JP2013148781A - Image forming apparatus, image forming method, and image forming program - Google Patents

Abstract

An object of the present invention is to provide an image forming apparatus, an image forming method, and an image forming program capable of reducing downtime caused by forming an adjustment patch.
A job reception unit that receives a print job, and a deterioration that determines whether or not deterioration occurs in the last print image in the print job every time the print image is formed during the execution period of the print job. When the determination unit determines that the last print image in the print job is deteriorated, the print unit is formed after the print image formed immediately before the determination and the print image formed immediately before. A predetermined image forming unit that forms the predetermined image between the printed image and the print image.
[Selection] Figure 6

Description

  The present invention provides an image forming apparatus that detects a predetermined image formed on an intermediate transfer belt that conveys a print image to a transfer position for transferring a print image onto a recording sheet, and adjusts image formation conditions of the print image based on the detection result. The present invention relates to an image forming method and an image forming program.

  In a conventional electrophotographic image forming apparatus, the density variation of each color image may occur due to a variation in transfer efficiency due to the remaining amount of toner in the developing device and the ambient temperature. In the conventional image forming apparatus, the position of the image of each color may be shifted on the transfer material due to a mechanical attachment error between the photosensitive drums of each color, a change in the optical path length of the laser beam of each color, or the like. .

  2. Description of the Related Art Conventionally, as a technique for adjusting such image quality degradation such as density fluctuation and positional deviation without downtime, a technique for adjusting an image forming condition by forming an adjustment patch between images is known.

  For example, Patent Document 1 discloses that image quality adjustment is simply performed at a paper interval of a print job, thereby maintaining an appropriate image quality without interrupting the print job. Japanese Patent Application Laid-Open No. H10-228688 describes reducing downtime due to adjustment of image forming conditions while maintaining productivity. Patent Document 3 discloses that a test patch is formed at the main scanning end and a configuration for avoiding contamination due to the test patch is provided, and print image formation and image adjustment operation using the test patch are performed in parallel. .

  However, the invention described in Patent Document 1 does not consider how many adjustment patches can be formed in a print job. In the invention described in Patent Document 2, the formation of the adjustment patch is not completed during the print image forming period in the image forming apparatus in which the belt margin cannot be sufficiently secured. Furthermore, in the invention described in Patent Document 3, in the image forming apparatus that cannot sufficiently secure the belt margin in the main scanning direction, the formation of the adjustment patch is not completed during the print image forming period.

  If the formation of the adjustment patch is not completed during the print image formation period, the adjustment patch that is insufficient after the print image formation is formed, resulting in downtime.

  The present invention has been made in view of the above circumstances, and provides an image forming apparatus, an image forming method, and an image forming program capable of reducing downtime caused by forming an adjustment patch. The purpose is to do.

  In order to achieve the above object, the present invention employs the following configuration.

  According to the present invention, an image for detecting a plurality of predetermined images formed on an intermediate transfer belt that conveys a print image to a transfer position to a recording sheet by a detection unit, and adjusting an image forming condition of the print image based on the detection result. A forming apparatus that receives a print job, and determines whether or not the last print image in the print job is deteriorated each time the print image is formed during the execution period of the print job A deterioration determination unit that performs the determination, and if it is determined that deterioration occurs in the last print image in the print job, the print image formed immediately before the determination is performed, and the print image formed immediately before the determination A predetermined image forming unit that forms the predetermined image between the printed image to be formed.

  The present invention detects a plurality of predetermined images formed on an intermediate transfer belt that conveys a print image to a transfer position on a recording sheet by a detection unit, and adjusts image formation conditions of the previous print image based on the detection result An image forming method by a forming apparatus, the job receiving procedure for receiving a print job to the image forming apparatus, and the last print image in the print job each time the print image is formed during the execution period of the print job A deterioration determination procedure for determining whether or not deterioration occurs, a print image formed immediately before the determination is made when it is determined that deterioration occurs in the last print image in the print job, and And a predetermined image forming procedure for forming the predetermined image from a print image formed next to a print image formed immediately before.

  According to the present invention, an image for detecting a plurality of predetermined images formed on an intermediate transfer belt that conveys a print image to a transfer position on a recording sheet by a detection unit, and adjusting an image forming condition of the print image based on the detection result. An image forming program executed in a forming apparatus, the job receiving step for receiving a print job in the image forming apparatus, and a last time in the print job each time the print image is formed during the execution period of the print job. A deterioration determining step for determining whether or not deterioration occurs in the print image, and a print image formed immediately before the determination is made when it is determined that deterioration occurs in the last print image in the print job. And a predetermined image forming step of forming the predetermined image from a print image formed next to the print image formed immediately before

  According to the present invention, the downtime caused by the formation of the adjustment patch is reduced.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to a first embodiment. 1 is a diagram illustrating an example of a hardware configuration of an image forming apparatus according to a first embodiment. It is a figure explaining density adjustment. It is a figure explaining adjustment of an image position. FIG. 2 is a diagram illustrating a functional configuration of the image forming apparatus according to the first embodiment. 3 is a flowchart illustrating the operation of the image forming apparatus according to the first embodiment. It is a figure explaining calculation of the number of adjustment patches which can be formed. It is a figure explaining the effect of a first embodiment. It is a figure explaining the estimation of the image quality by the image quality estimation part of 2nd embodiment. It is a figure explaining the function structure of the image forming apparatus of 3rd embodiment. 10 is a first flowchart illustrating the operation of the image forming apparatus according to the third embodiment. It is a 1st figure explaining the simple adjustment mode in 3rd embodiment. It is a 2nd figure explaining the simple adjustment mode in 3rd embodiment. 12 is a second flowchart illustrating the operation of the image forming apparatus according to the third embodiment.

