JP2009282470A - Sheet guiding device, fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a sheet guiding device capable of reducing an opening/closing noise generated, when a switching gate is moved with rotation by suppressing the rotational movement amount of the switching gate, and to obtain a fixing device and an image forming apparatus. <P>SOLUTION: When a weak sheet member P is sent out from a heat roll 90 and a pressure roll 92 toward a first guiding surface 98, the sheet member P is guided by the first guiding surface 98, then the switching gate 94 is moved with rotation by the amount of the thickness of the sheet member P. Meanwhile, when a stiff sheet member P is sent toward the first guiding surface 98, the switching gate 94 is moved with rotation about the rotating shaft member 102, by a pressurizing force applied from the sheet member P, to the first guiding surface 98, then, the terminal part 100 is opened; and the opening/closing noise due to the rotational movement of the switching gate can be reduced, by suppressing the rotational movement amount of the switching gate 94, as compared with the case where the sheet member P is guided, while the rotational movement amount constant is kept fixed. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a sheet guide device that guides a sheet, a fixing device including the sheet guide device, and an image forming apparatus.

  Patent Document 1 describes a configuration in which a recording medium on which a toner image is fixed by a fixing device is transported in a discharge direction by pushing up a gate.

Here, a sensor is provided at the gate so that the passage of the recording medium can be detected. Specifically, when the recording medium passes through the gate (guide member), the gate (guide member) is similarly rotated and moved to open and close the terminal portion of the gate member (guide member). Detects passing. In this manner, the conveyance control of the recording medium is performed by detecting the passage of the recording medium through the gate (guide member) by opening and closing the terminal portion of the gate (guide member).
JP 2005-41635 A

  An object of the present invention is to reduce an opening / closing sound accompanying the rotational movement by suppressing the rotational movement amount of the guide member.

  A sheet guide apparatus according to claim 1 of the present invention is provided on a guide member and guides the sheet downstream while changing the transport direction of the transported sheet, and sheet transport together with the first guide surface. A guide portion constituting a path, and a rotating shaft portion that rotatably supports the guide member so that the first guide surface and the guide portion are separated when the guided sheet presses the first guide surface; The amount of rotational movement of the first guide surface varies based on the strength of the waist of the seat guided by the first guide surface.

  A sheet guide device according to a second aspect of the present invention is provided on a guide member, a first guide surface that guides the sheet downstream while changing a transport direction of the transported sheet, and a sheet transport together with the first guide surface. A guide portion constituting a path, and a rotating shaft portion that rotatably supports the guide member so that the first guide surface and the guide portion are separated when the guided sheet presses the first guide surface; The first guide surface and the guide portion are separated from each other with a predetermined gap in a state where the conveyed sheet does not press the first guide surface.

  The sheet guide device according to claim 3 of the present invention is the sheet guide device according to claim 1 or 2, wherein the guide member receives a sheet conveyed from the downstream position of the first guide surface to the guide member. The second guide surface functions to guide the sheet downstream of the second guide surface in a state where the conveyed sheet does not press the first guide surface.

  According to a fourth aspect of the present invention, in the sheet guide device according to the first aspect, when the first guide surface guides a sheet having a weak waist, the guide member rotates and moves by the thickness of the sheet. Features.

  The sheet guide device according to claim 5 of the present invention is characterized in that, in claim 2, when the first guide surface guides a sheet with low stiffness, the guide member does not rotate.

  A fixing device according to a sixth aspect of the present invention includes a heating member, a pressure member that presses a sheet on which the unfixed toner image is formed on the heating member, and a toner image that is pressed against the heating member by the pressure member. And a sheet guiding device according to any one of claims 1 to 5, which guides the sheet on which the toner is fixed.

  An image forming apparatus according to a seventh aspect of the present invention includes the sheet guiding apparatus according to any one of the first to sixth aspects.

