JP2010047415A - Paper passage change-over device, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the occurrence of colliding noises between paper and a change-over member and damage to the paper by damping impact between the end of the paper and the change-over member when changing over the carrying direction of the paper. <P>SOLUTION: A belt 36 of a change-over gate 31 is generally arranged at a branch point between a paper discharge passage and a reverse passage in a direction changeable manner. It is rotated in the carrying direction of the paper to change the moving direction of the paper when the paper abuts thereon. When the front end of the paper abuts on the belt 36, the moving direction of the paper is changed, thus damping collision between the paper and the change-over gate 31. This reduces the occurrence of colliding noises between the paper and the change-over gate 31 and damage to the paper. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sheet path switching apparatus and an image forming apparatus that switch a sheet conveyance path to a first conveyance path that performs normal sheet discharge or a second conveyance path that performs duplex printing or reverse sheet discharge.

  Conventionally, when switching the path of a sheet to be conveyed, a claw-shaped switching guide made of resin or the like has been used. For example, FIG. 11 is a schematic diagram illustrating a route switching example of the switching guide 60 according to the conventional example. The switching guide 60 shown in FIG. 11 is rotated in two directions by a solenoid around a rotation shaft 60a.

  When the paper P is transported to the normal paper discharge path 60c in the first direction, the switching guide 60 is rotated to the position indicated by the broken line. Further, when the paper P is transported to the reversing path 60d in the second direction, the switching guide 60 is rotated to the position indicated by the solid line. When the paper P is transported to the reversing path 60d, the leading edge of the paper P abuts against the curved portion 60b of the switching guide 60 and changes the traveling direction while sliding the leading edge of the paper P along the curved shape of the curved portion 60b. change.

  In relation to such a conventional example, Patent Document 1 discloses a sheet conveying apparatus. According to this sheet conveying apparatus, the switching claw for switching the sheet conveyance path and the stepping motor for driving the switching claw are provided.

JP 2006-240862 A (FIG. 4)

  However, when the leading edge of the paper hits the switching claw, the paper switching claw described in the conventional example and Patent Document 1 may be damaged by the impact at that time, such as corner breakage. In addition, there is a problem that a paper collision sound is generated by an impact when the paper hits the switching claw and feels harsh.

  Even if the portion where the sheet abuts is formed in a curved shape, the traveling direction of the leading edge of the sheet is not always constant, and the leading edge of the sheet may be damaged such as corner breakage. Further, in the case of a paper with a large curl, there is a problem in that the paper does not follow the curved shape of the switching claw and a paper feeding failure such as a paper jam occurs.

  Therefore, the present invention solves such a problem related to the conventional example, and enables the shock of the edge of the sheet and the switching member to be buffered when the conveyance direction of the sheet is switched. It is an object of the present invention to provide a sheet path switching device and an image forming apparatus that can reduce the occurrence of a collision sound of a switching member and damage to the sheet.

  In order to solve the above problem, a paper path switching device according to claim 1 is a paper path switching device that switches a paper transport path to a first transport path or a second transport path, wherein the first transport path and the first transport path A switching member disposed at a branching point of the second transport path so as to be freely switchable and rotating in the same direction as the transport direction of the paper and contacting the paper to change the traveling direction of the paper, and switching the direction of the switching member A switching drive unit, an operation unit for setting the sheet conveyance path to the first conveyance path or the second conveyance path, and a control unit for controlling the switching drive unit based on path information set by the operation unit Are provided.

  According to the paper path switching device of the first aspect, when the paper transport direction is switched, the end of the paper is brought into contact with the switching member that rotates in the same direction as the transport direction to change the traveling direction of the paper. The collision between the edge of the sheet and the switching member can be buffered. As a result, it is possible to reduce the occurrence of collision noise between the paper and the switching member and damage to the paper.

  In order to solve the above-described problem, a paper path switching device according to a second aspect of the present invention is the paper path switching device according to the first aspect, wherein the switching member is disposed on the inner side of the belt with which the paper abuts and has a switching surface. And a rotation support member for forming the belt into a shape and rotatably supporting the belt. According to the paper path switching device of the second aspect, the end of the paper is brought into contact with the switching surface of the belt rotatably supported by the driven rotation support member to change the traveling direction of the paper. The collision between the end portion and the switching member can be buffered.

