Sheet Feeding Device and Image Forming Apparatus

Abstract

To reduce possibility of creep deformation of an elastic engaging member.SOLUTION: A sheet feeding device has: a positioning part (32) provided on a device body; a positioned part (31) provided in a sheet storage part for positioning the sheet storage part with respect to an intersection direction perpendicular to an attachment and detachment direction (Y) of the sheet storage part; an engaged member (41) provided on the body; and an engaging member (42) provided in the sheet storage part, formed of an elastic material, and holding the sheet storage part in a mounting position in the attachment and detachment direction by engaging with the engaged member. The engaging member can swing in a crossing direction (X).SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a sheet feeding device for feeding a sheet and an image forming device for forming an image on the sheet.

Background Art

[0002] In image forming apparatuses such as copiers, printers, and facsimiles, a configuration is widely used in which a sheet storage unit (also called a feeding cassette, a feeding tray, etc.) for storing sheets is detachably attached to the apparatus main body, and the sheets in the sheet storage unit are automatically fed one by one. Patent Document 1 describes a configuration in which an engaging member formed of an elastic plastic material is provided on the apparatus main body of the image forming apparatus, and an engaged member to be engaged by the engaging member is provided on the paper feed tray. When the paper feed tray is inserted into the apparatus main body, the engaged member is sandwiched between the two finger portions of the engaging member, so that the paper feed tray is drawn in and the paper feed tray is positioned with respect to the attachment / detachment direction to the apparatus main body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention is a further development of the conventional technology, and an object thereof is to provide a sheet feeding device and an image forming device capable of reducing the possibility of creep deformation of an engaging member in a configuration in which a sheet storage unit is positioned by an elastic engaging member.

Means for Solving the Problems

[0005] One aspect of the present invention is a sheet feeding device having a device main body, a sheet storage portion that is detachably attached to the device main body and stores a fed sheet, a positioning shaft provided on either the device main body or the sheet storage portion and extending in the attachment / detachment direction of the sheet storage portion with respect to the device main body, and a hole portion provided on the other of the device main body and the sheet storage portion. In a state where the sheet storage portion is pulled out, the positioning shaft does not fit into the hole portion. In a process of moving the sheet storage portion toward the mounting position within the device main body, the positioning shaft fits into the hole portion. In a state where the sheet storage portion is mounted at the mounting position, the sheet storage portion is positioned in a crossing direction that perpendicularly intersects the attachment / detachment direction when viewed in the gravitational direction by the fitting of the positioning shaft and the hole portion. The sheet feeding device further includes an engaged member provided on the device main body and an engaging member provided on the sheet storage portion, formed of an elastic material, and elastically deformed as the sheet storage portion is attached to the device main body. The engaging member engages with the engaged member to hold the sheet storage portion at the mounting position with respect to the attachment / detachment direction. The engaging member is swingable in the crossing direction, and in a state where the sheet storage portion is mounted at the mounting position , the position of the positioning shaft in the intersecting direction is separated from the position of the engaging member in the intersecting direction, and in the attachment / detachment direction former the above-mentioned positioning shaft position and in the attaching / detaching direction the engaging member position are arranged so as to overlap each other. The sheet feeding device is characterized by this.

[0006] Another aspect of the present invention includes a device main body, a sheet storage unit that is detachably attached to the device main body and stores sheets to be fed, a positioning shaft provided on either the device main body or the sheet storage unit and extending in the attachment / detachment direction of the sheet storage unit with respect to the device main body, and a hole portion provided on the other of the device main body and the sheet storage unit. In a state where the sheet storage unit is pulled out, the positioning shaft is not fitted into the hole portion. In a process of moving the sheet storage unit toward the mounting position within the device main body, the positioning shaft is fitted into the hole portion. In a state where the sheet storage unit is mounted at the mounting position, the sheet storage unit is positioned in a crossing direction perpendicular to the attachment / detachment direction when viewed in the gravitational direction by the fitting of the positioning shaft and the hole portion. A sheet feeding device further includes an engaged member provided on the sheet storage unit and an engaging member provided on the device main body, formed of an elastic material, and elastically deformed and engaged with the engaged member as the sheet storage unit is attached to the device main body. The engaging member holds the sheet storage unit at the mounting position with respect to the attachment / detachment direction. The engaging member is swingable in the crossing direction. In a state where the sheet storage unit is mounted at the mounting position , the position of the positioning shaft in the intersecting direction is separated from the position of the engaging member in the intersecting direction, and in the attachment / detachment direction former the above-mentioned positioning shaft position and in the attaching / detaching direction the engaging member position are arranged so as to overlap with each other. A sheet feeding device is characterized by this.

Advantages of the Invention

[0007] According to the present invention, the possibility of creep deformation of the engaging member can be reduced.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0009] Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings.

Example

[0010] FIG. 1 is a schematic diagram showing a cross-sectional configuration of a full-color laser beam printer (hereinafter referred to as printer 201), which is an image forming apparatus according to Example 1. The printer 201 forms an image on a sheet P used as a recording medium based on image information input from an external device or image information read from a document. The sheets used as the recording medium include papers such as paper and envelopes, plastic films for overhead projectors, and cloth.

[0011] The printer 201 includes a printer main body 201A that houses an image forming unit 201B, and an image reading device 202 that is disposed above the printer main body 201A and reads image information from a document. A discharge space S through which the image-formed sheet P is discharged is formed between the image reading device 202 and the printer main body 201A in the vertical direction (gravity direction).

