JP2018008789A - Sheet loading device and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet loading device which can easily set the fixation position of a regulation member regulating the loading position of the sheet without adjustment.SOLUTION: A cassette 10 is loaded with sheets. Sheet width regulation plates 104a, 104b regulate the loading position of the sheets loaded on the cassette 10. A pinion gear 122 can set the assembly state of the sheet size variable type and the assembly state of the sheet size fixed type. In the assembly state of the sheet size variable type, the regulation positions by the sheet width regulation plates 104a, 104b can be selected. On the other hand, in the assembly state of the sheet size fixed type, the regulation positions by the sheet width regulation plates 104a, 104b cannot be selected.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a sheet stacking apparatus that stacks sheets.

  2. Description of the Related Art A sheet stacking apparatus that uses a pair of opposing regulating members to regulate both end faces in the width direction perpendicular to the conveyance direction of stacked sheets is used. Patent Document 1 discloses a cassette as a sheet stacking apparatus for supplying sheets to an image forming unit of an image forming apparatus. Here, a pair of rack gears fixed to a pair of restricting members opposed to each other in the width direction orthogonal to the sheet conveying direction are meshed with one pinion gear, and the pair of restricting members that restrict the sheet end surface are It moves in conjunction with the direction. A sheet size variable cassette (universal cassette) that can be easily stacked corresponding to sheets of different sizes is known.

  By the way, the selection frequency of the size of the sheets to be stacked may be biased to one type of size such as A4 vertical feeding size in the region. For such a case, there is a sheet size fixing cassette that fixes the position of the regulating member in the width direction according to the size of one kind of sheet that is frequently used from the beginning.

JP-A-6-234432

  Here, in the sheet size fixing cassette, the restriction member is screw-fixed to the cassette so that the restriction member cannot be moved. However, the fixing position of the restriction member varies within a tolerance. Due to the variation in the fixed position, there may be a difference in the interval between the stacked sheet end and the regulating member in the sheet size variable cassette in which the regulating member has the engagement play between the pinion gear and the rack gear. For this reason, if a separating member or the like on the downstream side in the feeding direction is arranged in accordance with one cassette, the other cassette may affect the feeding performance. Therefore, in order to deal with such a problem, in the sheet size fixing cassette, the fixing position of the regulating member is individually adjusted, which increases the number of assembly steps and leads to an increase in cost.

  An object of the present invention is to provide a sheet stacking apparatus that can be easily set without adjusting a fixed position of a regulating member that regulates the stacking position of sheets.

  The sheet stacking apparatus of the present invention includes a stacking unit on which sheets are stacked, a pair of regulating units that regulate the stacking position of the sheets stacked on the stacking unit, and a regulation position that can be selected by the pair of regulating units. Setting means capable of setting a first state and a second state in which the selection by the pair of restricting means is disabled.

  According to the present invention, it is possible to easily set without adjusting the fixing position of the restricting member that restricts the sheet stacking position.

1 is an explanatory diagram of a configuration of an image forming apparatus. It is explanatory drawing of the structure of the cassette by a perspective view. It is explanatory drawing of the interlocking mechanism of the sheet | seat width control board by a top view. It is explanatory drawing of the cassette of the comparative example by a top view. 3 is an explanatory diagram of a structure of a pinion gear in the cassette according to Embodiment 1. FIG. (A) is a surface used as a sheet size variable type, and (b) is a surface used as a sheet size fixed type. It is explanatory drawing of the assembly state of an interlocking mechanism. (A) is a method of assembling a sheet size variable type, and (b) is a method of assembling a fixed sheet size type. It is explanatory drawing of the structure of the pinion gear in the cassette of Embodiment 2. It is explanatory drawing of the assembly state of an interlocking mechanism. (A) is a method of assembling a sheet size variable type, and (b) is a method of assembling a fixed sheet size type.

  Embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Embodiment 1>
(Image forming device)
FIG. 1 is an explanatory diagram of the configuration of the image forming apparatus. As shown in FIG. 1, an image forming apparatus 1 is an electrophotographic monochrome printer in which a sheet supply unit 2 which is an example of an embodiment of the present invention is incorporated. The image forming apparatus 1 is a so-called vertical conveyance type in which the image forming unit 3 is disposed above the sheet supply unit 2 and the fixing device 18 is disposed above the image forming unit 3.

