JP2020144197A - Image forming apparatus - Google Patents

Abstract

To make it possible, in performing correction for image formation, to accurately perform the correction even when a reference color in the correction is replaced with another color.SOLUTION: An image forming apparatus according to the present invention performs image formation on a recording medium by using multiple colors including a reference color, and comprises: a determination unit that determines a portion where image formation is performed with the reference color; a correction unit that performs correction with a pattern in the reference color formed in the portion determined by the determination unit as a reference; and an image forming unit that performs image formation based on a result of the correction performed by the correction unit.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image forming apparatus.

Conventionally, a so-called double-sided printing method is known in which an image is formed on both sides of a recording medium. Then, in double-sided printing, a method of correcting the deviation of images formed on both sides is known.

Specifically, in double-sided printing, first, the image forming apparatus marks the first mark on one of the surfaces (hereinafter referred to as "first surface") outside the area where the image formation is performed. Similarly, the image forming apparatus marks a surface different from the first surface (hereinafter, referred to as “second surface”) with the second mark corresponding to the first mark. Then, the image forming apparatus reads the first mark and the second mark. In this way, the image forming apparatus determines the deviation between the first mark and the second mark. Based on such a determination result, the image forming apparatus corrects the positions of the image forming regions on the first surface and the second surface. A method of improving the accuracy of correcting the deviation of the image forming region by such correction is known (see, for example, Patent Document 1).

However, in the conventional method, it is premised that the reference color forms an image at a fixed position. That is, it is not assumed that the reference color in the correction of the pattern used for the correction and the color forming the mark or the like is replaced with another color. Therefore, if the reference color in the correction becomes a different color, it may be difficult to perform the correction with high accuracy.

One aspect of the present invention is to make a correction for image formation with high accuracy even if the color used as a reference in the correction is replaced with another color.

According to one embodiment of the present invention
An image forming apparatus that forms an image on a recording medium using multiple colors including a reference color is
A judgment unit that determines where the reference color forms an image, and
A correction unit that performs correction based on the reference color pattern formed in an image at a location determined by the determination unit,
It is characterized by including an image forming unit that forms an image based on the result of correction by the correction unit.

According to the embodiment of the present invention, when the image formation is corrected, even if the reference color in the correction is replaced with another color, the correction can be performed with high accuracy.

It is the schematic which shows the hardware configuration example of the image forming apparatus. It is the schematic which shows the example of replacement. It is the schematic which shows the example of superposition. This is an example of pattern placement. It is an example of forming a mark and an example of detecting a mark. It is a figure which shows the correction example. It is a figure which shows the comparison example with the correction using a different color. It is a flowchart which shows the whole processing example. It is a functional block diagram which shows the functional structure example of an image forming apparatus. It is a schematic diagram which shows the comparative example.

Hereinafter, the optimum mode for carrying out the invention will be described with reference to the drawings.

For example, the image forming apparatus is an apparatus having the following hardware configuration.

<Hardware configuration example of image forming apparatus>
FIG. 1 is a schematic view showing a hardware configuration example of an image forming apparatus. For example, as shown in the figure, the image forming apparatus 100 includes a CPU (Central Processing Unit, hereinafter referred to as “CPU100H1”), an image forming unit 100H2, a writing unit 100H3, an intermediate transfer belt 100H4, a secondary transfer apparatus 100H5, and a fixing apparatus. It is a hardware configuration having 100H6, a pattern detection sensor 100H7, a mark detection sensor 100H8, and the like.

Hereinafter, the direction in which the recording medium is conveyed is referred to as "transportation direction Y".

The CPU 100H1 is an example of an arithmetic unit and a control unit. That is, the CPU 100H1 performs processing such as various determinations and corrections based on the data or the like that can be acquired by the sensor.

The image forming unit 100H2 is a photoconductor or the like. That is, the image forming unit 100H2 receives the laser beam emitted by the writing unit 100H3 to form a transferred image. After that, the image forming unit 100H2 adheres the toner to the portion to be the transferred image to form the toner image.

Further, as shown in the figure, the image forming unit 100H2 includes, for example, "Bk" (indicating an image forming unit for black), "C" (indicating an image forming unit for cyan), and "M" (magenta). It is installed for each color, such as "Y" (indicating an image-forming unit for yellow) and "S" (indicating an image-forming unit for spot colors). Hereinafter, five colors will be described as an example, but the image forming apparatus 100 may use multiple colors, and the types of colors and the number of colors are not limited to the configurations shown in the drawings.

