JP2016069121A - Paper feeder and image formation device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeder which inhibits a sheet from remaining in a device body when a paper cassette is drawn, and to provide an image formation device including the paper feeder.SOLUTION: A paper feeding part includes: a body housing; a paper cassette; a pickup roller 112; a holder 20J; and a linkage part 50. The holder 20J is swingably supported by the body housing and rotatably supports the pickup roller 112. The holder 20J changes a position of the pickup roller 112 between a paper feeding position where the pickup roller 112 contacts with a sheet S and a lower end position where the pickup roller 112 is located below the paper feeding position. The linkage part 50 is disposed in the body housing 10 and moves the pickup roller 112 from the lower end position to the paper feeding position side in conjunction with drawing operation of the paper cassette 110.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a sheet feeding device that feeds a sheet and an image forming apparatus including the sheet feeding device.

  2. Description of the Related Art Conventionally, an apparatus mounted on an image forming apparatus is known as a sheet feeding apparatus that feeds sheets. The sheet feeding device includes a sheet feeding cassette that is detachable from the apparatus main body of the image forming apparatus, and a pickup roller, a sheet feeding roller, and a retard roller that are disposed in the apparatus main body. A sheet is accommodated in the paper feed cassette. Then, the sheet is fed in the sheet conveyance direction by rotating the pickup roller.

  The sheet fed by the pickup roller is carried into a sheet feeding nip formed by the sheet feeding roller and the retard roller. The sheet is further conveyed downstream in the sheet conveying direction by the rotation of the sheet feeding roller.

  Japanese Patent Application Laid-Open No. 2004-133830 discloses a paper feeding device having a return mechanism that returns a sheet to the paper feeding cassette side in order to prevent the sheet from remaining in the device main body when the paper feeding cassette is pulled out from the device main body. It is disclosed. The return mechanism projects in the sheet conveyance path in conjunction with the drawer operation of the paper feed cassette, and pushes the sheet back toward the paper feed cassette.

JP 2011-68476 A

  In the technique described in Patent Document 1, the return mechanism is composed of a plurality of members, and is divided into an apparatus main body and a paper feed cassette. For this reason, there is a problem in that the protrusion of the return mechanism is delayed due to variations in the shape of the parts and the timing at which the paper cassette is pulled out, and the sheet does not return to the paper cassette.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet feeding device that suppresses sheets from remaining in the apparatus main body when the sheet feeding cassette is pulled out, and an image forming apparatus including the sheet feeding device. Objective.

  A sheet feeding device according to an aspect of the present invention includes an apparatus main body, a sheet feeding cassette that is mounted toward the apparatus main body in a predetermined mounting direction and that stores a sheet, and the apparatus. In the main body, the sheet accommodated in the sheet accommodating portion is conveyed in the sheet conveying direction along the mounting direction, and in the apparatus main body, the sheet accommodated in the sheet accommodating portion in the sheet accommodating path. A pickup roller disposed opposite to the leading end side in the mounting direction, rotationally driven, and sending out the sheet in the sheet conveying direction, and a shaft portion, arranged downstream of the pickup roller in the sheet conveying direction, A sheet feed roller that is driven to rotate around a shaft portion and conveys the sheet in the sheet conveyance direction, and is disposed to face the sheet feed roller. A retard roller that forms a nip portion through which the sheet passes between the roller and one end of the roller is supported by the apparatus main body so as to be rotatable around the shaft portion. The other end of the pickup roller can be changed between a sheet feeding position where the sheet can be fed in contact with the sheet accommodated in the sheet accommodating portion and a lower end position below the sheet feeding position. A holder that rotatably supports the pickup roller in the section, and a sheet storage section that is disposed so as to be able to move up and down. The sheet is stacked on the upper surface, and the pickup roller that is disposed at the lower end position is pushed up with the upward movement. While swinging the holder, the pickup roller is disposed at the paper feeding position, and the holder is moved to the shaft portion as it moves downward. And the pickup roller is allowed to be disposed again at the lower end position, and the lift plate for separating the sheet from the pickup roller, and the apparatus main body, the apparatus of the sheet cassette And a moving mechanism for moving the pickup roller from the lower end position to the paper feeding position side in conjunction with a pulling operation from the main body.

  According to this configuration, after the sheet stored in the sheet storage portion of the paper feed cassette is fed out by the pickup roller, the sheet passes through the nip portion between the paper feed roller and the retard roller, and further in the sheet transport direction. Be transported. When the sheet feeding cassette is pulled out from the apparatus main body with the leading end of the sheet positioned in the vicinity of the nip portion, a load is applied to the sheet due to friction between the sheet and the pickup roller, and the sheet tends to remain in the apparatus main body. According to the above configuration, the moving mechanism moves the pickup roller from the lower end position to the sheet feeding position side in conjunction with the operation of pulling out the sheet feeding cassette from the apparatus main body. This prevents the pickup roller from restricting the movement of the sheet when the paper feeding cassette is pulled out. As a result, the sheet is pulled out from the apparatus main body together with the sheet feeding cassette, and the remaining of the sheet in the apparatus main body is suppressed. Further, since the moving mechanism is arranged on the apparatus main body side, the positional accuracy of the moving mechanism is maintained, and the position change of the pickup roller is stably realized.

  In the above configuration, the moving mechanism is rotatably supported by the apparatus main body, and when the paper feeding cassette starts to be pulled out from the apparatus main body, the moving mechanism is rotated by the paper feeding cassette, It is desirable that the pickup roller moves from the lower end position to the paper feed position side by the movement mechanism swinging the holder.

  According to this configuration, the swinging of the holder and the movement of the pickup roller are quickly realized by the pulling-out operation of the paper feed cassette.