  The image forming unit 3 forms an image on a sheet fed from a cassette 10 which is an example of a sheet stacking apparatus. The image forming unit 3 surrounds the photosensitive drum 15 and includes a charging roller 14, an exposure device 13, a developing device 16, a transfer roller 17, and a drum cleaning device 15a. The photosensitive drum 15 has a photosensitive layer and rotates. The charging roller 14 is charged with a charging voltage to charge the surface of the photosensitive drum 15 to a uniform potential.

  The exposure device 13 scans the laser beam to form an electrostatic latent image of the image on the surface of the photosensitive drum 15. The developing device 16 carries the toner on the developing roller 16a and conveys the toner to a portion facing the photosensitive drum 15, and develops the electrostatic latent image on the photosensitive drum 15 into a toner image. The transfer roller 17 is applied with a transfer voltage and transfers the toner image on the photosensitive drum 15 onto the sheet fed from the sheet supply unit 2 to the transfer unit T1. The drum cleaning device 15a collects residual toner by sliding the cleaning blade against the photosensitive drum 15.

  The sheet supply unit 2 takes out sheets one by one from the cassette 10 and feeds them to the transfer unit T1. The sheet on which the toner image has been transferred in the transfer unit T1 is conveyed to the fixing device 18 disposed above the image forming unit 3, and the toner image is melted in the process of being nipped and conveyed by the heating nip portion N2, thereby forming an image. It is fixed. The fixing device 18 forms a heating nip portion N2 by pressing the pressure roller 18b against a heating unit 18a using a heating belt. The stacking tray 19 has a substantially horizontal stacking surface disposed on the top surface of the image forming apparatus 1. The sheet on which the image is fixed is discharged from the fixing device 18 to the stacking tray 19 through the discharge roller 21 and stacked.

(Sheet supply unit)
The image forming apparatus 1 includes a cassette 10 that is an example of a sheet stacking apparatus that stores sheets. The cassette 10 is attached to the lower part of the main body of the image forming apparatus 1 so that it can be inserted into and removed from the front side. The sheets stored in the cassette 10 are supplied to the image forming unit 3 one by one by the half-moon feeding roller 101 and the separating unit 106.

  The cassette 10 stacks and stores sheets on the stacking plate 102. The front end side of the stacking plate 102 which is the swinging side portion is pushed up toward the half-moon feeding roller 101 by the biasing force of the compression spring 103 disposed so as to bias upward from the lower surface side. The compression spring 103 lifts the sheet stacked on the stacking plate 102 and brings the uppermost sheet into contact with the separation claw 105 (105a, 105b: FIG. 2).

  A half-moon paper feed roller 101 is provided at an obliquely upper position in the front end portion of the cassette 10 in the paper feed direction. The half-moon feeding roller 101 pulls out the sheet from the cassette 10 and delivers it to the separation unit 106. The sheet fed from the cassette 10 by the half-moon paper feed roller 101 is conveyed to the registration roller 107 through the separation unit 106.

  The separation unit 106 pulls back the multi-feed sheet fed to the top sheet to the cassette 10 while transporting the top sheet to the registration roller 107 by the transport nip N1 in which the retard roller is brought into contact with the transport roller. .

  The registration roller 107 sends the sheet to the transfer portion T1 in synchronization with the toner image on the photosensitive drum 15. A registration sensor (not shown) is disposed immediately before the registration roller 107. When the leading edge of the sheet is detected by the registration sensor, the registration roller 107 is stopped for a predetermined time, whereby an appropriate loop is formed on the sheet, and the skew state of the sheet is corrected. Thereafter, when the registration roller 107 starts to rotate at an appropriate timing, the registration roller 107 is driven to rotate and is conveyed to the transfer unit T1 with the leading edge of the sheet aligned. In the transfer portion T1, the toner image on the photosensitive drum 15 is transferred to the sheet by the transfer action of the transfer roller 17.

(cassette)
FIG. 2 is an explanatory diagram of a configuration of a cassette as a sheet stacking apparatus according to a perspective view. FIG. 3 is an explanatory view of the interlocking mechanism of the sheet width regulating plate according to a plan view. As shown in FIG. 2, a sheet is stacked / held on a stacking plate 102, which is an example of a stacking unit. Inside the cassette 10, the stacking plate 102 is disposed so as to form an inclined surface. The front end portion of the stacking plate 102 swings in the vertical direction around the rear end edge portion in the sheet conveying direction.

