JP5168651B2 - Image forming apparatus, image forming system, and post-processing apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus, an image forming system, and a post-processing apparatus.

In an image forming apparatus such as a copying machine or a printer, a latent image is formed on a photoreceptor based on image data, the latent image is converted into a toner image by a developing unit, and the toner image is transferred to a recording medium by a transfer unit. An image is formed on a recording medium by fixing with a fixing unit.
In this type of image forming apparatus, abnormal images such as white spots and streaks may occur due to transfer defects. Such an abnormal image is confirmed by the user checking the image formed on the recording medium discharged to the paper discharge tray one by one. For this reason, an image forming apparatus in the production printing field that continuously prints a large number of sheets requires a great amount of labor for such a check. For this reason, an image forming apparatus is required to have a function of automatically checking whether an output image is good or bad and selecting and excluding the defective image.

  Japanese Patent Application Laid-Open No. H10-228561 describes a device in which a printed matter inspection control device is installed as a post-processing device of an image forming apparatus. The printed matter inspection control apparatus acquires document image data from a network, and records based on document image data and inspection image data read from an image formed on a recording medium based on the document image data by the image forming apparatus. Determine the quality of the image on the medium. Then, based on the determination result, the non-defective printed matter and the defective printed matter are separated and discharged. Therefore, since the printed matter discharged to the discharge portion where the non-defective printed matter is discharged has a good quality image, it is not necessary for the user to check the image quality by checking one by one. Thereby, a user's load reduction, a check mistake, etc. can be eliminated. Therefore, the satisfaction of the printer can be improved in the image forming apparatus in the production printing field. In addition, since the possibility that a defective image is mixed with the output product is reduced, it is possible to improve the satisfaction of the client side who orders the business from the printing company.

JP 2005-205797 A

However, since the document image data is data stored in a personal computer or the like, the inspection image data is data obtained by the image detection means arranged in the printed matter inspection control apparatus. Is different. Therefore, it is necessary to convert the document image data into a format that can be compared with the inspection image data. As a result, when printing several tens of pages of document image data, a considerable amount of time is required for such conversion processing. Therefore, there is a problem that it takes time before the printed matter inspection can be started.
Further, in a professional-use image forming apparatus, an operator may adjust an apparatus manually to adjust an output image by looking at a printed matter. As a result, the output image determined by the operator to adjust the apparatus to be a non-defective product does not match the original image data. For this reason, when the printed matter inspection control device of Patent Document 1 is used in the subsequent stage of the professional use specification image forming apparatus, an output image that the operator has determined to be non-defective is determined to be defective. Therefore, the image quality determination that the user wants to obtain cannot be performed as a non-defective product, and the image determination that meets the user's request cannot be performed.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus and an image that can quickly start image quality determination and can perform image quality determination in accordance with a user's request. A forming system and an aftertreatment device are provided.

In order to achieve the above object, the invention of claim 1 is directed to image forming means for forming an image on a recording medium based on image data, image detecting means for detecting an image on the recording medium, and the image forming means. The image detection unit detects an image formed on the recording medium, acquires image data for inspection, and based on the image data for inspection, the image quality of the image on the recording medium formed by the image formation unit In an image forming apparatus including an image quality determination unit that performs determination, reference image data acquisition that detects a non-defective image formed on a recording medium by the image detection unit and acquires reference image data serving as a reference for image quality determination Control means for executing a mode, and based on the reference image data and the inspection image data, perform image quality determination of an image on a recording medium formed by the image forming means. As it is characterized in that constitute the image quality determination unit.
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect of the present invention, the image forming apparatus further includes a paper feeding unit that conveys the recording medium to the image forming unit, and the recording medium on which the good image is formed is supplied from the paper feeding unit Thus, the image detecting means is configured to detect.
According to a third aspect of the present invention, in the image forming apparatus of the first aspect, a dedicated supply unit is provided for supplying the recording medium on which the non-defective image is formed to the image detecting means. It is.
According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, a regular recording medium discharge unit that discharges a recording medium on which an image determined to be a normal image by the image quality determination unit is discharged. And an abnormal recording medium discharge unit for discharging a recording medium on which an image determined to be an abnormal image by the image quality determination unit is discharged, and a recording medium being conveyed based on the determination result of the image quality determination unit. And switching means for switching between discharging to the regular recording medium discharging section or discharging to the abnormal recording medium discharging section.
According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, a test pattern is formed on the recording medium and detected by a test pattern detecting unit that detects the test pattern on the recording medium. The image forming apparatus includes an image forming condition adjusting unit that adjusts an image forming condition based on the detection result, and a dedicated recording medium storage unit that stores a dedicated recording medium on which the test pattern is formed. .
According to a sixth aspect of the present invention, there is provided an image forming apparatus according to the fifth aspect, wherein the dedicated recording medium on which the test pattern after passing the test pattern detecting means is formed is stored in the dedicated recording medium storing unit. The formation condition adjusting means is configured.
According to a seventh aspect of the present invention, in the image forming apparatus of the sixth aspect, the test pattern detecting means is arranged in the dedicated recording medium storage unit.
According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the fifth to seventh aspects, access prohibiting means for prohibiting access to the dedicated recording medium in the dedicated recording medium storage unit is provided. It is what.
According to a ninth aspect of the present invention, in the image forming apparatus according to any of the fifth to seventh aspects, the dedicated recording medium storage unit can be replaced with a paper feeding unit for storing a normal recording medium. Is.
According to a tenth aspect of the present invention, an image forming apparatus including an image forming unit that forms an image on a recording medium based on image data, and a post-processing of the recording medium on which the image is formed by the image forming apparatus. In an image forming system including a processing device, an image detection unit that detects an image on a recording medium, and a reference that is a reference for image quality determination by detecting a non-defective image formed on the recording medium by the image detection unit A control unit that executes a reference image data acquisition mode for acquiring image data; an image on a recording medium formed by the image forming apparatus is detected by the image detection unit; Image quality determination means for determining the image quality of an image on a recording medium formed by the image forming apparatus based on the data and the inspection image data. That.
According to an eleventh aspect of the present invention, in the image forming system according to the tenth aspect, the image processing unit is provided in the post-processing apparatus, and a recording medium on which the non-defective image is formed is supplied to the image detecting unit. The post-processing apparatus is provided with a dedicated supply section for the purpose.
According to a twelfth aspect of the present invention, in the image forming system according to the eleventh aspect, the post-processing apparatus is provided with a control unit that executes the reference image data acquisition mode.
According to a thirteenth aspect of the present invention, in the image forming system according to any one of the tenth to twelfth aspects, the post-processing apparatus ejects a recording medium on which an image determined to be a normal image by the image quality determination unit is recorded. A normal recording medium discharge unit, an abnormal recording medium discharge unit from which a recording medium on which an image determined to be an abnormal image is recorded by the image quality determination unit, and a determination result of the image quality determination unit are conveyed. And a switching means for switching whether to discharge the recording medium to the regular recording medium discharge section or the abnormal recording medium discharge section.
According to a fourteenth aspect of the present invention, there is provided a post-processing apparatus that performs post-processing of a recording medium on which an image is formed by the image forming apparatus, an image detecting unit that detects an image on the recording medium, and a recording medium that includes the image detecting unit. A control means for detecting a non-defective image formed on the top and executing a reference image data acquisition mode for acquiring reference image data as a reference for image quality determination; and an image on a recording medium formed by the image forming apparatus. Image quality that is detected by the image detection means, acquires image data for inspection, and performs image quality determination of an image on a recording medium formed by the image forming apparatus based on the reference image data and the image data for inspection And a judging means.