  According to the configuration of the first aspect of the present invention, the rotational movement amount of the guide member changes based on the strength of the waist of the sheet guided by the first guide surface. For this reason, it is possible to reduce the opening / closing noise associated with the rotational movement by suppressing the rotational movement amount of the guide member, as compared with the case where the guide member is always rotated and moved in the same way when the sheet is guided. it can.

  According to the configuration of the second aspect of the present invention, since the first guide surface and the guide portion are separated with a predetermined gap, a sheet having a thickness equal to or less than the predetermined gap can be obtained without rotating the guide member. In some cases, it can be transported downstream, and in that case, it is possible to reduce open / close noises accompanying rotational movement.

  According to the configuration of claim 3 of the present invention, the guide member has the first guide surface and the second guide surface, and the second guide surface functions when the first guide surface does not press the sheet. The guide device can be reduced in size.

  According to the configuration of the fourth aspect of the present invention, the guide member rotates only by the thickness of the recording medium when guiding a sheet having a low waist. The amount of rotational movement can be further suppressed.

  According to the configuration of the fifth aspect of the present invention, when guiding a seat with a weak waist, the guide member does not rotate, so that it is possible to prevent the occurrence of opening / closing noises accompanying the rotational movement.

  According to the configuration of claim 6 of the present invention, the guide member rotates and moves on the basis of the strength of the waist of the sheet so that the first guide surface escapes from the sheet. Damage to the sheet after fixing can be suppressed by the member and the pressure member.

  According to the configuration of the seventh aspect of the present invention, it is possible to obtain an image forming apparatus in which the opening / closing sound accompanying the rotational movement of the guide member is reduced.

  An example of an image forming apparatus employing the guide member according to the first embodiment of the present invention will be described with reference to FIGS.

(overall structure)
As shown in FIG. 9, in the image forming apparatus 10, process cartridges 14 of four colors (in this embodiment, yellow, magenta, cyan, and black) are arranged in the vertical direction. Further, the process cartridge 14 includes a photoconductor cartridge 62 having the photoconductor 16 and a developing cartridge 64.

  As shown in FIG. 8, the photoconductor cartridge 62 is arranged in the lateral direction of the photoconductor 16 and the cleaning device 22, the charging roll 18, the erase lamp 24, and the cleaning device 22 disposed around the photoconductor 16. And a sub-toner replenishment unit 66 provided.

  The sub-toner supply unit 66 is provided with a pair of support protrusions 78 extending in a direction orthogonal to the axial direction of the photoconductor 16. By inserting the support protrusion 78 into a cartridge receiving portion (not shown) of the image forming apparatus 10, the process cartridge 14 is mounted on the image forming apparatus 10.

  Further, a developing roll 86 for developing the electrostatic latent image on the photosensitive member 16 into a toner image with the developer G is disposed in the developing cartridge 64 so as to face the photosensitive member 16. Further, below the developing roll 86, a first agitation transport auger 88 and a second agitation transport auger 89 for supplying the developer G stored in the developer storage chamber 84 to the developing roll 86 are disposed.

  As a result, the developer G supplied from the first agitating and conveying auger 88 and the second agitating and conveying auger 89 adheres onto the developing roll 86, and the developing roll 86 conveys the developer G to a position facing the photoreceptor 16. To do. The electrostatic latent image formed on the photosensitive member 16 is visualized as a toner image by the developer G on the developing roll 86.

  Further, as shown in FIG. 9, the process cartridge 14 is arranged in order of yellow, magenta, cyan, and black from the upstream side of the paper transport path 34. An exposure device 36 for irradiating the process cartridge 14 with scanning light is disposed.

  A semiconductor laser (not shown), a polygon mirror 40, an imaging lens 44, and a mirror 46 are disposed in the housing 38 of the exposure device 36, and light from the semiconductor laser is deflected and scanned by the polygon mirror 40. The photosensitive member 16 is irradiated through the imaging lens 44 and the mirror 46. As a result, an electrostatic latent image corresponding to the image data is formed on the photosensitive member 16.

