KR20050073182A - Color registration pattern generator for use in color image former - Google Patents

Abstract

The present invention relates to a color registration pattern generating apparatus of a color image forming apparatus. More specifically, by providing a color registration pattern that can adjust the x-offset in the subdot unit when the main scan direction color registration of the tandem type color laser printer is performed, the color registration is precisely performed in the sub-dot unit. It relates to a color matching pattern generating device that can fit. The color matching pattern generator of the color image forming apparatus is synchronized with a horizontal sync signal from the LSU, and further includes a line sync (x-offset value in dot and subdot units). line sync) and a video clock, and receive information corresponding to the line position of the pattern in real time when generating the pattern from the color matching pattern generator, and additionally reflect the x-offset value in sub-dot units. Video clock generator; And a plurality of color matching pattern generators generating information corresponding to the line position of the pattern currently generated in real time as a pattern matching pattern in the scan direction and transmitting the generated color matching pattern to the video clock generator.

Description

Color registration pattern generator for color image forming apparatus {Color registration pattern generator for use in color image former}

The present invention relates to a color registration pattern generating apparatus of a color image forming apparatus. More specifically, by providing a color registration pattern that can adjust the x-offset in the subdot unit when the main scan direction color registration of the tandem type color laser printer is performed, the color registration is precisely performed in the sub-dot unit. It relates to a color matching pattern generating device that can fit.

In general, an apparatus for generating a color registration pattern according to the related art includes a plurality of laser scan units (LSUs) for exposing a photosensitive medium to form a latent image, and a plurality of photosensitive media for forming a latent image in response to exposure of the LSU. And a plurality of developing units, one for each color for forming a toner image on the latent image formed on the photosensitive medium, synchronized with line sync of the LSU, and dot and subdot. X-offset adjustment of the unit, video clock generator and video scan frequency that can vary the video clock frequency per unit block by dividing a line into several unit blocks The color registration pattern generator includes a color registration pattern generator for generating a pattern used for color registration manual adjustment in the scan direction.

In the present specification, the entire system block diagram including the system control unit including the LSU, the photosensitive medium, and the developing unit is omitted, and a block diagram illustrating the video clock generator and the color matching pattern generator of FIG. 1 and a conventional line of FIG. The prior art will be described with reference to a waveform diagram showing a video clock (vclk) generated by the synchronization and video clock generator and a waveform diagram showing an example of the conventional color matching pattern of FIG. 3.

Conventional tandem color laser printers include a plurality of laser scan units (LSUs) for exposing a photosensitive medium to form a latent image, a plurality of photosensitive media for forming a latent image in response to the exposure of the LSU, and a latent image formed on the photosensitive medium. It is composed of a plurality of developing units for forming a toner image, but as described above, the overall description of the operation of the tandem type color laser printer is omitted, and the video clock generator and scan of FIG. 1 directly related to the present invention will be described below. Directional Color Matching A conventional operation will be described with reference to a color matching pattern generator for manual adjustment.

The video clock generator 10 shown in FIG. 1 is a block for generating a video clock (vclk) used when scanning printed image data into an LSU, and has the following functions.

As shown in FIG. 1, the video clock generator 10 generates a video clock in synchronization with a hsync sync from the LSU. The video clock generator 10 also includes a line sync in which the x-offset register 12 and the video clock synthesizer 14 reflect an x-offset in units of dots and subdots. Generates a signal. This line synchronization is a synchronization signal that is a reference for scanning printed image data into the LSUs per line. By dividing one line into several unit blocks, the video clock frequency can be minutely changed for each block, so that one line middle region can match the scan direction color matching.

The color matching pattern generator 20 of FIG. 1 receives page sync from the system controller (not shown) and line sync and video clock vclk from the video clock generator 10. Similarly, a color registration pattern for manually adjusting the scan direction color registration is generated. In reality, the blocks shown in FIG. 1 exist independently for each color.

FIG. 2 is a diagram illustrating line sync, video clock vclk waveforms, and phase relations based on horizontal sync (hsync) input from an LSU. On the basis of the horizontal sync (hsync), the time when line sync occurs every line is the same.

3 is a diagram showing an example of a color matching pattern output image. An example is a color registration pattern for black and cyan colors. The black color is a pattern consisting of dotted lines and diagonal lines and the cyan color is a vertical line pattern. Cyan Color Finds the black dotted pattern number (PAT_NOn) that best matches the vertical line to match the relative scan direction color registration between black and cyan.

