JP5058584B2 - Fixing device - Google Patents

Description

The present invention relates to a fixing device that heats an image on a recording medium while nipping and conveying the recording medium at a nip portion between a fixing rotating body and a pressure rotating body , which is a fixing rotating body. In particular, comprising a cleaning means for cleaning the surface of at least either one of the fixing rotator and the pressure rotating body, about the fixing equipment for fixing an unfixed toner image on the recording material.

  2. Description of the Related Art Conventionally, an image heating apparatus mounted on an electrophotographic image forming apparatus such as a copying machine or a laser beam printer, that is, as a fixing apparatus, a fixing roller (fixing rotating body) and a pressure roller (pressing rotating body) Some types have At least in the fixing roller, a heater (heating means) for heating the fixing roller is disposed, and the pressure roller forms a nip portion in contact with the fixing roller.

  Patent Document 1 describes this type of fixing device. A sheet (recording medium) carrying an unfixed toner image is heated while being nipped and conveyed by the nip portion of the fixing device, whereby the unfixed 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 in which an image is formed 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. Also in this case, the toner on the end face of the sheet 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 back surface of the sheet is soiled.

  As a means for preventing this offset, there is a means in which a cleaning roller as a cleaning means is brought into pressure contact with the surface of a fixing roller (or a pressure roller) as described in Patent Document 1. This cleaning roller collects toner on the surface of the fixing roller.

  However, when the toner transferred to the fixing roller is collected by the cleaning roller, the offset toner is merely attached to the surface of the cleaning roller and collected. Therefore, there is a problem that when a certain amount or more of offset toner accumulates on the surface of the cleaning roller, it melts and reattaches to the fixing roller side.

  One example of a configuration corresponding to these is a configuration in which a pad, a roller, or the like is brought into contact with a cleaning roller as means for accumulating collected toner (see, for example, Patent Document 2).

By providing the means for accumulating the toner, the toner adhering to the surface of the cleaning roller can be collected by the accumulating means during one rotation of the cleaning roller, so that the offset toner continues to accumulate on the surface of the cleaning roller. In addition, the lifetime of the cleaning performance can be extended.
JP-A-5-224555 Japanese Patent Laid-Open No. 7-295424

  The present invention relates to a further improvement when the means for accumulating the offset toner is performed by a pad.

  In the conventional fixing device described above, when the toner collected by the cleaning roller is collected by rubbing against the pad in contact with the cleaning roller, the toner accumulates on the pad. As the toner accumulates on the pad, the sliding resistance between the pad and the cleaning roller gradually increases. The cleaning roller has no drive means and is driven by the rotation of the fixing roller. Therefore, if the frictional force generated between the cleaning roller and the pad exceeds the frictional force generated between the cleaning roller and the fixing roller, cleaning is performed. The roller does not follow the fixing roller.

  When the cleaning roller is not driven, the cleaning roller does not collect the offset toner on the fixing roller, so that the offset toner rotated once is fixed on the sheet.

  In the current configuration, the cleaning life until the cleaning performance is lowered is generally shorter than the life of the fixing device.

  Therefore, it is necessary to replace only the cleaning member such as the cleaning roller and the cleaning pad, which are cleaning means, at any timing. However, it takes a certain amount of time to purchase and replace the cleaning member, and there is a problem that the printer cannot be used while the cleaning member is replaced.

  If printing is forcibly performed, the cleaning roller does not follow, so that the surface of the fixing roller is damaged.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device capable of printing a certain number of sheets even when a cleaning member, which is a cleaning means for a fixing rotating body , reaches the end of its life in order to solve the above problems.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device in which the surface of the fixing rotator is not damaged even when a cleaning member that is a cleaning means for the fixing rotator reaches the end of its life.

The above object is achieved by the fixing device according to the present invention. In summary, according to one aspect of the present invention, the fixing rotator, the cleaning rotator that contacts the fixing rotator and rotates following the fixing rotator, and the cleaning that contacts the cleaning rotator. A fixing device that includes a pad and a cleaning unit that cleans the surface of the fixing rotating body, and heat-fixes an unfixed toner image on the recording medium on the recording medium.
The cleaning means is provided to be replaceable with respect to the device,
Wherein as the cleaning rotor and the cleaning pad the cleaning rotary member in a spaced apart condition is rotated by the fixing rotary member, it has a separation mechanism for moving the cleaning pad,
The separation mechanism has an operation unit operated by a user,
When the user operates the operation unit, the cleaning pad is separated from the cleaning rotator, and the cleaning rotator is rotated following the fixing rotator in a state where the cleaning rotator and the cleaning pad are separated from each other,
The apparatus has a life detecting means for detecting the life of the cleaning means, and when the life detecting means detects the life of the cleaning means, a message prompting replacement of the cleaning means and a user operating the operation unit. A fixing device is provided that displays a message prompting the user on a display unit of a printer in which the device is mounted .

