JP2021193783A - Image correction device, image forming apparatus, image correction method, and program - Google Patents

Abstract

To automatically correct an image forming position of preliminary printing image data or additional printing image data.SOLUTION: An image correction device comprises: correct answer information acquisition means (correct answer information acquisition unit 51) that acquires correct answer information including composite image data of a plurality of pieces of image data, position information on a boundary part, and image distinction area information; alignment means (alignment unit 52) that aligns the composite image data and read image data obtained by reading an inspection image with each other; boundary part detection means (positional deviation correction unit 53) that detects an inspection boundary part from the read image data; calculation means (positional deviation correction unit 53) that compares pixel values between the boundary part and the inspection boundary part in an aligned state and calculates the amount of positional deviation; determination means (positional deviation correction unit 53) that determines the type of positional deviation based on the amount of positional deviation and the image distinction area information; and correction means (positional deviation correction unit 53) that corrects an image forming position of at least one piece of image data of the plurality of pieces of image data.SELECTED DRAWING: Figure 2

Description

The present invention relates to an image correction device, an image forming device, an image correction method and a program.

Conventionally, in decorative (processing) printing that adds value to printed matter, there is a process of printing a decorative portion and a non-decorative portion at different timings. In the final printed matter, which is a printed matter obtained by synthesizing the decorated portion and the non-decorated portion, it is desired that there is no positional deviation in terms of quality when the decorated portion and the non-decorated portion are printed adjacent to each other.

As an image inspection technique for the reprint printing result in the case of performing reprint printing to print the decorative portion, for example, in Patent Document 1, an image to be inspected is generated by reducing the influence of the preprinted image data on the inspection. , Inspecting reprinted print images is described.

Japanese Unexamined Patent Publication No. 2011-70548

The technique described in Patent Document 1 is an inspection on a reprinted image on a recording medium, and when a misalignment between two types of images, a preprinted image data and a reprinted image data on the recording medium, is detected. Position correction could not be performed automatically, and the user had to make adjustments to adjust the misalignment of the final printed matter.

An object of the present invention is to automatically correct a misalignment between an image of pre-printed image data on a recording medium and post-printed image data.

In order to solve the above problems, the image correction device of the invention according to claim 1 is used.
It is an image correction device that corrects the positional deviation between individual images in an inspection image obtained by forming individual images based on a plurality of image data on the same recording medium at different timings and synthesizing them.
A correct answer information acquisition means for acquiring correct answer information including composite image data of a plurality of image data, position information of a boundary portion of adjacent individual images, and image distinction area information capable of distinguishing the plurality of image data.
An alignment means for aligning the composite image data and the read image data obtained by reading the inspection image formed on the recording medium, and
A boundary portion detecting means for detecting an inspection boundary portion based on the position information of the boundary portion from the read image data, and a boundary portion detecting means.
A calculation means for calculating the amount of misalignment between individual images in the inspection image by comparing the pixel values of the boundary portion of the composite image data and the inspection boundary portion of the read image data in the aligned state. When,
A determination means for determining the position shift type based on the position shift amount and the image distinction area information, and
A correction means for correcting the image formation position of at least one of the plurality of image data according to the amount of misalignment and the type of misalignment.
To prepare for.

The invention according to claim 2 is the invention according to claim 1.
The position information of the boundary portion includes edge information of the plurality of image data.

The invention according to claim 3 is the invention according to claim 1 or 2.
The correct answer information includes directional information indicating the directionality of the boundary portion.
The calculation means determines the direction of misalignment based on the direction information.

The invention according to claim 4 is the invention according to any one of claims 1 to 3.
The calculation means calculates the overall average vertical displacement amount and average lateral displacement amount on the recording medium from the vertical and horizontal positional deviation amounts of each inspection boundary portion on the recording medium.

The invention according to claim 5 is the invention according to claim 4.
The calculation means calculates a vertical shift correction value and a horizontal shift correction value based on the overall average vertical deviation amount and average lateral deviation amount on the recording medium.

The invention according to claim 6 is the invention according to any one of claims 1 to 4.
The calculation means divides the in-plane on the recording medium into a plurality of regions (N ≧ 2), and from the amount of vertical and horizontal misalignment of the inspection boundary portion existing in each region, each region. Calculate the average vertical deviation amount and the average lateral deviation amount.

The invention according to claim 7 is the invention according to claim 6.
The calculation means calculates the average vertical deviation amount in one or more regions existing in the upper part and the lower part from the vertical center position of the divided recording medium, and corrects the vertical shift from the average vertical deviation amount of each part. The value is calculated, the average lateral displacement amount in one or more regions existing in the left portion and the right portion respectively from the lateral center position of the divided recording medium is calculated, and the lateral shift correction is performed from the average lateral displacement amount of each portion. Calculate the value.

The invention according to claim 8 is the invention according to claim 7.
The vertical double correction value is calculated from the average vertical shift amount of each part after the vertical shift correction or the horizontal shift correction, and the horizontal double correction value is calculated from the average horizontal shift amount of each part.

