JP2021028270A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the continuity of a plurality of print products when an abnormality is detected in a print sheet at a relatively low cost. A line sensor 31 detects the shape of a print sheet at a predetermined inspection position on the upstream side of a print engine 10a in a transfer path of the print sheet. (A) When the shape of the print sheet detected by the line sensor 31 is normal, the control unit 81 causes the sheet transfer unit 10b to transfer the print sheet to a specific discharge destination after passing through the print engine 10a. b) When the shape of the print sheet detected by the line sensor 31 is abnormal, (b1) the print sheet is sent to the sheet transport section 10b to a discharge destination different from the specific discharge destination after passing through the print engine 10a. The image to be printed on the print sheet is printed on the print sheet succeeding the print sheet by the (b2) print engine 10a. [Selection diagram] Fig. 3

Description

The present invention relates to an image forming apparatus.

A certain image forming apparatus is provided with a copying machine and an inspection device at the subsequent stage of the copying machine. When the inspection device detects a sheet abnormality of a print product output from the copying machine, (a) the sheet in which the abnormality has occurred is detected. Is discharged to a specific discharge destination, (b) the subsequent normal sheet is temporarily retained, and the sheet in which the image to be printed on the abnormal sheet is reprinted is discharged and retained. Is subsequently discharged (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2004-20650

However, in the above-mentioned image forming apparatus, since the inspection apparatus is provided on the downstream side of the print engine in the transport path of the print sheet, it takes time from the time of printing until the sheet abnormality is detected, and a plurality of sheets are used. In order to maintain the continuity of the print product, it is necessary to provide a mechanism for temporarily retaining the subsequent normal sheet as described above, which increases the cost of the apparatus.

The present invention has been made in view of the above problems, and an object of the present invention is to obtain an image forming apparatus that maintains the continuity of a plurality of print products when an abnormality is detected in a print sheet at a relatively low cost. To do.

The image forming apparatus according to the present invention includes an image sensor that detects the shape of a print sheet on which an image is printed, a print engine that prints the image on the print sheet, and the print sheet along a predetermined transport path. It includes a sheet transporting unit that transports the sheet to the print engine and transports the print engine to a predetermined discharge destination, and a control unit that controls the sheet transporting unit and the print engine. Then, the image sensor detects the shape of the print sheet at a predetermined inspection position on the upstream side of the print engine in the transport path, and the control unit (a) of the print sheet detected by the image sensor. When the shape is normal, the print sheet is transported to a specific discharge destination after passing through the print engine by the sheet transport unit, and (b) the shape of the print sheet detected by the image sensor is abnormal. In some cases, (b1) the sheet transport unit is made to transport the print sheet to a discharge destination different from the specific discharge destination after passing through the print engine, and (b2) the print engine is transferred to the print sheet. The image to be printed is printed on a print sheet following the print sheet.

According to the present invention, it is possible to obtain an image forming apparatus that maintains the continuity of a plurality of print products when an abnormality is detected in a print sheet at a relatively low cost.

The above or other object, feature and superiority of the present invention will be further clarified from the following detailed description with the accompanying drawings.

FIG. 1 is a side view illustrating the mechanical internal configuration of the image forming apparatus according to the embodiment of the present invention. FIG. 2 is a plan view of the image forming apparatus shown in FIG. FIG. 3 is a block diagram showing an electrical configuration of the image forming apparatus 10 according to the embodiment of the present invention. FIG. 4 is a flowchart illustrating the operation of the image forming apparatus shown in FIGS. 1 to 3.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a side view illustrating the mechanical internal configuration of the image forming apparatus according to the embodiment of the present invention. FIG. 2 is a plan view of the image forming apparatus shown in FIG.

The image forming apparatus 10 according to this embodiment is an apparatus such as a printer, a copier, a facsimile machine, a multifunction device, and the like, and includes a line-type inkjet color printing mechanism in this embodiment.

The image forming apparatus 10 shown in FIG. 1 includes a print engine 10a and a sheet conveying unit 10b. The print engine 10a physically prints an image to be printed on a print sheet (print paper or the like). The sheet transport unit 10b transports the print sheet before printing to the print engine 10a along a predetermined transport path, and transports the print sheet after printing from the print engine 10a to a predetermined discharge destination.