  In the above configuration, the paper feed cassette includes a side wall including an upper surface portion and extending in the mounting direction, and the side wall of the upper surface portion partially protrudes upward in the mounting direction, along the mounting direction. The holder has a protrusion, and the moving mechanism extends in the sheet width direction intersecting the mounting direction and is rotatably supported by the apparatus main body. A shaft, a protruding piece extending in a radial direction from one end side of the shaft, a contact piece capable of contacting the protruding wall, and a protruding piece extending in a radial direction from the other end side of the shaft; A push-up portion engageable with the protrusion of the holder, and in the mounted state of the paper feed cassette with respect to the apparatus main body, the contact piece is closer to the rear end side in the mounting direction than the protruding wall. The upper surface portion of the side wall When the sheet feeding cassette is arranged at the upper standby position and starts to be pulled out from the apparatus main body, the protruding wall interferes with the abutting piece and presses the abutting piece, so that the moving mechanism rotates around the shaft. It is desirable that the push-up portion abuts against the protrusion while being rotated, pushes the holder upward, and the pickup roller moves from the lower end position to the paper feed position side.

  According to this configuration, the rotation of the moving mechanism is realized using the side wall of the paper feed cassette. For this reason, the swinging of the holder and the movement of the pickup roller are quickly realized.

  In the above configuration, when the protruding wall passes through the contact piece in the pulling-out operation of the paper feed cassette, the moving mechanism is rotated around the shaft by the weight of the holder, and the contact piece is again moved to the contact piece. It is desirable to arrange at the standby position.

  According to this configuration, when the paper cassette is pulled out, the contact piece can quickly return to the standby position by the weight of the holder.

  In the above configuration, the sheet feeding cassette includes a front wall that stands up along the sheet width direction on the leading end side in the mounting direction and defines a leading end position of the sheet, and the apparatus main body of the sheet feeding cassette In the mounted state, the length of the protruding wall in the mounting direction is preferably longer than the distance in the mounting direction between the tip wall and the axis of the pickup roller.

  According to this configuration, since the length of the protruding wall is set to be larger than the distance between the front wall and the axis of the pickup roller, the pickup roller is moved until the front wall passes under the pickup roller. It can be reliably arranged on the paper feed position side. Therefore, the sheet is pulled out from the apparatus main body together with the sheet feeding cassette, and the remaining of the sheet in the apparatus main body is stably suppressed.

  In the above-described configuration, the sheet feeding cassette is provided upright along the sheet width direction on the leading end side in the mounting direction, and includes a front wall that defines the leading end position of the sheet. Preferably, the front wall of the protruding wall reaches the rear end side in the mounting direction with respect to the axis of the pickup roller before the front end in the mounting direction of the protruding wall passes through the contact piece.

  According to this configuration, the pickup roller can be reliably arranged on the paper feed position side until the front wall passes below the pickup roller. Therefore, the sheet is pulled out from the apparatus main body together with the sheet feeding cassette, and the remaining of the sheet in the apparatus main body is stably suppressed.

  An image forming apparatus according to another aspect of the present invention includes any one of the sheet feeding devices described above and an image forming unit that forms an image on a sheet conveyed by the sheet feeding roller.

  According to this configuration, the sheet is pulled out from the apparatus main body together with the sheet feeding cassette, and the remaining of the sheet in the apparatus main body is suppressed. Further, since the moving mechanism is arranged on the apparatus main body side, the positional accuracy of the moving mechanism is maintained, and the position change of the pickup roller is stably realized. As a result, it is possible to stably form an image on a sheet while suppressing sheet jamming in the apparatus main body.

  According to the present invention, there are provided a sheet feeding device that suppresses a sheet from remaining in the apparatus main body when the sheet feeding cassette is pulled out, and an image forming apparatus including the sheet feeding device.

1 is a cross-sectional view schematically showing an internal structure of an image forming apparatus including a paper feeding device according to an embodiment of the present invention. It is a perspective view of a paper feed cassette and a paper feed unit according to an embodiment of the present invention. It is a perspective view of a paper feed unit of a paper feed device according to an embodiment of the present invention. FIG. 4 is a perspective view (A) of a moving mechanism of a paper feeding device according to an embodiment of the present invention, and an enlarged perspective view (B) of a part of an apparatus main body that supports the moving mechanism. In the sheet feeder according to the embodiment of the present invention, (A) a side view of the sheet feed unit and the sheet feed cassette in a state where the sheet feed cassette is mounted on the apparatus body, and (B) a view of the sheet feed unit and the sheet feed cassette. It is sectional drawing and (C) Sectional drawing of a paper feeding unit. In the sheet feeder according to the embodiment of the present invention, (A) a side view of the sheet feed unit and the sheet feed cassette when the sheet feed cassette is pulled out from the apparatus main body, and (B) a cross section of the sheet feed unit and the sheet feed cassette. FIG. 3C is a cross-sectional view of the paper feeding unit. In the sheet feeding device according to the embodiment of the present invention, (A) a side view of the sheet feeding unit and the sheet feeding cassette in a state where the sheet feeding cassette is further pulled out from the apparatus main body, and (B) the sheet feeding unit and the sheet feeding cassette. FIG. 4A is a side view of a paper feeding unit and a paper feeding cassette when the paper feeding cassette is mounted on the apparatus main body, and FIG. 5B is a cross-sectional view of the paper feeding unit. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side sectional view showing an internal structure of an image forming apparatus 1 according to an embodiment of the present invention. Here, a monochrome printer is illustrated as the image forming apparatus 1, but the image forming apparatus may be a copying machine, a facsimile machine, or a multifunction machine having these functions, and an image forming apparatus that forms a color image. It may be.

  The image forming apparatus 1 includes a main body housing 10 (apparatus main body) having a substantially rectangular parallelepiped housing structure, a paper feeding unit 20 (paper feeding device) accommodated in the main body housing 10, and an image forming unit 30. A fixing unit 40 and a toner container 36.

  A front cover 11 is provided on the front side of the main body housing 10, and a rear cover 12 is provided on the rear side. Further, on the upper surface of the main body housing 10, a paper discharge unit 13 for discharging the sheet after image formation is provided. Various devices for executing image formation are housed in an internal space 10 </ b> S defined by the front cover 11, the rear cover 12, and the paper discharge unit 13.

