Image forming device

Abstract

To make a time required for completely forming an image short, in comparison with in a conventional structure having one storage part that temporarily retains a medium having an image formed thereon.SOLUTION: An image forming device (U) is provided with: temporarily storing means (U5) having a plurality of temporarily storing parts (2A-2D) that can temporarily store media (S); and storage control means (C5) that makes a first temporarily storing part (2A) that is one of the temporarily storing parts (2A-2D) store the media (S) fed after last media have been determined to be improper, makes a second temporarily storing part (2B) different from the first temporarily storing part (2A) store reformed media (S) when a reformed image is determined to be proper, makes the second temporarily storing part (2B) feed the reformed media (S) after the media (S) fed before the media determined to be improper are fed to post-processing means (U6), and thereafter, makes the first temporarily storing part (2A) feed the media (S) fed after the media are determined to be improper.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] 2. Description of the Related Art Regarding a technique for inspecting a formed image in an image forming apparatus and reprinting if the image is unacceptable, the techniques described in Patent Documents 1 and 2 listed below are conventionally known.

[0003] Patent Document 1 describes a technology in which, when printing multiple pages, each printed sheet is inspected, and if the inspection is OK, it is kept in the stacker (511), and if it is NG, it is discharged to the escape tray (611). In Patent Document 1, the NG page (nth page) is repeatedly reprinted until it is judged OK. Then, pages that pass inspection are transported from the stacker (511) to the finisher (103), and pages that fail inspection are transported directly to the finisher (103) without passing through the stacker (511), so that the order of the pages is aligned at the finisher (103).

[0004] Patent Document 2 describes a technology in which each sheet is inspected, and sheets that pass inspection are sent to the sheet processing device (300), and defective sheets that fail inspection are discharged to an inspection tray (505). In Patent Document 2, the sheet following the defective sheet and on which an image is being formed (a contrived sheet) is held in a buffer tray (502) after it is fixed. Then, the image of the defective sheet is printed on a replacement sheet following the contrived sheet. If the replacement sheet fails inspection, it is discharged to the inspection tray (505), and the next replacement sheet is fed, and reprinting is repeated until the replacement sheet passes inspection. If the replacement sheet passes inspection, the replacement sheet is sent to the sheet processing device (300), and then the sheet of the succeeding page is sent from the buffer tray (502) to the sheet processing device (300) to control the order of the pages to be aligned. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-123813 A ("0029"-"0079", Figs. 5, 6, 8-11) [Patent Document 2] JP 2004-020650 A ("0039"-"0074", Figs. 1-4, 8, 9) Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has a technical object to shorten the time until image formation is completed, as compared with a conventional configuration having one storage section that temporarily holds a medium after image formation. [Means for solving the problem]

[0007] In order to solve the above technical problem, the image forming apparatus according to the invention described in claim 1 comprises: A forming means for forming an image on a medium; a reading means for reading the image formed by the forming means; an inspection means for inspecting an image on a medium based on an original image formed by the formation means and an image read by the reading means; a discharge means for discharging a medium on which an image determined to be unsuitable by the inspection means is formed; a temporary storage means having a plurality of temporary storage sections capable of temporarily storing media, the temporary storage section being capable of transporting the media stored in the temporary storage sections toward a post-processing means; the forming means for forming again the image determined to be unsuitable; a storage control means for storing a medium on which an image subsequent to the image determined to be unsuitable is formed in a first temporary storage section which is one of the temporary storage sections, and when the reconstructed image is determined to be suitable, storing the medium on which the reconstructed image is formed in a second temporary storage section different from the first temporary storage section, and, after the medium on which the image prior to the image determined to be unsuitable is formed has been sent to the post-processing means, sending the medium on which the reconstructed image is formed from the second temporary storage section to the post-processing means, and then sending the medium on which the image subsequent to the image determined to be unsuitable is formed from the first temporary storage section to the post-processing means; The present invention is characterized by comprising:

[0008] The invention described in claim 2 is the image forming apparatus described in claim 1, a conveying means disposed between the reading means and the temporary storage means, the conveying means having a conveying path of a length sufficient to ensure the time until the processing by the inspection means is completed; The present invention is characterized by comprising:

[0009] The invention described in claim 3 is the image forming apparatus described in claim 2, the discharge means connected to the downstream side of the conveying path; a switching means for switching a destination of the medium conveyed along the conveying path between the ejection means and the temporary storage means in accordance with an inspection result; The present invention is characterized by comprising:

[0010] The invention described in claim 4 is the image forming apparatus described in claim 1, When forming a plurality of copies of an image, each copy is stored in a different temporary storage unit. It is characterized by:

[0011] The invention described in claim 5 is the image forming apparatus described in claim 4, When forming the image of the plurality of copies, if there is an image that is determined to be unsuitable in the preceding copy of the image formed, and if all the images of the succeeding copy of the image formed are determined to be suitable in the inspection, the succeeding copy of the medium is sent to the post-processing means first. It is characterized by:

[0012] The invention described in claim 6 is the image forming apparatus described in claim 4, The re-formation of the image determined to be unsuitable is performed during the period after the image formation of the preceding copy is completed and before the image formation of the succeeding copy is started. It is characterized by:

[0013] The invention described in claim 7 is the image forming apparatus described in claim 1, When the reconstructed image is inappropriate and the second reconstructed image is appropriate, the second reconstructed medium is stored in a third temporary storage unit different from the first temporary storage unit and the second temporary storage unit. It is characterized by:

[0014] The invention described in claim 8 is the image forming apparatus described in claim 7, The media stored in the first temporary storage unit, the second temporary storage unit, and the third temporary storage unit are sent to the post-processing means in the order of earliest delivery. It is characterized by:

[0015] The invention described in claim 9 is the image forming apparatus described in claim 1, a direct path for conveying the medium from the reading means to the post-processing means without passing through the temporary storage section; Until an image determined to be unsuitable in the inspection occurs, the medium of the image determined to be suitable in the inspection is sent to the post-processing means via the direct path. It is characterized by:

[0016] The present invention relates to an image forming apparatus comprising: The medium of the image determined to be suitable is stored in one of the plurality of temporary storage units. It is characterized by: Effect of the Invention

[0017] According to the first aspect of the present invention, the time required to complete image formation can be reduced, compared to a conventional configuration having one storage section for temporarily holding a medium after image formation. According to the invention as recited in claim 2, it is possible to ensure the time required for the inspection process to be completed before the goods are accommodated in the temporary accommodation means. According to the invention as recited in claim 3, media not suitable for inspection can be discharged to the discharge means. According to the invention described in claim 4, inspection, storage, and sending can be performed for each copy. According to the invention as set forth in claim 5, post-processing of the subsequent part can be performed without waiting for the reformation of the preceding part, thereby shortening the overall time until the image processing is completed.

[0018] According to the invention as set forth in claim 6, the preceding portion can be reformed after the preceding portion, and the preceding portion can be processed with priority. According to the seventh aspect of the present invention, reprinted media and third-reprinted media can be stored and sent out in an order that is not out of order, as compared to a case in which the reprinted media and the third-reprinted media are stored in the same temporary storage section. According to the invention described in claim 8, even if there is a medium to be reprinted a third time in the middle of a reprinted medium, the third temporary storage section can be used to send the medium to the post-processing device without disrupting the order. According to the invention as recited in claim 9, shortage of the temporary storage unit is suppressed, compared to a case in which the suitable medium is not sent out through a direct path. According to the invention described in claim 10, when media determined to be suitable is also stored in the temporary storage section, if all subsequent copies are first determined to be suitable through inspection, the preceding copy can be smoothly replaced with the subsequent copy. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is an explanatory diagram of an image forming apparatus according to a first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating the image forming apparatus of FIG. [Diagram 3] FIG. 3 is a functional block diagram of the control unit according to the first embodiment. [Figure 4]Figure 4 is an explanatory diagram of an example of the storage and ejection of recording paper in the buffer tray of Example 1, where Figure 4A is an explanatory diagram of a case in which recording paper that fails inspection occurs in the first job but does not fail inspection in the second job, and Figure 4B is an explanatory diagram of a case in which up to the third job is executed after the first job is reprinted. [Diagram 5] Figure 5 is an explanatory diagram of another example of the storage and ejection of recording paper in the buffer tray of Example 1, where Figure 5A is an explanatory diagram of the case where multiple recording papers fail inspection in a first job, and Figure 5B is an explanatory diagram of the case where a second job is executed after Figure 5A. [Figure 6] Figure 6 is an explanatory diagram of yet another example of the storage and ejection of recording paper in the buffer tray of Example 1. Figure 6A is an explanatory diagram of the case where multiple recording papers fail inspection in the first job, similar to Figure 5A. Figure 6B is an explanatory diagram of the case where inspection fails even when reprinted after Figure 6A. Figure 6C is an explanatory diagram of the case where inspection is OK after the third reprint. [Figure 7] FIG. 7 is a flowchart of an image forming process in the marking unit of the first embodiment. [Figure 8] FIG. 8 is a flowchart of the inspection process in the inspection device of the first embodiment. [Figure 9] FIG. 9 is a flowchart of a paper storage process in the buffer unit according to the first embodiment. [Figure 10] FIG. 10 is a flowchart of the paper sending process in the buffer unit according to the first embodiment. [Figure 11] FIG. 11 is a block diagram of the second embodiment, and corresponds to FIG. 3 of the first embodiment. [Figure 12] FIG. 12 is a flowchart of a paper storage process in the buffer unit according to the second embodiment. [Figure 13] Figure 13 is an explanatory diagram of an example of the storage and ejection of recording paper in the buffer tray of Example 2, where Figure 13A is an explanatory diagram of the case where recording paper that has been reprinted in the second job is stored in a tray that stores recording paper that has passed inspection from the beginning of the first job, and Figure 13B is an explanatory diagram of the state in which recording paper of the first job has been sent out from the state of Figure 13A. [Figure 14] FIG. 14 is a block diagram of the third embodiment, and corresponds to FIG. 3 of the first embodiment. [Figure 15] Figure 15 is an explanatory diagram of an example of the storage and ejection of recording paper in the buffer tray of Example 3, where Figure 15A is an explanatory diagram of the case where the second and fourth pages are reprinted, and Figure 15B is an explanatory diagram of the state in which the reprinted second and fourth pages of recording paper are stored from the state of Figure 15A. [Figure 16] FIG. 16 is a flowchart of the image forming process in the marking unit of the first embodiment. [Figure 17] FIG. 17 is a flowchart of a paper storage process in the buffer unit according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Next, examples of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following examples. In order to make the following explanation easier to understand, in the drawings, the front-to-back direction (width direction of the medium) is defined as the X-axis direction, the left-to-right direction (direction of medium transport) is defined as the Y-axis direction, and the up-down direction is defined as the Z-axis direction, and the directions or sides indicated by arrows X, -X, Y, -Y, Z, -Z are defined as the front, rear, right, left, upper, and lower, or the front side, rear side, right side, left side, upper side, and lower side, respectively. In addition, in the figures, a "·" inside a "○" means an arrow going from the back to the front of the page, and an "×" inside a "○" means an arrow going from the front to the back of the page. In the following description using the drawings, illustrations of components other than those necessary for the description are omitted as appropriate to facilitate understanding. EXAMPLES