  The sheet width regulating plates 104a and 104b, which are an example of a pair of regulating means, regulate the stacking position of the sheets stacked on the stacking plate 102. When the sheet width regulating plates 104a and 104b supply the sheet to the image forming unit 3 shown in FIG. 1, the sheet width direction center coincides with the image forming center in the rotation axis direction of the photosensitive drum 15. The cassette 10 shown in FIG. 2 includes sheet width regulating plates 104a and 104b that regulate the end faces in the sheet width direction. The sheet width regulating plates 104a and 104b are assembled so as to be movable in the sheet width direction with the stacking plate 102 sandwiched in the sheet width direction.

  Separation claws 105a and 105b are provided at the front end portions of the sheet width regulating plates 104a and 104b. The separation claws 105a and 105b are configured so as to suppress the corner portions at both ends of the sheet. As shown in FIG. 1, when the half-moon feeding roller 101 is rotationally driven in the direction of the arrow, the half-moon feeding roller 101 pulls out the sheet from the cassette 10 while the stacking plate 102 on which the sheets are stacked is pushed down to a predetermined height. . At this time, the sheets are separated one by one by the separating action of the separation claws 105a and 105b arranged at the sheet feeding portion (left end portion) of the cassette 10 shown in FIG.

  As shown in FIG. 2, sheet width regulating plates 104a and 104b are arranged inside the sheet size variable type cassette 10 so as to contact both side end surfaces in the direction of arrow C, which is the sheet width direction. As shown in FIG. 3, the sheet width regulating plates 104a and 104b are in contact with both side end surfaces in the width direction of the sheets and align the edges in the width direction of the stacked sheets.

  As shown in FIG. 3, the sheet width regulating plates 104a and 104b are attached on the substrate 123 so as to be movable in the direction of arrow C. The sheet width regulating plates 104a and 104b can easily adjust the facing distance when manually operated by the user. The user sets the facing interval between the sheet width regulating plates 104a and 104b according to the size of the sheet to be accommodated in the cassette 10.

  In the cassette 10, a rack gear and pinion gear interlocking mechanism 5 is provided on the sheet width regulating plates 104a and 104b. The pinion gear 122 moves the sheet width restricting plates 104a and 104b symmetrically in conjunction with each other. The pinion gear 122 is a rotating member provided with a pinion gear that meshes with a rack gear 120a that is an example of a first rack gear and a rack gear 120b that is an example of a second rack gear. The pinion gear 122, which is an example of setting means, can select and set the assembly state of the sheet size variable type which is an example of the first state and the assembly state of the sheet size fixed type which is the second state.

  In the assembled state of the sheet size variable type, the restriction position by the sheet width restriction plates 104a and 104b can be selected. In the assembled state of the sheet size variable type, the sheet width regulating plates 104a and 104b can be moved in conjunction with each other. On the other hand, in the assembly state of the fixed sheet size type, the restriction position cannot be selected by the sheet width restriction plates 104a and 104b. In the assembly state of the fixed sheet size type, the sheet width regulating plates 104a and 104b are fixed at a predetermined facing interval.

  The sheet width regulating plates 104a and 104b are moved symmetrically in the width direction of the sheet P by being interlocked by the interlocking mechanism 5. The sheet width regulating plate 104a is connected to the rack gear 120a. The sheet width regulating plate 104b is connected to the rack gear 120b. The rack gear 120a and the rack gear 120b mesh with the common pinion gear 122.

  The rack gear 120a has a position holding portion 121a that elastically engages with the positioning grooves 124a and 125a to set the position of the sheet width regulating plate 104a. The positioning groove 124a corresponds to the letter size, and the positioning groove 125a corresponds to the restriction position of the A4 size longitudinal feeding sheet.

  The rack gear 120b has a position holding portion 121b that elastically engages with the positioning grooves 124b and 125b to set the position of the sheet width regulating plate 104b. The positioning groove 124b corresponds to the restriction position of the letter size, and the positioning groove 125b corresponds to the restriction position of the A4 size longitudinal feeding sheet.

  Since the position holding portions 121a and 121b are easily bent as the sheet width restriction plates 104a and 104b move, the position holding portions 121a and 121b do not prevent the user from moving the sheet width restriction plates 104a and 104b manually. The opposing widths of the sheet width regulating plates 104a and 104b are adjusted with a click feeling by the position holding portions 121a and 121b.