The invention according to claim 9 is the invention according to any one of claims 1 to 8.
The calculation means divides the in-plane on the recording medium into a plurality of regions (M ≧ 4), and from the amount of vertical and horizontal misalignment of the inspection boundary portion existing in each region, each region. Calculate the average vertical deviation amount and average lateral deviation amount of
The determination means determines the type of positional deviation according to the average vertical displacement amount and the average lateral displacement amount for each region.

The invention according to claim 10 is the invention according to claim 9.
The calculation means is the average position deviation in the same direction calculated in the portions located in the crossing relationship when the upper left portion, the upper right portion, the lower left portion and the lower right portion are set with reference to the center position of the recording medium in the region. A tilt correction value or a rotation correction value is calculated based on the amount.

The invention according to claim 11 is the invention according to any one of claims 1 to 10.
A setting means for setting the misalignment amount to be corrected is provided.

The image forming apparatus of the invention according to claim 12 is
The image correction device according to any one of claims 1 to 11.
It is provided with an image forming unit for forming an image on paper.

The image correction method of the invention according to claim 13 is
This is an image correction method for correcting the positional deviation between individual images in an inspection image obtained by forming individual images based on a plurality of image data on the same recording medium at different timings and synthesizing them.
A correct answer information acquisition step for acquiring correct answer information including composite image data of a plurality of image data, position information of a boundary portion of adjacent individual images, and image distinction area information capable of distinguishing the plurality of image data.
An alignment step for aligning the composite image data and the read image data obtained by reading the inspection image formed on the recording medium, and
A boundary portion detection step for detecting an inspection boundary portion based on the position information of the boundary portion from the read image data, and a boundary portion detection step.
A calculation step of calculating the amount of misalignment between individual images in the inspection image by comparing the pixel values of the boundary portion of the composite image data and the inspection boundary portion of the read image data in the aligned state. When,
A determination step for determining the position shift type based on the position shift amount and the image distinction area information, and
A correction step for correcting the image formation position of at least one of the plurality of image data according to the position shift amount and the position shift type, and
including.

The program of the invention according to claim 14
A computer of an image correction device that corrects the positional deviation between individual images in an inspection image obtained by forming individual images based on a plurality of image data on the same recording medium at different timings and synthesizing them.
Correct answer information acquisition means for acquiring correct answer information including composite image data of a plurality of image data, position information of a boundary portion of adjacent individual images, and image distinction area information capable of distinguishing the plurality of image data.
An alignment means for aligning the composite image data and the scanned image data obtained by reading the inspection image formed on the recording medium.
A boundary portion detecting means for detecting an inspection boundary portion from the read image data based on the position information of the boundary portion.
A calculation means for calculating the amount of misalignment between individual images in the inspection image by comparing the pixel values of the boundary portion of the composite image data and the inspection boundary portion of the read image data in the aligned state. ,
Judgment means for determining the type of misalignment based on the amount of misalignment and the image distinction area information,
A correction means for correcting the image formation position of at least one of the plurality of image data according to the amount of misalignment and the type of misalignment.
To function as.

According to the present invention, it is possible to automatically correct the positional deviation between the preprinted image data on the recording medium and the reprinted printed image data.

It is a schematic sectional drawing which shows the whole structure of the image forming apparatus in embodiment of this invention. It is a block diagram which shows the functional structure of an image forming apparatus. It is a flowchart which shows the image correction process executed by an image forming apparatus. It is a figure which shows the composite image data, the boundary part position information, and the image distinction area information. It is a figure which shows the direction information in the boundary part position information. It is a figure which shows the case where the feature point used for alignment is an edge. It is a figure which shows the case where the feature point used for alignment is a marker. It is a figure which shows the pixel value comparison in a window. It is a figure which shows the continuity of the misalignment candidate coordinates, and the amount of misalignment. It is a figure which shows the example which the vertical double shift occurred. It is a figure which shows the example which the rotation deviation occurred.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

[Structure of image forming apparatus]
FIG. 1 is a schematic cross-sectional view showing the overall configuration of the image forming apparatus 100. FIG. 2 is a block diagram showing a functional configuration of the image forming apparatus 100. The image forming apparatus 100 forms an image composed of a plurality of colors on a recording medium.
The recording medium is not particularly limited, and a known recording medium can be used. For example, in addition to paper such as plain paper and coated paper, various media such as sheet-shaped resin capable of fixing a coloring material adhering to the surface can be mentioned.

As shown in FIG. 2, the image forming apparatus 100 includes a control unit 11, a storage unit 12, an operation unit 13, a display unit 14, a communication unit 15, an image generation unit 16, a scanner unit 17, an image memory 18, and an image processing unit 19. , An image forming unit 20, an image reading unit 30, a cutting unit 40, a correction unit 50, and the like are provided.

The control unit 11 includes a CPU (Central Processing Unit) and a RAM (Random Access Memory).
) And the like, and each unit is controlled by reading and executing various programs from the storage unit 12.
For example, the control unit 11 causes the image processing unit 19 to process the image data generated by the image generation unit 16 or the scanner unit 17 and held in the image memory 18, based on the image data after the image processing. The image forming unit 20 forms an image on the recording medium.

The storage unit 12 stores a program that can be read by the control unit 11, data used when the program is executed, and the like. As the storage unit 12, a large-capacity memory such as a hard disk can be used.

