JP2009286568A - Paper delivering unit and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper delivering unit capable of canceling a nip of a delivering roller without using a solenoid, and to provide an image forming device. <P>SOLUTION: This paper delivering unit has a delivering roller 46 comprising a drive roller 50 and a driven roller 52 for delivering paper P, a drive motor for rotationally driving the delivering roller 46, a nip formation canceling mechanism 60, and a well-known paper width matching means. The nip formation canceling mechanism 60 has a gear 61 for a drive roller provided at an end of a shaft 51 of the drive roller 50, a gear 64 for a driven roller provided at an end of a shaft 53 of the driven roller 52, a connection gear 62 provided between the gear 61 for the drive roller and the gear 64 for the driven roller, a shaft restraining member 70 for regulating the shaft 53 of the driven roller 52, and a contacting member 72 locked between the shaft 53 of the driven roller 52 and a delivering guide plate 80 of the paper delivering unit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sheet conveying unit such as an electrophotographic copying machine and a printer, and an image forming apparatus.

  As an image forming apparatus, there is an image forming apparatus that forms a toner image on a photosensitive drum, transfers the toner image onto a sheet, fixes it, and discharges it outside the apparatus. In addition to the general image forming apparatus, as in an automatic double-sided copying machine, a sheet made as a single-sided copy is sent again to the image transfer unit in a reversed state, and the image is transferred to the back side of the sheet. There is also an image forming apparatus that discharges as a double-sided copy.

  In the case of an automatic double-sided copying machine, before and after reversing the paper, the paper is likely to be displaced in the width direction, which causes a problem that the image is displaced between the front surface and the back surface of the paper, resulting in a skew image. there were. As a countermeasure for this problem, the width of the paper is adjusted. At the time of this width adjustment, it is necessary to release the nip of the conveying roller. As a mechanism for releasing the nip, conventionally, for example, a technique using a solenoid described in Patent Document 1 has been mainly employed.

JP-A-5-323719

  However, in the conventional nip release mechanism, the heat of the single-sided copy paper after fixing is transmitted to the solenoid, and the solenoid malfunctions. Furthermore, there is a problem that the solenoid malfunctions due to the heat generated by the solenoid itself accompanying the nip release operation.

  Therefore, a main object of the present invention is to provide a paper transport unit and an image forming apparatus that can release the nip of the transport roller without using a solenoid.

  The invention according to claim 1 is a paper transport unit having a station for adjusting the width of the paper, wherein the station rotationally drives the transport roller including a drive roller and a driven roller for transporting the paper, and the transport roller. And a nip formation release mechanism that forms a nip between the drive roller and the driven roller of the transport roller when the drive motor is rotated forward and a nip of the transport roller when the drive motor is rotated reversely. A sheet width adjusting means, and the nip formation releasing mechanism is configured to rotate the drive motor in the forward rotation drive, drive stop, reverse rotation drive, drive stop, and forward drive while the paper width adjustment means The sheet transport unit is characterized in that alignment is performed.

  According to the first aspect of the present invention, there is provided a nip formation releasing mechanism that forms a nip between the driving roller and the driven roller of the conveying roller when the driving motor is rotated forward, and releases the nip of the conveying roller when the driving motor is rotated reversely. Therefore, the nip of the transport roller can be released without using a solenoid.

  The invention according to claim 2 is an invention dependent on the invention according to claim 1, wherein the nip formation release mechanism includes a drive roller gear provided at a shaft end portion of the drive roller and a shaft end portion of the driven roller. A driven roller gear, a coupling gear provided between the drive roller gear and the driven roller gear, a shaft regulating member for regulating the shaft of the driven roller, and one end at the shaft end of the driven roller. And a contact member that is slidably engaged with the housing of the paper transport unit so that the other end is slidable. When the drive motor rotates in the reverse direction, the drive force of the drive roller is connected to the drive roller gear. The paper conveying unit is configured to be transmitted to a driven roller via a gear and a driven roller gear, and the driven roller gear is a one-way gear that idles in a normal rotation direction.

  In the invention of claim 2, when the sheet is conveyed to the station for width adjustment, the drive motor stops rotating from the normal rotation and then reversely rotates. When the drive motor rotates in the reverse direction, the driven roller gear rotates in the reverse direction via the drive roller gear and the connecting gear. As a result, the driven roller moves upward along the shaft regulating member, and the nip of the transport roller is released. When the nip of the transport roller is released, the width of the paper is adjusted.

  Thereafter, the drive motor stops rotating from reverse rotation and then rotates forward. When the drive motor rotates forward, the driven roller gear is a one-way gear that idles in the forward rotation direction, and therefore the driven roller gear does not rotate. As a result, the driven roller moves downward along the shaft restricting member, and a nip of the transport roller is formed, so that the paper can be transported.

