JP4924988B2 - Sheet conveying apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet conveying apparatus and an image forming apparatus.

  Patent Document 1 discloses a paper separation guide for a paper feed cassette that separates printing papers one by one. Japanese Patent Application Laid-Open No. 2004-228561 discloses a sheet supply device that is disposed on the downstream side of the sheet stacking unit and includes a separation slope that crawls the leading edge of the sheet fed by the sheet supply unit. Patent Document 3 discloses a recording apparatus that is disposed on the downstream side of the sheet feeding direction of the sheet stacking unit and includes a plurality of slope members that come into contact with a sheet fed by a sheet feeding roller and separate the sheet.

Patent No. 3692129 Japanese Patent No. 3762266 Japanese Patent No. 3870104

By the way, a general sheet conveying apparatus uses one surface of the sheet accommodating portion as a defining surface, aligns the leading end position (downstream position in the conveying direction) of the sheet, accommodates the sheet, and sequentially conveys the sheet downstream. Configured as follows. When the sheet conveying apparatus is configured as described above, a so-called rib may be provided from the viewpoint of reducing the frictional resistance between the sheet and the specified surface when conveying the sheet.
In such a sheet conveying apparatus, a relatively high contact pressure is generated in a portion that comes into contact with the rib, and the portion may be damaged. Such damage is caused when the user strongly presses the sheet against the specified surface when the sheet is accommodated, or repeatedly pressed against the specified surface when the sheet is sequentially conveyed downstream. It often occurs in some cases.

  SUMMARY An advantage of some aspects of the invention is to provide a sheet conveying apparatus and an image forming apparatus capable of accommodating a sheet in a sheet accommodating portion without damaging the sheet.

In order to achieve the above object, the present invention according to claim 1 is composed of a sheet storage unit that stores a sheet, a transport roll, and a winding means, and is positioned at the uppermost position among the sheets stored in the sheet storage unit. A conveying unit that acts so that only the sheet to be conveyed is conveyed , and a defining unit that defines a position of the sheet accommodated in the sheet accommodating unit on the conveying unit side , and the defining unit includes the sheet accommodating unit in the case where the sheet is accommodated, having one or more surface portions in contact with the surface of the conveying means side of the one side and a predetermined width of said sheet, and a protruding portion having a narrower width than the face portion, said The protruding portion is a sheet conveying device having a protruding amount smaller than that of the surface portion.

  The present invention according to a second aspect is the sheet conveying apparatus according to the first aspect, wherein the conveying roll includes a pickup roll and a supply roll.

  The present invention according to claim 3 is the sheet conveying apparatus according to claim 1 or 2, wherein the two surface portions are provided, and one surface portion and the other surface portion are in contact with one piece of the sheet within a range narrower than 210 mm. is there.

  According to a fourth aspect of the present invention, there is provided the sheet conveying apparatus according to the first or second aspect, wherein the two surface portions are provided, and one surface portion and the other surface portion are provided with an interval wider than 148 mm. .

  The present invention according to claim 5 is the sheet conveying apparatus according to claim 3 or 4, wherein the defining portion includes one or more protrusions between one surface portion and the other surface portion.

  The present invention according to claim 6 is an image forming apparatus having the sheet conveying apparatus according to any one of claims 1 to 5.

  According to the present invention, the sheet can be accommodated in the sheet accommodating portion without damaging the sheet.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 includes an image forming apparatus main body 12, an image forming unit 14 is mounted in the image forming apparatus main body 12, and a discharge unit 16 described later is provided on the upper part of the image forming apparatus main body 12. For example, a paper feed unit 18 and a manual paper feed unit 19 are disposed at the lower part of the image forming apparatus main body 12. Each of the sheet feeding unit 18 and the manual sheet feeding unit 19 has a function as a sheet conveying apparatus that conveys a sheet such as a sheet or an OHP sheet.

  The paper feed unit 18 includes a paper feed unit main body 20 and a paper feed cassette 22 that can store a plurality of sheets. A pickup roll 24 as a conveying member is disposed in the upper part near the rear end of the paper feed cassette 22, and a separating roll 26 and a supply roll 28 are disposed behind the pickup roll 24. The supply roll 28 is driven by a drive unit (not shown) and conveys the sheet toward a registration roll 38 to be described later. The separating roll 26 is pressed against the supply roll 28 and is configured to rotate in accordance with the rotation of the supply roll 28, and feeds the sheets one by one toward a later-described registration roll 38 together with the supply roll 28. For example, when a plurality of sheets are sandwiched between the supply roll 28 and the separation roll 26, the separation roll 26 causes a slip between the stacked sheets, and a sheet that is not in contact with the supply roll 28 is conveyed. This is prevented, the sheet is rolled, and only the uppermost sheet is sent to a registration roll 38 to be described later.