As shown in FIG. 1, the operation unit 13 and the display unit 14 are user interfaces provided on the upper part of the image forming apparatus 100.
The operation unit 13 generates an operation signal according to the user's operation and outputs it to the control unit 11. As the operation unit 13, a keypad, a touch panel integrally configured with the display unit 14, and the like can be used.
The operation unit 13 is used when setting a threshold value of the amount of misalignment used for determining the occurrence of misalignment. That is, the operation unit 13 functions as a setting means.
The display unit 14 displays an operation screen or the like according to the instructions of the control unit 11. As the display unit 14, an LCD (Liquid Crystal Display), an OLED (Organic Electro Luminescence Display), or the like can be used.

The communication unit 15 transmits / receives data to / from an external device connected to the communication network. For example, the communication unit 15 receives data (PDL data) in which the instruction content for forming an image is described in a page description language (PDL) from an external device.

The image generation unit 16 rasterizes the PDL data received by the communication unit 15 and generates image data in bitmap format. This image data is composed of four colors of C (cyan), M (magenta), Y (yellow) and K (black), and each pixel has a pixel value of four colors. The pixel value is a data value representing a shade of an image, and for example, an 8-bit data value represents a shade of 0 to 255 gradations.

The scanner unit 17 reads the original surface and generates image data in bitmap format having pixel values of each of R (red), G (green), and B (blue). This image data may be converted into image data of each of the four colors of CMYK by a color conversion unit or the like.

The image memory 18 is a buffer memory that temporarily holds the image data generated by the image generation unit 16 or the scanner unit 17. As the image memory 18, a DRAM (Dynamic RAM) or the like can be used.

The image processing unit 19 reads image data from the image memory 18 and performs various image processing such as density correction processing, color correction processing, and halftone processing.

The image forming unit 20 forms an image composed of four colors of CMYK on the recording medium according to the pixel values of the four colors of each pixel of the image data image-processed by the image processing unit 19.
As shown in FIG. 1, the image forming unit 20 includes four writing units 21, an intermediate transfer belt 22, a secondary transfer roller 23, a fixing device 24, a paper feed tray 25, and an inversion path 26.

The four writing units 21 are arranged in series (tandem) along the belt surface of the intermediate transfer belt 22 to form an image of each color of CMYK on the intermediate transfer belt 22. Each writing unit 21 has the same configuration except that the color of the image to be formed is different, and as shown in FIG. 1, the exposed unit 2a, the photoconductor 2b, the developing unit 2c, the charging unit 2d, the cleaning unit 2e, and the primary unit 21 are used. A transfer roller 2f is provided.

At the time of image formation, in each writing unit 21, after charging the photoconductor 2b by the charging unit 2d, the light beam emitted by the exposed unit 2a scans the photoconductor 2b based on the image data to form an electrostatic latent image. do. When a color material such as toner is supplied by the developing unit 2c for development, an image is formed on the photoconductor 2b.
The images formed on the photoconductors 2b of the four writing units 21 are sequentially superimposed and transferred (primary transfer) on the intermediate transfer belt 22 by the respective primary transfer rollers 2f. As a result, an image composed of each color is formed on the intermediate transfer belt 22. After the primary transfer, the cleaning unit 2e removes the coloring material remaining on the photoconductor 2b.

The image forming unit 20 supplies a recording medium from the paper feed tray 25, transfers an image from the intermediate transfer belt 22 onto the recording medium (secondary transfer) by the secondary transfer roller 23, and then transfers the recording medium to the recording medium by the fixing device 24. It is heated and pressurized to perform fixing treatment.
When an image is formed on both sides of the recording medium, the recording medium is conveyed to the inversion path 26, the front and back sides of the recording medium are inverted, and then the recording medium is conveyed to the secondary transfer roller 23 again.

As shown in FIG. 1, the image reading unit 30 is arranged on the transport path of the recording medium, and the image forming unit 20 reads the recording medium on which the image is formed and generates the scanned image data. As the image reading unit 30, a line sensor in which a sensor such as a CCD (Charge Coupled Device) is arranged one-dimensionally, an area sensor or the like arranged in two dimensions can be used.

When the cutting process is set, the cutting unit 40 cuts the peripheral portion of the conveyed recording medium at a preset position. The cutting unit 40 may cut the recording media one by one, or may cut a plurality of recording media together.

As shown in FIG. 2, the correction unit 50 includes a correct answer information acquisition unit 51, an alignment unit 52, a misalignment correction unit 53, and the like.
The processing content of each part of the correction unit 50 can be realized by hardware processing using an image processing circuit such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field-Programmable Gate Array), or can be realized by a CPU or GPU (Graphics). It can also be realized by software processing such as Processing Unit) that reads and executes the program.

The correct answer information acquisition unit 51 acquires the correct answer information stored in the storage unit 12 when the image correction process described later is executed. When the correct answer information is stored outside, the correct answer information acquisition unit 51 acquires the correct answer information from the outside via the communication unit 15.
That is, the correct answer information acquisition unit 51 functions as a correct answer information acquisition means.

