JP2012088630A - Sponge roll for electrophotographic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sponge roll for an electrophotographic apparatus, the roll capable of improving toner scraping performance and reducing a stress imparted to the toner.SOLUTION: The sponge roll 10 for an electrophotographic apparatus includes a shaft body 12 and a single sponge elastic layer 14 formed on an outer circumference of the shaft body 12. The sponge elastic layer 14 satisfies (hardness in a surface portion 14c)<(hardness in an inner portion 14d). The hardness distribution of the sponge elastic layer 14 can be imparted by impregnating cells 14a of the inner portion 14d with an impregnation component 15a or by modifying a material that forms the surface portion 14c. The sponge roll 10 can be suitably used for supplying toner or for cleaning.

Description

  The present invention relates to a sponge roll for electrophotographic equipment, and more particularly to a sponge roll for electrophotographic equipment suitable for use in toner supply rolls, cleaning rolls and the like of electrophotographic equipment such as copying machines, printers and facsimiles. .

  In general, copying in an electrophotographic apparatus is performed as follows. As shown in FIG. 7, the toner 102 in the toner box 100 is supplied to the surface of the developing roll 106 via the toner supply roll 104, and this toner 102 is further rubbed between the developing roll 106 and the toner layer forming blade 108. Charge by charging. Then, a charged toner 102 is attached to the electrostatic latent image formed on the surface of the photosensitive drum 112 by the charging roll 110 to form a toner image, which is passed through the transfer unit 114, thereby being transferred onto the copy paper 116. To transfer and fix.

  The toner 102 remaining on the surface of the developing roll 106 without being attached to the electrostatic latent image is scraped off by the toner supply roll 104, collected in the toner box 100, and reused. Further, the toner 102 remaining on the surface of the photosensitive drum 112 is scraped off by the cleaning roll 118, and the surface of the photosensitive drum 112 is cleaned.

  The toner supply roll and the cleaning roll usually have a shaft body and a sponge elastic layer formed on the outer periphery of the shaft body. The sponge elastic layer of this type of sponge roll is required to have a toner scraping performance for reliably scraping off the toner remaining on the surface of the mating member such as the developing roll and the photosensitive drum. This is because preventing toner filming on the developing roll and the photosensitive drum by improving the toner scraping performance is advantageous for improving the durability of the electrophotographic apparatus.

  Patent Document 1 discloses a technique in which the surface of a polyurethane foam layer formed on the outer periphery of a core metal is formed into a concavo-convex structure in order to improve toner scraping performance.

  In addition, as a method for improving the toner scraping performance, for example, a method of increasing the hardness of the sponge elastic layer is also known.

Japanese Patent No. 3536598

  However, the conventionally known techniques have the following problems.

  That is, in order to form a concavo-convex structure on the surface of the sponge elastic layer, a molding die having a concavo-convex structure corresponding thereto must be used, and there is a difficulty in that a mold manufacturing cost is required. Further, when applied to an electrophotographic apparatus with a reduced toner conveyance amount, the uneven structure on the surface of the sponge elastic layer may be transferred to the formed image.

  On the other hand, the technique of increasing the hardness of the sponge elastic layer is not an effective measure because stress applied to the toner increases and toner deterioration is accelerated.

  The present invention has been made in view of the above circumstances, and the problem to be solved by the present invention is to provide a sponge roll for an electrophotographic apparatus capable of improving toner scraping performance and reducing stress applied to the toner. There is to do.

  In order to solve the above problems, a sponge roll for electrophotographic equipment according to the present invention has a shaft body and a single sponge elastic layer formed on the outer periphery of the shaft body, and the sponge elastic layer has a surface portion. The gist is to satisfy the hardness of <the internal hardness.

  Here, it is preferable that the inside of the sponge elastic layer is harder than the surface portion due to the impregnated component impregnated in the cell inside.

  At this time, the sponge elastic layer has a water repellent component attached to the cell inner wall surface of the surface portion, and the inner cell is impregnated with a water-based impregnating component so that the inner portion is more than the surface portion. It is preferable to be formed hard.

