Sheet feeding device and image forming device

Abstract

To provide a sheet feeding device which has a simple structure, and in which a setting property is favorable when inserting a feeding cassette into a device body.SOLUTION: A feeding cassette 40 is provided which can be inserted into / pulled out of an image forming device body 1 (device body). Then, in the feeding cassette 40, an engagement pin 45 is provided protruding in a protrusion direction (-X direction) orthogonal to an insertion direction (-Y direction) with respect to the image forming device body 1. On the other hand, in the image forming device body 1, a guide part 71 which guides the engagement pin 45 when inserting the feeding cassette 40 is formed so as to extend in the insertion direction (±Y direction), and a pull-in mechanism 72 is provided which pulls in the engagement pin 45 toward a predetermined position in the insertion direction (-Y direction), in the guide part 71 in a state where the engagement pin 45 is engaged. Then, the engagement pin 45 is held at the feeding cassette 40 in a non-fixed manner so as to move with respect to an orthogonal direction (±Z direction) orthogonal to the insertion direction (-Y direction) and the protrusion direction (-X direction).SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a sheet feeding device that feeds sheets such as paper, and an image forming apparatus including the sheet feeding device, such as a copying machine, a printer, a facsimile machine, or a multifunction machine or a printing machine that includes the sheet feeding device. [Background technology]

[0002] Conventionally, in sheet feeding devices installed in image forming apparatuses such as copiers, printers, and printing machines, a technology has been widely known in which a retraction mechanism is used to retract the feed cassette in the insertion direction while inserting it in order to improve the ease of insertion of a removably insertable feed cassette into the image forming apparatus main body (see, for example, Patent Document 1).

[0003] In detail, in the sheet feeding device in Patent Document 1, an engagement pin is installed on a sheet cassette (feed cassette) via a holding arm, and an arc-shaped guide groove for guiding the engagement pin and a toggle arm that rotates in an engaged state with the engagement pin are installed on the device body. Then, while the toggle arm engaged with the engagement pin rotates so that the engagement pin installed on the holding arm is guided by the guide groove, the sheet cassette is pulled into the back side of the device body, and the setting of the sheet cassette in the device body is completed. Summary of the Invention [Problem to be solved by the invention]

[0004] In the sheet feeding device of Patent Document 1, the engagement pin is held via a holding arm, and therefore the number of parts is large and the configuration is complicated, resulting in high costs and large size of the device. In addition, when the engagement pin moves in the insertion direction while being guided by the guide portion (guide groove), the resistance when the engagement pin slides on the guide portion increases, resulting in poor setting properties.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide a sheet feeding device and an image forming apparatus that have a simple configuration and excellent set-up properties when inserting a feeding cassette into the device main body. [Means for solving the problem]

[0006] The sheet feeding device of this invention comprises a feeding cassette that is insertable and removable from the device main body, the feeding cassette having an engagement pin that protrudes in a protruding direction perpendicular to the insertion direction into the device main body, the device main body being formed to extend in the insertion direction and comprising a guide portion that guides the engagement pin when the feeding cassette is inserted, and a retraction mechanism that retracts the engagement pin in the insertion direction toward a predetermined position in the guide portion when the engagement pin is engaged, and the engagement pin is held loosely in the feeding cassette so as to be able to move freely in a perpendicular direction perpendicular to the insertion direction and the protruding direction. Effect of the Invention

[0007] According to the present invention, it is possible to provide a sheet feeding device and an image forming apparatus which are simple in configuration and in which the ease of setting when inserting a feeding cassette into the apparatus main body is excellent. [Brief description of the drawings]

[0008] [Figure 1] 1 is an overall configuration diagram showing an image forming apparatus according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a schematic diagram illustrating a sheet feeding device. [Diagram 3] FIG. 4 is a perspective view showing a part of a feeding cassette. [Figure 4] 5 is a partial perspective view showing an operation of inserting a feeding cassette into a drawing device of an apparatus main body in a sheet feeding apparatus; FIG. [Diagram 5] FIG. [Figure 6] FIG. 13 is a top view showing a protruding portion of the feeding cassette. [Figure 7]11 is a schematic diagram showing a backlash between an engagement pin and a hole. FIG. [Figure 8] 11A and 11B are diagrams illustrating the operation of a retraction mechanism. [Figure 9] 13A and 13B are diagrams illustrating a trajectory of an engagement pin guided by a guide portion. [Figure 10] 11A and 11B are cross-sectional views showing the operation of an engagement pin in a hole when guided by a guide portion. [Figure 11] 5 is a schematic diagram showing a dimensional relationship between an engagement pin in a feeding cassette and a guide portion in an apparatus main body. FIG. [Figure 12] FIG. 13 is a perspective view showing an engagement pin as a modified example. [Figure 13] 13 is a cross-sectional view showing a main part of a feeding cassette in which the engagement pin of FIG. 12 is installed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and the duplicated description will be appropriately simplified or omitted.

[0010] First, the overall configuration and operation of an image forming apparatus 1 will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes a copier as an image forming apparatus, reference numeral 2 denotes an original reading section that optically reads image information from an original D, reference numeral 3 denotes an exposure section that irradiates a photosensitive drum 5 with exposure light L based on the image information read by the original reading section 2, reference numeral 4 denotes an image creating section that forms a toner image (image) on the photosensitive drum 5, and reference numeral 7 denotes a transfer section (image forming section) that transfers the toner image formed on the photosensitive drum 5 to a sheet P. Also, reference numeral 10 denotes a document transport section (automatic document transport device) that transports the set document D to the document reading section 2, 12 and 13 denote sheet feeding devices that feed sheets P stored in the feeding cassette 40, and 16 denotes a manual sheet feeding device that feeds sheets P that have been manually set by the user. In addition, reference numeral 17 denotes a pair of registration rollers (pair of transport rollers) that transport the sheet P toward the transfer section 7, 20 denotes a fixing device that fixes the toner image (unfixed image) carried on the sheet P, 21 denotes a fixing roller installed in the fixing device 20, 22 denotes a pressure roller installed in the fixing device 20, and 31 denotes an output tray on which the sheet P discharged from the device main body 1 is stacked. Further, 40 and 40' denote feeding cassettes installed in the sheet feeding devices 12 and 13, respectively, and 52 denotes a feeding mechanism installed in the sheet feeding devices 12, 13, and 16, respectively.

