JP2012163821A - Fixing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device and an image forming apparatus that can improve durability of a fixing member, a pressing member and a sliding member and prevent rotation unevenness of the fixing member generated during the movement of the sliding member, wrinkles in transfer paper due to vibration and image disturbance.SOLUTION: A fixing device having: a fixing member; and a pressurizing member for forming a nip part to be opposed to the fixing member, and fixing an unfixed toner image to a recording medium passing through the nip part comprises: a pressing member provided in the fixing member to press the pressurizing member from the inside of the fixing member; a sliding member moving by a prescribed distance between the fixing member and the pressing member; and a clocking means for measuring integration time in which the recording medium passes through the nip part. The prescribed distance in which the sliding member moves is changed corresponding to the integration time.

Description

  The present invention relates to a fixing device and an image forming apparatus.

  2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic method, a belt-type fixing device is used as a fixing device that fixes a toner image transferred onto a recording sheet. A belt-type fixing device includes a rotatable fixing belt having a heating source, a pressure roller that rotates in pressure contact with the fixing belt, and an inner side of the fixing belt, and the fixing belt faces the pressure roller. And a pressing member that forms a nip portion between the fixing belt and the pressure roller, and the transfer paper is passed through the nip portion to fix the unfixed toner image on the transfer paper by heat and pressure. This is known.

  Further, a rotatable fixing roller having a heating source, a pressure belt that presses and rotates against the fixing roller, and is disposed inside the pressure belt, and presses the pressure belt toward the fixing roller. And a pressing member that forms a nip portion between the pressure belt and the fixing roller. By passing the transfer paper through the nip portion, the unfixed toner image on the transfer paper is heated and pressed and fixed. Things are also known.

  FIG. 5A is a cross-sectional view illustrating a configuration of a conventional fixing device 5. The configuration of the fixing belt 51 and the pressure roller 54 will be described with reference to FIG. The fixing belt 51 is disposed on the toner image T carrying surface side of the transfer paper P. A halogen heater 84 is disposed inside the fixing belt 51 as an example of a heat source.

  The pressing member 83 presses the pressure roller 54 via the fixing belt 51 to form a nip portion N. The pressing member 83 is held by a holding member 65. A low friction pressing member 68 is arranged between the inner peripheral surface of the fixing belt 51 and the pressing member 83 in order to reduce sliding resistance between the inner peripheral surface of the fixing belt 51 and the pressing member 83. Conventionally, the pressing member 68 is fixed.

  The pressure roller 54 is disposed so as to face the fixing belt 51, and is configured to rotate in the direction of arrow D by a driving motor (not shown) so that the fixing belt 51 is driven to rotate. The pressure roller 54 is configured by laminating a metal core 541, a heat-resistant elastic body layer 542 coated on the outer peripheral surface of the metal core 541, and a release layer 543 that is further coated with a heat-resistant resin or a heat-resistant rubber. ing.

  The fixing belt 51 is an endless belt whose original shape is formed in a cylindrical shape as shown in FIG. 5B, and is made of heat-resistant resin such as polyimide, polyamide, polyimide amide, SUS (Stainless Used Steel), nickel. And a release layer 512 made of a fluororesin or the like coated on the surface or both surfaces of the base layer 511 on the pressure roller 54 side. A heat-resistant elastic layer 513 is provided between the base layer 511 and the release layer 512 (outermost layer) in some cases.

  By the way, in the belt-type fixing device, when the friction coefficient between the endless belt (fixing belt and pressure belt) and the pressing member is large, the torque for driving the endless belt increases, and the endless belt is driven. The driving torque acting on the fixing roller or the pressure roller is also increased, and the fixing roller or the pressure roller is damaged and the load on the drive gear train is increased. In addition, the load on the drive motor also increases, and more power may be required. Furthermore, the wear of the inside of the endless belt and the sliding portion of the pressing member is severe, and the life of the parts may be significantly shortened.

  When the frictional force between the endless belt and the pressing member becomes so large that it cannot be ignored compared to the driving force of the endless belt by the fixing roller and the pressure roller, slip occurs between the fixing roller and the pressure roller and the endless belt, If the transfer paper holding the unfixed toner image is passed through the nip under these conditions, wrinkles may occur on the transfer paper, or image misalignment may occur on the unfixed toner image on the transfer paper. It was.

  Under such circumstances, these fixing devices are required to have a small sliding resistance between the endless belt and the pressing member disposed inside the endless belt. For this reason, a sliding sliding member is usually provided between the inner side of the endless belt and the pressing member, or oil or grease is applied between the inner side of the endless belt and the pressing member, for example. (For example, patent document 1) is performed.

  However, according to this method, although both sliding resistances can be reduced initially, it cannot be said that durability over time is sufficient. It is generally known that the fixing performance varies depending on the paper type (paper characteristics: for example, paper thickness and paper surface properties). In particular, the effect of the paper thickness is large, and the nip time and fixing set temperature are changed for each paper thickness. In other words, the change in the nip time is set by changing the rotation speed of the fixing member or changing the nip width.

  Although the response by changing the nip width does not affect the print productivity, there is a problem that the sliding resistance of the pressing member increases and the mechanism becomes complicated, resulting in an increase in the size and cost of the apparatus. In addition, the response by changing the rotation speed of the fixing member can reduce the rotation speed of the fixing member, so that the sliding resistance of the pressing member can be reduced, and no special mechanism is required. However, there is a problem that print productivity is lowered.

  Since the pressure in the nip increases as the paper thickness increases, the sliding resistance of the pressing member increases. For this reason, even if the rotation speed of the fixing member can be set low to improve the fixability of the cardboard, it cannot be extended as much as the life of the pressing member is expected. In order to improve the life of the pressing member, it is not sufficient to lower the rotation speed of the fixing member. The life of the pressing member has a large fluctuation range depending on the paper type (particularly, paper thickness) in addition to the rotation speed of the fixing member. It is. That is, the life of the pressing member has a greater effect when the transfer paper passes through the nip than when the paper does not pass through the nip.

  Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to provide a fixing device and an image forming apparatus that can improve the durability of a fixing member, a pressing member, and a sliding member. To do.