  Further, the invention according to claim 3 is an invention dependent on the invention according to claim 1 or claim 2, and is reversed with a reverse conveyance unit that reverses the sheet conveyance direction and reverses the sheet up and down. And a paper refeeding unit that feeds the paper to the transfer conveyance path.

  In the invention of claim 3, as in an automatic double-sided copying machine, a sheet created as a single-sided copy is sent again toward the image transfer unit in an inverted state, and the image is transferred to the back side of the sheet and discharged as a double-sided copy. In the case of an image forming apparatus, even if the paper is displaced in the width direction before and after the paper is reversed, the nip of the transport roller can be released without using a solenoid to adjust the width of the paper. .

  According to a fourth aspect of the present invention, there is provided an image forming apparatus comprising the paper transport unit according to any one of the first to third aspects.

  According to the fourth aspect of the present invention, since the nip of the transport roller can be released without using a solenoid that is frequently operated due to heat, an image forming apparatus with few malfunctions can be obtained.

  According to the present invention, there is a nip formation releasing mechanism that forms a nip between the driving roller and the driven roller of the conveying roller when the driving motor is rotated forward, and releases the nip of the conveying roller when the driving motor is rotated reversely. Therefore, a paper transport unit and an image forming apparatus that can release the nip of the transport roller without using a solenoid can be obtained.

  The above-described object, other objects, features, and advantages of the present invention will become more apparent from the following description of the best mode for carrying out the invention with reference to the drawings.

(Image forming device)
FIG. 1 is a schematic configuration diagram showing an image forming apparatus provided with a paper transport unit according to the present invention. The image forming apparatus includes an image forming apparatus main body 1, an image reading apparatus 20 placed on the image forming apparatus main body 1, and an automatic document feeder 22.

  The photosensitive drum 2 disposed in the image forming apparatus main body 1 is driven at a predetermined speed in a clockwise direction indicated by an arrow in the figure by a driving unit. In the vicinity of the outer periphery of the photosensitive drum 2, a charger 4, a developing device 6, a transfer belt 8, and a cleaning device 10 are provided. The surface of the photosensitive drum 2 is uniformly charged by the charger 4. A laser scanning unit 5 is disposed on the downstream side of the charger 4 in the rotation direction of the photosensitive drum 2. Laser light L emitted from the laser scanning unit 5 based on image information read by the image reading device 20 is irradiated onto the photosensitive drum 2 to form an electrostatic latent image.

  A developing device 6 is disposed on the downstream side of the laser scanning unit 5. The developing device 6 is for applying toner to the photosensitive drum 2. A transfer belt 8 is disposed on the downstream side of the developing device 6. Further, a cleaning device 10 for removing the toner remaining on the photosensitive drum 2 is disposed on the downstream side of the transfer belt 8. A transfer conveyance path 30 is arranged between the photosensitive drum 2 and the transfer belt 8. Then, the sheet P is conveyed through the transfer conveyance path 30, whereby the toner image formed on the photosensitive drum 2 is transferred to the sheet P and is carried into the fixing device 12. The paper P to which the toner image is transferred is fixed by the fixing device 12. Thus, a toner image is formed on one side of the upper side of the paper P.

  The transfer conveyance path 30 is branched into a discharge path 31 and a reverse path 32 in the branch / discharge section 14. A discharge roller 18 is disposed at the downstream end of the discharge path 31. The reversing path 32 is branched from the transfer conveyance path 30 and reversed, and the intermediate tray 16 is disposed at the downstream end thereof. The intermediate tray 16 includes a reverse conveyance path 34 and a refeed conveyance path 36. The reverse path 32 is connected to the reverse transport path 34. The reverse conveyance path 34 extends in the left-right direction (left-right direction in FIG. 1) of the image forming apparatus main body 1 with an interval below the transfer conveyance path 30.

  The reverse conveyance path 34 extends beyond the connection portion with the reversal path 32, reverses downward, and is connected to the refeed conveyance path 36. The refeed conveyance path 36 extends substantially horizontally in the left-right direction of the image forming apparatus main body 1 with an interval below the reverse conveyance path 34. The downstream end of the refeed conveyance path 36 is connected to the transfer conveyance path 30. A plurality of paper feed cassettes 11 are disposed below the refeed conveyance path 36.

  A case where double-sided printing is performed using the image forming apparatus having the above configuration will be described. The pickup roller 13 pulls out the paper P as a recording material from the paper feed cassette 11 in synchronization with the toner image and feeds it to the transfer conveyance path 30. A toner image formed on the photosensitive drum 2 is transferred onto one surface of the paper P and is carried into the fixing device 12. The paper P to which the toner image is transferred is fixed by the fixing device 12. In this way, the toner image is formed on one side of the upper side of the paper P by the paper P being conveyed through the transfer conveyance path 30.