  In the sponge roll for electrophotographic equipment according to the present invention, the sponge elastic layer may be formed so that the surface portion is more flexible than the inside by modifying the material forming the surface portion. good.

  In this case, the modification is preferably decomposition of the material forming the surface portion.

  The sponge roll for electrophotographic equipment according to the present invention has a shaft body and a single sponge elastic layer formed on the outer periphery of the shaft body, and the sponge elastic layer has a surface portion hardness <an internal hardness. Fulfill. According to the sponge roll, since the surface portion of the sponge elastic layer is more flexible than the inside, the sponge elastic layer hardly applies stress to the toner, and toner deterioration can be suppressed. In addition, since the inside of the sponge elastic layer is harder than the surface portion, it is appropriate when a counterpart member such as a developing roll is pressed against the sponge elastic layer without forming an uneven structure on the roll surface as in the prior art. Hardness can be exhibited and toner scraping performance can be improved.

  Here, when the inside of the sponge elastic layer is impregnated with the impregnated component so that the inside is harder than the surface portion, another layer is coated on the sponge elastic layer to form a two-layer structure. Even if a technique such as the above is not adopted, a predetermined hardness distribution is provided in the sponge elastic layer. Therefore, it becomes easy to improve the toner scraping performance and reduce the stress applied to the toner with a single sponge elastic layer.

  At this time, the water repellent component adheres to the cell inner wall surface of the surface portion of the sponge elastic layer, and the cell inside the sponge elastic layer is impregnated with the water-based impregnation component, so that the interior is harder than the surface portion. If it is, it becomes easier to satisfy the hardness of the surface portion <the internal hardness. In addition, since an aqueous impregnation component is used, it is easy to handle and environmentally friendly.

  In addition, when the material forming the surface portion of the sponge elastic layer is modified so that the surface portion is formed more flexibly than the inside, another layer is coated on the sponge elastic layer, and two layers are formed. Even without adopting a method such as a structure, a predetermined hardness distribution is imparted in the sponge elastic layer. In addition, a predetermined hardness distribution is given in the sponge elastic layer regardless of the cell structure (independent cell, communication cell) of the sponge elastic layer. Therefore, it becomes easy to improve the toner scraping performance and reduce the stress applied to the toner with a single sponge elastic layer.

  The sponge roll for electrophotographic equipment according to the present invention can be suitably used as a toner supply roll, a cleaning roll, etc. in electrophotographic equipment.

It is a circumferential direction sectional view of the sponge roll concerning the present invention. It is the figure which expanded and showed the example of the sponge elastic layer typically. It is the figure which expanded and showed other examples of the sponge elastic layer typically. It is a figure for demonstrating the method to measure the pushing displacement of a sponge elastic layer, and the load at the time of pushing. It is the figure which showed typically the relationship between the indentation displacement X (mm) of a sponge elastic layer, and the indentation load P (gf) about the sponge roll which concerns on this invention. It is the figure which showed the relationship between the pushing displacement X (mm) of a sponge elastic layer, and the load P (gf) at the time of pushing about the sponge roll which concerns on Example 1 and Comparative Example 1. FIG. It is a figure for demonstrating the general copying principle in an electrophotographic apparatus.

  Hereinafter, the sponge roll for electrophotographic equipment according to the present embodiment (hereinafter abbreviated as “sponge roll”) will be described.

  FIG. 1 is a circumferential sectional view of a sponge roll. As shown in FIG. 1, the sponge roll 10 includes a shaft body 12 and a single sponge elastic layer 14 formed on the outer periphery of the shaft body 12.

  The shaft body 12 may be solid or hollow. Examples of the material for forming the shaft body 12 include metals such as iron, stainless steel, aluminum, and iron plated, or polyacetal (POM), acrylonitrile-butadiene-styrene copolymer. Examples thereof include plastics such as coalescence (ABS), polycarbonate, and polyamide. In addition, an adhesive, a primer, or the like may be applied to the outer peripheral surface of the shaft body 12 as necessary.

  As a material for forming the sponge elastic layer 14, a polyurethane foam obtained by combining a polyol component and an isocyanate component used in the production of a flexible polyurethane foam can be suitably used.