The alignment unit 52 aligns the inspection image of the scanned image data acquired by the image reading unit 30 reading the final printed matter with the composite image of the composite image data.
Specifically, the alignment unit 52 extracts edge coordinate positions or marker coordinate positions, which are feature points existing in each image data, from the composite image data and the read image data, and aligns the feature points with each other. ..
The edge coordinate position is extracted by scanning on the composite image data and the read image data.
The marker coordinate position is prepared in advance so that the alignment marker is printed at the same position on the composite image data and the recording medium, and is extracted by scanning on the composite image data and the read image data. ..
That is, the alignment unit 52 functions as an alignment means.

The misalignment correction unit 53 determines the occurrence of misalignment from the comparison between the read image data and the composite image data.
Specifically, the misalignment correction unit 53 detects the inspection boundary portion on the inspection image based on the boundary portion position information. That is, the misalignment correction unit 53 functions as a boundary portion detecting means.
Next, the position shift correction unit 53 develops a window containing boundary portion position information on the composite image data and the read image data with the same size and the same phase coordinates as the base point.
Next, the position shift correction unit 53 compares the boundary portion of the composite image data and the inspection boundary portion of the read image data in the window, and there is a difference in the comparison result of the pixel values on the boundary portion position information. Stores the coordinate position in the storage unit 12 as a candidate for the occurrence of misalignment.
Next, the misalignment correction unit 53 evaluates whether the coordinate positions of the misalignment occurrence candidates have continuity based on the boundary portion position information.
Next, the misalignment correction unit 53 calculates the misalignment amount in the direction perpendicular to the direction information of the boundary portion position information, and determines the direction of the misalignment amount based on the direction information.
Next, the misalignment correction unit 53 calculates the average value of the misalignment amount on the entire surface of the recording medium for each direction, and performs vertical or horizontal shift correction based on the average misalignment amount for each direction and the image distinction area information. conduct.
Next, the misalignment correction unit 53 divides the in-plane on the recording medium into a plurality of regions (N ≧ 2), calculates the average value of the misalignment amount in each region for each direction, and calculates each region. The vertical or horizontal double correction is performed based on the average position shift amount for each direction and the image distinction area information.
Next, the misalignment correction unit 53 divides the in-plane on the recording medium into a plurality of regions (M ≧ 4), calculates the average value of the misalignment amount in each region for each direction, and calculates each region. The type of misalignment is determined based on the average amount of misalignment in each direction and the image distinction area information. The types of misalignment include tilt and rotation.
Next, the misalignment correction unit 53 corrects at least one of the pre-printed image data and the follow-up print image data based on the average misalignment amount and the misalignment type for each direction of each region.
That is, the misalignment correction unit 53 functions as a calculation means, a determination means, and a correction means.

The control unit 11, the storage unit 12, and the correction unit 50 realize the function as the image correction device 1000.

After the image is formed, the recording medium is discharged to the output tray T1 or the output tray T2 shown in FIG.

(Operation of image forming apparatus 1)
Next, the operation of this embodiment will be described.
FIG. 3 shows a flowchart of the image correction process executed by the image forming apparatus 1. The image correction process is executed in collaboration with the program stored in the control unit 11 and the storage unit 12.

First, the control unit 11 receives the pre-printed image data and the reprint print image data designated in association with each other via the communication unit 15 (step S1).
Next, the control unit 11 synthesizes the pre-printed image data and the reprint print image data to create the composite image data. Then, the control unit 11 stores the composite image data in the storage unit 12 (step S2). The control unit 11 may receive the composite image data created in advance from the outside via the communication unit 15.
Here, the upper left figure of FIG. 4 is an example of pre-printed image data, and the upper right figure is an example of reprinted print image data. The composite image data shown in the lower left figure is created from the data from now on.

Next, the control unit 11 extracts the edge information in the pre-printed image data and the reprint print image data. The control unit 11 may extract the edge information based on the vector data embedded in each image data. Further, the control unit 11 may perform edge determination by scanning each RIP image data with a small window for extraction, or may output each image data to be combined in advance and output an image reading unit. Extraction may be performed by performing edge determination by scanning the image area read in No. 30.
The control unit 11 stores edge information adjacent to the image data to be combined as a boundary portion, and stores the coordinate position of the boundary portion on the composite image data in the storage unit 12 as the boundary portion position information (step S3).
Here, the lower center figure of FIG. 4 is the boundary portion position information which is the coordinate position on the composite image data of the boundary portion.

Next, the control unit 11 creates image distinction area information capable of distinguishing each image data area from the pre-printed image data and the reprint print image data, and stores the image distinction area information in the storage unit 12 (step S4).
Here, the image distinction area information is shown in the lower right of FIG.

Next, the control unit 11 determines the directionality of the boundary portion from the angle of the boundary portion based on the boundary portion position information, and stores the direction information in the storage unit 12 (step S5).
Here, FIG. 5 is an example of direction information. For example, the control unit 11 determines that the directionality of the boundary portion parallel to the x-axis shown in the lower right of FIG. 5 is the horizontal direction, and the directionality of the other boundary portions is the vertical direction.
The threshold value for determining the horizontal direction and the vertical direction is set in advance, and the threshold value is not limited to this example. For example, a range from an angle parallel to the x-axis to a predetermined angle may be determined as the lateral direction.