In this embodiment, the print engine 10a includes line-type inkjet recording units 1a to 1d corresponding to four ink colors of cyan, magenta, yellow, and black. As shown in FIG. 2, in this embodiment, each of the inkjet recording units 1a, 1b, 1c, and 1d has a plurality of (here, three) head units 11. The head portions 11 are arranged along the main scanning direction and are removable from the apparatus main body. The number of head units 11 of each of the inkjet recording units 1a, 1b, 1c, and 1d may be one.

The sheet transport section 10b includes a main sheet transport section 10b1 and a circulation sheet transport section 10b2.

In this embodiment, the main sheet transport unit 10b1 includes an annular transport belt 2 arranged to face the print engine 10a and transports the print sheet, a drive roller 3 and a driven roller 4 on which the transport belt 2 is suspended. A suction roller 5 for nipating a print sheet together with a transport belt 2 and discharge rollers 6, 6a and 6b are provided.

The drive roller 3 and the driven roller 4 orbit the transport belt 2. Then, the suction roller 5 nips the print sheet conveyed from the paper feed cassettes 20-1 and 20-2, which will be described later, and the nipped print sheet is moved to the print position of the inkjet recording units 1a to 1d by the transfer belt 2. The images are conveyed in order, and images of each color are printed by the inkjet recording units 1a to 1d. Then, the print sheet after the color printing is completed is discharged to the discharge trays 10c1, 10c2 and the like by the discharge rollers 6, 6a and 6b.

The image forming apparatus includes at least two discharge trays 10c1 and 10c2, and the print sheet is discharged to the first discharge tray 10c1 by the discharge roller pair 6a or to the second discharge tray 10c2 by the discharge roller pair 6b. It is discharged.

Further, the main sheet transport unit 10b1 includes a plurality of paper feed cassettes 20-1 and 20-2. The paper feed cassettes 20-1 and 20-2 accommodate the print sheets 101 and 102, and the lift plates 21 and 24 push the print sheets 101 and 102 upward to bring them into contact with the pickup rollers 22 and 25. The print sheets 101 and 102 placed on the paper feed cassettes 20-1 and 20-2 are picked up one by one from the upper side by the pickup rollers 22 and 25 to the paper feed rollers 23 and 26. The paper feed rollers 23 and 26 are rollers for transporting the print sheets 101 and 102 fed from the paper feed cassettes 20-1 and 20-2 by the pickup rollers 22 and 25 one by one onto the transport path.

The transport roller 27 is a transport roller on a transport path common to the print sheets 101 and 102 transported from the paper feed cassettes 20-1 and 20-2.

The resist roller 28 suspends the conveyed print sheets 101 and 102, and conveys the printed sheets 101 and 102 to the print engine 10a at the secondary paper feeding timing. The secondary paper feed timing is designated by the control unit 81 described later so that the image is formed at the designated position on the print sheets 101 and 102.

At the time of double-sided printing, the circulation sheet transport unit 10b2 returns the print sheet from a predetermined position on the downstream side of the print engine 10a to the upstream side from the inspection position of the line sensor 31 described above.
The circulation sheet transport unit 10b2 includes a transport roller 41 and a switchback transport path 41a that reverses the traveling direction of the print sheet in order to switch the surface of the print sheet facing the print engine 10a from the first surface to the second surface.

Further, the image forming apparatus 10 includes a line sensor 31 and a sheet detection sensor 32.

The line sensor 31 is arranged at a predetermined position on the transport path of the print sheet along the direction perpendicular to the transport direction of the print sheet, and detects the shape of the print sheet on which the image is printed (that is, the transported print sheet). It is an optical image sensor. For example, the line sensor 31 is a CIS (Contact Image Sensor). The line sensor 31 detects the two-dimensional shape of the print sheet by sequentially detecting the shape (one-dimensional shape) of each position in the sub-scanning direction of the conveyed print sheet in the main scanning direction.

In this embodiment, the line sensor 31 is arranged between the resist roller 28 and the print engine 10a in the transfer path of the print sheet. That is, the line sensor 31 detects the shape of the print sheet at a predetermined inspection position on the upstream side of the print engine 10a in the transport path of the print sheet.

The sheet detection sensor 32 is an optical sensor that detects that the tips of the printed sheets 101 and 102 have passed a predetermined position on the transport path.

