JP2018005173A - Image forming apparatus and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of flare when image correction is performed on a printed image in real time, even if the printed image and a patch image are arranged on the same surface of a sheet.SOLUTION: An aspect of the present invention comprises: a print image analysis part that analyzes the arrangement of a print image formed on an image forming area of a sheet with respect to the sheet; and a patch image position determination part that determines the position of a patch image for image correction formed outside the image forming area of the sheet on the basis of a result of analysis performed by the print image analysis part.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an image forming apparatus and program for reading a patch image for density adjustment, and more particularly to arrangement of a patch image.

  In an image forming apparatus, a correction image (patch image) may be drawn on a sheet to stabilize the image. For example, a color patch image for density adjustment is formed on a sheet (see FIG. 1), the formed color patch image is measured by an in-line sensor, and the density of the image forming apparatus is adjusted based on the measurement result.

FIG. 1 is a diagram illustrating an example of a conventional general patch image.
An image is formed in the image forming area ImA of the paper S, and the periphery of the image forming area ImA is cut. In general, a patch image for image correction in real time is formed in a portion to be cut around the image forming area ImA (outside the image forming area). In FIG. 1, a patch image AP is formed outside the image forming area along the paper conveyance direction (sub-scanning direction). The patch image AP includes four color patch images including a yellow patch image Py, a magenta patch image Pm, a cyan patch image Pc, and a black patch image Pk.

  On the other hand, it is known that a phenomenon called “flare” occurs in an inline sensor due to the influence of an image around the measurement target, and the color information of the measurement target cannot be accurately read. On the other hand, for example, Patent Document 1 proposes a method of determining a density correction value based on a white data reading result and a background color reading result in the vicinity of a patch that does not cause flare for a density adjustment patch. Yes.

JP 2009-10837 A

  However, the technique described in Patent Document 1 does not refer to the arrangement of patch images when image correction is performed on image data (printed image) in real time. Therefore, when it is desired to arrange the patch image on the same plane as the image data, there is a possibility that flare occurs.

  From the above situation, it has been desired to suppress the occurrence of flare when a print image and a patch image are arranged on the same side of a sheet.

An image forming apparatus according to an aspect of the present invention includes a print image analysis unit and a patch image position determination unit.
The image analysis unit analyzes the arrangement of the print image formed in the image forming area of the paper with respect to the paper. The patch image position determining unit determines the position of the patch image formed outside the image forming area of the paper based on the analysis result of the print image analyzing unit.

According to at least one aspect of the present invention, the patch image is formed at a position where no flare of the paper occurs according to the arrangement of the print image. Therefore, even when the print image and the patch image are arranged on the same side of the paper, the occurrence of flare can be suppressed.
Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is a figure which shows the example of the conventional general patch image. 1 is a schematic diagram illustrating a system configuration example of an image forming apparatus according to a first embodiment of the present invention. 2 is a block diagram illustrating an example of a control system of the image forming apparatus according to the first exemplary embodiment of the present invention. FIG. It is a block diagram which shows the function structural example of the control apparatus which concerns on the 1st Embodiment of this invention. 3 is a flowchart illustrating patch image printing processing according to the first embodiment of the present invention. 6 is a flowchart showing a subroutine of print image arrangement position analysis processing of FIG. 5. 6 is a flowchart showing a subroutine of patch image formation position determination processing of FIG. 5. 5 is a flowchart showing image correction processing after patch image formation according to the first embodiment of the present invention. It is a figure which shows an example of a patch image. It is a figure which shows the 1st example of print data. It is a figure which shows the 2nd example of print data. It is a figure which shows the 3rd example of print data. It is a figure which shows the 4th example of print data. It is a figure which shows the 1st example of the patch image which concerns on the 1st Embodiment of this invention. It is a figure which shows the 2nd example of the patch image which concerns on the 1st Embodiment of this invention. It is a figure which shows the 3rd example of the patch image which concerns on the 1st Embodiment of this invention. It is a figure which shows the example of the print image and patch image which concern on the 2nd Embodiment of this invention. It is a figure which shows an example of GUI which concerns on the 2nd Embodiment of this invention.

  Hereinafter, an example of an embodiment for carrying out the present invention will be described with reference to the accompanying drawings. The description will be given in the following order. In addition, in each figure, about the component which has the substantially same function or structure, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

<1. First Embodiment>
[Entire configuration of image forming apparatus]
FIG. 2 is a schematic diagram showing a system configuration example of the image forming apparatus according to the first embodiment of the present invention. FIG. 2 shows elements considered necessary for explaining the present invention or related elements, and the image forming apparatus is not limited to this example.

(Image forming device main unit)
The image forming apparatus 1 includes an image forming apparatus main body 10 and an inspection unit 40. The inspection unit 40 is connected in series with the paper discharge side of the image forming apparatus main body 10. The image forming apparatus main body 10 forms a print image included in the received job on a sheet for each page, and performs image correction based on the patch image in parallel with the formation of the print image.

  The image forming apparatus main body 10 employs an electrophotographic system in which an image is formed using static electricity. For example, four colors (basic, yellow (Y), magenta (M), cyan (C), and black (K) are used. This is a tandem color image forming apparatus that superimposes color) toner images. The image forming apparatus main body 10 includes paper feed trays 20A and 20B, an image forming unit 30, an image input unit 11 including an automatic document feeder (ADF) 12, and an operation display unit 13. The paper feed trays 20A and 20B are assumed to be capable of feeding long paper that is longer in the paper transport direction than normal paper, in addition to paper of a general size. Further, the image forming apparatus main body 10 is formed with a conveyance path 21 that conveys the paper S fed from the paper feed trays 20A and 20B or the manual feed tray. The transport path 21 is provided with a plurality of rollers (transport rollers) for transporting the paper S.