  In order to solve the above-described problem, the fixing device according to the first aspect of the present invention includes a fixing member and a pressure member that forms a nip portion facing the fixing member and passes through the nip portion. A fixing device that fixes an unfixed toner image on a recording medium, the fixing device being provided inside the fixing member, pressing the pressure member from the inside of the fixing member, the fixing member, and the pressing A sliding member that moves between the members by a predetermined distance, and a time measuring unit that measures an accumulated time that the recording medium passes through the nip portion, and the predetermined distance that the sliding member moves is It changes according to the integration time.

  According to a second aspect of the present invention, there is provided a fixing device according to the present invention, comprising: a fixing member; and a pressure member that forms a nip portion facing the fixing member, and is not fixed to a recording medium that passes through the nip portion. A fixing device for fixing a toner image, wherein the fixing device is provided inside the fixing member and presses the pressing member from the inside of the fixing member, and between the fixing member and the pressing member. A sliding member that moves, a switching unit that switches the sliding member to a moving state or a stopped state, and a time measuring unit that measures an accumulated time for the recording medium to pass through the nip portion, and the switching unit includes: The sliding member is switched to a moving state or a stopped state corresponding to the accumulated time.

  The fixing device according to the third aspect of the present invention further includes a fixing member and a pressure member that forms a nip portion facing the fixing member, and is not fixed to a recording medium that passes through the nip portion. A fixing device for fixing a toner image, wherein the fixing device is provided inside the fixing member and presses the pressing member from the inside of the fixing member, and between the fixing member and the pressing member. A sliding member that moves, a switching unit that switches the sliding member to a moving state or a stopped state, and a determination unit that determines a type of the recording medium, the switching unit corresponding to the type of the recording medium Then, the sliding member is switched to a moving state or a stopped state.

  According to a fourth aspect of the present invention, there is provided a fixing device according to the present invention, comprising: a fixing member; and a pressure member that forms a nip portion facing the fixing member, and is not fixed to a recording medium that passes through the nip portion. A fixing device for fixing a toner image, wherein the fixing device is provided inside the fixing member and presses the pressing member from the inside of the fixing member, and between the fixing member and the pressing member. A sliding member that moves, a switching unit that switches the sliding member to a moving state or a stopped state, a time measuring unit that measures an accumulated time that the recording medium passes through the nip portion, and a type of the recording medium Discriminating means, and the switching means switches the sliding member to a moving state or a stopped state in accordance with the accumulated time and / or the type of the pre-recording medium.

  According to a fifth aspect of the present invention, there is provided a fixing device according to the present invention, comprising: a fixing member; and a pressure member that forms a nip portion facing the fixing member, and is not fixed to a recording medium that passes through the nip portion. A fixing device for fixing a toner image, wherein the fixing device is provided inside the fixing member and presses the pressing member from the inside of the fixing member, and between the fixing member and the pressing member. A sliding member that moves; a switching unit that switches the sliding member to a moving state or a stopped state; and a detection unit that detects whether or not the recording medium passes through the nip portion. Is characterized in that, when the detection means detects that the recording medium has not passed through the nip portion, the sliding member is switched to a moving state or a stopped state.

  According to another aspect of the fixing device of the present invention, in the fixing device according to any one of claims 1 to 5, the sliding member is provided with a starting end and a terminal end, and the sliding member has a sliding end at the starting end. The supply member for supplying the moving member is provided with a recovery member for recovering the slide member at the end of the slide member, and the slide member is provided between the supply member and the recovery member. It is characterized by moving.

  Further, in order to solve the above problem, an image forming apparatus according to a seventh aspect of the present invention includes the fixing device according to any one of the first to sixth aspects.

  According to the present invention, the durability of the fixing member, the pressing member, and the sliding member is improved, and the rotation unevenness of the fixing member that occurs when the sliding member moves, the transfer paper sheet due to vibration, and the occurrence of image disturbance are prevented. be able to.

2A is a cross-sectional view illustrating a configuration of a fixing device according to an exemplary embodiment of the present invention, and FIG. FIG. 4A is a cross-sectional view showing a configuration of a fixing device in another embodiment of the present invention, and FIG. 5B is a cross-sectional view showing a configuration of a fixing belt. FIG. 6A is a cross-sectional view showing a configuration of a fixing device according to still another embodiment of the present invention, and FIG. 1 is a cross-sectional view illustrating an overall configuration of an image forming apparatus including a fixing device according to an embodiment of the present invention. 2A is a cross-sectional view illustrating a configuration of a conventional fixing device, and FIG. 2B is a cross-sectional view illustrating a configuration of a fixing belt.

  Next, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified thru | or abbreviate | omitted suitably.

  FIG. 1A is a cross-sectional view illustrating a configuration of a fixing device according to an embodiment of the present invention. In FIG. 1A, the fixing device 9 is configured by a fixing belt 91 and a pressure roller 94. The fixing belt 91 is disposed on the toner image T carrying surface side of the transfer paper P. A halogen heater 84 is disposed inside the fixing belt 91 as an example of a heat source. The pressing member 83 presses the pressure roller 94 via the fixing belt 91 to form a nip portion N. The pressing member 83 is held by a holding member 65.

  A low friction sliding member 68 is disposed between the inner peripheral surface of the fixing belt 91 and the pressing member 83 in order to reduce the sliding resistance between the inner peripheral surface of the fixing belt 91 and the pressing member 83. The sliding member 68 is movable with respect to the pressing member 83 from a supply roller (supply member) 64 to a recovery roller (recovery member) 66. By rotating the collection roller 66 by a motor (not shown), the sliding member 68 moves.

  The moving direction of the sliding member 68 is preferably opposite to the rotation direction of the fixing belt 91. When the moving direction of the sliding member 68 is the same as the rotation direction of the fixing belt 91, the wear material generated by the sliding between the sliding member 68 and the inner surface of the fixing belt 91 causes a sliding portion between the sliding member 68 and the inner surface of the fixing belt 91. This is because it easily penetrates and promotes wear.

  The supply roller 64 and the collection roller 66 are provided with a brake mechanism (not shown) so that the sliding member 68 does not move except when necessary. The braking direction is both the forward and reverse directions of the moving direction of the sliding member 68. The passing time of the transfer paper P passing through the nip portion N is detected by the presence / absence signal of the transfer paper P of a transfer paper detecting member (not shown), and the transfer paper passing time (transfer from the transfer paper detecting member) is detected by an integrating means (not shown). The paper presence detection time) is integrated, and the rotation of the motor for moving the sliding member 68 is controlled by a command from the control unit.

