JP4219208B2 - Toner supply roller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner supply roller.
[0002]
[Prior art]
Conventionally, in an image forming apparatus such as a copying apparatus, an image recording apparatus, a printer, and a facsimile, an electrostatic latent image formed on an image carrier made of an electrophotographic photosensitive member or an electrostatic recording dielectric is developed by a developing device. Development is performed with toner (developer) supplied from a roller to visualize the toner image. In such a developing device, in order to supply an appropriate amount of toner of about 10 μm or less accommodated in the hopper to the developing roller, or to scrape it off, a cylindrical elastic body is provided on the outer periphery of the shaft. Built-in roller.
[0003]
As the toner supply roller, an elastic roller provided with polyurethane foam or silicone foam on the outer periphery of the shaft is used (see Patent Document 1 and Patent Document 2). Further, as a method of manufacturing the elastic roller, (1) a method of cutting a roller material from a foam material of slab foaming or mold foaming, passing the shaft through it, and polishing the surface of the roller material to finish it into a roller shape, (2) After forming the roller material integrally with the shaft, polishing the unnecessary portion of the roller material to finish it into a roller shape, (3) Foaming the roller material integrally with the shaft in a roller-shaped mold And (4) a method in which an elastic body is formed into a cylindrical body by peeling processing, and burrs generated by peeling processing are melted (see Patent Document 3).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 3-155575 [Patent Document 2]
JP 2002-328523 A [Patent Document 3]
Japanese Patent Laid-Open No. 10-104937
[Problems to be solved by the invention]
The toner supply roller rotates while being in contact with the outer surface of the developing roller, and has an action of supplying the toner to the developing roller by the rotation and an action of collecting the remaining toner from the developing roller. In addition, it is known that the toner tends to be deteriorated such as fine powder. When the toner is deteriorated, a problem that the toner adheres to an unprinted portion easily occurs.
[0006]
Conventionally, in order to suppress the deterioration of the toner, a countermeasure has been proposed in which the flexible polyurethane foam or the like is formed of a foam layer having a low hardness, and the toner supply roller is appropriately pressed against and brought into contact with the developing roller.
[0007]
However, the toner collected by the toner supply roller is once captured by the opening hole on the surface of the foam layer in the toner supply roller, and the foam layer is deformed and restored when the toner supply roller rotates in contact with the developing roller. As a result, a part of the toner is pushed out from the open hole, and most of the toner trapped in the open hole is not pushed out and is held in the open hole as it is. Accordingly, the rotation of the toner supply roller repeats that the toner is further captured by the open hole on the surface of the foam layer, and the captured toner gradually enters the inside of the foam layer. As a result, the trapped toner is deposited inside the foamed layer, solidified, and solidified to increase the hardness of the foamed layer surface, and the effect of lowering the foamed layer is impaired. Toner deterioration is promoted.
[0008]
Further, in the conventional method for manufacturing a toner supply roller, in the polishing method, if the polishing residue remains on the roller surface, the residue will fall off during use of the toner supply roller and betWeen the developing roller and the toner regulating blade. The toner is scraped off and the white streaks appear on the image. On the other hand, when the outer shape is processed by grinding, it is not easy to completely remove the beard-like processing residue, and if there is a processing residue, white streaks appear in the image. In the peeling method, the blade is applied to the rotating elastic body, so that the soft elastic body can easily escape from the blade edge, and the edge is not formed into a smooth cylinder at the position where the blade edge enters and exits. The manufactured toner supply roller causes uneven friction with the developing roller, increases the stress on the toner, and easily deteriorates the toner over a long period of time.
[0009]
The present invention has been made in view of the above points, and reduces clogging due to toner remaining in the elastic porous body on the roller surface, and suppresses the falling off of abrasive powder and cutting powder on the surface of the elastic porous body. A toner supply roller capable of obtaining an image is provided.
[0010]
[Means for Solving the Problems]
According to the first aspect of the present invention, in the toner supply roller in which a cylindrical elastic porous body having an open cell structure is provided on the outer periphery of the shaft, long fibers are parallel to the axial direction of the shaft in the elastic porous body. The present invention relates to a toner supply roller characterized in that a plurality of them are embedded at positions substantially concentrically with the outer periphery of the shaft.