  The image forming unit 30 includes four image forming units 31Y, 31M, 31C, and 31K in order to form toner images of colors of yellow, magenta, cyan, and black. The image forming units 31Y, 31M, 31C, and 31K may be collectively referred to as the image forming unit 31. Each image forming unit 31 includes a charging unit (not shown), an LED writing unit (laser light source), a developing unit, and a photosensitive drum. The image forming unit 30 includes an intermediate transfer belt 34, a secondary transfer unit 35, and the like, on which images formed on the photosensitive drums 32Y, 32M, 32C, and 32K of the image forming units 31Y, 31M, 31C, and 31K are transferred. A fixing unit 36 is provided downstream of the secondary transfer unit 35 in the sheet conveyance direction. The photosensitive drums 32Y, 32M, 32C, and 32K may be collectively referred to as the photosensitive drum 32.

  On the downstream side of the fixing unit 36 in the paper conveyance direction, the conveyance path 21 extends and is connected to the paper discharge port. Further, a reverse conveyance path 23 is connected to the conveyance path 21 so as to branch on the downstream side of the fixing unit 36 and join the conveyance path 21 on the upstream side of the secondary transfer unit 35. A reversing unit 22 for reversing the paper S is provided in the reversing conveyance path 23. The reversing unit 22 reverses the sheet S conveyed from the fixing unit 36 and conveys the sheet S to the conveying path 21 on the upstream side of the secondary transfer unit 35 through the reversing conveying path 23. Further, the reversing unit 22 can return the reversed paper S to the transport path 21 on the downstream side of the fixing unit 36 and discharge it as it is.

  An operation display unit 13 is installed on the upper part of the image forming apparatus main body 10. The operation display unit 13 has a function as an operation unit that instructs the start of a job such as an image forming process. The operation display unit 13 is provided with a display unit (not shown) made of a liquid crystal panel or the like and an operation unit (not shown) made of a touch panel or the like. The display unit can display the contents of operation by the user, setting information, and the like. Note that the operation display unit 13 may be configured with a mouse, a tablet, or the like, and may be configured separately from the display unit.

  In the image forming mode, the image forming apparatus main body 10 charges the photosensitive drum 32 included in the image forming unit 31 of each color and exposes the surface of the photosensitive drum 32 in accordance with the document image. A latent image is formed. Then, toner is attached to the electrostatic latent image on the photosensitive drum 32 corresponding to each of yellow, magenta, cyan, and black by using a developing unit to form a toner image of each color. Next, the toner images formed on the yellow, magenta, cyan, and black photoconductive drums 32 are sequentially primary-transferred onto the surface of the intermediate transfer belt 34 that is rotationally driven.

  Next, each color toner image primarily transferred onto the intermediate transfer belt 34 is secondarily transferred onto the sheet S conveyed through the conveyance path 21 by the secondary transfer unit 35 (secondary transfer roller). The toner images of the respective colors on the intermediate transfer belt 34 are secondarily transferred to the paper S, whereby a color image is formed. The image forming apparatus main body 10 discharges the sheet S on which the color toner image is formed to the fixing unit 36.

  The fixing unit 36 is a device that performs a fixing process on the sheet S on which a color toner image is formed, which is supplied from the image forming apparatus 1. The fixing unit 36 pressurizes and heats the conveyed paper S, and fixes the transferred toner image on the paper S. The fixing unit 36 includes, for example, an upper fixing roller and a lower fixing roller that are fixing members. The upper fixing roller and the lower fixing roller are arranged in pressure contact with each other, and a fixing nip portion is formed as a pressing portion between the upper fixing roller and the lower fixing roller.

  A heating unit is provided inside the fixing upper roller. The roller part at the outer peripheral part of the fixing upper roller is heated by the radiant heat from the heating part. The sheet S is transported to the fixing nip so that the surface (fixed target surface) onto which the toner image is transferred by the secondary transfer unit 35 faces the fixing upper roller. The sheet S passing through the fixing nip portion is pressed by the upper fixing roller and the lower fixing roller and heated by the heat of the roller portion of the upper fixing roller. The sheet S on which the fixing process has been performed by the fixing unit 36 is conveyed to the inspection unit 40.

(Inspection unit)
An inspection unit 40 having a conveyance path connected to the conveyance path 21 is disposed at the subsequent stage of the image forming apparatus main body 10. An inline sensor 41 that reads an image (output image) formed on the paper S conveyed from the image forming apparatus main body 10 is provided in the conveyance path from the paper S entrance of the inspection unit 40 to the paper discharge tray 50. ing. The inline sensor 41 (an example of an image reading unit) is installed above the conveyance path, and reads an image formed on the upper surface of the conveyed paper S. The inspection unit 40 reads the image formed on the paper S by the inline sensor 41 and then discharges the paper S to the paper discharge tray 50. The read image is transmitted to the control device 100 (see FIG. 3).

  As the in-line sensor 41, a line sensor in which a plurality of photoelectric conversion elements (not shown) are linearly arranged over the entire area in the paper width direction (direction orthogonal to the paper transport direction: main scanning direction) is used. Alternatively, an image sensor in which photoelectric conversion elements are arranged in a matrix may be used as the inline sensor 41. The in-line sensor 41 irradiates the output image formed on the paper S with a beam having a beam spot having a predetermined diameter from a light source included in each of the photoelectric conversion elements. Then, the in-line sensor 41 separates the reflected light into, for example, R (red), G (green), and B (blue) and acquires each reflectance information to read the output image, and determines the color of the read image. Detect. The read color (for example, RGB) is converted into the four basic colors (YMCK) of the image forming apparatus body 10 by, for example, a color conversion profile.

  As the line sensor and the image sensor, a CCD type image sensor or a CMOS type (including MOS type) image sensor can be used. Although the inline sensor 41 is disposed above the conveyance path, an inline sensor may be installed below the conveyance path so that images on both sides of the sheet S are read by one conveyance. Further, the inline sensor may be disposed on the downstream side of the fixing unit 36 in the sheet conveyance direction, and may be disposed in the image forming apparatus main body 10.

  Note that the inspection unit 40 may have the function of a post-processing device. The post-processing function performs post-processing as necessary on the paper S on which the toner image supplied from the image forming apparatus main body 10 is formed. Examples of the post-processing function include sorting, stapling, punching, and folding.

