JP2008127181A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device of structure that a paper sheet straddling a conveying unit and a device body can be drawn out of the device body together with the conveying unit without breaking the conveying unit when drawing it out of the device body. <P>SOLUTION: With operation for drawing a paper feeding cassette 6 out of the device body 10, a pair of conveying rollers 41a and 41b are rotated in a direction for housing the paper sheets in the conveying unit 4. In order to rotate the pair of conveying rollers 41a and 41b, flat teeth 62 are formed in the moving direction in a side surface of the paper feeding cassette 6, and gears 81-83 engaged with the flat teeth 62 so as to transmit drive to the pair of conveying rollers 41a and 41b and pulleys P<SB>1</SB>-P<SB>4</SB>, and belts B<SB>1</SB>-B<SB>2</SB>are arranged in the device body 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a printer, a facsimile machine, and a copying machine, and more particularly to an image forming apparatus in which a paper feed cassette is inserted and removed in a direction orthogonal to a paper transport direction.

  A so-called front loading method for entering and exiting the sheet feeding cassette in and out of the image forming apparatus main body in a direction orthogonal to the sheet feeding direction is widely adopted from the viewpoint of ease of work. Furthermore, recently, in order to reduce the size of the apparatus, a product in which a transport unit for transporting paper fed from a manual feed tray is disposed directly above the paper feed cassette has been commercialized. FIG. 4 is a schematic diagram of a paper feeding unit in the image forming apparatus having such a structure.

The feeding of the image forming apparatus of FIG. Is performed from the paper feed cassette 6 'and the manual feed tray T _2. The paper feed cassette 6 ′ is provided in the apparatus main body 10 so as to be able to enter and exit in a direction orthogonal to the paper feed direction, and paper of a predetermined size is stored in the paper feed cassette 6 ′. On the other hand, the manual feed tray T ₂ is provided on the side surface of the apparatus main body 10 so as to be rotatable about a shaft 50 between a storage position and a use position, and the user can perform image formation on a desired sheet. Rotate to use position and place desired paper on it.

The paper stored in the paper feed cassette 6 ′ is pulled out in the direction of the transport path by the pickup roller 21, sent one by one to the transport path by the paper feed roller 22 and the separating roller 23, and transported to the registration roller pair 24. On the other hand, the sheets placed on the manual feed tray T ₂ are sent out one by one to the conveying path by the paper 51 and the separating roller 54 that are hung on the rollers 51 and 52. The sheet fed from the manual feed tray T ₂ is conveyed to the registration roller pair 24 through a conveyance unit 4 provided with a plurality of conveyance roller pairs 41, 42, 43 provided immediately above the sheet feeding cassette 6 ′. Is done.

  As described above, the paper feed cassette 6 'is put in and out in a direction perpendicular to the paper feed direction. Similarly, the transport unit 4 is put in and out in a direction perpendicular to the paper feeding direction, but can be pulled out after the paper feeding cassette 6 ′ is pulled out from the apparatus main body 10.

  In such a paper feeding mechanism, when a paper jam occurs in the paper feeding / conveying path, the user pulls out the paper feeding cassette 6 'and the conveying unit 4 from the apparatus main body 10 as a countermeasure, and removes the jammed paper. There is a need to.

  FIG. 5 shows an enlarged view of a portion surrounded by a circle in FIG. As shown in this figure, when the paper P is held between the paper feeding belt 53 and the separating roller 54 and the transport unit 4 is pulled out from the apparatus main body 10, the paper P is torn and a part of the paper P enters the apparatus main body. There was some remaining. Pulling out the sheet pieces remaining in the apparatus main body is a heavy burden on the user, and at the same time, there is a risk that the sheet feeding belt 53 and the separating roller 54 may be damaged by applying an unexpected force.

As a technique for solving the same problem in the paper feed cassette, for example, in Patent Document 1, a protruding piece extending on the paper is provided in the side guide on the back side in the direction of entering and exiting the paper feed cassette, and the paper feed cassette is pulled out from the apparatus main body. At the same time, a technique has been proposed in which the jammed paper is carried out of the apparatus main body together with the paper feed cassette. Japanese Patent Application Laid-Open No. 2004-228688 proposes a technique that releases the pressure contact between the transport roller and the transport roller in conjunction with the operation of pulling out the paper feed cassette so that the jammed paper can be easily removed.
Japanese Patent Laid-Open No. 10-1229849 JP 2000-219357 A

  However, in the former proposed technique, the jammed paper is forcibly pulled out by the protruding piece formed on the side guide, so that the paper may still be damaged. Even in the latter proposed technique, even if the pressure contact between the transport roller and the transport roller is released, there is a possibility that the paper does not return to the paper feed cassette and remains in the apparatus main body. In addition, these proposed technologies are originally intended for paper feed cassettes and cannot be directly applied to a transport unit.