[0011] With reference to FIG. 1, the operation of the image forming apparatus main body 1 during normal image formation will be described. First, the document D is transported (fed) from the document table in the direction of the arrow in the figure by the transport rollers of the document transport unit 10, and passes over the document reading unit 2. At this time, the document reading unit 2 optically reads image information of the document D passing above it. The optical image information read by the document reading unit 2 is converted into an electrical signal and then transmitted to the exposure unit 3 (writing unit). The exposure unit 3 then emits exposure light L, such as a laser beam, based on the image information of the electrical signal toward the photoconductor drum 5 of the imaging unit 4.

[0012] Meanwhile, in the image creating unit 4, the photosensitive drum 5 rotates clockwise in FIG. 1, and after going through a predetermined image creating process (charging process, exposure process, and development process), an image (toner image) corresponding to the image information is formed on the photosensitive drum 5. Thereafter, the image formed on the photosensitive drum 5 is transferred onto a sheet P conveyed by a pair of registration rollers 17 in a transfer section 7 serving as an image forming section.

[0013] On the other hand, the sheet P conveyed to the transfer unit 7 (image forming unit) operates as follows. First, one of the multiple sheet feeding devices 12, 13 of the image forming apparatus main body 1 is automatically or manually selected (for example, it is assumed that the lower sheet feeding device 13 is selected). Then, the uppermost sheet of sheets P such as paper stored in the feeding cassette 40 of the sheet feeding device 13 is fed by the feeding mechanism 52 and conveyed toward the conveying path K. Thereafter, the sheet P passes through the conveying path K on which multiple conveying rollers are arranged, and reaches the position of the registration roller pair 17. When the sheet feeding device 16 (manual sheet feeding device) installed on the side of the device main body 1 is selected, the sheet P placed by the user on the manual feed tray of the sheet feeding device 16 (the uppermost sheet P when multiple sheets P are stacked) is fed by the feeding mechanism 52 toward the conveying path and reaches the position of the registration roller pair 17.

[0014] Then, the pair of registration rollers 17 start to rotate, and the sheet P, after having had its skew corrected by the pair of registration rollers 17, is transported toward the transfer section 7 (image forming section) in a timed manner to align it with the image formed on the photosensitive drum 5.

[0015] After the transfer process, the sheet P passes through the position of the transfer unit 7, and then reaches the fixing device 20 via a transport path. The sheet P that has reached the fixing device 20 is fed between the fixing roller 21 and the pressure roller 22, and the toner image is fixed onto the sheet P by the heat received from the fixing roller 21 and the pressure received from both members 21 and 22 (the fixing process). The sheet P after the fixing process with the toner image fixed onto it is sent out from between the fixing roller 21 and the pressure roller 22 (the fixing nip), and then discharged from the image forming apparatus main body 1 and stacked on the paper output tray 31 as an output image. In this way, a series of image forming processes is completed.

[0016] Next, the sheet feeding device according to the present embodiment will be described with reference to FIG. Of the multiple sheet feeding devices 12, 13 installed inside the device main body 1, only the lower sheet feeding device 13 will be described below. However, the upper sheet feeding device 12 has a configuration similar to that of the lower sheet feeding device 13 except for its installation position, so its description will be omitted.

[0017] Referring to FIG. 2, the sheet feeding device 13 is mainly composed of a feeding cassette 40 configured to be capable of stacking multiple sheets (or one sheet) P, and a sheet feeding device main body (in this embodiment, formed integrally with the image forming device main body 1) in which a feeding mechanism 52 for feeding the sheets P stacked in the feeding cassette 40 and the like are installed. The feeding cassette 40 is composed of a bottom plate 42 that can be raised and lowered, a side fence 46 that can move in the width direction, an end fence 47 that can move in the feeding direction, and the like, the details of which will be described later with reference to FIG.

[0018] As shown in FIG. 2, the feeding mechanism 52 is made up of a feed roller 53, a pickup roller 54, a separation roller 55, and the like. The feed roller 53 is installed at the leading end side in the feeding direction (the direction of the white arrow in Figure 2, which is the transport direction) of the sheets P stacked on the bottom plate 42 and base portion 41 (loading portion) of the feed cassette 40, and contacts the upper surface of the sheets P and rotates along the feeding direction of the sheets P (counterclockwise rotation in Figure 2) to feed the sheets P in the feeding direction (+X direction) indicated by the dashed dotted arrow.

[0019] The pickup roller 54 rotates counterclockwise in FIG. 2 along the running direction while in contact with the surface (top) of the sheet P stacked in the feeding cassette 40, thereby transporting the sheet P toward the position of the feed roller 53. A timing belt 59 is stretched and supported between a pulley installed on the pickup roller 54 and a pulley installed on the feed roller 53. Driving force is transmitted from the feed motor through a gear train, the feed roller 53, and the timing belt 59 to the pickup roller 54, so that the pickup roller 54 is driven to rotate in the counterclockwise direction in FIG.

[0020] The pickup roller 54 is configured to be capable of contacting and separating from the sheet P (the uppermost sheet P) stacked in the feeding cassette 40. That is, the pickup roller 54 is formed to be capable of moving between a retracted position where it does not contact the sheet P stacked in the feeding cassette 40 and a contact position where it contacts the sheet P. More specifically, the pickup roller 54 is rotatably held by an arm 58. The arm 58 is rotatably held by the shaft portion of the feed roller 53. A spring that urges the pickup roller 54 to move to the retracted position, and a solenoid that moves the pickup roller 54 to the abutment position against the urging force of the spring are connected to the arm 58. Then, under the control of the control unit, when the solenoid is turned on, the pickup roller 54 moves to the abutment position as shown in FIG. 2, and when the solenoid is turned off, the pickup roller 54 moves to the retracted position. Incidentally, even when the pickup roller 54 is moving toward or away from the feed roller 53, the timing belt 59 is stretched and supported by the pulley of the pickup roller 54 and the pulley of the feed roller 53.

