Image formation apparatus

Abstract

To provide an image formation apparatus capable of preventing problems in a print inspection due to shortage of an available capacity in a memory that stores inspection result data.SOLUTION: An image formation apparatus includes: a printer that forms an image on a sheet on the basis of image data to produce printed matter; a reading unit that reads the image formed on the printed matter; an inspection device that performs an inspection on the reading result of the image; a controller that executes printing using the printer in response to a print instruction; and a storage that stores the inspection results. The controller determines whether deletion conditions are satisfied for the stored inspection results, and selectively deletes the inspection results for which the deletion conditions are satisfied from the storage.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus having a print inspection function for inspecting the quality of an image printed on paper. [Background technology]

[0002] An image forming device generates a printed matter by printing an image on paper based on image data representing the image to be printed. In particular, image forming devices used at commercial printing sites may print a large number of copies or pages at once. Patent Document 1 discloses a method of performing a trial print in which only specific pages are printed before the actual printing. In addition, a print inspection device inspects whether the image printed on paper by the image forming device is formed as instructed by the image data.

[0003] The print inspection device uses image data as reference data and scan data obtained by reading an image printed on paper with a sensor such as a scanner as test image data, and compares the two sets of data. The print inspection device judges the print quality of the printout based on the degree of match between the reference data and the test image data. The print inspection device performs print inspection according to settings such as the inspection area and inspection intensity that are set in advance by the user. Once the print inspection is performed, the inspection result data is saved in the image forming device. This is the same for both actual printing and test printing.

[0004] In most cases, when a test print is performed, the test data stored in the image forming device after printing is completed is The inspection result data is not necessary. However, if the inspection result data is not deleted and is kept, it may put pressure on the memory inside the image forming device, and the free memory capacity may become small. Patent Document 1 does not disclose the free memory capacity of the image forming device. Patent Document 2 discloses a technique to be used when memory is under pressure in this way. With this technique, when the free memory capacity is low, the reference data is not saved, and a print inspection is performed by comparing the document image with the inspection image data. [Prior art documents]

Patent Document

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, Patent Document 2 relates to a technique used when the memory capacity for storing reference data in the memory inside the image forming apparatus is reduced. That is, Patent Document 2 does not disclose a technique for the case where the free capacity of the memory for storing inspection result data is reduced. Therefore, if the free capacity of the memory for storing inspection result data runs out, there is a risk of a malfunction occurring and the print inspection becoming impossible. For this reason, a technique for preventing problems from occurring in the print inspection due to a shortage of the free capacity of the memory for storing inspection result data is required.

[0007] In view of the above problems, an object of the present invention is to prevent problems from occurring in the print inspection due to a shortage of the free capacity of the memory for storing inspection result data.

Means for Solving the Problems

[0008] The image forming apparatus of the present invention includes a printing unit that forms an image on a sheet based on image data to generate a printed matter, a reading unit that reads the image formed on the printed matter, an inspection unit that executes an inspection of the reading result of the image by the reading unit, a control unit that causes the printing unit to execute printing in response to a printing instruction, and a storage unit that stores the inspection result in the inspection. The control unit determines whether a predetermined deletion condition is satisfied for the stored inspection result, and selectively deletes the inspection result for which the predetermined deletion condition is satisfied from the storage unit.

Effects of the Invention

[0009] According to the present invention, it is possible to prevent problems from occurring in the printing inspection due to insufficient free capacity of the memory for storing inspection result data.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

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Figure 9

Figure 10

Modes for Carrying Out the Invention

[0011] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Unless otherwise specified, the following embodiments can be arbitrarily combined. In addition, these embodiments and modifications do not limit the invention according to the claims, and not all combinations of the features described in the embodiments are essential for the solution means of the invention.

[0012] (Configuration of the Printing System) FIG. 1 is a configuration diagram of an image forming system including the printing inspection apparatus of the present embodiment. The image forming system 1 includes an operation unit 200, a printer 300 as an image forming unit, a controller 400 as control means, an inspection apparatus 500 as image inspection means, a stacker 600, and a finisher 700 as a post-processing unit.

[0013] The operation unit 200 is a user interface including an input interface and an output interface. The input interface is, for example, an input key, a touch panel, or the like. The output interface is, for example, a display, a speaker, or the like. Accordingly, the operation unit 200 has a function as information presenting means through vision and hearing. The operation unit 200 transmits an instruction or data input from the input interface to the controller 400. Further, the operation unit 200 outputs information from the output interface according to an instruction from the controller 400.

[0014] The controller 400 controls the operations of the printer 300, the inspection apparatus 500, the stacker 600, and the finisher 700 based on an instruction or data input from the operation unit 200, or an instruction or data acquired from an external device via a network. For example, when performing image formation, the controller 400 transmits an image formation instruction to the printer 300. Details of the controller 400 will be described later.