[0012] An image forming unit 201B, which is an example of an image forming means, is an intermediate transfer type electrophotographic unit including four process cartridges 211 and an intermediate transfer unit 201C. Each process cartridge 211 forms a toner image on the surface of a photosensitive drum 212 by an electrophotographic process. That is, when creation of a toner image is requested for the image forming unit 201B, the photosensitive drum 212, which is an image carrier (electrophotographic photoreceptor), is rotationally driven, and a charging device 213 uniformly charges the surface of the photosensitive drum 212. An exposure device 210 provided at the lower part of the printer main body 201A irradiates the photosensitive drum 212 with laser light based on image information to expose the drum surface and writes an electrostatic latent image on the photosensitive drum 212. A developing device 214 develops the electrostatic latent image on the drum surface into a toner image using a developer containing charged toner particles on the photosensitive drum 212. The toner images of respective colors formed in the four process cartridges 211 are primarily transferred from the photosensitive drum 212 to an intermediate transfer belt 216 by a primary transfer roller 219. Adhered matter such as toner remaining on the photosensitive drum 212 is removed by a cleaning device provided in each process cartridge 211.

[0013] The intermediate transfer unit 201C has an intermediate transfer belt 216 which is an intermediate transfer body. The intermediate transfer belt 216 is wound around a secondary transfer inner roller 216a, a tension roller 216b, etc., and is rotationally driven in the counterclockwise direction in the figure. The toner image carried on the intermediate transfer belt 216 is secondarily transferred to a sheet P in a secondary transfer portion formed between a secondary transfer roller 217 facing the secondary transfer inner roller 216a with the intermediate transfer belt 216 interposed therebetween. Adhered matter such as toner remaining on the intermediate transfer belt 216 is removed by a cleaning device.

[0014] The sheet P onto which the toner image has been transferred is delivered to the fixing device 220. The fixing device 220, which is the fixing means in this embodiment, includes a fixing roller 161 as a heating member, a pressure roller 162 that sandwiches the sheet together with the fixing roller, and a heating element 163 (for example, a halogen lamp) as heating means for heating the toner image on the sheet. The fixing device 160 melts the toner by applying heat and pressure to the toner image while transporting the sheet P, and then the image is fixed to the sheet P when the toner adheres.

[0015] In parallel with such an image forming process, the sheets P are fed one by one from the cassette feeding unit 230 or the multi-feeding unit 300 toward the sheet P. The cassette feeding unit 230 includes a feeding cassette 1 in which the sheets P are stacked, and a feeding unit that feeds the sheet P from the feeding cassette 1. The feeding unit includes a pickup roller 8 that sends out the sheet P from the feeding cassette 1, and a feed roller 9 (feeding roller) that transports the sheet P received from the pickup roller 8. Further, a retard roller 7 is provided that abuts against the feed roller 9 to form a nip portion, and separates the sheets P fed by the feed roller 9 one by one by applying a frictional force to the sheet P at the nip portion.

[0016] The driving force of the retard roller 7 in a direction opposite to the rotation of the feed roller 9 is input via a torque limiter. When there is one sheet P passing through the nip portion, the torque limiter slips and the retard roller 7 rotates following the feed roller 9. On the other hand, when a plurality of sheets P enter the nip portion, the retard roller 7 rotates in a direction opposite to the rotation of the feed roller 9 and pushes the sheet P back into the feeding cassette 1. Such a retard roller 7 is an example of a separating member for separating the sheet P, and a roller member connected to a fixed shaft via a torque limiter may be used, or a pad-shaped elastic member may be used.

[0017] The multi-feed unit 300 includes a multi-tray 13 as a sheet support means and a feed unit that feeds the sheet P set on the multi-tray 13. The configuration of the feed unit of the multi-feed unit 300 is basically the same as that of the feed unit of the cassette feed unit 230. The multi-tray 13 is also called a multi-purpose tray or a manual feed tray.

[0018] The sheet P fed from the cassette feed unit 230 or the multi-feed unit 300 is conveyed to the registration roller pair 240 via the sheet conveyance path in the printer main body 201A and is skew-corrected by the stationary registration roller pair 240. The skew-corrected sheet P is conveyed by the registration roller pair 240 to the secondary transfer unit at a timing synchronized with the image forming process by the image forming unit 201B.

[0019] The sheet P on which an image is formed by passing through the secondary transfer unit and the fixing unit 220 is discharged to the discharge space S by the first discharge roller pair 225a or the second discharge roller pair 225b and is stacked on the stacking unit 223 provided above the printer main body 20A. In the case of double-sided printing, the sheet P on which an image is formed on the first side is reversely conveyed (switchback conveyance) by the reverse roller pair 222 and is delivered to the double-sided conveyance unit 201D, and is conveyed again to the registration roller pair 24 via the re-conveyance path R. Thereafter, the sheet P on which an image is formed on the second side by passing through the secondary transfer unit and the fixing unit 220 is discharged to the discharge space S by the first discharge roller pair 225a or the second discharge roller pair 225b and is stacked on the stacking unit 223.

[0020] The above-described image forming operation is controlled by a control unit mounted on the printer main body 201A. Also, in the above description, the image forming unit 201B is an example of an image forming means, and a direct transfer type electrophotographic unit, an inkjet type or an offset printing type image forming unit may be used.

