characteristics of the random numbers generated here may be white noise or blue noise. Usually, it is sufficient to use a function (for example, an rnd function) prepared for generating pseudorandom numbers on a computer.

  The printing device 24 is an ink jet printer that performs printing by ejecting ink droplets and attaching them to a recording paper. By controlling the amount of ejected ink droplets, large dots, medium dots, Three types of small dots can be formed on the recording paper. FIG. 2 is a diagram illustrating a state where large dots, medium dots, small dots, and no dots that can be formed by the printing apparatus 24 are illustrated. As shown in FIG. 2, the dot diameter decreases in the order of large dots, medium dots, and small dots, and the amount of ink used decreases in this order.

  Next, the principle of forming a dot-concentrated halftone image will be described with reference to FIG. FIG. 3A shows an 8 × 8 threshold matrix for binarizing the pixel density so as to form a halftone dot, and the numerical value written in each pixel represents the threshold. (B) is a diagram schematically showing input image data, and a numerical value described in an enlarged pixel represents the pixel density. The threshold value matrix shown in (a) is superimposed on the input image data, and the threshold value is compared with the pixel density of each corresponding pixel. When the pixel density of the input image data is larger, the dot is on, and when it is smaller, the dot is off. Binarize. After the processing of 8 × 8 pixels of input image data (hereinafter, this unit is referred to as a screen cell), the threshold matrix is sequentially moved to the next screen cell, and the same processing is repeated. Here, as shown in FIG. 3A, in the threshold matrix, the threshold is set so that the value increases from the center toward the outer periphery, so that the dots are concentrated at the center or near the center of the screen cell. A halftone dot having a size corresponding to the pixel density is formed.

  Next, a method for regulating the total amount of ink attached to the recording paper within a predetermined area to an amount corresponding to the type of recording paper will be described with reference to FIG. FIGS. 4A and 4B are diagrams schematically showing halftone dots formed corresponding to screen cells having a pixel density of “160”. FIG. 4A shows a case where the total amount of ink is not regulated, and FIG. It is a figure which shows the case where a total amount is controlled by 80%, (c) is a figure which shows the case where the total amount of ink is controlled by 50%.

  As shown in FIGS. 4A to 4C, when all the pixel densities in the screen cell are “160”, a halftone dot having a predetermined size corresponding to the pixel density “160” is formed. Here, in FIG. 4A, halftone dots are configured with large dots, whereas when the total amount of ink is restricted to 80%, the halftone dots are configured as shown in FIG. 4B. The medium dots are included in the dots to be performed with a predetermined probability based on the ink regulation value T. When the total amount of ink is regulated to 50%, as shown in FIG. 4C, the halftone dot is composed of medium dots and small dots, and the medium dots and small dots are further based on the ink regulation value T. Exist with a certain probability. Since medium dots and small dots are formed with a small amount of ink compared to large dots, the total amount of ink can be set to a desired value by making medium dots or small dots exist with a predetermined probability based on the ink regulation value. It can be regulated.

  Next, print data output processing executed by the CPU 12 will be described with reference to FIG. FIG. 5 is a flowchart of the print data output process. This process is a process for creating print data for forming a halftone image and outputting it to the printing apparatus 24. The print data output process is started when a predetermined operation is performed from the keyboard 21. In addition, prior to the print data output process, the type of recording paper is input in advance.

  In this print data output process, first, by referring to the recording paper type table 13b, the type of dot diameter and the ink regulation value T corresponding to the type of recording paper input in advance are acquired, and the dot type memory 14b and the ink are stored. Each value of the regulation value memory 14c is updated (S1).

  Here, if the recording paper is required to restrict the total amount of ink to 80%, the recording paper type table 13b is referred to, for example, the dot diameter type is acquired as a large dot or a medium dot. As a result, “0.67” is acquired as the ink regulation value T.