  Alternatively, based on the print job information (paper size, paper feed direction, paper thickness, number of prints), the transfer paper P passing time through the nip portion N is determined by the transfer unit passage time (transfer paper) by the control unit (not shown). The transfer paper presence detection time from the detection member) is integrated, and the rotation of the motor for moving the sliding member 68 is controlled by a command from the control unit.

  The pressure roller 94 is disposed so as to face the fixing belt 91, and is configured to rotate in the direction of arrow D by a driving motor (not shown) so that the fixing belt 91 is driven to rotate. The pressure roller 94 includes a cored bar 941, a heat-resistant elastic body layer 942 coated on the outer peripheral surface of the cored bar 941, and a release layer 943 formed of a heat-resistant resin coating or a heat-resistant rubber coating. Has been.

  The fixing belt 91 is an endless belt whose original shape is formed in a cylindrical shape, and as shown in FIG. 1B, a base formed of a heat-resistant resin such as polyimide, polyamide, or polyimideamide, or a metal such as SUS or nickel. A layer 911 and a release layer 912 made of a fluororesin or the like coated on the pressure roller 94 side surface or both surfaces of the base layer 911 are configured. A heat resistant elastic layer 913 may be provided between the base layer 911 and the release layer 912 (outermost layer).

  The sliding member 68 is a heat-resistant resin nonwoven fabric, a heat-resistant resin film, a liquid crystal polymer sheet, a liquid crystal polymer film, a porous resin fiber woven fabric, a porous resin film, a glass fiber sheet, etc., and the heat-resistant resin is PTFE (polytetrafluoroethylene: polytetrafluoroethylene). Ethylene), PET (polyethylene terephthalate), fluorine, etc. are used. The thickness of the sliding member 68 is suitably 20 μm to 100 μm due to restrictions such as layout. The sliding member 68 may be impregnated with silicone oil, heat resistant grease or the like as a lubricant.

  The passing time of the transfer paper P passing through the nip portion N is detected by the presence / absence signal of the transfer paper P of a transfer paper detecting member (not shown), and the transfer paper passing time (transfer from the transfer paper detecting member) is detected by an integrating unit (not shown). (Paper presence detection time) is integrated and a motor for moving the sliding member 68 is operated by a command from the control unit every preset paper passing time, and the sliding member 68 is moved by a preset amount. Move.

  The preset paper passing time is changed according to paper type (particularly paper thickness) information and rotation speed information of the fixing belt 91. For example, when thick paper is set and the nip width is increased, it is necessary to reset the preset paper passing time by increasing the paper thickness and the nip pressure by increasing the nip. .

  When the rotation speed of the fixing belt 91 is slowed down, the rotation speed of the fixing belt 91 is slowed down, so that the sliding between the sliding member 68 and the inner surface of the fixing belt 91 is lowered. Although there is an effect of extending the sheet passing time, the pressure in the nip increases as the sheet thickness increases, and the sliding of the inner surface of the sliding member 68 and the fixing belt 91 increases. Needs to be set shorter. Or, based on the print job information (paper size, paper feeding direction, paper thickness, number of prints), the control unit (not shown) calculates the passage time of the transfer paper P that passes through the nip portion N.

  After a transition from a printing operation to a non-printing state by a command from a control member (not shown), a motor for moving the sliding member 68 is operated by a command from a control unit (not shown), and a predetermined amount is set. The sliding member 68 is moved. The preset paper passing time is changed according to paper type (particularly paper thickness) information and rotation speed information of the fixing belt 91. For example, when thick paper is set and the nip width is increased, it is necessary to reset the preset paper passing time by increasing the paper thickness and the nip pressure by increasing the nip. .

  Further, it is detected by a detection member (not shown) that the transfer paper P is not passing through the nip portion N, and a motor for moving the sliding member 68 is operated and set in advance by a command from a control member (not shown). The sliding member 68 is moved by the specified amount. The preset paper passing time is changed according to paper type (particularly paper thickness) information and rotation speed information of the fixing belt 91. For example, when thick paper is set and the nip width is increased, it is necessary to reset the preset paper passing time by increasing the paper thickness and the nip pressure by increasing the nip. .

  In the case where the rotation speed of the fixing belt 91 is decreased, the rotation speed of the fixing belt 91 is decreased, so that sliding between the sliding member 68 and the inner surface of the fixing belt 92 is reduced. Although there is an effect of extending the paper time, the pressure in the nip increases as the paper thickness increases, and the sliding of the inner surface of the sliding member 68 and the fixing belt 92 increases. It is necessary to set again shortly.

  Further, the passage time of the transfer paper P passing through the nip portion N is detected by the presence / absence signal of the transfer paper P of a transfer paper detection member (not shown), and the transfer paper passage time (from the transfer paper detection member) by an integration unit of a control portion (not shown). (Transfer sheet presence detection time) is integrated, and after a preset sheet passing integration time, after a transition from a printing operation to a non-printing operation state by a command from a control member (not shown), control (not shown) is performed. The motor for moving the sliding member 68 is operated according to a command from the unit, and the sliding member 68 is moved by a preset amount.

  The preset sheet passing time is changed by rotation speed information of the fixing belt 91 (changed according to the sheet thickness or the like). For example, when thick paper is set and the rotation speed of the fixing belt 91 is slowed to ensure fixing performance, the sliding between the sliding member 68 and the inner surface of the fixing belt 92 decreases. I need to fix it.

  Alternatively, the passage time of the transfer paper P passing through the nip portion N is detected by a presence / absence signal of a transfer paper detection member (not shown), and the transfer paper passage time (there is transfer paper from the transfer paper detection member) by an integration unit (not shown). Detection time) is integrated, and at each preset paper passing time, it is detected by a detection member (not shown) that the transfer paper P is not passing through the nip N, and a slide is detected by a command from a control member (not shown). A motor for moving the moving member 68 is operated to move the sliding member 68 by a preset amount.

  The preset paper passing time is changed according to paper type (particularly paper thickness) information and rotation speed information of the fixing belt 91. For example, when thick paper is set and the nip width is increased, it is necessary to reset the preset paper passing time by increasing the paper thickness and the nip pressure by increasing the nip. .