The control unit 11 controls the image forming unit 20 to perform pre-printing on the recording medium (step S6).
Next, the control unit 11 controls the image forming unit 20 to start additional printing on the printed matter preprinted in step S6 (step S7).
Next, the control unit 11 uses the image reading unit 30 to perform additional printing to read the final printed matter on which the inspection image is formed, and acquires the scanned image data (step S8).

The alignment unit 52 aligns the inspection image of the read image data acquired in step S8 with the composite image of the composite image data acquired by the correct answer information acquisition unit 51 (step S9). FIG. 6 shows examples of edge coordinate positions and marker coordinate positions, which are feature points used for alignment.
FIG. 6A is a case where the edge coordinate position is used as the feature point, and FIG. 6B is a case where the marker coordinate position is used as the feature point.
In addition, position correction by shift or scaling to match the feature points of the composite image data and the scanned image data is performed on the composite image data side.

The position shift correction unit 53 detects the inspection boundary portion where the boundary portion on the inspection image is located based on the boundary portion position information acquired by the correct answer information acquisition unit 51 (step S10).
Next, the misalignment correction unit 53 expands an m × n (m ≧ 1, n ≧ 1) window containing the boundary portion position information on the composite image data and the read image data with the same size and the same phase coordinates as the base point. (Step S11).
FIG. 7 is an expanded view of a 4 × 4 window.

Next, the position shift correction unit 53 unifies the color space between the composite image data and the scanned image data, and compares the pixel values on the boundary portion position information between the composite image data and the scanned image data in the window.
In FIG. 7, there are places where the pixel values are different between the left window, which is the window on the composite image data, and the right window, which is the window on the scanned image data.
When the difference in the comparison result of the pixel values is equal to or greater than a predetermined threshold value, the misalignment correction unit 53 determines that the candidate is a candidate for misalignment, and stores the coordinate position of the candidate location for misalignment in the storage unit 12 (. Step S12).
The misalignment correction unit 53 carries out step S12 for all inspection boundary portions.

Next, the misalignment correction unit 53 evaluates whether or not the coordinate positions of the misalignment occurrence candidates have continuity based on the boundary portion position information (step S13).
FIG. 8 is a diagram in which a position shift occurrence candidate location exists along the boundary portion. There are candidate locations for misalignment along the portion indicated by the black dashed arrow in FIG. In this case, the misalignment correction unit 53 determines that the coordinate positions of the misalignment occurrence candidates have continuity based on the boundary portion position information.

Next, the misalignment correction unit 53 calculates the amount of misalignment of the position misalignment candidate location determined to have continuity in step S13, and determines the direction of the misalignment (step S14).
The method of calculating the misalignment amount is to obtain the continuous length of the candidate coordinate positions where the misalignment occurs in the direction perpendicular to the direction information acquired by the correct answer information acquisition unit 51, and use this as the misalignment amount.
The direction of misalignment is determined based on the direction information.
In FIG. 8, since the direction of the boundary portion where the white arrow is described is the vertical direction, the continuous length of the coordinate positions of the candidate for misalignment is obtained in the direction perpendicular to the vertical direction, that is, in the horizontal direction. , The length is defined as the amount of misalignment. The length is indicated by the length of the white arrow.
Further, regarding the direction of the positional deviation, since the direction of the boundary portion is the vertical direction, it is determined to be the direction perpendicular to it, that is, the horizontal direction.

Next, the misalignment correction unit 53 calculates the average value of the misalignment amount on the entire surface of the recording medium for each direction, and performs vertical or horizontal shift correction based on the average misalignment amount for each direction and the image distinction area information. (Step S15).
Specifically, the average vertical misalignment amount is calculated from the vertical misalignment amount of the entire surface of the recording medium, and the average lateral misalignment amount is calculated from the horizontal misalignment amount. From the calculated average vertical shift amount and average horizontal shift amount and the image distinction area information, the overall shift position shift amount of the additional print image data with respect to the pre-printed image data is determined, and the vertical shift correction or the horizontal shift correction is added. Perform for print image data.
For example, in FIG. 8, since the position shift in the lateral direction occurs on the entire surface of the recording medium, the lateral shift correction is performed.

