JP2019218163A - Sheet carrying device and sheet carrying control method - Google Patents

Abstract

To provide a sheet carrying device adapted to prevent a damage to a sheet.SOLUTION: A sheet carrying device is adapted to correct a skew of a sheet being transported by carrying means by abutting the sheet against a transport roller pair and forming a deflection in the sheet during transporting the sheet by the carrying means transporting the sheet. In order to aid in forming a deflection, a guide member for guiding an abutment direction of the sheet against the transport roller pair is controlled to be positioned in any of a first position allowed to aid in forming a deflection and a second position not allowed to aid in forming a deflection. In the control, the guide member is controlled so as to be positioned in either the first position or the second position based on information of the sheet.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a sheet conveyance device for conveying a sheet and a sheet conveyance control method.

  In the conventional skew feeding correction device, as disclosed in Patent Document 1, a configuration has been proposed in which a sheet abutting a conveyance roller nip is curved in an S shape in a space formed by a guide member, thereby reducing a conveyance load. I have.

JP 2013-86442 A

  In Patent Literature 1, a sheet is conveyed by bending a sheet into an S shape by a guide member. However, depending on the type of sheet processing, the sheet may need to be passed without skew correction. For example, skew correction is required before normal folding processing. However, in the case of a sheet having a basis weight exceeding the specifications of the folding apparatus, an operation of passing the sheet as it is without performing the folding processing is required. At this time, if the sheet is curved and comes into contact with the guide rollers, the printed sheet surface may be damaged. In particular, the greater the basis weight of the sheet, the more strongly it comes into contact with the guide rollers due to the generated curvature, and the greater the damage to the sheet surface. Further, when the sheet is conveyed by the driving of the conveying roller, the sheet is in contact with the guide rollers, and thus the conveying operation may damage the sheet surface.

  An object of the present invention is to solve such a conventional problem. In view of the above, an object of the present invention is to provide a sheet conveyance device and a sheet conveyance control method that prevent damage to a sheet.

  In order to solve the above-described problems, a sheet conveying device according to the present invention includes a conveying unit that conveys a sheet, and a sheet that is brought into contact with a pair of conveying rollers to form a bend when conveying the sheet by the conveying unit. Correction means for correcting the skew of the sheet conveyed by the conveyance means, and a guide member for guiding the abutting direction of the sheet against the conveyance roller pair to assist in forming the deflection, Control means for controlling the guide member to be positioned at one of a first position where the formation can be assisted and a second position where the formation of the deflection cannot be assisted, and the guide member is controlled based on information of the sheet. It is characterized by having control means for controlling so as to be positioned at any one of the first position and the second position.

  According to the present invention, damage to a sheet can be prevented.

FIG. 1 illustrates a configuration of an image forming system. FIG. 3 is a diagram illustrating a configuration near a roller pair of the sheet skew correction device. FIG. 3 is a block diagram illustrating a control configuration of a sheet skew correction device. 9 is a flowchart illustrating a sheet skew correction process. FIG. 4 is a diagram for explaining a sheet conveyance state. It is a figure for explaining an effect of this embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments do not limit the present invention according to the claims, and all combinations of the features described in the present embodiments are not necessarily essential to the solution of the present invention. . Note that the same components are denoted by the same reference numerals, and description thereof will be omitted.

  FIG. 1 is a diagram illustrating a configuration of an image forming system according to the present embodiment. As shown in FIG. 1, the image forming system includes an image forming apparatus 100, a sheet skew correction apparatus 200, and a post-processing apparatus 300, and performs skew before performing post-processing on a sheet. Corrections can be made. In this embodiment, a copying machine is used as the image forming apparatus 100. A sheet skew correction device is connected to the discharge port of the copying machine, and a post-processing device such as a bookbinding device or a folding machine is further provided downstream of the sheet skew correction device. The image forming apparatus 100 may have various structures such as a copying machine, a printer, and a printing machine. In the present embodiment, a printing apparatus that forms an image on a recording medium such as a sheet by an electrophotographic method is used. It will be described as being used.