According to the present invention, a non-defective image formed on a recording medium is detected by an image detection unit, and reference image data serving as a reference for image quality determination is acquired, so that the data format of the reference image data and the inspection image data is changed. Can be the same. Therefore, as described in Patent Document 1, there is no need to convert the reference image data into a format that can be compared with the inspection image data. As a result, it is possible to complete the preparation for image quality determination only by causing the image detection means to detect a non-defective image formed on the recording medium. Therefore, compared to Patent Document 1, it is possible to shorten the time until image quality determination can be started.
Furthermore, since the non-defective image formed on the recording medium is detected by the image detecting means and the reference image data serving as a reference for image quality determination is acquired, the following effects can be obtained. In other words, if the image formed on the recording medium determined by the user to adjust the device is detected as a non-defective product by the image detecting means, the image determined by the user to be determined as non-defective by adjusting the device is used as the reference image data. Can be used. As a result, it is possible to perform image quality determination with the image quality desired by the user as a non-defective product, and it is possible to obtain an effect that image quality determination can be performed in accordance with the user's request.

[Embodiment 1]
Hereinafter, as an image forming apparatus to which the present invention is applied, an embodiment of a tandem type color laser copying machine (hereinafter simply referred to as “copying machine”) in which a plurality of photoconductors are arranged in parallel will be described.
FIG. 1 is a schematic configuration diagram of a copying machine according to the present embodiment.
The copier includes a printer unit 100, a paper feeding unit 200, a scanner 300, and the like. An automatic document feeder 400 fixed on the scanner 300 is also provided.

  The printer unit 100 as image forming means includes four sets of process cartridges 18Y, 18M, 18C, and 18K for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K). An image forming unit 20 and an intermediate transfer unit 17 serving as transfer means. Y, M, C, and K added after the numerals are the members for yellow, cyan, magenta, and black (the same applies hereinafter).

  An optical writing unit 21 is provided above the image forming unit 20. The optical writing unit 21 includes a light source (not shown), a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates the surface of a photoreceptor to be described later with laser light based on image data.

Hereinafter, the yellow process cartridge 18 will be described.
The process cartridge 18Y includes a drum-shaped photoreceptor 1Y, a charger 2Y, a developing device 4Y, a drum cleaning device 5Y, a static eliminator 6Y, and the like.
The surface of the photoreceptor 1Y is uniformly charged by the charger 2Y as a charging means. The surface of the photoreceptor 1 </ b> Y that has been subjected to charging processing is irradiated with laser light Ly that has been modulated and deflected by the optical writing unit 21. Then, the potential of the irradiation part (exposure part) is attenuated. By this attenuation, an electrostatic latent image for Y is formed on the surface of the photoreceptor 1Y. The formed electrostatic latent image for Y is developed by the developing device 4Y as developing means to become a Y toner image.
The Y toner image formed on the Y photoreceptor 1Y is primarily transferred to an intermediate transfer belt 63 described later. The surface of the photoreceptor 1Y after the primary transfer is cleaned of the transfer residual toner by the drum cleaning device 5Y.
In the Y process cartridge 18Y, the photoreceptor 1Y cleaned by the drum cleaning device 5Y is neutralized by a neutralizer 6Y such as a quenching lamp. Then, it is uniformly charged by the charger 2Y and returns to the initial state. The series of processes as described above is the same for the other process cartridges 18M, 18C, and 18K.

Next, the intermediate transfer unit 17 will be described.
The intermediate transfer unit 17 includes an intermediate transfer belt 63, a belt cleaning device 90, and the like. Further, the tension roller 14, the driving roller 15, the secondary transfer backup roller 16, the four primary transfer bias rollers 62 </ b> Y, 62 </ b> M, 62 </ b> C, 62 </ b> K, the secondary transfer roller 23, and the like are also provided.
The intermediate transfer belt 63 is tensioned by a plurality of rollers including the stretching roller 14. Then, it is endlessly moved clockwise in the drawing by the rotation of the driving roller 15 driven by a belt driving motor (not shown).
The four primary transfer bias rollers 62Y, 62M, 62C, and 62K are disposed so as to be in contact with the inner peripheral surface side of the intermediate transfer belt 63, respectively, and receive a primary transfer bias from a power source (not shown). Further, the intermediate transfer belt 63 is pressed toward the photoreceptors 1Y, 1M, 1C, and 1K from the inner peripheral surface side to form primary transfer nips. In each primary transfer nip, a primary transfer electric field is formed between the photoreceptor 1 and the primary transfer bias roller 62 due to the influence of the primary transfer bias.
The above-described Y toner image formed on the Y photoconductor 1Y is primarily transferred onto the intermediate transfer belt 63 due to the influence of the primary transfer electric field and nip pressure. On the Y toner image, the M, C, and K toner images formed on the M, C, and K photoconductors 1M, 1C, and 1K are sequentially superimposed and primarily transferred. By this primary transfer of superposition, a four-color superposed toner image (hereinafter referred to as a four-color toner image), which is a multiple toner image, is formed on the intermediate transfer belt 63.

  The secondary transfer roller 23 is in contact with the front surface of the belt to form a secondary transfer nip. A secondary transfer bias is applied to the secondary transfer roller 23 by a secondary transfer power source (not shown). On the other hand, the secondary transfer backup roller 16 is grounded. As a result, a secondary transfer electric field is formed between the secondary transfer backup roller 16 and the secondary transfer roller 23. The four-color toner image formed on the front surface of the intermediate transfer belt 63 enters the secondary transfer nip as the intermediate transfer belt 63 moves endlessly. Then, it is secondarily transferred to a transfer sheet (not shown) as a recording medium. Transfer residual toner remaining on the surface of the intermediate transfer belt 63 after passing through the secondary transfer nip is cleaned by a belt cleaning device 90 that sandwiches the belt with the driving roller 15 on the left side in the drawing.

  In the sheet feeding device 200, a plurality of two-stage sheet feeding cassettes 44a and 44b capable of accommodating a plurality of transfer sheets stacked in a bundle of sheets are disposed in the sheet feeding device 200 so as to overlap in the vertical direction. Each of the paper feed cassettes 44a and 44b presses the paper feed rollers 42a and 42b against the uppermost transfer paper of the paper bundle. Then, by rotating the paper feed rollers 42 a and 42 b, the uppermost transfer paper is sent out toward the paper feed path 46.

  A paper feed path 46 for receiving transfer paper fed from the paper feed cassettes 44a and 44b, which are paper feed units, has a plurality of transport roller pairs 47 and a pair of registration rollers 49 provided near the ends in the paths. ing. Then, the transfer paper is conveyed toward the registration roller pair 49. The transfer sheet conveyed toward the registration roller pair 49 is sandwiched between the rollers of the registration roller pair 49. On the other hand, in the intermediate transfer unit 17, the four-color toner image formed on the intermediate transfer belt 63 enters the secondary transfer nip as the belt moves endlessly. The registration roller pair 49 sends out the transfer paper sandwiched between the rollers at a timing at which the transfer paper can be brought into close contact with the four-color toner image at the secondary transfer nip. Thereby, in the secondary transfer nip, the four-color toner image on the intermediate transfer belt 63 is in close contact with the transfer paper. Then, it is secondarily transferred onto the transfer paper and becomes a full color image on the white transfer paper. The transfer paper on which the full-color image is formed in this manner is sent to the fixing device 25 after leaving the secondary transfer nip.

  The fixing device 25 includes a fixing roller 26 and a pressure roller 27 that is pressed toward the fixing roller 26. The fixing roller 26 and the pressure roller 27 are in contact with each other to form a fixing nip, and the transfer paper is sandwiched therebetween. The fixing roller 26 has a heat source (not shown) inside, and heats the fixing roller 26 by heat generated from the heat source. The heated fixing roller 26 heats the transfer paper sandwiched in the fixing nip. The full color image is fixed on the transfer paper by the influence of the heating and the nip pressure.

  Below the fixing device 25, a switchback portion 85 and a reverse path 86 are disposed. When the transfer paper discharged from the fixing device 25 reaches the conveyance path switching position by the swingable first switching claw 87, the paper discharge path 89 or the switchback unit according to the rocking stop position of the switching claw 87. Sent to 85. When the paper is sent toward the paper discharge path 89, the paper is conveyed by a plurality of paper discharge roller pairs 84 and discharged to the outside of the apparatus, and then on the first paper discharge tray 81 or the second paper discharge tray 82. Stacked.

