JP2004189426A - Sheet carrier and fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent breakage of a fixing device caused by any operation error of a user. <P>SOLUTION: A fixing device has a lever 81 to separate a pressure belt 70 from a heating roll 60, and a knob 90 to manually rotate the heating roll 60. In a condition in which the heating roll 60 and the pressure belt 70 are pressed against each other by operating the lever 81, a knob 90 is covered by a cover member 87 integrally fitted to the lever 81, and the knob 90 is not operated thereby. On the other hand, in a condition in which the pressure belt 70 is separated from the heating roll 60 by operating the lever 81, the knob 90 is not covered by the cover member 87, the heating roll 60 is rotated by operating the knob 90 by the user and jammed paper sheets can be removed thereby. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet conveying device that conveys a sheet and a fixing device that fixes an unfixed image formed on the sheet.
[0002]
[Prior art]
2. Description of the Related Art In image forming apparatuses such as copiers, printers, and facsimile machines, a toner image formed on a photosensitive drum or the like is directly or indirectly transferred onto a sheet, and an unfixed toner image transferred on the sheet is heated and pressed and fixed. By doing so, a permanent image is formed on the paper. In such an image forming apparatus, a paper transport device that transports paper while holding the paper in a nip portion between a pair of transport rolls is provided. Further, as a fixing device for heating and pressure fixing an unfixed toner image on a sheet, for example, a heating roll having a heating source therein and a pressure roll pressed against the heating roll are provided. 2. Description of the Related Art There is known an apparatus in which a sheet is made to pass through a nip portion with a roll.
[0003]
In such a paper transport apparatus, when a paper jam occurs during paper transport, it is necessary to remove the paper sandwiched between the nip portions. Then, what attached the removal knob which rotates one conveyance roll manually is known. However, since the transport roll is connected to a power transmission mechanism (a drive motor or a gear, etc.) in the image forming apparatus, or the transport roll pair may be pressed against a high load, the removal roll is rotated. The required torque can be very large. In particular, in the above-described fixing device, since the heating roll and the pressure roll are pressed against each other with a high load, the paper removal force required when a paper jam occurs (to rotate the removal knob) is more required than a general transport roll pair. The required force) increases. For this reason, stress is applied to the drive transmission unit (gear, shaft, etc.) from the removal knob to the heating roll or the pressure roll, and these may be damaged. Further, if the user cannot turn the removal knob because the paper removing force is too large, there is a risk that the paper may remain in the fixing device or the paper may be broken in an attempt to forcibly remove the paper.
[0004]
Therefore, a separation lever for separating the heating roll and the pressure roll is provided (see Patent Documents 1 and 2), and the heating roll and the pressure roll are separated from each other in conjunction with the operation of pulling out the fixing device from the image forming apparatus. (See Patent Document 3).
[0005]
[Patent Document 1]
Japanese Utility Model Application Laid-Open No. 4-46559 (pages 8-10)
[Patent Document 2]
JP-A-2-261773 (page 3)
[Patent Document 3]
JP-A-62-258483 (pages 2-3, FIGS. 4 and 5)
[0006]
[Problems to be solved by the invention]
By the way, even if the heating roll and the pressure roll are separated by the separation lever, if the paper that caused the paper jam is not visible outside the fixing device, the paper cannot be removed. become.
That is, the separation lever is operated to separate the heating roll and the pressure roll, and then the removal knob is rotated to discharge the paper out of the fixing device. The paper can be removed.
[0007]
However, when the separation lever and the removal knob are attached to the fixing device, there is a problem that the user does not know which of the separation lever and the removal knob should be operated first. That is, it is possible to solve the problem that the user may operate in the reverse of the above-described procedure, and if the removal knob is operated first, the drive transmission unit of the heating roll or the pressure roll may be damaged. Can not.
In order to solve such a problem, it is possible to display an operation procedure by attaching a guide label for the user to the image forming apparatus, but cannot cope with an erroneous operation by the user.
[0008]
The present invention has been made to solve the above technical problems, and an object of the present invention is to prevent damage to a device due to a user's erroneous operation.
Another object of the present invention is to reduce the size of the device.
[0009]
[Means for Solving the Problems]
The present invention proposes a configuration for allowing a user to perform operations in a correct order.
