JP2018155844A - Toner conveying roller and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner conveying roller that is excellent in toner supply property and toner scraping property to a developing roller, and a method with which the toner conveying roller can be manufactured easily at a low cost.SOLUTION: A toner conveying roller 10 comprises: a shaft 12; and an elastic layer 14 formed of resin foam on an outer periphery of the shaft 12. The density in a center part 14b in the longitudinal direction of the elastic layer 14 of the toner conveying roller 10 is higher than that of both ends 14a, 14b in the longitudinal direction of the elastic layer, and the entirety of the elastic layer 14 is formed of one foam resin.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a toner conveying roller used in an image forming apparatus such as a copying machine or a printer, and a manufacturing method thereof.

  Conventionally, the following processes have been adopted in image forming apparatuses such as copying machines and printers. That is, (1) the surface of the photoconductor (image forming body) is uniformly charged by a charging means such as a charging roller, and (2) an image is projected onto the photoconductor from an optical system having a laser irradiation unit or the like. A latent image is formed by erasing the charge of the exposed part of the body, and (3) a toner image is formed by supplying toner to the latent image of the photoreceptor by a developing roller, and (4) the toner image. Is transferred to the recording medium by transfer means such as applying a charge from the back of the recording medium such as paper, and (5) the toner image of the transferred recording medium is fixed by fixing means such as heat and pressure, This is a process for forming a print image.

  In such a process, the mechanism (development mechanism) for forming the toner image (3) is, for example, as shown in FIG. 5, a development that faces the photosensitive drum 3 that holds the latent image so as to be in contact with or close to it. This is performed by a mechanism that includes a roller 2 and a toner conveying roller 1 that is disposed so as to be in contact with or close to the developing roller 2 and to be in contact with a toner reservoir in the toner cassette.

  In the mechanism of FIG. 5, when each roller rotates in the direction of the arrow, the toner 5 is transported by the toner transport roller 1 and supplied to the surface of the developing roller 2. The toner 5 is thinned uniformly by the stratification blade 4. When the developing roller 2 having a thin layer of toner 5 on the surface rotates in contact with or close to the photosensitive drum 3, the toner 5 adheres to the latent image on the photosensitive drum 3 and a toner image is formed (developed).

  As described above, the toner transport roller transports the toner from the toner reservoir and supplies it to the developing roller, and scrapes and collects the toner remaining on the surface of the developing roller without being used for development. As the toner conveying roller, a roller having an elastic foam layer on the surface is generally used. The toner transportability, toner supply performance, and scraping performance of the toner transport roller are important performances for obtaining a high quality toner image in the developing mechanism, and the development of toner transport rollers having excellent performance has been promoted. It has been.

JP 2003-103535 A

  In the development step described above, when the toner transport roller supplies toner to the development roller, the toner transport roller is pressed against the development roller with a constant nip width (contact width of the two rollers). At this time, it is known that the shaft of the toner transport roller is bent, and the pressing force of the toner transport roller tends to be weaker at the center than at the longitudinal end of the developing roller. In this case, the toner supply property and scraping property of the toner conveying roller may be different between the longitudinal end portion and the longitudinal center portion of the developing roller, so that the image quality may be deteriorated. In particular, in recent years, image quality requirements have increased, and a toner transport roller that does not cause such problems is desired.

  In order to solve this problem, Patent Document 1 discloses that an elastic layer is formed using a composition that is a low-level foamed elastic body and a composition that is a high-hardness foamed elastic body, so that the central portion in the longitudinal direction is high. There has been proposed a foamed elastic member (toner conveying roller) having a hardness that is lower as it is closer to both ends in the longitudinal direction. However, since the elastic layer is formed by using the two foamed resin forming compositions, a boundary is formed between the respective portions, and due to this, sufficient toner supply property and scraping property can be obtained. There is a problem that becomes difficult. In addition, when two foamed resin forming compositions are used, the manufacturing cost increases and the manufacturing process becomes complicated.