  The image forming apparatus 100 includes a paper feed unit 2, a print unit 3, and a paper discharge unit 4 in a casing 1. Further, as shown in FIG. 3, the image forming apparatus 100 includes a control unit 80 that includes a CPU 81, a ROM 82, and a RAM 83, and controls the image forming apparatus 100 in an integrated manner. The control unit 80 is communicably connected to the input unit 90 and the display unit 91, as shown in FIG. The input unit 90 and the display unit 91 are integrated as, for example, an operation panel, and are configured in the image forming apparatus 100. The input unit 90 is, for example, a hard key or a soft key, and receives settings from a user, a job execution instruction, and the like. The display unit 91 is, for example, a touch panel, and displays a user interface screen such as a job execution status and setting contents. The control unit 80 can communicate with the control unit 40 of the sheet skew feeding correction device 200, and performs sheet conveyance control by performing cooperative operations with each other. The sheet conveyance control includes execution control of skew correction of a sheet on which an image has been formed on the sheet.

  A plurality of cassettes 5 corresponding to sheet sizes are prepared in the sheet feeding unit 2, and sheets of the size specified by the control unit based on the job are fed out to the sheet feeding path 6. A registration roller 7 is provided in the paper feed path 6, and the sheet is fed to the downstream printing unit 3 at a predetermined timing after the leading edge alignment is performed.

  The printing unit 3 is provided with an electrostatic drum 10, and a recording unit 9, a developing unit 11, and a transfer charger 12 are arranged around the electrostatic drum 10. The recording unit 9 includes, for example, a laser light emitter, and forms an electrostatic latent image on an electrostatic drum 10 based on image data, and toner ink is adhered to the formed electrostatic latent image by a developing unit 11. Is printed on a sheet by the transfer charger 12. The image printed on the sheet to be printed is fixed by the fixing device 13 and carried out to the paper discharge path 17.

  The paper discharge section 4 is provided with a paper discharge port 14 and a paper discharge roller 15 formed in the casing 1. The circulation path 16 is a conveyance path for reversing the sheet from the sheet discharge path 17 through the switchback path, sending the sheet to the registration roller 7 again, and forming an image on the back surface of the sheet. In this manner, the sheet on which one side or both sides of the image is formed is carried out of the paper discharge port 14 by the paper discharge roller 15.

  The scanner unit 20 optically reads a document image. The scanner unit 20 includes a platen 23 on which a document sheet is placed, a carriage 21 that scans a document image along the platen 23, and an optical reading unit (for example, a CCD device) 22 that photoelectrically converts an optical image from the carriage 21. It is comprised including. Further, an automatic document feeder (ADF: Automatic Document Feeder) 25 continuously feeds a plurality of documents to a reading position on the platen 23. When reading is performed by the automatic document feeder 25, the scanner unit 20 is located below the reading position, and optically reads a continuously fed sheet.

  The sheet skew correction device 200 is connected to the image forming apparatus 100 via the sheet discharge port 14 and performs skew correction of a sheet on which an image is formed. In FIG. 1, the sheet skew correction device 200 can execute skew correction on the sheet before executing post-processing because the post-processing device 300 is connected downstream. .

  A first conveyance roller pair 115 and a second conveyance roller pair 114 are formed on the conveyance path of the sheet skew correction device 200. In the present embodiment, the transport distance from the first transport roller pair 115 to the second transport roller pair 114 is set to about 80 mm. Therefore, the skew correction is performed while the trailing edge of the sheet is nipped by the paper discharge roller 15 of the image forming apparatus 100. With such a configuration, when a jam or the like occurs in the sheet skew correction device 200, the sheet can be easily removed by separating the sheet skew correction device 200 from the image forming apparatus 100.

