Paper feeder and image forming apparatus

Abstract

To provide a paper feeder capable of appropriately drawing a paper-feeding cassette to an attachment position.SOLUTION: A paper feeder comprises a body part and a paper-feeding cassette. The body part comprises a pull-in device for drawing the paper-feeding cassette to an attachment position, and a support member for supporting the paper-feeding cassette. The paper-feeding cassette comprises a rail part being in contact with an upper portion of the support member. The rail part comprises a first inclination part inclined so as to become high toward a drawing direction of the paper-feeding cassette in an area coming into contact with the support member, while drawing the paper-feeding cassette by the pull-in device.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a paper feeder and an image forming apparatus. [Background technology]

[0002] In an image forming apparatus such as a copying machine, a paper feeder having a paper feed cassette that stores a plurality of sheets of paper in a stack is provided. Patent Document 1 discloses a retraction device for such a paper feeder that automatically retracts the paper feed cassette to a predetermined mounting position when the paper feed cassette is pushed into the device body to a certain extent.

[0003] The retraction device disclosed in Patent Document 1 has a pair of retraction modules each having an engaged portion provided on the left and right rails of the device body, and an engaging portion provided on the left and right sides of the paper feed cassette.

[0004] The retraction device disclosed in Patent Document 1 can retract the paper feed cassette toward the retraction end position when the engaged portion and the engaging portion engage with each other at the retraction start position. This reduces the burden on the user when pushing the paper feed cassette into the device body when inserting the paper feed cassette into the device body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-27991 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above-mentioned Patent Document 1 does not consider the relationship between the magnitude of the load generated when the paper feed cassette is pulled to the installation position and the magnitude of the pulling force of the retraction device, and does not have a configuration that appropriately pulls the paper feed cassette to the specified installation position.

[0007] An object of the present disclosure is to provide a paper feed device that can properly retract a paper feed cassette to an installation position. [Means for solving the problem]

[0008] A paper feeding device according to one embodiment of the present disclosure includes a main body portion and a paper feeding cassette that is capable of being inserted and pulled out in a first direction relative to the main body portion, wherein the main body portion includes a retraction device that retracts the paper feeding cassette to an installation position and a support member that supports the paper feeding cassette, and the paper feeding cassette has a rail portion extending in the first direction and abutting on the support member, and the rail portion has a first inclined portion that is inclined so as to become higher toward the pull-out direction of the paper feeding cassette in the area where it abuts against the support member while the paper feeding cassette is retracted by the retraction device.

[0009] An image forming apparatus according to one embodiment of the present disclosure is a paper feeding device having a main body section and a paper feed cassette arranged to be insertable and removable in a first direction relative to the main body section, wherein the main body section has a retraction device that retracts the paper feed cassette to an installation position and a support member that supports the paper feed cassette, the paper feed cassette having a rail section extending in the first direction and abutting on the support member, the rail section having a first inclined section that is inclined so as to become higher toward the removal direction of the paper feed cassette in an area where the rail section abuts against the support member while the paper feed cassette is retracted by the retraction device, and an image forming section that forms an image on paper sent out from the paper feed device. Effect of the Invention

[0010] According to the present disclosure, the paper feed device has an advantage of being able to appropriately retract the paper feed cassette to the mounting position. [Brief description of the drawings]

[0011] [Figure 1]1 is a schematic diagram illustrating an internal structure of an image forming apparatus according to an embodiment, as viewed from the front side. [Diagram 2] FIG. 1 is a perspective view showing a paper feed device according to an embodiment. [Diagram 3] 3 is a plan view of a paper feed cassette included in the paper feed device shown in FIG. 2, seen from above. [Figure 4] 3 is a side view of a paper feed cassette included in the paper feed device shown in FIG. 2, seen from the right side. [Diagram 5] 3 is a perspective view showing an internal structure of a sheet feeding device main body part included in the sheet feeding device shown in FIG. 2. [Figure 6] 4 is a perspective view showing a first boss hole formed in a sheet feeding device main body. FIG. [Figure 7] 4 is a plan view showing an internal structure of a pull-in unit included in the sheet feeding device main body according to the embodiment; FIG. [Figure 8] 4 is a plan view showing an internal structure of a pull-in unit included in the sheet feeding device main body according to the embodiment; FIG. [Figure 9] 10 is a graph showing a relationship between a pulling force of a pulling unit and a force required to pull a paper feed cassette to an installation position in a paper feed device according to a comparative example of an embodiment. [Figure 10] 5 is a partial enlarged view of an area A of the paper feed cassette shown in FIG. 4. [Figure 11] 11 is a diagram showing a schematic diagram of a height difference of rail portions of the paper feed cassette shown in FIG. 10. FIG. [Figure 12] 10 is a graph showing the relationship between the pulling force of a pulling unit and the force required to pull a paper feed cassette to an installation position in a paper feed device according to an embodiment. [Figure 13] 10A and 10B are diagrams illustrating a principle of generation of a force that draws a paper feed cassette included in a paper feed device according to an embodiment to a mounting position. [Figure 14] 10A and 10B are diagrams illustrating a height difference between rail portions of a sheet feed cassette according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The embodiments and modifications of the present disclosure will be described with reference to the drawings. In the following, the same or corresponding elements are given the same reference numerals throughout all the drawings, and their repeated description will be omitted. In addition, the embodiments and modifications described below are merely examples of the present disclosure, and the present disclosure is not limited to the embodiments and modifications. Even if the embodiments and modifications are not limited to the embodiments and modifications, various modifications can be made according to the design, etc., as long as they do not deviate from the technical idea of ​​the present disclosure.

[0013] [Image forming device] An image forming apparatus 100 according to an embodiment will be described with reference to FIG. 1. FIG. 1 is a schematic diagram showing the internal structure of the image forming apparatus 100 according to an embodiment as viewed from the front side. In the image forming apparatus 100, the left side of the horizontal direction as viewed from the front side is defined as the left direction, and the right side is defined as the right direction. In addition, in the depth direction as viewed from the front side, the front side (near side) of the image forming apparatus 100 is defined as the front direction, and the back side (rear side) is defined as the rear direction. In the image forming apparatus 100, the bottom side is defined as the downward direction, and the opposite side is defined as the upward direction.

[0014] The image forming apparatus 100 according to the embodiment is a color image forming apparatus that forms multi-color and monochrome images on a sheet P such as a recording paper. The image forming apparatus 100 forms an image on the sheet P based on image data read by an image reading apparatus 200 or image data received from an external source. Note that the image forming apparatus 100 may be a monochrome image forming apparatus.

[0015] As shown in FIG. 1, the image forming apparatus 100 includes a main body 110, an image reading device 200, a paper feeding device 400, and a manual feeding unit 510. The main body 110 includes an image reading device 200, a paper feeding device 400, and a manual feeding unit 510.