  In the embodiment of the present invention, during the execution period of one print job, it is determined whether or not deterioration occurs in the last print image in the print job every time a print image is formed. When it is determined that the last print image is deteriorated, an adjustment patch is formed between the print image formed immediately before the determination and the next print image, and the adjustment patch is transferred to the intermediate transfer belt. The image is transferred from the image transfer position to the reading position by the optical sensor.

(First embodiment)
A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a schematic configuration of the image forming apparatus according to the first embodiment.

  The image forming apparatus 100 according to the present embodiment forms toner images for each color of yellow (Y), magenta (M), cyan (C), and black (K), and superimposes them to form a full-color image. A tandem type image forming apparatus was formed.

  The image forming apparatus 100 according to the present embodiment includes a document table 11, a reading device 12, an optical scanning device 13, a photosensitive drum 14 (YMCK), a charging roller 15 (YMCK), and a developing device 16 (YMCK). , Drum cleaning device 17 (YMCK), intermediate transfer belt 18, optical sensor 19, transfer belt cleaning device 20, transfer roller 21, fixing device 22, paper feed roller 23, paper feed tray 24, A paper discharge roller 25 and a paper discharge tray 26 are provided.

  The document table 11 is a table on which a document to be printed, that is, a document to be read is placed. The lower surface of the document table 11 is formed from contact glass. The reading device 12 is a device that reads a document placed on the document table 11 and reads the content of the document by irradiating the document with laser light through a contact glass and receiving reflected light from the document.

  The optical scanning device 13 irradiates the photosensitive drum 14 corresponding to each color with a writing laser beam based on the content of the original read by the reading device 12. The photosensitive drums 14 (14Y, 14M, 14C, and 14K) are drum-shaped image carriers provided for each color of YMCK. The photosensitive drums 14 have the same diameter and are in pressure contact with the intermediate transfer belt 18 at equal intervals.

  A charging device 15, a developing device 16, an intermediate transfer belt 18, a drum cleaning device 17, and a charge eliminating device (not shown) are disposed in the vicinity of the periphery of the photosensitive drum 14 along the drum rotation direction. A laser beam for writing from the optical scanning device 13 is irradiated on the photosensitive drum 14 between the charging device 15 and the developing device 16.

  The charging device 15 (15Y, 15M, 15C, 15K) is a roller-shaped device that is disposed in a non-contact manner on each color photosensitive drum 14, and charges the surface of the photosensitive drum 14. In the image forming apparatus 100, when writing laser light is irradiated from the optical scanning device 13 onto the surface of the photosensitive drum 14 charged by the charging device 15, an electrostatic latent image corresponding to each color is formed on the photosensitive drum 14. It is formed.

  The developing devices 16 (16Y, 16M, 16C, and 16K) are devices that are arranged in such a manner that the developing rollers are in contact with the photosensitive drums 14, and toners (developers) corresponding to the photosensitive drums 14 corresponding to the respective colors. ). At the time of image formation, toner is supplied to the photosensitive drum 14 and the electrostatic latent image formed on the photosensitive drum 14 is developed. The electrostatic latent image becomes a toner image by being developed with toner.

  The drum cleaning device 17 (Y17, M17, C17, K17) is a device that is disposed by bringing a blade (cleaning blade) into contact with each photosensitive drum 14, and is photosensitive after the transfer of the toner image to the intermediate transfer belt 18. Residual toner and paper pieces remaining on the photosensitive drum 14 are removed and collected, and the surface of the photosensitive drum 14 is cleaned. Further, a neutralizing device (not shown) is provided between the drum cleaning device 17 and the charging device 15. The static eliminator neutralizes the surface of the photosensitive drum 14.

  The intermediate transfer belt 18 is an endless belt for sequentially superimposing and transferring the color toner images formed on the surface of the photosensitive drums 14. In the image forming apparatus 100, the toner images of the respective colors are sequentially superimposed to form a full color image on the intermediate transfer belt 14.

  The optical sensor 19 is a device that is disposed in a non-contact manner on the intermediate transfer belt 18 and detects an adjustment patch of the image forming apparatus 10. The optical sensor according to the present embodiment, for example, near both ends in the belt width direction of the intermediate transfer belt 18 and the intermediate transfer belt so as to detect both density adjustment patches and position adjustment patches shown in FIGS. It is preferable to be provided in the vicinity of an intermediate point in the belt width direction.

  The transfer belt cleaning device 20 is a device that is disposed by bringing a blade (cleaning blade) into contact with the intermediate transfer belt 18 and remains on the intermediate transfer belt 18 after the transfer of the toner image to the recording paper to be fed. The remaining toner or toner pattern is removed and collected, and the surface of the intermediate transfer belt 18 is cleaned.

  The transfer roller 21 transfers the color image formed on the intermediate transfer belt 18 onto the recording paper conveyed from the paper feed tray 24. The fixing device 22 heat-fixes the color image transferred on the recording paper to the recording paper. The paper feed roller 23 feeds recording paper. The paper feed tray 24 stores recording paper for each recording paper size. The paper discharge roller 25 discharges the recording sheet on which the color image is thermally fixed to the outside of the image forming apparatus 10. The paper discharge tray 26 is a tray on which the discharged recording paper is placed. The photosensitive drums 14 all rotate in the same direction.

  The intermediate transfer belt 18 moves in a direction opposite to the rotation direction of the photosensitive drum 14, and the transfer roller 21 rotates in a direction opposite to the intermediate transfer belt 18 (the same rotation direction as that of the photosensitive drum 14). . In FIG. 1, the photosensitive drum 14 and the transfer roller 21 rotate counterclockwise, and the intermediate transfer belt 18 rotates clockwise.

