JP2007304180A - Image heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image heating device which allows a cleaning means to perform press-contacting and removing operations for one or both surfaces of first and second rotators at a low-cost and with a simple constitution without requiring an actuator, etc. additionally. <P>SOLUTION: The image heating device includes: the cleaning means which performs press-contacting and removing operations between the first rotator 31 and the second rotator 32 by rotation of a cam shaft 50 rotated by a driving source 70 and is disposed on one or both of the first and second rotators; and cam means 51/50 which perform press-contacting and removing operations for the first and second rotators. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image heating apparatus suitable for use as an image heating and fixing apparatus mounted on an image forming apparatus such as an electrophotographic copying machine or an electrophotographic printer.

  Conventionally, as an image heating fixing device (fixing device) mounted on an electrophotographic image forming apparatus such as a copying machine or a laser beam printer, a fixing roller, a heater disposed in the fixing roller and heating the fixing roller, and fixing And a pressure roller that forms a nip portion in contact with the roller. Patent Document 1 describes this type of fixing device. The sheet carrying the unfixed toner image is heated while being nipped and conveyed by the nip portion of the fixing device, whereby the toner image on the sheet is heated and fixed to the sheet.

  In the fixing device, it is ideal that all the toner images on the sheet are fixed to the sheet in a fixing process in which the toner image is heat-fixed on the sheet. However, due to the characteristics of the sheet itself, temperature factors during fixing, and electrostatic factors, a small amount of toner is not sufficiently fixed to the sheet and is transferred to the outer peripheral surface (surface) of the fixing roller (or pressure roller). May end up. In addition, when performing so-called borderless printing for forming an image over the entire sheet surface, the toner may wrap around the end surface (cut surface) of the sheet when the toner image is transferred to the sheet. In some cases, it may be transferred to the surface of the fixing roller or the pressure roller.

  When the toner is transferred to the surface of the fixing roller or the pressure roller, the toner adheres to the sheet again as an offset toner, and the sheet image surface or the sheet back surface is soiled.

  As a means for preventing this offset, there is one in which a cleaning roller as a cleaning means is pressed against the surface of the fixing roller (or pressure roller). This cleaning roller collects and accumulates toner on the surface of the fixing roller. However, if the cleaning roller is always pressed against the surface of the fixing roller, the remaining toner adheres to the pressure contact portion between the fixing roller and the cleaning roller when the fixing roller cools, and the toner adheres to the fixing roller side during reheating. May end up. Conversely, if heating is continued while the cleaning roller is pressed against the surface of the fixing roller, the temperature of the cleaning roller rises to a temperature close to that of the fixing roller, and the toner on the cleaning roller melts at a high temperature, making it easy to flow back to the fixing roller. The sheet may become dirty.

Therefore, Patent Document 1 proposes a mechanism for separating the cleaning roller from the surface of the fixing roller (or pressure roller). As an example of the cleaning roller separation mechanism, a technique as shown in FIG. 10 is used. In this technique, an actuator 154 such as a solenoid is provided to freely press and separate the cleaning roller 153 from the surface of the fixing roller 151.
JP-A-5-224555 (FIG. 2)

  Since the cleaning roller separating mechanism in the conventional fixing device requires a dedicated actuator such as a solenoid, the cost tends to increase as a whole.

  The object of the present invention is to press and separate the cleaning means against the surface of one or both of the first and second rotating bodies at a low cost and with a simple configuration without requiring a new actuator or the like. An object of the present invention is to provide an image heating apparatus which can be operated.

A typical configuration of the image heating apparatus according to the present invention includes a first rotating body, a second rotating body that forms a nip portion in contact with the first rotating body, and the first and second rotations. An image heating apparatus that heats an image on a recording medium while sandwiching and conveying the recording medium at the nip portion, the heating means configured to heat at least one of the bodies. In an image heating apparatus provided with a cleaning means for cleaning each surface on one or both of the rotating bodies,
A driving source; a camshaft rotated by the driving source; and a cam member provided on the camshaft, wherein rotation of the camshaft causes the first rotating body and the second rotating body to An image heating apparatus, comprising: a pressing member and a separating member; and a cam member that performs a pressing member and a separating member with respect to the first rotating member or the second rotating member. is there.

  According to the present invention, the cleaning means is pressed against and separated from the surface of one or both of the first and second rotating bodies at a low cost and with a simple configuration without requiring a new actuator or the like. An image heating apparatus which can be operated can be provided.