  Next, the image data introduced from the external storage device or the like is subjected to predetermined color adjustment processing such as color matching processing and stored in the input image data memory 14d (S2). Next, screen generation / ink amount adjustment processing, which will be described later, is performed on the input image data stored in the input image data memory 14d, print data is created, and stored in the print data memory 14e (S3). Then, the print data stored in the print data memory 14e is output to the printing device 24 (S4, output process).

  Next, the screen generation / ink amount adjustment process shown in S3 of FIG. 5 will be described with reference to the flowchart of FIG. Note that this process starts with one pixel at the position where the main scanning direction position and the sub-scanning direction position of the input image data are the smallest as the first target pixel, and sequentially moves the target pixel in the main scanning direction or the sub-scanning direction. This is performed for all the pixels constituting the input image data.

  In this screen generation / ink amount adjustment processing, first, a threshold matrix is read from the HDD 16 or the external storage device 25, and this is read into the threshold matrix storage memory 14a (S31).

  Next, the pixel density of the target pixel of the input image data stored in the input image data memory 14d is compared with the threshold value of the threshold value matrix corresponding to the target pixel (S32, comparison step), and if the pixel density is greater than the threshold value. (S32: Yes), the target pixel is turned on as a binary value (S33), and if the pixel density is equal to or lower than the threshold (S32: No), the target pixel is set as a binary value (S34).

  When ON is set for the target pixel, the random number for the target pixel is read from the random number generator 15 (S35). Next, it is checked whether or not the type of dot diameter stored in the dot type memory 14b is a combination of large dots and medium dots (S36). When the types of dot diameters stored in the dot type memory 14b are large dots and medium dots (S36: Yes), the random number read in the process of S35 is the ink stored in the ink regulation value memory 14c. It is checked whether or not it is larger than the regulation value T (S37).

  When the random number read in the process of S35 is larger than the ink regulation value T (for example, 0.67) (S37: Yes), the type of the dot diameter formed corresponding to the target pixel is “large dot”. Is selected (S38). On the other hand, if the random number read in the process of S35 is equal to or less than the ink regulation value T, “medium dot” is selected as the type of dot diameter formed corresponding to the target pixel (S39).

  Subsequently, the process proceeds to the process of S43, and it is checked whether or not all the pixels of the input image data have been processed (S43). If all the pixels have been processed (S43: No), this process ends. . If there is a pixel that has not been processed (S43: Yes), the processing returns to S32, and the same processing is repeated with the pixel that has not been processed yet as the next pixel of interest.

  In the above description, the case where the dot diameter types stored in the dot type memory 14b are large dots and medium dots has been described. However, a recording sheet that is required to largely restrict the total amount of ink is selected. If so, medium dots and small dots are stored in the dot type memory 14b. In that case (S36: No), in the process of S40, the read random number is compared with the ink restriction value T stored in the ink restriction value memory 14c (S40) as in the process of S37. Is larger than the ink regulation value T (S40: Yes), “medium dot” is selected as the type of dot diameter formed corresponding to the target pixel (S41), and the random number is equal to or less than the ink regulation value T. If (S40: No), “small dot” is selected as the type of dot diameter formed corresponding to the target pixel (S42). Note that the processing from S36 to S42 shown in FIG. 6 corresponds to a dot type determination step.

  FIG. 7 shows halftone dots formed corresponding to the screen cells whose pixel densities of the input image data are all “255” as a result of the processing shown in FIGS. 5 and 6, and (a) does not regulate the total amount of ink. (B) is a diagram showing a case where the total amount of ink is regulated to 80%, and (c) is a diagram showing a case where the total amount of ink is regulated to 50%. As shown in FIG. 7, instead of turning off the dots to regulate the total amount of ink, the total amount of ink is regulated by forming halftone dots using medium dots and small dots having a smaller diameter than the large dots. Therefore, the size of the halftone dot is not so small as compared with the case where the total amount of ink is not regulated. Further, as is clear from FIGS. 7A to 7C, the contour of the halftone dot is not so deformed, so that the quality of the image is improved. Further, FIG. 7C is a diagram showing a case where the total amount of ink is restricted to 50%. However, when the total amount of ink is restricted to 50% or less, the existence probability of small dots may be increased. The total amount of ink can be regulated to 50% without forming an area for dot-off inside.