  Further, a transport unit 48 is disposed at a position facing the photoconductor 16 across the paper transport path 34. The transport unit 48 includes a pair of stretching rolls 51 and 52 provided along the side wall 10 </ b> A of the image forming apparatus 10, and a transport belt 53 wound around the stretching rolls 51 and 52. The tension roll 52 is rotated by a motor (not shown) so that the conveyor belt 53 moves.

  An adsorption roll 55 is disposed in the vicinity of the tension roll 51, and a sheet member P as a recording medium is electrostatically adsorbed to the conveyance belt 53 by applying a voltage to the adsorption roll 55. It has become so.

  Further, a transfer roll 54 is disposed on the back surface of the conveyance belt 53 at a position facing the photoconductor 16 of each color, and the transfer roll 54 and the photoconductor 16 constitute an image forming unit 74. In the image forming unit 74, the toner image on the photoconductor 16 is transferred to the sheet member P conveyed by the conveyance belt 53.

  In addition, a paper feed cassette 26 in which the sheet member P is stored is provided at the lower part of the image forming apparatus 10. Further, a pickup roll 28 for feeding the sheet member P at a predetermined timing is provided in the vicinity of the paper feed cassette 26. The sheet member P sent out from the paper feed cassette 26 by the pickup roll 28 is transported by a plurality of transport rolls 30 and a registration roll 32 provided in the transport apparatus 70 and is sent out to the paper transport path 34 at a predetermined timing. The sheet member P sent to the sheet conveyance path 34 is transferred with a toner image by the image forming unit 74 of each color, and the toner image is fixed to the sheet member P by the fixing device 56. Then, the sheet member P on which the toner image is fixed is discharged to the discharge tray 60 by an exit roll 58 provided in the fixing device 56. Details of the fixing device 56 will be described later.

  Further, on the side opposite to the process cartridge 14 of the transport unit 48, after the sheet member P is transported to the image forming unit 74 again with the front and back sides of the sheet member P having the image fixed on one side by the fixing device 56 reversed. A reversing unit 68 as a processing apparatus is provided, and the reversing unit 68 is provided with a reversing conveyance path 50.

  A plurality of conveyance rolls 72 that convey the sheet member P to be reversed are disposed in the reverse conveyance path 50, and the sheet member P is conveyed on the reverse conveyance path 50 by the conveyance roll 72 and is provided in the conveyance device 70. The resist roll 32 is sent again to the image forming unit 74 at a predetermined timing.

  In the image forming apparatus 10 configured as described above, an image is formed as follows.

  As shown in FIG. 9, first, the charging roll 18 to which a voltage is applied uniformly charges the surface of the photoconductor 16 at a predetermined charging portion potential.

  Further, exposure is performed by the exposure device 36 so that the image portion on the charged photoconductor 16 has a predetermined exposure portion potential, and an electrostatic latent image is formed.

  That is, based on image data supplied from a control device (not shown), a semiconductor laser (not shown) is turned on / off and modulated to form a latent image corresponding to the image on the photoconductor 16.

  Further, as shown in FIG. 8, the developer G stirred and conveyed by the first agitating and conveying auger 88 and the second agitating and conveying auger 89 of the developing cartridge 64 is supplied to the developing roll 86, and the developer G is developed. It is attracted onto the developing roll 86 by the magnetic force of the roll 86. The adsorbed developer G is conveyed to a position facing the photoconductor 16 by the developing roller 86.

  A predetermined developing bias voltage is applied to the developing roll 86 for each color from a power supply device (not shown), and when the electrostatic latent image on the photosensitive member 16 passes the position of the developing roll 86, the developer G The toner adheres by electric force and is visualized as a toner image.

  Therefore, the sheet member P accommodated in the paper feed cassette 26 shown in FIG. 9 is sent to the paper conveyance path 34 by the pickup roll 28, and further, by the registration roll 32 provided in the conveyance roll 30 and the conveyance device 70. The toner image on the photosensitive member 16 is transferred to the sheet member P by being conveyed to the image forming unit 74 at a predetermined timing. The transferred toner image is fixed by the fixing device 56, and the sheet member P on which the toner image is fixed is discharged to the discharge tray 60 by the exit roll 58.