FIG. 3 is a block diagram showing an electrical configuration of the image forming apparatus 10 according to the embodiment of the present invention. As shown in FIG. 3, the image forming apparatus 10 includes an image output unit 71 having a mechanical configuration as shown in FIGS. 1 and 2, as well as an operation panel 72, a storage device 73, and an arithmetic processing unit 74. Be prepared. The image output unit 71 includes the above-mentioned line sensor 31 and sheet detection sensor 32.

The operation panel 72 is arranged on the surface of the housing of the image forming apparatus 10, includes a display device such as a liquid crystal display, and an input device such as a hard key and a touch panel, and displays various messages to the user on the display device. The user operation is detected by the input device.

The storage device 73 is a non-volatile storage device (flash memory, hard disk drive, etc.) that stores data, programs, and the like necessary for controlling the image forming device 10.

The arithmetic processing unit 74 includes a computer that operates according to a program, an ASIC (Application Specific Integrated Circuit) that executes a predetermined operation, and the like, and operates as various processing units. The computer is equipped with a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., loads a program stored in the ROM, the storage device 73, etc. into the RAM, and executes the program on the CPU. As a result, it operates as various processing units (with ASIC if necessary).

Here, the arithmetic processing unit 74 operates as a control unit 81 and an image processing unit 82.

The control unit 81 controls the image output unit 71 (print engine 10a, sheet transfer unit 10b, etc.) and executes the print job requested by the user. In this embodiment, the control unit 81 causes the image processing unit 82 to perform predetermined image processing, controls the head unit 11 to eject ink, and forms a printed image on the print sheet. The image processing unit 82 executes predetermined image processing such as RIP (Raster Image Processing), color conversion, and half toning on the image data of the image to be printed on the print sheet, and generates the print image data. In the case of double-sided printing, the image processing unit 82 executes the above-mentioned predetermined image processing on the image to be printed on the first side of the print sheet and the image to be printed on the second side of the print sheet. One-sided print image data and second-sided print image data are generated.

In particular, the control unit 81 determines whether or not the shape of the print sheet detected by the line sensor 31 is normal, and (a) if the shape of the print sheet detected by the line sensor 31 is normal, the sheet. When the print sheet is conveyed to the specific discharge destination (for example, the discharge tray 10c1) after passing through the print engine 10a by the transport unit 10b, and (b) the shape of the print sheet detected by the line sensor 31 is abnormal, (b) b1) The sheet transport unit 10b conveys the print sheet to a discharge destination (for example, discharge tray 10c2) different from the specific discharge destination after passing through the print engine 10a, and (b2) prints on the print sheet on the print engine 10a. The image to be printed is printed on a print sheet that follows the print sheet.

Here, for example, if any of the four corners of the print sheet is broken, a part of the outer edge portion of the print sheet is torn and chipped, or the print sheet has holes, the shape of the print sheet is abnormal. Is determined to be. In other words, if the shape of the print sheet is a quadrangle with the size specified by the request of the print job and there is no chip inside, it is judged that the shape of the print sheet is normal, and if not, it is printed. It is determined that the shape of the sheet is abnormal.

In this embodiment, if an abnormality in the shape of the print sheet is detected before the start of printing the image on the print sheet in the print engine 10a, the control unit 81 does not execute the printing in the print engine 10a. The sheet transport unit 10b is made to transport the print sheet to the other discharge destination described above. Further, in this embodiment, when an abnormality in the shape of the print sheet is detected after the start of printing the image on the print sheet in the print engine 10a, the control unit 81 immediately stops printing in the print engine 10a and the sheet. The transport unit 10b is made to transport the print sheet to the other discharge destination described above.

Further, when double-sided printing is specified for the print job and double-sided printing is executed on the print sheet, the control unit 81 prints the first side of the print sheet without detecting a shape abnormality, and then the print engine 10a. The print sheet is advanced to the circulation sheet transport section 10b2 by controlling a flap (not shown) or the like at a predetermined transport path branch position in the subsequent stage. In the case of double-sided printing, the control unit 81 determines whether or not the shape of the print sheet detected by the line sensor 31 on both the first side and the second side of the print sheet is abnormal. That is, the shape of the print sheet is detected by the line sensor 31 at the timing before the start of printing on the first side of the print sheet and the timing before the start of printing on the second side after the completion of printing on the first side of the print sheet. Will be done. Since there is a possibility that an abnormality in the shape of the print sheet may occur in the circulation sheet transport unit 10b2, the shape of the print sheet is detected even before the start of printing on the second surface.

