JP2007226140A - Fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain separation performance of recording paper from a fixation surface while preventing staining of an output image and paper jamming at a low maintenance cost. <P>SOLUTION: A fixing device is constituted by providing a fixing body having the fixation surface and a pressing body having a pressing surface to be pressed against the fixation surface in a turnable state, and conveying the recording paper sandwitched between the fixation surface and pressing surface while fixing unfixed toner carried on a fixation-side surface of the recording paper. The fixing device is constituted by providing a separation plate 16 having a slide-contact surface 17 on which the fixation-side surface of the recording paper can slides downstream from the fixing body in a recording paper conveying direction so that the slide-contact surface faces a conveyance path for the recording paper, and separating the recording paper from the fixation surface. Here, the separation plate is provided with slide-contact surfaces on its top and reverse sides respectively and can freely be fitted so that an alternatively selected slide-contact surface faces the conveyance path. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  According to the present invention, a fixing body having a fixing surface and a pressing body having a pressing surface pressed toward the fixing surface are rotatably provided and sandwiched between the fixing surface and the pressing surface. A separating plate having a sliding contact surface on which the recording paper can be conveyed while fixing the unfixed toner carried on the fixing paper surface of the recording paper, and the fixing paper surface of the recording paper can be slidably contacted. Is provided on the downstream side of the fixing body in the recording paper conveyance direction so that the sliding surface faces the recording paper conveyance path side, so that the recording paper can be separated from the fixing surface. The present invention relates to a fixing device.

The fixing device includes a slidable contact surface on which the fixing side paper surface is slidable in order to prevent a paper jam caused by the fixing side paper surface of the recording paper portion passing through the fixing nip portion sticking to the fixing surface side. The separation plate is provided on the downstream side of the fixing member in the recording paper conveyance direction so that the sliding surface faces the recording paper conveyance path side. It is configured so that it can be separated from the fixing surface, and the fixing side paper surface of the recording paper is brought into sliding contact with the sliding surface of the separation plate. Unfixed toner tends to adhere to the sliding contact surface little by little, and the toner accumulates on the sliding contact surface over a long period of use. Or the separation performance of the recording paper from the fixing surface is reduced and paper jams are likely to occur. What the problem is.
For this reason, in the conventional fixing device, when the toner accumulates on the sliding contact surface, the entire separation plate is replaced to prevent the output image from being soiled or jammed. However, the entire separation plate is replaced. There is a problem that the maintenance cost becomes high.
Therefore, in order to solve the problem of increasing the maintenance cost, a plurality of sheets forming the sliding contact surface are laminated on a separation plate so that they can be peeled one by one, and toner accumulates on the sliding contact surface. By removing the sheet where the toner has accumulated on the sliding contact surface and exposing the sliding contact surface of the lower sheet, it is possible to remove dirt and paper jams at a low maintenance cost without replacing the separation plate. A technique for preventing the occurrence has been proposed (see, for example, Patent Document 1).

JP 2003-280440 A

However, the technology that stacks multiple sheets on a separation plate and peels off the sheet when the toner accumulates on the sliding contact surface to prevent the output image from becoming dirty or jammed is one sheet. Each time the paper is peeled off, the relative position between the sliding contact surface, the fixing surface and the pressing surface changes slightly, so that the separation performance of the recording paper from the fixing surface is lowered, and there is a possibility that paper jam is likely to occur.
The present invention has been made in view of the above circumstances, and can maintain the separation performance from the fixing surface of the recording paper while preventing the occurrence of dirt and paper jam of the output image at a low maintenance cost. The purpose is to do.

  According to a first characteristic configuration of the present invention, a fixing body including a fixing surface and a pressing body including a pressing surface pressed toward the fixing surface are rotatably provided, and the fixing surface and the pressing surface are provided. The recording paper sandwiched between the recording paper and the recording paper can be conveyed while fixing the unfixed toner carried on the fixing paper surface of the recording paper. Separating plate with a slidable surface is provided on the downstream side of the fixing body in the recording paper transport direction so that the sliding surface faces the recording paper transport path side, and the recording paper can be separated from the fixing surface. The fixing device is configured in such a manner that the sliding contact surfaces are provided on the front and back surfaces of the separation plate, and the alternatively selected sliding contact surface faces the transport path side, and the separation plate is It is in the point that it can be attached freely.

