JP4170869B2 - Manufacturing method of toner supply roller - Google Patents

Description

The present invention relates to a method for manufacturing a toner supply roller.

  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 with toner (developer) supplied to a roller to visualize the toner image is performed. In such a developing device, a toner supply roller is incorporated in order to supply an appropriate amount of toner of about 10 μm or less contained in the hopper to the developing roller, or to scrape excess toner from the developing roller.

  As the toner supply roller, an elastic roller in which a foam layer such as polyurethane foam or silicone foam is provided on the outer periphery of the shaft has been proposed (see Patent Document 1 and Patent Document 2). In addition, as a method for producing the elastic roller, (1) a foam layer material is cut out from a foam material of slab or mold foam, passed through a shaft, and then the surface of the foam layer material is ground or polished to form a cylindrical shape. A method of finishing into a roller shape, (2) a method of forming a foamed layer material integrally with the shaft, and then grinding and polishing unnecessary portions of the foamed layer material to finish into a cylindrical roller shape, and (3) a roller-shaped die (4) a method of foaming a foam layer integrally with a shaft, (4) a method in which an elastic body is made into a cylindrical body by peeling processing, and a burr on the surface of the cylindrical body generated by peeling processing is melted (see Patent Document 3). ).

  The toner supply roller rotates while being in contact with the outer surface of the developing roller, and has an operation of supplying the toner to the developing roller by the rotation and an operation of scraping and collecting the remaining toner from the developing roller. The toner is subject to mechanical stress by rubbing between the toner supply roller and the developing roller, and the collected toner is likely to be deteriorated such as fine powder. Further, when the toner is deteriorated, a problem that the toner adheres to a non-printed portion is likely to occur.

  Conventionally, in order to suppress the deterioration of the toner, a method has been proposed in which the foam layer of the toner supply roller is composed of a low-hardness foam layer such as a soft polyurethane foam so that the pressure of the toner supply roller against the developing roller is moderate. ing.

  However, if the foam layer of the toner supply roller is made to have a low hardness, the scraping ability when collecting the remaining toner from the developing roller is lowered. Further, the toner collection by scraping is performed by the toner supply roller rotating in contact with the developing roller once capturing the toner in the open hole of the cell (pore) on the surface of the foam layer, and further in the state. The toner is rotated while being in contact with the developing roller, and the toner is pushed out of the opening hole on the surface of the foam layer by deformation and restoration of the foam layer by the contact rotation. However, most of the toner trapped on the surface of the foam layer is likely to be trapped in the open hole without being pushed out of the open hole. Therefore, when the toner is further captured in the open hole on the surface of the foamed layer by the rotation of the toner supply roller, the toner captured earlier gradually enters the inside of the foamed layer. As a result, the toner accumulates inside the foam layer of the toner supply roller and solidifies and solidifies, thereby increasing the hardness of the foam layer and reducing the effect of lowering the foam layer. As a result, the deterioration of the toner is promoted. Furthermore, since the open holes on the surface of the foam layer are filled with toner due to the accumulation of the toner, the toner conveying force is remarkably reduced, and a predetermined amount of toner may not be supplied to the developing roller.

Further, in the method of manufacturing the toner supply roller by grinding or polishing, if the grinding residue or polishing residue remains on the foam layer surface (roller surface), the residue may cause white stripes in the image, Residues fall off during use of the toner supply roller and are sandwiched between the developing roller and the toner regulating blade to cause white streaks in the image. Moreover, since grinding powder or polishing powder is generated, the grinding powder or polishing powder adheres to the surface of the foamed layer, and the image may be damaged by the adhered grinding powder or polishing powder. 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. The manufactured toner supply roller that is not formed on the surface is likely to cause non-uniform rubbing with the developing roller, increasing the stress on the toner and causing the toner to deteriorate due to the stress. In addition, the grinding, polishing, or peeling process has a problem of troublesome work.
Japanese Patent Laid-Open No. 3-155575 JP 2002-328523 A JP-A-10-104937

The present invention has been made in view of the above points, and can suppress the stress applied to the toner, can stably supply the toner, does not generate abrasive powder and cutting powder, is easy to manufacture, and has a good image. A method for manufacturing a toner supply roller is obtained.