  Hereinafter, the present invention will be described with reference to the drawings.

(1) Example of Image Forming Apparatus FIG. 1 is a structural model diagram of an example of an image forming apparatus equipped with an image heating apparatus according to the present invention.

  The image forming apparatus of this embodiment is an electrophotographic full color laser printer (hereinafter simply referred to as “printer”).

  A full-color laser printer (hereinafter simply referred to as “printer”) configuration will be described.

  The printer according to the present exemplary embodiment includes a sheet supply device 20 below a printer main body (image forming apparatus main body) 100 constituting a housing of the printer. In the sheet supply device 20, sheets S such as recording paper as recording media stored in the sheet supply cassette 21 are separated and fed one by one from the cassette 21 as the pickup roller 22 rotates counterclockwise in the figure. The paper is conveyed to the registration roller pair 25 through the paper feed roller 23 and the retard roller 24. Then, it is conveyed to the secondary transfer unit 17 by the registration roller pair 25 at a predetermined timing. A registration sensor 26 detects the leading edge of the sheet S immediately after the registration roller pair 25.

  An image forming unit 8 is provided above the sheet supply apparatus 20 in the printer main body 100. In the image forming unit 8, four drum-type electrophotographic photosensitive members (hereinafter referred to as photosensitive drums) 1a, 1b, corresponding to the respective colors of yellow, magenta, cyan, and black in the substantially horizontal direction are used. 1c and 1d (hereinafter, the symbol “1” is used when generically referring to the photosensitive drum). The photosensitive drum 1 is rotated clockwise in the figure by driving means (not shown).

  Around the photosensitive drum 1, charging devices 2 a, 2 b, 2 c, 2 d (hereinafter, the charging device is collectively referred to as “2”) and scanner units 3 a, 3 b, 3 c in order according to the rotation direction. , 3d (hereinafter, the symbol “3” is used when generically referring to the scanner unit). Further, the developing devices 4a, 4b, 4c, 4d (hereinafter, the reference numeral “4” is used when the developing devices are collectively referred to) and the cleaning devices 6a, 6b, 6c, 6d (hereinafter, the cleaning devices are collectively referred to as the reference “ 6 ”is used. The charging device 2 uniformly charges the outer peripheral surface (surface) of the photosensitive drum 1. An electrostatic latent image is formed on the charged surface of the photosensitive drum 1 by irradiating the charged surface on the surface of the photosensitive drum 1 with a laser beam based on the image information of each color by the scanner unit 3. The developing device 4 develops the electrostatic latent image as a toner image (developed image) by attaching toners (developers) of yellow, magenta, cyan, and black to the electrostatic latent image on the photosensitive drum 1.

  Here, the photosensitive drum 1, the charging device 2, the developing device 4, and the cleaning device 6 are integrally formed into a cartridge, and the process cartridges 7 a, 7 b, 7 c, and 7 d (hereinafter, the process cartridge is collectively referred to as “7”). Use). The cartridge 7 is detachably attached to the printer main body 100.

  An intermediate transfer device 10 is disposed at the opposite portion of the photosensitive drum 1 so that the intermediate transfer belt 11 is in contact with each photosensitive drum 1. The intermediate transfer belt 11 is formed of a thin film member having a predetermined volume specific resistance. The intermediate transfer belt 11 is stretched around three rollers of a driving roller 12 and driven rollers 13 and 14 and rotates counterclockwise in the drawing.

  Inside the intermediate transfer belt 11, primary transfer rollers 15a, 15b, 15c, and 15d (hereinafter collectively referred to as primary transfer rollers) that face the four photosensitive drums 1 and contact the inner surface of the intermediate transfer belt 11, respectively. The code “15” is used). The primary transfer roller 15 transfers yellow, magenta, cyan, and black toner images from the surface of the photosensitive drum 1 to the surface of the intermediate transfer belt 11 at a primary transfer portion that is in contact with the inner surface of the intermediate transfer belt 11.

  The surface of the photosensitive drum 1 to which the toner image is transferred is cleaned by the cleaning device 6 after removal of the transfer residual toner, and is repeatedly used for the next image formation.