[0021] (Sheet Feeding Device) The cassette feeding unit 230, which is the sheet feeding device of this embodiment, will be further described. FIG. 2 is a perspective view showing the feeding cassette 1. The feeding cassette 1 as a sheet storage unit (also called a sheet loading means) is detachably attached to the printer main body 201A (FIG. 1) as the apparatus main body. Specifically, the feeding cassette 1 is pulled out in the pulling-out direction Y1 while being guided by the guide portion 2g along the rails provided on the printer main body 201A by the operation of the gripping portion 1F, and is attached (inserted) in the mounting direction Y2 opposite to the pulling-out direction Y1. Hereinafter, the pulling-out direction Y1 and the mounting direction Y2 are referred to as the attachment / detachment direction Y of the feeding cassette 1. Note that the pulling-out direction Y1 is the front direction of the printer 201 shown in FIG. 1, the pulling-out direction Y1 is the rear (depth direction) of the printer 201, and the attachment / detachment direction Y is the front-rear direction of the printer 201.

[0022] The sheets stacked on the feeding cassette 1 are fed from the feeding cassette 1 in the conveying direction X1 by the feed roller 9 and the like described with reference to FIG. 1. The conveying direction X1 of this embodiment is an intersecting direction that intersects the attachment / detachment direction Y perpendicularly when viewed from above. Hereinafter, the conveying direction X1 and the opposite direction X2 are referred to as the left-right direction X of the feeding cassette 1. Note that the left-right direction X is also the left-right direction when the printer 201 shown in FIG. 1 is viewed from the front.

[0023] The sheet feeding cassette 1 has a cassette frame 2 in a substantially box shape (tray shape) with an open upper side, a loading plate 21, side regulating portions 20F and 20R, and a rear end regulating portion 11. The loading plate 21 is rotatably supported by the cassette frame 2 and can move up and down with a sheet loaded on its upper surface. The side regulating portions 20F and 20R are provided on one side and the other side in the sheet width direction (i.e., the attachment / detachment direction Y) perpendicular to the conveyance direction X1, and are movably attached along the sheet width direction to a rail 2b provided at the bottom 2a of the cassette frame 2. The rear end regulating portion 11 is movably attached along the conveyance direction X1 to a rail 2c provided at the bottom 2a of the cassette frame 2. The side regulating portions 20F and 20R and the rear end regulating portion 11 regulate the position of the sheet set in the sheet feeding cassette 1 by abutting against the end of the sheet loaded on the loading plate 21. Also, by changing the positions of the side regulating portions 20F and 20R and the rear end regulating portion 11 according to the sheet size, sheets of various sizes can be stored in the sheet feeding cassette 1.

[0024] (Positioning portion and engaging portion) Next, a configuration for holding and positioning the sheet feeding cassette 1 in the mounted state will be described with reference to FIGS. 3(a) to 3(d). The left side of FIGS. 3(a) to 3(d) is a cross-sectional view of the rear portion of the sheet feeding cassette 1 (the downstream portion in the mounting direction Y2) and a part of the printer main body 201A as viewed from above. The right side of FIGS. 3(a) to 3(d) is a cross-sectional view of the front portion of the sheet feeding cassette 1 (the upstream portion in the mounting direction Y2) and another part of the printer main body 201A as viewed from above.

[0025] As shown on the left side of FIG. 3(a), an engaging arm 42 as an engaging member is provided at the rear portion of the sheet feeding cassette 1. In the printer main body 201A, a boss member 41 as an engaged member is provided on the rear side (the downstream side in the mounting direction Y2) of a space for accommodating the sheet feeding cassette 1 (hereinafter referred to as a cassette mounting space). The engaging arm 42 and the boss member 41 constitute an engaging portion 40 that pulls the sheet feeding cassette 1 into the mounting position in the printer main body 201A (inside the apparatus body) and positions the sheet feeding cassette 1 in the attachment / detachment direction Y.

[0026] In addition, a positioning shaft 31 as a first positioned part is provided at the rear part of the paper feed cassette 1. In the printer main body 201A, a bearing part 32 as a first positioning part is provided on the rear side of the cassette mounting space. The positioning shaft 31 and the bearing part 32 constitute a back-side positioning mechanism 30 (first positioning mechanism) for positioning the paper feed cassette 1 in the left-right direction X.

[0027] As shown on the right side of Fig. 3(a), a positioning shaft 34 as a second positioned part is provided at the front part of the paper feed cassette 1. In the printer main body 201A, a bearing part 35 as a second positioning part is provided at a position facing the positioning shaft 34. The positioning shaft 34 and the bearing part 35 constitute a front-side positioning mechanism 33 for positioning the paper feed cassette 1 in the left-right direction X.

[0028] These engaging parts 40, the back-side positioning mechanism 30, and the front-side positioning mechanism 33 have a function of restricting the movement of the paper feed cassette 1 mounted at a predetermined mounting position in the printer main body 201A and holding it at the mounting position. Hereinafter, the constituent members of the engaging parts 40, the back-side positioning mechanism 30, and the front-side positioning mechanism 33 will be described in detail.

[0029] (1) Engaging parts The engaging arm 42 protrudes from the cassette frame 2 to the downstream side in the mounting direction Y2, and is supported by the cassette frame 2 so as to be swingable about a swing axis 43. The swing axis 43 is preferably an axis extending in the vertical direction (gravity direction). The boss member 41 is a substantially columnar member extending in the vertical direction, which is a direction substantially parallel to the swing axis 43 of the engaging arm 42, and is fixed to the frame of the printer main body 201A.

[0030] The engaging arm 42 has two claw portions 42a (arm portions) and guide portions 42b provided at the tips of the respective claw portions 42a. A locking portion 42d, which is a recess for receiving the boss member 41, is formed by the two claw portions 42a (see also Fig. 6(a)). The locking portion 42d is provided, for example, as an arcuate surface (a part of a cylindrical surface with a central angle greater than 180 degrees) when viewed from above. The inner diameter of the locking portion 42d is set to be substantially equal to the outer diameter of the boss member 41 when viewed from above.