  In order to solve the above-described problem, a paper path switching device according to a third aspect is the invention according to the second aspect, wherein the rotation drive unit that rotates the belt, the upstream side of the branch point of the first transport path and the second transport path. And a detection unit that detects a sheet and outputs a detection signal to the control unit, and the control unit controls the rotation driving unit to rotate in the conveyance direction of the sheet based on the detection signal. It is characterized by doing. According to the paper path switching device of the third aspect, the end of the paper is brought into contact with the belt rotated in the paper transport direction by the rotation driving unit to change the paper traveling direction. The collision with the switching member can be buffered.

  In order to solve the above problem, a paper path switching device according to a fourth aspect of the present invention is a paper path switching device that switches a paper transport path to a first transport path or a second transport path. A switching member that is disposed at a branch point of the second transport path so as to be capable of switching the direction, and has a belt that rotates in the same direction as the transport direction of the paper and that contacts the paper and changes the traveling direction of the paper; A rotation drive unit for rotating the belt and switching the direction of the belt, an operation unit for setting the sheet conveyance path to the first conveyance path or the second conveyance path, and path information set by the operation unit And a control unit for controlling the rotation driving unit based on the above. According to the paper path switching device according to the fourth aspect, since the direction of the belt is switched by the rotation driving unit that rotates the belt, the number of parts can be reduced.

  In order to solve the above-described problem, an image forming apparatus according to a fifth aspect is an image forming apparatus that switches a conveyance path of a sheet on which an image is formed to a first conveyance path or a second conveyance path. The image forming unit to be formed and the direction of the first transport path and the second transport path are arranged so as to be switchable in direction, and rotate in the same direction as the transport direction of the paper on which the image is formed by the image forming unit. A switching member that changes the traveling direction of the paper when the paper abuts, a switching drive unit that switches the direction of the switching member, and an operation for setting the paper transport path to the first transport path or the second transport path And a control unit that controls the switching drive unit based on path information set by the operation unit.

  According to the image forming apparatus of the fifth aspect, when the paper transport direction is switched, the end of the paper is brought into contact with the switching member that rotates in the same direction as the transport direction, so that the traveling direction of the paper is changed. The collision between the edge of the sheet and the switching member can be buffered. As a result, it is possible to reduce the occurrence of collision noise between the paper and the switching member and damage to the paper.

  According to the paper path switching device and the image forming apparatus according to the present invention, the switching member that is disposed so as to be capable of switching the direction at the branch point of the first transport path and the second transport path rotates in the paper transport direction and the paper is The advancing direction of the paper is changed by contact.

  With this configuration, when the paper transport direction is switched, the collision between the edge of the paper and the switching member can be buffered. As a result, it is possible to reduce the occurrence of collision noise between the paper and the switching member and damage to the paper.

  Hereinafter, embodiments of a paper path switching device and an image forming apparatus according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to this embodiment.

  FIG. 1 is a schematic diagram illustrating a configuration example of an image forming apparatus 100 according to the present invention. An image forming apparatus 100 illustrated in FIG. 1 includes an image forming unit GH, an image reading device YS, and the like. The image forming unit GH is referred to as a tandem color image forming unit, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, an intermediate transfer member 6, a secondary transfer unit 7A, and the like.

  An image reading device YS including an automatic document feeder 501 and a scanning exposure device 502 is installed above the image forming unit GH. The document d placed on the document table of the automatic document feeder 501 is transported by the transport unit, and an image on one or both sides of the document is scanned and exposed by the optical system of the scanning exposure device 502 and read by the line image sensor CCD. .

  The image signal photoelectrically converted by the line image sensor CCD is subjected to analog processing, A / D conversion, shading correction, image compression processing and the like in the image processing unit, and then sent to the exposure units 3Y, 3M, 3C, and 3K. It is done.