The present invention relating to a method for producing a toner supply roller is provided with a cylindrical elastic porous body on the outer periphery of a shaft, and a protrusion is twisted with respect to the axis of the elastic porous body on the outer peripheral surface of the elastic porous body. The elastic porous body block made of urethane foam slab is twisted by rotating one end side thereof with respect to the other end side, and between both ends of the elastic porous body block. A cylindrical outer perforation blade in which a plurality of protrusions are formed by bending the outer peripheral surface outward at a predetermined interval between both ends of the elastic porous body block compressed in the twisted state, and a twist compression step for compressing Punching with an inner peripheral punching blade having the same center as the outer peripheral punching blade and having a smaller diameter than the outer peripheral punching blade, and twisting to the outer peripheral surface by releasing the twist and compression. A punching and twist compression release process for obtaining a cylindrical elastic porous body having a protrusion and a shaft insertion hole in the center, and inserting the shaft into the shaft insertion hole of the cylindrical elastic porous body And a shaft insertion step of integrating the shaft with the elastic porous body.

According to the toner supply roller obtained by the manufacturing method of the present invention, the cylindrical elastic porous body provided on the outer periphery of the shaft has a protrusion formed from one end to the other end of the outer peripheral surface. The toner attached to the outer peripheral surface of the elastic porous body is unlikely to drop off from the outer peripheral surface of the elastic porous body, and the toner supply performance is improved. Therefore, it is possible to compensate for a decrease in toner supply performance caused by toner entering from the open holes on the surface of the elastic porous body and clogging the elastic porous body. Further, since the toner supply roller of the present invention comes into contact with the surface of the developing roller at the protruding portion, scraping of excess toner on the surface of the developing roller can be stably performed by the protruding item. Furthermore, even if the toner enters the open holes on the surface of the elastic porous body and clogs the toner, the hardness of the entire surface of the elastic porous body may increase, according to the toner supply roller of the present invention, Since the protrusion on the surface of the elastic porous body contacts the developing roller, the entire surface of the elastic porous body having increased hardness is in contact with the developing roller as compared with the case where the entire surface of the elastic porous body rotates while contacting the developing roller. As a result, the stress applied to the toner rubbed with the toner is reduced, so that deterioration of the toner can be suppressed and a good image can be obtained. Furthermore, by making the elastic porous body a punched product of urethane foam slab, grinding powder and polishing powder can be prevented, and the adverse effect of the image due to the grinding powder and polishing powder can be prevented.

  Further, if the protrusion of the elastic porous body is provided in a state twisted with respect to the axis of the elastic porous body, the toner is applied to the protrusion at the time of scraping excess toner on the surface of the developing roller by rotation of the toner supply roller. Accordingly, the toner is easily guided to the outside of the elastic porous body. As a result, the toner is less likely to be clogged in the open holes on the surface of the elastic porous body, and the scraping action and the image can be further improved.

  According to the manufacturing method of the present invention, the toner supply roller having stable toner supply performance, good scraping action, low stress on the toner, and good image can be obtained by grinding or polishing. And can be manufactured easily.

FIG. 1 is a front view according to an embodiment of a toner supply roller obtained by the production method of the present invention, FIG. 2 is a perspective view of a cylindrical elastic porous body in the embodiment, and FIG. 3 is a view of the production method of the present invention. FIG. 4 is a perspective view showing a torsionally compressed state of the elastic porous body block in the manufacturing embodiment, and FIG. 5 is a perspective view of an example of a punching blade.

  A toner supply roller 10 shown in FIG. 1 includes a shaft 11 and a cylindrical elastic porous body 21 provided on the outer periphery of the shaft 11, and includes an image forming apparatus such as a copying apparatus, an image recording apparatus, a printer, and a facsimile machine. Used for.

  The shaft 11 serves as a rotating shaft of the toner supply roller 10 and is made of a material having a required rigidity such as metal and is sized according to the toner supply roller 10.