[0031] The locking portion 42d is a concave shape that opens toward the downstream side in the mounting direction Y2 through an opening between two narrow portions 42c located at the boundary between the claw portion 42a and the guide portion 42b when viewed from above. The distance between the two narrow portions 42c, which is the opening width of the engaging arm 42, is set to be smaller than the width of the boss member 41 in the left - right direction X. The two guide portions 42b are formed such that the interval in the left - right direction X increases as they go downstream from the narrow portion 42c in the mounting direction Y2, and the interval in the left - right direction X at the downstream end in the mounting direction Y2 is larger than the maximum width of the boss member 41.

[0032] The two claw portions 42a have elasticity that allows them to elastically deform so that the distance of the narrow portion 42c expands to a width through which the boss member 41 can pass when the guide portion 42b is pressed by the boss member 41.

[0033] (2) Rear - side positioning mechanism and front - side positioning mechanism As shown on the left side of Fig. 3(a), the positioning shaft 31 is a member supported by the cassette frame 2 and extending in the mounting direction Y2. The positioning shaft 31 has a cylindrical portion 31b with a constant outer diameter and a tapered portion 31a that continuously extends from the cylindrical portion 31b in the mounting direction Y2 and whose outer diameter decreases in the mounting direction Y2. The tapered portion 31a has a guiding function for realizing a smooth fitting between the positioning shaft 31 and the bearing portion 32.

[0034] The bearing portion 32 is fixed to the frame of the printer main body 201A, and is a portion that forms a hole extending in the mounting direction Y2 at a position facing the positioning shaft 31. The inner diameter of the bearing portion 32 is set to be substantially equal to the outer diameter of the cylindrical portion 31b of the positioning shaft 31.

[0035] As shown on the right side of Fig. 3(a), the positioning shaft 34 is supported by the cassette frame 2 and is a member extending in the mounting direction Y2. The positioning shaft 34 has a cylindrical portion 34b with a constant outer diameter, and a tapered portion 34a that continuously extends from the cylindrical portion 34b in the mounting direction Y2 and whose outer diameter decreases toward the mounting direction Y2. The tapered portion 34a has a guiding function for realizing a smooth fitting between the positioning shaft 34 and the bearing portion 35.

[0036] The bearing portion 35 is fixed to the frame of the printer main body 201A, and is a portion that forms a hole extending in the mounting direction Y2 at a position facing the positioning shaft 34. The inner diameter of the bearing portion 35 is set to be substantially equal to the outer diameter of the cylindrical portion 34b of the positioning shaft 34.

[0037] The difference between the inner diameters of the bearing portions 32 and 35 and the outer diameters of the cylindrical portions 31b and 34b of the positioning shafts 31 and 34 determines the positioning accuracy of the feed cassette 1 in the left - right direction X in the mounted state. The difference between the inner diameters of the bearing portions 32 and 35 and the outer diameters of the cylindrical portions 31b and 34b of the positioning shafts 31 and 34 is smaller than the play in the left - right direction X at the engaging portion between the rail of the printer main body 201A and the guide portion 2g (Fig. 2) of the feed cassette 1. Note that instead of the tapered portions 31a and 34a, tapered portions whose inner diameters widen toward the upstream side in the mounting direction Y2 may be arranged in the bearing portions 32 and 35 to provide a guiding function.

[0038] (Operation during cassette attachment and detachment) The operations of the engaging portion 40, the rear - side positioning mechanism 30, and the front - side positioning mechanism 33 when mounting the feed cassette 1 will be described with reference to Figs. 3(a - d).

[0039] Fig. 3(a) shows the state during the process of inserting the ejected feed cassette 1 in the mounting direction Y2 toward the mounting position on the printer main body 201A. In the back positioning mechanism 30 and the front positioning mechanism 33, first, the tapered portions 31a, 34a of the positioning shafts 31, 34 enter the bearing portions 32, 35. The engagement arm 42 is not yet in contact with the boss member 41.

[0040] As shown in Fig. 3(b), as the feed cassette 1 moves in the mounting direction Y2, the feed cassette 1 is guided by the tapered portions 31a, 34a so that the center lines of the positioning shafts 31, 34 coincide with the center lines of the bearing portions 32, 35. Also, the guide portion 42b of the engagement arm 42 comes into contact with the outer peripheral surface of the boss member 41. Here, if the opening of the engagement arm 42 does not face the center of the boss member 41, one of the guide portions 42b comes into contact with the boss member 41 first, causing the engagement arm 42 to swing so that the opening faces the center of the boss member 41.

[0041] As shown in Fig. 3(c), when the feed cassette 1 further moves in the mounting direction Y2, the cylindrical portions 31b, 34b of the positioning shafts 31, 34 begin to fit with the bearing portions 32, 35. Also, as the boss member 41 presses the guide portion 42b, the two claw portions 42a elastically deform so that the narrow portion 42c expands. As a result, the portion with the largest width of the boss member 41 passes through the narrow portion 42c. After passing through the narrow portion 42c, the two claw portions 42a tend to narrow due to the elastic force, so the boss member 41 is guided to the back side of the locking portion 42d, and a force (drawing force) in the mounting direction Y2 acts on the feed cassette 1.

