JP3273621B2 - Roller and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various rollers in printers for electrophotography, electrostatic recording, and the like, and more particularly to a roller used in contact with a photosensitive drum and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic process of supplying toner prepared in a toner cartridge to a photosensitive member having an electrostatic latent image formed thereon, and transferring and fixing the toner on paper is generally performed by charging, exposing, developing, Transfer, fixing, static elimination,
It consists of each mechanism of cleaning, and various rollers are used in each mechanism. However, polyurethane foam has come to be widely used as a roller material because of its flexibility and low compression set.

[0003]

However, in particular, the rollers used in each of the charging, developing, transferring, and cleaning mechanisms are often used in contact with a photoreceptor, and a roller made of polyurethane foam is used in such an application. However, there is a problem that the copy is unclear when using the method. The present invention, as described above, as a result of investigating the cause of a copying problem when using a polyurethane foam roller, as a result, migrating substances such as unreacted monomers or oligomers and other non-reactive additives of the polyurethane foam forming the roller body. As a result of finding out that this is caused by migration to and contamination of the photoreceptor drum, various coating materials were tested to prevent the migration of these contaminants to the photoreceptor. An object of the present invention is to provide a roller free from such defects by treating the surface with a liquid dispersed in water and a method for producing the same.

[0004]

In order to achieve the above-mentioned object, the roller of the present invention is applied to the surface of a roll-shaped inner layer.
It is obtained by forming the outer <br/> layer comprising a polyolefin resin containing no conductivity-imparting material, this roller, the process a roll of inner surface of the self-emulsifying the polyolefin resin in a liquid dispersed in water And a step of drying to form an outer layer of a polyolefin resin on the surface of the inner layer.

[0005]

The roller of the present invention does not contaminate the photosensitive drum even when it comes into contact with the photosensitive drum. Further, according to the manufacturing method of the present invention, a uniform outer layer can be formed, the manufacturing operation is easy, and the environment is not adversely affected.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polyurethane foam used as the inner layer 1 of the roller of the present invention comprises a compound containing two or more active hydrogens (polyhydroxyl compound), a compound having two or more isocyanate groups (polyisocyanate compound) and a catalyst. Polyurethane foam obtained by foaming and curing by stirring and mixing with additives such as foaming agents, foaming agents and foam stabilizers. Polyhydroxyl compounds include polyols used in general production of flexible polyurethane foams and urethane elastomers. Hydroxyl-containing polyether polyols, polyester polyols,
And a polyether polyester polyol which is a copolymer of both, and a general polyol such as a so-called polymer polyol obtained by polymerizing an ethylenically unsaturated monomer in the polyol can be used. Further, as the polyisocyanate compound, polyisocyanates which are used for producing general flexible polyurethane foams and urethane elastomers can also be used. That is, tolylene diisocyanate (TDI), crude TDI, 4,4-diphenylmethane diisocyanate (MDI), crude MD
I, aliphatic polyisocyanates having 2 to 18 carbon atoms, alicyclic polyisocyanates having 4 to 15 carbon atoms, and mixtures and modified products of these polyisocyanates, for example, prepolymers obtained by partially reacting with polyols, etc. Used. Further, as for the catalyst, the foaming agent and the foam stabilizer, those used in general urethane foam production can be used as they are, and there is no particular limitation. Or using general H ₂ O as a blowing agent with respect to foaming method, and a method for foaming and curing was stirred discharge using a volatile solvent as a blowing agent, H ₂
Without using O or an organic solvent, the polyhydroxy component and the polyisocyanate component are foamed in advance by mechanical stirring with a catalyst and a foam stabilizer, discharged, and cured by heating. The so-called mechanical floss method is also useful as a roller foam material. Various fillers, conductivity-imparting substances and the like can be added as needed.