[0021] (Explanation of Overall Configuration of Printer U in First Embodiment) FIG. 1 is an explanatory diagram of an image forming apparatus according to a first embodiment. FIG. 2 is a diagram illustrating the image forming apparatus of FIG. In Figures 1 and 2, a printer U as an example of an image forming apparatus according to a first embodiment of the present invention has a printer main body U1, a feeder unit U2 as an example of a supplying device that supplies media to the printer main body U1, a user interface UI as an example of an operation unit operated by a user, a reading unit U3 as an example of a reading device, a purge unit U4 as an example of a conveying means, a buffer unit U5 as an example of a temporary storage means, and a finisher U6 as an example of a post-processing means.

[0022] (Description of Marking Configuration in Example 1) 1, the main body U1 of the printer includes a control unit (an example of a control means) C that controls the printer U, a communication unit (not shown) that receives image information transmitted from a print image server COM (an example of an information transmitting device) connected to the outside of the printer U via a dedicated cable (not shown), and a marking unit U1a (an example of a forming means) that forms an image on a medium. A personal computer PC (an example of an image transmitting device) is connected to the print image server COM via a line such as a cable or a LAN (Local Area Network) and transmits information of an image to be printed by the printer U. The marking unit U1a has photoconductors Py, Pm, Pc, and Pk for each color, Y: yellow, M: magenta, C: cyan, and K: black, as an example of an image holding means, and a photoconductor Po for making an image glossy when printing a photographic image, etc. The photoconductors Py to Po have surfaces made of a photosensitive dielectric material.

[0023] In FIG. 1, around the black photoconductor Pk, arranged in the direction of rotation of the photoconductor Pk are a charger CCk as an example of a charging means, an exposure device LPHk as an example of a latent image forming means, a developer Gk as an example of a developing means, a primary transfer roll T1k as an example of a primary transfer means, and a photoconductor cleaner CLk as an example of a cleaning means for an image holding means. Similarly, around the other photoconductors Py, Pm, Pc, Po, there are arranged chargers CCy, CCm, CCc, CCo, exposure devices LPHy, LPHm, LPHc, LPHo, developers Gy, Gm, Gc, Go, primary transfer rolls T1y, T1m, T1c, T1o, and photoconductor cleaners CLy, CLm, CLc, CLo. Toner cartridges Ky, Km, Kc, Kk, and Ko, which are an example of a developer storage means, are detachably supported on the upper portion of the marking portion U1a. The toner cartridges Ky to Ko store developers to be replenished to the developing units Gy to Go.

[0024] An intermediate transfer belt B, which is an example of intermediate transfer means and an example of image holding means, is disposed below each of the photoconductors Py-Po. The intermediate transfer belt B is sandwiched between the photoconductors Py-Po and the primary transfer rolls T1y-T1o. The back surface of the intermediate transfer belt B is supported by a drive roll Rd, which is an example of drive means, a tension roll Rt, which is an example of tension applying means, a walking roll Rw, which is an example of meandering prevention means, a plurality of idler rolls Rf, which are an example of driven means, a backup roll T2a, which is an example of opposing means for secondary transfer, a plurality of retract rolls R1, which are an example of movable means, and the primary transfer rolls T1y-T1o. On the surface of the intermediate transfer belt B, a belt cleaner CLB as an example of a cleaning means for the intermediate transfer means is disposed near the drive roll Rd.

[0025] A secondary transfer roll T2b, which is an example of a secondary transfer member, is disposed opposite the backup roll T2a with the intermediate transfer belt B sandwiched therebetween. A contact roll T2c, which is an example of a contact means, is in contact with the backup roll T2a in order to apply a voltage of a polarity opposite to the charging polarity of the developer to the backup roll T2a. The backup roll T2a, the secondary transfer roll T2b, and the contact roll T2c constitute a secondary transfer device T2 as an example of a secondary transfer means in Example 1. The primary transfer rolls T1y to T1o, the intermediate transfer belt B, the secondary transfer device T2, and the like constitute transfer devices T1, B, and T2 as an example of a transfer means in Example 1.

[0026] Below the secondary transfer device T2, a paper feed tray TR1 as an example of a storage means is provided. Recording paper S as an example of a medium is stored in the paper feed tray TR1. A pickup roll Rp as an example of a take-out means and a handling roll Rs as an example of a handling means are arranged diagonally above the right of the paper feed tray TR1. A transport path SH along which the recording paper S is transported extends from the handling roll Rs. A plurality of transport rolls Ra as an example of a transport means for transporting the recording paper S downstream are arranged along the transport path SH. A deburring device Bt, which is an example of a means for removing unnecessary parts, is disposed downstream of the separation roll Rs. The deburring device Bt pinches the recording paper S with a preset pressure and conveys it downstream to remove unnecessary parts from the edge of the recording paper S, i.e., removes burrs.

[0027] A double feed detector Jk is disposed downstream of the deburring device Bt. The double feed detector Jk measures the thickness of the recording paper S passing through and detects a state in which multiple sheets of recording paper S are overlapped, i.e., a double feed. A correction roll Rc, which is an example of a position correction means, is disposed downstream of the double feed detection device Jk. The correction roll Rc corrects the inclination of the recording paper S with respect to the transport direction, that is, the skew. A registration roll Rr is disposed downstream of the correction roll Rc as an example of an adjustment means for adjusting the timing of conveying the recording paper S to the secondary transfer device T2. Also, a sheet guide SG1 is disposed downstream of the registration roll Rr as an example of a medium guiding means. The feeder unit U2 also has paper feed trays TR2 and TR3 configured similarly to the paper feed tray TR1, pickup roll Rp, handling roll Rs, and transport roll Ra, and the transport path SH from the paper feed trays TR2 and TR3 merges with the transport path SH of the printer main body U1 upstream of the double feed detection device Jk.

[0028] A plurality of conveyor belts HB, which are an example of a medium conveying means, are disposed downstream of the secondary transfer roll T2b in the conveying direction of the recording paper S. A fixing device F, which is an example of a fixing means, is disposed downstream of the conveyor belt HB in the conveying direction of the recording paper S. In the reading unit U3 downstream of the fixing device F, an inspection device IS as an example of a reading means is disposed.

[0029] A transport path SH is formed downstream of the inspection device IS. The transport path SH extends toward the purge unit U4. A reversing path SH2, which is an example of a transport path that branches off from the transport path SH, is formed downstream of the inspection device IS. A first gate GT1, which is an example of a transport direction switching means, is disposed at the branch point between the transport path SH and the reversing path SH2. A plurality of transport rolls Ra, which are an example of a transport means, are disposed on the reversing path SH2. A turn-back path SH4 for reversing, or switching back, the conveying direction of the recording paper S is disposed downstream of the reversing path SH2 and below the fixing device F. A switch-back roll Rb, which is an example of a conveying means capable of rotating forward and backward, is disposed on the turn-back path SH4. A third gate GT3, which is an example of a conveying direction switching means, is disposed at the entrance of the turn-back path SH4. The transport path SH downstream of the return path SH4 merges with the transport path SH for the paper feed tray TR1.

