JP2009151133A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To address both the release of the pressure contact in removing a paper jam and the release of the pressure contact when not in use for a long period of time with a simple configuration. <P>SOLUTION: A fixing device includes a heating roller 210 supported by a heating frame 230, a pressure roller 220 supported by a rotatable pressure frame 240, and a pressure contact release device for releasing the pressure contact between the pressure roller 220 and the heating roller 210 by moving the pressure frame 240. The pressure release device creates a first pressure contact release state in which the space between the pressure roller and the heating roller is made to be a predetermined value by driving a driving member 250 for moving the pressure frame 240, and a second pressure contact release state in which the distance between the pressure roller 220 and the heating roller 210 is made to be a predetermined value by driving the driving member on the pathway different from the pathway in the first pressure contact release state for moving the pressure frame 240. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention includes a heating roller that heats a transfer material carrying a toner image, and a pressure roller that presses the transfer material against the heating roller, the heating roller being held by a heating roller support member, The roller is held by a pressure roller support member pivotally supported at the lowermost part, and the gap between the heating roller and the pressure roller is variably arranged, and the pressure roller support member is moved. The present invention relates to a fixing device including a pressure contact release device that releases pressure contact between the pressure roller and the heating roller, and an image forming apparatus including the same.

  In the conventional fixing device configuration, each roller has an elastic layer in order to give heat to the transfer paper sufficient to fix the toner to the transfer paper, and a nip is formed by the deformation, so that the required heating time is reduced. Secured. A larger amount of deformation may be required depending on the toner used, the transfer paper conveyance linear velocity, and the like.

  In addition, each roller is held in a state where the elastic layer is deformed when the main body device is operated, so that a jam that occurs when the transfer paper passes between the heating roller and the pressure roller is to be removed. This is achieved by providing a pressure release device for the heating roller of the pressure roller.

  Regarding the deformation of the elastic layer, for example, when the apparatus main body is not used for a long period of time, the outer diameter shape of each deformed roller may not return, and as a result, abnormal noise is generated when the fixing unit is driven, and abnormal images are generated. It becomes.

  Japanese Patent Application Laid-Open No. 2004-133867 discloses a fixing device of an image forming apparatus that includes a release device that releases pressure applied by a pressure unit that presses the transfer material against a heating unit that heats a transfer material carrying a toner image. That is, when the paper is removed, the one end of the release device that releases the pressurization of the pressurizing means is used as a fulcrum. The swinging member provided with a projecting portion protruding from a part of the swinging member constituting the returning means for returning to the position is constituted by a lever member engaged with one end of the swinging cover member, and at different positions. It is described that two cams projecting to the pressurizing means side are provided, one cam constituting the releasing device and the other cam constituting the returning means.

  Patent Document 2 includes an urging mechanism that presses and presses the pressure roller against the fixing roller. The back packing body for the printer includes a fixing unit pressure canceling device. In the process, the release lever contacts the printer, the slide member moves in the direction of engagement with the second urging lever of the urging mechanism, and the first urging lever is pulled down via the second urging lever. In addition to releasing the pressure contact between the fixing roller and the pressure roller, the engagement with the second urging lever is released in the process of unpacking, and the pressure roller is pressed against the fixing roller. Yes.

Patent Document 3 discloses a fixing device that feeds a recording medium carrying an image between a heating member and a pressure member and fixes the image on the recording medium, and press-contacts the heating member and the pressure member. Contact / separation adjusting means for canceling and releasing the contact, and the contact / separation adjusting means cancels the pressure contact between the heating member and the pressure member when a job signal related to image formation is not input to the image forming apparatus main body. Things are listed.
2003-186340 2007-163914 2005-201917 publication

  Conventionally, the above-mentioned problems can be dealt with by separately providing a pressure release structure for preventing deformation of the outer diameter of each roller when the apparatus main body is not used for a long time, separately from the pressure release structure for removing the jam. ing.

  However, if a separate pressure release mechanism used when the apparatus main body is not used is separately provided, there is a problem that the configuration of the fixing apparatus becomes complicated and the cost increases.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device and an image forming apparatus that can cope with both pressure release during jam removal and pressure release when not used for a long time with a simple configuration.