As a means for coating the outer layer 2 formed on the surface of the inner layer 1 of the polyurethane foam, there is a method of dissolving a thermoplastic resin having no impurities in a solvent, and applying the solution. It is not preferable because the cost is increased due to measures and the polyurethane foam swells depending on the solvent and there is a problem in dimensional stability.A water-based coating material is preferable, but a general aqueous resin dispersion is used to disperse the resin. Various additives such as surfactants are contained, and these additives are not preferable because they cause contamination. Further, as the resin, a resin having a softening point of 50 ° C. or less after drying, or a hydrophilic resin is not preferable because it has a problem of sticking and adhesion to a photosensitive drum when used under high temperature and high humidity conditions. Softening point 50 ° C
A water dispersion of the above-mentioned self-emulsifiable polyolefin resin is preferred, and an auxiliary additive for emulsification is preferably volatilized and removed during heating and drying.

Production Example Polyether polyol having a molecular weight of 5,000 by adding propylene oxide and ethylene oxide to glycerin (Exenol 828 from Asahi Glass Co., Ltd.) (OH value: 33)
100 parts urethane-modified MDI (Sumijur PF from Sumitomo Bayer Urethane Co., Ltd.) (NCO% = 23%)
25.0 parts 1,4-butanediol 2.5 parts Silicone surfactant (L-520 manufactured by Nippon Yunika)
1.5 parts Nickel acetylacetonate 0.5 parts Dibutyltin diurarate 0.01 parts Natural graphite having an average particle size of 2.5 μm and a fixed carbon content of 99% (Nippon Graphite Co., Ltd.) High purity graphite AOP)
... 50 parts (28% by weight based on the total resin amount) These were put in a 1-liter plastic container, and stirred for 2 minutes with a household whisk to obtain a foam having fine uniform cells. This foam has a length of 2
A 8 mm iron shaft 3 was poured into a mold having a length of 00 mm, a width of 30 mm and a depth of 30 mm in the center, and was cured by heating at 140 ° C. for 7 minutes to obtain a polyurethane foam for a roller. Next, this is polished, the shaft length is 220 mm,
An uncoated roller having an inner layer 1 having a length of 200 mm and a diameter of 20 mm as shown in FIG. 100% after impregnation (adhesion amount: 3 g / piece)
The sample was dried in an oven at 20 ° C. for 20 minutes to obtain a surface-coated sample (the outer layer 2 was formed).

The roller was pressed against the photosensitive member of a commercially available printer, and after a lapse of 10 days at 50 ° C., the roller was removed and copying was evaluated. The image was good and there was no problem of contamination. The uncovered product was a black copy on the entire surface, and it was found that the pressed portion was white and the photoconductor was contaminated.

[0010] As the inner layer 1, a roll-shaped rubber having appropriate flexibility and various plastic materials can be used in addition to the polyurethane foam.

[0011]

As described above, according to the roller of the present invention, contamination of the photosensitive drum can be prevented. Particularly, when the inner layer is made of polyurethane foam, the roller has flexibility, low compression set, and low copy performance. Deterioration can also be prevented. Further, according to the production method of the present invention, since a liquid in which a self-emulsifiable polyolefin resin is dispersed in water is used, coating can be performed by a simple processing operation without adversely affecting the environment.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a roller.

FIG. 2 is a perspective view before surface coating.

[Explanation of symbols]

 1 shaft 2 inner layer 3 outer layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-266109 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 7/04 F16C 13/00

Claims (5)

(57) [Claims] 1. A material for imparting conductivity to a surface of a roll-shaped inner layer.
A roller forming an outer layer comprising a polyolefin resin containing no. 2. The roller according to claim 1, wherein the inner layer is formed of a polyurethane foam. 3. The outer layer is formed of a self-emulsifying polyolefin resin having a softening point of 50 ° C. or higher.
Or the roller according to 2. 4. A roller comprising: a step of treating the surface of a roll-shaped inner layer with a liquid in which a self-emulsifiable polyolefin resin is dispersed in water; and a step of drying to form an outer layer of a polyolefin resin on the surface of the inner layer. Manufacturing method. 5. The method according to claim 4, wherein a polyurethane foam is used as the inner layer.