JP4872471B2 - Paper discharge device and image forming apparatus - Google Patents

Description

  The present invention relates to a paper discharge device and an image forming apparatus.

  In general, in an image forming apparatus such as a copying machine or a printer, when a sheet on which an image is formed is discharged to a discharge tray, the sheet is discharged with a waist. This waist is also called corrugation and has a wave shape formed on the paper, and the top of this wave shape extends in the paper conveyance direction (discharge direction) to form a line. As described above, the sheet can be discharged to the discharge tray in a state where the sheet curl has been removed by discharging the sheet with the waist.

  With regard to this type of image forming apparatus, for example, Patent Document 1 discloses a configuration in which a first roll and a second roll are relatively moved in the axial direction to switch between a corrugation application state and a corrugation non-application state. In addition, a configuration is described in which a corrugation imparting member is moved back and forth with respect to a paper conveyance path to switch between a corrugation imparting state and a corrugation non-given state.

JP-A-9-227007

  SUMMARY OF THE INVENTION An object of the present invention is to provide a paper discharge device and an image forming apparatus that can change the position and strength of the sheet to be discharged.

Images forming apparatus according to claim 1 includes an image forming means for forming an image on a sheet, a discharge roller for discharging the sheet on which an image has been formed by said image forming means, the sheets discharged by said discharge roller A plurality of seating members provided at a predetermined interval in a direction orthogonal to the paper transport direction in order to attach the waist, and the plurality of seating members in a direction intersecting the paper surface of the paper discharged by the discharge roll In a double-sided image forming process in which images are formed on both sides of a plurality of driving means and paper that are individually moved , when a part of the paper on which the image is formed on the first surface is discharged out of the apparatus by the discharge roll, When the plurality of seating members are selectively moved from the retracted position to the seated position under the first condition, and the sheet on which the image is formed on the second surface is discharged out of the apparatus by the discharge roll, Multiple seating members Is characterized in that it comprises a control means for controlling said plurality of drive means so as to selectively move the waist with a position from the retracted position in the serial first condition is different from the second condition.

The image forming apparatus according to claim 2 is the image forming apparatus according to claim 1 , wherein the control unit discharges a part of the sheet on which the image is formed on the first surface in the double-sided image forming process. Control is performed so that all of the plurality of seating members are moved to the retracted position after being discharged out of the apparatus by the roll and before the sheet is drawn into the apparatus by reverse rotation of the discharge roll. Is.

  According to the paper discharge device of the first aspect, the position and strength at which the paper is discharged can be changed by individually moving the plurality of backrest members by the plurality of driving means. it can.

  According to the paper discharge device of the second aspect, it is possible to appropriately switch the movement positions of the plurality of seating members in accordance with the type of paper discharged by the discharge roll.

  According to the paper discharge device of the third aspect, it is possible to set the seating condition of the sheet by the plurality of seating members to an arbitrary condition according to the desire of the operator.

  According to the image forming apparatus of claim 4, the plurality of back-resting members are individually moved by the plurality of driving units, thereby changing the position where the back is seated on the paper on which the image is formed, You can change the strength to do.

  According to the image forming apparatus of claim 5, in the double-sided image forming process, when a part of the paper on which the image is formed on the first surface is discharged out of the apparatus, the image is formed on the second surface. When ejecting paper out of the machine, by changing the conditions for selectively moving multiple seating members from the retracted position to the seated position, seat on the paper with images formed on both sides. It can be discharged in a wet state.

  According to the image forming apparatus of the sixth aspect, it is possible to reduce noise generated when a part of the sheet is discharged outside the apparatus and then the sheet is pulled into the apparatus.

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

  FIG. 1 is a schematic view showing a configuration of an electrophotographic image forming apparatus according to an embodiment of the present invention. In the figure, the image forming apparatus main body 1 incorporates three sheet storage portions 2, 3, and 4 in an upper, middle, and lower multi-stage structure. Each of the paper storage units 2, 3, and 4 stores a predetermined number of papers in a stacked state. Among these, the paper storage unit 2 is arranged in the upper stage, the paper storage part 3 is arranged in the middle stage, and the paper storage part 4 is arranged in the lower stage.

  Further, in the vicinity of the sheet storage unit 2, a calling roll 5 and a delivery roll 6 are arranged as sheet feeding rolls. The calling roll 5 is for calling the sheets stored in the sheet storage unit 2 one by one in order from the top. The delivery roll 6 is for delivering the sheet called by the calling roll 5 to the downstream side in the sheet conveyance direction. Similarly, a calling roll 7 and a sending roll 8 are arranged in the vicinity of the sheet storage unit 3, and a calling roll 9 and a sending roll 10 are arranged in the vicinity of the sheet storage unit 4.

  Further, on the paper transport path that is the destination of the paper fed from each of the paper storage units 2, 3, 4, a transport roll 11, a transport roll 12, a registration roll 13, a reverse roll 14, and a transport roll 15, a transport roll 16, and a transport roll 17 are arranged. The transport roll 11 receives and transports the paper sent out by the feed roll 10. The transport roll 12 receives and transports the paper fed by the feed roll 8 and the paper transported by the transport roll 11.

  The registration roll 13 feeds the paper fed by the feed roll 6 and the paper fed by the transport roll 12 or the transport roll 17 to the image transfer position at a predetermined timing. The image transfer position refers to a position where an image (toner image) is transferred to a sheet being conveyed.

