JP5400497B2 - Sheet-like peeling member for electrophotographic apparatus and electrophotographic apparatus - Google Patents

Description

  The present invention relates to a sheet-like peeling member for peeling a sheet from a fixing member such as a fixing roller and a fixing belt incorporated in an electrophotographic apparatus such as a copying machine or a laser printer, and an electrophotographic apparatus using the same.

  In an electrophotographic apparatus such as a copying machine or a laser printer, an electrostatic latent image formed on a photosensitive drum is developed on a sheet using a developer such as toner, and then the developer transferred to the sheet is fixed to a fixing roller. In addition, there is a fixing unit that is heated and melted by a fixing member such as a fixing belt or the like and is fixed to a sheet by applying pressure. In many cases, the fixing unit is provided with a sheet-like peeling member for smoothly peeling the paper on which the developer is fixed from the fixing member.

  The sheet-like peeling member peels the sheet from the fixing member by bringing the leading end of the sheet-like base material into contact with or close to the fixing member. Here, the contact means that one side of the front side of the sheet-like base material is in line contact with the fixing member in the axial direction thereof, and the proximity means that the base material can be prevented from being wound around the fixing member. This means that one side of the front end side is located close to the fixing member. As such a peeling member, in order to improve the paper peelability and prevent the paper from being soiled due to toner adhesion, an increasing number of the peeling members are covered with a fluororesin.

  Examples of the sheet-like release member that covers the tip of the substrate with a fluororesin include, for example, a fluororesin film attached to a substrate with a silicone-based adhesive (see Patent Document 1), and the substrate surface is coated with a fluororesin And a coating film is formed (see Patent Document 2).

JP 2001-235959 A JP 2003-248393 A

  However, in the sheet-like peeling member described in Patent Document 1, when the fixing member becomes a high temperature of 200 ° C. or more with an increase in printing speed, the adhesive strength of the silicone-based adhesive is reduced, and the fluororesin film becomes There is a risk of peeling.

  Further, in the sheet-like peeling member of Patent Document 2, the fluororesin coating film is worn by sliding with the fixing member or the paper, so that the paper may be difficult to peel off or the toner may be easily attached. In particular, in the case of using a color toner having high adhesiveness in recent years, there is a problem that the toner is more easily attached and the paper is contaminated.

  The present invention has been made in order to cope with such a problem, and is a sheet-like peeling member that can be used even under high temperature conditions and can maintain excellent paper peeling properties over a long period of time, and an electrophotographic apparatus using this sheet peeling member The purpose is to provide.

  The sheet-like peeling member of the electrophotographic apparatus of the present invention is the above sheet-like peeling member in the sheet-like peeling member that peels the sheet from the fixing member by bringing the leading end portion of the sheet-like substrate into contact with or close to the fixing member of the electrophotographic apparatus. A resin film containing a spherical filler is formed on the surface of the base material on the side through which the paper passes (sheet passing side surface). Here, the spherical shape refers to a spherical shape having a ratio of the minor axis to the major axis of 0.8 to 1.0.

  The resin coating is a resin coating, and the spherical filler has a larger particle size than the thickness of the resin component in the resin coating. The film thickness of the resin component of the resin coating film is 5 to 35 μm.

The spherical filler is a spherical filler having a particle diameter of 50 μm to 500 μm. The spherical filler is contained in 30 to 1800 per 1 cm ² of the resin coating.

  The spherical filler is a hollow filler or a particulate filler. The hollow filler is any one of a resin balloon, a ceramic balloon, a shirasu balloon, or a glass balloon. Further, the particulate filler is any of resin beads, ceramic beads, silica beads, glass beads, or carbon beads.

  The thickness direction of the front-end | tip part of the said sheet-like base material is made into the curved surface, It is characterized by the above-mentioned. In the resin coating, the spherical filler is not included in the portion formed at the tip of the sheet-like base material. Further, the surface opposite to the surface through which the sheet of the sheet-like base material passes (reverse paper passing surface) is a smooth surface.

  The resin coating film has a fluorine-containing polymer as a main component. The fluorine-containing polymer is a polytetrafluoroethylene (hereinafter referred to as PTFE) polymer, a tetrafluoroethylene-perfluoroalkyl vinyl ether (hereinafter referred to as PFA) copolymer, and a tetrafluoroethylene-hexafluoropropylene ( (Hereinafter referred to as FEP).