According to another aspect of the present invention, there is provided a fixing rotator, a cleaning rotator that contacts the fixing rotator and rotates following the fixing rotator, and a cleaning pad that contacts the cleaning rotator. And a cleaning unit that cleans the surface of the fixing rotating body, and a fixing device that heat-fixes an unfixed toner image on the recording medium to the recording medium.
A separation mechanism for moving one of the cleaning rotator and the cleaning pad so that the cleaning rotator is rotated by the fixing rotator in a state where the cleaning rotator and the cleaning pad are separated from each other; Have
The separation mechanism includes a holding member that holds the cleaning rotator at a first position where the cleaning rotator contacts both the fixing rotator and the cleaning pad.
When toner accumulates on the cleaning pad and the sliding resistance of the cleaning pad with respect to the cleaning rotator increases, the rotation of the fixing rotator releases the cleaning rotator from the holding state by the holding member, and the fixing rotation. Moving to a second position different from the first position in the rotation direction of the body, and the cleaning rotator is driven to rotate by the fixing rotator while the cleaning rotator and the cleaning pad are separated from each other. A featured fixing device is provided.

According to the present invention, either one of the cleaning pad and cleaning rotating body constituting a cleanup means for cleaning the fixing rotary member is moved is configured to cleaning pad and cleaning the rotating body is separated. Therefore, even when the cleaning means reaches the end of its service life, a certain number of prints can be made and printing can be continued until the user purchases and replaces the cleaning means.

Further, according to the present invention, when the conventional apparatus to continue printing after the cleaning means reaches the end of its life, the surface of a fixing rotary member there is a possibility that hurt, even such a problem It will be resolved.

Hereinafter, the fixing device according to the present invention will be described in more detail with reference to the drawings.

Example 1
(1) Overall Configuration of Image Forming Apparatus First, the overall configuration of an embodiment of an image forming apparatus provided with a fixing device according to the present invention will be described.

FIG. 1 is a schematic configuration diagram of an embodiment of an image forming apparatus equipped with a fixing device according to the present invention.

  In this embodiment, the image forming apparatus is an electrophotographic full-color laser printer (hereinafter simply referred to as “printer”).

  The printer 100 according to the present exemplary embodiment includes a sheet supply device 20 at a lower portion of a printer main body (image forming apparatus main body) 100 </ b> A 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 drawing. . The separated sheet S 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. Immediately after the registration roller pair 25, a registration sensor 26 for detecting the leading edge of the sheet S is installed.

  In the printer main body 100A, a plurality of, in the present embodiment, four image forming units 8 (8a, 8b, 8c, and 8d) that constitute image forming means are provided above the sheet feeding device 20. The image forming units 8a, 8b, 8c, and 8d are image forming units corresponding to yellow, magenta, cyan, and black, respectively. The image forming unit 8 (8a, 8b, 8c, 8d) includes four drum-type electrophotographic photosensitive members (hereinafter referred to as “photosensitive drums”) 1 (1a, 1b, 1c, 1d) as image carriers. ). Hereinafter, the symbol “8” is used to generically refer to image forming units, and the symbol “1” is used to generically refer to photosensitive drums. The photosensitive drum 1 is rotated clockwise in the figure by driving means (not shown).

  Around the photosensitive drum 1, a charging device 2 (2a, 2b, 2c, 2d) and a scanner unit 3 (3a, 3b, 3c, 3d) as an exposure device are provided in order according to the rotation direction. . Hereinafter, the symbol “2” is used to generically refer to charging devices, and the symbol “3” is used to generically refer to scanner units.

  Further, around the photosensitive drum 1, a developing device 4 (4a, 4b, 4c, 4d) and a cleaning device 6 (6a, 6b, 6c, 6d) are arranged. Hereinafter, the symbol “4” is used when generically referring to the developing device, and the symbol “6” is generically used when referring to the cleaning device.