  The invention of claim 1 includes a heating roller that heats a transfer material carrying a toner image, and a pressure roller that presses the transfer material against the heating roller, and the heating roller is held by a heating roller support member, The pressure roller is held by a pressure roller support member pivotally supported at the lowermost part thereof, and the gap between the heating roller and the pressure roller is variably arranged. In a fixing device including a pressure release device that moves and releases the pressure contact between the pressure roller and the heating roller, the pressure release device moves the pressure roller support member, and the pressure roller and the heating roller. A first pressure release state in which the interval between the first pressure contact and the first pressure contact unlocking state is driven by moving the pressure roller support member by driving the drive member in a path different from the first pressure contact unlocking state, The pressure b La a fixing device comprising predetermined to be a second pressure canceled state the distance between the heating roller.

  According to a second aspect of the present invention, in the fixing device according to the first aspect, in the first press-contact release state, the driving member is rotated while the tip thereof is in contact with the heating roller support member, and the pressurization is performed. A roller support member is rotated to change the dimension between the heating roller and the pressure roller, and a spacer member is inserted between the drive member and the heating roller support member in the second pressure released state. The pressure roller support member is moved in parallel to change the dimension between the heating roller and the pressure roller.

  The invention of claim 3 comprises a heating roller for heating a transfer material carrying a toner image, and a pressure roller for pressing the transfer material against the heating roller, the heating roller being held by a heating roller support member, The pressure roller is held by a pressure roller support member pivotally supported at the lowermost part thereof, and the gap between the heating roller and the pressure roller is variably arranged. In a fixing device including a pressure contact release device that moves and releases the pressure contact between the pressure roller and the heating roller, the heating roller is held by a heating roller support member, and the pressure roller is rotatable at its lowermost portion. Is held by a pressure roller support member supported by a shaft, and a space between the heating roller and the pressure roller is variably arranged, and the pressure release device is located above the rotation axis of the pressure roller. And a driving member that changes the distance between the pressure roller and the heating roller in contact with the heating roller support member that supports the heating roller. A first pressure contact release state in which the pressure roller support member is moved and the distance between the pressure roller and the heating roller is set to a predetermined first value, and the first pressure contact A second angle that is rotated by a larger angle than the released state, moves with the pressure roller support member, and sets the distance between the pressure roller and the heating roller to a second value that is larger than the first value. It is a fixing device that is driven to a pressure release state.

  According to a fourth aspect of the present invention, in the fixing device according to the third aspect, an operating portion is disposed on the driving member, and the operating portion is disposed at a position protruding from the fixing device main body when the driving member is in the second position. It is characterized by that.

  According to a fifth aspect of the present invention, in the fixing device according to the third or fourth aspect, the drive member is always urged in a direction to move to the second position, and the operation portion is always related to the exterior cover member. The driving member is stopped and held in the first position, and the operating portion moves to the second position when the exterior cover member is removed. The operation is characterized by interlocking with the apparatus outer cover.

  According to a sixth aspect of the present invention, in the fixing device according to any one of the third to fifth aspects, a detection device that detects an arrangement position of the driving member is provided.

  According to a seventh aspect of the present invention, in the fixing device according to the sixth aspect, the detection device detects a paper transport jam state.

  According to an eighth aspect of the present invention, in the fixing device according to any one of the first to seventh aspects, a moving amount of the driving member for obtaining the first value is larger than a moving amount for obtaining the second value. It is characterized by.

  A ninth aspect of the invention is an image forming apparatus comprising the fixing device according to any one of the first to ninth aspects.

  According to the fixing device and the image forming apparatus of the present invention, the pressure release at the time of jam removal and the pressure release when not used for a long time can be performed by one mechanism, so both can be handled by a simple mechanism. There is an effect that an increase in cost can be suppressed.

  Embodiments as the best mode for carrying out the present invention will be described below with reference to the drawings.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view illustrating an image forming apparatus according to an embodiment. The image forming apparatus 100 is a color printer that superimposes and transfers yellow (Y), magenta (M), cyan (C), and black (K) toner images on transfer paper. The image forming apparatus 100 includes an image forming unit 110 including development units 110Y, 110C, 110M, and 110K for each color, an exposure unit 120, a transfer unit 130, a transfer paper storage unit 140 that stores transfer paper, and a paper feed unit. 150 and a fixing device 200. In this example, the image forming apparatus 100 includes a document reading device 160.

  Based on the image signal from the current reading device 160 or the host device, the laser beam from the exposure unit 120 is irradiated to the image carrier of the developing units 110Y, 110C, 110M, and 110K, and the latent image formed on the image carrier is a toner. The toner images of the respective colors are formed on the image carriers of the 110 developing units 110Y, 110C, 110M, and 110K. The increase in toner of each color is transferred to the intermediate transfer belt of the transfer unit 130.