That is, the sheet conveying apparatus of the present invention includes a conveying unit that nip-conveys a sheet by using a pair of conveying members that are arranged in press contact, a pressing force applying unit that applies a pressing force to the conveying unit, and a pressing force applying unit. And a manual drive unit configured to be operable after the operation of the pressing force changing unit is manually performed, and configured to be operable after operating the pressing force changing unit. In such a sheet conveying apparatus, the pressing force changing unit has a lever that is swingably disposed, and the manual driving unit has a knob that is rotatably disposed. In this case, the swing center of the lever and the rotation center of the knob may be the same.
[0010]
Further, the sheet conveying device of the present invention includes a conveying member rotatably disposed, an opposing conveying member rotatably pressed against the conveying member, and a pressing force acting between the conveying member and the opposing conveying member. An adjusting member for adjusting, a driving member for manually driving the conveying member, and an operating member for exposing the driving member in an operable state in conjunction with an operation of weakening or releasing the pressing force by the adjusting member; And a cover member that covers the driving member in an inoperable state in conjunction with the operation of increasing or adding the pressing force. In such a sheet conveying apparatus, the driving member is rotatably provided, the adjusting member is swingably disposed, and the rotation center of the driving member and the swing center of the adjusting member are the same. Can be characterized. In addition, the cover member is provided so as to be swingable about the swing center.
The cover member is fixedly arranged and fixedly covers a part of the driving member, and is formed integrally with the adjusting member, and exposes or covers the driving member in conjunction with the operation of the adjusting member. And a moving cover. Further, the relative positions of the driving member and the cover member change in the axial direction in conjunction with the operation of the adjustment member.
[0011]
Further, the sheet conveying device of the present invention includes a conveying unit that nip-conveys the sheet by using a pair of conveying members that are arranged in press contact, a pressing force adjusting unit that adjusts the pressing force of the pair of conveying members, and a manual conveying unit. And a manual driving means driven by the control means, and when the pressing force is weakened or released by the pressing force adjusting means, the manual driving means can be accessed. Such a sheet conveying apparatus can be characterized in that the manual driving means cannot be accessed when the pressing force is increased or added by the pressing force adjusting means.
[0012]
Further, the fixing device of the present invention includes a heating member having a heating source and rotatably disposed, and a recording medium rotatably pressed against the heating member and carrying an unfixed toner image between the heating member and the heating member. A pressing member that is nipped and conveyed, a pressing force adjusting mechanism that adjusts a pressing force that acts between the heating member and the pressing member, and a manual driving mechanism for manually driving the heating member or the pressing member. , The manual drive mechanism is exposed to an operable state in conjunction with the operation of weakening or releasing the pressing force by the pressing force adjusting mechanism, and the manual driving mechanism is manually operated in conjunction with the operation of increasing or adding the pressing force by the pressing force adjusting mechanism. And a cover for covering the drive mechanism in an inoperable state. In such a fixing device, the pressing member is formed of an endless pressing belt, and a pressing member for pressing the pressing belt toward the heating member is provided inside the pressing belt. be able to. The pressing force adjusting mechanism has a lever for moving the pressing member, and the manual driving mechanism has a knob for rotating the heating member, and the lever and the knob are arranged so as to rotate about the same axis. It can be characterized. The cover has a fixed cover that is fixedly arranged and covers a part of the knob constantly, and a moving cover that is formed integrally with the lever and that exposes or covers the knob in conjunction with the operation of the lever. Can be characterized. Further, the relative positions of the knob and the cover change in the axial direction in conjunction with the operation of the lever.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.
-Embodiment 1-
FIG. 1 is a diagram illustrating an entire configuration of the image forming apparatus 1 according to the first embodiment. The image forming apparatus 1 has a user interface UI and a transparent platen glass 2 on which a document (not shown) is placed. The user interface UI has a copy start key, a paper type designation key, a numeric keypad, a display, and the like (all not shown).
[0014]
Below the platen glass 2, a document illumination unit 3 that includes a light source 4 that irradiates the document and a first reflection mirror 5 that reflects light reflected from the document and is movable in the horizontal direction in FIG. A mirror unit 6 including a second reflection mirror 7 and a third reflection mirror 8 is fixedly disposed on a side of the first reflection mirror 5. An imaging lens 9 and an imaging unit CCD (Charge Coupled Device) are provided on the path of the light reflected by the reflection mirror 8. The imaging unit CCD reads reflected light from the document as analog signals of R (red), G (green), and B (blue). An image processing unit IPS (Image Processing System) controlled by a controller (not shown) is connected to the imaging unit CCD. The image processing unit IPS has an image reading data output unit 11 for AD-converting a reading image signal input from the imaging unit CCD, and an image memory 13, and data (digital data) output from the image reading data output unit 11 Is converted into image data of Y (yellow), M (magenta), C (cyan), and K (black) to perform data processing such as density correction and enlargement / reduction correction, and write image data (laser drive data). ) And an image data output unit 12 for outputting the image data.