  The electrophotographic apparatus of the present invention is an electrophotographic apparatus having a sheet-like peeling member for peeling off the sheet on which the developer is fixed from the fixing member, and is characterized by using the sheet-like peeling member of the present invention. The electrophotographic apparatus is a full-color electrophotographic apparatus using color toner.

  Since the sheet-like release member of the present invention (Claim 1) has a structure in which a resin film in which a spherical filler is blended is formed on the sheet-passing side surface of the sheet-like base material as described above, Small contact area and excellent low friction characteristics with paper. Moreover, since the heat dissipation of a sheet-like base material becomes high with a spherical filler, it can prevent that a sheet-like peeling member becomes high temperature, and the sheet | seat peelability excellent over the long term is maintained.

  In the sheet-like release member according to claim 2, since the resin coating formed on the sheet passing side surface of the sheet-like base material is a resin coating, a spherical filler can be easily contained in the resin coating. It is.

  In the sheet-like release member according to claim 3, since the particle diameter of the spherical filler is larger than the film thickness of the resin component in the resin coating film formed on the sheet passing side surface of the sheet-like base material, The spherical filler is formed so as to protrude from the film, and the irregularity of the spherical filler is formed on the surface of the sheet-like substrate, so that the heat dissipation of the sheet-like substrate is enhanced. Further, the contact area with the paper is small, and the low friction characteristic with the paper is excellent.

  In the sheet-like release member according to claim 4, since the film thickness of the resin component of the resin coating film is 5 μm to 35 μm, the retention of the spherical filler is good, and in particular, the particle diameter of the spherical filler is 50 μm to 500 μm. If it exists (Claim 5), since the unevenness | corrugation of a spherical filler is clearly formed in the sheet-like base material surface, the sheet-like peeling member which is excellent in the low friction characteristic and the heat dissipation effect can be obtained.

In the sheet-like release member according to claim 6, since 30 to 1800 spherical fillers contained in the resin coating are contained per 1 cm ^{2 of the} resin coating, the uneven portions of the spherical filler formed on the surface of the sheet-like substrate. The sheet is not caught on the sheet, and an effect of excellent sheet guide property is obtained.

  In the sheet-like release member according to claim 7, since the spherical filler contained in the resin film is a hollow filler or a particulate filler, in the case of a hollow filler, the heat dissipation effect is excellent. In the case of a particulate filler, the durability is excellent.

  Since the thickness direction of the front-end | tip part of a sheet-like base material is made into a curved surface, the sheet-like peeling member of Claim 10 will be in the pressure contact state more than fixed pressure with respect to fixing members, such as a fixing roller and a fixing belt. Even in the case of damage, the surface of the fixing member is not damaged.

  Since the sheet-like peeling member according to claim 11 does not include a spherical filler in a portion formed at the tip portion of the sheet-like base material in the resin film, the horizontal accuracy of the tip portion can be maintained high.

  Since the sheet-like peeling member according to claim 12 makes the sheet passing surface of the sheet-like base material a smooth surface, accuracy deterioration does not occur in integration with the support member.

  The sheet-like release member according to claim 13 is excellent in releasability with respect to the toner since the coating film mainly containing the fluoropolymer is formed on the surface of the sheet-like substrate.

  The sheet-like release member according to claim 14, wherein the fluoropolymer is any one of a PTFE polymer, a PFA copolymer, and an FEP copolymer. Releasability can be maintained.

  The electrophotographic apparatus according to the present invention (Claim 15) uses the above-described sheet-like release member as a release member for releasing the paper on which the developer is fixed from a fixing member such as a fixing roller or a fixing belt. It becomes an electrophotographic apparatus having excellent properties.

  The electrophotographic apparatus according to claim 16 can be suitably used as a full-color electrophotographic apparatus because the sheet-like release member is excellent in releasability from highly adhesive color toner.

It is a schematic diagram of a fixing device using a sheet-like release member. 2A is a perspective view showing an example of a sheet-like peeling member, FIG. 2B is an enlarged front view of a portion C in FIG. 2A, and FIG. 2C is a D- in FIG. 2B. It is the partial expanded sectional view cut | disconnected by D line.