  A secondary transfer roller 16 is disposed at a position facing the driving roller 12 of the intermediate transfer device 10 and is pressed against the surface of the intermediate transfer belt 11 with a predetermined pressure to form a secondary transfer portion 17. The secondary transfer roller 16 transfers yellow, magenta, cyan, and black toner images from the surface of the intermediate transfer belt 11 to the sheet S surface in the secondary transfer unit 17.

  The sheet S that has received the transfer of the toner image at the secondary transfer portion is conveyed and introduced to the image heating and fixing device 30 as a heating device through the conveyance guide 18 and undergoes a heating and pressure fixing process of the toner image.

  The sheet S that has passed through the fixing device 30 is transported by the transport roller pair 27 to the paper discharge roller pair 29 through the transport guide 28. Then, the sheet discharge roller pair 29 discharges the sheet onto a sheet discharge tray 101 provided on the upper portion of the printer main body 100.

(2) Fixing device 30
FIG. 2 is a schematic cross-sectional view of an example of the fixing device 30. FIG. 3 is a structural model diagram illustrating the separation mechanism portion of the fixing device 30. FIG. 4 is a longitudinal center omitted model diagram illustrating the separation mechanism portion and the drive transmission mechanism portion of the fixing device 30. FIG. 5 is an explanatory view of the cam surfaces of the pressure release cam 51 and the cleaning separation cam 52.

  The fixing device 30 of this embodiment includes a fixing roller 31 as a first rotating body (fixing rotating body), a pressure roller 32 as a second rotating body (pressing rotating body), a fixing roller 31 and an additional roller. Halogen heaters 33 and 34 are provided as heating means provided inside the pressure roller 32, respectively. As cleaning means, a fixing cleaning roller 35 for cleaning the surface of the fixing roller 31 and a pressure cleaning roller 36 for cleaning the surface of the pressure roller 32 are provided. Further, thermistors 37 and 38 for detecting the surface temperatures of the fixing roller 31 and the pressure roller 32 are arranged at a certain distance from the roller surface as temperature detecting means. The fixing roller 31, the pressure roller 32, the heaters 33 and 34, the fixing cleaning roller 35, and the pressure cleaning roller 36 are elongated members in the direction perpendicular to the sheet conveying direction on the surface of the sheet S, respectively.

  The fixing roller 31 includes, in order from the inside, a metal pipe-shaped core 31a and an elastic layer 31b made of heat-resistant silicon rubber, and a release layer 31c made of a fluorine-based resin such as PFA on its surface. Yes. Both longitudinal end portions 31a1 of the core bar 31a are formed to have a smaller diameter than the longitudinal central portion, and are rotatably held by the fixing frame 40 via bearings (not shown) such as bearings. A heater holder 31A is provided at both longitudinal end portions 31a1 of the metal core 31a so as to close the opening of the longitudinal both end portions 31a1. And as for the heater 33 provided in the inside of the metal core 31a, the nozzle | cap | die of the longitudinal both ends is hold | maintained by the heater holder 31A.

  Similarly to the fixing roller 31, the pressure roller 32 includes a metal pipe-shaped cored bar 32 a and an elastic layer 32 b made of heat-resistant silicon rubber in order from the inside, and the surface thereof is made of a fluorine-based resin such as PFA. A release layer 32c is provided. Both longitudinal end portions 32a1 of the cored bar 32a are formed to have a smaller diameter than the longitudinal central portion, and are rotatably supported by a pressure arm 41 disposed inside the frame 40 via a bearing (not shown) such as a bearing. . A heater holder 32A is provided at both longitudinal ends 32a1 of the metal core 32a so as to close the openings of the longitudinal both ends 32a1. And the heater 34 provided in the inside of the metal core 32a has the caps at both longitudinal ends held by the heater holder 32A.

  The pressure arm 41 is rotatably supported by the frame 40 via a shaft 42 so that the pressure roller 32 can be brought into contact with and separated from the fixing roller 31. A pressure spring 43 as a pressure means is provided between the pressure arm 41 and the frame 40 on the opposite side of the shaft 42, and the pressure arm 41 is urged toward the fixing roller 31 by the pressure spring 43. ing. Due to this urging force, the pressure roller 32 comes into contact with the pressure applied to the fixing roller 31 to form a nip portion (pressure nip portion, fixing nip portion) N having a predetermined width with the fixing roller 31.