In FIG. 3, the cyan vertical line pattern overlaps the pattern number 2 (PAT_NO2) and the pattern number 3 (PAT_NO3) in half. Based on the pattern number determined above, the system controller sets an appropriate value to the x-offset register 12 of the video clock generator. The pattern with the black dotted line pattern and the yellow (or magenta) vertical line is omitted in FIG. 3 but has the same configuration as above.

The color matching pattern generator 20 generates a color matching pattern by receiving a video clock (vclk), which is a unit of one dot, and as shown in FIG. 3, the cyan (yellow or magenta) vertical line has a pattern number 2 of the black dotted pattern. If (PAT_NO2) and pattern number 3 (PAT_NO3) are matched in half, it may be difficult for the user to determine which number to select. In FIG. 3, the case of 0.5 dot matching is taken as an example, but there are many cases where overlapping occurs at a rate that is more difficult to determine. This problem occurs because the color matching pattern can only be implemented in units of 1 dot.

As a prior art, Japanese Patent Laid-Open No. 13-109218 discloses a technique for judging and correcting the number of pixels necessary for correction by superimposing another test pattern on one test pattern. 096780 discloses a technique for raising the number of gray scales by generating a clock vclk with a plurality of phase shifts in order to accurately represent the gray scales of input image data, and selecting one of them. 264485 discloses a technique for adjusting an error adjusting pattern at a low resolution and then outputting it to one recording medium after adjusting the error adjusting pattern at a high resolution. In addition, Japanese Patent Laid-Open Nos. 08-118737 and 10-115962 are disclosed. The technique does not disclose at all the color matching pattern in sub-dot units.

The technical problem to be achieved by the present invention is to solve the above-mentioned disadvantages of the prior art, by implementing a black dotted line pattern in the sub-dot unit of the scan direction color registration pattern for manual adjustment to form a color image to facilitate the scan direction color registration adjustment It is an object of the present invention to provide a color matching pattern generating device.

The present invention, in order to achieve the above technical problem, a plurality of laser scan unit (LSU) for exposing the photosensitive medium to form a latent image; A plurality of photosensitive media forming a latent image in response to exposure of the LSU; And a plurality of developing units, one for each color for forming a toner image on the latent image formed on the photosensitive medium, wherein the color matching pattern generating device of the color image forming apparatus comprises: a horizontal sync (hsync) from the LSU Generates a line sync signal and a video clock synchronized with the signal and reflecting the x-offset value in the unit of dot and subdot, and also the pattern from the following color matching pattern generator A plurality of video clock generators which receive information corresponding to the line position of the pattern in real time and additionally reflect the x-offset value in sub-dot units; And a plurality of color matching pattern generators generating information corresponding to the line position of the currently generated pattern in real time as a pattern matching pattern in the scan direction and transmitting the information to the video clock generator during pattern generation. Provided is a pattern matching apparatus.

Preferably, the color matching pattern in the scan direction has a scan direction interval between the individual patterns in the entire pattern as shown in the example of FIG. 6 in a dot or subdot unit interval or in a subdot unit. The pattern consists of gaps.

Preferably, the information corresponding to the line position for the pattern is the pattern number PAT_NOn of each individual pattern as in the example of FIG. 6.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The tandem type color laser printer to which the present invention is applied includes a plurality of laser scan units (LSUs) for exposing a photosensitive medium to form a latent image, a plurality of photosensitive media for forming a latent image in response to the exposure of the LSUs, and the photosensitive medium image. Although it is composed of a plurality of developing units for forming a toner image on the latent image formed therein, the overall operation description of the tandem type color laser printer is omitted here, as described above, and the video clock of FIG. 4 which is directly related to the present invention will be described below. Generator and Scan Direction Color Matching The following description will focus on a color matching pattern generator for manual adjustment.