[0030] In the purge unit U4 downstream of the inspection device IS, a relay path SH6 is formed as an example of a conveying path. The relay path SH6 is formed in a U-shape that bends downward and then upward. The length of the relay path SH6 in the first embodiment is set so that the time required for the recording paper S to pass through the relay path SH6 is longer than the time required for the inspection process in the inspection device IS to be completed. In other words, the time required for the inspection process to be completed can be secured before the recording paper S reaches the downstream end of the relay path SH6. A downstream connection path SH7, which is an example of a transport path, is connected to the downstream side of the relay path SH6 and extends toward the buffer unit U5. A first bypass path SH8, which is an example of a direct path, connects the upstream end SH6a and the downstream end SH6b of the relay path SH6. A purge path SH9, which is an example of a discharge path, branches upward from the first bypass path SH8. A purge tray 1, which is an example of a discharge means, is installed at the downstream end of the purge path SH9.

[0031] A fourth gate GT4 and a fifth gate GT5, which are an example of a conveying direction switching means, are disposed at the upstream end SH6a and the downstream end SH6b of the relay path SH6, respectively. Also, a sixth gate GT6, which is an example of a conveying direction switching means, is disposed at the branching portion of the purge path SH9. When inspection of the image on the recording paper S is performed, the fourth gate GT4 is switched so that the recording paper S is transported to the relay path SH6. When inspection is not performed, the fourth gate GT4 is switched so that the recording paper S is transported to the first bypass path SH8. Furthermore, the fifth gate GT5, which is an example of a switching means, is switched so that the recording paper S that has passed the inspection (inspection OK) is transported toward the buffer unit U5. The fifth gate GT5 and the sixth gate GT6 are switched so that the recording paper S that has failed the inspection (inspection NG) is sent to the purge tray 1.

[0032] The buffer unit U5, which is an example of a temporary storage means, has a buffer upstream path SH11, which is an example of a transport path. The buffer upstream path SH11 is connected to the downstream connection path SH7. A plurality of buffer trays 2A, 2B, 2C, and 2D, which are an example of a temporary storage section, are arranged in the buffer unit U5. Buffer entrance paths SH12A, SH12B, SH12C, and SH12D branch off from the buffer upstream path SH11 and extend to the buffer trays 2A to 2D. Gates GT7, GT8, GT9, and GT10, which are an example of a conveying direction switching means, are arranged at the branching points of the conveying paths SH11, SH12A to SH12D. A buffer feed roll 3 as an example of a sending means is disposed at the lower downstream side of each of the buffer trays 2A to 2D. The buffer feed roll 3 in the first embodiment sends out the bottommost recording paper S, i.e., the first recording paper S, from among the stacks of recording paper S loaded on the buffer trays 2A to 2D.

[0033] The recording paper S fed from each buffer paper feed roll 3 is transported through buffer discharge paths SH13A, SH13B, SH13C, and SH13D. The buffer discharge paths SH13A to SH13D merge into a buffer downstream path SH14. The buffer downstream path SH14 extends toward the finisher U6. The buffer upstream path SH11 and the buffer downstream path SH14 are connected to each other by a second bypass path SH16, which is an example of a direct path. In the first embodiment, when the recording paper S is stored in the buffer trays 2A to 2D, the gates GT7 to GT10 are switched depending on the storage destination. When the recording paper S is not stored in the buffer trays 2A to 2D, the seventh gate GT7 is switched so that the recording paper S is sent to the second bypass path SH16.

[0034] The finisher U6 has a top tray 11 as an example of a loading means, an end stitching device 12 as an example of a first post-processing means, and a saddle stitching device 13 as an example of a second post-processing means. The top tray 11 is discharged and stacked with the recording paper S without performing post-processing. The end stitching device 12 can staple the end of the recording paper S with a stapler, or discharge multiple sheets of recording paper S with their edges aligned without stapling. The saddle stitching device 13 can staple the center of the recording paper S with a stapler, fold it in two, and discharge it. The finisher U6 is not limited to the configuration shown in the example. For example, a finisher having a function of forming punch holes or a function of folding in three (so-called Z-fold or C-fold) can be used as an example of post-processing.

[0035] (Marking action) When the printer U receives image information transmitted from the personal computer PC via the print image server COM, a job, which is an image forming operation, is started. When the job is started, the photoconductors Py-Po, the intermediate transfer belt B, etc. rotate. The photoconductors Py to Po are rotated by a driving source (not shown). A preset voltage is applied to the chargers CCy to CCo, which charge the surfaces of the photoconductors Py to Po. The exposure devices LPHy to LPHo, which are an example of a latent image forming device and an example of a light emitting device, output light to write a latent image in response to a control signal from the control unit C, and write an electrostatic latent image on the charged surfaces of the photoconductors Py to Po. The developing units Gy to Go develop the electrostatic latent images on the surfaces of the photoconductors Py to Po. The toner cartridges Ky-Ko replenish the developer consumed in the development in the developing units Gy-Go.

[0036] A primary transfer voltage having a polarity opposite to the charge polarity of the developer is applied to the primary transfer rolls T1y to T1o, and the primary transfer rolls transfer the visible images on the surfaces of the photoconductors Py to Po onto the surface of the intermediate transfer belt B. The photoconductor cleaners CLy to CLo remove and clean the developer remaining on the surfaces of the photoconductors Py to Po after the primary transfer. When passing through the primary transfer area facing the photoconductors Py to Po, the intermediate transfer belt B has images transferred and stacked in the order of O, Y, M, C, and K, and passes through the secondary transfer area Q4 facing the secondary transfer device T2. In the case of a monochrome image, an image of only one color is transferred and sent to the secondary transfer area Q4.

[0037] The pickup roller Rp feeds out the recording paper S from the paper feed trays TR1 to TR3 from which the recording paper S is supplied, depending on the size of the received image information, the designation of the recording paper S, and the size and type of the stored recording paper S. The separation roll Rs separates and separates the recording papers S sent out from the pickup roll Rp one by one. The deburring device Bt applies a preset pressure to the recording paper S passing therethrough to remove burrs. The double feed detector Jk detects double feed of the recording paper S by detecting the thickness of the recording paper S passing through. The correction roll Rc corrects the skew by bringing the passing recording paper S into contact with a wall surface (not shown).

[0038] The registration roll Rr feeds the recording paper S in time with the image on the surface of the intermediate transfer belt B being sent to the secondary transfer area Q4. The sheet guide SG1 guides the recording paper S sent out by the registration roll Rr to the secondary transfer area Q4. In the secondary transfer device T2, a secondary transfer voltage having the same polarity as the charge polarity of the developer set in advance is applied to the backup roll T2a via the contact roll T2c, and the image on the intermediate transfer belt B is transferred to the recording paper S. The belt cleaner CLB removes and cleans the developer remaining on the surface of the intermediate transfer belt B after the image has been transferred in the secondary transfer area Q4. The conveyor belt HB conveys the recording paper S, onto which the image has been transferred by the secondary transfer device T2, downstream while holding the recording paper S on its surface.

[0039] The fixing device F has a heating roll Fh as an example of a heating member and a pressure roll Fp as an example of a pressure member. A heater h as an example of a heat source is housed inside the heating roll Fh. The fixing device F heats and presses the recording paper S passing through a fixing area Q5 where the heating roll Fh and the pressure roll Fp come into contact with each other, thereby fixing an unfixed image on the surface of the recording paper S. The heating roll Fh and the pressure roll Fp constitute the fixing members Fp, Fh of the first embodiment. The inspection device IS reads the image on the recording paper S that has passed through the fixing device F and inspects the image for defects, that is, performs a so-called inspection. When double-sided printing is to be performed on the recording paper S that has passed through the inspection device IS, the first gate GT1 is activated and the paper is transported to the reversal path SH2, switched back at the return path SH4, and sent again through the transport path SH to the registration roll Rr, where printing on the second side is performed.

[0040] (Description of the control unit of the first embodiment) FIG. 3 is a functional block diagram of the control unit according to the first embodiment. In FIG. 3, the control unit (controller) C, which is an example of a control means of the printer U, has an input / output interface I / O that inputs and outputs signals from and to the outside. The control unit C also has a ROM (read-only memory) in which programs and information for performing necessary processing are stored. The control unit C also has a RAM (random access memory) for temporarily storing necessary data. The control unit C also has a CPU (central processing unit) that performs processing according to the programs stored in the ROM or the like. Therefore, the control unit C in the first embodiment is composed of a small information processing device, a so-called microcomputer. Therefore, the control unit C can realize various functions by executing programs stored in the ROM or the like. The control unit C in the first embodiment receives a signal from the signal output element and outputs a signal to the controlled element to control it.

[0041] (Description of signal output elements) The control unit C receives signals from signal output elements such as the user interface UI, the inspection device IS, paper sensors (not shown) on the transport paths SH to SH16, paper detection sensors (not shown) on the buffer trays 2A to 2D, and other sensors (not shown). The user interface UI inputs the contents input by the user or the worker to the control unit C. In the first embodiment, when an input as to whether or not to perform inspection is made through the user interface UI, a control signal is input to the control unit C. When performing inspection, the inspection device IS inputs an image read by the inspection device IS to the control unit C.