  On the other hand, when the paper is sent toward the switchback unit 85, the reverse roller pair 85a provided in the switchback unit 85 rotates in the reverse direction and the reverse switching claw 85b swings, so that the transfer sheet is switched back. The signal is sent from the unit 85 to the reverse path 86. In this way, after being turned upside down by the switchback portion 85, it is conveyed toward the registration roller pair 49 again. Then, it enters the secondary transfer nip again, and a full-color image is formed on the other side.

  When copying a document (not shown), for example, a bundle of sheet documents is set on a document table (not shown) of the automatic document feeder 400. However, when the original is a single-sided original closed in a main form, it is set on a contact glass (not shown). Prior to this setting, the automatic document feeder 400 is opened with respect to the copying machine main body, and the contact glass (not shown) of the scanner 300 is exposed. Thereafter, the single-bound original is pressed by the closed automatic document feeder 400.

  After the original is set in this way, when a copy start switch provided on an operation panel (not shown) is pressed, the original reading operation by the scanner 300 is started. However, when a sheet document is set on the automatic document feeder 400, the automatic document feeder 400 automatically moves the sheet document to a contact glass (not shown) prior to the document reading operation.

  In parallel with such document reading operation, each device in each process cartridge 18Y, 18M, 18C, 18K, the intermediate transfer unit 17, and the fixing device 25 start driving. Then, based on the image data constructed by the scanner 300, the optical writing unit 21 is driven and controlled, and Y, M, C, and K toner images are formed on the photoreceptors 1Y, 1M, 1C, and 1K. The These toner images become four-color toner images superimposed and transferred on the intermediate transfer belt 63.

  Further, almost simultaneously with the start of the document reading operation, the paper feeding operation is started in the paper feeding device 200. In this paper feeding operation, one of the paper feeding rollers 42 is selectively rotated, and the transfer paper is sent out from one of the paper feeding cassettes 44. The fed transfer sheets are separated one by one by the separation roller 45 and enter the reverse feeding path 46, and then conveyed toward the secondary transfer nip by the conveyance roller pair 47.

  In the case of forming another color image composed of two or more toners, the copying machine stretches the intermediate transfer belt 63 so that the upper stretched surface thereof is substantially horizontal, and all the upper stretched surface is placed on the upper stretched surface. Photoconductors 1Y, 1M, 1C, and 1K. On the other hand, when forming a monochrome image consisting of only K toner, the intermediate transfer belt 63 is tilted to the lower left in the drawing by a mechanism (not shown) and the upper stretched surface is set to Y, M, C. The photoconductors 1Y, 1M, and 1C are separated. Of the four photoconductors 1Y, 1M, 1C, and 1K, only the K photoconductor 1K is rotated counterclockwise in the drawing to form only the K toner image. At this time, for Y, M, and C, not only the photosensitive member 1 but also the developing device is stopped to prevent unnecessary consumption of the photosensitive member and the developer.

  A manual feed tray 43 is disposed on the right side of the copying machine in the drawing, and the transfer paper on the manual feed tray 43 is fed to the registration roller pair 49.

  In the present embodiment, an image detection sensor unit 91 that is an image detection unit that detects an image on a transfer sheet after fixing is provided in the vicinity of the fixing device 25. As the image detection sensor unit 91, an image sensor such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) is arranged in a straight line in the width direction of the transfer paper, and can detect image information two-dimensionally. It is.

This copier is a professional-use copier that is mainly used by printers. In such copiers, the main task is to output dozens to hundreds or thousands of the same image output. Become a task. Conventionally, it has been necessary to visually check the image quality of the output product of this task, which has been a heavy burden on the operator. For this reason, this copying machine is provided with a function (image quality judging means) for automatically checking for image defects (scratches / missing images, hues, color shifts, etc.), thereby reducing the burden on the operator.
The copying machine determines the image quality of the image on the transfer paper after fixing based on the detection result of the image detection sensor unit 91 serving as image detection means. As a result of the determination, the transfer paper on which the image determined to be defective is formed is discharged to the first paper discharge tray 81 which is an abnormal recording medium discharge portion, and an image determined to be a normal image is formed. The transfer paper is discharged to the second paper discharge tray 82 which is a regular recording medium discharge portion. Specifically, when the image quality determination unit determines that the image is defective, the second switching claw 83 serving as a switching unit is swung to switch to a path for discharging the transfer sheet to the first sheet discharge tray 81. On the other hand, when the image quality determination means determines that the image is normal, the second switching claw 83 is swung to switch to a path for discharging the transfer sheet to the second sheet discharge tray 82.

  A paper discharge path 89 from the image detection sensor unit 91 to the second switching claw 83 is meandered so as to be longer than the length of the maximum paper size that can be used by the copying machine in the transfer paper conveyance direction. With this configuration, it is possible to prevent the leading edge of the transfer paper from reaching the second switching claw 83 before the image detection sensor unit 91 finishes detecting the trailing edge of the transfer paper. That is, the image detection sensor unit 91 detects the image to the trailing edge of the transfer paper, determines the image quality, controls the second switching claw 83 based on the determination result, and then moves the leading edge of the transfer paper to the second switching claw 83. Can be reached. Accordingly, the transfer paper on which the defective image is formed can be reliably discharged to the first paper discharge tray 81. In FIG. 1, the meandering direction of the paper discharge path 89 is drawn downward. However, the present invention is not limited to this configuration, and if the distance of the paper discharge path 89 can be taken as much as necessary for function, even if meandering upward, Folding conveyance in the direction or linear conveyance long in the horizontal direction may be performed.

FIG. 2 is a diagram schematically showing a control unit of the copying machine.
As shown in the figure, the control unit as control means is composed of a main control board 101 and a board in charge of various functions. Connected to the main control board 101 are a printer board 105 which is a communication means for performing data communication with a PC (personal computer) 106 which is an external device, and a writing board 104 which controls the writing unit 21 based on image data. ing. The main control board 101 is also connected with an operation panel 102 and a scanner 300 as operation display means. A drive device (not shown) that drives the image detection sensor unit 91 and the first switching claw 87, a drive device (not shown) that drives the second switching claw 83, and the like are connected to the main control board 101 via the I / O board 103. It is connected to the.
The main control board 101 includes a CPU (Central Processing Unit) serving as computing means, a memory (RAM (Random Access Memory)) serving as data storing means, a ROM (Read Only Memory), and various processing circuits and computing circuits.

  The route through which image data (hereinafter referred to as input image data) transmitted from the PC 106 or the scanner 300 is transmitted to the writing board 104 is determined by the design of the electronic circuit board, but usually via the main control board 101. There is no route. Specifically, input image data transmitted from the PC 106 is received by the printer board 105 and transmitted to the writing board 104. Further, the input image data constructed by the scanner 300 is transmitted to the writing board 104. This is because the input image data is heavy information and does not need to be passed through the main control board 101 in particular. Of course, a configuration may be adopted in which input image data is transmitted to the writing board 104 via the main control board 101. Further, a configuration in which a third board (not shown) is relayed and transmitted to the writing board 104 may be employed.

  Image data corresponding to the image on the transfer paper input from the image detection sensor unit 91 is input to the main control board 101 via the I / O board 103. Alternatively, it is input to the main control board 101 via a dedicated analog data processing circuit board (not shown).

In the copying machine of the present embodiment, the output image is checked as a pre-process for forming hundreds or thousands of continuous images. Specifically, first, one image that is a continuous image is output as a sample image. The user visually checks whether or not a desired color is obtained from the sample image. At this time, for example, if the user determines that the red color is insufficient, the operation panel or PC is operated to adjust the copying machine so that the red color is increased. After the adjustment, the sample image is output again. When the sample image has the image quality requested by the user (hereinafter referred to as a non-defective image), the transfer paper on which the sample image is formed is set on the manual feed tray 43. When the transfer paper on which the non-defective image is formed is set on the manual feed tray 43, the reference image data acquisition mode is started from the operation panel 102 or the PC 106. When the main control board 101 receives the start instruction signal, the drive paper for driving the manual feed roller 43a is controlled via the I / O board 103 to transfer the transfer paper set on the manual feed tray 43a. Transport. Then, after passing through the secondary transfer nip and the fixing device 25 and reaching the image detection sensor unit 91, the non-defective image on the transfer paper is detected by the image detection sensor unit 91. Image data detected in this way (hereinafter referred to as reference image data) is input to the main control board 101 via the I / O board 103. The reference image data input to the main control board 101 is stored in a memory on the main control board 101 or a memory on its peripheral board. The reference image data may be stored in the memory as it is, or the feature amount (tone value for each area) of the reference image data used for image quality determination described later is extracted and stored in the memory to reduce the information amount. In the above, it may be stored in a memory. Then, the transfer paper on which the non-defective image is formed is discharged to a predetermined discharge destination.
The above is the preprocessing for performing continuous image formation.