  Accordingly, an object of the present invention is to provide a toner transport roller that is excellent in toner supply performance and toner scraping performance to the developing roller, and a method that can easily manufacture the toner transport roller at low cost.

  The object is to provide a toner conveying roller having a shaft and an elastic layer formed of foamed resin on the outer periphery of the shaft, wherein the density of the central portion in the longitudinal direction of the elastic layer is equal to both ends in the longitudinal direction of the elastic layer. The elastic layer is achieved by a toner conveying roller characterized in that the elastic layer is entirely formed of one foamed resin.

  As a result, when the toner transport roller is pressed against the developing roller, even if the shaft of the toner transport roller is bent, the pressing force of the toner transport roller against the longitudinal end portion of the developing roller and the pressing force against the central portion in the longitudinal direction. The difference from the pressure can be reduced. In addition, if two or more foamed resin forming compositions are foamed to form a high-density part and a low-density part in order to form a part having a different density in the elastic layer, at the boundary part, As a result, the toner supply property and the toner scraping property of the toner conveying roller may be lowered. However, in the present invention, since the entire elastic layer is formed of one foamed resin, such a problem does not occur.

  Preferred embodiments of the toner conveying roller of the present invention are as follows.

(1) The central portion in the longitudinal direction of the elastic layer is compressed in the longitudinal direction more than both longitudinal end portions of the elastic layer.
(2) Both ends in the longitudinal direction of the elastic layer are extended in the longitudinal direction from the central portion in the longitudinal direction of the elastic layer.
(3) The axial center part of the shaft and the longitudinal center part of the elastic layer are bonded via an adhesive layer.

  Another object of the present invention is a method for manufacturing a shaft and a toner conveying roller having an elastic layer on the outer periphery of the shaft, and the shaft is inserted into an elastic foam formed entirely from a single foamed resin. A shaft insertion step of forming an elastic layer on the outer periphery of the shaft, and the longitudinal direction of the elastic layer so that the density of the central portion in the longitudinal direction of the elastic layer is higher than both longitudinal ends of the elastic layer. Compression / extension including compression processing for compressing the central portion from both longitudinal end portions of the elastic layer and / or stretching processing for extending both longitudinal end portions of the elastic layer from the longitudinal central portion of the elastic layer It is achieved by a method for manufacturing a toner conveying roller and a method for manufacturing a toner conveying roller, including steps.

  According to this manufacturing method, since the elastic foam formed entirely from one foamed resin is used, the manufacturing cost is reduced correspondingly, and the manufacturing process is simplified.

The preferable aspect of the manufacturing method of the roller of this invention is as follows.
(1) The compression is performed in the longitudinal direction of the elastic layer.
(2) The extension is performed in the longitudinal direction of the elastic layer.
(3) Before the shaft insertion step, the method includes a step of applying an adhesive to the outer peripheral surface of the axial central portion of the shaft, and the axial central portion of the shaft and the elasticity through the adhesive in the compressed state The layer is adhered to the longitudinal center.

  ADVANTAGE OF THE INVENTION According to this invention, the toner conveyance roller excellent in the toner supply property and toner scraping property with respect to a developing roller, and the method which can manufacture this toner conveyance roller easily at low cost can be provided.

FIG. 3 is a schematic perspective view illustrating an example of a toner transport roller of the present invention. It is explanatory drawing which shows an example of the manufacturing method of the toner conveyance roller of this invention. It is explanatory drawing which shows the other example of the manufacturing method of the toner conveyance roller of this invention. It is explanatory drawing which shows the further another example of the manufacturing method of the toner conveyance roller of this invention. FIG. 6 is an explanatory diagram of a toner conveyance roller.

  Hereinafter, embodiments of the toner conveying roller of the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view showing a typical example of the toner conveying roller of the present invention. As illustrated, the toner conveying roller 10 of the present invention has a shaft 12 and an elastic layer 14 on the outer periphery thereof. The entire elastic layer 14 is made of a single foamed resin, and the density of the central portion 14b in the longitudinal direction of the elastic layer 14 is higher than the density of both end portions 14a and 14c in the longitudinal direction of the elastic layer 14.

