JP3698979B2 - Calibration apparatus and calibration method - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a calibration apparatus and a calibration method for performing calibration printing by recording on a photosensitive material based on image data obtained by laying out images and characters constituting a printed matter.
[0002]
[Prior art]
In the conventional process for producing printed matter, there is a calibration work for inspecting and correcting whether or not the plate-making is finished as instructed, and several proofreading work is done before the final printed matter is finished. Various proofing apparatuses for creating color prints for proofing for this proofing work are known. For example, digital image data color-separated into Y (yellow) M (magenta) C (cyan) K (black) is used. There is a calibration device for recording an image on a photosensitive material.
[0003]
As one of such proofing apparatuses, there is an apparatus for recording an image with a three-wavelength laser light source or the like on a photosensitive material provided with three color developing layers corresponding to each color plate of YMC. In the light-sensitive material having such three light emitting layers, KMC (black) color is developed by performing YMC three-color unexposed (in the case of positive) or YMC three-color full exposure (in the case of negative). Have achieved.
[0004]
By the way, in the above-described proof printing, it is preferable to faithfully reproduce the proof image in conformity with the main printing in order to confirm the color condition of the printed material. Also used to confirm. As one example of plate making work, there is a case where “trap processing” or “overlay processing” is performed in anticipation of misregistration of printed matter. This is because a part of the image is previously covered with the other image so that a gap is not exposed between the images even if there is a misregistration in the accurate joining of two or more images as referred to as “tweeping”. For example, a process or a process of placing a character image on another image as referred to as “character overlay” or the like. In the calibration work, it is preferable to be able to confirm whether or not such “trap processing” and “overlay processing” are accurately performed.
[0005]
[Problems to be solved by the invention]
In the “trap processing” and “overlay processing” as described above, images are superimposed on the printed matter. Here, in the case of a general offset printing machine or offset proofing machine, for example, the color of the area where the K color image overlaps the image of the other color and the color of the area of only the K color are the same black. Also slightly different color development. As a result, a skilled worker can also confirm the “trap process” and “placement process” as described above.
[0006]
However, when the photosensitive material having the three color-developing layers corresponding to YMC as described above is used, the K color is expressed by the unexposed or full exposure of the YMC three colors. The same color was generated in the region where the colors overlapped, and it was not possible to confirm “trap processing” or “overlay processing” using the K color. For this reason, even if the instructed plate making process is unprocessed, there is a possibility of being overlooked.
[0007]
The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a calibration method and a calibration apparatus that can easily check a region in which the K color overlaps with other colors, and particularly corresponds to YMC. An object of the present invention is to provide a calibration apparatus and a calibration method that are optimum when a photosensitive material having three color-developing layers is used.
[0008]
[Means for Solving the Problems]
The invention according to claim 1 is a proofreading apparatus for obtaining a proof print by performing exposure for each color on a photosensitive material having at least three color developing layers corresponding to each color plate of YMC, Among image data obtained by binarizing one image data by a predetermined RIP processing means, A determination unit that compares the image data of the K plate and the image data of the other color plate for each pixel to determine whether the pixel of the K plate overlaps any pixel of the other color plate; In the case where it is determined that the pixels in FIG. Pixel value is 0 Missing pixel conversion means for performing pixel conversion so as to become missing pixels.
[0009]
According to a second aspect of the present invention, in the calibration apparatus according to the first aspect, the pixel conversion is performed at a pixel interval determined along the main scanning direction.
[0010]
According to a third aspect of the present invention, in the calibration apparatus according to the second aspect, the pixel interval can be selected from a predetermined value.
[0011]
According to a fourth aspect of the present invention, in the calibration apparatus according to the second or third aspect, the determination unit performs the determination for each main scanning line having a substantially same interval as the pixel interval in the sub-scanning direction. It is characterized by having done.
[0012]
According to a fifth aspect of the present invention, in the calibration device according to any one of the first to fourth aspects, the missing pixel conversion means corresponds to a line memory having a predetermined address length and each address of the line memory. A missing pixel position setting means capable of setting the position of a missing pixel, and a line memory reading means for reading out values in the line memory in order of addresses in synchronization with a timing determined by the determination means. According to the present invention, the K-version pixel is subjected to pixel conversion in accordance with the value read by the reading means.