  FIG. 8 is a diagram showing a state in which a plurality of halftone dots shown in FIG. 7B are continuously formed. That is, it is a diagram illustrating a solid area to be printed (area where the pixel density of input image data is all “255”) in a state where the total amount of ink is regulated to 80%. According to the present embodiment, since there is no pixel that is dot-off, the generation of blank areas between the halftone dots or inside the halftone dots is suppressed. By using the medium dots, there may be a portion where all the dots of the dots are not filled, but the blank area is extremely small as compared with the case where the dots are turned off, and there is no visual problem.

  Next, a method for setting the ink regulation value T that is predetermined according to the type of recording paper will be described with an example. The method for setting the ink regulation value T is not limited to this method. As a precondition, the number of elements of the threshold matrix is 8 × 8 = 64, and the ratio of the appropriate amount of large dots, medium dots, and small dots formed by the printing apparatus 24 is 100: 70: 30. Further, when the total amount of ink is regulated to be less than 100% and 70% or more, large dots and medium dots are used, and when the total amount of ink is regulated to be less than 70%, medium dots and small dots are used. Dots are used.

  Under these preconditions, if the total amount of ink is not regulated, and halftone dots are formed using all large dots, the ink in the screen cell when the total amount of ink is not regulated (when the total amount of ink is 100%) The amount is set to “6400” based on the equation (1).

64 * 100 = 6400 (1)
Here, when the total ink amount is restricted to 80%, the ink amount in the screen cell is “5120” based on the equation (2).

6400 * 0.8 = 5120 (2)
When the usage ratios of large dots, medium dots, and small dots to achieve the ink amount “5120” obtained by Expression (2) are a, b, and c, respectively, Expression (3) is established.

100 * a + 70 * b + 30 * c = 5120 (3)
Further, when the total amount of ink is restricted to 80%, since large dots and medium dots are used, equation (4) is established.

a + b = 64, c = 0 (4)
By solving the equations (3) and (4), a≈21 and b≈43 can be obtained. That is, by setting the use ratio of dots in one screen cell to large dots: medium dots = 21: 43 (large dots 33%, medium dots 67%), the total amount of ink can be restricted to about 80%. Therefore, if the random number generated in the random number generator 15 is 0.0 to 1.0, the ink regulation value T is set to 0.67, and if the random number is larger than 0.67, a large dot is formed. If the random number is 0.67 or less, by setting so as to form medium dots, the appearance rates of large dots and medium dots can be set to 33% and 67%, respectively. Thus, by calculating the ink regulation value T according to the type of recording paper and storing it in the recording paper type table 13b in advance, the total amount of ink can be regulated according to the type of recording paper.

  The ink regulation value acquisition means described in claim 1 corresponds to the process of S1 in the print data output process (FIG. 5), and the comparison means corresponds to the process of S32 in the screen generation / ink amount adjustment process (FIG. 6). The processing corresponds, the dot type determination means corresponds to the processing of S37 to S42 in the screen generation / ink amount adjustment processing (FIG. 6), and the output means corresponds to the processing of S4 in the print data output processing (FIG. 5). Is applicable. The random number obtaining means according to claim 3 corresponds to the process of S36 in the screen generation / ink amount adjustment process (FIG. 6).

  Further, the ink regulation value acquisition means according to claim 11 corresponds to the process of S1 in the print data output process (FIG. 5), and the comparison means corresponds to the process of S32 in the screen generation / ink amount adjustment process (FIG. 6). The processing corresponds, the dot type determination means corresponds to the processing of S37 to S42 in the screen generation / ink amount adjustment processing (FIG. 6), and the output means corresponds to the processing of S4 in the print data output processing (FIG. 5). Is applicable. Further, the random number obtaining means according to claim 13 corresponds to the process of S36 in the screen generation / ink amount adjustment process (FIG. 6).