(Comparative example)
FIG. 4 is an explanatory view of a cassette of a comparative example in plan view. FIG. 4 is a plan view illustrating the attachment state of the sheet width regulating plates 104a and 104b in the sheet size fixed type cassette 10K of the comparative example, corresponding to FIG.

  By the way, for example, an A4 size printer may use only an A4 size sheet depending on the model and sales area. In this case, there is no need to change the positions of the sheet width regulating plates 104a and 104b.

  For this reason, in a model or region that uses only A4 size sheets, as shown in FIG. 4, a sheet size fixed type cassette in which the sheet width regulating plates 104a and 104b are fixed to the bottom plate 128 of the cassette 10 so that they cannot be moved. 10K is adopted.

  As shown in FIG. 4, the cassette 10 </ b> K of the comparative example is a cassette dedicated to A4 size shipped to an area where it is not necessary to change the sheet size. In the cassette 10K of the comparative example, the sheet width regulating plates 104a and 104b are directly fixed to the bottom plate 128 of the cassette 10 by inserting screws 119b into the width regulating plate holes 119.

  Since the cassette 10K is fixed by the screws 119b, the sheet width regulating plates 104a and 104b are free from minute backlash.

  In the sheet size variable type cassette 10, some backlash occurs in the interlocking mechanism 5. On the other hand, since the fixed sheet size cassette 10K is fixed by screws 119b, the amount of play of the sheet width regulating plates 104a and 104b differs compared to the variable sheet size cassette 10. Come.

  The sheet size fixed type cassette 10K has less margin for sheet feeding performance than the sheet size variable type cassette 10 because the sheet width regulating plates 104a and 104b do not have moderate play. The difference in the play amount of the sheet width regulating plates 104a and 104b greatly affects the sheet separation performance because the degree of engagement between the separation claws 105a and 105b and the sheet corners is different.

  As a result, in the sheet size variable type cassette 10 and the sheet size fixed type cassette 10K, even if the physical positions of the sheet width regulating plates 104a and 104b are the same, only one of the sheet feeding defects occurs. May be easier. In the cassette 10K of the comparative example, the sheet feeding performance varies more greatly between the cassettes 10K than the cassette 10 of the variable sheet size type.

  For this reason, it is necessary to adjust the mounting of the sheet width regulating plates 104a and 104b in a state where the fixed sheet size type cassette 10K is installed for each of the image forming apparatuses 1, which increases the number of assembling steps and the assembling cost. It is getting bigger.

  Therefore, in the first embodiment, in the sheet size variable type cassette 10, the pinion gear 122 can be reversed and attached to be changed to the sheet size fixed type.

(Pinion gear)
FIG. 5 is an explanatory diagram of the structure of the pinion gear in the cassette according to the first embodiment. FIG. 6 is an explanatory diagram of the assembled state of the interlocking mechanism. In FIG. 5, (a) is a surface used as a sheet size variable type, and (b) is a surface used as a sheet size fixed type. In FIG. 6, (a) shows how to assemble a variable sheet size type, and (b) shows how to assemble a fixed sheet size type. FIG. 6 is a bottom view of the interlocking mechanism 5 of FIG. 3 and illustrates the interlocking mechanism 5 with the substrate 123 omitted from the lower surface side of the substrate 123 indicated by a broken line.

  As shown in FIG. 3, the pinion gear 122 is inserted into a rotating shaft 123 j provided on the substrate 123 of the cassette 10 with the surface on which the meshing teeth are disposed facing down. The pinion gear 122 is rotatably attached with one touch by inserting a ring having an elastic engagement claw (patching claw) 127 into the rotation shaft 123j.

  As shown in FIGS. 5A and 5B, the pinion gear 122 has meshing teeth on both sides. As shown in FIG. 5A, the entire surface of the surface A, which is one side of the pinion gear 122 used as a variable seat size type, has a gear shape 126. As shown in FIG. 5B, the surface B which is one side of the pinion gear 122 used as the fixed sheet size type has partial gear shapes 126a and 126b.

  As shown in FIG. 6A, the gear shape 126 of the pinion gear 122 meshes with the rack gear 120a fixed to the seat width regulating plate 104a and the rack gear 120b fixed to the seat width regulating plate 104b. . For this reason, the sheet width regulating plates 104a and 104b move symmetrically while being interlocked.