[0013]
According to a sixth aspect of the present invention, in the calibration apparatus according to the fifth aspect, the line memory reading means cyclically reads the line memory.
[0014]
According to a seventh aspect of the present invention, in the calibration apparatus according to the fifth or sixth aspect, the line memory reading unit changes a read start address for each corresponding main scanning line.
[0015]
According to an eighth aspect of the present invention, in the calibration apparatus according to the first aspect, the missing pixel position setting means arranges the missing position by a random number.
[0016]
According to a ninth aspect of the present invention, in the calibration apparatus according to any one of the first to third aspects, the number of times that the missing pixel converting unit determines that the K plane pixel overlaps with the other plane pixel by the determining unit. And every time the count reaches a predetermined value, the corresponding K plate pixel is converted into a missing pixel.
[0017]
The invention according to claim 10 is a proofing device that performs color proofing printing based on image data, Among image data obtained by binarizing one image data by a predetermined RIP processing means, When the image data of the K plate and the image data of the other color plate are compared for each pixel to determine whether the pixel of the K plate overlaps any pixel of the other color plate, and when it is determined that they overlap In the above, the K plate pixels at a predetermined ratio Pixel value is 0 A first mode in which pixel conversion is performed so as to be a missing pixel, and a second mode in which the pixel conversion is not performed on K-version image data without performing the determination, and one of the modes is selectively selected It is feasible.
[0018]
The invention according to claim 11 is a calibration method capable of confirming an overlapping state between the K plate and another color plate using a calibration device that performs color proof printing based on image data, By binarizing one image data by a predetermined RIP processing means Preparing image data for each color plate; Between the color plates, A determination step of comparing the image data of the K plate and the image data of the other color plate for each pixel to determine whether the pixel of the K plate overlaps any pixel of the other color plate; and the determination step If it is determined that the pixels overlap, the K plate pixels are Pixel value is 0 A missing pixel conversion step of converting the pixels so as to become missing pixels.
[0019]
According to a twelfth aspect of the present invention, in the calibrating method according to the eleventh aspect, the calibrating apparatus exposes a photosensitive material having three color developing layers corresponding to three colors of YMC, The color is expressed by YMC three-color unexposed or three-color full exposure.
[0020]
According to a thirteenth aspect of the present invention, in the calibration method according to the eleventh or twelfth aspect, the missing pixel conversion step performs pixel conversion at predetermined pixel intervals that are selectively determined in advance. Features.
[0021]
According to a fourteenth aspect of the present invention, in the calibration method according to the thirteenth aspect, the missing pixel conversion step performs pixel conversion at regular pixel intervals along the main scanning direction, and in the sub scanning direction. The determination step is performed with an interval substantially the same as the pixel interval.
[0022]
The invention according to claim 15 is the calibration method according to claim 11 or 12, wherein the missing pixel conversion step performs pixel conversion in a random manner according to a preset probability. To do.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
[Principle of the present invention]
First, the principle of confirming the overlapping state of the K plate and other color plates in the present invention will be described. In the following description, an example in which a positive photosensitive material having three color developing layers corresponding to YMC is used as a photosensitive material for forming an image will be described. Each image is formed of a binary image. FIG. 6A is a diagram showing an example in which the K version letter “E” is placed on a halftone area m composed of 50% halftone dots of the M version. In the conventional example, the left half of the letter “E” on the halftone area m and the right half of the letter “E” on the paper white area h (an area where there is no other color image) are the same K color. It becomes.
[0024]
On the other hand, in the present invention, as shown in FIG. 6B, in the place where the halftone dot on the halftone area m exists, the K plate image is missing every four pixels to form a pixel. That is, the K version image has no pixel at an interval of 4 pixels (pixel value is 0, hereinafter referred to as “missing pixel”), and the overlapped M version pixels can be visually recognized in that portion. In the calibration apparatus according to this embodiment, the one pixel has a size of about 10 μm with a resolution of 2400 dpi. Accordingly, as shown in FIG. 6C, the M plate is visible through the human eye as if it were the base.
[0025]
As described above, in the proofreading apparatus of the present invention, when the K plate pixel overlaps with the other color plate pixels, the other color plate overlapped with the K plate is obtained by replacing the K plate pixels at a predetermined ratio. Can be visually recognized. Hereinafter, the normal mode is output as in FIG. 6A, and the mode in which missing pixels are formed on the K plate and the overlapping state of the K plate can be confirmed as shown in FIG. 6C is confirmed. This is called a mode.