[0042] As shown in Fig. 3(d), when the center of the boss member 41 reaches a position where it substantially coincides with the center of the locking portion 42d, the movement of the feeding cassette 1 in the mounting direction Y2 stops. In this state, since the boss member 41 abuts against the locking portion 42d, the further movement of the feeding cassette 1 in the mounting direction Y2 is restricted. Also, since the elastic forces of the two claw portions 42a act in a direction to restrict the detachment of the boss member 41, the movement of the feeding cassette 1 in the drawing-out direction Y1 is also restricted. Therefore, by the engagement of the engaging arm 42 and the boss member 41, the feeding cassette 1 is held in the mounted state and the feeding cassette 1 is positioned with respect to the attachment / detachment direction Y.

[0043] Also, in the rear positioning mechanism 30 and the front positioning mechanism 33, the cylindrical portions 31b, 34b of the positioning shafts 31, 34 are fitted into the bearing portions 32, 35. Thereby, the feeding cassette 1 is positioned in the left-right direction X that intersects the attachment / detachment direction Y. Also, since the positioning in the left-right direction X is performed on both the rear side and the front side in the mounting direction Y2, the turning (rotation when viewed from above) of the feeding cassette 1 is also restricted.

[0044] Note that the start of the fitting of the cylindrical portions 31b, 34b of the positioning shafts 31, 34 into the bearing portions 32, 35 is set at a timing after the portion of the boss member 41 with the largest width has passed through the narrow portion 42c of the engaging arm 42 and before the boss member 41 reaches the locking portion 42d. Thereby, the feeding cassette 1 can be held at the mounting position while ensuring the positioning accuracy of the feeding cassette 1 in the left-right direction X.

[0045] (Swing range of the engaging arm) With reference to Figs. 4(a, b), the swing range in which the engaging arm 42 in the present embodiment can swing will be described. Figs. 4(a, b) are views of the periphery of the engaging arm 42 as seen from above, and represent the state immediately before the guide portion 42b contacts the boss member 41 when the feeding cassette 1 is inserted from the upstream side to the downstream side in the mounting direction Y2.

[0046] In Fig. 4(a), the engagement arm 42 is at the limit angle in the clockwise direction within the swing range, and in Fig. 4(b), the engagement arm 42 is at the limit angle in the counterclockwise direction within the swing range. The cassette frame 2 is provided with regulating surfaces 45a and 45b as regulating parts, and when the contact part of the engagement arm 42 contacts either of the regulating surfaces 45a and 45b, the swing range of the engagement arm 42 is restricted.

[0047] The swing range of the engagement arm 42 is set so that the boss member 41 can be guided by the guide part 42b regardless of the angle at which the engagement arm 42 is located within the swing range. That is, in either state of Figs. 4(a) and 4(b), the swing range is restricted so that the boss member 41 is located in the region 44 inside the virtual line that spreads in a V shape toward the downstream side in the mounting direction Y2 along the two guide parts 42b. Thereby, regardless of the angle of the engagement arm 42 before the feeding cassette 1 is mounted, the engagement arm 42 can engage with the boss member 41 more reliably in response to the mounting of the feeding cassette 1.

[0048] (Absorption of tolerances etc. due to the swing of the engagement arm) Also, the swing range of the engagement arm 42 is set in consideration of variations in the positional relationship between members due to component tolerances, assembly tolerances, etc. The absorption of variations due to the swing of the engagement arm 42 will be described with reference to Figs. 5(a) to 5(c).

[0049] As shown in Fig. 5(a), the distance in the left - right direction X (distance between the centers) between the positioning bearing part 32 and the boss member 41 is composed of the nominal distance D1. Correspondingly, with the engagement arm 42 in the neutral position (the center of the swing range), the engagement arm 42 and the positioning shaft 31 are arranged so that the distance from the center of the positioning shaft 31 to the center of the locking part 42d of the engagement arm 42 is equal to the nominal distance D1.

[0050] As shown in FIG. 5(b), assume that due to component tolerances, assembly tolerances, etc., the distance D2 in the left-right direction X between the bearing portion 32 and the boss member 41 becomes larger than the nominal distance D1. In this case, the engaging arm 42 engages with the boss member 41 in a state where the engaging arm 42 swings counterclockwise around the swing axis 43. Further, as shown in FIG. 5(c), assume that due to component tolerances, assembly tolerances, etc., the distance D3 in the left-right direction X between the bearing portion 32 and the boss member 41 becomes smaller than the nominal distance D1. In this case, the engaging arm 42 engages with the boss member 41 in a state where the engaging arm 42 swings clockwise around the swing axis 43.

[0051] If the engaging arm 42 is a member fixed to the cassette frame 2, assume that in the situation shown in FIG. 5(b) or (c), the engaging arm 42 and the positioning shaft 31 are engaged with the boss member 41 and the bearing portion 32, respectively. In this case, due to the difference between the distance between the engaging arm 42 and the positioning shaft 31 and the distance between the boss member 41 and the bearing portion 32, stress acts on each member, and creep deformation may occur in the claw portion 42a of the engaging arm 42. Further, when the feeding cassette 1 is mounted, the end of the guide portion 42b of the engaging arm 42 or the positioning shaft 31 may collide with the boss member 41 or the bearing portion 32, resulting in damage to the members. When such deformation or damage of the members occurs, the functions of pulling-in and positioning by the engaging portion 40 and positioning by the back-side positioning mechanism 30 are degraded, and there is a concern that the attachment and detachment of the feeding cassette 1 may be hindered.

[0052] On the other hand, in this embodiment, since the variation in the positional relationship between members due to component tolerances, assembly tolerances, etc. is absorbed by the engaging arm 42 that can swing in a direction intersecting the attachment / detachment direction Y, the possibility of deformation and damage of the members is reduced. Therefore, the degradation of the functions of pulling-in and positioning by the engaging portion 40 and the back-side positioning mechanism 30 is suppressed, and the feeding cassette 1 can be attached and detached smoothly.