  The image forming unit 10Y that forms a yellow (Y) image includes a charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, a primary transfer unit 7Y, and a cleaning unit 8Y around a drum-shaped photoreceptor 1Y. An image forming unit 10M that forms a magenta (M) color image includes a charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer unit 7M, and a cleaning unit 8M around a drum-shaped photoreceptor 1M. An image forming unit 10C for forming a cyan (C) color image has a charging unit 2C, an exposure unit 3C, a developing unit 4C, a primary transfer unit 7C, and a cleaning unit 8C around a drum-shaped photoconductor 1C. An image forming unit 10K that forms a black (Bk) image includes a charging unit 2K, an exposure unit 3K, a developing unit 4K, a primary transfer unit 7K, and a cleaning unit 8K around a drum-shaped photoconductor 1K. The charging unit 2Y and the exposure unit 3Y, the charging unit 2M and the exposure unit 3M, the charging unit 2C and the exposure unit 3C, and the charging unit 2K and the exposure unit 3K constitute a latent image forming unit.

  The developing units 4Y, 4M, 4C, and 4K contain a two-component developer including yellow (Y), magenta (M), cyan (C), and black (K) toner and a carrier.

  The intermediate transfer body 6 is wound around a plurality of rollers and is rotatably supported. The fixing device 9 includes a fixing roller 91 and a pressure roller 92, and fixes the toner image on the paper P by heating and pressing at a nip portion formed between the fixing roller 91 and the pressure roller 92.

  The feed roller 27 feeds the paper P on which the toner image is fixed toward the paper path switching device 30. The paper path switching device 30 includes a switching gate 31. The switching gate 31 is an example of a switching member, and is arranged so that the direction can be switched freely at a branch point of a normal discharge path 28 for normal discharge and a reverse path 29 for duplex printing or reverse discharge. The normal paper discharge path 28 is an example of a first transport path, and the reverse path 29 is an example of a second transport path. The switching gate 31 rotates in the same direction as the transport direction of the paper P, and the paper P comes into contact with it, so that the traveling direction of the paper P is changed to the normal paper discharge path 28 or the reverse path 29.

  Subsequently, an operation example of the image forming apparatus 100 will be described. The toner images of the respective colors formed by the image forming units 10Y, 10M, 10C, and 10K are sequentially transferred onto the rotating intermediate transfer member 6 by the primary transfer units 7Y, 7M, 7C, and 7K, and then onto the intermediate transfer member 6. A color toner image is formed by superimposing the toner images of the respective colors.

  The sheets P stored in the sheet feeding tray 21 are separated one by one by the sheet feeding roller 22 of the sheet feeding unit 20, and are fed through the sheet feeding roller 23 to the resist roller 24 in a stopped state. The registration roller 24 is temporarily stopped, and the registration roller 24 starts rotating at the timing when the position of the leading edge of the paper P and the toner image on the intermediate transfer body 6 coincide. As a result, the paper P is fed to the secondary transfer portion 7A, and the color toner image is transferred onto the paper P (secondary transfer). The paper P on which the color toner image has been transferred is heated and pressed by the fixing device 9, and the color toner image is fixed on the paper P. Thereafter, the feed roller 27 feeds the paper P toward the paper path switching device 30. The switching gate 31 of the paper path switching device 30 changes the traveling direction of the paper P to the normal paper discharge path 28 or the reverse path 29. The paper P sent to the normal paper discharge path 28 is nipped by the paper discharge roller 25 and placed on the paper discharge tray 26 outside the apparatus. Further, the paper P sent to the reverse path 29 is conveyed to the reverse paper discharge path 34 or the double-side path 35.

  On the other hand, after the color toner image is transferred to the paper P by the secondary transfer unit 7A, the residual toner is removed by the intermediate transfer body cleaning unit 8A from the intermediate transfer body 6 which has separated the curvature of the paper P.

  The image forming apparatus 100 that forms a color image has been described above, but may be an image forming apparatus that forms a monochrome image.

  FIG. 2A is a perspective view illustrating a configuration example of the switching gate 31 of the paper path switching device 30 as the first embodiment. 2B is a cross-sectional view taken along arrow XX in FIG. 2A. The switching gate 31 shown in FIG. 2A includes a belt 36, a solenoid 38, and a motor 39. The belt 36 is formed from a rubber material or the like. Three belt pulleys 40 to 42 are arranged inside the belt 36. These belt pulleys 40 to 42 are an example of a rotation support member, and are rotatably attached to the triangular plates 43 and 44. The belt pulleys 40 to 42 form the belt 36 into a triangular shape having switching surfaces R1 and R2 and rotatably support the belt 36.

