JP2011081158A - Fixing roller cleaning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing roller cleaning device that prevents image stripes Pa caused by unevenly wiping out silicon oil, or the like left on a surface of a fixing roller. <P>SOLUTION: A cleaning blade to clean the surface of the fixing roller has a mechanism that cleans the blade itself. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cleaning device that cleans the surface of a fixing roller of an image forming apparatus.

  As an example of a conventional image forming apparatus, a four-drum laser beam printer having a plurality of optical scanning units is shown in FIGS. 3 is a cross-sectional view of a conventional image forming apparatus (laser beam printer). FIG. 4 is a cross-sectional view of an image forming unit of the image forming apparatus. As shown in FIG. The four image forming stations Pa, Pb, Pc, and Pd are arranged in parallel.

  The image forming stations Pa, Pb, Pc, and Pd form magenta, cyan, yellow, and black colors, respectively, and these are image carriers that are rotated in the direction of the arrow shown in FIG. Photosensitive drums 1a, 1b, 1c, and 1d are provided.

  Further, around the photosensitive drums 1a, 1b, 1c, and 1d, the chargers 12a, 12b, 12c, and 12d, the developing devices 2a, 2b, 2c, and 2d, and the cleaners 4a, 4b, 4c, and 4d are connected to the photosensitive drums 1a, 1b, 1c, and 1d are sequentially arranged along the rotation direction, and a transfer unit 3 is provided below the photosensitive drums 1a, 1b, 1c, and 1d. The transfer unit 3 includes a transfer belt 31 serving as a recording and conveying unit common to the image forming stations Pa, Pb, Pc, and Pd and transfer chargers 3a, 3b, 3c, and 3d.

  In the printer having the above configuration, the recording paper P supplied from the paper feeding cassette 71 which is the recording material supply means shown in FIG. 3 is supported on the transfer belt 31 and conveyed to the image forming stations Pa to Pd. The toner images of the respective colors formed on the photosensitive drums 1a to 1d are sequentially transferred. When the transfer process is completed, the recording paper P is separated from the transfer belt 31 and conveyed to the fixing device 5 by the conveying belt 72 serving as recording material guiding means.

  As shown in detail in FIG. 5, the fixing device 5 includes a fixing roller 51 as a fixing rotating body excreted freely, and a pressure roller as a pressing rotating body that rotates while being pressed against the fixing roller 51. 52, a release agent application device 53 as a release agent application means, and cleaning devices 54 and 55. Heaters 56 and 57 such as halogen lamps are disposed inside the fixing roller 51 and the pressure roller 52, respectively. The thermistors 58 and 59 are disposed in contact with the fixing roller 51 and the pressure roller 52, respectively, and the voltage to the heaters 56 and 57 is controlled through a temperature adjustment circuit to fix the fixing roller 51. The temperature of the surface of the pressure roller 52 is adjusted.

  In addition, a cleaning device 54 and a release agent coating device 53 are attached to the fixing roller 51. The cleaning device 54 cleans toner and the like offset on the fixing roller 51, and the release agent coating device 53 performs cleaning. Silicone oil or the like as a release agent is applied to the fixing roller 51 to facilitate separation of the recording paper P from the fixing roller 51 and to prevent toner offset.

  The cleaning device 54 has a cleaning web 54a made of a belt-like heat-resistant non-woven fabric, a pressing roller 54b that presses the cleaning web 54a against the fixing roller 51, an unwinding roller 54c that unwinds a new cleaning web 54a, and toner. In particular, the cleaning web 54a is gradually wound around the cleaning web 54a whose cleaning ability has been lowered. In particular, the thermistor 58 is cleaned so that the offset toner adheres to the thermistor 58 to cause a detection failure. The device 54 is provided upstream of the thermistor 58 in the rotation direction of the fixing roller 51.

  By the way, as a winding method of the cleaning web 54a, there is a method of turning on a solenoid (not shown) when a predetermined number of copies are made by a counter and operating a one-way clutch to wind a predetermined amount in a direction opposite to the rotation direction of the fixing roller 51. is there. Thus, the cleaning web 54a is wound in the reverse direction so that the cleaning web 54a is not wound in the rotation direction of the fixing roller 51.

  The release agent coating device 53 is pumped up with a release agent reservoir 53a for storing a release agent such as silicone oil, and pumping rollers 53b and 53c for pumping up the release agent from the release agent reservoir 53a. An application roller 53d for applying a release agent to the fixing roller 51, a regulation blade 53e made of an elastic material such as fluororubber for regulating the amount of the release agent on the application roller 53d to a fixed amount, and the like. In particular, in order to realize uniform application of the release agent to the fixing roller 51, the release agent application device 53 is disposed downstream of the thermistor 58 in the rotation direction of the fixing roller 51.