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various improvements and modifications can be easily made without departing from the spirit of the present invention. Can be inferred.

  For example, in this embodiment, the type of the dot diameter is determined by comparing the read random number with the ink regulation value T (S37 and S40 in FIG. 6). You may determine the kind of dot diameter by utilizing the numerical sequence memorize | stored in ROM13. FIG. 9 is a diagram showing a set of numerical values stored in advance corresponding to each pixel of an 8 × 8 screen cell. In the processes of S37 and S40 in FIG. 6, the type of dot diameter is determined based on the comparison result between the numerical values described in the elements shown in the matrix of FIG. By determining the type of the dot diameter using the numerical value stored in advance as described above, the processing for reading the random number shown in S35 of FIG. 6 becomes unnecessary, so that the processing speed can be improved.

  Further, according to the present embodiment, the ink regulation value T acquired by the ink regulation value acquisition means (S1 in FIG. 5) is a value for determining the type of dot diameter by comparing itself with a random number. However, the ink regulation value T may be a value (for example, 80%) indicating how much the total amount of ink is regulated according to the type of recording paper. In that case, based on the ink regulation value T, the dot diameter threshold value D (value based on the ink regulation value) is acquired by using, for example, the methods shown in the above-described formulas (1) to (4). In the process of determining the type of dot diameter shown in S37 and S40 of FIG. 6, the type of dot diameter is determined using the dot diameter threshold value D (value based on the ink restriction value T) instead of the ink restriction value T. You may make it do.

  In the above-described embodiment, “0.67” is acquired as the ink restriction value T for restricting the total ink amount to 80%. By uniformly applying this value, large dots and The abundance ratio of medium dots was 21:43. However, if all the halftone dots are formed with this existence ratio, the total amount of ink is “5110” from the following equation (5).

100 * 21 + 70 * 43 + 30 * 0 = 5110 (5)
As described in equation (2), in order to restrict the total ink amount to 80%, it is desirable that the ink amount be “5120”. That is, when the ink regulation value T is uniformly set to “0.67”, it can be understood that the total amount of ink in the screen cell is strictly regulated to 80% or less. Thus, although the total ink amount of each screen cell can be approximated to the desired total ink amount, it may not be able to be matched.

  Therefore, it is considered that the error generated in one screen cell with respect to the desired total amount of ink is propagated to adjacent screen cells, and the total amount of ink is regulated so as to match the desired total amount of ink when viewed globally. It is done.

  FIG. 10 is a conceptual diagram showing a screen cell, and is a diagram showing a state in which the total amount of ink is regulated so as to coincide with a desired total amount of ink when viewed globally. Here, it is assumed that 80% is set as the ink regulation value T in order to regulate the total amount of ink. The numerical value described in the upper part of each screen cell represents the dot diameter threshold D determined based on the ink regulation value T, and the numerical value described in the lower part indicates the abundance ratio of large dots and medium dots in the screen cell. ing. As shown in FIG. 10, for example, when the ink regulation value T is 80%, the dot diameter threshold D “0.67” for two screen cells out of a group (three in FIG. 10) of screen cells. ”And a dot diameter threshold D“ 0.65 ”is used for one screen cell.

  When the dot diameter threshold D is “0.67”, the abundance ratio between large dots and medium dots is 21:43, and when the dot diameter threshold D is “0.65”, the large dots and medium dots The abundance ratio is 22:42. Therefore, when the three screen cells are viewed as a group, the abundance ratio between large dots and medium dots is 64: 128. Therefore, the average of the total amount of ink in the group of screen cells is “5120” from the following equation (6).

(100 * 64 + 70 * 128 + 30 * 0) / 3 = 5120 (6)
That is, it can be seen that by using two types of dot diameter threshold values in a regular order, the total amount of ink in the group of screen cells can be regulated to match the ink regulation value T of 80%.

