JP5040513B2 - Recording paper transport device for image forming apparatus - Google Patents

Description

  The present invention relates to a recording paper conveyance device of an image forming apparatus such as a copying machine or a printer.

  In an image forming apparatus such as a copying machine or a printer, an image carrier such as a photosensitive member or an intermediate transfer member is disposed in an image forming unit for forming an image, and a transfer mechanism is provided at a position corresponding to the image carrier. Is provided.

  Briefly describing the image forming operation of the image forming unit, a laser beam modulated by an image signal is projected onto the surface of an image carrier whose surface is uniformly charged, thereby forming an image latent image. The formed image latent image is developed with toner loaded in the developing device, and a toner image is formed on the surface of the image carrier. The formed toner image is transferred to a recording sheet conveyed by a transfer device arranged at a transfer position, and is fixed to form an image on the recording sheet.

  In order to transfer the toner image described above to the recording paper, it is necessary to transport the recording paper to the transfer position in accordance with the timing at which the toner image on the surface of the image carrier reaches the transfer position. For this reason, a registration roller pair is arranged in addition to the conveyance roller on the upstream side of the transfer apparatus in the conveyance direction of the recording paper, and the recording paper is conveyed in advance to the nip portion of the registration roller pair by the conveyance roller and temporarily stops. Then, the registration roller pair starts to rotate at the timing when the toner image on the surface of the image carrier reaches the transfer position, and the recording paper is conveyed to the transfer position.

  When the recording paper is conveyed to the nip portion of the registration roller pair and temporarily stops, the conveyance roller continues to rotate even if a part of the leading edge of the recording paper comes into contact with the nip portion of the registration roller pair. The inclination is corrected, and the leading edge of the recording paper comes into contact with the nip portion of the registration roller pair to stop the rotation of the conveying roller.

  Therefore, when all the leading edge of the recording paper comes into contact with the nip portion of the registration roller pair, the recording paper is slackened to form a loop, and the loop is formed on the upper and lower guides arranged along the recording paper conveyance path. Makes contact and generates abnormal noise. Further, when the conveyance of the recording paper is started and the loop is eliminated, the loop comes into contact with the guide, and an abnormal noise is generated.

  Since the generation of such abnormal noise is not preferable, the following measures are taken.

  That is, regarding the impact sound generated when the loop generated on the recording paper comes into contact with the upper guide, a configuration has been proposed in which the upper guide rotates when the loop comes into contact with the upper guide, and the impact sound is relaxed by a spring ( Patent Document 1).

In addition, the impact sound generated when the loop of the recording paper is released and the loop comes into contact with the lower guide is supported by the lower guide elastically held at the lower side of the loop to prevent the generation of the impact sound. It has been proposed (Patent Documents 2 and 3).
JP-A-9-86728 JP 2005-82355 A JP 2001-348142 A

  The upper guide rotation movement system, which is configured to reduce the impact sound generated when the loop generated on the recording paper contacts the upper guide, is designed so that the loop contacts the lower guide when the recording paper loop disappears. In addition, the guide has a curved shape along the loop, and the conveyance speed of the recording paper is high before the loop is formed and comes into contact with the upper guide. There is an inconvenience that it is difficult to hold down.

  In addition, when the recording paper loop is eliminated, the elastically attached lower guide system that suppresses the impact sound generated when the loop contacts the lower guide contacts the upper guide when the loop is formed. In addition, when the trailing edge of the recording paper passes the transport roller, the lower guide held by the recording paper returns to its original position elastically, but at this time, the trailing edge of the recording paper jumps up and hits the upper guide, There is an inconvenience that an impact sound is generated.

  Furthermore, the lower guide protrudes above the recording paper leading edge moving path between the conveying roller and the registration roller, and the moving direction of the recording paper leading edge is suddenly changed twice. There is a possibility of recording paper conveyance failure.

  The present invention aims to solve the various problems described above.

The present invention solves the above-mentioned problems, and the invention according to claim 1 is formed on a sheet feeding device that feeds the stored recording paper toward the image forming device, and an image carrier of the image forming device. An image forming apparatus comprising a transfer device for transferring a toner image onto a recording paper, comprising: a recording paper transport device provided with a pair of registration rollers between a transport roller of the paper feeding device and a transfer device; The device conveys the recording paper loop that occurs upstream of the registration roller pair in the recording paper conveyance direction when the recording paper is conveyed to the registration roller pair and the leading end stops. A movable guide provided with a muffling member that moves in a direction crossing the direction, and a fixed guide that is disposed at a position opposite to the movable guide and spaced at an interval equal to or greater than the thickness of the recording paper, the movable guide and the fixed guide With The configured such that the recording paper is conveyed, the movable guide, the rolling element is fitted movably to the slit provided in a direction crossing the recording sheet conveying direction, of the slit, the movement direction of the rolling element The recording paper conveying device of the image forming apparatus is characterized in that a silencer is disposed at both ends of the image forming apparatus.