First, the system of the color registration pattern generating apparatus of the color image forming apparatus to which the present invention is applied will be described. The color matching pattern generating device of the present invention comprises: a plurality of laser scan units (LSUs) for exposing a photosensitive medium to form a latent image; A plurality of photosensitive media forming a latent image in response to exposure of the LSU; A plurality of developing units, one for each color for forming a toner image on a latent image formed on the photosensitive medium; It generates a line sync signal and a video clock synchronized with a horizontal sync signal from the LSU and reflecting an x-offset value in units of dots and subdots. And a plurality of video clock generators receiving information corresponding to the line position of the pattern in real time when generating the pattern from the color matching pattern generator, and additionally reflecting the x-offset value in sub-dot units; And a plurality of color matching pattern generators generating information corresponding to the line position of the pattern currently generated in real time as a pattern matching pattern in the scan direction and transmitting the generated color matching pattern to the video clock generator.

The tandem type color laser printer to which the present invention is applied includes a plurality of laser scan units (LSUs) for exposing a photosensitive medium to form a latent image, a plurality of photosensitive media for forming a latent image in response to the exposure of the LSU, and the photosensitive medium. Although it is composed of a plurality of developing units, one for each color for forming a toner image on a latent image formed on the image, the overall operation description of the tandem type color laser printer is omitted here, and a video clock generator is directly related to the present invention hereinafter. The operation of the present invention will be described with reference to the color matching pattern generator for manual adjustment of scan direction color matching.

In other words, in the present specification, as described above, the entire system block diagram including the system control unit including the LSU, the photosensitive medium, and the developing unit is omitted, and the video clock generator and the color matching pattern which are directly related to the present invention. The generator will be described in more detail with reference to FIGS. 4 to 6.

The video clock generator 100 of FIG. 4 is synchronized with the line synchronization from the LSU through the x-offset register 12 and the video clock synthesizing unit 14, and the x-offset in dot and subdot units. (x-offset) can be adjusted, and the video clock frequency can be varied for each unit block by dividing one line into several unit blocks, and in real time when the pattern is generated from the color matching pattern generator 200 as shown in FIG. The information on the pattern number PAT_NOn of the dotted line pattern is received and additionally reflected to the x-offset determiner 112. In addition, the color matching pattern generator 200 generates a pattern used for color matching manual adjustment in the stan direction, and feeds back the pattern number PAT_NOn of the black dotted line pattern among the patterns to the video clock generator 100 in real time during pattern generation. do.

The video clock generator 100 shown in FIG. 4 is a block for generating a video clock used when scanning printed image data into an LSU, and has the following functions.

The video clock generator 100 generates a video clock in synchronization with the hsync sync from the LSU. The x-offset determiner 112 in the video clock generator 100 generates a line sync signal that reflects the x-offset in units of dots and subdots. This line synchronization is a synchronization signal that is a reference for scanning printed image data into the LSUs per line. Conventionally, there is an x-offset determining unit 112, which receives an x-offset value from the system control unit and reflects only this value. In the present invention, the black dotted line shown in FIG. 6 is further added from the color matching pattern generator 200. The pattern number (PAT_NOn) information is input in real time at the time of generating the pattern and reflected in the x-offset to generate the line synchronization delayed by a value corresponding to the pattern number (PAT_NOn) compared to the conventional line synchronization. Of course, the phase of the video clock vclk is equally delayed.

The value corresponding to the pattern number PAT_NOn may be greater than or equal to a dot unit or may be repeated only in a sub-dot unit according to the configuration in which the color matching pattern generator 200 generates the black dotted line. For example, when repeating only in the sub-dot unit, if the pattern number (PAT_NOn) is increased by one, the x-offset value of the sub-dot unit to be additionally reflected in the x-offset is 0, 1/4, 2/4, 3/4. , 0, 1/4 .... In this way, the pattern is generated in increments of 1/4 dots, and the color matching pattern generator 200 generates a pattern in increments of one dot each time the pattern number (PAT_NOn) is increased by four. Let's do it.

At this time, by dividing a line into several unit blocks, the video clock frequency can be minutely changed for each block, so that middle lines of one line can match color in the scan direction.

The color matching pattern generator 200 of FIG. 4 receives a page sync from a system controller (not shown) and a line sync and a video clock from the video clock generator 100, such as the manual adjustment scan direction of FIG. 6. Generate a killar matching pattern. In addition, the information corresponding to the black dotted line pattern number PAT_NOn shown in FIG. 6 is transmitted to the video clock generator 100 in real time during pattern generation.

4 illustrates only a block k corresponding to a black color as an embodiment of the present invention, and blocks corresponding to the remaining colors are independently present. However, blocks for the remaining colors do not need to transmit the pattern number (PAT_NOn) information to the video clock generator 100.