  The image forming unit 30 performs an image forming process for forming a toner image on a sheet S fed from the paper feeding unit 20 (a paper feeding roller 113 described later). The image forming unit 30 includes a photosensitive drum 31, and a charging device 32, an exposure device (not shown in FIG. 2), a developing device 33, a transfer roller 34, and a cleaning device disposed around the photosensitive drum 31. 35.

  An electrostatic latent image is formed on the photosensitive drum 31 and a toner image corresponding to the electrostatic latent image is carried on the cylindrical surface. The charging device 32 uniformly charges the surface of the photosensitive drum 31. The cleaning device 35 cleans the toner adhering to the peripheral surface of the photosensitive drum 31 after the toner image is transferred, and conveys the toner to a collecting device (not shown).

  The exposure apparatus has a laser light source and optical equipment such as a mirror and a lens, and irradiates the peripheral surface of the photosensitive drum 31 with light modulated based on image data given from an external device such as a personal computer. An electrostatic latent image is formed. The developing device 33 supplies toner to the peripheral surface of the photosensitive drum 31 in order to develop the electrostatic latent image on the photosensitive drum 31 to form a toner image. The transfer roller 34 transfers the toner image formed on the peripheral surface of the photosensitive drum 31 onto the sheet.

  The fixing unit 40 performs a fixing process for fixing the transferred toner image on the sheet. The fixing unit 40 includes a fixing roller 41 having a heating source therein, and a pressure roller 42 that is pressed against the fixing roller 41 and forms a fixing nip portion with the fixing roller 41. When the sheet on which the toner image has been transferred is passed through the fixing nip portion, the toner image is fixed on the sheet S by heating by the fixing roller 41 and pressing by the pressure roller 42. The toner container 36 stores supply toner to be supplied to the developing device 33.

  The paper feeding unit 20 includes a paper feeding cassette 110 that stores sheets S on which image forming processing is performed. The sheet S is carried into the main conveyance path 22 </ b> F extending from the sheet feeding cassette 110 to the inside of the main body housing 10.

  In the main body housing 10, a main conveyance path 22 </ b> F (sheet conveyance path) and a reverse conveyance path 22 </ b> B are provided to convey the sheet S. The main conveyance path 22 </ b> F passes through the sheet storage unit 110 </ b> S of the paper supply unit 20 via the image forming unit 30 and the fixing unit 40, and the paper discharge port 14 provided to face the paper discharge unit 13 on the upper surface of the main body housing 10. It extends to.

  In addition, a registration roller pair 23 is disposed on the upstream side of the transfer nip portion of the main conveyance path 22F. The sheet S is temporarily stopped by the registration roller pair 23, and after skew correction is performed, the sheet S is sent to the transfer nip portion at a predetermined timing for image transfer. A plurality of transport rollers for transporting the sheet S are disposed at appropriate positions on the main transport path 22F and the reverse transport path 22B. For example, a pair of paper discharge rollers 24 is disposed in the vicinity of the paper discharge port 14.

  The reverse conveyance path 22B is a conveyance path for returning the single-side printed sheet S to the upstream side of the image forming unit 30 in the main conveyance path 22F when performing duplex printing on the sheet S. The reverse conveyance path 22 </ b> B is formed between the outer side surface of the reverse unit 25 and the inner surface of the rear cover 12 of the main body housing 10. The rear cover 12 and the reversing unit 25 can be rotated about the axis of the cover fulcrum portion 12S provided at the lower end thereof.

<About the paper feed unit>
Next, with reference to FIG. 2 and FIG. 3 in addition to FIG. 1, the paper feeding unit 20 (paper feeding device) according to the present embodiment will be described in detail. FIG. 2 is a perspective view of the paper feed cassette 110 and the paper feed unit 20A according to the present embodiment. FIG. 3 is a perspective view of the paper feeding unit 20A.

  The sheet feeding unit 20 conveys the sheet S from the sheet feeding cassette 110 to the image forming unit 30. In addition to the paper feed cassette 110 described above, the paper feed unit 20 includes a paper feed unit 20A (FIG. 3) and a retard roller 117 (FIG. 1).

  The paper feed cassette 110 is detachable from the main body housing 10 (apparatus main body). In the present embodiment, the paper feed cassette 110 is mounted on the main body housing 10 in the direction of arrow DC (a predetermined mounting direction) in FIG. The paper feed cassette 110 includes a cassette bottom wall 110A and a sheet storage portion 110S. The sheet S is accommodated in the sheet accommodating portion 110S. Further, the sheet S stored in the sheet storage unit 110S is transported through the main transport path 22F (sheet transport path) described above. The sheet S is transported along the entrance side of the main transport path 22F in the sheet transport direction along the mounting direction of the paper feed cassette 110. The paper feed cassette 110 has a box shape in which the side walls are erected upward from the front, rear, left and right of the cassette bottom wall 110A. In other words, the paper feed cassette 110 further includes a cassette front wall 110B, a cassette front wall 110C (front wall), a cassette left wall 110D, and a cassette right wall 110E (side wall).

  The cassette front wall 110 </ b> B defines the front side of the sheet storage portion 110 </ b> S of the paper feed cassette 110 and is disposed flush with the front cover 11 of the main body housing 10. The cassette front wall 110 </ b> C defines the sheet storage portion 110 </ b> S on the rear side of the sheet feeding cassette 110 and defines the leading end position of the sheet S. In other words, the cassette front wall 110 </ b> C is a wall portion erected along the sheet width direction intersecting the mounting direction on the leading end side in the mounting direction in which the paper feed cassette 110 is mounted on the main body housing 10. The cassette right wall 110E is a side wall that is arranged on the right side of the sheet feeding cassette 110 so as to intersect the cassette front wall 110C and extend in the mounting direction. The cassette left wall 110D is a side wall disposed in parallel to the cassette right wall 110E on the left side of the paper feed cassette 110. The cassette left wall 110D and the cassette right wall 110E have a predetermined width and have upper surfaces extending in the front-rear direction.

