JP2007316187A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of surely performing a jamming processing with a simple constitution. <P>SOLUTION: Regarding the image forming apparatus where the jamming processing is performed by opening a lower paper guide 36 in a paper conveyance path having an upper paper guide (fixed paper guide) 35 and the lower paper guide (movable paper guide) 36, a catch stay (paper catch part) 38 for holding the jammed paper P and pulling out the paper P is provided on the lower paper guide 36. Besides, a hook is provided on the upper paper guide 35, and by locking the catch stay 38 on the hook, the lower paper guide 36 is fixed in the conveying position. Further, a handle to open the lower paper guide 36 is formed on the catch stay 38. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus in which a paper guide on one side of a paper conveyance path is opened to perform jam processing.

  Some image forming apparatuses such as copying machines, printers, and facsimile machines are configured to open a paper guide on one side to remove a jammed paper when a jam occurs in a paper transport path. For example, if a paper transport path is provided at the top of the paper feed cassette and a jam occurs in that paper transport path, the paper feed cassette is pulled out and the paper guide on one side of the paper transport path is pulled down to open it. The jammed paper is taken out.

On the other hand, in Patent Document 1, when a jam occurs in the paper conveyance path, the rotation of the conveyance roller pair is controlled to bend the paper in a loop between the two conveyance roller pairs, thereby removing the paper. The proposal is made.
JP-A-7-053088

  However, in the case of an image forming apparatus that employs a method in which a paper guide on one side is opened and the paper is removed when a jam occurs in the paper transport path, if the jammed paper is stuck in the state between the transport rollers, There is a problem that the paper is in a tension state and there is no deflection, so that it is difficult for the paper to be put on the paper and the paper cannot be pulled out easily. This problem is particularly remarkable in the case of wide paper or thick paper.

  Further, the method proposed in Patent Document 1 has a problem in that the rotation control of the conveying roller pair is complicated when a jam occurs, and the cost of the apparatus cannot be avoided.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of reliably performing jam processing with a simple configuration.

  In order to achieve the above object, an invention according to claim 1 is directed to an image forming apparatus in which the movable side paper guide of a paper conveyance path having a fixed side paper guide and a movable side paper guide is opened for jamming. The movable-side sheet guide is provided with a sheet hooking portion for sandwiching and pulling out the formed sheet.

  According to a second aspect of the present invention, in the first aspect of the present invention, the paper hooking portion is configured by a gate-type hook stay standing upright across the entire width of the movable paper guide on the paper transport surface side. Features.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a hook is provided on the fixed-side paper guide, and the movable-side paper guide is moved to the transport position by engaging the paper hooking portion with the hook. It is fixed.

  According to a fourth aspect of the invention, in the invention according to any one of the first to third aspects, a handle for opening the movable side paper guide is formed in the paper hooking portion.

  According to the first aspect of the present invention, when the movable paper guide is opened when a jam occurs in the paper conveyance path, the paper hooking portion provided on the movable paper guide pulls out the paper while sandwiching the paper. The jammed paper can be easily removed, and jamming can be reliably performed with a simple configuration in which the paper hooking portion is provided on the movable paper guide.

  According to the second aspect of the present invention, when the movable paper guide is opened when a jam occurs in the paper conveyance path, the gate-type of the movable paper guide is erected over the entire width on the paper conveyance surface side. It is possible to reliably pull out the paper with the hook stay.

  According to the invention described in claim 3, when the movable paper guide is opened and jammed, and then the movable paper guide is closed, the paper hooking portion provided on the movable paper guide is provided on the fixed paper guide. Since the movable paper guide is locked at the hook and is fixed at the transport position, the image forming apparatus can be quickly returned to a state in which an image forming operation can be performed after the jam processing.

  According to the fourth aspect of the present invention, the user can open the movable side paper guide with good workability by gripping the handle formed on the paper hooking portion during the jam processing.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a perspective view of a laser beam printer as an embodiment of an image forming apparatus according to the present invention, and FIG. 2 is a side sectional view of the laser beam printer.

  First, the basic configuration of the laser beam printer 1 will be described with reference to FIGS. 1 and 2. The laser beam printer 1 includes a box-shaped apparatus main body 1a. As shown in FIG. An inclined concave paper discharge tray 32 is provided at the center of the upper surface of the paper, and an operation display section 34 is disposed beside it. In addition, an openable and closable manual feed tray 8 (shown in an open state is shown in FIG. 2) is provided at the upper part of the front surface of the apparatus main body 1a (the front side in FIG. 1 is the front), and at the lower part of the apparatus main body 1a. A rectangular box-shaped paper feed cassette 7 that can be pulled out to the front side is provided.