[Action and effect]
Provide a sliding surface on the front and back of the separation plate that can be slidably contacted with the recording side of the recording paper, with the sliding surface selected alternatively facing the recording paper conveyance path, and Since it is configured to be freely mounted, a separation plate is attached so that one of the sliding contact surfaces faces the recording paper conveyance path side. When toner accumulates on the sliding contact surface, the separation plate is removed to remove the toner. By attaching the separation plate so that the other sliding contact surface where no ink accumulates faces the transport path side of the recording paper, it is possible to prevent contamination of the output image and the occurrence of paper jams at low maintenance costs. Since the separation plate can be attached so that the fixing surface and the pressing surface are in a predetermined relative position, the separation performance of the recording paper from the fixing surface can be maintained.

  The second characteristic configuration of the present invention is that each of the sliding contact surfaces is formed of a material having low adhesion to the unfixed toner.

[Action and effect]
Since each of the sliding surfaces is made of a material having low adhesion to unfixed toner, the unfixed toner remaining on the fixing side paper surface is difficult to adhere to the sliding surface, and the output image is stained or jammed. Can be prevented over a long period of time.

[First Embodiment]
FIG. 1 shows a color laser printer as an example of an electrophotographic image forming apparatus provided with a fixing device A according to the present invention, and a nipping / conveying path 4 for a recording paper 3 extending between a paper feed tray 1 and a paper discharge tray 2. A fixing device A and a plurality of image transfer units B are provided.

  As shown in FIG. 2, the fixing device A includes a cylindrical fixing roller 6 as a fixing body having a fixing surface 5 formed on the outer peripheral surface, and a pressing surface elastically pressed toward the fixing surface 5. A cylindrical pressing roller 8 as a pressing body formed on the outer peripheral surface is rotatably provided, and a heater 9 is mounted on each of the inner side of the fixing roller 6 and the pressing roller 8, so that the temperature of the fixing surface 5 is increased. Is provided, a thermistor 10 for detecting the toner, a cleaning device 11 for removing unfixed toner adhering to the fixing surface 5, and a cleaning roller 12 for cleaning the pressing surface 7.

  Then, the unfixed toner held on the fixing side paper surface 13 of the recording paper 3 by the driving rotation of the fixing roller 6 with the recording paper 3 held between the fixing surface 5 and the pressing surface 7 is fixed to the fixing surface 5. And the pressing surface 7 are configured to be conveyed while being heated and fixed at a fixing nip portion 14.

  A guide member 15 for guiding the conveying posture of the recording paper 3 passing through the fixing nip portion 14 from the lower surface side is provided at the front and rear positions in the recording paper conveying direction with the pressing roller 8 interposed therebetween. When the fixing side paper surface 13 of the paper portion sticks to the fixing surface 5, a stainless steel rectangular strip-like separation plate 16 having a thickness of about 0.2 mm that can separate the recording paper 3 from the fixing surface 5. Is provided downstream of the fixing roller 6 in the recording paper conveyance direction.

  As shown in FIG. 3, the separation plate 16 includes two slidable contact surfaces 17 in the form of a rectangular strip that can be slidably contacted with the fixing side paper surface 13 of the recording paper 3 along the longitudinal direction of the separation plate 16. 4, both ends in the longitudinal direction are screwed to the mounting substrate 18 fixed to the machine frame side, and one of the sliding contact surfaces 17 faces the nipping / conveying path 4 side of the recording paper 3. It is attached as follows.

  The slidable contact surface 17 is made of two sheets 19 each having a thickness of about 0.1 mm made of a material having low adhesion to unfixed toner, for example, a fluororesin (Teflon). The other sheet 19 is placed along the other side edge of the separation plate 16 and attached to the front and back of the separation plate 16 so as to be close to the one side edge of the separation plate 16. It is provided on both front and back sides.

  Then, the insertion holes 21 of the mounting screws 20 are formed at the center in the width direction at both ends in the longitudinal direction of the separation plate 16, and the alternatively selected sliding contact surface 17 is brought close to the fixing roller 6 side, Further, the separation plate 16 is configured to be freely attached to the attachment substrate 18 so as to face the nipping / conveying path 4 side of the recording paper 3.