[0042] (Description of controlled element) The control unit C outputs signals to a power supply circuit E, the gates GT1 to GT10, the transport rolls on each of the transport paths SH to SH16, and other controlled elements (not shown). The power supply circuit E controls the charging bias of the chargers CCy to CCo, the developing bias of the developers Gy to Go, the primary transfer bias of the primary transfer rolls T1y to T1o, the secondary transfer bias of the secondary transfer roll T2b, and power supply to the heater of the fixing device F, etc. The gates GT1 to GT10 switch the destination of the recording paper S depending on whether or not inspection is required and the storage destination of the recording paper S among the buffer trays 2A to 2D.

[0043] (Function of control unit C) The control unit C of the first embodiment has the following functional means (functional modules, program modules) C1 to C5. A job control means C1 as an example of an image forming control means controls a job which is an image forming operation. The job control means C1 controls the rotation of the photoconductors Py-Po and the intermediate transfer belt B, and controls the application of voltage via a power supply circuit E to form an image corresponding to an original image input from a personal computer PC. The job control means C1 of the first embodiment has a reprint control means C1a and a reservation signal transmission means C1b.

[0044] The reprint control means C1a, which is an example of a reforming means, reprints the image of the page that has been judged as NG when the image of the recording paper S read and inspected by the inspection device IS is unsuitable (inspection NG). Reprinting is performed when the job control means C1 receives a reprint signal sent from the inspection means (C3) described below. If the reprinted image again fails inspection, it is reprinted a third time and this is repeated until it is judged as OK.

[0045] When the third reprinting and subsequent printings (hereinafter simply referred to as "third reprinting") are performed, the reservation signal transmitting means C1b transmits a signal to reserve one of the buffer trays 2A-2D that is available as a tray for storing the third-reprinted recording paper S. That is, when the third reprinting is performed, there is a risk that the preceding recording paper S will use the buffer trays 2A-2D and there will be a shortage of buffer trays 2A-2D before the third-reprinted recording paper S reaches the buffer trays 2A-2D, so in the first embodiment, when a page is to be third-reprinted, the buffer trays 2A-2D for storing the third-reprinted recording paper S are secured early.

[0046] The paper identification information storage means C2 assigns and stores paper identification information for each printed recording paper S. In the first embodiment, for each printed recording paper S, information such as the identification number of the recording paper S, job identification information, the number of pages and the total number of pages, inspection OK or NG, and whether or not reprinting is performed is stored. The job information can use the identification information assigned to each job, and different identification information is registered for each job, such as a preceding job (e.g., "job 1") and a subsequent job (e.g., "job 2"). Each job may involve image formation of only one image, or may involve image formation of a set of multiple images. For information on whether or not reprinting is performed, reprint information (e.g., first reprint) is registered for the recording paper S that has been reprinted by the reprint control means C1a, and information on second reprinting is registered for the third reprint.

[0047] The inspection means C3 inspects the image formed on the recording paper S based on the original image formed by the marking unit U1a and the read image by the inspection device IS. That is, the original image is compared with the read image, and if the similarity is equal to or greater than a predetermined degree by image analysis or image recognition, the inspection is deemed OK, and if the similarity is insufficient due to color unevenness, missing images, paper wrinkles, etc., the inspection is deemed NG. Since various conventionally known techniques can be used for the image analysis, detailed explanations are omitted. The inspection means C3 of the first embodiment has an inspection result registration means C3a and a reprint signal transmission means C3b.

[0048] The inspection result registration means C3a registers and updates the inspection results of the inspection means C3 in the paper identification information of the paper identification information storage means C2. The reprint signal transmission unit C3b transmits a reprint signal to the job control unit C1 when the inspection result of the inspection unit C3 is NG. In the first embodiment, the reprint signal includes, for example, the corresponding job information, page information, and reprint information.

[0049] The discharge control means C4 controls the purge unit U4 to discharge the recording paper S that has failed the inspection to the purge tray 1. The discharge control means C4 controls the recording paper S that has passed the inspection to be transported toward the buffer unit U5. Therefore, the discharge control means C4 in the first embodiment controls the rotation of the transport rolls Ra on the transport paths SH6 to SH9 and the switching of the gates GT4 to GT6 according to the inspection result.

[0050] Figure 4 is an explanatory diagram of an example of the storage and ejection of recording paper in the buffer tray of Example 1, where Figure 4A is an explanatory diagram of a case in which recording paper that fails inspection occurs in the first job but does not fail inspection in the second job, and Figure 4B is an explanatory diagram of a case in which up to the third job is executed after the first job is reprinted. Figure 5 is an explanatory diagram of another example of the storage and ejection of recording paper in the buffer tray of Example 1, where Figure 5A is an explanatory diagram of the case where multiple recording papers fail inspection in a first job, and Figure 5B is an explanatory diagram of the case where a second job is executed after Figure 5A. Figure 6 is an explanatory diagram of yet another example of the storage and ejection of recording paper in the buffer tray of Example 1. Figure 6A is an explanatory diagram of the case where multiple recording papers fail inspection in the first job, similar to Figure 5A. Figure 6B is an explanatory diagram of the case where inspection fails even when reprinted after Figure 6A. Figure 6C is an explanatory diagram of the case where inspection is OK after the third reprint.

[0051] The storage control means C5 controls the buffer unit U5 to control the storage of the recording paper S and the sending out to the finisher U6. The storage control means C5 of the first embodiment includes a storage destination switching means C5a, a tray identification information storage means C5b, a tray reservation means C5c, a page alignment determination means C5d, and a sending out control means C5e. In the storage control means C5 of the first embodiment, when inspection is performed, all pages of recording paper S of the job to be inspected are temporarily stored in the buffer trays 2A to 2D. In the first embodiment, the first page of recording paper S is stored in the tray with the smallest tray number selected from the available buffer trays 2A to 2D. For example, if all of the buffer trays 2A to 2D are available, the buffer tray 2A is selected, and if the buffer tray 2A is in use, the buffer tray 2B is selected. If all pages pass inspection, they are stored in the common buffer trays 2A to 2D. Once all pages pass inspection, they are sent out in order by the buffer feed roll 3 to the finisher U6.

[0052] In FIG. 4, if an intermediate page (the second page of the first job in FIG. 4) fails inspection, the first and third pages of the first job are stored in a common buffer tray 2A, and the second page is discharged to the purge tray 1. If the inspection results are known after the start of the second job, the reprinting of page 2 of the first job is performed between the second and third jobs, as shown in FIG. 4. Here, if the inspection results of the second job are all OK for all pages, the second job is sent from the stored buffer tray 2B toward the finisher U6. The reprinted page ("1-2 reprint") is stored in a buffer tray 2B different from the first and third pages of the first job. That is, in the first embodiment, the recording paper S (third page) on which the image (second page) that is judged to be inspection NG is formed and subsequent images are formed is stored in the buffer tray 2A (corresponding to the first temporary storage section), and if the re-formed image (second page) is judged to be inspection OK, the recording paper S on which the re-formed image (second page) is formed is stored in the buffer tray 2B (corresponding to the second temporary storage section) different from the buffer tray 2A.

[0053] At this time, all pages of the second job are stored in a buffer tray 2B different from the buffer tray 2A in which the first and third pages of the first job are stored. If all pages of the second job pass inspection before all pages of the first job pass inspection, the second job is sent to the finisher U6 when all pages are gathered on the buffer tray 2B. Therefore, the storage control unit C5 of the first embodiment sends the recording paper S of the subsequent second job to the finisher U6 before the first job in which all pages are not gathered. That is, if there is an image that has been inspected NG in the first job that has been formed in advance, and all images of the subsequent second job are inspected and passed inspection, the recording paper S of the subsequent second job is sent to the finisher U6 first.

[0054] Then, when the reprinted second page of the first job is accommodated in the buffer tray 2B, all pages of the first job are accommodated in one of the buffer trays 2A to 2D. Therefore, each page of the first job is sent toward the finisher U6. At this time, the accommodation control means C5 controls the sending in the order of the first page (buffer tray 2A), the second page (buffer tray 2B), and the third page (buffer tray 2A) so that the page order is not disturbed. That is, in the first embodiment, after the recording paper S (first page) of the image before it is judged as inspection NG is sent to the finisher U6, the recording paper S (second page) of the re-formed image is sent from the buffer tray 2B to the finisher U6, and then the recording paper S (third page) of the image after it is judged as inspection NG is sent from the buffer tray 2A to the finisher U6.

[0055] If the first job has a large total number of pages and pages that have failed inspection are identified relatively quickly, and if the pages are identified as not acceptable before the second job is started, the pages of the first job that have failed inspection are reprinted before the second job, as shown in Fig. 5. At this time, the reprinted pages of the first job (pages 2, 4, and 6) are stored in a buffer tray 2B different from the pages of the first job that have passed inspection from the beginning (pages 1, 3, 5, and 7). Then, when the pages are sent out, the sending is controlled so that the page order is not disturbed, as in the case of Fig. 4.