  Next, the internal structure of the laser beam printer 1 will be described with reference to FIG.

  The laser beam printer 1 forms an image on a sheet based on image data transmitted from a terminal (not shown) while conveying the sheet along a sheet conveying path L provided in the apparatus main body 1a. The sheet conveying path L extends in the apparatus main body 1a from the front to the rear (from right to left in FIG. 2) substantially horizontally, and the vertical rising from the end of the horizontal part L1 approximately vertically. It is comprised by the part L2 by the side view substantially L shape.

  Further, the laser beam printer 1 includes a paper feeding unit 2 provided at a lower portion of the apparatus main body 1a, an image forming unit 3 provided at a substantially central portion in the apparatus main body 1a above the paper feeding unit 2, The fixing unit 4 disposed behind the image forming unit 3, the concave paper discharge unit 5 provided on the upper surface of the apparatus main body 1 a above the fixing unit 4, the horizontal unit L 1 of the sheet conveyance path L, and the A switchback unit 6 provided between the paper feed cassette 7 is provided.

  The paper feed unit 2 stores paper and feeds the paper toward the image forming unit 3 and includes the paper feed cassette 7 and the manual feed tray 8.

  Here, the paper feed cassette 7 has a rectangular box shape with an open upper surface, and fulfills a function of feeding sheets (not shown) stacked and accommodated therein, one by one, as shown in FIG. As shown, in the state where it is mounted in the apparatus main body 1a, it is located below the horizontal portion L1 of the paper transport path L as shown.

  The paper feed cassette 7 includes a lift plate 9 that contacts and separates from the inner bottom surface, a bottom plate 10 that moves up and down in conjunction with the contact and separation operation of the lift plate 9, and a front end of the lift plate 9 (paper feeding direction). A lift drive shaft 11 that is attached in the vicinity of the downstream end) and rotates the lift plate 9 in the direction of the arrow in FIG. 2 and a shaft that can rotate in the vicinity of the rear end (upstream end in the sheet feeding direction) of the bottom plate 10. A supporting shaft 12 is provided.

  Further, the paper feed unit 2 includes a pickup roller 13 that takes out the paper in the paper feed cassette 7 one by one, a feed roller 14 that sends out the taken paper to the horizontal portion L1 of the paper transport path L, a retard roller 15, In addition to the plurality of paper feed rollers 16, 17, 18 and the registration rollers 19 that supply the image forming unit 3 to the image forming unit 3 at a predetermined timing after temporarily waiting the fed paper, the paper placed on the manual feed tray 8 is taken out. A pickup roller 20 is provided.

  The image forming unit 3 forms an image on a sheet supplied from the sheet feeding unit 2, and is an image carrier that is rotatably disposed at a substantially central portion in the front-rear direction of the horizontal portion L 1 of the sheet conveyance path L. A photosensitive drum 21, a primary charger 22, a developing device 23, a transfer roller 24, and a cleaning device 25 disposed around the photosensitive drum 21, a laser scanner unit (LSU) 26, a toner hopper 27, and the like disposed above them. It has.

  The fixing unit 4 is for fixing the toner image transferred onto the paper in the image forming unit 3 to the paper, and includes a heating roller 28 and a pressure roller 29 that rotate while being pressed against each other. Yes.

  Further, the paper discharge unit 5 is for discharging the paper on which the toner image has been fixed in the fixing unit 4 to the outside of the apparatus main body 1a, and is provided in the middle of the vertical portion L2 of the paper transport path L. A plurality of transport rollers 30 and a paper discharge roller 31 provided at the end of the vertical portion L2 and a paper discharge tray 32 for stacking paper discharged outside the apparatus main body 1a are provided.

  The switchback unit 6 is used when an image is formed on both sides of a sheet. The switchback unit 6 includes another sheet conveyance path L ′ disposed below the vertical portion L1 of the sheet conveyance path L and the sheet conveyance path L ′. A plurality of conveying rollers 33 provided at appropriate positions are provided.

  Next, an image forming operation of the laser beam printer 1 having the above configuration will be described.