  An image transfer unit 18 and an image fixing unit 19 are sequentially arranged from the upstream side to the downstream side in the paper conveyance direction on the paper conveyance path from the registration roll 13 to the reverse roll 14. The image transfer unit 18 is a part that transfers the toner image onto the sheet fed by the registration roll 13. A photosensitive drum 20 and a transfer roll 21 are disposed in the image transfer unit 18. The photoconductor drum 20 and the transfer roll 21 are disposed to face each other via a paper conveyance path, and a toner image is transferred from the photoconductor drum 20 to the paper when passing through the facing portion. Therefore, the facing portion between the photosensitive drum 20 and the transfer roll 21 is the image transfer position.

  The transfer roll 21 is pressed against the photoconductor drum 20 with a predetermined pressure, and applies a charge having a polarity opposite to that of the toner to the paper while sandwiching and rotating the paper with the photoconductor drum 20. The toner image is transferred from 20 to a sheet. In addition to the transfer roll 21, a charging device, an image writing device, a developing device, a drum cleaner, and the like (not shown) are disposed around the photosensitive drum 20. The charging device charges the surface of the photosensitive drum 20 to a predetermined potential. The image writing apparatus writes an electrostatic latent image on the surface of the photosensitive drum 20 by exposing and scanning the surface of the photosensitive drum 20 charged to a predetermined potential with a laser beam. The developing device develops the positive transmission latent image written on the photosensitive drum 20 into a toner image using, for example, a two-component developer composed of toner and carrier. The drum cleaner removes unnecessary toner remaining on the surface of the photosensitive drum 20 without being transferred onto the paper.

  The image fixing unit 19 fixes the toner image transferred to the paper by the image transfer unit 18. The image fixing unit 19 is provided with a heating roll 22 and a pressure roll 23. The heating roll 22 is heated to a predetermined temperature (fixing temperature) by a heater or the like when fixing an image on a sheet. The pressure roll 23 is disposed so as to contact the heating roll 22 with a predetermined pressure.

  The reversing roll 14 is composed of a pair of rolls that come into contact with each other with a predetermined pressure. The reversing roll 14 is provided so as to be capable of rotating in both directions (forward / reverse rotation). Therefore, when the reversing roll 14 is rotated forward and reversely, the traveling direction of the paper is reversed. In the present embodiment, when the reversing roll 14 is rotated forward, the sheet advances by receiving an upward conveying force from the reversing roll 14, and when the reversing roll 14 is rotated reversely, the sheet receives a conveying force downward from the reversing roll 14. It has come to receive.

  The transport rollers 15, 16, and 17 are provided in the reverse transport unit 24. The reverse conveyance unit 24 is a part that receives and conveys the paper on which the image is formed on the first surface from the reverse roll 14 in order to form images on both sides of the paper. A paper transport path is formed in the reverse transport section 24, and the transport rolls 15, 16, and 17 are arranged at predetermined intervals on the paper transport path. In the reverse conveyance unit 24, the conveyance roll 15 is disposed on the most upstream side in the sheet conveyance direction, and the conveyance roll 17 is disposed on the most downstream side in the sheet conveyance direction. The paper conveyance path of the reverse conveyance unit 24 is formed so as to relay the paper conveyance path branched from the front (upstream side) of the reverse roll 14 and the paper conveyance path joining the front (upstream side) of the registration roll 13. ing.

  The image forming apparatus main body 1 is provided with three paper discharge units 25, 26, and 27. A discharge roll 28 is provided in the paper discharge unit 25. The paper discharge unit 26 is provided with a discharge roll 29, and the paper discharge unit 27 is provided with a discharge roll 30.

  The discharge roll 28 discharges the sheet fed from the image fixing unit 19 to the sheet discharge unit 25 along the sheet conveyance path. The sheets discharged by the discharge roll 28 are stacked and stored on the first discharge tray 31.

  The discharge roll 29 discharges the paper fed from the image fixing unit 19 to the paper carry-out unit 26 via the reverse roll 14 along the paper conveyance path. The sheets discharged by the discharge roll 29 are stacked and stored on a second discharge tray (not shown). Further, the discharge roll 29 is provided so as to be capable of rotating in both directions (forward / reverse rotation) in the same manner as the reverse roll 14. Therefore, when the transport roll 29 is rotated in the forward direction and in the reverse direction, the paper traveling direction is reversed. In the present embodiment, when the discharge roll 29 is rotated forward, the paper advances by receiving a rightward conveyance force from the discharge roll 29, and when the discharge roll 29 is rotated in the reverse direction, the paper has a leftward conveyance force from the discharge roll 29. It has come to receive.

  The discharge roll 30 discharges the paper sent from the image fixing unit 19 to the paper carry-out unit 27 via the reverse roll 14 along the paper conveyance path. The sheets discharged by the discharge roll 30 are stacked and stored on a third discharge tray (not shown).

  Further, a paper thickness detection sensor 32 is provided between the calling roll 5 and the delivery roll 6 in the paper transport direction. Further, a paper thickness detection sensor 33 is provided between the calling roll 7 and the sending roll 8, and a paper thickness detection sensor 34 is provided between the calling roll 9 and the sending roll 10. The paper thickness detection sensor 32 detects the thickness of the paper called by the calling roll 5. The paper thickness detection sensor 33 detects the thickness of the paper called by the calling roll 7, and the paper thickness detection sensor 34 detects the thickness of the paper called by the calling roll 9. .

