Patent Application
20170137244
This application is based upon, and claims the benefit of priority from, corresponding Japanese Patent Application No. 2015-225586 filed in the Japan Patent Office on Nov. 18, 2015, the entire contents of which are incorporated herein by reference.
Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
A typical image forming apparatus, such as a copier and a printer, may be configured such that mounting an attachable/detachable sheet feed cassette pushes up a separation roller, which is supported by an apparatus main body, to be positionally aligned.
Another image forming apparatus may be configured such that mounting an attachable/detachable sheet feed cassette pushes up a duplex conveyance unit, which is supported by an apparatus main body, to be positionally aligned. The duplex conveyance unit includes a fixed guide and a movable guide. The fixed guide is secured to the apparatus main body. The movable guide is turnably supported below the fixed guide. This duplex conveyance unit allows a paper jam to be fixed such that the movable guide is turned downward after the sheet feed cassette is extracted, so as to cause a duplex conveying path to be opened.
This image forming apparatus includes a projection piece projecting downward and an abutment portion on which the projection piece is brought into abutment. The projection piece is formed on the movable guide, and the abutment portion is formed in the sheet feed cassette. Mounting the sheet feed cassette brings the abutment portion into abutment on the projection piece, so as to cause the movable guide to be lifted by the sheet feed cassette, thus positionally aligning the movable guide with respect to the fixed guide. Thus, the movable guide and the fixed guide are positionally aligned to cause respective conveyance rollers located in the movable guide and the fixed guide to be brought into abutment one another with appropriate pressure. This causes a paper sheet to be smoothly conveyed along the duplex conveying path.
An image forming apparatus according to one aspect of the disclosure includes an apparatus main body, a sheet feed cassette, and a conveyance unit. The sheet feed cassette is attachably/detachably supported by the apparatus main body. The conveyance unit includes a conveying path formed above the sheet feed cassette. The conveying path conveys sheet in a predetermined direction. The conveyance unit includes a fixed guide, a movable guide, and conveyance rollers. The fixed guide is secured to the apparatus main body. The movable guide is turnably supported around one end thereof in a sheet conveyance direction below the fixed guide. The conveyance rollers are provided in each of the fixed guide and the movable guide. The conveyance rollers rotate in pressure abutment with the one another to convey sheet along the conveying path. The conveying path is provided to be openable by the movable guide being turned downward after the sheet feed cassette is extracted from the apparatus main body. The fixed guide includes an engaged portion provided on one side of the conveyance unit in a sheet width direction intersecting the conveyance direction. The movable guide includes an engaging portion engageable with the engaged portion provided on the one side of the movable guide in the sheet width direction. The sheet feed cassette includes a first and a second pressing portions provided on both sides thereof in the sheet width direction. The movable guide further includes a first and a second pressed portions provided on both sides thereof in the sheet width direction. By the first and the second pressed portions abutting on the first and the second pressing portions, the movable guide is pushed up by the sheet feed cassette, and the movable guide is positionally aligned with respect to the fixed guide. The second pressing portion is provided on another side of the sheet feed cassette in the sheet width direction and includes an adjusting mechanism that adjusts pressing force against the second pressed portion to enable adjustment of pressure abutment force between the conveyance rollers.
These as well as other aspects, advantages, and alternatives will become apparent to those of ordinary skill in the art by reading the following detailed description with reference where appropriate to the accompanying drawings. Further, it should be understood that the description provided in this summary section and elsewhere in this document is intended to illustrate the claimed subject matter by way of example and not by way of limitation.
Example apparatuses are described herein. Other example embodiments or features may further be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. In the following detailed description, reference is made to the accompanying drawings, which form a part thereof.
The example embodiments described herein are not meant to be limiting. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the drawings, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.
The following describes an image forming apparatus according to one embodiment of the disclosure with reference to the drawings.
First, with reference to
The printer 1 includes an apparatus main body 2 having a box shape. The apparatus main body 2 includes a hollow portion surrounded with a bottom plate 2a, a top panel 2b, a left side plate 2c, a right side plate 2d, a front side plate 2e, and a rear side plate 2f. The top panel 2b includes a sheet discharge tray 4 inclined upward toward a front from a rear. At a rear of the sheet discharge tray 4, a sheet discharge exit 5 is formed.