[0011]
According to a second aspect of the present invention, in the toner supply roller in which a cylindrical elastic porous body having an open cell structure is provided on the outer periphery of the shaft, a long fiber is spirally surrounded in the elastic porous body to surround the outer periphery of the shaft. The present invention relates to a toner supply roller that is embedded.
[0012]
A third aspect of the invention is characterized in that, in the first or second aspect, the polymer emulsion is impregnated from the outer peripheral surface of the elastic porous body to a position where the long fibers are present.
[0013]
According to a fourth aspect of the present invention, in the third aspect, the inner side of the elastic porous body is longer than the position where the long fibers are present, and is more outward than the unimpregnated state of the polymer emulsion or the position where the long fibers are present. It is characterized by being relatively impregnated in comparison with.
[0014]
According to a fifth aspect of the present invention, the impregnated layer of the polymer emulsion is formed more densely than the other part in the third or fourth aspect in a position substantially concentric with the outer periphery of the shaft through the site where the long fibers are present. It is characterized by being.
[0015]
The invention of claim 6 is characterized in that, in any one of claims 3 to 5, the polymer emulsion contains a conductive filler.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below. 1 is a perspective view of a toner supply roller according to a first embodiment of the present invention, FIG. 2 is a partial cross-sectional view parallel to the axial direction of the shaft in the first embodiment, and FIG. 3 is an axis of the shaft in the first embodiment. FIG. 4 is a perspective view of a toner supply roller according to the second embodiment, FIG. 5 is a partial sectional view parallel to the axial direction of the shaft in the second embodiment, and FIG. 6 is a shaft in the second embodiment. FIG. 7 is a perspective view of the toner supply roller according to the third embodiment, FIG. 8 is a partial sectional view parallel to the axial direction of the shaft in the third embodiment, and FIG. 9 is the third embodiment. FIG. 10 is a perspective view of a toner supply roller according to the fourth embodiment, FIG. 11 is a partial cross-sectional view parallel to the axial direction of the shaft in the fourth embodiment, and FIG. The shi in the fourth embodiment It is a cross-sectional view perpendicular to the shift axis.
[0017]
A toner supply roller 10A according to the first embodiment shown in FIGS. 1 to 3 includes a shaft 11A and an elastic porous body 21A provided in a cylindrical shape on the outer periphery of the shaft 11A, and includes a copying apparatus, an image recording apparatus, Used in image forming apparatuses such as printers and facsimiles.
[0018]
The shaft 11A serves as a rotating shaft of the toner supply roller 10A, is made of a material having a required rigidity such as metal, and is sized according to the toner supply roller 10A.
[0019]
The elastic porous body 21A has an open cell structure such as urethane foam or silicone foam, and has an open hole due to the opening of bubbles on the surface. In particular, urethane foam having an open-cell structure having a density of 10 to 500 kg / m ³ , a cell diameter of 10 to 500 μm, and a hardness of 10 to 90 ° (Asuka F hardness meter) is suitable as the elastic porous body 21A. The outer diameter of the elastic porous body 21A is larger than the outer diameter of the shaft 11A, and is appropriately set. An example of the outer diameter of the elastic porous body 21A is about 7 to 15 mm. Further, when the toner supply roller 10A is required to have conductivity, the elastic porous body 21A may contain a conductive filler.
[0020]
The cylindrical elastic porous body 21A is processed by (a) cutting out a block-shaped elastic porous body of a required size from a slab foamed or mold-foamed elastic porous body and bonding it through a shaft to the surface of the block-shaped elastic porous body. (B) A method in which an elastic porous body is formed integrally with the shaft, and then an unnecessary portion of the elastic porous body is polished to finish into a roller-shaped cylinder. ) Either a method of foaming an elastic porous body integrally with a shaft in a roller-shaped mold, or (d) a method of forming a cylindrical body by peeling the elastic porous body and melting burrs generated by the peeling processing, etc. . In the case of the method (A), the shaft 11A and the block-like elastic porous body are bonded by an appropriate bonding method such as an adhesive. Examples of the adhesive include a two-component polyurethane adhesive, an epoxy adhesive, a polyester adhesive, an acrylic adhesive, an acrylic emulsion adhesive, and a urethane emulsion adhesive. Further, when the toner supply roller 10A is required to be conductive, the adhesive may be made of a conductive material.