  When such preprocessing is completed, continuous image formation is performed while image quality determination is performed. When an image is formed on the transfer paper and the transfer paper on which the image is formed reaches the image detection sensor unit 91, an image formed on the transfer paper (hereinafter referred to as an output image) is detected and detected image data ( (Hereinafter referred to as inspection image data) is input to the main control board via the I / O board 103. Then, the image quality of the output image is determined based on the inspection image data input to the main control board 101 and the reference image data stored in the memory.

The image quality determination of the output image is performed as follows.
The image quality determination is performed by extracting the feature amount of the inspection image data and the feature amount of the reference image data stored in the memory, and comparing the feature amount of the inspection image data with the feature amount of the reference image data by the comparison operation circuit. To do. Specifically, the reference image data is read from the memory in synchronization with the inspection image data input to the main control board 101, and passes through a processing circuit for feature amount extraction. Thereafter, the reference image data is compared with the inspection image data by the comparison operation circuit. Note that if the reference image data is converted into a feature amount when it is stored, the feature amount extraction process after reading is not performed. The processing for extracting the feature amount and the comparison operation as described above are described on the assumption that a hardware circuit is used. This is because the amount of information in the image data is large and it is difficult to process with software in terms of time. If processing in software becomes possible in the future, processing in software may be performed. As described above, in this embodiment, the image quality determination means is constructed by the CPU on the main control board, the memory and processing circuit in the peripheral portion, and the comparison operation circuit.

Next, extraction of feature amounts of the reference image data and the inspection image data will be specifically described.
FIG. 3 is a diagram schematically illustrating feature amount extraction.
As shown in the figure, the image data is divided into a plurality of areas, and feature amounts for each area are extracted. In the present embodiment, the color tone (R, G, B signal) for each area is extracted as the feature amount. The feature amount for each area of the reference image data and the inspection image data is extracted by calculating color tone values (R, G, B signals) for each area from the image data detected by the image detection sensor unit 91. The As shown in FIG. 3, when the area is divided, a feature amount of 5 × 14 is extracted.

Next, image quality determination will be described.
The image quality determination of this embodiment is performed as follows.
The color tone value of the reference image data of the area extracted by the method as described above is compared with the color tone value of the inspection image data. If there is a large deviation, it is determined that an image abnormality has occurred in the area. ing.
For example, if white is expressed as R = G = B = 100 and black is expressed as R = G = B = 0 as values representing the color tone, for example, in a certain area, the reference image data When the tone values are R = 100, G = 100, and B = 100, the output image corresponding to this area should be blank. However, if the inspection image data corresponding to this area has a tone value such as R = 80, G = 20, and B = 5, and the output image corresponding to this area is a reddish image, On the other hand, it can be seen that any color is generated in the output image, and it can be estimated that a transfer failure occurs in a specific color. Further, if the inspection image data corresponding to this area has a tone value such as R = 0, G = 0, and B = 0, a defect such as a stain has occurred at a position corresponding to this area of the output image. Can be recognized.
In this way, it is possible to determine whether or not an image abnormality has occurred by dividing an image into areas (particularly effective when divided into minute areas) and comparing the color development (hue) in those areas.

Further, as shown in FIG. 4, by dividing the area further finely, it is possible to detect an abnormal image such as a vertical stripe.
In the case of a monochrome character image as shown in FIG. 4, the color tone value of the area covered by the non-defective image character image detected by the image detection sensor unit 91 is, for example, R = G = B = 50. (This indicates that black occupies half of the area. That is, in the case of a monochrome image, this tone value can be rephrased as the K toner density.) Basically, R = G = B. Further, the area where no character is applied is the color of the transfer paper itself. When the color of the transfer paper is white, the reference image data is R = G = B = 100. On the other hand, for example, when a vertical streak as shown in FIG. 4 occurs, the inspection image data in the streaked area is, for example, the reference image data R = G = B = 50 ( R = G = B = 30 (black occupies 70% of the area). From this difference, it is possible to detect the occurrence of image defects such as streaks. If such a phenomenon occurs only in the character peripheral portion, it can be determined that the image quality is deteriorated because the character is fat or crushed. Further, if a certain density is continuously detected in an area where there is no character, it can be recognized that a streak has occurred. Further, if the color stripe is not a black stripe, the influence of the R, G, B balance is lost, and the occurrence of the color stripe can be recognized.

  Further, when the image data for detection is R = G = B = 100 with respect to the area where the tone value of the reference image data is R = G = B = 50 (black occupies half of the area), the output image It can be recognized that white spots have occurred at a location corresponding to that area.

  As described above, in the present embodiment, the image quality is determined by comparing the feature amount (tone value for each area) of the reference image data with the feature amount (tone value for each area) of the inspection image data. It is possible to determine image quality deterioration such as streaks, character thickening, crushing, and omission in the output image, and abnormal hue, and to perform abnormal image determination with high accuracy.

  As a result of the image quality determination regarding the image on the transfer paper in this way, when it is determined that there is an abnormality such as an image defect, a hue, a density, and a stripe, the main control board 101 passes through the I / O board 103 to A driving device (not shown) that drives the 2 switching claw 83 is controlled to switch to a path for discharging the transfer paper to the first paper discharge tray 81. As a result, the transfer paper on which the abnormal image is formed is discharged to a first paper discharge tray 81 different from the second paper discharge tray 82 from which the transfer paper on which a normal image is formed is discharged. Therefore, it is not necessary for the user to confirm the image quality by viewing one image at a time, and the load on the user can be reduced.

In the present embodiment, the reference image data serving as a reference for determining the image quality of the output image is data obtained by detecting a non-defective image by the image detection sensor unit 91 that detects the output image. Therefore, it is possible to make a determination by comparing the data when the output image is detected (inspection image data) with the reference image data as they are, and the arithmetic processing at the time of image quality determination can be performed without load. .
Furthermore, the reference image data serving as a reference for determining the image quality of the output image is data obtained by the image detection sensor unit 91 detecting a non-defective image adjusted to the image quality obtained by the user in the preprocessing. Therefore, the output image determined to be a non-defective image has the image quality desired by the user. As a result, it is possible to perform image determination in accordance with the user's request.

  Next, a modification of the first embodiment will be described.

[Modification 1]
FIG. 5 is a schematic configuration diagram of the copying machine according to the first modification.
In the above, the transfer paper on which the non-defective image is formed is supplied from the manual feed tray 43 as a paper feed unit and is detected by the image detection sensor unit 91. A non-defective image supply tray 111 is provided as a dedicated supply unit for supplying the transfer paper on which the non-defective image is formed to the image detection sensor unit 91.
The non-defective image supply tray 111 is provided above the second paper discharge tray 82. The image detection sensor unit 91 is further downstream in the transfer sheet conveyance direction than the merging point between the path through which the transfer sheet that has passed through the fixing device 25 passes and the path through which the transfer sheet fed from the non-defective image supply tray 111 passes. Is provided.
The transfer paper on which the non-defective image set on the non-defective image supply tray 111 is formed reaches the image detection sensor unit 91 without passing through the secondary transfer nip or the fixing device. As a result, there is no possibility of deteriorating a non-defective image due to toner contamination at the secondary transfer portion or heat from the fixing device 25, and the reliability as the reference image data can be maintained. In addition, when a transfer sheet on which a non-defective image is formed is fed from the manual feed tray 43, special control such as control for prohibiting the image forming operation is required to distinguish it from a normal image forming operation. However, by providing a dedicated paper feed tray so that the transfer paper on which the non-defective image is formed does not pass through the secondary transfer nip or the fixing device 25, the image forming operation is prohibited when the reference image data acquisition mode is executed. There is no need to perform control.