  Next, a method for setting the dot diameter threshold value D based on the ink regulation value T will be described with an example. When the ink regulation value T is 80%, the relationship shown in the following equation (7) is derived from the above equations (3) and (4).

100 * a + 70 * b + 30 * c = 5120 (3)
a + b = 64, c = 0 (4)
100 (64−b) = 5120 (7)
According to the equation (7), 3b = 128, and b = 42 and a solution of 2 is obtained. From the point of 3b, it can be seen that three screen cells may be used as a unit. Further, since the remainder is “2”, a combination of b = 43 and a = 21 (that is, 33% large dots and 67% medium dots) is applied to two of the three screen cells. It can be seen that a combination of b = 42 and a = 22 (that is, 35% large dots and 65% medium dots) may be applied to each screen cell. Therefore, if the random number generated in the random number generator 15 is 0.0 to 1.0, the dot diameter threshold D is set to “0.67” and “0.65”, respectively, and the random number is set to the dot diameter threshold D. If it is larger than that, a large dot is formed, and if the random number is equal to or smaller than the dot diameter threshold D, setting is made so that a medium dot is formed, whereby the total ink amount can correspond to the ink regulation value T.

  In the above-described embodiment, halftone dots are formed by combinations of large dots and medium dots, or combinations of medium dots and small dots. However, halftone dots are formed by combinations of three or more types of dots. May be.

1 is a block diagram illustrating a schematic configuration of a personal computer that is a print control apparatus of the present invention. FIG. It is a figure which shows the state of the large dot, medium dot, small dot, and no dot which can be formed with a printing apparatus. (A) is a figure which shows the 8 * 8 threshold value matrix for forming a halftone dot, and the numerical value described in each pixel represents a threshold value. (B) is a diagram schematically showing input image data, and a numerical value described in an enlarged pixel represents a pixel density. FIG. 5 is a diagram schematically showing halftone dots formed corresponding to screen cells having pixel densities of “160”, where (a) is a diagram showing a case where the total amount of ink is not regulated, and (b) is a total amount of ink. (C) is a diagram showing a case where the total amount of ink is regulated to 50%. 6 is a flowchart of print data output processing executed by a PC. 6 is a flowchart of screen generation / ink amount adjustment processing executed by a PC. FIG. 6 is a diagram showing halftone dots formed corresponding to screen cells whose input image data has a pixel density of “255”, where (a) is a diagram showing a case where the total amount of ink is not regulated, and (b) is a diagram showing ink. It is a figure which shows the case where a total amount is controlled by 80%, (c) is a figure which shows the case where the total amount of ink is controlled by 50%. FIG. 8 is a diagram showing a state in which a plurality of halftone dots shown in FIG. 7B are continuously formed. It is a figure which shows the set of the numerical value previously memorize | stored corresponding to each pixel of an 8x8 screen cell. It is a conceptual diagram showing a screen cell, and is a diagram showing a state in which the total amount of ink is regulated so as to coincide with a desired total amount of ink when viewed globally. (A) is a figure which shows the threshold value matrix used in order to form the halftone image in a prior art, (b) is the schematic which shows the halftone dot printed in a color printer. 6 is a flowchart illustrating a conventional print data output process for creating print data for printing a halftone image and outputting the print data to a color printer in the prior art. In the related art, a halftone dot in which the total amount of ink is not regulated is compared with a halftone dot in which the total amount of ink is regulated. It is a figure which shows the state in which the halftone dot shown in FIG.13 (b) is continuously formed in multiple numbers. (A) is a diagram showing halftone dots formed when all values output as a result of color adjustment processing are “255” and the total amount of ink is not regulated in the prior art, and (b) is a diagram showing ink dots. It is a figure which shows the halftone dot formed when the total amount is regulated to 80%, and (c) is a diagram showing the halftone dot formed when the total amount of ink is regulated to 50%. (A) is a diagram showing halftone dots formed when all values output as a result of color adjustment processing in the prior art are “160” and the total amount of ink is not regulated, and (b) is a total amount of ink. Is a diagram showing a halftone dot formed when the ink is regulated to 80%, and (c) is a diagram showing a halftone dot formed when the total amount of ink is regulated to 50%.