  The post-processing apparatus 300 is provided with a post-processing path 38 connected to the sheet conveyance path 34 from the sheet skew feeding correction apparatus 200, and a unit that performs post-processing such as folding processing and stapling processing is arranged in the post-processing path 38. The sheet on which the image is formed is supplied from the sheet skew correction device 200 via the sheet conveyance path 34. The post-processing device 300 performs a folding process, a stapling process, and the like on the received sheet, and carries out the sheet to the sheet discharge tray 37. Further, it is possible to discriminate and store the sheet from the image forming apparatus 100 which is not subjected to such post-processing in the discharge tray 37. Although not shown, the post-processing device 300 includes a control unit that includes a CPU, a ROM, and a RAM, and controls the post-processing device 300 as a whole. In the image forming system of FIG. 1, the control unit 80 of the image forming apparatus 100 controls the control unit 40 of the sheet skew correction device 200 and the control unit of the post-processing device 300 to control each device in the image forming system. It can be operated in cooperation.

  FIG. 2 is a diagram illustrating a configuration of the sheet skew correction device 200. The first transport roller pair 115 provided in the transport path is disposed opposite to the first transport lower roller 115b formed of a rubber roller or the like, and the first transport roller 115b that is driven and rotates is disposed to face the first transport lower roller 115b. And an upper roller 115a. The first transport upper roller 115a is pressed against the first transport lower roller 115b by the elastic force of a spring (not shown). The first transport lower roller 115b is connected to a first transport roller drive motor 60 by a first transport drive mechanism (not shown) and is rotatable.

  Like the first transport roller pair 115, the second transport roller pair 114 provided downstream of the first transport roller pair 115 includes a second transport lower roller 114b formed of a rubber roller or the like, and a second transport lower roller 114b. A second transport upper roller 114a that is disposed to face the second transport roller 114b and that is driven to rotate. The second transport upper roller 114a is pressed against the second transport lower roller 114b by the elastic force of a spring (not shown). The second transport lower roller 114b is connected to the second transport roller drive motor 70 by a second transport drive mechanism (not shown) and is rotatable. In the sheet skew correction device 200, the leading end (right end and left end) of the sheet is attached to the nip portion (abutting portion) of the second conveying roller pair 114 which is in reverse rotation to the direction in which the sheet is conveyed, or in the stopped state. The skew of the sheet is corrected by abutting along.

  The nip portion of the first conveying roller pair 115 has a predetermined angle with respect to a conveying surface 130 connecting the first conveying roller pair 115 and the second conveying roller pair 114 so that the sheet is directed to a first guide 118 described later. It is attached. As a result, the leading end of the sheet that has passed through the first conveying roller pair 115 is once conveyed toward the first guide 118 side.

  The first guide 118, together with the second guide 119, forms a loop (bending) for skew correction on the sheet. The first guide 118 and the second guide 119 have inclined surfaces 118a and 119a for guiding the sheet leading end to the nip portion of the second conveying roller pair 114. The end 119b of the second inclined surface 119a is formed immediately before the second conveying roller pair 114. On the other hand, the rotating body (guide roller) 116 at the terminal end of the first inclined surface 118a is located upstream of the terminal end 119b and protrudes from the transfer surface 130 toward the second guide 119 in the transfer direction. The rotator 116 has, for example, a plurality of rotators arranged in the sheet width direction, that is, configured to be parallel to the roller longitudinal direction of the second conveying roller pair 114, and the center axis position thereof is located on the conveying surface 130. It is configured to However, if the outer periphery of the rotating body 116 protrudes from the transport surface 130 toward the second guide 119 so that an optimal loop shape for skew correction can be formed, the position of the center axis is not limited to the above. .

  The first guide 118 interposed between the two transport roller pairs is for regulating the sheet transport direction, and is configured to be bent upward with respect to the transport surface 130. The second guide 119 is for regulating the sheet conveyance direction, and is configured to be bent downward with respect to the conveyance surface 130.

  In the present embodiment, the rotating body 116 is configured to be movable in the vertical direction in the figure by the lifting motor 140. In other words, the rotating body 116 projects to the second guide 119 side from the transport surface 130 as shown in FIG. 2 and the first position at which the loop formation can be assisted, and does not project to the second guide 119 side from the transport surface 130. It is configured to be movable between a first position (retreat position) closer to the first side 118 side. The rotator 116 is controlled to be at the first position before the leading end of the sheet abuts on the rotator 116 to assist in forming a loop on the sheet during skew correction. On the other hand, as will be described later, when the sheet satisfies a predetermined condition, it is determined that the loop formation is not assisted, and the rotator 116 is controlled to be located at the second position where the sheet does not abut.