Next, the misalignment correction unit 53 divides the in-plane on the recording medium into N-divided (N ≧ 2) regions (step S16).
Next, the misalignment correction unit 53 calculates the average amount of misalignment in each direction from the center of the vertical direction to the upper part, the lower part, and the center of the horizontal direction to the left part and the right part with respect to the recording medium surface. Vertical double correction or horizontal double correction is performed based on the average position shift amount for each direction and the image distinction area information (step S17).
Specifically, when the vertical double misalignment as shown in FIG. 9 occurs, the misalignment correction unit 53 calculates the average vertical misalignment amount in the upper part and the lower part. When it is determined that the difference in the average vertical deviation amount generated in the upper part and the lower part is equal to or more than a predetermined threshold value, the misalignment correction unit 53 reprints the image of the print image data with respect to the preprinted image data. It is judged that a vertical double deviation has occurred at the time of formation. The misalignment correction unit 53 calculates the amount of vertical misalignment of the reprint print image data with respect to the pre-printed image data from the difference in the average vertical misalignment amount between the upper part and the lower part and the image distinction area information. The position shift correction unit 53 performs vertical double correction for the calculated vertical double position shift amount on the additional printing image data. Further, the position shift correction unit 53 calculates the average lateral displacement amount of the left portion and the right portion. In this case, since the lateral doubling deviation does not occur, the calculated average lateral displacement amount is less than a predetermined threshold value, and the lateral doubling correction is not performed.
Further, when the vertical double shift does not occur and the horizontal double shift occurs, the position shift correction unit 53 calculates the average lateral shift amount in the left portion and the right portion. When it is determined that the difference in the average lateral displacement amount generated in the left portion and the right portion is equal to or larger than a predetermined threshold value, the misalignment correction unit 53 transfers the image of the additional print image data to the preprinted image data. It is judged that a lateral double deviation has occurred at the time of formation. The misalignment correction unit 53 calculates a laterally doubled misalignment amount of the reprint print image data with respect to the preprinted image data from the difference in the average lateral misalignment amount between the left portion and the right portion and the image distinction area information. The misalignment correction unit 53 performs horizontal double correction for the calculated horizontal double misalignment amount for the additional printing image data. Further, the position shift correction unit 53 calculates the average vertical shift amount of the upper part and the lower part. In this case, since the vertical double shift does not occur, the calculated average vertical shift amount is less than a predetermined threshold value, and the vertical double correction is not performed.

Next, the misalignment correction unit 53 divides the in-plane on the recording medium into M division (M ≧ 4) regions (step S18).
Next, the misalignment correction unit 53 calculates the average misalignment amount for each direction in each of the upper left portion, the lower left portion, the upper right portion, and the lower right portion from the center of the recording medium surface (step S19).
Then, the position shift correction unit 53 determines the position shift type of rotation or inclination from the calculated average position shift amount for each direction in each section and the image distinction area information (step S20), and corrects according to the judgment result. This is performed (step S21), and the process is terminated.
Specifically, when the rotation deviation as shown in FIG. 10 occurs, the position deviation correction unit 53 calculates the average position deviation amount for each direction in each unit. The average vertical displacement amount and the average lateral displacement amount occurring in the intersecting part such as the upper left and the lower right, and the upper right part and the lower left are the positional deviations in the opposite direction, and the same direction calculated in all the parts. When the difference between the absolute values of the average misalignment amount is equal to or less than a predetermined threshold value, the misalignment correction unit 53 determines that the rotation misalignment has occurred. At this time, the misalignment correction unit 53 performs rotation correction on the reprinted print image data in order to match the reprinted print image data with the preprinted image data.
In FIG. 10, the misalignment between the upper left portion and the lower right portion is indicated by a white arrow.
Further, the misalignment correction unit 53 calculates the average amount of misalignment for each direction in each unit when the tilt deviation occurs. The average vertical displacement amount and the average lateral displacement amount occurring in the intersecting part such as the upper left and the lower right, and the upper right part and the lower left are the positional deviations in the opposite direction, and the same direction calculated in all the parts. When the difference between the absolute values of the average misalignment amount is equal to or greater than a predetermined threshold value, the misalignment correction unit 53 determines that the tilt deviation has occurred. At this time, the misalignment correction unit 53 performs tilt correction on the reprinted print image data in order to match the reprinted print image data with the preprinted image data.

As described above, the image correction device 1000 corrects the positional deviation between the individual images in the inspection image obtained by forming individual images based on a plurality of image data at different timings on the same recording medium. A correction device, which is a correct answer information acquisition means for acquiring correct answer information including composite image data of a plurality of image data, position information of a boundary portion of adjacent individual images, and image distinction area information capable of distinguishing a plurality of image data. (Correct answer information acquisition unit 51), alignment means (alignment unit 52) for aligning the composite image data and the scanned image data obtained by reading the inspection image formed on the recording medium, and the boundary from the scanned image data. Boundary part detecting means (positional deviation correction part 53) that detects the inspection boundary part based on the position information of the part, and the pixel value of the boundary part of the composite image data and the inspection boundary part of the read image data in the aligned state. A calculation means (positional deviation correction unit 53) that calculates the amount of positional deviation between individual images in the inspection image by comparison, and a determination means (position) that determines the type of positional deviation based on the amount of positional deviation and the image distinction area information. It is provided with a misalignment correction unit 53) and a correction means (position misalignment correction unit 53) for correcting the image formation position of at least one of the plurality of image data according to the misalignment amount and the misalignment type.
Therefore, it is possible to automatically correct the misalignment between the images of the pre-printed image data on the recording medium and the post-printed image data.

Further, the position information of the boundary portion includes edge information of a plurality of image data.
Therefore, it is possible to accurately acquire the boundary portion to be inspected for the misalignment.

Further, the correct answer information includes direction information indicating the directionality of the boundary portion, and the calculation means determines the direction of the positional deviation based on the direction information.
Therefore, the directionality of the boundary portion to be detected for the positional deviation can be determined.

