JP2005263395A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus, surely removing powder such as paper dust and fibrous foreign matter staying at the tip of a member for cleaning a paper transport roller. <P>SOLUTION: The tip of a paper dust removing member 42 is pressed to the surface of a registration driven roller 11b, and paper dust or the like adhering to the surface of the roller is scraped off by reverse rotation of the registration driven roller 11b to be stored in space formed between a paper dust removing member support plate 43 and a paper dust collecting case 44 by utilizing the gravity. After the end of image forming operation in an image forming part, the registration driven roller 11b is reversed to remove powder material p such as paper dust staying at the tip of a paper dust removing member 42 and fibrous foreign matter f caught in the member are removed from the tip of the paper dust removing member 42 not to exert any influence upon the image formation in the image forming part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, and a printer, and more particularly to a paper feed function thereof.

  In an image forming apparatus such as a copying machine, when paper is conveyed to an image forming unit by a pair of registration rollers, paper dust may adhere to the registration rollers and accumulate. The adhesion of paper dust to the registration rollers decreases the coefficient of friction between the registration roller pairs and causes a decrease in paper conveyance force. Further, when paper dust or the like adhering to the registration roller moves to the image forming unit, it may cause an abnormal image.

  Therefore, an image forming apparatus that can remove and collect paper dust and the like has been proposed. For example, there is a type in which a cleaning blade is brought into contact with the surface of a registration roller, and paper dust and other objects attached as the registration roller pair rotates are physically peeled off.

Japanese Patent Laid-Open No. 10-129874

  However, if the state in which the paper dust is strongly pressed against the tip of the cleaning blade continues, the paper dust may harden and adhere to the cleaning blade, which may cause a reduction in the performance of removing paper dust and the like. In addition, fibers or fibrous materials (hereinafter referred to as fibrous materials) including paper dust may accidentally enter between the cleaning blade and the registration roller and get caught on the tip of the cleaning blade. When the state occurs, a gap is formed between the cleaning blade and the registration roller around the caught fibrous material, and powder such as paper dust may slip through from there.

  In view of the above-described conventional problems, the present invention can surely remove powder and other foreign matters such as paper dust accumulated at the tip of a member for cleaning a roller for conveying paper, and always has good cleaning performance. An object of the present invention is to provide an image forming apparatus which can be maintained.

  An apparatus for removing paper dust or the like of an image forming apparatus according to claim 1 of the present invention removes powdery substances such as paper dust or fibrous foreign matters attached to a pair of conveying rollers for conveying paper to an image forming unit, In a paper dust removal device of an image forming apparatus having a removing member that slides and removes one of the transport roller pairs, the transport roller pair is moved to the image forming section after the image forming operation in the image forming section is completed. The sheet is rotated in the direction opposite to the rotation direction at the time of conveying the sheet.

  According to a second aspect of the present invention, in the paper dust removal device of the image forming apparatus of the first aspect, the reverse rotation of the pair of transport rollers is caused by the contact portion of the one transport roller with the removal member. This is performed in a range that does not return from the position to the nip position of the conveying roller pair.

  According to a third aspect of the present invention, there is provided a paper dust removing device of the image forming apparatus according to the first aspect, wherein the paper dust or the like is removed by the removing member, and a storage portion for collecting powdery foreign matters such as paper dust or the like is collected. A seal member that seals the storage portion at a position away from the removal member, and the contact portion of the one transport roller with the removal member is sealed by the seal member. It is characterized in that it is performed within a range that does not reach the site.

  According to a fourth aspect of the present invention, there is provided an image forming apparatus according to any one of the first to third aspects, wherein the paper dust removing device of the image forming apparatus is used as a paper dust removing device for a pair of paper transport rollers. Features.

  According to the fifth aspect of the present invention, the paper dust removal device of the image forming apparatus according to any one of claims 1 to 3 is used as a paper dust removal device for a pair of registration rollers.

  Since the present invention reverses the conveying roller pair after the image forming operation is completed, it is possible to remove paper dust and fibrous foreign matter accumulated at the tip of the removing member, and always maintain good cleaning performance.

  The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings.

  FIG. 1 is a schematic cross-sectional view of an example of an image forming apparatus to which the present invention is applied. In FIG. 1, reference numeral 1 denotes an image forming apparatus main body, which has an image forming unit 2 therein, has a photosensitive drum 3, and forms an image based on a known electrophotographic process. Below the image forming unit 2, a paper feeding unit 4 having two-stage paper feeding cassettes 4 a and 4 b for feeding transfer paper is provided. In the figure, 5 is a manual paper feed unit, 6 is a duplex unit for reversing the front and back of the paper, 7 is a transfer belt, 8 is a fixing roller pair, and 9 is a paper discharge roller pair. Reference numeral 10 denotes a conveyance roller, and 11 denotes a registration roller pair including a pair of registration rollers.

