Sheet feed device for restricting noise generation, image forming apparatus
11292681 ยท 2022-04-05
Assignee
Inventors
Cpc classification
B65H2801/06
PERFORMING OPERATIONS; TRANSPORTING
B65H2404/62
PERFORMING OPERATIONS; TRANSPORTING
B65H2402/54
PERFORMING OPERATIONS; TRANSPORTING
B65H3/0661
PERFORMING OPERATIONS; TRANSPORTING
B65H3/5223
PERFORMING OPERATIONS; TRANSPORTING
International classification
B65H3/52
PERFORMING OPERATIONS; TRANSPORTING
B65H3/56
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A sheet feed device includes a pair of sheet feed rollers, a pair of separation pads, and a first contact portion. The pair of sheet feed rollers are provided in alignment with an interval between them in a width direction perpendicular to a feeding direction in which sheets placed on a sheet placing portion are fed, and feed a sheet from the sheet placing portion. When an overlapping sheet overlaps under a target sheet that is in contact with the pair of sheet feed rollers, the pair of separation pads separate the overlapping sheet from the target sheet. The first contact portion is provided on the holder at a position between the pair of separation pads and projecting more than contact surfaces of the pair of separation pads, and comes in contact with the lower surface of the sheet.
Claims
1. A sheet feed device comprising: a sheet placing portion in which a plurality of sheets are placed; a lift plate pivotably provided in the sheet placing portion to lift the sheets; a pair of sheet feed rollers provided in alignment with an interval therebetween in a width direction perpendicular to a feeding direction in which the sheets are fed, the pair of sheet feed rollers configured to feed a sheet from the sheet placing portion by contacting an upper surface of the sheet; a pair of separation pads provided in alignment with an interval therebetween in the width direction and biased toward the pair of sheet feed rollers, the pair of separation pads configured to, when an overlapping sheet overlaps under a target sheet that is in contact with the pair of sheet feed rollers, separate the overlapping sheet from the target sheet by coming in contact with a lower surface of the overlapping sheet; a holder provided in such a way as to move in a facing direction in which the pair of separation pads approach and separate from the pair of sheet feed rollers, the holder supporting the pair of separation pads; a first biasing member configured to bias the holder toward the pair of sheet feed rollers; a first contact portion provided on the holder at a position between the pair of separation pads and projecting more than contact surfaces of the pair of separation pads that come in contact with a lower surface of the sheet fed by the pair of sheet feed rollers, the first contact portion configured to come in contact with the lower surface of the sheet fed by the pair of sheet feed rollers; a pair of second contact portions located on both sides of the pair of separation pads in the width direction and projecting more than the contact surfaces of the pair of separation pads, the pair of second contact portions configured to come in contact with the lower surface of the sheet fed by the pair of sheet feed rollers; and a pair of second biasing portions configured to elastically bias the pair of second contact portions toward the pair of sheet feed rollers side in the facing direction, wherein the pair of second contact portions are supported by the holder in such a way as to move in the facing direction.
2. The sheet feed device according to claim 1, wherein the first contact portion includes an inclined surface that is inclined upward toward the downstream side in the feeding direction, and guides a front portion of the sheet toward the pair of sheet feed rollers, and each of the pair of second contact portions includes an inclined surface that guides the front portion of the sheet toward the pair of sheet feed rollers.
3. The sheet feed device according to claim 1, wherein the pair of separation pads abut on the pair of sheet feed rollers in an attitude where the contact surfaces are inclined upward toward the downstream side in the feeding direction.
4. An image forming apparatus comprising: the sheet feed device according to claim 1; and an image forming portion which forms an image on a sheet fed by the sheet feed device.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
DETAILED DESCRIPTION
(7) The following describes an embodiment of the present disclosure with reference to the accompanying drawings. It should be noted that the following embodiment is an example of a specific embodiment of the present disclosure and should not limit the technical scope of the present disclosure.
(8) [Configuration of Image Forming Apparatus 100]
(9) First, a description is given of a configuration of an image forming apparatus 100 according to an embodiment of the present disclosure with reference to
(10) For the sake of explanation, an up-down direction D1 is defined as a vertical direction in a state where the image forming apparatus 100 is installed usably (the state shown in
(11) The image forming apparatus 100 is a multifunction peripheral having a plurality of functions such as a scan function for reading image data from a document sheet, a print function for forming an image based on image data, a facsimile function, and a copy function. It is noted that the present disclosure is applicable to image forming apparatuses such as a printer device, a facsimile device, and a copier.
(12) As shown in
(13) The image reading portion 1 includes an automatic document feeder (ADF) that is configured to convey a document sheet placed on a document sheet placing portion to a sheet discharge portion. The image reading portion 1 also includes a document sheet table on which a document sheet is placed. The image reading portion 1 is configured to read image data from a document sheet conveyed by the automatic document feeder, or from a document sheet placed on the document sheet table.