  Further, the image forming apparatus 100 according to the present exemplary embodiment is provided with a temperature sensor and a humidity sensor for measuring the environmental temperature (in-machine temperature) and the humidity in the image forming apparatus 100.

  FIG. 2 is a diagram illustrating an example of a hardware configuration of the image forming apparatus according to the first embodiment. The image forming apparatus 100 according to the present embodiment includes a CPU (Central Processing Unit) 110, a ROM (Read Only Memory) 120, a RAM (Random Access Memory) 130, a nonvolatile RAM 140, an I / O control unit 150, and an operation. A panel 160 and an I / F control unit 170 are included.

The CPU 110 expands the program stored in the ROM 120 in the RAM 130, and executes various processes such as data processing and arithmetic processing according to the expanded program.
The ROM 120 is a non-volatile memory, and stores various programs, data, parameters, and the like for the CPU 110 to perform various calculations and controls. The RAM 130 is a memory in which programs and data can be freely written, and provides a working area necessary for the CPU 110 to execute various processes.

  The nonvolatile RAM 140 is a memory for storing adjustment values such as control and timing, registered copy mode settings, and the like. Since the nonvolatile RAM 140 is a nonvolatile memory, the set value is retained even when the image forming apparatus 100 is powered off. The I / O control unit 150 controls the load based on the input from each sensor provided in the image forming apparatus 100. The operation panel 160 receives an operation input from the outside. The I / F control unit 170 receives a print job or an inquiry response to the user from a personal computer or server connected to the image forming apparatus 100 with a cable or the like.

  Next, density adjustment and image position adjustment in the image forming apparatus 100 of the present embodiment will be described with reference to FIGS. In the image forming apparatus 100 of the present embodiment, a predetermined image is formed on the intermediate transfer belt 18, and based on the result of reading this predetermined image by the optical sensor 19, the image forming conditions for image formation are changed.

  In the following description, a predetermined image used for changing the image forming condition is referred to as an adjustment patch. The image forming conditions in the present embodiment include, for example, the value of the developing bias and the output timing of the writing laser beam irradiated from the optical scanning device 13 to the photosensitive drum 14.

  FIG. 3 is a diagram for explaining density adjustment. The image forming apparatus 100 according to the present embodiment forms a density adjustment patch 31 that is a rectangular image with the density varied stepwise along the conveyance direction of the intermediate transfer belt 18. The density adjustment patch 31 may be a patch whose density is increased stepwise in the direction of conveyance of the intermediate transfer belt 18, for example.

  In the present embodiment, six density adjustment patches 31 of yellow, magenta, cyan, and black are formed so as to be shifted in the conveyance direction of the intermediate transfer belt 18 so as not to overlap each other. In this embodiment, by forming the density adjustment patch 31 in this way, adjustment patches having different levels of density for each color can be obtained for each color. The density of each density adjustment patch 31 is controlled by the magnitude of the developing bias when developing the photosensitive drum 14. In the present embodiment, when the density adjustment patch 31 is detected by the optical sensor 19, the characteristics of the density and the control factor are obtained, and the density can be adjusted by changing the control factor so that the target density is obtained.

  Note that the six density adjustment patches 31 of the present embodiment are formed for each color, but the present invention is not limited to this. For example, five density adjustment patches 31 may be formed for each color, or four density adjustment patches 31 may be formed. The number of density adjustment patches 31 formed for each color may be stored in the ROM 120 of the image forming apparatus 100, for example.

  In this embodiment, the density adjustment patch 31 is formed for each color. However, the present invention is not limited to this. For example, only two colors may be formed for the density adjustment patch 31 or only one color may be formed.

  FIG. 4 is a diagram for explaining image position adjustment. The image forming apparatus 100 according to the present embodiment includes a parallel adjustment patch group 32 that is a linear image parallel to the main scanning direction (belt width direction) along the conveyance direction of the intermediate transfer belt 18 and the main scanning direction. The oblique adjustment patch groups 33, which are linear images having an angle of 45 degrees, are alternately formed. In this embodiment, the parallel adjustment patch group 32 and the oblique adjustment patch group 33 are combined into one position adjustment patch. Each parallel adjustment patch group 32 and each oblique adjustment patch group 33 are composed of yellow (Y) patch, magenta (M) patch, cyan (C) patch, and black (K) patch. In this embodiment, eight parallel adjustment patch groups 32 and eight diagonal adjustment patch groups 33 are formed in each of three rows at both ends and the center.

  In the present embodiment, when the parallel adjustment patch group 32 is detected by the optical sensor 19, it is possible to obtain a positional deviation characteristic in the sub-scanning direction, and when the oblique adjustment patch group 33 is detected, the positional deviation characteristic in the main scanning direction is obtained. Can be obtained. In the present embodiment, the positional deviation can be adjusted by changing the timing of laser irradiation from the optical scanning device 13 according to the result.

  In the parallel adjustment patch group 32 and the oblique adjustment patch group 33 of the present embodiment, the shape of each pattern may be stored in the ROM 120 or the like, for example.

  Next, the functional configuration of the image forming apparatus of this embodiment will be described with reference to FIG. FIG. 5 is a diagram illustrating a functional configuration of the image forming apparatus according to the first embodiment. In the present embodiment, the CPU 110 executes a program stored in the ROM 120 or the like, thereby realizing the functions of the following units.

  The CPU 110 of this embodiment includes a job reception unit 111, an adjustment patch number calculation unit 112, an adjustment patch number comparison unit 113, an image quality estimation unit 114, a deterioration determination unit 115, and an adjustment patch formation unit 116.

  The job reception unit 111 according to the present exemplary embodiment receives a print job input to the image forming apparatus 100. The adjustment patch number calculation unit 112 calculates the number of adjustment patches described later. In the following description, when the density adjustment patch 31 and the position adjustment patch are not distinguished, they are simply called adjustment patches. The adjustment patch number comparison unit 113 compares the adjustment patch number calculated by the adjustment patch number calculation unit 112 with the necessary number of adjustment patches.