  In the case where the rotation speed of the fixing belt 91 is decreased, the rotation speed of the fixing belt 91 is decreased, so that sliding between the sliding member 68 and the inner surface of the fixing belt 91 is reduced. Although it has the effect of extending the paper time, the pressure in the nip increases as the paper thickness increases, and the sliding between the sliding member 68 and the inner surface of the fixing belt 91 increases. It is necessary to set again. Or, based on the print job information (paper size, paper feeding direction, paper thickness, number of prints), the control unit (not shown) calculates the passage time of the transfer paper P that passes through the nip portion N.

  The supply roller 64 is obtained by winding a sliding member 68 around a supply roller shaft in a roll shape, and the collection roller 66 is configured to wind the sliding member 68 by rotating the collection roller shaft.

  Next, another embodiment for carrying out the present invention will be described in detail with reference to the drawings. FIG. 2A is a cross-sectional view showing a configuration of a fixing device according to another embodiment of the present invention. In FIG. 2A, the fixing device 9 is configured by the fixing belt 91 and the pressure roller 94. The fixing belt 91 is disposed on the toner image T carrying surface side of the transfer paper P. A ceramic heater 82 which is a resistance heating element as an example of a heat generation source is disposed inside the fixing belt 91, and heat is supplied from the ceramic heater 82 to the nip portion N.

  The ceramic heater 82 is pressed against the pressure roller 94 via the fixing belt 91 to form a nip portion N. The ceramic heater 82 also has a function as a pressing member. A low friction sliding member 68 is disposed between the inner peripheral surface of the fixing belt 91 and the ceramic heater 82 in order to reduce the sliding resistance between the inner peripheral surface of the fixing belt 91 and the ceramic heater 82. .

  The sliding member 68 is movable from the supply roller (supply member) 64 to the recovery roller (recovery member) 66 with respect to the ceramic heater 82 that also functions as a pressing member. By rotating the collection roller 66 by a motor (not shown), the sliding member 68 moves.

  The moving direction of the sliding member 68 is preferably opposite to the rotation direction of the fixing belt 91. When the moving direction of the sliding member 68 is the same as the rotation direction of the fixing belt 91, the wear material generated by the sliding between the sliding member 68 and the inner surface of the fixing belt 91 causes a sliding portion between the sliding member 68 and the inner surface of the fixing belt 91. This is because it easily penetrates and promotes wear.

  The supply roller 64 and the collection roller 66 are provided with a brake mechanism (not shown) so that the sliding member 68 does not move except when necessary. The braking direction is both the forward and reverse directions of the moving direction of the sliding member 68. The passing time of the transfer paper P passing through the nip portion N is detected by the presence / absence signal of the transfer paper P of a transfer paper detection member (not shown), and the transfer paper passage time (from the transfer paper detection member) by an integration unit of a control unit (not shown). The transfer paper presence detection time) is integrated, and the rotation of the motor for moving the sliding member 68 is controlled by a command from the control unit.

  Alternatively, based on the print job information (paper size, paper feed direction, paper thickness, number of prints), the transfer paper P passing time through the nip portion N is determined by the transfer unit passage time (transfer paper) by the control unit (not shown). The detection time (transfer sheet presence from the detection member) is integrated, and the rotation of the motor for moving the sliding member 68 is controlled by a command from the control unit.

  The pressure roller 94 is disposed so as to face the fixing belt 91, and is configured to rotate in the direction of arrow D by a driving motor (not shown) so that the fixing belt 91 is driven to rotate. The pressure roller 94 is configured by laminating a cored bar 941, a heat-resistant elastic body layer 942 coated on the outer peripheral surface of the cored bar 941, and a release layer 943 made of heat-resistant resin coating or heat-resistant rubber coating. ing.

  The fixing belt 91 is an endless belt whose original shape is formed in a cylindrical shape. As shown in FIG. 2B, a base formed of a heat-resistant resin such as polyimide, polyamide, or polyimideamide, or a metal such as SUS or nickel. A layer 911 and a release layer 912 made of a fluororesin or the like coated on the pressure roller 94 side surface or both surfaces of the base layer 911 are configured. A heat resistant elastic layer 913 may be provided between the base layer 911 and the release layer 912 (outermost layer).

  The sliding member 68 is a heat resistant resin nonwoven fabric, a heat resistant resin film, a liquid crystal polymer sheet, a liquid crystal polymer film, a porous resin fiber woven fabric, a porous resin film, a glass fiber sheet, etc., and the heat resistant resin is PTFE, PET, fluorine or the like. Is used. The thickness of the sliding member 68 is suitably 20 μm to 100 μm due to restrictions such as layout. The sliding member 68 may be impregnated with silicone oil, heat resistant grease or the like as a lubricant.

  The passing time of the transfer paper P passing through the nip portion N is detected by the presence / absence signal of the transfer paper P of a transfer paper detection member (not shown), and the transfer paper passage time (from the transfer paper detection member) by an integration unit of a control unit (not shown). The transfer sheet presence detection time) is integrated, and a motor for moving the sliding member 68 is operated by a command from the control unit every preset paper passing time, and the sliding member 68 is moved by a preset amount. Move.

  The preset paper passing time is changed according to paper type (particularly paper thickness) information and rotation speed information of the fixing belt 91. For example, when thick paper is set and the nip width is increased, it is necessary to reset the preset paper passing time by increasing the paper thickness and the nip pressure by increasing the nip. .

  In the case where the rotation speed of the fixing belt 91 is slowed down, the rotation speed of the fixing belt 91 is slowed down, so that sliding between the sliding member 68 and the inner surface of the fixing belt 91 is reduced. Although it has the effect of extending the paper time, the pressure in the nip increases as the paper thickness increases, and the sliding between the sliding member 68 and the inner surface of the fixing belt 91 increases. It is necessary to set again. Or, based on the print job information (paper size, paper feeding direction, paper thickness, number of prints), the control unit (not shown) calculates the passage time of the transfer paper P that passes through the nip portion N.

  After a transition from a printing operation to a non-printing state by a command from a control member (not shown), a motor for moving the sliding member 68 is operated by a command from a control unit (not shown) to set a preset amount. Only the sliding member 68 is moved. The preset paper passing time is changed according to paper type (particularly paper thickness) information and rotation speed information of the fixing belt 91.

