JP2019105671A - Elastic roller and image forming apparatus - Google Patents

Abstract

To provide a fixing roller that can more stably operate an image forming apparatus.SOLUTION: The present invention provides a fixing roller that comprises at least a shaft body, and a porous elastic layer formed on an outer peripheral surface of the shaft body, wherein when an angle formed by the shaft body and a major axis of a single hole included in the elastic layer is β, the relative frequency of holes having β of 0° or more and less than 90° is C, and the relative frequency of holes having β of 90° or more and 180° or less is C, the difference between Cin an area of the elastic layer of 10% from one end 0% of the elastic layer and 33% from a surface layer 0% and Cin an area of the elastic layer of 10% from the other end 0% of the elastic layer and 33% from the surface layer 0% is more than 0% and 15% or less.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an elastic roller which is less likely to shift the relative position of an endless belt during operation of an image forming apparatus, and an image forming apparatus using the same.

  Various image forming apparatuses using an electrophotographic system are adopted for printers such as laser printers and video printers, copying machines, facsimiles, and multifunction machines thereof. An image forming apparatus using an electrophotographic method includes various rollers. For example, a charging roller that uniformly charges an image carrier such as a photosensitive member, a developing roller that carries and transports a developer and supplies the developer to the image carrier, and a developer supply roller that charges the developer while charging the developer. Examples include a cleaning roller that receives foreign particles remaining or adhering to the surface of the image carrier in contact with or in pressure contact with the image carrier, a fixing roller that fixes a developer image transferred to a recording medium such as recording paper, and the like. Since these various rollers affect the quality of the image formed by the image forming apparatus, various investigations have been made regarding the layer configuration of the roller, additives to be contained in each layer, and the like.

  Generally, when manufacturing a fixing roller, a foaming agent is mixed in silicone rubber, and the silicone rubber in which these are mixed is extruded using a mold or the like, and heat treatment is performed to foam the foaming agent. Thus, a porous elastic layer is formed (see, for example, Patent Document 1).

JP 2005-055680 A

  Here, in general, the fixing roller is driven through the endless belt and abuts on and interlocks with the pressure roller, but when the endless belt rotates, the endless belt is unidirectional due to the characteristics of the image forming apparatus. The phenomenon of moving to is confirmed. When the endless belt moves in one direction during operation of the image forming apparatus, and the relative position between the fixing roller or the pressure roller and the endless belt is deviated, the stable operation of the image forming apparatus is disturbed. Were concerned. Therefore, the present invention has been made in view of the above problems, and the relative position between the fixing roller or the pressure roller and the endless belt is less likely to occur, and the image forming apparatus is more stable than in the prior art. It is an object of the present invention to provide an elastic roller which can be driven as well as an image forming apparatus using the same.

  The inventors of the present invention conducted intensive studies in view of the above problems. As a result, due to the convection of the silicone rubber that occurs when the fixing roller and the pressure roller are extrusion molded, and the uneven heat conduction during the heat treatment, particularly from the foaming agent in the surface layer and the end portion of the molded body It has been found that the longitudinal direction of the formed hole is biased in one direction from the direction perpendicular to the shaft. Here, when the condition for cutting out the molded product and the polishing condition are adjusted so that the inclination of the hole in the major axis direction is asymmetric at the end of the elastic layer, when driving the fixing roller or the pressure roller, It was found that a force in a certain direction acts on the surface. The inventors have found that the above-mentioned problems can be solved by opposing the force acting on the surface layer and the force of the endless belt moving in the axial direction, and the present invention has been completed. Specifically, the present invention provides the following.

(1) An elastic roller having at least a shaft and a porous elastic layer formed on the outer peripheral surface of the shaft, wherein the long axis of a single hole contained in the elastic layer and the shaft are _Assuming that the angle formed is β, and the appearance ratio of pores where β is 0 ° or more and less than 90 ° is C _0-90, and the appearance ratio of holes where β is 90 ° or more and 180 ° or less is C _90-180 , C _0-90 in the elastic layer in the region of 0% to 10% of one end of the elastic layer and 0% to 33% of the surface layer, 0% to 10% of the other end of the elastic layer, and 0% to 33% of the surface layer An elastic roller, wherein the difference between C _90-180 in the elastic layer in the area of is greater than 0% and not more than 15%.