According to a second aspect of the present invention, there is provided a paper feeding device for feeding the stored recording paper toward the image forming device, and a transfer for transferring the toner image formed on the image carrier of the image forming device to the recording paper. An image forming apparatus including a recording paper transport device including a registration roller pair between a transport roller and a transfer device of the paper feeding device, wherein the recording paper transport device is a recording paper of a resist roller pair. A silencer that moves the recording paper loop that occurs upstream of the registration paper pair in the recording paper conveyance direction upstream in the recording paper conveyance direction when the recording paper is conveyed upstream of the conveyance direction to the registration roller pair and stops its leading edge. A movable guide provided with a member, and a fixed guide disposed at a position opposite to the movable guide at a distance greater than the thickness of the recording paper, and the recording paper is conveyed between the movable guide and the fixed guide. Configured to Is, the movable guide, said fixed guide direction with a spring member which presses and biases the rolling elements that is fitted into the slit provided in a direction crossing the recording sheet conveyance direction according to the thickness of the recording paper passing And the movable guide itself moves in a direction crossing the recording paper conveyance direction against the urging force of the spring member when the rolling element reaches the movement limit. It is a paper transport device.

The movable guide is disposed outside a line connecting the roller of the sheet feeding device and the nip portion of the registration roller pair.

  The fixed guide disposed at a position facing the movable guide may be a roller disposed rotatably.

  The fixed guide disposed at a position facing the movable guide may be a fixed guide that does not rotate.

  As described above, according to the present invention, the recording paper transporting device can perform recording on the registration roller pair when the recording paper is transported to the registration roller pair on the upstream side in the recording paper transport direction of the registration roller pair and the leading end is stopped. A movable guide provided with a muffling member for moving a recording paper loop generated upstream in the paper conveyance direction in a direction crossing the recording paper conveyance direction, and a position opposed to the movable guide with an interval equal to or greater than the thickness of the recording paper The recording sheet is conveyed between the movable guide and the fixed guide.

  As a result, the recording paper is transported to the pair of registration rollers and stopped, and when the recording paper loop occurs on the upstream side of the registration paper pair in the recording paper transport direction, and the recording paper loop is started and the recording paper loop is eliminated. When the recording paper collides with the movable guide or the fixed guide, an impact sound is generated. However, the recording paper and the movable guide or the fixed guide are close to each other, and the moving distance is small. Since the member is provided, the impact sound generated when the recording paper collides with the movable guide or the fixed guide is hidden behind the normal operation sound of the image forming apparatus and cannot be heard.

  Also, when the trailing edge of the recording paper passes through the conveyance roller of the paper feeding device and moves toward the movable guide, the impact sound generated by the trailing edge of the recording paper jumping up is close to the recording paper and the movable guide, The moving distance is small, and the movable guide is provided with a sound deadening member. Therefore, the impact sound generated when the recording paper collides with the movable guide is hidden behind the normal operation sound of the image forming apparatus and cannot be heard.

  FIG. 1 is a front view for explaining an outline of an example of the configuration of an image forming apparatus embodying the present invention. The image forming apparatus 10 includes a scanner device 11, an image forming device 12, a conveying device 20, and a paper feeding device 14. Consists of

  The scanner device 11 includes a document glass 11a for placing a document on an upper surface thereof, and a scanning mechanism 11b having a scanning optical system disposed on the lower side thereof. The scanner mechanism 11b scans a document image. The obtained image signal is output to the image forming device 12.

  The image forming device 12 includes a photoreceptor 12a, a charging device 12b, a laser light projection device 12c, a developing device 12d, a transfer roller 12e, a cleaning device 12f, a discharge tray 12g, and a discharge tray 12g disposed on the periphery of the photoconductor 12a. The fixing device 12h is arranged.

  The paper feeding device 14 feeds the stored recording paper P toward the image forming device 12, and a conveying device 20 according to the present invention is interposed between the paper feeding device 14 and the image forming device 12. Be placed.

  The image forming operation of the image forming apparatus will be briefly described below. First, the power of the image forming image forming apparatus 10 is turned on, the photoconductor 12a of the image forming apparatus 12 starts rotating at a predetermined rotation speed, and the developing device 12d, the charging device 12b and other devices also start preparatory operations. When an original is placed on the original glass 11a on the upper surface of the scanner device 11 and the original image is scanned by operating the scanner device 11, an image signal is output from the scanning mechanism 11c.