  On the other hand, a paper width detection sensor 35 is provided between the registration roll 13 and the image transfer unit 18. The paper width detection sensor 35 detects the width of the paper conveyed on the paper conveyance path between the registration roll 13 and the image transfer unit 18. The paper width refers to a paper size in a direction (main image scanning direction) orthogonal to the paper transport direction.

  The image forming apparatus main body 1 is provided with an operation display unit 36. The operation display unit 36 is used by an operator who operates the image forming apparatus to input various information or display various information to the operator. The operation display unit 36 includes, for example, an input operation unit having various buttons, switches, keys, and the like, and a display unit including a liquid crystal display.

  Here, a basic operation procedure of the image forming apparatus configured as described above will be described. First, for example, when an image is formed on a sheet stored in the upper sheet storage unit 2 out of the three sheet storage units 2, 3 and 4, by rotation of the corresponding call roll 5 and delivery roll 6 Paper is supplied from the paper storage unit 2. When an image is formed on the paper stored in the middle paper storage unit 3, the paper is supplied from the paper storage unit 3 by the rotation of the corresponding call roll 7 and delivery roll 8, and the lower paper storage unit When an image is formed on the paper stored in the paper 4, the paper is supplied from the paper storage unit 4 by the rotation of the corresponding call roll 9 and delivery roll 10.

  Next, the paper supplied from one of the paper storage units is transported according to the rotation of the transport rolls 11 and 12. Next, the inclination of the sheet is corrected by abutting the leading end of the sheet against the resist roll 13 in the rotation stopped state. Next, the sheet is fed into the image transfer unit 18 by starting the rotation of the registration roll 13 at a predetermined timing.

  Subsequently, the sheet reaching the image transfer unit 28 is sandwiched between the photosensitive drum 20 and the transfer roll 21 and conveyed, whereby the toner image is transferred from the photosensitive drum 20 to the sheet. Next, the sheet is fed into the image fixing unit 19 where the sheet is sandwiched between the heating roll 22 and the pressure roll 23 and conveyed to fix the toner image on the sheet. As a result, an image is formed on the first surface of the sheet.

  When the sheet having the image formed on the first surface is discharged to the first discharge tray 31, the sheet moving direction (path) sent from the image fixing unit 19 is switched by a switching member (not shown). Is guided to the discharge roll 28 of the paper discharge unit 25. Then, the paper is discharged onto the first discharge tray 31 according to the rotation of the discharge roll 28.

  In addition, when the sheet on which the image is formed on the first surface is discharged to a second discharge tray (not shown), the sheet is fed by switching the advancing direction of the sheet sent from the image fixing unit 19 with a switching member (not shown). The reversing roll 14 is guided to the discharge roll 29 of the paper discharge unit 26. Then, according to the rotation of the discharge roll 29, the sheet is discharged onto a second discharge tray (not shown).

  Further, when the sheet having the image formed on the first surface is discharged to a third discharge tray (not shown), the sheet is fed by switching the advancing direction of the sheet sent from the image fixing unit 19 with a switching member (not shown). The reversing roll 14 is guided to the discharge roll 30 of the paper discharge unit 27. Then, the paper is discharged onto a third discharge tray (not shown) as the discharge roll 30 rotates.

  On the other hand, when images are formed on both sides of a sheet, the sheet is guided from the reversing roll 14 to the discharge roll 29 by switching the traveling direction of the sheet sent from the image fixing unit 19 with a switching member (not shown). Then, the rotation of the reverse roll 14 and the discharge roll 29 is stopped in a state where a part of the paper is discharged to the outside of the apparatus (on the second discharge tray) according to the normal rotation of the reverse roll 14 and the discharge roll 29.

  Next, by rotating the reverse roll 14 and the discharge roll 29 in reverse, the paper is drawn into the machine, and the paper is moved from the reverse roll 14 to the discharge roll 15 by switching the traveling direction of the paper with a switching member (not shown). Send it in. Such a paper inversion method is also called a switchback method. Thereafter, the paper is transported according to the rotation of the transport rollers 15, 16, and 17, so that the leading edge of the paper again strikes the resist roll 13 in the rotation stopped state.

  Next, a toner image is formed (transferred and fixed) on the second surface of the paper in the same procedure as described above. As a result, an image is formed on both sides of the paper. Thereafter, the paper is discharged to one of the discharge trays in the same procedure as described above.

  FIG. 2 is a view of the paper discharge unit 26 as viewed from the direction of arrow A in FIG. 1 as a configuration example of the paper discharge unit. The paper discharge unit 26 is provided with a plurality (four in the illustrated example) of discharge rolls 29 at a predetermined interval in a direction (left and right direction in the figure) orthogonal to the paper transport direction. The interval and the number of the discharge rolls 29 can be appropriately changed according to the maximum width and the minimum width of the paper handled by the image forming apparatus. Each discharge roll 29 is configured by a drive roll 29A and a driven roll 29B that are in contact with each other with a predetermined pressure.

  The drive roll 29A rotates about a rotation drive shaft 37 disposed in a direction orthogonal to the paper transport direction, and the driven roll 29B rotates about a virtual axis 38 parallel to the rotation drive shaft 37. is there. Further, the drive roll 29A and the driven roll 29B are arranged in a state of facing each other in the vertical direction with the drive roll 29A on the upper side and the driven roll 29B on the lower side.

  The rotational drive shaft 37 is configured using, for example, a metal shaft. The rotation drive shaft 37 rotates in both directions using a motor (not shown) as a drive source, and a plurality of drive rolls 29A are attached to the rotation drive shaft 37. Therefore, when the rotary drive shaft 37 is rotated, the plurality of drive rolls 29A are simultaneously rotated integrally therewith.