  Here, if the fixing roller 31 and the pressure roller 32 are left in pressure contact, the elastic layers 31b and 32b of the respective rollers 31 and 32 may be permanently deformed in the nip portion N. The apparatus 30 also includes a mechanism for separating the pressure roller 32 from the fixing roller 31.

a) Separation mechanism of the pressure roller 32 The separation operation of the pressure roller 32 is performed by the rotational movement of the cam shaft 50 that is driven by a motor 70 as a drive source described later.

  The cam shaft 50 is disposed in parallel with the fixing roller 31 above the fixing roller 31, and both longitudinal ends thereof are rotatably supported by the frame 40 via bearings (not shown). A pressure release cam 51 is fixedly held near the end of the cam shaft 50 inside the frame 40. A roller 44 is rotatably supported by a shaft 45 at a portion of the pressure arm 41 facing the pressure release cam 51.

  In a pressure roller separation mechanism including a roller 44 provided on the pressure arm 41 and a pressure release cam 51 provided on the cam shaft 50, the cam surface provided on the outer peripheral surface of the pressure release cam 51. Rolling contact with 51a (FIG. 5). Then, the pressure arm 41 rotates counterclockwise around the shaft 42 to separate the pressure roller 32 from the fixing roller 31.

b) Contact / Separation Mechanism of Cleaning Rollers 35 and 36 The fixing cleaning roller 35 has a function of cleaning and collecting the offset toner or the like adhering to the outer peripheral surface (surface) of the fixing roller 31, that is, the release layer 31a. In general, since toner is transferred from a higher surface release property to a lower one, one of the conditions is that the surface material of the cleaning roller 35 is inferior to the release layer 31a. Here, a solid aluminum roller is used as the fixing cleaning roller 35. The same applies to the pressure cleaning roller 36.

  The fixing cleaning roller 35 disposed in parallel with the fixing roller 31 inside the frame 40 is rotatably held at one end of the first link arm 55. The first link arm 55 is rotatably supported on the frame 40 by a shaft 56 and is urged against the fixing roller 31 by a spring 57 with a predetermined pressure. The fixing cleaning roller 35 is pressed against the surface of the fixing roller 31 by this urging force.

  The pressure cleaning roller 36 disposed in parallel with the pressure roller 32 inside the frame 40 is rotatably held at one end of the second link arm 58. The second link arm 58 is rotatably supported on the pressure arm 41 by a shaft 59 and is urged against the pressure roller 32 by a spring 60 with a predetermined pressure. The pressure cleaning roller 36 is in pressure contact with the surface of the pressure roller 32 by this urging force.

  A pin 61 is formed at the other end of the second link arm 58 so as to be in contact with the cleaning separation cam 52 fixedly held by the cam shaft 50. A contact portion 62 is formed at the other end of the first link arm 55 so as to contact the lower side of the pin 61. The cleaning separation cam 52 has a large-diameter portion 52a (FIG. 5) that contacts the outer peripheral surface of the pin 61 and pushes down the pin 61 as a cam surface on the outer peripheral surface, and a small-diameter portion 52b (FIG. 5) that does not contact the pin 61. It has two places.

  In a cleaning roller contact / separation mechanism including a first link arm 55 having a fixing cleaning roller 35, a second link arm 58 having a pressure cleaning roller 36, and a cleaning separation cam 52 provided on the cam shaft 50. The cam shaft 50 rotates counterclockwise. Then, as shown in FIG. 3, the pin 61 is pushed down by the large-diameter portion 52 a of the cleaning separation cam 52 to rotate the second link arm 58 about the shaft 59 in the counterclockwise direction. Thereby, the pressure cleaning roller 36 is separated from the surface of the pressure roller 32 (FIG. 2). At the same time, the pin 61 contacts the contact portion 62 of the first link arm 55 to rotate the first link arm 55 clockwise about the shaft 56. As a result, the fixing cleaning roller 35 is separated from the surface of the fixing roller 31 (FIG. 2).

  A sensor S serving as a rotation amount detecting means for detecting the rotation amount of the cam shaft 50 is provided on one end side of the cam shaft 50. The sensor S includes a circular sensor flag 65 fixed to the camshaft 50, and a photo sensor 66 that detects the sensor flag. The photo sensor 66 is attached to the frame 40. FIG. 6 is an explanatory diagram of the flag 65 and the sensor 66.