(Main part)
Next, the fixing device 56 will be described.

  As shown in FIG. 7, the fixing device 56 is a unit that is detachable from the image forming apparatus 10 (see FIG. 9). Further, as shown in FIG. A heating roll 90 serving as a heating member provided with a heat source therein and driven to rotate, and a pressure roll 92 serving as a pressure member disposed opposite to the heating roll 90 and pressed against the heating roll 90 are provided. ing. Further, a switching gate 94 as a substantially triangular guide member is provided downstream of the heating roll 90 and the pressure roll 92 in the conveying direction, as viewed from the side constituting the sheet guide device 93.

  As shown in FIG. 1, the switching gate 94 is provided with a first guide surface 98 that guides the sheet member P fed from the heating roll 90 and the pressure roll 92 toward the exit roll 58. A rotating shaft member 102 is provided that rotatably supports the switching gate 94 so that the terminal end portion 100 of the first guide surface 98 that contacts the guide portion 80 provided in the apparatus main body is separated from the guide portion 80.

  In addition, a pinch roll 104 that is disposed opposite to the exit roll 58 and the exit roll 58 and presses the transported sheet member P against the exit roll 58 is provided downstream of the end portion 100 in the transport direction. Further, the exit roll 58 is provided so as to be able to rotate forward and backward by receiving a driving force from a driving member (not shown). When the exit roll 58 rotates forward (in the direction of arrow B in the figure), the sheet member P is It is discharged to a discharge tray 60 (see FIG. 9).

  Further, in the switching gate 94, on the opposite side of the first guide surface 98, a second guide surface 106 for guiding the sheet member P conveyed by the reversely rotating exit roll 58 to the reversing unit 68 (see FIG. 9) is formed. Has been. The second guide surface 106 can guide the sheet member P to the reversing unit 68 (see FIG. 9) at the initial position of the switching gate 94 where the end portion 100 is closed (in contact with the guide portion 80). It is formed so that.

  That is, when the rear end of the sheet member P guided to the exit roll 58 by the first guide surface 98 passes through the terminal end portion 100, the exit roll 58 that has been normally rotated reversely rotates and causes the sheet member P to run backward. The sheet member P running backward is sent out to the reversing unit 68 (see FIG. 9) by the second guide surface 106.

  Here, the 1st guide surface 98 etc. which guide the sheet | seat member P sent out from the heating roll 90 and the pressure roll 92 are demonstrated in detail.

  In the present embodiment, when the first guide surface 98 guides the sheet member P having a low waist, the switching gate 94 is centered on the rotary shaft member 102 by the thickness of the sheet member P that allows the sheet member P to pass therethrough. The position of the rotary shaft member 102, the shape and weight of the switching gate 94, the guide direction, and the like are determined so that the sheet member P is sent out from the terminal portion 100 toward the exit roll 58.

  On the other hand, when the first guide surface 98 guides the sheet member P having a strong waist, the switching gate 94 rotates around the rotary shaft member 102 by the pressing force that the first guide surface 98 receives from the sheet member P. The end portion 100 is opened away from the guide portion 80. The position of the rotary shaft member 102 and the shape of the switching gate 94 are determined so that the sheet member P is sent out from the opened terminal end 100 toward the exit roll 58. That is, the rotational movement amount of the switching gate 94 changes based on the waist strength of the sheet member P guided by the first guide surface 98.

Further, the strength of the waist is caused by the basis weight of the sheet member P (mass per unit area: JIS P-8124). In this embodiment, the basis weight is 52 to 105 [g / m ² ]. A weak sheet member P (plain paper) is used, and a basis weight of 127 to 216 [g / m ² ] is a strong sheet member P (thick paper).

(Function)
Next, a case where images are formed on both surfaces of the sheet member P will be described.