  On the other hand, each driven roll 29B is supported by a roll support member (not shown) (for example, a bracket and a bearing member) so as to be individually rotatable around the virtual shaft 38. Further, each driven roll 29B is individually pressed against the drive roll 29A by a roll pressing member (for example, a spring member) (not shown).

  Further, in addition to the plurality of discharge rolls 29 described above, the sheet discharge unit 26 is provided with a plurality of (four in the illustrated example) seating members 39A, 39B, 39C, 39D, and 39E. The plurality of seating members 39A, 39B, 39C, 39D, and 39E are for seating on the paper ejected by the ejection roll 29, and in a direction perpendicular to the paper transport direction (rotation axis direction of the transport roll 29). They are provided at predetermined intervals. More specifically, each backing member 39A, 39B, 39C, 39D, 39E has a driven roll 29B interposed between two adjacent backing members in the rotational axis direction of the discharge roll 29. Is arranged.

  Further, in the image forming apparatus according to the embodiment of the present invention, a center reference method that conveys a sheet based on the center of the sheet width is adopted as a sheet conveyance method. When this center reference method is adopted, the center of the sheet width passes through a common reference position (hereinafter referred to as “center reference position”) even if the width of the sheet conveyed through the sheet conveyance path changes. Become. Therefore, in the rotation axis direction of the discharge roll 29 (direction orthogonal to the paper transport direction), the two inner discharge rolls 29 are arranged at the same distance from the center reference position, and the two outer discharge rolls 29 are also the center reference. It is arranged at a position equidistant from the position.

  Further, a seating portion 39C is disposed at the center reference position in the rotation axis direction of the discharge roll 29. Then, the seating members 39B and 39D are arranged at a position equidistant from the seating portion 39C with the center reference position as the center, and further, the seating members 39A and 39E are disposed at the outer side and at a position equidistant from the seating portion 39C. Is arranged.

  Further, in the rotational axis direction of the discharge roll 29, the discharge roll 29 disposed outside the seating portion 39D and the outer end portion of the seating portion 39D, with the center reference position as the center. The distance between the outer ends of the discharge roll 29 is the first distance L1 between the rolls, and the distance between the outer ends of the discharge rolls 29 disposed on both sides of the seating portion 39C is the second distance L2 between the rolls. To do. In this case, the magnitude relationship between the inter-roll distances L1 and L2 is L1> L2.

  Each of the seating members 39A, 39B, 39C, 39D, and 39E is formed in a roll shape, for example, and is centered on a virtual axis (an axis different from the virtual axis 38) parallel to the rotation drive shaft 37. It is supported rotatably. Each of the seating members 39A, 39B, 39C, 39D, and 39E is movably supported by an independent drive mechanism. In the embodiment of the present invention, a plurality of drive mechanisms are provided so as to correspond to the plurality of seating members 39A, 39B, 39C, 39D, 39E in a 1: 1 relationship. The plurality of drive mechanisms individually move the seating members 39A, 39B, 39C, 39D, and 39E in a direction (vertical direction in FIG. 2) intersecting the paper surface of the paper discharged by the discharge roll 29. is there.

  FIGS. 3A and 3B show an example of a drive mechanism for moving the seating member. FIG. 3A is a view seen from the side, and FIG. 3B is a view seen from the top. In the configuration of the driving mechanism 40 shown in the figure, a seating member 39 is rotatably attached to one end side of the swinging member 41. The swing member 41 is supported by the support member 42 so as to be swingable about the fulcrum Pc. Further, a fan-shaped power receiving portion 43 is formed on the other end side of the swing member 41. The arc portion of the power receiving portion 43 is an arc centered on the fulcrum Pc, and teeth 44 are formed on the arc portion. A gear 46 is attached to the rotating shaft of the motor 45. The gear 46 meshes with the above-described tooth 44.

  In the drive mechanism 40 having the above-described configuration, when the motor 45 serving as a drive source is driven, the gear 46 rotates. The gear 46 meshes with teeth 43 formed on the power receiving portion 43 of the swing member 41. For this reason, when the gear 46 rotates, the rotational driving force is transmitted to the power receiving portion 43. Therefore, the swinging member 41 swings around the fulcrum Pc according to the rotation direction of the gear 46. As a result, the position of the seating member 39 moves in the direction opposite to the power receiving portion 43 around the fulcrum Pc. That is, when the power receiving portion 43 moves downward, the seating member 39 moves upward, and when the power receiving portion 43 moves upward, the seating member 39 moves downward.

  FIG. 4 shows an arrangement state of two seating members 39B, 39C and two corresponding drive mechanisms 40B, 40C among the above four seating members 39A, 39B, 39C, 39D, 39E. .

  In the embodiment of the present invention, by controlling the driving (rotation direction, rotation amount, etc.) of the motor 45, the position of the seating member 39 is “retracted” in the direction intersecting the paper surface of the paper discharged by the discharge roll 29. ”,“ Weak ”,“ Medium ”and“ Strong ”. In the state where the waist member 39 is moved to the “retracted” position, as shown in FIG. 5A, the direction connecting the rotation center axes P1 and P2 of the drive roll 29A and the driven roll 29B (vertical direction in the figure). Thus, the seating member 39 is disposed in a state of being retracted (separated) by a distance La from the facing portion (contact portion) of the rolls 29A and 29B to the rotation center axis P2 side of the driven roll 29B. Thus, in the state in which the seating member 30 is disposed at the “retracted” position, the seating member 30 does not come into contact with the sheet of paper discharged by the discharge rolls 29 (29A, 29B). For this reason, the seating by the seating member 30 is not performed on the paper ejected by the ejection rolls 29 (29A, 29B).