(2) C _0-90 is 45% or more and 55% or less, and C _90-180 is 45% in the elastic layer in the region of 10% in the axial center of the elastic layer and 0% to 33% of the surface layer The elastic roller according to (1), which is 55% or less.

  (3) The elastic roller as described in (1) or (2) whose hole diameter of the hole contained in an elastic layer is 30 micrometers or more and 300 micrometers or less.

  (4) The elastic roller in any one of (1) to (3) whose thickness of an elastic layer is 1 mm or more and 50 mm or less.

  (5) An image forming apparatus comprising the elastic roller according to any one of (1) to (4) as a fixing roller or a pressure roller.

  According to the present invention, under the manufacturing conditions of the fixing roller and the pressure roller, the long axis of the hole contained in the elastic layer analyzes the angle β formed with the shaft individually, and β is 0 ° or more and less than 90 °. Since the cutout condition of the elastic layer is adjusted so that the appearance ratio of the holes becomes asymmetric at the end of the elastic layer, the unsupporting belt moves in one axial direction the force acting on the surface of the elastic roller It is possible to counteract the force to move, and in the image forming apparatus, the elastic roller can be stably driven.

It is drawing which shows the schematic diagram of the hole contained in an elastic layer. It is drawing which shows an example of the elastic roller of this invention. FIG. 1 is a schematic view showing an example of an image forming apparatus of the present invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

<Elastic roller>
The elastic roller 1 of the present invention has a shaft body 2, an elastic layer 3 and a releasing layer 4 as shown in FIG.

[Shaft]
The shaft 2 may be the same as the shaft used in a conventionally known elastic roller. The shaft 2 is a shaft called "core metal" made of iron, aluminum, stainless steel, brass or the like. The shaft 2 may be a shaft obtained by plating an insulating core such as a thermoplastic resin or a thermosetting resin.

[Elastic layer]
(Distribution in the direction of the long axis of the hole)
The elastic roller 1 of the present invention, as shown in FIG. 1, has an angle formed by the major axis (I in FIG. 1) of the single hole contained in the elastic layer 3 and the shaft 2 (X in FIG. 1). When it is assumed that the appearance rate of pores where β is 0 ° or more and less than 90 ° is C _0-90 and the appearance rate of holes where β is 90 ° or more and 180 ° or less is C _90-180 , elastic layer 3 C _0-90 in the elastic layer 3 in the region of 0% to 10% of one end and 0% to 33% of the surface layer, and 0% to 10% of the other end of the elastic layer 3 and 0% to 33% of the surface layer It is _preferable that the difference between the elastic layer 3 and the C _{90 -180} in the region of (1) is more than 0% and 15% or less, and is 1% or more and 9% or less. That is, in the elastic roller 1 according to the present invention, the inclination of the holes is distributed at the one end and the other end of the elastic layer 3 with respect to the direction separated from the direction perpendicular to the shaft 2. However, the degree of deviation of the inclination of the hole from the direction perpendicular to the shaft body 2 is different to a certain extent at both the left and right ends. Thus, when the distribution of the inclination of the holes is asymmetrical at the left and right ends of the elastic layer 3, a force acts in one direction when the elastic roller 1 is operated, and this causes the endless belt to move in the axial direction. By opposing the force to move to, the relative position of the endless belt does not shift in the axial direction of the elastic roller 1, and the elastic roller 1 can be operated stably. In the present invention, the axial center 10% of the elastic layer 3, and the elastic layer 3 of 33% in the region from the surface layer _{0%, C 0-90} is not more than 45% more than _{55%, C 90} It is preferable that _-180 is 45% or more and 55% or less.