[0015]
The image processing unit IPS includes a laser drive signal output device 14 that outputs a laser drive signal corresponding to the write image data output from the image processing unit IPS to an optical scanning device ROS (Raster Output Scanner) at a predetermined timing. It is connected. The optical scanning device ROS outputs a laser beam L modulated by a laser drive signal and irradiates the photosensitive drum 16 rotating in the direction of arrow A.
[0016]
Around the photoreceptor drum 16, a charger 17 and developing units 18Y, 18M, 18C, and 18K each containing the toner T corresponding to each color of the optical scanning devices ROS, Y, M, C, and K described above are mounted. A rotary developing device 18 that rotates around a rotation shaft 18a and a drum cleaner 20 that removes the toner T remaining on the photosensitive drum 16 after the primary transfer are provided. In the present embodiment, the photosensitive layer of the photosensitive drum 16 is configured to be negatively charged, and development is performed by a reversal development method. Therefore, the used toner T has a characteristic that is easily charged to a negative polarity.
[0017]
The photosensitive drum 16 is provided with an intermediate transfer belt 21 arranged so as to contact the surface of the photosensitive drum 16. The intermediate transfer belt 21 is wound around a plurality of rolls 26, 27, 28a to 28c, and 29, and rotates in the direction of arrow B. Among these, the roll 26 is a driving roll for rotating the intermediate transfer belt 21, the roll 27 is a tension roll for keeping the tension applied to the intermediate transfer belt 21 constant, the rolls 28 a to 28 c are idler rolls that are driven to rotate, The roll 29 is a backup roll for secondary transfer described later. Here, the idler roll 28a is formed of a grounded metal roll.
[0018]
Further, at a portion (primary transfer position) of the intermediate transfer belt 21 opposed to the photosensitive drum 16, a primary transfer device (primary transfer roll in this example) T <b> 1 is disposed on the back side of the intermediate transfer belt 21. The primary transfer roll T <b> 1 is driven to rotate with the rotation of the intermediate transfer belt 21.
[0019]
Further, a secondary transfer device T2 is disposed at a secondary transfer position of the intermediate transfer belt 21 facing the transport path of the sheet S. The secondary transfer device T2 includes a secondary transfer roll 30 disposed on the toner T carrying surface side (outside) of the intermediate transfer belt 21 so as to be able to contact and separate from the intermediate transfer belt 21, and a back side (inside) of the intermediate transfer belt 21. ), And a backup roll 29 serving as a counter electrode of the secondary transfer roll 30, and a metal power supply roll 31 disposed in pressure contact with the backup roll 29. The backup roll 29 is formed by winding a semiconductive elastic body around a conductive metal roll, and its surface resistivity is adjusted to, for example, 7 logΩ / □ or more. On the other hand, the secondary transfer roll 30 is formed by wrapping the surface of a metal roll with carbon-dispersed urethane foam and wrapping a semiconductive elastic body around the outside thereof. For example, the volume resistivity is adjusted to 9 logΩcm. I have. The secondary transfer roll 30 is provided with a roll cleaner 33 for removing foreign substances such as toner adhered to the secondary transfer roll 30.
[0020]
Further, a belt cleaner 34 is disposed downstream of the secondary transfer device T2 at a position facing the idler roll 28a with the intermediate transfer belt 21 interposed therebetween. The belt cleaner 34 is disposed so as to be able to freely contact and separate from the intermediate transfer belt 21, and when a color toner image of a plurality of colors is formed, the toner image before the final color is opposed to the belt cleaner 34. Until it passes through the intermediate transfer belt 21. When a plurality of color toner images are also formed on the secondary transfer roll 30, the intermediate transfer belt 21 does not move until the toner image before the final color passes the portion facing the secondary transfer roll 30. It is designed to be separated.