  The motor 39 and the drive pulley 37 are an example of a rotation drive unit. A driving pulley 37 is coupled to the rotation shaft 39 b of the motor 39. The drive pulley 37 is disposed outside the belt 36 and is rotatably attached to a substantially intermediate position between the belt pulley 40 and the belt pulley 41 of the triangular plates 43 and 44. As shown in FIG. 2B, the driving pulley 37 presses the outer peripheral surface of the belt 36 and rotates the belt 36. Further, the drive pulley 37 functions as a rotation axis of the triangular plates 43 and 44.

  A solenoid 38, which is an example of a switching drive unit, is a push-type solenoid. The solenoid 38 is attached in the vicinity of the belt pulley 42 of the triangular plate 43. The solenoid 38 switches the direction of the switching gate 31 with the drive pulley 37 as a rotation axis by extending the movable iron core 38b by energizing the coil and moving straight.

  Next, a configuration example of the control system of the paper path switching device 30 will be described. FIG. 3 is a block diagram illustrating a configuration example of a control system of the paper path switching device 30. The control unit 50 of the paper path switching device 30 shown in FIG. 3 includes a ROM (Read Only Memory), a RAM (Random Access Memory), a HDD (Hard Disk Drive), and a CPU (Central Processing Unit). ) And an interface.

  The control unit 50 is connected to an operation unit 33, a solenoid driving driver 38a, a motor driving driver 39a, and a sensor 32. The operation unit 33 includes a duplex printing selection button, a reverse discharge selection button, and the like. The operation unit 33 selects each selection button by the user and outputs an operation signal S33 to the control unit 50. For example, when the duplex printing selection button or the reverse discharge selection button is pressed, the operation unit 33 outputs an operation signal S33 indicating that the paper is conveyed to the reverse path 29 to the control unit 50. Further, when the selection button is not pressed, the operation unit 33 outputs an operation signal S33 indicating that the paper is conveyed to the normal paper discharge path 28 to the control unit 50. The controller 50 controls the solenoid driving driver 38a based on the operation signal S33.

  The solenoid driving driver 38a receives the driving data D38a from the control unit 50, decodes the driving data D38a, and generates the control signal S38a. A solenoid 38 is connected to the driver 38a. The driver 38a drives the solenoid 38 to expand and contract based on the control signal S38a. When the solenoid 38 extends, the switching gate 31 shown in FIG. 2A rotates in the direction of the arrow Q1 with the driving pulley 37 as a rotation axis. When the solenoid 38 is contracted, the switching gate 31 shown in FIG. 2A rotates in the direction of the arrow Q2 with the driving pulley 37 as a rotation axis.

  The sensor 32, which is an example of a detection unit, is a reflection type sensor, detects the passage of the leading edge of the paper sent from the fixing device 9, and outputs a paper detection signal S 32 to the control unit 50. The paper detection signal S32 is a signal indicating the timing at which the rotation of the belt 36 of the switching gate 31 is started.

  The motor drive driver 39a receives drive data D39a from the control unit 50, decodes the drive data D39a, and generates a control signal S39a. A motor 39 is connected to the driver 39a. The driver 39a drives the motor 39 based on the control signal S39a. When the motor 39 rotates, the driving pulley 37 of the switching gate 31 shown in FIG. 2A rotates and the belt 36 rotates.

  Next, an operation example of the switching gate 31 of the paper path switching device 30 will be described. 4A and 4B are schematic diagrams illustrating examples of path switching of the switching gate 31. FIG. In order to facilitate understanding of the description, the configuration of the switching gate 31 is schematically described. The switching gate 31 shown in FIG. 4A is rotated downward with the drive pulley 37 as a rotation axis by the shrinkage of the solenoid 38. As a result, the transport path of the paper P is switched to the normal paper discharge path 28.

