JP2010041282A - Image forming method, image forming apparatus, image formation processing program, and binarizing dither matrix pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve stability in an image formation without impairing a resolution. <P>SOLUTION: A multiple-value image is extracted in an image signal memory 11. A dot data generating portion 14 binarizes the multiple-value image extracted in the image signal memory 11 based on a binarizing pattern (binarizing dither matrix pattern) 12a. An image forming portion 15 forms an image based on this binarizing result. The binarizing pattern 12a is composed of a plurality of pixels sequentially lighted up and arranged in a form of a matrix as a patten, and the first to the n×n-th (wherein n is an optional natural number) pixels sequentially lighted up are arranged in a form of a square of n×n. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming technique, and in particular, a technique of a binarized dither matrix pattern for converting a multi-valued image (Continuous Tone Image) such as a natural image, a graphic image, or a color character into a binary image, and the binarized dither. The present invention relates to an image forming technique performed using a matrix pattern.

  When outputting a multi-value image such as a natural image, graphic image, or color character obtained from an input device such as a scanner from an output device such as a printer, the multi-value image is used as a color material. In order to express by ON / OFF (ink, toner, etc .; hereinafter, sometimes referred to as dots), it is necessary to perform binarization processing.

  A dither method is known as one of the binarization methods. In the dither method, the gradation density of a pixel is determined by comparing the value of a specific pixel (target pixel) in a multi-valued image with a preset threshold value, and a binary dither matrix pattern prepared in advance is determined. This is a method of determining dot ON / OFF for each target pixel according to the gradation density of this pixel.

With regard to such a binarized dither matrix pattern, for example, Patent Document 1 discloses that artifacts (Artifact: artificial patterns) such as moire (Moire: repeated patterns generated by mutual interference of a plurality of geometric patterns) are reduced. A binary dither matrix pattern that can be used is disclosed. This binarized dither matrix pattern has a plurality of specific points substantially symmetrical with respect to the centroid position, and preferentially lights pixels adjacent to the lit pixels in order from pixels close to these specific points. To generate continuous halftone dots and sequentially turn on almost half of the pixels constituting the binarized dither matrix pattern in the binarized dither matrix pattern. And are configured to form a checkered pattern.
JP 2005-167492 A

  In the conventional binarized dither matrix pattern, the most important point is to prevent the center of gravity of the already-arranged lighting pixels from moving as much as possible and to distort the formed image as much as possible. As described above, a plurality of pixels that are sequentially lit are arranged in a concentric shape centered on the specific point x. However, since the binarized dither matrix pattern is formed by arranging square pixels in a matrix, the peripheral length L of a halftone dot formed by adjacent lighting pixels is equal to the total area of the halftone dot. There was a tendency to become longer.

  Here, if the peripheral length L with respect to the total area of the halftone dots is long, the halftone dots after recording are easily peeled off from the recording medium such as the paper surface, and the stability of the formed image is lowered. In the past, it was difficult to remove halftone dots by increasing the total area of the halftone dots, but this was an obstacle to increasing the resolution of the formed image.

  The present invention has been made in view of the above-described problems, and a problem to be solved is to improve stability in image formation without sacrificing resolution.

  One of the image forming methods described below is a development step for developing a multi-valued image in a storage area, and binarizing the multi-valued image developed in the storage area based on a binarized dither matrix pattern. An image forming step of forming an image based on the binarization result, and the binarized dither matrix pattern is configured as a pattern in which a plurality of pixels that are sequentially lit are arranged in a matrix, In the binarized dither matrix pattern, the first to n × nth pixels (where n is an arbitrary natural number) that are sequentially lit are arranged in an n × n square shape. is there.

In this case, the perimeter of the halftone dot formed by the adjacent lighting pixel at this time is the shortest in the total area of the halftone dot.
In this binarized dither matrix pattern, the n × n + 1 th to n × (n + 1) th pixels that are sequentially lit are 4 pixels of the pixel array arranged in the n × n square shape. Among the two sides, the lighting order is arranged in a row adjacent to one of the sides closest to the first pixel, so that the first to the n × (n + 1) th are arranged. The pixels can be arranged in n × (n + 1) rectangular shapes.

In this way, the movement of the barycentric position of the lit pixels already arranged up to this point is small.
In the binarized dither matrix pattern, the pixels from the n × n + 1th to the n × (n + 1) th are the first pixels in the lighting order in one column adjacent to the side. In the case where the pixels are arranged in order from a close position and the distance from the first pixel is the same, the pixels can be arranged in an order from a position close to an intermediate position in the adjacent column.

In this way, the movement of the barycentric position of the lit pixels that have already been arranged up to this point is further reduced.
In this binarized dither matrix pattern, the n × (n + 1) + 1-th to (n + 1) × (n + 1) -th pixels that are sequentially turned on have the n × (n + 1) rectangular shape. Among the two long sides of the arranged pixel arrangement, the lighting order is arranged in one row adjacent to the long side closer to the first pixel, so that the first to the (( The pixels up to (n + 1) × (n + 1) th may be arranged in a (n + 1) × (n + 1) square shape.

In this case, the perimeter of the halftone dot formed by the adjacent lighting pixel at this time is the shortest in the total area of the halftone dot.
In this binarized dither matrix pattern, the pixels from the n × (n + 1) + 1th to the (n + 1) × (n + 1) th are in the lighting order in one column adjacent to the long side. If the distance from the first pixel is the same as the first pixel and the distance from the first pixel is the same, the pixels are arranged from the position closest to the middle position in the adjacent column. Can be.

In this way, the movement of the barycentric position of the lit pixels already arranged up to this point is small.
Another one of the image forming methods described below is a development step for developing a multi-valued image in a storage area, and the multi-valued image developed in the storage area based on a binarized dither matrix pattern. An image forming step for forming an image based on the binarization result, and the binarized dither matrix pattern is a pattern in which a plurality of pixels that are sequentially lighted one by one are arranged in a matrix. In the binarized dither matrix pattern, the first to n × n−4th pixels (where n is an arbitrary natural number greater than or equal to 4) sequentially turned on are n × n. It is arranged in a shape excluding four corners from a square shape.

  In this way, the perimeter of the halftone dots formed by the adjacent lighting pixels at this time is shortened in the total area of the halftone dots, and the feeling of roughness of the formed image is alleviated.

  In this binarized dither matrix pattern, the first to (n−1) × n−4th pixels that are sequentially lit are four corners from (n−1) × n rectangular shapes. It can be arranged in a shape excluding.

  In this way, the perimeter of the halftone dots formed by the adjacent lighting pixels at this time is shortened in the total area of the halftone dots, and the feeling of roughness of the formed image is alleviated.

  Further, in this binarized dither matrix pattern, the first to mth pixels (m is a natural number of 2 or more) that are sequentially lit are collectively turned on in the first lighting order as a pixel block. be able to.

In this case, since the ink adhesion area is increased, the stability of the formed image is improved.
The image forming method described above further includes a gradation characteristic changing step for changing the gradation characteristic of the multi-valued image developed in the storage area to a predetermined characteristic prepared in advance. The step can binarize the multi-valued image after changing the gradation characteristics in the gradation characteristic changing step, and form an image based on the binarization result.