[0021]
Further, immediately after the belt cleaner 34, a static eliminator 36 is disposed at a position facing the idler roll 28a with the intermediate transfer belt 21 interposed therebetween. The static eliminator 36 has a red LED array arranged in parallel in a direction (width direction) orthogonal to the transport direction of the intermediate transfer belt 21.
A mark MK for position detection is formed on the surface of the intermediate transfer belt 21, and a belt position detection sensor SN for detecting the mark MK is attached downstream of the static eliminator 36. In the image forming apparatus 1, the timing of writing a latent image on the photosensitive drum 16 is controlled by a highly accurate position detection signal of the intermediate transfer belt 21 output from the belt position detection sensor SN.
[0022]
Further, the paper transport system includes a paper tray 41 on which the paper S is placed, a pickup roll 42 for taking out the paper S placed on the paper tray 41, and a separating roll 43 for separating the taken out papers S one by one. A registration roll 44 for temporarily damping the sheet S to adjust the timing, a guide transport path 45 for guiding the sheet S to the secondary transfer device T2, a guide 46 for guiding the sheet S after the secondary transfer, and a sheet And a transport belt 47. Further, a fixing device 48 having a pair of fixing members and fixing the toner transferred to the sheet S by heating and pressure is provided downstream of the sheet conveying belt 47 in the sheet conveying direction. On the downstream side of the fixing device 48 in the sheet conveying direction, a discharge roll 49 for discharging the sheet S after fixing to the outside of the image forming apparatus 1 and a discharge tray 50 for depositing the sheet S discharged outside are provided. ing.
[0023]
In this embodiment, the irradiation position of the laser beam L on the photosensitive drum 16 is the latent image writing position Q1, the area where the photosensitive drum 16 and the rotary developing device 18 are opposed is the developing area Q2, and the photosensitive drum 16 and the intermediate transfer A region facing the belt 21 is a primary transfer region Q3, a region facing the secondary transfer roll 30 and the intermediate transfer belt 21 is a secondary transfer region Q4, and a region facing the neutralizer 36 and the intermediate transfer belt 21 is a neutralizing region Q5. The nip region between the pair of fixing members in the fixing device 48 will be referred to as a fixing region Q6.
[0024]
Next, an image forming operation by the image forming apparatus 1 according to the present embodiment will be described.
When a copy start key of the user interface UI is turned on, a predetermined image forming process is executed. First, a document placed on the platen glass 2 is irradiated by the light source of the document illumination unit 3. The document reflected light reflected from the document is reflected by the first reflection mirror 5 of the document illumination unit 3 and the second reflection mirror 7 and the third reflection mirror 8 of the mirror unit 6, passes through the imaging lens 9, and is picked up by the imaging unit CCD. Read as R, G, B analog signals. The read image signal of the imaging unit CCD is input to the image processing unit IPS. The laser drive signal output device 14 sends out a laser drive signal in accordance with the write image data output from the image processing unit IPS, and the laser beam L is sent from the optical scanning device ROS to the latent image The light is irradiated to the insertion position Q1.
[0025]
The photoconductor drum 16 is driven to rotate in the direction of arrow A, and the surface thereof is charged to a predetermined negative potential by the charger 17. Thus, the latent image is written on the surface of the photosensitive drum 16 at the latent image writing position Q1 by the laser beam L described above. At this time, if the electrostatic latent image written on the photosensitive drum 16 corresponds to the yellow image information, the electrostatic latent image is a yellow developing device that contains the yellow toner T in the developing area Q2. The image is developed at 18Y, and a yellow toner image is formed on the photosensitive drum 16. The toner image formed on the photosensitive drum 16 is transferred to the primary transfer roll T1 by a primary transfer bias applied to the primary transfer roll T1 in a primary transfer area Q3 where the photosensitive drum 16 and the intermediate transfer belt 21 face each other. The image is transferred onto the intermediate transfer belt 21 by the action of a transfer electric field formed between the photosensitive drum 16 and the photosensitive drum 16. On the other hand, the toner T (residual toner) remaining on the intermediate transfer belt 21 after the primary transfer is removed by the drum cleaner 20.