  In addition, when a transfer sheet on which a non-defective image is formed is fed from the manual feed tray 43, it is necessary for the user to specify whether to perform a normal image forming operation or a reference image data acquisition mode by an operation. However, by providing the non-defective image supply tray 111, when the transfer paper is set on the non-defective image supply tray 111, only the reference image data acquisition mode can be executed, so the reference image data acquisition mode is automatically executed. It is also possible. As a result, it is possible to suppress work effort and mistakes in procedure.

  If the non-defective image supply tray 111 cannot be installed on the discharge tray side due to the configuration of the image forming apparatus, it may be provided on the manual feed tray side. In this case, the transfer paper on which the non-defective image set on the non-defective image supply tray 111 is formed cannot reach the image detection sensor unit 91 without passing through the secondary transfer nip or the fixing device 43. However, by providing the non-defective image supply tray 111, it is possible to automatically execute the reference image data acquisition mode.

[Modification 2]
FIG. 6 is a schematic configuration diagram of a copying machine according to a second modification.
In the copying machine of the second modification, a test pattern detection sensor unit 92 which is a test pattern detection means for detecting a test pattern on a transfer sheet is provided in the vicinity of the image detection sensor unit 91. Further, a test transfer paper storage unit which is a dedicated recording medium storage unit in which a dedicated transfer paper (hereinafter referred to as a test transfer paper) on which only a test pattern is formed is stored between the reversing path 86 and the switchback unit 85. 115 is disposed.

The copying machine according to the second modification outputs a test pattern periodically or at an arbitrary timing, and this test pattern is detected by the test pattern detection sensor unit 92. Based on the detection result, the fixing temperature, the developing bias, the charging An image quality adjustment mode for adjusting image forming conditions such as bias is executed.
For example, it may be automatically executed immediately after the main switch is turned on or at a constant operation time interval or a constant print sheet interval.

  When the image adjustment mode is executed, the test transfer paper is transported from the test transfer paper storage unit 115 to the sheet feeding path, and a predetermined test pattern is formed on the test transfer paper. The test transfer paper on which the test pattern is formed passes through the fixing device 25 and then reaches the test pattern detection sensor unit 92. The test pattern detection sensor unit 92 detects the test pattern formed on the test transfer paper, and the image forming conditions such as the fixing temperature, the developing bias, and the charging bias are adjusted based on the detection result.

FIG. 7 is a schematic perspective view of the test pattern detection sensor unit 92.
As shown in the figure, in the test pattern detection sensor unit 92, three-point optical sensors 92b are attached to the sensor substrate 92a at equal intervals in the transfer paper width direction. In addition, a counter roller 93 is disposed at a position facing the optical sensor 92b in order to stabilize the posture of the transfer paper at the detection position. Further, any configuration other than the facing roller may be used as long as it can stabilize the posture of the transfer sheet being conveyed at the detection position. For example, a mechanism for adsorbing and transferring the transfer paper onto the transfer belt, or a configuration in which a guide member is provided on the back side of the transfer paper being transferred and the rollers hold the transfer paper upstream and downstream of the sensor may be used. Absent.

Although a reflective optical sensor is used as the optical sensor 92b, a transmissive optical sensor may be used in some cases. When a reflection type optical sensor is used, the arrangement of optical elements in the sensor varies depending on the type of image characteristic measured from the test pattern. For example, when detecting the image density and color from the test pattern, it is arranged as “45 deg light projection, 0 deg light reception” used in a commercially available colorimeter or the like, and configured to detect diffuse reflection light. Further, when detecting the glossiness of an image from a test pattern, it is arranged as “60 deg light projection, 60 deg light reception” to detect regular reflection light. The arrangement of the optical elements in the optical sensor is not limited to these.
In FIG. 7, three optical sensors 92b are provided. However, any number of optical sensors 92b may be used depending on the configuration of the test pattern formed on the transfer paper. Further, instead of using a plurality of monocular optical sensors 92b as shown in this figure, a configuration using a line sensor such as a CIS (Contact Image Sensor) may be used. The image detection sensor unit 91 may also be used as the test pattern detection sensor unit 92.

  In FIG. 6, the test pattern detection sensor unit 92 for detecting the test pattern on the transfer paper is arranged immediately after the fixing device 25, but the test pattern detection sensor unit 92 is arranged on the reverse path 86. May be. Further, it is preferable to detect a test pattern after fixing. This is because by detecting the test pattern after fixing, it is possible to detect the image characteristics on the transfer paper after fixing, which are finally seen by the user. As a result, it is possible to perform image quality adjustment with higher accuracy than that in which image characteristics (such as toner adhesion amount) obtained from an unfixed test pattern in the middle of image formation are detected and image quality adjustment is performed. .

  If the test pattern detection sensor unit 92 is disposed in the reversing path 86, the test pattern is detected by the test pattern detection sensor unit 92, and then the transfer paper on which the test pattern is formed passes through the secondary transfer unit and the fixing device 25 again. There is a demerit that it is necessary to make it happen. However, there is an advantage that the test pattern detection sensor unit 92 is easy to install because there is more space around the reverse path than immediately after the fixing device 25. Note that the test pattern detection sensor unit 92 is not limited to this, and may be anywhere as long as it can detect the transfer paper after the test pattern is formed.

  The test transfer paper stored in the test transfer paper storage unit 115 is replenished by a service person during regular maintenance of the apparatus. Also, if the type of test transfer paper to be supplied is determined to be one type, the background state at the time of test pattern formation does not change, so that high-precision image quality adjustment can be performed.

  In the copying machine of the second modification, a dedicated storage unit for storing the test transfer paper used in the image actual adjustment mode is provided, and the transfer paper therein is regularly supplied by a service person who visits for maintenance. . Therefore, it is possible to avoid the use of the transfer paper which is the property of the user for forming the test pattern when the image quality adjustment mode is executed. Thereby, user dissatisfaction can be removed.

  Further, as shown in FIG. 8, the test transfer paper on which the test pattern is formed may be returned to the test transfer paper storage unit 115 and reused. As shown in the figure, the switchback portion 85 is provided with a test switching claw 85c, and the test transfer paper conveyed to the path toward the switchback portion 85 by the first switching claw 87 is the test switching claw 85c. It is conveyed to the test transfer paper storage unit 115 by the claw 85c. Thereby, the test transfer paper on which the test pattern is formed can be returned to the test transfer paper storage unit 115.

Further, as shown in FIG. 8, a test pattern detection sensor unit 92 may be provided in the test transfer paper storage unit 115. In this case, the test pattern detection sensor unit 92 is provided in the vicinity of the carry-in portion into which the test transfer paper is carried (the left end portion in the figure of the test transfer paper storage unit 115).
In addition, a plurality of test transfer papers are stored in the test transfer paper storage unit, but the test transfer paper is configured to be exposed at the place where the test pattern detection sensor unit 92 is disposed, The test transfer paper in the test transfer paper storage unit prevents detection. In this way, if the test pattern detection sensor unit 92 is installed in the test transfer paper storage unit, in order to make a copier capable of executing the image quality adjustment mode, only the test transfer paper storage unit is used as the copier. Add to Therefore, it is not necessary to install additional small parts separately. As a result, it becomes easy to handle as an optional unit, and the load of additional work that occurs when the user selects it as an optional unit can be reduced.