By doing in this way, adjustment of a tone curve etc. can be performed easily and a moire and an artifact can be reduced.
Further, another one of the image forming methods described below includes a development step for developing a multi-valued image in a storage area, and a multi-valued image developed in the storage area as a binarized dither matrix pattern. An image forming step of forming an image based on the binarization result, and the binarized dither matrix pattern is a pattern in which a plurality of pixels are arranged in a matrix. Are formed as a lit pixel area pattern for managing the pixels in the turn-on order and a non-lit pixel area pattern for managing a plurality of the pixels in the turn-off order, and the image forming step includes the lit pixel area pattern and the unlit pixel area pattern. A checkered pattern or a pattern similar to a checkered pattern is arranged in a pattern similar to the checkered pattern, and a pair of the lit pixel region pattern and the unlit image adjacent to each other in the checkered pattern arrangement By the region pattern to form the image by gray scales corresponding to the pixel value of each pixel constituting the multi-value image, is that.

If the dot turn-off order is managed in this way, the occurrence of artifacts is suppressed.
The image forming apparatus described below implements the above-described image forming method. Further, the image forming processing program to be described below is executed by the arithmetic processing unit to implement the above-described image forming method. According to these, the same operations and effects as the image forming method described above are obtained.

  According to the method and apparatus having the above requirements, there is an effect that stability in image formation can be improved without sacrificing resolution.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram schematically illustrating a functional configuration of a printing system, which is an image forming apparatus that implements the present invention. FIG. 2 is a diagram schematically illustrating a hardware configuration of the printing system.

  As shown in FIG. 2, the printing system 1 includes a personal computer (PC) 2 and a printing apparatus 3, and a multivalued image created or acquired by the PC 2 is converted into a binarized dither matrix pattern. Is used to control ON / OFF of each dot, and an image is formed (printed) based on the binarization result. Further, the printing system 1 represents a multi-valued image by the size of minute dots (halftone dots) of a color material that adheres to the surface of a recording medium such as paper, film, and printing plate. The density of the image is expressed by the area ratio of dots per area.

  The printing apparatus 3 forms an image by forming (dotting) a color material (toner, ink, etc.) on a recording medium such as a printing paper of a printing apparatus such as a laser beam printer, an LED printer, or an offset printing machine. The gradation of the multi-value image (continuous tone image) is reproduced by the area of the color material (dot) formed on the recording medium.

  The printing apparatus 3 includes a CPU (Central Processing Unit) 31, a ROM (Read Only Memory) 32, a RAM (Random Access Memory) 33, and an image forming unit 34. The ROM 32 stores an application program for realizing a color calculation unit 10, a gradation characteristic changing unit 13, and a dot data generating unit 14, which will be described later, and the CPU 31 executes the application program from the ROM 32. The functions (details will be described later) as the color calculation unit 10, the gradation characteristic changing unit 13, and the dot data generating unit 14 of FIG. 1 are realized, and the image forming method according to the present invention is performed.

  In the present embodiment, the computer is a concept including hardware and an operation system, and means hardware that operates under the control of the operation system. Further, when the operation system is unnecessary and the hardware is operated by the application program alone, the hardware itself corresponds to the computer. The hardware includes at least a microprocessor such as a CPU (Central Processing Unit) and means for reading a computer program recorded on a recording medium. In the present embodiment, the PC 2 and the printing apparatus 3 each have a function as a computer.

  Application programs for realizing the functions as the color calculation unit 10, the gradation characteristic changing unit 13, and the dot data generating unit 14 are, for example, a flexible disk, a CD-ROM, a CD-R, a CD-R / W, a DVD. , DVD-R, DVD-R / W, magnetic disk, optical disk, magneto-optical disk, and the like recorded in a computer-readable recording medium. Then, the computer reads the application program from the recording medium, transfers it to the internal storage device or the external storage device, stores it, and uses it. Such a program may be recorded in a storage device (recording medium) such as a magnetic disk, an optical disk, or a magneto-optical disk, and provided from the storage device to a computer via a communication path. Here, when realizing the functions as the color calculation unit 10, the gradation characteristic changing unit 13, and the dot data generation unit 14, the functions are stored in an internal storage device (in this embodiment, the ROM 32 and the RAM 33 of the printing device 3). The application program is executed by the microprocessor of the computer (CPU 31 of the printing apparatus 3 in this embodiment). At this time, the computer may read and execute the program recorded on the recording medium.

  In addition to the recording media described above, the recording medium in the present embodiment includes IC cards, ROM cartridges, magnetic tapes, punch cards, computer internal storage devices (memory such as RAM and ROM), external storage devices, etc. Various computer-readable media such as printed matter on which codes such as codes are printed can also be used.

  The printing system 1 generates dots on the surface of a recording medium such as paper, film, and printing plate based on an image signal of a multi-value image. As shown in FIG. , An image signal memory (storage area) 11, a pattern memory 12, a gradation characteristic changing unit 13, a dot data generating unit 14, and an image forming unit 15.

  The color calculation unit 10 performs color calculation related to an image signal of a multi-value image, and performs color correction, gradation on an input image signal (for example, represented by a pixel value of 0 to 255). Various processes such as tone correction, black plate formation, undercolor removal, and sharpness enhancement are performed.

  The image signal memory 11 stores the image signal processed by the color calculation unit 10 and functions as a storage area for developing a multi-valued image. The RAM 33 of the printing apparatus 3 is used.

  The pattern memory 12 stores a binary dither matrix pattern (hereinafter also referred to as a binarization pattern) 12a in which a plurality of pixels that are sequentially lit are arranged in a matrix, as will be described later. Actually, an application program is stored in the RAM 33, ROM 32, or other storage medium (for example, a storage device of the PC 2), and the pattern memory 12 is realized by the CPU 31 of the printing device 3 executing the application program. Thus, it can be considered that the binarization pattern 12 a is stored in the pattern memory 12.

  The gradation characteristic changing unit 13 corrects the gradation characteristic of the multilevel image developed in the storage area of the image signal memory 11 based on a lookup table prepared in advance. FIG. 3 shows an example of a correction curve showing the relationship between the input and output shown in this lookup table.

In FIG. 3, the “input” on the horizontal axis represents the pixel value of each pixel in the image signal, and the “output” on the vertical axis represents the pixel value after correction.
Assuming that the range of possible pixel values is 0 to 255, the pixel value “0” corresponds to “0%” and the pixel value “255” corresponds to “100%”. That is, in the characteristic example shown in FIG. 3, when the pixel value of each pixel in the image signal is “0” (input “0%”), the corrected pixel value is also “0” (output “0”). % ”), And the pixel value of each pixel in the image signal is“ 255 ”(input“ 100% ”), the corrected pixel value is also“ 255 ”(output“ 100% ”). On the other hand, when the pixel value of each pixel in the image signal is “127” (that is, when the input is “50%”), the output is “102” (output “40%”).

  The gradation characteristic changing unit 13 converts the pixel value of the image signal based on this lookup table, and passes the converted value to the dot data generating unit 14. Here, the gradation characteristics of the multi-valued image can be arbitrarily changed by changing the correspondence relationship of the lookup table. That is, by changing the lookup table, for example, the tone curve can be easily adjusted, and moire and artifacts can be reduced.

In the present embodiment, the pixel value of the image signal is converted by the gradation characteristic changing unit 13, but for example, the pixel value may not be converted by the gradation characteristic changing unit 13.
The dot data generation unit (binarization processing unit) 14 binarizes the image signal input from the gradation characteristic changing unit 13 using the binarization pattern 12a recorded in the pattern memory 12, Data (dot data) for fixing dots on the recording medium by the image forming unit 15 is generated.

  Specifically, the dot data generation unit 14 compares the value converted by the gradation characteristic changing unit 13 with a preset threshold value and obtains the number of pixels to be lit in the binarization pattern 12a. In accordance with the lighting order set in the binarization pattern 12a, dot data that is lit until it matches the obtained number of pixels is generated. That is, according to the lighting order set in the binarization pattern 12a, the dot data generation unit 14 selects from the start pixel of the lighting order to the pixel in which the lighting order that matches the obtained number of pixels is set according to the lighting order. By doing (lighting up), the pixels forming the color material are determined, and dot data is generated based on this information.