[0021] The separation roller 55 is disposed so as to form a nip portion between itself and the feed roller 53 . When a sheet P is sandwiched in the nip portion and when no sheet P is sandwiched in the nip portion, the separation roller 55 rotates in the forward direction (the direction of the dashed arrow in Figure 2, which is a clockwise direction) along the feeding direction. In contrast, when multiple sheets are sandwiched in the nip portion, separation roller 55 rotates in the opposite direction to the forward direction described above (the direction of the solid arrow in FIG. 2, which is counterclockwise). As a result, the uppermost sheet P of the multiple sheets P sandwiched in the nip portion is fed in the feeding direction along with the rotation of feed roller 53, and the lower sheet P is transported in the opposite direction to the feeding direction (forward direction), thereby preventing double feeding of sheets P.

[0022] Here, in the sheet feeding device 13 in the present embodiment, the bottom plate 42 is raised and lowered in the vertical direction depending on the number of sheets P stacked on the bottom plate 42 so that the pickup roller 54 can abut against the uppermost sheet P stacked in the feeding cassette 40. Then, the pickup roller 54 is lowered to a position where it abuts against the upper surface of the sheet P placed on the bottom plate 42 whose vertical position has been adjusted, and then the sheet P is fed. In addition, an entrance guide plate is provided between the feeding cassette 40 and the nip portion between the feed roller 53 and the separation roller 55 .

[0023] In the sheet feeding device 13 configured as above, when no sheet P is set in the feeding cassette 40, this state is detected by an end detection sensor installed at the bottom. At this time, the bottom plate 42 is in a state where it is lowered to the lowest set position far away from the pickup roller 54 (a position where the sheet P can be set). When a sheet P is set in the feeding cassette 40, the state is detected by an end detection sensor, and the control unit controls the motor to raise the bottom plate 42 to a position where the uppermost sheet P of the set sheet contacts the pickup roller 54 (the position shown in Figure 2). 2, the pickup roller 54 starts rotating counterclockwise with the pickup roller 54 in contact with the upper surface of the uppermost sheet P placed on the bottom plate 42, and at the same time, the feed roller 53 and the separation roller 55 start rotating. As a result, the pickup roller 54 transports the uppermost sheet P of the sheet stack placed on the feeding cassette 40 toward the nip portion between the feed roller 53 and the separation roller 55, and one sheet P is separated from the nip portion and transported toward the image forming unit. Furthermore, when all the sheets P placed on the feeding cassette 40 have been fed and no sheets P are set in the feeding cassette 40, this state is detected by the end detection sensor, and the bottom plate 42 is again lowered to the set position by the motor control by the control unit.

[0024] In this embodiment, the sheet feeding device 13 is mainly composed of a sheet feeding device main body as the device main body (in this embodiment, it is formed integrally with the image forming device main body 1) and a feeding cassette 40 capable of loading multiple sheets P.

[0025] As shown in FIG. 3, the feeding cassette 40 is a substantially rectangular box-shaped member, and inside thereof, a pair of side fences 46, an end fence 47, a bottom plate 42 (see FIG. 2), and the like are provided on a base portion 41. An exterior cover 43 is provided on one of the four sides of the feed cassette 40 in the +Y direction. A handle 43a is provided on the exterior cover 43, and the user inserts and removes the feed cassette 40 in the ±Y direction relative to the image forming apparatus main body 1 (apparatus main body) while holding the handle 43a. In detail, when the feed cassette 40 is pulled out in the +Y direction (removal direction, pull-out direction) relative to the image forming apparatus main body 1, the sheets P are loaded in the feed cassette 40, and then the feed cassette 40 is mounted in the image forming apparatus main body 1 in the -Y direction (insertion direction, mounting direction). Such an inserting and removing operation (mounting and removing operation) is performed every time the sheets P are set (refilled) in the feed cassette 40.

[0026] Here, in the feeding cassette 40, a pair of side fences 46 and one end fence 47 are installed to surround the space (space in which sheets P are stacked) above (in the ±Z direction) where the base portion 41 and bottom plate 42 (see Figure 2) are installed, on three sides except for the downstream side in the feeding direction (in the +X direction).

[0027] The side fences 46 function as sheet regulating members that regulate the position in the width direction (±Y direction) of the sheet P placed on the feeding cassette 40. The side fences 46 are installed at both ends in the width direction so as to sandwich the sheet P, and are configured to be movable in the width direction in accordance with the width size of the sheet P. The side fences 46 are manually moved in the width direction along the guide rails to determine the posture of the sheet P in the width direction within the feeding cassette 40. This allows the sheet P, whose position in the width direction has been determined, to be smoothly fed from the feeding cassette 40. In this embodiment, the pair of side fences 46 are configured to increase or decrease the widthwise distance in cooperation with each other. That is, when one side fence 46 is manually moved in the +Y direction, the other side fence 46 moves in the -Y direction in cooperation with each other, and when one side fence 46 is manually moved in the -Y direction, the other side fence 46 moves in the +Y direction in cooperation with each other. As a moving mechanism for interlocking the pair of side fences 46, a pinion-rack mechanism can be used that includes a rack gear portion integrally formed so as to extend in the width direction perpendicular to one side fence 46, a rack gear portion integrally formed so as to extend in the width direction perpendicular to the other side fence 46, and a pinion gear that is sandwiched between and meshed with both rack gear portions.

[0028] The end fence 47 functions as a sheet regulating member that regulates the position of the upstream side in the feeding direction (the rear end side of the sheet in the -X direction) of the sheet P placed on the feeding cassette 40. The end fence 47 is installed so as to come into contact with the rear end of the sheet P in the feeding direction, and is configured to be movable in the feeding direction in accordance with the size of the sheet P in the feeding direction. The end fence 47 is manually moved in the width direction along the guide rail to determine the orientation of the sheet P in the feeding direction in the feeding cassette 40. This allows the sheet P, whose position in the feeding direction has been determined, to be smoothly fed from the feeding cassette 40.

[0029] Hereinafter, the characteristic configuration and operation of the sheet feeding device 13 (image forming apparatus 1) in the present embodiment will be described with reference to FIGS. 3 to 11 and so on. As described above with reference to FIG. 3 and the like, the sheet feeding device 13 in this embodiment is provided with a feeding cassette 40 that is insertable into and detachable from the image forming apparatus main body 1 serving as the apparatus main body.