[0016] An image reading device 200 is provided on the upper part of the main body 110. The image reading device 200 is a device that reads an image of an original G. The image reading device 200 includes an original placement table 221 formed of a transparent material on which an original G is placed. An original pressing cover 218 is provided above the original placement table 221 and is attached so as to be freely opened and closed via a hinge or the like. An original supply tray 220 is provided on the upper surface of the original pressing cover 218, and an automatic document feeder (ADF: Auto Document Feeder) (not shown) is provided inside the original supply tray 220. The ADF automatically supplies the original G placed on the original supply tray 220 to an image reading position 222 one by one.

[0017] The image reading device 200 includes an image reading unit 226 that reads an image from an original G. The image reading unit 226 includes a light source, a plurality of mirrors, an imaging lens, and a line sensor, all of which are not shown. The image reading device 200 exposes the original G to light emitted from the light source, and guides the reflected light from the original G to the imaging lens by the plurality of mirrors. The imaging lens then forms an image of the reflected light on a light receiving element of the line sensor. The line sensor detects the luminance or chromaticity of the reflected light that has formed an image on the light receiving element, and generates image data based on the original G. For example, a CCD (Charge Coupled Device) or a CIS (Contact Image Sensor) can be used as the line sensor.

[0018] A sheet feeding device 400 including a sheet feeding cassette 410 and a sheet supply unit 420 is provided at the bottom of the main body unit 110 .

[0019] The sheet feed cassette 410 stores sheets P to be supplied to the main body 110. In the image forming apparatus 100 according to the present embodiment, the sheet feed cassette 410 is configured to store 500 sheets P. The sheets P stored in the sheet feed cassette 410 are supplied to the main body 110 by the sheet supply unit 420.

[0020] That is, the sheet supply unit 420 has a pickup roller 421, a supply roller 422, and a separation roller 423. The pickup roller 421 rotates to pull out the sheet P stored in the paper feed cassette 410 from above and send it toward the supply roller 422 and the separation roller 423. The separation roller 423 is disposed at a position facing the supply roller 422. When the sheet P is supplied to the main body unit 110, the separation roller 423 is maintained in a state of pressing the supply roller 422. Then, the separation roller 423 rotates to separate and transport the sheet P one by one between the supply roller 422 and the separation roller. Note that the pickup roller 421 may not be provided, and the supply roller 422 may also function as the pickup roller 421. In this configuration, the supply roller 422 rotates to pull out the sheet P from the paper feed cassette 410.

[0021] 1, for convenience of explanation, only one paper feed cassette 410 and one sheet supply unit 420 are shown, but the image forming apparatus 100 according to the embodiment has three paper feed cassettes 410 arranged in multiple stages in the vertical direction, and each paper feed cassette 410 is provided with a sheet supply unit 420. The detailed configuration of the paper feed device 400 will be described later.

[0022] Further, a manual feed unit 510 having a sheet storage portion is provided on the lower right side of the main body portion 110. The manual feed unit 510 supplies the sheet P that cannot be set in the sheet feed cassette 410 of the sheet feed device 400 to the image forming apparatus 100.

[0023] The sheets P accommodated in the sheet cassette 410 of the sheet feeding device 400 and the sheets P accommodated in the sheet accommodation section of the manual feeding unit 510 are sent to the sheet conveying path W1 of the main body 110 through the conveying rollers 12a.

[0024] The main body section 110 includes an image forming section 102 and a sheet transport system 103 .

[0025] The image forming section 102 includes an exposure unit 1, a developing unit 2, a photoconductor drum 3 acting as an electrostatic latent image carrier, a cleaning section 4, a charging device 5, a primary transfer device 6, a fixing unit 7, and a secondary transfer device 10. The image forming section 102 forms an image on a sheet P conveyed from a paper feed cassette 410 or the like, and discharges the sheet onto a discharge tray 14. Examples of image data for forming an image on the sheet P include image data read from an original G by an image reading section 226, and image data transmitted from an external computer or the like.

[0026] On the other hand, the sheet transport system 103 includes a sheet transport path W1. In the sheet transport path W1, there are arranged, from the transport roller 12a toward the discharge tray 14, the registration roller 13, the transfer roller 10a of the secondary transfer device 10, the fixing roller 71 and the pressure roller 72 of the fixing unit 7, and the discharge roller 31. The direction from the transport roller 12a toward the discharge tray 14 is referred to as the sheet transport direction.

[0027] When an image is formed in the image forming apparatus 100, in the image forming section 102, the charging device 5 uniformly charges the surface of the photoconductor drum 3. Furthermore, the exposure unit 1 exposes the charged surface of the photoconductor drum 3 to a laser based on image data. This forms an electrostatic latent image on the photoconductor drum 3. The exposure unit 1 can be configured as a laser scanning unit (LSU) equipped with a laser emission section, a reflection mirror, and the like (not shown).

[0028] The electrostatic latent image formed on the photosensitive drum 3 is developed by the developing unit 2 and visualized into a toner image. That is, the developing unit 2 includes a developing tank that contains toner and a developing roller that functions as a developer carrier, both not shown. The developing unit 2 supplies toner to the surface of the photosensitive drum 3, and visualizes the electrostatic latent image formed on the surface of the photosensitive drum 3 with the toner. A toner concentration detection sensor (not shown) that detects the toner concentration is provided inside the developing tank. When the toner concentration detected by the toner concentration detection sensor becomes lower than a predetermined value, toner is replenished to the developing tank from a toner replenishing device (not shown).

[0029] The toner image on the photosensitive drum 3 is transferred in the primary transfer device 6 onto an intermediate transfer belt 6c that is stretched between a drive roller 6a and a driven roller 6b and rotates along a rotation direction E. The toner image on the intermediate transfer belt 6c is then transported to a secondary transfer device 10.

[0030] Meanwhile, sheet P supplied from sheet feeder 400 or manual feed unit 510 is conveyed through sheet conveying path W1, via conveying rollers 12a, to registration rollers 13. Next, sheet P is conveyed by registration rollers 13 to transfer rollers 10a at a timing when sheet P and the toner image on photosensitive drum 3 are aligned. Then, the toner on photosensitive drum 3 is transferred onto sheet P by transfer roller 10a. Thereafter, sheet P passes through fixing roller 71 and pressure roller 72 in fixing unit 7, and is discharged to discharge tray 14 via discharge rollers 31.

[0031] The fixing unit 7 includes a fixing roller 71 and a pressure roller 72, and is disposed downstream of the image forming section 102 in the sheet conveying direction. The fixing roller 71 is set to a predetermined fixing temperature (for example, 160° C.), and the toner image transferred to the sheet P is melted, mixed, and pressed against the sheet P as the sheet P passes through a nip area (fixing nip portion) between the fixing roller 71 and the pressure roller 72. In this manner, the toner image is thermally fixed to the sheet P.