[0021]
A plurality of long fibers 22A are embedded in the elastic porous body 21A at a predetermined interval at a position substantially concentric with the outer periphery of the shaft 11A in parallel with the axial direction of the shaft 11A. As the long fibers 22A, known natural or synthetic resin long fibers can be used. The thickness is preferably 10 to 200 μmφ. Examples include cotton, wool, silk, rayon, polypropylene, polyester, nylon, acrylic fiber, and the like. The interval d between the long fibers 22A is set appropriately, but in order to enhance the function of preventing the intrusion of toner from the surface of the elastic porous body 21A, it is preferable to embed the fibers at an interval of 0.1 to 2.0 mm. . Moreover, the position of the long fibers 22A in the radial direction of the elastic porous body 21A is preferably about 0.5 to 2.0 mm from the outer peripheral surface of the elastic porous body 21A. The long fibers 22A are embedded in the elastic porous body 21A by passing the long fibers 22A through a needle hole formed at the tip of a long needle and passing the needle in the axial direction of the cylindrical elastic porous body 21A. It can be performed by piercing from the one end surface 211A to the other end surface 212A, or by repeatedly folding back at the other end surface 212A to pierce again to the one end surface 211A and pierce again to the other end surface 212A.
[0022]
The toner supply roller 10B according to the second embodiment shown in FIGS. 4 to 6 is characterized in that a polymer emulsion is impregnated in the elastic porous body 21B from the outer peripheral surface of the cylindrical elastic porous body 21B. The configuration of is the same as that of the first embodiment. 4 to 6, reference numeral 11B denotes a shaft, 22B denotes long fibers, and 211B and 212B denote one end surface and the other end surface in the axial direction of the elastic porous body 21B.
[0023]
The polymer emulsion has an action of more effectively suppressing the intrusion of toner from the surface of the elastic porous body 21B. Further, when the elastic porous body 21B is subjected to surface processing by polishing or cutting, the abrasive powder or cutting powder that has entered and adhered to the open holes on the surface of the elastic porous body 21B during the polishing or cutting is the toner supply roller. 10B is effective in preventing the elastic porous body 21B from falling off and causing image defects such as white streaks due to the abrasive powder and cutting powder to be less likely to occur. Reference numeral 23B denotes a portion impregnated with the polymer emulsion. The polymer emulsion preferably has a glass transition temperature of about 10 ° C. or lower and becomes an elastomer in the usage environment of the toner supply roller 10B. Examples include latex or emulsion of natural rubber (NR), styrene butadiene rubber (SBR), chloroprene rubber (CR), nitrile rubber (NBR), fluoro rubber, polyurethane, polyester and the like. The viscosity of the polymer emulsion is preferably 1,000 mPa · s to 100,000 mPa · s at 23 ° C. The polymer emulsion may contain a conductive filler such as carbon black. The polymer emulsion is impregnated efficiently in a short time by applying the polymer emulsion uniformly on the outer peripheral surface of the elastic porous body 21B with a roll coater and then spraying high-pressure air on the coated surface. Can be made.
[0024]
Further, in the illustrated second embodiment, a plurality of long fibers 22B embedded in the elastic porous body 21B in parallel with the axial direction of the shaft 11B and at a substantially circumferential position include the polymer emulsion. In the elastic porous body 21B, the inner side of the elastic porous body 21B is not impregnated with the polymer emulsion (the state shown in FIGS. 4 to 6), or the long fiber. The amount of impregnation is relatively smaller than the position where 22B exists (not shown). The action of the impregnation preventing layer by the long fibers 22B is because the polymer emulsion is difficult to pass between the long fibers 22B due to its own viscosity.
[0025]
Further, the elastic porous body 21B passes through a portion where the plurality of long fibers 22B exist, and is positioned more concentrically with the outer periphery of the shaft by the impregnation preventing layer by the long fibers 22B. The polymer emulsion that is prevented from freely entering the film forms the impregnated layer 24B that is denser than the other part. The dense impregnation layer 24B of the polymer emulsion can more effectively prevent the toner from entering the content from the surface of the elastic porous body 21B than the dense impregnation layer 23B. It is possible to prevent clogging in the porous body 22B.