  As shown in FIG. 1, when the sheet member P having a low waist is fed from the heating roll 90 and the pressure roll 92 toward the first guide surface 98, the first guide surface 98 guides the sheet member P and switches. The gate 94 is rotated by the thickness of the sheet member P. When the switching gate 94 rotates and moves by the thickness of the sheet member P, the sheet member P is sent out from the terminal portion 100 toward the exit roll 58 that rotates in the forward direction (the direction of arrow B in the figure). Upon receiving the sheet member P, the exit roll 58 that rotates in the forward direction conveys the sheet member P toward the downstream in the conveyance direction.

  As shown in FIG. 2, when the rear end portion of the sheet member P conveyed toward the downstream in the conveying direction by the exit roll 58 passes through the terminal end portion 100, the switching gate 94 rotates by the thickness of the sheet member P. The terminal portion 100 is closed and the switching gate 94 returns to the initial position. That is, since the switching gate 94 rotates and moves only by the thickness of the sheet member P, the terminal portion 100 returns to the initial position without being largely opened. When the rear end portion of the sheet member P passes through the terminal end portion 100, the exit roll 58 rotates in the reverse direction (the direction of arrow C in the figure).

  As shown in FIG. 3, when the exit roll 58 rotates in the reverse direction, the sheet member P runs backward and the rear end portion of the sheet member P hits the second guide surface 106. Since the switching gate 94 has returned to the initial position, the second guide surface 106 guides the sheet member P fed from the exit roll 58 to the reversing unit 68 (see FIG. 9).

  On the other hand, as shown in FIG. 4, when the strong sheet member P is sent from the heating roll 90 and the pressure roll 92 toward the first guide surface 98, the first guide surface 98 moves the sheet member P away. Guide to exit roll 58. The switching gate 94 is rotated about the rotary shaft member 102 by the pressing force received by the first guide surface 98 from the sheet member P, and the terminal portion 100 is opened. Since the switching gate 94 rotates and the terminal portion 100 is opened, the sheet member P is not loaded with an excessive force. And the sheet | seat member P is sent out toward the exit roll 58 which rotates to the normal direction (arrow B direction in a figure) from the open | released terminal part 100. FIG.

  Upon receiving the sheet member P, the exit roll 58 that rotates in the forward direction conveys the sheet member P toward the downstream in the conveyance direction.

  As shown in FIG. 5, when the rear end portion of the sheet member P conveyed by the exit roll 58 toward the downstream in the conveying direction passes through the termination portion 100, the opened termination portion 100 is closed and the switching gate 94 is Return to the initial position. Further, when the rear end portion of the sheet member P passes through the terminal end portion 100, the exit roll 58 rotates in the reverse direction (the direction of arrow C in the figure).

  As shown in FIG. 6, when the exit roll 58 rotates in the reverse direction, the sheet member P runs backward and the rear end portion of the sheet member P hits the second guide surface 106. Since the end portion 100 is closed and the switching gate 94 is returned to the initial position, the second guide surface 106 guides the sheet member P to the reversing unit 68 (see FIG. 9).

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. It is clear to the contractor. For example, in the above-described embodiment, the reversing unit 68 has been described as an example of the post-processing device. However, a sorter, a punch, a staple, or the like may be used.

  In the above embodiment, the basis weight is used as an index for determining the strength of the waist, but an index such as material and bending rigidity may be used.

  In the above embodiment, the fixing device using the sheet guide device has been described as an example. However, the fixing device may be applied to any device as long as the guide member is configured to be movable.

  Next, an example of an image forming apparatus employing the guide member according to the second embodiment of the present invention will be described with reference to FIG.

  In addition, about the same member as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 10, in the sheet guide device 110 according to the second embodiment, unlike the first embodiment, a gap that allows the sheet member P having a low waist to pass is formed in advance with the terminal portion 100 of the switching gate 94 and the guide. It is provided between the parts 80.

  Specifically, protrusions (not shown) are formed at both end portions of the guide member 80 through which the sheet member P does not pass toward the end portion 100, and the sheet is formed by applying the tip end portion of the protrusion portion to the end portion. A gap for allowing the member P to pass therethrough is provided.