  An example of the sheet-like peeling member and electrophotographic apparatus of the present invention will be described with reference to FIG. FIG. 1 is a schematic view of a fixing device using a sheet-like peeling member. As shown in FIG. 1, the fixing device includes a heater 5 a, 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 a fixing roller. 5 and the sheet-like peeling member 1 disposed in the vicinity of the nip portion 7 formed by contact with the pressure roller 6. The fixing roller 5 is a soft roller having a foam rubber layer inside. The toner image formed on the paper 8 is fixed at the nip portion 7 and becomes a fixed image. The sheet-like peeling member 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.

  The sheet-like peeling member 1 will be described in detail with reference to FIG. 2A is a perspective view showing an example of a sheet-like peeling member, FIG. 2B is an enlarged front view of a portion C in FIG. 2A, and FIG. 2C is FIG. It is a partially expanded sectional view cut | disconnected by the DD line | wire of FIG. As shown in FIGS. 2A and 2C, the sheet-like release member 1 includes a metal support member 3 having an attachment portion 4, a sheet-like substrate 2 made of a thin metal plate, and a release layer. And a resin coating 2d. The resin coating 2d includes a spherical filler 2c. In the sheet-like substrate 2, the side opposite to the side fixed to the support member 3 is the surface (sheet passing side surface) through which the sheet passes, and the resin coating 2d is formed on the sheet passing side surface. Yes.

  One end (fixed end) 2b of the sheet-like substrate 2 is fixed to the support member 3 with an adhesive or welding. The other end of the sheet-like substrate 2 becomes a free end (tip) 2a, and the free end 2a 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. Take (see FIG. 1).

  The support member 3 is made of metal, and the sheet-like substrate 2 may be made of metal, synthetic resin, or ceramic, but is made of metal such as spring alloy, copper alloy such as stainless steel or brass, or aluminum alloy. It is preferable if it is easy to process and inexpensive.

  The sheet thickness of the sheet-like substrate 2 is preferably in the range of 60 to 500 μm. If the thickness is less than 60 μm, the strength is insufficient, and there is a possibility of being easily deformed during handling. If the thickness exceeds 500 μm, the flexibility of the sheet-like peeling member 1 is impaired, and when the paper hits the sheet-like peeling member 1, the paper cannot be smoothly discharged in the paper discharge direction, causing rebound and causing jamming. There is a risk.

  It is preferable that the surface opposite to the surface through which the sheet of the sheet-like substrate 2 passes (the anti-sheet passing surface) is a smooth surface. Since the sheet-like substrate 2 is integrated with the metal support member 3 by an adhesive or welding, when the back surface of the sheet-like substrate 2 is a smooth surface, the sheet-like substrate 2 is integrated with the support member 3 by an adhesive or welding. Adhesiveness is improved, and the horizontal accuracy of the tip is not particularly deteriorated.

  The sheet-like substrate 2 has a contact width that is substantially the same as the axial length of the fixing roller 5. Here, the length substantially the same as the axial length of the fixing roller is at least about half or more of the axial length of the fixing roller, and may be the same as or slightly longer than the axial length of the fixing roller.

  The resin coating 2d is preferably a resin coating formed by applying a resin coating composition containing a spherical filler 2c to the sheet-passing side surface of the sheet-like substrate 2. By setting it as a coating film, the spherical filler 2c can be easily contained in the resin coating 2d. The resin coating 2d is preferably a resin coating containing a fluoropolymer as a main component in order to improve the releasability of the sheet-like release member 1 with respect to the toner. In particular, by using any one of PTFE polymer, PFA copolymer and FEP copolymer as the fluoropolymer, the releasability with respect to the toner can be maintained for a long time. Moreover, in this invention, since it is excellent in the heat dissipation of the sheet-like base material 2, the physical-property deterioration of the resin film which has a fluoropolymer as a main component is also suppressed.