  The output image signal is input to the laser light projection device 12c of the image forming device 12, and the laser light modulated by the image signal is projected onto the surface of the photoreceptor 12a that is uniformly charged in advance by the charging device 12b, An image latent image is formed on the surface of the photoreceptor 12a. The formed image latent image is developed with toner loaded in the developing device 12d, and a toner image is formed on the surface of the photoreceptor 12a. The formed toner image is transferred to the recording paper P conveyed by the transfer roller 12e disposed at the transfer position, fixed by the fixing device 12h, and an image is formed on the recording paper P. Discharged. The toner remaining on the surface of the photoreceptor 12a is cleaned by the cleaning device 12f to prepare for the next image forming operation.

  In order to transfer the toner image described above to the recording paper P, it is necessary to transport the recording paper P to the transfer position in accordance with the timing at which the toner image on the surface of the photoreceptor 12a reaches the transfer roller 12e. A conveying device 20 according to the present invention described below is disposed between the paper feeding device 14 and the image forming device 12.

  2A and 2B are diagrams for explaining the configuration of the transporting device 20. FIG. 2A is a diagram for explaining various rollers and guides arranged along the transporting path, and FIG. It is an enlarged front view explaining a structure.

  Various rollers and guides arranged along the conveyance path will be described with reference to FIG. On the upstream side in the transport direction of the recording paper P transported toward the photoconductor 12a and the transfer roller 12e, the transport roller pair 21a and 21b, the fixed guide 22, the movable guide 23, and the movable guide are sequentially arranged from the sheet feeding device 14 side. 23, a fixed guide roller 24, a registration roller front fixed guide 25a and 25b, a registration roller pair 27a and 27b, a transfer guide 28a, and a transfer guide 28a. 28b is arranged along the conveyance path.

  As shown in FIG. 2B, the movable guide 23 has rollers 23c and 23c, which are rolling elements, movably disposed in slits 23b provided in the frame 23a. , 23d are attached. Furthermore, fixed guides 23g and 23g are attached to the movable guide 23 along the conveyance path of the recording paper P, and gently guides the leading edge of the recording paper P toward the nip portions of the registration roller pairs 27a and 27b.

  The frame 23a of the movable guide 23 is urged in the direction toward the roller 24 by a spring 23f.

  The operation of the transport device 20 will be described. In response to a paper feeding command output from a control device (not shown), the recording paper P is guided from the paper feeding device 14 by the rotation of the conveying roller pairs 21a and 21b and the fixed guide 22 and conveyed in the direction of the arrow a. 23 and the roller 24, and is guided and conveyed by the registration roller front fixed guides 25a and 25b, and the leading edge of the recording paper P comes into contact with the nip portion of the registration roller pair 27a and 27b.

  Even after the leading edge of the recording paper P comes into contact with the nip portion, the rotation of the conveying roller pairs 21a and 21b continues. Therefore, the recording paper P bends with the leading edge in contact with the nip portion, and a loop is formed. However, when a certain amount of loops are formed, the rotation of the transport roller pairs 21a and 21b stops. By forming a loop on the recording paper P, the leading edge of the recording paper P contacts the nip portion over the entire width, and the skew of the recording paper P is corrected.

  FIG. 3 illustrates a state in which the leading edge of the recording paper P is in contact with the nip portion, and the movable guide 23 is pushed laterally (rightward in FIG. 2) by the recording paper loop to form a space for forming a loop. It is a figure to do.

  Since the recording paper P is in contact with the movable guide 23 before the loop is formed, no impact sound is generated between the recording paper P and the movable guide 23 when the loop is formed.

  Since the initial position of the movable guide 23 is on the right side in FIG. 3 outside the line L connecting the nip portions of the conveying roller pairs 21a and 21b and the nip portions of the registration roller pairs 27a and 27b, the recording paper P has a loop. It is curved toward the movable guide 23 before being formed, and when the loop is formed, the curvature is further increased, and a stable loop is always formed.

  4 to 6 are views for explaining the position of the movable guide 23 when a loop is formed on the recording paper P. FIG. 4A shows various rollers and guides arranged along the conveyance path. 4A and 4B are enlarged front views illustrating the configuration of the movable guide 23. FIG.

4A and 4B show the case where the recording paper P is thin, FIGS. 5A and 5B show the case where the recording paper P is plain paper, and FIGS. 6A and 6B show the recording paper P. Shows the case of thick paper.