FIG. 5 is a diagram illustrating a waveform and a phase relationship of line sync and video clock vclk based on horizontal sync (hsync) input from an LSU.

6 shows an example of the waveform at the time of generating the black dotted line pattern increasing in 0.5 dot units as in the example of FIG. 6. The line sync occurrence point based on the horizontal sync (hsync) is repeated by 0 dots → 0.5 dots → 0 dots → 0.5 dots at the time corresponding to the conventional x-offset of FIG. 2 according to the pattern number (PAT_NOn). Indicates.

Fig. 6 is a diagram showing an example of the color matching pattern output image of the present invention. In FIG. 6, color matching patterns for black and cyan colors are taken as an example. The black color is a dotted line pattern and the cyan color is a vertical line pattern. An example is a case where the black dotted line dotted pattern increases by 0.5 dots according to the pattern number PAT_NOn in the scanning direction. Cyan Color Finds the black dotted pattern number (PAT_NOn) that best matches the vertical line to match the relative scan direction color registration between black and cyan. In FIG. 6, the pattern number 4 (PAT_NO4) is the state that most closely matches the cyan vertical line pattern. Based on the pattern number 4 (PAT_NO4) determined above, the system controller sets the newly corrected x-offset value to the x-offset determiner 112 of the video clock generator 100.

The pattern with the black dotted line pattern and the yellow (or magenta) vertical line is omitted in FIG. 6, but the description will be omitted since it is apparent to those skilled in the art that the structure is the same as that of FIG. 6.

Although FIG. 6 illustrates an increase of 0.5 dots, the black dotted line pattern may be generated in increments of more precise subdots according to the x-offset reflection accuracy that may be processed by the video clock generator 100.

As described above, a tandem type color laser printer generally uses LSUs independently, one for each color, and misregistration between colors in the scanning direction due to the scan speed deviation for each LSU or the mechanism deviation for each color. Occurs. In the color matching pattern generating device applied to the color image forming apparatus of the present invention, after printing the pattern as shown in FIG. Since the scheme is applied, the spacing between adjacent black dotted lines of FIG. 6 may be finely implemented in sub-dot units to more accurately correct scan direction matching errors between colors.

1 is a block diagram illustrating a video clock generator and a color matching pattern generator.

2 is a waveform diagram illustrating a video clock (vclk) generated in a conventional line sync and video clock generator.

3 is a waveform diagram showing an example of a conventional color matching pattern.

4 is a block diagram illustrating a video clock generator and a color matching pattern generator of the present invention.

FIG. 5 is a waveform diagram showing video clock vclk generated in a line sync and video clock generator of the present invention. FIG.

Fig. 6 is a waveform diagram showing an example of the color registration pattern of the present invention.

<Explanation of symbols for the main parts of the drawings>

100 ... Video Clock Generator, 112 ... x-Offset Determinant

114 ... Video Clock Synthesizer, 200 ... Color Matching Pattern Generator

Claims (3)

A plurality of laser scan units (LSUs) for exposing a photosensitive medium to form a latent image; A plurality of photosensitive media forming a latent image in response to exposure of the LSU; And a plurality of developing units, one for each color for forming a toner image on the latent image formed on the photosensitive medium, the color matching pattern generating device of the color image forming apparatus comprising: It generates a line sync signal and a video clock synchronized with a horizontal sync signal from the LSU and reflecting an x-offset value in units of dots and subdots. And a plurality of video clock generators receiving information corresponding to the line position of the pattern in real time when generating the pattern from the color matching pattern generator, and additionally reflecting the x-offset value in sub-dot units; And Color matching of a color image forming apparatus including a plurality of color matching pattern generators generating a color matching pattern in a scan direction and transmitting information corresponding to a line position of a pattern currently generated in real time during pattern generation to the video clock generator Pattern generator. The method of claim 1, wherein the color matching pattern in the scan direction has a scan direction interval between dots of each individual pattern in the entire pattern as shown in the example of FIG. 6, or a dot or subdot interval. Color matching pattern generating device of the color image forming apparatus, characterized in that the pattern consisting of a unit interval. The apparatus of claim 1 or 2, wherein the information corresponding to the line position of the pattern is a pattern number PAT_NOn of each individual pattern as in the example of FIG. .