[0015] (Printer) The printer 300 of this embodiment is a color image forming apparatus that prints a color image on paper and functions as a printing means. The printer 300 includes an image forming unit Y, M, C, K, an intermediate transfer member 306, a transfer unit 307, a fixing unit 308, paper feed cassettes 311, 312, and a paper feeding mechanism. The image forming unit Y forms a yellow (Y) image. The image forming unit M forms a magenta (M) image. The image forming unit C forms a cyan (C) image. The image forming unit K forms a black (K) image. The intermediate transfer member 306 has the respective color images formed by the image forming units Y, M, C, K superimposed and transferred thereon. The transfer unit 307 transfers the image carried on the intermediate transfer member 306 to the paper. The fixing unit 308 fixes the image transferred to the paper onto the paper. Each of the image forming units Y, M, C, K has the same configuration and forms an image by the same operation. Here, the configuration of the image forming unit Y will be described, and the description of the configurations of the image forming units M, C, K will be omitted.

[0016] The image forming unit Y includes a photosensitive drum 301Y, a charger 302Y, an exposure device 303Y, and a developing device 304Y. The photosensitive drum 301Y is a drum-shaped photoreceptor having a photosensitive layer on its surface. The photosensitive drum 301Y rotates in the direction of arrow R about the drum axis during operation. The charger 302Y uniformly charges the surface of the rotating photosensitive drum 301Y. The exposure device 303Y acquires image data representing a yellow image from the controller 400 and outputs a laser beam turned on according to the image data. The laser beam output from the exposure device 303Y scans the surface of the charged photosensitive drum 301Y in the drum axis direction.

[0017] By scanning the surface of the rotating photosensitive drum 301Y with the laser beam, an electrostatic latent image corresponding to the yellow image data is formed on the surface of the photosensitive drum 301Y. The developing device 304Y stores a yellow developer (for example, toner) and develops the electrostatic latent image formed on the photosensitive drum 301Y with the developer. Thereby, a yellow image is formed on the surface of the photosensitive drum 301Y. Note that the developing device 304Y is configured such that the developer can be constantly replenished from a toner cartridge (not shown).

[0018] Similarly, a magenta image is formed on the photosensitive drum 301M of the image forming unit M. A cyan image is formed on the photosensitive drum 301C of the image forming unit C. A black image is formed on the photosensitive drum 301K of the image forming unit K. The intermediate transfer member 306 is an endless belt member and rotates in the clockwise direction in the figure. The intermediate transfer member 306 is in contact with each of the photosensitive drums 301Y, 301M, 301C, and 301K. In accordance with the rotation of the intermediate transfer member 306, the images of each color are sequentially transferred from each of the photosensitive drums 301Y, 301M, 301C, and 301K so as to be superimposed. As a result, a full-color image is formed on the intermediate transfer member 306. By rotating, the intermediate transfer member 306 conveys the full-color image it carries to the transfer unit 307.

[0019] The sheets are stored in the paper feed cassettes 311 and 312 and are conveyed from the paper feed cassettes 311 and 312 to the transfer unit 307 by a paper feed mechanism. The conveyance of the sheets is performed in accordance with the timing at which the image carried on the intermediate transfer member 306 is conveyed to the transfer unit 307. The transfer unit 307 transfers the image from the intermediate transfer member 306 to the sheet. A cleaner 309 is disposed on the downstream side of the transfer unit 307 in the rotation direction of the intermediate transfer member 306. The cleaner 309 removes the developer remaining on the intermediate transfer member 306 after the transfer.

[0020] The sheet on which the image has been transferred is conveyed from the transfer unit 307 to the fuser 308. The fuser 308 includes a heater and a pressure roller. The fuser 308 melts and fixes the image on the sheet by the heat of the heater and the pressure of the pressure roller.

[0021] On the downstream side of the fuser 308 in the paper conveyance direction, conveyance paths 313, 314, 315, a duplex conveyance path 316, and a discharge roller 317 are provided. The paper that has passed through the fuser 308 is once conveyed from the conveyance path 313 to the conveyance path 314. After the rear end of the paper has passed through the conveyance path 313, the conveyance direction is reversed, and the paper is conveyed from the conveyance path 315 to the discharge roller 317. Through such conveyance, the paper is discharged from the printer 300 by the discharge roller 317 with the image-formed surface facing downward (face down). The printed matter, which is the paper after image formation discharged from the printer 300 by the discharge roller 317, is delivered to the inspection device 500.