The hollow portion has a lower portion housing a sheet feed cassette 7 that houses paper sheets. The sheet feed cassette 7 includes a housing portion 7a and a front wall portion 7b. The housing portion 7a houses the paper sheets. The front wall portion 7b includes a lower portion of the front side plate 2e of the apparatus main body 2. Sliding the sheet feed cassette 7 in the front-rear direction ensures the sheet feed cassette 7 to be attachable/detachable to/from the apparatus main body 2. Above a front of the sheet feed cassette 7, a paper feeder 8 that feeds the paper sheet from the sheet feed cassette 7 is located. The paper feeder 8 includes a pickup roller 9, a feed roller 10, and a retard roller 11 opposed to the feed roller 10.
Above the sheet feed cassette 7, an image forming unit 13 is located. In the image forming unit 13, a photoreceptor drum 14 is rotatably located. A charger 15, a developing device 16, a transfer roller 17, and a cleaning apparatus 18 are located around the photoreceptor drum 14 along a rotation direction of the photoreceptor drum 14. Above the developing device 16, a toner container 19 is attachably/detachably mounted. Between the transfer roller 17 and the photoreceptor drum 14, a transfer nip 20 is formed. Above the image forming unit 13, an exposure device 21 constituted of a laser scanning unit (LSU) is located. Furthermore, behind the image forming unit 13, a fixing unit 22 is located, and above the fixing unit 22, a discharge unit 23 facing the sheet discharge exit 5 is located.
The apparatus main body 2 internally includes a main conveying path 25. The main conveying path 25 is a path for the paper sheet conveyed toward the discharge unit 23 after the paper sheet passes through the transfer nip 20 and the fixing unit 22 from the paper feeder 8. In the main conveying path 25, a conveyance roller 26 is located in a downstream side of the paper feeder 8, and a registration roller pair 27 is located in a downstream side of the conveyance roller 26.
Furthermore, between the sheet feed cassette 7 and the image forming unit 13, a duplex conveyance unit 30 is located. In the duplex conveyance unit 30, a duplex conveying path 32 is formed. The duplex conveying path 32 is provided toward an outlet 30b formed in a front end portion of the duplex conveyance unit 30 from an inlet 30a formed in a rear end portion of the duplex conveyance unit 30. The duplex conveyance unit 30 includes the inlet 30a connected to a branch path 34 branching from the main conveying path 25 in a downstream side of the fixing unit 22. The duplex conveyance unit 30 further includes the outlet 30b connected to a connecting path 35 connecting to the main conveying path 25 in an upstream side of the conveyance roller 26.
Next, the following describes an image forming operation of the printer 1 having such configuration. In the image forming unit 13, after the charger 15 charges a surface of the photoreceptor drum 14, a laser beam from the exposure device 21 exposes the photoreceptor drum 14 corresponding to image data to form an electrostatic latent image on the surface of the photoreceptor drum 14. The developing device 16 develops the electrostatic latent image into a toner image.
ON the other hand, after the paper sheet conveyed from the sheet feed cassette 7 by the paper feeder 8 is conveyed to the transfer nip 20 along the main conveying path 25 in accordance with timing of the above-described image forming operation, the toner image on the photoreceptor drum 14 is transferred onto the paper sheet in the transfer nip 20. Subsequently, the paper sheet onto which the toner image has been transferred is conveyed to a downstream side of the main conveying path 25. After the paper sheet is conveyed into the fixing unit 22, the fixing unit 22 fixes the toner image on the paper sheet. The paper sheet onto which the toner image has been fixed passes through the sheet discharge exit 5 from the discharge unit 23 to be discharged to the sheet discharge tray 4. The cleaning apparatus 18 removes remaining toner on the photoreceptor drum 14.
When performing duplex printing, the paper sheet, on one surface of which the toner image is formed after the paper sheet has passed through the fixing unit 22, is reversely conveyed after the discharge unit 23 discharges a front end portion of the paper sheet from the sheet discharge exit 5. Then, a rear end portion of the paper sheet passes through the branch path 34 first, which causes the paper sheet to be conveyed to the duplex conveying path 32. A branch guide (not illustrated) is located in a downstream side in a conveyance direction of the fixing unit 22. The branch guide guides the front end portion of the paper sheet to the sheet discharge exit 5 during ordinary printing, and guides the rear end portion of the paper sheet to the branch path 34 during duplex printing. Subsequently, the paper sheet passes through the connecting path 35 to be conveyed along the main conveying path 25 again, and the image forming unit 13 similarly forms a toner image on the other surface. Then, after the fixing unit 22 fixes the toner image, the discharge unit 23 discharges the paper sheet to the sheet discharge tray 4.