  The transfer paper stored in the transfer paper storage unit 140 is sent to the transfer unit 130 by the paper supply unit 150, and after the toner image is transferred by the transfer unit 130, the fixing device 200 uses the heating roller 210 and the pressure roller 220. The toner image is fixed on the transfer paper and is discharged to the paper discharge tray by the transport roller.

  Next, the fixing device 200 will be described. 2A and 2B show a basic configuration of the fixing device according to the first embodiment. FIG. 2A is a side view, FIG. 2B is a plan view, and FIG. 3 shows an operation of the fixing device during jam removal. 4 is a side view of the fixing device, FIG. 4 shows the operation of the fixing device when the device is not used, (a) is a side view, and (b) is a plan view.

  In the fixing device 200, the heating roller 210 is pivotally supported by the heating frame 230, and the pressure roller 220 is pivotally supported by the pressure frame 240. In the heating frame 230, a stepped portion 231 having a concave portion 231a and a convex portion 231b is disposed.

  In the fixing device 200, a pressure release device is disposed between the heating frame 230 and the pressure frame 240, and the heating roller 210 and the pressure roller 220 in the pressure contact state are driven to two pressure release states. . One press release state is a first press release state for removing jam that releases the press contact between the heating roller 210 and the pressure roller 220 when the transfer paper is in a jam state, and is separated by a predetermined interval. It is. The other pressure release state is a second pressure release state for releasing the pressure contact between the heating roller 210 and the pressure roller 220 when the image forming apparatus is not used for a long time.

  The pressure frame 240 is configured to be swingable about the shaft portion 241. In addition, a driving member 250 rotatably supported on a shaft 251 is disposed on the pressure frame 240, and a contact piece 252 that contacts the heating frame 230 is disposed on the lower end of 250.

  Here, the contact piece 252 is slidably disposed on the shaft 251 at the base 253, and the contact piece 252 is selected along the recess 231 a and the protrusion 231 b of the step portion 231 by moving along the shaft 251. Can be contacted. In this example, when the heating roller 210 and the pressure roller 220 are separated from each other, the contact piece 252 is brought into contact with 231a at the time of jam removal, and the contact piece 252 is brought into contact with the convex portion 231b when the apparatus is not used. .

  That is, when a jam occurs in the recording paper, as shown in FIG. 3, the drive member 250 is rotated while the contact piece 252 is in contact with the heating frame 230, so that the first pressure release state is established. Thereby, the heating roller 210 and the pressure roller 220 can be separated by a dimension A. 3 indicates an exterior cover of the image forming apparatus 100.

  When the apparatus is not used, as shown in FIG. 4, the contact piece 252 is moved along the shaft 251 (arrow B), and the contact piece 252 is brought into contact with the convex portion 231 b of the step portion 231. As a result, the second pressure release state in which the heating roller 210 and the pressure roller 220 are separated from each other by the dimension C can be obtained.

  In this example, the amount of movement of the drive member 250 that moves the pressure roller 220 is the same when the dimension A is the same as the dimension B, when jam is removed (FIG. 3), and when the apparatus is not used (FIG. 4). ) Is at least better. This is because when the jam is removed, the heating roller 210 and the pressure roller 220 are heated, and the dimensions are large, so the heating roller 210 and the pressure roller 220 are in a cooled state when the apparatus is not used. This is because it needs to be moved more greatly. Note that the amount of movement of the drive member 250 and the values of the dimension A and the dimension B can be changed as needed.

  Therefore, according to the fixing device 200 according to the present example, the driving member 250 can be turned to the first pressure released state when the jam is removed, and the contact piece 252 is slid when not used for a long time. It can be set as the 2nd press-contact cancellation | release state. For this reason, since press-contact cancellation | release in both cases can be performed with one mechanism, the raise of cost can be suppressed.

  Next, a second embodiment will be described. Hereinafter, the same members as those in the first embodiment will be described with the same reference numerals. 5 and 6 are side views showing the fixing device according to the second embodiment, and FIG. 7 is an enlarged view of a contact piece of the fixing device shown in FIG. In the fixing device 300 according to this example, a driving member 320 that can rotate about a shaft 310 is disposed on the pressure frame 240. A contact piece 330 that contacts the heating frame 230 is disposed at one end of the driving member 320. In this example, the heating frame 230 is not provided with a stepped portion, and the contact piece 330 contacts the flat end 231 of the heating frame 230.

  Further, in this example, as shown in FIG. 7, the contact piece 330 is formed with flat contact portions 331 and 332 at two locations so that the heating frame 230 comes into contact with the heating frame 230 in a stable state and is heated. The positions of the roller 210 and the pressure roller 220 can be stably held.