[0030] Now, referring to Figures 3(B), 4(A), 6, etc., the feeding cassette 40 in this embodiment is provided with an engagement pin 45 that protrudes in a protruding direction (-X direction) perpendicular to the insertion direction (-Y direction) into the image forming apparatus main body 1 (apparatus main body). In detail, as shown in Figures 3, 4, etc., the feeding cassette 40 is provided with a protrusion 44 that protrudes in the insertion direction (-Y direction) at the end downstream of the insertion direction (-Y direction) and in the protruding direction (width direction, -X direction).

[0031] More specifically, the protrusion 44 is a portion formed so as to extend in the -Y direction at the widthwise end of a box-shaped portion (containing the base portion 41, side fences 46, end fences 47, bottom plate 42, etc.) surrounded on all four sides of the feeding cassette 40. The feeding cassette 40 is inserted into and removed from the image forming apparatus main body 1 while the widthwise end portion including the protrusion 44 slides on a rail portion formed in the image forming apparatus main body 1. In this embodiment, the engagement pin 45 is formed to protrude horizontally toward the center in the width direction (-X direction) in the protruding portion 44. When the feeding cassette 40 is inserted (attached) into the image forming apparatus main body 1, the engagement pin 45 is retracted by a retracting unit 70 (see FIGS. 4, 8, etc.) described later, and then positioned at a predetermined position (positioning position), which will be described in detail later with reference to FIGS. 8, 9, etc. In addition, in this embodiment, the engagement pin 45 is not fixedly held to the protrusion 44 of the feed cassette 40, but is held in an unfixed manner so as to be able to move freely on the protrusion 44 of the feed cassette 40, which will be described in detail later using Figures 6, 7, 9 to 11, etc.

[0032] Incidentally, with reference to FIG. 4 and other figures, the protruding portion 44 in this embodiment is provided with rollers 49 for smoothly inserting and removing the feeding cassette 40 into and from the image forming apparatus main body 1 (rail portion). Although not shown, the front surface of the feeding cassette 40 (the side on which the exterior cover 43 is installed) is provided with a positioning pin that can fit into a positioning hole formed in the housing of the image forming apparatus main body 1. In addition to the protrusion 44 on one widthwise end where the engagement pin 45 is installed, the feeding cassette 40 also has a protrusion on the other widthwise end that protrudes in the insertion direction, and the portion on the other widthwise end including this protrusion slides along a rail portion formed on the image forming device main body 1, allowing the feeding cassette 40 to be inserted and removed from the image forming device main body 1 in a balanced manner.

[0033] On the other hand, referring to FIGS. 4, 8, 9, etc., the image forming apparatus main body 1 as the apparatus main body is provided with a guide portion 71, a retraction mechanism 72 (73 to 78), a damper 79, etc. The guide portion 71 is a groove portion that guides the engagement pin 45 when the feeding cassette 40 is inserted into the image forming apparatus main body 1, and is formed to extend in the insertion direction (±Y direction). The guide portion 71 (groove portion) is configured so that the groove width direction is the up-down direction (the orthogonal direction perpendicular to the insertion direction and the protruding direction, which is the ±Z direction). The retraction mechanism 72 is a mechanism for retracting the engagement pin 45 in the insertion direction (-Y direction) toward a predetermined position (the position shown by the solid line in Figure 9, which is the positioning position) in the guide portion 71 when the engagement pin 45 is engaged. The damper 79 is a member for cushioning the impact when the feeding cassette 40 comes into contact with the drawing unit 70 during insertion of the feeding cassette 40 .

[0034] In detail, referring to FIG. 8 etc., a substantially rectangular parallelepiped retraction unit 70 is fixed to a main body side plate (not shown) on the downstream side in the insertion direction of the image forming apparatus main body 1 (rear side in the mounting direction). The retraction unit 70 has a guide portion 71 formed on one side surface (a side surface on one end side in the width direction, which is an opposing surface facing the engagement pin 45 of the protrusion 44), and a retraction mechanism 72 is provided inside (a side surface on the center side in the width direction). The guide portion 71 communicates with the inside of the retraction unit 70, and is configured so that the engagement pin 45 inserted into the guide portion 71 engages with an engagement groove 73b of a first arm member 73, which will be described later. The retraction mechanism 72 is made up of first and second arm members 73, 74 as arm members, first and second tension springs 75, 76 as biasing members, gears 77, 78, and the like. An engagement groove 73b with which engagement pin 45 is freely engaged is formed in the arm member (first arm member 73), and the arm member is configured to be rotatable about a fulcrum (axis 73a) spaced apart from the guide portion 71. The first and second tension springs 75, 76 function as biasing members that bias the arm members 73, 74 so that the engagement pin 45 engaged with the engagement groove 73b is pulled in the insertion direction (-Y direction).

[0035] More specifically, the first arm member 73 is installed so as to be rotatable about a support shaft 73a serving as a fulcrum. A gear portion 73c (meshing with a gear train 77, 78 installed in the retracting unit 70) is formed at the base of the first arm member 73 and is centered on the support shaft 73a, and an engagement groove 73b (the engagement pin 45 is formed in a notch shape so as to be swingable) with which the engagement pin 45 can be engaged, and a hook portion that can be fitted into the lock pin 70x (installed on the side surface of the retracting unit 70) are formed at the tip. The second arm member 74 is installed so as to be rotatable about a support shaft 74a. One end of a first tension spring 75 is connected to one end of the second arm member 74. The other end of the first tension spring 75 is connected to the first arm member 73. One end of a second tension spring 76 is connected to the other end of the second arm member 74. The other end of the second tension spring 76 is connected to the housing of the retraction unit 70.