The writing unit 100H3 is an optical device that irradiates the image forming unit 100H2 with a laser beam based on the input image data.

The toner image formed by the image forming unit is primarily transferred to the intermediate transfer belt 100H4. Then, the toner image first transferred to the intermediate transfer belt 100H4 is secondarily transferred to the paper by the secondary transfer device 100H5.

The secondary transfer device 100H5 secondarily transfers the toner image primary transferred to the intermediate transfer belt 100H4 onto the paper.

The fixing device 100H6 fixes the toner image secondarily transferred to the paper. Specifically, the fixing device 100H6 fixes by applying heat or the like.

The pattern detection sensor 100H7 is an optical sensor or the like that detects a toner pattern formed on the intermediate transfer belt 100H4 by the image forming unit 100H2. For example, the pattern detection sensor 100H7 detects superposition with multicolored toner and the like.

The mark detection sensor 100H8 detects a mark formed on the paper. The details of the processing based on the mark detection result by the mark and the mark detection sensor 100H8 will be described later.

The paper, which is an example of the recording medium, is first flowed through the input path F1 and an image is formed on the first surface of the paper. Then, image formation is also performed on the second surface, that is, in the case of double-sided printing, when image formation is completed on the first surface in the input path F1, the recording medium subsequently flows through the double-sided printing path F2. On the other hand, in the case where only the first side is the object of image formation, that is, in the case of single-sided printing, when the image formation is completed on the first side in the input path F1, the paper is discharged in the paper ejection path F3. On the other hand, in the case of double-sided printing, when the double-sided printing path F2 is passed, an image is formed on the second side, and when the image formation on the first side is completed, the paper is discharged from the paper discharge path F3. It will be discharged.

Hereinafter, the color forming the mark is referred to as a "reference color". The reference color is preferably a color having the highest contrast with respect to the color of the recording medium among the colors possessed by the image forming apparatus 100. Specifically, if the color of the recording medium is white, the reference color is preferably black (that is, it is desirable that a "Bk" toner is used). As described above, with the combination of colors having high contrast, the mark detection sensor 100H8 can accurately detect the position where the mark or the like is formed. Therefore, the accuracy of corrections and the like using the positions of marks and the like can be improved. The combination of the reference color and the color of the recording medium may be another combination. For example, if the color of the recording medium is black and the spot color is white, the reference color is preferably white, which is the spot color.

The spot color may be any color other than "Bk", "C", "M" and "Y". For example, the spot color may be fluorescent yellow, neon pink, or the like. Further, it is desirable that the spot color and the color of the recording medium have a complementary color relationship. In this way, the complementary color relationship can increase the contrast. Specifically, a combination may be used in which reading is performed in blue and a special color of fluorescent yellow is used for a bluish-purple recording medium.

Hereinafter, an example will be described in which the recording medium is white and the reference color is black.

Further, the image forming unit 100H2 and the like can be replaced by a user operation or the like. Specifically, the following replacements are possible.

FIG. 2 is a schematic view showing an example of replacement. Hereinafter, an example will be described in which "Bk" (black) and "S" (special color) are exchanged. The color to be replaced may be another color.

Further, in the following example, it is assumed that multiple colors are initially set in the arrangement as shown in FIG. Then, as shown in the figure, "S" and "Bk" are to be exchanged. Specifically, due to the replacement, in the arrangement after the replacement, the "S" is arranged at the position closest to the position where the secondary transfer is performed (in the figure, it is the rightmost position in the multicolor). On the other hand, due to the replacement, in the arrangement after the replacement, the "Bk" is arranged at the position farthest from the position where the secondary transfer is performed (in the figure, it is the leftmost position in the multicolor).

As shown below, in the initial setting, as shown in FIG. 1, an image is formed at the first station P1 (in this example, the position closest to the position where the secondary transfer is performed) with "Bk". Suppose that it is set as. Therefore, in this example, the images are formed by superimposing the respective colors in the order of the fifth station P5, the fourth station P4, the third station P3, the second station P2, and the first station P1. Specifically, the superposition is as follows.