[0032] When an image is formed on the back side of the sheet P in addition to the front side, the sheet P is transported in the opposite direction from the discharge rollers 31 through the reverse sheet transport path W2. In the reverse sheet transport path W2, the sheet P passes through the reverse transport rollers 12b provided at two positions with a predetermined interval between them, and is guided again to the registration rollers 13 in a state where the sheet P is turned over. Then, in the same manner as the front side of the sheet P, a toner image is formed and fixed on the back side of the sheet P. The sheet P is then discharged to the discharge tray 14.

[0033] After development and image transfer, toner remains on the surface of the photoconductor drum 36. Therefore, the image forming apparatus 100 is provided with a cleaning unit 4 having a cleaning blade or the like that contacts the surface of the photoconductor drum 36, and is configured to remove the toner remaining on the surface of the photoconductor drum 36 by the cleaning unit 4.

[0034] Moreover, the main body 110 having the above-mentioned configuration is provided with a control unit including a CPU, a memory, etc. (not shown). The control unit is configured to transmit control signals to each part of the image forming apparatus 100 in response to input operations on an operation panel, etc., and to cause the image forming apparatus 100 to execute various operations.

[0035] Incidentally, image forming apparatus 100 is configured to include sheet feeding device 400 and manual feed unit 510. However, image forming apparatus 100 may be configured to include an external sheet feeding device, and to feed sheet P from this external sheet feeding device to sheet transport path W1.

[0036] (Paper Feeding Device) 2 to 5, the configuration of the sheet feeding device 400 according to the embodiment will be described. As the sheet feeding device 400 according to the embodiment, a sheet feeding device built into the lower part of the image forming apparatus 100 will be described as an example, but the present invention is not limited to this. For example, the sheet feeding device 400 may be provided separately from the image forming apparatus 100.

[0037] Fig. 2 is a perspective view showing a sheet feeding device 400 according to an embodiment. Fig. 3 is a plan view of a sheet feeding cassette 410 provided in the sheet feeding device 400 shown in Fig. 2, seen from above. Fig. 4 is a side view of a sheet feeding cassette 410 provided in the sheet feeding device 400 shown in Fig. 2, seen from the right side. Fig. 5 is a perspective view showing an internal structure of a sheet feeding device main body 401 provided in the sheet feeding device 400 shown in Fig. 2.

[0038] FIG. 2 is a perspective view of the sheet feeding device 400 as viewed from the front side, and in the horizontal direction as viewed from the front side, the left side is defined as the left direction, and the right side is defined as the right direction. In addition, in the depth direction as viewed from the front side, the front side (near side) of the sheet feeding device 400 is defined as the front direction, and the back side (deep side) is defined as the rear direction. In addition, in the sheet feeding device 400, the bottom side is defined as the downward direction, and the opposite side is defined as the upward direction. Note that FIG. 2 shows a state in which the sheet feeding cassette 410 is pulled out from the sheet feeding device main body 401. Also, in FIG. 5, the left and right side walls of the sheet feeding device 400 are omitted for convenience in order to make it easier to understand the internal structure of the sheet feeding device main body 401.

[0039] 2, sheet feeding device 400 has a substantially rectangular parallelepiped shape, and includes sheet feeding device main body 401 (main body) and three sheet feeding cassettes 410. Each of the three sheet feeding cassettes 410 is provided so as to be removable (insertable and removable) in the front-to-rear direction (first direction) relative to sheet feeding device main body 401. Note that in the front-to-rear direction, the direction in which sheet feeding cassette 410 is inserted into sheet feeding device main body 401 is referred to as the insertion direction, and the direction in which sheet feeding cassette 410 is removed from sheet feeding device main body 401 is referred to as the removal direction of sheet feeding cassette 410.

[0040] (Paper feed cassette) As shown in Figures 2 and 3, the paper feed cassette 410 includes a rectangular bottom 410a, and a first cassette wall 410b, a second cassette wall 410c, a third cassette wall 410d (second side wall), and a fourth cassette wall 410e (first side wall) that are erected upward from the bottom 410a along the outer periphery of the bottom 410a.

[0041] The first cassette wall 410b is connected to the front edge of the bottom 410a, the second cassette wall 410c is connected to the rear edge of the bottom 410a, the third cassette wall 410d is connected to the left edge of the bottom 410a, and the fourth cassette wall 410e is connected to the right edge of the bottom 410a, and the bottom 410a, the first cassette wall 410b, the second cassette wall 410c, the third cassette wall 410d, and the fourth cassette wall 410e form a rectangular parallelepiped container with an open top.

[0042] A plurality of sheets P are placed at predetermined positions in a sheet storage area surrounded by the bottom 410a, the first cassette wall 410b, the second cassette wall 410c, the third cassette wall 410d, and the fourth cassette wall 410e. For convenience of explanation, the sheets P are omitted in FIG. 3.

[0043] The sheet storage area is provided with a first guide clip 411a and a second guide clip 411b for aligning a plurality of sheets P at a predetermined position. Each of the first guide clip 411a and the second guide clip 411b has a partition plate standing upward from the bottom 410a. The partition plate of the first guide clip 411a is movable in the left-right direction, and is moved to abut against the left side of the sheet P. The partition plate of the second guide clip 411b is movable in the front-rear direction (first direction), and is moved to abut against the front side of the sheet P. In this way, the partition plate of the first guide clip 411a and the partition plate of the second guide clip 411b allow a plurality of sheets P to be placed in an aligned state at a predetermined position in the sheet storage area.

[0044] In the embodiment of the present disclosure, as described below, when sheet feed cassette 410 is inserted into sheet feeder main body 401, sheet supply unit 420 is provided at a position corresponding to the right side of sheet feed cassette 410 of sheet feeder main body 401. Therefore, when sheet feed cassette 410 is viewed in a plan view, sheets P are placed to the right of the center position in the left-right direction of sheet feed cassette 410. Therefore, at bottom 410a of sheet feed cassette 410, the center of gravity of sheet feed cassette 410 is located to the right of the center position in the left-right direction.

[0045] As shown in FIG. 2 to FIG. 4, a pair of rails 412 that abut against the sheet feeding device main body 401 are provided on both left and right sides of the sheet feeding cassette 410, i.e., on the outer surface of each of the third cassette wall 410d and the fourth cassette wall 410e. The rails 412 provided on the third cassette wall 410d are flange members that protrude leftward from the third cassette wall 410d and extend in the front-rear direction. The rails 412 provided on the fourth cassette wall 410e are flange members that protrude rightward from the fourth cassette wall 410e and extend in the front-rear direction. As shown in FIG. 4, the rails 412 provided on the fourth cassette wall 410e are provided with a protrusion 415 that engages with a retracting unit 500 (described later) at a substantially middle position of the rails 412.