  The configuration and function of the inspection unit 40 may be integrated with the image forming apparatus main body 10. That is, the configuration and function of the inspection unit 40 may be mounted on the downstream side of the fixing unit 36 in the sheet conveyance direction.

[Control system of image forming apparatus]
Next, a control system of the image forming apparatus main body 10 will be described.
FIG. 3 is a block diagram illustrating an example of a control system of the image forming apparatus according to the first embodiment of the present invention. FIG. 3 shows elements considered necessary for explaining the present invention or related elements, and the control system of the image forming apparatus is not limited to this example.

  The image forming apparatus main body 10 includes a control device 100 (an example of a control unit) that performs a series of controls for feeding paper S, forming an image, and discharging the paper S, and a storage device 101. The control device 100 includes an arithmetic processing device including a CPU (Central Processing Unit) (not shown) and a memory such as a RAM (Random Access Memory) and a ROM (Read Only Memory). The ROM stores a program executed by the CPU of the control device 100 or data used when the program is executed. An MPU (Micro-Processing Unit) may be used instead of the CPU.

  The storage device 101 is an example of a storage unit, and stores parameters used when the CPU of the control device 100 executes a program, data obtained by executing the program, and the like. For example, the storage device 101 stores patch image information. A program executed by the CPU of the control device 100 may be stored in the storage device 101.

  The control device 100 receives an operation signal from the operation display unit 13 and performs control according to the operation signal. In addition, the control device 100 outputs a display signal to the operation display unit 13, and the operation display unit 13 displays an operation screen for displaying various setting screens and various processing results for inputting various operation instructions and setting information. Display on the panel.

  Further, the control device 100 acquires color information of the read image detected by the inline sensor 41 of the inspection unit 40, and uses the color information of the read image, for example, an image density, an image position, and a color misregistration correction amount (correction). Value) and feedback (image correction) to the print image of the next page and thereafter.

  The communication I / F 102 is an interface that transmits / receives data to / from a personal computer (PC) 120 that is an operation terminal via a network or a dedicated line. As the communication I / F 102, for example, a NIC (Network Interface Card) is used.

  The paper transport unit 103 drives the transport path 21, the reversing unit 22, and the reverse transport path 23 under the control of the control device 100.

  The normal operation (printing operation) in which the image forming apparatus main body 10 forms an image on the paper S will be described. The control device 100 controls the paper transport unit 103 to transport the paper S. The control device 100 forms an image on the paper S by controlling the image forming unit 30 based on the image data acquired from the document by the image input unit 11 or the image data acquired from the outside. Then, the control device 100 controls the fixing unit 36 to fix the image on the paper S, and conveys the paper S on which the image is formed to the inspection unit 40. The control device 100 controls the inspection unit 40 to discharge the paper S to the paper discharge tray 50. Further, the control device 100 reads an output image formed on the paper S by the in-line sensor 41, adjusts an image forming parameter (image forming condition) for each basic color based on the color information of the read image, and corrects the image.

[Functional configuration of control device]
Next, functions executed by the control device 100 will be described.
FIG. 4 is a block diagram illustrating an example of a functional configuration of the control device 100. The control device 100 includes a print data acquisition unit 111, a print image analysis unit 112, a patch image position determination unit 113, a patch image synthesis unit 114, a patch image position storage unit 115, a read image analysis unit 116, a correction value calculation unit 117, and An image correction unit 118 is provided. The function of each part of the control device 100 is realized by the CPU executing a program stored in the ROM as an example.

  The print data acquisition unit 111 acquires print data included in a job transmitted from the PC 120 via the communication I / F 102, for example. The print data acquisition unit 111 outputs a print image generated by performing rasterization processing on the print data to the print image analysis unit 112. If the acquired print data is already rasterized, the print data acquisition unit 111 outputs the print data as it is to the print image analysis unit 112.

  The print image analysis unit 112 analyzes the arrangement of the print image on the paper formed in the image formation area of the paper output from the print data acquisition unit 111. Note that the print image input to the print image analysis unit 112 has been subjected to the rasterization process, but may be the one before the rasterization process.

The patch image position determination unit 113 determines the formation position of the patch image for image correction formed outside the image formation area based on the analysis result of the print image analysis unit 112.
For example, the patch image position determination unit 113 determines from the analysis result of the image analysis unit 1112 whether or not the print image is separated from one end of the image forming area by a predetermined distance (threshold of a distance at which no flare occurs) or more in the main scanning direction. To do. Then, the patch image position determination unit 113 arranges the patch image on one end side of the image forming area out of the image forming area when the print image is separated from the one end of the image forming area by a predetermined distance or more.
Further, the patch image position determination unit 113 further generates flare in the patch image based on the color information of the print image when the print image is not separated from the one end of the image forming area by a predetermined distance or more in the main scanning direction. Place it in a position where it is difficult to do.

  The patch image combining unit 114 (an example of a print image moving unit) combines the patch image with the print image to generate image forming data, and outputs the image forming data to the image forming unit 30. The image forming unit 30 forms a print image and a patch image on a sheet based on the image forming data. Further, the patch image composition unit 114 performs a process of changing the position (arrangement) of the print image in accordance with an instruction from the patch image position determination unit 113.

  The patch image position storage unit 115 stores the patch image formation position (formation region) determined by the patch image position determination unit 113.

  The read image analysis unit 116 analyzes the color information of the position of the patch image stored by the patch image position storage unit 115 from the read image read by the inline sensor 41.

  The correction value calculation unit 117 calculates the correction value of the print image for the next page and subsequent pages based on the analysis result of the read image analysis unit 116.

  Based on the correction value calculated by the correction value calculation unit 117, the image correction unit 118 corrects the print image of the next page and thereafter.

[Patch image printing]
Next, processing for printing a patch image in the image forming apparatus 1 (image forming apparatus main body 10) will be described.

FIG. 5 is a flowchart showing a patch image printing process according to the first embodiment.
The control device 100 implements the processing shown in FIG. 5 (the same applies to FIGS. 6 to 8 described later) by executing a program recorded in a ROM (not shown).

  First, the print data acquisition unit 111 of the image forming apparatus body 10 acquires print data included in the received job (S1).