  As described above, when the density of the elastic layer is the same in the entire roller portion, when the toner conveying roller is pressed against the developing roller, the shaft of the toner conveying roller is bent, and the pressing force against the central portion in the longitudinal direction of the developing roller is It tends to be lower than the pressing force against the direction end. According to the toner conveying roller 10 of the present invention, even when the shaft 12 is bent when the toner conveying roller 10 is pressed against the developing roller, the pressing force against the end portion in the longitudinal direction of the developing roller and the central portion in the longitudinal direction The difference in the pressing force with respect to can be reduced. This is because by making the density of the longitudinal central portion 14b of the elastic layer 14 higher than the longitudinal end portions 14a and 14c, the elastic modulus of the longitudinal central portion 14b becomes relatively high and the difference in pressing force is small. It is considered to be.

  As described above, the entire elastic layer 14 of the toner conveying roller 10 of the present invention is formed of one foamed resin. For example, when two or more materials are foamed to form a high-density part and a low-density part in order to form a part having a different density in one elastic layer, the boundary part causes the toner. Although the toner supply property and toner scraping property of the transport roller may be lowered, in the present invention, such a problem does not occur because the entire elastic layer is formed from one foamed resin. Therefore, the toner conveying roller 10 of the present invention has more excellent toner supply property and toner scraping property.

  In the present invention, the longitudinal central portion 14b of the elastic layer 14 is compressed in the longitudinal direction more than the longitudinal end portions 14a, 14c, so that the density of the longitudinal central portion 14b of the elastic layer 14 is the longitudinal end portions 14a. 14c is preferably higher than the density of 14c. In this case, the shape of the bubbles in the longitudinal central portion 14b of the elastic layer 14 is flat in the vertical direction (radial direction). As a result, air bubbles near the outer peripheral surface of the elastic layer 14 do not need to be crushed, so that further excellent toner supply properties and toner scraping properties can be obtained.

  In the present invention, the longitudinal end portions 14a and 14c of the elastic layer 14 are extended in the longitudinal direction relative to the longitudinal central portion 14b, so that the density of the longitudinal central portion 14b of the elastic layer 14 is longitudinal. It is also advantageous that it is higher than the density of the ends 14a, 14c. In this case, the shape of the bubbles at both ends 14a and 14b in the longitudinal direction of the elastic layer 14 is flat in the lateral direction (longitudinal direction).

In the toner conveying roller 10 of the present invention, the density ratio (D _b / D) of the density (D _b ) of the longitudinal central portion 14 b of the elastic layer 14 to the density (D _ac ) of the longitudinal ends 14 a, c of the elastic layer 14. _ac ) is preferably 104 to 126%. If the density ratio (D _b / D _ac ) in this range, the difference between the pressing force of the toner conveying roller on the longitudinal end of the developing roller and the pressing force on the longitudinal central portion can be further reduced. Furthermore, the image quality can be improved.

The lengths of the longitudinal ends 14a, 14c of the elastic layer 14 are preferably in the range of 50 mm from the longitudinal ends 14a, 14c, respectively, and the density (D _ac ) of the longitudinal ends 14a, 14c of the elastic layer 14 is The average density in that range. The length of the central portion 14b in the longitudinal direction of the elastic layer 14 is preferably in the range of 50 mm with the center in the longitudinal direction being the center, and the density (D _b ) of the central portion 14b in the longitudinal direction of the elastic layer 14 is the average density in that range. is there.

  You may comprise the density of the elastic layer 14 so that it may become high gradually as it goes to a longitudinal direction center from a longitudinal direction both ends. Further, one or a plurality of other regions are provided between the longitudinal center portion 14b of the elastic layer 14 and the longitudinal end portions 14a and 14c, and the elastic layer 14 is stepped from both longitudinal ends toward the center. Alternatively, the density may be increased.