(14) The image forming portion 2 is configured to form an image on a sheet by an electrophotographic method based on image data read by the image reading portion 1. In addition, the image forming portion 2 is configured to form an image on a sheet based on image data input from an external information processing apparatus. It is noted that the image forming portion 2 may form an image on a sheet by another image forming method such as an inkjet method.
(15) The operation/display portion 3 includes a display portion that is, for example, a liquid crystal display and displays various types of information in response to control instructions from a control portion (not shown). The operation/display portion 3 also includes an operation portion that is composed of, for example, operation keys or a touch panel through which various types of information are input to the control portion in response to user operations.
(16) [Configuration of Image Forming Portion 2]
(17) Next, a configuration of the image forming portion 2 is described with reference to
(18) As shown in
(19) The housing 10 stores the components of the image forming portion 2. The housing 10 is formed in an approximate shape of a rectangular parallelepiped. As shown in
(20) As shown in
(21) The image forming units 21 to 24 are arranged in line in a movement direction D4 (see
(22) The image forming unit 21 further includes a charging device, a developing device, a primary transfer roller, and a cleaning device in correspondence with the photoconductor drum 211. The charging device charges the surface of the photoconductor drum 211 to a certain potential. The developing device develops, with toner, an electrostatic latent image that is formed on the photoconductor drum 211 by the laser scanning unit 25. The primary transfer roller transfers a toner image that is formed on the photoconductor drum 211 by the developing device, to the intermediate transfer belt 26. The cleaning device cleans the surface of the photoconductor drum 211 after the toner image is transferred therefrom. It is noted that since the image forming units 22 to 24 are configured similar to the image forming unit 21, description thereof is omitted here.
(23) Toner containers 21A, 22A, 23A, and 24A (see
(24) The laser scanning unit 25 scans the photoconductor drums 211, 221, 231, and 241 with light based on image data. This allows an electrostatic latent image to be formed on the peripheral surface of each of the photoconductor drums 211, 221, 231, and 241 based on the image data.
(25) The intermediate transfer belt 26 is disposed above the photoconductor drums 211, 221, 231, and 241 so as to be in contact with the photoconductor drums 211, 221, 231, and 241. The intermediate transfer belt 26 is stretched by a driving roller and a plurality of stretching rollers. The intermediate transfer belt 26 moves in the movement direction D4 shown in
(26) The secondary transfer roller 27 transfers the toner images of the respective colors from the intermediate transfer belt 26 to a sheet supplied from the sheet feed portion 30.
(27) The sheet feed portion 30 supplies a sheet to the toner image transfer portion 20. As shown in
(28) The sheet feed cassette 31 stores sheets on which images are to be formed by the image forming portion 2. As shown in
(29) The first sheet feed unit 32 feeds the sheets stored in the sheet feed cassette 31 one by one to the first conveyance path 33. The first sheet feed unit 32 includes a pickup roller 321, a sheet feed roller 322, and a retard roller 323. The pickup roller 321 feeds a top sheet among the plurality of sheets lifted by the lift plate 311 of the sheet feed cassette 31, to the sheet feed roller 322 by rotating while in contact with an upper surface of the top sheet. The sheet feed roller 322 feeds the sheet fed by the pickup roller 321 to the first conveyance path 33 by rotating while in contact with the upper surface of the sheet. The retard roller 323 is disposed below the sheet feed roller 322 and biased toward the sheet feed roller 322. When a plurality of overlapping sheets are fed by the pickup roller 321, the retard roller 323 separates sheets other than the top sheet from the plurality of overlapping sheets.
(30) The first conveyance path 33 is a path in which a sheet moves from the sheet feed cassette 31 to the sheet receiving portion 10A. A plurality of conveyance rollers are provided in the first conveyance path 33. In addition, the secondary transfer roller 27 and the fixing portion 40 are provided in the first conveyance path 33. In the first conveyance path 33, a sheet that was fed from the sheet feed cassette 31 by the first sheet feed unit 32 is conveyed toward the sheet receiving portion 10A. The first conveyance path 33 is formed by a pair of conveyance guide members provided in the housing 10.
(31) A sheet(s) on which an image is to be formed by the image forming portion 2 is placed on the manual feed tray 34. The manual feed tray 34 is formed in an approximate shape of a flat, rectangular parallelepiped, and is hollow inside. The manual feed tray 34 is provided in such a way as to open and close the opening portion 10B. Specifically, the manual feed tray 34 includes a rotation shaft 34A (see
(32) As shown in
(33) As shown in
(34) The second sheet feed unit 35 feeds, one by one, the one or more sheets S (see
(35) The second conveyance path 36 is a path in which a sheet moves from the manual feed tray 34 to the first conveyance path 33. In the second conveyance path 36, a sheet fed from the manual feed tray 34 by the second sheet feed unit 35 is conveyed toward the first conveyance path 33. The second conveyance path 36 is formed by a pair of conveyance guide members provided in the housing 10.