  On the other hand, in the state where the seating member 39 is moved to the “weak” position, as shown in FIG. 5 (B), the roll in the direction connecting the rotation center axes P1 and P2 of the drive roll 29A and the driven roll 29B. The seating member 39 is disposed so as to protrude (advance) by a distance Lb to the rotation center axis P1 side of the drive roll 29A from the opposing portion (contact portion) of 29A and 29B. Thus, in the state where the seating member 30 is disposed at the “weak” position, the seating member 30 comes into contact with the paper surface of the paper discharged by the discharge rolls 29 (29A, 29B) by the protrusion of the distance Lb. . For this reason, the sheet discharged by the discharge roll 29 (29A, 29B) is seated by the seating member 30 with a strength corresponding to the protruding amount of the distance Lb.

  Further, in the state in which the seating member 39 is moved to the “middle” position, as shown in FIG. 5C, the rolls in the direction connecting the rotation center axes P1 and P2 of the drive roll 29A and the driven roll 29B. The seating member 39 is disposed so as to protrude (advance) by a distance Lc longer than the distance Lb on the side of the rotation center axis P1 of the drive roll 29A relative to the opposing part (contact part) of 29A and 29B. In this state where the seating member 30 is disposed at the “medium” position, the seating member 30 comes into contact with the paper surface of the paper discharged by the discharge rolls 29 (29A, 29B) by the protrusion of the distance Lc. . Therefore, the sheet discharged by the discharge roll 29 (29A, 29B) is seated by the seating member 30 with a strength corresponding to the protruding amount of the distance Lc.

  Further, in the state where the seating member 39 is moved to the “strong” position, as shown in FIG. 5 (D), the roll in the direction connecting the rotation center axes P1 and P2 of the drive roll 29A and the driven roll 29B. The seating member 39 is disposed so as to protrude (advance) by a distance Ld longer than the distance Lc on the rotation center axis P1 side of the drive roll 29A than the opposed portions (contact portions) of 29A and 29B. In this state where the seating member 30 is arranged at the “strong” position, the seating member 30 comes into contact with the paper surface of the paper discharged by the discharge rolls 29 (29A, 29B) by the protrusion of the distance Ld. . For this reason, the sheet that is discharged by the discharge roll 29 (29A, 29B) is seated by the seating member 30 with a strength corresponding to the protruding amount of the distance Ld.

  From the above, the “retreat” position is a retreat position for retreating from the seating member 39 from the surface of the sheet discharged by the discharge roll 29. Further, the positions of “weak”, “medium”, and “strong” are seating positions where the seating member 39 comes into contact with the paper surface of the sheet discharged by the discharge roll 29 and seats. Further, the strength of the seating by the seating member 30 is proportional to the magnitude relationship of the distances Lb, Lc and Ld described above. For this reason, the strength of the seating by the seating member 30 is increased when the seating member 30 is disposed at the “medium” position than when the seating member 30 is disposed at the “weak” position. Similarly, the strength of the seating by the seating member 30 is increased when the seating member 30 is disposed at the “strong” position than when the seating member 30 is disposed at the “medium” position.

  FIG. 6 is a block diagram showing an example of a control configuration for controlling the movement operation of the seating member as the configuration of the control system of the image forming apparatus according to the embodiment of the present invention. The control unit 47 comprehensively controls the operation of the image forming apparatus (including the image forming operation and the sheet conveying operation). Moreover, the control part 47 controls the drive of each motor 45A, 45B, 45C, 45D, 45E separately. The motor 45A is a drive source of a drive mechanism that moves the seating member 39A. The motor 45B serves as a drive source for a drive mechanism that moves the seating member 39B, and the motor 45C serves as a drive source for a drive mechanism that moves the seating member 39C. Further, the motor 45D serves as a drive source for a drive mechanism that moves the seating member 39D, and the motor 45E serves as a drive source for a drive mechanism that moves the seating member 39E. The control unit 47 is connected to the above-described paper thickness detection sensors 32, 33, 34, the paper width detection sensor 35, and the operation display unit 36.

  FIG. 7 is a flowchart showing an example of control processing performed by the control unit 47. In the following control processing, it is assumed that a sheet on which image formation on one side has been completed or a sheet on which image formation has been completed on both sides is discharged from the sheet discharge unit 26. Also, it is assumed that each of the seating members 39A, 39B, 39C, 39D, and 39E is waiting at the “retracted” position.

  First, when the operator performs an operation such as pressing a start button provided on the operation display unit 36 using the operation display unit 36 to instruct the start of image forming processing, the control unit 47 receives this instruction. (Step S1).

  Next, the thickness of the paper that is the object of image formation is detected (step S2). For example, when a sheet to be subjected to image formation is supplied from the upper sheet storage unit 2, the sheet thickness detection sensor 32 provided corresponding thereto detects the sheet thickness. Further, when a sheet to be imaged is supplied from the middle sheet storage unit 3, the sheet thickness detection sensor 33 provided corresponding to this detects the thickness of the sheet and sets the image forming target. When the sheet to be formed is supplied from the lower sheet storage unit 4, the sheet thickness detection sensor 34 provided corresponding thereto detects the sheet thickness. At this time, the controller 47 recognizes the paper thickness T based on the detection result of the paper thickness detection sensor.

