JP2007093750A - Peeling board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a peeling board which is excellent in all toner non-adhesion, heat resistance, mechanical strength, and flexibility and further can be produced at low cost. <P>SOLUTION: The peeling board 1 consists of a metal plate 2 of which the surface is coated with a fluorinated polyether polymer to peel off paper from a fixing member of an electrophotographic apparatus. In the metal plate 2, the surface roughness Ra of the paper feeding side 2a with which paper is brought into contact satisfies Ra ≤1 μm, the fluorinated polyether polymer is applied at least to the surface of a portion close to the fixing member as a coat layer 3 and the fluorinated polyether polymer is a polymer having -C<SB>x</SB>F<SB>2x</SB>-O- (x is an integer of 1 to 4) as a main structure unit and has a terminal bonding with at least one polar group. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a peeling plate for peeling paper from various rollers installed in an electrophotographic apparatus such as a copying machine or a laser beam printer, and more particularly to a peeling plate for a fixing member such as a fixing roller required to have heat resistance.

  An electrophotographic apparatus such as a copying machine or a laser beam printer incorporates a fixing device for fixing toner transferred onto a sheet. An example of such a fixing device will be described with reference to FIG. FIG. 4 is a view showing a fixing device incorporating a conventional plate-like peeling member. In this fixing device, a metal heat fixing roller 10 (fixing member) having a built-in heater 9 and a pressure roller 11 having a rubber layer on the outer periphery thereof are arranged in pressure contact with each other. A sheet 13 on which the toner 12 is transferred is supplied to the sheet 13, and the toner 12 is heated to about 200 ° C. by the fixing roller 10 and is pressed by both rollers 10 and 11 to be fused to the sheet 13.

  In this fixing device, the sheet 13 may be sent out while being adhered to the outer peripheral surface of the fixing roller 10 by the toner 12 that has melted and becomes highly viscous. For this reason, normally, as shown in FIG. 4, a plate-like peeling member 14 is disposed on the paper discharge side of the apparatus so that the tip of the mother plate is close to the outer peripheral surface of the fixing roller 10. The sheet 13 is separated from the fixing roller 10 by the peeling member 14 to prevent the sheet 13 from being wound around the fixing roller 10. A plastic sheet or a metal sheet is often used for the mother plate of the plate-like peeling member 14.

When a plastic sheet is used as the base plate of the plate-like peeling member, the sheet tip tends to be plastically deformed due to contact with the outer peripheral surface of the high-temperature fixing roller, or it may be thermally expanded and deformed into a wave shape. When the paper is peeled off from the fixing roller, the paper may be caught on the deformed sheet and cause a paper jam. In addition, it is difficult to accurately process the leading end of a plastic sheet to a thickness suitable for sheet peeling, and the dimensional error may cause a paper jam.
In contrast, a metal sheet is less likely to be plastically deformed than a plastic sheet, is less deformed by thermal expansion, and is superior in terms of processing accuracy. Therefore, in the configuration shown in FIG. Can be peeled off. Conventionally, in order to prevent adhesion of toner in a melted state, a metal thin plate is used as a base material, and a release plate in which both surfaces and tip portions of the base material are coated with a fluororesin (see Patent Document 1), A release plate (see Patent Document 2) in which a fluororesin film is pasted at least on a portion of the metal plate that is in contact with or close to the fixing member via a silicone-based adhesive material is disclosed.

  However, with conventional release plates coated with fluororesin paint, etc., it is difficult to reduce the surface roughness of the coating film due to the influence of the particle size of the solid material of the coating material, and toner is deposited in minute concave portions of the coating film. There was a problem of contaminating the paper. Moreover, in the peeling board with which the conventional fluororesin film was affixed, since it was necessary to affix a film without a wrinkle, it was difficult to hold down manufacturing cost low.

On the other hand, in recent years, a fixing member such as a fixing roller, which is a mating member of a peeling plate, has become a mainstream using a soft roller whose surface or inside is a sponge.
The soft roller presses the pressure roller to form a nip portion, and the nip portion of the soft roller is elastically deformed into a concave shape. For this reason, the paper that has passed through the nip portion is peeled off from the roller even if the peeling plate is not peeled off from the roller. The peeling plate has a role of picking up the leading edge of the peeled paper and guiding it to the paper discharge passage. Since the conventional peeling member contacts the surface of the fixing roller and peels off the paper from the roller, it is necessary to process the tip of the peeling plate into a shape having no corners (for example, see Patent Document 3).
Japanese Patent Application Laid-Open No. 11-133776 JP 2001-235959 A JP 2001-83832 A

  The present invention has been made to cope with these problems, and has an object to provide a release plate having excellent toner non-adhesiveness, heat resistance, mechanical strength, flexibility, and low cost. .