  Examples of the polyol component include polyolefin polyols such as polyether polyol, polyester polyol, polybutadiene polyol, and polyisobutylene polyol. These may be used alone or in combination of two or more.

  The isocyanate component is not particularly limited as long as it is a bifunctional or higher polyisocyanate. For example, 2,4- (or 2,6-) tolylene diisocyanate (TDI), orthotoluidine diisocyanate (TODI), naphthylene diisocyanate. (NDI), xylylene diisocyanate (XDI), 4,4'-diphenylmethane diisocyanate (MDI), carbodiimide-modified MDI, polymethylene polyphenyl isocyanate, polymeric polyisocyanate and the like. These may be used alone or in combination of two or more.

  Furthermore, in addition to the polyol component and the isocyanate component, a crosslinking agent, a foaming agent (water, low-boiling substances, gas bodies, etc.), a surfactant, a catalyst, a flame retardant, a filler, and a conductivity-imparting agent as necessary. An antistatic agent or the like can be appropriately blended.

  FIG. 2 is an enlarged view schematically showing an example of the sponge elastic layer. FIG. 3 is an enlarged view schematically showing another example of the sponge elastic layer. The sponge elastic layer 14 is formed of a large number of cells 14a, and each cell 14a includes a cell skeleton 14b. Each cell 14a may be communicated as shown in FIG. 2, or may be independent as shown in FIG. When the cells 14a communicate with each other, toner movement inside the sponge elastic layer 14 is facilitated, and therefore there is an advantage that clogging of the cells 14a due to toner can be reduced.

  In addition, many openings of the cells 14 a are distributed on the outer peripheral surface of the sponge elastic layer 14. The opening diameter of the opening is set within a range of approximately 100 to 800 μm, although it depends on the size of the toner used.

  Here, the sponge elastic layer 14 has a surface portion 14c and an inner portion 14d. The surface portion 14c is a portion in the vicinity of the surface of the sponge elastic layer 14, and mainly contributes to alleviating toner stress. On the other hand, the inner part 14d is a part located closer to the shaft body 12 than the surface part 14c, and mainly contributes to improvement in toner scraping property.

  The maximum pressing depth of the mating member such as the developing roll with respect to the sponge roll 10 is about 0.5 to 2 mm. Since the maximum indentation depth is related to the toner scraping performance, the surface portion 14c that contributes to alleviating toner stress is designed to exist in a region shallower than the maximum indentation depth. The region where the surface portion 14c is present may be present in the range below the maximum indentation depth from the surface of the sponge elastic layer 14, more preferably in the range of 30 to 80% of the maximum indentation depth.

  Here, the sponge elastic layer 14 satisfies the hardness of the surface portion 14c <the hardness of the inner portion 14d. Therefore, the surface portion 14c of the sponge elastic layer 14 becomes softer than the inside 14d, and the sponge elastic layer 14 hardly applies stress to the toner, so that toner deterioration can be suppressed. In addition, since the inside 14d of the sponge elastic layer 14 is harder than the surface portion 14c, it can exhibit an appropriate hardness when a counterpart member such as a developing roll is pressed against the sponge elastic layer 14 and improves the toner scraping performance. Can be made.

  FIG. 4 is a view for explaining a method of measuring the indentation displacement of the sponge elastic layer and the load at the time of the indentation. As shown in FIG. 4A, the sponge roll 10 is supported at both end portions of the shaft body 12, and the jig 20 having a plate-like pressing surface (50 mm × 50 mm, thickness 7 mm) is pushed into the sponge elastic layer 14. The indentation speed is 10 mm / min. Thereby, the relationship between indentation displacement X (mm) and the load P (gf) at the time of indentation can be calculated | required. However, as shown in FIG. 4 (b), the above measurement is performed at a total of 8 measurement points of 2 locations in the axial direction (width direction) × 4 locations every 90 ° in the roll circumferential direction, and the average value is obtained.