[0056] In FIG. 6, when a page that has been reprinted in the first job has been inspected and failed again (the fourth page of the first job in FIG. 6B), the third reprint is executed. At this time, if the inspection result of the reprint does not arrive in time for the start of the second job, the third reprint is executed after the printing of the second job, as shown in FIG. 6. In addition, in the first embodiment, when the third reprint is executed, the buffer tray 2D (corresponding to the third temporary storage section) that stores the third reprinted page is reserved. Therefore, the third reprinted page is stored in a buffer tray 2D that is different from the buffer tray 2A that stores pages that have been inspected and the buffer tray 2B that stores the reprinted page from the beginning. Then, when all the pages of the first job are collected, they are sent out from the three buffer trays 2A, 2B, and 2D in order to the finisher U6 so that the page order is not disturbed.

[0057] The storage destination switching means C5a switches between the gates GT7 to GT10 depending on the storage destination of the recording paper S. Therefore, the recording paper S is transported to one of the buffer trays 2A to 2D that is the intended storage destination. The tray identification information storage means C5b, which is an example of a tray management means, stores the tray identification information of the buffer trays 2A to 2D. In the first embodiment, the identification information of the recording paper S stored in each of the buffer trays 2A to 2D is stored. Therefore, it is possible to manage which recording paper S (such as the third page of the first job) is stored in each of the buffer trays 2A to 2D. It is also possible to manage which of the buffer trays 2A to 2D does not store recording paper S, that is, which buffer trays 2A to 2D are empty.

[0058] When the tray reservation means C5c receives a reservation signal from the reservation signal transmission means C1b, it reserves an empty buffer tray 2A-2D from among the buffer trays 2A-2D as a tray for the third re-printing. The tray reservation means C5c in the first embodiment performs the reservation by registering the tray for the third re-printing as "scheduled for use" in the tray identification information. Therefore, the accommodation control means C5 controls the feeding so that recording paper S other than the recording paper S for the third re-printing is not fed into or accommodated in the reserved buffer trays 2A-2D. The page alignment determination unit C5d determines whether all pages that have passed inspection for each job have been accommodated in any of the buffer trays 2A to 2D, that is, whether all pages have been aligned, based on the tray identification information. The delivery control means C5e controls the buffer paper feed rolls 3 of the respective buffer trays 2A to 2D to deliver the recording paper S from each of the buffer trays 2A to 2D for a job for which all pages have been prepared, without disturbing the page order.

[0059] (Explanation of the flow chart of the first embodiment) Next, the flow of control in the printer U of the first embodiment will be described with reference to a flow chart. In addition, since the process of switching each gate GT4 to GT6 in the purge unit U4 depending on whether the destination of the recording paper S is the purge tray 1 or not, the process of updating the paper identification information at any time depending on changes in the situation, and the process of updating the tray identification information at any time depending on changes in the situation are simple, flowchart illustrations and detailed explanations are omitted. (Explanation of the image formation flow chart) FIG. 7 is a flowchart of an image forming process in the marking unit of the first embodiment. 7 is performed according to a program stored in the control unit C. This processing is performed in parallel with various other processing of the printer U, such as the processing in the purge unit U4. The flowchart shown in FIG. 7 starts when the printer U is turned on.

[0060] 7, the printer U receives print information and determines whether or not a job has been started. If yes (Y), proceed to ST2. If no (N), repeat ST1. In ST2, printing is executed, and then the process proceeds to ST3. In ST3, it is determined whether the current job is finished. If the answer is yes (Y), the process proceeds to ST4. If the answer is no (N), the process repeats ST3. In ST4, it is determined whether there are any pages to be reprinted. If the answer is yes (Y), the process proceeds to ST5, and if the answer is no (N), the process proceeds to ST8. In ST5, it is determined whether the reprinted page is the third reprint or later. If yes (Y), proceed to ST6, and if no (N), proceed to ST7. In ST6, a tray reservation signal is transmitted, and the process proceeds to ST7.

[0061] In ST7, the following processes (1) and (2) are executed, and then the process returns to ST4. (1) Print the reprint page. (2) A reprint identifier is added to the paper identification information. In ST8, it is determined whether there is a subsequent job. If yes (Y), proceed to ST9, and if no (N), return to ST1. In ST9, the job to be executed is shifted to the succeeding job, and the process returns to ST2.

[0062] (Explanation of the inspection process flow chart) FIG. 8 is a flowchart of the inspection process in the inspection device of the first embodiment. 8 is performed in accordance with a program stored in the control unit C. This processing is performed in parallel with various other processing of the printer U. The flowchart shown in FIG. 8 starts when the printer U is turned on. 8, it is determined whether or not the recording paper S to be inspected reaches the inspection device IS. If the answer is yes (Y), the process proceeds to ST12. If the answer is no (N), the process repeats ST11. In ST12, inspection is performed. That is, the image of the passing recording paper S is read and compared with the original image to determine whether the inspection is OK or NG. Then, the process proceeds to ST13.

[0063] In ST13, it is determined whether the inspection result is OK or not. If it is YES (Y), proceed to ST14. If it is NO (N), proceed to ST15. In ST14, the following processes (1) and (2) are executed, and the process returns to ST11. (1) “Inspection OK” is registered in the paper identification information of the target recording paper S. (2) Set the destination to buffer tray 2A to 2D. In ST15, the following processes (1) and (2) are executed, and then the process returns to ST11. (1) “Inspection NG” is registered in the paper identification information of the target recording paper S. (2) Set the destination to Purge Tray 1.

[0064] (Explanation of the flow chart of the process of storing recording paper in the buffer tray) FIG. 9 is a flowchart of a paper storage process in the buffer unit according to the first embodiment. 9 is performed in accordance with a program stored in the control unit C. This processing is performed in parallel with various other processing of the printer U. The flowchart shown in FIG. 9 starts when the printer U is turned on.

[0065] 9, it is determined whether or not a tray reservation signal has been received. If yes (Y), proceed to ST22. If no (N), proceed to ST23. In ST22, the tray with the smallest tray number among the available buffer trays 2A to 2D is reserved as the tray for accommodating the re-reprinted recording paper S. Then, the process proceeds to ST23. In ST23, it is determined whether the recording paper S conveyed to the buffer trays 2A to 2D has arrived at the buffer unit U5. If no (N), proceed to ST24. If yes (Y), proceed to ST25. In ST24, the seventh gate GT7 is switched to the direct passage (second bypass route SH16) side, and the process returns to ST21.

[0066] In ST25, it is determined from the tray identification information whether or not there is a buffer tray 2A-2D that contains the preceding page of the same job. If the answer is no (N), that is, if the loaded recording sheet S is the first recording sheet S of the job, proceed to ST26. If the answer is yes (Y), that is, if the loaded recording sheet S is the second or subsequent sheet of the job or is a reprint or re-reprint, proceed to ST27. In ST26, the following processes (1) and (2) are executed, and the process returns to ST21. (1) The buffer tray 2A to 2D having the smallest tray number among the available trays is registered in the tray identification information as the buffer tray 2A to 2D to be used for the job. (2) The gates GT7 to GT10 are switched so that the recording paper S is transported to the registered buffer trays 2A to 2D.

[0067] In ST27, it is determined whether the recording paper S conveyed into the buffer unit U5 is a reprinted page. If yes (Y), proceed to ST28. If no (N), proceed to ST31. In ST28, it is determined whether or not there is a buffer tray 2A-2D containing reprinted recording paper S. If yes (Y), proceed to ST30. If no (N), proceed to ST29. In ST29, the following processes (1) and (2) are executed, and then the process returns to ST21. (1) The buffer tray 2A to 2D having the smallest tray number among the available trays is registered in the tray identification information as the buffer tray 2A to 2D that will accommodate the recording paper S that has been reprinted in the job. (2) The gates GT7 to GT10 are switched so that the recording paper S is transported to the registered buffer trays 2A to 2D. In ST30, the gates GT7 to GT10 are switched so that the recording paper S is transported to the buffer trays 2A to 2D that accommodate the recording paper S of the reprinted and preceding pages.

[0068] In ST31, it is determined whether the recording paper S conveyed into the buffer unit U5 is a page that has been reprinted. If yes (Y), proceed to ST32. If no (N), proceed to ST33. In ST32, the gates GT7 to GT10 are switched so that the recording paper S is transported to the buffer trays 2A to 2D for the reserved re-reprinted recording paper S. Then, the process returns to ST21. In ST33, the gates GT7 to GT10 are switched so that the recording paper S is conveyed to the buffer trays 2A to 2D that accommodate the recording paper S of the preceding page of the same job.Then, the process returns to ST21.

[0069] (Explanation of the flow chart of the process of sending out recording paper from the buffer tray) FIG. 10 is a flowchart of the paper sending process in the buffer unit according to the first embodiment. 10 is performed in accordance with a program stored in the control unit C. This processing is performed in parallel with various other processing of the printer U. The flowchart shown in FIG. 10 begins when the printer U is turned on.

[0070] 10, it is determined based on the tray identification information whether or not there is recording paper S stored in the buffer trays 2A to 2D. If yes (Y), proceed to ST42. If no (N), repeat ST41. In ST42, it is determined whether all pages of the oldest job have been stored in one of the buffer trays 2A-2D. That is, based on the information on the total number of pages and the information on the recording paper S stored in each of the buffer trays 2A-2D, if the number of stored sheets of recording paper S matches the total number of pages, it is possible to determine that all pages have been stored, that is, all pages are complete. If yes (Y), proceed to ST43. If no (N), proceed to ST46.