[0036] In the retraction mechanism 72 configured as above, when the feeding cassette 40 is pulled out from the image forming apparatus main body 1, as shown in Figures 8(A1) and (A2), the first arm member 73 is locked by the lock pin 70x, and the engagement groove 73b of the first arm member 73 is in a standby state on the upstream side (left side in Figure 8) in the insertion direction of the guide portion 71. At this time, a biasing force in the retraction direction by the first and second tension springs 75, 76 is applied to the first arm member 73 via the second arm member 74, but the standby state shown in Figure 8(B2) is maintained by the locking force of the first arm member 73 by the lock pin 70x and the load resistance via the gear trains 77, 78. Then, when the feeding cassette 40 is inserted into the image forming apparatus main body 1 and the engagement pin 45 of the feeding cassette 40 (projection 44) engages with the engagement groove 73b of the first arm member 73, the locking state by the lock pin 70x of the first arm member 73 is released by the pressing force at that time. As a result, the engagement pin 45 (feeding cassette 40) is pulled to the right side (-Y direction) of Fig. 8 by the first arm member 73 with the engagement pin 45 engaged with the engagement groove 73b due to the urging force in the pulling direction by the first and second tension springs 75, 76 via the second arm member 74. At this time, the engagement pin 45 moves in the insertion direction (-Y direction) in the guide portion 71 from the left side to the right side of Fig. 8, as shown by the dashed line in Fig. 9. Finally, when the retraction mechanism 72 assumes the posture shown in Figures 8 (B1) and (B2), the engagement pin 45 reaches a predetermined position (the desired position shown by the solid line in Figure 9), and the feed cassette 40 abuts against the main body side panel at the rear side in the insertion direction of the image forming apparatus main body 1, thereby determining the set position of the feed cassette 40 in the image forming apparatus main body 1. When the feeding cassette 40 is pulled out from the image forming apparatus main body 1, the above-mentioned operations for insertion are performed in reverse.

[0037] Now, referring to Figure 10 etc., in this embodiment, the engagement pin 45 is held loosely to the feed cassette 40 (protrusion 44) so ​​as to be movable (in a state in which it can move freely) in the perpendicular direction (in this embodiment, the up and down direction (±Z direction)) perpendicular to the insertion direction (the insertion direction of the feed cassette 40, which is the -Y direction) and the protrusion direction (the direction in which the engagement pin 45 protrudes, which is the -X direction). That is, the engagement pin 45 is not fixedly held by the feeding cassette 40 (the protruding portion 44), but is held loosely so that its position is not fixed.

[0038] In detail, referring to FIGS. 5, 6, 10, etc., the feeding cassette 40 is formed with a hole 44a into which the large diameter portion 45b serving as an insertion portion of the engagement pin 45 is inserted. The feeding cassette 40 holds the engagement pin 45 so that it can tilt with respect to the protruding direction (±X direction) and can slide in the orthogonal direction (±Z direction) with a gap between the large diameter portion 45b (insertion portion) and the hole portion 44a in the ±Z direction (the orthogonal direction perpendicular to the insertion direction and the protruding direction). That is, the large diameter portion 45b (insertion portion) and the hole portion 44a are configured to have a backlash at least in the ±Z direction. Furthermore, the feeding cassette 40 holds the engagement pin 45 so that it can tilt with respect to the protruding direction (±X direction) and can slide in the insertion direction (±Y direction) with a gap between the large diameter portion 45b (insertion portion) and the hole portion 44a in the insertion direction (±Y direction). That is, the large diameter portion 45b (insertion portion) and the hole portion 44a are configured to generate a backlash in the ±Y direction. However, the hole 44a of the protrusion 44 is formed so that the gap (backlash) in the above-mentioned insertion direction (±Y direction) is smaller than the gap (backlash) in the above-mentioned orthogonal direction (±Z direction).

[0039] Specifically, as shown in FIG. 7, the hole 44a is an elliptical hole (or a long hole) whose longitudinal direction is the ±Z direction (orthogonal direction) and whose lateral direction is the ±Y direction (insertion direction). That is, when the hole diameter of the hole portion 44a in the longitudinal direction (±Z direction) is R2, the hole diameter of the hole portion 44a in the lateral direction (±Y direction) is R3, and the outer diameter of the large diameter portion 45b (insertion portion) of the engagement pin 45 is R1, R2-R1>R3-R1 A relationship like this will be established.

[0040] In this manner, in the sheet feeding device 13 of this embodiment, the engagement pin 45, which is retracted by the retraction mechanism 72 and guided to the guide portion 71, is directly and loosely held in the feeding cassette 40 (protrusion portion 44) so ​​as to be able to move freely with some play in at least the ±Z direction. Therefore, compared to a case where the engaging pin 45 is held on the feeding cassette 40 via a separate member such as a holding arm, the number of parts can be reduced and the configuration can be simplified. Therefore, the device is less likely to become expensive and large in size.

[0041] In addition, when the engagement pin 45 moves in the insertion direction (-Y direction) while being guided by the guide portion 71, the resistance when the engagement pin 45 slides against the guide portion 71 is less likely to become large, which improves the ease of setting the feeding cassette 40 into the image forming apparatus main body 1. In detail, in the retraction mechanism 72 of this embodiment, as previously described using Figure 8 etc., the first arm member 73 with which the engagement pin 45 engages rotates around a support shaft 73a spaced downward from the guide portion 71. That is, if the engagement pin 45 is held in a fixed state in the feed cassette 40, the retraction mechanism 72 is configured to retract the engaged engagement pin 45 while drawing an arc-shaped trajectory S (see FIG. 9) centered on a fulcrum (support shaft 73a) away from the guide portion 71. Therefore, if the engagement pin 45 is held in a fixed state in the feed cassette 40, even if the engagement pin 45 moves somewhat in the engagement groove 73b, a large sliding resistance is generated between the engagement pin 45 and the guide portion 71 in a certain area in the process in which the engagement pin 45 moves in the -Y direction in the guide portion 71, and the settling property of the feed cassette 40 becomes poor (the retraction load by the retraction mechanism 72 becomes large). In contrast, in this embodiment, the engagement pin 45 is not fixed to the feeding cassette 40 and is held freely movable with a backlash at least in the ±Z direction, so that even if a large sliding resistance is likely to occur between the engagement pin 45 and the guide portion 71 in a certain area during the process in which the engagement pin 45 moves in the -Y direction on the guide portion 71, the engagement pin 45 changes its position by tilting or sliding, thereby preventing the occurrence of such a large sliding resistance. This improves the ease of setting the feeding cassette 40 (reducing the retraction load by the retraction mechanism 72). Furthermore, by using a similar mechanism, when the feed cassette 40 is pulled out from the image forming apparatus main body 1, the sliding resistance between the engagement pin 45 and the guide portion 71 is reduced, thereby improving the pull-out ability (operability when pulling out) of the feed cassette 40.