[0026]
When a single-color image (for example, a black-and-white image) is formed, the toner image primarily transferred to the intermediate transfer belt 21 is secondarily transferred to the sheet S immediately. The process of forming the toner image on the body drum 16 and the primary transfer of the toner image are repeated for the number of colors. For example, when a full-color image is formed by superimposing four color toner images, yellow, magenta, cyan, and black toner images are sequentially formed on the photosensitive drum 16, and these toner images are sequentially transferred to the intermediate transfer belt. 21 is primarily transferred. On the other hand, the intermediate transfer belt 21 rotates at the same cycle as the photosensitive drum 16 while holding the yellow toner image first primary-transferred, and is placed at a predetermined position on the intermediate transfer belt 21 every one rotation thereof. , Magenta, cyan and black toner images are superimposed.
[0027]
The toner image primarily transferred onto the intermediate transfer belt 21 in this manner is conveyed to the secondary transfer area Q4 as the intermediate transfer belt 21 rotates. On the other hand, the paper S is taken out of the paper tray 41 by the pickup roll 42, separated by the separation roll 43 one by one, and then transported to the position of the registration roll 44. Thereafter, the sheet S is supplied to the secondary transfer area Q4 so that the toner image on the intermediate transfer belt 21 reaches the secondary transfer area Q4. The transfer roll 30 nips the sheet S. Then, in the secondary transfer area Q <b> 4, the secondary transfer bias applied to the power supply roll 31 causes the transfer electric field formed between the secondary transfer roll 30 and the backup roll 29 to act on the intermediate transfer belt 21. The transferred toner image is secondarily transferred (collectively transferred) to the sheet S. Thereafter, the sheet S to which the toner image has been transferred is conveyed to a fixing device 48 by a guide 46 and a sheet conveying belt 47 to heat and pressurize and fix the toner image on the sheet S, and then discharged to a sheet discharge tray 50. You. On the other hand, the toner (residual toner) attached to the intermediate transfer belt 21 after the secondary transfer is removed by the belt cleaner 34, and thereafter the intermediate transfer belt 21 is discharged by the discharger 36.
[0028]
Next, the fixing device 48 will be described in detail. FIG. 2 is a diagram illustrating a main part of the fixing device 48. The fixing device 48 includes a rotatable heating roll (heating member) 60, and a pressing belt (pressing member) 70 that is in pressure contact with the heating roll 60 and rolls with the heating roll 60. In the present embodiment, the load applied between the heating roll 60 and the pressure belt 70 is set to about 20 to 50 kg. When the fixing device 48 is configured by arranging the heating roll 60 and the pressure roll under pressure, the load applied between the heating roll 60 and the pressure roll is set to about 10 to 150 kg.
The heating roll 60 covers the outer peripheral surface of a metal cylindrical core 61 having good thermal conductivity with an elastic layer 62 made of silicon rubber, and coats the outer peripheral surface of the elastic layer 62 with a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer ( A surface release layer (not shown) made of PFA) resin is formed therein, and a halogen lamp 63 as a heating source is provided therein. The halogen lamp 63 is not limited to the type incorporated in the heating roll 60, but may be an externally arranged one. Further, it goes without saying that a heating source other than the halogen lamp 63 may be used.
[0029]
On the other hand, the pressure belt 70 has a surface made of a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA) resin on an upper part (a side facing the heating roll 60) of a base layer (not shown) made of a heat-resistant polyimide. This is one in which a release layer (not shown) is formed.
[0030]
The support structure of the pressure belt 70 does not have a tension roll or the like, and a first pressure pad 71 made of a heat-resistant elastic material such as silicon rubber is provided inside the pressure belt 70 facing the heating roll 60. A second pressure pad 77 made of a rigid metal or resin is provided, and the pressure belt 70 is attached to the heating roll 60 by the first pressure pad 71 and the second pressure pad 77. By pressing, a fixing region Q6 is formed between the two. That is, the first pressing pad 71 and the second pressing pad 77 constitute a pressing member. Then, by passing the paper S on which the toner T is transferred to the fixing area Q6, the toner T is heated and pressed and fixed.
[0031]
The pressure pad 71 has a tapered top surface that is in a substantially equal pressure state with respect to the fixing region Q6 formed between the pressure pad 71 and the heating roll 60. The pressure pad 71 is disposed so as to fit into a holding member 72 having a concave cross section. The holding member 72 is supported by a support member 74 provided below the spring 73 that urges the pressure pad 71 toward the heating roll 60. The support member 74 has a substantially U-shaped cross section. Attached to the support frame 75. The pressure pad 77 is also attached to the support frame 75. Further, a belt traveling guide 76 having a substantially arc-shaped cross section is attached to the outside of the support frame 75.