  The present invention has been made in view of such a conventional problem, and an object of the present invention is to break a sheet sandwiched between a sheet feeding belt and a separating roller when the transport unit is pulled out from the apparatus main body. Without being able to be pulled out of the apparatus main body together with the transport unit.

  According to the present invention, a paper feed cassette that is put in and out in a direction orthogonal to the paper transport direction and the paper feed cassette are disposed immediately above the paper feed cassette, and can be pulled out after the paper feed cassette is drawn out from the apparatus main body. An image forming apparatus including a transport unit including at least one pair of transport rollers, wherein the sheet is accommodated in the transport unit in conjunction with the paper cassette being pulled out from the apparatus main body. In addition, an image forming apparatus including a sheet feeding unit that rotates the pair of conveying rollers is provided. In the present specification, the rotation direction of the pair of conveying rollers refers to the rotation direction in the nip portion.

  From the viewpoint of reliably and efficiently rotating the conveying roller pair in conjunction with the paper cassette being pulled out from the apparatus main body, as the paper feeding means, flat teeth formed in the direction of entering and exiting the outer peripheral surface of the paper cassette A gear provided in the apparatus main body and having gears that engage with the spur teeth and transmit driving force to the pair of conveying rollers may be used.

  When the transport unit is provided with at least two transport roller pairs, when the transport unit is pulled out from the apparatus main body, the paper feed cassette is removed from the apparatus main body in order to pull out the paper together with the transport unit without damaging the paper. In conjunction with the drawing, it is preferable that the conveyance roller pair on the upstream side in the paper conveyance direction is rotated in the same direction as the paper conveyance direction, and the conveyance roller pair on the downstream side in the paper conveyance direction is rotated in the direction opposite to the paper conveyance direction. .

  The image forming apparatus according to the present invention is provided with a paper feed cassette that is put in and out in a direction orthogonal to the paper transport direction, and is disposed immediately above the paper feed cassette, and can be pulled out after the paper feed cassette is drawn out from the apparatus main body. And a transport unit including at least one transport roller pair, and the transport roller pair in the direction in which the paper is stored in the transport unit in conjunction with the paper cassette being pulled out from the apparatus main body. Since the paper feeding means for rotating is provided, when the transport unit is pulled out from the apparatus main body, the paper sandwiched between the paper feed belt and the separating roller can be pulled out of the apparatus main body together with the transport unit without breaking.

  As the paper feeding means, a flat tooth formed in the direction of entering and exiting the outer peripheral surface of the paper feed cassette, and a gear disposed on the apparatus main body and engaged with the flat tooth to transmit driving to the pair of conveying rollers. When the provided one is used, the conveyance roller pair can be reliably and efficiently rotated in conjunction with the paper feed cassette being pulled out from the apparatus main body.

  When the transport unit includes at least two transport roller pairs, the transport roller pair on the upstream side in the paper transport direction is rotated in the same direction as the paper transport direction in conjunction with the paper cassette being pulled out from the apparatus main body. When the conveyance roller pair on the downstream side in the paper conveyance direction is rotated in the direction opposite to the paper conveyance direction, the conveyance unit is not broken between the conveyance unit and the apparatus main body when the conveyance unit is pulled out from the apparatus main body. At the same time, it can be pulled out of the main body.

  FIG. 1 is a schematic diagram showing an embodiment of an image forming apparatus according to the present invention. The image forming apparatus in FIG. 1 is a color image forming apparatus, and the image forming unit includes image forming units 11 to 14 for each color of magenta (M), cyan (C), yellow (Y), and black (K). In addition, a color image or a monochrome image is formed by these image forming units 11 to 14. Around the photosensitive drums 11a to 14a made of, for example, amorphous silicon, which can be rotated in the direction of the arrow shown in the figure, a charging unit 31, an exposure unit 32, a developing unit 33, a cleaning unit 34, and the like rotate the drum. They are arranged in order from the upstream side.

  The magenta (M) image forming unit 11 will be described as an example. The surface of the photosensitive drum 11 a is uniformly charged positively or negatively by the charging unit 31. On the other hand, image data read by a reading device (not shown) is written on the surface of the photosensitive drum 11a by a laser scanner (exposure unit) 32, and an electrostatic latent image is formed on the surface of the photosensitive drum 11a. Next, the electrostatic latent image on the photosensitive drum 11a is visualized with toner by the developing unit 33, and a toner image (magenta toner image) is formed. After the primary transfer of the toner image to the intermediate transfer belt 15 described later is completed, the toner remaining on the surface of the photosensitive drum 11a is cleaned and removed by the cleaning unit 34. Similarly, in the other image forming units 12 to 14, a cyan toner image, a yellow toner image, and a black toner image are formed.