  For example, when a print start signal is transmitted to the laser beam printer 1 from a terminal such as a personal computer (personal computer), in the image forming unit 3, the photosensitive drum 21 is driven in a direction indicated by an arrow (clockwise) in FIG. ) And the surface thereof is uniformly charged to a predetermined potential by the primary charger 22. When a laser beam based on the image data transmitted from the terminal is output from the laser scanner unit 26 and irradiated onto the photosensitive drum 21, an electrostatic latent image is formed on the photosensitive drum 21. Then, the electrostatic latent image on the photosensitive drum 21 is developed by the developing device 23 using toner as a developer to be visualized as a toner image.

  At the same time, in the paper feeding unit 5, for example, the sheets stored in the paper feeding cassette 7 are picked up one by one from the uppermost one by the pickup roller 13, and the feed roller 14, the retard roller 15, and the paper feeding rollers 16, 17. , 18 are sent to the horizontal portion L1 of the paper transport path L, and after being temporarily put into a standby state by the registration roller 19, are supplied to the image forming portion 3 at a predetermined timing synchronized with the toner image on the photosensitive drum 21. The In the paper feed cassette 7, the bottom plate 10 is raised to a predetermined height position corresponding to the number of sheets stacked on the lift plate 9 by rotating the lift plate 9 away from the inner bottom surface. The uppermost one of the sheets stacked on the bottom plate 10 is picked up by the pickup roller 13. Further, when an image is formed on the paper loaded on the manual feed tray 8, the paper is taken out one by one by the pickup roller 20, and sent to the horizontal portion L1 of the transport path L by the paper feed rollers 16 and 18. .

  In the image forming unit 3, the sheet supplied to the transfer nip between the photosensitive drum 21 and the transfer roller 24 is conveyed while being pressed against the photosensitive drum 21 by the transfer roller 24, thereby its surface (transfer surface). ), The toner image on the photosensitive drum 21 is transferred. The sheet on which the toner image has been transferred is conveyed to the fixing unit 4, and is heated and pressed in the process of being sandwiched and conveyed by the heating roller 28 and the pressure roller 29 in the fixing unit 4. Get fixed. The toner remaining on the surface of the photosensitive drum 21 after transfer of the toner image onto the sheet (transfer residual toner) and electric charge are removed by the cleaning device 25.

  Thus, the sheet on which the toner image is fixed on the surface by the fixing unit 4 is conveyed upward by the conveying roller 30 along the vertical portion L2 of the sheet conveying path L, and is discharged to the upper part of the apparatus main body 1a by the discharge roller 31. The paper is discharged and stacked on the provided paper discharge tray 32.

  The above is a series of operations when an image is formed on one side of a sheet. When an image is formed on both sides of a sheet, a sheet on which a toner image is fixed on one side by a fixing unit 4 is conveyed by a conveyance roller 30. After the sheet is fed to the vertical portion L2 of the sheet conveyance path L, the sheet is switched back by reversing the conveyance roller 30 and is fed to the sheet conveyance path L ′ of the switchback unit 6. Then, the plurality of conveyance rollers 33 provided in the sheet conveyance path L ′ convey the sheet forward (to the right in FIG. 2) along the sheet conveyance path L ′, and the sheet is fed to the sheet feeding rollers 16, 17, When the sheet 18 is fed again to the horizontal portion L1 of the sheet conveying path L, the front and back sides of the sheet are reversed. When the toner image is transferred to the other surface and the toner image is fixed on the paper in the fixing unit 4, images are formed on both sides of the paper. The paper on which the images are formed on both sides in this way is transported upward along the vertical portion L2 of the paper transport path L by the transport roller 30 as described above, and is discharged to the paper discharge tray 32 by the paper discharge roller 31. .

  Next, the gist of the present invention will be described with reference to FIGS.

<Embodiment 1>
3 is a perspective view of the laser beam printer showing a state in which the paper feed cassette is removed, FIG. 4 is a side view of the paper transport path of the switchback unit, and FIG. 5 shows a state in which the lower paper guide of the paper transport path is opened. A side view and FIG. 6 are perspective views of the paper transport path.

  As shown in FIG. 4, the sheet transport path L ′ of the switchback unit 6 includes a solid-side sheet upper guide 35 and a movable-side sheet lower guide 36 disposed so as to be openable and closable below the sheet upper guide 35. It consists of and.