In order to adjust the distribution of the direction of the long axis of the holes in the elastic layer 3, for example, using a tester "PORE! SCAN" (trade name, manufactured by Hiraizumi Yoko Co., Ltd.) for polyurethane foam elastomer, under predetermined conditions The distribution of the long axis of the holes in the elastic layer 3 manufactured in the above is confirmed for each portion of the elastic layer 3 so that C _0-90 and C _90-180 in a predetermined region satisfy the above conditions. It is preferable to adjust by adjusting the cut amount of the both ends of the elastic layer 3 after shaping | molding, and the grinding amount of the surface. Here, with respect to the distribution in the direction of the long axis of the holes in the elastic layer 3, the diameter of the elastic layer to be formed, the size of the mold, the characteristics of various materials used for forming the elastic layer 3, the heating conditions at the time of heat molding, etc. In measuring the distribution in the direction of the long axis of the hole by “PORE! SCAN”, it is preferable to measure these conditions in agreement with the actual manufacturing conditions.

  The hole diameter of the holes contained in the elastic layer of the elastic roller 1 of the present invention is preferably about 30 μm to 300 μm, and more preferably 50 μm to 250 μm. .

(Thickness of elastic layer)
Elastic roller of the present invention, as C _0-90, and C _90-180 becomes a predetermined numerical value, since the polished outer while cutting the both end portions, the thickness of the elastic layer 3 is usually It is preferably 1 mm or more and 60 mm or less, and more preferably 2 mm or more and 30 mm or less.

(Foam rubber composition)
The elastic layer 3 can be produced by heating and curing a foamed rubber composition. As the foamed rubber composition, a composition containing a rubber, a foaming agent, and, if necessary, various additives and the like can be suitably used. Although various rubbers can be adopted as the rubber, among them, silicone rubber is preferable. As a foamed rubber composition containing silicone rubber, it contains a vinyl group-containing silicone raw rubber, a silica-based filler, a foaming agent, an addition reaction crosslinking agent, an addition reaction catalyst, and a reaction control agent, as required Further, an addition reaction type foamed silicone rubber composition containing an organic peroxide crosslinking agent, a heat resistance improver and various additives is preferable. As such an addition reaction type foaming silicone rubber composition, the addition reaction type foaming silicone rubber composition indicated, for example in JP, 2008-076751, A is mentioned.

  Here, the foaming agent is not particularly limited, and known silicone rubber foaming agents can be used. As the foaming agent, for example, organic azo foaming agents such as azobisisobutyronitrile (AIBN), azodicarbonamide (ADCA), dinitrosopentamethylenetetramine (DPT), hydrazodicarbonamide (HDCA) and the like are suitably used. be able to.

  The compounding quantity of a foaming agent can be suitably changed according to the foaming ratio of a foam. The expansion ratio of the foam may be, for example, 110% or more, and may be 500% or less or 350% or less. The blending amount of the foaming agent may be an amount that can achieve such a foaming ratio.

(Release layer)
A release layer 4 is provided on the outer peripheral surface of the elastic layer 3. The release layer 4 is a layer intended to improve the releasability of the toner and the fixing roller 1 and to prevent the toner from adhering.

  As the release layer 4, for example, a layer containing a fluorine resin can be mentioned. As the fluorine resin, for example, fluorinated ethylene-propylene copolymer (FEP), fluorinated ethylene-perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer (ETFE), Polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE) and the like can be mentioned.

  The thickness of the release layer 4 is not particularly limited, and may be, for example, 15 μm to 150 μm, or 20 μm to 100 μm.

  The release layer 4 may be formed by applying a coating solution containing a fluorine resin on the elastic layer 3. The release layer 4 may be formed of a tube containing a fluorocarbon resin, and may be formed by covering the outer peripheral surface of the elastic layer 3 with the tube.

  A primer layer may be provided between the elastic layer 3 and the release layer 4 to bond the two. The primer layer may be a layer containing an adhesive or its cured product. As an adhesive agent, a silicone type adhesive agent, an acrylic type adhesive agent, etc. can be used, for example. The thickness of the adhesive layer is not particularly limited, and may be, for example, 1 μm to 100 μm, or 5 μm to 50 μm.

<Method of manufacturing elastic roller>
The elastic roller 1 is manufactured by forming the elastic layer 3 on the outer peripheral surface of the shaft body 2 and further forming the releasing layer 4 on the outer peripheral surface of the elastic layer 3.