[0026]
[Embodiment of calibration apparatus]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view of the calibration apparatus. In FIG. 1, the calibration apparatus includes a drum 1 capable of holding a photosensitive material on its peripheral surface, supply means 2 and discharge means 3 for supplying and discharging photosensitive material to and from the drum, and photosensitive material on the drum 1. It comprises a recording means 4 for recording a color image, and a control means (5 in FIG. 2) for controlling each of the above parts and processing the image data.
[0027]
The drum 1 is a cylindrical member that can hold a sheet-like photosensitive material on its peripheral surface, and is configured to be rotatable by a drive motor (not shown). The supply means 2 includes cassettes 10 and 11 having two types of roll-shaped photosensitive materials having different width sizes, and sheet conveyance that cuts the photosensitive material drawn from each of the cassettes 10 and 11 into a sheet shape and conveys the sheet to the drum 1. Means 12. Here, the photosensitive material is a photosensitive material provided with three color developing layers corresponding to YMC. The discharging means 3 peels the recorded photosensitive material from the drum 1 and discharges it to a subsequent developing device (not shown). In the discharge means 3 in the present embodiment, the photosensitive material is discharged with the recording surface facing downward, and therefore a reversing means 13 for reversing the front and back of the photosensitive material before being fed to the developing device is provided. The recording unit 4 includes a recording head 14 for recording a color image having a light source of three wavelengths of RGB, and a feeding unit 15 for driving the recording head 14 along the axial direction of the drum 1. In the following description, the rotation direction of the drum 1 is the main scanning direction, and the moving direction of the recording head 14 is the sub-scanning direction.
[0028]
The control means 5 is a computer system including a CPU and memory, display means such as a CRT, input means such as a mouse and keyboard, storage means such as a hard disk, buffer memory, etc. In this embodiment, the calibration device It is programmed to perform its own control and image data processing.
[0029]
The configuration related to the image function of the control means 5 will be described with reference to the block diagram of FIG. In the figure, the control means 5 is processed with the RIP processing means 20 for performing RIP processing (Raster-Image-Processing) on the image data D0 created by a DTP (desk-top-publishing) device (not shown) in the previous stage. Storage means 21 for storing binary image data D1, missing pixel conversion means 22 for forming missing pixels from the stored binary image data D1 into K-plane image data, and missing pixel conversion means 22 RGB conversion means 23 for performing RGB conversion on the image data D2 converted in Step 1, a data buffer 24 for temporarily storing binary image data D3 generated by the RGB conversion means 23, and a binary image stored in the data buffer 24 The driver 25 drives the recording head 14 based on the data D3.
[0030]
The RIP processing means 20 converts the image data into binary image data D1 represented in a bitmap format for each color plate of YMCK. The binary image data D1 after the RIP process is sent out as image data for each color plate. In this embodiment, the RIP processing is performed on the calibration device side, but the processing may be performed by the preceding image data creation device or the like. The storage means 21 includes a hard disk device having a storage capacity capable of storing the binary image data D1 for each color plate for four colors. The storage unit 21 may include compression / decompression unit that compresses and stores image data, decompresses and reads the image data.
[0031]
The missing pixel conversion means 22 forms missing pixels for the K plane image data in the K plane confirmation mode. Details of this will be described later with reference to FIG. In the normal mode, no conversion is performed on the K version image data. The RGB conversion means 23 generates RGB image data D3 by subjecting the YMCK color image data to RGB conversion in accordance with the three-wavelength light source of the recording head 14. Note that the RGB conversion is a known technique, and generates RGB image data corresponding to a combination of YMCK predetermined color image data, and is described in, for example, Japanese Patent Publication No. 7-22346. Explanation here is omitted.
[0032]
The data buffer 24 is a memory device for buffering the RGB-converted binary image data D3 for each predetermined block. In this embodiment, the image data D3 for each main scanning 128 lines is converted into the RGB conversion means 23. Are sent to the data buffer 24 and buffered. The next driver 25 is means for controlling on / off of each light source in the recording head 14 based on the image data D3 stored in the data buffer, thereby recording an image on the photosensitive material on the drum 1. Can do.