[0026]
In the toner supply roller 10C according to the third embodiment shown in FIGS. 7 to 9, the long fiber 22C spirals from one end side to the other end side of the cylindrical elastic porous body 21C and surrounds the outer periphery of the shaft 11C. As described above, it is embedded in the elastic porous body 21C, and other configurations are the same as those in the first embodiment.
[0027]
The burying position of the long fibers 21C in the radial direction of the elastic porous body 21C is the same as in the first embodiment. The interval (pitch) p between the long fibers 21C embedded in the spiral is more preferably 0.1 to 2.0 mm from the viewpoint of preventing the toner from entering. A method of embedding the long fibers 21C in the elastic porous body 22C in a spiral shape is not particularly limited. As an example, a spiral needle having a spiral shape (screw shape) similar to that of a corkscrew and having a needle hole formed at the tip is used, and the long fibers are passed through the tip of the spiral needle to form the elastic porous body 21C. The spiral needle is pierced while rotating from one end surface 211C to the other end surface 212C, and when the long fiber 22C protrudes outward from the other end surface 212C, the protruding portion of the long fiber 22C is held, and the spiral needle is reversed. And a method of extracting the spiral needle from the one end face 211C. The action of the long fibers 22C spirally embedded in the elastic porous body 21C is the same as that of the long fibers 22A of the first embodiment, and suppresses further penetration of toner.
[0028]
The toner supply roller 10D according to the fourth embodiment shown in FIGS. 10 to 12 is impregnated with the same polymer emulsion as in the second embodiment from the outer peripheral surface of the cylindrical elastic porous body 21D in the third embodiment. Other features are the same as in the third embodiment.
[0029]
In the fourth embodiment, the long fibers 22D spirally embedded in the elastic porous body 21D have the same function as that of the long fibers 22B in the second embodiment, that is, the intrusion of the toner. An impregnation layer 24D of a polymer emulsion that prevents impregnation to the inside and is denser than the other part is formed so as to be substantially concentric with the shaft 11D through the portion of the long fibers 22D. Reference numeral 23D denotes a portion where the polymer emulsion is impregnated from the surface of the elastic porous body 21D to the long fibers 22D.
[0030]
【Example】
Example 1
A shaft hole having a diameter of 4 mm along the longitudinal direction in a block (28 mm × 28 mm × 330 mm) of urethane foam having an open cell structure (product number: SM50, cell diameter: 200 to 500 μm, density 50 kg / m ³ , manufactured by INOAC Corporation) And a shaft made of steel material having a diameter of 5 mm coated with a hot melt adhesive made of ethylene vinyl acetate copolymer (EVA) to a thickness of about 50 μm (those subjected to electrolytic nickel plating) is inserted into the shaft hole, A block of urethane foam was bonded to the shaft by heating and cooling. The both ends of the shaft were held and the outer periphery of the urethane foam was ground to form an elastic porous body having a cylindrical shape having a diameter of 12 mm and a length of 320 mm on the outer periphery of the shaft.
[0031]
Next, at a position of 1.0 mm from the outer peripheral surface of the elastic porous body, long fibers (ace crown filament sewing thread, # 100, 33 dtex, manufactured by Kanagawa Co., Ltd.) from one end surface to the other end surface of the elastic porous body, The toner supply roller of Example 1 (toner supply roller 10A in FIGS. 1 to 3) was obtained by piercing and embedding 60 threads at equal intervals in the circumferential direction so as to be substantially concentric with the outer peripheral surface of the shaft.
[0032]
(Example 2)
Acrylic resin emulsion (product number: Nipol LX851, manufactured by Nippon Zeon Co., Ltd., 45% solid content) is 70% by weight, and carbon black dispersion (product number: Emacol Black, manufactured by Sanyo Color Co., Ltd., solid content 36%) is 27% by weight. Then, a thickener (sodium polyacrylate, manufactured by Toa Gosei Co., Ltd.) 3% by weight was blended and stirred sufficiently to prepare a water-based polymer emulsion (water-based paint) having conductivity. The viscosity of this polymer emulsion (water-based paint) was controlled at 23 ° C. according to JIS Z8803-1991, a liquid viscosity measurement method, using a single cylindrical rotational viscometer (TV-10 type, manufactured by Toki Sangyo). As a result of measuring the viscosity at 0.6 rpm and then 60 rpm in the warm bath, it was 21000 mPa · s at 0.6 rpm and 2300 mPa · s at 60 rpm.