  When a loop is formed on the recording paper P, the force that presses the movable guide 23 in the lateral direction (rightward in FIG. 2) against the spring 23f depending on the thickness of the recording paper P and the rolling elements of the movable guide 23 The amount of movement of the roller 23c changes, and the amount of movement of the roller 23c increases in the order of the recording paper P being thin paper, plain paper, and thick paper. However, when the recording paper P is a thick paper, the roller 23c of the movable guide 23 comes into contact with the sound deadening member 23d, and the movement of the roller 23c stops. The impact when the roller 23c comes into contact with the sound deadening member 23d is alleviated by the spring 23f and the sound deadening member 23d, so no impact sound is generated.

  In the conventional configuration, when a loop is formed on the recording paper P, there may be a problem that the leading edge of the recording paper P comes off the nip portion. However, according to the configuration of the movable guide 23 of the present application, the loop formed on the recording paper P is pressed in the direction of reducing the loop by the movable guide 23 pressed by the spring 23f, and the leading edge of the recording paper P is registered. Since the recording paper P is pressed toward the roller pair 27a and 27b, the leading edge of the recording paper P is always in press contact with the nip portion of the registration roller pair 27a and 27b, and the leading edge of the recording paper P does not come off the nip portion. In addition, the conveyance failure of the recording paper P by the registration roller pairs 27a and 27b does not occur.

  FIG. 7 is a diagram for explaining a state when the loop formed on the recording paper P is eliminated. FIG. 7A is a diagram for explaining various rollers and guides arranged along the conveyance path. FIG. 4B is an enlarged front view illustrating the configuration of the movable guide 23.

is there. When the registration roller pairs 27a and 27b start to rotate, the recording paper P is conveyed toward the transfer position, and the formed loop is gradually eliminated.

  At this time, the recording paper P comes into contact with the roller 24 disposed at a position facing the movable guide 23, and the movable guide 23 and the roller 24 are brought into contact with each other by the contact force of the roller 24 and the biasing force of the spring 23f in FIG. Push back to the indicated initial position. Immediately before the loop is eliminated, the conveyance roller pairs 21a and 21b start rotating, and the entire recording paper P is conveyed.

  When the loop formed on the recording paper P is eliminated, the recording paper P moves from the state in contact with the movable guide 23 to the state in contact with the roller 24, but the moving distance at this time is short and the transport speed of the recording paper P is short. However, no impact sound is generated. Further, the impact when the movable guide 23 and the roller 24 are pushed back to the initial position and stopped is absorbed by the silencer 23d, and no impact sound is generated.

  FIG. 8 is a diagram illustrating the configuration of the transport apparatus in which a non-rotating fixed guide 29 is arranged in place of the rotatable roller 24 that is a fixed guide in the configuration of the transport apparatus described above with reference to FIG. If the fixed guide 29 is arranged instead of the rotatable roller 24, the sheet passing resistance of the recording paper P increases, but the configuration of the transport device can be simplified. Further, by applying a coating of a low friction material to the sheet passing surface of the fixed guide 29, the sheet passing resistance of the recording sheet P can be reduced.

  FIG. 9 is a diagram for comparing and explaining the state of occurrence of impact sound from the loop formation to the cancellation of the recording paper P in the transport apparatus described above.

  FIG. 9A shows a state before the loop of the recording paper P is formed. Since the recording paper P is in contact with or very close to the movable guide 23, the impact sound caused by the contact between the recording paper P and the movable guide 23 is a sound that cannot be heard behind the normal operation sound of the image forming apparatus. Only occurs.

  FIG. 9B shows a state where the loop formation of the recording paper P has been completed. Although the recording paper P abuts against the sound deadening member of the movable guide 23 and an impact sound is generated, it is less than half compared to the case without the sound deadening member.

  FIG. 9C shows a state before the loop of the recording paper P is eliminated. The recording paper P approaches or comes into contact with the roller 24, but the impact sound caused by the contact between the recording paper P and the roller 24 generates only a sound that cannot be heard behind the normal operation sound of the image forming apparatus.

  FIG. 9D shows a state in which the loop of the recording paper P has been eliminated. The recording paper P comes into contact with the roller 24, and the movable guide 23 and the roller 24 are pushed back to the initial position by the contact force of the roller 24 and the biasing force of the spring 23f. .

  FIG. 9E shows a state in which the trailing edge of the recording paper P has passed through the conveyance roller pairs 21a and 21b. The movable guide 23 and the rear end of the recording paper P are close to each other, and the amount of jumping up of the rear end of the recording paper P is slight. The impact sound when the rear end of the recording paper P collides with the movable guide 23 is Only the sound of a level that cannot be heard behind the normal operation sound of the image forming apparatus is generated.