  The paper feed cassette 110 further includes a lift plate 111. The lift plate 111 is arranged to be movable up and down in the sheet storage portion 110 </ b> S of the paper feed cassette 110. The sheet S is placed on the upper surface of the lift plate 111. The lift plate 111 moves the end on the downstream side in the sheet conveyance direction of the sheet S stored in the sheet storage unit 110 </ b> S toward the pickup roller 112 by moving the rear end side upward. More specifically, the lift plate 111 includes a first position along the cassette bottom wall 110A of the sheet feeding cassette 110, and a sheet bundle stored in the sheet storage portion 110S that is above the first position. Among these, the position change is possible between the uppermost sheet S and the second position where the downstream end of the sheet S in the sheet conveying direction comes into contact with the pickup roller 112. The lift plate 111 is moved upward from the first position by an elevator (not shown) after the paper feed cassette 110 is mounted on the main body housing 10. In another embodiment, the entire lift plate 111 may be moved in the vertical direction.

  The sheet feeding unit 20 </ b> A is a unit that is mounted inside the main body housing 10. As shown in FIG. 3, the paper feed unit 20A is arranged to extend in the front-rear direction. The sheet feeding unit 20A includes a housing 20H, a pickup roller 112, a sheet feeding roller 113, a holder 20J, and an interlocking unit 50 (movement mechanism). The housing 20 </ b> H constitutes a part of the main body housing 10. The housing 20H is a housing that supports each member of the paper feeding unit 20A and is made of a resin material. A concave portion for mounting the holder 20J is formed in the central portion in the left-right direction of the housing 20H.

  The pickup roller 112 (FIG. 1) is disposed to face the sheet storage portion 110S. The pickup roller 112 is disposed above the leading end side in the mounting direction of the sheet S accommodated in the sheet accommodating portion 110S. The pickup roller 112 is disposed at the center of the sheet width direction (left-right direction) that intersects the mounting direction of the sheet feeding cassette 110. The pickup roller 112 includes a pickup roller shaft 112A (FIGS. 5C and 6C). The pickup roller 112 is supported by the holder 20J so as to be rotatable around the pickup roller shaft 112A. When the pickup roller 112 is rotationally driven via the paper feed roller 113 by a drive mechanism (not shown), the pickup roller 112 conveys (sends out) the sheet S toward the downstream side in the sheet conveyance direction.

  The paper feed roller 113 is disposed on the inlet side of the main conveyance path 22F and on the downstream side of the pickup roller 112 in the sheet conveyance direction. Similarly to the pickup roller 112, the paper feed roller 113 is also arranged at the center in the sheet width direction in the main body housing 10. The paper feed roller 113 includes a paper feed roller shaft 113A (shaft portion) (FIG. 3). The sheet feeding roller 113 is driven to rotate around the sheet feeding roller shaft 113A by a drive mechanism (not shown), thereby further conveying the sheet S sent out by the pickup roller 112 toward the downstream side in the sheet conveying direction.

  With reference to FIG. 3, the holder 20 </ b> J is disposed at the center in the left-right direction of the housing 20 </ b> H. The holder 20J is supported by the housing 20H on the rear end side so as to be rotatable around the paper feed roller shaft 113A. The holder 20J has a substantially U-shape with an open bottom surface. Further, the holder 20J supports the pickup roller 112 rotatably on the front end side. The holder 20J moves (changes the position of) the pickup roller 112 between the paper feed position and the lower end position as the holder 20J swings around the paper feed roller shaft 113A. At the sheet feeding position, the pickup roller 112 can abut on the sheet S stored in the sheet storage unit 110S (FIGS. 1 and 2) and send out the sheet S. The lower end position is a position where the pickup roller 112 has moved below the paper feed position. The movement of the pickup roller 112 due to the swinging of the holder 20J will be described in detail later. The holder 20J includes a protrusion 20K. The protrusion 20K is a protrusion protruding rightward from the right side surface of the holder 20J. The protrusion 20K is disposed in front of the paper feed roller shaft 113A and on the right side of the pickup roller 112 so as to face the interlocking unit 50. A push-up portion 503, which will be described later, can be engaged with the protrusion 20K.

  The interlocking unit 50 is disposed in the housing 20H. Specifically, the interlocking portion 50 is rotatably supported by the housing 20H on the right side of the holder 20J. The interlocking unit 50 has a function of moving the pickup roller 112 from the lower end position to the sheet feeding position side in conjunction with the operation of pulling out the sheet feeding cassette 110 from the main body housing 10. FIG. 4A is a perspective view of the interlocking unit 50 of the paper feeding unit 20 according to the present embodiment. The interlocking portion 50 includes a shaft 501, a contact piece 502, a push-up portion 503, a supported portion 504, a restricting portion 505, and a ring portion 506.

  The shaft 501 extends in the sheet width direction (left-right direction) intersecting the sheet conveyance direction, and is rotatably supported by the housing 20H. The abutting piece 502 is a protruding piece that protrudes from the right end (one end side) of the shaft 501 to extend downward (in the radial direction) and faces in the left-right direction. The contact piece 502 can be brought into contact with a protrusion 110E5 described later. The push-up portion 503 is a protruding piece that protrudes from the left end portion (the other end side) of the shaft 501 downward (radial direction) and faces in the front-rear direction. The tip of the push-up portion 503 is curved toward the front. The push-up portion 503 can be engaged with the protrusion 20K of the holder 20J. The supported portions 504 are portions (cut surfaces) in which the peripheral surface of the shaft 501 is partially cut, and are arranged in pairs as shown in FIG. The restricting portion 505 is a protrusion protruding from the peripheral surface of the shaft 501 between the pair of supported portions 504. The restricting portion 505 restricts the position in the sheet width direction (left-right direction) of the interlocking portion 50 attached to the housing 20H. The ring portion 506 is formed by setting the outer diameter of the shaft 501 wide between the contact piece 502 and the right supported portion 504.