  FIG. 5 schematically shows the relationship between the indentation displacement X (mm) of the sponge elastic layer and the indentation load P (gf) for the sponge roll according to the present invention. In FIG. 5, A shows the relationship between the indentation displacement X (mm) of the sponge elastic layer 14 and the indentation load P (gf) in the sponge roll 10 according to the present invention. B is shown for comparison, and shows the relationship between the indentation displacement X (mm) of the sponge elastic layer and the indentation load P (gf) in a conventional sponge roll having a uniform sponge elastic layer. . Xmax is the maximum indentation displacement, and Pmax is the maximum indentation load.

  As shown in FIG. 5, the conventional sponge roll has an upwardly convex curve B in a region where the indentation displacement X is relatively small. In contrast, the sponge roll 10 according to the present invention has a downward convex curve A in a region where the indentation displacement X is relatively small, and the indentation load P increases as the indentation displacement X becomes relatively large. Indicates. The reason why the curve behavior is different is that the sponge elastic layer 14 of the sponge roll 10 according to the present invention satisfies the hardness of the surface portion 14c <the hardness of the inner portion 14d.

  If the area of the triangle surrounded by the coordinates (0, 0), (Xmax, 0), (Xmax, Pmax) in FIG. 5 is S, and the integral value of the curve A from X = 0 to X = Xmax is S ′, The sponge elastic layer 14 preferably satisfies S ′ / S <1. More preferably, S ′ / S ≦ 0.98, and even more preferably, S ′ / S ≦ 0.95 is satisfied. As a result, since it is difficult to give stress to the toner, it is possible to suppress toner deterioration and to ensure toner scraping performance.

  In order to satisfy the hardness of the surface portion 14c <the hardness of the inner portion 14d, the sponge elastic layer 14 may be specifically configured as follows. Hereinafter, description will be made with reference to FIGS.

  In the sponge elastic layer 14 shown in FIG. 2, each cell 14a communicates. And the impregnation component 15a exists in the cell 14a of the inside 14d, and thereby the inside 14d is formed to be harder than the surface portion 14c. The impregnation component 15a may fill all of the cells 14a in the interior 14d or may not fill all of the cells 14a.

  Examples of the impregnation component 15a include acrylic resins such as polyacrylates and modified polyacrylates, acrylic acid-styrene copolymer resins, acrylic ester-styrene copolymer resins, acrylic acid-vinyl acetate copolymer resins, Various resins such as polyurethane, polyvinyl acetate, ethylene-vinyl acetate copolymer resin, polyester, polyamide, polyvinyl chloride, ethylene-propylene-diene copolymer rubber, isoprene rubber, chloroprene rubber, nitrile rubber, fluorine rubber, silicone Examples of the component mainly include various rubbers such as rubber. These may be contained alone or in combination of two or more. These components may or may not be cured. Preferably, it is preferably cured from the viewpoint of preventing contamination due to leakage of impregnated components during use. Preferably, when the sponge elastic layer 14 is formed of polyurethane, an impregnation component suitable for an aqueous dispersion can be suitably used among the above impregnation components from the viewpoint that polyurethane does not easily swell.

  In the sponge elastic layer 14 shown in FIG. 2, the water repellent component 15b is attached to the inner wall surface of the cell 14a of the surface portion 14c. In this case, when the water-based impregnation component 15a is impregnated from the surface of the sponge elastic layer 14, the impregnation component 15a does not remain in the cell 14a of the surface portion 14c, and the cell 14a of the inner 14d is immediately impregnated. Component 15a can be impregnated.

  Examples of the water-repellent component 15b include components such as paraffin, waxes, higher fatty acid esters, amide waxes, higher fatty acid metal salts, polyethylene, polyethylene oxide, silicon-based compounds, fluorine-based compounds, and more than the impregnated component 15a. A thing with low hardness etc. can be illustrated. These may be contained alone or in combination of two or more. These components may or may not be cured. Preferably, it is preferably cured from the viewpoint of preventing contamination due to leakage of water repellent components during use.

  On the other hand, in the sponge elastic layer 14 shown in FIG. 3, the surface portion 14c is formed more flexibly than the inside 14d by modifying the material forming the surface portion 14c. Therefore, the sponge elastic layer 14 shown in FIG. 3 does not require the impregnation component 15a and the water repellent component 15b to be present in the cell 14a. Therefore, although FIG. 3 illustrates the case where each cell 14a is independent, the present invention is not limited to this, and each cell 14a may communicate with each other.