  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 as a cartridge to form a process cartridge 7 (7a, 7b, 7c, 7d). Hereinafter, the symbol “7” is used to collectively refer to process cartridges. The cartridge 7 is detachably attached to the printer main body 100A.

  An intermediate transfer device 10 is disposed facing the image forming unit 8. The intermediate transfer device 10 includes an intermediate transfer belt 11 as an intermediate transfer member. The intermediate transfer device 10 is configured such that each photosensitive drum 1 is in contact with the intermediate transfer belt 11 at a portion opposed to the 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 15 (15 a, 15 b, 15 c, 15 d) that face the four photosensitive drums 1 and abut against the inner surface of the intermediate transfer belt 11 are arranged in parallel. . Hereinafter, the symbol “15” is used to collectively refer to the primary transfer roller. 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 has been transferred is cleaned by the transfer 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 roller 13 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 unfixed toner image in the secondary transfer unit 17 is conveyed and introduced to a fixing device 30 as an image heating device through a conveyance guide 18 and undergoes heating and pressure fixing processing of the toner image.

  The sheet S that has passed through the fixing device 30 is discharged onto the sheet discharge tray 101 by the conveying roller pair 27.

(2) Fixing Device FIG. 2 is a schematic configuration diagram of an embodiment of the fixing device 30.

  The fixing device 30 according to the present exemplary embodiment includes a fixing roller 31 as a fixing rotator, and a pressure roller 32 as a pressure rotator that forms a nip portion N in contact with the fixing roller 31. The fixing roller 31 includes a halogen heater 33 as a heating unit. A heating means 33 can be provided in the pressure roller 32 as necessary.

  According to this embodiment, the fixing device 30 further includes a cleaning unit 34 that cleans the surface of the fixing roller 31. The cleaning unit 34 includes a fixing cleaning roller 35 that is a cleaning rotating body for cleaning the surface of the fixing roller 31 and a cleaning pad (that is, a cleaning pad) 63 as cleaning members. The cleaning pad 63 is provided in pressure contact with the cleaning roller 35. The cleaning means 34 including the cleaning roller 35 and the cleaning pad 63 is unitized to form a cleaning unit and can be exchanged.

  The cleaning means 34 according to the present invention is described as being provided only on the fixing roller 31 in the following description of the embodiments, but is not limited thereto. If necessary, the pressure roller 32 can be similarly provided. In some cases, it may be provided only on the pressure roller 32.

  The fixing device 30 includes a thermistor 37 as temperature detecting means. According to this embodiment, the fixing device 30 is arranged at a certain distance from the surface of the fixing roller 31 in order to detect the surface temperature of the fixing roller 31. . The fixing roller 31 is controlled to a predetermined temperature by turning on / off the halogen heater 33 by the control means 200 based on a detection signal from the thermistor 37. Of course, when the halogen heater 33 is provided on the pressure roller 32, the thermistor 37 is also installed on the pressure roller 32 and the same control is performed.

  The fixing roller 31, the pressure roller 32, the heater 33, and the fixing cleaning roller 35 are elongated members in directions orthogonal to the sheet S conveyance direction.

  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.

  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.

(3) Life detection means The cleaning means 34 includes a life detection means 5B for detecting the life of the cleaning roller 35 and the cleaning pad 63, which are cleaning members. In this embodiment, an optical sensor is provided as the life detecting means 5B.

  According to the present embodiment, the optical sensor 5B is a rotation detection unit that monitors the rotation state (for example, the rotation speed rpm) of the cleaning roller 35. With reference to FIG. 3, the rotation and stop detection of the cleaning roller 35 and power supply control will be described.

  In this embodiment, on the outer peripheral surface on one end of the cylindrical cleaning roller 35, as shown in FIG. 3, detection marks for detecting rotation are arranged in the circumferential direction at equal intervals in a different color. C is provided. The optical sensor 5B is disposed at a position corresponding to the detection mark C of the cleaning roller 35.

  The optical sensor 5 </ b> B includes a light emitting element 51 and a light receiving element 52. The light emitted from the light emitting element 51 is reflected by the cleaning roller 35, and this is detected by the light receiving element 52. The detection marks C provided on the cleaning roller 35 are white 3 mm square and are arranged at equal intervals (about 3 mm). Accordingly, the intensity of the reflected light periodically changes due to the rotation of the cleaning roller 35, and the optical sensor 5B outputs this to the control means 200 as an electrical signal.