  FIG. 4B is an enlarged perspective view of the right end side of the housing 20H to which the interlocking unit 50 is mounted. Referring to FIG. 4B, the housing 20H includes a right wall portion 20H1, a first rib 20H2, a second rib 20H3, a third rib 20H4, a fourth rib 20H5, and a fifth rib 20H6. Is provided. The right wall portion 20H1 is a wall portion arranged at the right end portion of the housing 20H. The first rib 20H2 to the fifth rib 20H6 are ribs extending in the front-rear direction with a space in the left-right direction on the left side of the right wall portion 20H1, that is, inside the housing 20H. The rigidity of the housing 20H is kept high by these ribs.

  Further, as shown in FIG. 4B, the housing 20H includes a first support hole 20G1, a first notch 20G2, a second notch 20G3, a third notch 20G4, and a fourth notch. A notch 20G5 and a second support hole 20G6 are provided. All of these are formed by partially notching the lower end portion of the fifth rib 20H6 from the right wall portion 20H1. Further, the first support hole 20G1 to the second support hole 20G6 are arranged so as to be adjacent along the left-right direction. The first support hole 20G1 and the second support hole 20G6 are support parts that support the shaft 501 of the interlocking part 50. Both the first support hole 20G1 and the second support hole 20G6 have a keyhole shape including an insertion hole and a circular hole. The first cutout portion 20G2, the third cutout portion 20G4, and the fourth cutout portion 20G5 are opened in a substantially V shape. On the other hand, the 2nd notch part 20G3 is opened by the substantially U shape, and the opening width of the 2nd notch part 20G3 is the 1st notch part 20G2, the 3rd notch part 20G4, and the 4th notch part. It is set narrower than the opening width of 20G5.

  Next, with reference to FIG. 4 (A) and FIG. 4 (B), the procedure in which the interlocking | linkage part 50 is mounted | worn with the housing 20H is demonstrated. The operator aligns the supported portion 504 with the first support hole 20G1 and the first support hole 20G1 while matching the cut surfaces of the pair of supported portions 504 of the interlocking portion 50 with the insertion holes at the entrances of the first support hole 20G1 and the second support hole 20G6. 2 Insert into the support hole 20G6 (arrows D41 and D42 in FIG. 4B). At this time, the central portion of the shaft 501 enters the first notch 20G2, the second notch 20G3, the third notch 20G4, and the fourth notch 20G5. Note that the restricting portion 505 protruding from the shaft 501 is disposed between the first rib 20H2 and the second rib 20H3. Next, the operator rotates the shaft 501 around the axis so that the restricting portion 505 faces the lower side, that is, the opening side of the second notch portion 20G3. Thereafter, the operator slides the interlocking unit 50 leftward (arrows D43 and D44 in FIG. 4B). Then, the sliding movement of the interlocking portion 50 is stopped by the ring portion 506 coming into contact with the right side surface of the right wall portion 20H1. At this time, the restricting portion 505 is disposed on the left side of the second rib 20H3. Further, the operator rotates the shaft 501 backward about the axis. As a result, the restricting portion 505 is disposed close to the left side surface of the second rib 20H3.

  As described above, when the interlocking portion 50 is mounted on the housing 20H, the restriction portion 505 contacts the left side surface of the second rib 20H3, thereby restricting movement of the interlocking portion 50 to the right side. On the other hand, when the ring part 506 contacts the right side surface of the right wall part 20H1, the movement of the interlocking part 50 to the left side is restricted. As a result, the interlocking unit 50 is disposed within a predetermined range in the left-right direction. Furthermore, with the reverse rotation of the shaft 501, the cut surfaces of the pair of supported portions 504 are disposed at positions shifted in the circumferential direction from the insertion holes of the first support hole 20G1 and the second support hole 20G6. For this reason, the interlocking part 50 is prevented from being detached downward from the housing 20H.

  The retard roller 117 is disposed below the paper feed roller 113 so as to face the paper feed roller 113. The retard roller 117 is rotatably supported by a frame (not shown) of the main body housing 10. The retard roller 117 forms a paper feed nip portion (nip portion) through which the sheet S enters and passes with the paper feed roller 113. The main transport path 22F is extended from the sheet storage portion 110S of the paper feed cassette 110 so as to pass through the paper feed nip portion. The retard roller 117 is rotatable following the paper feed roller 113. When a plurality of sheets S enter the sheet feeding nip portion, only the uppermost sheet S is conveyed downstream in the sheet conveying direction by the sheet feeding roller 113. The other sheets S are rolled by contacting the peripheral surface of the retard roller 117 and stopped at the paper feed nip portion.

  5A is a side view of the paper feeding unit 20A and the paper feeding cassette 110 in a state where the paper feeding cassette 110 is mounted on the main body housing 10 in the paper feeding unit 20 according to the present embodiment, and FIG. FIG. 6 is a cross-sectional view of the unit 20A and the paper feed cassette 110 and (C) a cross-sectional view of the paper feed unit 20A. 6A is a side view of the paper feeding unit 20A and the paper feeding cassette 110 when the paper feeding cassette 110 is pulled out from the paper feeding cassette 110. FIG. 6B is a sectional view of the paper feeding unit 20A and the paper feeding cassette 110. (C) It is sectional drawing of 20 A of paper feed units. 7A is a side view of the paper feeding unit 20A and the paper feeding cassette 110 in a state in which the paper feeding cassette 110 is further pulled out from the main body housing 10 than in the state of FIG. 6, and FIG. 2 is a cross-sectional view of the paper feed cassette 110. FIG.