  The sheet P conveyed through the transfer conveyance path 30 passes through the reverse path 32 and is carried upside down on the reverse conveyance path 34. The sheet carried into the reverse conveyance path 34 is conveyed in the reverse direction, and is reversed again and carried into the refeed conveyance path 36. The paper P carried into the re-feed conveyance path 36 is re-fitted into the transfer conveyance path 30 with the image surface facing upside down again. While the sheet re-loaded into the transfer conveyance path 30 is conveyed again through the transfer conveyance path 30, the toner image formed on the photosensitive drum 2 by being inverted upside down is transferred to the other side of the sheet P, and the fixing device 12 is carried in. The paper P on which the toner images are formed on both sides passes through the discharge path 31 and is discharged out of the apparatus as a printed matter by the discharge roller 18 and is stacked on a discharge tray (not shown).

(Paper transport unit)
Next, the paper transport unit will be described. The paper transport unit includes a transfer transport path 30, a discharge path 31, a reverse path 32, a reverse transport path 34, and a refeed transport path 36. The transfer conveyance path 30 is provided with a registration portion in which a registration roller 42 is disposed immediately before the photosensitive drum 2, and a station S for adjusting the width of the sheet is provided on the upstream side of the registration portion. In the registration unit, the paper P is sent out toward the image transfer unit in accordance with the timing at which the toner image is formed on the photosensitive drum 2.

  A detailed configuration of the transport roller 46 of the station S is shown in FIGS. 2 is an external perspective view of the transport roller 46 as viewed from one roller shaft end side, FIG. 3 is an external perspective view of the other roller shaft end side, and FIG. 4 is a side view.

  The station S includes a transport roller 46 including a drive roller 50 and a driven roller 52 for transporting the paper P, a drive motor (not shown) for rotationally driving the transport roller 46, a nip formation release mechanism 60, Well-known sheet width adjusting means (not shown). The nip formation release mechanism 60 includes a driving roller gear 61 provided at the end of the shaft 51 of the driving roller 50, a driven roller gear 64 provided at the end of the shaft 53 of the driven roller 52, and a driving roller. A connecting gear 62 provided between the gear 61 and the driven roller gear 64, a shaft regulating member 70 for regulating the shaft 53 of the driven roller 52, a shaft 53 of the driven roller 52, and a conveyance guide plate 80 of the paper conveyance unit. And a contact member 72 locked between the two.

  The driven roller 52 is pressed against the driving roller 50 by a pressure spring 70. Both ends of the crimp spring 70 are locked to the shaft restricting member 70. The shaft restricting member 70 sandwiches both ends of the shaft 53 of the driven roller 52 in pairs, and the shaft 53 is movable between the shaft restricting members 70 in the vertical direction. The contact member 72 is screwed to the shaft 53 outside the shaft restricting member 70, and the front end portion of the contact member 72 is slidably locked on the conveyance guide plate 80. The connecting gear 62 is rotatably attached to the arm member 66 and is pressed against the driving roller gear 61 and the driven roller gear 64 by a spring force with the hole 68 as a fulcrum. The driven roller gear 64 is a one-way gear that idles in the forward rotation direction.

  When the drive motor is rotated forward, a nip between the drive roller 50 and the driven roller 52 is formed. On the other hand, when the driving motor rotates in the reverse direction, the driving force of the driving roller 50 is transmitted to the driven roller 52 via the driving roller gear 61, the connecting gear 62, and the driven roller gear 64, and the nip between the driving roller 50 and the driven roller 52 is reached. Is released. Then, while the nip formation releasing mechanism 60 drives the drive motor to rotate forward, stop driving, reversely rotate, stop driving, and drive forward, the paper width adjusting unit adjusts the width of the paper P.

  Next, the effect of the station S will be described. The station S is normally in a state in which a nip between the driving roller 50 and the driven roller 52 is formed and the sheet can be conveyed (refer to FIGS. That is, the drive roller 50 is rotated forward in the clockwise direction by the drive motor. Since the driven roller 52 is pressed against the driving roller 50 by the spring force of the pressure spring 70, the driven roller 52 is rotated in the counterclockwise direction following the rotation of the driving roller 50.

  At this time, the driving force in the clockwise direction (forward rotation direction) of the drive motor is transmitted to the driven roller gear 64 via the drive roller gear 61 and the connecting gear 62. Although the driving force in the clockwise direction (forward rotation direction) is transmitted to the driven roller gear 64, the driven roller gear 64 is a one-way gear that idles in the forward rotation direction, and therefore does not rotate.