[0022] In the case of duplex printing on the paper, the paper conveyed to the conveyance path 314 is conveyed to the duplex conveyance path 316 after the rear end has passed through the conveyance path 313. The paper is conveyed to the transfer unit 307 again via the duplex conveyance path 316. By passing through the duplex conveyance path 316, the surface of the paper on which the image is formed is reversed. For the reversed surface, the image transfer process by the transfer unit 307 and the fixing process by the fuser 308 are performed, and thus an image is formed on that surface. The paper with images formed on both sides is discharged from the printer 300 as a printed matter by the discharge roller 317 and delivered to the inspection device 500.

[0023] (Printing Inspection Device) The inspection device 500 includes a conveyance path 501, an inspection control unit 510, a first reading unit 5051a and a second reading unit 5051b that each function as a reading means, flow-through glass 5053a, 5053b, conveyance rollers 502, 503 as conveyance means, and a paper detection sensor 504. The inspection control unit 510 controls the operation of the inspection device 500 under the control of the controller 400. Details of the inspection control unit 510 will be described later. The first reading unit 5051a and the second reading unit 5051b are arranged at positions facing each other via the conveyance path 501. The conveyance rollers 502, 503 convey the printed matter.

[0024] The inspection device 500 detects a printed matter being conveyed on the conveyance path 501 by a paper detection sensor 504, and the first reading unit 5051a and the second reading unit 5051b read the printed image. The first reading unit 5051a and the second reading unit 5051b transmit the reading result of the printed matter to the inspection control unit 510. The inspection control unit 510 performs a quality inspection of the image printed on the printed matter based on the reading result of the printed matter. Since the first reading unit 5051a and the second reading unit 5051b are arranged to face each other via the conveyance path 501, the images printed on both sides of the printed matter are read during a single conveyance of the printed matter. The printed matter on which the image has been read is conveyed from the inspection device 500 to the stacker 600.

[0025] (Stacker, Finisher) The stacker 600 includes a large-capacity tray 610 and a purge tray 620. The stacker 600 discharges the printed matter to either the large-capacity tray 610, the finisher 700, or the purge tray 620 based on an instruction from the controller 400 and the result of the quality inspection by the inspection control unit 510.

[0026] The finisher 700 includes a printed matter conveyance unit 710 including a plurality of conveyance rollers and a conveyance path, an upper paper discharge tray 701, a middle paper discharge tray 702, and a lower paper discharge tray 703. The printed matter conveyance unit 710 includes switching mechanisms 711 and 712 for switching the discharge destination of the printed matter. The finisher 700 sequentially takes in the printed matter from the stacker 600 and discharges the printed matter to either the upper paper discharge tray 701, the middle paper discharge tray 702, or the lower paper discharge tray 703 according to an instruction from the controller 400. Note that the finisher 700 may be configured to perform post-processing such as stapling the printed matter in multiple sheets, binding the bundled printed matter, and cutting the bundled printed matter.

[0027] (Controller) Figure 2 is a configuration diagram of the controller 400. The storage 4100 as the storage means is a large-capacity storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive). In addition to the printer 300, the inspection device 500, and the operation unit 200, the storage 4100 and the power control unit 4500 are connected to the controller 400. The controller 400 includes a storage I / F 4318, an operation unit I / F 4306, a power control I / F 4308, an inspection unit I / F 4317, a printer communication I / F 4307, and a printer I / F 4316 as interfaces with the respective connected units. Further, the controller 400 includes a communication I / F 4305 to communicate with an external device via a network. The storage I / F 4318, the operation unit I / F 4306, the power control I / F 4308, the inspection unit I / F 4317, the printer communication I / F 4307, and the communication I / F 4305 are connected to the system bus 4319.

[0028] The controller 400 includes a CPU (Central Processing Unit) 4301, a ROM (Read Only Memory) 4302, and a RAM (Random Access Memory) 4303. The CPU 4301 controls the operation of the image forming system 1 by executing a computer program stored in the ROM 4302. The RAM 4303 provides a work area when the CPU 4301 executes processing. Further, the RAM 4303 is also used as an image memory for temporarily storing image data and the like. The CPU 4301, the ROM 4302, and the RAM 4303 are also connected to the system bus 4319. The system bus 4319 is also connected to an NVRAM (Non-Volatile RAM) 4304 and a timer 4309. The NVRAM 4304 stores various control parameters. The timer 4309 holds the current time and monitors the elapse of the set time.