  Next, the control unit 47 determines whether or not the paper thickness T detected by using the paper thickness detection sensor exceeds a preset first reference thickness T1 (step S3). If the sheet thickness T exceeds the first reference thickness T1, the seating position is set to the “weak” position (step S4).

  If the sheet thickness T does not exceed the first reference thickness T1, it is determined whether or not the sheet thickness T is less than a preset second reference thickness T2 (step S5). . If the sheet thickness T is equal to or greater than the second reference thickness T2, the seating position is set to the “medium” position (step S6). If the sheet thickness T is less than the second reference thickness T2, the seating position is set to the “strong” position (step S7).

  Incidentally, the magnitude relationship between the first reference thickness T1 and the second reference thickness T2 is set under the condition of T1> T2. Assuming that the paper types are classified into three types of “thick paper”, “plain paper”, and “thin paper” depending on the thickness of the paper, the first reference value T1 and the second reference value T2 are used. Is a threshold value for determining whether the paper whose thickness is detected by the paper thickness detection sensor corresponds to “thick paper”, “plain paper”, or “thin paper”. In this case, when the paper type is determined to be “thick paper”, the seating position is set to the “weak” position. If the paper type is determined to be “plain paper”, the seating position is set to “medium”, and if the paper type is determined to be “thin paper”, the seating position is set to the “strong” position. It will be.

  Subsequently, the width of the sheet is detected by the sheet width detection sensor 35 during the sheet conveyance (step S8). At this time, the control unit 47 recognizes the paper width W based on the detection result of the paper width detection sensor 35. Incidentally, it is not always necessary to detect the sheet width numerically. For example, as the sheet width detection sensor 35, a plurality of photosensors are arranged in a direction orthogonal to the sheet conveyance direction, and the sheet width detection sensor is arranged in the sheet conveyance direction. The width W of the paper may be recognized based on the on / off state of each photo sensor when the paper passes the detection position 35.

  Next, the control unit 47 determines whether or not the paper width W detected using the paper width detection sensor 35 exceeds a preset first reference width W1 (step S9). If the paper width W exceeds the first reference width T1, the motors 45A and 45E are driven to move the seating members 39A and 39E from the retracted position to the seated position (step S10).

  At this time, if the seating position has been set to the “weak” position in the processing of steps S2 to S7, the seating members 39A, 39E, 39E is moved from the “retracted” position to the “weak” position. If the seating position is set to the “middle” position, the seating members 39A and 39E are moved from the “retracted” position to the “middle” position according to this setting, and the seating position is set to “ If it is set to the “strong” position, the seating members 39A and 39E are moved from the “retracted” position to the “strong” position according to this setting.

  If the paper width W does not exceed the first reference width W1, it is determined whether the thickness width of the paper is less than a preset second reference width W2 (step S11). If the paper width W is equal to or larger than the second reference width W2, the motors 45B and 45D are driven to move the seating members 39B and 39D from the retracted position to the seated position (step S12). Further, when the seating position is set to the “weak” position in the processing of steps S2 to S7, the seating members 39B and 39D are moved from the “retracted” position to the “weak” position according to this setting. When the waist position is set to the “middle” position, the waist members 39B and 39D are moved from the “retracted” position to the “middle” position according to this setting, and the waist position is set. Is set to the “strong” position, the seating members 39B and 39D are moved from the “retracted” position to the “weak” position according to this setting.

  On the other hand, if the paper width W is less than the second reference width W2, the motor 45C is driven to move the seating member 39C from the retracted position to the seated position (step S13). Further, when the seating position is set to the “weak” position in the processing of steps S2 to S7, the seating member 39C is moved from the “retracted” position to the “weak” position according to this setting. If the seating position is set to the “middle” position, the seating member 39C is moved from the “retracted” position to the “middle” position according to this setting, and the seating position is set to “strong”. If it is set to the position, the seating member 39C is moved from the “retracted” position to the “strong” position according to this setting.

  Incidentally, the magnitude relationship between the first reference width W1 and the second reference width W2 is set under the condition of W1> W2. Further, with respect to the inter-roll distances L1 and L2 shown in FIG. 2, the first reference width W1 is set to the same dimension as the first inter-roll distance L1, and the second reference width W2 is the second roll. The same dimension as the distance L2 is set.

  Assuming that the paper types are classified into three types of “wide paper”, “medium width paper”, and “narrow paper” depending on the difference in paper width, the first reference width W1 and the second reference width W1. The width W2 is a threshold value for determining whether the paper whose width is detected by the paper width detection sensor 35 corresponds to “wide paper”, “medium width paper”, or “narrow paper”. . In this case, if the paper type is determined to be “wide paper”, the seating members 39A and 39E are moved to the seating position. If the paper type is determined to be “medium width paper”, the seating members 39B and 39D are moved to the seating position, and if the paper type is determined to be “narrow paper”, the seating member 39C is set to the seating position. Will be moved to.