  As shown in FIG. 6, the flag 65 is provided with notches 65 a to 65 d for detecting the rotation amount of the pressure release cam 51 and the cleaning separation cam 52. The notches 65a to 65d are detected by the sensor 65, and the detection signal Sa is input to the CPU 81 as the control means. Based on the detection signal Sa, the CPU 81 outputs a drive control signal Sb to the motor 70 to control driving of the motor 70 so as to selectively switch four operation states (I) to (IV) described later. .

c) Driving Mechanism of Fixing Roller 31 and Cam Shaft 50 In FIG. 4, a motor 70 that is the only driving source for driving each part of the fixing device 30 is fixed to the main body frame 71. The rotational drive of the motor 70 is transmitted from the motor gear 70 a to the gear 72 and the gear shaft 73. A one-way gear 74 and a one-way gear 75 are fitted on the gear shaft 73. In the one-way gear 74 and the one-way gear 75, one-way clutches 74a and 75a are incorporated so that the locking directions are opposite to each other.

  With this configuration, when the motor 70 rotates in the direction of the solid arrow A1, the one-way clutch 74a is locked and the one-way clutch 75a becomes free, so that the drive is transmitted only to the one-way gear 74. The driving of the one-way gear 74 is transmitted to a gear 78 fixed to one end 31a1 of the core 31a of the fixing roller 31 through the gear 77, and the fixing roller 31 is rotated counterclockwise (FIG. 2). Due to the rotation of the fixing roller 31, a rotational force acts on the pressure roller 32 by the frictional force between the surface of the fixing roller 31 and the surface of the pressure roller 32 in the nip portion N. The pressure roller 32 has a rotational peripheral speed of the fixing roller 31. Driven in the clockwise direction at approximately the same peripheral speed (FIG. 2).

  Conversely, when the motor 70 rotates in the direction of the broken line arrow A2, the one-way clutch 75a is locked and the one-way clutch 74a becomes free, so that the drive is transmitted only to the one-way gear 75. The drive of the one-way gear 75 is transmitted to a gear 79 attached to one end of the cam shaft 50, and the cam shaft 50 is rotated counterclockwise (FIG. 3).

d) Description of the operation state of the fixing roller 31 and the pressure roller 32 and the operation state of the fixing cleaning roller 35 and the pressure cleaning roller 36 FIG. 7 shows the operation of the pressure roller separation mechanism and the cleaning roller contact / separation mechanism. It is a figure showing a state.

  (I) shows a state in which the fixing roller 31 and the pressure roller 32 are separated from each other, and the fixing cleaning roller 35 and the pressure cleaning roller 36 are separated from each other.

  (II) shows a state in which the fixing roller 31 and the pressure roller 32 are separated from each other, and the fixing cleaning roller 35 and the pressure cleaning roller 36 are in contact with the fixing roller 31 and the pressure roller 32, respectively.

  (III) shows a state in which the fixing roller 31 and the pressure roller 32 are in contact with each other, and the fixing cleaning roller 35 and the pressure cleaning roller 36 are separated from each other.

  (IV) shows a state where the fixing roller 31 and the pressure roller 32 are in contact with each other, and the fixing cleaning roller 35 and the pressure cleaning roller 36 are also in contact with the fixing roller 31 and the pressure roller 32, respectively.

  When the camshaft 50 is rotated once in the direction of the arrow A3 (counterclockwise), the mechanism returns to (I) again through the states (I) to (IV) in order. The rotation control of the cam shaft 50 is performed by controlling the driving of the motor 70 by the CPU 81 so that the sensor 65 detects all the notches 65a to 65d of the flag 65.

e) Description of Operation of Fixing Device 30 FIG. 8 is a flowchart for explaining the operation of the fixing device 30.

  First, when the printer is turned off, it is in the state (I). This is to prevent permanent deformation of the elastic layers 31b and 32b of the fixing roller 31 and the pressure roller 32 and to prevent the toner collected by the cleaning rollers 35 and 36 from adhering to the surface of the fixing roller 31 or the surface of the pressure roller 32. It is.

  When the printer power is turned on (S1), the state shifts to the state (III) (S2), the halogen heaters 33 and 34 are turned on, and the warm-up is performed until the fixing roller 31 is heated to a predetermined temperature. (S3, S4).

  When the print signal is received (Yes in S5), the CPU 81 determines whether the state of (III) can be kept or the state of (IV) is shifted according to the contents of the print instruction. Normally, printing is performed in the state of (III) (S7, S8). For example, when performing borderless printing or printing an image with a particularly high printing rate, the fixing roller 31 and the pressure roller 32 When cleaning is necessary (Yes in S6), the state shifts to the state (IV) (S9).