The release plate of the present invention is a release plate made of a metal plate having a surface coated with a fluorinated polyether polymer, and releases the paper from the fixing member of the electrophotographic apparatus. The metal plate is in contact with the paper. The surface roughness of the sheet passing side is Ra 1 μm or less, and the fluorinated polyether polymer is coated at least on the surface in the vicinity of the fixing member.
Here, the surface roughness Ra refers to the arithmetic average roughness measured by the method defined in JIS-B0601 (2001).

The fluorinated polyether polymer is a polymer having —C _x F _2x —O— (where x is an integer of 1 to 4) as a main structural unit and terminal-bonded with at least one polar group. Features.

The fixing member is a soft roller having a foam layer inside. Further, the edge portion of the end face of the peeling plate adjacent to the fixing member is deburred.
Note that “contact with the fixing member” means that one side of the peeling plate is in line contact with the fixing roller or the like in the axial direction. “Close to the fixing member” means that there is no contact with the fixing member, and the sheet is not in contact with the roller. It means that one side of the peeling member is arranged close to the roller to such an extent that it can be prevented from being wound. The fixing member has various shapes such as a roller shape, a film shape, or a belt shape that can come into contact with the paper in a process of fixing the developer on the unfixed paper on the paper by pressurizing simultaneously with heating. Refers to a member. For example, a fixing roller or a pressure roller.

The release plate of the present invention comprises a metal plate having a surface coated with a fluorinated polyether polymer, and the metal plate has a surface roughness Ra of 1 μm or less on the paper passing side where the paper comes into contact. Since the polyether polymer is coated on at least the surface of the portion close to the fixing member, excellent toner non-adhesiveness can be obtained and the mechanical strength and flexibility are combined. Furthermore, since the coating of the fluorinated polyether polymer is very thin and has a thickness of less than 1 μm, the thickness and surface roughness of the metal plate do not change, and quality control is easy.
In addition, since the fluorinated polyether polymer is a polymer having —C _x F _2x —O— (where x is an integer of 1 to 4) as a main structural unit and terminal-bonded with at least one polar group. , Especially excellent in high temperature durability.

Since the fixing member is a soft roller having a foam layer inside, the peeling plate is not in contact with the surface of the fixing roller, and it is not necessary to process the tip of the peeling plate into a shape with no corners, so that it is easy to manufacture. It is.
Even in the case of processing, since only the deburring processing of the edge portion of the end surface close to the fixing member of the peeling plate is performed, the steps required for processing can be completed in a short time.

An example of the peeling plate of the present invention will be described with reference to FIGS. FIG. 1 is a schematic view of a fixing device using a release plate, and FIG. 2 is a partially enlarged perspective view of the release plate. The fixing device includes a heater 5a, and includes a fixing roller 5 that rotates in the direction of arrow A, a pressure roller 6 that contacts the fixing roller 5 and rotates in the direction of arrow B, and the fixing roller 5 and the pressure roller 6 The peeling plate 1 is disposed in the vicinity of the nip portion 7 formed by contact. The fixing roller 5 is a soft roller having a foam rubber layer inside.
The toner image 8a formed on the paper 8 is fixed at the nip portion 7 and becomes a fixed image 8b. The peeling plate 1 is provided at a position in contact with or close to the fixing roller 5 so that the paper 8 that has passed through the nip portion 7 can be peeled off from the fixing roller 5.

As shown in FIG. 2, the release plate 1 has one end 2 c of a metal plate 2 fixed to a support plate 4. The other end of the metal plate 2 becomes a free end 2b, and the free end 2b is arranged at a position in contact with or close to the fixing roller 5 to pick up the end portion of the paper 8 peeled off from the fixing roller 5.
The free end 2b of the metal plate does not need to be processed into an R shape and may be a cut surface. However, it is necessary to deburr in consideration of safety in handling. Further, as shown in FIG. 3 which is an enlarged view of a portion C in FIG. 2, chamfering of 0.1 mm or less may be performed.
By making the sag surface when cutting the metal plate the paper side, the deburring part can be made only on one side.

The coating layer 3 of the fluorinated polyether polymer is formed at least on the portion of the metal plate 2 through which the paper 8 passes. As a preferable covering layer forming portion, the end surface 2d of the free end 2b and the sheet passing side surface 2a with which the sheet 8 comes into contact are exemplified. By forming the coating layer 3 on the end surface 2d and the sheet passing side surface 2a, even if a developer such as toner is in a molten state and slidably contacts the release plate, it does not adhere and the paper does not become dirty.
Further, since the coating layer 3 of the fluorinated polyether polymer has a very small frictional resistance, the paper can be smoothly passed through the paper discharge path. Furthermore, since the thickness of the coating layer 3 does not increase with respect to the metal plate 2 of the base material, the metal plate 2 can be increased. As a result, the strength and flexibility of the release plate can be secured in a well-balanced manner.