[0029] The operation unit I / F 4306 controls communication with the operation unit 200. The operation unit I / F 4306 receives inputs such as print jobs, commands, and print settings from the operation unit 200 to the controller 400 and transmits them to the CPU 4301. Under the control of the CPU 4301, the operation unit I / F 4306 causes various screens and the status of the image forming system 1 to be displayed on the display (display means) of the operation unit 200. The printer communication I / F 4307 controls communication with the printer 300 under the control of the CPU 4301. The power control I / F 4308 instructs the power control unit 4500 to supply / stop various powers according to commands from the CPU 4301. The power control unit 4500 supplies power to the printer 300. The inspection unit I / F 4317 controls communication with the inspection device 500 under the control of the CPU 4301. The storage I / F 4318 controls communication with the storage 4100 under the control of the CPU 4301. The storage 4100 is a large-capacity storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive).

[0030] The communication I / F 4305 is connected to a network such as a LAN (Local Area Network) and controls communication such as sending and receiving emails and input / output of PDL data from external devices. Also, the communication I / F 4305 has an NVRAM (not shown) and holds various parameters related to communication control such as MAC addresses.

[0031] The system bus 4319 is connected to the Image Bus 4311 via the Image Bus I / F 4310. The Image Bus I / F 4310 is a bridge that connects the system bus 4319 and the Image Bus 4311 for transferring image data to the printer 300. Connected to the Image Bus 4311 are the printer I / F 4316, the image compression unit 4312, the image rotation unit 4313, and the RIP (Raster Image Processor) 4314.

[0032] The image compression unit 4312 performs compression and decompression processing such as JPEG, JBIG, MMR, and MH. The image rotation unit 4313 performs image rotation processing. The RIP 4314 expands the PDL code into a bitmap raster image. The printer I / F 4316 transmits the image data to the printer 300. This image data is generated by the controller 400 performing image processing for the printer 300, such as correction for the printer 300 and resolution conversion, on the image data for print output.

[0033] (Inspection control unit) Figure 3 is a configuration diagram of the inspection control unit 510 provided in the inspection apparatus 500. The inspection control unit 510 controls the operations of the first reading unit 5051a and the second reading unit 5051b. The inspection control unit 510 performs processes such as analysis of the reading results of the first reading unit 5051a and the second reading unit 5051b, operation control of the inspection apparatus 500, and communication with the controller 400. Further, the inspection control unit 510 is connected to the storage 5011, which is a storage means for storing the positional deviation correction profile and the like, and the controller 400.

[0034] The inspection control unit 510 includes a CPU 5001, a ROM 5002, a RAM 5003, a storage I / F 5004, a motor control unit 5009, a read image processing unit 5008, an image processing unit 5006, an RTC 5012, a host I / F 5007, and a sensor control unit 5010. Each unit is connected to the system bus 5005. The read image processing unit 5008 is connected to the first reading unit 5051a via the first reading I / F 5052a and to the second reading unit 5051b via the second reading I / F 5052b. The RTC 5012 is a real-time clock and holds the current time with high precision.

[0035] The host I / F 5007 controls communication with the inspection unit I / F 4317 of the controller 400. When the inspection control unit 510 communicates with the controller 400, data is transmitted and received between the host I / F 5007 and the inspection unit I / F 4317. For example, the host I / F 5007 acquires image data used in the image forming operation of the printer 300 from the controller 400. The storage 5011 is a large-capacity storage device such as an HDD or an SSD. The said image data is stored in the storage 5011.

[0036] The CPU 5001 controls the operation of the inspection device 500 by executing a computer program stored in the ROM 5002. The RAM 5003 provides a work area when the CPU 5001 executes processing. The storage I / F 5004 controls communication with the storage 5011 connected to the inspection control unit 510.

[0037] The read image processing unit 5008 acquires the read result of the image of the printed matter from the first reading unit 5051a via the first reading I / F 5052a under the control of the CPU 5001. Also, the read image processing unit 5008 acquires the read result of the image of the printed matter from the second reading unit 5051b via the second reading I / F 5052b under the control of the CPU 5001. The read image processing unit 5008 performs resizing processing, gamma correction processing, etc. on the read result (read data) of the image of the printed matter acquired from the first reading unit 5051a and the second reading unit 5051b to generate read image data, and stores it in the RAM 5003. The first reading unit 5051a and the second reading unit 5051b are configured with a sensor array and can read the entire area of the printed matter conveyed on the conveyance path 501. The first reading unit 5051a reads the image of the first side of the printed matter, and the second reading unit 5051b reads the image of the second side of the printed matter.

[0038] The first reading unit 5051a and the second reading unit 5051b are composed of a light emitting unit and a light receiving unit. The light emitting unit is composed of, for example, a white LED (Light Emitting Diode), and the light receiving unit is composed of, for example, a CMOS sensor with an RGB color filter. The light emitting unit irradiates light on the printed matter conveyed through the conveyance path 501 under the control of the CPU 5001. The light receiving unit decomposes the reflected light from the printed matter into three color components of RGB by the color filter and receives the light, and outputs read data as a light receiving result (reading result). The read data is transmitted to the reading image processing unit 5008.