  In order to manufacture the elastic roller 1, first, the shaft 2 is prepared. For example, the shaft 2 is prepared in a desired shape by a known method. The shaft 2 may be coated with a primer before the elastic layer 3 is formed. The primer to be applied to the shaft 2 is not particularly limited, and the same resin and crosslinking agent as materials for forming the primer layer for adhering or adhering the elastic layer 3 and the release layer 4 may be mentioned. The primer is, if desired, dissolved in a solvent or the like, and applied to the outer peripheral surface of the shaft according to a standard method, for example, a dip method, a spray method or the like.

  The elastic layer 3 is formed by heat-curing the foamed rubber composition on the outer peripheral surface of the shaft 2. For example, the elastic layer 3 is formed on the outer peripheral surface of the shaft 2 by performing heat curing and molding simultaneously or continuously by a known molding method. The method of curing the foamed rubber composition may be any method as long as the heat necessary for curing the foamed rubber composition is applied, and the method of molding the elastic layer 3 is also continuous vulcanization by extrusion molding, molding by injection, molding etc. There is no particular limitation. The effective temperature of the foamed rubber composition is preferably 100 ° C. or more and 300 ° C. or less, and more preferably 150 ° C. or more and 250 ° C. or less.

  The elastic layer 3 formed in this manner is cut at its both ends, and its surface is polished and ground to adjust its outer diameter, surface condition and the like. In addition, the elastic layer 3 may have a primer layer formed before the release layer 4 is formed.

<Image forming apparatus>
Next, an example of a fixing device and an image forming apparatus provided with the elastic roller 1 of the present invention will be described with reference to FIG.

  Since the elastic roller 1 of the present invention has the above-mentioned characteristics, it is suitably used as the fixing roller 53 or the pressure roller 56 mounted on the fixing device provided in the image forming apparatus 30.

  As shown in FIG. 3, the image forming apparatus 30 according to the present invention is disposed around a rotatable image carrier 31, such as a photosensitive member, on which an electrostatic latent image is formed, and the image carrier 31, A charging unit 32, for example, a charging roller, an exposure unit 33, a developing unit 40, a transfer unit 34, for example, a transfer roller and a cleaning unit 37, and a fixing device 35 on the downstream side of the recording medium conveyance direction. The developing unit 40 is basically formed in the same manner as the conventional developing unit. Specifically, as shown in FIG. 3, the developer storage portion 41 and the developer 42 are supplied to the image carrier 31. The developer carrier 44, the developer supply means 43 for supplying the developer 42 to the developer carrier 44, and the developer regulating member 45 for charging the developer 42 are provided.

  The fixing device 35 has an endless belt support disposed in the vicinity of the fixing roller 53 and the fixing roller 53 in a case 50 having an opening 52 through which the transferred object 36 passes, as a cross section of which is shown in FIG. The roller 54, the endless belt 55 wound around the fixing roller 53 and the endless belt supporting roller 54, the pressure roller 56 in pressure contact with the fixing roller 53 via the endless belt 55, and the noncontacting endless belt 55 And the heating means 57 for heating the fixing roller 53 from the outside via the endless belt 55, and the fixing roller 53 and the pressure roller 56 rotate so as to abut or press against each other via the endless belt 55. It is a pressure heat fixing device supported freely.

  The endless belt support roller 54 may be any roller that is usually used in an image forming apparatus, and for example, an elastic roller or the like is used. The endless belt 55 may be, for example, an endless belt formed of a resin such as polyamide and polyamideimide, and the thickness and the like can be appropriately adjusted to be suitable for the fixing device 35. The pressure roller 56 is in pressure contact with the fixing roller 53 via the endless belt 55 by urging means (not shown) such as a spring. In the fixing device 35, a pressure roller 56 is mounted. As the heating means 57, a radiation heating method using a halogen heater, a reflection plate or the like, a direct contact heating method in which a heater or the like is brought into direct contact and heating, an induction heating method or the like is adopted. The heating means 57 is a member having a length substantially the same as the length in the axial direction of the fixing roller 53, and may be disposed in any of the fixing devices 35, but as shown in FIG. The fixing roller 53 may be disposed substantially parallel to the fixing roller 53 at a constant distance from the surface. In the induction heating method, a heating coil is used, and the heating coil is a ferromagnetic material such as ferrite and is a typical shape used for a switching power supply, and it is an I-type, an E-type and a U-type. Etc., and the conducting wire is wound. As the transferred material 36 passes between the endless belt 55 and the pressure roller 56 in pressure contact, the developer 42 (electrostatic latent image) transferred to the transferred material 36 is heated simultaneously with the pressurization. It can be fixed.