  Thereafter, the paper on which image formation on one side or both sides has been completed is discharged by the paper discharge unit 26 according to the rotation of the discharge roll 29 (step S14). At that time, as shown in FIG. 8A, the paper having a paper width wider than the first reference width W1 is brought into contact with the seating members 39A and 39E arranged in the seating position in the paper width direction. It is discharged at two places. Further, as shown in FIGS. 8B and 8C, a sheeting member in which the sheet width is equal to or less than the first reference width W1 and equal to or greater than the second reference width W2 is disposed at the position where the sheet is positioned. By contact with 39B and 39D, the paper is discharged with two waists in the paper width direction. Further, as shown in FIG. 8D, a sheet having a sheet width less than the second reference width W2 is stretched at one position in the sheet width direction by contact with the seating member 39C arranged at the seating position. Will be discharged.

  Further, a sheet having a sheet thickness greater than the first reference thickness T1 is seated with a relatively weak force because the seating member is disposed at the “weak” position. Further, a sheet having a sheet thickness of not more than the first reference thickness T1 and not less than the second reference thickness T2 has a relatively medium force because the seating member is disposed at the “medium” position. The sheet having a thickness less than the second reference thickness T2 is seated with a relatively strong force because the seating member is disposed at the “strong” position.

  The seating members 39A, 39B, 39C, 39D, and 39E are selected according to the sheet thickness detected by the sheet thickness detection sensors 32, 33, and 34 and the sheet width detected by the sheet width detection sensor 35. As a form of movement control when moving from the retracted position to the sitting position, various forms can be adopted. For example, when the paper width W detected by the paper width detection sensor 35 is wider than the first reference width W1, each waist is detected according to the paper thickness detected by the paper thickness detection sensors 32, 33, and 34. The positions of the attaching members 39A, 39B, 39C, 39D, and 39E may be controlled by adopting any one of a plurality of combination examples as shown in FIG.

  When the paper width W detected by the paper width detection sensor 35 is equal to or smaller than the first reference width W1 and equal to or larger than the second reference width W2, the thickness of the paper detected by the paper thickness detection sensors 32, 33, and 34 is detected. Accordingly, the position of each of the seating members 39B, 39C, 39D may be controlled by adopting any one of a plurality of combination examples as shown in FIG. When the paper width W detected by the paper width detection sensor 35 is less than the second reference width W2, the seating member 39C is used according to the thickness of the paper detected by the paper thickness detection sensors 32, 33, and 34. The position may be controlled by adopting any one of a plurality of combination examples as shown in FIG.

  Further, when transporting a sheet (for example, an envelope) having a non-uniform thickness in a direction orthogonal to the sheet transport direction, the seating member that contacts the relatively thick part of the sheet is “weak”. By placing it in the position, it is seated with a relatively weak force (small protruding amount), and the seating member that is in contact with the relatively thin part of the paper is placed in the “medium” or “strong” position. Thus, the movement positions of the respective seating members may be controlled so that the seating is performed with a relatively strong force.

  Further, by accepting an operator's input designation on the operation display unit 36 of the image forming apparatus, it is possible to arbitrarily set the seating conditions of the sheets by the respective seating members 39A, 39B, 39C, 39D, and 39E. Good. FIG. 11 is a diagram illustrating an example of an operation screen (backing condition setting screen) displayed on the operation display unit 36 when setting the waisting condition. Here, it is assumed that the display unit of the operation display unit 36 is a display with a touch panel. In the setting screen for the seating condition shown in the figure, the setting of the seating condition can be performed by entering the paper thickness and paper width numerically or by selecting the desired paper thickness and width from the pull-down menu (not shown). It is possible to input and specify the thickness and width of the paper to be performed.

  Further, when the operator specifies the thickness and width of the sheet on the setting screen, the movement positions of the respective seating members 39A, 39B, 39C, 39D, and 39E based on the seating conditions prepared as standard settings in advance. Is displayed as one of “evacuation”, “weak”, “medium”, and “strong”. In the illustrated example, “A” is “backing member 39A”, “B” is “backing member 39B”, “C” is “backing member 39C”, “D” is “backing member 39D”, “E”. "Corresponds to" backing member 39E ". Further, with the standard settings based on the thickness and width of the paper specified by the operator, the movement positions of the seating members 39A and 39E are the “retracted” position, and the movement positions of the seating members 339B and 39D are the “medium” positions. This shows a situation where the position of the seating member 39C is set to the “weak” position.

  Under such a setting situation, the operator can move the seating members 39A, 39B, 39C, 39D, and 39E according to his / her own desires as “retract”, “weak”, “medium”, By selecting (pressing) any one of the operation buttons indicating the characters “strong”, the movement position of the corresponding seating member is selected by the operator from the standard setting position. It can be changed to. Then, after the operator has set the positions of the respective seating members 39A, 39B, 39C, 39D, and 39E to desired positions, the operator presses the “OK” button in the setting screen, thereby The setting (change) of the movement position is fixed. When the “cancel” button in the setting screen is pressed, the movement positions of the respective seating members 39A, 39B, 39C, 39D, and 39E are returned to the standard settings.

  FIG. 12 is a flowchart applied to the control processing of the control unit 47 when performing double-sided image forming processing for forming images on both sides of a sheet.

  First, before the control unit 47 sends the sheet on which the image is formed on the first surface via the image transfer unit 18 and the image fixing unit 19 to the discharge roll 29 via the reverse roll 14, The attaching members 39A, 39B, 39C, 39D, and 39E are selectively moved from the retracted position to the seated position under the first condition (step S21).

  Next, the control unit 47 rotates the reversing roll 14 and the discharge roll 26 in the normal direction, thereby discharging a part of the sheet on which the image is formed on the first surface to the outside of the machine (on the second discharge tray) In this state, the rotation of the reverse roll 14 and the discharge roll 29 is stopped (steps S22 and S23).