  In the configuration illustrated in FIG. 2, first, the sheet is conveyed to the first guide 118 side by the first conveying roller pair 115, the direction is changed on the inclined surface 118 a, and the sheet is conveyed to the second guide 119 side. . Thereafter, the sheet is guided by the inclined surface 119b and contacts the nip portion of the second conveying roller pair 114. At this time, the sheet has an S-shape in a guide space formed between the first guide 118 and the second guide 119. In other words, such an S-shape forms a loop for correcting skew of the sheet. The registration sensor 117 is a sensor for detecting the presence or absence of a sheet to be conveyed, and the driving timing of the second conveyance roller pair 114 is controlled based on a detection signal from the registration sensor 117.

  FIG. 3 is a block diagram illustrating a control configuration of the sheet skew correction device 200. The sheet skew correction device 200 includes a control unit 40 that controls the sheet skew correction device 200 as a whole, and the control unit 40 includes a CPU 50, a ROM 51, and a RAM 52. The CPU 50 can communicate with the control unit 80 of the image forming apparatus 100 and the control unit of the post-processing device 300 (not shown). For example, the CPU 50 obtains setting information input via the input unit 90 of the image forming apparatus 100 and transmits information on the presence / absence of a sheet on the conveyance path (jam or the like) to the control unit 80. Further, CPU 50 receives job information from control unit 80 of image forming apparatus 100. The above-described first transport roller drive motor 60, second transport roller drive motor 70, and elevating motor 140 are controlled by the CPU 50. The detection signal from the registration sensor 117 is transmitted to the CPU 50. The CPU 50 controls driving of the second conveying roller pair 114 based on a detection signal from the registration sensor 117.

  FIG. 4 is a flowchart illustrating the sheet skew correction processing according to the present embodiment. 4 is realized, for example, by the CPU 50 loading a program stored in the ROM 51 into the RAM 52 and executing the program.

  In S401, the CPU 50 acquires job information from the control unit 80 of the image forming apparatus 100. Here, the job information is, for example, sheet information, and includes the basis weight and the sheet size of the sheet. The job information may be obtained by the image forming apparatus 100 or may be obtained from an external host PC (not shown). In S402, the CPU 50 drives the elevating motor 140 to move the rotating body 116 to the first position.

  In S403, the CPU 50 determines whether the sheet information satisfies the condition based on the job information acquired in S401. For example, the CPU 50 determines that the condition is not satisfied when the basis weight of the sheet is equal to or less than the predetermined amount, and determines that the condition is satisfied when the sheet weight is larger than the predetermined amount. The CPU 50 may estimate the basis weight of the sheet from the sheet size or the like. If it is determined that the condition is not satisfied in S403, the process proceeds to S405. On the other hand, when it is determined that the condition is satisfied, in S404, the CPU 50 drives the elevating motor 140 to retract the rotating body 116 to the second position. After S404, the process proceeds to S405.

  In S405, the CPU 50 controls the first transport roller driving motor 60 to rotate the first transport roller pair 115, controls the second transport roller drive motor 70, and stops the second transport roller pair 114. Thereafter, in S406, the CPU 50 determines whether or not the detection signal from the registration sensor 117 is on. Here, when it is determined that the detection signal from the registration sensor 117 is on, the process proceeds to S407, and when it is determined that the detection signal is not on, the process of S405 is repeated.

  FIG. 5A is a diagram illustrating a sheet conveyance state at the time when it is determined that the condition is not satisfied in S403 and the process of S405 is executed. Hereinafter, FIGS. 5A to 5E show a case where it is determined in S403 that the condition is not satisfied. As shown in FIG. 5A, before the sheet reaches the registration sensor 117, the first conveying roller pair 115 is rotating and the second conveying roller pair 114 is stopped.

  In S407, the CPU 50 controls the first transport roller driving motor 60 to rotate the first transport roller pair 115, controls the second transport roller drive motor 70, and stops the second transport roller pair 114.