  The image forming unit 15 corresponds to the image forming unit 34 in FIG. 2, and performs image formation by fixing dots on a recording medium in accordance with the dot data generated by the dot data generating unit 14. That is, the multi-valued image developed in the image signal memory 11 is binarized by the dot data generation unit 14, and the image forming unit 15 forms an image based on the binarization result. For example, in the printing apparatus 3 that employs the electrostatic printing method, an exposure apparatus or the like functions as the image forming unit 15. In this case, the dot data generation unit 14 generates exposure data as dot data.

Next, FIG. 4 will be described. FIG. 4 is a flowchart showing the contents of the control process executed by the CPU 31 of the printing apparatus 3.
The CPU 31 can perform this control process by reading the above-described application program from the ROM 32 or the RAM 33) of the printing apparatus 3 and executing it. The CPU 31 starts this control process upon receiving a predetermined print start instruction from the PC 2.

  When starting this control process, the CPU 31 first performs a process of storing a binarization pattern 12a described later in a predetermined storage area in the RAM 33 in S101. With this process, the RAM 33 can function as the pattern memory 12.

Next, in S102, the CPU 31 performs a process of capturing an image signal of a multi-value image sent from the PC 2.
Next, the CPU 31 executes color calculation processing in S103, and performs various processing such as color correction, gradation correction, black plate formation, undercolor removal, sharpness enhancement, and the like on the image signal captured by the processing in S102. Apply. The CPU 31 functions as the color calculation unit 10 by executing the process of S103.

  Next, the CPU 31 executes image signal expansion processing in S104, and expands the image signal (multi-valued image) after the color calculation processing in S103 to a predetermined storage area of the RAM 33 functioning as the image signal memory 11. I do.

  Next, in S105, the CPU 31 performs gradation characteristic change processing (change processing of each pixel value indicated by the image signal) on the image signal developed in the image signal memory 11 by the image signal development processing in S104. ) As necessary. The CPU 31 functions as the gradation characteristic changing unit 13 by executing the process of S105.

  Next, the CPU 31 executes an image signal binarization process in S106, and binarizes the image signal on the image signal memory 11 using the binarization pattern 12a stored in the pattern memory 12. Generate dot data. The CPU 31 functions as the dot data generation unit 14 by executing the process of S106.

Next, in S107, the CPU 31 executes image forming processing to control the image forming unit 15, and fixes the ink on the recording medium according to the dot data generated by the image signal binarization processing in S106. Let the formation take place.

  Next, in S108, the CPU 31 performs a process of determining whether or not the next image signal subsequent to the image formed is sent from the PC 2. Here, when it is determined that the next image signal has been sent (when the determination result is Yes), the processing returns to S102 and the above-described processing is repeated. On the other hand, when it is determined that the next image signal has not been sent (when the determination result is No), the control process of FIG. 4 ends.

When the CPU 31 performs the above control processing, the printing apparatus 3 forms an image based on the image signal sent from the PC 2.
Next, the binarization pattern 12a used for the dot data generation unit 14 to binarize the image signal on the image signal memory 11 will be described.

  In the following description, fixing a dot (color material) is expressed as “lighting a black dot”, and not fixing a dot (color material) is “turning off a black dot” or “ It will be expressed as “lighting white dots”. Therefore, the actual color of the dots (coloring material) is not limited to black, and the color of the recording medium on which the dots are fixed is not limited to white.

  Next, FIG. 5 will be described. FIG. 5 shows an example of the dot data generation result by the dot data generation unit 14, and the pixel value after correction by the gradation characteristic changing unit 13 is just in the middle of the possible range of the pixel value. The generation result is shown in the case (for example, if the possible range of the pixel value is 0 to 255, the value “just in the middle” of the pixel value is “128”).

  In this case, in the recording medium, the dot data is generated so that the area where the black dots are turned on and the area where the white dots are turned on (that is, the black dots are turned off) are equal to each other. "Is expressed as a gradation. In addition, as shown in FIG. 5, the dot data generation pattern at this time includes a pixel area in which black dots are sequentially turned on (black dot lighting pixel area B) and a pixel area in which black dots are sequentially turned off (black dot off pixel area). W, that is, a pixel area in which white dots are sequentially turned on), a checkered pattern is formed, and a pixel area in which black dots are turned on and a black dot are turned off (white dots are turned on) The occurrence of artifacts is suppressed by eliminating the bias in the arrangement with the pixel area.

  In the example of FIG. 5, a complete checkered pattern is formed by the black dot lighting pixel region B and the black dot extinguished pixel region W. However, the checkered pattern may be formed even if the checkered pattern is not perfect. A pattern similar to may be used. Here, the “pattern similar to the checkerboard pattern” means that, from the checkerboard pattern, p pixels of lit pixels are changed to unlit pixels, and the same number of pixels (that is, p pixels) are turned off. In the present application, a pattern having a p value of 8 or less is particularly referred to as a “pattern similar to a checkered pattern”. In addition, when the value of p is 8, a pattern in which two pixels, that is, a light-on pixel and a light-off pixel in the vicinity of the four corners in a perfect square checkered pattern are replaced.

Here, in the present embodiment, when the pixel value after the correction by the gradation characteristic changing unit 13 is equal to or less than the above-described “just intermediate” value, within the black dot lighting pixel region B in FIG. According to the lighting order set in the value pattern 12a, the black dots are sequentially lighted until the number of pixels obtained as described above matches. On the other hand, when the pixel value after the correction by the gradation characteristic changing unit 13 is larger than the above-described “just intermediate” value, the pixel value 2 in the black dot unlit pixel region W adjacent to the black dot lit pixel region B is 2 In accordance with the turn-off sequence set in the value pattern 12a, the black dots are sequentially turned off until the number of pixels obtained as described above is matched (more precisely, the black dots are turned on and the area W is black. From the state of being filled with dots, the black dots are sequentially turned off until they match the number of pixels obtained as described above.

  As described above, in this embodiment, the lit pixel region for managing the lighting order of the dots and the unlit pixel region for managing the turn-off order of the dots are arranged in a checkered pattern or a pattern similar to the checkered pattern, and a pair of adjacent pairs An image is formed by expressing gradation corresponding to the pixel value of each pixel constituting the multi-valued image by the lit pixel region and the unlit pixel region. In this way, when managing not only the dot turn-on order but also the dot turn-off order, in particular, the pixel value of each pixel constituting the multi-valued image is more than the “just middle” value. When it is large, the generation of artifacts is suppressed.

Hereinafter, the binary dither matrix pattern in the lit pixel region and the unlit pixel region will be described with some examples.
First, FIG. 6 will be described. FIG. 6 shows a first example of a binarized dither matrix pattern.

In FIG. 6, (a) shows the lighting order of white dots (order of extinction from black dots that are all lit), and (b) shows the lighting order of black dots. It is.
In the binarized dither matrix pattern illustrated in FIG. 6 and subsequent figures, the positions of the squares indicate the positions of the dots, and the numbers assigned to the squares indicate the dots at the positions. The lighting order of is shown. In each figure, the lighting order of the white dots is ascending order of the assigned numbers, and the lighting order of the black dots is the descending order of the attached numbers.

In the first example shown in FIG. 6, the first to n × n-th pixels (where n is an arbitrary natural number) that are sequentially lit are arranged in an n × n square shape. An example is shown.
In FIG. 6A, for example, when attention is paid to each pixel in the lighting order from the first to the ninth (that is, n = 3) that is sequentially lit, these pixels are 3 × 3 squares. Are arranged in a shape. Further, for example, when attention is paid to each pixel in the lighting order from the first to the 16th (that is, n = 4), which are sequentially lit, these pixels are arranged in a 4 × 4 square shape. .