  As a method of obtaining a resin coating composition for obtaining a resin coating film containing a fluoropolymer as a main component, (1) a spherical filler is applied to a resin varnish obtained by dispersing a fluoropolymer powder in a resin solvent. A method of blending and stirring uniformly, and a method of (2) blending a fluoropolymer powder and a spherical filler in a resin solvent and stirring uniformly are mentioned. Further, in order to prevent a decrease in paper peelability due to static electricity, it is preferable to blend carbon fine powders such as ketjen black and acetylene black into the resin coating composition. Various methods such as a dipping method, a roller coating method, a brush coating method, a spray coating method, and a printing coating method can be adopted as a method for applying the resin coating composition to the sheet passing side surface of the sheet-like substrate 2. .

  In order to keep the horizontal accuracy of the tip 2e of the sheet-like substrate 2 high, it is preferable that the portion formed on the tip 2e in the resin coating 2d does not include the spherical filler 2c. In order to form in this way, a resin film not containing the spherical filler 2c is formed in advance on the tip 2e, and after covering this part with masking or the like, the resin containing the spherical filler 2c on the paper passing side surface It can be performed by a method such as forming a film. Note that the front end portion of the sheet-like base material is a portion that is in contact with or close to the fixing member of the electrophotographic apparatus, and is within a range of about 1 mm to 3 mm from the front end that is in contact with the fixing member in the sheet-like base material. is there.

  The film thickness of the resin component of the resin coating 2d that is a coating film is preferably 5 μm to 35 μm. If the film thickness of the resin component of the resin coating 2d is less than 5 μm, the retention of the spherical filler 2c is poor, and the spherical filler 2c falls off. If it is thicker than 35 μm, there is a possibility that defects such as cracks and discharges may occur in the step of forming the resin coating 2d, which is not preferable.

  The particle diameter of the spherical filler 2c is preferably 50 μm to 500 μm. If the particle diameter of the spherical filler 2c is smaller than 50 μm, the heat dissipation effect cannot be expected, and if it is larger than 500 μm, the sheet guide property is lowered.

  It is preferable to make the particle diameter of the spherical filler 2c larger than the film thickness of the resin component in the resin coating 2d. By making the particle diameter of the spherical filler 2c larger than the film thickness of the resin component in the resin coating 2d, the spherical filler 2c is formed so as to protrude from the resin coating 2d, and the spherical filler is formed on the surface of the sheet-like substrate 2 When the unevenness of 2c is clearly formed, the heat dissipation of the sheet-like substrate 2 is increased (see FIG. 2C). Further, the contact area with the paper is small, and the low friction characteristic with the paper is excellent. Even when a resin spherical filler is used, the resin spherical filler does not correspond to the resin component in the resin coating (coating film).

It is preferable to contain 30 to 1800 spherical fillers 2c in the resin coating 2d per 1 cm ² of the resin coating. If the number of the spherical fillers 2c is less than 30 per 1 cm ^{2 of the} resin coating, the sheet guiding property may be deteriorated.

  The spherical filler 2c is preferably a hollow filler or a particulate filler. By using the hollow filler, the heat dissipation effect of the resin coating 2d can be improved, and by using the particulate filler, the durability of the resin coating 2d can be improved. The hollow filler is preferably a resin balloon, ceramic balloon, shirasu balloon or glass balloon, and the particulate filler is preferably resin beads, ceramic beads, silica beads, glass beads or carbon beads. These spherical fillers are preferable because they have an excellent heat dissipation effect, can be manufactured with the above-mentioned particle diameter of 50 μm to 500 μm, and are inexpensive.

  It is preferable to make the thickness direction of the front-end | tip part 2e of the sheet-like base material 2 into a curved surface without an edge (refer FIG.2 (c)). By making the thickness direction of the tip part a curved surface, the surface of the fixing member is not damaged even when the pressure member is in a pressure contact state higher than a constant pressure with respect to a fixing member such as a fixing roller or a fixing belt. The curved surface may be machined after the metal sheet-like base material 2 is processed into a predetermined shape, but it is desirable to process by a press cut that can be pressure-formed simultaneously with cutting. The edge on the pressing direction side of the front end portion 2e is formed into an R shape by press sag by press cutting, and the edge on the anti-pressing direction side presses a press plate inclined by 45 ° with respect to the substrate surface in order to prevent generation of minute burrs. Thus, a chamfered portion can be formed, and the distal end portion 2e can be a curved surface. Further, in the metal sheet-like base material, the shape in the thickness direction of the tip portion may be set such that the sagging surface at the time of cutting is set to the paper side, and deburring is performed only on one side.