  Above the image forming units 11 to 14, intermediate transfer rollers 19 a to 19 d and an intermediate transfer belt 15 are disposed. The intermediate transfer belt 15 includes a predetermined belt body that is stretched around a driving roller 16, a driven roller 17, and a tension roller 18. The intermediate transfer belt 15 is opposed to the photosensitive drums 11a to 14a by the intermediate transfer rollers 19a to 19d. While being pressed by the drums 11 a to 14 a, the drive roller 16, the driven roller 17, and the tension roller 18 are configured to rotate.

  The intermediate transfer belt 15 is rotationally driven in the direction indicated by the arrow F in the figure by the rotational driving of the driving roller 16, and the charge opposite to the toner charging polarity is applied to the intermediate transfer rollers 19 a to 19 d, thereby the photosensitive drum. The toner images formed on the surfaces 11a to 14a sequentially move to the intermediate transfer belt 15, and a color toner image is formed on the intermediate transfer belt 15.

  On the other hand, the paper P stored in the paper feed cassette 6 is pulled out by the pickup roller 21, sandwiched between the paper feed roller 22 and the separating roller 23, and transported to the transport path. Then, the paper P is conveyed to the registration roller pair 24. The registration roller pair 24 matches the timing when the color toner image on the intermediate transfer belt 15 reaches the nip portion (transfer portion) between the intermediate transfer belt 15 and the secondary transfer roller 20 stretched around the driving roller 16. Then, the paper P is sent out to the transfer portion. In the transfer portion, the sheet P is sandwiched between the intermediate transfer belt 15 and the secondary transfer roller 20, and a charge having a polarity opposite to the toner charging polarity is applied to the secondary transfer roller 20, thereby The color toner image on the transfer belt 15 moves onto the paper P.

The paper P on which the color toner image is placed is conveyed to the fixing roller pair 25. Here, the toner image is heated and pressurized by the fixing roller pair 25 and fixed on the paper P. Then, the paper P is discharged onto the paper discharge tray T ₁ by the discharge roller pair 26.

A manual feed tray T ₂ is provided on the side surface of the apparatus main body 10 so as to be rotatable about a shaft 50 between a storage position and a use position. The paper P placed on the manual feed tray T ₂ is sent out to the transport path one by one by the roller 51, the paper feed belt 53 stretched around the roller 52, and the separating roller 54. The sheet fed from the manual feed tray T ₂ is conveyed to the registration roller pair 24 through the conveyance unit 4 provided with the three conveyance roller pairs 41, 42, 43 provided immediately above the paper feed cassette 6. The After that, it passes the same route as the above-mentioned transport route. The conveyance roller pairs 41, 42, and 43 are generic names of two conveyance roller pairs (for example, conveyance roller pairs 41a and 41b) that are mounted coaxially apart from each other.

  The paper feed cassette 6 is put in and out in a direction (perpendicular to the paper surface) perpendicular to the paper transport direction. The transport unit 4 is also moved in and out in the same direction, but the transport unit 4 has a structure that cannot be pulled out unless the paper feed cassette 6 is pulled out from the apparatus main body 10.

  FIG. 2 shows a perspective view of the transport unit 4. The transport unit 4 is formed by attaching an upper lid 45 to a unit main body 44 so as to be rotatable about one side thereof. A gap between the unit main body 44 and the upper lid 45 becomes a sheet conveyance path. A conveying roller pair 41a and a conveying roller pair 41b, a conveying roller pair 42a (conveying roller 42b is not shown), and a conveying roller pair 43a (conveying roller 43b is not shown) so as to face the sheet conveying path are the unit main body 44 and Each is attached to the upper lid 45. The paper jammed in the transport unit 4 is pulled out from the apparatus main body 10 (shown in FIG. 1) by the handle 46 and the upper cover 45 is opened to take out the paper.

FIG. 3 is a perspective view showing an example of the sheet feeding means S used in the present invention. Flat teeth 62 are formed in the loading / unloading direction on the side surface of the sheet feeding cassette body 61 parallel to the loading / unloading direction. A gear 81 fixed to a rotation shaft 71 supported on the apparatus body 10 side is attached so as to mesh with the spur teeth 62. A pulley P ₁ is attached to the rotation shaft 71, and a belt B ₁ is suspended between a pulley P ₂ attached to a rotation shaft 72 rotatably supported on the apparatus body 10 side. A bevel gear 82 is attached to the end of the rotation shaft 72 and meshes with a bevel gear 83 attached to the end of the rotation shaft 73 disposed in a direction perpendicular to the rotation shaft 72. Yes.