2 PC (printing control device)
13 ROM (number sequence storage means)
14a Threshold matrix storage memory 14c Ink regulation value memory 15 Random number generator 24 Printing device (printing means)

Claims (15)

Connected to printing means that can form on the recording paper a plurality of types of dots with different dot diameters according to the amount of ink, print data is output to the printing means, and dot-concentrated halftone images are printed by the printing means. In the print control device,
Ink regulation value acquisition means for acquiring an ink regulation value for regulating the total amount of ink;
A comparison means for comparing the input image signal with a threshold matrix that prestores thresholds for determining whether or not to record each pixel in a screen cell composed of a plurality of pixels of a halftone screen;
The comparison result of the comparison by the means, the type of dot diameter a respective pixel is determined to record the dots within the screen cell For each pixel that is not yet determined, are obtained by the ink regulation value acquiring means A dot type determining means for determining which of the plurality of types of dots having different dot diameters is to be formed using the ink regulation value, wherein the ink is regulated in the screen cell comprising the plurality of pixels. of the total amount so that the total amount of the ink corresponding to the ink regulation value, the Kakue element determined to print dots within the screen cell, any dots among the plurality of types of dot diameters are different dots The dot type determining means for determining whether to form;
Result of comparison by the comparing means, and output means for outputting the type of the determined dot diameter by the dot type determination means for Kakue arsenide and the pixel which is determined to record dots on the printing means as said print data A printing control apparatus comprising: The printing means is configured to be able to form at least three types of dots having different dot diameters on a recording paper,
The dot type determination means, the type of dot diameter to be formed for Kakue element that is determined to record dots of plural pixels in the screen cell, the dot diameter size order adjacent two mutually The print control apparatus according to claim 1, wherein the print control apparatus determines any of the dot diameters. Random number acquisition means for acquiring a random number for each pixel determined to record dots by the comparison means;
The dot type determination means compares the random number acquired by the random number acquisition means with a value based on the ink restriction value acquired by the ink restriction value acquisition means, and which kind of dot is formed. The printing control apparatus according to claim 1, wherein the printing control apparatus determines each pixel. A sequence storage means for storing a set of values corresponding to each pixel in the screen cell;
The dot type determination means compares the value stored in correspondence with each pixel in the number sequence storage means with the value based on the ink restriction value acquired by the ink restriction value acquisition means, and The printing control apparatus according to claim 1, wherein whether or not to form a dot is determined for each pixel.   The dot type determining means is configured so that the total amount of ink restricted in a predetermined plurality of screen cells existing in a batch becomes the total amount of ink corresponding to the ink restriction value acquired by the ink restriction value acquisition means. The print control apparatus according to claim 1, wherein a type of dot diameter is determined for each pixel of the predetermined plurality of screen cells. Print data is output to printing means that can form multiple types of dots with different dot diameters according to the amount of ink on the recording paper, and dot-concentrated halftone images are printed by the printing means, while recording within a predetermined area In a print control method that regulates the total amount of ink attached to paper,
A comparison step of comparing an input image signal with a threshold matrix that prestores thresholds for determining whether or not to record each pixel in a screen cell composed of a plurality of pixels of a halftone screen;
Said comparing step results of the comparison by, For each pixel type has not yet been determined in the dot diameter a respective pixel is determined to record the dots within the screen cell, ink regulation value for regulating the total amount of ink A dot type determining step for determining which of the plurality of types of dots having different dot diameters is to be formed, wherein the total amount of ink regulated in the screen cell comprising the plurality of pixels is the ink such that the total amount of the ink corresponding to the regulated value, determines the Kakue element determined to print dots within the screen cell, the dot diameter to form any dots of the different types of dots The dot type determining step to
The comparison result of the comparison by the process, and an output step of outputting the type of dot diameter, which is determined by the dot type determination step for Kakue and boron pixels which are determined for scoring dots on the printing means as said print data A printing control method comprising: The printing means is configured to be able to form at least three types of dots having different dot diameters on a recording paper,