In the copying machine shown in FIG. 8, the test transfer paper is reused by performing the following control.
First, a test pattern is formed on a test transfer sheet on which no test pattern is formed, and after executing the image quality adjustment mode, the control unit sets the count value to 1. When the next image quality adjustment mode is executed, the count value is referred to. When the count value is 1, control is performed so that a test pattern is formed in a blank portion downstream of the test transfer paper in the sheet conveyance direction. Then, after executing the image quality adjustment mode, the count value is incremented by one. In this way, when the image quality adjustment mode is executed and the count value exceeds the predetermined value, and there is no margin for forming a test pattern on the front surface of the test transfer paper, the test paper is transferred from the transfer paper storage unit 115 to the test. The transfer paper is conveyed from the left side in the figure, and the test transfer paper is reversed through the reversing path 86 so that a test pattern is formed on the back surface of the test transfer paper. Thereafter, the test transfer paper is transported from the test transfer paper storage unit 115 from the right side in the figure, and a test pattern is formed in the margin on the back surface of the test transfer paper. If the count value exceeds the predetermined value and there is no margin for the test pattern to be formed on the back side of the test transfer paper after execution of the image quality adjustment mode, the count value is reset, and after the image quality adjustment mode, the test transfer Paper is discharged to the paper output tray. At this time, by transferring the test transfer paper to the first paper discharge tray 81 from which the transfer paper on which the defective image is formed is not taken out, the transfer paper on which the test pattern is drawn is transferred from the transfer paper on which the non-defective image is formed. You can save time and effort. In addition, a test transfer paper discarding unit for storing a test transfer paper on which a test pattern can no longer be formed may be provided in the apparatus. When a service person who regularly visits maintenance supplies test transfer paper, the test transfer paper discarded in the test transfer paper disposal unit is collected. Accordingly, it is possible to reduce the time and effort for the user to discard the test transfer paper on which the test pattern can no longer be formed, which is preferable. Alternatively, the test transfer paper on which the test pattern can no longer be formed may be collected in the test transfer paper storage unit 115. In this case, the bottom plate on which the test transfer paper that can be used in the image quality adjustment mode is stacked is configured to be movable up and down. When returning the reusable test transfer paper to the test transfer paper storage unit 115, the bottom plate is lowered and returned to the test transfer paper loaded on the bottom plate. On the other hand, when returning the test transfer paper on which the test pattern can no longer be formed to the transfer paper storage unit 115, the bottom plate is raised and collected under the bottom plate.

In this copying machine, the secondary transfer roller 23, the fixing device 25, the switchback unit 85, and the reversing path 86 are unitized as a transport unit so that the jam processing can be easily performed. It can be pulled out. The transport unit can be pulled out by moving a lever (not shown) after opening a front door (not shown). As described above, it is preferable that both the secondary transfer roller 23 and the fixing device 25 can pull out the switchback portion 85 and the reversing path 86 because it is easy to work when removing jammed paper. In such a configuration, it is preferable to provide a test transfer paper storage unit 115 disposed between the switchback portion 85 and the reversing path 86 in the transport unit because the device configuration is not complicated. However, if the test transfer paper storage unit 115 is configured to be able to be pulled out from the apparatus main body, for example, the test transfer paper storage unit 115 has the same configuration as the paper feed cassettes 44a and 44b, and the upper part is opened. In the case of the configuration, the test transfer paper may be exposed to the outside of the apparatus and accessed to the test transfer paper in the test transfer paper storage unit. If the user accesses the test transfer paper storage unit and replaces the transfer paper, the type of transfer paper used for the test may change, making it impossible to perform high-quality image adjustment. There is.
Therefore, the upper open portion of the test transfer paper storage unit 115 is covered with a cover member or the like, and the cover member is fixed to the test transfer paper storage unit 115 with a screw. As a result, general users cannot easily access the inside of the test transfer paper storage unit. In addition, if it is difficult to understand the position of the screw, the user finds the screw and removes the cover member to access the test transfer paper in the test transfer paper storage unit, unless there is much need. There is nothing. If you do not want the user to touch it, attach a warning text to the copier, transport unit, lid member, etc., or use a special screw to fasten the lid member to the test transfer paper storage unit 115. It is only necessary to prevent the screw from being removed unless it is a special tool.

  Further, considering the workability when removing jammed paper, it may be preferable to adopt a configuration in which the test transfer paper storage unit 115 can be easily removed. In this case, the test transfer paper storage unit 115 can be easily detached from the transport unit using only the lever.

  Further, the structure of the transport unit may cover the test transfer paper storage unit so that the test transfer paper in the test transfer paper storage unit 115 cannot be accessed. In this case, the test transfer paper storage unit 115 is screwed to the transport unit, but the position of the screw is difficult to understand, or the transfer paper storage unit 115 is screwed to the transport unit using a special screw. Thus, the test transfer paper storage unit 115 may be difficult to be removed from the transport unit.

  In this way, the test transfer paper storage unit in the test transfer paper storage unit can be accommodated by avoiding access to the inside of the test transfer paper storage unit with an access prohibition means such as screwing or affixing a warning text. It will be possible to manage the state properly. This makes it easier to manage test transfer paper, including repeated use of a single transfer paper, and can reliably fix the type of test transfer paper, so that a stable image quality adjustment mode is executed. can do.

Further, as shown in FIG. 9, the apparatus may be configured such that the normal transfer cassette 44a can be replaced with a test transfer sheet storage unit 115.
As shown in FIG. 9, in this copying machine, the test transfer paper storage unit 115 has substantially the same configuration as the normal paper feed cassette 44a. The test transfer paper storage unit 115 is supported by a slide rail for supporting the paper feed cassette 44a so that it can be pulled out. In addition, the copying machine is provided with a test conveyance path connected to the upper paper feed cassette storage section among the two stages of paper feed cassette storage sections in the paper discharge path. In addition, a switching claw 116 is provided for switching the path through which the transfer paper is transported between the test transport path and the paper discharge path 89. When the test transfer paper is discharged as it is without being reused, the test conveyance path and the switching claw are not necessary. In FIG. 9, the test pattern detection sensor unit 92 is arranged in the vicinity of the fixing device. However, as shown in FIG. 8, the test pattern detection sensor unit 92 is arranged in the test transfer paper storage unit 115. May be.

  The copying machine is provided with a pickup roller for feeding the transfer paper in the paper feed cassette. The test transfer paper storage unit 115 is used for the test in the test transfer paper storage unit as described above. The transfer paper must be configured so that the user cannot easily access it. For this reason, the test transfer paper storage unit 115 is covered with a lid member so that the test transfer paper storage unit 115 is closed. For this reason, the pickup roller cannot be used for transporting the test transfer paper in the test transfer paper storage unit. For this reason, it is necessary to provide a paper feed mechanism in the test transfer paper storage unit. Needless to say, a hole may be formed in the test transfer paper storage unit 115 so that the pickup roller 42a can be used so that the pickup roller 42a contacts the test transfer paper.

  Usually, a paper cassette installed in a copying machine often has a configuration in which about 500 sheets of plain paper can be stacked. Therefore, in the test transfer paper storage unit 115 that only needs to be able to accommodate a small number of sheets, if the configuration is the same as that of the paper feed cassette, the test transfer paper storage unit 115 is considerably too large to be accommodated. However, considering that the transfer paper that has been used once is stored in the test transfer paper storage unit and then fed again, the test transfer paper storage unit has a little space. Is good. This is because if the space inside the unit is too narrow, there is a high possibility that a jam will occur when the transfer paper is carried into the unit. Further, as described above, when a paper feed mechanism is provided inside the unit, a space in the thickness direction is necessary.

  In this way, when the test transfer paper storage unit 115 can be replaced with the paper feed cassette 44a, there is a demerit that the paper feed stage is collapsed by one stage. This is an effective means when the paper storage unit 115 cannot be installed. With this configuration, a user who attaches more importance to the stability of the image quality can be provided as an option by crushing one stage of the paper feed cassette, referred to as an image quality stabilization unit (recording medium storage unit).

[Embodiment 2]
Next, Embodiment 2 will be described.
FIG. 10 is a schematic configuration diagram of an image forming system.
As shown in the figure, this image forming system includes a copying machine and a post-processing device 110. The post-processing device 110 includes an image detection sensor unit 91, a non-defective image supply tray 111 for feeding transfer paper on which a non-defective image is formed, and a first discharge tray for discharging the transfer paper on which the image is formed. 81, a second paper discharge tray 82, and the like.

