JPS6017109B2 - Heating roller fixing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of fixing a toner image made of a toner for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, etc. onto a fixing sheet using a heated roller.

Methods for developing electrostatic images are broadly divided into liquid development methods that use a developer in which various pigments and dyes are finely dispersed in an insulating organic liquid, cascade methods, bristle brush methods, magnetic brush methods, and impression methods. There are so-called dry developing methods, such as the powder cloud method, which use a fine powder developer called toner in which a coloring agent such as carbon black is dispersed in a natural or synthetic resin, and the present invention is applicable to the latter dry developing method. The present invention relates to a method for fixing a toner image made of toner on a sheet to be fixed.

Generally, toner deteriorates after being developed several thousand times as it undergoes mechanical abrasion due to shear and impact forces during mechanical operations in a developing device. In order to prevent such toner deterioration, it is possible to use a strong resin with a large molecular weight that can withstand mechanical abrasion as a toner component, but these resins generally have a high melting point and are finely powdered. This is difficult when producing toner. For this reason, toner containing such a high melting point resin is used on the fixing sheet. For example, if a non-contact heating device using an electric furnace is used as a fixing device, sufficient fixing cannot be performed and it is necessary to operate at a higher temperature because this fixing device has low thermal efficiency. Therefore, the power consumed for fixing increases and the sheet to be fixed becomes discolored or burnt, and there is also a limit to the fixing speed. On the other hand, when a deposition heating device using a heating roller is used as a fixing device, this device makes pressure contact between the heating roller surface and the toner image surface of the sheet to be fixed, so the thermal efficiency is extremely high, compared to a non-contact heating device. Although it has the advantage of being able to fix quickly with less thermal energy, when the surface of the heating roller and the toner image surface come into pressure contact, the toner tends to adhere to the surface of the heating roller and cause the so-called offset phenomenon. To prevent this, the surface of the heating roller must be made of a material that has excellent adjacency to the toner, such as a fluorine-based resin, and the surface of the heating roller must be supplied with a release agent such as silicone oil by means of coating or other means. There is a need to. In addition, since Hikata-based resins are generally non-conductors when it comes to heat, in order to fix toners containing resins with high melting points at a higher speed, it is necessary to keep the heated roller temperature high. It is necessary to increase the supply of thermal energy. However, fluorine-based resins deteriorate rapidly and have limited durability when used continuously at high temperatures and under load. For example, Teflon (manufactured by DuPont), a typical fluorine-based resin, 20000B to 2
It must be used at temperatures below 3 degrees Celsius. There are also difficulties in using silicone oil at high temperatures, and the lubricating materials for the bearings of heating rollers and pressure-bonding loafs are also subject to heat resistance limitations. Furthermore, in order to maintain the temperature of the heating roller at a high temperature, a large amount of electric power is required, and a power distribution from a special power source is required. On the other hand, if a resin with a relatively small molecular weight is used as a toner component, the toner image can be fused to the fixing sheet at a relatively low temperature. A film tends to form on the surface of the developer carrier, degrading the image obtained and shortening the life of the photoconductor and developer carrier.

A further drawback is that they tend to cake or agglomerate during storage or mechanical operation. The purpose of the present invention is to
Can be fused onto the fixing sheet at a relatively low temperature, and when fixing using a heated roller fixing device, it fixes at high speed without causing an offset phenomenon without supplying a template agent to the heated roller surface. It is an object of the present invention to provide a method for fixing a toner image for electrostatic charge development, which can perform the following steps.

The present inventors have developed a method of heating a fixing sheet carrying a toner image made of an electrostatic charge developing toner containing a colorant, a styrene resin, and a low molecular weight propylene polymer without supplying a template agent to the surface of a heating roller. The above object has been achieved by a heated roller fixing method characterized in that the toner group is fixed on a fixing sheet by passing through and in contact with a roller. By using the method for fixing a toner image made of the electrostatic charge developing toner according to the present invention, it is possible to fix the toner image at a relatively low temperature using a contact heating device, particularly preferably a heated roller fixing device. , 4. It is possible to reach the enemy more quickly with less power consumption, and since it is possible to use a material with a low heat resistance limit as the heating roller material, its durability can be significantly improved, and this makes it possible to improve the performance of ultra-high speed copying machines. This has the advantage that design can be simplified.

．． Any suitable pigment or dye may be used as a colorant in the toner used in the present invention.

For example, carbon black, nigrosine dye, aniline flue, luco oil blue, chrome yellow, ultramarine flu, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine flu, malachite green oxalate, and Rumph. Black, rose bengal and mixtures thereof are used and need to be included in the toner in sufficient amounts to color the toner so that it can be developed to form a visible image. In the toner used in the present invention, a styrene resin is used as a resin component.