[0039] The motor control unit 5009 controls the operations of various motors provided in the inspection apparatus 500 under the control of the CPU 5001. The sensor control unit 5010 controls the operations of various sensors provided in the inspection apparatus 500 under the control of the CPU 5001, and notifies the CPU 5001 of the detection results of the sensors. The image processing unit 5006 performs a quality inspection of the printed matter by comparing the image data stored in the storage 5011 (hereinafter referred to as "reference image data") with the read image data stored in the RAM 5003 under the control of the CPU 5001. The reference image data is image data used for image formation by the printer 300 and is stored in the storage 5011. Alternatively, the reference image data may be an image obtained by previously reading a reference image before performing the quality inspection. When comparing, the image processing unit 5006 performs a correction process on the reference image data using parameters obtained by calibration, which will be described later.

[0040] (Printing settings) FIG. 4 is an explanatory diagram of a print setting screen displayed on the display of the operation unit 200 when instructing the printer 300 to print. The user inputs through the print setting screen displayed on the display and executes printing on the printer 300. In the figure, buttons B101 to B104 are buttons for setting the print content, and it is possible to set color selection for printing (color / black and white), selection of the print side (single-sided / double-sided), selection of the paper type, and the discharge destination of the printed matter, etc. Also, the number of copies to be printed can be set using a numeric keypad (not shown). When the print start button, button B105, or the proof print start button, button B106, is pressed, printing is started according to the print settings set by buttons B101 to B104 and the number of copies set using the numeric keypad. The inspection device 500 executes inspection of the printed matter according to preset inspection settings. The existence of buttons B105 and B106 individually enables the inspection device 500 to identify the print mode (normal print mode or proof print mode). The printing operation of the image forming apparatus is the same in any mode. When the cancel button, button B107, is pressed, the settings are canceled and a predetermined initial screen is displayed on the display of the operation unit 200.

[0041] (Inspection settings) FIG. 5 is a configuration explanatory diagram of an inspection setting screen for performing inspection settings of the inspection device 500. This inspection setting screen has a function as a reception means for receiving an instruction from the user for setting an inspection area where inspections such as quality inspection by the inspection device 500 are executed. In the figure, area A501 is a print image and inspection setting area display section. In area A501, the original image in the print job is displayed, and areas A511 to A516 are provided as inspection areas.

[0042] In Fig. 5, when the user selects areas A511 to A516 with the inspection area type buttons shown as buttons B502a to B502d selected, the inspection area can be set. Buttons B502a to B502d are buttons representing the inspection area type. In the figure, button B502a, which is a key inspection area button for setting an area for performing high-precision inspection, and button B502b, which is a standard inspection area button for setting the overall inspection level, are shown. Also, in the figure, button B502c for making detailed settings regarding the variable inspection area and button B502d, which is an inspection exclusion area button for designating an area where inspection is not to be performed, are also displayed, and a total of four types of buttons are shown.

[0043] Buttons B503a and B503b are inspection level setting buttons for stepwise setting the inspection accuracy, for example, from level 1 to level 5, for each inspection area type. The user can set the inspection level for each area of buttons B502a and B502b. In this example, the inspection accuracy is the lowest at inspection level 1, and the inspection accuracy increases as the number of the inspection level gets larger. Button B505 is a setting completion button, and when the user selects this button, the inspection setting is completed. Button B506 is a button for returning to the original screen, and when the machine operator selects this button, the inspection setting process is canceled and returns to a predetermined initial screen.

[0044] For example, by selecting button B502a and then selecting, using a mouse or touch panel or the like, the area where high-precision inspection is required, the area for performing high-precision inspection can be arbitrarily selected. In the example of Fig. 5, high-precision inspection is being performed on a person's face. Also, for the background part, since high-precision inspection is not necessary, it is set as an inspection exclusion area. Therefore, compared with the case of inspecting the entire image without making such a selection, the memory and processing power required for the inspection can be suppressed. Also, by stepwise setting the inspection level, for example, from level 1 to level 5, compared with the case of always performing inspection with a high level of accuracy, the memory and processing power required for the inspection can be suppressed.

[0045] (Print Inspection in Proof Printing) Proof printing is used to confirm whether the printed image, the printing settings of the printer 300, and the inspection settings of the inspection device 500 are correct. For example, there may be a case where there is a character string in the printed image and it is desired to inspect whether the character string printed by the inspection device 500 is correct. In this case, it is necessary to set an area (hereinafter referred to as an inspection area) in which the inspection device 500 performs OCR (Optical Character Recognition) processing to identify the character string. However, if the inspection area is not set correctly, the character string cannot be identified and the inspection fails. When there is an inspection failure during the execution of proof printing, the inspection device 500 notifies the user whether there is an error in the inspection settings through the operation screen of the display of the operation unit 200.