Then, in the case of double-sided printing, when (a) the control unit 81 determines that the shape of the print sheet detected by the line sensor 31 on the first side of the print sheet is abnormal, the control unit 81 executes printing on the second side. Instead, the sheet transport unit 10b was made to transport the print sheet to the other discharge destination described above, and (b) it was determined that the shape of the print sheet detected by the line sensor 31 on the second surface of the print sheet was abnormal. Occasionally, the sheet transport unit 10b is made to transport the print sheet to the other discharge destination described above.

Further, in the case of double-sided printing, when it is determined that the shape of the print sheet detected by the line sensor 31 on the second side of the print sheet is abnormal after printing on the first side, the control unit 81 determines that the shape of the print sheet is abnormal. The image printed on the first side of the print sheet is printed again on the first side of the print sheet following the print sheet, and the image to be printed on the second side of the print sheet is printed on the subsequent print sheet of the print sheet. Print on the second side of.

In this case, the first-side print image data and the second-side print image data described above are stored in a RAM, a storage device 73, or the like after they are generated, and the control unit 81 stores the above-mentioned first side print image data in the print engine 10a. An image based on the surface print image data is printed on the first surface of the print sheet, and the print engine is made to print the image based on the above-mentioned second surface print image data on the second surface of the print sheet. Then, after the printing of the first side is completed, the control unit 81 holds the first side print image data until it is determined that the shape of the print sheet is not abnormal for the second side of the print sheet, and then, for example, the first side. The one-sided print image data and the second-sided print data are collectively erased from the RAM, the storage device 73, or the like.

Next, the operation of the image forming apparatus will be described. FIG. 4 is a flowchart illustrating the operation of the image forming apparatus shown in FIGS. 1 to 3.

First, when the control unit 81 receives a request for a print job (including a copy job), the control unit 81 starts a print job, causes the image processing unit 82 to perform predetermined image processing, and causes the sheet transport unit 10b to perform a print sheet. The transfer is started (step S1).

After the transfer of the print sheet is started, the print sheet reaches the resist position, and when the image processing is completed, the print sheet is conveyed from the resist position to the print engine 10a.

Then, when the print sheet reaches the above-mentioned inspection position, the shape of the print sheet is detected by the line sensor 31, and one-dimensional image data (for example, binarized image data) indicating the shape of each line is sequentially generated by the control unit 81. Will be sent to. The control unit 81 determines whether or not the shape of the print sheet is normal based on the data (step S2). When a shape abnormality occurs in the print sheet at the tip end portion or the intermediate portion of the print sheet in the traveling direction, the control unit 81 detects the abnormality before all the shapes of the print sheet are detected, and detects the abnormality in the print sheet. It is determined that the shape of is not normal (abnormal). That is, when the shape abnormality is not detected up to the rear end portion of the print sheet in the traveling direction, it is determined that the shape of the print sheet is normal.

On the other hand, in synchronization with the timing when the print sheet passes through the print engine 10a, the control unit 81 controls the print engine 10a based on the image data, and causes the print engine 10a to print the image on the print sheet.

Then, when it is determined that the shape of the print sheet is normal, the control unit 81 conveys the printed print sheet to a specific discharge destination (for example, discharge tray 10c1) specified by a job request or the like (step S3). ).

After that, the control unit 81 determines whether or not the print job is completed (step S4), returns to step S2 until the print job is completed, and executes the same processing for the subsequent print sheet. At that time, the subsequent transport of the print sheet may be started before the printing of the print sheet is completed.

On the other hand, when it is determined that the shape of the print sheet is not normal (abnormal), the control unit 81 stops printing the corresponding page image on the print sheet (step S5), and the sheet transport unit 10b The print sheet is conveyed to a discharge destination (for example, discharge tray 10c2) different from the designated discharge destination (for example, discharge tray 10c1) (step S6), and the print engine 10a is used for subsequent (next) printing. The page image is printed on the sheet (step S7).

If a shape abnormality has also occurred in the subsequent print sheet, the subsequent print sheet is also transported to another discharge destination in the same manner, and the page is transferred to the subsequent print sheet having a normal shape. The image is printed.