(4) Contact and separation mechanism and operation of cleaning roller and cleaning pad Next, with reference to FIGS. 4 and 5, fixing cleaning as a cleaning member constituting the cleaning means 34 in the fixing device 30 of this embodiment. The contact / separation mechanism of the roller 35 and the cleaning pad 63 will be described.

  As shown in FIG. 4, the fixing cleaning roller 35 has a function of cleaning and collecting the outer peripheral surface (surface) of the fixing roller 31, that is, the offset toner attached to the release layer 31c. Generally, the toner is transferred from a higher surface releasability to a lower one. Therefore, one of the conditions is that the surface material of the cleaning roller 35 is inferior to the release layer 31c.

  In this embodiment, an aluminum roller is used as the fixing cleaning roller 35. Usually, it is a sleeve-shaped roller having a diameter (d) of 8 to 15 mm and a thickness of 1 to 2.5 mm. In this embodiment, the roller is a sleeve roller having a diameter (d) of 10 mm and a thickness of 2 mm. The length in the axial direction is the same as or longer than that of the fixing roller 31. In this embodiment, since the length of the fixing roller 31 is 335 mm, the length of the cleaning roller 35 is 336 mm.

  The cleaning roller 35 was pressed against the fixing roller 31 by a pressing means such as a compression spring (not shown), 3 kgf on each side for a total of 6 kgf. The cleaning pad 63 was pressed against the cleaning roller 35 at about 8 kgf by pressing means such as a compression spring (not shown).

  Since the followability of the cleaning roller 35 and the durability of the cleaning pad 63 depend on the material and surface property of each fixing member, the above pressure is set in consideration thereof.

  The cleaning pad 63 in pressure contact with the cleaning roller 35 has a function of transferring and accumulating the toner adhering to the cleaning roller 35 to the pad itself, and has excellent durability, mechanical and electrical properties at high temperatures. It is made of a material that has special characteristics. In this embodiment, the cleaning pad 63 is made using aramid fibers. More specifically, it is a woven fabric or a non-woven fabric usually made using aramid fibers, and has a thickness (t) of 2 to 4 mm, a width (w) of 10 to 15 mm, and extends over the entire axial direction of the cleaning roller 35. The length is 250 to 330 mm. In this embodiment, a cleaning pad 63 having a thickness of 3 mm, a width of 12 mm, and a length of 310 mm is used.

  The cleaning pad 63 is attached to the sheet metal stay (support member) 64 with an adhesive. The sheet metal stay 64 is connected to one end 65b of the link member 65 that is rotatable about the rotation shaft 65a. The other end of the link member 65 is an operation portion, that is, a knob 65c, which protrudes from the frame 66 of the fixing device 30 and is usually a link cover 67 that is detachable from the apparatus main body 100A. Covered. Therefore, the user can operate by removing the link cover 67.

  As shown in FIG. 3, the rotation detecting means 5B is provided so as to detect the number of rotations of the cleaning roller 35.

  As printing continues, the cleaning pad 63 accumulates toner, and the cleaning roller 35 gradually stops following the fixing roller 31. When the rotational speed of the cleaning roller 35 falls to about 90% of the normal time, the offset toner cannot be sufficiently collected due to a reduction in cleaning ability.

  Therefore, when the rotation number of the cleaning roller 35 is reduced to 80 to 90% of the normal time, the control unit 200 that has received the signal from the rotation detection unit 5B determines that the pad 63 has a life. Then, the display unit 201 of the operation panel of the printer displays a cleaning means, that is, a message for prompting replacement of the cleaning unit 34 (the cleaning pad 63 and the cleaning roller 35) and a countermeasure method for the period until the replacement.

The contents of the coping method are as follows, for example.
(1) Open the right door (the exterior door 102 covering the fixing device 30) of the image forming apparatus main body 100A (see FIG. 1).
(2) Remove the cover 67 attached to the fixing device 30 (see FIG. 4).
(3) For example, the operating portion of the link member 65 colored in blue, that is, the knob 65c is pushed down to the bottom of the main body until it clicks (see FIG. 5).

  The cover 67 is a cover that covers only the link member 65, and is intended to prevent erroneous operation during the lifetime.