  Further, the rear end portion (left end portion in FIG. 4) of the lower sheet guide 36 is pivotally supported by a shaft 37 so as to be pivotable up and down, and the front end portion on the front side of the lower sheet guide 36. A gate-type hook stay 38 that is a paper hook portion is provided upright (at the right end portion in FIG. 4).

  Thus, the lower sheet guide 36 is biased upward by a torsion coil spring (not shown) wound around the shaft 37, and is closed as shown in FIG. A passage for conveying the sheet is formed between the guide 35 and the guide 35. When the images are formed on both sides of the paper, the paper that is switched back is conveyed toward the front surface side (right direction in FIG. 4) on the paper conveyance path L ′ as described above. The sheet passes through the inside of the gate-shaped hook stay 38 and is conveyed.

  Incidentally, as described above, when the paper is jammed while being transported on the paper transport path L ′, the paper feed cassette 7 is pulled out from the apparatus main body 1a as shown in FIG. Then, a hand is inserted into the apparatus main body 1a from an opening opening at the lower front of the apparatus main body 1a, and the front side of the sheet lower guide 36 in the sheet conveyance path L ′ is pushed down. Then, the lower sheet guide 36 pivots downward about the shaft 37 and opens as shown in FIGS. 5 and 6. At this time, the hook stay 38 provided in the lower sheet guide 36 moves the sheet P (see FIG. 5)), the jammed paper P can be easily removed.

  As described above, according to the present embodiment, it is possible to reliably perform the jam processing with a simple configuration in which the hook stay 38 is provided on the sheet lower guide 36.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIGS.

  7 is a side view of the sheet conveyance path of the switchback unit of the image forming apparatus according to the second embodiment of the present invention, FIG. 8 is an enlarged detail view of part A in FIG. 7, and FIG. 9 is a sheet lower guide in the sheet conveyance path. FIG. 10 is a perspective view of the main part of the lower sheet guide, FIG. 11 is a perspective view of a part of FIG. 10 broken away, and FIG. 12 is a partial perspective view of the state in which the lower sheet guide is opened by pushing the handle. It is.

  In the present embodiment, as shown in detail in FIG. 8, a hook 39 protrudes downward from the paper upper guide 35 in the paper conveyance path L ′, and as shown in FIG. A feature is that a handle 38 a is formed on a part of the hook stay 38 provided.

  In the present embodiment, the hooking stay 38 is rotatably supported at its both ends in the width direction on the left and right side walls of the sheet lower guide 36, and its one end is U-shaped as shown in FIG. Is bent at a right angle forward (to the right in FIG. 9), passes through a notch groove 36a formed on the front wall of the paper lower guide 36, and protrudes forward, and the protruding portion extends downward at a right angle. The bent portion is configured as a handle 38a. Therefore, as shown in FIGS. 9 and 10, the handle 38 a is exposed in a form that hangs vertically downward from the front wall at one end in the width direction of the sheet lower guide 36.

  The hook stay 38 is urged in one direction (direction engaged with the hook 39) by a torsion coil spring 40 wound around the hook stay 38, and the handle 38a formed on the hook stay 38 is placed under the sheet as shown in FIG. The guide 36 stands upright by engaging with the notch groove 36 a of the guide 36.

  Thus, at a normal time other than during jam processing, the sheet lower guide 36 is closed as shown in FIG. 7, and the sheet lower guide 36 is provided with a hook stay 38 provided on the sheet lower guide 36 on the sheet upper guide 35 side. The hook 39 is locked and fixed at the transport position. Then, when images are formed on both sides of the paper, the paper that has been switched back is conveyed toward the front side (right direction in FIG. 7) on the paper conveyance path L ′. Is passed through the inside of the hook stay 38.

  By the way, when a jam occurs due to the paper being transported along the paper transport path L ′, the paper feed cassette 7 is pulled out from the apparatus main body 1a and removed as in the first embodiment. Then, a hand is inserted into the apparatus main body 1a from the opening opening at the lower front of the apparatus main body 1a, and the handle 38a of the hook stay 38 is pushed downward as shown in FIG. Then, the hook stay 38 rotates against the urging force of the torsion coil spring 40, and the engagement with the hook 39 of the hook stay 38 is released as shown by a broken line in FIG. Pivots downward about the shaft 37 and opens.

  As described above, when the paper lower guide 36 is opened, the hook stay 38 provided on the paper lower guide 36 pulls out the paper while pulling out the paper, as in the first embodiment. Can be removed.