  The image forming apparatus 30 of the present invention operates as follows. First, in the image forming apparatus 30, the image carrier 31 is uniformly charged by the charging unit 32, and an electrostatic latent image is formed on the surface of the image carrier 31 by the exposure unit 33. Subsequently, the developer 42 is supplied from the developing means 40 to the image carrier 31 to develop the electrostatic latent image, and the developer image is conveyed between the image carrier 31 and the transfer means 34. Transcribed on top. The transferred material 36 is conveyed to the fixing device 35, and the developer image is fixed on the transferred material 36 as a permanent image. In this manner, an image can be formed on the transferred object 36.

  Since the image forming apparatus 30 of the present invention is equipped with the elastic roller 1 of the present invention, the endless belt 55 does not shift in the axial direction of the elastic roller 1 and can be stably operated.

Example 1
The shaft (diameter 20 mm × length 350 mm, SUM 22) subjected to the electroless nickel plating treatment was washed with toluene, and a primer “No. 101A / B” (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied. The primer-treated shaft was fired at a temperature of 180 ° C. for 30 minutes using a gear oven, and then cooled at normal temperature for 30 minutes or more to form a primer layer.

  Next, 100 parts by mass of a mixture of a vinyl group-containing silicone raw rubber and a silica-based filler (a silicone rubber composition “KE-904FU” manufactured by Shin-Etsu Chemical Co., Ltd.) and “Cross-linking agent” manufactured by Shin-Etsu Chemical Co., Ltd. 3 parts by mass of “C-25B” (trade name, addition reaction crosslinking agent) and 2 parts by mass of “C-25A” (trade name, platinum catalyst) manufactured by Shin-Etsu Chemical Co., Ltd. as “catalyst” , 3 parts by mass of "AZO series" (trade name, AIBN) manufactured by Otsuka Chemical Co., Ltd. as "chemical foaming agent" are sufficiently kneaded with two rolls to prepare an addition reaction type foamed silicone rubber composition did.

The shaft on which the primer layer is formed and the addition reaction type silicone rubber composition are integrally separated by an extrusion molding machine, and the addition reaction type silicone rubber composition is heated at 250 ° C. using an infrared heating furnace (IR furnace). It was heated for a minute to cause foam crosslinking. Thereafter, using a gear oven, the addition reaction-type foamable silicone rubber composition after foam crosslinking was subjected to secondary heating at 200 ° C. for 7 hours, and left at room temperature for 1 hour or more. While cutting both ends of this molded body, the surface layer was polished to form an elastic layer having an outer diameter of 10 mm. In this elastic layer, the angle β between the long axis of a single hole contained in the elastic layer and the shaft is measured using “PORE! SCAN”, and a hole with β of 0 ° or more and less than 90 ° and the prevalence _{C 0-90,} beta is a incidence _{C 90-180} of holes equal to or less than 180 ° 90 ° or more, one end of the elastic layer, or 10% from the other end of 0%, and a surface layer 0% The elastic layer in the region of 33% from the above, and the elastic layer in the region of the axial central portion 10% of the elastic layer and the surface layer of 0% to 33% were examined. As a result, C _0-90 of the elastic layer in the region of 0% to 10% of one end of the elastic layer and 0% to 33% of the surface layer is 35%, and C _90-180 is 65%, C _0-90 of the elastic layer in the region of 0% to 10% of the other end of the elastic layer and 0% to 33% of the surface layer is 63%, C _90-180 is 37%, and the elastic layer is The C _0-90 of the elastic layer in the region of the axial central portion 10% and the surface layer 0% to 33% was 48%, and the C _90-180 was 52%.