  For example, when thick paper is set and the nip width is increased, it is necessary to reset the preset paper passing time by increasing the paper thickness and the nip pressure by increasing the nip. . When the rotation speed of the fixing belt 91 is decreased, the rotation speed of the fixing belt 91 is decreased, and the sliding of the sliding member 68 and the inner surface of the fixing belt 91 is reduced. Although it has the effect of lengthening the time, the pressure in the nip rises as the paper thickness increases, and the sliding between the sliding member 68 and the inner surface of the fixing belt 91 rises. It is necessary to redo.

  Further, the passage time of the transfer paper P passing through the nip portion N is detected by the presence / absence signal of the transfer paper P of a transfer paper detection member (not shown), and the transfer paper passage time (from the transfer paper detection member) by an integration unit of a control portion (not shown). (Transfer sheet presence detection time) is integrated, and after a preset sheet passing integration time, after a transition from a printing operation to a non-printing operation state by a command from a control member (not shown), control (not shown) is performed. The motor for moving the sliding member 68 is operated by a command from the unit, and the sliding member 68 is moved by a preset amount.

  The preset sheet passing time is changed by rotation speed information of the fixing belt 91 (changed according to the sheet thickness or the like). For example, when thick paper is set and the rotation speed of the fixing belt 91 is slowed to ensure fixing performance, the sliding between the sliding member 68 and the inner surface of the fixing belt 91 is lowered, so that the preset paper passing time is set longer. There is a need.

  Alternatively, the passage time of the transfer paper P passing through the nip portion N is detected by a presence / absence signal of a transfer paper detection member (not shown), and the transfer paper passage time (transfer paper from the transfer paper detection member) is detected by an integrating unit (not shown). The detection member (not shown) detects that the transfer paper P is not passing through the nip portion N every preset paper passing time, and is detected by a command from a control member (not shown). Then, the motor for moving the sliding member 68 is operated to move the sliding member 68 by a preset amount.

  The preset paper passing time is changed according to paper type (particularly paper thickness) information and rotation speed information of the fixing belt 91. For example, when thick paper is set and the nip width is increased, it is necessary to reset the preset paper passing time by increasing the paper thickness and the nip pressure by increasing the nip. .

When the rotation speed of the fixing belt 91 is decreased, the rotation speed of the fixing belt 91 is decreased, and the sliding of the sliding member 68 and the inner surface of the fixing belt 91 is reduced. Although it has the effect of lengthening the time, the pressure in the nip rises as the paper thickness increases, and the sliding between the sliding member 68 and the inner surface of the fixing belt 91 rises. It is necessary to redo.
Or, based on the print job information (paper size, paper feeding direction, paper thickness, number of prints), the control unit (not shown) calculates the passage time of the transfer paper P that passes through the nip portion N.

  The supply roller 64 is obtained by winding a slide member 68 around a supply roller shaft in a roll shape, and the collection roller 66 is configured to wind the slide member 68 by rotating the collection roller shaft.

  Next, still another embodiment for carrying out the present invention will be described in detail with reference to the drawings. FIG. 3A is a cross-sectional view illustrating a configuration of a fixing device according to still another embodiment of the present invention. In FIG. 3A, the fixing device 9 is configured by a fixing roller 91 and a pressure belt 94. The fixing roller 91 is arranged on the transfer paper P on the toner image T carrying surface side. A halogen heater 84 is disposed inside the fixing roller 91 as an example of a heat source.

  The fixing roller 91 is made of a heat-resistant resin material (fluororesin) coated on an aluminum or iron-based metal core (coated or inserted into a tube), or a heat-resistant rubber coated on an aluminum or iron-based metal core. Alternatively, a heat-resistant rubber is coated on an aluminum or iron-based metal core, and a heat-resistant resin (fluororesin) is coated on the outside.

  The pressing member 83 presses the fixing roller 91 via the pressure belt 94 to form a nip portion N. A low friction sliding member 68 is disposed between the inner peripheral surface of the pressure belt 94 and the pressing member 83 in order to reduce the sliding resistance between the inner peripheral surface of the pressure belt 94 and the pressing member 83. ing. The sliding member 68 can move from the supply roller (supply member) 64 to the recovery roller (recovery member) 66 with respect to the pressing member 83. By rotating the collection roller 66 by a motor (not shown), the sliding member 68 moves.

  The moving direction of the sliding member 68 is preferably opposite to the rotating direction of the pressure belt 94. When the moving direction of the sliding member 68 is the same as the rotation direction of the pressure belt 94, the wear material generated by the sliding of the sliding member 68 and the inner surface of the pressure belt 94 is caused by the friction between the sliding member 68 and the inner surface of the pressure belt 94. This is because it easily enters the sliding portion and promotes wear.

  The supply roller 64 and the collection roller 66 are provided with a brake mechanism (not shown) so that the sliding member 68 does not move except when necessary. The braking direction is both the forward and reverse directions of the moving direction of the sliding member 68. The passing time of the transfer paper P passing through the nip portion N is detected by the presence / absence signal of the transfer paper P of a transfer paper detection member (not shown), and the transfer paper passage time (from the transfer paper detection member) by an integration unit of a control unit (not shown). The transfer paper presence detection time) is integrated, and the rotation of the motor for moving the sliding member 68 is controlled by a command from the control unit.

  Alternatively, based on the print job information (paper size, paper feed direction, paper thickness, number of prints), the transfer paper P passing time through the nip portion N is determined by the transfer unit passage time (transfer paper) by the control unit (not shown). The transfer paper presence detection time from the detection member) is integrated, and the rotation of the motor for moving the sliding member 68 is controlled by a command from the control unit.

  The fixing roller 91 is disposed so as to face the pressure belt 94, and is configured to rotate in the direction of arrow D by a drive motor (not shown) so that the pressure belt 94 is driven to rotate. The pressure belt 94 is an endless belt whose original shape is formed in a cylindrical shape. As shown in FIG. 3B, the pressure belt 94 is formed of a heat-resistant resin such as polyimide, polyamide, or polyimideamide, or a metal such as SUS or nickel. The base layer 911 and a release layer 912 made of a fluororesin or the like coated on the surface or both surfaces of the base layer 911 on the fixing roller 91 side. A heat resistant elastic layer 913 may be provided between the base layer 911 and the release layer 912 (outermost layer).