  Examples of a method for flexibly modifying the surface portion 14c include a method of irradiating light having energy that decomposes the material forming the sponge elastic layer 14. More specifically, for example, when the material forming the sponge elastic layer 14 is polyurethane, the surface of the sponge elastic layer 14 is irradiated with ultraviolet rays to partially cut urethane bonds, thereby softening the vicinity of the surface. Thus, the surface portion 14c can be formed.

  The sponge roll 10 described above can be manufactured, for example, as follows. That is, first, the shaft body 12 is loaded into a predetermined roll forming die. This roll forming die is composed of a cylindrical shape having a length substantially equal to the length of the sponge elastic layer 14 in the axial direction, and a cap that closes both ends of the cylindrical shape. A forming cavity that is supported coaxially with the cylindrical shape by the cap and gives the final roll shape of the target sponge row 10 is formed in the cylindrical shape.

  Then, a material for forming the sponge elastic layer 14 (polyurethane foam composition or the like) is injected into the molding cavity of the mold, and the base sponge elastic layer is integrally formed around the shaft body by foaming and curing, and then removed. Type. In the base sponge elastic layer, the surface portion 14c and the inside 14d having different hardnesses are not yet formed.

  A base sponge elastic layer may be formed by cutting a roll material from a foam material of slab foaming or mold foaming, passing the shaft through it, and then polishing the surface.

  As shown in FIG. 2, in order to give each cell appropriate communication, for example, after removing the mold, the sponge roll 10 is rotated around the shaft body 12 and a high-pressure gas ( A gas such as air or nitrogen) is sprayed onto the base sponge elastic layer. As a result, the high-pressure gas diffuses into the base sponge elastic layer due to the resistance of the shaft body 12, the cell film between the foamed cells and the foamed cells is broken, and the cells can communicate with each other.

  In order to form the sponge elastic layer 14 shown in FIG. 2, a coating liquid containing the water repellent component 15b is formed in the vicinity of the surface of the base sponge elastic layer formed on the shaft body (for example, around 1 mm). Apply and dry and heat-treat as necessary. Examples of the coating method include, for example, a roll in which a base sponge elastic layer is formed on the coating film immediately after the coating liquid is applied on a smooth table to form an undried coating film with a predetermined thickness. Examples thereof include a method in which the body is moved while rotating and the coating liquid is adhered to the surface of the base sponge elastic layer.

  Thereafter, the sponge elastic layer 14 is impregnated in the coating liquid containing the impregnation component 15a up to about the entire roll or the shaft body 12. Thereby, the impregnation component 15a is not applied to the cell 14a to which the water repellent component 15b is adhered, and the impregnation component 15a is impregnated in the interior 14d. Then, if this roll is taken out from the coating liquid containing the impregnating component 15a and is squeezed, dried and heat-treated as necessary, the sponge roll 10 is obtained.

  On the other hand, in order to form the sponge elastic layer 14 shown in FIG. 3, the material is decomposed on the surface of the base sponge elastic layer formed on the shaft body 12 in accordance with the material for forming the base sponge elastic layer. By irradiating light having energy to cut, the chemical bond of the material near the surface of the base sponge elastic layer is cut and softened. As a result, the surface portion 14c is formed in the vicinity of the surface of the sponge elastic layer 14, and the portion where the material has not been decomposed is relatively harder than the decomposed portion, thereby forming the interior 14d. Thereby, the sponge roll 10 is obtained.

  The obtained sponge roll 10 can be suitably used as a toner supply roll, a cleaning roll, and the like.

  Hereinafter, the present invention will be described in detail using examples.

1. Production of sponge rolls according to examples and comparative examples (shaft body)
A SUM22 solid cylindrical shaft body having a diameter of 5 mm was prepared.