  On the other hand, a cleaning device 55 including a cleaning web 55a, a pressing roller 55b, an unwinding roller 55c, a winding roller 55d, and the like similar to the cleaning device 54 of the fixing roller 51 is attached to the pressure roller 52. The cleaning device 55 cleans the toner adhering to the pressure roller 52 via the fixing roller 51.

  Further, a release agent removing blade 60 as a release agent removing elastic body for removing the excess release agent remaining on the pressure roller 52 is in contact with the pressure roller 52. In the case where the release agent removing blade 60 is not provided, the excess release agent accumulates in the nip between the fixing roller 51 and the pressure roller 52 and becomes a stain on the recording paper P, or the transparent film for OHP slips. As a result, poor entry into the nip occurs. Here, Si rubber, fluororubber, or the like is used as the material of the release agent removing blade 60, and the release agent removing blade 60 has an appropriate amount of entry in the forward or reverse direction with respect to the rotation direction of the pressure roller 52. Abut.

  Thus, when the recording paper P is conveyed, the fixing roller 51 and the pressure roller 52 rotate so that silicone oil as a release agent is applied to the surface of the fixing roller 51, and the recording paper P is fixed to the fixing roller 51. And the pressure roller 52 are pressed and heated from both the front and back surfaces at a substantially constant pressure and temperature, and the unfixed toner image is fixed and a full color image is formed on the recording paper P. Then, the recording paper P on which the image is fixed is separated from the pressure roller 52 by the lower separation claw 61 and discharged outside the apparatus.

JP 2006-053176

  However, in the above-described conventional example, the cleaning web 54a of the cleaning device 54 is composed of a nonwoven fabric made of amide resin fibers or polyester resin fibers for cleaning the toner or the like adhering to the fixing roller 51, and these fibers are shown in FIG. The fixing roller is cleaned by the toner T and the like being entangled by F. The cleaning web 54a needs to have a certain degree of fiber roughness in order to exhibit this cleaning capability. If the cleaning web 54a is too smooth, it becomes impossible to entangle the toner T or the like by the fiber F. For this reason, it is necessary to roughen the fibers F to some extent in order to increase the cleaning ability of the toner T and the like.

  Further, a silicone oil or the like is applied to the surface of the fixing roller 51 by a release agent coating device 53. The silicone oil or the like is transferred to the recording paper P when the recording paper P passes through the nip between the fixing roller 51 and the pressure roller 52, but a part of the silicone oil remains on the surface of the fixing roller 51.

  For this reason, the silicone oil or the like remaining on the surface of the fixing roller 51 passes through the cleaning device 54 and is wiped off by the cleaning web 54a. However, the fibers F of the cleaning web 54a are coarse, so that the wiping unevenness of the silicone oil or the like as shown in FIG. Sa is generated. (FIG. 7 is a schematic view of the fixing roller 51 as seen from above, with the cleaning paper 54a omitted.) The pressing roller 54b is made of a foamed sponge or the like, and has an uneven surface. For this reason, the cleaning web 54a cannot be pressed against the fixing roller 51 in the concave portion of the pressing roller 54b, causing the wiping unevenness Sa such as silicone oil as described above. Then, when the next recording paper P passes through the nip between the fixing roller 51 and the pressure roller 52, the wiping unevenness Sa of the silicone oil or the like remains on the surface of the fixing roller 51. The image stripe Pa as shown in FIG. 8 is generated by the wiping unevenness with the silicone oil or the like. This is because of uneven glossiness where toner images are present, or shadows when an OHP transparent film is projected, dropping image products.

  In order to solve this problem, as shown in FIG. 5, a cleaning blade 54e is disposed downstream of the cleaning web 54a in the rotation direction of the fixing roller 51, and means for uniformizing the wiping unevenness Sa such as silicon oil by the cleaning blade 54e is provided. It is considered. However, although this means has sufficient initial performance, the paper dust and residual toner that cannot pass through the cleaning web 54a and pass through the cleaning web 54a adhere to and grow on the tip of the cleaning blade 54e as the durability progresses. A minute gap is formed between the blade 54e and the fixing roller 51, and silicon oil or the like passes through the gap, and wiping unevenness Sa ′ is generated again.

  The present invention for solving the above-described problems is characterized in that a cleaning device for cleaning the surface of the fixing roller has a mechanism for cleaning the blade itself in a cleaning blade for cleaning the surface of the fixing roller.

  In the present invention, the cleaning blade for cleaning the surface of the fixing roller has a mechanism for cleaning the cleaning blade itself, so that residual toner and paper dust adhered to the cleaning blade can be cleaned, and the cleaning can be performed even if durability is advanced. The blade can always wipe off deposits such as toner remaining on the surface of the fixing roller and the silicone oil smoothly without unevenness, and can prevent the image streak Pa as shown in FIG.