  In a full-color electrophotographic apparatus, a polyester-based binder resin having high transparency is used as a binder (binding) resin that is one of the constituent elements of color toner in order to improve color developability. This resin is very sticky. The sheet-like release member of the present invention forms such a color toner by forming on the surface of the sheet-like base material the paper passing side by forming a resin coating film mainly composed of a fluoropolymer compounded with a spherical filler. Can be suitably used for a full-color electrophotographic apparatus.

  Since the sheet-like release member of the electrophotographic apparatus of the present invention has a structure in which a resin film in which a spherical filler is blended is formed on the paper passing side surface, the contact area with the paper is small, and the low friction characteristic with the paper and Excellent heat dissipation. For this reason, the fixing member can be suitably used as a sheet-like peeling member of a high-speed, full-color electrophotographic apparatus that is used under conditions where the fixing member has a high temperature of 200 ° C. or higher.

DESCRIPTION OF SYMBOLS 1 Sheet-like peeling member 2 Sheet-like base material 2a Free end (tip)
2b Fixed end 2c Spherical filler 2d Resin coating (coating)
2e Tip part 3 Support member 4 Mounting part 5 Fixing roller 6 Pressure roller 7 Nip part 8 Paper

Claims (15)

In the sheet-like peeling member that peels the sheet from the fixing member by bringing the leading end of the sheet-like base material into contact with or close to the fixing member of the electrophotographic apparatus,
A resin film containing a spherical filler is formed on the surface of the sheet-like base material on which the paper passes ,
The sheet-like release member of an electrophotographic apparatus, wherein the resin coating does not include the spherical filler in a portion formed at a tip portion of the sheet-like base material .   The sheet-like release member of an electrophotographic apparatus according to claim 1, wherein the resin coating is a resin coating.   3. The sheet-like release member for an electrophotographic apparatus according to claim 2, wherein the spherical filler has a larger particle diameter than the film thickness of the resin component in the resin coating film.   4. The sheet-like release member for an electrophotographic apparatus according to claim 2, wherein the resin component of the resin coating film has a thickness of 5 to 35 [mu] m.   The sheet-like release member for an electrophotographic apparatus according to any one of claims 1 to 4, wherein the spherical filler is a spherical filler having a particle diameter of 50 µm to 500 µm. 6. The sheet-like release member for an electrophotographic apparatus according to claim 1, wherein 30 to 1800 spherical fillers are contained per 1 cm ^{2 of the} resin coating.   The sheet-like peeling member for an electrophotographic apparatus according to any one of claims 1 to 6, wherein the spherical filler is a hollow filler or a particulate filler.   8. The sheet-like peeling member for an electrophotographic apparatus according to claim 7, wherein the hollow filler is any one of a resin balloon, a ceramic balloon, a shirasu balloon, and a glass balloon.   8. The sheet-like release member for an electrophotographic apparatus according to claim 7, wherein the particulate filler is any one of resin beads, ceramic beads, silica beads, glass beads, and carbon beads.   The sheet-like peeling member of an electrophotographic apparatus according to any one of claims 1 to 9, wherein a thickness direction of a tip portion of the sheet-like substrate is a curved surface. The sheet-like peeling member of an electrophotographic apparatus according to any one of claims 1 to 10 , wherein the surface of the sheet-like substrate opposite to the surface through which the paper passes is a smooth surface. The sheet-like release member of an electrophotographic apparatus according to any one of claims 2 to 11 , wherein the resin coating film contains a fluoropolymer as a main component. The fluoropolymer is any one of a polytetrafluoroethylene polymer, a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and a tetrafluoroethylene-hexafluoropropylene copolymer. 12. A sheet-like peeling member for an electrophotographic apparatus according to 12 . A electrophotographic apparatus having a sheet-like peeling member for peeling the sheet on which the developer has been fixed from fixing member, the sheet separation member is a sheet-like according to one of claims 1 to 13 An electrophotographic apparatus which is a peeling member. The electrophotographic apparatus according to claim 14 , wherein the electrophotographic apparatus is a full color electrophotographic apparatus using color toner.

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