  In the assembled state of the sheet size variable type shown in FIG. 6A, the entire peripheral tooth surface side of one surface A of the pinion gear 122 shown in FIG. 5A is meshed with the rack gears 120a and 120b. As a result, the pinion gear 122 can rotate, the rack gears 120a and 120b meshing with the pinion gear 122 can move freely, and the sheet width regulating plates 104a and 104b fixed to the rack gears 120a and 120b can also move freely. Can do.

  As shown in FIG. 5B, in the first embodiment, the other surface B of the pinion gear 122 is used as a fixed sheet size type. A pinion gear is disposed on one surface A of the pinion gear 122, and a pinion gear boss 131 is disposed on the other surface B of the pinion gear 122. The gear shapes 126 a and 126 b are formed only on a part of the entire circumference of the pinion gear 122. The gear shapes 126a and 126b of the pinion gear 122 are formed excluding the crossing region of the pinion gear 122 including the pinion gear boss 131 and the center.

  As shown in FIG. 6B, the pinion gear boss 131 and the hole 123a can fix the pinion gear 122 in a state where a predetermined facing distance is set to the sheet width regulating plates 104a and 104b. The pinion gear boss 131 is an example of an engaging means provided on the pinion gear 122. The hole 123 a is an example of an engaging portion provided in the cassette 10 (substrate 123) so as to engage with the pinion gear boss 131. The pinion gear boss 131 can fix the pinion gear 122 by engaging with the substrate 123.

  The pinion gear 122 is restricted from rotating with respect to the substrate 123 by inserting a pinion gear boss 131 into a hole 123 a formed in the substrate 123. The pinion gear 122 whose rotation is restricted meshes the gear shapes 126a and 126b with the rack gears 120a and 120b, respectively, and restricts the movement of the sheet width restriction plates 104a and 104b in the width direction of the sheet.

  6B, the pinion gear boss 131 is restrained in the hole 123a of the substrate 123, and the pinion gear 122 cannot be rotated on the substrate 123. The pinion gear 122 meshes the partial gear shapes 126a and 126b with the rack gears 120a and 120b, and the rack gears 120a and 120b are positioned and fixed at opposing intervals of the A4 size longitudinal sheet width.

  In the cassette 10 according to the first embodiment, a pinion gear 122 and a pair of rack gears 120a and 120b that are engaged with each other with the pinion gear 122 interposed therebetween constitute an interval adjusting mechanism for the sheet width regulating plates 104a and 104b. Depending on the mounting direction of the pinion gear 122, it is possible to freely select whether the sheet width regulating plates 104a and 104b are movable or fixed.

(Effect of Embodiment 1)
In the first embodiment, the sheet size fixed type and the sheet size variable type can be easily switched depending on the mounting direction of the pinion gear 122. The fixed sheet size type and the variable sheet size type can be assembled in the same work procedure using the same components. There is no need to design, manufacture, and stock dedicated parts with different designs for the fixed sheet size type and the variable sheet size type. Assembling the cassette 10 to which the sheet width regulating plates 104a and 104b are fixed is a simple operation that does not require adjustment.

  In the first embodiment, when the pinion gear 122 is attached, the amount of play of the sheet width regulating plates 104a and 104b is set to be equal between the sheet size variable type and the sheet size fixed type. For this reason, a difference in sheet feeding performance hardly occurs between the sheet size variable type and the sheet size fixed type. Between the sheet size variable type cassette 10 and the sheet size fixed type cassette 10, the sheet width regulating plates 104 a and 104 b can ensure substantially the same regulation performance at the end portions in the sheet width direction. It is possible to reproduce the regulation performance at the end of the sheet in the width direction by the sheet width regulating plates 104a and 104b, such as the sheet stacking state and the sheet drawing resistance.

  In the first embodiment, there is one hole 123a formed in the substrate 123 into which the pinion gear boss 131 is inserted. However, a plurality of holes 123a may be provided in consideration of workability for insertion. Further, the gear shapes 126a and 126b on the other surface B of the pinion gear 122 are formed only on a part of the entire circumference of the pinion gear 122, but the gear shape is not limited to a part and may be the entire circumference. This is because the pinion gear 122 on the surface B is required to mesh with the rack gear and not rotate.

  In the first embodiment, the cassette 10 can be easily switched between the sheet size variable type and the sheet size fixed type depending on the direction of the pinion gear 122 that can be easily detached and reassembled. For this reason, a service person or an operator can easily switch the type of cassette in the market.

