JP2012086930A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem wherein, when an image forming device is downsized, a conveyance path length between a register roller for conveying paper to an image forming position and a manual paper feeder is reduced, lateral shift correction by the register roller cannot be smoothly executed, and a case where an image is not formed at a correct position of the paper occurs.SOLUTION: A paper feed part of a manual paper feeder is separated from paper in executing lateral shift correction. The manual paper feeder includes a holding member for holding paper held to a paper feed tray in separating the paper feed part.

Description

  The present invention relates to an image forming apparatus that forms an image on a sheet.

  In an image forming apparatus that forms an image on a sheet, an image may not be formed at a correct position on the sheet due to various factors. For this reason, a technique for forming an image at a correct position on a sheet has been developed.

  The positional deviation of the image on the paper includes a deviation in the conveyance direction of the paper in the image forming apparatus, a deviation in the conveyance width direction perpendicular to the conveyance direction, and an inclination of the image.

  The deviation in the conveyance direction is eliminated by synchronizing the timing of image formation and the timing of paper conveyance.

  The correction of the inclination of the image is removed by correcting the inclination of the conveyed paper. A paper loop is formed upstream of the registration roller by conveying the paper by a predetermined amount after the paper hits the registration roller that conveys the paper to the image forming position, and the paper is conveyed by the registration roller after the loop is formed. Thus, the inclination of the paper is corrected.

  The deviation in the conveyance width direction of the sheet is corrected by moving the registration roller in the axial direction after conveying the sheet to the registration roller.

  Correction of deviations in the sheet conveyance direction and sheet inclination is widely known.

  The shift correction in the paper conveyance width direction is disclosed in Patent Document 1. In Patent Document 1, when the registration roller is moved in the axial direction of the registration roller, in order to enable the sheet to move in the conveyance width direction perpendicular to the conveyance direction, the conveyance roller upstream of the registration roller is used. The paper clamping force is eased.

JP 2007-22680 A

  When the image forming apparatus is downsized, the sheet conveyance path length between the image forming position and the sheet feeding unit that separates and conveys the sheets one by one from the stacked sheets is shortened. When the device is downsized and the paper transport path length is shorter than the length in the paper transport direction, the registration roller is moved in the axial direction to correct the paper transport width direction misalignment, that is, the lateral shift. Even if the paper clamping force of the transport roller upstream of the registration roller is relaxed, the paper cannot be moved in the transport width direction because it is restrained by the paper feed unit that performs the feeding operation. For this reason, the correction of the lateral shift due to the movement of the registration roller is not smoothly performed. In an image forming apparatus provided with a manual sheet feeding device that supplies paper from the side of the image forming apparatus, because the conveyance path length of the sheet feeding conveyance unit from the sheet feeding unit of the manual sheet feeding device to the registration rollers is short, In particular, there is an urgent need to solve the aforementioned problems. In the present specification, the conveyance width direction is a direction in the plane of the sheet to be conveyed and a direction perpendicular to the sheet conveyance direction.

  The present invention solves this problem, smoothly corrects the lateral deviation of the paper, and corrects the inclination of the paper and corrects the lateral deviation sufficiently to form an image forming apparatus that forms an image at the correct position of the paper. The purpose is to provide.

  The object is achieved by the following invention.

1. It has a paper feed tray that holds paper in the stacked state, a paper feed unit that separates and transports the stacked paper into one sheet, and a manual paper feeder that has a pressing member, and a registration roller that transports the paper to the image forming position. A sheet feeding and conveying unit that receives and conveys the sheet from the manual sheet feeding device; and a control unit that controls the registration roller and the sheet feeding unit.
The control unit moves the registration roller in the axial direction of the registration roller to perform lateral deviation correction, and when the lateral deviation correction is performed, separates the paper feeding unit from the paper,
The image forming apparatus, wherein the pressing member presses a sheet held by the sheet feeding tray.

  2. The conveyance path length L2 from the downstream end of the pressing member to the registration roller is longer than the length of the longest sheet in the conveyance direction among the sheets stacked on the sheet feeding tray. The image forming apparatus according to 1.