  In the present invention, “the entire elastic layer is formed of one foamed resin” means that the elastic layer is not a foamed resin produced using two or more foamed resin forming compositions, but one It means that the foamed resin forming composition is produced by foaming. There is no restriction | limiting in particular in the kind for foamed resin formation composition and the foamed resin itself formed by this. Examples of the elastic foam that forms the elastic layer include polyurethane foam, silicone rubber foam, ethylene propylene rubber foam, acrylonitrile butadiene rubber foam, and the like. Of these, polyurethane foam is preferred. The foam structure may be open-celled or closed-celled.

  The polyurethane material for forming the polyurethane foam is not particularly limited as long as it contains a urethane bond in the resin. As the polyol component, known ones can be used. For example, polyether polyol, polytetramethylene ether glycol, THF-alkylene oxide copolymer polyol, polyester polyol, acrylic polyol, polyolefin polyol, ethylene-vinyl acetate copolymer A partially saponified product of a coalescence, a phosphate-based polyol, a halogen-containing polyol, or the like can be preferably used. As the isocyanate component, known components can be used, and commonly used TDI, MDI, crude-MDI (polymeric MDI), modified MDI, and the like can be used.

  In the polyurethane material, in addition to these polyurethane raw materials, a crosslinking agent, a foaming agent (water, low-boiling substances, gas bodies, etc.), a surfactant, a catalyst, etc. can be added as desired. It can be a structure. In addition, known additives such as flame retardants, fillers, and crosslinking agents may be used as appropriate. In order to impart conductivity to the toner transport roller, a known conductive agent such as an ionic conductive agent or an electronic conductive agent may be blended. Examples of ionic conductive agents include tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium (eg, lauryltrimethylammonium), hexadecyltrimethylammonium, octadecyltrimethylammonium (eg, stearyltrimethylammonium), benzyltrimethylammonium, modified fatty acid dimethylethyl Perchlorates such as ammonium, chlorates, hydrochlorides, bromates, iodates, borofluorides, sulfates, ethyl sulfates, carboxylates, ammonium salts such as sulfonates, lithium, Perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, trifluoromethyl of alkali metals and alkaline earth metals such as sodium, potassium, calcium and magnesium Sulfate, and sulfonic acid salts. Examples of the electronic conductive agent include conductive carbon such as ketjen black and acetylene black; carbon for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT; for ink subjected to oxidation treatment Examples thereof include carbon, pyrolytic carbon, natural graphite, and artificial graphite; conductive metal oxides such as tin oxide, titanium oxide, and zinc oxide; metals such as nickel, copper, silver, and germanium.

  There is no limitation on the method of obtaining the foam constituting the roller using the polyurethane material, and there are known methods such as a method of chemically foaming using the foaming agent and a method of foaming by mechanically entraining air during molding. It can be appropriately selected and used.

  The material of the shaft 12 in the toner transport roller 10 of the present invention is not particularly limited. For example, a solid or hollow shaft material made of a metal such as iron, stainless steel, or aluminum, or a resin such as hard plastic can be used. In particular, a shaft material made of conductive metal or conductive plastic is preferable.

  The method for producing the toner conveying roller of the present invention is not particularly limited as long as the above characteristics can be imparted to the elastic layer. In order to easily manufacture the toner conveying roller of the present invention, for example, the following method can be used.

  2A to 2D are schematic cross-sectional views for explaining a typical example of the method for producing a toner conveying roller of the present invention. Fig.2 (a) is a schematic sectional drawing which shows the elastic foam 14n used as an elastic layer. The elastic foam 14 is formed with a hole 15 for inserting a shaft, which will be described later. The diameter of the hole 15 of the elastic foam 14n is the same as or smaller than the diameter of the shaft to be inserted. When it is formed small, tackiness between the shaft and the elastic layer increases, and it becomes easy to maintain a desired density.