  The sensor 32 is disposed upstream of the branch point between the normal paper discharge path 28 and the reverse path 29. The sensor 32 detects passage of the leading end of the paper P and outputs a paper detection signal S32 to the control unit 50. The control unit 50 rotates the motor 39 in the transport direction of the paper P based on the paper detection signal S32. As a result, the drive pulley 37 of the switching gate 31 rotates and the belt 36 rotates. With the belt 36 rotated, the paper P is fed by the feed roller 27 as shown in FIG. 4A. The paper P sent out by the feed roller 27 travels in the direction of the arrow Q3 and is conveyed to the normal paper discharge path 28.

  The switching gate 31 shown in FIG. 4B is rotated upward by using the drive pulley 37 as a rotation axis by the extension of the solenoid 38. As a result, the transport path of the paper P is switched to the reverse path 29.

  The sensor 32 detects the passage of the leading edge of the paper P and outputs a paper detection signal S32 to the control unit 50. The control unit 50 rotates the motor 39 in the transport direction of the paper P based on the paper detection signal S32. As a result, the drive pulley 37 of the switching gate 31 rotates and the belt 36 rotates. With the belt 36 rotated, the paper P is fed by the feed roller 27 as shown in FIG. 4B. The leading edge of the paper P sent out by the feed roller 27 comes into contact with the belt 36 of the switching gate 31, and the paper P advances in the direction of the arrow Q 4 and is conveyed to the reverse path 29.

  Thus, when the transport direction of the paper P is switched, the leading end of the paper P abuts on the rotated belt 36, so that the collision between the paper P and the switching gate 31 can be buffered. As a result, the occurrence of collision noise between the paper P and the switching gate 31 and the damage to the paper P can be reduced.

  FIG. 5 is an explanatory diagram showing the drive timing of the belt drive motor 39. The sensor 32 shown in FIG. 5 outputs a high level voltage signal when, for example, a reflecting object (paper) is detected, and outputs a low level voltage signal when no reflecting object is detected. The controller 50 detects that the low level voltage signal output from the sensor 32 has risen to a high level voltage signal and determines that the sensor 32 is turned on.

  When determining that the sensor 32 is turned on, the control unit 50 outputs the drive data D39a shown in FIG. 3 to the driver 39a for driving the motor. The driver 39a drives the motor 39 based on a control signal S39a obtained by decoding the drive data D39a. When the motor 39 rotates, the driving pulley 37 of the switching gate 31 shown in FIGS. 4A and 4B rotates and the belt 36 rotates.

  6A and 6B are schematic diagrams illustrating a control example of the drive pulley 37 of the switching gate 31. FIG. The switching gate 31 shown in FIG. 6A rotates downward with the drive pulley 37 as a rotational axis. At this time, the drive pulley 37 of the switching gate 31 rotates in the direction of the arrow Q5 and the belt 36 also rotates in the direction of the arrow Q5. As a result, the traveling direction of the switching surface R1 of the belt 36 in contact with the paper P becomes equal to the direction of the arrow Q3 that conveys the paper P to the normal paper discharge path 28. Therefore, the belt 36 of the switching gate 31 can send out the paper P in the direction of the arrow Q3 with the paper P placed on the switching surface R1.

  The switching gate 31 shown in FIG. 6B rotates upward with the drive pulley 37 as a rotation axis. At this time, the drive pulley 37 of the switching gate 31 rotates in the direction of the arrow Q6 and the belt 36 also rotates in the direction of the arrow Q6. As a result, the traveling direction of the switching surface R2 of the belt 36 in contact with the paper P becomes equal to the direction of the arrow Q4 that conveys the paper P to the reverse path 29. Therefore, the belt 36 of the switching gate 31 can switch the traveling direction of the paper P, which contacts the paper P to the switching surface R2, in the direction of the arrow Q4.

  Next, an operation example of the control unit 50 of the paper path switching device 30 will be described. FIG. 7 is a flowchart illustrating an operation example of the control unit 50. In this example, a transfer path switching control program is stored in the HDD (not shown) of the control unit 50. The control unit 50 develops this control program in a RAM (not shown).

  In step ST <b> 1 shown in FIG. 7, the control unit 50 determines whether or not the operation signal S <b> 33 input from the operation unit 33 indicates that the paper is conveyed to the normal paper discharge path 28. When it is determined that the operation signal S33 indicates that the sheet is conveyed to the normal sheet discharge path 28, the process proceeds to step ST2.