  A recording paper transport device of an image forming apparatus, wherein a loop generated in the recording paper when the leading edge of the transported recording paper comes into contact with the nip portion of the registration roller pair, and the recording paper transport is started and the loop is This is a recording paper conveyance device of the image forming apparatus that can reduce the impact sound generated when the recording paper collides with the conveyance guide when solving.

1 is a front view for explaining an outline of an example of the configuration of an image forming apparatus that implements the present invention; The figure explaining the structure of a conveying apparatus. FIG. 4 is a diagram for explaining a state in which a leading end of a recording sheet comes into contact with a nip portion and a movable guide is pushed laterally by a recording sheet loop to form a space for forming a loop. The figure explaining the position of the movable guide at the time of loop formation in case recording paper is thin paper. The figure explaining the position of the movable guide at the time of loop formation when recording paper is plain paper. The figure explaining the position of the movable guide at the time of loop formation when recording paper is thick paper. The figure explaining a state when the loop formed in the recording paper is eliminated. The figure explaining the structure of the conveying apparatus which has arrange | positioned the guide instead of the roller in the conveying apparatus shown in FIG. The figure explaining comparatively the generation condition of the impact sound in a conveying apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 11 Scanner apparatus 11a Document glass 11b Scanning mechanism 12 Image forming apparatus 12a Photoconductor 12b Charging apparatus 12c Laser light projection apparatus 12d Developing apparatus 12e Transfer roller 12f Cleaning apparatus 12g Ejection tray 12h Fixing apparatus 14 Paper supply apparatus 20 Conveyance apparatus 21a, 21b Carrying roller pair 22 Fixed guide 23 Movable guide 23a Frame 23b Slit 23c Rolling element (roller)
23d Silencer member 23g Fixed guide 23f Spring 24 Fixed guide (rotary roller)
25a, 25b Registration roller front fixed guide 27a, 27b Registration roller pair 28a, 28b Transfer guide 29 Fixed guide (non-rotating fixed guide)

Claims (5)

An image forming apparatus including a paper feeding device that feeds a stored recording paper toward an image forming device, and a transfer device that transfers a toner image formed on an image carrier of the image forming device to the recording paper. And a recording paper transport device provided with a pair of registration rollers between the transport roller and the transfer device of the paper feeding device,
The recording paper transport device is configured to generate a recording paper loop generated upstream of the registration roller pair in the recording paper transport direction when the recording paper is transported to the registration roller pair and the leading end of the recording paper stops. A movable guide having a silencing member that moves the recording sheet in a direction crossing the recording paper conveyance direction, and a fixed guide that is disposed at a position opposite to the movable guide and spaced apart by a thickness greater than the thickness of the recording paper. The recording paper is configured to be conveyed between the guide and the fixed guide ,
In the movable guide, rolling elements are movably fitted in slits provided in a direction intersecting the recording paper conveyance direction, and silencers are disposed at both ends of the slits in the moving direction of the rolling elements . A recording paper transport device for an image forming apparatus. An image forming apparatus including a paper feeding device that feeds a stored recording paper toward an image forming device, and a transfer device that transfers a toner image formed on an image carrier of the image forming device to the recording paper. And a recording paper transport device provided with a pair of registration rollers between the transport roller and the transfer device of the paper feeding device,
The recording paper transport device is configured to generate a recording paper loop generated upstream of the registration roller pair in the recording paper transport direction when the recording paper is transported to the registration roller pair and the leading end of the recording paper stops. A movable guide having a silencing member that moves the recording sheet in a direction crossing the recording paper conveyance direction, and a fixed guide that is disposed at a position opposite to the movable guide and spaced apart by a thickness greater than the thickness of the recording paper. The recording paper is configured to be conveyed between the guide and the fixed guide,
The movable guide includes a spring member that presses and biases in the fixed guide direction, and a rolling element fitted in a slit provided in a direction intersecting the recording paper transport direction moves according to the thickness of the recording paper passing therethrough. When the rolling element reaches the movement limit, the movable guide itself moves in a direction crossing the recording paper conveyance direction against the urging force of the spring member. apparatus. The movable guide recording paper in the image forming apparatus according to claim 1 or claim 2, characterized in that it is arranged outside the line connecting the nip portion of the roller and the resist roller pair of the sheet feeding apparatus Conveying device. It said fixed guides arranged at a position opposite to the movable guide, the recording paper conveying apparatus of an image forming apparatus according to claim 1 or claim 2, characterized in that a rotatably arranged roller. It said fixed guides arranged at a position opposite to the movable guide, the recording paper conveying apparatus of an image forming apparatus according to claim 1 or claim 2, characterized in that a fixed guide does not rotate.

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