  Next, the print image analysis unit 112 analyzes the arrangement of the print image acquired by the print data acquisition unit 111 with respect to the paper (S2).

  Next, the patch image position determining unit 113 determines the position of the patch image formed outside the image forming area based on the analysis result of the print image analyzing unit 112 (S3). The patch image synthesis unit 114 generates image formation data obtained by synthesizing the patch image with the print image, and outputs the data to the image formation unit 30.

  Then, the image forming unit 30 forms a print image and a patch image on a sheet based on the image forming data output from the patch image combining unit 114 (S4).

(Printed image layout analysis processing)
Here, the subroutine (print image arrangement position analysis process) in step S2 of FIG. 5 will be described.
FIG. 6 is a flowchart showing the print image arrangement position analysis processing in step S2. This process is a method of analyzing the arrangement position of the print image in the sub-scanning direction and detecting whether the print image is separated from the edge of the image forming area by a threshold value that does not cause flare.

First, the print image analysis unit 112 sets the initial value of the line number i in the sub-scanning direction to be analyzed to 0 (i = 0) (S11). Further, the print image analysis unit 112 sets the initial value of the element j of the region X _M [j] in the print image to 0 (j = 0) (S12). i and j are integers of 0 or more. The print image analysis unit 112 analyzes the arrangement positions of the print images for all line numbers N in the sub-scanning direction (S13 to S19).

  At this time, since it is known that which color patch image is susceptible to the print image depends on the color information of the print image existing in the vicinity, a plurality of threshold values (that is, the dominant print image) For each basic color) (S14 to S18). The threshold type is a type of basic color, and in this embodiment, is yellow (Y), magenta (M), cyan (C), and black (K). A threshold (a distance at which no flare occurs) is set in advance for each YMCK and stored in the storage device 101.

  First, when the line number i in the sub-scanning direction is ‘0’, the print image analysis unit 112 starts analyzing the arrangement of the print image based on the threshold value for Y color as the threshold type (S14).

  Next, the print image analysis unit 112 determines that the print image is in the main scanning direction (direction orthogonal to the sub-scanning direction) from the end of the image forming area (for example, the image forming area ImA with the registration marks T1 to T4 in FIG. 13 as vertices). It is determined whether or not the distance is more than the threshold (S15). That is, it is determined whether or not there is a print image (image data) from the edge of the image forming area over a threshold value or more. From this determination result, it can be determined whether or not the print image exists at a position where there is a possibility of causing flare.

  In step S15, there are two end portions of the image forming area in the main scanning direction (for example, the upper end side and the lower end side of the image forming area ImA in FIG. 13), and the above determination is performed for both end portions. .

  When the print image is not separated from the edge of the image forming area by a threshold or more in the main scanning direction (NO in S15), the print image analysis unit 112 increments the value of the element j and sets the next element 'j + 1' as (S16).

On the other hand, if the print image is more than the threshold in the main scanning direction from the edge of the image formation area (YES in S15), the print image analysis unit 112 sets the value of the area X _M [j] in the print image. Increment and set X _M [j] = X _M [j] +1 (S17).

  Next, after the processing of step S16 or S17 is completed, the print image analysis unit 112 performs print image arrangement for all threshold types (basic colors) in the current line number in the sub-scanning direction (here, 0). It is determined whether the analysis is completed (S18). If the analysis has not been completed, the print image analysis unit 112 proceeds to step S14 and continues the analysis of the print image arrangement for the next threshold type. On the other hand, when the analysis of the layout of the print image is completed with the line number, the process proceeds to step S19.

  Next, the print image analysis unit 112 determines whether or not the line number i in the sub-scanning direction has reached the last line number N (S19), and if the line number i has not reached N, i Is incremented. Then, the process proceeds to step S13, and the analysis of the layout of the print image is continued for the next line number “i + 1”. In this example, the line number in the sub-scanning direction to be analyzed is changed to “1”, and the analysis of the layout of the print image is started based on the threshold value corresponding to the color information in the line number “1” of the print image. .

  If the line number i reaches N in step S19, the print image analysis unit 112 ends the print image arrangement position analysis process.

  By the above-described print image arrangement position analysis processing, it is determined how many lines in the sub-scanning direction there are continuous areas where no flare occurs on the image forming area.

For example, in the example of the print image shown in FIG. 13, X _M (0) is defined as an area where the print image is a predetermined distance (here, dx) away from the end of the image forming area ImA in the main scanning direction. (Dx) X _M (1) to X _M (n) are detected as non-separated areas. Here, n ≦ N. N and n are integers of 0 or more. The black data Kd in the area X _M (0) indicates an image area where black is dominant, and the yellow data Yd in the areas X _M (1) to X _M (n) indicates an image area where yellow is dominant.

If the print image is not separated from the edge of the image forming area ImA by a threshold or more in a continuous section in the sub-scanning direction, NO and S16 in S15 are repeated. In the areas X _M (1) to X _M (n), the print image is not separated from the end of the image forming area ImA by the threshold value dx or more, so the value of the element j of X _M (j) is incremented sequentially. is there. For example, as shown in the yellow data Yd in FIG. 13, the configuration area increases as X _M (1), X _M (2). Each section (length) of this constituent area is 0 (X _M (1) = 0, X _M (2) = 0,...).

Yellow data Yd interval dz ₂ of a length corresponding to the number of lines in the sub-scanning direction of the yellow data Yd, yellow data Yd is the same number as the number of the sub-scanning direction line region _X M (1) _~X M ( n). That is, each of the regions X _M (1) to X _M (n) corresponds to one line. Here, each of the areas X _M (1) to X _M (n) has a value of 0 because it is not separated from the edge of the image forming area ImA by more than a threshold, and the area X _M (1) to the area X _M ( The sum of the values up to n) is zero. That is, there is no continuous region that is more than the threshold from the end of the image forming region ImA between the region X _M (1) and the region X _M (n).