  The number of adjustment patches required in the present embodiment is the number of adjustment patches required for adjusting the image forming conditions, and may be stored in the ROM 120 or the like in advance. The required number of adjustment patches may be obtained by calculation when the image forming apparatus 100 starts an image forming operation, for example.

  The image quality estimation unit 114 estimates the image quality of the last print image based on the state of the image forming apparatus 100 after the last print image is formed in one print job. Specifically, the image quality estimation unit 114 of the present embodiment calculates estimation data that is used when the deterioration determination unit 115 determines the presence or absence of image quality deterioration. Details of the estimation data will be described later.

  The deterioration determination unit 115 determines whether or not the image quality of the last print image is deteriorated based on the estimated data calculated by the image quality estimation unit 114 and the deterioration determination threshold value stored in the ROM or the like. Details of the processing of the image quality estimation unit 114 and the degradation determination unit 115 will be described later. The adjustment patch forming unit 116 forms an adjustment patch.

  Next, the operation of the image forming apparatus 100 of this embodiment will be described with reference to FIG. FIG. 6 is a flowchart for explaining the operation of the image forming apparatus according to the first embodiment.

  The image forming apparatus 100 according to the present embodiment resets the adjustment execution flag indicating whether or not to adjust the image forming conditions, and does not adjust the image forming conditions (step S601). Next, the image forming apparatus 100 determines whether the job reception unit 111 has received a print job (step S602). If the print job is not accepted in step S602, the image forming apparatus 100 ends the process.

  When a print job is received in step S602, the image forming apparatus 100 acquires the number of remaining print images from the print job (step S603). Subsequently, the image forming apparatus 100 starts up an image forming process and prepares for image formation (step S604). Subsequently, the image forming apparatus 100 forms one print image (step S605). That is, the image forming apparatus 100 forms a print image for one sheet.

  Subsequently, the image forming apparatus 100 counts down one print image from the number of remaining print images acquired in step S603 (step S606). Subsequently, in the image forming apparatus 100, the adjustment patch number calculation unit 112 calculates the number N of adjustment patches that can be formed in the belt empty area during the print image formation period (step S607).

  In this embodiment, the number N of adjustment patches that can be formed in the belt empty area during the print image formation period is the number N1 of adjustment patches that can be formed between print images and the number N2 of adjustment patches that can be formed after the last print image. And the sum. The number N2 of adjustment patches that can be formed after the last printed image in the present embodiment is the number of adjustment patches that can be formed in the belt margin H2. The print image formation period in this embodiment is a period during which a print job is being executed. Specifically, from the start of the formation of the first print image included in the print job to the end of the formation of the last print image. Indicates the period.

  The calculation of the number of adjustment patches that can be formed in the present embodiment will be described below with reference to FIG. FIG. 7 is a diagram illustrating calculation of the number of adjustment patches that can be formed. FIG. 7A is a cross-sectional view illustrating a state in which an adjustment patch is formed between print images and after the last print image is formed, and FIG. 7B is a bird's eye view.

  In the example of FIG. 7, the print image 1 is formed on the paper A1, the print image 2 is formed on the paper A2, and the print image 3 is formed on the paper A3. In FIG. 7, the sheet interval H1 is the distance between sheets determined from the productivity, sheet length, and linear speed during continuous printing, and the belt margin H2 is from the image transfer position P1 to the adjustment patch by the optical sensor 19 from the reading position P2. Is the distance.

  The patch length L is the length of the adjustment patch in the sub-scanning direction, and the paper margin S is the distance from the trailing edge of the printed image on the paper A3 to the trailing edge of the paper. The patch margin W1 is a margin distance for preventing adjustment patches formed between printed images from being transferred to the paper, and the patch interval W2 is a margin distance between adjustment patches when the adjustment patches are continuously formed.

  The various parameters in the present embodiment are values determined by the specifications and design of the image forming apparatus 100, and may be stored in the ROM 120, for example.

First, calculation of the number of adjustment patches that can be formed between printed images in the present embodiment will be described. The adjustment patch number calculation unit 112 of the present embodiment calculates the number of adjustment patches that can be formed between print images by the following equation (1).

Number of adjustment patches N1 = A × (number of remaining print images−1) that can be formed between print images Equation (1)

In the equation (1), A = 1 is satisfied when the sheet interval H1 ≧ patch margin W1 × 2 + patch length L is satisfied, and A = 0 is satisfied when it is not satisfied.

Next, the adjustment patch number calculation unit 112 according to the present embodiment calculates the number of adjustment patches that can be formed after the last print image. The number of adjustment patches that can be formed after the last printed image in the present embodiment is the number of adjustment patches that can be formed in the belt margin H2, and is calculated by the following equation (2).

Number of adjustment patches N2 that can be formed in the belt margin H2
= (Belt margin H2-Paper margin S-Patch margin W1) / (Patch length L + Patch interval W2)
Formula (2)

Next, the adjustment patch number calculation unit 112 of the present embodiment calculates the number N of adjustment patches that can be formed from the calculation results of Expression (1) and Expression (2).

Number of adjustment patches that can be formed N
= Number of adjustment patches N1 that can be formed between printed images + Number of adjustment patches N2 that can be formed in the belt margin H2

In this embodiment, when a plurality of adjustment patches can be formed between print images, the number of adjustment patches that can be formed between print images may be calculated by the following equation (3) instead of equation (1). . However, in the division of equation (3), the decimal point is rounded down.