<Embodiment 2>
In the first embodiment, as shown in FIG. 6B, the cassette 10 is switched between the variable sheet size type and the fixed sheet size type by assembling the interlocking mechanism 5 by turning the pinion gear 122 upside down. On the other hand, in the second embodiment, as shown in FIGS. 7 and 8, the interlock mechanism 5 is assembled by rotating the pinion gear 122 by 180 degrees without reversing the front and back, so that the variable sheet size type and the seat Switch between fixed size type. The cassette 10 of the second embodiment is configured in the same manner as the cassette 10 of the first embodiment, except that the mounting structure of the pinion gear 122 on the substrate 123 is different. Therefore, in FIG. 7 and FIG. 8, the same reference numerals as those in FIG. 5 and FIG.

(Pinion gear)
FIG. 7 is an explanatory diagram of the structure of the pinion gear in the cassette according to the second embodiment. FIG. 8 is an explanatory diagram of the assembled state of the interlocking mechanism. In FIG. 8, (a) shows how to assemble a variable sheet size type, and (b) shows how to assemble a fixed sheet size type. FIG. 8 is a bottom view of the interlocking mechanism 5 of FIG. 3 and illustrates the interlocking mechanism 5 with the substrate 123 omitted from the lower surface side of the substrate 123 indicated by a broken line.

  As shown in FIG. 7, in the second embodiment, a gear shape 126 and a pinion gear boss 133 are arranged on one surface of the pinion gear 122. In the pinion gear 122, a pinion gear boss 133 is formed on the gear shape 126.

  As shown in FIG. 8A, the cassette 10 has a hole 123h and a guide groove 123m in which the pinion gear boss 133 can be engaged and the movable range of the pinion gear boss 133 is different. That is, a hole 123 h and a guide groove 123 m into which the pinion gear boss 133 of the pinion gear 122 can be inserted are formed in the substrate 123 of the cassette 10.

  That is, the pinion gear boss 133 as an example of the pinion gear and the engaging means is disposed on the same surface of the pinion gear 122 as an example of the setting means. And the guide groove 123m which is an example of an avoidance part, and the hole 123h which is an example of an engaging part are arrange | positioned at the board | substrate 123 which is an example of a stacking part. The guide groove 123m avoids engagement with the pinion gear boss 133 so as to set an assembly state of a sheet size variable type which is an example of the first state. The hole 123h engages with the pinion gear boss 133 so as to set an assembly state of a fixed sheet size type which is an example of the second state.

  In the assembled state of the sheet size variable type shown in FIG. 8A, the pinion gear boss 133 of the pinion gear 122 is inserted into the guide groove 123 m of the substrate 123. For this reason, the pinion gear 122 is rotatable about the rotation shaft 123j with respect to the substrate 123 within a range in which the pinion gear boss 133 is guided by the guide groove 123m. The gear shape 126 of the pinion gear 122 meshes with the rack gear 120a fixed to the sheet width regulating plate 104a and the rack gear 120b fixed to the sheet width regulating plate 104b. For this reason, the sheet width regulating plates 104a and 104b shown in FIG. 3 move symmetrically within the range in which the pinion gear boss 133 is guided by the guide groove 123m.

  When the cassette 10 of variable sheet size type is assembled, the pinion gear 122 is inserted into the rotation shaft 123j so that the pinion gear boss 133 is held in the guide groove 123m. As a result, the pinion gear 122 can rotate within the angular range in which the guide groove 123m is formed around the rotation shaft 123j. Since the movement range of the sheet width regulating plates 104a and 104b when the sheet size is switched is within the rotation range of the pinion gear 122 limited to the guide groove 123m, the sheet 10 of variable sheet size type can be assembled. .

  In the assembly state of the fixed sheet size type shown in FIG. 8B, the pinion gear 122 is attached at a position rotated 180 degrees from the assembly state of the variable sheet size type shown in FIG. At this time, the pinion gear boss 133 of the pinion gear 122 is inserted into the hole 123 h of the substrate 123. For this reason, the pinion gear 122 is restricted from rotating with respect to the substrate 123 because the pinion gear boss 133 is restrained by the hole 123 h of the substrate 123. Then, the pinion gear 122 whose rotation is restricted meshes with the rack gear 120a fixed to the sheet width restriction plate 104a and the rack gear 120b fixed to the sheet width restriction plate 104b, so that the sheet width restriction plates 104a and 104b are engaged. The rotation is restricted.