  Next, a process of inserting the shaft through the hole 15 of the elastic foam 14n is performed. FIG. 2B shows a state where the shaft 12 is inserted through the elastic foam 14n. Before the shaft 12 is inserted, the elastic foam 14n is compressed in the longitudinal direction. An adhesive 16 (preferably a hot melt adhesive) is applied to the surface of the central portion of the shaft 12. The compressed state is maintained using a fixing member (not shown) such as a fastener.

  Next, heating is performed in this state, that is, in a state where the shaft 12 is inserted into the compressed elastic foam 14. FIG.2 (c) has shown the state which is heating the elastic foam 14n by which the shaft 12 was penetrated using the oven 100 as a heating means. By heating, the portion where the adhesive 16 of the shaft 12 is applied and the corresponding portion of the elastic foam 14n are fixed. The heating temperature can be appropriately adjusted depending on the material of the elastic foam 14n. In the case of polyurethane foam, 150 to 250 ° C. is preferable. The heating means may be any means and is not limited to an oven.

  Next, it is taken out from the oven 100 and the compression maintaining state is released. FIG. 2D is a cross-sectional view of the state where the compression maintaining state is released. As shown in the figure, when the compression maintaining state is released, only the longitudinal center portion 14b of the elastic layer 14 is maintained in a compressed state, and both longitudinal end portions 14a and 14c are returned to the uncompressed state. Thereby, an elastic layer can be formed in which the density of the central portion 14b in the longitudinal direction of the elastic layer 14 is higher than the density of both end portions 14a and 14c in the longitudinal direction of the elastic layer 14. The heated elastic layer 24 may be polished.

  As described above, in the toner transport roller 10 thus manufactured, the central portion 14a in the longitudinal direction of the elastic layer 14 is compressed in the longitudinal direction, and the bubbles in the compressed portion become flat in the vertical direction. There may be another layer such as a rubber layer between the shaft 11 and the elastic layer 14. In the method for producing the toner conveying roller of the present invention described above, it is not necessary to form the composition from two or more kinds of foamed resin forming compositions, so that the production process is simplified correspondingly.

  Next, another example of the method for producing the toner conveying roller of the present invention will be described. FIG. 3A is the same as FIG. 2A and shows an uncompressed / non-expanded elastic foam 24 n having a hole 25. FIG. 3B is a schematic cross-sectional view showing a state where the shaft 22 is inserted through the elastic foam 24n. In this example, the adhesive 26 is applied to the entire outer surface of the shaft 22 in contact with the elastic layer 24n. And the longitudinal direction center part 24b is made into the state compressed to the longitudinal direction among the elastic foams 24n, and this state is maintained using fixing members, such as a fastener, as the state which does not compress the longitudinal direction both ends 24a and 24c. .

  FIG. 3C shows a heating step, and heating is performed in the same manner as in the case shown in FIG. FIG.3 (d) is a figure of the state which finished the heating process. As shown in the figure, the elastic layer 24 has a longitudinal central portion 24a compressed in the longitudinal direction, so that the elastic layer 24 has an elastic layer in which the density of the longitudinal central portion 24b is higher than the longitudinal end portions 24a and 24c. It is formed. In this example, since the adhesive is applied not only to the surface in the axial center of the shaft 22 but also to the both ends in the longitudinal direction, the adhesion between the shaft 22 and the elastic layer 24 is further improved. In the toner transport roller 20 thus manufactured, the bubbles in the longitudinal center portion 24a of the elastic layer 24 compressed in the longitudinal direction are flat in the longitudinal direction (radial direction).

  The heated elastic layer 24 may be polished. Further, one or a plurality of other regions are provided between the longitudinal center portion 14b of the elastic layer 14 and the longitudinal end portions 14a and 14c, and the elastic layer 14 is stepped from both longitudinal ends toward the center. Alternatively, the density may be increased.