Further, the calculation means calculates the overall average vertical displacement amount and average lateral displacement amount on the recording medium from the vertical and horizontal positional deviation amounts of each inspection boundary portion on the recording medium.
Therefore, the overall amount of misalignment generated on the recording medium can be accurately detected.

Further, the calculation means calculates the vertical shift correction value and the horizontal shift correction value based on the average vertical deviation amount and the average lateral deviation amount on the recording medium.
Therefore, vertical and horizontal shift correction can be applied to the positional deviation that occurs on the recording medium.

Further, the calculation means divides the in-plane on the recording medium into a plurality of regions (N ≧ 2), and averages each region from the amount of vertical and horizontal misalignment of the inspection boundary portion existing in each region. Calculate the amount of vertical displacement and the amount of average lateral displacement.
Therefore, it is possible to accurately detect the detailed amount of misalignment generated on the recording medium.

Further, the calculation means calculates the average vertical deviation amount in one or more regions existing in the upper part and the lower part from the vertical center position of the recording medium divided into N divisions (N ≧ 2), and averages each part. The vertical double correction value is calculated from the vertical displacement amount, and the average lateral displacement amount in one or more regions existing in the left and right portions from the horizontal center position of the divided recording medium is calculated, and the average lateral displacement of each portion is calculated. Calculate the horizontal double correction value from the amount.
Therefore, vertical double and horizontal double correction can be applied to the positional deviation that occurs on the recording medium.

Further, the calculation means divides the in-plane on the recording medium into a plurality of regions (M ≧ 4), and averages each region from the amount of vertical and horizontal misalignment of the inspection boundary portion existing in each region. Calculate the amount of vertical displacement and the amount of average lateral displacement,
The determination means determines the type of positional deviation according to the average vertical displacement amount and the average lateral displacement amount for each area.
Therefore, it is possible to determine the type of misalignment that has occurred on the recording medium.

Further, the calculation means is the upper left portion, the upper right portion, the lower left portion, and the lower right portion based on the center position of the recording medium in each region in which the in-plane on the recording medium is divided into a plurality of regions (M ≧ 4). In this case, the inclination correction value or the rotation correction value is calculated based on the average misalignment amount in the same direction calculated in the section located in the crossing relationship.
Therefore, tilt and rotation correction can be applied to the positional deviation that occurs on the recording medium.

Further, the image correction device 1000 includes a setting means for setting a position shift amount to be corrected.
Therefore, it is possible to correct the misalignment amount arbitrarily set by the user.

The description in the above embodiment shows a suitable example of the image forming apparatus according to the present invention, and is not limited thereto.

Further, in the above embodiment, the image correction device is provided in the image forming device, but the present invention is not limited to this. The image correction device may be a device separate from the image forming device including the image forming unit.

Further, in the above embodiment, the position shift correction is performed on the reprinted print image data, but the present invention is not limited to this. The pre-printed image data may be corrected, or the follow-up print image data and the pre-printed image data may be corrected.

Further, in the above embodiment, the misalignment correction unit 53 calculates the average value of the misalignment amount of the entire surface of the recording medium for each direction, and vertically based on the average misalignment amount for each direction and the image distinction area information. Alternatively, horizontal shift correction is performed, but the present invention is not limited to this. The misalignment correction unit 53 divides the inside of the surface on the recording medium into N-divided (N ≧ 2) regions, from the vertical center to the upper part, the lower part, and from the horizontal center to the left part and the right part with respect to the recording medium surface. The average position shift amount for each direction in each part may be calculated, and the vertical shift correction or the horizontal shift correction may be performed based on the average position shift amount for each direction and the image distinction area information.
In this case, the vertical double correction or horizontal double correction is performed based on the average position shift amount and the image distinction area information for each direction after the vertical shift correction or the horizontal shift correction.
For example, when the vertical average misalignment amount in the upper part is smaller than the vertical average misalignment amount in the lower part, there is a possibility that the vertical misalignment and the vertical double misalignment occur at the same time. In this case, first, vertical shift correction is performed based on the vertical average position shift amount and the image distinction area information of the upper part, and then the vertical shift correction is performed based on the corrected vertical average position shift amount and the image distinction area information of each part. Perform double correction.

In addition, the detailed configuration and detailed operation of the image forming apparatus 100 can be appropriately changed without departing from the spirit of the present invention.

11 Control unit 12 Storage unit 13 Operation unit (setting means)
14 Display unit 20 Image forming unit 30 Image reading unit 40 Cutting unit 50 Correction unit 51 Correct answer information acquisition unit (correct answer information acquisition means)
52 Alignment part (alignment means)
53 Positional deviation correction unit (boundary portion detection means, calculation means, determination means, correction means)
100 Image forming device 1000 Image correction device

Claims (14)