[0046] (Setting of Conditions for Deleting Proof Printing Inspection Result Data) FIG. 6 is an explanatory diagram of a screen for setting conditions for deleting proof printing inspection result data, which is displayed on the display of the operation unit 200. The user sets the conditions for deleting proof printing inspection result data through this setting screen for deletion conditions. In area A610, an explanation "Setting Conditions for Deleting Proof Printing Inspection Result Data" is displayed. In areas A601 to A604, the contents set for deletion condition 1 to deletion condition 3 are respectively displayed. When setting which condition to apply, it can be set by pressing button B604.

[0047] Buttons B601, B602, and B603 are buttons for setting the contents of deletion condition 1, deletion condition 2, and deletion condition 3 respectively, and button B604 is a button for setting deletion conditions. The deletion conditions are one or more selected by the user from three types: "deletion condition 1: elapsed time after proof printing ends", "deletion condition 2: elapsed time after this printing ends", and "deletion condition 3: remaining memory amount". When setting the elapsed time in deletion condition 1, the user presses button B601 and enters the numerical value of the elapsed time. When setting the elapsed time in deletion condition 2, the user presses button B602 and enters the numerical value of the elapsed time. When setting the remaining memory amount in deletion condition 3, the user presses button B603 and enters the numerical value of the remaining memory amount. When setting the deletion conditions, the user presses button B604 and enters any one or an arbitrary combination of deletion conditions 1 to 3. Thereby, the deletion conditions (or combination of deletion conditions) set by the user are displayed in area A604. These deletion conditions 1 to 3 can be set individually or in any combination of AND conditions and OR conditions. An example where an OR condition between deletion condition 1 and deletion condition 3 is set is shown in area A604 of FIG. 6.

[0048] In the example of FIG. 6, for deletion condition 1, 24 hours after the end of proof printing is input by the user as the elapsed time, and for deletion condition 2, 24 hours after the end of this printing is input by the user as the elapsed time. For deletion condition 3, 1 GB or less, which is the numerical value of the remaining free capacity of storage 5011, is input by the user as the remaining memory amount. Note that although deletion condition 1 is the elapsed time after the end of proof printing, it may also be the elapsed time after storing the inspection result data in storage 5011 by proof printing. Also, although deletion condition 2 is the elapsed time after the end of this printing, it may also be the elapsed time after storing the inspection result data in storage 5011 by this printing. Button B605 is a save button for settings. By pressing this button, the settings displayed on the display are saved and applied. Button B606 is a cancel button. By pressing this button, the operation ends without saving the settings.

[0049] (Explanation of the inspection execution screen of the operation unit) FIG. 7 is an explanatory diagram of the operation screen of the operation unit 200 during inspection execution. In the figure, area A701 is an area for displaying the read image. Area A702 is an area for displaying inspection status such as the number of completed inspections, the number of NG inspections, the NG rate, and the types of NG. Area A703 is an area for displaying the status of the printer 300, such as standby, inspection in progress, and inspection completed. In FIG. 7, in area A703, "In progress" indicating that the inspection of the printer 300 is temporarily stopped is displayed.

[0050] FIG. 8(a) is an explanatory diagram of the operation screen of the operation unit 200 when the printer 300 is performing a full-color printing inspection, and FIG. 8(b) is an explanatory diagram of the operation screen when the printer 300 is performing a proofing inspection. In these figures, area A801 is an area for displaying the read image, and area A802 is an area for displaying inspection status such as the number of completed inspections, the number of NG inspections, the NG rate, and the types of NG. Area A803 is an area for displaying status such as standby, inspection in progress, and inspection completed. For example, when the printer 300 is performing full-color printing and the inspection device 500 is in the middle of inspection, as shown in FIG. 8(a), in area A803, the content indicating that the full-color printing inspection is in progress is displayed. Also, when the printer 300 is performing proofing and the inspection device 500 is in the middle of inspection, as shown in FIG. 8(b), in area A703, the content indicating that the proofing inspection is in progress is displayed. As described above, by checking the content displayed in area A803 of the operation unit screen during inspection execution, the user can easily check whether it is a proofing inspection or a full-color printing inspection.