  The same applies to (b) of FIG. 6. For example, each pixel in the lighting order from the first to the ninth (that is, n = 3) sequentially turned on, that is, (b) of FIG. 6. When attention is paid to each pixel to which any number from “99” to “91” is attached, these pixels are arranged in a 3 × 3 square shape. Further, for example, each pixel in the lighting order from the first to the 16th (that is, n = 4) that is sequentially lit, that is, any one of “99” to “84” in FIG. 6B. When attention is paid to each pixel numbered, these pixels are arranged in a 4 × 4 square shape.

  As described above, the first example shown in FIG. 6 is such that the first to n × n-th pixels that are sequentially turned on are arranged in an n × n square shape. When the dot data generation unit 14 performs binarization based on such a binarization pattern 12a, the shape of each pixel is a square. The perimeter is the shortest in the total area of the halftone dots. Therefore, the stability of the formed image is improved as compared with the conventional technique that employs the pattern as shown in FIG. In other words, the stability of the formed image is improved without taking measures to increase the total area of the halftone dots, so that the resolution of the formed image does not need to be reduced.

  By the way, in the first example shown in FIG. 6, the n × n + 1 th to n × (n + 1) th pixels that are sequentially turned on are arranged in an n × n square array. Among the four sides, the lighting order is arranged in a row adjacent to any one of the sides closest to the first pixel, so that the first to the n × (n + 1) th are arranged. Pixels are arranged in an n × (n + 1) rectangular shape.

  In FIG. 6A, for example, attention is paid to the tenth to twelfth pixels (that is, n = 3) that are sequentially turned on. These pixels are out of four sides of a pixel array arranged in a 3 × 3 square shape (that is, a pixel array composed of pixels in the lighting order from the first to the ninth). Any side that is closest to the first pixel in lighting order (in the figure, the distance from the pixel numbered “1” to the four sides is the same, so it was arbitrarily selected. , Arranged from the left side by side in one column adjacent to the sides of the pixel columns numbered “4”, “2”, and “8”. With this arrangement, the pixels in the lighting order from the first to the twelfth are arranged in a rectangular shape of 3 × 4.

  In FIG. 6A, attention is paid to, for example, the 17th to 20th pixels (that is, n = 4) that are sequentially turned on. These pixels are composed of four sides of a pixel array arranged in a 4 × 4 square shape (that is, a pixel array composed of pixels in the lighting order from the first to the 16th). Any of the sides that are closest to the first pixel in the lighting order (in the figure, there are two sides that are close to the pixel numbered “1”. From the left, the pixels are arranged in a row adjacent to the sides of the pixel columns numbered “15”, “6”, “5”, and “9”. And by this arrangement | sequence, the pixel from the 1st to 20th lighting order is arranged in the rectangular shape of 4x5.

  The same applies to FIG. 6B. For example, attention is paid to the 17th to 20th pixels that are sequentially lit (that is, n = 4), that is, each pixel that is given any number from “83” to “80”. These pixels are arranged in a 4 × 4 square array (that is, any number from “99” to “84” in the lighting order from the first to the 16th). Among the four sides of the attached pixel array, one of the sides closest to the first pixel in the lighting order (in the figure, the lighting order is the first “99” Since there are two sides close to the pixel numbered “”, numbers “91”, “95”, “94”, and “85” from the top, arbitrarily selected from these two sides, are numbered. Are arranged in a row adjacent to the side of the pixel row). And by this arrangement | sequence, the pixel from the 1st to 20th lighting order is arranged in the rectangular shape of 4x5.

  As described above, the first example shown in FIG. 6 includes n × (n + 1) pixels from the first to n × (n + 1) th (where n is an arbitrary natural number) that are sequentially turned on. They are arranged in a rectangular shape. When the dot data generation unit 14 performs binarization based on such a binarization pattern 12a, the shape of each pixel is a square. The perimeter is also the shortest in the total area of the halftone dots. Therefore, the stability of the formed image is improved as compared with the conventional technique that employs the pattern as shown in FIG. In other words, the stability of the formed image is improved without taking measures to increase the total area of the halftone dots, so that the resolution of the formed image does not need to be reduced.

Here, the n × n + 1 th to n × (n + 1) th pixels that are sequentially lit are arranged in the lighting order among the four sides of the pixel array in which n × n squares are arranged. Are arranged in a row adjacent to one of the sides closest to the first pixel. This is so that the center of gravity position of the already lit pixels does not move as much as possible.

  Furthermore, in the first example shown in FIG. 6, the pixels from the (n × n + 1) th to the n × (n + 1) th sequentially lit are arranged in the above-mentioned n × n square shapes. In one column adjacent to one side of the pixel array, the lighting order is arranged in order from the position close to the first pixel. Further, when the distance from the first pixel is the same, the pixels are arranged in order from a position close to an intermediate position in the adjacent column.

  In FIG. 6A, for example, attention is paid to the tenth to twelfth pixels (that is, n = 3) that are sequentially turned on. These pixels are composed of 4 sides of a pixel array arranged in a 3 × 3 square shape (that is, a pixel array composed of pixels in the lighting order from the first to the ninth), Any side whose lighting order is closest to the first pixel (in the figure, pixels having the numbers “4”, “2”, and “8” selected from the left selected as described above) Are arranged in a row adjacent to the side of the row). Here, the pixel “10” is arranged closer to the pixel “1” than the pixels “11” and “12”. Note that the pixels “11” and “12” have the same distance from the pixel “1”, and the distance from a position close to the middle position of the side is also the same. The position of is arbitrarily selected.

  In FIG. 6A, attention is paid to, for example, the 17th to 20th pixels (that is, n = 4) that are sequentially turned on. These pixels are composed of four sides of a pixel array arranged in a 4 × 4 square shape (that is, a pixel array composed of pixels in the lighting order from the first to the 16th). , Any side whose lighting order is closest to the first pixel (in the figure, the numbers “15”, “6”, “5”, “9” selected from the left are selected as described above) Are arranged in a row adjacent to the side of the attached pixel column). Here, the pixel “17” is arranged at a position closer to the pixel “1” than the pixels “18”, “19”, and “20”. Next, the pixel “18” is the same as the pixel “19” from the pixel “1”, but the pixel from the position near the middle position of the side is “19”. Is also located in a close position. Next, the pixel “17” is arranged closer to the pixel “1” than the pixel “20”. The last “20” pixel, which is the lighting order, is arranged at the remaining position in one column adjacent to the above-described side.

  The same applies to FIG. 6B. For example, attention is paid to the 17th to 20th pixels that are sequentially lit (that is, n = 4), that is, each pixel that is given any number from “83” to “80”. These pixels are arranged in a 4 × 4 square array (that is, any number from “99” to “84” in the lighting order from the first to the 16th). Among the four sides of the attached pixel array, the one that is closest to the first pixel in the lighting order (in the figure, selected as described above, the upper side To “91”, “95”, “94”, and “85” (sides of pixel columns numbered) are arranged in a line adjacent to each other. Here, the pixel “83” is arranged at a position closer to the pixel “99” than the pixels “82”, “81”, and “80”. Next, the pixel “82” is the same as the pixel “81” from the pixel “99”, but the pixel from the position near the middle position of the side is “81”. Is also located in a close position. Next, the pixel “81” is arranged at a position closer to the pixel “99” than the pixel “80”. And the pixel of “80”, which is the last lighting order, is arranged at the remaining position in one column adjacent to the above side.