[0053] (Reduction of creep deformation, etc. in the cassette-mounted state) In addition, in this embodiment, since the engagement arm 42 is configured to be swingable in the left - right direction X, it is explained that creep deformation of the engagement arm 42 can be reduced even when a force in the left - right direction X acts on the feeding cassette 1 in the mounted state of the feeding cassette 1.

[0054] As an example of the force in the left - right direction X acting on the feeding cassette 1 in the cassette - mounted state, there is an urging member used in a mechanism that moves a roller member for sheet conveyance in conjunction with the attachment and detachment of the feeding cassette 1. The urging spring 4 shown in FIG. 1 is an example of the urging member and urges the roller separation lever 3 as the pressed member. The roller separation lever 3 has a pressed portion 3a that protrudes into the cassette mounting space by the urging force of the urging spring 4 in the state where the feeding cassette 1 is pulled out, and swings when pressed by a pressing portion 2d provided on the feeding cassette 1 as the feeding cassette 1 is mounted.

[0055] Here, the pickup roller 8 is rotatably held by the roller holder 18, and since the roller holder 18 is swingably supported with respect to the frame of the printer main body 201A, the retard roller 7 is configured to be able to move up and down (able to contact and separate from the sheet). Also, the retard roller 7 is rotatably supported by the roller holder 17, and since the roller holder 17 is swingably supported with respect to the frame of the printer main body 201A, the retard roller 7 can contact and separate from the feed roller 9.

[0056] The roller holders 18 and 17 are configured to move in conjunction with the roller separation lever 3. That is, in a state where the feeding cassette 1 is attached to the printer main body 201A, the pressed portion 3a is pressed by the pressing portion 2d, so that the roller separation lever 3 is held at the position shown in FIG. 1 against the biasing force of the biasing spring 4. In this state, the pickup roller 8 is held at a feeding position where it can contact the upper surface of the sheet P in the feeding cassette 1, and the retard roller 7 is held at a contact position where it contacts the feed roller 9. On the other hand, when the feeding cassette 1 is pulled out from the printer main body 201A, the roller separation lever 3 rotates according to the biasing force of the biasing spring 4 by being released from the pressing by the pressed portion 3a. In this state, the pickup roller 8 retracts to a retracted position above the feeding position, and the retard roller 7 moves to a separated position separated from the feed roller 9.

[0057] As a mechanism for moving the roller holders 18 and 17 in conjunction with the roller separation lever 3, a known one can be applied. For example, as illustrated in JP-A-2018-80047, the roller separation lever 3 presses a pressed portion provided on the roller holder 17, causing the roller holder 17 to swing, and another lever member pressed by the roller separation lever 3 causes the roller holder 18 to swing. Further, the roller separation lever 3 and the biasing spring 4 shown in FIG. 1 are schematic, and the shape, arrangement, direction of the rotation axis, rotation direction, etc. can be appropriately changed.

[0058] By the way, in a state where the feeding cassette 1 is attached, the biasing force of the biasing spring 4 presses the roller separation lever 3 toward the left side in the drawing (the direction X2 opposite to the conveyance direction X1 of the sheet P) of the feeding cassette 1. If such a pressing force acts on the engaging portion 40 over a long period of time, creep deformation may occur in the claw portion 42a of the engaging arm 42, the function of pulling in and positioning by the engaging portion 40 may deteriorate, and there is a concern that the attachment and detachment of the feeding cassette 1 may be hindered.

[0059] In contrast, in this embodiment, the rear positioning mechanism 30 and the front positioning mechanism 33 position the feeding cassette 1 in the left-right direction X, and the engaging arm 42 is configured to be swingable in the left-right direction X. Therefore, the biasing force of the biasing spring 4 can be received by the rear positioning mechanism 30 and the front positioning mechanism 33, and the possibility of creep deformation occurring in the claw portion 42a of the engaging arm 42 can be reduced. That is, according to this embodiment, when a biasing member is used in a part of the mechanism that moves the roller member in conjunction with the attachment and detachment of the feeding cassette 1, the possibility of creep deformation occurring in the engaging member due to the biasing force of the biasing member can be reduced.

[0060] (Mounting configuration of the engaging arm) Here, the mounting configuration of the engaging arm 42 with respect to the feeding cassette 1 will be described with reference to FIGS. 6(a) and 6(b). FIG. 6(a) is a perspective view showing the engaging arm 42 in the mounted state, and FIG. 6(b) is an exploded view showing the mounting method of the coupling pin 50 as the mounting member according to this embodiment.

[0061] As shown in FIG. 6(b), the cassette frame 2 of the feeding cassette 1 is provided with a coupling hole 51 penetrating in the vertical direction. Also, the engaging arm 42 is provided with a hole penetrating in the vertical direction. The coupling pin 50 is a substantially cylindrical member and is mounted from above so as to penetrate the coupling hole 51 and the hole of the engaging arm. In the mounted state shown in FIG. 6(a), the engaging arm 42 swings with the center of the coupling pin 50 as the swing axis 43. With such a configuration, the engaging arm 42 as a swingable engaging member can be easily mounted.

[0062] Note that the coupling pin 50 inserted into the coupling hole 51 is fixed to the cassette frame 2 by a snap fit configuration (not shown). Also, the coupling pin 50 can be easily removed from the cassette frame 2 by pressing it in the direction of arrow C from below. That is, the coupling pin 50 is detachable with respect to the feeding cassette 1.