  The manual sheet feeding unit 19 includes a manual sheet feeding unit main body 30, a sheet storage unit 31 that can store a plurality of sheets, a separating roll 32 and a conveyance roll 33, which will be described later. A paper feed roll 34 as a transport roll is disposed in the upper part on the back side of the manual paper feed unit 19, and a transport roll 35 is disposed on the image forming apparatus main body 12 side behind the paper feed roll 34. By opening the front cover 68 that opens and closes a part of the front side (right side in FIG. 1) of the image forming apparatus 10, the sheet storage unit 31 can be accessed. The manual sheet feeding unit 19 is detachable from the image forming apparatus main body 12.

  The paper feed roll 34 is provided on the image forming apparatus main body 12 side, and is driven by a drive unit (not shown) to convey the sheet stored in the sheet storage unit 31 toward the image forming unit 14. The separating roll 32 is pressed against the sheet feed roll 34 and is rotatable in accordance with the rotation of the sheet feed roll 34, and cooperates with the sheet feed roll 34 to feed sheets one by one in the sheet conveying direction downstream. It acts so that it sends out toward between the conveyance roll 35 and the conveyance roll 33. For example, when a plurality of sheets are sandwiched between the sheet feeding roll 34 and the separating roll 32, the separating roll 32 causes a slip between the stacked sheets, and the sheet that the sheet feeding roll 34 is not in contact with. Is prevented from being conveyed, the sheet is rolled, and only the uppermost sheet is sent out between the conveying roll 35 and the conveying roll 33.

  The conveyance roll 35 is provided on the image forming apparatus main body 12 side, and is driven by a driving unit (not shown) so as to convey a sheet rolled by the separation roll 32 and the sheet supply roll 34 toward a registration roll 38 to be described later. Rotate. The conveyance roll 33 is pressed against the conveyance roll 35 and is rotatable in accordance with the rotation of the conveyance roll 35, and rotates so as to send the sheet toward the registration roll 38 together with the conveyance roll 35.

The main conveyance path 36 is a sheet path from the supply roll 28 to the discharge port 37, and the main conveyance path 36 is on the back side (the left side surface in FIG. 1) of the image forming apparatus main body 12. A fixing device 39, which will be described later, has a portion formed substantially vertically. A transfer device 42 and an image holding body 44, which will be described later, are arranged on the upstream side of the fixing device 39 in the main transport path 36, and a registration roll 38 is arranged on the upstream side of the transfer device 42 and the image holding body 44. The registration roll 38 temporarily stops the sheet supplied to the main conveyance path 36, aligns the leading end position, and conveys the sheet between the transfer device 42 and the image carrier 44 at a predetermined timing.
Further, a discharge roll 40 is disposed in the vicinity of the discharge port 37 of the main conveyance path 36.

  Accordingly, the sheet fed from the sheet feeding cassette 22 of the sheet feeding unit 18 by the pick-up roll 24 is turned by the cooperation of the separation roll 26 and the supply roll 28 and only the uppermost sheet is guided to the main conveyance path 36 to be registered. The developer image is temporarily stopped by the roll 38, and the developer image is transferred between a transfer device 42 and an image holding body 44, which will be described later, and the transferred developer image is fixed by the fixing device 39 and discharged. The paper is discharged from the discharge port 37 to the discharge unit 16 by the roll 40.

  Further, the sheet fed from the sheet storage unit 31 of the manual sheet feeding unit 19 by the sheet feeding roll 34 is turned only by the cooperation of the sheet rolling roll 32 and the sheet feeding roll 34 and is positioned at the uppermost position with the conveying roll 35. The developer image is guided between the transfer roller 33 and temporarily stopped by the registration roller 38, and the developer image is transferred between a transfer device 42 and an image holder 44, which will be described later, at a timing. The developer image is fixed by the fixing device 39 in the same manner as the fed sheet, and is discharged from the discharge port 37 to the discharge unit 16 by the discharge roll 40.

  However, in the case of duplex printing, it is returned to the reverse path. That is, the front side of the discharge roll 40 of the main transport path 36 is divided into two forks, a switching device 46 is provided at the divided part, and a reverse path 48 is formed from the divided part to the registration roll 38. . The reversing path 48 is provided with conveying rolls 50a to 50c. In the case of double-sided printing, the switching device 46 is switched to the side that opens the reversing path 48 and the discharge roll 40 is in front of the trailing edge of the sheet. Thus, the discharge roll 40 is reversed, the sheet is guided to the reverse path 48, and is discharged from the discharge port 37 to the discharge unit 16 through the registration roll 38, the transfer device 42, the image holding member 44, and the fixing device 39. .