  As described above, in the first example shown in FIG. 6, the n × n + 1 th to n × (n + 1) th pixels that are sequentially turned on are arranged in the aforementioned n × n squares. In one column adjacent to one side of the pixel arrangement, the lighting order is arranged in order from the position close to the first pixel. Further, when the distance from the first pixel is the same, the pixels are arranged in order from a position close to an intermediate position in the adjacent column. This arrangement order is also considered so that the position of the center of gravity of the already lit pixels does not move as much as possible.

  Further, in the first example shown in FIG. 6, the n × (n + 1) + 1-th to (n + 1) × (n + 1) -th pixels that are sequentially turned on are the n × (n + 1) pixels described above. Of the two long sides of the pixel array arranged in a rectangular shape, the lighting order is arranged in a row adjacent to the long side closer to the first pixel, thereby sequentially lighting up. The first to (n + 1) × (n + 1) th pixels are arranged in a (n + 1) × (n + 1) square shape.

  In FIG. 6A, attention is paid to, for example, the thirteenth to sixteenth pixels (that is, n = 3) that are sequentially turned on. These pixels are composed of two long sides of a pixel array arranged in a 3 × 4 rectangular shape (that is, a pixel array composed of pixels in the first to twelfth lighting order). Thus, the longer side closer to the first pixel in the lighting order (in the figure, since the distance from the pixel numbered “1” of the two long sides is the same, the two long sides Arranged in a row adjacent to the side of the pixel row arbitrarily selected from the sides and numbered “6”, “3”, “4”, “11” from the top) . And by this arrangement | sequence, the pixel from the 1st to 16th lighting order is arranged in the shape of 4x4 square.

  In FIG. 6A, attention is focused on, for example, the 21st to 25th pixels (that is, n = 4) that are sequentially lit. These pixels are composed of two long sides of a pixel array arranged in a 4 × 5 rectangular shape (that is, a pixel array composed of pixels in the lighting order from the first to the twentieth). Thus, the longer side whose lighting order is closer to the first pixel (in the figure, the pixels numbered “19”, “9”, “7”, “8”, “12” from the top) Are arranged in a row adjacent to the side of the row). With this arrangement, the pixels in the lighting order from the first to the 25th are arranged in a 5 × 5 square shape.

  The same applies to FIG. 6B. For example, attention is focused on the 21st to 25th pixels (that is, n = 4) that are sequentially lit, that is, each pixel that is given any number from “79” to “75”. These pixels are arranged in a 4 × 5 rectangular shape (that is, any number from “99” to “80”, which is the lighting order from the first to the twentieth). Among the two long sides of the pixel arrangement formed by each pixel, the long side whose lighting order is closer to the first pixel (in the figure, the lighting order is the first "99" ”From the left, which is the long side close to the pixel numbered“ ”, and the side of the pixel row numbered“ 81 ”,“ 91 ”,“ 93 ”,“ 92 ”,“ 88 ”) They are arranged in one adjacent row. With this arrangement, the pixels in the lighting order from the first to the 25th are arranged in a 5 × 5 square shape.

  Thus, in the first example shown in FIG. 6, the first to (n + 1) × (n + 1) th pixels that are sequentially lit are arranged in a (n + 1) × (n + 1) square shape. It has been done. Accordingly, the perimeter of the halftone dots formed by the adjacent lighting pixels at this time is the shortest in the total area of the halftone dots, so that the stability of the formed image is improved.

Furthermore, in the first example shown in FIG. 6, the pixels from the (n × (n + 1) +1) th to (n + 1) × (n + 1) th sequentially turned on are the long sides (n × (( n + 1) Among the two long sides of the pixel array arranged in a rectangular shape, the lighting order is the first among the columns adjacent to the longest side whose lighting order is closer to the first pixel) Are arranged in order from the position close to the pixel. Further, when the distance from the first pixel is the same, the pixels are arranged in order from a position close to an intermediate position in the adjacent column.

  In FIG. 6A, attention is paid to, for example, the thirteenth to sixteenth pixels (that is, n = 3) that are sequentially turned on. These pixels are composed of two long sides of a pixel array arranged in a 3 × 4 rectangular shape (that is, a pixel array composed of pixels in the first to twelfth lighting order). Thus, the longer side whose lighting order is closer to the first pixel (in the figure, the numbers “6”, “3”, “4”, “11” selected from the top are selected as described above. Are arranged in a row adjacent to the side of the attached pixel column). Here, the pixel “13” is arranged at a position closer to the pixel “1” than the pixels “14”, “15”, and “16”. Next, the pixel “14” is the same as the pixel “15” from the pixel “1”, but the pixel from the position near the middle position of the side is “15”. Is also located in a close position. Next, the “15” pixel is arranged closer to the “1” pixel than the “16” pixel. And the pixel of “16” which is the last lighting order is arranged at the remaining position in one column adjacent to the above side.

  In FIG. 6A, attention is focused on, for example, the 21st to 25th pixels (that is, n = 4) that are sequentially lit. These pixels are composed of two long sides of a pixel array arranged in a 4 × 5 rectangular shape (that is, a pixel array composed of pixels in the lighting order from the first to the twentieth). Then, the long side whose lighting order is closer to the first pixel (in the figure, “19”, “9”, “7”, “8”, “12” selected from the top is selected as described above. Are arranged in one column adjacent to the side of the pixel column to which " Here, the pixel “21” is arranged at a position closer to the pixel “1” than the pixels “22”, “23”, “24”, and “25”. Next, the pixels “22” and “23” are arranged closer to the pixel “1” than the pixels “24” and “25”. Note that the pixel “22” and the pixel “23” have the same distance from the pixel “1”, and the distance from a position close to the middle position of the side is also the same. The positions of these pixels are arbitrarily selected. Also, since the “24” pixel and the “25” pixel have the same distance from the “1” pixel, and the distance from the position close to the middle position of the above-mentioned side is also the same. The positions of these pixels are arbitrarily selected.

  The same applies to FIG. 6B. For example, attention is focused on the 21st to 25th pixels (that is, n = 4) that are sequentially lit, that is, each pixel that is given any number from “79” to “75”. These pixels are arranged in a 4 × 5 rectangular shape (that is, any number from “99” to “80”, which is the lighting order from the first to the twentieth). Among the two long sides of the pixel arrangement formed by each pixel, the long side whose lighting order is closer to the first pixel (in the figure, the left side selected as described above) To “81”, “91”, “93”, “92”, and “88” are arranged in a line adjacent to each other). Here, the pixel “79” is arranged at a position closer to the pixel “99” than the pixels “78”, “77”, “76”, and “75”. Next, the “78” and “77” pixels are arranged closer to the “99” pixel than the “76” and “75” pixels. Note that the “78” pixel and the “77” pixel have the same distance from the “99” pixel, and the distance from the position close to the middle position of the side is also the same. The positions of these pixels are arbitrarily selected. Also, since the “76” pixel and the “75” pixel have the same distance from the “99” pixel, and the distance from a position close to the middle position of the side is also the same. The positions of these pixels are arbitrarily selected.

Thus, in the first example shown in FIG. 6, the pixels from the (n × (n + 1) +1) th to the (n + 1) × (n + 1) th sequentially turned on are the long sides (n) described above. Among the two long sides of the pixel array arranged in × (n + 1) rectangular shapes, the lighting order is the first in the row adjacent to the lighting order that is the longer side closer to the first pixel). They are arranged in order from the position close to the first pixel. Further, when the distance from the first pixel is the same, the pixels are arranged in order from a position close to an intermediate position in the adjacent column. This arrangement order is designed so that the position of the center of gravity of the already lit pixels does not move as much as possible.