Embodiment

[0063] As Example 2, a configuration example will be described in which the engaging arm 42 as the engaging member is arranged on the printer main body 201A, and the boss member 41 as the engaged member is arranged on the feeding cassette 1. Hereinafter, elements denoted by the same reference numerals as those in Example 1 have substantially the same configuration and operation as those in Example 1, and the parts different from Example 1 will be described.

[0064] As shown in FIG. 7, the engaging arm 42 of the present embodiment is supported by the frame of the printer main body 201A and can swing in a direction (preferably the left - right direction X) intersecting the attachment / detachment direction Y of the feeding cassette 1 around the swing axis 43. On the other hand, the boss member 41 is attached to the cassette frame 2 of the feeding cassette 1.

[0065] Even with such a configuration, by the engagement of the engaging arm 42 and the boss member 41, the pulling - in action of the feeding cassette 1 and the positioning action of the feeding cassette 1 regarding the attachment / detachment direction Y can be obtained. Also, since the engaging arm 42 that can swing in a direction intersecting the attachment / detachment direction Y absorbs the variation in the positional relationship between members due to component tolerances, assembly tolerances, etc., deformation and breakage of the members are reduced. In addition, the possibility of creep deformation of the engaging member due to the biasing force of the biasing member can be reduced.

[0066] (Modification example) In Examples 1 and 2, the column - shaped boss member 41 was exemplified as the engaged member. However, for example, a polygonal - shaped or spindle - shaped engaged member when viewed from above may be used. That is, any shape can be used that has a locked portion on the upstream side in the mounting direction Y2 and a portion on the downstream side of the locked portion in the mounting direction Y2, the width of which in the direction perpendicular to the mounting direction Y2 is narrower than that of the locked portion. Also, the engaging member only needs to be able to receive the locked portion into the locking portion using elasticity and generate a mechanical holding force that restricts the locked portion from coming out after acceptance, and is not limited to the shape shown in FIG. 3(a) etc.

[0067] In Examples 1 and 2, the substantially columnar positioning shafts 31 and 34 extending in the mounting direction Y2 of the supply cassette 1 are illustrated as the to-be-positioned parts. However, a multi-sided columnar shape or a flat plate-shaped member extending so as to intersect the left-right direction X may be used as the to-be-positioned part. In this case, the positioning part may be changed to an appropriate shape that can regulate the displacement in the left-right direction X of the supply cassette 1 according to the shape of the to-be-positioned part. Further, the positioning shafts 31 and 34 may be arranged on the printer main body 201A, and the bearing parts 32 and 35 may be arranged on the supply cassette 1.

[0068] (Other Embodiments) In the above-described embodiment, the sheet feeding device provided as a part of the printer 201 as an image forming apparatus has been described. However, the present technology may be applied to, for example, a sheet feeding device (option feeder) used by being connected to a printer. In that case, the apparatus main body refers to the apparatus main body of a sheet feeding device different from the printer main body (the part excluding the sheet storage part).

Explanation of Reference Numerals

[0069] 1: Sheet storage part (supply cassette) / 31: To-be-positioned part, first to-be-positioned part (positioning shaft) / 32: Positioning part, first positioning part (bearing hole) / 34: Second to-be-positioned part (positioning shaft) / 35: Second positioning part (bearing hole) / 41: To-be-engaged member (boss member) / 42: Engaging member (engaging arm) / 42a: Claw part / 42b: Guide part / 42c: Opening part (narrow part) / 42d: Concave part (locking part) / 45a, 45b: Regulation parts (regulation surfaces) / 230: Sheet feeding device (cassette feeding part) / 201: Image forming apparatus (printer) / 201A: Apparatus main body (printer main body)

Claims

1. A device main body, A sheet storage part that is detachably attached to the device main body and stores a sheet to be fed, A positioning shaft provided on either the device main body or the sheet storage part and extending in the attachment / detachment direction of the sheet storage part with respect to the device main body, A hole part provided on the other of the device main body and the sheet storage part, and having, In a state where the sheet storage part is pulled out, the positioning shaft is not fitted into the hole part, and in a process where the sheet storage part is moved toward the mounting position within the device main body, the positioning shaft is fitted into the hole part. In a state where the sheet storage part is mounted at the mounting position, due to the fitting of the positioning shaft and the hole part, the sheet storage part is positioned in a crossing direction that is perpendicular to the attachment / detachment direction when viewed in the direction of gravity. A sheet feeding device, An engaged member provided on the device main body, An engaging member provided on the sheet storage part, formed of an elastic material, and elastically deformed as the sheet storage part is attached to the device main body. By engaging with the engaged member, the engaging member holds the sheet storage part at the mounting position with respect to the attachment / detachment direction, and further having, The engaging member is swingable in the crossing direction, In a state where the sheet storage part is mounted at the mounting position, the position of the positioning shaft in the crossing direction and the position of the engaging member in the crossing direction are separated, and the positioning shaft and the engaging member are arranged such that the position of the positioning shaft in the attachment / detachment direction and the position of the engaging member in the attachment / detachment direction overlap, A sheet feeding device characterized by this.

2. Further having a mounting member detachably attached to the sheet storage part, The engaging member is detachable from the sheet storage part by attaching and detaching the mounting member, The sheet feeding device according to claim 1, characterized by this.

3. The engaging member swings about the mounting member. The sheet feeding device according to claim 2, characterized in that.

4. The sheet feeding device according to any one of claims 1 to 3, further comprising a biasing member that biases the sheet storage portion in the intersecting direction in a state where the sheet storage portion is mounted at the mounting position.