The cylindrical elastic porous body 21 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, a punched product of urethane foam slab, preferably a punched product of urethane foam slab 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 used as the elastic porous body 21. Is preferred. The urethane foam slab is suitable as the elastic porous body 21 of the toner supply roller 10 because it has an appropriate hardness, is inexpensive, and can be easily punched out. In addition, since the cylindrical elastic porous body 21 formed by punching does not require troublesome processing such as grinding and polishing thereafter, and no grinding powder or polishing powder is generated, the grinding powder or polishing powder is not elastic rubber 21. The ink adheres to the surface of the elastic porous body 21 or once enters the open hole on the surface of the elastic porous body 21 and then is discharged to the surface of the elastic porous body 21 during use of the toner supply roller 10 to adversely affect the printed image. Can be prevented.

  As shown in FIG. 2, the elastic porous body 21 has a shaft insertion hole 22 at the center, and a plurality of protrusions 24 are formed on the outer peripheral surface 23 from one end to the other end of the outer peripheral surface. The shaft 11 having an outer peripheral surface coated with an adhesive such as a hot melt adhesive is inserted into the shaft insertion hole 22 so that the elastic porous body 21 and the shaft 11 are integrated.

  The protrusion 24 has an appropriate cross-sectional shape such as a triangle or a semicircle, and in this example, has a substantially triangular cross section. Further, the height, width, and interval of the ridges 24 are appropriately determined. The preferred height is 0.5 to 1.0 mm, the width is 1.0 to 2.0 mm, and the angular interval of the protrusions 24 in the circumferential direction of the elastic porous body 21 is 5 to 30 degrees. When the height, width, and interval are within the above ranges, the toner is less likely to stay between the protrusions 24, and the clogging of the toner into the open holes on the surface of the elastic porous body 21 can be reduced. Further, the protrusion 24 is preferably formed in a twisted state (in other words, a spiral shape) with respect to the axis a of the elastic porous body 21 as in the present embodiment. The protrusion 24 preferably has a twisted state in which the angle e between both ends with respect to the axis a of the elastic porous body is greater than 0 degree and less than 40 degrees, and the particularly preferred twisted state is that the angle e is 10 degrees to 30 degrees. is there. Within this range, the toner is easily guided along the protrusions 24 when the toner supply roller 10 is rotated, and toner accumulation between the protrusions 24 can be suppressed.

  The number of the cylindrical elastic porous bodies 21 with respect to the shaft 11 is not particularly limited, but a plurality is preferable. If a plurality of cylindrical elastic porous bodies 21 to be mounted on the shaft 11 are provided, the length d (width along the direction of the shaft 11) of the elastic porous bodies 21 per piece can be reduced, and the elasticity by punching can be reduced. Not only the formation of the porous body 21 is facilitated, but also the frictional resistance when the elastic porous body 21 is mounted on the shaft 11 can be suppressed, and the mounting work on the shaft 11 is facilitated.

  Next, an example in which the toner supply roller 10 is manufactured by the manufacturing method of the present invention will be described. The toner supply roller manufacturing method includes a twist compression step, a punching and twist compression release step, and a shaft insertion step.

In the twist compression step, as shown in FIGS. 3 and 4, in the elastic porous body block 20, one end side m thereof is twisted with respect to the central axis b of the elastic porous body block 20 with respect to the other end side n. The elastic porous body block 20 is compressed between both ends. The elastic porous body block 20 is made of a cut out product of urethane foam slab, and the dimensions thereof are appropriately determined according to the dimensions of the cylindrical elastic porous body 21 in the toner supply roller 10, and the cylindrical elastic porous body 21. Is sized so that at least one can be punched. The elastic porous body block 20 preferably has 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). Further, the shape of the elastic porous body block 20 is an appropriate shape such as a prism, a cylinder, or a plate-like body, but a block having both end faces of a triangle, a quadrangle, and other polygons can be twisted thereafter. It is preferable because it is easy. The illustrated elastic porous body block 20 is made of a cube.