[0033]
As described above, the control means 5 is a system including a microcomputer, but each means may be configured by a separate computer system. In addition to the image processing described above, the control means 5 also performs control processing for each part of the proofing device, communication control processing with the subsequent developing device, and the like, but the description thereof is omitted here.
[0034]
In the above embodiment, the data buffer 24 is arranged after the RGB conversion means 23, but this order may be reversed. That is, first, binary image data D2 (or D1) having an appropriate block size may be read from the data buffer 24, and the RGB data may be sequentially converted by the RGB conversion unit 23 accordingly.
[0035]
Next, the configuration of the missing pixel conversion means 22 according to the present invention will be described with reference to the functional block diagram of FIG. First, the missing pixel conversion means 22 includes an array memory 30 composed of a line memory having a predetermined address length, and a missing pixel position setting means 31 for writing bit information to the array memory 30. The array memory 30 is a line memory as shown in FIG. 6D, for example, and bit information “0” or “1” is written in each address. The address length of the line memory is set to be the same as or smaller than the length of the maximum image data to be recorded in the main scanning direction.
[0036]
The missing pixel position setting means 31 sets bit information “0” or “1” on each address of the array memory 30. For example, if the ratio of missing pixels formed on the above-described K plane image data is 1/4 in the main scanning direction and the sub-scanning direction, the missing pixel position setting means 31 is set to “ 1 "bit information is set. The ratio of the missing pixels can be selected in advance by a worker from a plurality of numerical values. The ratios in the main scanning direction and the sub-scanning direction are preferably the same in view of the uniformity of image processing, but different ratios may be set.
[0037]
Further, the missing pixel converting means 22 is an image data sending means 32 for sending the YMCK binary image data D1 from the storage means 21, and a judging means 33 for judging pixel overlap based on the sent image data D1. And an array memory reading means 34 for reading the bit information from the array memory 30 based on the determination result and generating a conversion command signal, and converting the pixels of the K image data into missing pixels based on the conversion command signal. Pixel conversion means 35.
[0038]
The image data sending means 32 skips the main scanning line for missing pixel conversion processing in the sub-scanning direction according to the ratio of missing pixels set by the missing pixel position setting means 31. For example, when the ratio of missing pixels is 1/4 in both the main scanning direction and the sub-scanning direction as described above, missing pixel conversion is performed at intervals of four main scanning lines in the sub-scanning direction as shown in FIG. Good. That is, missing pixel conversion is not necessary for the three main scanning lines between the main scanning lines to be converted, and therefore K image data is sent as it is to the data buffer 24 as shown in FIG. . On the other hand, in the case of the main scanning line to be converted, the image data sending means 32 sends the YMCK image data D1 to the judging means 33, and the K conversion image data is shown in the direction B in the figure. 35. In any of the above cases, the YMC image data is not converted and is sent to the data buffer 24 as shown in FIG.
[0039]
Such a skip operation includes, for example, a counter (not shown) in the image data sending means 32, counts the counter every time the main scanning line is processed, and the missing pixel every time the count value reaches the ratio. What is necessary is just to send image data for conversion. Alternatively, the missing pixel position setting unit 31 or the like may instruct skipping at a timing according to the ratio. When there is no missing pixel conversion as in the normal mode, the missing pixel position setting means 31 indicates to the image data sending means 32 all the YMCK image data without missing pixel conversion and is shown in the direction A in FIG. To send data to the data buffer 24.
[0040]
If the skip processing as in this embodiment is performed, there is an advantage that the time required for the conversion of the image data can be shortened. However, in all cases, all the image data is sent to the determination unit 33, and the determination result of the determination unit 33 is always “no pixel overlap” in the main scanning line where no missing pixel conversion is performed. You may make it process.
[0041]
The determination unit 33 determines whether or not the K plane pixel and the YMC pixel overlap each other based on the YMCK image data D1. This determination is made sequentially for each pixel in the main scanning direction. When the pixel value of the K plate is “1” and any pixel value of YMC is “1”, it is determined that there is an overlap, and a read command signal is output to the array memory reading means 34. On the other hand, if it is determined that there is no overlap, a conversion unnecessary signal is output to the pixel conversion means 35.