5. A feed roller that feeds the sheets stacked on the sheet storage portion to one side in the intersecting direction, A separating member that is movable between a contact position that contacts the feed roller to form a nip portion and a separation position that is separated from the feed roller, and separates the sheets conveyed by the feed roller one by one at the nip portion; A pressed member for moving the separating member from the separation position to the contact position by being pressed in the intersecting direction by the sheet storage portion as the sheet storage portion is mounted on the apparatus main body; further comprising: The biasing member biases the pressed member toward the sheet storage portion in the intersecting direction. The sheet feeding device according to claim 4, characterized in that.

6. A pickup roller that is movable between a feeding position that contacts the upper surface of the sheets stacked on the sheet storage portion and feeds them out to one side in the intersecting direction and a retracted position above the feeding position; A pressed member for moving the pickup roller from the retracted position to the feeding position by being pressed in the intersecting direction by the sheet storage portion as the sheet storage portion is mounted on the apparatus main body; further comprising: The biasing member biases the pressed member toward the sheet storage portion in the intersecting direction. The sheet feeding device according to claim 4, characterized in that.

7. The engaging member has a recess for receiving the engaged member in a state where the sheet storage portion is in the mounting position, and a guiding portion for guiding the engaged member toward the recess when the sheet storage portion is mounted on the apparatus main body. The sheet storage portion has a restricting portion for restricting the swing range of the engaging member. The guiding portion is formed so as to guide the engaged member toward the recess in any position within the swing range restricted by the restricting portion. The sheet feeding device according to any one of claims 1 to 6, characterized in that.

8. The engaging member has two claw portions forming the recess, and an opening is formed between the two claw portions, the opening opening toward the downstream side in the mounting direction of the sheet storage portion. The width of the opening in the intersecting direction is narrower than the width of the engaged member in the intersecting direction. The guiding portion is provided at the tips of the two claw portions and is arranged such that the interval in the intersecting direction becomes wider than the width of the engaged member toward the downstream side in the mounting direction. The sheet feeding device according to claim 7, characterized in that.

9. An apparatus main body, A sheet storage portion that is detachably mounted on the apparatus main body and stores the sheet to be fed. A positioning shaft provided on either the apparatus main body or the sheet storage portion and extending in the attaching / detaching direction of the sheet storage portion with respect to the apparatus main body. A hole portion provided on the other of the apparatus main body and the sheet storage portion. In a state where the sheet storage unit is pulled out, the positioning shaft is not fitted into the hole portion, and in a process where the sheet storage unit is moved toward the mounting position in the apparatus main body, the positioning shaft is fitted into the hole portion. In a state where the sheet storage unit is mounted at the mounting position, due to the fitting of the positioning shaft and the hole portion, the sheet storage unit is positioned in a crossing direction that perpendicularly intersects the attachment / detachment direction when viewed in the direction of gravity. The sheet feeding device is as follows: An engaged member provided on the sheet storage unit; An engaging member provided on the apparatus main body, formed of an elastic material, and elastically deformed with the mounting of the sheet storage unit to the apparatus main body to engage with the engaged member. The engaging member holds the sheet storage unit at the mounting position with respect to the attachment / detachment direction. The sheet feeding device further has the engaging member; The engaging member is swingable in the crossing direction; In a state where the sheet storage unit is mounted at the mounting position, the position of the positioning shaft in the crossing direction and the position of the engaging member in the crossing direction are separated, and the positioning shaft and the engaging member are arranged such that the position of the positioning shaft in the attachment / detachment direction and the position of the engaging member in the attachment / detachment direction overlap; A sheet feeding device characterized by the above.

10. A positioning portion provided on the apparatus main body and arranged at a position upstream of the positioning shaft and the hole portion in the mounting direction of the sheet storage unit with respect to the apparatus main body in a state where the sheet storage unit is mounted at the mounting position; A to-be-positioned portion provided on the sheet storage unit and arranged to engage with the positioning portion in a state where the sheet storage unit is mounted at the mounting position, for positioning the sheet storage unit in the crossing direction. The sheet feeding device according to any one of claims 1 to 9 further has the to-be-positioned portion; A sheet feeding device according to any one of claims 1 to 9, characterized by the above.

11. The engaging member has two claw portions; An opening through which the engaged member passes is formed between the two claw portions as the sheet storage portion moves toward the mounting position. The width of the opening in the intersecting direction is narrower than the width of the engaged member in the intersecting direction. The elastic force of the engaging member acts as a force in the mounting direction on the sheet storage portion. The sheet feeding device according to any one of claims 1 to 10, characterized in that.

12. The positioning shaft has a cylindrical portion and a tapered portion provided on the tip side of the positioning shaft with respect to the cylindrical portion and formed so that the outer diameter decreases toward the tip side. In the process of the sheet storage portion moving toward the mounting position, before the engaging member and the engaged member engage, the tapered portion enters the hole portion, and after the widest portion of the engaged member in the intersecting direction passes through the opening of the engaging member, the sheet storage portion is positioned in the intersecting direction by the fitting of the cylindrical portion and the hole portion. The sheet feeding device according to claim 11, characterized in that.

13. A tapered portion is provided at the tip of the positioning shaft and is formed so that the outer diameter decreases toward the tip side of the positioning shaft. In the process of the sheet storage portion moving toward the mounting position, before the engaging member and the engaged member engage, the tapered portion enters the hole portion. The sheet feeding device according to any one of claims 1 to 11, characterized in that.

14. The sheet feeding device according to any one of claims 1 to 13, Image forming means for forming an image on the sheet fed from the sheet feeding device, An image forming apparatus characterized by comprising.

Images