  The elastic porous body block 20 is twisted and compressed by an appropriate method, and the following method is given as an example. That is, the elastic porous body block 20 whose both end faces are polygons (square in the example shown in the figure), and one end face of the frame body 31 fitted to the outer peripheral surface of the end of the elastic porous body block 20 are made of a resin sheet 32. Using jigs 30 and 30 closed with plates, both ends of the elastic porous body block 20 are covered with the jigs 30 and 30 as shown in FIG. 3 and FIG. One end of the elastic porous body block 20 is rotated by a predetermined angle about the central axis b of the elastic porous body block 20, and one end side of the elastic porous body block 20 is twisted by a predetermined angle with respect to the other end side. The rotation angle is greater than 0 degree and less than 45 degree, preferably 15 to 30 degree. In that state, the elastic jig block 20 is compressed by bringing the two jigs 30 and 30 close by a press device or the like. The frame body 31 of the jig 30 is made of a highly rigid material such as metal or resin. The resin sheet 32 is not particularly limited as long as it can be punched, and examples thereof include resin sheets such as PET, ABS, and vinyl chloride.

  The compression of the elastic porous body block 20 is performed in order to increase the hardness of the elastic porous body block 20 and make the elastic porous body block 20 difficult to be deformed and punched out correctly at the time of subsequent punching. The amount of compression is set appropriately, but is generally ½ to ¼ of the thickness of the elastic porous body block 20 before compression.

  In the punching and twist compression release process, the cylindrical elastic porous body 21 shown in FIG. 2 is formed by punching between both ends of the elastic porous body block 20a in the twist compression state with a punching blade and releasing the twist and compression. That is, the cylindrical elastic porous body 21 having the twisted protrusion 24 on the outer peripheral surface is obtained.

  FIG. 5 shows an example of the punching blade 40. The illustrated punching blade 40 is also referred to as a Thomson blade, and a cylindrical outer punching blade 43 and a cylindrical inner punching blade 47 are erected on the substrate 41 with the same center. The outer peripheral punching blade 43 is for punching the outer peripheral surface of the elastic porous body 21 and is made of a metal cylindrical body having a blade formed at the tip, and the outer peripheral surface of the cylindrical body is removed at a predetermined interval. A plurality of protrusions 44 are formed by bending in the direction. The illustrated protrusion 44 has a triangular protrusion shape, and is a straight line parallel to the central axis direction f of the outer peripheral punching blade 43 (perpendicular to the substrate 41), and the outer peripheral surface of the outer peripheral punching blade 43. Is formed. The inner peripheral punching blade 47 is for forming the shaft insertion hole 22 of the elastic porous body 21 and is formed of a cylindrical body having a blade formed at the tip and having a diameter smaller than the diameter of the outer peripheral punching blade 43. The outer diameter of the shaft 11 shown in FIG. 1 is slightly smaller.

  In this embodiment, the punching blade 40 is pierced from the outer surface of the resin sheet 32 of one jig 30 of the elastic porous body block 20a in the torsionally compressed state, and the elastic porous body block 20a is punched together with the resin sheet 32. Thereafter, by removing the punched product from the punching blade 40, the twisting and compression are released. The punching and twist compression releasing steps are repeated as many times as required depending on the number of the elastic porous bodies 21. Once the outer peripheral punching blade 43 and the inner peripheral punching blade 47 are required to be assembled on the substrate 41, The plurality of elastic porous bodies 21 may be punched out by punching.

  In the shaft insertion step, an adhesive such as a hot melt adhesive is applied to the outer peripheral surface of the shaft 11, and the shaft 11 after the adhesive application is made of the required number of shafts of the elastic porous body 21 made of the punched product. The toner 11 is inserted into the insertion hole 22 and melted and cured of the adhesive to integrate the shaft 11 and the required number of the elastic porous bodies 21 to obtain the toner supply roller 10 of FIG.

  The elastic porous body block 20 of 30 × 30 × 30 mm was cut out from urethane foam (product number: EPM70C, manufactured by Inoac Corporation) that was slab foamed. Next, box-shaped jigs 30 and 30 each having an inner dimension of 5.0 mm × 30 mm × 30 mm and a top plate made of a resin sheet 32 made of PET are connected to both ends of the elastic porous body block 20. , One jig 30 is rotated 30 degrees with respect to the other jig 30, the jigs 30, 30 are brought close to each other, and the elastic porous body block 20 is twisted and compressed to a thickness of 10 mm. And the said jig | tool 30,30 was fixed in the aspect.