[0033]
Further, 20 g of the polymer emulsion (water-based paint) was uniformly applied to the outer peripheral surface of the elastic porous material after embedding the long fibers in Example 1 using a roll coater, and then high-pressure air of 0.5 MPa was elastically porous. The applied polymer emulsion (water-based paint) was sprayed onto the surface of the body with an air gun so that the cell structure of urethane foam opened on the surface of the elastic porous body was made visible. Subsequently, a solution obtained by dissolving 24.1 g (about 0.1 mol) of aluminum chloride (3) hexahydrate as a gelling agent in 1 L of pure water was spray-coated (coating amount: about 3 g), and gelled. Drying and curing were performed in a hot air circulating oven at 100 ° C. for 30 minutes to obtain a toner supply roller of Example 2 (toner supply roller 10B in FIGS. 4 to 6).
[0034]
(Example 3)
A toner supply roller of Example 3 (toner supply roller 10C in FIGS. 6 to 9) was obtained in the same manner as in Example 1 except that long fibers were embedded in the elastic porous body in a spiral manner. The pitch of the long fibers embedded in a spiral shape is 2.0 mm.
[0035]
(Example 4)
In Example 3, the long fibers were spirally embedded in the elastic porous body, and then the same polymer emulsion (water-based paint) 20 g as in Example 2 was uniformly applied to the outer peripheral surface of the elastic porous body using a roll coater. The toner supply roller of Example 4 (toner supply roller 10D in FIGS. 10 to 12) was obtained in the same manner as in Example 2 except that coating was performed.
[0036]
(Comparative example)
A shaft hole having a diameter of 4 mm along the longitudinal direction in a block (28 mm × 28 mm × 330 mm) of urethane foam having an open cell structure (product number: SM50, cell diameter: 200 to 500 μm, density 50 kg / m ³ , manufactured by INOAC Corporation) And a shaft made of steel material having a diameter of 5 mm coated with a hot melt adhesive made of ethylene vinyl acetate copolymer (EVA) to a thickness of about 50 μm (those subjected to electrolytic nickel plating) is inserted into the shaft hole, A block of urethane foam was bonded to the shaft by heating and cooling. The both ends of the shaft were held and the outer periphery of the urethane foam was ground to form an elastic porous body having a cylindrical shape having a diameter of 12 mm and a length of 320 mm on the outer periphery of the shaft. In the same manner as in FIG. 1, 20 g of the polymer emulsion (water-based paint) was applied to the outer peripheral surface of the elastic porous body, dried and cured to obtain a toner supply roller of a comparative example.
[0037]
The toner supply rollers of Examples 1 to 4 and the comparative example are attached to the same type of laser printer, a character string having a toner density of about 5% is printed, and two black solid (single black) images are continuously printed every 1000 sheets. Then, printing was continued up to 10,000 sheets, and an image evaluation test was conducted with the occurrence of defects as a case where even the density unevenness or white streaks were observed to the naked eye even in the output printed matter of the black solid image. In addition, the roller used for the said image evaluation test has four each in Examples 1-4 and a comparative example, It attached to the laser printer one by one and measured.