[0046] 4, for example, a roller 416 for a paper feed cassette is provided at the rear position of each of the pair of rail portions 412. The roller 416 for a paper feed cassette is a cylindrical rotating member that abuts against the guide frame 403 to facilitate the insertion and removal of the paper feed cassette 410. The roller 416 for a paper feed cassette can assist the movement of the paper feed cassette 410 in the front-rear direction. The rail portion 412 will be described in detail later.

[0047] 3, the first cassette wall 410b of the sheet feed cassette 410 has a first flange 410b1 protruding leftward from a joining position with the third cassette wall 410d, and a second flange 410b2 protruding rightward from a joining position with the fourth cassette wall 410e. The second flange 410b2 is provided with a first boss 413 (protruding portion) which is a rod-shaped member protruding toward the rear (insertion direction).

[0048] Further, the second cassette wall portion 410c is provided with a second boss 414 (protruding portion) which is a rod-shaped member protruding rearward near the joining position with the fourth cassette wall portion 410e.

[0049] As will be described later, the sheet feeding device main body 401 is provided with a first boss hole 406 (hole) through which the first boss 413 is inserted, and a second boss hole 407 (hole) through which the second boss 414 is inserted. Then, by inserting the first boss 413 into the first boss hole 406 and inserting the second boss 414 into the second boss hole 407, the sheet feeding cassette 410 can be aligned within the sheet feeding device main body 401.

[0050] A handle 417 is provided to protrude forward from approximately the center of first cassette wall 410b of sheet feed cassette 410. A user can insert sheet feed cassette 410 into sheet feeder main body 401 or pull sheet feed cassette 410 out of sheet feeder main body 401 by holding handle 417.

[0051] (Paper feeder main body) 2 and 5, the sheet feeding device main body 401 has a generally rectangular parallelepiped shape with an open top and front. When the sheet feeding device 400 is provided separately from the image forming device 100, the top may be closed by an upper wall.

[0052] The sheet feeder main body 401 includes a rectangular sheet feeder bottom 401a, a rear wall 401b, a left wall 401c, and a right wall 401d that stand upward from the sheet feeder bottom 401a along the outer periphery of the sheet feeder bottom 401a. The rear wall 401b is connected to the rear edge of the sheet feeder bottom 401a, the left wall 401c is connected to the left edge of the sheet feeder bottom 401a, and the right wall 401d is connected to the right edge of the sheet feeder bottom 401a, so that the sheet feeder bottom 401a, the rear wall 401b, the left wall 401c, and the right wall 401d form a substantially rectangular parallelepiped housing whose top and front are open. The paper feed cassette 410 is configured so that it can be inserted into the paper feed device main body 401 and pulled out from the inside of the paper feed device main body 401 through an opening on the front side.

[0053] 2, the sheet supply unit 420 is provided on the right side wall 401d of the sheet feeder main body 401. Therefore, as described above, the sheet storage area in the sheet feed cassette 410 where the sheets P are placed is located to the right of the center of the sheet feed cassette 410.

[0054] 5, the above-mentioned first boss hole 406 is formed in the right frame side of the frame 402 that forms an opening in the front of the sheet feeding device main body 401. Also, the above-mentioned second boss hole 407 is formed in the rear wall 401b. In this embodiment, the sheet feeding device 400 is provided with three sheet feeding cassettes 410. Therefore, the first boss hole 406 and the second boss hole 407 are formed at positions corresponding to each sheet feeding cassette 410.

[0055] As shown in Fig. 6, the inner surface of first boss hole 406 is formed with uneven portion 406a consisting of a plurality of projections and recesses. Fig. 6 is a perspective view showing first boss hole 406 formed in sheet feeding device main body 401. As shown in Fig. 6, first boss hole 406 has uneven portions 406a provided on parts of the left and right side walls of the inner periphery of first boss hole 406.

[0056] In this way, first boss hole 406 has uneven portion 406a on its inner periphery, which reduces the contact area between first boss hole 406 and first boss 413. This reduces the load when first boss 413 is inserted into first boss hole 406.

[0057] Although not shown, second boss hole 407 has an uneven portion formed on its inner surface, similar to first boss hole 406. This makes it possible to reduce the contact area between second boss hole 407 and second boss 414, and also reduces the load when second boss 414 is inserted into second boss hole 407.

[0058] 5, a pair of guide frames 403 are provided on the inside of the left side wall 401c and the right side wall 401d of the sheet feeding device main body 401, extending in the front-rear direction (first direction) and capable of guiding the sheet feeding cassette 410 inserted into the sheet feeding device main body 401 to an attachment position. Note that the attachment position is a predetermined position when the sheet feeding cassette 410 is attached to the sheet feeding device main body 401. When the sheet feeding cassette 410 is in the attachment position, the sheets P accommodated in the sheet feeding cassette 410 are in a predetermined sheet feeding position.

[0059] The pair of guide frames 403 are rod members extending in the front-rear direction and arranged so as to span between the left and right frame sides of the frame body 402 and the rear wall portion 401b. As shown in Fig. 5, the cross section of the guide frame 403 is U-shaped, and a sliding surface 403a along which the sheet feed cassette rollers 416 move is formed below. The sliding surface 403a supports the sheet feed cassette 410 from below and allows the sheet feed cassette 410 to move in the front-rear direction.

[0060] Further, a retraction unit 500 (retraction device) is provided on an upper surface 403b of the right guide frame 403 of the pair of guide frames 403. Note that in this embodiment, the retraction unit 500 is configured to be provided on the sheet feeding device main body 401 via the guide frame 403, but is not limited to this configuration. For example, the retraction unit 500 may be configured to be provided directly on the inside of the right side wall 401d of the sheet feeding device main body 401.

[0061] The retraction unit 500 engages with the sheet feed cassette 410 inserted into the sheet feeder main body 401 and applies a force to pull it toward the rear, i.e., the insertion direction. This allows the retraction unit 500 to retract the sheet feed cassette 410 to the mounting position. This reduces the burden on the user of pushing the sheet feed cassette 410 into the sheet feeder main body 401 when inserting the sheet feed cassette 410 into the sheet feeder main body 401. The retraction unit 500 will be described in detail later.

[0062] Further, rollers 405 (support members) are provided on the front end portions (end portions in the pull-out direction of the paper feed cassette 410) of the sliding surfaces 403a of the pair of guide frames 403. The rollers 405 are rotating bodies that rotate so that the paper feed cassette 410 can move relatively in the front-to-rear direction with respect to the guide frames 403. The rollers 405 rotate about an axis that extends in a horizontal direction perpendicular to the front-to-rear direction. Therefore, the rail portions 412 come into contact with the rollers 405 to assist the movement of the paper feed cassette 410 in the front-to-rear direction. Therefore, the rollers 405 can facilitate the insertion and removal of the paper feed cassette 410.

[0063] In addition, in the paper feeder main body 401, the rollers 405 are provided at the front end of the guide frame 403, but the position at which the rollers 405 are provided is not limited to this. The rollers 405 may be rotatably provided on a member separate from the guide frame 403, for example, at a position adjacent to the front end of the guide frame 403 in the front-rear direction.