  Next, still another example of the method for manufacturing the toner conveying roller of the present invention will be described. FIG. 4A shows an elastic foam 34 n in a non-compressed / non-extended state having a hole 35. FIG. 4B is a schematic cross-sectional view showing a state where the shaft 32 is inserted through the elastic foam 34n. In this example, the adhesive 36 is applied to the entire portion of the surface of the shaft 34 that contacts the elastic layer 34n. Then, in the elastic foam 34n, the longitudinal ends 34a and 34c are extended in the longitudinal direction, and the longitudinal central portion 34b is not expanded, and this state is maintained using a fixing member such as a fastener. To do.

  FIG. 4C shows the heating process. Similarly to the heating method described in FIG. 2C, the elastic foam 34n through which the shaft 32 is inserted as shown in FIG. 4B is heated. FIG.3 (d) is a figure of the state which finished the heating process. As shown in the drawing, the longitudinal end portions 34a and 34c of the elastic layer 34 are extended in the longitudinal direction, so that the density of the longitudinal center portion 34b of the elastic layer 34 is higher than that of the longitudinal end portions 34a and 34c. Layer 34 is formed. In the toner transport roller 10 thus manufactured, the bubbles at both longitudinal ends 34a and 34c of the elastic layer 34 elongated in the longitudinal direction are flattened in the lateral direction. The heated elastic layer 24 may be polished.

  In the three examples of the toner conveying roller manufacturing method described above, elastic foam formed from one foamed resin forming composition is used without using two or more kinds of foamed resin forming compositions as in the prior art. Since the body is used, the manufacturing cost is reduced correspondingly, and the manufacturing process is simplified.

  In addition, this invention is not limited to the structure and Example of said embodiment, A various deformation | transformation is possible within the range of the summary of invention.

10, 20, 30 Toner conveying rollers 12, 22, 32 Shafts 14, 24, 34 Elastic layers 14n, 24n, 34n Elastic foams 16, 26, 36 Adhesive 100 Oven

Claims (8)

A toner conveying roller having a shaft and an elastic layer formed of foamed resin on an outer periphery of the shaft,
The density of the longitudinal center part of the elastic layer is higher than both longitudinal ends of the elastic layer,
The toner conveying roller according to claim 1, wherein the elastic layer is entirely formed of one foamed resin.   The toner conveying roller according to claim 1, wherein a central portion in the longitudinal direction of the elastic layer is compressed in a longitudinal direction relative to both longitudinal end portions of the elastic layer.   The toner conveying roller according to claim 1, wherein both end portions in the longitudinal direction of the elastic layer are extended in a longitudinal direction from a central portion in the longitudinal direction of the elastic layer.   The toner conveyance roller according to claim 1, wherein an axial center portion of the shaft and a longitudinal center portion of the elastic layer are bonded via an adhesive layer. A method of manufacturing a toner conveying roller having a shaft and an elastic layer on the outer periphery of the shaft,
A shaft insertion step in which the shaft is inserted into an elastic foam formed entirely from one foamed resin, and an elastic layer is formed on the outer periphery of the shaft, and the density of the central portion in the longitudinal direction of the elastic layer is determined by the elastic layer Compression treatment for compressing the longitudinal center portion of the elastic layer so as to be higher than both longitudinal end portions of the elastic layer, and / or the longitudinal end portions of the elastic layer. A method for manufacturing a toner conveying roller, comprising a compression / extension step including an extension process that extends from a longitudinal center of an elastic layer.   The manufacturing method according to claim 5, wherein the compression is performed in a longitudinal direction of the elastic layer.   The manufacturing method according to claim 5, wherein the extension is performed in a longitudinal direction of the elastic layer.   Before the shaft insertion step, the method includes a step of applying an adhesive to the outer peripheral surface of the axial central portion of the shaft, and the axial central portion of the shaft and the length of the elastic layer via the adhesive in the compressed state The manufacturing method of any one of Claims 5-7 which adhere | attach a direction center part.

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