It is an image correction device that corrects the positional deviation between individual images in an inspection image obtained by forming individual images based on a plurality of image data on the same recording medium at different timings and synthesizing them.
A correct answer information acquisition means for acquiring correct answer information including composite image data of a plurality of image data, position information of a boundary portion of adjacent individual images, and image distinction area information capable of distinguishing the plurality of image data.
An alignment means for aligning the composite image data and the read image data obtained by reading the inspection image formed on the recording medium, and
A boundary portion detecting means for detecting an inspection boundary portion based on the position information of the boundary portion from the read image data, and a boundary portion detecting means.
A calculation means for calculating the amount of misalignment between individual images in the inspection image by comparing the pixel values of the boundary portion of the composite image data and the inspection boundary portion of the read image data in the aligned state. When,
A determination means for determining the position shift type based on the position shift amount and the image distinction area information, and
A correction means for correcting the image formation position of at least one of the plurality of image data according to the amount of misalignment and the type of misalignment.
An image correction device equipped with. The image correction device according to claim 1, wherein the position information of the boundary portion includes edge information of the plurality of image data. The correct answer information includes directional information indicating the directionality of the boundary portion.
The image correction device according to claim 1 or 2, wherein the calculation means determines the direction of misalignment based on the direction information. The calculation means calculates the average vertical displacement amount and the average lateral displacement amount on the recording medium from the vertical and horizontal positional deviation amounts of the inspection boundaries on the recording medium, according to claims 1 to 3. The image correction device according to any one of the above. The image correction device according to claim 4, wherein the calculation means calculates a vertical shift correction value and a horizontal shift correction value based on the average vertical shift amount and the average horizontal shift amount on the recording medium. The calculation means divides the in-plane on the recording medium into a plurality of regions (N ≧ 2), and from the amount of positional deviation in the vertical and horizontal directions of the inspection boundary portion existing in each region, for each region. The image correction device according to any one of claims 1 to 4, which calculates the average vertical deviation amount and the average lateral deviation amount. The calculation means calculates the average vertical deviation amount in one or more regions existing in the upper part and the lower part from the vertical center position of the divided recording medium, and corrects the vertical shift from the average vertical deviation amount of each part. The value is calculated, the average lateral displacement amount in one or more regions existing in the left portion and the right portion respectively from the lateral center position of the divided recording medium is calculated, and the lateral shift correction is performed from the average lateral displacement amount of each portion. The image correction device according to claim 6, which calculates a value. The image correction according to claim 7, wherein the vertical double correction value is calculated from the average vertical shift amount of the respective parts after the vertical shift correction or the horizontal shift correction, and the horizontal double correction value is calculated from the average horizontal shift amount of the respective parts. Device. The calculation means divides the in-plane on the recording medium into a plurality of regions (M ≧ 4), and from the amount of vertical and horizontal misalignment of the inspection boundary portion existing in each region, each region. Calculate the average vertical deviation amount and average lateral deviation amount of
The image correction device according to any one of claims 1 to 8, wherein the determination means determines the type of positional deviation according to the average vertical displacement amount and the average lateral displacement amount for each region. The calculation means is the average position deviation in the same direction calculated in the portions located in the crossing relationship when the upper left portion, the upper right portion, the lower left portion and the lower right portion are set with reference to the center position of the recording medium in the region. The image correction device according to claim 9, which calculates a tilt correction value or a rotation correction value based on the amount. The image correction device according to any one of claims 1 to 10, further comprising a setting means for setting the amount of misalignment to be corrected. The image correction device according to any one of claims 1 to 11.
An image forming apparatus including an image forming unit for forming an image on paper. This is an image correction method for correcting the positional deviation between individual images in an inspection image obtained by forming individual images based on a plurality of image data on the same recording medium at different timings and synthesizing them.
A correct answer information acquisition step for acquiring correct answer information including composite image data of a plurality of image data, position information of a boundary portion of adjacent individual images, and image distinction area information capable of distinguishing the plurality of image data.
An alignment step for aligning the composite image data and the read image data obtained by reading the inspection image formed on the recording medium, and
A boundary portion detection step for detecting an inspection boundary portion based on the position information of the boundary portion from the read image data, and a boundary portion detection step.
Positional deviation for calculating the amount of positional deviation between individual images in the inspection image by comparing the pixel values of the boundary portion of the composite image data and the inspection boundary portion of the read image data in the aligned state. Amount calculation step and
A determination step for determining the position shift type based on the position shift amount and the image distinction area information, and
A correction step for correcting the image formation position of at least one of the plurality of image data according to the position shift amount and the position shift type, and
Image correction methods, including. A computer of an image correction device that corrects the positional deviation between individual images in an inspection image obtained by forming individual images based on a plurality of image data on the same recording medium at different timings and synthesizing them.
Correct answer information acquisition means for acquiring correct answer information including composite image data of a plurality of image data, position information of a boundary portion of adjacent individual images, and image distinction area information capable of distinguishing the plurality of image data.
An alignment means for aligning the composite image data and the scanned image data obtained by reading the inspection image formed on the recording medium.
A boundary portion detecting means for detecting an inspection boundary portion from the read image data based on the position information of the boundary portion.
Positional deviation for calculating the amount of positional deviation between individual images in the inspection image by comparing the pixel values of the boundary portion of the composite image data and the inspection boundary portion of the read image data in the aligned state. Quantity calculation means,
Judgment means for determining the type of misalignment based on the amount of misalignment and the image distinction area information,
A correction means for correcting the image formation position of at least one of the plurality of image data according to the amount of misalignment and the type of misalignment.
A program to function as.

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