If the print image is continuously separated from the edge of the image forming area ImA by a threshold or more in the sub-scanning direction, S15 YES and S17 are repeated. For example, as shown in the black data Kd in FIG. 13, the configuration area remains X _M (0) even if the line number i changes. In the section (length) of the configuration area, the value of X _M (0) is incremented as needed, and X _M (0) = dz ₁ is obtained.

  In FIG. 6, it is determined whether or not the print image is separated from the edge of the image forming area by a threshold value or more in the main scanning direction for the threshold type (basic color) for a certain line of the print image. Absent. For example, first, it is determined whether or not the print image is separated from the edge of the image forming area in the main scanning direction by a threshold (dx) or more that does not cause flare for all color patch images Py, Pm, Pc, and Pk. If the distance is not more than the threshold value dx, the distance of the print image from the edge of the image forming area may be determined for the threshold type (basic color). If the distance from the edge of the image formation area of the print image is greater than or equal to the threshold value dx, discrimination for each basic color can be omitted, and the processing load on the print image analysis unit 112 is reduced.

(Patch image formation position determination process)
Here, the subroutine (patch image formation position determination process) in step S3 in FIG. 5 will be described.
FIG. 7 is a flowchart showing the patch image formation position determination process in step S3. In this process, it is determined whether a patch image can be formed in the detected continuous area outside the image forming area based on the analysis result of the print image arrangement in FIG. 6, and if it can be formed, the patch image is additionally formed. Is the method.

  First, the patch image position determination unit 113 performs a patch image formation position determination process for the corresponding threshold type (basic color) (S21 to S27).

At this time, the patch image position determination unit 113 performs the patch image formation position determination process for the number of elements in the region X _M (j) detected in the print image arrangement position analysis process of FIG. 6 (S22 to S26). .

Patch image position determining unit 113 determines whether it is possible to form an image patch in an area _{X M (j) (S23)} , if unable to form an image patch in an area _X M (j) of (S23 NO ), The process proceeds to step S26. The patch image position determining unit 113 determines that the patch image can be formed when the patch image is not affected by the flare or is extremely small, and determines that the patch image cannot be formed when the patch image is affected by the flare.

On the other hand, when an image patch can be formed in the region X _M (j) (YES in S23), the patch image position determination unit 113 sets the corresponding region X _M (j) to the patch image ( (Color patch image) formation position. Then, the patch image composition unit 114 adds (synthesizes) the patch image to the corresponding position (in the region X _M (j)) of the print image (S24), and generates image formation data.

  Next, the patch image position storage unit 115 stores the position of the patch image determined by the patch image position determination unit 113 (S25).

Next, the patch image position determination unit 113 determines whether or not the determination as to whether or not the image patch can be formed for all the elements in the region X _M (j) has been completed (S26). In step S22, the same determination is performed for the next region X _M (j + 1). On the other hand, when the next region X _M (j) does not exist, the patch image position determination unit 113 proceeds to the process of step S27.

For example, in the example of FIG. 12, in the case of the region X _M (0) corresponding to the black data Kd, the yellow patch image Py can be formed outside the image forming region (see the lower side of FIG. 12, see FIG. 15). . Further, in the case of the regions X _M (1) to X _M (n) corresponding to the yellow data Kd, color patch images Pm, Pc, Pk other than Y color can be formed (see the lower side of FIG. 12, FIG. 15). ).

  Next, the patch image position determination unit 113 determines whether or not the patch image formation position determination process has been completed for all threshold types (basic colors) (S27). If not, the process proceeds to step S21. The patch image formation position determination process is continued for the next threshold type. On the other hand, if there is no patch image for which the formation position is to be determined, the patch image position determination unit 113 ends the patch image formation position determination process.

In S23 of FIG. 7, the maximum area X _M (j) where a patch image can be formed may be detected, and it may be determined whether or not a patch image of all colors can be formed using only the area X _M (j). . If the patch image can be divided and arranged, it may be divided and arranged.

[Image correction processing]
Next, an image correction process performed after the patch image is formed in the image forming apparatus 1 (image forming apparatus body 10) will be described.
FIG. 8 is a flowchart showing image correction processing after patch image formation according to the first embodiment.

  First, the control device 100 determines whether or not a patch image has been formed on a sheet based on the result of the patch image formation position determination process of FIG. 7 (S31). Here, when the patch image is not formed (NO in S31), the control device 100 performs control so as not to perform the image correction on the next page (S36), and after the process of step S36 is completed, this flowchart. The image correction process is terminated.

  Next, when the patch image is formed (YES in S31), the control device 100 reads the image formed on the paper using the inline sensor 41 (S32).

  Next, the read image analysis unit 116 analyzes the color information of the position stored in the patch image position storage unit 115 from the read image of the inline sensor 41 (S33).

  Next, the correction value calculation unit 117 calculates the correction value of the print image for the next page and subsequent pages based on the analysis result of the read image analysis unit 116 (S34).

  Next, the image correcting unit 118 performs image correction on the next page based on the correction value calculated by the correction value calculating unit 117 (S35).

  Hereinafter, an example of a patch image formed on a sheet according to the arrangement of print images in the present embodiment will be described with specific examples.

[Patch image example]
FIG. 9 is a diagram illustrating an example of a patch image according to the first embodiment.
The patch image AP is an example of a patch image formed on a sheet together with a print image. The patch image AP includes four basic color patch images, a yellow patch image Py, a magenta patch image Pm, a cyan patch image Pc, and a black patch image Pk. The density of each color patch image Py, Pm, Pc, Pk changes stepwise. The overall length of the patch image AP is dy, and the length of each color patch image is dy ₁ .

[Example of printed image]
FIG. 10 is a diagram illustrating a first example of a print image.
In FIG. 10, register marks T1 to T4 are formed near the four corners of the sheet S, respectively. For example, the registration marks T1 to T4 are position reference marks and serve as a reference for the cutting position. In the present embodiment, the positions of the register marks T1 to T4 coincide with the four corners of the image forming area ImA. In FIG. 10, black data Kd (print image) is arranged in the entire area of the image forming area ImA.