As described above, according to the above embodiment, the line sensor 31 detects the shape of the print sheet on which the image is printed. The print engine 10a prints an image on a print sheet. The sheet transport unit 10b transports the print sheet to the print engine 10a and also transports the print sheet from the print engine 10a to a predetermined discharge destination along a predetermined transport path. Then, the line sensor 31 detects the shape of the print sheet at a predetermined inspection position on the upstream side of the print engine 10a in the transport path, and the control unit 81 has (a) the shape of the print sheet detected by the line sensor 31. If it is normal, the sheet transport unit 10b is allowed to transport the print sheet to a specific discharge destination after passing through the print engine 10a, and (b) if the shape of the print sheet detected by the line sensor 31 is abnormal, ( b1) The sheet transport unit 10b is made to transport the print sheet to a discharge destination different from the specific discharge destination after passing through the print engine 10a, and (b2) the print engine 10a is made to print an image to be printed on the print sheet. Print on the print sheet that follows the print sheet.

As a result, the shape of the print sheet is inspected on the upstream side of the print engine 10a, and if an abnormality is detected in the shape, the print sheet is immediately discharged to another discharge destination and printed on the subsequent print sheet. Is continued, and only the print generation part of the print sheet with a normal shape is ejected to the specified ejection destination, so that the printing is not interrupted and is specified by the print job at the specified ejection destination. All print products are obtained on a normal print sheet. Therefore, the continuity of a plurality of print products at the time of detecting an abnormality in the print sheet is maintained at a relatively low cost.

It should be noted that various changes and modifications to the above-described embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without leaving the intent and scope of the subject and without diminishing the intended benefits. That is, it is intended that such changes and amendments are included in the claims.

For example, in the above embodiment, the print engine 10a is an inkjet type print engine, but may be a print engine of another type (for example, an electrophotographic method).

The present invention can be applied to, for example, an image forming apparatus such as a printer or a multifunction device.

10 Image forming device 10a Print engine 10b Sheet transfer unit 10b2 Circulation sheet transfer unit 10c1, 10c2 Discharge tray (example of discharge destination)
81 Control unit 82 Image processing unit

Claims (4)

An image sensor that detects the shape of the print sheet on which the image is printed, and
A print engine that prints the image on the print sheet,
A sheet transport unit that transports the print sheet to the print engine and from the print engine to a predetermined discharge destination along a predetermined transport path.
The sheet transport unit and the control unit that controls the print engine are provided.
The image sensor detects the shape of the print sheet at a predetermined inspection position on the upstream side of the print engine in the transport path.
When the shape of the print sheet detected by the image sensor is normal, the control unit causes the sheet transport unit to transport the print sheet to a specific discharge destination after passing through the print engine. , (B) When the shape of the print sheet detected by the image sensor is abnormal, (b1) the sheet transport unit is sent to a discharge destination different from the specific discharge destination after passing through the print engine. The print sheet is conveyed, and (b2) the print engine is made to print an image to be printed on the print sheet on a print sheet succeeding the print sheet.
An image forming apparatus characterized by. When an abnormality in the shape of the print sheet is detected after the start of printing the image on the print sheet, the control unit immediately stops the printing and prints the image on the sheet transport unit to the other discharge destination. The image forming apparatus according to claim 1, wherein the sheet is conveyed. The sheet transport unit includes a circulation sheet transport unit that returns the print sheet from a predetermined position on the downstream side of the print engine to the upstream side from the inspection position during double-sided printing.
When the control unit executes double-sided printing on the print sheet, whether or not the shape of the print sheet detected by the image sensor on both the first surface and the second surface of the print sheet is abnormal. When (a) it is determined that the shape of the print sheet detected by the image sensor on the first surface is abnormal, the sheet transport unit does not perform printing on the second surface. When the print sheet is conveyed to the other discharge destination and (b) it is determined that the shape of the print sheet detected by the image sensor on the second surface is abnormal, the sheet transfer unit receives the print sheet. The print sheet is conveyed to the other discharge destination, and the print engine prints the image printed on the first surface of the print sheet on the first surface of the subsequent print sheet of the print sheet. An image to be printed on the second side of the sheet is printed on the second side of the print sheet following the print sheet.
The image forming apparatus according to claim 1 or 2. An image processing unit that executes predetermined image processing to generate first-side print image data and second-side print image data is further provided.
The control unit (a) causes the print engine to print an image based on the first side print image data on the first side of the print sheet, and causes the print engine to print an image based on the second side print image data. The first side of the print sheet is printed, and (b) after the printing of the first side is completed, the first side of the print sheet is formed until it is determined that the shape of the print sheet is not abnormal. Retaining surface print image data,
3. The image forming apparatus according to claim 3.

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