  The image forming unit 14 is of, for example, an electrophotographic system, and is charged by an image holding member 44 such as a photosensitive member, a charging device 56 including a charging roll for uniformly charging the image holding member 44, and the charging device 56. An optical writing device 58 for writing a latent image on the image holding member 44 by light, a developing device 60 for visualizing the latent image of the image holding member 44 formed by the optical writing device 58 with a developer, and the developing device. A transfer device 42 such as a transfer roll that transfers the developer image by the sheet 60 to the sheet, a cleaning device 62 such as a blade that cleans the developer remaining on the image carrier 44, and the sheet transferred by the transfer device 42 And a fixing device 39 for fixing the developer image on the sheet. The optical writing device 58 is composed of, for example, a scanning type laser exposure device, and is disposed on the front side of the image forming apparatus main body 12 so as to be substantially parallel to the upper surface of the manual sheet feeding unit 19 described above. 44 is exposed.

  In the process cartridge 64, the image carrier 44, the charging device 56, the developing device 60, and the cleaning device 62 are integrated, and these can be replaced as a unit. The process cartridge 64 can be removed from the image forming apparatus main body 12 by opening the discharge unit 16.

Next, the manual sheet feeding unit 19 and its periphery will be described in detail.
2 to 5 show details of the manual sheet feeding unit 19. The manual sheet feeding unit 19 includes a manual sheet feeding unit main body 30, a sheet storage unit 31, a front cover 68, a separation roll 32, and a conveyance roll 33. A front cover 68 is provided on the front side (right side in FIG. 2) of the manual sheet feeding unit main body 30 to open and close the front side with the shaft portion 66 as a rotation axis. When the manual feed unit 19 is attached to the image forming apparatus main body 12, the front cover 68 opens and closes a part of the image forming apparatus main body 12. When the front cover 68 is opened, one surface located on the upper surface functions as a part of the sheet accommodating portion 31 and accommodates the sheet. The front cover 68 is opened to a position that forms a plane with the sheet storage portion 31 so that no load is generated on the stored sheet. The sheet storage unit 31 is provided with two conveyance guides 70 for reliably guiding the sheet in the conveyance direction substantially parallel to the sheet conveyance direction. The conveyance guide 70 is movable along a movable guide 72 provided substantially at right angles to the sheet conveyance direction, and is moved according to the size of the sheet stored in the sheet storage unit 31. Various sizes of sheets can be reliably guided in the transport direction. The bottom surface 29 of the manual sheet feeding unit 19 is configured to move up and down by being transmitted from the image forming apparatus main body 12 side. When the sheet is not conveyed toward the image forming unit 14, the sheet is moved downward about a point (not shown) on the front side of the manual sheet feeding unit main body 30 so that the sheet can be easily received. Further, when the sheet is conveyed toward the image forming unit 14, it moves upward so that the uppermost sheet is in contact with the paper feed roll 34.

A guide unit 74 is provided around the separation roll 32 and the conveyance roll 33. The guide part 74 has a defining surface 79 that defines the position of the leading edge of the stored sheet. When the sheet is stored in the sheet storing unit 31, the guide surface 74 is disposed downstream (conveyed). Two surface portions 76 that align the position of the sheet by making contact with a piece having a predetermined width by contacting a piece on the means side) and a plurality of protrusions (ribs) having a narrower width than the surface portion 76. And are provided. As shown in FIG. 5, the protrusion 78 has a smaller protrusion amount from the surface 79 to the seat side than the surface 76.
When the user accommodates the sheet, the sheet is aligned with the sheet by abutting against the defined surface 79. When the manual sheet feeding unit 19 is mounted on the image forming apparatus main body 12, the bottom surface 29 of the storage unit 31 is inclined toward the sheet feeding roll 34, and the position of the sheet is aligned by its own weight.

  In addition, the surface portion 76 has a width A shown in FIG. 3 narrower than 210 mm and a width B wider than 148 mm. A plurality of projecting portions 78 are arranged between the two surface portions 76 and on both outer sides (the end portion side of the sheet). Therefore, when the conveyance guide 70 is moved to a predetermined position, an A4 size sheet is inserted into the sheet storage unit 31 from the short side or the long side, and an A5 size or B5 size sheet is inserted from the long side. In such a case, the apex on the insertion direction side of the inserted sheet does not contact the surface portion 76. Therefore, the apex of the sheet that is easily deformed does not contact the defining surface 79. Further, when the conveyance guide 70 is moved to a predetermined position, an A5 size sheet is inserted into the sheet storage unit 31 from the short side, and a public postcard is inserted into the sheet storage unit 31 from the short side or the long side. In such a case, the sheet (including the postcard made by the government) is inserted so as to contact the protruding portion 78 without contacting the surface portion 76. In consideration of such a case, the protruding portion 78 is provided at a position that does not contact the apex on the insertion direction side of the inserted sheet.