[0032]
3 is a perspective view showing an external configuration of the fixing device 48, FIG. 4 is a cross-sectional view of the inside of the fixing device 48 as viewed from the side, and FIG. 5 is a cross-sectional view of the inside of the fixing device 48 as viewed from the rear. . The fixing device 48 has a case 80 that houses the heating roll 60 and the pressure belt 70 (not shown in FIG. 3).
[0033]
A lever 81 is provided on one side of the case 80 so as to be swingable about a shaft (swing center) 81a. An eccentric cam 82 is fixed to the shaft 81a of the lever 81. Below the eccentric cam 82, a frame 83 that can swing around a rotation shaft 83a is provided. A support frame 75 (see FIG. 2) for the pressure belt 70 is attached to the frame 83. On the free end side of the frame 83, a bolt 84 fixed to an apparatus main body (not shown) is erected, and is loosely fitted into a hole provided in the frame 83. Therefore, the frame 83 can basically move freely with respect to the bolt 84. A spring 85 wound around the bolt 84 is attached between the frame 83 and the bolt 84 so as to urge the frame 83 upward against the force received from the eccentric cam 82. ing. The lever 81, the shaft 81a, the eccentric cam 82, the frame 83, the bolt 84, and the spring 85 constitute a (pressing force) adjusting mechanism.
[0034]
That is, when the lever 81 swings in the direction A in the figure, the eccentric cam 82 swings, and the frame 83 swings in the direction B in the figure according to the profile of the eccentric cam 82. The applied pressure belt 70 is separated from the heating roll 60. Further, when the lever 81 once swinged is swung in the direction opposite to the direction A, the frame 83 is swung in the direction C in the drawing by the urging force of the spring 85 as the eccentric cam 82 swings in the opposite direction. Then, the pressure belt 70 attached to the frame 83 comes into pressure contact with the heating roll 60. In the present embodiment, the heating roll 60 and the pressure belt 70 are completely separated from each other by operating the lever 81. However, the present invention is not limited to this, and the pressing force may be reduced.
[0035]
A knob 90 is attached to the inside of the lever 81 so as to be rotatable on the same axis as the shaft 81a (center of rotation). A gear 91 is formed integrally with the knob 90 on the side of the knob 90. I have. Here, the knob 90 and the gear 91 have a hollow portion having a larger diameter than the shaft 81a, and the shaft 81a is disposed so as to penetrate this hollow portion. By employing such a configuration, the swing of the lever 81 and the rotation of the knob 90 can be performed completely independently. A gear 92 meshing with the gear 91 is provided below the gear 91, and a gear 93 integrally formed with the gear 92 is attached to a side of the gear 92. Further, a gear 94 meshing with the gear 93 and a gear 95 meshing with the gear 94 are attached, and the gear 95 meshes with a gear 96 fixed coaxially with the heating roll 60. The knob 90 and the gears 91 to 96 constitute a mechanism for manually driving the heating roll 60.
That is, when the knob 90 is rotated, the driving force is transmitted to the heating roll 60 via the gears 91 to 96.
[0036]
A cover (fixed cover) 86 that covers the lower half of the knob 90 is formed in the case 80. The end 86a of the cover 86 serves as a stopper for the lever 81. On the other hand, a semicircular cover member (moving cover) 87 that covers most of the upper half of the knob 90 with the lever 81 standing is attached to the lever 81.
[0037]
Thus, in the present embodiment, in a state where the lever 81 shown in FIG. 3 is raised, that is, in a state where the heating roll 60 and the pressing belt 70 are pressed against each other, most of the upper part of the knob 90 is covered with the cover member 87. Therefore, it is difficult for the user to rotate the knob 90. On the other hand, in a state where the lever 81 shown in FIG. 6 is laid down (a state in which the lever is swung 90 °), that is, in a state where the heating roller 60 and the pressing belt 70 are separated from each other, the pressure contact between the heating roller 60 and the pressing belt 70 is Since the knob 90 is released and the upper portion of the knob 90 is not covered with the cover member 87, the user can easily turn the knob 90 with a small force. The state where most of the upper portion of the knob 90 is covered with the cover member 87 refers to a state where the user can touch the knob 90 but cannot rotate the knob 90. In other words, even if the knob 90 can be seen from a little outside, if the knob 90 cannot be operated, it is substantially included in the state covered by the cover member 87. The allowable swing range of the lever is not limited to 90 °, but may be larger or smaller, provided that the user can switch between operable and non-operable states. Good.