  Note that the black data Kd indicates the dominant color (basic color) of the print image, and the entire print image is not black. For example, if the dominant color of the print image is yellow, it is yellow data Yd, if it is magenta, it becomes magenta data Md, and if it is cyan, it becomes cyan data Cd. When analyzing the color tendency (dominant color) of the print image, for example, attribute information (for example, tag bit data) for each pixel included in the job (print data) is acquired and analyzed. At this time, the color information may be analyzed only for a portion (for example, a predetermined number of pixels close to the end portion) near the end portion of the image forming area ImA of the print image.

FIG. 11 is a diagram illustrating a second example of a print image.
In FIG. 11, black data Kd (printed image) is arranged at a position where no flare occurs (distance threshold dx) with respect to all color patch images Py, Pm, Pc, and Pk. That is, the distance in the main scanning direction from the end of the image forming area ImA of the black data Kd (the straight line connecting the register marks T3 and T4) is more than the threshold value dx. This threshold value dx is a preset value and is stored in the storage device 101.

FIG. 12 is a diagram illustrating a third example of a print image.
In FIG. 12, the area X _M (0) of the black data Kd (printed image) is arranged at a position where no flare occurs (distance threshold dx) for all color patch images Py, Pm, Pc, Pk. Yes. The length of the region X _M (0) in the sub-scanning direction is the section dz ₁ . That is, the distance in the main scanning direction from the end of the image forming area ImA of the black data Kd (the straight line connecting the register marks T3 and T4) is more than the threshold value dx. The length of the section dz ₁ is longer than the length dy _{1 of one} patch image (dz ₁ > dy ₁ ).

After that (on the right side of the black data Kd in the figure), only the yellow patch image Py is affected by the flare (distance threshold dx ₁ ), and the region X _M (yellow image Yd (printed image)) 1) is arranged. Sub-scanning direction length of the region _X M (1) is a section dz _2. The distance of the end of the image formation region ImA yellow data Yd from (straight line connecting the dragonfly T3, T4) in the main scanning direction is between threshold dx and the threshold dx _1. The threshold value dx ₁ is shorter than the threshold value dx. The length of the section dz ₂ is longer than the length (dy ₁ × 3) of three patch images (dz ₂ > (dy ₁ × 3)).

FIG. 13 is a diagram illustrating a fourth example of a print image.
In FIG. 13, the area X _M (0) of the black data Kd (printed image) is arranged at a position where no flare occurs (distance threshold dx) with respect to the patch images Py, Pm, Pc, and Pk of all colors. Yes. The length of the region X _M (0) in the sub-scanning direction is the section dz ₁ . That is, the distance in the main scanning direction from the end of the image forming area ImA of the black data Kd (the straight line connecting the register marks T3 and T4) is more than the threshold value dx. The length of the section dz ₁ is longer than the length dy _{1 of one} patch image (dz ₁ > dy ₁ ).

After that, the areas (1) to X _M (n) of the yellow data Yd are arranged at positions where flare occurs for the patch images Py, Pm, Pc, and Pk of all colors. Sub-scanning direction length of the region _X M (1) ~ region _X M (n) is a section dz _2. The distance of the end of the image formation region ImA yellow data Yd from (straight line connecting the dragonfly T3, T4) in the main scanning direction, closer than the threshold dx _1. The length of the section dz ₂ is longer than the length (dy ₁ × 3) of three patch images (dz ₂ > (dy ₁ × 3)).

Furthermore, on the opposite side of the image forming region ImA (dragonfly T1, T2 side), over the interval _dz 3 corresponding to the entire section of the image forming area _{ImA (= dz 1 + dz 2} ), all the colors of the patch image Py, Pm, Black data Kd and yellow data Yd are arranged at a position where no flare occurs with respect to Pc and Pk (distance threshold dx).

[Patch image example]
(In the case of the print image of the first example)
Based on step S2 in FIG. 5 (that is, S11 to S19 in FIG. 6), the control apparatus 100 analyzes whether the print image is separated from one end of the image forming area ImA by a predetermined distance (threshold value dx) or more in the main scanning direction. To do. Regarding the print image (FIG. 10) of the first example, the control device 100 does not have any area (section) that is separated from one end of the image forming area ImA by more than the threshold (dx) in all the areas (sections) in the sub-scanning direction. (S15 to S17 in FIG. 6).

  The control device 100 determines the arrangement position of the patch image based on step S3 in FIG. 5 (that is, S21 to S27 in FIG. 7). The control device 100 does not form a patch image because there is no blank area that is separated from the edge of the image forming area ImA by a threshold or more with respect to the print image of FIG. 10 (S23). Since there is no patch image formation, the control device 100 controls not to perform the correction process for the next page (S36 in FIG. 8).

(Example of patch image for print image of second example)
FIG. 14 is a diagram illustrating a first example of a patch image according to the first embodiment.
The control device 100 determines that the print image (FIG. 11) of the second example is separated from one end of the image forming area ImA by a threshold (dx) or more in all areas (sections) in the sub-scanning direction (FIG. 11). 6 S15-S17).
For example, the control device 100 calculates the maximum area from the area X _M (j) where the detected patch image can be formed (S23 in FIG. 7). Since the control device 100 can form patch images in all regions (sections) of the print image in FIG. 11, the formation positions of all color patch images Py, Pm, Pc, and Pk are set to the images on the registration marks T3 and T4 side. Control is made so that it is disposed outside the formation region (S24). The formation positions of all color patch images are stored in the storage device 101 (S25).

(Example of patch image for print image of third example)
FIG. 15 is a diagram illustrating a second example of the patch image according to the first embodiment.
Controller 100 relates the third print image (FIG. 12), as formable area patch image, detecting a section dz ₁ black data Kd, yellow data Yd section dz ₂ (distance threshold dx ₁₎ (S15 to S17 in FIG. 6).
The section dz ₁ is a section in which no flare occurs with respect to the patch images Py, Pm, Pc, and Pk of all colors (the distance from the end of the image forming area is dx or more), and the section dz ₂ is only the patch image Py for yellow. flare is an interval that occurs (between the distance from the image forming area edge is dx ₁ and dx). Therefore, the control device 100 arranges the patch image Py for yellow at a position corresponding to the section dz ₁ of the black data Kd, and other patch images Pm, Pc, Pk correspond to the section dz ₂ of the yellow data Yd. Place in position. In this manner, the patch images are rearranged so that all color patch images Py, Pm, Pc, and Pk are arranged on one side outside the image forming area (S23 to S25 in FIG. 7).