[0042]
The array memory reading means 34 reads the bit information of the array memory 30 in response to the read command signal from the judging means 33. When the bit information of “1” is read, the conversion command signal is converted into the pixel conversion means. When the bit information “0” is read out, a conversion unnecessary signal is output to the pixel conversion means 35. Note that this reading is performed by sequentially incrementing the address of the array memory 30, and when the reading reaches the final address, it cyclically returns to the start address. Thereby, the address length of the array memory 30 can be set shorter than the main scanning line length. As a matter of course, if the address length of the array memory 30 is equal to or longer than the main scanning line length, the cyclic use as described above may not be performed.
[0043]
The pixel conversion means 35 processes the K version image data for each pixel in response to the input of the conversion unnecessary signal or the conversion command signal. When the conversion command signal is input, the pixel value is set to “1”. Is converted from “0” to “0”, and when a conversion unnecessary signal is input, the pixel value is not converted.
[0044]
In the missing pixel conversion means 22, missing pixels can be set based on the bit information set in the array memory 30. In the above example, the bit information set in the array memory 30 is arranged at fixed pixel intervals, but may be randomly arranged according to the set ratio. For example, it is effective when there is a possibility that a moire pattern or the like is generated due to a fixed arrangement of missing pixels. Further, the reading start address of the array memory 30 may be appropriately changed for each main scanning line.
[0045]
Next, the operation of the calibration apparatus will be described with reference to the flowcharts of FIGS. FIG. 4 is a flowchart showing the overall work flow for performing calibration output, and FIG. 5 is a flowchart showing the flow of image data conversion accompanying the missing pixel conversion. First, in step S1, an initial setting for performing calibration work is performed. In this initial setting, it is possible to set the output mode switching between the normal mode for outputting the K plate as usual and the confirmation mode for confirming the overlapping state of the K plate, and the ratio of missing pixels in the confirmation mode. In addition, as other settings, selection of image data to be printed, setting of the number of output sheets, output size, and the like are also performed.
[0046]
In step S <b> 2, a photosensitive material is supplied to the drum 1. That is, the photosensitive material is cut out from the cassette magazine 10 or 11 according to the output size and wound around the drum 1. In step S3, the output mode is confirmed. If the output mode is the normal mode, the process proceeds to step S4 and normal image data conversion is performed. That is, the image data D0 is RIP processed and converted to binary image data D1 of YMCK, and then converted to image data D3 by RGB conversion. In the case of the confirmation mode, the process proceeds from step S3 to step S5, and image data conversion including missing pixel conversion is performed. That is, the image data D0 is RIP processed and converted to binary image data D1 of YMCK, then converted to image data D2 by missing pixel conversion, and finally converted to image data D3 by RGB conversion.
[0047]
In step S6, exposure is performed based on the image data converted in step S4 or S5. When the exposure is completed, the photosensitive material is discharged from the drum 1 in step S7, and then developed in a subsequent development processing apparatus in step S8.
[0048]
In the above flow, each process is shown in series for easy understanding, but if possible, each process may be processed in parallel or a predetermined process may be moved back and forth. For example, the image data may be converted prior to the supply of the photosensitive material in step S2. Further, the image data may be converted and the exposure may be performed in parallel with the image data that has been sequentially converted.
[0049]
Subsequently, only the process of missing pixel conversion from the image data conversion in step S5 will be described. First, at step P1, the array memory 30 is prepared. That is, bit information “1” indicating the timing for setting missing pixels is written on the array memory 30 in accordance with the set missing pixel ratio. From step P2, the overlap of the K color pixel and the YMC pixel is sequentially judged in the corresponding main scanning direction. If there is an overlap between the corresponding pixels, the process proceeds to step P3. If not, the process proceeds to step P6 without performing conversion of the corresponding K plate pixel.
[0050]
In step P3, the array memory 30 is read sequentially. In step P4, if the read bit information is “1”, it is determined that it is a missing pixel conversion position, and the process proceeds to step P5. If “0”, the corresponding K version pixel is not converted and step P6 is not performed. Proceed to In step P5, the corresponding K pixel is converted from “1” to “0” to form a missing pixel. In step P6, it is determined whether or not processing has been completed for all pixels on the corresponding main scanning line. If processing has been completed, the process proceeds to step P7. If processing has not been completed, processing is performed in step P8. The pixel address is incremented to the next pixel, and the process returns to Step P2.