[0064] As shown in FIG. 2, a switching lever 409 is provided at the bottom of the sheet supply unit 420 and above the rear side of the right guide frame 403. The switching lever 409 is a member for switching between a pressing state in which the separation roller 423 is pressed against the supply roller 422 and a release state in which the pressing state is released. The switching lever 409 is provided so as to be swingable in the horizontal direction. That is, when the sheet feed cassette 410 is inserted into the sheet feed device main body 401 and the sheet feed cassette 410 abuts against the switching lever 409, the switching lever 409 moves from the initial position toward the rear side. In this way, when the switching lever 409 moves toward the rear side, the separation roller 423 presses the supply roller 422. On the other hand, when the sheet feed cassette 410 is pulled out of the sheet feed device main body 401 and the sheet feed cassette 410 is separated from the swinging member 424, the swinging member 424 moves forward and returns to the initial position. In this manner, when the swinging member 424 returns to the initial position, the pressing state of the separation roller 423 against the supply roller 422 is released.

[0065] 2, a size detection switch 408 that detects the size of the sheet P is provided on the rear wall 401b of the sheet feeding device main body 401. The size detection switch 408 has a plurality of detection portions that protrude forward from the rear wall 401b. The size detection switch 408 can detect the size of the sheet P when the sheet P abuts against these detection portions.

[0066] (Retraction unit) Next, the retraction unit 500 will be described with reference to Fig. 7 and Fig. 8. Fig. 7 and Fig. 8 are plan views showing the internal structure of the retraction unit 500 provided in the sheet feeding device main body 401 according to the embodiment. Fig. 7 shows the state when the engagement part 505 of the retraction unit 500 is positioned at the rearmost side, and Fig. 8 shows the state when the engagement part 505 of the retraction unit 500 is positioned at the frontmost side.

[0067] 7 and 8, retraction unit 500 includes damper section 501, spring 502, and housing 503 that houses damper section 501 and spring 502. Damper section 501 is configured such that a piston (not shown) reciprocates in the front-rear direction in a case filled with a fluid (e.g., oil). Damper section 501 includes rod 504 that extends in the front-rear direction and protrudes from the front end of the case. Rod 504 extends in the front-rear direction, and when the end on the case side is the base end and the end opposite the base end is the tip, engagement section 505 is provided at the tip, and the base end is joined to the piston.

[0068] Spring 502 is, for example, a coil spring, and has a rear end fixed inside housing 503 and a front end connected to a tip of rod 504. The tip of rod 504 is configured to move forward and backward in the front-rear direction relative to the case of damper section 501. Therefore, spring 502 fixed to the tip of rod 504 expands and contracts in response to the forward and backward movement of rod 504.

[0069] The engagement portion 505 includes a first contact portion 505a that contacts the protrusion 415 of the sheet feed cassette 410 when the sheet feed cassette 410 is inserted into the sheet feed device main body 401, and a second contact portion 505b that contacts the protrusion 415 of the sheet feed cassette 410 when the sheet feed cassette 410 is pulled out from inside the sheet feed device main body 401 to the outside. The first contact portion 505a and the second contact portion 505b are provided so as to protrude from the left side of the housing 503.

[0070] Engagement portion 505 further includes first guide shaft 505c and second guide shaft 505d that engage with guide grooves 506 formed on the upper and lower surfaces of housing 503. First guide shaft 505c is provided on the front side of engagement portion 505, and second guide shaft 505d is provided on the rear side of engagement portion 505. First guide shaft 505c and second guide shaft 505d are configured to move along guide groove 506. Therefore, the movement of engagement portion 505 is regulated by guide groove 506.

[0071] Guide groove 506 is an approximately L-shaped slit that extends along the left side of housing 503 from approximately the middle position of housing 503 toward the front and then bends toward the right near the front end of housing 503.

[0072] 7 and 8, when the engaging portion 505 moves from the rear side to the front side, the engaging portion 505 moves along the left side of the housing 503. Then, the first guide shaft 505c moves toward the right side of the housing 503 along the guide groove 506 near the front end of the housing 503, and draws the second abutment portion 505b into the housing 503. Then, the first guide shaft 505c is stopped at the end of the guide groove 506.

[0073] As a result, second contact portion 505b of engagement portion 505 is accommodated within housing 503 at the front end portion of housing 503, and engagement between protrusion 415 of paper feed cassette 410 and engagement portion 505 is released.

[0074] Specifically, when paper feed cassette 410 is pulled out from inside paper feed device main body 401 to the outside, protrusion 415 of paper feed cassette 410 abuts and engages with second abutment portion 505b. Then, the force applied by the user to pull out paper feed cassette 410 moves engagement portion 505, which is engaged with protrusion 415, forward. At this time, the tip of rod 504 moves forward, and spring 502 expands forward.

[0075] When the engaging portion 505 moves close to the tip of the retracting unit 500, the second contact portion 505b is housed in the housing 503 as described above, and the engagement between the protrusion 415 and the second contact portion 505b is released. Therefore, the sheet feeding cassette 410 moves forward away from the retracting unit 500, and the sheet feeding cassette 410 is pulled out from inside the sheet feeding device main body 401 to the outside.

[0076] On the other hand, when the sheet cassette 410 is inserted into the sheet feeding device main body 401, the second contact portion 505b of the retraction unit 500 is housed in the housing 503, so that the protrusion 415 of the sheet cassette 410 contacts and engages with the first contact portion 505a without being hindered by the second contact portion 505b. Then, when the protrusion 415 presses the first contact portion 505a backward due to a force applied by the user to push in the sheet cassette 410, the first guide shaft 505c is released from the lock by this force.

[0077] When the first guide shaft 505c is released from the locked state, the restoring force of the stretched spring 502 moves the engaging portion 505 from the front side to the rear side, i.e., in the insertion direction. When the engaging portion 505 moves in this manner, the second contact portion 505b presses the protrusion 415 in the insertion direction. The pressing force from the second contact portion 505b pushes the protrusion 415 in the insertion direction, and as a result, the sheet feeding cassette 410 is drawn into the sheet feeding device main body 401. In this manner, the sheet feeding cassette 410 is drawn into the sheet feeding device main body 401 mainly by the restoring force of the spring 502.

[0078] Therefore, when the user pushes the sheet feed cassette 410 into the position where the protrusion 415 abuts against the first abutment portion 505a, the sheet feed cassette 410 is then drawn into the sheet feeder main body 401 by the drawing unit 500. This reduces the burden on the user when inserting the sheet feed cassette 410 into the sheet feeder main body 401.