  Next, the control unit 47 moves the seating member moved to the seating position in step S21 to the retracted position (step S24). As a result, all the seating members 39A, 39B, 39C, 39D, and 39E are returned to the initial positions (retracted positions).

  Next, the control unit 47 reversely rotates the reversing roll 14 and the discharge roll 29, thereby drawing the paper into the apparatus and feeding the paper from the reverse roll 14 to the discharge roll 15 (step S25).

  After that, the controller 47 passes the paper on which the image is formed on the second surface through the image transfer unit 18 and the image fixing unit 19 before feeding the paper to the discharge roll 29 via the reverse roll 14. The attaching members 39A, 39B, 39C, 39D, and 39E are selectively moved from the retracted position to the seated position under a second condition different from the first condition (step S26).

  Next, the control unit 47 rotates the reversing roll 14 and the discharge roll 26 in the forward direction, and discharges all of the paper on which the image is formed on the second surface (both sides) to the outside (on the second discharge tray). (Step S27).

  The first condition and the second condition are appropriately set according to the sheet thickness detected by the sheet thickness detection sensors 32, 33, and 34 and the sheet width detected by the sheet width detection sensor 35 as described above. Is. For example, in the first condition, the seating members 39B, 39C, and 39D are moved from the “retracted” position to the “strong” position, and in the second condition, the seating members 39A, 39E that are different from the first condition are used. Is set to move from the “retracted” position to the “strong” position. As another example, in the first condition, the seating members 39A, 39E are moved from the “retracted” position to the “weak” position, and in the second condition, the seating members 39A, 39C, 39E are moved. The position is set so as to move from the “evacuation” position to a “strong” position different from the first condition.

  In the above-described embodiment, the position of each of the seating members 39A, 39B, 39C, 39D, and 39E can be switched between four levels of “retraction,“ weak ”,“ medium ”, and“ strong ”. However, the present invention is not limited to this, for example, a configuration that can be switched to three levels of “weak”, “medium”, and “strong”, or three levels of “evacuation”, “weak”, and “strong” A configuration that can be switched to two levels of "evacuation" and "strong" or two levels of "strong" and "weak", or a configuration that can be switched to multiple levels of five or more levels.

  Further, not only the paper discharge unit 26 but also the other paper discharge units 25 and 27 can have the same configuration as the paper discharge unit 26.

  Furthermore, in the above-described embodiment, as the configuration of the discharge roll 29, the drive roll 29A is arranged on the upper side and the driven roll 29B is arranged on the lower side, but the present invention is not limited to this, and as shown in FIG. In addition, when the positional relationship between the drive roll 29A and the driven roll 29B is reversed upside down, that is, the drive roll 29A is disposed on the lower side and the driven roll 29B is disposed on the upper side, the same applies.

1 is a schematic diagram illustrating a configuration of an electrophotographic image forming apparatus according to an embodiment of the present invention. FIG. 6 is a diagram illustrating a configuration example of a paper discharge unit. It is a figure which shows an example of the drive mechanism for moving a waisting member. It is a perspective view which shows the arrangement | positioning state of a waisting member and a drive mechanism. It is a figure which shows the movement position of a waisting member. FIG. 2 is a block diagram illustrating a configuration example of a control system of the image forming apparatus according to the embodiment of the present invention. It is a flowchart which shows an example of the control processing performed by a control part. It is a figure which shows the relationship between the position of a several seating member, and paper width. It is a figure (the 1) which shows the example of a form of movement control of a several backrest member. It is FIG. (2) which shows the example of a form of movement control of a several backrest member. It is a figure which shows the example of a display of the setting screen of a seating condition. 7 is a flowchart applied to control processing of a control unit when performing double-sided image forming processing for forming images on both sides of a sheet. It is a figure which shows the other example of arrangement | positioning of a discharge roll.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 14 ... Reverse roll, 18 ... Image transfer part, 19 ... Image fixing part, 25, 26, 27 ... Paper discharge part, 28, 29, 30 ... Discharge roll, 32, 33, 34 ... Paper thickness detection sensor, 35 ... Paper Width detection sensor 36 ... operation display unit 39, 39A to 39E ... seating member, 40 ... drive mechanism, 45, 45A to 45E ... motor

Claims (2)

Image forming means for forming an image on paper;
A discharge roll for discharging the paper on which the image is formed by the image forming means;
A plurality of seating members provided at predetermined intervals in a direction perpendicular to the paper transport direction in order to seat the paper ejected by the ejection roll;
In a double-sided image forming process in which images are formed on both sides of a plurality of driving means and a plurality of driving means for individually moving the plurality of seating members in a direction intersecting the paper surface of the paper discharged by the discharge roll , an image on the first surface When a part of the paper on which the sheet is formed is discharged out of the apparatus by the discharge roll, the plurality of seating members are selectively moved from the retracted position to the seated position under the first condition, and the second surface When the sheet on which the image is formed is discharged out of the apparatus by the discharge roll, the plurality of seating members are selectively moved from the retracted position to the seated position under a second condition different from the first condition. images forming apparatus characterized by comprising a control means for controlling said plurality of drive means so as to move to. Before SL control means, in the double-sided image forming process, the sheet part of the image on the first surface is formed paper after the discharged outside by the discharge roll, and by the reverse rotation of the discharge roller the before pulling on board, the plurality of stiffness enhancing image forming apparatus according to claim 1, wherein the controller controls so as to move all the retracted position of the member.

Images