Next, with reference to
As illustrated in
In the fixed guide 41, a drive roller 45 is supported to project toward the duplex conveying path 32 and rotate. As schematically illustrated in
Furthermore, as illustrated in
As illustrated in
As illustrated in
Furthermore, two driven rollers 53 are supported to project to the duplex conveying path 32 and to rotate on the movable guide 42. As illustrated in
Furthermore, as illustrated in
As illustrated in
The bearing portions, which are located in the rear end portion of the movable guide 42, are pivotally supported by the respective spindles of the fixed guide 41. This causes the movable guide 42 to be turnably supported with respect to the fixed guide 41. Holding the handle 51 to turn the movable guide 42 in an upper direction brings the protrusion 55 formed on the movable guide 42 into abutment on a lower edge portion 47a of the opening 47 on the fixed guide 41. After that, the protrusion 55 is internally pressed by the lower edge portion 47a, which causes an elastic deformation of the protrusion 55. Then, as illustrated in
Next, with reference to
As illustrated in
The housing portion 7a has right and left side plates at which the right pressing portion 62 and a left pressing portion 61 are formed at front end portions of top surfaces in the housing portion 7a. The right pressing portion 62 and the left pressing portion 61 are brought into abutment on the right and left projection pieces 58 located in the movable guide 42 to push up the right and left projection pieces 58, respectively.
As illustrated in
As illustrated in
As illustrated in
As illustrated in
The eccentric cam 68 is supported between the inner and outer sidewall portions 67 by an operation member 71. The operation member 71 includes a handle portion 72 and a spindle portion 73. The handle portion 72 has a disk shape. The spindle portion 73 is located upright on the center of the handle portion 72. The spindle portion 73 has a D-shaped cross section and is engageable with the D cutout 69 on the eccentric cam 68. After the spindle portion 73 in the operation member 71 passes through the D cutout 69 on the eccentric cam 68 through the shaft hole 67c of the outer sidewall portion 67, the spindle portion 73 passes through the shaft hole 67c of the inner sidewall portion 67 to prevent the spindle portion 73 from falling out. This causes the eccentric cam 68 to be supported between the inner and outer sidewall portions 67 and to be rotatable about the spindle portion 73 by the operation member 71. The outer sidewall portion 67 includes the concave portion 67b that houses the handle portion 72 on the operation member 71. During a normal operation, the eccentric cam 68 is supported by the operation member 71 such that the second outer peripheral surface 68b becomes the top surface. The inner and outer sidewall portions 67 have the upper end portions 67a projecting upward with respect to the eccentric cam 68.
The following describes a mounted state of the duplex conveyance unit 30 and the sheet feed cassette 7 in the printer 1 with the above-described configuration with reference to
When the sheet feed cassette 7 is mounted in the apparatus main body 2 after the protrusion 55 of the movable guide 42 in the duplex conveyance unit 30 is engaged with the opening 47 on the fixed guide 41, the right and left pressing portions 62 and 61, which are formed in the sheet feed cassette 7, are brought into abutment on the respective right and left projection pieces 58, which are formed on the movable guide 42 in the duplex conveyance unit 30, from a lower side. That is, as illustrated in,
Thus, the right and left projection pieces 58 are brought into abutment on the right and left pressing portions 62 and 61, respectively. This causes the movable guide 42 to be pushed up by the sheet feed cassette 7, thus positionally aligning the movable guide 42 with respect to the fixed guide 41. The sheet feed cassette 7 is positionally aligned in the apparatus main body 2 with high accuracy to ensure paper feeding performance of the paper feeder 8. This also ensures the positionally aligning of the movable guide 42 with high accuracy due to the pushing up by the sheet feed cassette 7. As illustrated in
As described above, in the right pressing portion 62, the lower end surface of the right projection piece 58 in the movable guide 42 is brought into abutment on the second outer peripheral surface 68b in the eccentric cam 68 one another. Since the eccentric cam 68 is rotatably supported by the operation member 71 between the inner and outer sidewall portions 67, holding the handle portion 72 on the operation member 71 to rotate the spindle portion 73 rotates the eccentric cam 68 along with the operation member 71. Then, this moves a position on which the lower end surface of the right projection piece 58 is brought into abutment along the circumferential direction, thus changing the height of the lower end surface of the right projection piece 58.