[0042] Specifically, referring to Figures 9 and 10, during the process in which engagement pin 45 moves along guide portion 71 in the -Y direction, in range M1 of Figure 9, the tip side of engagement pin 45 inclines downward and left as shown in Figure 10(A), in range M2, the tip side of engagement pin 45 inclines upward and left as shown in Figure 10(B), and in range M3, the tip side of engagement pin 45 again inclines downward and left as shown in Figure 10(A).

[0043] As explained above, in this embodiment, in order to efficiently obtain the effect of reducing the sliding resistance between engagement pin 45 and guide portion 71, whose groove width direction is in the ±Z direction, the gap (R2-R1) between engagement pin 45 and hole portion 44a in the ±Z direction is set large. However, in order to further exert the effect of reducing the sliding resistance described above, a gap (R3-R1) in the ±Y directions between the engagement pin 45 and the hole 44a is also secured. However, if the gap in the ±Y directions is set large, the distance when the feeding cassette 40 is pulled into a predetermined position must be set large accordingly, which would result in an increase in the size of the device. For this reason, in this embodiment, the gap in the ±Y directions is set small compared to the gap in the ±Z directions.

[0044] Here, referring to Figure 5 etc., in this embodiment, engagement pin 45 is formed with a small diameter portion 45a guided by guide portion 71, and a large diameter portion 45b having an outer diameter larger than that of small diameter portion 45a and serving as an insertion portion to be inserted into hole portion 44a. A stop ring 50 is provided on the large diameter portion 45b as a restricting member for restricting movement of the engagement pin 45 in the protruding direction (-X direction). The stop ring 50 as a restricting member has an outer diameter larger than that of the large diameter portion 45b and is larger than the outer diameter (outer diameter R3 in the short side direction) of the hole portion 44a, and is provided in a circumferential groove portion 45b1 (see FIG. 10) formed in the large diameter portion 45b. The stop ring 50 is assembled so as to fit into the circumferential groove portion 45b1 from above the protruding portion 44 (which is an open space) after the engagement pin 45 without the stop ring 50 is inserted into the hole portion 44a from the left side in FIG. 6. With this configuration, even if an attempt is made to pull out the engagement pin 45 in the -X direction, the retaining ring 50 is caught on the edge (the inner wall surface 44c) around the hole 44a and the engagement pin 45 cannot be pulled out. This prevents the engagement pin 45 from falling off in the -X direction.

[0045] 6, 10, etc., the feeding cassette 40 (protruding portion 44) is formed with a limiting portion 44b that limits movement in the opposite direction (+X direction) to the protruding direction of the engaging pin 45. The limiting portion 44b is a wall portion formed inside (hollow portion) of the protruding portion 44, and is formed so that the engaging pin 45 (the end portion of the large diameter portion 45b) can come into contact with it. With this configuration, even if an attempt is made to push the engagement pin 45 in the +X direction, the large diameter portion 45b of the engagement pin 45 hits the limiting portion 44b, and the engagement pin 45 cannot be pushed in any further. This prevents the engagement pin 45 from being buried in the +X direction.

[0046] Referring to FIG. 11(A), in this embodiment, when the gap between engagement pin 45 (large diameter portion 45b) and hole portion 44a in the ±Z direction (orthogonal direction) is defined as C (=R2-R1), and the gap between engagement pin 45 (small diameter portion 45a (outer diameter is R1')) and guide portion 71 (groove width is Q) in the ±Z direction (orthogonal direction) is defined as D (=Q-R1'), D <C The system is structured so that a relationship like this can be established. With this configuration, it is possible to sufficiently ensure the freedom of movement in the ±Z directions of the engagement pin 45. Therefore, it becomes easier to achieve the effect of reducing the sliding resistance between the engagement pin 45 and the guide portion 71 whose groove width direction is the ±Z direction. In FIG. 11A, the shapes of the engagement pin 45, the protrusion 44, and the retraction unit 70 are simplified for ease of understanding.

[0047] Further, referring to FIG. 11A, in this embodiment, when the hole depth of the hole 44a is E and the distance from the inner wall surface 44c in which the hole 44a is formed in the feeding cassette 40 to the outer wall surface 70a (side surface) in which the guide portion 71 is formed in the pulling-out unit 70 (apparatus body 1) is F, D <C×F / E The system is structured so that a relationship like this can be established. 11(B), C×F / E in the above formula is the maximum amount by which the engagement pin 45 can be tilted (amount of deviation absorbed due to tilt) at the position of the guide portion 71 (outer wall surface 70a). Therefore, by satisfying the above formula, the play (amount of tilt) of the engagement pin 45 can be sufficiently ensured. Therefore, the effect of reducing the sliding resistance between the engagement pin 45 and the guide portion 71 can be more efficiently exerted without unnecessarily widening the gap C (backlash).

[0048] <Modification> As shown in FIGS. 12 and 13, in the modified engagement pin 45, a large diameter portion 45b (insertion portion) to be inserted into a hole portion 44a is formed in a drum shape. That is, the large diameter portion 45b (insertion portion) is formed in a curved shape such that the outer circumferential surface thereof bulges outward. With this configuration, when the engagement pin 45 is guided by the guide portion 71, the contact area of ​​the engagement pin 45 with the guide portion 71 can be reduced, which further reduces the sliding resistance between the engagement pin 45 and the guide portion 71. This further improves the setting property of the feeding cassette 40 (further reducing the retraction load of the retraction mechanism 72).

[0049] As described above, the sheet feeding device 13 in this embodiment is provided with the feeding cassette 40 which is insertable into and removable from the image forming apparatus main body 1 (apparatus main body). The feeding cassette 40 is provided with the engagement pin 45 which protrudes in a protruding direction (-X direction) perpendicular to the insertion direction (-Y direction) into the image forming apparatus main body 1. On the other hand, the image forming apparatus main body 1 is provided with a guide portion 71 which guides the engagement pin 45 when the feeding cassette 40 is inserted, and which extends in the insertion direction (±Y direction), and a retraction mechanism 72 which retracts the engagement pin 45 in the insertion direction (-Y direction) toward a predetermined position in the guide portion 71 in a state where the engagement pin 45 is engaged. The engagement pin 45 is held in a non-fixed manner by the feeding cassette 40 so as to be movable in an orthogonal direction (±Z direction) perpendicular to the insertion direction (-Y direction) and the protruding direction (-X direction). This simplifies the configuration and facilitates the insertion of the feeding cassette 40 into the apparatus main body 1 .