  The release plate 1 has a contact width (L) that is substantially the same length as the axial length of the roller. Here, the length substantially the same as the axial length of the roller means a length at which the above effect is obtained, specifically, at least about half of the axial length of the roller, and the axial direction of the roller. It should be the same or slightly longer than the length.

As a material of the metal plate 2, iron, aluminum, copper, stainless steel or the like can be used. The plate thickness is preferably in the range of 80 to 350 μm. If it is less than 80 μm, the strength is insufficient, and it may be easily deformed during handling. If the thickness exceeds 350 μm, the flexibility of the release plate is impaired, and when the paper hits the release plate, the paper cannot be smoothly released in the paper discharge direction, which may cause rebound and cause jamming.
The surface roughness of the sheet passing side surface 2a with which the paper sheet of the metal plate 2 contacts is Ra 1 μm or less. If the surface roughness exceeds Ra 1 μm, the toner may accumulate in the recesses on the surface after the coating is formed, and the paper may be contaminated.

本発明におけるフッ素化ポリエーテル重合体はそれ自体、潤滑性、非粘着性を有する重合体であり、このような重合体を剥離板の、特に先端部に被覆しても良好な潤滑性、非粘着性を発揮する。 The fluorinated polyether polymer having at least one polar end group used in the present invention has —C _x F _2x —O— (x is an integer of 1 to 4) as a main structural unit, and a number average molecular weight of about 1000 to For example, represented by the following formulas (1) to (6).

The fluorinated polyether polymer in the present invention is itself a polymer having lubricity and non-adhesiveness. Even when such a polymer is coated on the release plate, particularly at the tip, good lubricity and non-stickiness are obtained. Demonstrate stickiness.

As a particularly preferred fluorinated polyether polymer of the present invention, a fluorinated polyether polymer having an average molecular weight of about 2000, which is commercially available as a registered trademark Fomblin Z-DISOC of Solvay Solexis, represented by the above formula (1) ,
A fluorinated polyether polymer having an average molecular weight of about 2000, which is commercially available as a registered trademark Fomblin Z-DEAL of Solvay Solexis, represented by the above formula (2);
Examples thereof include a fluorinated polyether polymer having an average molecular weight of about 2000, which is commercially available as a registered trademark Fomblin Z-DOL of Solvay Solexis, represented by the above formula (3).

The viscosity of the fluorinated polyether polymer is too high for forming a thin film of the fluorinated polyether polymer in order to give the release plate lubricity and non-adhesiveness. For example, Fomblin Z-DOL2000 has a viscosity at 20 ° C. of about 80 mm ² / sec, and Fomblin Z-DEAL2000 has a viscosity at 20 ° C. of about 20 mm ² / sec.
The fluorinated polyether polymer may be dissolved in a highly fluorinated organic solvent and coated by an appropriate method such as spraying or dipping. The dipping method is preferable because the yield of the coating liquid is very good.
The concentration of the fluorinated polyether polymer dissolved in the highly fluorinated organic solvent is not particularly limited, but considering the cost, it is preferably about 0.3 to 10% by weight. In order to obtain a particularly effective thin film, 0.5 to About 3% by weight is preferred.
Furthermore, after painting and drying, the surface is polished with a soft cloth or tissue paper, and the slightly cloudy surface is made glossy. This is to remove excess fluorinated polyether polymer.

  Since the film formed on the surface of the metal plate is very thin, it is difficult to measure the film thickness. Since the monomolecular layer of the fluorinated polyether polymer applied to the present invention is considered to be about 0.4 μm, this film is considered to be 1 μm or less even if it is a film thickness close to that. A film that is too thick will contain an excess of fluorinated polyether and consequently many free reactive end groups that are not involved in binding to the release plate matrix. This adversely affects the lubricity and non-stickiness required for the release plate of the present invention.

  The above-described method is applied to the release plate substrate, that is, the fluorinated polyether polymer is dissolved in a highly fluorinated organic solvent at an appropriate concentration, and a film is formed by an appropriate coating method such as a dipping method. Is dried at a temperature suitable for evaporating, for example, in a hot air (50 ° C.) drying oven. You may process at higher temperature after this drying, or combining drying. This high-temperature treatment after drying is a preferred treatment from the viewpoint of increasing the reactivity between the polar end groups of the fluorinated polyether and the metal plate.