  In this image forming apparatus, the paper fed from the paper feeding unit 4 or the manual paper feeding unit 5 is sent to the registration roller pair 11 via the transport roller 10 and the toner formed in the image forming unit 2 by the registration roller pair 11. The image and timing are conveyed to the transfer unit. The transfer unit includes a transfer belt 7, which transfers an unfixed toner image onto a sheet sent to the transfer unit, and further downstream in the transport direction (upward in the illustrated example) as the transfer belt 7 travels. The sheet is conveyed to the fixing roller pair 8 positioned and is nipped by the fixing roller pair 8. The fixing roller pair 8 fixes the unfixed toner image on the paper by heating and pressurizing the paper to be conveyed while being sandwiched, and further conveys the toner image upward.

  Above the fixing roller pair 8, a switching claw 12 for selectively switching the sheet transport destination between the paper discharge roller pair 9 and the duplex unit 6 is disposed. The switching claw 12 guides the paper to the paper discharge roller 9 or guides it to the duplex unit 6 by switching its position.

  In the duplex unit 6, a reversing claw 13 is disposed near the entrance, and a reversing roller 14 is provided following the reversing claw 13. The paper transported to the duplex unit 6 by switching the transport direction by the switching claw 12 is first sent to the switchback path 15 by switching the transport path by the reversing claw 13, and is reversed when the rear end of the paper passes through the reversing claw 13. While switching the position of the nail, the reverse roller 14 starts reverse rotation. By this switching, the sheet passes through the double-sided unit conveyance path 16 with the rear end side so far as the leading side, and is again sent to the registration roller pair 11. At this time, since the front and back sides of the sheet are reversed, an image is also formed on the back side.

  FIG. 2 is an enlarged cross-sectional view showing a main part of one embodiment of the present invention. In this figure, the registration roller pair 11 is indicated by registration rollers 11a and 11b. In the figure, reference numeral 20 denotes a lower guide plate, 21 denotes an upper guide plate, and the guide plates 20 and 21 guide the paper to the nip portion of the registration rollers 11a and 11b constituting the registration roller pair 11. On the upper guide plate 21, there is provided a paper dust removing member support plate 43 provided with a paper dust removing member 42 adhered thereto, and a paper dust collecting case 44 is detachably disposed on the upper side thereof. It constitutes a paper dust collection unit. In the illustrated example, the registration roller 11a is a driving roller and the registration roller 11b is a driven roller, and a paper dust collecting unit is provided for the registration driven roller 11b. However, the present invention is not limited to this and is possible. If so, it may be provided on the resist driving roller 11a side.

  The tip of the paper dust removing member 42 is pressed against the surface of the resist driven roller 11b, and the resist driven roller 11b is rotated clockwise in FIG. 2 to scrape off paper dust and the like adhering to the surface and use gravity. Thus, it accumulates in a space formed between the paper dust removing member support plate 43 and the paper dust collecting case 44.

  For the paper dust removing member 42, a polyester film material having a thickness of about 0.1 mm to 0.3 mm is optimal. A shield member 45 for preventing the scattering of paper dust is adhered to one end of the paper dust collecting case 44, and a slight gap is provided between the tip of the shield member 45 and the surface of the resist driven roller 11b. This prevents the powder from adhering and prevents the recovered paper dust from coming out of the paper dust recovery case 44.

  3 and 4 are enlarged views showing a phenomenon occurring on the surface of the resist driven roller 11b and the tip of the paper dust removing member 42, and are enlarged views of a portion A in FIG. When the resist driven roller 11b rotates clockwise in the drawing, the powdery substance p such as paper dust and the fibrous foreign substance f are dammed up at the tip of the paper dust removing member 42. However, when only the rotation in the same direction is performed, the paper dust pressed against the tip of the paper dust removing member 42 may be hardened and fixed to the tip of the paper dust removing member 42. In that case, the tip of the paper dust removing member 42 is lifted by powdered material such as paper dust sent one after another, and a gap is formed between the surface of the resist driven roller 11b and the tip of the paper dust removing member 42. The powder slips through. FIG. 3A shows such a state.

  Further, when the fibrous foreign matter f accidentally enters between the surface of the resist driven roller 11b and the tip of the paper dust removing member 42, a fibrous object is caught on the tip of the paper dust removing member 42, whereby the surface of the resist driven roller 11b. As a result, a gap is formed at the tip of the paper dust removing member 42, so that the paper dust slips through the periphery. FIG. 3B shows such a state.