  In step ST2, the control unit 50 controls the solenoid 38 to contract. In this example, the solenoid 38 is a push-type solenoid, and when the coil is not energized, the movable iron core 38b is kept in a contracted state by a return compression spring. Subsequently, the process proceeds to step ST3.

  In step ST <b> 3, the control unit 50 determines whether or not the sheet detection signal S <b> 32 is input from the sensor 32. If it is determined that the paper detection signal S32 is input, the process proceeds to step ST4.

  In step ST4, the control unit 50 rotates the motor 39 in the normal direction to rotate the drive pulley 37 of the switching gate 31 in the direction of the arrow Q5 shown in FIG. 6A. As a result, the belt 36 rotates in the direction of the arrow Q5, and the paper P can be conveyed to the normal paper discharge path 28. Subsequently, the process proceeds to step ST5.

  In step ST <b> 5, the control unit 50 determines whether or not the transport sheet is finished. If it is determined that the transport sheet is not finished, the process returns to step ST1.

  In step ST1, when the control unit 50 determines that the operation signal S33 input from the operation unit 33 indicates that the sheet is conveyed to the reverse path 29, the control unit 50 proceeds to step ST6.

  In step ST6, the control unit 50 controls the solenoid 38 to extend. For example, the control unit 50 energizes the coil of the solenoid 38 to extend the movable iron core 38b. As a result, as shown in FIG. 4B, the switching gate 31 rotates upward with the drive pulley 37 as a rotation axis, and switches the conveyance path of the paper P to the reversing path 29. Subsequently, the process proceeds to step ST3.

  If the control unit 50 determines in step ST3 that the sheet detection signal S32 is input from the sensor 32, the control unit 50 proceeds to step ST4. In step ST4, the control unit 50 reversely rotates the motor 39 to rotate the driving pulley 37 of the switching gate 31 in the direction of the arrow Q6 shown in FIG. 6B. As a result, the belt 36 rotates in the direction of the arrow Q6, and the paper P can be conveyed to the reverse path 29. Subsequently, the process proceeds to step ST5.

  In step ST5, when the control unit 50 determines that the transport sheet is finished, the control unit 50 proceeds to step ST7. In step ST7, the control unit 50 stops the motor 39 and stops energization of the solenoid 38 to contract the solenoid 38 and finish the paper transport process.

  As described above, according to the paper path switching device 30 according to the first embodiment of the present invention, the switching gate 31 arranged at the branch point of the normal paper discharge path 28 and the reversing path 29 so that the direction can be switched is And the sheet abuts to change the advancing direction of the sheet.

  With this configuration, when the sheet transport direction is switched, the collision between the end portion of the sheet and the switching gate 31 can be buffered. As a result, it is possible to reduce the occurrence of collision noise between the paper and the switching gate 31 and damage to the paper.

  Next, a configuration example for switching the direction of the switching gate 31 without using the solenoid 38 will be described. FIG. 8 is a perspective view showing a configuration example of the switching gate 31A of the paper path switching device 30A as the second embodiment. The same components as those of the switching gate 31 shown in FIG. 2A are denoted by the same reference numerals, and detailed description thereof is omitted.

  The switching gate 31A shown in FIG. 8 does not include the solenoid 38 shown in FIG. 2A. The switching gate 31 </ b> A includes a driving pulley 37 that contacts the outer peripheral surface of the belt 36. The switching gate 31A utilizes the frictional force generated when the drive pulley 37 rotates the belt 36, and rotates in the direction of the arrow Q1 with the drive pulley 37 as a rotation axis to switch the direction of the belt 36. At this time, the upper stop position of the switching gate 31A is determined by contacting the triangular plates 43 and 44 with an upper defining member (not shown) provided in the apparatus main body.

  Further, the switching gate 31A uses the frictional force generated when the driving pulley 37 rotates the belt 36, and rotates in the direction of the arrow Q2 with the driving pulley 37 as a rotation axis to switch the direction of the belt 36. At this time, the lower stop position of the switching gate 31A is determined by the triangular plates 43 and 44 coming into contact with a lower regulating member (not shown) provided in the apparatus main body.