  With reference to FIG. 2 and FIG. 5A, the cassette right wall 110E of the paper feed cassette 110 is provided with a top end surface portion 110E1. The top end portion 110E1 is a tip end portion in the mounting direction of the sheet feeding cassette 110 in the top portion of the cassette right wall 110E. The top end surface portion 110E1 includes a first inclined portion 110E2, a horizontal portion 110E3, and a second inclined portion 110E4. The first inclined portion 110E2 is an inclined portion formed at the tip of the cassette right wall 110E. The first inclined portion 110 </ b> E <b> 2 is formed so as to descend downward along the mounting direction of the paper feed cassette 110. The horizontal portion 110E3 is connected to the front side of the first inclined portion 110E2 and extends substantially horizontally. The second inclined part 110E4 is an inclined part connected to the front side of the horizontal part 110E3. The second inclined portion 110 </ b> E <b> 4 is formed so as to rise forward along the mounting direction of the paper feed cassette 110.

  Referring to FIG. 5A, the cassette right wall 110E further includes a protruding portion 110E5 (a protruding wall). The protruding portion 110E5 is a portion of the horizontal portion 110E3 that has a predetermined length along the mounting direction, with the leading end side in the mounting direction of the paper feed cassette 110 partially protruding upward.

  With reference to FIGS. 5A, 5 </ b> B, and 5 </ b> C, a state in which the pickup roller 112 is disposed at the paper feed position will be described. When the paper feed cassette 110 is inserted into the main body housing 10, the holder 20J is disposed below the paper feed roller shaft 113A below the paper feed position shown in FIGS. 5A and 5B due to its own weight. Has been. This position is defined as the lower end position of the pickup roller 112. At this time, the first hook piece 20F1 projecting downward from the top plate of the housing 20H engages with the second hook piece 20F2 projecting upward from the holder 20J, so that the holder 20J further moves from the lower end position. It is prevented from rotating downward (see FIG. 8B). When the leading end side of the lift plate 111 (FIG. 1) is moved upward (upward movement) by an unillustrated lifting / lowering unit (upward movement), the uppermost sheet S of the sheet bundle on the lift plate 111 is eventually positioned at the lower end position. It abuts on the pick-up roller 112 arranged at the top and pushes it up. Further, when the lift plate 111 is moved upward, the holder 20J is swung, and a light shielding piece (not shown) provided in the holder 20J is detected by a PI (photo interrupter) sensor (not shown) provided in the housing 20H. Is done. As a result, the upward movement of the lift plate 111 is stopped, and the pickup roller 112 is disposed at the paper feed position shown in FIGS. 5 (A), (B), and (C). The housing 20H is provided with a stopper (not shown). The stopper restricts the swinging of the holder 20J so that the pickup roller 112 does not move above the paper feed position.

  In a state where the paper feed cassette 110 is mounted on the main body housing 10 and the pickup roller 112 is disposed at the paper feed position, as shown in FIG. 5A, the contact piece 502 is behind the protrusion 110E5 in the mounting direction. On the end side (front side), it is disposed at a standby position above the horizontal portion 110E3. At this time, the contact piece 502 is arranged so as to extend downward due to the rotational moment caused by the contact piece 502 and the push-up portion 503 of the interlocking portion 50, and a predetermined amount is provided between the contact piece 502 and the horizontal portion 110E3. The gap is formed. Further, inside the housing 20H, as shown in FIG. 5C, the push-up portion 503 is also arranged so as to extend downward. A protrusion 20K of the holder 20J is disposed in front of the push-up portion 503 with a predetermined gap. Further, the lower end portion of the push-up portion 503 is disposed slightly above the lower end portion of the peripheral surface of the pickup roller 112. For this reason, when the sheet S is sent out by the pickup roller 112, the push-up portion 503 does not hinder the movement of the sheet S.

  When the pickup roller 112 is rotated in the state shown in FIG. 5B, the sheet S on the lift plate 111 moves toward the sheet feeding nip portion between the sheet feeding roller 113 and the retard roller 117 (FIG. 1). It is sent out. At this time, a plurality of sheets S may jump out immediately before the sheet feeding nip portion, but the sheet feeding roller 113 conveys the sheets S one by one downstream in the sheet conveying direction while the sheets S are being rolled by the retard roller 117. .

  In the image forming apparatus 1 (sheet feeding unit 20), when the sheet S feeding operation is completed, the lift plate 111 is lowered (downward movement) by the elevating unit. At this time, the pickup roller 112 that is in contact with the sheet S on the lift plate 111 also descends following the lift plate 111 due to the swing of the holder 20J about the sheet feeding roller shaft 113A. By reaching the aforementioned lower end position, the pickup roller 112 descends, that is, the swing of the holder 20J stops. Thereafter, the lift plate 111 moves down to the first position along the cassette bottom wall 110 </ b> A of the paper feed cassette 110. As a result, the sheet S on the lift plate 111 and the pickup roller 112 are separated from each other. Thus, the downward movement of the lift plate 111 allows the pickup roller 112 to be placed again at the lower end position. In this state, when the sheet cassette 110 is pulled forward by the user, among the sheet bundles stacked on the lift plate 111, the sheet S whose leading end is located around the sheet feeding nip portion is disposed at the lower end position. Contact with the peripheral surface of the pickup roller 112. For this reason, the pickup roller 112 prevents the movement of the sheet S, and the sheet S tends to remain in the main body housing 10. Next, when the sheet feeding cassette 110 is inserted, the remaining sheet S causes a sheet jam in the main body housing 10. In the present embodiment, the interlocking portion 50 provided in the housing 20H solves such a problem.

  That is, when the paper feeding cassette 110 starts to be pulled out from the main body housing 10, the interlocking unit 50 is rotated by the paper feeding cassette 110, and the interlocking unit 50 pushes up and swings the holder 20J, so that the pickup roller 112 is moved. Move from the lower end position to the paper feed position.