3. The manual sheet feeding device includes a regulating member that regulates the position of the sheet in the conveyance width direction on the sheet feeding tray.
The conveyance path length L1 from the downstream end of the restriction member to the registration roller is longer than the length of the longest sheet in the conveyance direction among the sheets stacked on the sheet feeding tray. The image forming apparatus according to 1 or 2.

  4). The image according to any one of 1 to 3, wherein the control unit performs lateral deviation correction by moving the registration roller in the axial direction after the leading edge of the sheet has passed the registration roller. Forming equipment.

  5. The sheet feeding / conveying unit includes one or more conveying rollers disposed between the sheet feeding unit and the registration roller, and the downstream end of the regulating member and the most upstream conveying of the conveying rollers. The conveyance path length L3 between the rollers is shorter than the shortest sheet length in the conveyance direction among the sheets stacked on the sheet feeding tray. The image forming apparatus described.

  The image forming apparatus of the present invention separates the sheet feeding unit of the manual sheet feeding device from the sheet and corrects the sheet released from being held by the separation of the sheet feeding unit by the pressing member when the lateral deviation is corrected. As a result, an image is formed at the correct position on the paper during paper feeding from the manual paper feeding device.

1 is a diagram illustrating an entire image forming apparatus according to an embodiment of the present invention. 3 is a front view illustrating configurations of a manual sheet feeding device 14 and a sheet feeding / conveying unit 15. FIG. 3 is a plan view of the manual sheet feeder 14. FIG. It is a figure which shows an example of the pressing member 144 and its support structure. It is a figure which shows the other example of the pressing member 144 and its support structure. FIG. 6 is a perspective view of a manual sheet feeder 14 provided with a pressing member shown in FIG. 5. It is a figure which shows the moving part which moves the registration roller 155 to an axial direction. It is a block diagram of a control system that performs control in manual sheet feeding. 10 is a flowchart of control in manual sheet feeding. 3 is a front view illustrating configurations of a manual sheet feeding device 14 and a sheet feeding / conveying unit 15. FIG. It is a schematic diagram which shows conveyance path length H1-H4.

<Image forming apparatus>
FIG. 1 is a diagram showing an entire image forming apparatus according to an embodiment of the present invention. In the following, a monochrome image forming apparatus will be described, but the present invention is not limited to this and can be applied to a color image forming apparatus.

  The image forming apparatus includes an image forming apparatus main body 10 and a post-processing apparatus 20.

  The image forming apparatus main body 10 includes an automatic document conveying device 11, an image reading unit 12, an image forming unit 13, a manual paper feeding device 14, a paper feeding / conveying unit 15, a lower paper feeding device 16, and a paper discharging unit 17. A refeed unit 18 and an operation display unit 19.

  The automatic document feeder 11 includes a document feed tray 111 and a document discharge tray 112. The document feeder tray 111 conveys the documents stacked on the document feed tray 111 one by one to the document reading position, and the scanned document is discharged to the document. The paper is discharged to the paper tray 112.

  The image reading unit 12 includes a reading unit 121 that reads a document conveyed by the automatic document conveyance device 11, a document table 122 on which the document is placed, and an imaging unit 123 that receives reflected light from the document and reads the document. Have. The image reading unit 12 reads the document conveyed by the automatic document conveying device 11 and the document placed on the document table 122 and outputs an image signal.

  The image forming unit 13 forms an image on the paper P by an electrophotographic process, and includes a drum-shaped photosensitive member 131, a charging device 132, an exposure device 133 that performs dot exposure, a developing device 134, and a transfer device. 135, a cleaning device 137, and a fixing device 136.

  A toner image is formed on the photosensitive member 131 that rotates clockwise by charging, exposure, and development, and the formed toner image is transferred to the paper P at the transfer position as the image forming position formed by the transfer device 135. The The toner image transferred to the paper P is fixed by the fixing device 136.

  The paper P is stored in the three paper feed trays 161 of the lower paper feed device 16 and the manual paper feed device 14 of the side paper feed unit, and is supplied from these paper feed devices to the transfer position for transfer. At the position, the toner image is transferred onto the paper P. The toner image is transferred and the paper P passes through the fixing device 136 and is fixed.