[0071] In ST43, it is determined whether or not there is a buffer tray 2A-2D containing reprinted recording paper S for the oldest job. It is also possible to determine whether or not recording paper S for the oldest job is contained in two or more buffer trays 2A-2D. If the answer is yes (Y), that is, if multiple buffer trays 2A-2D are being used, proceed to ST44. If the answer is no (N), that is, if only one buffer tray 2A-2D is being used, proceed to ST45. In ST44, the recording sheets S are sent out from the multiple buffer trays 2A to 2D toward the finisher U6 so that the page order is not disturbed. Then, the process returns to ST41. In ST45, the recording paper S is sent out from one of the buffer trays 2A to 2D toward the finisher U6 without disturbing the page order, and then the process returns to ST41.

[0072] In ST46, it is determined whether or not all pages of the succeeding job are accommodated in the buffer trays 2A to 2D. If yes (Y), proceed to ST47. If no (N), return to ST42. In ST47, as in ST43, it is determined whether or not there is a buffer tray 2A-2D containing reprinted recording paper S for the subsequent job. If yes (Y), proceed to ST48. If no (N), proceed to ST49. In ST48, the recording sheets S of the succeeding job are sent from the multiple buffer trays 2A to 2D storing the recording sheets S toward the finisher U6 without disturbing the page order. Then, the process returns to ST41. In ST49, the recording sheets S of the succeeding job are sent from one of the buffer trays 2A to 2D storing the recording sheets S toward the finisher U6 without disturbing the page order. Then, the process returns to ST41.

[0073] (Function of Example 1) In the printer U of the first embodiment having the above configuration, even if a page is determined to be unsatisfactory, the subsequent pages are stored in the buffer trays 2A-2D, and the page that failed inspection is stored in a different buffer tray 2A-2D. Therefore, in the buffer trays 2A-2D that stored the page that passed inspection in the first printout, the page that failed inspection is skipped, but when the pages are sent to the finisher U6, they are sent from the multiple buffer trays 2A-2D so that the page order is not disturbed. Therefore, the page order is not disturbed. As described in Patent Documents 1 and 2, in the conventional technology in which only one tray corresponding to the buffer trays 2A to 2D of the present application is provided, if a page that fails inspection occurs, the page order will be disturbed if the subsequent pages are printed first. It is also possible to deal with this by storing pages that pass inspection in one tray and sending pages that fail inspection directly to the finisher U6 without storing them in a tray. In this case, if the reprinted page fails inspection again and needs to be reprinted a third time, further waiting will be required. In addition, if multiple pages that fail inspection occur, the waiting time will be further extended. Therefore, in the conventional technology, there was a problem that the waiting time for the inspection result and the waiting time for reprinting and reprinting were required, and the overall time until image formation was completed was likely to be long.

[0074] In contrast, in the first embodiment, multiple buffer trays 2A to 2D are provided. In the first embodiment, recording paper S that has passed inspection from the beginning and recording paper S to be reprinted can be stored in the multiple buffer trays 2A to 2D. In addition, a subsequent job can be executed before the reprint result is obtained, and the subsequent job is stored in another buffer tray 2A to 2D. Then, when all pages are ready, they can be sent from the multiple buffer trays 2A to 2D to the finisher U6, and the page order is not disturbed. Therefore, the time until image formation is completed can be shortened compared to the conventional technology that has only one tray equivalent to a buffer tray.

[0075] In addition, in the first embodiment, the length of the relay path SH6 is formed to be long, so that the inspection process can be easily completed before the end of the job. Furthermore, in the first embodiment, the recording paper S that fails inspection is discharged to the purge tray 1. Therefore, the user can check the recording paper S that has been discharged to the purge tray 1. Therefore, the recording paper S that fails inspection can be checked.

[0076] Furthermore, in the first embodiment, when reprinting is performed due to inspection failure, if the reprinting is completed in time, it is possible to perform the reprinting before the subsequent job, but if the reprinting is not completed in time, it is also possible to perform the subsequent job first. Then, if the subsequent job has all pages that have been inspected OK first, the subsequent job is sent to the finisher U6 first for processing. Therefore, it is possible to check whether all pages have been completed for each job (each set of multiple images) and to send the pages to the finisher U6. In particular, in the conventional technology described in Patent Documents 1 and 2, if the subsequent job is started before reprinting, it is not impossible to switch jobs if no inspection failure occurs in the subsequent job, but if even one inspection failure occurs in the subsequent job or if reprinting occurs in the preceding job, it is not possible to handle this. Therefore, in the conventional technology, reprinting cannot be performed after the subsequent job, and reprinting must be repeated until all pages of the preceding job are inspected OK. Therefore, there is a problem that the waiting time for the inspection result and the time required for reprinting are required, and the overall time required for image formation to be completed is long. On the other hand, in the first embodiment, it is possible to switch the preceding job with the succeeding job by using the multiple buffer trays 2A to 2D. Therefore, compared with the conventional technology, it is possible to reduce the overall time until the image formation is completed.

[0077] In addition, in the first embodiment, reprinting of the preceding job is not performed in the middle of the subsequent job, but is performed after the subsequent job is completed. Therefore, interruption of the subsequent job is prevented. Therefore, if all the subsequent jobs pass inspection, post-processing of the subsequent job can be performed promptly. Therefore, overall, it also contributes to shortening the time until image formation is completed. In particular, in the first embodiment, recording paper that is inspection-passed from the beginning is stored in one of the buffer trays 2A to 2D. Therefore, if all pages of a subsequent job are inspection-passed from the beginning, they will be stored in one of the buffer trays 2A to 2D. This makes it easier to smoothly execute the sending process and to smoothly execute the switching between the preceding job and the subsequent job.

[0078] Furthermore, in the first embodiment, when third reprinting is performed, the third reprinted recording paper S is stored in a tray different from the reprint buffer trays 2A-2D. Therefore, when the reprinted recording paper S is an intermediate page, it is possible to prevent the reprinted pages and the pages from being stacked out of page order when the reprinted recording paper S is an intermediate page. In particular, even when there are multiple reprinted pages, it is possible to prevent the reprinted recording paper S from being stacked out of page order when the reprinted recording paper S is an intermediate page when the reprinted recording paper S is stacked out of page order ... EXAMPLES

[0079] Next, a second embodiment of the present invention will be described. In the description of the second embodiment, components corresponding to those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted. This embodiment 2 differs from the above-mentioned embodiment 1 in the following points, but is otherwise configured similarly to the above-mentioned embodiment 1.

[0080] FIG. 11 is a block diagram of the second embodiment, and corresponds to FIG. 3 of the first embodiment. 11, in the printer U of the second embodiment, the storage control means C5 of the control section C has an empty tray determination means C5g, a tray search means C5h, and an empty capacity determination means C5i in addition to the means C5a to C5e of the first embodiment. The empty tray determination unit C5g determines whether or not an empty buffer tray 2A-2D (so-called empty tray) exists when the first page of a job is carried in. In the first embodiment, it is possible to determine whether or not an empty tray exists based on the tray identification information. Note that the tray reservation unit C5c in the second embodiment does not accept a tray reservation if an empty tray does not exist even if a tray reservation signal is received.

[0081] When there is no free tray, the tray search unit C5h searches for the buffer tray 2A-2D with the largest free space among the buffer trays 2A-2D in use. The free space (50-10=40 sheets) is calculated by subtracting the number of sheets of recording paper S currently stored (e.g., 10 sheets) from the predetermined maximum capacity (e.g., 50 sheets) of each buffer tray 2A-2D. Then, the buffer tray 2A-2D with the largest free space among the buffer trays 2A-2D is identified. Note that, in the case of the target recording paper S for reprinting, the tray search unit C5h of the first embodiment searches for the buffer tray 2A-2D that stores the recording paper S of the preceding job, because if the reprinted recording paper S is stored in the buffer tray 2A-2D that stores the recording paper S of the same job even if it has the largest free space, the page order will be disturbed. The free space determination means C5i determines whether the free space of the buffer trays 2A-2D searched by the tray search means C5h has reached the number of sheets of recording paper S to be stored. In other words, if the delivered recording paper S is the first page of a subsequent job, it determines whether the total number of pages of the subsequent job is equal to or less than the free space. If the delivered recording paper S is recording paper S for reprinting, it determines whether the number of pages to be reprinted is equal to or less than the free space.

[0082] (Explanation of the flow chart of the second embodiment) Next, the flow of control in the printer U of the second embodiment will be described with reference to a flow chart. In the second embodiment, the image formation process, the inspection process, and the process of sending out from the buffer tray are the same as those in the first embodiment, so the description thereof will be omitted. (Explanation of the flow chart of the process of storing recording paper in the buffer tray) FIG. 12 is a flowchart of a paper storage process in the buffer unit according to the second embodiment. 12, the paper storage process of the second embodiment differs from the paper storage process of the first embodiment shown in FIG 9 only in that ST101 to ST104 are executed between ST25 and ST26, ST105 to ST108 are executed between ST28 and ST29, and ST30 is not executed. Therefore, only the different processes will be described, and the description of the common processes will be omitted.