FIG. 3 is a schematic view showing an example of superposition. FIG. 3A shows the result of superposition before replacement. On the other hand, FIG. 3B shows the result of superposition after the replacement.

As shown in the figure, before the replacement, "S", that is, the spot color is formed on the paper by the secondary transfer.

In this example, first, "Bk" was set in the first station P1 and "S" was set in the fifth station P5 before the replacement. After the replacement, the locations of "Bk" and "S" are swapped, so that "S" is set in the first station P1 and "Bk" is set in the fifth station P5.

In this way, if the toner can be replaced, the order of the toners transferred by the secondary transfer can be changed. Therefore, by changing the toner order, it is possible to increase the number of applications that can be printed.

Even if the colors are replaced, the position of the reference colors is constant as follows, regardless of the color replacement, when the superposition correction, which is an example of the first correction, is performed based on the reference colors. To.

FIG. 4 is an example of pattern arrangement. For example, as shown in the figure, in the correction, it is desirable that "Bk", which is an example of the reference color, is arranged in the middle of the five colors. With such an arrangement, the total distance between the positions where the reference color patterns are formed and the positions where the respective color patterns are formed becomes shorter. If the distance from the reference color is long, it may cause an error in correction or the like. Therefore, as shown in the figure, it is desirable that the colors are arranged so that the distance between each color is as short as possible with respect to the reference color. With such an arrangement, errors can be reduced in correction and the like.

Therefore, even if the replacement is performed, the image forming apparatus forms an image of the pattern used for the correction so that the arrangement as shown in the figure, that is, the reference color is arranged in the center and used as a reference.

FIG. 5 shows an example of mark formation and an example of mark detection. FIG. 5 (A) shows an example of the first surface, that is, the front surface of the paper PA, while FIG. 5 (B) shows an example of the second surface, that is, the back surface.

For example, the mark MK is preferably formed in the shape and position as shown. Specifically, it is desirable that the mark MK is image-formed at the four corners as shown in the figure. However, the mark MK does not have to be the number, shape and position as shown in the figure, but may be any number, shape and position that the sensor can recognize each mark.

The mark MK formed in this way is detected by the mark detection sensor 100H8 or the like. The mark detection sensor 100H8 outputs the position where each mark MK is formed as a detection result in the form of coordinates or the like.

The mark MK is not limited to the shape and arrangement as shown in the figure. That is, the mark MK may have other shapes and arrangements. However, the shape and arrangement as shown in the figure are suitable for correcting the position of image formation as shown below, for example.

FIG. 6 is a diagram showing a correction example. FIG. 6A shows the surface of the paper PA. On the other hand, FIG. 6B shows the back surface of the paper PA. Hereinafter, as shown in the figure, a case where the paper PA is distorted will be described as an example. In such a case, it is desirable that the second correction is performed so that the position where the image formation is performed on the first surface and the position where the image formation is performed on the second surface are aligned.

As shown in the figure, when the mark MK is formed on the surface, the position where the image is formed can be detected, such as the a point, the b point, the c point, and the d point, by detecting the mark MK.

Then, in the case of double-sided printing, that is, when image formation is performed on the second side, the paper PA is inverted from the shape shown in FIG. 6 (A) as shown in FIG. Shape.

As shown in FIG. 6A, when the position where the mark MK is formed can be detected, the image forming apparatus also forms an image on the second surface at a position aligned with the first surface, that is, on the first surface. The position at which the image is formed can be corrected so that the image is formed at a position where the position is inverted horizontally and vertically.

In this way, when performing a plurality of corrections, it is desirable that the reference color and the mark used for the correction are the same color. In this way, if each correction is performed with different colors without using the standard color in a unified manner, for example, the following phenomena are likely to occur.

FIG. 7 is a diagram showing a comparative example with correction using different colors. For example, a case where the mark MK is set to "Bk" for correcting the alignment as shown in FIG. 6 will be described as an example.

First, when the superposition correction as shown in FIG. 4 is performed and the correction is performed with reference to "Bk", an image is formed at a position as shown in the figure (hereinafter referred to as "black correction position CRB"). Will be done. On the other hand, when the correction is performed with reference to "S", the image is formed at a position as shown in the figure (hereinafter referred to as "comparative example position CRC").