  When assembling the cassette 10 having a fixed sheet size, the pinion gear 122 is inserted into the rotating shaft 123j with the pinion gear boss 133 held loosely in the hole 123h. Accordingly, the rotation of the pinion gear 122 is locked on the substrate 123 while securing a backlash amount corresponding to the difference in diameter between the pinion gear boss 133 and the hole 123h. The sheet width regulating plates 104a and 104b are locked to move in the sheet width direction on the substrate 123 while securing a room for movement in the sheet width direction corresponding to the amount of play of the pinion gear 122 on the substrate 123. As a result, it is possible to assemble the sheet size fixed type cassette 10 in which a certain amount of play is set on the sheet width regulating plates 104a and 104b.

(Effect of Embodiment 2)
In the second embodiment, similar to the first embodiment, the sheet size variable type cassette 10 and the component parts are shared, and the sheet size fixed type cassette 10 with less difference in sheet feeding performance and less variation is manufactured. be able to. Further, the sheet size variable type cassette 10 can be easily reassembled into the sheet size fixed type cassette 10 without adding or changing components.

<Other embodiments>
The sheet stacking apparatus of the present invention is not limited to the specific configuration and control described in the first and second embodiments. For example, in the first and second embodiments, the pinion gear boss is used when assembling the fixed sheet size type cassette 10. However, the present invention is not limited to this, and a boss that can freely protrude from the substrate 123 toward the pinion gear hole may be provided. When assembling the cassette 10 of the fixed sheet size type, it is only necessary to engage the pinion gear by protruding the retracted boss and fix the rotation of the pinion gear. The image forming apparatus is not limited to a monochrome printer, and may be a full color printer. The present invention can also be implemented in embodiments such as a multi-function printer, a single-function printer, a copying machine, a facsimile machine, and a multifunction machine that combines these functions. Even in an image forming apparatus based on another operation principle such as an ink jet method, or an apparatus that handles sheets for application purposes other than image formation, the sheet stacking apparatus of the present invention is implemented, so that the same as in the first and second embodiments An effect can be obtained.

  In the first and second embodiments, the embodiment of the cassette 10 as a sheet stacking apparatus has been described. However, the sheet stacking apparatus is implemented as a multi-feed unit, a manual feed unit, and a document feed unit of an image reading apparatus. May be.

1: image forming apparatus, 2: sheet feeding unit, 3: image forming unit, 5: interlocking mechanism, 10: cassette (sheet stacking apparatus), 101: half moon feeding roller, 102: stacking plate, 103: compression spring, 104a 104b: sheet width regulating plate (regulating means), 105a, 105b: separation claw, 119: width regulating plate hole, 120a, 120b: rack gear, 121a, 121b: position holding unit, 122: pinion gear (setting means), 123 : Substrate, 123a, 123h: hole (engagement portion), 123j: rotating shaft, 123m: guide groove (avoidance portion), 124a, 124b: positioning groove, 125a, 125b: positioning groove, 126: gear shape, 127: patchon Claw, 128: Bottom plate (loading portion), 131, 133: Pinion gear boss (setting means, engaging means)

Claims (6)

A stacking unit on which sheets are stacked;
A pair of regulating means for regulating the stacking position of the sheets stacked on the stacking unit;
A sheet stack comprising: a first state capable of selecting a restriction position by the pair of restriction means; and a setting means capable of setting a second state in which the selection by the pair of restriction means is impossible. apparatus. The setting means includes
A pinion gear meshing with a first rack gear provided on one of the pair of regulating means and a second rack gear provided on the other of the pair of regulating means;
The sheet stacking apparatus according to claim 1, further comprising an engaging unit that can fix the pinion gear by engaging with the stacking unit.   3. The sheet stacking apparatus according to claim 2, wherein the setting unit sets the second state by engaging the engaging unit with the stacking unit.   4. The sheet stacking apparatus according to claim 2, wherein the pinion gear is disposed on both sides of the setting unit, and the engagement unit is disposed on one side. 5. The pinion gear and the engaging means are arranged on the same surface of the setting means,
The stacking portion includes an avoidance portion that avoids engagement with the engagement means so as to set the first state, and an engagement portion that engages with the engagement means so as to set the second state. The sheet stacking apparatus according to claim 2, wherein the sheet stacking apparatus includes: A sheet stacking apparatus according to any one of claims 1 to 5,
An image forming apparatus comprising: an image forming unit that forms an image on a sheet fed from the sheet stacking device.

Images