[0083] 12, it is determined whether or not an empty tray exists. If yes (Y), proceed to ST26. If no (N), proceed to ST102. In ST102, the buffer tray 2A to 2D with the largest free space is searched for, and then the process proceeds to ST103. In ST103, it is determined whether the total number of pages of the job (subsequent job) is equal to or less than the free space. If yes (Y), proceed to ST104. If no (N), there is no tray that can accommodate the job, and the process ends with an error. In ST104, the following processes (1) and (2) are executed, and the process returns to ST21. (1) The buffer tray 2A to 2D with the largest free space is registered in the tray identification information as the tray to be used. (2) The gates GT7 to GT10 are switched so that the recording paper S is conveyed to the tray to be used.

[0084] In ST105, it is determined whether or not an empty tray is present. If yes (Y), proceed to ST29. If no (N), proceed to ST106. In ST106, the buffer tray 2A-2D with the largest free space among the buffer trays 2A-2D storing pages of the preceding job is searched for, and then the process proceeds to ST107. In ST107, it is determined whether the number of reprints is equal to or less than the available capacity. If the answer is yes (Y), proceed to ST108. If the answer is no (N), there is no tray that can accommodate the print job, and the process ends with an error. In ST108, the following processes (1) and (2) are executed, and the process returns to ST21. (1) The buffer tray 2A to 2D with the largest free space is registered in the tray identification information as the tray to be used. (2) The gates GT7 to GT10 are switched so that the recording paper S is conveyed to the tray to be used.

[0085] (Function of Example 2) Figure 13 is an explanatory diagram of an example of the storage and ejection of recording paper in the buffer tray of Example 2, where Figure 13A is an explanatory diagram of the case where recording paper that has been reprinted in the second job is stored in a tray that stores recording paper that has passed inspection from the beginning of the first job, and Figure 13B is an explanatory diagram of the state in which recording paper of the first job has been sent out from the state of Figure 13A. In the printer U of the second embodiment having the above configuration, as shown in the example of FIG. 13, when a third reprint occurs in the first job and a third reprint occurs in the second job, the buffer trays 2A to 2D may be insufficient. Even in this case, even if the recording paper S for the second job's reprint is stored in the buffer tray 2A that stores the recording paper S that has passed inspection from the beginning of the first job, or the recording paper S for the third reprint of the second job is stored in the buffer tray 2B that stores the recording paper S for the first job's reprint, the page order of the sheets sent to the finisher U6 is not disturbed. Therefore, in the second embodiment, as in the first embodiment, it is possible to send the recording paper S from the buffer trays 2A to 2D to the finisher U6 without disturbing the page order. EXAMPLES

[0086] Next, a third embodiment of the present invention will be described. In the description of the third embodiment, components corresponding to those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted. The third embodiment differs from the first embodiment in the following respects, but is otherwise configured in the same manner as the first embodiment.

[0087] FIG. 14 is a block diagram of the third embodiment, and corresponds to FIG. 3 of the first embodiment. 14, the control unit C of the printer U of the third embodiment has a job control unit C1' instead of the job control unit C1 of the first embodiment. Also, the control unit C of the third embodiment has a storage control unit C5' instead of the storage control unit C5 of the first embodiment. The job control means C1' does not have the reservation signal transmission means C1b of the first embodiment. When a job is started, the job control means C1' of the third embodiment executes reprinting until all pages pass inspection. The reprinted pages can be executed in the middle of the job, immediately after the inspection result is known, or can be executed after the job is completed. For example, in the case of a job with a total of 20 pages, if the second page fails inspection, it is possible to reprint the second page between the eighth and ninth pages.

[0088] Figure 15 is an explanatory diagram of an example of the storage and ejection of recording paper in the buffer tray of Example 3, where Figure 15A is an explanatory diagram of the case where the second and fourth pages are reprinted, and Figure 15B is an explanatory diagram of the state in which the reprinted second and fourth pages of recording paper are stored from the state of Figure 15A. The storage control means C5' of the third embodiment does not have the tray reservation means C5c of the first embodiment. When the first page of a job is inspected OK, the storage control means C5' of the third embodiment transports the recording paper S directly to the finisher U6 through the second bypass path SH16 without using the buffer trays 2A to 2D. As long as the inspection is OK for the second and subsequent pages, the recording paper S is transported through the second bypass path SH16. If an inspection NG occurs midway (the second page in FIG. 15), the next page that is inspected OK (the third page in FIG. 15) is stored in one of the buffer trays 2A to 2D (the buffer tray 2A in FIG. 15). As long as the inspection is OK, the recording paper S is stored in that buffer tray (2A). Each time an inspection NG occurs, the buffer trays 2A to 2D are switched. Then, the reprinted recording paper S is stored in the buffer tray (2A) that stores the page (page 3) before the reprinted page (page 4 in FIG. 15) so that the page order is not disturbed. If there is no buffer tray that stores the previous page (page 2 in FIG. 15), the reprinted recording paper S is stored in an empty buffer tray (2C).

[0089] (Explanation of the flow chart of the third embodiment) Next, the flow of control in the printer U of the third embodiment will be described with reference to a flow chart. In the third embodiment, the inspection process and the process of sending out from the buffer tray are the same as those in the first embodiment, and therefore the description thereof will be omitted. (Explanation of the image formation flow chart) FIG. 16 is a flowchart of the image forming process in the marking unit of the first embodiment. 16, the paper storage process of the third embodiment is different from the image forming process of the first embodiment shown in FIG 7 in that the following ST201 and ST202 are executed instead of ST3 to ST6. Therefore, only the different processes will be described, and the description of the common processes will be omitted. 16, it is determined whether or not the job is completed. If the answer is yes (Y), the process proceeds to ST202. If the answer is no (N), ST201 is repeated. In ST202, it is determined whether the inspection result of the inspection device IS for the job being executed is that all pages have passed inspection. If the result is no (N), the process proceeds to ST7, and if the result is yes (Y), the process proceeds to ST8.

[0090] (Explanation of the flow chart of the process of storing recording paper in the buffer tray) FIG. 17 is a flowchart of a paper storage process in the buffer unit according to the third embodiment. 17, the page number n is initialized to 1. That is, n=1 is set. Then, the process proceeds to ST212. In ST212, it is determined whether or not recording paper S has been conveyed into buffer unit U5. If yes (Y), proceed to ST213, and if no (N), repeat ST212. In ST213, it is determined whether the delivered recording paper S is the nth page based on the paper identification information. If the answer is yes (Y), that is, if recording paper S that passed inspection has been delivered consecutively, proceed to ST214. If the answer is no (N), that is, if recording paper S that failed inspection has been discharged to the purge tray 1 and recording paper S with a skipped page number has been delivered to the buffer unit U5, proceed to ST217.

[0091] In ST214, it is determined whether or not there is a buffer tray 2A-2D containing the (n-1)th page. If the answer is no (N), that is, if the inspection has been OK on the first page or continuously from the first page and there is no buffer tray 2A-2D in use, proceed to ST215. If the answer is yes (Y), that is, if an inspection NG occurred midway but inspection has been OK continuously from that point on, proceed to ST216. In ST215, the gate GT7 is switched so that the recording paper S is transported through the second bypass path SH16. Then, the process proceeds to ST218. In ST216, the gates GT7 to GT10 are switched so that the nth page of recording paper S is conveyed to the buffer trays 2A to 2D storing the (n-1)th page.Then, the process proceeds to ST218.

[0092] In ST217, the following processes (1) and (2) are executed, and then the process proceeds to ST218. (1) Among the available buffer trays 2A to 2D, the buffer tray 2A to 2D having the smallest tray number is registered in the tray identification information as the buffer tray 2A to 2D to be used. (2) The gates GT7 to GT10 are switched so that the recording paper S is conveyed to the corresponding buffer trays 2A to 2D. In ST218, it is determined whether the page number n has reached the total number of pages. In other words, it is determined whether the conveyed recording paper S was the last page. If no (N), proceed to ST219. If yes (Y), return to ST211. In ST219, the page number n is incremented by 1. Then, the process returns to ST212.

[0093] (Function of Example 3) In the printer U of the third embodiment having the above configuration, recording paper S that is inspection-passed from the start is sent to the finisher U6 without using the buffer trays 2A-2D. Therefore, compared to the case where the buffer trays 2A-2D are always used, shortages of the buffer trays 2A-2D are suppressed. Also, while waiting for the inspection results to be obtained, subsequent pages are printed and stored in the buffer trays 2A-2D in sequence. Therefore, the time until image formation is completed can be shortened compared to the case where printing of subsequent pages is suspended until the inspection results are obtained. Furthermore, the reprinted recording paper S is stacked in the buffer tray 2A of the previous page. Therefore, compared to a case where the reprinted recording paper S is stored in another buffer tray 2A to 2D, a shortage of the buffer trays 2A to 2D is suppressed, and the page order is not disturbed.

[0094] 15, the reprinted second page is temporarily stored in the buffer trays 2A to 2D, but the present invention is not limited to this. If the second page passes inspection, it can be sent directly to the finisher U6 via the second bypass path SH16.

[0095] (Example of change) Although the embodiments of the present invention have been described above in detail, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Modifications (H01) to (H07) of the present invention are illustrated below. (H01) In the above embodiment, the printer U is shown as an example of an image forming apparatus, but the present invention is not limited to this and may be configured as, for example, a copier, a fax, or a multifunction machine having multiple or all of these functions. Also, the present invention is not limited to an electrophotographic image forming apparatus and may be applied to any image forming apparatus such as an inkjet type or a thermal transfer type.