  According to the above procedure, as shown in FIG. 5, the user presses the knob 65c of the link member 65 with a finger or the like against the pressing force of the cleaning pad 63 toward the fixing cleaning roller 35. Then, the link member 65 rotates in the clockwise direction in FIG. 5 around the rotation shaft 65 a, and the cleaning pad 63 is separated from the cleaning roller 35.

  In addition, since the cleaning pad 63 in which the toner has accumulated is cooled, it adheres to the cleaning roller 35 and cannot be separated, so that the above method displays on the display unit 201 so that the fixing device 30 is hot.

  Once the cleaning pad 63 is separated from the cleaning roller 35, the link member 65 is locked by the lock member 69 and does not return to the original position but is held in a separated state.

  The lock member 69 may have an arbitrary structure, but, for example, can usually be configured such that it is urged and abutted by a spring member (not shown) on the side surface of the link member 65. In this configuration, when the link member 65 is pressed down and the link member rotates clockwise around the rotation shaft 65a, the lock member 69 protrudes below the link member 65 by the spring member, and the lower surface of the link member 65 To prevent the link member 65 from rotating counterclockwise.

  In a state where the cleaning pad 63 is separated from the cleaning roller 35, the sliding resistance between the pad 63 and the cleaning roller 35 is lost, and therefore the cleaning roller 35 is rotated by the fixing roller 31 again. Accordingly, the cleaning performance is recovered if the cleaning roller 35 collects the toner and the printing amount is a certain number of sheets. Since the user purchases and replaces the cleaning unit 34 in the meantime, the cleaning unit replacement period can also be printed.

  In this embodiment, the cleaning unit 34 includes a cleaning roller 35, a cleaning pad 63, a sheet metal stay 64, a link member 70, and left and right side plates 61 that carry these members. It is removable. Therefore, the cleaning unit 34 is also sold as a consumable like a cartridge or the like, and can be purchased and replaced by the user as needed.

Example 2
Next, another embodiment of the fixing device 30 that characterizes the image forming apparatus of the present invention will be described with reference to FIGS. Since the overall configuration of the fixing device 30 of the present embodiment is the same as that of the fixing device 30 described in the first embodiment, members having the same configuration and function are denoted by the same reference numerals as those of the fixing device described in the first embodiment. And the description in Example 1 is incorporated.

  Next, the characteristic part of the fixing device 30 in this embodiment will be described.

(1) Automatic Separation Mechanism and Operation of Cleaning Roller 35 and Cleaning Pad 63 FIG. 6 shows a separation mechanism portion of the cleaning member (cleaning roller 35 and cleaning pad 63) in the fixing device 30 of this embodiment.

  A long hole 61a is formed in the left and right side plates 61 forming the cleaning unit 34, and the rotation shaft 35a of the cleaning roller 35 is rotatably supported by the long hole 61a. The long hole 61 a is formed concentrically with the fixing roller 31, and the center distance between the cleaning roller 35 and the fixing roller 31 is determined by carrying the cleaning roller 35 in the long hole 61 a of the left and right side plates 61. . Accordingly, the distance from the fixing roller 31 can always be kept constant even when the cleaning roller 35 moves along the long hole 61a.

  The cleaning roller 35 is positioned by the rotary shaft holding member 70 when it is disposed at the lower right position (first position) of the long hole 61a in FIG.

  That is, one end 70 a of the rotation holding member 70 is rotatably supported on the rotation shaft 72. The other end (that is, the tip) 70 b includes a locking portion 70 c formed in a claw shape, and is engaged with the rotation shaft 35 a of the cleaning roller 35. Further, the rotation holding member 70 is urged counterclockwise in FIG. 6 by the compression spring 71, the engaging portion 70c engages with the rotation shaft 35a, and the cleaning roller 35 is brought to the first position of the long hole 61a. Positioning.

As described above, the rotating shaft holding member 70 holds the rotating shaft 35a of the cleaning roller 35 by the claw-shaped engaging portion 70c of the tip 70b. When the force is applied in the direction P shown in FIG. Accordingly, as shown in FIGS. 7 and 8, when the locking from the locking portion 70c is released, the cleaning roller 35 is moved to the other end (second position) of the long hole 61a by the rotation of the fixing roller 31. The

  The cleaning roller 35 was pressed against the fixing roller 31 in the same manner as in Example 1 by 3 kgf on each side for a total of 6 kgf. Further, the cleaning pad 63 was pressed against the cleaning roller 35 at about 8 kgf.