  The drive member 320 is moved to a position D in FIG. 5 in a state where the exterior cover 260 of the image forming apparatus is disposed, that is, inside the image forming apparatus 100, and between the heating roller 210 and the pressure roller 220. A gap of size F is formed in On the other hand, when the jam is resolved, the outer cover 260 is removed and moved to a position E in FIG. A gap having a dimension G is formed between the heating roller 210 and the pressure roller 220.

  That is, when the apparatus is not used, the driving member 320 can release the second pressure contact state by separating the heating roller 210 and the pressure roller 220 with the exterior cover 260 attached. In a state where the outer cover 260 is removed and the image forming apparatus 100 cannot be used, the heating roller 210 and the pressure roller 220 are separated from each other to be in a first pressure contact release state.

  Therefore, according to this embodiment, the fixing device can be made simple and inexpensive, and at the end of the jam removal operation, the exterior cover cannot be attached and the image forming apparatus cannot be operated. When the image forming apparatus is not used for a long period of time, it is possible to store the heating roller and the pressure roller separately with the main body outer cover closed.

  Next, a third embodiment will be described. This example is a modification of the second embodiment. 8 and 9 are side views showing the fixing device according to the third embodiment. In the fixing device 400 according to this example, the shaft 310 and the pin 411 disposed on the pressure frame 240 and the pin 412 disposed on the drive member 320 are locked between the pressure frame 240 and the drive member 250. The torsion coil spring 410 that normally biases the drive member 320 in the direction in which the contact piece 330 presses the heating frame 230 is disposed. Note that a handle 340 is disposed on the driving member 320 to facilitate operation from above.

  In addition, the exterior cover 260 is in contact with the drive member 320 with the exterior cover 260 attached, and resists the biasing force of the coil spring 410 so that the drive member 320 is heated with the heating roller 210, the pressure roller 220, and the like. A convex portion 420 is disposed to hold at a position where the pressure contacts.

  In this example, with the above configuration, the operation of removing the outer cover 260 and the operation of separating the heating roller 210 and the pressure roller 220 are linked.

  Next, a fourth embodiment will be described. This example is a modification of the second embodiment. FIG. 10 is a side view showing the fixing device according to the fourth embodiment. In this example, the photo interrupter 510 detects the shielding plate 520 disposed on the driving member 320 to detect whether the driving member 320 is at the pressing position of the pressure roller or at the pressing release position. . According to this example, when the shielding plate 520 is not detected by the photo interrupter 510, it can be determined that the heating roller 210 and the pressure roller 220 are in a separated state, and the operation of the image forming apparatus 100 is prohibited, and the heating roller Printing in the separated state between 210 and the pressure roller 220 can be prevented.

  Therefore, according to this embodiment, when the image forming apparatus 100 is not used for a long period of time and is in a use start state, or after the jam is cleared, forgetting to operate the press contact release device to the apparatus main body operating position. It is possible to prevent problems such as jamming and fixing failure.

  Next, a fifth embodiment will be described. This example is a modification of the fourth embodiment. 11A and 11B show a fixing device according to a fifth embodiment. FIG. 11A is a side view and FIG. 11B is a front view. In the fixing device 500 according to the present example, a photo interrupter 610 is disposed, and detects a jammed state in addition to detecting the pressure contact release state of the heating roller 210 and the pressure roller 220. That is, the arm member 321 and the shielding plate 322 are disposed on the driving member 320, and the optical path of the photo interrupter 610 is blocked when the pressure contact between the heating roller 210 and the pressure roller 220 is released, and the jam detection device 620 is shielded. A plate 621 is provided, and the shielding plate 621 puts the photo interrupter 610 into a shielding state when a jam occurs.

  Therefore, according to the present embodiment, it is possible to detect a jam without adding a new component, and it is not necessary to reduce the number of components and secure a space for component placement.