[0051] (Inspection printing process flow) FIG. 9 is a flowchart showing the inspection printing process in the present embodiment. This flowchart summarizes the processes executed by the CPU 4301 of the controller 400 and the CPU 5001 of the inspection apparatus 500, respectively. Further, this inspection printing process is commonly used for both main printing and proof printing. This inspection printing process is executed when the user selects the print start button B105 or the proof printing start button B106 on the print setting screen shown in FIG. 4. When the print start button B105 is selected on the operation screen of the operation unit 200, the CPU 4301 transmits job information including paper information, inspection settings, discharge destination, etc. used for printing to the inspection apparatus 500 (S901). The CPU 5001 receives the job information from the controller 400 (S902). After receiving the job information reception response from the controller 400, the CPU 5001 sends a request to the controller 400 to transmit a reference image serving as a reference for inspection (S903).

[0052] Based on the reference image transmission request from the inspection apparatus 500, the CPU 4301 transmits the original image data of the print job to the inspection apparatus as reference image data (S904). The CPU 5001 receives the reference image from the controller 400, stores it in the storage 5011, and transmits a preparation completion notice to the controller 400 (S905). When receiving the preparation completion notice from the inspection apparatus 500 (S906), the CPU 4301 controls the printer 300 to start printing (S907). Thereafter, the CPU 4301 controls the operation unit 200 to display a screen indicating the start of inspection of the printed matter on the inspection screen (S908).

[0053] The CPU 5001 determines whether a sheet of paper has reached the conveyance path 501 of the inspection apparatus 500 using the paper detection sensor 504 (S909). If the sheet of paper has not reached (S909: No), the determination in S909 is repeated until the sheet of paper is sent. When it is determined that the sheet of paper has reached (S909: Yes), the CPU 5001 reads the image of the incoming sheet of paper using the first reading unit 5051a and the second reading unit 5051b, and instructs the image processing unit 5006 to perform a comparison process with the reference image data received in S905. Thereby, the image processing unit 5006 performs the comparison process and the image inspection is performed (S910). The CPU 5001 transmits the inspection result by the comparison in the image processing unit 5006 to the controller 400 and stores it in the storage 5011 (S911).

[0054] The CPU 4301 determines whether it has received the inspection result (S912). If it has not received it (S912: No), the determination in S912 is repeated again. When the CPU 4301 has received the inspection result (S912: Yes), it controls the operation unit 200 to update the inspection screen according to the inspection result (S913). Thereafter, the CPU 4301 determines whether there is a next page (S914). If there is a next page (S914: Yes), S907 is executed again. When the printing and inspection of all pages are completed, that is, when there is no next page (S914: No), the CPU 4301 controls the operation unit 200 to display on the inspection screen that the inspection has been completed (S915). Thus, the inspection printing process ends.

[0055] (Inspection Result Data Deletion Flow) FIG. 10 is a flowchart showing the deletion process of the inspection result data in this embodiment. This flowchart summarizes the processes executed by the CPU 4301 of the controller 400 and the CPU 5001 of the inspection apparatus 500, respectively. This control is executed at regular intervals by the CPU 4301 regardless of the user's operation. The CPU 4301 sends a transmission request for information regarding the result of one proofing inspection to the CPU 5001 (S1001). In this example, as the information regarding the proofing inspection result data, four pieces of information, namely, "date and time information of the proofing inspection", "date and time information of this printing corresponding to the proofing inspection", "remaining memory capacity capable of storing the inspection result data", and "set deletion conditions of the proofing inspection result", are used. However, it is not limited to these, and other information can also be used.

[0056] The CPU 5001 receives the information transmission request from the controller 400 (S1002) and transmits the requested information to the CPU 4301 (S1003). In this example, the CPU 5001 transmits the above four pieces of information. The CPU 4301 receives the requested information (S1004), checks whether the deletion conditions of the proofing inspection result data are satisfied (S1005), and determines whether the deletion conditions are satisfied (S1006). If the deletion conditions are not satisfied (S1006: No), the CPU 4301 executes the process of S1012, which will be described later. If the deletion conditions are satisfied (S1006: Yes), the CPU 4301 sends a deletion request for the proofing inspection result data to the CPU 5001 (S1007).

[0057] The CPU 5001 receives a deletion request from the CPU 4301 (S1008), deletes the proofing inspection result data stored in the storage 5011 (S1009), and notifies the CPU 4301 that the proofing inspection result data has been deleted (S1010). In this way, the inspection results that meet the deletion conditions are selectively deleted. The CPU 4301 receives the notification from the CPU 5001 of the inspection device 500 and confirms that the proofing inspection result data has been deleted (S1011). Then, the CPU 4301 determines whether all the proofing inspection result data has been confirmed (S1012). If there is unconfirmed proofing inspection result data remaining (S1012: No), the CPU 4301 executes S1001 again. When all the proofing inspection result data has been confirmed (S1012: Yes), the deletion process of the inspection result data ends. By performing the deletion process of the inspection result data in this way, the user can selectively delete the inspection results that meet the deletion conditions and suppress the compression of the memory for storing the inspection result data. Therefore, the user can perform the printing inspection comfortably.