[0051]
When the conversion in the corresponding main scanning line is completed, the main scanning line is skipped in step P7 according to the ratio. In step P9, it is determined whether or not processing has been completed for all main scanning lines. If it is determined that all lines have been completed, this flow ends. If a main scanning line that has not yet been processed remains, the pixel address in the main scanning direction, the read address of the array memory, and the like are reset, and the process returns to step P2.
[0052]
[Other embodiments]
(1) The missing pixel conversion may be performed by performing a logical operation on the bit information set in the array memory 30 and the pixel value of the K version image data. For example, the bit information to be set in the array memory 30 is set to “0” when there are missing pixels, “1” when there is no missing pixel, and the bit information read by the array memory reading means 34 and the K image data What is necessary is just to take a logical product with a pixel value.
[0053]
(2) The address of the array memory 30 is configured to be sequentially incremented when the K version pixels overlap, but it is macroscopic even if configured to increment each time each pixel is determined. Have the same effect.
[0054]
(3) As the array memory 30, a memory with line-shaped address setting is used, but a memory with two-dimensional address setting may be used. Further, the interval for setting missing pixels may be counted using a predetermined counter without using the array memory 30. For example, a configuration may be considered in which the number of times that the K plate pixel overlaps with the other plate pixels is counted by a counter and is changed to a missing pixel every predetermined number of times.
[0055]
【The invention's effect】
According to the first aspect of the present invention, when the K plate pixel and another color plate pixel overlap, the K plate pixel is changed to a missing pixel at an appropriate ratio. It is possible to visually recognize an image of another color as if it is watermarked. As a result, it is possible to confirm plate making operations such as trap processing and letter placement.
[0056]
According to the second aspect of the present invention, since conversion to missing pixels can be performed at a predetermined fixed pixel interval, conversion work can be simplified.
[0057]
According to the third aspect of the present invention, since the pixel interval can be changed, the degree of transmission of other color plates overlapping the K plate can be changed.
[0058]
In the fourth aspect of the invention, since a predetermined number of main scanning lines are skipped in the sub-scanning direction, the image conversion process can be shortened.
[0059]
Since the invention according to claim 5 is used for setting the missing pixel position in the line memory, various missing pixel arrangement patterns can be easily set.
[0060]
The invention according to claim 6 can use a small line memory by cyclically using the line memory.
[0061]
According to the seventh aspect of the present invention, it is possible to prevent the missing pixel arrangement pattern from becoming uniform by a simple method by appropriately changing the missing pixel position in the main scanning direction.
[0062]
According to the eighth aspect of the present invention, the possibility of the occurrence of a moire pattern can be reduced by setting the arrangement of missing pixels as a random number.
[0063]
According to the ninth aspect of the invention, there is an effect that it is not necessary to provide a line memory for setting the arrangement of missing pixels.
[0064]
In the invention according to claim 10, since it is possible to switch between the first mode in which the superposition state of the K plate can be observed and the normal second mode, for example, if the confirmation of the plate making operation is the main, the first mode If the main purpose is to check the mode, color, etc., the second mode can be switched according to the purpose.
[0065]
In the inventions according to claims 11 and 12, when the K plate pixel and another color plate pixel overlap, the K plate pixel is changed to a missing pixel at an appropriate ratio. It is possible to visually recognize an image of another color as if the K version was watermarked. As a result, it is possible to confirm the plate making work such as trap processing and letter placement. In particular, a photosensitive material having three color-developing layers on which the superimposed state of the K color on the YMC is difficult to distinguish is highly effective.
[0066]
In the invention according to the thirteenth aspect, conversion to missing pixels can be performed at a predetermined fixed pixel interval, so that the conversion work can be simplified.
[0067]
In the invention described in claim 14, since a predetermined number of main scanning lines are skipped in the sub-scanning direction, the image conversion process can be shortened.
[0068]
According to the fifteenth aspect of the present invention, it is possible to reduce the possibility of the occurrence of a moire pattern by setting a random pixel layout.
[Brief description of the drawings]
FIG. 1 is a schematic side view of a calibration device according to an embodiment of the present invention.
FIG. 2 is a block diagram of a control unit that controls image data processing in the calibration apparatus.
FIG. 3 is a functional block diagram of missing pixel conversion means in the control means.