  In the present embodiment, as shown in FIG. 6, the cleaning pad 63 is substantially opposite to the contact portion between the cleaning roller 35 and the fixing roller 31 and when the cleaning roller 35 moves in the direction P, It is provided in a position that does not interfere. The cleaning pad 63 is installed by a support stay (support member) 64. As described above, the contact pressure of the cleaning pad 63 to the cleaning roller 35 is also a load of 8 kgf as in the first embodiment.

  The life detection means 5C of the cleaning roller 35 will be described in the next section.

  The frictional force acting on the cleaning member when the fixing roller 31 is rotated with the above configuration will be described with reference to FIG.

The frictional force that the cleaning roller 35 receives from the fixing roller 31 is F, the frictional force that is received from the cleaning pad 63 is f, and the circumferential component of the fixing roller 31 of the force that the rotating shaft holding member 70 holds the rotating shaft 35a is α. Then, the following relational expression is established within the cleaning life period.
F + f <α (F> f)
F and α are constant, and f increases in proportion to the increase in the amount of offset toner accumulated.

  Since the holding force (α) of the rotating shaft holding member 70 is larger than the resultant force (F + f) of the frictional force received from the fixing roller 31 and the cleaning pad 63 while the number of printed sheets is small, the rotating shaft 35a of the cleaning roller 35 is a rotating shaft. It is held by the holding member 70. Therefore, the cleaning roller 35 rotates at the first position shown in FIG. At this time, since the cleaning roller 35 is not driven and is driven by the fixing roller 31, F is larger than f.

Since the sliding resistance between the cleaning pad 63 and the cleaning roller 35 is low in a new state, F >> f. However, when the printing amount increases, the toner adheres to the sliding surface and the resistance increases. Therefore, the offset toner collected on the cleaning pad 63 is gradually accumulated, and f increases. When f continues to increase and f approaches F, the cleaning roller 35 is unable to follow the fixing roller 31 smoothly due to the braking force of the cleaning pad 63. If f is fa when the rotation speed of the cleaning roller 35 drops to about 90% of the normal time, the holding force α of the rotary shaft holding member has the following relationship between the frictional forces F and fa.
F + fa = α

  Therefore, by setting the holding force (α) of the rotary shaft holding member 70 to the relationship of the above formula, when the rotation of the cleaning roller 35 becomes awkward and the rotational speed falls to about 90% of the normal time, the following Is done.

  That is, in the cleaning roller 35, the resultant force (F + fa) of the frictional force F received from the fixing roller and the fa received from the cleaning pad 63 is equal to the holding force (α) of the rotating shaft holding member 70. Therefore, when printing is continued in this state, fa further increases, and as shown in FIG. 8, the cleaning roller 35 automatically moves over the claw-like engaging portion 70c of the rotating shaft holding member 70 and moves to the cleaning pad. Separated from 63.

  When the cleaning roller 35 is separated from the pad 63, the life detecting means 5C (details are described below) detects the life of the cleaning member, that is, the cleaning unit 34, and replaces the cleaning unit 34 on the display unit 201 of the operation panel of the printer. Display a prompt message.

  In this embodiment, since the cleaning roller 35 has already been automatically separated from the cleaning pad 63 at this time, it is not necessary for the user to perform the separation operation as in the first embodiment, and the user only replaces the cleaning unit 34. It's okay.

  The cleaning unit 34 basically has the same configuration as that of the first embodiment, and a different part is provided with a rotating shaft holding member 70 and a compression spring 71 instead of the link member 65.

(2) Life Detecting Unit Next, the life detecting unit 5C of the cleaning roller 35 according to the second embodiment will be described with reference to FIG. According to the present embodiment, the life detecting means 5C includes a light shielding member 35b and a photo interrupter 35c.

  That is, as shown in FIG. 9, a disc-shaped light shielding member 35 b is provided at one end of the cylindrical cleaning roller 35. In the light shielding member 35b, the disc-shaped end of the light shielding member 35b shields the light from the photo interrupter 35c at the position (first position) where the cleaning roller 35 is held by the rotating shaft holding member 70 and is rotated.

  Accordingly, at a position (second position) where the cleaning roller 35 is separated from the cleaning pad 63, the light shielding member 35b does not shield the photo interrupter 35c.