Example 2
The elastic layer is manufactured under the same conditions as in Example 1, and the cut amount of both ends of the hardened elastic layer and the polishing amount of the surface layer are adjusted, and one end of the elastic layer is 0% to 10%, and the surface layer 0 C _0-90 of the elastic layer in the% to 33% region is 44%, C _90-180 is 56%, the other end of the elastic layer 0% to 10%, and the surface layer 0% to 33 _C0-90 of the elastic layer in the% area is 59%, _C90-180 is 41%, and the elastic property in the area of 10% in the axial center of the elastic layer and in the surface layer of 0% to 33% A fuser roller was produced having an elastic layer in which the C _{0-90 of the} layer is 49% and the C _90-180 is 51%.

Comparative Example 1
The elastic layer is manufactured under the same conditions as in Example 1, and the cut amount of both ends of the hardened elastic layer and the polishing amount of the surface layer are adjusted, and one end of the elastic layer is 0% to 10%, and the surface layer 0 C _0-90 of the elastic layer in the% to 33% region is 38%, C _90-180 is 62%, the other end of the elastic layer 0% to 10%, and the surface layer 0% to 33 C _0-90 of the elastic layer in the% area is 42%, C _90-180 is 58%, and the elastic property in the area of 10% in the axial center of the elastic layer and in the surface layer of 0% to 33% A fuser roller was produced having an elastic layer in which the C _{0-90 of the} layer is 51% and the C _90-180 is 49%.

<Evaluation>
Each test roller manufactured in this manner was disposed as a fixing roller of an electrophotographic printer (manufactured by Oki Data Co., Ltd., trade name: “MICROLINE 1032 PS”, resolution 1200 dpi equivalent). At this time, the positions of the endless belt and the end of each test roller were matched. The endless belt, the developer, and the developer regulating member used the developer and the developer regulating member attached to the electrophotographic printer. The electrophotographic printer was operated to print 10,000 sheets of A4 plain paper. After that, the operation of the electrophotographic printer was stopped, and the positional deviation between the endless belt and each test roller was measured.

  As shown in Table 1, in the elastic roller of the present invention, as compared with the elastic roller of the comparative example, the axial displacement of the endless belt during operation is effectively suppressed and stably operated. Was possible.

Reference Signs List 1 elastic roller 2 shaft 3 elastic layer 4 release layer 30 image forming device 31 image carrier 32 charging unit 33 exposure unit 34 transfer unit 35 fixing unit 36 transfer target member 37 cleaning unit 40 developing unit 41 developer storage portion 42 development Agent 43 Developer Supply Means 44 Developer Carrier 45 Developer Regulating Member 50 Case 52 Opening 53 Fixing Roller 54 Endless Belt Support Roller 55 Endless Belt 56 Pressure Roller 57 Heating Means 70 Testing Machine 71 Heating Roller 72 Internal Heater 73 External Heater 74 Test roller mounting part 75 Pressure adjustment means

Claims (5)

An elastic roller comprising at least a shaft and a porous elastic layer formed on the outer peripheral surface of the shaft,
_Let β be the angle between the longitudinal axis of a single hole contained in the elastic layer and the shaft, and _let C _0-90 be the appearance ratio of holes where β is 0 ° or more and less than 90 °; β is 90 ° or more _Assuming that the appearance rate of the holes which is 180 ° or less is C _90-180 ,
C _0-90 in the elastic layer in the region of 0% to 10% of one end of the elastic layer and 0% to 33% of the surface layer, 0% to 10% of the other end of the elastic layer, and 0% to 33% of the surface layer An elastic roller, wherein the difference between C _90-180 in the elastic layer in the area of is greater than 0% and not more than 15%. Axial center 10% of the elastic layer, and the elastic layer of the 33% region from the surface layer _0% is _{C 0-90,} and 45% or less than _{55%, C 90-180} is 45% or more 55% The elastic roller according to claim 1, wherein   The elastic roller according to claim 1 or 2, wherein the hole diameter of the holes contained in the elastic layer is 30 μm or more and 300 μm or less.   The elastic roller according to any one of claims 1 to 3, wherein the thickness of the elastic layer is 1 mm or more and 60 mm or less.   An image forming apparatus comprising the elastic roller according to any one of claims 1 to 4 as a fixing roller or a pressure roller.