  Next, an operation example of the control unit 50A of the paper path switching device 30A will be described. Although the configuration of the control unit 50A is not shown, the solenoid 38 and its driver 38a are not provided from the block diagram shown in FIG.

  FIG. 9 is a flowchart illustrating an operation example of the control unit 50A. In step ST11 shown in FIG. 9, the control unit 50A determines whether or not the paper detection signal S32 is input from the sensor 32. If it is determined that the paper detection signal S32 is input, the process proceeds to step ST12.

  In step ST <b> 12, the control unit 50 </ b> A determines whether or not the operation signal S <b> 33 input from the operation unit 33 indicates that the sheet is conveyed to the normal sheet discharge path 28. When it is determined that the operation signal S33 indicates that the sheet is conveyed to the normal sheet discharge path 28, the process proceeds to step ST13.

  In step ST13, the control unit 50A rotates the motor 39 in the normal direction to rotate the drive pulley 37 of the switching gate 31 in the direction of the arrow Q5 illustrated in FIG. 6A. At this time, the switching gate 31 rotates in the downward direction using the driving pulley 37 as a rotation axis by using a frictional force generated when the driving pulley 37 rotates the belt 36. As a result, the paper P can be conveyed to the normal paper discharge path 28. Subsequently, the process proceeds to step ST14.

  In step ST14, the control unit 50A determines whether or not the conveyance sheet is finished. If it is determined that the transport sheet has not been completed, the process returns to step ST11. In step ST11, when the control unit 50A determines that the paper detection signal S32 is input from the sensor 32, the process proceeds to step ST12.

  When the control unit 50A determines in step ST12 that the operation signal S33 input from the operation unit 33 indicates that the sheet is conveyed to the reversing path 29, the control unit 50A proceeds to step ST16.

  In step ST16, the control unit 50A rotates the motor 39 in the reverse direction to rotate the drive pulley 37 of the switching gate 31 in the direction of the arrow Q6 shown in FIG. 6B. At this time, the switching gate 31 rotates upward using the driving pulley 37 as a rotation axis by utilizing the frictional force generated when the driving pulley 37 rotates the belt 36. As a result, the paper P can be conveyed to the reverse path 29. Subsequently, the process proceeds to step ST14.

  In step ST14, the control unit 50A determines whether or not the conveyance sheet is finished. If it is determined that the transport sheet has been completed, the process proceeds to step ST15. In step ST15, the control unit 50A stops the motor 39 and ends the paper transport process.

  As described above, according to the sheet path switching device 30A as the second embodiment of the present invention, the switching gate 31A that changes the traveling direction of the sheet generates the frictional force when the drive pulley 37 rotates the belt 36. By utilizing this, the drive pulley 37 is rotated about the rotation axis. Since the solenoid 38 is not used in this way, the switching gate 31A can reduce the number of parts compared to the switching gate 31.

  Note that the switching member that switches the paper conveyance path is not limited to the configuration of the switching gate 31 and the switching gate 31 </ b> A in which the belt 36 formed in a triangular shape is rotated by the driving pulley 37. For example, in the switching gate 31B shown in FIG. 10A, two belt pulleys 40 and 42 and a drive pulley 37a are arranged inside the belt 36a. The belt pulleys 40 and 42 and the drive pulley 37a form the belt 36a in a triangular shape and rotatably support the belt 36a. The drive pulley 37a contacts the inner peripheral surface of the belt 36a and rotates the belt 36a. Further, the drive pulley 37a functions as a rotation shaft of the triangular plates 43 and 44. The switching gate 31B rotates about the drive pulley 37a as a rotation axis as indicated by a two-dot chain line. The switching gate 31 shown in FIG. 2B may be configured as a switching gate 31B.

  Further, in the switching gate 31C shown in FIG. 10B, a belt pulley 42 and a drive pulley 37b are arranged inside the belt 36b. The belt pulley 42 and the drive pulley 37b form the belt 36b in a straight line and rotatably support the belt 36b. The driving pulley 37b contacts the inner peripheral surface of the belt 36b and rotates the belt 36b. Further, the drive pulley 37b functions as a rotating shaft of the linear plate 44a. The switching gate 31C rotates about the drive pulley 37b as a rotation axis as indicated by a two-dot chain line. The switching gate 31 shown in FIG. 2B may be configured as a switching gate 31C.