[0038]
In this embodiment, when a paper jam occurs in the fixing device 48, the lever 81 is first released to release the pressure contact between the heating roll 60 and the pressure belt 70, and then the knob 90 is operated to release the paper. The work must be performed in the order of removing the jammed sheet S. Therefore, a user's erroneous operation does not occur, and damage to the drive transmission system (for example, gears 91 to 96) caused by rotating the knob 90 while keeping the heating roller 60 and the pressure belt 70 pressed against each other is prevented. be able to.
In this embodiment, since the lever 81 and the knob 90 are provided coaxially, the fixing device 48 can be made compact.
[0039]
In the present embodiment, the fixing device 48 has been described as an example, but the present invention is not limited to this. For example, the registration roll 44, the secondary transfer device T2, and the discharge roll used in the image forming apparatus 1 The same can be applied to a transport roll pair (a pair of transport members) such as 49.
[0040]
-Embodiment 2-
This embodiment is substantially the same as the first embodiment, but differs in the configuration and operation of the lever 81 and the knob 90 as shown in FIG. In this embodiment, detailed description of the same components as those in Embodiment 1 will be omitted.
FIG. 7A shows the lever 81 and the knob 90 in a state where the heating roller 60 and the pressure belt 70 are pressed against each other. In the present embodiment, the lever 81 is formed so as to project from the outer peripheral surface of the hollow cover 88, and in this state, the cover 88 completely covers the outer periphery of the knob 90. FIG. 7B shows the lever 81 and the knob 90 in a state where the heating roller 60 and the pressing belt 70 are separated by swinging the lever 81. In the present embodiment, the lever 81 and the cover 88 cannot be pushed into the case 80 when the lever 81 shown in FIG. When the lever 81 shown in FIG. 7B is laid down, the lever 81 and the cover 88 can be pushed into the case 80, and in this state, the knob 90 is exposed to the outside. I have. That is, the relative position of the cover 88 and the knob 90 as viewed from the axial direction can be changed depending on the position of the lever 81.
[0041]
Therefore, also in the present embodiment, if a paper jam occurs in the fixing device 48, the lever 81 is first operated to release the pressure contact between the heating roll 60 and the pressure belt 70, and then the knob 90 is operated. Then, the work must be performed in the order of removing the paper S having the paper jam. Therefore, a user's erroneous operation does not occur, and damage to the drive transmission system (for example, gears 91 to 96) caused by rotating the knob 90 while keeping the heating roller 60 and the pressure belt 70 pressed against each other is prevented. be able to.
Also in this embodiment, since the lever 81 and the knob 90 are provided coaxially, the fixing device 48 can be made compact.
[0042]
In the present embodiment, the user pushes the lever 81 into the case 80. However, the present invention is not limited to this, and the lever 81 and the cover 88 are automatically moved with the swing of the lever 81. You may comprise so that it may be screwed in the case 80 side.
[0043]
Further, in the present embodiment, the type in which the knob 90 is exposed by pushing the lever 81 and the cover 88 toward the case 80 has been described. However, the present invention is not limited to this. For example, FIG. As shown in FIG. 7C, the knob 90 may be protruded from the case 80 side as the lever 81 is swung to expose the knob 90 to the outside.
[0044]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent the device from being damaged due to a user's erroneous operation.
Further, according to the present invention, the size of the device can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an overall configuration of an image forming apparatus according to a first embodiment.
FIG. 2 is a diagram illustrating a main part of a fixing device.
FIG. 3 is a perspective view illustrating an external configuration of the fixing device.
FIG. 4 is a cross-sectional view of the inside of the fixing device as viewed from a side.
FIG. 5 is a cross-sectional view of the inside of the fixing device as viewed from the rear.
FIG. 6 is a diagram illustrating operations of a lever and a knob.