Black correction position Like CRB, the color used as the reference in the superposition correction, which is an example of the first correction, and the color used to form the mark in the front and back alignment correction, which is an example of the second correction. If and are unified, the correction can be performed in the ideal state as shown in FIG.

On the other hand, if the color used as the reference in the superposition correction and the color used to form the mark in the front and back alignment correction are different, the superposition correction is performed from the ideal state to the superposition correction. There is an error in. Due to this error, as shown in the figure, an error ERR may occur between the black correction position CRB and the comparative example position CRC.

On the other hand, if black is used in a unified manner, such an error ERR can be reduced.

<Overall processing example>
FIG. 8 is a flowchart showing an example of overall processing. First, when the first correction is performed, the image forming apparatus proceeds to step S1.

In step S1, the image forming apparatus determines whether or not the colors have been replaced. That is, the image forming apparatus determines the place where the reference color forms an image.

For example, the location where the reference color forms an image is determined by the user's settings and the like. Therefore, when the replacement as shown in FIG. 2 is performed, the user sets that the portion where the image is formed by the reference color is replaced with "S" by the replacement at the time of replacement. For example, the image forming apparatus makes a judgment based on such a setting.

Next, for example, when the replacement is performed as shown in FIG. 2 and the locations where the reference colors perform image formation are replaced (YES in step S1), the image forming apparatus proceeds to step S2. On the other hand, if the reference color does not change the position where the image is formed (NO in step S1), the image forming apparatus proceeds to step S3.

In step S2, the image forming apparatus performs the first correction by the reference color that forms an image at the place after the replacement. Specifically, when there is a replacement as shown in FIG. 2, "Bk" forms an image at the fifth station P5. Therefore, the image forming apparatus corrects the superposition based on the pattern formed in the image at the fifth station P5.

In step S3, the image forming apparatus performs the first correction by the reference color that forms an image at the place before the replacement. Specifically, "Bk" forms an image at the first station P1. Therefore, the image forming apparatus corrects the superposition or the like with reference to the pattern formed by the image at the first station P1.

As described above, in both step S2 and step S3, the image forming apparatus superimposes the pattern arrangement as shown in FIG. 4, that is, based on "Bk" which is an example of the reference color. Is corrected.

Subsequently, the image forming apparatus preferably performs step S4.

In step S4, the image forming apparatus performs the second correction with the same reference color as the first correction. Specifically, as shown in FIG. 6, the image forming apparatus forms a mark in the second correction with "Bk" used to form a reference pattern in the first correction. In this way, if a plurality of corrections are performed using the unified color, the correction can be performed with high accuracy.

<Function configuration example>
FIG. 9 is a functional block diagram showing a functional configuration example of the image forming apparatus. For example, the image forming apparatus 100 has a functional configuration including a determination unit FN1, a first correction unit FN2, and an image forming unit FN4. Further, as shown in the figure, it is desirable that the image forming apparatus 100 has a functional configuration further including a second correction unit FN3. Hereinafter, the illustrated functional configuration will be described as an example.

The determination unit FN1 performs a determination procedure for determining a portion where the reference color forms an image. For example, the determination unit FN1 is realized by the CPU 100H1 or the like.

The first correction unit FN2 performs the first correction procedure of performing correction based on the pattern of the reference color formed in the image at the portion determined by the determination unit FN1. For example, the first correction unit FN2 is realized by the CPU 100H1 or the like.

The second correction unit FN3 performs a second correction procedure of correcting so that the position where the image is formed on the second surface is aligned with the first surface based on the mark of the reference color for forming the image on the first surface. For example, the second correction unit FN3 is realized by the CPU 100H1 or the like.

The image forming unit FN4 performs an image forming procedure for forming an image based on the result of correction by the first correction unit FN2 and the second correction unit FN3. For example, the image forming unit FN4 is realized by an image forming unit 100H2 or the like.

As shown in the figure, the determination unit FN1 determines a portion where the reference color forms an image based on the setting by the user (hereinafter, the data indicating the setting value or the like input in the setting is referred to as "setting data D1"). .. Such setting data D1 is stored in a storage device such as a memory, for example.

The determination unit FN1 is not limited to determining based on the setting data D1. For example, the determination unit FN1 may detect a portion where the reference color forms an image.