  The sliding member 68 is a heat resistant resin nonwoven fabric, a heat resistant resin film, a liquid crystal polymer sheet, a liquid crystal polymer film, a porous resin fiber woven fabric, a porous resin film, a glass fiber sheet, etc., and the heat resistant resin is PTFE, PET, fluorine or the like. Is used. The thickness of the sliding member 68 is suitably 20 μm to 100 μm due to restrictions such as layout. The sliding member 68 may be impregnated with silicone oil, heat resistant grease or the like as a lubricant.

  The passing time of the transfer paper P passing through the nip portion N is detected by the presence / absence signal of the transfer paper P of a transfer paper detection member (not shown), and the transfer paper passage time (from the transfer paper detection member) by an integration unit of a control unit (not shown). The transfer sheet presence detection time) is integrated, and a motor for moving the sliding member 68 is operated by a command from the control unit every preset paper passing time, and the sliding member 68 is moved by a preset amount. To move.

  The preset paper passing time is changed according to paper type (particularly paper thickness) information and rotation speed information of the pressure belt 94. For example, when thick paper is set and the nip width is increased, it is necessary to reset the preset paper passing time by increasing the paper thickness and the nip pressure by increasing the nip. .

  When responding by reducing the rotation speed of the pressure belt 21, since the rotation speed of the pressure belt 21 decreases and the sliding between the sliding member 68 and the inner surface of the pressure belt 94 decreases, it is set in advance. Although the sheet passing time is increased, the pressure in the nip increases as the sheet thickness increases, and the sliding between the sliding member 68 and the inner surface of the pressure belt 94 increases. It is necessary to set the time short again. Or, based on the print job information (paper size, paper feed direction, paper thickness, number of prints), the passage time of the transfer paper P passing through the nip portion N is calculated by a control unit (not shown).

  After a transition from a printing operation to a non-printing state by a command from a control member (not shown), a motor for moving the sliding member 68 is operated by a command from a control unit (not shown) to set a preset amount. Only the sliding member 68 is moved. The preset paper passing time is changed according to the paper type (particularly paper thickness) information and the rotation speed information of the pressure belt 94.

  For example, when thick paper is set and the nip width is increased, it is necessary to reset the preset paper passing time by increasing the paper thickness and the nip pressure by increasing the nip. . In the case of responding by reducing the rotation speed of the pressure belt 94, since the rotation speed of the pressure belt 94 decreases, the sliding of the sliding member 68 and the inner surface of the pressure belt 94 decreases. Although the sheet passing time is increased, the pressure in the nip increases as the sheet thickness increases, and the sliding between the sliding member 68 and the inner surface of the pressure belt 94 increases. It is necessary to set the time short again.

  A detection member (not shown) detects that the transfer paper P is not passing through the nip N, and a motor for moving the sliding member 68 is operated by a command from a control member (not shown) to set a predetermined amount. Only the sliding member 68 is moved. The preset paper passing time is changed according to paper type (particularly paper thickness) information and rotation speed information of the pressure belt 94.

  For example, when thick paper is set and the nip width is increased, it is necessary to reset the preset paper passing time by increasing the paper thickness and the nip pressure by increasing the nip. . In the case of responding by reducing the rotation speed of the pressure belt 94, since the rotation speed of the pressure belt 94 decreases, the sliding of the sliding member 68 and the inner surface of the pressure belt 94 decreases. Although the sheet passing time is increased, the pressure in the nip increases as the sheet thickness increases, and the sliding between the sliding member 68 and the inner surface of the pressure belt 94 increases. It is necessary to set the time short again.

  The passing time of the transfer paper P passing through the nip portion N is detected by the presence / absence signal of the transfer paper P of a transfer paper detecting member (not shown), and the transfer paper passing time (transfer from the transfer paper detecting member) is detected by an integrating unit (not shown). Paper presence detection time) is integrated, and after each preset paper passing integration time, after a transition from a printing operation to a non-printing operation state by a command from a control member (not shown), a control unit (not shown) In response to the command, the motor for moving the sliding member 68 is operated to move the sliding member 68 by a preset amount.

  The preset sheet passing time is changed by the rotation speed information of the pressure belt 21 (changed according to the paper thickness or the like). For example, when thick paper is set and the rotation speed of the pressure belt 94 is slowed to ensure fixing properties, the sliding between the sliding member 68 and the inner surface of the pressure belt 94 decreases, so a preset paper passing time is set long. Can be redone.

  Alternatively, the passage time of the transfer paper P passing through the nip portion N is detected by a presence / absence signal of a transfer paper detection member (not shown), and the transfer paper passage time (transfer paper from the transfer paper detection member) is detected by an integrating unit (not shown). The detection member (not shown) detects that the transfer paper P is not passing through the nip N every preset paper passing time, and by a command from a control member (not shown), The motor for moving the sliding member 68 is operated to move the sliding member 68 by a preset amount.

  The preset paper passing time is changed according to the paper type (particularly paper thickness) information and the rotation speed information of the pressure belt 94. For example, when thick paper is set and the nip width is increased, it is necessary to reset the preset paper passing time by increasing the paper thickness and the nip pressure by increasing the nip. .

When responding by reducing the rotation speed of the pressure belt 94, the rotation speed of the pressure belt 94 decreases, and sliding between the sliding member 68 and the inner surface of the pressure belt 94 decreases. However, as the paper thickness increases, the pressure in the nip increases and the sliding between the sliding member 68 and the inner surface of the pressure belt 94 increases. It is necessary to set the paper time short again.
Or, based on the print job information (paper size, paper feeding direction, paper thickness, number of prints), the control unit (not shown) calculates the passage time of the transfer paper P that passes through the nip portion N.

  The supply roller 64 is obtained by winding a slide member 68 around a supply roller shaft in a roll shape, and the collection roller 66 is configured to wind the slide member 68 by rotating the collection roller shaft.

   FIG. 4 shows an image forming apparatus provided with the fixing device 9 in the embodiment of the present invention shown in FIGS. FIG. 4 is a cross-sectional view showing the overall configuration of the image forming apparatus including the fixing device according to the embodiment of the present invention. In FIG. 4, a contact glass 43 made of a translucent member is provided on the upper surface of the main body of the copier 202 capable of color printing. The upper surface of the main body adjacent to the contact glass 43 is smaller than the contact glass 43. A slit glass 42 made of a translucent member having an area is provided.