  The present invention is suitable for application to an image forming apparatus that switches a paper transport path to a first transport path that performs normal discharge of printing paper or a second transport path that performs duplex printing or reverse paper discharge.

1 is a schematic diagram illustrating a configuration example of an image forming apparatus 100 according to the present invention. FIG. 3 is a perspective view illustrating a configuration example of a switching gate 31 of the paper path switching device 30 as the first embodiment. 3 is a block diagram illustrating a configuration example of a control system of a paper path switching device 30. FIG. A and B are schematic diagrams illustrating an example of path switching of the switching gate 31. It is explanatory drawing which shows the drive timing of the motor 39 for a belt drive. A and B are schematic diagrams illustrating an example of control of the drive pulley 37 of the switching gate 31. 3 is a flowchart showing an operation example of a control unit 50. It is a perspective view which shows the structural example of switching gate 31A of the paper path | route switching apparatus 30A as 2nd Embodiment. It is a flowchart which shows the operation example of 50 A of control parts. A and B are cross-sectional views illustrating configuration examples of the switching gates 31B and 31C. It is the schematic which shows the example of a path | route switch of the switching guide 60 which concerns on a prior art example.

Explanation of symbols

  28... Normal discharge path (first transport path), 29... Reverse path (second transport path), 30... Paper path switching device, 31, 31 </ b> A to 31 </ b> C. ), 32... Sensor (detection unit), 33 ..operation unit, 36, 36 a, 36 b... Belt, 38... Solenoid (switching drive unit), 39. 40-42 ... belt pulley (rotation support member), 50, 50A ... control unit, 100 ... image forming apparatus, R1, R2 ... switching surface, GH ... image forming unit

Claims (5)

A paper path switching device that switches a paper transport path to a first transport path or a second transport path,
A switching member that is disposed at a branching point of the first transport path and the second transport path so as to be capable of switching the direction, rotates in the same direction as the transport direction of the paper, and contacts the paper to change the traveling direction of the paper;
A switching drive unit that switches the direction of the switching member;
An operation unit for setting a paper transport path to the first transport path or the second transport path;
A sheet path switching apparatus comprising: a control unit that controls the switching drive unit based on path information set by the operation unit. The switching member is
A belt against which the paper abuts;
The paper path switching according to claim 1, further comprising: a rotation support member disposed inside the belt and forming the belt into a predetermined shape having a switching surface and rotatably supporting the belt. apparatus. A rotation drive unit for rotating the belt;
A detection unit that is disposed upstream of a branch point of the first conveyance path and the second conveyance path, detects a sheet, and outputs a detection signal to the control unit;
The controller is
The paper path switching device according to claim 2, wherein the rotation driving unit is controlled to rotate in a paper transport direction based on the detection signal. A paper path switching device that switches a paper transport path to a first transport path or a second transport path,
A belt is disposed at a branching point of the first transport path and the second transport path so as to be capable of switching the direction, and rotates in the same direction as the paper transport direction and changes the traveling direction of the paper by contacting the paper. A switching member;
A rotation drive unit that rotates the belt of the switching member and switches the direction of the belt;
An operation unit for setting a paper transport path to the first transport path or the second transport path;
A paper path switching apparatus comprising: a control unit that controls the rotation driving unit based on path information set by the operation unit. An image forming apparatus that switches a paper transport path on which an image is formed to a first transport path or a second transport path,
An image forming unit for forming an image on paper;
It is arranged at the branching point of the first transport path and the second transport path so that the direction can be switched, and rotates in the same direction as the transport direction of the sheet on which the image is formed by the image forming unit and the sheet comes into contact with the sheet. A switching member that changes the traveling direction of
A switching drive unit that switches the direction of the switching member;
An operation unit for setting a paper transport path to the first transport path or the second transport path;
An image forming apparatus comprising: a control unit that controls the switching drive unit based on path information set by the operation unit.

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