  The sheet P subjected to the fixing treatment is discharged from the paper discharge unit 17 to the post-processing device 20 in the fixing-treated posture, or is reversed to the front and back in the paper discharge unit 17 and then discharged to the post-processing device 20.

  In the double-sided image formation, the paper P on which the toner image is formed on the first surface and passed through the fixing device 136 is transported to the refeed unit 18, transported to the reversing path 136 B, and reversed from the front and back to the refeeding path 18 A. It is conveyed to the transfer position of the image forming unit 13.

  The post-processing device 20 includes a punching processing unit, a binding processing unit, an aligning unit, and the like (not shown). After the post-processing is performed on the paper P, the elevating tray 21, the fixed tray 22 or the lower portion as the main paper discharge unit It is discharged to the tray 23.

  Three sheet feed trays 161 are installed vertically in the lower sheet feed device 16 as a normal sheet feed device that stores regular sheets and feeds paper in normal image formation, and is fed to each sheet feed tray 161. A paper portion 162 is provided.

  The operation display unit 19 has a touch panel 191 and an operator's instruction is given via the touch panel.

<Manual feed>
FIG. 2 is a front view showing the configuration of the manual paper feeder 14 and the paper feeding / conveying section 15, and FIG. 3 is a plan view of the manual paper feeder 14.

  The manual sheet feeding device 14 includes a sheet feeding tray 141 that can be set to a storage position along the side wall of the image forming apparatus and a sheet feeding position that opens almost horizontally, a sheet feeding unit 142, and a conveyance width perpendicular to the conveyance direction. A regulating member 143 that regulates the position of the sheet P in the direction, and a pressing member 144 that presses the sheet P stacked on the sheet feeding tray 141. The paper feed unit 142 includes a pickup roller 142A that feeds the paper P on the paper feed tray 141, a separation roller 142B that separates the paper P into one sheet, and a separation roller 142C, and is stacked on the paper feed tray 141. The paper P is separated into one sheet and sent out.

  The paper feed tray 141 loads and holds the paper P. In the paper holding state shown in FIG. 2, the feeding side end of the paper feed P is inclined with respect to the horizontal so as to face down.

  The paper feed unit 142 feeds the sheets P stacked on the paper feed tray 141 one by one from the top and transports them toward the paper feed transport unit 15 and is supported by a shaft 142D extending in the transport width direction. . That is, the separation roller 142B is fixed to the shaft 142D, and a pair of support arms 142E are rotatably supported. The rotation of the shaft 142D rotates the separation roller 142B, and the rotation of the separation roller 142B is transmitted to the pickup roller 142A by the belt 142F.

  The shaft 142D moves up and down (up and down in FIG. 2). The support arm 142E is locked by a stopper (not shown) so as not to rotate more than a predetermined angle in the clockwise direction in FIG. 2 when the shaft 142D is raised. In the paper feeding position shown in FIG. 2, the pickup roller 142A is in pressure contact with the paper P by the weight of the pickup roller 142A and the weight of the support arm 142E, and rotates to pick up the paper P. When the shaft 142D is raised, the pickup roller 142A and the separation roller 142B are raised and separated from the paper P. Hereinafter, the pickup roller 142 </ b> A and the separation roller 142 </ b> B are lifted and separated from the paper P is referred to as separation of the paper feeding unit 142.

  As shown in FIG. 3, a pair of regulating members 143 are provided at both ends in the conveyance width direction of the paper feed tray 141, and an operator operates one of the regulating members 143 with a known moving mechanism (not shown). By moving in the transport width direction W2, the other regulating member 143 moves in the opposite direction by the same amount and comes into close contact with the edge of the paper P, thereby restricting the position of the paper P in the transport width direction.

  The holding member 144 presses the paper P stacked on the paper feed tray 141 and suppresses the movement of the paper P, and as shown in FIG. 3, the regulating member with which the paper P is in contact with the side edge. It protrudes to the inside of 143 (on the paper P). FIG. 4 shows an example of the pressing member 144 and its support structure. The holding member 144 is fixed to the support member 144A. The support member 144A is guided by the restriction member 143 and can be moved up and down as indicated by an arrow W3, and is biased downward by a spring 144B. The holding member 144 is urged by the spring 144 </ b> B and presses the paper P on the paper feed tray 141.