  When the printer is turned on, in FIG. 2, heaters 33 and 34 are supplied with power from a driving power source 90 to heat the surface of the fixing roller 31 and the surface of the pressure roller 32. The thermistors 37 and 38 disposed on the surface side of the fixing roller 31 and the pressure roller 32 detect the temperature of each roller surface, and the temperature control circuit 91 controls the drive power supply 90 on / off based on the detected temperature. Thus, temperature control is performed (print preparation) so that the surface temperature of each roller becomes a predetermined fixing temperature (target temperature).

  When the fixing device 30 is ready to print, in FIG. 1, the sheet S is separated and fed one by one by the sheet feeding device 20, and the leading edge of the sheet S is moved by the registration sensor 26 provided immediately after the nip of the registration roller pair 25. When the sheet is detected, the sheet feeding is temporarily stopped. On the other hand, the process cartridges 7 are also sequentially driven to form the respective color toner images and sequentially transfer them onto the intermediate transfer belt 11, thereby completing the superposition of the four color toner images. Then, sheet feeding is resumed by the registration roller pair 25 in accordance with the timing of the toner image on the intermediate transfer belt 11, and the toner image is transferred to the sheet S by the secondary transfer unit 17.

  Thereafter, the sheet S is conveyed upward along the leading edge of the conveyance guide 18, guided to the fixing device 30, and nipped and conveyed by the nip portion N to the heated fixing roller 31 and pressure roller 32. The toner image is fixed on the sheet S surface. The sheet S that has passed through the fixing nip is conveyed by the conveying roller pair 27 and the conveying guide 28, and is discharged onto the sheet discharging tray 101 by the discharging roller pair 29 (S10, S11).

  In the state of (9) in S9, the offset toner remaining on the surface of the fixing roller 31 or the surface of the pressure roller 32 is simultaneously collected by the fixing cleaning roller 35 and the pressure cleaning roller 36.

  When the printing is completed and the state (IV) is left, the fixing cleaning roller 35 and the pressure cleaning roller 36 are recovered due to excessive heat due to the heat transmitted from the fixing roller 31 and the pressure roller 32. The toner melts. When the toner melts, the toner may return from the fixing cleaning roller 35 to the surface of the fixing roller 31 and from the pressure cleaning roller 36 to the surface of the pressure roller 32, so that the state returns to the state (III) again and waits ( S12).

  When the sleep mode is set in the printer, if no print signal is input for a certain time in S5 (Yes in S13), the fixing device 30 is shifted to the state (I), and power is supplied to the heaters 33 and 34. It narrows down and shifts to the sleep mode (S13).

  Further, when a sheet jam occurs during printing, even when there is a sheet in the fixing device 30, the state moves to the state (I) so that the user can easily remove the jammed sheet, and the pressure roller 32 is moved to the fixing roller 31. Separate from. Further, even when the sheet is wound around the fixing roller 31 or the pressure roller 32, the fixing cleaning roller 35 and the pressure cleaning roller 36 are separated from each other, so that the jam processing is facilitated.

  When a print signal is received (S15), the process proceeds to the state (III) according to the contents of the print instruction.

  As described above, the cleaning rollers 35 and 36 that further clean the surfaces of the fixing roller 31 and the pressure roller 32 by using the rotation of the cam shaft 50 that performs the pressure contact / separation operation between the fixing roller 31 and the pressure roller 32. The pressure contact / separation operation can also be performed. That is, since the cam shaft 50 for separating the pressure roller 32 can be used as a contact / separation mechanism for the cleaning rollers 35, 36, the contact between the cleaning rollers 35, 36 can be achieved at low cost and with a simple configuration.・ Separation can be performed.

  Further, during the one rotation of the camshaft 50 in one direction, the operation state of the fixing roller 31 and the pressure roller 32 and the operation state of the cleaning rollers 35 and 36 are combined from the above four combinations (I) to (IV). Any operating state can be selected. That is, only by controlling the amount of rotation of the motor 70 in one direction, four combinations of (I) to (IV) of the separation operation state of the pressure roller 32 and the contact / separation operation state of the cleaning rollers 35 and 36 are performed. Any operating state can be selected.

  Further, the drive source of the cam shaft 50 can be made the same as the drive source for rotationally driving the fixing roller 31 and the pressure roller 32.