Number of adjustment patches N1 'that can be formed between printed images
= (Paper interval H1−Patch margin W1 × 2) / (Patch length L + Patch interval W2) × (Number of remaining print images−1) Equation (3)

Returning to FIG. 6, the image forming apparatus 100 determines whether or not the adjustment execution flag is set (step S608). When the adjustment execution flag is set in step S608, the process proceeds to step S614 described later. If the adjustment execution flag is not set in step S608, the image forming apparatus 100 compares the number N of adjustment patches that can be formed by the adjustment patch number comparison unit 113 with the necessary number of adjustment patches (step S609).

  If the number N of adjustment patches that can be formed in step S609 is not less than or equal to the required number of adjustment patches, the image forming apparatus 100 determines whether the image quality is deteriorated by the deterioration determination unit 115 (step S610). Details of step S610 will be described later.

  If it is determined in step S610 that there is no deterioration in image quality, the image forming apparatus 100 determines whether the number of remaining print images is greater than 0 (step S611). If the number of remaining print images is larger than 0 in step S611, the image forming apparatus 100 returns to step S605. If the number of remaining prints is 0 or less in step S611, the image forming apparatus 100 stops the image forming process (step S612) and ends the image forming operation.

  If the number N of adjustment patches that can be formed in step S609 is equal to or less than the necessary number of adjustment patches, the image forming apparatus 100 uses the image quality estimation unit 114 to obtain estimated data for determining whether there is deterioration in the image quality of the last print image. Calculate (step S613). The estimated data is transferred to the deterioration determination unit 115 and used for determination of image quality deterioration in step S610.

  Hereinafter, calculation of estimated data by the image quality estimation unit 114 and determination of deterioration by the deterioration determination unit 115 according to the present embodiment will be described.

  In the present embodiment, for example, deterioration of image quality is determined based on the cumulative number of printed sheets during execution of one print job. In this case, the image quality estimation unit 114 calculates the accumulated number of printed sheets from the number of remaining printed images as estimated data, and stores it in the RAM 130 or the like. The deterioration determination unit 115 reads out and compares the estimated data (cumulative print number) held in the RAM 130 and the deterioration determination threshold stored in the ROM 120 or the like, and determines whether there is deterioration in image quality.

  For example, when the deterioration determination threshold value of the present embodiment is the cumulative number of printed sheets = 100, the deterioration determining unit 115 determines whether or not the estimated data calculated by the image quality estimating unit 114 is 100 sheets or more. Then, the deterioration determining unit 115 determines that the image quality of the last print image is deteriorated when the estimated data calculated by the image quality estimating unit 114 is 100 sheets or more. Further, when the estimated data calculated by the image quality estimating unit 114 is less than 100 sheets, the deterioration determining unit 115 determines that the image quality of the last print image does not deteriorate.

  If it is determined in step 610 that the image quality is deteriorated in the deterioration determining unit 115, the image forming apparatus 100 sets an adjustment execution flag (step S614). Subsequently, the image forming apparatus 100 determines whether or not the number of remaining print images is greater than 0 (step S615). If the number of remaining print images is greater than 0 in step S615, the adjustment patch forming unit 116 forms adjustment patches between the print images (step S616). If the number of remaining printed images is 0 or less in step S615, the adjustment patch forming unit 116 forms an adjustment patch in the belt margin H2 (step S617).

  Subsequently, the image forming apparatus 100 determines whether or not the necessary number of adjustment patches have been formed (step S618). If the formation of the necessary number of adjustment patches has not been completed in step S618, the image forming apparatus 100 proceeds to step S611.

  When the formation of the necessary number of adjustment patches is completed in step S618, the image forming apparatus 100 changes the image forming conditions (step S619). For example, the image forming condition is changed based on the result of the adjustment patch read by the optical sensor 19.

  Subsequently, the image forming apparatus 100 resets the adjustment execution flag (step S620), and proceeds to step S611.

  As described above, in the present embodiment, when the number N of adjustment patches that can be formed in the belt empty area during the print image formation period is equal to the required number of adjustment patches, whether or not image quality deterioration occurs in the last print image. Estimate. In this embodiment, when it is determined that the image quality is deteriorated, the formation of the adjustment patch is started immediately after the formation of the print image formed at the determined time.

  In this embodiment, by starting the formation of the adjustment patch at this timing, the number of adjustment patches necessary for adjusting the image forming conditions can be formed in the belt margin H2. Therefore, according to the present embodiment, it is possible to eliminate the downtime caused by the formation of the adjustment patch.

  The effect of this embodiment will be described below with reference to FIG. FIG. 8 is a diagram for explaining the effect of the first embodiment. FIG. 8A is a diagram showing a comparative example with the present embodiment, and FIG. 8B is a diagram showing a specific example of the operation of the image forming apparatus 100 of the present embodiment.

  In the example of FIG. 8, for example, the paper B1 is the 98th cumulative number of printed sheets, the paper B2 is the 99th cumulative number of printed sheets, the paper B3 is the 100th cumulative number of printed sheets, and the paper B7 is the cumulative number. A 101th sheet was printed. In the example of FIG. 8, it is assumed that 101 print images are formed in one print job. In the example of FIG. 8, the number of adjustment patches that can be formed in the belt margin H2 is three.

  FIG. 8A shows a case where the image quality of the last print image is not estimated. In this case, it is determined that the image quality is deteriorated after the printing of the paper B3. Therefore, the adjustment patch starts to be formed between the print image 3 formed on the paper B3 and the last print image 4 formed on the paper B4. Here, the necessary number of adjustment patches is six. Therefore, in the example of FIG. 8A, only one adjustment patch is formed before the last print image 4 is formed, and five adjustment patches are formed after the last print image 4 is formed.

  Here, since the number of adjustment patches that can be formed in the belt margin H2 is 3, there are two adjustment patches that cannot be formed in the belt margin H2. The time for forming these two adjustment patches is the down time of the image forming apparatus.