[0058] Also, when the proofing inspection result data meets the deletion conditions in S1006, the CPU 4301 may display on the display of the operation unit 200 that there is an inspection result that meets the deletion conditions. In this case, a screen prompting approval of the deletion of the inspection result data is displayed on the display of the operation unit 200, and the deletion process of the inspection result data is interrupted until approval is obtained, and the processes after S1007 are not performed. Further, a screen that allows the user to select whether to continue or cancel the process of deleting the inspection result data is displayed on the display of the operation unit 200, and after the user selects to continue the process, the process of deleting the inspection result data is continued. When the user selects to cancel the process, the process of deleting the inspection result data is cancelled. In this case, the user can ensure the free capacity of the storage 5011 by deleting data other than the inspection result data, such as reference image data.

[0059] Note that the above-described deletion process for inspection result data can also be used in combination with other data deletion processes. For example, when the memory capacity exceeds a predetermined amount, it may be used in combination with a data deletion process that deletes old data regardless of the type of data (e.g., whether it is inspection result data or reference image data). On the other hand, by performing the above-described inspection data deletion process, it is possible to delete the inspection result data that satisfies the deletion conditions as those with low priority in data storage, and leave other data with high priority in the memory.

[0060] Also, as a modification, in addition to deleting the inspection result data, it is also possible to perform a deletion process for the reference image data stored in the storage 5011 in conjunction with the deletion of the inspection result data. In this case, the priority of the reference image data in data storage is determined by an arbitrary method, and the reference image data with a priority lower than a predetermined standard is deleted from the storage 5011. Also, at the time of executing an inspection such as this printing inspection or proof printing inspection, the reference image data used in the inspection and the inspection result data in that inspection may be associated. Further, for the reference image data associated with the inspection result data determined to be deleted by the above-described deletion process, the priority in data storage may be lowered as a candidate for deletion from the storage 5011. This is because it can be determined that the probability that the reference image data used in the inspection is also less necessary when the inspection result data is deleted is high.

[0061] As a result, it becomes possible to preferentially delete the reference image data associated with the deleted inspection result data. Further, for the reference image data with a plurality of associated inspection result data, it may not be considered as a deletion candidate, or the priority in data storage may be increased. This is because it can be determined that the higher the number of inspection result data associated with the reference image data, the higher the probability that the reference image data is necessary. With such a configuration, it becomes possible to perform the deletion process for the reference image data in conjunction with the result of the deletion process for the inspection result data.

Claims

1. Printing means for forming an image on a sheet based on image data to generate a printed matter; Reading means for reading the image formed on the printed matter; Inspection means for executing an inspection of the reading result of the image by the reading means; Control means for causing the printing means to execute printing in response to a printing instruction; Storage means for storing the inspection result in the inspection; and The control means determines whether a predetermined deletion condition is satisfied for the stored inspection result, and deletes the inspection result for which the predetermined deletion condition is satisfied from the storage means. Characterized in that, An image forming apparatus.

2. Further comprising reception means for receiving an operation from a user, The image forming apparatus according to claim 1, wherein the predetermined deletion condition is settable through the reception means.

3. The control means determines whether the predetermined deletion condition is satisfied at a predetermined cycle for the stored inspection result. Characterized in that, The image forming apparatus according to claim 1.

4. The control means causes the printing means to execute a proof print in response to a proof print instruction, The image forming apparatus according to claim 1, wherein the predetermined deletion condition includes an elapsed time after the end of the proof print for which the inspection was performed.

5. The control means causes the printing means to execute the main print in response to a main print instruction, The image forming apparatus according to claim 1, wherein the predetermined deletion condition includes an elapsed time after the end of the main print for which the inspection was performed.

6. The image forming apparatus according to claim 1, wherein the predetermined deletion condition includes the remaining free capacity of the storage means.

7. Further comprising display means, The image forming apparatus according to claim 1, wherein when there is an inspection result that satisfies the predetermined deletion condition, the control means causes the display means to display that there is an inspection result that satisfies the predetermined deletion condition.

8. The image forming apparatus according to claim 7, wherein the control means causes the display means to display a screen that enables selection of whether to continue or cancel the deletion of the inspection result for which the predetermined deletion condition is satisfied.

9. The inspection is performed using a reference image that is stored in the storage means and serves as a reference for the inspection, The reference image is associated with the inspection result, The image forming apparatus according to any one of claims 1 to 8, characterized in that the reference image associated with the inspection result for which the predetermined deletion condition is satisfied is set as a deletion candidate from the storage means.

10. The image forming apparatus according to claim 9, characterized in that when there are a plurality of inspection result data associated with the reference image, the reference image is not set as the deletion candidate.

Images