The dot type determination step, the type of dot diameter to be formed for Kakue element that is determined to record dots of plural pixels in the screen cell, the dot diameter size order adjacent two mutually The printing control method according to claim 6, wherein the printing control method determines any one of the dot diameters. A random number acquisition step of acquiring a random number for each pixel determined to record dots by the comparison step;
In the dot type determination step, the random number acquired in the random number acquisition step is compared with a value based on the ink regulation value to determine which type of dot is formed for each pixel. The printing control method according to claim 6, wherein the printing control method is a printing control method.   In the dot type determining step, a value set in advance corresponding to each pixel in the screen cell is compared with a value based on the ink regulation value to determine which type of dot is formed for each pixel. The printing control method according to claim 6, wherein the printing control method is determined as follows.   In the dot type determination step, the predetermined plurality of screen cells are set such that the total amount of ink regulated in the plurality of predetermined screen cells existing in a group becomes the total amount of ink corresponding to the ink regulation value. The print control method according to claim 6, wherein the type of dot diameter is determined for each of the pixels. Connected to printing means that can form on the recording paper a plurality of types of dots with different dot diameters according to the amount of ink, print data is output to the printing means, and dot-concentrated halftone images are printed by the printing means. In a print control program executed on a computer,
An ink regulation value acquisition means for acquiring an ink regulation value for regulating the total amount of ink attached to the recording paper within a predetermined area according to the type of the recording paper;
A comparison means for comparing the input image signal with a threshold matrix that prestores thresholds for determining whether or not to record each pixel in a screen cell composed of a plurality of pixels of a halftone screen;
The comparison result of the comparison by the means, the type of dot diameter a respective pixel is determined to record the dots within the screen cell For each pixel that is not yet determined, are obtained by the ink regulation value acquiring means A dot type determining means for determining which of the plurality of types of dots having different dot diameters to form using the ink regulation value, wherein the ink is regulated in the screen cell comprising the plurality of pixels. of the total amount so that the total amount of the ink corresponding to the ink regulation value, the Kakue element determined to print dots within the screen cell, any dots among the plurality of types of dot diameters are different dots The dot type determining means for determining whether to form;
An output means for outputting to said printing means comparison result from the comparing means, the type of dot diameter, which is determined by the dot type determination means for Kakue arsenide and the pixel which is determined to record dots as the print data, A printing control program for causing a computer to function. The printing means is configured to be able to form at least three types of dots having different dot diameters on a recording paper,
The dot type determination means, the type of dot diameter to be formed for Kakue element that is determined to record dots of plural pixels in the screen cell, the two dots that are adjacent to each other in the order of magnitude of the dot diameter 12. The print control program according to claim 11, wherein the print control program is determined to be any one of the diameters. Causing the computer to function as random number acquisition means for acquiring random numbers for each pixel determined to record dots by the comparison means;
The dot type determination means compares the random number acquired by the random number acquisition means with a value based on the ink restriction value acquired by the ink restriction value acquisition means, and which kind of dot is formed. 13. The printing control program according to claim 11, wherein the printing control program is determined for each pixel. Causing the computer to function as a sequence storage means for storing a set of values corresponding to each pixel in the screen cell;
The dot type determination means compares the value stored in correspondence with each pixel in the number sequence storage means with the value based on the ink restriction value acquired by the ink restriction value acquisition means, and The printing control program according to claim 11 or 12, wherein each of the pixels determines whether to form a dot.   The dot type determining means is configured so that the total amount of ink restricted in a predetermined plurality of screen cells existing in a batch becomes the total amount of ink corresponding to the ink restriction value acquired by the ink restriction value acquisition means. The print control program according to claim 11, wherein a type of dot diameter is determined for each pixel of the predetermined plurality of screen cells.

Images