  FIG. 5B is a diagram illustrating the sheet conveyance state at the time when the process of S407 is performed. As shown in FIG. 5B, at a point in time after the sheet has passed the registration sensor 117, the first conveying roller pair 115 is rotating, and the second conveying roller pair 114 is stopped. With such a configuration, a loop is formed in the sheet as the first conveying roller pair 115 continues to rotate. For example, the skew of the sheet is corrected by the left end of the sheet abutting on the nip portion of the second conveying roller pair 114 and the right end of the sheet abutting on the nip portion of the second conveying roller pair 114 later. . FIG. 5C is a diagram illustrating the sheet conveyance state at the time when the skew of the sheet is corrected by the process of S407.

  In S408, the CPU 50 controls the second transport roller driving motor 70 to rotate the second transport roller pair 114. At that time, the CPU 50 controls the second transport roller driving motor 70 to rotate the second transport roller pair 114 when a predetermined time has elapsed since the detection signal of the registration sensor 117 was turned on. Is also good. At this time, the transport speed of the first transport roller pair 115 is controlled to be faster than the transport speed of the second transport roller pair 114. Therefore, a loop is formed in the sheet between the first conveying roller pair 115 and the second conveying roller pair 114 by the rotation of the first conveying roller pair 115 and the second conveying roller pair 114.

  FIG. 5D is a diagram illustrating the sheet conveyance state at the time when the process of S408 is performed. As shown in FIG. 5D, since the sheet is conveyed in a state where a loop is formed, the state where the skew is corrected in S407 is maintained, and the skew occurs due to the passage of the second conveying roller pair 114. Can be prevented.

  In S409, the CPU 50 determines whether or not the detection signal from the registration sensor 117 is off. Here, if it is determined that the detection signal from the registration sensor 117 is off, the processing in FIG. 4 ends. On the other hand, if it is determined that it is not off, the process of S408 is repeated.

  FIG. 5E is a diagram illustrating a sheet conveyance state at the time when the detection signal from the registration sensor 117 is determined to be off in S409. As shown in FIG. 5E, the sheet is conveyed to the post-processing device 300 in the subsequent stage in a state where the skew is corrected. At that time, the CPU 50 may transmit the information that the sheet is conveyed to the post-processing apparatus 300 to the control unit 80 of the image forming apparatus 100.

  FIGS. 5A to 5E show a case where it is determined that the condition is not satisfied in S403, that is, a case where the rotating body 116 is at the first position. If it is determined in S403 that the condition is satisfied, the rotating body 116 is retracted to the second position.

  Hereinafter, the effects of the present embodiment will be described with reference to FIG. In FIG. 6A, when it is determined that the condition is not satisfied in S403, the skew correction is executed by controlling the rotating body 116 to be at the first position, and the second conveying roller pair 114 is determined in S408. Shows the sheet when is rotated. FIG. 6B illustrates a case where the second conveying roller pair 114 is rotated and conveyed while the rotating body 116 is at the first position, even though the sheet information satisfies a predetermined condition. The sheet is shown.

  The sheet in FIG. 6B is a sheet whose sheet information satisfies a predetermined condition, and is, for example, a sheet having a basis weight larger than the predetermined amount. That is, since the rigidity of the sheet is large, the amount of deflection of the sheet becomes smaller than that of the sheet shown in FIG. 6A, and the force with which the sheet comes into contact with the rotating body 116 becomes larger as shown in FIG. 6B. As a result, there is a possibility that the sheet surface on which an image is formed may be damaged (loaded).

  On the other hand, in the present embodiment, when it is considered that the rigidity of the sheet is large, such as when the basis weight of the sheet is larger than the predetermined amount, in S404, the rotating body 116, as shown in FIG. Evacuated to a position. As a result, the sheet is conveyed without abutting on the rotating body 116, so that it is possible to prevent damage to the image-formed sheet surface.