  Further, an automatic document feeder (hereinafter also referred to as “ADF (Auto Document Feeder)”) 201 is provided at the upper part of the copying machine 202, and the ADF 201 is connected to the contact glass 43 via a hinge mechanism (not shown). It can be opened and closed freely.

  The ADF 201 takes out the documents d placed on the document table 12, separates them one by one and conveys them to the reading position, and discharges the documents d after reading onto the document discharge trays 28 and 29. The paper feed belt 39 and the separation roller 40 are configured to separate and feed (convey) the originals d taken out from the original table 12 one by one. A conveyance roller such as the reverse roller 41 conveys the document d to a reading position on the slit glass 42.

  Document length sensors 30 and 31 (a reflection type sensor or an actuator type sensor that can detect even one document) are arranged so as to determine the approximate length in the conveyance direction of the document d. ing. The ADF controller determines at least whether the document size is vertical or horizontal based on signals from the document length sensors 30 and 31.

  On the other hand, a scanner unit 301 as an image reading unit is provided below the contact glass 43 on the upper surface of the copying machine 202. The scanner unit 301 has a reduction optical system using a CCD (Charge Coupled Device) image sensor. is doing. Image information read by the scanner unit 301 is read from the photosensitive drum 1Y for each color (Y (yellow: yellow), M (magenta: magenta), C (cyan: cyan), K (black)) by the writing unit. 1M, 1C, and 1K are irradiated.

  The scanner unit 301 includes a light source (not shown) that illuminates the document (or document bundle) d on the contact glass 43 or the slit glass 42, a first mirror (not shown), a second mirror (not shown) that reflects light reflected from the document d, respectively. A third mirror, a lens (not shown) that focuses the light reflected from the third mirror on the CCD image sensor, and a CCD image sensor that converts the light imaged by the lens into an electrical signal are provided.

  The light source and the first mirror are attached to a first traveling body (not shown), and the second mirror and the third mirror are attached to a second traveling body (not shown). The first traveling body and the second traveling body move to the left and right in FIG. 4 along the guide rails (not shown) disposed below both side portions below the contact glass 43 and the slit glass 42. It has become.

  When the first traveling body and the second traveling body read the document placed on the contact glass 43, the first traveling body and the second traveling body are moved in the horizontal direction in FIG. 4 below the contact glass 43 and read the document passing through the slit glass 42. Sometimes, it stops below the slit glass 42. An image reading unit (scanner unit) 301 can read an image (including characters (text), figures, photographs, and the like) displayed on a document.

  The laser devices 3Y, 3M, 3C, and 3K irradiate the surfaces of the charged photosensitive drums 1Y, 1M, 1C, and 1K with laser beams of four colors that are light-modulated according to image information read by the scanner unit 301 ( Exposure).

  Around the photosensitive drums 1Y, 1M, 1C, and 1K, developing devices 4Y, 4M, 4C, and 4K that constitute image forming means together with the photosensitive drum, transfer belt 6, cleaning devices 8Y, 8M, 8C, and 8K, charging Devices 2Y, 2M, 2C, 2K, a static eliminator (not shown), and the like are provided. The charging devices 2Y, 2M, 2C, and 2K control positively charged corona discharge with a grid to charge the surfaces of the photosensitive drums 1Y, 1M, 1C, and 1K to a constant potential.

  The laser devices 3Y, 3M, 3C, and 3K irradiate the photosensitive drums 1Y, 1M, 1C, and 1K charged with a constant potential with laser light including image information to remove negative charges on the photosensitive drums. To form an electrostatic latent image.

  The developing devices 4Y, 4M, 4C, and 4K form a visible image (unfixed toner image) by attaching a negatively charged toner to a portion of the photosensitive drum from which the negative charge has been removed. A positive bias is applied to the transfer belt 6, and the transfer belt 6 transfers a negatively charged visible image onto a transfer sheet (paper) as a recording medium for conveyance.

  The cleaning devices 8Y, 8M, 8C, and 8K include a cleaning blade that scrapes off the toner remaining on the photosensitive drums 1Y, 1M, 1C, and 1K. The static eliminator turns on an LED (Light Emitting Diode) to remove residual charges on the photoconductive drums 1Y, 1M, 1C, and 1K, and prepares to form a new image on the next transfer sheet.

  In addition, in the main body of the copying machine 202, a paper feed cassette 20 in which transfer papers P of different sizes are stored is provided. The transfer paper P stored in the paper feed cassette 20 is fed by the paper feed belt 21, is slidably contacted with the paper feed belt 21, and is separated by a reverse roller that rotates in the separation direction. The separated transfer paper P is conveyed to the registration roller 23 via the paper feed roller 22, and is timed by the registration roller 23 to be conveyed to the nip portion between the transfer roller 7 </ b> A and the transfer belt 6. Here, the unfixed toner image is transferred from the transfer belt 6 to the transfer paper P as described above.

  The transfer paper P onto which the unfixed toner image has been transferred is conveyed to the fixing device 9 according to the above-described embodiment of the present invention, where the toner is dissolved by the fixing device 9 and the unfixed toner image is fixed to the transfer paper P. The The fixing device 9 includes a fixing belt 91 having a built-in heat source and a pressure roller 94, and performs fixing processing (heating and pressing) while passing the transfer paper P through the nip portion N of both.

  As described above, according to the present invention, the moving amount of the sliding member is changed in accordance with the integrated value of the passage time of the recording medium passing through the nip portion formed by pressing of the fixing member and the pressure member. Since the sliding resistance generated by the contact between the fixing member and the sliding member can be maintained in a good state, it is possible to obtain a fixing device and an image forming apparatus in which the durability of the fixing member, the pressing member, and the sliding member is improved. it can.

  Further, according to the present invention, the sliding member is moved or stopped in accordance with the integrated value of the passage time of the recording medium that passes through the nip formed by the pressing of the fixing member and the pressure member. Since the sliding resistance generated by the contact between the fixing member and the sliding member can be maintained in a good state, it is possible to obtain a fixing device and an image forming apparatus in which the durability of the fixing member, the pressing member, and the sliding member is improved. it can.