  When the jam processing is finished, when the lower sheet guide 36 is rotated upward about the shaft 37, the hook stay 38 provided on the lower guide 36 slides along the inclined surface 39a of the hook 39 shown in FIG. In order to automatically engage with the engaging groove 39b of the hook 39 after being tilted, the lower sheet guide 36 is locked and fixed to the hook 39.

  As described above, in this embodiment, in addition to the same effect as in the first embodiment, if the paper lower guide 36 is opened and jammed, and then the paper lower guide 36 is closed, Since the paper hooking stay 38 provided on the paper is locked by the hook 39 and the paper lower guide 36 is fixed at the transport position, the laser beam printer 1 is quickly returned to a state in which an image forming operation can be performed after the jam processing. The effect that it can be obtained.

  Further, according to the present embodiment, the user can easily perform the jam processing by gripping the handle 38a formed on the hook stay 38 during the jam processing and opening the sheet lower guide 36 with good workability.

  In the above, the embodiment in which the present invention is applied to a laser beam printer has been described. However, the present invention can be similarly applied to other arbitrary image forming apparatuses such as a copying machine and a facsimile machine in addition to a printer. Of course.

1 is a perspective view of an image forming apparatus (laser beam printer) according to the present invention. 1 is a side sectional view of an image forming apparatus (laser beam printer) according to the present invention. It is a perspective view of the laser beam printer which shows the state which pulled out the paper feed cassette in Embodiment 1 of this invention. FIG. 3 is a side view of the sheet conveyance path of the first embodiment of the present invention. 1 is a perspective view showing a state in which a space portion of a paper feeding cassette drawn out in front of an image forming apparatus (laser beam printer) according to the present invention is covered with a lid. Side view showing a state where the lower paper guide of the paper transport path is opened FIG. 10 is a side view of a sheet conveyance path of a switchback unit of an image forming apparatus according to Embodiment 2 of the present invention. 7 is an enlarged detail view of part A. FIG. FIG. 6 is a perspective view of a sheet lower guide in a sheet conveyance path. It is a perspective view of a paper lower guide main part. It is a perspective view which fractures | ruptures and shows a part of FIG. It is a fragmentary perspective view which shows a mode that a handle is pushed and a paper lower guide is opened.

Explanation of symbols

1 Laser beam printer (image forming device)
DESCRIPTION OF SYMBOLS 1a Device main body 2 Paper feed part 3 Image forming part 4 Fixing part 5 Paper discharge part 6 Switchback part 7 Paper feed tray 8 Manual feed tray 9 Lift plate 10 Lifting plate 11 Lift drive shaft 12 Shaft 13 Pickup roller 14 Feed roller 15 Retard roller 16 to 18 Paper feed roller 19 Registration roller 20 Pickup roller 21 Photosensitive drum 22 Primary charger 23 Developing device 24 Transfer roller 25 Cleaning device 26 Laser scanner unit (LSU)
27 Toner Hopper 28 Heating Roller 29 Pressure Roller 30 Conveying Roller 31 Discharge Roller 32 Discharge Tray 33 Conveying Roller 34 Operation Display Unit 35 Paper Upper Guide (Fixed Side Paper Guide)
36 Lower paper guide (movable paper guide)
36a Notch groove of lower paper guide 37 Axis 38 Hook stay (paper hook)
38a Handle 39 Hook 39a Hook inclined surface 39b Hook engagement groove 40 Torsion coil spring L, L 'Paper transport path L1 Horizontal section of paper transport path L2 Vertical section of paper transport path P Paper

Claims (4)

In the image forming apparatus configured to perform jamming by opening the movable side paper guide in a paper conveyance path having a fixed side paper guide and a movable side paper guide.
An image forming apparatus, wherein a paper hooking portion for pinching and pulling out jammed paper is provided on the movable paper guide.   The image forming apparatus according to claim 1, wherein the paper hooking unit is configured by a gate-type hook stay standing upright across the entire width of the movable paper guide on the paper transport surface side.   3. The image forming apparatus according to claim 1, wherein the fixed side paper guide is provided with a hook, and the movable side paper guide is fixed at the transport position by engaging the paper hooking portion with the hook.   The image forming apparatus according to claim 1, wherein a handle for opening the movable side paper guide is formed in the paper hooking portion.

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