(36) The fixing portion 40 fixes a toner image that was transferred to a sheet by the secondary transfer roller 27, to the sheet by heating the toner image. The sheet with the toner image fixed thereto is discharged to the sheet receiving portion 10A.
(37) [Configuration of Second Sheet Feed Unit 35]
(38) Next, a description is given of a configuration of the second sheet feed unit 35 with reference to
(39) As shown in
(40) As shown in
(41) As shown in
(42) The pad holding portion 57 supports the pair of separation pads 54. The pad holding portion 57 is supported by the housing 10 so as to move in a facing direction D8 shown in
(43) The pair of separation pads 54 are configured to, when a sheet (an overlapping sheet) overlaps under a sheet (target sheet) that is in contact with the pair of sheet feed rollers 51, separate the overlapping sheet from the target sheet by coming in contact with a lower surface of the overlapping sheet. That is, the pair of separation pads 54 separate the overlapping sheet from the target sheet by a frictional force acting between the pair of separation pads 54 and the overlapping sheet. This prevents a plurality of sheets from being fed, in a state of being overlapped with each other, from the manual feed tray 34.
(44) Meanwhile, a friction between a sheet S and the pair of separation pads 54 may cause the sheet S to vibrate, and the vibration may generate a noise.
(45) There is known a related technology in which two types of separation pads having different friction coefficients are disposed in alignment in the feeding direction D7 so as to restrict the noise due to the friction between the sheet and the separation pads from being generated.
(46) However, in a sheet feed device according to the above-mentioned related technology, the configuration of the separation pads is complicated.
(47) On the other hand, as described below, in the image forming apparatus 100 according to the embodiment of the present disclosure, the configuration of the pair of separation pads 54 is not complicated, and the noise due to the friction between the sheet and the pair of separation pads 54 is prevented from being generated.
(48) Specifically, as shown in
(49) As shown in
(50) In a state where the sheet S is sandwiched by the pair of sheet feed rollers 51 and the pair of separation pads 54 at both sides of the center of the sheet S in the front-rear direction D2, the center of the sheet S is pressed upward by the intermediate contact portion 61. This allows an undulation waving in the front-rear direction D2 to be formed at the center of the sheet S in the front-rear direction D2, resulting in the sheet S having high stiffness. When the sheet S has high stiffness, vibration of the sheet S due to a friction between the lower surface of the sheet S and the pair of separation pads 54 is restricted. As a result, generation of noise due to the friction between the sheet S and the pair of separation pads 54 is restricted.
(51) As shown in
(52) As shown in
(53) In the state where the sheet S is sandwiched by the pair of sheet feed rollers 51 and the pair of separation pads 54 at both sides of the center of the sheet S in the front-rear direction D2, two end portions of the sheet S at opposite ends in the front-rear direction D2 are pressed upward by the pair of lateral contact portions 62. This allows undulations waving in the front-rear direction D2 to be formed at the opposite ends in the front-rear direction D2 of the sheet S, resulting in the sheet S having high stiffness. As a result, generation of noise due to the friction between the sheet S and the pair of separation pads 54 is restricted.
(54) As shown in
(55) The pair of lateral contact portions 62 are supported by the pad holding portion 57 in such a way as to move in the facing direction D8 (see
(56) The pair of compression coil springs 65 elastically bias, toward the pair of sheet feed rollers 51 side in the facing direction D8, the pair of lateral contact portions 62 that are supported in such a way as to move in the facing direction D8. As shown in
(57) It is noted that the pad holding portion 57 may not include the pair of compression coil springs 65. In addition, the pad holding portion 57 may include, in place of the pair of compression coil springs 65, an elastic member that is configured to bias the pair of lateral contact portions 62. In addition, the pad holding portion 57 may not include either or both of the lateral contact portions 63 and 64. In addition, the intermediate contact portion 61 and the pair of lateral contact portions 62 may be roller members that are supported in such a way as to be rotatable around an axis that extends in the front-rear direction D2.
(58) In addition, the present disclosure may be applied to the sheet feed cassette 31 and the first sheet feed unit 32. That is, the first sheet feed unit 32 may be configured similar to the pair of sheet feed rollers 51, the pair of separation pads 54, and the pad holding portion 57, instead of including the pickup roller 321, the sheet feed roller 322, and the retard roller 323. In this case, the sheet feed cassette 31 is another example of the sheet placing portion of the present disclosure.
(59) It is to be understood that the embodiments herein are illustrative and not restrictive, since the scope of the disclosure is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof are therefore intended to be embraced by the claims.