Therefore, when a sheet having a predetermined width is inserted into the sheet accommodating portion 31, the sheet comes into contact with the surface portion 76 instead of the protruding portion 78. The surface portion 76 has a lower pressure per unit area on the sheet than the protruding portion 78. On the other hand, although the surface portion 76 has a larger frictional resistance to the sheet than the protruding portion 78, the ratio of the sheet contacting the surface portion 76 is smaller than the ratio of not contacting, and therefore does not hinder the conveyance of the sheet by the sheet feeding roll 34. The protruding portion 78 has a smaller amount of protrusion from the defining surface 79 than the surface portion 76, so that it is difficult to apply pressure to the sheet, and the friction resistance against the sheet is smaller than the surface portion 76. When the sheet is conveyed by the sheet feeding roll 34 or the like, every time the uppermost sheet is conveyed, the other sheet is pulled by the uppermost sheet and pressed against the regulation surface 79 side. The sheet is not easily damaged due to the low pressure. When the sheet is conveyed, the sheet is guided by contacting the surface portion 76 and the protruding portion 78 and the like. Further, since the bottom surface 29 of the manual feed unit 19 moves up and down each time the sheet is conveyed, one piece of the sheet is guided by the surface portion 76 and the protruding portion 76 at that time.
As described above, the surface portion 76 and the projecting portion 78 have a function of positioning the sheet when the sheet is accommodated in the sheet accommodating portion 31 and a function of guiding the conveyed sheet.

  Further, on both sides of the transport roll 33, there are provided rotatable transport rolls 80 that are in pressure contact with a transport roll (not shown) that rotates coaxially with the transport roll 35 and transports the sheet. The transport roll 33 is rotatably provided on a movable portion 84 that can move in the vertical direction along the vertical guide 82. The movable portion 84 is urged from below to above by an elastic member 86 such as a spring. The movable portion 84 is also provided with a plurality of protrusions 78 that guide the sheet.

  Therefore, the sheet picked up by the paper feed roll 34 is guided mainly between the paper feed roll 34 and the separating roll 32 by the surface portion 76, and is guided between the transport roll 35 and the transport roll 33 by the protruding portion 78. .

In the above embodiment, the manual sheet feeding unit 19 has been described as an example of the sheet conveying device. However, the present invention is not limited to this, and the sheet conveying device includes the sheet feeding cassette 22 like the sheet feeding unit 18. It may be a thing, and a paper may be accommodated temporarily and conveyed.
Moreover, in order to reduce the friction with the surface part 76 and the accommodated sheet, a film made of, for example, PET having slipperiness on the surface may be pasted. Further, in order to absorb the impact, an elastic material such as a sponge may be interposed between the film and the surface portion 76.

1 is a side view illustrating an outline of an image forming apparatus according to an embodiment of the present invention. FIG. 6 is a perspective view illustrating an outline of a manual sheet feeding unit. FIG. 3 is a top view illustrating an outline of a manual sheet feeding unit. 3 is a cross-sectional view illustrating an outline of a manual sheet feeding unit. FIG. It is an enlarged view which shows the surface part periphery of a guide part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 14 Image forming part 18 Paper feed unit 19 Manual paper feed unit 29 Bottom surface 30 Manual paper feed unit main body 31 Sheet storage part 32 Separating roll 33 Conveying roll 34 Supply roll 35 Conveying roll 68 Front cover 70 Conveying guide 72 Movable guide 74 Guide part 76 Surface part 78 Projection part 79 Regulation surface 84 Movable part 86 Elastic member

Claims (6)

A sheet accommodating portion for accommodating the sheet;
Conveying means composed of a conveying roll and a winding means, and acting so that only the uppermost sheet among the sheets accommodated in the sheet accommodating portion is conveyed,
A defining portion for defining a position on the conveying means side of the sheet accommodated in the sheet accommodating portion ;
Comprising
The defining part is:
If the sheet is accommodated in the sheet accommodating portion, and one or more surface portions in contact with the surface of the conveying means side of the one side and a predetermined width of said sheet,
A protrusion having a width narrower than the surface portion ;
Have
The protruding portion is a sheet conveying apparatus having a protruding amount smaller than that of the surface portion.   The sheet conveying apparatus according to claim 1, wherein the conveying roll includes a pickup roll and a supply roll.   The sheet conveying device according to claim 1, wherein two surface portions are provided, and one surface portion and the other surface portion are in contact with one piece of the sheet within a range narrower than 210 mm.   3. The sheet conveying apparatus according to claim 1, wherein two surface portions are provided, and one surface portion and the other surface portion are provided with an interval wider than 148 mm.   The sheet conveying apparatus according to claim 3, wherein the defining portion includes one or more protruding portions between one surface portion and the other surface portion.   An image forming apparatus comprising the sheet conveying device according to claim 1.

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