A pulley P ₃ is fixed to the rotation shaft 73. The rotary drive to the belt B ₂ is hung drive shaft 74 between the pulley P ₃ and the pulley P ₄ which is fixed to the drive shaft 74 is transmitted. One drive roller of a pair of transport rollers 41 a and 41 b attached to the transport unit 4 is attached to the drive shaft 74. The transport rollers 41a, the 41b to be in and out together with the conveying unit 4 from the apparatus main body 10, the drive shaft 74 is capable junction isolation at between the conveying roller 41b and the pulley P _4.

According to the sheet feeding means S having such a configuration, when the paper feed cassette 6 is pulled out from the apparatus main body 10, the gear 81 is rotated by the spur teeth 62 formed on the side surface of the cassette main body 61 of the paper feed cassette 6. The rotation shaft 71 rotates. The rotary drive is transmitted to the rotating shaft 72 by a belt B ₁ that is hung on the pulley P ₁ and the pulley P _2, and further transmitted to the rotation shaft 73 by the bevel gear 82 and bevel gear 83. Then, the rotational drive is transmitted to the drive shaft 74 by the pulley P ₃ and the belt B ₂ hung on the pulley P ₄ , and the conveyance roller pair 41a, 41b accommodates the paper in the conveyance unit 4 (clockwise in this figure). ).

  Even when the paper jam occurs in the apparatus main body as shown in FIG. 5 and the paper P is sandwiched between the paper feeding belt 53 and the separating roller 54, the paper feeding cassette 6 is pulled out from the apparatus main body 10. Then, the pair of conveying rollers 41a and 41b is rotated by the sheet feeding means S described above, and the entire sheet P is stored in the conveying unit 4. As a result, when the transport unit 4 is pulled out from the apparatus main body 10, the paper P does not straddle the transport unit 4 and the apparatus main body 10, and the paper P is prevented from being broken and partially remaining in the apparatus main body. Is done.

  In the paper feeding means S of FIG. 3, only the transport roller pair 41 a and 41 b are rotated, but the other transport roller pairs 42 and 43 provided in the transport unit 4 may be rotated simultaneously. In this case, conventionally known drive transmission means such as the gears, pulleys, and belts exemplified above may be used as the driving force.

  In the embodiment described above, the breakage of the paper P at the paper carry-in portion of the transport unit 4 is a problem. However, the paper P is broken when the transport unit 4 is pulled out even at the paper discharge portion of the transport unit 4. Can occur. Therefore, it is preferable that the transport roller pair 43 on the downstream side in the paper transport direction of the transport unit 4 is rotated in the direction opposite to the paper transport direction so that the paper is stored in the transport unit 4. In this case, the rotation drive of the conveyance roller pair 43 may be the same transmission path as the rotation drive of the conveyance roller pair 41, or flat teeth 62 are formed on both side surfaces of the cassette body 61 of the paper feed cassette 6. The sheet feeding means S described above may be provided on the left and right sides, and the transmission path for rotational driving of the transport roller 41 and the transport roller 43 may be different.

1 is a schematic diagram illustrating an example of an image forming apparatus according to the present invention. It is a perspective view which shows an example of a conveyance unit. It is a schematic perspective view which shows an example of the paper feeding means used by this invention. It is a schematic diagram illustrating a paper feed mechanism in a conventional image forming apparatus. It is a figure explaining the malfunction in the conventional paper feed mechanism.

Explanation of symbols

4 transport unit 6 paper feed cassette S paper feed means 10 apparatus main body 41, 41a, 41b transport roller pair 42, 42a, 42b transport roller pair 43, 43a, 43b transport roller pair 44 unit main body 45 upper lid 62 spur tooth 81 gear

Claims (3)

A paper feed cassette that is put in and out in a direction orthogonal to the paper feed direction, and at least one transport roller that is disposed immediately above the paper feed cassette and can be pulled out after the paper feed cassette is pulled out from the apparatus main body. An image forming apparatus including a transport unit including a pair,
An image forming apparatus comprising: a sheet feeding unit configured to rotate the pair of conveying rollers in a direction in which the sheet is stored in the conveying unit in conjunction with the drawing of the sheet feeding cassette from the apparatus main body.   The paper feeding means includes a flat tooth formed in the direction of entering and exiting the outer peripheral surface of the paper feed cassette, and a gear disposed in the apparatus main body and engaged with the flat tooth to transmit driving to the pair of conveying rollers. The image forming apparatus according to claim 1, which is provided.   The transport unit includes at least two transport roller pairs, and the transport roller pair on the upstream side in the paper transport direction rotates in the same direction as the paper transport direction in conjunction with the paper cassette being pulled out from the apparatus main body. The image forming apparatus according to claim 1, wherein the pair of conveying rollers on the downstream side in the sheet conveying direction rotates in a direction opposite to the sheet conveying direction.

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