  Specifically, when the paper feeding cassette 110 starts to be pulled out with the pickup roller 112 disposed at the lower end position (arrow D61 in FIG. 6A), the protruding portion 110E5 interferes with the contact piece 502, and the contact is made. By pressing the piece 502, the contact piece 502 rotates in the direction of arrow D62 in FIG. At this time, while the interlocking portion 50 is rotated around the shaft 501, the push-up portion 503 contacts the protrusion 20K and pushes up the holder 20J (arrow D63 in FIG. 6C). As a result, the pickup roller 112 moves from the lower end position to the paper feeding position. While the projecting portion 110E5 passes below the contact piece 502, the rotating state of the interlocking portion 50 and the state where the pickup roller 112 is disposed at the paper feed position are maintained. Note that the movement destination of the pickup roller 112 when the push-up portion 503 pushes the protrusion 20K upward may be the paper feed position, or may be a position slightly below the paper feed position. In any case, it is only necessary that the pickup roller 112 is moved upward from the lower end position and strong contact between the sheet S and the pickup roller 112 is suppressed when the sheet feeding cassette 110 is pulled out. On the other hand, when the pickup roller 112 attempts to move further upward than the paper feed position, the stopper (not shown) restricts the swing of the holder 20J as described above. For this reason, in order to prevent damage to the holder 20J and the like, it is desirable that the uppermost position of the movement destination of the pickup roller 112 is the paper feed position.

  When the sheet cassette 110 is continuously pulled out and the protrusion 110E5 reaches the rear end side (front side) in the mounting direction with respect to the contact piece 502 (FIG. 7A), the contact piece 502 formed by the protrusion 110E5. The pressure on is released. As a result, the interlocking portion 50 is rotated around the shaft 501 by the weight of the holder 20J, and the contact piece 502 is disposed at the standby position so as to extend downward again. The holder 20J moves to a position below the paper feed position, and the first hook piece 20F1 and the second hook piece 20F2 engage with each other, whereby the pickup roller 112 stops at the lower end position. As described above, when the paper cassette 110 is completely pulled out, the interlocking unit 50 is rotated by the weight of the holder 20J, and the contact piece 502 can be quickly returned to the standby position.

  Thus, in the present embodiment, the swinging of the holder 20J and the movement of the pickup roller 112 are quickly realized by the pulling-out operation of the paper feed cassette 110. In particular, when the paper feeding cassette 110 is pulled out, the pickup roller 112 moves toward the paper feeding position, so that strong rubbing between the sheet S and the pickup roller 112 whose leading edge has reached the vicinity of the paper feeding nip portion is suppressed. . Therefore, the pickup roller 112 is prevented from restricting the movement of the sheet S. As a result, the sheet S is smoothly pulled out from the main body housing 10 together with the paper feed cassette 110, and the remaining of the sheet S in the main body housing 10 is suppressed. Further, since the interlocking portion 50 is disposed on the main body housing 10 side, the positional accuracy of the interlocking portion 50 is maintained, and the position change of the pickup roller 112 is stably realized. Further, in this embodiment, a complicated mechanism is not provided on the paper feed cassette 110 side for moving the holder 20J (pickup roller 112), and the holder 20J is utilized by using the cassette right wall 110E of the paper feed cassette 110. Is realized.

  Further, in the present embodiment, in a state where the paper feed cassette 110 is mounted on the main body housing 10, the length of the horizontal portion of the protruding portion 110E5 in the mounting direction (see FIG. 5A) is the cassette front wall 110C and the pickup. It is set longer than the distance (see FIG. 5B) in the mounting direction (front-rear direction) with the shaft center of the roller 112. As a result, in the pulling-out operation of the paper feed cassette 110, the cassette front wall 110C is moved to the pickup roller before the front end portion (front end) in the mounting direction of the protrusion 110E5 passes through the contact piece 502 (FIG. 7A). It reaches the rear end side in the mounting direction from the axis 112 (FIG. 7B). In other words, the length of the horizontal portion of the protrusion 110E5 is set in advance so that the pickup roller 112 is surely disposed on the paper feed position side until the cassette front wall 110C comes out of the pickup roller 112. Has been. For this reason, the pickup roller 112 is continuously disposed on the sheet feeding position side until most of the sheet S whose leading end has reached the vicinity of the sheet feeding nip portion is pulled out forward of the pickup roller 112. Accordingly, the sheet S is pulled out from the main body housing 10 together with the paper feed cassette 110, and the remaining of the sheet S in the main body housing 10 is stably suppressed.

  8A is a side view of the paper feeding unit 20A and the paper feeding cassette 110 when the paper feeding cassette 110 is mounted in the main body housing 10 again, and FIG. 8B is a sectional view of the paper feeding unit 20A. As the paper feed cassette 110 is inserted (arrow D81 in FIG. 8A), the protrusion 110E5 presses the contact piece 502. At this time, the contact piece 502 is rotated in the direction opposite to that when the holder 20J is swung (FIG. 6A) (arrow D82 in FIG. 8A). In this case, since the push-up portion 503 is moved rearward from the protrusion 20K of the holder 20J, the holder 20J continues to be at the lower end of the pickup roller 112 by the engagement of the first hook piece 20F1 and the second hook piece 20F2. Stays in position. Thereafter, as described above, when the lift plate 111 is moved upward, the pickup roller 112 is pushed up by the sheet S, and the holder 20J is swung until the pickup roller 112 reaches the paper feeding position.

  Heretofore, the paper feeding unit 20 and the image forming apparatus 1 including the same according to the embodiment of the present invention have been described. According to the image forming apparatus 1 according to the present embodiment, the sheet S remaining in the main body housing 10 is suppressed. Further, since the interlocking portion 50 is disposed on the housing 20H side of the main body housing 10, the positional accuracy of the interlocking portion 50 is maintained, and the position change of the pickup roller 112 is stably realized. As a result, it is possible to stably form an image on the sheet S while suppressing sheet clogging in the main body housing 10. In addition, this invention is not limited to this, For example, the following modified embodiment can be taken.

  (1) In the above embodiment, the holder 20J and the interlocking portion 50 are described as being supported by the housing 20H in the main body housing 10, but the present invention is not limited to this. The holder 20 </ b> J and the interlocking unit 50 may be supported by different units in the main body housing 10. On the other hand, as described above, when the holder 20J and the interlocking unit 50 are supported by the same housing 20H, the swinging of the holder 20J and the movement of the pickup roller 112 are realized with high accuracy.