  Next, the outer peripheral punching blade 43 having an outer diameter of 14 mm in which a plurality of triangular protrusions 44 having a height of 1 mm and a width of 1 mm are formed on the outer peripheral surface at a pitch of 22.5 degrees and the inner peripheral punching blade 47 having an outer diameter of 4 mm are concentric. The punching blade 40 erected on the substrate 41 is used to punch out the elastic porous body block 20a of the twist compression invitation together with the resin sheet 32, and the punched product is removed from the punching blade 40 to twist the outer peripheral surface A cylindrical elastic porous body 21 having strips 24 is obtained.

  The above operation was repeated to form eight cylindrical elastic porous bodies 21, and then the conductive metal shaft 11 having an outer diameter of 4 mm and a length of 270 mm coated with a hot melt adhesive on the outer peripheral surface was replaced with the eight pieces. An elastic porous body in which a protrusion 24 twisted on the outer peripheral surface is formed by inserting into the shaft insertion hole 22 of the elastic porous body 21 and then heating the hot melt adhesive in a hot air drying furnace at 70 ° C. for 30 minutes. The toner supply roller 10 of FIG.

(Comparative example)
The outer peripheral punching blade 43 of the Thomson blade is made into a normal cylindrical shape without the triangular protrusion, and except that the jig 30 is not rotated, the rest is the same as in the above embodiment except that the protrusion is formed on the outer peripheral surface. A comparative toner supply roller having a non-elastic porous body fixed to the shaft was formed.

  The toner supply rollers of the above-mentioned examples and comparative examples are each attached to a laser printer, and images are printed with a durable pattern up to 10,000 sheets, and 100% solid images and 50% half in magenta color every 2,000 sheets. A tone image was test printed, and the image density at a 30 mm site after each printing start and at a 30 mm site before the printing end was measured with a Macbeth densitometer. Table 1 shows the results of density differences between the 30 mm site after the start of printing and the 30 mm site before the end of each image (100% solid image and 50% halftone image). Note that the density difference between the 100% solid image and the 50% halftone image at the 30 mm site after the start of printing was hardly up to 10,000 sheets in both the example and the comparative example.

  As can be seen from Table 1, the toner supply roller of the example has a 30 mm portion after the start of printing for both 100% solid images and 50% halftone images in the range of up to 10,000 durable prints. The density difference from the 30 mm portion before the end was smaller than that of the toner supply roller of the comparative example, and the printed image was good.

FIG. 4 is a front view according to an embodiment of a toner supply roller obtained by the manufacturing method of the present invention. It is a perspective view of the cylindrical elastic porous body in the Example. It is a perspective view of the elastic porous body block and jig | tool in one Example of the manufacturing method of this invention. It is a perspective view which shows the twist compression state of the elastic porous body block in the manufacture example. It is a perspective view of an example of a punching blade.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Toner supply roller 11 Shaft 20 Elastic porous body block 21 Cylindrical elastic porous body 22 Shaft insertion hole 24 Projection 30 Jig 31 Frame 32 Resin sheet 40 Punching blade 43 Outer peripheral punching blade 44 Protrusion 47 Inner peripheral punching blade

Claims (1)

A cylindrical elastic porous body (21) is provided on the outer periphery of the shaft (11), and protrusions (24) are formed on the outer peripheral surface of the elastic porous body (21) with respect to the axis (a) of the elastic porous body. In the manufacturing method of the toner supply roller provided in a twisted state,
A twist compression step of rotating the elastic porous body block (20) made of urethane foam slab by rotating one end side thereof with respect to the other end side and compressing both ends of the elastic porous body block (20);
A cylindrical outer punching blade (a plurality of protrusions (44) formed by bending the outer peripheral surface outward at a predetermined interval between both ends of the elastic porous body block (20a) compressed in the twisted state ( 43) and an inner peripheral punching blade (47) having the same center as that of the outer peripheral punching blade (43) and having a smaller diameter than the outer peripheral punching blade (43), and releasing the twist and compression. A punching and twisting compression releasing step for obtaining a cylindrical elastic porous body (21) having a protrusion (24) twisted on the outer peripheral surface and having a shaft insertion hole (22) in the center;
A shaft insertion step of inserting the shaft (11) into the shaft insertion hole (22) of the cylindrical elastic porous body (21) and integrating the cylindrical elastic porous body (21) and the shaft (11);
A method for producing a toner supply roller, comprising:

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