1 is a cross-sectional view of a fixing device showing a first embodiment of the present invention. The expanded sectional view of the cleaning apparatus which shows the 1st Example of this invention. Sectional drawing of the image forming apparatus which shows a prior art example. Sectional drawing which shows the image forming part of a prior art example. Sectional drawing of the fixing device of a prior art example. The figure which shows the cleaning state of the cleaning web of a prior art example. The figure which shows the stripe on the fixing roller of a prior art example. The figure which shows the stripe on the recording paper of a prior art example.

  FIG. 1 is a diagram showing a first embodiment of the present invention. The fixing device 150 includes a fixing roller 151, a pressure roller 152, a release agent coating device 153, a cleaning device 154, a fixing roller 151, heaters 156 and 157 disposed inside the pressure roller 152, a fixing roller 151, The thermistors 158 and 159 are in contact with the pressure roller 152. In the present embodiment, except for the cleaning device 154, the same configuration and the same function as the conventional example are provided.

  The cleaning device 154 includes a cleaning blade 154e that evenly wipes off deposits such as residual toner on the surface of the fixing roller 151 and silicone oil, a cleaning web 154a made of a belt-like heat-resistant nonwoven fabric, and a sponge that presses the cleaning web 154a against the cleaning blade 154e. The roller 154b and the unwinding roller 154c for unwinding the new cleaning web 154a, the winding roller 154d for gradually winding the cleaning web 154a to clean the cleaning blade 154e, etc. The cleaning device 154 rotates the fixing roller 151 relative to the thermistor 158 so that offset toner does not adhere and cause a detection failure in the thermistor 158. It is provided on improving flow side.

  Here, the winding direction of the cleaning web 154a is opposite to the conventional direction and is wound in the same direction as the rotation direction of the fixing roller 151. Therefore, the cleaning web 154a is wound in the rotation direction of the fixing roller 151. A torque limiter (not shown) is installed on the shaft of the unwinding roller 154c so that it does not occur.

(Example)
FIG. 2 is an enlarged cross-sectional view of the cleaning device 154. In the first embodiment, the cleaning web 154a is made of a heat-resistant nonwoven fabric that can absorb residual oil in addition to dirt such as residual toner and paper dust, and is composed of an elastic body such as fluoro rubber and a backup member such as metal by a sponge roller 154b. 2 is adhered to the surface of the fixing roller 151, such as toner remaining on the surface of the fixing roller 151 and the silicone oil, and the like, and the tip is pressed against a cleaning blade 154e having a tapered tip.

  The cleaning web 154a is taken up by the take-up roller 154d in the direction of the arrow and sent from the take-out roller 154c. The cleaning web 154a is configured to come into contact with the tip of the cleaning blade 154e by being pressed against the cleaning blade 154e by the sponge roller 154b, and the sponge roller 154b is crushed, and the tip of the cleaning blade 154e is taken up by the take-up roller 154d. To clean.

  Further, since residual toner, paper powder, and the like melt into the residual oil blocked by the cleaning blade 154e, residual toner, paper dust, and the like are generated in the cleaning blade 154e by absorbing the residual oil with the cleaning web 154a having the above-described configuration. Reduce sticking.

  With such a configuration, it is possible to prevent residual toner, paper dust, and the like from adhering to the tip of the cleaning blade 154e, and the cleaning blade 154e always smoothes the adhesion of the residual toner and the like on the surface of the fixing roller 151 and silicone oil, etc. evenly. It is possible to wipe it off.

  In the second embodiment, in the cleaning device 154 having the same configuration as that of the first embodiment shown in FIG. When the rotation is stopped, a solenoid (not shown) is turned on, and a one-way clutch (not shown) is operated to rotate the take-up roller 154d and take up in the same direction as the fixing roller 151. By such a winding sequence of the cleaning web 154a, it is possible to prevent the cleaning blade 154e from being left and fixed with the residual toner or paper dust wiped off from the surface of the fixing roller 151 on the tip of the cleaning blade 154e. It is possible to always wipe off the deposits such as residual toner on the surface of the fixing roller 151 and the silicone oil smoothly without unevenness.

Claims (3)

  A cleaning device for cleaning a surface of a fixing roller, wherein the cleaning blade for cleaning the surface of the fixing roller has a mechanism for cleaning the cleaning blade itself.   2. The cleaning apparatus according to claim 1, wherein a cleaning web capable of absorbing residual oil in addition to dirt such as residual toner and paper dust is pressed against the cleaning blade with a sponge roller as cleaning means for the cleaning blade.   The winding of the cleaning web has a sequence of winding the cleaning web quantitatively simultaneously with the start of rotation of the fixing roller, and winding the cleaning web by stopping several millimeters after stopping the fixing roller. Cleaning device.

Images