  Next, an embodiment in which the fixing device 30 described in the first embodiment is partially changed will be described. In the following description, parts similar to those in the previous embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIG. 9 is a front view illustrating the separation mechanism unit of the fixing device 110 according to the present exemplary embodiment.

  In the fixing device 110, cleaning pads 111 and 112 are brought into contact with the fixing roller 31 and the pressure roller 32 in place of the cleaning rollers 35 and 36.

  The cleaning pads 111 and 112 are felt-like pads made of heat-resistant fibers, and the offset toner recovery capability is better than that of the cleaning rollers 35 and 36. As in the first embodiment, the contact and separation states of the cleaning pads 111 and 112 can be freely selected in conjunction with the separation mechanism of the pressure roller 32.

[Others]
1) In each of the embodiments, the cleaning rollers 35 and 36 and the cleaning pads 111 and 112 have been described as cleaning means. However, application to other cleaning means such as a cleaning web is also possible.

  2) In each embodiment, the fixing roller 31 and the pressure roller 32 are each provided with a cleaning unit, but it is of course possible to provide a cleaning unit only on either the fixing roller 31 or the pressure roller 32. .

  3) The fixing devices 30 and 110 of the embodiment are not limited to full-color laser printers, but can be mounted on a single-color printer or a copying machine.

1 is a configuration model diagram of an example of an image forming apparatus. 1 is a cross-sectional model diagram of an example of a fixing device according to Embodiment 1. FIG. FIG. 3 is a structural model diagram illustrating a separation mechanism unit of the fixing device according to the first exemplary embodiment. 3 is a longitudinal center omitted model diagram illustrating a separation mechanism section and a drive transmission mechanism section of the fixing device 30 according to Embodiment 1. FIG. It is explanatory drawing of the cam surface of a pressure release cam and a cleaning separation cam. FIG. 3 is an explanatory diagram of flags and sensors of the fixing device according to the first exemplary embodiment. FIG. 5 is a diagram illustrating an operation state of a pressure roller separation mechanism and a cleaning roller contact / separation mechanism of the fixing device according to the first exemplary embodiment. 6 is a flowchart for explaining the operation of the fixing device 30 according to the first embodiment. FIG. 6 is a structural model diagram of an example of a fixing device according to a second embodiment. It is a structural model figure of the conventional fixing device.

Explanation of symbols

30, 110 ... fixing device, 31 ... fixing roller, 32 ... pressure roller,
33, 34 ... Halogen heaters 33, 34, 35 ... Fixing cleaning roller,
36 ... Pressure cleaning roller, 50 ... Cam shaft, 51 ... Pressure release cam,
52 ... Cleaning separation cam, 55 ... First link arm, 58 ... Second link arm 65 ... Sensor flag, 66 ... Photo sensor, 81 ... CPU,
111, 112 ... cleaning pad, S ... sheet, T ... toner

Claims (4)

A first rotating body, a second rotating body that forms a nip portion in contact with the first rotating body, and a heating unit that heats at least one of the first and second rotating bodies. An image heating apparatus that heats an image on a recording medium while nipping and conveying the recording medium at the nip portion, wherein one or both of the first and second rotating bodies are provided with respective surfaces. In an image heating apparatus provided with a cleaning means for cleaning,
A driving source; a camshaft rotated by the driving source; and a cam member provided on the camshaft, wherein rotation of the camshaft causes the first rotating body and the second rotating body to An image heating apparatus, comprising: a pressing member and a separating member; and a cam member for performing a pressing member and a separating member with respect to the first rotating member or the second rotating member. Furthermore, when the pressure contact and separation operation state of the first rotating body and the second rotation body is A, and the pressure contact and separation operation state of the cleaning means is B,
(I) A separation, B separation (II) A separation, B pressure welding (III) A pressure welding, B separation (IV) A pressure welding, and B pressure welding at least four operating states (I) to (IV) 2. The image heating apparatus according to claim 1, further comprising a control unit that controls driving of the driving source so as to be selectively switched by rotation of a cam shaft.   The control means controls the drive of the drive source so as to select all the states (I) to (IV) while the camshaft is rotated once in one direction. Item 3. The image heating apparatus according to Item 2.   4. The image according to claim 1, wherein the driving source for rotating the cam shaft is the same as the driving source for rotating the first rotating body or the second rotating body. 5. Heating device.