Next, FIG. 7 will be described. FIG. 7 shows a second example of the binarized dither matrix pattern.
In FIG. 7, (a) shows the lighting order of white dots (order of extinction from black dots that are all lit), and (b) shows the lighting order of black dots. is there.

  In the second example shown in FIG. 7, pixels from the first to n × n−4th (in the second example, n is an arbitrary natural number greater than or equal to 4) that are sequentially turned on, An example is shown in which n × n square shapes are arranged in a shape excluding four corners.

  In FIG. 7A, attention is paid to each pixel in the lighting order from the first to the 21st (that is, n = 5) that is sequentially turned on. Then, these pixels are obtained by removing four corners (that is, grid positions to which numbers “22”, “23”, “28”, and “33” are attached) from 5 × 5 square shapes. Arranged in a shape. Also, for example, attention is paid to each pixel in the lighting order from the first to the 32nd (that is, n = 6) that is sequentially turned on. Then, these pixels have 6 × 6 square shapes and 4 corners (that is, grid positions with numbers “33”, “34”, “40”, and numbers). It is arranged in a shape excluding the lower right corner (the grid position).

  The same applies to FIG. 7B. For example, the first to 21st (that is, n = 5) pixels that are sequentially lit, that is, any number from “99” to “79” in FIG. 7B. Pay attention to each pixel marked with. Then, these pixels are excluded from the 5 × 5 square shape except for the four corners (that is, each square position numbered “78”, “77”, “72”, “66”). Are arranged in different shapes. Further, for example, each pixel in the lighting order from the first to the 32nd (that is, n = 6) that is sequentially lit, that is, any one of “99” to “68” in FIG. 7B. Pay attention to each pixel numbered with. Then, these pixels are assigned the square positions of 6 × 6 squares, that is, the grid positions to which the numbers “67”, “66”, and “61” are assigned, and the numbers. It is arranged in a shape excluding the upper right corner (not shown).

  As described above, in the second example shown in FIG. 7, the first to n × n−4th pixels (where n is an arbitrary natural number of 4 or more) that are sequentially turned on are n × n. It is arranged in a shape excluding four corners from a square shape. When the dot data generation unit 14 performs binarization based on such a binarization pattern 12a, the shape of each pixel is a square. The perimeter can be shortened in the total area of the halftone dots. Therefore, the stability of the formed image is improved as compared with the conventional technique that employs the pattern as shown in FIG. In other words, the stability of the formed image is improved without taking measures to increase the total area of the halftone dots, so that the resolution of the formed image does not need to be reduced. Further, in the second example, unlike the first example, the arrangement of the first to n × n-th pixels that are sequentially lit does not form n × n square shapes. By doing so, there is a feeling of roughness that may appear in a formed image obtained when the image signal is binarized using the binarized dither matrix pattern according to the first example illustrated in FIG. Alleviated.

By the way, in the second example shown in FIG. 7, the first to (n−1) × n−4th pixels that are sequentially turned on are from (n−1) × n rectangular shapes. They are arranged in a shape excluding the four corners.

  In FIG. 7A, attention is paid to the pixels in the lighting order from the first to the 26th (that is, n = 6), which are sequentially turned on. Then, these pixels excluding 4 corners (that is, each grid position numbered “27”, “28”, “33”, “40”) from 5 × 6 rectangular shapes. Are arranged in different shapes. Also, for example, attention is paid to each pixel in the lighting order from the first to the 38th (that is, n = 7) that is sequentially turned on. Then, these pixels are divided into four corners from 6 × 7 rectangular shapes (that is, each grid position numbered with “39” and “40”, and the upper right corner with no number). And the grid positions in the lower right corner).

  The same applies to FIG. 7B. For example, each pixel in the lighting order from the first to the 26th (that is, n = 6) that is sequentially lit, that is, any number from “99” to “74” in FIG. Pay attention to each pixel marked with. Then, these pixels are excluded from the 5 × 6 rectangular shape except for the four corners (that is, each grid position numbered with “73”, “72”, “66”, “61”). Are arranged in different shapes. Also, for example, each pixel in the lighting order from the first to the 38th (that is, n = 7) that is sequentially lit, that is, any one of “99” to “62” in FIG. Pay attention to each pixel numbered with. Then, these pixels are divided into four corners from 6 × 7 rectangular shapes (that is, each grid position numbered with “61” and “60”, and the upper left corner with no number). And the grid position in the upper right corner).

  Thus, in the second example shown in FIG. 7, the first to (n−1) × n−4th pixels that are sequentially lit are (n−1) × n rectangles. It is arranged in a shape excluding the four corners from the shape. When the dot data generation unit 14 performs binarization based on such a binarization pattern 12a, the shape of each pixel is a square. The perimeter can be shortened in the total area of the halftone dots. Therefore, the stability of the formed image is improved. In other words, the stability of the formed image is improved without taking measures to increase the total area of the halftone dots, so that the resolution of the formed image does not need to be reduced. Further, in the second example, unlike the first example, the arrangement of the first to (n−1) × n-th pixels that are sequentially lit is (n−1) × n. The rectangular shape is not formed. By doing so, there is a feeling of roughness that may appear in a formed image obtained when the image signal is binarized using the binarized dither matrix pattern according to the first example illustrated in FIG. Alleviated.

  In addition, in the arrangement of the pixels that are the binarized dither matrix pattern, the effect of alleviating the rough feeling that may appear in the formed image by arranging the pixels in the shape excluding the four corners from the rectangular shape is the above-described n It is not obtained only from the shape obtained by removing the four corners from the square shape of each piece × n and the shape obtained by removing the four corners from the (n−1) × n rectangular shape, A shape obtained by removing four corners from a rectangular shape (where m is an arbitrary natural number) has a similar effect in comparison with the case of m × n rectangular shapes that do not exclude the four corners. Next, FIGS. 8, 9, and 10 will be described. 8, 9, and 10 show a third example, a fourth example, and a fifth example of the binarized dither matrix pattern, respectively.

  8, 9, and 10, (a) shows the turn-on order of white dots (turn-off order from all black dots turned on), and (b) shows the black dots. This shows the lighting order of the dots.

The third example of the binarized dither matrix pattern shown in FIG. 8 is the first example with the first to second pixels that are sequentially turned on as the pixel block in the second example shown in FIG. Accordingly, the lighting order of each pixel after that is raised one by one.

  The fourth example of the binarized dither matrix pattern shown in FIG. 9 is the same as the second example shown in FIG. 7 except that the first to third pixels that are sequentially lit are used as pixel blocks. The lights are collectively turned on in the first lighting order, and accordingly, the lighting order of each subsequent pixel is raised one by one.

  Furthermore, the fifth example of the binarized dither matrix pattern shown in FIG. 10 is the same as the second example shown in FIG. 7 except that the first to fourth pixels that are sequentially lit are used as pixel blocks. The lights are collectively turned on in the first lighting order, and accordingly, the lighting order of each subsequent pixel is raised one by one.

  As described above, in the second example of the binarized dither matrix pattern shown in FIG. 7, the first to mth pixels (m is a natural number of 2 or more) that are sequentially lit are used as the pixel block. You may make it light up collectively in order of the 2nd lighting. By doing in this way, since the ink adhesion area becomes wider than when only the first pixel in the lighting order is isolated and arranged, the stability of the formed image can be improved.

As mentioned above, although embodiment of this invention was described, this invention is not limited to each embodiment mentioned above, A various improvement and change are possible within the range which does not deviate from the summary of this invention.
For example, in the above-described embodiment, the gradation characteristic changing unit 13 converts the pixel value of each pixel in the image signal using a lookup table, and the dot data generating unit 14 performs the converted pixel value. Is binarized using the binarization pattern 12a. Instead, the correction characteristic represented by the lookup table is reflected in the binarization pattern 12a in advance, and the dot data generation unit 14 reflects the correction characteristic on the pixel value of each pixel in the image signal. The gradation characteristic changing unit 13 may be deleted by binarization using the binarization pattern 12a.