  In FIG. 4, it has been described that the rotating body 116 is retracted to the second position in S404. However, depending on the stiffness of the sheet, the second transport roller pair in the state where the sheet is in contact with the rotating body 116 in S408 is different from the case where the skew correction is performed in the state where the sheet is in contact with the rotating body 116 in S407. It is conceivable that the sheet is conveyed through the sheet 114 to cause greater damage to the sheet. Therefore, even if the sheet is determined to satisfy the condition in S403, the skew correction may be performed in S407 while the rotating body 116 remains at the first position. However, in this case, after the skew correction is performed, the rotating body 116 is retracted to the second position when the second transport roller pair 114 starts rotating.

  Further, in the present embodiment, the two positions of the rotating body 116, the first position and the second position, have been described. However, the position is not particularly limited to two positions, and three or more positions may be configured as the position of the rotating body 116. For example, a plurality of positions capable of assisting loop formation are provided in accordance with sheet information such as the basis weight of the sheet, and the position of the rotating body 116 is controlled so that a load more than necessary for loop formation is not applied to the sheet. You may do it.

  50 CPU: 51 ROM: 52 RAM: 100 Image forming apparatus: 114 Second transport roller pair: 115 First transport roller pair: 116 Rotating body: 118 First guide: 119 Second guide: 140 Elevating motor: 200 Sheet skew Correction device: 300 post-processing device

Claims (11)

Conveying means for conveying the sheet,
Correction means for correcting skew of a sheet conveyed by the conveyance means by abutting the sheet against a conveyance roller pair to form a bend in the sheet when conveying the sheet by the conveyance means,
A guide member that guides the direction in which the sheet abuts against the transport roller pair to assist in the formation of the bend includes a first position capable of assisting the formation of the bend, and a first position capable of assisting the formation of the bend. Control means for controlling the guide member to be positioned at one of the first position and the second position based on information on the sheet. Control means for performing
A sheet conveying device comprising: An acquisition unit for acquiring information on the sheet, further comprising:
The control unit controls the guide member to be positioned at one of the first position and the second position based on the information of the sheet acquired by the acquisition unit. Item 2. The sheet conveying device according to Item 1.   The sheet conveying device according to claim 1, wherein the control unit controls the guide member to be positioned at the second position when information on the sheet satisfies a condition. The information of the sheet is a basis weight,
4. The sheet conveying apparatus according to claim 3, wherein when the basis weight is larger than a predetermined value as the condition, the control unit controls the guide member to be positioned at the second position. 5.   When the information on the sheet satisfies the condition, the control unit controls the guide member to be positioned at the second position before correcting the skew of the sheet by the correction unit. The sheet conveying apparatus according to claim 3, wherein   If the information on the sheet satisfies the condition, the control unit controls the guide member to be located at the second position after correcting the skew of the sheet by the correction unit. Item 5. The sheet conveying device according to item 3 or 4. The guide member is a roller provided so as to be parallel to the transport roller pair,
7. The control device according to claim 1, wherein, as the first position, the outer periphery of the roller is positioned so as to protrude below a nip portion of the transport roller pair. 8. Sheet transport device.   8. The sheet conveying apparatus according to claim 7, wherein the control unit sets the second position so that an outer periphery of the roller does not protrude below the nip portion. 9.   9. The sheet conveying device according to claim 1, wherein the conveying unit conveys the sheet supplied from the image forming apparatus that forms an image on the sheet so that the correcting unit corrects the skew of the sheet. The sheet conveying device according to any one of the above.   The sheet according to claim 1, wherein the conveying unit conveys the sheet whose skew of the sheet has been corrected by the correction unit so as to supply the sheet to a post-processing apparatus. Transport device. A sheet conveyance control method executed in the sheet conveyance device,
A conveying process for conveying the sheet,
A correction step of correcting the skew of the sheet conveyed in the conveyance step by forming a bend in the sheet by abutting the sheet against a conveyance roller pair during conveyance of the sheet in the conveyance step,
A guide member that guides the direction in which the sheet abuts against the transport roller pair to assist in the formation of the bend includes a first position capable of assisting the formation of the bend, and a first position capable of assisting the formation of the bend. A control step of controlling the guide member to be positioned at any one of the first position and the second position based on the information on the sheet when the guide member is positioned at one of the two positions;
And a sheet conveyance control method.

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