FIG. 7 is a diagram illustrating a configuration of a lever and a knob according to a second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 16 ... Photoreceptor drum, 18 ... Rotary developing device, 21 ... Intermediate transfer belt, 29 ... Backup roll, 30 ... Secondary transfer roll, 48 ... Fixing device, 60 ... Heating roll, 63 ... Halogen lamp , 70 ... Pressing belt, 71 ... Pressing pad, 72 ... Holding member, 73 ... Spring, 74 ... Support member, 75 ... Support frame, 80 ... Case, 81 ... Lever, 81a ... Shaft, 82 ... Eccentric cam, 83 ... Frame, 83a ... Rotating shaft, 84 ... Bolt, 85 ... Spring, 86 ... Cover part, 87 ... Cover member, 90 ... Knob, 91-96 ... Gear, Q1 ... Latent image writing position, Q2 ... Development area, Q3: primary transfer area, Q4: secondary transfer area, Q5: static elimination area, Q6: fixing area, S: paper, T1: primary transfer device (primary transfer roll), T2: secondary transfer device

Claims (15)

Conveying means for nip conveying the sheet using a pair of conveying members arranged in pressure contact,
Pressing force applying means for applying a pressing force to the conveying means,
Pressing force changing means for manually weakening or canceling the pressing force by the pressing force applying means,
And a manual drive unit configured to be operable after performing an operation on the pressing force changing unit and manually driving the transport unit. The pressing force changing means has a lever that is swingably disposed,
2. The sheet conveying apparatus according to claim 1, wherein the manual driving unit has a knob rotatably disposed. 3. The sheet conveying apparatus according to claim 2, wherein the center of rotation of the lever and the center of rotation of the knob are the same. A transport member rotatably disposed;
An opposing conveying member rotatably pressed against the conveying member,
An adjusting member that adjusts a pressing force acting between the transport member and the opposing transport member,
A driving member for manually driving the transport member,
The driving member is exposed in an operable state in conjunction with the operation of weakening or releasing the pressing force by the adjusting member, and the driving is performed in conjunction with the operation of increasing or applying the pressing force by the adjusting member. And a cover member for covering the operation member in an inoperable state. The driving member is rotatably arranged, and the adjusting member is swingably arranged,
The sheet conveying device according to claim 4, wherein a rotation center of the driving member and a swing center of the adjustment member are the same. 6. The sheet conveying apparatus according to claim 5, wherein the cover member is swingably disposed about the swing center. The cover member,
A fixed cover that is fixedly arranged and constantly covers a part of the driving member;
5. The sheet conveying apparatus according to claim 4, further comprising a movable cover formed integrally with the adjusting member and exposing or covering the driving member in conjunction with the operation of the adjusting member. The sheet conveying device according to claim 4, wherein a relative position of the driving member and the cover member changes in an axial direction in conjunction with an operation of the adjustment member. Conveying means for nip conveying the sheet using a pair of conveying members arranged in pressure contact,
Pressing force adjusting means for adjusting the pressing force of the pair of conveying members,
Having manual driving means for manually driving the transport means,
The sheet conveying device according to claim 1, wherein the manual driving unit can be accessed when the pressing force is reduced or released by the pressing force adjusting unit. 10. The sheet conveying apparatus according to claim 9, wherein the manual driving unit is not accessible when the pressing force is increased or added by the pressing force adjusting unit. A heating member having a heating source and rotatably disposed,
A pressure member rotatably pressed against the heating member, and a recording medium holding an unfixed toner image held between the heating member and the pressure member;
A pressing force adjusting mechanism for adjusting a pressing force acting between the heating member and the pressing member,
A manual drive mechanism for manually driving the heating member or the pressure member,
In conjunction with the operation of weakening or releasing the pressing force by the pressing force adjusting mechanism, the manual driving mechanism is exposed in an operable state, and the operation of increasing or adding the pressing force by the pressing force adjusting mechanism. A cover for interlockingly covering the manual drive mechanism in an inoperable state. 12. The pressure member according to claim 11, wherein the pressure member comprises an endless pressure belt, and a pressure member for pressing the pressure belt toward the heating member is provided inside the pressure belt. The fixing device as described in the above. The pressing force adjusting mechanism has a lever for moving the pressing member,
The manual drive mechanism has a knob for rotating the heating member,
The fixing device according to claim 11, wherein the lever and the knob are disposed so as to rotate about the same axis. The cover,
A fixed cover that is fixedly arranged and constantly covers a part of the knob;
14. The fixing device according to claim 13, further comprising a movable cover formed integrally with the lever and exposing or covering the knob in conjunction with the operation of the lever. 14. The fixing device according to claim 13, wherein a relative position of the knob and the cover changes in an axial direction in conjunction with an operation of the lever.

Images