[0079] Incidentally, when inserting the sheet feed cassette 410 into the sheet feeder main body 401, various loads exert forces in a direction that hinders the movement of the sheet feed cassette 410. For example, such loads include the above-mentioned switching lever 409 and size detection switch 408. Furthermore, such loads include a coupling mechanism that couples with a lift-up shaft in a lift-up mechanism that raises and lowers the sheets P stored in the sheet feed cassette 410 to a predetermined sheet feed opening height.

[0080] As described above, the retraction unit 500 is configured to retract the sheet feed cassette 410 to the installation position by utilizing the restoring force of the spring 502. Therefore, the magnitude of the force with which the retraction unit 500 retracts the sheet feed cassette 410 decreases as the sheet feed cassette 410 approaches the installation position.

[0081] Therefore, in order to reliably move the paper feed cassette 410 to the installation position using the retraction unit 500, it is necessary to take into consideration the magnitude of the force with which the retraction unit 500 retracts the paper feed cassette 410 and the effect of the load generated when the paper feed cassette 410 moves.

[0082] Here, a comparative paper feeding device having a configuration similar to that of the paper feeding device 400 of this embodiment was prepared, and the relationship between the retraction force of the paper feeding cassette by the retraction unit and the force required to move the paper feeding cassette to the installation position was examined.

[0083] The sheet feeding device according to the comparative example has a similar configuration to sheet feeding device 400 according to the embodiment, except that the shape of the rail portion of the sheet feeding cassette is different. That is, in the sheet feeding device according to the comparative example, the rail portion is provided so as to extend at the same height from the front end to the rear end of the sheet feeding cassette.

[0084] As shown in Fig. 9, in the paper feeder according to the comparative example, the retraction force for retracting the paper feed cassette to the mounting position by the retraction unit may be smaller than the force required to retract the paper feed cassette to the mounting position due to the influence of a load, etc. Fig. 9 is a graph showing the relationship between the retraction force of the retraction unit and the force required to retract the paper feed cassette to the mounting position in the paper feeder according to the comparative example of the embodiment. In Fig. 9, the change in the magnitude of the retraction force of the retraction unit of the paper feeder according to the comparative example is shown by a solid line, and the change in the magnitude of the force required to retract the paper feed cassette to the mounting position is shown by a dashed line.

[0085] Hereinafter, the pulling force of the pulling unit is referred to as a first force, and the force required to pull the paper feed cassette to the mounting position is referred to as a second force.

[0086] In FIG. 9, the horizontal axis indicates the distance between the mounting position of the paper feed cassette provided in the paper feed device according to the comparative example and the paper feed cassette. In other words, the position of the rear wall when the paper feed cassette is in the mounting position is set to 0 mm. The horizontal axis indicates the distance the rear wall is away from the mounting position. Meanwhile, the vertical axis indicates the magnitude of each of the first force and the second force. Note that FIG. 9 shows the changes in the first force and the second force when the distance between the rear wall and the mounting position is in the range of 0 mm to 50 mm. Note that the graph showing the change in the second force in FIG. 9 was obtained by measuring when 500 A3 size sheets were stored in the paper feed cassette (the maximum paper size and maximum number that can be stored).

[0087] As shown in FIG. 9, the first force in the comparative example becomes smaller as it approaches the mounting position. In other words, the restoring force of the spring of the retraction unit becomes smaller as the paper feed cassette approaches the mounting position. On the other hand, the magnitude of the second force in the comparative example does not exceed the magnitude of the first force until the distance between the paper feed cassette and the mounting position is about 7 mm, and gradually becomes smaller like the first force. The reason why the magnitude of the second force becomes smaller is that when the position where the rail part and the roller provided on the guide frame contact each other is set as a fulcrum, the relative positional relationship between the rail part and the fulcrum changes. In other words, as the paper feed cassette moves toward the mounting position, the distance from the fulcrum to the rear end of the paper feed cassette gradually becomes longer. Therefore, as the paper feed cassette moves toward the mounting position according to the principle of leverage, the force required to support the paper feed cassette approximately horizontally becomes smaller.

[0088] However, when the distance between the paper feed cassette and the mounting position is about 6 mm, the magnitude of the second force exceeds the magnitude of the first force due to the influence of the various loads as described above. Thus, when the magnitude of the first force is smaller than the magnitude of the second force in the paper feed device, the paper feed cassette may not be retracted to the mounting position by the retraction unit and may not be properly positioned at the mounting position.

[0089] In order to reliably position the paper feed cassette in the installation position, it is possible to increase the pulling force of the spring in the retraction unit to increase the magnitude of the first force. However, in such a configuration in which the pulling force of the spring is increased, a greater force is required when the user pulls out the paper feed cassette from the paper feed device main body, which increases the burden on the user.

[0090] Therefore, the sheet feeding device 400 according to the embodiment is configured so that the shape of the rail portion 412 of the sheet feeding cassette 410 is devised so that the sheet feeding cassette 410 can be reliably drawn by the drawing unit 500 to the mounting position.

[0091] Specifically, the shape of the contact surface 412a of at least the rail portion 412 provided on the fourth cassette wall portion 410e of the pair of rail portions 412 is devised. The fourth cassette wall portion 410e is a wall portion on the side closer to the center of gravity of the sheet feed cassette 410 when the sheets P are placed thereon in the left-right direction of the sheet feed cassette 410. The contact surface 412b of the rail portion 412 provided on the third cassette wall portion 410d may have the same shape as the contact surface 412a of the rail portion 412 provided on the fourth cassette wall portion 410e. Alternatively, the contact surface 412b of the rail portion 412 provided on the third cassette wall portion 410d may have a shape extending straight in the front-rear direction at a reference height described later.

[0092] The rail portion 412 provided on the fourth cassette wall portion 410e will be described below.

[0093] (Rail section) The configuration of the rail portion 412 provided on the fourth cassette wall portion 410e of the sheet feed cassette 410 included in the sheet feed device 400 according to this embodiment will be described with reference to FIGS.

[0094] Fig. 10 is a partial enlarged view of region A of sheet cassette 410 shown in Fig. 4. Fig. 11 is a diagram showing a schematic diagram of the height difference of rail portion 412 of sheet cassette 410 shown in Fig. 10. Fig. 12 is a graph showing the relationship between the retraction force of retraction unit 500 and the force required to retract sheet cassette 410 to the mounting position in sheet feeding device 400 according to the embodiment. Fig. 13 is a diagram showing a schematic diagram of the principle of generation of the force to retract sheet cassette 410 provided in sheet feeding device 400 according to the embodiment to the mounting position.

[0095] For ease of explanation, first cassette wall 410b and handle 417 are omitted in Fig. 10. In Fig. 11, the horizontal axis indicates the horizontal distance (mm) starting from the front end of rail 412, and the vertical axis indicates the vertical distance (mm) from bottom 410a of sheet cassette 410 to contact surface 412a of rail 412.