First, as in the first embodiment, this image forming system also checks the output image as a pre-process for forming hundreds or thousands of continuous images. First, an image for performing a continuous image is output as a sample image, and the copying machine is adjusted so that the sample image has a desired image quality. Then, the transfer paper on which the sample image (non-defective image) having a desired image quality is formed is set on the non-defective image supply tray 111. When the transfer paper on which the non-defective image is formed is set on the non-defective image supply tray 111, an operation panel (not shown) provided in the post-processing device 110 is operated to start the reference image data acquisition mode. When the reference image data acquisition mode is started, the transfer paper on which the non-defective image set on the non-defective image supply tray 111 is formed by the post-processing device 110 is conveyed to the image detection sensor unit 91. The image detection sensor unit 91 detects a non-defective image and acquires reference image data used as a reference for image quality determination.
In this image forming system, preparation for image quality determination can be performed only by the post-processing apparatus 110, and the copying machine does not have to have an extra control mode.

  When the above pre-processing is completed, hundreds or thousands of continuous images are formed while performing image quality determination. An image is formed by the copying machine, and the transfer paper discharged from the copying machine is carried into the post-processing apparatus 110. The image of the transfer paper carried into the post-processing device 110 is detected by the image detection sensor unit 91. Then, when it is determined that the image is abnormal as compared with the reference image data, the second switching claw 83 swings and the transfer paper is discharged to the first paper discharge tray 81.

  This image quality determination operation may be performed by the control unit of the copying machine or by the post-processing apparatus 110. When the determination is made by the control unit of the copying machine, the reference image data acquired by executing the reference image data acquisition mode is sent from the post-processing apparatus 110 to the copying machine, and the copying machine transmits the reference transmitted from the post-processing apparatus 110. Save image data in memory. The image quality determination at the time of continuous image formation is performed by transmitting the inspection image data obtained by detecting the output image by the post-processing device 110 to the copying machine, the reference image data stored in the memory by the copying machine, and the inspection image data. The image quality of the output image is determined by comparing with the image data. When the output image is a non-defective product, a control signal is transmitted from the copying machine to the post-processing device 110 so that the transfer paper is conveyed to the second paper discharge tray 82. If the output image is defective, a control signal is transmitted from the copying machine to the post-processing device 110 so that the transfer paper is conveyed to the first paper discharge tray 81.

  When the image quality determination operation is performed by the post-processing device 110, the post-processing device 110 is provided with image quality determination means (CPU, memory for storing reference image data, processing circuit, comparison operation circuit). The reference image data acquired by executing the reference image data acquisition mode is stored in a memory included in the post-processing device 110. The processing circuit provided in the post-processing device 110 extracts the feature amount of the inspection image data and the feature amount of the reference image data obtained by detecting the output image by the post-processing device, and the comparison operation circuit provided in the post-processing device 110 The image quality determination is performed by comparing the extracted feature amounts.

  As described above, by providing the post-processing device 110 with the image quality determination means, the image quality determination operation can be performed by the post-processing device 110 alone. This eliminates the need to prepare an operation mode for image quality determination on the image forming apparatus main body side. Further, by making it possible to implement the reference image reading operation mode by the post-processing device 110 alone, all preparations and actual operations for image quality determination can be performed on the post-processing device side. By adopting such a configuration, for example, even in an old copier or printer that does not support the image quality determination operation, as long as the post-processing device 110 can be connected, the function of the post-processing device alone Thus, an image quality determination operation can be performed. Further, not only image forming apparatuses such as old-type copying machines and printers, but also image forming apparatuses that are not equipped with any operation mode related to image quality determination, the image quality determination operation is performed by connecting the post-processing device 110. It can be carried out. That is, an image quality determination operation can be easily added to any image forming apparatus, which is a great advantage for the user.

  Further, the post-processing device 110 shown in FIG. 10 does not describe a configuration for performing sorting, stapling, bookbinding, etc., which the normal post-processing device 110 has, but these components are of course the back-end. It may be included in the processing device 110.

  The above-described image forming apparatus is a full color machine of a quadruple tandem type intermediate transfer system, but may be a full color machine such as a quadruple tandem type direct transfer system or a single drum type intermediate transfer system. Further, a monochrome machine such as a one-drum type direct transfer system may be used. In the above description, the electrophotographic image forming apparatus has been described. However, an ink jet type image forming apparatus may be used. In the image forming apparatus, the toner image is electrostatically transferred onto the transfer paper. However, the toner image may be thermally transferred onto the transfer paper.

As described above, according to the image forming apparatus of the present embodiment, the reference image data acquired by detecting the non-defective image formed on the transfer paper by the image detection sensor unit, and the output on the transfer paper by the image detection sensor unit during continuous image formation. The image quality is determined based on the image data for inspection acquired by detecting the image. Thus, the format of the reference image data can be made the same as the format of the inspection image data, and there is no need to convert the reference image data into a format that can be compared with the inspection image data. Therefore, it is possible to shorten the time until image quality determination can be started.
Furthermore, an image formed on a recording medium determined by the user to adjust the apparatus to be a non-defective product can be detected by the image detection sensor unit and used as reference image data serving as a reference for image quality determination. As a result, it is possible to perform image quality determination with the image quality desired by the user as a non-defective product, and it is possible to obtain an effect that image quality determination can be performed in accordance with the user's request.

  In addition, the transfer paper on which a non-defective image is formed is supplied from a manual feed tray serving as a paper feed unit and detected by an image detection sensor unit. Thus, the non-defective image can be detected by the image detection sensor unit without providing a dedicated supply unit for supplying the transfer paper on which the non-defective image is formed to the image detection sensor unit. Therefore, the reference image data acquisition mode and the image quality determination operation can be performed only by installing software such as a program for executing the reference image data acquisition mode.

Further, a non-defective image supply tray as a dedicated supply unit for supplying transfer paper on which a non-defective image is formed to the image detection sensor unit as in the first modification may be provided. When a transfer sheet on which a non-defective image is formed is fed from the manual feed tray 43, it is necessary for the user to specify whether to perform a normal image forming operation or a reference image data acquisition mode by an operation. However, by providing the non-defective image supply tray 111, when the transfer paper is set in the non-defective image supply tray 111, only the reference image data acquisition mode can be executed, so that the reference image data acquisition mode is automatically executed. Is also possible. As a result, it is possible to suppress work effort and mistakes in procedure.
If the non-defective image supply tray 111 is provided on the paper discharge side, the transfer paper on which the non-defective image is formed can reach the image detection sensor unit without passing through the secondary transfer unit or the fixing device. . As a result, it is possible to suppress the deterioration of the non-defective image due to dirt in the secondary transfer unit or heat of the fixing device.

  In addition, a second discharge tray serving as a regular recording medium discharge unit from which a transfer sheet on which an image determined to be a normal image is formed is discharged, and a transfer sheet on which an image determined to be an abnormal image is discharged. Whether to transfer the transfer paper being conveyed to the first paper discharge tray or to the second paper discharge tray based on the determination result of the first paper discharge tray as the abnormal recording medium discharge unit and the image quality determination means. And a second switching claw as switching means for switching. Thereby, the transfer paper determined to be an abnormal image can be discharged separately from the transfer paper of the normal image. As a result, it is possible to save time and labor for the user to visually inspect the output and remove the defective image. Thereby, a user's load can be reduced and a user's satisfaction improvement can also be obtained. Further, by discharging the transfer paper on which the abnormal image is formed to the paper discharge tray on which the transfer image on which the normal image is formed, the user can reliably identify the transfer paper on which the abnormal image is formed.

  In the second modification, a test transfer paper storage unit is provided as a dedicated recording medium storage unit for storing a test transfer paper on which a test pattern is formed when the image quality adjustment mode as image forming condition adjustment means is executed. By supplying the test transfer paper into the unit by the serviceman, it is not necessary to use the transfer paper in the normal paper feed cassette, which is the property of the user, for forming the test pattern. This eliminates user dissatisfaction caused by wasteful use of transfer paper in the image quality adjustment mode.