  Therefore, as an embodiment of the present invention, the registration driven roller 11b is rotated counterclockwise in the drawing immediately before the image forming operation in the image forming unit 2 is finished and the machine is stopped. That is, the registration driving roller 11a is rotated so as to rotate in the direction opposite to the rotation direction for carrying a normal sheet. Then, even if there is a powdery substance p such as paper dust collected on the tip of the paper dust removing member 42 or a fibrous foreign matter f that has been caught, the paper dust removing member 42 comes off from the tip of the paper dust removing member 42. 4A and 4B show such a state. Therefore, when the next image forming operation is started, the tip of the paper dust removing member 42 is in a relatively clean state, so that the paper dust lump or fibrous matter can be easily removed from the surface of the resist driven roller 11b. Can always maintain good cleaning performance. Further, the powdery material p and the caught fibrous foreign matter f are prevented from adhering to the roller on the side not having the paper dust removing means so that the image formation in the image forming unit 2 is not affected. be able to.

  In the configuration of the illustrated embodiment, since the paper dust removing member 42 and the shield member 45 constitute a closed paper dust collecting unit, the reverse rotation amount of the registration roller pair 11 is the tip of the paper dust removing member 42. The portion that has slidably contacted with the shield member 45 does not come out of the unit beyond the tip of the shield member 45, so that the object that has been blocked by the paper dust removing member 42 does not come out of the paper dust collecting case 44.

  Further, when the paper dust removing member 42 is configured as an open type paper dust collecting unit having only a portion for storing paper dust and the like, the reverse amount of the registration roller pair 11 is in sliding contact with the tip of the paper dust removing member 42. It is preferable that the portion does not return to the nip portion of the registration roller pair 11 so that an object that has been blocked by the paper dust removing member 42 does not adhere to the registration driving roller 11a.

  In the illustrated embodiment, the paper dust removing member 42 is made of a polyester film having a thickness of about 0.1 mm to 0.3 mm as described above. It is also possible to adopt a method of capping or wiping paper dust or the like by bringing them into contact with each other.

  In the illustrated embodiment, only the removal of paper dust and the like in the registration roller pair 11 has been described. However, the present invention is not limited to this, and the present invention is not limited to this. Of course, it can be applied.

1 is a schematic sectional view of an example of an image forming apparatus to which the present invention is applied. Sectional drawing which expands and shows the principal part of one Example of invention Enlarged view showing the phenomenon occurring on the surface of the resist driven roller and the tip of the paper dust removing member Enlarged view showing the phenomenon occurring on the surface of the resist driven roller and the tip of the paper dust removing member

Explanation of symbols

1: Image forming apparatus body 2: Image forming unit 3: Photosensitive drums 4a, 4b: Paper feed cassette 4: Paper feed unit 5: Manual paper feed unit 6: Duplex unit 7: Transfer belt 8: Fixing roller pair 9: Ejection Paper roller pair 10: Conveying roller 11: Registration roller pair 11a: Registration driving roller 11b: Registration driven roller 12: Switching claw 13: Reversing claw 14: Reversing roller 15: Switchback path 16: Duplex unit conveying path 20: Lower guide plate 21: Upper guide plate 42: Paper dust removing member 43: Paper dust removing member support plate 44: Paper dust collecting case 45: Shield member p: Powdery material such as paper dust f: Fibrous foreign matter

Claims (5)

It has a removing member that removes powdery substances such as paper dust and fibrous foreign matters adhering to the conveying roller pair for conveying the sheet to the image forming unit by sliding on one conveying roller of the conveying roller pair. In the paper dust removing device of the image forming apparatus, after the image forming operation in the image forming unit is completed, the transport roller pair is rotated in a direction opposite to a rotation direction when transporting the paper to the image forming unit. An apparatus for removing paper dust and the like of the image forming apparatus. 2. The paper dust removal device of the image forming apparatus according to claim 1, wherein the contact portion of the one transport roller with the removal member is reversed from a corresponding contact position to a nip position of the transport roller pair. An apparatus for removing paper dust or the like of an image forming apparatus, which is performed within a range that does not return. The apparatus for removing paper dust or the like of the image forming apparatus according to claim 1, further comprising a storage part for storing powdery substances such as paper powder or fibrous foreign matters removed by the removing member, and at a position away from the removing member. A seal member that seals the storage portion; and the reverse rotation of the pair of transport rollers is performed in a range where the contact portion of the one transport roller with the removal member does not reach the seal portion by the seal member. An apparatus for removing paper dust and the like of an image forming apparatus. An image forming apparatus comprising: the paper dust removing device of the image forming apparatus according to claim 1 as a paper dust removing device for a pair of paper transport rollers. An image forming apparatus comprising: the paper dust removing device of the image forming apparatus according to claim 1 as a paper dust removing device for a pair of registration rollers.

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