  With the above configuration, it is possible to detect that the cleaning roller 35 is separated from the cleaning pad 63 by the photo interrupter 35c, and it is possible to detect that the cleaning member (that is, the cleaning unit 34) has reached the end of its life.

In the above embodiments, the cleaning means 34 has been described as only provided in the fixing rotary member fixing roller (fixing rotary member) 31 is, as described above, in the present invention, is a fixing rotatable member A pressure roller (pressure rotator) 32 can also be provided. In some cases, it may be provided only on the pressure roller 32.

  In any case, since the configuration of the cleaning means 34 can be the configuration described in the first and second embodiments, further description is omitted.

1 is a schematic configuration diagram of an embodiment of an image forming apparatus according to the present invention. It is a schematic block diagram of one Example of the image heating apparatus which concerns on this invention. It is a figure for demonstrating one Example of a lifetime detection means. It is a schematic block diagram explaining one Example of the cleaning means in the image heating apparatus which concerns on this invention. It is a schematic block diagram explaining one Example of the cleaning means in the image heating apparatus which concerns on this invention. It is a schematic block diagram explaining the other Example of the cleaning means in the image heating apparatus which concerns on this invention. It is a schematic block diagram explaining the other Example of the cleaning means in the image heating apparatus which concerns on this invention. It is a schematic block diagram explaining the other Example of the cleaning means in the image heating apparatus which concerns on this invention. It is a figure for demonstrating the other Example of a lifetime detection means.

Explanation of symbols

1 Photosensitive drum (image carrier)
2 Charging device 3 Scanner unit (exposure device)
4 Developing device 5B, 5C Rotation detection means (life detection means)
7 Process Cartridge 8 Image Forming Unit 10 Intermediate Transfer Device 11 Intermediate Transfer Belt 30 Fixing Device 31 Fixing Roller (Fixing Rotator)
32 Pressure roller (Pressure rotating body)
33 Halogen heater (heating means)
34 Cleaning unit (cleaning means)
35 Cleaning roller (rotating body for cleaning)
35a Rotating shaft of cleaning roller 61 Both side plates (frame body) of cleaning unit
61a Long hole 63 Cleaning pad (cleaning pad)
64 Sheet metal stay (support member)
65 Link member 65a Center of rotation of link member 66 Fixing frame 67 Cleaning cover 69 Lock member 70 Rotating shaft holding member 71 Compression spring

Claims (2)

A fixing rotator, a cleaning rotator that contacts and rotates with the fixing rotator, and a cleaning pad that contacts the cleaning rotator and cleans the surface of the fixing rotator. A fixing device that heats and fixes an unfixed toner image on the recording medium to the recording medium.
The cleaning means is provided to be replaceable with respect to the device,
Wherein as the cleaning rotor and the cleaning pad the cleaning rotary member in a spaced apart condition is rotated by the fixing rotary member, it has a separation mechanism for moving the cleaning pad,
The separation mechanism has an operation unit operated by a user,
When the user operates the operation unit, the cleaning pad is separated from the cleaning rotator, and the cleaning rotator is rotated following the fixing rotator in a state where the cleaning rotator and the cleaning pad are separated from each other,
The apparatus has a life detecting means for detecting the life of the cleaning means, and when the life detecting means detects the life of the cleaning means, a message prompting replacement of the cleaning means and a user operating the operation unit. A fixing device that displays a message prompting the user on a display unit of a printer in which the device is mounted . A fixing rotator, a cleaning rotator that contacts and rotates with the fixing rotator, and a cleaning pad that contacts the cleaning rotator and cleans the surface of the fixing rotator. A fixing device that heats and fixes an unfixed toner image on the recording medium to the recording medium.
A separation mechanism for moving one of the cleaning rotator and the cleaning pad so that the cleaning rotator is rotated by the fixing rotator in a state where the cleaning rotator and the cleaning pad are separated from each other; Yes, and
The separation mechanism includes a holding member that holds the cleaning rotator at a first position where the cleaning rotator contacts both the fixing rotator and the cleaning pad.
When toner accumulates on the cleaning pad and the sliding resistance of the cleaning pad with respect to the cleaning rotator increases, the rotation of the fixing rotator releases the cleaning rotator from the holding state by the holding member, and the fixing rotation. Moving to a second position different from the first position in the rotation direction of the body, and the cleaning rotator is driven to rotate by the fixing rotator while the cleaning rotator and the cleaning pad are separated from each other. A fixing device characterized.

Images