  For example, this fluorinated polyether polymer-containing solution is applied to the surface of a release plate substrate made of SUS304 by dipping and heat-treated at a high temperature of 150 to 250 ° C. for an appropriate time. Here, the high temperature means a temperature at which the metal plate and the fluorinated polyether are not thermally deformed or thermally decomposed.

Examples 1 to 3
A thin metal plate (SUS304, surface roughness, Ra 0.8 μm) having a thickness of 100 μm was cut into a contact width (L) of 300 mm in length and 40 mm in width to prepare a thin metal plate serving as a peeling plate substrate. The burrs generated on the cut surface of the release plate substrate were carefully removed.
The following three fluorinated polyether polymers (number average molecular weight of 2000) were selected. That is, Fomblin Z-DISOC is used in Example 1, Fomblin Z-DEAL is used in Example 2, Fomblin Z-DOL is used in Example 3, and 1.5% by weight of each fluorinated polyether polymer is dissolved. The film was immersed in the solution (Bertrel XF manufactured by Mitsui DuPont Fluorochemical Co., Ltd.), taken out, dried at 200 ° C. for 24 hours and heat-treated, and then the functionality as a release plate was evaluated by the following evaluation method.

Functional evaluation method as release plate:
Set the release plate in the fixing section of a test copying machine (fixing temperature 190 ° C, A4 copy speed 57 sheets / min), use a line chart with an image ratio of 30% as a document, and use A4 plain paper to make 5000 sheets continuously. A copy test by passing paper was performed up to 30000 sheets. The test machine was stopped after every 5000 sheets, and the presence or absence of image quality degradation was confirmed by visual inspection of the copied paper.
As a result of the test, none of the peeling plates of Examples 1 to 3 showed any deterioration in image quality until the end of the 30000 sheet passing test. Further, no toner adhered to the release plate.

Comparative Examples 1 to 3
Except for using a thin metal plate with a surface roughness of Ra 2.5 μm, Comparative Example 1 was the same as Example 1, Comparative Example 2 was Example 2, and Comparative Example 3 was Example 3. The function of the obtained release plate was evaluated in the same manner as in Example 1.
As a result of the test, deterioration in image quality was observed at the end of the 30000 sheet passing tests for all of the peeling plates of Comparative Examples 1 to 3. Further, slight adhesion of toner was observed on the surface of the release plate.

Comparative Example 4
A metal thin plate (SUS304, surface roughness Ra 0.8 μm) was prepared in the same manner as in Example 1, and a fluorine resin was applied to the end surface 2d of the free end 2b and the sheet passing side surface 2a of the paper 8 by spray coating method as shown in FIG. A dispersed epoxy resin film was formed. The surface roughness of this coating was Ra 3.6 μm. The obtained release plate was evaluated by the same method as in Example 1.
As a result of the test, the image quality of the release plate of Comparative Example 4 was found to be degraded at the end of the 30000 sheet passing test. Further, slight adhesion of toner was observed on the surface of the release plate.

  The release plate of the present invention has excellent high-temperature durability, toner non-adhesiveness, mechanical strength and flexibility, and is low in cost. Therefore, the fixing device is used in electrophotographic apparatuses such as copying machines and laser beam printers. It can be suitably used as a peeling plate for use.

It is a schematic diagram of a fixing device using a release plate. It is a partially expanded perspective view of a peeling plate. It is the C section enlarged view in FIG. It is a figure which shows the fixing device incorporating the conventional plate-shaped peeling member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Release plate 2 Metal plate 3 Cover layer 4 Support plate 5 Fixing roller 6 Pressure roller 7 Nip part 8 Paper 9 Heater 10 Heat fixing roller 11 Heat fixing roller 12 Toner 13 Transferred paper 14 Release member

Claims (4)

A release plate that consists of a metal plate coated with a fluorinated polyether polymer on the surface, and that peels off the paper from the fixing member of the electrophotographic apparatus,
The metal plate has a surface roughness Ra of 1 μm or less on the paper passing side with which the paper contacts, and the fluorinated polyether polymer is coated on at least the surface in the vicinity of the fixing member. Characteristic release plate. The fluorinated polyether polymer is
-C _x F _2x -O- _(x is an integer from 1 to 4)
The release plate according to claim 1, which is a polymer having a main structural unit and terminal-bonded with at least one polar group.   The release plate according to claim 1, wherein the fixing member is a soft roller having a foam layer inside.   4. The peeling plate according to claim 1, wherein the edge portion of the end surface of the metal plate adjacent to the fixing member is deburred.

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