(Preparation of sponge composition for forming sponge elastic layer)
Polyether polyol (Mitsui Chemicals, EP-828, OH number = 28) 90 parts by weight, Polymer polyol (Mitsui Chemicals, POP-31-28, OH number = 28) 10 parts by weight, diethanolamine 2 parts by weight, silicon foam stabilizer (Nihon Unicar Co., Ltd., L-5309) 3 parts by weight, water 2 parts by weight, tertiary amine catalyst (Kao Co., Ltd., Kaulizer No. 31) 0.5 part by weight Parts, tertiary amine catalyst (Tosoh Co., Ltd., Toyocat HX-35) 0.1 parts by weight, dibutyltin dilaurate 0.1 parts by weight, and isocyanate (Sumitomo Bayer Urethane Co., Ltd., Sumijoule VT-) 80, NCO% = 45) 30.5 parts by weight were blended to prepare a sponge composition for forming a sponge elastic layer.

(Manufacture of various sponge rolls)
In the separately prepared pipe mold, the shaft body is arranged coaxially, both ends of the pipe mold are closed with caps and the shaft body is supported, and in this state, the sponge composition prepared in the molding cavity is prepared. A predetermined amount was injected, and foamed and cured under conditions of 60 ° C. × 30 minutes, and a roll body in which a base sponge elastic layer (thickness 5.5 mm) was integrally formed around the shaft body was produced. In addition, roll bodies (hereinafter sometimes referred to as “base rolls”) having different hardnesses of the base sponge elastic layer were produced by changing the amount of the sponge composition injected into the molding cavity.

Example 1
Silicone rubber coating solution (water-based, cured type, “KM-2002L-1” nonvolatile content 43%, manufactured by Shin-Etsu Chemical Co., Ltd.) is diluted with water so that the non-volatile content is 5%. A liquid was prepared. Next, this coating solution was adjusted to a coating thickness of 0.5 mm by a roll coating method, and applied to the surface of a base roll having a roll hardness of 110 gf. Next, the base roll was heat-treated at 130 ° C. for 30 minutes to cure the components, and a surface portion was formed on the base sponge elastic layer. Next, an acrylate latex (manufactured by Nippon Zeon Co., Ltd., “Nipol LX852”, non-volatile content 45%) was diluted with water so that the non-volatile content was 15%, to prepare an entire impregnation solution. Next, the entire impregnating solution was impregnated with the entire base roll after the heat treatment, and the cells inside the base sponge elastic layer were impregnated with the entire impregnating solution, followed by further drawing treatment. Next, the base roll was heat-treated at 130 ° C. for 30 minutes to cure the components, thereby forming a sponge elastic layer. Thereby, the sponge roll which concerns on Example 1 was produced.

(Example 2)
Silicone rubber-based coating liquid (water-based, cured type, “KM-2002L-1” non-volatile content 43%, manufactured by Shin-Etsu Chemical Co., Ltd.) is diluted with water so that the non-volatile content is 2%, and surface coating is performed. In the same manner as in Example 1 except that the liquid was prepared, and the coating liquid was adjusted to a coating thickness of 0.3 mm by the roll coating method, and applied to the base roll surface having a roll hardness of 72 gf. A sponge roll according to Example 2 was produced.

(Example 3)
Silicone rubber-based coating liquid (water-based, curing type, “KM-2002L-1” nonvolatile content 43%, manufactured by Shin-Etsu Chemical Co., Ltd.) is diluted with water so that the nonvolatile content is 10%, and surface coating is performed. In the same manner as in Example 1, except that the liquid was prepared, the coating liquid was adjusted to a coating thickness of 0.8 mm by the roll coating method, and applied to the surface of the base roll having a roll hardness of 72 gf. A sponge roll according to Example 3 was produced.

Example 4
Silicone coating solution (solvent type: IPA solvent, cured type, “KS7001” non-volatile content 21% made by Shin-Etsu Chemical Co., Ltd.) is diluted with IPA solvent so that the non-volatile content is 5%, and surface coating is performed. A liquid was prepared. Next, this coating solution was adjusted to a coating thickness of 0.3 mm by a roll coating method and applied to the surface of a base roll having a roll hardness of 110 gf. Next, the base roll was heat-treated at 130 ° C. for 30 minutes to cure the components, and a surface portion was formed on the base sponge elastic layer. Next, water-based urethane (manufactured by ADEKA, “Adekabon titer HUX-290H”, 62% nonvolatile content) was diluted with water so that the nonvolatile content was 20%, and an entire impregnation solution was prepared. Next, the entire impregnating solution was impregnated with the entire base roll after the heat treatment, and the entire impregnating solution was impregnated into the cells inside the base sponge elastic layer, and a drawing treatment was performed. Next, the base roll was heat-treated at 130 ° C. for 30 minutes to cure the components, thereby forming a sponge elastic layer. Thereby, a sponge roll according to Example 4 was produced.