If the length of the black data Kd in the sub-scanning direction (section dz ₁ ) is short (dz ₁ ≦ dy ₁ ) and the yellow patch image Py cannot be arranged, the patch image Py is arranged on the next sheet. You may make it do. Alternatively, a method may be considered in which the patch image Py for yellow is not arranged and the patch image Py is not used for the current image correction. Even in this case, since the image correction is performed based on the patch images of three colors other than yellow, a certain image quality can be ensured.

(Example of patch image for print image of fourth example)
FIG. 16 is a diagram illustrating a third example of the patch image according to the first embodiment.
The control device 100 relates to the fourth print image (FIG. 13) as an area (section) in which a patch image can be formed, the section dz ₁ of one black data Kd in the main scanning direction and the other black in the main scanning direction. It detects a section dz ₃ spanning from data Kd yellow data Yd (S15 to S17 in FIG. 6).
The section dz ₁ is a section where the flare does not occur for the patch images Py, Pm, Pc, and Pk of all colors (the distance from the end of the image forming area is dx or more), but only one patch image can be arranged. On the other hand, the section dz ₃ on the opposite side is a section in which no flare occurs for the patch images Py, Pm, Pc, and Pk of all colors. Therefore, the control unit 100, a patch image Pk for black is disposed in a position corresponding to the section dz ₁ at one end of the black data Kd outside the image forming region, outside the image forming area the other end of the black data Kd yellow data Yd to span interval dz ₃ in the patch image Py in the corresponding position, Pm, to place the Pc.

In FIG. 16, only the patch image Pk for black is arranged on one end side outside the image forming area. However, since the section dz ₃ is large enough to arrange the patch images Py, Pm, Pc, and Pk for all colors, the section dz. _{In FIG. 3} , patch images Py, Pm, Pc, and Pk of all colors may be arranged.

  As shown in FIG. 16, when the patch images of all colors cannot be arranged on one end side (lower side in FIG. 16) outside the image forming area of the paper S, they may be arranged outside the opposite image forming area. Further, for each color patch image, it may be determined on which side outside the image forming area. That is, regardless of the layout of the print image, the patch images of all colors may be divided and arranged on both one end side and the other end side outside the image forming area.

  According to the first embodiment described above, the patch image is formed at a position where the flare of the paper does not occur according to the arrangement of the print image. Therefore, even when the print image and the patch image are arranged on the same side of the paper, the occurrence of flare can be suppressed. Therefore, image correction can be accurately performed based on the color information of the read image read from the patch image.

  For example, in the first embodiment, when the print image is separated from one end of the image formation area by a predetermined distance or more in the main scanning direction, the patch image position determination unit 113 sets the image formation area out of the image formation area. A patch image is arranged on one end side (FIGS. 14 to 16). Therefore, no flare occurs in the patch image.

  In the first embodiment, when the print image is not separated from the one end of the image forming area by a predetermined distance or more in the main scanning direction, the patch image position determination unit 113 further performs the determination based on the color information of the print image. The patch image is arranged at a position where no flare occurs.

  In the first embodiment, when the print image is not separated from one end of the image formation area by a predetermined distance or more in the main scanning direction, the patch image position determination unit 113 selects the image formation area out of the image formation area. The arrangement of the plurality of color patch images is switched so that a color patch image that does not cause flare with respect to the color of the print image is arranged at a position corresponding to the print image at one end side. Therefore, the patch image is arranged at a position where no flare occurs.

  Further, in the first embodiment, the patch image position determination unit 113, when the patch image cannot be arranged on one end side of the image forming area outside the image forming area, and the print image is on the side opposite to one end of the image forming area. When the image is separated from the other end by a predetermined distance or more in the main scanning direction, the patch image is arranged outside the image forming area on the other end side of the image forming area. Therefore, the patch image is arranged at a position where no flare occurs.

  In the first embodiment, the patch image position determination unit 113 divides the patch image into a plurality of color patch images when the patch image cannot be arranged on one end side of the image forming area outside the image forming area. Arranged on one page or a plurality of pages. Therefore, the patch image is arranged at a position where no flare occurs.

  In the first embodiment, the patch image position determination unit 113 divides the patch image into a plurality of color patch images when the patch image cannot be arranged on one end side of the image forming area outside the image forming area. Thus, they are arranged on one end side and the other end side of the image forming area outside the image forming area. Therefore, the patch image is arranged at a position where no flare occurs.

<2. Second Embodiment>
The second embodiment is different from the first embodiment in that when the position of the print image may be changed, the print image is moved to a position where no flare occurs instead of the patch image.

FIG. 17 is a diagram illustrating an example of a print image and a patch image according to the second embodiment.
The distance in the main scanning direction between the yellow data Yd1 and the end of the image forming area ImA (the registration marks T3 and T4 side) is almost zero. Accordingly, in step S23 of FIG. 7, the control device 100 determines that the print image (yellow data Yd1) has a threshold dx ₁ at which the distance from the edge of the image forming area ImA does not cause flare with respect to the patch image Py for yellow. It moves to the position which becomes the above, and it is set as yellow data Yd1 'shown with a dashed-two dotted line. More preferably, the print image is moved to a position that is equal to or higher than the threshold value dx at which no flare occurs with respect to all color patch images Py, Pm, Pc, and Pk.

FIG. 18 is a diagram illustrating an example of a GUI according to the second embodiment.
When the control device 100 moves the print image without permission, the output result of the print image is different from that intended by the user. Therefore, it is desirable to confirm with the user whether the position of the print image may be changed when the user generates a job. As shown in FIG. 18, a job setting screen 130 is prepared. As an example, the message “Yes, can I shift the print image when the print image position is not affected by flare?” ”And“ No ”selection buttons are displayed.