1 is a schematic cross-sectional view illustrating an image forming apparatus according to an embodiment. 1 illustrates a basic configuration of a fixing device according to a first embodiment, where (a) is a side view and (b) is a plan view. FIG. 3 is a side view showing the operation of the fixing device when the jam of the fixing device shown in FIG. 2 is removed. FIG. 2 illustrates an operation of the fixing device when the apparatus is not used, (a) is a side view, and (b) is a plan view. FIG. 6 is a side view showing a fixing device according to a second embodiment. FIG. 6 is a side view showing a fixing device according to a second embodiment. FIG. 6 is an enlarged view of a contact piece of the fixing device illustrated in FIG. 5. FIG. 10 is a side view showing a fixing device according to a third embodiment. FIG. 10 is a side view showing a fixing device according to a third embodiment. FIG. 10 is a side view illustrating a fixing device according to a fourth embodiment. FIG. 10 is a side view illustrating a fixing device according to a fifth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 110 Image forming part 110Y, 110C, 110M, 110K Developing unit 120 Exposure part 130 Transfer part 140 Transfer paper storage part 150 Paper feed part 160 Document reading apparatus 200 Fixing apparatus 210 Heating roller 220 Pressure roller 230 Heating frame 231 Step 231a Concave 231b Convex 240 Pressure frame 241 Shaft 250 Drive member 251 Shaft 252 Contact piece 253 Base 260 Exterior cover 300 Fixing device 310 Shaft 320 Drive member 321 Arm member 322 Shielding plate 330 Contact pieces 331, 332 Flat part 340 Handle 400 Fixing device 410 Torsion coil spring 411, 412 Pin 420 Protrusion 500 Fixing device 510 Photo interrupter 520 Shield plate 610 Photo interrupter 620 Jam detection device 621 Shield plate

Claims (9)

A heating roller that heats the transfer material carrying the toner image; and a pressure roller that presses the transfer material against the heating roller. The heating roller is held by a heating roller support member, and the pressure roller is The pressure roller is supported by a pressure roller support member that is pivotally supported in the lower part, and the pressure roller is moved by moving the pressure roller support member while the interval between the heat roller and the pressure roller is variable. In a fixing device including a pressure release device that releases pressure contact between the heating roller and the heating roller,
The pressure release device is
A first pressure contact release state in which the pressure roller support member is moved, and a distance between the pressure roller and the heating roller is set to a predetermined first value;
The driving member is driven by a path different from the first pressure contact unlocking state to move the pressure roller support member, and a second pressure contact in which a distance between the pressure roller and the heating roller is determined in advance. A fixing device which is in a released state. In the first pressure contact release state, the driving member is rotated while the tip thereof is in contact with the heating roller support member, and the pressure roller support member is rotated, so that the heating roller and the pressure roller Change the dimension between
In the second pressure released state, a spacer member is inserted between the drive member and the heating roller support member, and the pressure roller support member is moved in parallel between the heating roller and the pressure roller. The fixing device according to claim 1, wherein the dimensions of the fixing device are changed. A heating roller that heats the transfer material carrying the toner image; and a pressure roller that presses the transfer material against the heating roller. The heating roller is held by a heating roller support member, and the pressure roller is The pressure roller is supported by a pressure roller support member that is pivotally supported in the lower part, and the pressure roller is moved by moving the pressure roller support member while the interval between the heat roller and the pressure roller is variable. In a fixing device including a pressure release device that releases pressure contact between the heating roller and the heating roller,
The heating roller is held by a heating roller support member, and the pressure roller is held by a pressure roller support member that is pivotally supported at the lowermost portion thereof, and the interval between the heating roller and the pressure roller can be varied. And placed
The pressure release device is supported so as to be swingable at an upper position different from the rotation axis of the pressure roller, and is in contact with a heating roller support member that supports the heating roller, so that the pressure roller and the heating roller are between A drive member that changes the distance of
The drive member is
A first pressure contact release state that is rotated by a predetermined angle and moves the pressure roller support member to set a predetermined first value as an interval between the pressure roller and the heating roller;
Rotated by a larger angle than the first pressure-release state, moved with the pressure roller support member, and a second value larger than the first value between the pressure roller and the heating roller. The fixing device is driven to a second pressure released state.   The fixing device according to claim 3, wherein an operation unit is disposed on the driving member, and the operation unit is disposed at a position protruding from the fixing device main body when the driving member is in the second position. The drive member is always biased in the direction of moving to the second position,
The operation unit is always locked to an exterior cover member, and the driving member is held in the first position,
The operation unit moves to the second position when the outer cover member is removed, and the operation to the pressure release position is interlocked with the apparatus outer cover. Item 5. The fixing device according to Item 3 or 4.   The fixing device according to claim 3, further comprising a detection device that detects an arrangement position of the driving member.   The fixing device according to claim 6, wherein the detection device detects a paper conveyance jam state.   The fixing device according to claim 1, wherein a moving amount of the driving member for obtaining the first value is larger than a moving amount of the driving member for obtaining the second value. An image forming apparatus comprising the fixing device according to claim 1.