  FIG. 8B shows a case where the image quality of the last print image is estimated as described in the present embodiment.

  In this case, immediately after the print image 1 formed on the paper B1 is formed, the adjustment patch number comparison unit 113 determines that the adjustment patch number N is the same as the adjustment patch required number. In the present embodiment, the image quality estimation unit 114 estimates that the cumulative number of printed sheets (estimated data) exceeds the deterioration determination threshold value 100 when the last print image 4 is formed. Therefore, the deterioration determination unit 115 of this embodiment determines that image quality deterioration occurs in the last print image 4.

  Therefore, the image forming apparatus 100 according to the present embodiment starts forming the adjustment patch between the print image 1 formed on the paper B1 and the print image 2 formed on the paper B2 by the adjustment patch forming unit 116.

  In this case, three adjustment patches are formed before the final print image 4 is formed, and three adjustment patches are formed in the belt margin H2. As in the present embodiment, when the image quality is estimated based on the cumulative number of printed sheets, it is preferable that a density adjustment patch is formed as the adjustment patch.

  As described above, in the present embodiment, all the adjustment patches necessary for changing the image forming conditions are formed in the belt empty area during the print image forming period, and no downtime occurs due to the formation of the adjustment patches. Therefore, the occurrence of downtime due to the formation of the adjustment patch can be reduced.

(Second embodiment)
It is a figure explaining 2nd embodiment of this invention with reference to drawings below. The second embodiment of the present invention is different from the first embodiment in that the deterioration determination threshold value is the in-machine temperature of the image forming apparatus. Therefore, in the following description of the second embodiment, only differences from the first embodiment will be described, and those having the same functional configuration as the first embodiment are used in the description of the first embodiment. The same reference numerals as the reference numerals are assigned, and the description thereof is omitted.

  In this embodiment, since the deterioration determination threshold value is the in-machine temperature, the image quality estimation unit 114 calculates the in-machine temperature as estimated data.

  FIG. 9 is a diagram for explaining image quality estimation by the image quality estimation unit of the second embodiment. In the present embodiment, the image forming apparatus 100 includes a temperature sensor for measuring the temperature inside the image forming apparatus 100. In the image forming apparatus 100 of the present embodiment, for example, the history of the temperature inside the machine detected by a temperature sensor is stored in the RAM 130 or the like.

  In this embodiment, every time a print image is formed, the temperature inside the image forming apparatus 100 is detected and stored in the RAM 130.

  In the present embodiment, the image quality estimation unit 114 creates an approximate expression from the in-machine temperature history and the cumulative number of printed sheets, and calculates the estimated in-machine temperature immediately after the last print image formation as estimated data. The approximate expression is, for example, a linear approximate expression.

  In the example of FIG. 9, the image quality estimation unit 114 calculates, as estimated data, the estimated in-machine temperature T after forming the 100th sheet as the last print image, based on the approximate expression obtained from the in-machine temperature history. Stored in the RAM 130.

  If the estimated data (estimated in-machine temperature T) is higher than the deterioration determination threshold value stored in the ROM 120 or the like, the deterioration determination unit 115 determines that the last print image has image quality deterioration. Note that the in-machine temperature that is the deterioration determination threshold of the present embodiment may be the in-machine temperature when the previous image forming condition is changed, for example. Since the processing after it is determined that the image quality is deteriorated is the same as that in the first embodiment, the description thereof is omitted.

  In the present embodiment, when the history of the in-machine temperature is retained, the in-machine temperature at the time of cumulative printing for the past five sheets may also be retained. In this case, the image quality estimation unit 114 may calculate an estimated data by creating an approximate expression from the cumulative number of printed sheets based on the current time and the in-machine temperature for the past five sheets.

  As described above, in the present embodiment, for example, the image quality of the last print image may be estimated based on a change in the temperature inside the apparatus, and the presence or absence of image quality deterioration may be determined.

  Further, when the image quality is estimated based on the in-machine temperature as in the present embodiment, it is preferable to use a position adjustment patch as the adjustment patch.

(Third embodiment)
It is a figure explaining 3rd embodiment of this invention with reference to drawings below. The third embodiment of the present invention is different from the first embodiment in that it has a simple mode when forming an adjustment patch. Therefore, in the following description of the third embodiment, only differences from the first embodiment will be described, and those having the same functional configuration as the first embodiment are used in the description of the first embodiment. The same reference numerals as the reference numerals are assigned, and the description thereof is omitted.

  FIG. 10 is a diagram illustrating a functional configuration of the image forming apparatus according to the third embodiment. The CPU 110A according to the present embodiment includes a simple adjustment mode setting unit 117 and a simple adjustment mode execution unit 118 in addition to the units included in the CPU 110 according to the first embodiment.

  The simple adjustment mode setting unit 117 of the present embodiment sets whether to execute the simple adjustment mode. Specifically, the simple adjustment mode setting unit 117 according to the present embodiment is configured when the number N of adjustment patches that can be formed during the print image formation period is smaller than the necessary number of adjustment patches, that is, during the print image formation period (within the belt margin H2). ) Is set to execute the simple adjustment mode when all necessary adjustment patches cannot be formed.

  The simple adjustment mode of the present embodiment is a mode in which, for example, the number of adjustment patches to be formed and the pattern are changed to reduce the time taken to form the adjustment patches.

  The simple adjustment mode execution unit 118 executes formation of an adjustment patch in the simple adjustment mode based on an instruction to execute the simple adjustment mode. Specifically, the simple adjustment mode execution unit 118 instructs the adjustment patch forming unit 116 to form an adjustment patch for the simple adjustment mode. Details of the adjustment patch for the simple adjustment mode will be described later.