[0050] In this embodiment, the present invention is applied to sheet feeding device 13 installed on the lower level inside image forming apparatus 1, but the present invention can naturally also be applied to sheet feeding device 12 installed on the upper level inside image forming apparatus 1. In addition, in this embodiment, the present invention is applied to sheet feeding devices 12, 13 installed in a monochrome image forming apparatus 1, but the present invention can naturally also be applied to a sheet feeding device installed in a color image forming apparatus. In addition, in this embodiment, the present invention is applied to the sheet feeding devices 12 and 13 built into the image forming apparatus 1, but the present invention can also be applied to a sheet feeding device (such as a large-capacity paper feed bank) that is externally attached to the image forming apparatus 1. In that case, in the sheet feeding device, the device main body (sheet feeding device main body) into and out of which the feeding cassette is inserted is provided separately from the image forming apparatus main body. Furthermore, in this embodiment, the present invention is applied to sheet feeding devices 12, 13 installed in an electrophotographic image forming apparatus 1, but the application of the present invention is not limited to this, and the present invention can also be applied to sheet feeding devices installed in other types of image forming apparatuses (for example, inkjet image forming apparatuses, stencil printers, etc.). In addition, the feeding mechanism 52 of the sheet feeding device 13 in this embodiment is not limited to the FRR type using the feed roller 53, the pickup roller 54, and the separation roller 55, but various types such as the pad type can be used. Even in such cases, the same effects as those of this embodiment can be obtained.

[0051] In addition, in this embodiment, of the protrusions formed on both ends of the feed cassette 40 in the width direction, an engagement pin 45 is provided only on the protrusion 44 at one width end, and one corresponding retraction unit 70 is installed in the image forming apparatus main body 1, but it is also possible to provide an engagement pin on the protrusion at the other width end, and to provide another corresponding retraction unit in the image forming apparatus main body 1. In the present embodiment, the device body 1 is configured such that the engagement pin 45 in the feeding cassette 40 protrudes in the horizontal direction, and the groove width direction (orthogonal direction) of the guide portion 71 with which the engagement pin 45 engages is the up-down direction. However, the protruding direction of the engagement pin and the groove width direction (orthogonal direction) of the guide portion are not limited to this, and for example, the device body can be configured such that the engagement pin in the feeding cassette protrudes in the vertical direction, and the groove width direction (orthogonal direction) of the guide portion with which the engagement pin engages is the horizontal direction. In the present embodiment, the hole 44a into which the engagement pin 45 is inserted is formed in an elliptical shape, but the hole 44a may be formed in a perfect circle. In that case, the hole diameter of the hole 44a is set to be larger than the outer diameter of the large diameter portion 45b (insertion portion) of the engagement pin 45. Even in such cases, the same effects as those of this embodiment can be obtained.

[0052] It is clear that the present invention is not limited to the present embodiment, and that the present embodiment may be modified as appropriate within the scope of the technical concept of the present invention in addition to the modifications suggested in the present embodiment. Furthermore, the number, position, shape, etc. of the components are not limited to the present embodiment, and may be any number, position, shape, etc. suitable for implementing the present invention.

[0053] In this specification, the term "sheet" is defined to include not only ordinary paper, but also all sheet-like recording media (including manuscripts), such as coated paper, label paper, OHP sheets, and film. [Explanation of symbols]

[0054] 1 Image forming apparatus (image forming apparatus main body, apparatus main body), 13 sheet feeding device, 40 Feeding cassette (sheet stacking device), 44 protrusion, 44a hole, 44b Restriction section, 44c Inner wall surface, 45 engagement pin, 45a Small diameter part (tip part), 45b large diameter portion (insertion portion), 45b1 Circumferential groove, 50 retaining ring (regulating member), 70 retraction units, 70a Exterior wall surface, 71 Guide part, 72 Retraction mechanism, 73 first arm member (arm member), 73a Support shaft (fulcrum), 73b Engagement groove, 73c gear part, 74 second arm member (arm member), 74a Support shaft (fulcrum), 75 First tension spring (biasing member), 76 second tension spring (biasing member), 77, 78 Gear, 79 Damper, P-sheet.