(Example 5)
Fluororubber coating liquid (Daikin Industries, Ltd. “Daiel Latex GL-252E” and “Daiel Latex GL-200B” mixture, GL-252E: GL-200B so that the non-volatile content is 5%. = 100 parts by mass: 5 parts by mass) was diluted with water to prepare a surface coating solution. Next, this coating solution was adjusted to a coating thickness of 0.5 mm by a roll coating method and applied to the surface of a base roll having a roll hardness of 110 gf. Next, the base roll was heat-treated at 130 ° C. for 30 minutes to cure the components, and a surface portion was formed on the base sponge elastic layer. Next, water-based urethane (manufactured by ADEKA, “Adekabon titer HUX-290H”, 62% nonvolatile content) was diluted with water so that the nonvolatile content was 20%, and an entire impregnation solution was prepared. Next, the entire impregnating solution was impregnated with the entire base roll after the heat treatment, and the entire impregnating solution was impregnated into the cells inside the base sponge elastic layer, and a drawing treatment was performed. Subsequently, this base roll was heat-treated at 130 ° C. for 30 minutes to cure the components, thereby forming a sponge elastic layer. Thereby, a sponge roll according to Example 5 was produced.

(Example 6)
A lamp output of 80 / cm, a rated power of 4 kW, and a distance of 12 cm from an ultraviolet lamp near a wavelength of 280 nm, and the base roll (roll hardness of 171 gf) is covered so that the ultraviolet lamp is irradiated only on the surface of 1 mm. Then, ultraviolet rays were irradiated for 2 minutes while rotating (30 rpm) the arranged base roll, and the urethane bonds near the surface of the base sponge elastic layer were partially cut. Thereby, a sponge roll according to Example 6 was produced.

(Comparative Example 1)
The base roll (roll hardness 171 gf) was used as the sponge roll according to Comparative Example 1.

(Comparative Example 2)
The base roll (roll hardness 110 gf) was a sponge roll according to Comparative Example 2.

(Comparative Example 3)
An acrylate latex (manufactured by Nippon Zeon Co., Ltd., “Nipol LX852”, 45% non-volatile content) was diluted with water so that the non-volatile content was 15%, to prepare an entire impregnation solution. Next, the whole base roll having a roll hardness of 72 gf was impregnated in this whole impregnating liquid, and the whole impregnating liquid was impregnated in the cells of the base sponge elastic layer, and then a squeezing treatment was performed. Next, the base roll was heat-treated at 130 ° C. for 30 minutes to cure the components, thereby forming a sponge elastic layer. Thereby, a sponge roll according to Comparative Example 3 was produced.

2. Roll physical properties (hardness)
The hardness of the sponge elastic layer of the sponge roll according to the example and the comparative example was measured by the method shown in FIG. Specifically, the sponge roll is supported at both ends of the shaft body, and the sponge elastic layer is pressed at a speed of 10 mm / min with a jig having a plate-like pressing surface (50 mm × 50 mm, thickness 7 mm). The relationship between indentation displacement X (mm) and indentation load P (gf) was examined. In this test, the load P (gf) at the time of 1 mm displacement (compression) was set as the maximum pushing load. As a result, all the sponge rolls according to Examples 1 to 6 exhibited the same behavior as the curve A shown in FIG. On the other hand, all the sponge rolls according to Comparative Examples 1 to 3 showed the same behavior as the curve B shown in FIG. As a representative example, FIG. 6 shows the relationship between the indentation displacement X (mm) of the sponge elastic layer and the indentation load P (gf) measured for the sponge rolls according to Example 1 and Comparative Example 1. Further, the S ′ / S value described above was obtained from the relationship between the indentation displacement X (mm) and the indentation load P (gf). Further, the indentation load P (gf) at the time of 1 mm displacement (compression) when pressed at a speed of 10 mm / min was measured as roll hardness (gf). The roll hardness is an average value of 8 places in total, 2 places in the axial direction and 4 places in the roll circumferential direction of 90 °. The larger this value is, the harder the sponge elastic layer is.