  As described above, in the present embodiment, even when the necessary number of adjustment patches cannot be formed in the belt margin H2, for example, the downtime caused by the formation of the adjustment patch can be reduced by executing the simple adjustment mode.

  The operation of the image forming apparatus 100 of this embodiment will be described below with reference to FIG. FIG. 11 is a first flowchart illustrating the operation of the image forming apparatus according to the third embodiment.

  The processing from step S1101 to step S1114 in FIG. 11 is the same as the processing from step S601 to step S614 in FIG.

  When the adjustment execution flag is set in step S1114, the adjustment patch number comparison unit 113 determines whether or not the number N of adjustment patches that can be formed during the print image formation period is smaller than the necessary number of adjustment patches (step S1115). ). If the number N of adjustment patches is smaller than the necessary number of adjustment patches in step S1115, the simple adjustment mode setting unit 117 does not perform the simple adjustment mode and does not set the simple adjustment mode (step S1116).

  If the number N of adjustment patches is greater than or equal to the required number of adjustment patches in step S1115, the simple adjustment mode setting unit 117 executes the simple adjustment mode and sets the simple adjustment mode (step S1117).

  Subsequently, the image forming apparatus 100 determines whether or not the number of remaining printed images is greater than 0 (step S1118).

  If the number of remaining print images is larger than 0 in step S1118, the simple adjustment mode execution unit 118 causes the adjustment patch forming unit 116 to form adjustment patches for the simple adjustment mode between the print images (step S1119). If the number of remaining print images is 0 or less in step S1118, the simple adjustment mode execution unit 118 causes the adjustment patch forming unit 116 to form an adjustment patch for the simple adjustment mode in the belt margin H2 (step S1120).

  The processing from step S1121 to step S1123 is the same as the processing from step S618 to step S620 in FIG.

  The adjustment patch for the simple adjustment mode of the present embodiment will be described below with reference to FIGS.

  FIG. 12 is a first diagram illustrating the simple adjustment mode in the third embodiment. FIG. 12 shows a case where the density adjustment patch 31 is formed as the adjustment patch.

  In the present embodiment, when the simple adjustment mode is executed when the density adjustment patch 31 is used, the density level of the density adjustment patch 31 for each color is reduced. That is, in this embodiment, the number of adjustment patches to be formed is reduced.

  In the example of FIG. 12, the density level of the density adjustment patch 31 is reduced from 6 levels to 3 levels.

  When instructed to form the density adjustment patch 31 for the simple adjustment mode, the adjustment patch forming unit 116 of the present embodiment changes the magnitude of the developing bias when developing the photosensitive drum 14, and the density adjustment patch 31. Change the concentration.

  Specifically, the adjustment patch forming unit 116 applies a developing bias obtained by adding or subtracting a predetermined voltage set in advance to the developing bias at that time to the photosensitive drum 14. In the example of FIG. 12, for example, the current development bias is set to 300V and the specified value is set to 20V. In this case, the developing bias is applied to the photosensitive drum 14 in the order of 300 V, 320 V, and 280 V, and the three-stage density adjustment patch 31 having a density corresponding to each developing bias is formed.

  In the present embodiment, if the image forming condition is changed to the developing bias corresponding to the density adjustment patch having the density closest to the preset density target value among the formed density adjustment patches 31, the image quality can be simplified. Adjustment (density adjustment) can be performed. In the example of FIG. 12, when the developing bias is 320V, a density adjustment patch whose density is closest to the target value is formed. Therefore, the image forming apparatus 100 can easily adjust the density if the developing bias is set to 320 V as an image forming condition for forming the next print image.

  In the present embodiment, the number of density adjustment patches 31 formed in the simple adjustment mode is three, but the present invention is not limited to this. The number of density adjustment patches 31 formed in the simple adjustment mode may be set in advance, for example. In this embodiment, for example, when the simple adjustment mode is set, the adjustment patch number calculation unit 112 calculates again the number N of adjustment patches that can be formed during the print image formation period, and the calculated number is used in the simple adjustment mode. The number of density adjustment patches 31 to be formed may be used.

  FIG. 13 is a second diagram illustrating the simple adjustment mode in the third embodiment. FIG. 13 shows a case where a position adjustment patch is formed as the adjustment patch. FIG. 13A shows a case where the pattern of the position adjustment patch is changed, and FIG. 13B shows a case where the pattern of the position adjustment patch is changed and the number is further reduced.

  In the present embodiment, when the simple adjustment mode is executed when the position adjustment patch is used, only one of the parallel adjustment patch group 32 and the oblique adjustment patch group 33 is formed. That is, in the present embodiment, the pattern of the position adjustment patch to be formed is changed.

  In the example of FIG. 13A, an example is shown in which only the parallel adjustment patch group 32 of the parallel adjustment patch group 32 and the oblique adjustment patch group 33 is formed, but the present invention is not limited to this. In the present embodiment, only the oblique adjustment patch group 33 may be formed.

  In the present embodiment, not only one of the parallel adjustment patch group 32 and the oblique adjustment patch group 33 is formed, but the number of parallel adjustment patch groups 32 or oblique adjustment patch groups 33 to be further formed may be reduced. .

  The example of FIG. 13B shows an example in which the three parallel adjustment patch groups 32 formed in the belt width direction of the intermediate transfer belt 18 are reduced to one near the middle of the intermediate transfer belt 18. In the example of FIG. 13B, the parallel adjustment patch group 32 to be formed is one near the middle, but the present invention is not limited to this. In the present embodiment, two parallel adjustment patch groups 32 may be formed at both ends of the intermediate transfer belt 18.