  The mounting substrate 18 is formed in a flat plate shape in which the reinforcing ribs 22 and the fixing tongues 23 are folded up at the side portions, and the mounting substrate 18 is a rotation that does not sandwich the recording paper 3 on the outer peripheral surface of the fixing roller 6. A pair of left and right contact portions 24 that are in contact with the non-sheet passing areas on both the left and right sides in the direction of the dynamic axis are provided, and fixed to the machine frame side so that each of the contact sections 24 contacts the non-sheet passing area. Thus, one side edge portion of the separation plate 16 fixed to the attachment substrate 18 can be attached to the fixing surface 5 at a fixed interval of about 0.1 to 1.0 mm.

[Second Embodiment]
FIG. 5 shows another embodiment of the fixing device A according to the present invention, which is attached to the front and back of the separation plate 16 so that the leading end side of the recording paper 3 that has passed through the fixing nip portion 14 is not caught by the end portion of the sheet 19. The two sheets 19 are attached to the side edges of the separation plate 16 and pasted on the front and back of the separation plate 16 so as to cover the side edges in series. 17 is provided on each of the front and back sides of the separation plate 16.
Other configurations are the same as those of the first embodiment.

[Third Embodiment]
FIG. 6 shows another embodiment of the fixing device A according to the present invention, in which one sheet 19 is separated along one side edge of the separating plate 16 and so as to cover the one side edge in a series. The two slidable contact surfaces 17 are provided on the front and back sides of the separation plate 16 so as to adhere to the front and back sides of the plate 16.
Other configurations are the same as those of the first embodiment.

[Fourth Embodiment]
FIG. 7 shows another embodiment of the fixing device A according to the present invention. A material having low adhesion to unfixed toner, for example, a fluororesin 25 is coated on both the front and back surfaces of the separation plate 16, and the separation plate 16. A sliding contact surface 17 is provided on each of the front and back sides.
Other configurations are the same as those of the first embodiment.

[Other Embodiments]
1. In the fixing device according to the present invention, a sheet formed of a material having low adhesion to unfixed toner is wound so as to cover the surface of the separation plate, and sliding surfaces are provided on the front and back surfaces of the separation plate. good.
2. In the fixing device according to the present invention, the fixing body may be constituted by an endless belt that can be driven and rotated, and the outer peripheral surface thereof may be formed on the fixing surface.
3. In the fixing device according to the present invention, the pressing body may be configured by an endless belt that can be driven and rotated, and the outer peripheral surface thereof may be formed on the pressing surface.
4). The fixing device according to the present invention may be provided in an image forming apparatus such as a copying machine or a fax machine.

Schematic side view showing the inside of the color laser printer Side view of fixing device (B) Plan view of the main part, (b) Side view of the main part (B) Plan view of the main part, (b) Side view of the main part Sectional drawing of the principal part which shows 2nd Embodiment Sectional drawing of the principal part which shows 3rd Embodiment Sectional drawing of the principal part which shows 4th Embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Recording paper 4 Conveyance path 5 Fixing surface 6 Fixing body 7 Pressing surface 8 Pressing body 13 Fixing side paper surface 17 Sliding contact surface 16 Separation plate

Claims (2)

A recording sheet sandwiched between the fixing surface and the pressing surface, wherein a fixing member having a fixing surface and a pressing member having a pressing surface pressed toward the fixing surface are rotatably provided. , Configured to be transported while fixing unfixed toner carried on the fixing side of the recording paper,
A separation plate having a slidable contact surface on which the fixing paper surface of the recording paper can slidably contact is disposed downstream of the fixing body in the recording paper transport direction so that the slidable contact surface faces the recording paper transport path side. A fixing device configured to be provided on a side and configured to be separable from the fixing surface;
A fixing device in which the sliding surface is provided on each of the front and back surfaces of the separating plate, the sliding surface selected alternatively faces the conveying path side, and the separating plate can be attached freely.   The fixing device according to claim 1, wherein each of the sliding contact surfaces is formed of a material having low adhesion to the unfixed toner.

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