  Further, in the second embodiment, when the first guide surface 98 guides the seat member P having a weak waist, the position of the rotary shaft member 102 and the shape and weight of the switching gate are prevented so that the switching gate 94 does not rotate. The guidance direction is determined.

  Thereby, even if the switching gate 94 does not rotate, the sheet member P having a low waist passes through the terminal portion.

1 is a cross-sectional view showing a fixing device employing a sheet guide device according to a first embodiment of the present invention, and showing a state where a sheet member having a low waist is conveyed. 1 is a cross-sectional view showing a fixing device employing a sheet guide device according to a first embodiment of the present invention, and showing a state where a sheet member having a low waist is conveyed. 1 is a cross-sectional view showing a fixing device employing a sheet guide device according to a first embodiment of the present invention, and showing a state where a sheet member having a low waist is conveyed. 1 is a cross-sectional view showing a fixing device employing a sheet guide device according to a first embodiment of the present invention, and showing a state in which a stiff sheet member is conveyed. 1 is a cross-sectional view illustrating a fixing device in which a sheet guide device according to a first embodiment of the present invention is employed, and showing a state in which a stiff sheet member is conveyed. 1 is a cross-sectional view showing a fixing device employing a sheet guide device according to a first embodiment of the present invention, and showing a state in which a stiff sheet member is conveyed. 1 is a perspective view illustrating a fixing device in which a sheet guide device according to a first embodiment of the present invention is employed. 1 is a cross-sectional view illustrating a process cartridge of an image forming apparatus employing a fixing device employing a sheet guiding device according to a first embodiment of the present invention. 1 is a schematic configuration diagram illustrating an image forming apparatus employing a fixing device employing a sheet guiding device according to a first embodiment of the present invention. FIG. 9 is a cross-sectional view illustrating a fixing device in which a sheet guide device according to a second exemplary embodiment of the present invention is employed, and illustrating a state where a sheet member is not conveyed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 56 Fixing apparatus 80 Guide part 90 Heating roll (heating member)
92 Pressure roll (Pressure member)
93 Sheet guide device 94 Switching gate (guide member)
98 First guide surface 100 Terminal portion 102 Rotating shaft member (Rotating shaft portion)
106 Second guide surface 110 Sheet guide device

Claims (7)

A first guide surface that is provided on the guide member and guides the sheet downstream while changing the transport direction of the transported sheet;
A guide portion that forms a sheet conveyance path together with the first guide surface;
A rotating shaft portion that rotatably supports the guide member so that the first guide surface and the guide portion are separated when the guided sheet presses the first guide surface;
The sheet guide device in which a rotational movement amount of the guide member changes based on a waist strength of the sheet guided by the first guide surface. A first guide surface that is provided on the guide member and guides the sheet downstream while changing the transport direction of the transported sheet;
A guide portion that forms a sheet conveyance path together with the first guide surface;
A rotating shaft portion that rotatably supports the guide member so that the first guide surface and the guide portion are separated when the guided sheet presses the first guide surface;
The sheet guide device in which the first guide surface and the guide portion are separated from each other with a predetermined gap in a state where the conveyed sheet does not press the first guide surface. The guide member has a second guide surface that receives a sheet conveyed from the downstream position on the first guide surface to the guide member;
3. The sheet guide device according to claim 1, wherein the second guide surface functions to guide the sheet downstream of the second guide surface in a state where the conveyed sheet does not press the first guide surface.   The sheet guide device according to claim 1, wherein when the first guide surface guides a sheet with low stiffness, the guide member rotates and moves by the thickness of the sheet.   The sheet guide device according to claim 2, wherein when the first guide surface guides a weak seat, the guide member does not rotate. A heating member;
A pressure member for pressing a sheet on which an unfixed toner image is formed on the heating member;
The sheet guide device according to any one of claims 1 to 5, which guides a sheet on which a toner image is fixed by being pressed against the heating member by the pressure member.
A fixing device.   An image forming apparatus comprising the sheet guiding apparatus according to claim 1.

Images