  When stacking the paper P on the paper feed tray 141, the operator lifts the support member 144 </ b> A to leave a space between the paper feed tray 141 and the pressing member 144. By inserting the paper P at the gap and opening the support member 144A, the pressing member 144 is set at a position where the paper P is pressed.

  Another example of the pressing member 144 is shown with reference to FIGS. FIG. 5 shows another example of the pressing member 144 and its supporting structure, and FIG. 6 is a perspective view of the manual sheet feeder 14 provided with the pressing member of FIG.

  The pressing member 144 is supported by the regulating member 143 so as to be rotatable about the shaft 144C, and is urged by a spring 144B so as to rotate counterclockwise as indicated by an arrow in FIG. Due to the urging of the spring 144B, the pressing member 144 suppresses the free movement of the paper P by pressing the stacked paper P obliquely downward. FIG. 6 shows a state where there is no paper P on the paper feed tray 141. As shown in FIG. 6, the pressing member 144 protrudes from the side surface of the regulating member 143.

  When stacking the paper P on the paper feed tray 141, the operator moves the regulating member 143 in the direction opposite to the white arrow to widen the interval between the two regulating members 143. As a result, the stacking space is expanded and the sheets P can be easily stacked.

  After the paper P is stacked on the paper feed tray 141, the regulating member 143 is moved in the direction of the white arrow and brought into contact with the side edge of the paper P, whereby the paper P is set at the stacking position and the pressing member. 144 is in the state shown in FIG. In the state shown in FIG. 5, the pressing member 144 suppresses the movement of the paper P from which the paper feeding unit 142 is separated.

  The paper feeding / conveying unit 15 transfers the paper P from the lower paper feeding device 16 as a main body paper feeding device that feeds the standard size paper P and the manual paper feeding device 14 to the transfer device 135 of the image forming unit 13 (FIG. 1). A transfer roller 151, 152, 153, a loop roller 154, and a registration roller 155 for conveying the paper P from the lower sheet feeding device 16. Have. The loop roller 154 forms a loop of the paper P upstream of the registration roller 155, and the inclination of the paper P is corrected by this loop. The registration roller 155 conveys the paper P to the transfer position in synchronization with image formation in the image forming unit. By synchronous conveyance by the registration roller 155, an image is formed at a correct position on the paper P in the conveyance direction. The conveyance roller 153, the loop roller 154, and the registration roller 155 are each composed of a driving roller and a driven roller. When the driven roller comes into contact with the driving roller, the conveying roller 153 and the loop roller 154 are in a state of conveying the paper P, and when the driven roller is separated from the driving roller, the paper P can move in the conveying width direction. Become. In this way, the contact or separation between the driving roller and the driven roller is referred to as contact / separation in the following.

  FIG. 7 is a diagram illustrating a moving unit that moves the registration roller 155 in the axial direction of the registration roller 155. The moving unit includes a motor MT4, gears G1, G2, a pinion G3, and a rack G4.

  The registration roller 155 is formed in the unit and is rotatably supported by the unit frame YF. The registration roller 155 is driven and rotated by a motor MT4 through gears G1 and G2 to convey the paper P. The rack G4 fixed to the unit frame YF is driven by the motor MT5 through the pinion G3 and moves in the axial direction of the registration roller 155 indicated by the arrow W2. The motor MT5 is composed of a pulse motor and, as will be described later, performs a controlled amount of rotation by a controlled number of pulses. By rotation of the motor MT5, the unit frame YF and the registration roller 155 move in the axial direction indicated by the arrow W2.

  FIG. 8 is a block diagram of a control system that performs control in manual sheet feeding.

  The control unit CS controls the motors MT1 to MT5 and the solenoids SL1 to SL3 based on signals from the sensors SE1 and SE2.

  The sensor SE1 is disposed at the upstream position of the registration roller 155, and the sensor SE2 is disposed at the downstream position of the registration roller 155. The sensor SE1 detects the passage of the paper P. The sensor SE2 includes a line sensor in which sensor elements constituting the sensor are arranged in parallel in the transport width direction, and detects the position of the side edge of the paper P in the transport width direction.