[0096] In FIG. 12, the change in the retraction force (first force) of the retraction unit 500 of the sheet feeder 400 is indicated by a solid line, and the change in the force (second force) required to retract the sheet feed cassette 410 to the mounting position is indicated by a dashed line. The horizontal axis of FIG. 12 indicates the distance between the mounting position of the sheet feed cassette 410 provided in the sheet feeder 400 and the sheet feed cassette 410. That is, the position of the second cassette wall 410c when the sheet feed cassette 410 is in the mounting position is set to 0 mm. The horizontal axis indicates how far the second cassette wall 410c is away from the mounting position. Meanwhile, the vertical axis indicates the magnitude of each of the first force and the second force. In FIG. 12, the change in the first force and the second force is shown when the distance between the second cassette wall 410c and the mounting position is in the range of 0 mm to 50 mm. The graph showing the change in the second force in FIG. 12 was obtained by measuring when 500 sheets of A3 size sheets P were stored in paper feed cassette 410 (the maximum paper size and the maximum number of sheets that can be stored).

[0097] In an embodiment of the present disclosure, when the paper feed cassette 410 is inserted into the paper feed device main body 401 and the rear end of the paper feed cassette 410 is pushed to a position 50 mm forward (in the pulling direction) from the installed position, the engagement portion 505 of the retraction unit 500 engages with the protrusion portion 415 of the paper feed cassette 410, and the retraction unit 500 begins to retract the paper feed cassette 410.

[0098] 10 and 11, rail portion 412 has contact surface 412a that contacts roller 405 provided on guide frame 403. Contact surface 412a includes first inclined portion 412a1, second inclined portion 412a2, and reference horizontal portion 412a3. First inclined portion 412a1 and second inclined portion 412a2 are provided in a region (first range) where contact surface 412a of rail portion 412 contacts roller 405 while sheet feed cassette 410 is being retracted by retraction unit 500 in the insertion direction.

[0099] The first inclined portion 412a1 is an inclined surface that is inclined downward in the front-rear direction toward the insertion direction of the sheet feed cassette 410.

[0100] In this embodiment, the first inclined portion 412a1 is provided so as to be inclined so as to be 3.5 mm lower than the reference height in the area between the front end and a position 10 mm away from the rear end in the rail portion 412 as shown in FIG. 11. The height of the rail portion 412 when the paper feed cassette 410 is in the mounting position, in other words, the height of the reference horizontal portion 412a3, is set as the reference height. The paper feed cassette 410 is in the mounting position when the first boss 413 is inserted into the first boss hole 406 and the second boss 414 is inserted into the second boss hole 407, respectively, the paper feed cassette 410 is aligned in the paper feed device main body 401, and the paper feed cassette 410 is in a state in which it can feed paper. The height of the front end of the rail portion 412 coincides with this reference height. In the paper feed device 400 according to the embodiment, the height difference of the first inclined portion 412a1 is set to be 3.5 mm, but is not limited to this. For example, it can be set appropriately between 1.5 mm and 4.5 mm.

[0101] The second inclined portion 412a2 is an inclined surface that inclines so as to return to the reference height between a position 10 mm away from the front end of the rail portion 412 in the rear direction and a position 22 mm away (a position 32 mm away from the front end in the rear direction) in the front-rear direction. In other words, the second inclined portion 412a2 is connected to the end of the first inclined portion 412a1 on the insertion direction side, and inclines so as to become higher toward the insertion direction.

[0102] The second inclined portion 412a2 has an inclination that compensates for the difference in height between the first inclined portion 412a1 and the reference horizontal portion 412a3 (reference height) in order to provide the first inclined portion 412a1 in the rail portion 412. However, when the lowest position of the first inclined portion 412a1 is the reference height, the second inclined portion 412a2 can be omitted.

[0103] In this manner, the contact surface 412a of the rail portion 412 includes the first inclined portion 412a1, the second inclined portion 412a2, and the reference horizontal portion 412a3. When the rollers 405 of the guide frame 403 contact the first inclined portion 412a1 of the rail portion 412, a force that draws in the sheet feed cassette 410 can be generated by the weight of the sheet feed cassette 410, as shown in FIG.

[0104] That is, when the first inclined portion 412a1 of the rail portion 412 comes into contact with the roller 405, a load (vertical direction, downward force F1) is applied from the paper feed cassette 410 at the contact position between the two, a force (front-rear direction, force F2 in the insertion direction) that pulls the paper feed cassette 410 toward the mounting position, and a force (force F3) that moves the paper feed cassette 410 in the insertion direction due to the contact of the first inclined portion 412a1 with the roller 405. At this time, force F3 corresponds to the resultant force of forces F1 and F2.

[0105] Therefore, at the position where the first inclined portion 412a1 of the rail portion 412 and the roller 405 of the guide frame 403 come into contact with each other, a force F2 that draws the sheet feed cassette 410 toward the mounting position can be generated.

[0106] Incidentally, in the sheet feeding device 400, when the sheet feeding cassette 410 is in the mounting position, the front end of the rail portion 412 coincides with the front end of the guide frame 403. Also, as described above, the first inclined portion 412a1 is provided in a range that is 10 mm from the front end of the rail portion 412 toward the rear.

[0107] Therefore, in a range where the distance between the sheet feed cassette 410 and the mounting position is 10 mm or less, the first inclined portion 412a1 comes into contact with the rollers 405 of the guide frame 403. Therefore, as shown in Fig. 9, in a range where the first force is smaller than the second force, the pulling force generated by the first inclined portion 412a1 can be utilized.

[0108] Therefore, as shown in FIG. 12, in the paper feeding device 400 of the embodiment, even when the distance between the paper feeding cassette 410 and the mounting position is within a range of 10 mm or less, it is possible to prevent the force (first force) to retract the paper feeding cassette 410 from becoming smaller than the force (second force) required to move the paper feeding cassette 410 to the mounting position.

[0109] When the sheet cassette 410 is pulled out from the sheet feeding device main body 401, the first inclined portion 412a1 of the rail portion 412 moves from bottom to top while abutting against the roller 405, generating a force that inhibits the force acting in the pulling direction. However, in the range where the distance between the mounting position and the sheet cassette 410 is 10 mm, the tensile force of the spring 502 of the retracting unit 500 is small. Therefore, when the sheet cassette 410 is pulled out from the sheet feeding device main body 401, it is possible to suppress the force acting in the pulling direction from becoming large in the range where the distance between the mounting position and the sheet cassette 410 is 10 mm or less.

[0110] In addition, it is preferable that the starting point of the second inclined portion 412a2 in the rail portion 412, i.e., the junction point between the reference horizontal portion 412a3 and the second inclined portion 412a2, and the starting point of the first inclined portion 412a1, i.e., the junction point between the second inclined portion 412a2 and the first inclined portion 412a1, are within the range where the paper feed cassette 410 abuts against the roller 405 while receiving the first force from the retraction unit 500, and are positions where they are not affected by other loads.