The technical concept of the following configuration is also derived from the above-described embodiment.
(Appendix 1)
An unfolding step of unfolding the multi-valued image in the storage area;
An image forming step of binarizing the multi-valued image developed in the storage area based on a binarized dither matrix pattern and forming an image based on the binarization result;
The binary dither matrix pattern is configured as a pattern in which a plurality of pixels that are sequentially lit are arranged in a matrix,
In the region of the binarized dither matrix pattern limited by the adjacent binarized dither matrix pattern, the first to n × nth pixels (where n is an arbitrary natural number) sequentially turned on are n N × n squares,
The pixels from the (n × n + 1) th to the (n + 1) th (n + 1) th pixel are the most in the lighting order of the first pixel among the four sides of the n × n square pixel array. The pixels from the first to the n × (n + 1) th pixel are arranged in n × (n + 1) rectangular shapes by being arranged in a row adjacent to any one of the nearby sides. ,
The pixels from the n × n + 1th to the n × (n + 1) th are arranged in order from the position in which the lighting order is close to the first pixel in one column adjacent to the side. When the distance from the first pixel is the same, the pixels are arranged in order from the position close to the middle position in the adjacent column,
The pixels from the n × (n + 1) + 1th to the (n + 1) × (n + 1) th are in the lighting order among the two long sides of the pixel array arranged in the n × (n + 1) rectangular shape. Are arranged in a row adjacent to the long side closer to the first pixel, so that (n + 1) pixels from the first to the (n + 1) × (n + 1) th are arranged. × (n + 1) square array,
The pixels from the n × (n + 1) + 1th to the (n + 1) × (n + 1) th are arranged in order from the position where the lighting order is close to the first pixel in one column adjacent to the long side. When the distance from the first pixel is the same, the adjacent pixels are arranged in order from the position close to the middle position in the adjacent column.
An image forming method.
(Appendix 2)
An unfolding step of unfolding the multi-valued image in the storage area;
An image forming step of binarizing the multi-valued image developed in the storage area based on a binarized dither matrix pattern and forming an image based on the binarization result;
The binary dither matrix pattern is configured as a pattern in which a plurality of pixels that are sequentially turned on one by one are arranged in a matrix.
In the region of the binary dither matrix pattern limited by the adjacent binary dither matrix pattern, the first to n × n−4th (n is an arbitrary natural number greater than or equal to 4) sequentially turned on. The pixels up to are arranged in a shape excluding four corners from an n × n square shape,
The n × n−3 th and n × n−2 th pixels are arranged at four adjacent corners of an n × n square shape,
The pixels from the n × n−1th to the n × (n + 1) −4th are close to the first pixel on the side that is the size of one side of the n × n square shape. The first to n × (n + 1) −4th pixels are formed by removing four corners from the n × (n + 1) rectangular shape by arranging the pixels in order from one to the other. Arranged in
The n × (n + 1) −3rd and n × (n + 1) −2th pixels are arranged at four corners of adjacent short sides of n × (n + 1) rectangular shapes,
The (n + 1) × (n + 1) −4th pixels from the (n × (n + 1) −1) th to the (n + 1) × (n + 1) squares are on the sides that are the size of one side. By arranging in order from the position close to the first pixel in one column, (n + 1) × (n + 1) × (n + 1) × (n + 1) − (n + 1) −4th pixels × (n + 1) ) It is arranged in a shape excluding four corners from a rectangular shape,
An image forming method.
(Appendix 3)
In the binary dither matrix pattern, the first to m-th pixels (m is a natural number of 2 or more) that are sequentially lit are collectively turned on in the first lighting order as a pixel block. The image forming method according to Supplementary Note 2, wherein
(Appendix 4)
A gradation characteristic changing step of changing the gradation characteristic of the multi-valued image developed in the storage area to a predetermined characteristic prepared in advance;
The image forming step binarizes the multi-valued image after the gradation characteristics are changed by the gradation characteristics changing step, and forms an image based on the binarization result.
The image forming method according to appendix 1, wherein:
(Appendix 5)
An unfolding step of unfolding the multi-valued image in the storage area;
An image forming step of binarizing the multi-valued image developed in the storage area based on a binarized dither matrix pattern and forming an image based on the binarization result;
The binarized dither matrix pattern is a pattern in which a plurality of pixels are arranged in a matrix, and a lit pixel region pattern that manages a plurality of the pixels in turn-on order and a non-lit pixel region pattern that manages the plurality of pixels in turn-off order Is configured as
The image forming step arranges the lit pixel region pattern and the unlit pixel region pattern in a checkered pattern or a pattern similar to the checkered pattern, and a pair of the lit pixel region pattern and the unlit pixel adjacent to each other in the checkered pattern arrangement Representing the gradation corresponding to the pixel value of each pixel constituting the multi-valued image by the area pattern to form the image;
An image forming method.
(Appendix 6)
Storage means for developing a multi-valued image;
Image forming means for binarizing the multi-valued image developed in the storage means based on a binarized dither matrix pattern and forming an image based on the binarization result;
The binary dither matrix pattern is configured as a pattern in which a plurality of pixels that are sequentially lit are arranged in a matrix,
In the binary dither matrix pattern, the first to n × n-th pixels (where n is an arbitrary natural number) that are sequentially lit are arranged in an n × n square shape.
An image forming apparatus.
(Appendix 7)
Storage means for developing a multi-valued image;
Image forming means for binarizing the multi-valued image developed in the storage means based on a binarized dither matrix pattern and forming an image based on the binarization result;
The binary dither matrix pattern is configured as a pattern in which a plurality of pixels that are sequentially turned on one by one are arranged in a matrix.
In the binarized dither matrix pattern, the first to n × n−4th pixels (where n is an arbitrary natural number equal to or greater than 4) that are sequentially turned on are 4 pixels from n × n square shapes. Arranged in a shape excluding the corners,
An image forming apparatus.
(Appendix 8)
In the binary dither matrix pattern, the first to m-th pixels (m is a natural number of 2 or more) that are sequentially lit are collectively turned on in the first lighting order as a pixel block. 8. The image forming apparatus according to appendix 7, which is characterized.
(Appendix 9)
Development processing for developing a multi-valued image in a storage area;
Causing the arithmetic processing device to perform binarization of the multi-valued image developed in the storage area based on the binarized dither matrix pattern and image forming processing for forming an image based on the binarization result;
The binary dither matrix pattern is configured as a pattern in which a plurality of pixels that are sequentially lit are arranged in a matrix,
In the binary dither matrix pattern, the first to n × n-th pixels (where n is an arbitrary natural number) that are sequentially lit are arranged in an n × n square shape.
An image forming processing program.
(Appendix 10)
Development processing for developing a multi-valued image in a storage area;
Causing the arithmetic processing device to perform binarization of the multi-valued image developed in the storage area based on the binarized dither matrix pattern and image forming processing for forming an image based on the binarization result;
The binary dither matrix pattern is configured as a pattern in which a plurality of pixels that are sequentially turned on one by one are arranged in a matrix.
In the binarized dither matrix pattern, the first to n × n−4th pixels (where n is an arbitrary natural number equal to or greater than 4) that are sequentially turned on are 4 pixels from n × n square shapes. Arranged in a shape excluding the corners,
An image forming processing program.
(Appendix 11)
In the binary dither matrix pattern, the first to m-th pixels (m is a natural number of 2 or more) that are sequentially lit are collectively turned on in the first lighting order as a pixel block. The image formation processing program according to appendix 10, which is characterized by the following.
(Appendix 12)
A binarized dither matrix pattern used for binarization of a multi-valued image,
It is configured as a pattern in which a plurality of pixels that are sequentially lit are arranged in a matrix.
The pixels from the first to the n × nth (where n is an arbitrary natural number) that are sequentially lit are arranged in an n × n square shape.
A binary dither matrix pattern characterized by that.
(Appendix 13)
A binarized dither matrix pattern used for binarization of a multi-valued image,
It is configured as a pattern in which a plurality of pixels that are sequentially lit one by one are arranged in a matrix.
The first to n × n−4th pixels (where n is an arbitrary natural number greater than or equal to 4) sequentially turned on are arranged in a shape excluding four corners from n × n square shapes. Yes,
A binary dither matrix pattern characterized by that.
(Appendix 14)
Item 2 according to appendix 13, characterized in that the first to m-th pixels (m is a natural number of 2 or more) that are sequentially lit are collectively turned on in the first lighting order as a pixel block. Valued dither matrix pattern.