  Further, the test transfer paper on which the test pattern after passing the test pattern detection sensor unit as the test pattern detection means is formed may be stored in the test transfer paper storage unit. With this configuration, the unused area of the test transfer paper that has been used once can be reused in the next image quality adjustment mode. As a result, consumption of the test transfer paper can be suppressed, leading to resource saving. In addition, the test paper on which the test pattern is formed is returned to the test transfer paper storage unit without being discharged to the paper discharge tray, so that the user has the trouble of discarding the transfer paper on which the test pattern is formed. It is possible to reduce user dissatisfaction items.

  Also, by arranging the test pattern detection sensor unit in the test transfer paper storage unit, the hardware configuration for executing the image quality adjustment mode can be integrated into one unit. Thereby, it becomes possible to install as an option unit independently. As a result, it can be provided as an optional unit for customers who want more stable images over time.

  In addition, by providing access prohibition means (screwing with a cover member, warning text, etc.) that prohibits access to the test transfer paper in the test transfer paper storage unit, the test in the user's test transfer paper storage unit Access to the transfer paper can be suppressed. As a result, the user can be prevented from performing an action such as replacing the test transfer paper stored in the test transfer paper storage unit. Thus, the image quality adjustment mode can be executed with a predetermined type of test transfer paper, and good image quality adjustment can be performed. Further, it is possible to prevent the test pattern formation history from being lost when the same test transfer paper is repeatedly used.

  Further, the test transfer paper storage unit can be replaced with the same size as a normal paper feed cassette, so that it can be provided as an optional unit for stabilizing the image quality. As a result, a user who desires a more stable image quality over time has this optional unit installed instead of one stage of the paper feed cassette, and the image quality adjustment mode cannot be executed. In addition, for a user whose image quality may be normal quality, a paper cassette is attached and the image quality adjustment mode cannot be set. In this way, a configuration reflecting the user's request is possible, and the satisfaction of the user can be enhanced in terms of both performance and cost.

  In addition, by providing the post-processing device with the image detection sensor unit and the non-defective image supply tray, the post-processing device can execute the reference image data acquisition mode. This eliminates the need to go through the image forming apparatus main body side for obtaining the reference image data. That is, it is not necessary to provide an additional function for the reference image data acquisition mode on the image forming apparatus main body side.

  Furthermore, by providing the post-processing apparatus with image quality determination means, it is possible to add an image quality determination function only by installing the post-processing apparatus without increasing the cost of the image forming apparatus main body. As a result, the image quality can be determined without interposing the image forming apparatus main body, so that a wide range of image forming apparatuses can be supported.

1 is a schematic configuration diagram of a copier according to a first embodiment. The figure which showed typically the control part of the copying machine. The figure which illustrates extraction of a feature-value typically. The figure which illustrates typically extraction of the feature-value when the area for extracting a feature-value is further miniaturized. FIG. 9 is a schematic configuration diagram of a copier according to a first modification. FIG. 10 is a schematic configuration diagram illustrating an example of a copying machine according to a second modification. The schematic perspective view of a test pattern detection sensor unit. FIG. 10 is a schematic configuration diagram showing another example of a copying machine according to Modification 2. FIG. 10 is a schematic configuration diagram illustrating another example of a copying machine according to Modification 2. FIG. 3 is a schematic configuration diagram of an image forming system according to a second embodiment.

Explanation of symbols

17: intermediate transfer unit 20: image forming unit 43: manual feed tray 81: first paper discharge tray 82: second paper discharge tray 83: second switching claw 87: first switching claw 89: paper discharge path 91: image detection sensor Unit 110: Post-processing device 111: Non-defective image supply tray 115: Test transfer paper storage unit

Claims (14)

Image forming means for forming an image on a recording medium based on the image data;
Image detection means for detecting an image on a recording medium;
An image on the recording medium formed by the image forming unit is detected by the image detecting unit, inspection image data is obtained, and on the recording medium formed by the image forming unit based on the inspection image data In an image forming apparatus comprising image quality determination means for determining image quality of
A control means for detecting a non-defective image formed on a recording medium by the image detection means and executing a reference image data acquisition mode for acquiring reference image data serving as a reference for image quality determination;
An image forming apparatus comprising: the image quality determining unit configured to perform image quality determination of an image on a recording medium formed by the image forming unit based on the reference image data and the inspection image data. . The image forming apparatus according to claim 1.
A paper feeding unit that conveys a recording medium to the image forming unit;
An image forming apparatus configured to supply a recording medium on which the non-defective image is formed from the sheet feeding unit and detect the recording medium by the image detecting unit. The image forming apparatus according to claim 1.
An image forming apparatus comprising a dedicated supply unit for supplying the recording medium on which the non-defective image is formed to the image detecting means. The image forming apparatus according to any one of claims 1 to 3,
A regular recording medium discharge unit for discharging a recording medium on which an image determined as a normal image by the image quality determination unit is recorded;
An abnormal recording medium discharge unit for discharging a recording medium on which an image determined to be an abnormal image by the image quality determination means is recorded;
And switching means for switching whether the recording medium being conveyed is discharged to the regular recording medium discharge section or the abnormal recording medium discharge section based on the determination result of the image quality determination section. Image forming apparatus. The image forming apparatus according to claim 1,
A test pattern is formed on the recording medium, detected by a test pattern detecting unit that detects the test pattern on the recording medium, and includes an image forming condition adjusting unit that adjusts an image forming condition based on the detection result;
An image forming apparatus comprising a dedicated recording medium storage unit for storing a dedicated recording medium on which the test pattern is formed. The image forming apparatus according to claim 5.
An image forming apparatus comprising: an image forming condition adjusting unit configured to store, in the dedicated recording medium storing unit, a dedicated recording medium on which the test pattern after passing the test pattern detecting unit is formed. The image forming apparatus according to claim 6.
An image forming apparatus, wherein the test pattern detecting means is arranged in the dedicated recording medium storage unit. The image forming apparatus according to any one of claims 5 to 7,
An image forming apparatus comprising: an access prohibiting unit that prohibits access to the dedicated recording medium in the dedicated recording medium storage unit. The image forming apparatus according to any one of claims 5 to 7,
An image forming apparatus characterized in that the dedicated recording medium storage unit can be replaced with a paper feed unit for storing a normal recording medium. An image forming apparatus including an image forming unit that forms an image on a recording medium based on image data;
An image forming system including a post-processing device that performs post-processing of a recording medium on which an image is formed by the image forming device.
Image detection means for detecting an image on a recording medium;
Control means for detecting a non-defective image formed on a recording medium by the image detection means and executing a reference image data acquisition mode for acquiring reference image data serving as a reference for image quality determination;
An image on the recording medium formed by the image forming apparatus is detected by the image detecting means, inspection image data is obtained, and the image forming apparatus performs the inspection based on the reference image data and the inspection image data. An image forming system comprising image quality determining means for determining image quality of an image on a formed recording medium. The image forming system according to claim 10.
The image processing means is provided in the post-processing device;
An image forming system, wherein a dedicated supply unit for supplying a recording medium on which the non-defective image is formed to the image detecting means is provided in the post-processing apparatus. The image forming system according to claim 11.
An image forming system comprising a control means for executing the reference image data acquisition mode in the post-processing apparatus. The image forming system according to claim 10.
The post-processing device includes:
A regular recording medium discharge unit for discharging a recording medium on which an image determined as a normal image by the image quality determination unit is recorded;
An abnormal recording medium discharge unit for discharging a recording medium on which an image determined to be an abnormal image by the image quality determination means is recorded;
And switching means for switching between discharging the recording medium being conveyed to the regular recording medium discharge section or discharging to the abnormal recording medium discharge section based on the determination result of the image quality determination section. Image forming system. In a post-processing apparatus that performs post-processing of a recording medium on which an image is formed by an image forming apparatus,
Image detection means for detecting an image on a recording medium;
Control means for detecting a non-defective image formed on a recording medium by the image detection means and executing a reference image data acquisition mode for acquiring reference image data serving as a reference for image quality determination;
An image on the recording medium formed by the image forming apparatus is detected by the image detecting means, inspection image data is obtained, and the image forming apparatus performs the inspection based on the reference image data and the inspection image data. A post-processing apparatus, comprising: an image quality determination unit configured to perform image quality determination of an image on a formed recording medium.

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