3. Image Evaluation The following image evaluation was performed using each sponge roll as a toner supply roll.

(Ghost evaluation of copied images after initial and endurance)
The toner scraping property of each sponge roll as a toner supply roll was evaluated as follows. That is, a sponge roll was incorporated in a developing device of a commercially available printer, a predetermined image was output, and the obtained initial copy image was visually observed. A good image with no ghost was evaluated as “◯” because the initial toner scraping property was good. Although there were some ghosts, the slight ones were marked “△”. A case where a ghost of a level that is difficult to be put into practical use was present was evaluated as “x” because the initial toner scraping property was poor.

  Further, 10,000 character strings having a toner density of 5% were output. Thereafter, a predetermined image was produced, and the obtained copy image (durable copy image) was visually observed. Those having no ghost and good image were evaluated as “◯” because the toner scraping property after durability was good. Although there were some ghosts, the slight ones were marked “△”. Those having a level of ghosts that were difficult to put to practical use were evaluated as “x” because the toner scraping property after durability was inferior.

(Evaluation of toner filming of durable copy images)
The degree of stress applied to the toner by each sponge roll as the toner supply roll was evaluated as follows. That is, a sponge roll was incorporated in a developing device of a commercially available printer, and 10,000 character strings having a toner density of 5% were output. Thereafter, a predetermined image was produced, and the obtained copy image (durable copy image) was visually observed. An image having no image defects such as color loss due to toner filming and having a good image was evaluated as “◯” because the toner stress was sufficiently reduced. Although some image defects are recognized, minor ones are indicated as “Δ”. Those having image defects at a level that is difficult to put to practical use were evaluated as “x” because the stress on the toner was large.

  Table 1 summarizes the manufacturing conditions, roll physical properties, and image evaluation results when forming the sponge elastic layer.

  Table 1 shows the following. That is, since the sponge rolls according to Comparative Examples 1 to 3 are all hard in the vicinity of the surface of the sponge elastic layer, the toner tends to be stressed and image defects due to toner filming occur.

  On the other hand, as for the sponge roll which concerns on Examples 1-6, the surface part is formed in the depth of about 1 mm from the surface of a sponge elastic layer, and the lower part of a surface part is made into the inside. Then, the hardness of the surface portion <the internal hardness is satisfied. Therefore, it was confirmed that it is possible to improve both the toner scraping performance and the stress applied to the toner.

  The embodiments and examples of the present invention have been described above, but the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the spirit of the present invention. is there.

  For example, in the above embodiment, the sponge roll according to the embodiment is applied as a toner supply roll for evaluation, but it can also be applied as a cleaning roll.

DESCRIPTION OF SYMBOLS 10 Sponge roll 12 Shaft body 14 Sponge elastic layer 14a Cell 14b Cell skeleton part 14c Surface part 14d Interior 15a Impregnation component 15b Water repellent component

Claims (5)

A shaft body and a single sponge elastic layer formed on the outer periphery of the shaft body;
The sponge elastic layer is a sponge roll for electrophotographic equipment, wherein the hardness of the surface portion <the hardness of the inside is satisfied. The sponge elastic layer is
2. The sponge roll for an electrophotographic apparatus according to claim 1, wherein the inner part is harder than the surface part by an impregnation component impregnated in the inner cell. The sponge elastic layer is
A water repellent component is attached to the cell inner wall surface of the surface portion, and the inner cell is impregnated with a water-based impregnation component, so that the interior is formed to be harder than the surface portion. The sponge roll for electrophotographic equipment according to claim 1 or 2.   2. The electrophotographic apparatus according to claim 1, wherein the sponge elastic layer has the surface portion formed more flexibly than the inside by modifying a material forming the surface portion. Sponge roll.   The sponge roll for an electrophotographic apparatus according to claim 4, wherein the modification is decomposition of a material forming the surface portion.

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