[0096] (H02) In the above embodiment, the printer U is configured to use five colors of developer, but this is not limited to this and can also be applied to, for example, a monochrome image forming device or a multi-color image forming device having four or less colors or six or more colors. (H03) In the above embodiment, the number of buffer trays 2A to 2D is not limited to four as illustrated, but may be three or less or five or more. (H04) In the third embodiment, the configuration is exemplified where the recording paper S that passes inspection from the first page is not stored in the buffer trays 2A to 2D, but the present invention is not limited to this. It is also possible to store the recording paper S from the first page to the first page that fails inspection in one buffer tray 2A to 2D. (H05) In the above embodiment, it is preferable that the length of the relay line SH6 is the configuration shown in the example, but is not limited to this. It can be arbitrarily changed according to the design, specifications, etc.

[0097] (H06) In the above embodiment, it is desirable to reserve the buffer trays 2A to 2D when third reprinting is performed, but it is also possible to configure in such a way that no reservation is made. (H07) In the above embodiment, it is preferable to provide a purge tray 1, but this is not limiting. It is also possible to use the top tray 11 of the finisher U6 instead of the purge tray 1. In this case, it is possible to transport the recording paper S that has failed inspection to the finisher U6 via the second bypass path SH16.

[0098] (Additional Note) (((1))) A forming means for forming an image on a medium; a reading means for reading the image formed by the forming means; an inspection means for inspecting an image on a medium based on an original image formed by the formation means and an image read by the reading means; a discharge means for discharging a medium on which an image determined to be unsuitable by the inspection means is formed; a temporary storage means having a plurality of temporary storage sections capable of temporarily storing media, the temporary storage section being capable of transporting the media stored in the temporary storage sections toward a post-processing means; the forming means for forming again the image determined to be unsuitable; a storage control means for storing a medium on which an image subsequent to the image determined to be unsuitable is formed in a first temporary storage section which is one of the temporary storage sections, and when the reconstructed image is determined to be suitable, storing the medium on which the reconstructed image is formed in a second temporary storage section different from the first temporary storage section, and, after the medium on which the image prior to the image determined to be unsuitable is formed has been sent to the post-processing means, sending the medium on which the reconstructed image is formed from the second temporary storage section to the post-processing means, and then sending the medium on which the image subsequent to the image determined to be unsuitable is formed from the first temporary storage section to the post-processing means; An image forming apparatus comprising: (((2))) a conveying means disposed between the reading means and the temporary storage means, the conveying means having a conveying path of a length sufficient to ensure the time until the processing by the inspection means is completed; The image forming apparatus according to (((1))) is characterized by comprising: (((3))) the discharge means connected to the downstream side of the conveying path; a switching means for switching a destination of the medium conveyed along the conveying path between the ejection means and the temporary storage means in accordance with an inspection result; The image forming apparatus according to (((2))) is characterized by comprising: (((4))) When forming a plurality of copies of an image, each copy is stored in a different temporary storage unit. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus comprises: (((5))) When forming the image of the plurality of copies, if there is an image that is determined to be unsuitable in the preceding copy of the image formed, and if all the images of the succeeding copy of the image formed are determined to be suitable in the inspection, the succeeding copy of the medium is sent to the post-processing means first. The image forming apparatus according to (((4))) is characterized in that (((6))) The re-formation of the image determined to be unsuitable is performed during the period after the image formation of the preceding copy is completed and before the image formation of the succeeding copy is started. The image forming apparatus according to (((4))) is characterized in that (((7))) When the reconstructed image is inappropriate and the second reconstructed image is appropriate, the second reconstructed medium is stored in a third temporary storage unit different from the first temporary storage unit and the second temporary storage unit. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus comprises: (((8))) The media stored in the first temporary storage unit, the second temporary storage unit, and the third temporary storage unit are sent to the post-processing means in the order of earliest delivery. The image forming apparatus according to (((7))) is characterized in that (((9))) a direct path for conveying the medium from the reading means to the post-processing means without passing through the temporary storage section; Until an image determined to be unsuitable in the inspection occurs, the medium of the image determined to be suitable in the inspection is sent to the post-processing means via the direct path. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus comprises: (((10))) The medium of the image determined to be suitable is stored in one of the plurality of temporary storage units. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus comprises:

[0099] According to the image forming apparatus of (((1))), the time until image formation is completed can be shortened, compared to a conventional configuration having one storage unit that temporarily holds a medium after image formation. According to the image forming apparatus of (((2))), it is possible to ensure the time required for the inspection process to be completed before the product is accommodated in the temporary accommodation means. According to the image forming apparatus of (((3))), media that are not suitable for inspection can be discharged to the discharge means. According to the image forming apparatus of (((4))), it is possible to inspect, store, and send out each copy. According to the image forming apparatus of (((5))), post-processing of the succeeding copy can be performed without waiting for the preceding copy to be reformed, thereby shortening the overall time until image processing is completed. According to the image forming apparatus of (((6))), the preceding copy can be reformed after the preceding copy, and the preceding copy can be processed with priority. According to the image forming device of (((7))), reprinted media and third-reprinted media can be stored and sent out without any disruption in order, compared to when the reprinted media and the third-reprinted media are stored in the same temporary storage section. According to the image forming apparatus of (((8))), even if there is a medium to be reprinted a third time in the middle of a reprinted medium, the medium can be sent to the post-processing device in the correct order by utilizing the third temporary storage section. According to the image forming device of (((9))), the temporary storage unit is prevented from becoming insufficient, compared to a case in which suitable media is not sent out through a direct path. According to the image forming apparatus of (((10))), when a medium determined to be suitable is also stored in the temporary storage section, if all subsequent copies are first determined to be suitable through inspection, the preceding copy can be smoothly replaced with the subsequent copy. [Explanation of symbols]

[0100] 1...Discharge means, 2A~2D: Temporary storage area, 2A…First temporary storage area, 2B: Second temporary housing unit, 2D…Third temporary storage area, C1...forming means, C3: Inspection method, C5… containment control means, GT5...Switching method, IS: reading means, S...medium, SH6: Transport path, SH16…direct passage, U: Image forming device, U4: Means of transportation, U5…Temporary Containment Means.

Claims

1. A forming means for forming an image on a medium; a reading means for reading the image formed by the forming means; an inspection means for inspecting an image on a medium based on an original image formed by the formation means and an image read by the reading means; a discharge means for discharging a medium on which an image determined to be unsuitable by the inspection means is formed; a temporary storage means having a plurality of temporary storage sections capable of temporarily storing media, the temporary storage section being capable of transporting the media stored in the temporary storage sections toward a post-processing means; the forming means for forming again the image determined to be unsuitable; a storage control means for storing a medium on which an image subsequent to the image determined to be unsuitable is formed in a first temporary storage section which is one of the temporary storage sections, and when the re-formed image is determined to be suitable, storing the medium on which the re-formed image is formed in a second temporary storage section different from the first temporary storage section, and, after the medium on which the image prior to the image determined to be unsuitable is formed has been sent to the post-processing means, sending the medium on which the re-formed image is formed from the second temporary storage section to the post-processing means, and thereafter sending the medium on which the image subsequent to the image determined to be unsuitable is formed from the first temporary storage section to the post-processing means; An image forming apparatus comprising:

2. a conveying means disposed between the reading means and the temporary storage means, the conveying means having a conveying path of a length sufficient to ensure the time until the processing by the inspection means is completed; 2. The image forming apparatus according to claim 1, further comprising:

3. the discharge means connected to the downstream side of the conveying path; a switching means for switching a destination of the medium conveyed along the conveying path between the ejection means and the temporary storage means in accordance with an inspection result; 3. The image forming apparatus according to claim 2, further comprising:

4. When forming a plurality of copies of an image, each copy is stored in a different temporary storage unit.

2. The image forming apparatus according to claim 1,

5. When forming the image of the plurality of copies, if there is an image that is determined to be unsuitable in the preceding copy of the image formed, and if all the images of the succeeding copy of the image formed are determined to be suitable in the inspection, the succeeding copy of the medium is sent to the post-processing means first.

5. The image forming apparatus according to claim 4.

6. The re-formation of the image determined to be unsuitable is performed during the period after the image formation of the preceding copy is completed and before the image formation of the succeeding copy is started.

5. The image forming apparatus according to claim 4.

7. When the re-formed image is inappropriate and the re-formed image is appropriate, the re-formed medium is stored in a third temporary storage unit different from the first temporary storage unit and the second temporary storage unit.

2. The image forming apparatus according to claim 1,

8. The media stored in the first temporary storage unit, the second temporary storage unit, and the third temporary storage unit are sent to the post-processing means in the order of earliest delivery.

8. The image forming apparatus according to claim 7,

9. a direct path for conveying the medium from the reading means to the post-processing means without passing through the temporary storage section; Until an image determined to be unsuitable in the inspection occurs, the medium of the image determined to be suitable in the inspection is sent to the post-processing means via the direct path.

2. The image forming apparatus according to claim 1,

10. The medium of the image determined to be suitable is stored in one of the plurality of temporary storage units.

2. The image forming apparatus according to claim 1,

Images