[0038]
As a result of the image evaluation of the image measurement, all of the rollers of Examples 1 to 4 did not generate image unevenness or white streak up to 10,000 sheets. On the other hand, in the roller of the comparative example, the density unevenness is generated in two of the total number of black solid image outputs of the four rollers when the cumulative number of printed sheets of each roller is 5000 (defect occurrence rate of 25%). , 4 out of 8 sheets of black solid image output at 6000 sheets (defect occurrence rate 50%), 8 out of 8 sheets of black solid image output at 7000 sheets (defect occurrence) 100%), and thereafter, 8000 sheets, 9000 sheets, and 10000 sheets all generated 8 out of 8 sheets of black solid image output (defect occurrence rate 100%). Further, in the comparative example, white streaks occur at the time when the total number of printed sheets of each roller is 8000, four out of the total number of black solid image outputs (the defect occurrence rate is 50%), and at the time of 9000 sheets, the black solid is black. Eight out of the total number of 8 image outputs (defect occurrence rate 100%). At the time of 10,000, 8 out of the total number of black solid image outputs 8 (defect occurrence rate 100%). This is because the toner supply rollers of Examples 1 to 4 are less likely to be clogged with toner by the long fibers embedded in the elastic porous body, and in Examples 2 and 4, the polymer emulsion impregnated from the surface of the elastic porous body is used. It is assumed that the grinding powder is less likely to fall off.
[0039]
【The invention's effect】
As described above, according to the toner supply roller of the present invention, the long fibers embedded in the elastic porous body function to suppress further intrusion with respect to the toner that has entered the elastic porous body. There is an effect that clogging with toner is less likely to occur, and image defects due to the clogging are less likely to occur. Further, in the case where a polymer emulsion is impregnated from the surface of the elastic porous body, the impregnated polymer emulsion prevents the polishing powder and grinding powder of the elastic porous body from falling off the elastic porous body. Therefore, there is an effect that it is difficult to cause image defects.
[Brief description of the drawings]
FIG. 1 is a perspective view of a toner supply roller according to a first embodiment of the present invention.
FIG. 2 is a partial cross-sectional view parallel to the axial direction of a shaft in the first embodiment.
FIG. 3 is a transverse cross-sectional view orthogonal to the axial direction of the shaft in the first embodiment.
FIG. 4 is a perspective view of a toner supply roller according to a second embodiment.
FIG. 5 is a partial cross-sectional view parallel to the axial direction of a shaft in a second embodiment.
FIG. 6 is a cross-sectional view orthogonal to the axial direction of the shaft in the second embodiment.
FIG. 7 is a perspective view of a toner supply roller according to a third embodiment.
FIG. 8 is a partial cross-sectional view parallel to the axial direction of a shaft in a third embodiment.
FIG. 9 is a transverse cross-sectional view orthogonal to the axial direction of the shaft in the third embodiment.
FIG. 10 is a perspective view of a toner supply roller according to a fourth embodiment.
FIG. 11 is a partial cross-sectional view parallel to the axial direction of a shaft in the fourth embodiment.
FIG. 12 is a cross-sectional view orthogonal to the axial direction of the shaft in the fourth embodiment.
[Explanation of symbols]
10A, 10B, 10C, 10D: toner supply rollers 11A, 11B, 11C, 11D of the first, second, third, and fourth embodiments: shafts 21A, 21B, 21C, 21D: elastic porous bodies 22A, 22B, 22C , 22D: long fibers 24B, 24D: dense impregnated layer

Claims (6)

In the toner supply roller (10A) in which a cylindrical elastic porous body (21A) having an open cell structure is provided on the outer periphery of the shaft (11A),
A plurality of long fibers (22A) are embedded in the elastic porous body (21A) parallel to the axial direction of the shaft (11A) and at a position substantially concentrically with the outer periphery of the shaft (11A). Toner supply roller. In the toner supply roller (10B) in which a cylindrical elastic porous body (21B) having an open cell structure is provided on the outer periphery of the shaft (11B),
A toner supply roller in which long fibers (22B) are embedded in a spiral shape surrounding the outer periphery of the shaft (11B) in the elastic porous body (21B). The toner supply roller according to claim 1, wherein a polymer emulsion is impregnated from an outer peripheral surface of the elastic porous body to a position where the long fibers are present.   In the elastic porous body, the inner side of the position where the long fibers are present is not impregnated with the polymer emulsion or the impregnated state is relatively smaller than the outer side than the position where the long fibers are present. The toner supply roller according to claim 3.   5. The impregnated layer of the polymer emulsion is formed more densely than the other part at a position substantially concentric with the outer periphery of the shaft through the site where the long fibers are present. The toner supply roller as described.   The toner supply roller according to claim 3, wherein the polymer emulsion contains a conductive filler.

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