The following describes the height change of the lower end surface of the right projection piece 58 due to the rotation of the eccentric cam 68 with reference to
In a normal state illustrated in
Thus, the height change of the lower end surface of the right projection piece 58 changes, as illustrated in
The movable guide 42 and the fixed guide 41 are engaged by an engagement between the protrusion 55 and the opening 47, which are formed on respective left side plates of the movable guide 42 and the fixed guide 41, and the left projection piece 58 in the movable guide 42 is positionally aligned with respect to the abutting surface 65 in the left pressing portion 61. This holds the approximately-identical pressure abutment force between the roller portions 53b of the left-side driven rollers 53 in the movable guide 42 and the left-side roller portions 45b of the drive roller 45 in the fixed guide 41.
On the other hand, the movable guide 42 and the fixed guide 41 do not engage at a right side. As described above, in the right pressing portion 62, the height to which the movable guide 42 is pushed up by the sheet feed cassette 7 is changeable. That is, the pressure abutment forces between the roller portions 53b of the right-side driven rollers 53 in the movable guide 42 and the right-side roller portions 45b of the drive roller 45 in the fixed guide 41 are changeable.
Consequently, if an oblique feeding of the paper sheet occurs in the duplex conveying path 32, turning of the operation member 71 in the right pressing portion 62 ensures the adjustment of the pressure abutment force between the roller portions 53b of the right-side driven rollers 53 in the movable guide 42 and the right-side roller portions 45b of the drive roller 45 in the fixed guide 41. This fixes the oblique feeding of the paper sheet. Specifically, turning the operation member 71 in anticlockwise direction illustrated in
As described above, in the printer 1 of the disclosure, operating the operation member 71 in the sheet feed cassette 7 to rotate the eccentric cam 68 ensures the adjustment of the pressure abutment force between the respective roller portions 45b of the drive roller 45 and the respective roller portions 53b of the driven rollers 53 in the paper sheet width direction. Thus, if an oblique feeding of the paper sheet occurs in the duplex conveying path 32, the oblique feeding of the paper sheet is fixed with a simple mechanism and an easy method where the operation member 71 is held to rotate the eccentric cam 68 so as to appropriately adjust the pressure abutment force.
Furthermore, the inner and outer sidewall portions 64, which are formed in the left pressing portion 61 in the sheet feed cassette 7, regulate the left projection piece 58 in the movable guide 42 to prevent a movement to the paper sheet width direction from the abutting surface 65. This ensures the stable abutment of the left projection piece 58 and the abutting surface 65. The upper end portions 67a on the inner and outer sidewall portions 67, which are formed in the right pressing portion 62 in the sheet feed cassette 7, regulate the right projection piece 58 in the movable guide 42 to prevent a movement to the paper sheet width direction from the outer peripheral surface of the eccentric cam 68. This ensures the stable abutment of the right projection piece 58 and the eccentric cam 68.
Consequently, even when the printer 1 receives an impact and a vibration during storage and conveyance, the right and left projection pieces 58 in the movable guide 42 do not separate from the right and left pressing portions 62 and 61, which are in the sheet feed cassette 7. That is, the abutment states of the respective right and left projection pieces 58 and the right and left pressing portions 62 and 61 are maintained. This causes the sheet feed cassette 7 to push up the movable guide 42 for appropriately maintaining the positional relationship between the fixed guide 41 and the movable guide 42. In a state where the sheet feed cassette 7 is mounted, the positions of the right and left projection pieces 58 and the positions of the right and left pressing portions 62 and 61 are not approximately displaced in the paper sheet conveyance direction. This does not cause the right and left projection pieces 58 to move in the paper sheet conveyance direction to separate from the right and left pressing portions 62 and 61.
Both the right pressing portion 62 and the left pressing portion 61 do not have to include the inner and outer sidewall portions 67 and the inner and outer sidewall portions 64. It is possible that only the right pressing portion 62 includes the inner and outer sidewall portions 67. In this case, the sheet feed cassette 7 is smoothly mounted with the reduced interference between the movable guide 42 when mounting the sheet feed cassette 7. If a lift mechanism (not illustrated) in an elevating plate (not illustrated) on which the paper sheets are liftably placed is located at a right side of the sheet feed cassette 7, this makes a space outside in the paper sheet width direction of the right projection piece 58. The space causes a problem that the right projection piece 58 is easily dropped from the right pressing portion 62. Thus, only the right pressing portion 62 includes the inner and outer sidewall portions 67 to prevent the right projection piece 58 from dropping.
While in the embodiment the right projection piece 58 is configured to be brought into abutment on the eccentric cam 68 in the right pressing portion 62, the left projection piece 58 may be configured to be brought into abutment on the eccentric cam 68 in the left pressing portion 61. The eccentric cam 68 may have the outer peripheral surface with an appropriately-changed shape.
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-225586 | Nov 2015 | JP | national |