It is a figure which shows typically the function structure of the printing system which implements this invention. It is a figure which shows typically the hardware constitutions of the printing system of FIG. It is a figure which shows the example of the correction curve represented by the look-up table of a gradation characteristic change part. It is the figure which showed the processing content of the control processing with the flowchart. It is a figure which shows an example of the production | generation result of dot data. It is the figure which showed the 1st example of the binarization dither matrix pattern. It is the figure which showed the 2nd example of the binarization dither matrix pattern. It is the figure which showed the 3rd example of the binarization dither matrix pattern. It is the figure which showed the 4th example of the binarization dither matrix pattern. It is the figure which showed the 5th example of the binarization dither matrix pattern. It is a figure which shows an example of the conventional binarization dither matrix pattern.

Explanation of symbols

1 Printing system 2 Personal computer (PC)
DESCRIPTION OF SYMBOLS 3 Printing apparatus 10 Color calculating part 11 Image signal memory 12 Pattern memory 12a Binary dither matrix pattern 13 Gradation characteristic changing part 14 Dot data generation part 15, 34 Image formation part 31 CPU
32 ROM
33 RAM

Claims (6)

An unfolding step of unfolding the multi-valued image in the storage area;
An image forming step of binarizing the multi-valued image developed in the storage area based on a binarized dither matrix pattern and forming an image based on the binarization result;
The binary dither matrix pattern is configured as a pattern in which a plurality of pixels that are sequentially lit are arranged in a matrix,
In the region of the binarized dither matrix pattern limited by the adjacent binarized dither matrix pattern, the first to n × nth pixels (where n is an arbitrary natural number) sequentially turned on are n N × n squares,
The pixels from the (n × n + 1) th to the (n + 1) th (n + 1) th pixel are the most in the lighting order of the first pixel among the four sides of the n × n square pixel array. The pixels from the first to the n × (n + 1) th pixel are arranged in n × (n + 1) rectangular shapes by being arranged in a row adjacent to any one of the nearby sides. ,
The pixels from the n × n + 1th to the n × (n + 1) th are arranged in order from the position in which the lighting order is close to the first pixel in one column adjacent to the side. When the distance from the first pixel is the same, the pixels are arranged in order from the position close to the middle position in the adjacent column,
The pixels from the n × (n + 1) + 1th to the (n + 1) × (n + 1) th are in the lighting order among the two long sides of the pixel array arranged in the n × (n + 1) rectangular shape. Are arranged in a row adjacent to the long side closer to the first pixel, so that (n + 1) pixels from the first to the (n + 1) × (n + 1) th are arranged. × (n + 1) square array,
The pixels from the n × (n + 1) + 1th to the (n + 1) × (n + 1) th are arranged in order from the position where the lighting order is close to the first pixel in one column adjacent to the long side. When the distance from the first pixel is the same, the adjacent pixels are arranged in order from the position close to the middle position in the adjacent column.
An image forming method. An unfolding step of unfolding the multi-valued image in the storage area;
An image forming step of binarizing the multi-valued image developed in the storage area based on a binarized dither matrix pattern and forming an image based on the binarization result;
The binary dither matrix pattern is configured as a pattern in which a plurality of pixels that are sequentially turned on one by one are arranged in a matrix.
In the region of the binary dither matrix pattern limited by the adjacent binary dither matrix pattern, the first to n × n−4th (n is an arbitrary natural number greater than or equal to 4) sequentially turned on. The pixels up to are arranged in a shape excluding four corners from an n × n square shape,
The n × n−3 th and n × n−2 th pixels are arranged at four adjacent corners of an n × n square shape,
The pixels from the n × n−1th to the n × (n + 1) −4th are close to the first pixel on the side that is the size of one side of the n × n square shape. The first to n × (n + 1) −4th pixels are formed by removing four corners from the n × (n + 1) rectangular shape by arranging the pixels in order from one to the other. Arranged in
The n × (n + 1) −3rd and n × (n + 1) −2th pixels are arranged at four corners of adjacent short sides of n × (n + 1) rectangular shapes,
The (n + 1) × (n + 1) −4th pixels from the (n × (n + 1) −1) th to the (n + 1) × (n + 1) squares are on the sides that are the size of one side. By arranging in order from the position close to the first pixel in one column, (n + 1) × (n + 1) × (n + 1) × (n + 1) − (n + 1) −4th pixels × (n + 1) ) It is arranged in a shape excluding four corners from a rectangular shape,
An image forming method. An unfolding step of unfolding the multi-valued image in the storage area;
An image forming step of binarizing the multi-valued image developed in the storage area based on a binarized dither matrix pattern and forming an image based on the binarization result;
The binarized dither matrix pattern is a pattern in which a plurality of pixels are arranged in a matrix, and a lit pixel region pattern that manages a plurality of the pixels in turn-on order and a non-lit pixel region pattern that manages the plurality of pixels in turn-off order Is configured as
The image forming step arranges the lit pixel region pattern and the unlit pixel region pattern in a checkered pattern or a pattern similar to the checkered pattern, and a pair of the lit pixel region pattern and the unlit pixel adjacent to each other in the checkered pattern arrangement Representing the gradation corresponding to the pixel value of each pixel constituting the multi-valued image by the area pattern to form the image;
An image forming method. Storage means for developing a multi-valued image;
Image forming means for binarizing the multi-valued image developed in the storage means based on a binarized dither matrix pattern and forming an image based on the binarization result;
The binary dither matrix pattern is configured as a pattern in which a plurality of pixels that are sequentially lit are arranged in a matrix,
In the binary dither matrix pattern, the first to n × n-th pixels (where n is an arbitrary natural number) that are sequentially lit are arranged in an n × n square shape.
An image forming apparatus. Development processing for developing a multi-valued image in a storage area;
Causing the arithmetic processing device to perform binarization of the multi-valued image developed in the storage area based on the binarized dither matrix pattern and image forming processing for forming an image based on the binarization result;
The binary dither matrix pattern is configured as a pattern in which a plurality of pixels that are sequentially lit are arranged in a matrix,
In the binary dither matrix pattern, the first to n × n-th pixels (where n is an arbitrary natural number) that are sequentially lit are arranged in an n × n square shape.
An image forming processing program. A binarized dither matrix pattern used for binarization of a multi-valued image,
It is configured as a pattern in which a plurality of pixels that are sequentially lit are arranged in a matrix.
The pixels from the first to the n × nth (where n is an arbitrary natural number) that are sequentially lit are arranged in an n × n square shape.
A binary dither matrix pattern characterized by that.