  The motor MT1 drives the paper feed unit 142, the motor MT2 drives the transport roller 153, the motor MT3 drives the loop roller 154, and the motor MT4 drives the registration roller 155. The motor MT5 moves the registration roller 155 in the axial direction of the registration roller 155 as described above.

  FIG. 9 is a flowchart of control in manual sheet feeding.

  At the start of printing (ST1), the motors MT1 to MT3 are operated, and the paper feed unit 142, the transport roller 153, and the loop roller 154 are operated to feed and transport the paper P from the paper feed tray 141 (ST2). .

  When a predetermined time has elapsed since the detection of the leading edge of the sheet by the sensor SE1 (ST3) (YES in ST4), the motors MT1 to MT3 are stopped (ST5). When the loop roller 154 conveys the sheet P for a predetermined time from the detection of the sheet leading edge of the sensor SE1, a loop of the sheet P is formed upstream of the registration roller 155, and the leading edge of the sheet P is evenly aligned in the conveyance width direction. At 155, the inclination of the paper P is corrected.

  After a predetermined time has elapsed from step ST5, the motors MT3 and MT4 are activated, the loop roller 154 and the registration roller 155 are activated, and the paper P is conveyed toward the transfer position (ST6).

  In step ST7 after a predetermined time has elapsed from ST6, the solenoids SL1 to SL3 are actuated to raise the shaft 142D, whereby the pickup roller 142A and the separation roller 142B are raised, and the transport roller 153 and the loop roller 154 are separated from each other. (ST7). The state at the stage of ST7 is shown in FIG.

  Simultaneously with ST7, in step ST8, the position of the paper P in the transport width direction is detected by the sensor SE2.

  In step ST9, based on the detection signal of the sensor SE2, the motor MT5 is rotated by an amount for correcting the deviation from the normal position of the paper P, and the registration roller 155 is moved in the axial direction of the registration roller 155 to correct the lateral deviation. .

  As shown in FIG. 10, the lateral deviation correction operation in ST9 is performed in ST7 in a state in which the paper feed unit 142 is separated, the holding of the paper P is released, and the transport roller 153 and the loop roller 154 are separated. The lateral shift correction is performed smoothly.

  When the holding of the paper P by the paper feeding unit 142 is canceled and the lateral deviation correction is performed, the paper P stacked and held on the paper feeding tray 141 which is the next paper moves along with the paper P which is laterally corrected and conveyed. In addition, the stacking state of the sheets P on the sheet feeding tray 141 may be lost. The pressing member 144 presses the paper P held by the paper feed tray 141 and prevents such a collapse of the stacked state.

  In order to perform the lateral shift correction smoothly, it is preferable that the regulating member 143 and the pressing member 144 are installed at positions described below.

  In FIG. 11, the regulating member 143 is installed such that the conveyance path length L1 that is the length of the conveyance path from the downstream end of the regulating member 143 to the registration roller 155 is longer than the length Pmax of the paper P (L1> Pmax). ). Various sizes of paper P are stacked on the paper feed tray 141. Regardless of the size of the paper P stacked on the paper feed tray 141, in order to prevent the regulating member 143 from interfering with the movement of the paper P in the transport width direction at the time of lateral deviation correction, the paper P loaded on the paper feed tray 141 is not disturbed. It is preferable that the conveyance path length L1 is longer than the length Pmax of the paper P that is longest in the conveyance direction.

  Similarly, it is preferable that the holding member 144 is installed so that the conveying path length L2 which is the length of the conveying path from the downstream end of the pressing member 144 to the registration roller 155 is longer than the length Pmax of the paper P (L2). > Pmax).

  In order to improve the pressing effect of the pressing member 144, the pressing member 144 is preferably made of a material having a friction coefficient comparable to that of the paper P. The holding member 144 is made of, for example, cork, artificial leather, or a flocked cloth.

  Further, the conveyance path length L3 that is the length of the conveyance path from the downstream end of the regulating member 143 to the conveyance roller 153 is set to be shorter than the length Pmin of the paper P (L3 <Pmin).