  (2) In the above-described embodiment, the mode in which the pickup roller 112 is moved from the lower end position to the paper feed position side in conjunction with the drawing operation of the paper feed cassette 110 has been described. In addition to this moving operation, when the paper feed cassette 110 starts to be pulled out, the retard roller 117 that forms the paper feed nip portion may be separated downward from the paper feed roller 113. With this configuration, even when the leading edge of the sheet S has entered the sheet feeding nip portion, the sheet S is stably pulled out from the main body housing 10 together with the sheet feeding cassette 110.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Main body housing (apparatus main body)
110 Paper feed cassette 110A Cassette bottom wall 110B Cassette front wall 110C Cassette front wall (front wall)
110D Cassette left wall 110E Cassette right wall (side wall)
110E1 Front end wall portion 110E2 First inclined portion 110E3 Horizontal portion 110E4 Second inclined portion 110E5 Protruding portion (protruding wall)
110S Sheet container 111 Lift plate 112 Pickup roller 113 Paper feed roller 113A Paper feed roller shaft (shaft)
117 retard roller 20 paper feed unit (paper feed device)
20A Paper feed unit 20F1 First hook piece 20F2 Second hook piece 20H Housing 20J Holder 20K Protrusion 22F Main conveyance path (sheet conveyance path)
30 Image forming unit 50 Interlocking unit (moving mechanism)
501 Shaft 502 Abutting piece 503 Push-up portion 504 Supported portion 505 Restricting portion 506 Ring portion

Claims (7)

The device body;
A sheet feeding cassette that is mounted toward the apparatus main body in a predetermined mounting direction and includes a sheet storage unit that stores sheets;
In the apparatus main body, the sheet accommodated in the sheet accommodating portion is conveyed in a sheet conveying direction along the mounting direction; and
In the apparatus main body, a pickup roller that is disposed to face the front end side in the mounting direction of the sheet stored in the sheet storage unit, is driven to rotate, and feeds the sheet in the sheet conveyance direction;
A sheet feeding roller that includes a shaft portion, is disposed downstream of the pickup roller in the sheet transport direction, is driven to rotate around the shaft portion, and transports the sheet in the sheet transport direction;
A retard roller disposed opposite to the paper feed roller and forming a nip portion through which the sheet passes with the paper feed roller;
One end portion is supported by the apparatus main body so as to be rotatable around the shaft portion, and the pickup roller comes into contact with the sheet stored in the sheet storage portion and feeds as the shaft rotates. A holder that rotatably supports the pickup roller at the other end so that the position can be changed between a possible paper feed position and a lower end position below the paper feed position;
The sheet storage unit is arranged to be able to move up and down, the sheets are stacked on the upper surface, and the pickup roller is swung while pushing up the pickup roller arranged at the lower end position with the upward movement. The holder is disposed at the sheet feeding position, and the holder is allowed to swing around the shaft portion as the lowering movement is performed, and the pickup roller is again disposed at the lower end position. A lifting plate for separating
A moving mechanism that is arranged in the apparatus main body and moves the pickup roller from the lower end position to the paper feeding position side in conjunction with a drawing operation of the paper feeding cassette from the apparatus main body;
A sheet feeding device comprising: The moving mechanism is rotatably supported by the apparatus main body,
When the sheet feeding cassette starts to be pulled out from the apparatus main body, the moving mechanism is rotated by the sheet feeding cassette, and the moving mechanism swings the holder so that the pickup roller is moved from the lower end position. The paper feeding device according to claim 1, wherein the paper feeding device moves to the paper feeding position side. The paper feed cassette includes a side wall including an upper surface portion and extending in the mounting direction,
The side wall includes a protruding wall having a predetermined length along the mounting direction, with a tip end side of the upper surface portion partially protruding upward.
The holder includes a protrusion,
The moving mechanism is
A shaft extending in the seat width direction intersecting the mounting direction and rotatably supported by the apparatus body;
A projecting piece extending in a radial direction from one end of the shaft, and a contact piece capable of contacting the projecting wall;
A push-up portion that protrudes radially from the other end side of the shaft and is engageable with the protrusion of the holder;
Have
In the mounted state of the sheet feeding cassette with respect to the apparatus main body, the contact piece is disposed at a standby position above the upper surface portion of the side wall on the rear end side in the mounting direction from the protruding wall
When the paper feeding cassette starts to be pulled out from the apparatus main body, the protruding wall interferes with the contact piece and presses the contact piece, so that the moving mechanism is rotated around the shaft while the push-up unit is rotated. The sheet feeding device according to claim 2, wherein the sheet abuts against the protrusion, pushes up the holder upward, and the pickup roller moves from the lower end position to the sheet feeding position side.   In the pulling-out operation of the paper feed cassette, when the protruding wall passes through the contact piece, the moving mechanism is rotated around the shaft by the weight of the holder, and the contact piece is again arranged at the standby position. The paper feeding device according to claim 3. The sheet feeding cassette is provided upright along the sheet width direction on the leading end side in the mounting direction, and includes a front wall that defines the leading end position of the sheet,
In the mounting state of the sheet feeding cassette with respect to the apparatus main body, the length of the protruding wall in the mounting direction is longer than the distance in the mounting direction between the front wall and the axis of the pickup roller. The paper feeding device according to claim 3 or 4. The sheet feeding cassette is provided upright along the sheet width direction on the leading end side in the mounting direction, and includes a front wall that defines the leading end position of the sheet,
In the drawer operation of the sheet feeding cassette, the front wall reaches the rear end side in the mounting direction from the axis of the pickup roller before the front end in the mounting direction of the protruding wall passes through the contact piece. The sheet feeding device according to claim 3 or 4, wherein A paper feeding device according to any one of claims 1 to 6,
An image forming unit that forms an image on a sheet conveyed by the paper feed roller;
An image forming apparatus.

Images