  According to the second embodiment described above, the patch image position determination unit 113 generates a flare to the patch image composition unit 114 (print image moving unit) when the position of the print image may be changed. Indicates the position of the print image that is not to be printed. As a result, the print image is moved away from the patch image, so that no flare occurs in the patch image.

  In addition, by obtaining the user's approval in advance about the movement of the print image on the job setting screen 130, the print image can be moved to a position where no flare occurs after obtaining the user's approval.

<3. Third Embodiment>
The third embodiment will be described by taking a registration mark that is not affected by a print image as a patch image.
A register mark is a patch image formed in addition to a print image in order to perform position adjustment, magnification adjustment, and the like. The data acquired from the registration marks is the formation position and size. Since these pieces of information are not affected by the change in color of several gradations due to the flare, the registration marks T1 to T4 are arranged at predetermined positions regardless of the arrangement of the print image. For example, in FIG. 10, the distance between the registration marks T1 to T4 and the image forming area ImA is extremely short (threshold value dx or less), but the registration marks T1 to T4 are formed at preset positions.

  It should be noted that the present invention is not limited to the above-described embodiments, and various other application examples and modifications can be taken without departing from the gist of the present invention described in the claims. is there.

  For example, the above-described exemplary embodiments are detailed and specific descriptions of the configuration of the apparatus and the system in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described above. . Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment. In addition, the configuration of another embodiment can be added to the configuration of a certain embodiment. Moreover, it is also possible to add, delete, and replace other configurations for a part of the configuration of each exemplary embodiment.

  Each of the above-described configurations, functions, processing units, processing means, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor. Information such as programs, tables, and files for realizing each function can be stored in a recording device such as a memory, a hard disk, or an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

  Further, the control lines and information lines indicate what is considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. Actually, it may be considered that almost all the components are connected to each other.

  Further, in this specification, the processing steps describing time-series processing are not limited to processing performed in time series according to the described order, but are not necessarily performed in time series, either in parallel or individually. The processing (for example, parallel processing or object processing) is also included.

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 10 ... Image forming apparatus main body 13 ... Operation display part 30 ... Image forming part 40 ... Inspection unit 41 ... Inline sensor 100 ... Control apparatus 101 ... Storage device 111 ... Print data acquisition 112: Print image analysis unit, 113 ... Patch image position determination unit, 114 ... Patch image composition unit, 115 ... Patch image position storage unit, 116 ... Read image analysis unit, 117 ... Correction value calculation unit, 118 ... Image correction 130, job setting screen, AP, patch image, Py, yellow patch image, Pm, magenta patch image, Pc, cyan patch image, Pk, black patch image.

Claims (11)

A print image analysis unit that analyzes an arrangement of a print image formed in an image forming area of the paper with respect to the paper;
An image forming apparatus comprising: a patch image position determining unit that determines a position of a patch image for image correction formed outside the image forming region of the sheet based on an analysis result of the print image analyzing unit. The patch image position determination unit determines whether the print image is separated from one end of the image forming area by a predetermined distance or more in the main scanning direction based on the analysis result of the image analysis unit. The image forming apparatus according to claim 1, wherein the patch image is arranged on one end side of the image forming area out of the image forming area when the predetermined distance is away from one end of the forming area. When the printed image is not separated from the one end of the image forming area by the predetermined distance or more in the main scanning direction, the patch image position determining unit further extracts the patch image based on the color information of the printed image. The image forming apparatus according to claim 2, wherein the image forming apparatus is disposed at a position where no flare occurs. The patch image has a plurality of color patch images corresponding to a plurality of basic colors of an image forming unit that forms an image on the paper, and the print image is a predetermined distance from one end of the image forming area in the main scanning direction. If you are not far away,
The patch image position determination unit includes the color patch in which the flare does not occur with respect to the color of the print image at a position corresponding to the print image on one end side of the image formation area out of the image formation area. The image forming apparatus according to claim 3, wherein the arrangement of the plurality of color patch images is changed so that the images are arranged. The patch image position determining unit is configured to dispose the patch image on the one end side of the image forming area out of the image forming area and from the other end opposite to the one end of the image forming area. The image forming apparatus according to claim 3, wherein the patch image is disposed outside the image forming area on the other end side of the image forming area when the distance is greater than or equal to the predetermined distance in the main scanning direction. The patch image position determining unit has a plurality of color patch images corresponding to a plurality of basic colors of an image forming unit that forms an image on the paper, and the patch image is out of the image forming area. The image forming apparatus according to claim 3, wherein when the image cannot be arranged on one end side of the image forming area, the patch image is divided into a plurality of color patch images and arranged on one page or a plurality of pages. The patch image position determination unit divides the patch image into a plurality of the color patch images, and disposes the patch image on one end side and the other end side of the image forming area out of the image forming area. Image forming apparatus. A print image moving unit that changes the position of the print image according to an instruction from the patch image position determining unit,
The patch image position determination unit, when the position of the print image may be changed, instructs the print image moving unit to determine the position of the print image where the flare does not occur. Image forming apparatus. When the printed image is not separated from one end or the other end of the image forming area by a predetermined distance or more, or when the paper has a background color, the patch image position determination unit is configured to apply the patch image to the paper. The image forming apparatus according to claim 3, wherein some or all of the image forming apparatuses are not arranged. A storage unit for storing the position of the patch image determined by the patch image position determination unit;
An image forming unit that forms the print image and the patch image on the paper;
An image reading unit that reads the patch image formed on the paper by the image forming unit;
A read image analysis unit that analyzes color information of a position of the patch image stored in the storage unit from a read image read by the image reading unit;
Based on the analysis result of the read image analysis unit, a correction value calculation unit that calculates a correction value of the print image on the next page and thereafter,
The image forming apparatus according to claim 1, further comprising: an image correction unit that performs image correction based on the correction value calculated by the correction value calculation unit. A procedure for analyzing the arrangement of the print image formed in the image forming area of the paper with respect to the paper;
A procedure for determining a position of a patch image formed outside the image forming area of the paper based on the analysis result;
A program that causes a computer to run.

Images