FIG. 4 is a flowchart showing an operation process of the calibration apparatus.
FIG. 5 is a flowchart showing a missing pixel conversion process.
FIG. 6 is an explanatory diagram relating to missing pixels.
[Explanation of symbols]
1 drum
2 Supply means
3 Discharge means
4 Recording means
5 Control means
14 Memory head
22 missing pixel conversion means
30 array memory
31. Missing pixel position setting means
32 Image data sending means
33 Judgment means
34 Array memory reading means
35 pixel conversion means

Claims (15)

A proofing device that obtains proof printing by performing exposure for each color on a photosensitive material having at least three color developing layers corresponding to each color plate of YMC,
Between the image data obtained by binarizing one image data by a predetermined RIP processing means, the K plate image data and the other color plate image data are compared for each pixel, and the K plate A judging means for judging whether or not the pixel overlaps any pixel of another color plate;
A calibration apparatus comprising: missing pixel conversion means for performing pixel conversion so that the pixels of the K plate become missing pixels having a pixel value of 0 at a predetermined ratio when it is determined by the determination means to overlap. The calibration apparatus according to claim 1, wherein the pixel conversion is performed at a pixel interval determined along a main scanning direction. The calibration apparatus according to claim 2, wherein the pixel interval is selectable from a predetermined value. 4. The calibration apparatus according to claim 2, wherein the determination unit performs the determination for each main scanning line having an interval substantially the same as the pixel interval in the sub-scanning direction. The missing pixel conversion means includes
A line memory having a predetermined address length;
A missing pixel position setting means capable of setting a position of a missing pixel corresponding to each address of the line memory;
Line memory reading means for reading values in the line memory in the order of addresses in synchronization with the timing determined by the determining means,
5. The calibration apparatus according to claim 1, wherein the K-version pixel is subjected to pixel conversion in accordance with a value read by the line memory reading means. 6. The calibration apparatus according to claim 5, wherein the line memory reading means reads the line memory cyclically. 7. The calibration apparatus according to claim 5, wherein the line memory reading means changes a reading start address for each corresponding main scanning line. 2. The calibration apparatus according to claim 1, wherein the missing pixel position setting means arranges the missing position by a random number. The missing pixel conversion means counts the number of times that the judgment means judges that the K plate pixel overlaps with the other version pixel, and every time the count reaches a predetermined value, the corresponding K plate pixel is determined as a missing pixel. The calibration apparatus according to claim 1, wherein the calibration is performed. A proofing device that performs color proofing printing based on image data,
Between the image data obtained by binarizing one image data by a predetermined RIP processing means, the K plate image data and the other color plate image data are compared for each pixel and the K plate pixel Is determined to overlap with any other pixel of the other color plate, and if it is determined to overlap, the pixel of the K plate is a missing pixel having a pixel value of 0 at a predetermined ratio. A first mode to convert;
And a second mode in which the pixel conversion is not performed on the K-plane image data without performing the determination, and a calibration apparatus capable of selectively executing any mode. A calibration method capable of confirming an overlapping state between a K plate and another color plate using a proofing device that performs color proof printing based on image data,
Preparing image data of each color plate by binarizing one image data by a predetermined RIP processing means ;
Between each of the color plates, the image data of the K plate and the image data of the other color plate are compared for each pixel to determine whether the K plate pixel overlaps any pixel of the other color plate. A decision process;
A calibration method comprising: a missing pixel conversion step of performing pixel conversion so that pixels of the K plate are converted to missing pixels having a pixel value of 0 at a predetermined ratio when it is determined that pixels overlap in the determination step. The calibration device exposes a photosensitive material having three color layers corresponding to three colors of YMC, and K color is expressed by three unexposed YMC colors or full exposure of three colors. The calibration method according to claim 11, wherein there is a calibration method. 13. The calibration method according to claim 11 or 12, wherein the missing pixel conversion step performs pixel conversion at predetermined pixel intervals that are selectively determined in advance. In the missing pixel conversion step, the pixel conversion is performed at regular pixel intervals along the main scanning direction, and the determination step is performed at substantially the same interval as the pixel intervals in the sub scanning direction. The calibration method according to claim 13, wherein the calibration method is performed. 13. The calibration method according to claim 11, wherein the missing pixel conversion step performs pixel conversion in a random manner according to a preset probability.

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