[0055] The present invention can also be embodied in the following combinations of Supplementary Notes 1 to 13. (Appendix 1) A feeding cassette is provided which is insertable into and removable from the main body of the device, the feeding cassette is provided with an engagement pin that protrudes in a protruding direction perpendicular to a direction of insertion into the apparatus body, The device body includes: a guide portion extending in the insertion direction and configured to guide the engagement pin when the feeding cassette is inserted; a retraction mechanism that retracts the engagement pin in the insertion direction toward a predetermined position in the guide portion while the engagement pin is engaged; Equipped with The sheet feeding device according to claim 1, wherein the engagement pin is held in the feeding cassette in a non-fixed manner and movable in a direction perpendicular to the insertion direction and the protruding direction. (Appendix 2) The feeding cassette includes: A hole into which the insertion portion of the engagement pin is inserted is formed, The sheet feeding device described in Appendix 1, characterized in that the engagement pin is held so as to be inclined with respect to the protruding direction and so as to be slidable in the perpendicular direction while there is a gap between the insertion portion and the hole portion in the perpendicular direction. (Appendix 3) The sheet feeding device described in Appendix 2, characterized in that the feeding cassette holds the engagement pin so that it can be tilted with respect to the protrusion direction and can slide in the insertion direction with a gap between the hole portion and the insertion portion in the insertion direction. (Appendix 4) The sheet feeding device according to claim 2 or 3, wherein the hole is formed so that a gap in the insertion direction is smaller than a gap in the perpendicular direction. (Appendix 5) 5. The sheet feeding device according to claim 2, wherein the hole is an elongated hole or an elliptical hole whose longitudinal direction is the orthogonal direction and whose lateral direction is the insertion direction. (Appendix 6) The sheet feeding device described in any one of Appendix 2 to Appendix 5, characterized in that the engagement pin has a small diameter portion guided by the guide portion and a large diameter portion as the insertion portion in which a regulating member is installed to regulate the movement of the engagement pin in the protruding direction. (Appendix 7) The sheet feeding device described in Appendix 6, characterized in that the regulating member is a retaining ring that is installed in a circumferential groove formed in the large diameter portion and has an outer diameter larger than that of the large diameter portion. (Appendix 8) The sheet feeding device according to any one of Supplementary Note 2 to Supplementary Note 7, wherein the feeding cassette is formed with a limiting portion that limits movement of the engagement pin in a direction opposite to the protruding direction. (Appendix 9) When the gap between the engagement pin and the hole portion in the perpendicular direction is C and the gap between the engagement pin and the guide portion in the perpendicular direction is D, D <C 9. The sheet feeding device according to claim 2, wherein the following relationship holds: (Appendix 10) When the hole depth of the hole portion is E and the distance from the inner wall surface of the feeding cassette where the hole portion is formed to the outer wall surface of the device body where the guide portion is formed is F, D <C×F / E 10. The sheet feeding device according to claim 9, wherein the following relationship holds: (Appendix 11) The sheet feeding device described in any one of Appendix 1 to Appendix 10, characterized in that, if the engagement pin is held in a fixed state in the feeding cassette, the retraction mechanism is configured to retract the engagement pin in an engaged state while tracing an arc-shaped trajectory centered on a fulcrum away from the guide portion. (Appendix 12) The retraction mechanism includes: an arm member having an engagement groove with which the engagement pin is freely engaged, the arm member being rotatable about a fulcrum spaced apart from the guide portion; a biasing member that biases the arm member so that the engagement pin engaged with the engagement groove is pulled in the insertion direction; 12. The sheet feeding device according to claim 1, further comprising: (Appendix 13) The orthogonal direction is a vertical direction, the feeding cassette includes a protruding portion protruding in the insertion direction at an end portion in a width direction as the protruding direction, the end portion being located downstream in the insertion direction, The engagement pin is formed so as to protrude horizontally toward a center portion in the width direction at the protruding portion, 13. The sheet feeding device according to claim 1, wherein the guide portion is a groove portion whose groove width direction is the up-down direction. (Appendix 14) the feeding cassette is formed with a hole into which the insertion portion of the engagement pin is inserted, The sheet feeding device according to any one of claims 1 to 13, wherein the insertion portion is formed in a drum shape. (Appendix 15) An image forming apparatus comprising the sheet feeding device according to any one of claims 1 to 14. [Prior art documents] [Patent documents]

[0056] [Patent Document 1] Patent No. 6373054

Claims

1. A feeding cassette is provided which is insertable into and removable from the main body of the device, the feeding cassette is provided with an engagement pin that protrudes in a protruding direction perpendicular to a direction of insertion into the apparatus body, The device body includes: a guide portion extending in the insertion direction and configured to guide the engagement pin when the feeding cassette is inserted; a retraction mechanism that retracts the engagement pin in the insertion direction toward a predetermined position in the guide portion while the engagement pin is engaged; Equipped with The sheet feeding device according to claim 1, wherein the engagement pin is held in the feeding cassette in a non-fixed manner and movable in a direction perpendicular to the insertion direction and the protruding direction.

2. The feeding cassette includes: A hole into which the insertion portion of the engagement pin is inserted is formed, The sheet feeding device according to claim 1, characterized in that, with a gap in the perpendicular direction between the insertion portion and the hole portion, the engagement pin is held so as to be tiltable with respect to the protruding direction and slidable in the perpendicular direction.

3. The sheet feeding device according to claim 2, characterized in that the feeding cassette holds the engagement pin so that it can be tilted relative to the protruding direction and can slide in the insertion direction with a gap between the hole portion and the insertion portion in the insertion direction.

4. 4. The sheet feeding device according to claim 3, wherein the hole is formed so that a gap in the insertion direction is smaller than a gap in the perpendicular direction.

5. 4. The sheet feeding device according to claim 3, wherein the hole is an elongated hole or an elliptical hole whose longitudinal direction is the orthogonal direction and whose lateral direction is the insertion direction.

6. The sheet feeding device according to claim 2, characterized in that the engagement pin has a small diameter portion guided by the guide portion and a large diameter portion as the insertion portion in which a regulating member for regulating movement of the engagement pin in the protruding direction is installed.

7. 7. The sheet feeding device according to claim 6, wherein the regulating member is a retaining ring that is installed in a circumferential groove formed in the large diameter portion and has an outer diameter larger than that of the large diameter portion.

8. 7. The sheet feeding device according to claim 6, wherein the feeding cassette is formed with a limiting portion that limits movement of the engagement pin in a direction opposite to the protruding direction.

9. When a gap between the engagement pin and the hole portion in the perpendicular direction is defined as C and a gap between the engagement pin and the guide portion in the perpendicular direction is defined as D, D < C 4. The sheet feeding apparatus according to claim 2, wherein the following relationship is established:

10. When the hole depth of the hole portion is E and the distance from the inner wall surface of the feeding cassette in which the hole portion is formed to the outer wall surface of the device main body in which the guide portion is formed is F, D < C x F / E 10. The sheet feeding apparatus according to claim 9, wherein the following relationship is satisfied:

11. 3. The sheet feeding device according to claim 1, wherein the retraction mechanism is configured to retract the engagement pin in an engaged state while tracing an arc-shaped trajectory centered on a fulcrum spaced from the guide portion, if the engagement pin is held in a fixed state in the feeding cassette.

12. The retraction mechanism includes: an arm member having an engagement groove with which the engagement pin is freely engaged, the arm member being rotatable about a fulcrum spaced apart from the guide portion; a biasing member that biases the arm member so that the engagement pin engaged with the engagement groove is pulled in the insertion direction; 3. The sheet feeding device according to claim 1, further comprising:

13. The orthogonal direction is a vertical direction, the feeding cassette includes a protruding portion protruding in the insertion direction at an end portion in a width direction as the protruding direction, the end portion being located downstream in the insertion direction, The engagement pin is formed so as to protrude horizontally toward a center portion in the width direction at the protruding portion, 3. The sheet feeding device according to claim 1, wherein the guide portion is a groove portion whose width direction is the vertical direction.

14. the feeding cassette is formed with a hole into which the insertion portion of the engagement pin is inserted, The sheet feeding device according to claim 1 , wherein the insertion portion is formed in a drum shape.

15. 3. An image forming apparatus comprising the sheet feeding device according to claim 1.

Images