Further, as shown in the figure, it is desirable to use data indicating the size, thickness, gloss, color of the recording medium, or a combination thereof (hereinafter referred to as "recording medium data D2") for the recording medium. In this way, when the recording medium data D2 is input, the image forming apparatus 100 can grasp the color and the like of the recording medium. Therefore, the image forming apparatus 100 can select a color having the highest contrast.

Further, the shape or size of the recording medium in an ideal state as shown in FIG. 5 may be input to the recording medium data D2. Then, the first correction or the like may be performed so as to correct to this ideal state.

As described above, even if black, which is an example of the reference color, is replaced with another color, correction is performed using black in a unified manner, such as correction based on black or forming a mark with black. In this way, when the image formation is corrected, even if the color used as the reference in the correction is replaced with another color, the correction can be performed with high accuracy.

<Comparison example>
FIG. 10 is a schematic view showing a comparative example. For example, as in the above example, a case where "S" and "Bk" are exchanged in a comparative example will be described as an example.

In the comparative example, the correction or the like is performed with "S". Therefore, in the comparative example, the correction may not be possible with the arrangement of the pattern as shown in FIG. Alternatively, the pattern formed by "S" may not be corrected.

<Other Embodiments>
The recording medium is not limited to paper or the like. That is, the recording medium may be made of a material to which toner or the like can adhere. For example, the material to which toner or the like can adhere is paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics or a combination thereof, and the material to which toner or the like adheres even temporarily. Just do it.

Further, the image forming apparatus may have a hardware configuration further including an apparatus other than the above. For example, the devices such as the control device and the arithmetic device may be a plurality of devices.

All or part of each process according to the present invention may be described in a low-level language or a high-level language, and may be realized by a program for causing a computer to execute an image forming method. That is, the program is a computer program for causing a computer such as an image forming apparatus or an image forming system to execute each process.

Therefore, when the image forming method is executed based on the program, the arithmetic unit and the control device of the computer perform the arithmetic and control based on the program in order to execute each process. In addition, the storage device of the computer stores the data used for the processing based on the program in order to execute each processing.

The program can also be recorded and distributed on a computer-readable storage medium. The storage medium is a medium such as a magnetic tape, a flash memory, an optical disk, a magneto-optical disk, or a magnetic disk. In addition, the program can be distributed over telecommunication lines.

The embodiment of the present invention may be realized by an image forming system. Further, the image forming system may execute each process as redundant, distributed, parallel, virtualized, or a combination thereof.

Although an example in the embodiment has been described above, the present invention is not limited to the above embodiment. That is, various modifications and improvements are possible within the scope of the present invention.

100 image forming apparatus 100H1 CPU
100H2 Image drawing unit 100H3 Writing unit 100H4 Intermediate transfer belt 100H5 Secondary transfer device 100H6 Fixing device 100H7 Pattern detection sensor 100H8 Mark detection sensor CRB Black correction position CRC Comparative example Position D1 Setting data D2 Recording medium data ERR Error F1 Input path F2 Both sides Printing route F3 Paper ejection route FN1 Judgment unit FN2 1st correction unit FN3 2nd correction unit FN4 Image forming unit MK mark P1 1st station P2 2nd station P3 3rd station P4 4th station P5 5th station PA Paper Y Conveyance direction

JP-A-2017-167306

Claims (5)

An image forming apparatus that forms an image on a recording medium using multiple colors including a reference color.
A judgment unit that determines where the reference color forms an image, and
A correction unit that performs correction based on the reference color pattern formed in an image at a location determined by the determination unit,
An image forming apparatus including an image forming unit that forms an image based on the result of correction by the correction unit. The image forming apparatus according to claim 1, wherein the reference color is a color having the highest contrast with respect to the color of the recording medium among the multiple colors. The image forming apparatus according to claim 2, wherein the reference color is black and the recording medium is white. The correction unit
Based on the pattern, the first correction that corrects the superposition of the multicolors and
Any one of claims 1 to 3 that performs a second correction that corrects the position where the image is formed on the second surface so as to be aligned with the first surface based on the mark of the reference color that forms the image on the first surface. The image forming apparatus according to item 1. The image forming apparatus according to any one of claims 1 to 4, wherein the place where the image is formed can be exchanged for the multicolor.

Images