[0111] Moreover, the rail portion 412, whose contact surface 412a includes the first inclined portion 412a1 and the second inclined portion 412a2, is provided on the fourth cassette wall portion 410e, which is closer to the center of gravity of the sheet feed cassette 410 in the left-right direction when the sheets P are placed thereon, out of the third cassette wall portion 410d and the fourth cassette wall portion 410e extending in the front-rear direction. Moreover, the pull-in unit 500 is provided on the right guide frame 403, which is provided with the roller 405 that contacts the rail portion 412 provided on the fourth cassette wall portion 410e.

[0112] In this way, rail portion 412 including abutment surface 412a is provided on fourth cassette wall portion 410e on the side closer to the center of gravity of sheet feed cassette 410 in the left-right direction. Also, pull-in unit 500 is provided on right guide frame 403 equipped with rollers 405 that abut against rail portion 412. Therefore, when sheet feed cassette 410 is inserted into sheet feeder main body 401, sheet feed cassette 410 can be smoothly guided into sheet feeder main body 401 without getting stuck.

[0113] (Modification) Next, a configuration of a sheet feeding device 400 according to a modified example of the embodiment will be described with reference to Fig. 14. Fig. 14 is a diagram showing a schematic diagram of the height difference of rail portions 412 of a sheet feeding cassette 410 according to a modified example of the embodiment.

[0114] Compared with sheet feeding device 400 according to the embodiment, sheet feeding device 400 according to the modified embodiment differs in the shape of contact surface 412a of rail portion 412. Since the configuration of sheet feeding device 400 according to the embodiment is otherwise similar to that of sheet feeding device 400 according to the embodiment, similar members are denoted by the same reference numerals and descriptions thereof will be omitted.

[0115] That is, in the rail portion 412 according to the modified embodiment, the range in which the second inclined portion 412a2 of the contact surface 412a is formed is longer than the range in which the second inclined portion 412a2 of the contact surface 412a of the rail portion 412 according to the embodiment is formed. In addition, in the contact surface 412a of the rail portion 412 according to the embodiment, the second inclined portion 412a2 has one inclined surface that is linearly inclined, whereas in the contact surface 412a of the rail portion 412 according to the modified embodiment, the second inclined portion 412a2 has two inclined surfaces sandwiching a horizontal surface. That is, the second inclined portion 412a2 is formed in a stepped shape in which inclined surfaces and horizontal surfaces are alternately arranged.

[0116] In this way, in rail portion 412 according to the modified embodiment, second inclined portion 412a2 of abutment surface 412a is formed in a stepped shape, so that the height difference from the reference height caused by first inclined portion 412a1 can be eliminated in stages. Therefore, in rail portion 412 according to the modified embodiment, when sheet cassette 410 is pulled out from sheet feeding device main body 401, sheet cassette 410 can move more smoothly on roller 405 toward first inclined portion 412a1 when second inclined portion 412a2 abuts against roller 405. [Explanation of symbols]

[0117] 100 Image forming device 102 Image forming section 400 Paper feeder 401 Paper feeder main body 401a Bottom of paper feeder 401b Rear wall 401c Left side wall 401d Right side wall 403 Guide Frame 405 Coro 406 First boss hole 406a Uneven part 407 Second boss hole 408 Size detection switch 409 Lever 410 Paper feed cassette 410a bottom 410b First cassette wall 410c Second cassette wall 410d Third cassette wall 410e 4th cassette wall 411a 1st guide clip 411b 2nd guide clip 412 Rail section 412a Contact surface 412a1 1st slope part 412a2 2nd slope part 412a3 Reference horizontal part 412b Contact surface 413 First Boss 414 Second Boss 415 Protrusion 420 Sheet supply unit 500 Retraction Unit 501 Damper section 502 Spring 503 Case 504 Rod 505 Engagement part 505a 1st contact part 505b 2nd contact part 505c First guide shaft 505d Second guide shaft 506 Guide groove P-sheet

Claims

1. A main body portion, a paper feed cassette that is insertable into and removable from the main body in a first direction, the main body portion includes a retracting device that retracts the paper feed cassette to a mounting position, and a support member that supports the paper feed cassette; the sheet feed cassette has a rail portion extending in the first direction and abutting on the support member, A paper feeding device having a first inclined portion that is inclined so as to become higher in the direction of pulling out the paper feed cassette in the area where the rail portion abuts the support member when the force used by the retraction device to retract the paper feed cassette becomes smaller than the force required to move the paper feed cassette to the installation position.

2. 2 . The paper feeder according to claim 1 , wherein the rail portion includes a second inclined portion connected to an end of the first inclined portion on a side of an insertion direction of the paper feed cassette, the second inclined portion being inclined so as to become higher toward the insertion direction.

3. The paper feeder according to claim 2 , wherein the second inclined portion is inclined in a stepped manner.

4. The paper feeder according to claim 3 , wherein the second inclined portion includes two or more inclined surfaces and one or more horizontal surfaces connected to the two or more inclined surfaces.

5. the rail portion has a reference horizontal portion extending in the first direction so that the sheet feed cassette is at a predetermined reference height in the mounting position; 5. The paper feeder according to claim 4, wherein the height of the horizontal plane is lower than the height of the reference horizontal portion.

6. The paper feeder according to claim 1 , wherein the drawing device is provided on a guide frame that extends in the first direction and guides the paper feed cassette to the mounting position.

7. 7. The paper feed device according to claim 6, wherein the support member is a rotating body that rotates so that the paper feed cassette is relatively movable in the first direction with respect to the guide frame.

8. the support member is provided at an end of the guide frame in a direction in which the sheet feed cassette is pulled out, or at a position adjacent to the end of the guide frame in the direction in which the sheet feed cassette is pulled out, 8. The paper feed device according to claim 6, wherein the first inclined portion is provided at an end of the rail portion on a side in a direction in which the paper feed cassette is pulled out.

9. The paper feed cassette has a bottom surface on which paper is placed and a plurality of side walls connected to an edge of the bottom surface and extending upright from the bottom surface; When a direction perpendicular to the first direction on the bottom surface is defined as a second direction, The plurality of side wall portions include a first side wall portion disposed at an end portion on one side of the bottom surface in the second direction and extending in the first direction, and a second side wall portion disposed at an end portion on the other side in the second direction and extending in the first direction, the first side wall portion is disposed at a position closer to a center of gravity of the paper feed cassette than the second side wall portion is disposed in the second direction; The paper feeder according to claim 1 , wherein the rail portion is provided on the first side wall portion.

10. the sheet feed cassette includes a protruding portion that is a rod member protruding in an insertion direction of the sheet feed cassette, The main body portion includes a hole through which the protrusion is inserted, The paper feeder according to claim 1 , wherein at least a part of an inner periphery of the hole has an uneven shape.

11. A paper feeder according to any one of claims 1 to 10, an image forming unit that forms an image on the paper fed from the paper feeder.

Images