  As described above, in the present embodiment, when the simple adjustment mode is executed, the time required for forming the adjustment patch can be reduced by reducing the number of adjustment patches to be formed or changing the pattern to an omitted pattern. Therefore, in this embodiment, it is possible to reduce the downtime caused by the formation of the adjustment patch.

  In the present exemplary embodiment, normal image quality may be performed in a print job after simple image quality adjustment in the simple adjustment mode. The operation will be described below with reference to FIG.

  FIG. 14 is a second flowchart for explaining the operation of the image forming apparatus of the third embodiment.

  The processing from step S1401 to step S1422 in FIG. 14 is the same as the processing from step S1101 to step S1122 in FIG.

  When the image forming condition is changed in step S1422, the image forming apparatus 100 determines whether or not the simple adjustment mode is set (step S1423). If the simple adjustment mode is not set in step S1423, the process proceeds to step S1411. If the simple adjustment mode is set in step S1423, the image forming apparatus 100 cancels the setting of the simple adjustment mode (step S1424).

  In the example of FIG. 14, in order to cancel the setting of the simple adjustment mode by executing step S1424, the next time the job reception unit 111 receives a print job, the normal image quality adjustment is performed. The normal image quality adjustment is to adjust the image quality by forming the same number of adjustment patches as necessary.

  In each of the above embodiments, whether to use the density adjustment patch 31 or the position adjustment patch may be selected by setting.

  As mentioned above, although this invention has been demonstrated based on each embodiment, this invention is not limited to the requirements shown in the said embodiment. With respect to these points, the gist of the present invention can be changed without departing from the scope of the present invention, and can be appropriately determined according to the application form.

100 Image forming apparatus 110 CPU
111 Job reception unit 112 Adjustment patch number calculation unit 113 Adjustment patch number comparison unit 114 Image quality estimation unit 115 Degradation determination unit 116 Adjustment patch formation unit 117 Simple adjustment mode setting unit 118 Simple adjustment mode execution unit

JP 2010-210941 A JP 2009-229958 A JP 2006-194963 A

Claims (10)

An image forming apparatus that detects a plurality of predetermined images formed on an intermediate transfer belt that conveys a print image to a transfer position on a recording sheet by a detection unit and adjusts image formation conditions of the print image based on the detection result. And
A job reception unit for receiving print jobs;
A degradation determination unit that determines whether degradation occurs in the last print image in the print job every time the print image is formed during the execution period of the print job;
When it is determined that the last print image in the print job is degraded, a print image formed immediately before the determination is performed, and a print image formed next to the print image formed immediately before And a predetermined image forming unit that forms the predetermined image from between. An estimation unit that calculates estimation data used to determine whether or not deterioration occurs in the last printed image;
The degradation determination unit
The image forming apparatus according to claim 1, wherein a determination is made as to whether or not deterioration occurs in the last print image based on the estimated data and a deterioration determination threshold value stored in advance in a storage unit. A calculation unit that calculates the number of the predetermined images that can be formed on the intermediate transfer belt during the execution period of the print job;
A comparison unit that compares the number of the predetermined images with a required number of the predetermined images set in advance,
The estimation unit calculates the estimation data when the number of the predetermined images is equal to the required number,
The image forming apparatus according to claim 2, wherein the deterioration determination unit determines whether deterioration occurs in the last print image based on the estimated data. The calculation unit includes:
The number of the predetermined images that can be formed between the print images during the print job execution period;
Calculating the number of the predetermined images that can be formed between the transfer position on the intermediate transfer belt and the reading position by the detection unit;
The sum of the number of the predetermined images that can be formed between the print images and the number of the predetermined images that can be formed between the transfer position and the reading position is placed on the intermediate transfer belt during the execution of the print job. The image forming apparatus according to claim 3, wherein the number of the predetermined images that can be formed is set. The estimated data is
The cumulative number of prints calculated from the number of print images during the print job execution period;
The image forming apparatus according to claim 2, wherein the deterioration determination threshold is a predetermined cumulative number of printed sheets. The estimated data is
An estimated in-machine temperature calculated from a history of the in-machine temperature of the image forming apparatus during the print job execution period;
The image forming apparatus according to claim 2, wherein the deterioration determination threshold is a predetermined internal temperature.   7. A simple adjustment mode execution unit for executing a simple adjustment mode for changing the number of the predetermined images to be smaller than the preset required number or changing the pattern of the predetermined images. The image forming apparatus described in the item. The simple adjustment mode execution unit includes:
The image forming apparatus according to claim 7, wherein the simple adjustment mode is executed when the number of the predetermined images that can be formed between the print images during the print job execution period is smaller than the necessary number. An image formed by an image forming apparatus that detects a plurality of predetermined images formed on an intermediate transfer belt that conveys a printed image to a transfer position on a recording sheet by a detection unit and adjusts image forming conditions of the printed image based on the detection result. A forming method comprising:
In the image forming apparatus,
A job acceptance procedure for accepting print jobs;
A deterioration determination procedure for determining whether deterioration occurs in the last print image in the print job each time the print image is formed during the execution period of the print job;
When it is determined that the last print image in the print job is degraded, a print image formed immediately before the determination is performed, and a print image formed next to the print image formed immediately before And a predetermined image forming procedure for forming the predetermined image from between. Executed in an image forming apparatus that detects a plurality of predetermined images formed on an intermediate transfer belt that conveys a print image to a transfer position on a recording sheet by a detection unit and adjusts image formation conditions of the print image based on the detection result An image forming program,
In the image forming apparatus,
A job reception step for receiving a print job;
A deterioration determination step of determining whether or not deterioration occurs in the last print image in the print job every time the print image is formed during the execution period of the print job;
When it is determined that the last print image in the print job is degraded, a print image formed immediately before the determination is performed, and a print image formed next to the print image formed immediately before And a predetermined image forming step for forming the predetermined image from between.

Images