  Furthermore, according to the present invention, the fixing is performed by moving or stopping the sliding member according to the paper type information of the recording medium passing through the nip formed by the pressing of the fixing member and the pressure member. Since the sliding resistance generated by contact between the member and the sliding member can be maintained in a good state, the sliding resistance is prevented from increasing with time, and the durability of the fixing member, the pressing member, and the sliding member is improved. A fixing device and an image forming apparatus can be obtained.

  Further, according to the present invention, the sliding member is set according to the integrated value of the passing time of the recording medium passing through the nip formed by the pressing of the fixing member and the pressing member and / or the paper type information of the recording medium. By moving or stopping, the sliding resistance generated by the contact between the fixing member and the sliding member can be maintained in a good state, thereby preventing the sliding resistance from increasing over time. In addition, it is possible to obtain a fixing device and an image forming apparatus in which durability of the sliding member is improved.

  According to the present invention, the sliding member is moved or stopped depending on whether or not the recording medium passes through the nip formed by the pressing of the fixing member and the pressing member. Accordingly, it is possible to obtain a fixing device and an image forming apparatus that can prevent the occurrence of rotation unevenness of the fixing member caused by the movement of the sliding member, transfer sheet wrinkles due to vibration, and image disturbance.

  According to the present invention, the sliding member has a start end and a terminal end, a supply member is provided on the start end side, a recovery member is provided on the end side, and a pressing member is provided between the supply member and the recovery member. Since the sliding member is supplied from the supply member and collected to the collecting member, the sliding member is prevented from increasing in sliding resistance over time, and the durability of the fixing member, the pressing member, and the sliding member is prevented. It is possible to obtain a fixing device and an image forming apparatus that improve the image quality.

  The present invention has been described above by the preferred embodiments of the present invention. While the invention has been described with reference to specific embodiments, it will be appreciated that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the invention as defined in the claims. It is.

12 Document table 1Y, 1M, 1C, 1K Photosensitive drum 20 Paper cassette 21 Paper feed belt 22 Paper feed roller 23 Registration roller 24 Paper discharge roller 28, 29 Document paper output tray 201 ADF
202 Copier 2Y, 2M, 2C, 2K Charging Device 3 Writing Unit 30, 31 Document Length Sensor 39 Paper Feed Belt 301 Image Reading Unit (Scanner Unit)
302 Image forming unit 303 Paper feeding unit 3Y, 3M, 3C, 3K Laser device 40 Separating roller 41 Reversing roller 42 Slit glass 43 Contact glass 4Y, 4M, 4C, 4K Developing device 6 Transfer belt 64 Supply roller (supply member)
65 Holding member 66 Collection roller (collection member)
68 Sliding member 7A, 7Y, 7M, 7C, 7K Transfer roller 82 Ceramic heater 83 Press member 84 Halogen heater 8Y, 8M, 8C, 8K Cleaning device 9 Fixing device 91 Fixing belt 93 Heat source 94 Pressure roller (Pressure belt)
911 Base layer 912, 943 Release layer 913, 942 Heat resistant elastic layer 941 Core

JP 2001-228731 A

Claims (7)

A fixing device comprising: a fixing member; and a pressure member that forms a nip portion so as to face the fixing member, and fixes an unfixed toner image on a recording medium that passes through the nip portion,
A pressing member which is provided inside the fixing member and presses the pressing member from the inside of the fixing member;
A sliding member that moves a predetermined distance between the fixing member and the pressing member;
Time measuring means for measuring an accumulated time for the recording medium to pass through the nip portion,
The fixing device according to claim 1, wherein the predetermined distance that the sliding member moves changes in accordance with the accumulated time. A fixing device comprising: a fixing member; and a pressure member that forms a nip portion so as to face the fixing member, and fixes an unfixed toner image on a recording medium that passes through the nip portion,
A pressing member which is provided inside the fixing member and presses the pressing member from the inside of the fixing member;
A sliding member that moves between the fixing member and the pressing member;
Switching means for switching the sliding member to a moving state or a stopped state;
Time measuring means for measuring an accumulated time for the recording medium to pass through the nip portion,
The fixing device, wherein the switching unit switches the sliding member to a moving state or a stopped state corresponding to the accumulated time. A fixing device comprising: a fixing member; and a pressure member that forms a nip portion so as to face the fixing member, and fixes an unfixed toner image on a recording medium that passes through the nip portion,
A pressing member which is provided inside the fixing member and presses the pressing member from the inside of the fixing member;
A sliding member that moves between the fixing member and the pressing member;
Switching means for switching the sliding member to a moving state or a stopped state;
Discriminating means for discriminating the type of the recording medium,
The fixing device is characterized in that the switching unit switches the sliding member to a moving state or a stopped state corresponding to the type of the recording medium. A fixing device comprising: a fixing member; and a pressure member that forms a nip portion so as to face the fixing member, and fixes an unfixed toner image on a recording medium that passes through the nip portion,
A pressing member which is provided inside the fixing member and presses the pressing member from the inside of the fixing member;
A sliding member that moves between the fixing member and the pressing member;
Switching means for switching the sliding member to a moving state or a stopped state;
Time measuring means for measuring an accumulated time for the recording medium to pass through the nip portion;
Discriminating means for discriminating the type of the recording medium,
The fixing device, wherein the switching unit switches the sliding member to a moving state or a stopped state in accordance with the accumulated time and / or the type of the pre-recording medium. A fixing device comprising: a fixing member; and a pressure member that forms a nip portion so as to face the fixing member, and fixes an unfixed toner image on a recording medium that passes through the nip portion,
A pressing member which is provided inside the fixing member and presses the pressing member from the inside of the fixing member;
A sliding member that moves between the fixing member and the pressing member;
Switching means for switching the sliding member to a moving state or a stopped state;
Detecting means for detecting whether or not the recording medium passes through the nip portion,
The fixing device, wherein the switching unit switches the sliding member to a moving state or a stopped state when the detecting unit detects that the recording medium does not pass through the nip portion. The sliding member has a starting end and a terminal end, a supply member that supplies the sliding member to the starting end of the sliding member, and a recovery member that collects the sliding member at the terminal of the sliding member The fixing device according to claim 1, wherein the sliding member moves between the supply member and the recovery member. An image forming apparatus comprising the fixing device according to claim 1.

Images