  When the paper P is conveyed to the station S, the drive motor stops rotating from the normal rotation and then reversely rotates (see FIGS. 5 to 7). When the drive motor rotates counterclockwise, the driving force of the drive motor in the counterclockwise direction (reverse rotation direction) is transmitted to the driven roller gear 64 via the drive roller gear 61 and the connecting gear 62. . The driving force in the counterclockwise direction (reverse rotation direction) is transmitted to the driven roller gear 64, and the driven roller gear 64 rotates in the counterclockwise direction (reverse rotation direction).

  However, since the contact member 72 connects the shaft 53 of the driven roller 52 and the conveyance guide plate 80, the front end portion of the contact member 72 slides on the conveyance guide plate 80, and the contact member 72 is lifted. As a result, the rotational driving force transmitted to the driven roller gear 64 changes to a linear driving force that moves the driven roller 52 upward along the shaft restricting member 70 against the spring force of the pressure-bonding spring 70. 46 (the driving roller 50 and the driven roller 52) is released.

  When the nip of the conveying roller 46 is released, the width of the paper P is adjusted by the paper width adjusting means. The paper width adjusting means is well known, and a detailed description of its configuration is omitted. When the width adjustment operation for the paper P is completed, the drive motor stops rotating from the reverse rotation and then rotates forward. When the drive motor rotates in the forward direction, a driving force in the clockwise direction (forward rotation direction) is transmitted to the driven roller gear 64. However, the driven roller gear 64 is a one-way gear that idles in the forward rotation direction. do not do. This eliminates the linear driving force that raises the driven roller 52 upward along the shaft restricting member 70 against the spring force of the pressure spring 70, so that the tip of the contact member 72 is moved by the spring force of the pressure spring 70. Slides on the conveyance guide plate 80 to the original position, and the contact member 72 descends. Accordingly, the driven roller 52 moves downward along the shaft restricting member 70 to form a nip of the conveying roller 46, and the sheet P can be conveyed.

  In the station S configured as described above, when the drive motor is rotated forward, a nip of the transport roller 46 (drive roller 50 and driven roller 52) is formed, and when the drive motor is rotated reversely, the nip of the transport roller 46 is released. Since the nip formation release mechanism 60 is provided, the nip of the transport roller 46 can be released and the width of the paper P can be adjusted without using a solenoid.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is carried out within the range of the summary.

1 is a schematic configuration diagram illustrating an image forming apparatus according to the present invention. It is the external appearance perspective view which looked at the conveyance roller from the one roller shaft end side. FIG. 3 is an external perspective view of the transport roller shown in FIG. 2 as viewed from the other roller shaft end side. It is a side view of the conveyance roller shown in FIG. It is the external appearance perspective view which looked at the conveyance roller which canceled the nip from the one roller shaft end side. FIG. 6 is an external perspective view of the transport roller shown in FIG. 5 as viewed from the other roller shaft end side. FIG. 6 is a side view of the conveyance roller illustrated in FIG. 5.

Explanation of symbols

30 Transfer conveyance path 34 Reverse conveyance path 36 Refeed conveyance path 46 Conveyance roller 50 Drive roller 52 Driven roller 60 Nip formation release mechanism 61 Drive roller gear 62 Connection gear 64 Driven roller gear 70 Shaft regulating member 72 Contact member 80 Conveyance Guide plate S station

Claims (4)

Image forming apparatus is a paper transport unit having a station for adjusting the width of paper,
A transport roller composed of a drive roller and a driven roller for transporting paper, a drive motor for rotationally driving the transport roller, and a drive roller and a driven roller for the transport roller when the station rotates forward. A nip forming release mechanism that forms a nip of a roller and releases the nip of the transport roller when the drive motor is rotated in reverse, and a paper width adjusting means,
The nip formation release mechanism performs sheet width alignment by the sheet width adjusting means while the drive motor is driven to rotate forward, stop driving, reversely rotate, stop driving, and rotate forward;
A paper transport unit.   The nip formation release mechanism includes a driving roller gear provided at a shaft end portion of the driving roller, a driven roller gear provided at a shaft end portion of the driven roller, the driving roller gear, and the driven roller. A coupling gear provided between the gears, a shaft regulating member that regulates the shaft of the driven roller, one end locked to the shaft end of the driven roller, and the other end to the housing of the paper transport unit When the drive motor rotates in the reverse direction, the driving force of the drive roller is transmitted to the driven roller via the drive roller gear, the connecting gear, and the driven roller gear. The paper transport unit according to claim 1, wherein the driven roller gear is a one-way gear that idles in a forward rotation direction.   2. The reversing conveyance unit that reverses the conveyance direction of the sheet and reverses the sheet up and down, and the refeed conveyance unit that sends the reversed sheet to the transfer conveyance path. Item 3. A paper transport unit according to Item 2.   An image forming apparatus comprising the paper transport unit according to claim 1.

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