  As described above, sheets P of various sizes are stacked on the sheet feeding tray 141. By making the transport path length L3 shorter than the length of the shortest paper P among the papers P stacked on the paper feed tray 141, the paper P is shifted in the transport width direction between the regulating member 143 and the transport roller 153. All the sheets P are transported without shifting in the transport width direction. In the illustrated example, one conveyance roller 153 is installed between the paper feeding unit 142 and the loop roller 154, but a plurality of conveyance rollers are provided between the paper feeding unit 142 and the loop roller 154. In some cases, the conveyance path length L3 is a conveyance path length between the downstream end of the regulating member 143 and the most upstream conveyance roller.

  In the embodiment described above, the lateral deviation correction is performed after releasing the restraint of the paper P in the manual paper feeder 14 by separating the paper feed unit 142 from the paper P regardless of the size of the paper P. Yes.

  However, depending on the size of the paper P, the paper P can be released by selecting the paper feed unit 142, the transport roller 153, or the loop roller 154 as a restraining member and separating the paper P from the paper P. is there. For example, lateral deviation correction control can be performed as follows.

  The length of the sheet P in the conveyance direction is equal to or greater than the conveyance path length L4 from the downstream end of the sheet feeding unit 142, that is, the downstream end of the nip between the separation roller 142B and the separating roller 142C to the upstream end of the nip of the registration roller 155. In this case, that is, for large-size paper, lateral shift correction is performed by moving the registration roller 155 in the axial direction of the registration roller 155 after separating the paper feed unit 142, the conveyance roller 153, and the loop roller 154.

  On the other hand, when the length of the sheet P in the conveyance direction is shorter than the conveyance path length L4 from the downstream end of the nip between the separation roller 142B and the separating roller 142C to the upstream end of the nip of the registration roller 155, That is, for small size paper, only the transport roller 153 and the loop roller 154 are separated, and the paper feed unit 142 is placed in contact with the paper P, and lateral deviation correction is performed.

14 Manual Feeder 15 Feeder Conveying Unit 16 Lower Conveyor 142, 162 Paper Feeder 143 Restricting Member 144 Pressing Member 151, 152, 153 Conveying Roller 154 Loop Roller 155 Registration Roller L1, L2, L3, L4 Conveying Path Length

Claims (5)

A paper feed tray that holds paper in a stacked state, a paper feed unit that separates and transports stacked paper into a single sheet, and a manual paper feeder that includes a pressing member, and a registration roller that transports the paper to the image forming position. A sheet feeding and conveying unit that receives and conveys the sheet from the manual sheet feeding device; and a control unit that controls the registration roller and the sheet feeding unit.
The control unit moves the registration roller in the axial direction of the registration roller to perform lateral deviation correction, and when the lateral deviation correction is performed, separates the paper feeding unit from the paper,
The image forming apparatus, wherein the pressing member presses a sheet held by the sheet feeding tray.   The conveyance path length L2 from the downstream end of the pressing member to the registration roller is longer than the length of the longest sheet in the conveyance direction among the sheets stacked on the sheet feeding tray. Item 2. The image forming apparatus according to Item 1. The manual sheet feeding device includes a regulating member that regulates the position of the sheet in the conveyance width direction on the sheet feeding tray.
The conveyance path length L1 from the downstream end of the restriction member to the registration roller is longer than the length of the longest sheet in the conveyance direction among the sheets stacked on the sheet feeding tray. Item 3. The image forming apparatus according to Item 1 or 2.   The said control part performs lateral deviation correction by moving the said registration roller to the said axial direction after the front-end | tip of a paper passes the said registration roller, The one of Claims 1-3 characterized by the above-mentioned. Image forming apparatus.   The sheet feeding / conveying unit includes one or more conveying rollers disposed between the sheet feeding unit and the registration roller, and the downstream end of the regulating member and the most upstream conveying of the conveying rollers. The conveyance path length L3 between the rollers is shorter than the length of the shortest sheet in the conveyance direction among the sheets stacked on the sheet feeding tray. The image forming apparatus described in 1.

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