The styrene resin may be a homopolymer of stainless steel, or a copolymer of styrene and other vinyl monomers.
But that's fine. Monomers for forming these copolymers include p-chlorostyrene, vinylnaphthalene, ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, isobutylene, such as vinyl chloride, vinyl bromide, vinyl fluoride, acetic acid. Vinyl, vinyl esters such as vinyl propionate, vinyl benzoate, vinyl butyrate, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate,
Dodecyl acrylate, n-octyl acrylate, 2-chloroethyl acrylate-fenyl acrylate, Q-methyl chloroacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, etc. Esters of carboxylic acids, acrylonitrile, methacrylonitrile, acrylamide, pinyl ethers such as pinyl methyl ether, pinylethyl ether, vinyl isobutyl ether, such as vinyl methyl ketone, vinyl hexyl ketone, methyl isoprobenyl ketone vinyl ketones such as N
Examples include N-vinyl compounds such as -vinylpyrrole, N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidene, and one or more of these can be copolymerized with a styrene monomer. Suitable styrenic resins have a weight average molecular weight of about 3000 or more and preferably have a styrene component content of at least about 25% by weight based on the total weight of the styrenic resin. Thermoplastic resin systems mixed with other resins can also be used as the resin component of the toner according to the present invention.

Other resins that can be mixed with styrenic resins include:
Pinylnaphthalene, such as vinyl chloride, pinyl bromide,
Vinyl esters such as vinyl fluoride, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isoptyl acrylate, dodecyl acrylate, n-octyl acrylate , 2-chloroethyl acrylate, phenyl acrylate/Q-methyl chloroacrylate, methyl methacrylate, ethyl methacrylate,
Esters of Q-methylene aliphatic monocarboxylic acids such as butyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, vinyl ethers such as vinyl methyl ether, vinyl isobutyl ether, pinylethyl ether, e.g. vinyl Monomers such as vinyl ketoso compounds such as methyl ketone, pinylhexyl ketone, and methyl isoprobenyl ketone, and N-vinyl compounds such as N-vinylpyrrole, N-vinylcal/azole, N-vinylindole, and N-vinylpyrrolidene. A homopolymer obtained by polymerizing a monomer, a copolymer obtained by copolymerizing a combination of two or more of these monomers, or a non-vinyl resin such as a rosin-modified phenol-formalin resin, an oil-modified epoxy resin, a polyurethane resin, a cellulose resin, or a polyether resin. There are thermoplastic resins. . When these resins are used in mixtures with styrenic resins, both should be mixed in an amount such that at least about 25% by weight of the styrene component is present, based on the total amount of the resulting resin. Preferably, they are mixed. This is because the resistance to mechanical abrasion is increased and the patternability to heated rollers is excellent. The toner used in the present invention contains the following compounds.

The following compounds play a role in preventing the toner from adhering to the surface of the heated loaf and causing an offset phenomenon, and are generally preferably contained in an amount of 1 to 25 parts by weight per 100 parts by weight of the resin component of the toner. The above compound is a low molecular weight propylene polymer, and is a propylene polymer containing only propylene as a monomer component or a copolymer with other olefins, or a propylene polymer containing a monomer other than olefin as a monomer component. It is a propylene copolymer with a relatively low molecular weight.

Examples of other olefin monomer components include ethylene, butene-1, bentene-1, hexene-1, heptene-1, octene-1, nonene-1, decene-1, etc.
are homologues with different positions of unsaturated bonds or those in which an alkyl group is introduced as a branched chain, such as 3-methyl-1-butene, 3-methyl-2-bentene, 3-poly-5-methyl-2-hexene, etc. All olefins such as olefins are included. In addition, monomers other than olefin as monomer components that form a copolymer with propylene include, for example, vinyl methyl ether,
Vinyl ethers such as vinyl n-butyl ether and vinyl phenyl ether, vinyl esters such as vinyl acetate and vinyl petitroot, such as vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, vinyl chloride, vinylidesochloride, tetrachloro Haloolefins such as ethylene, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, stearyl methacrylate, N,N-dimethylaminoethyl methacrylate, t- Acrylic acid esters or methacrylic acid esters such as butylaminoethyl methacrylate, acrylic type derivatives such as acrylonitrile, N,N-dimethylacrylamide, acrylic acid, methacrylic acid, maleic acid, fumaric acid,
Various organic acids such as itaconic acid, jetyl fumarate, and 3-pinene can be mentioned.The weight average molecular weight of these low molecular weight propylene polymers is generally 10.
000 or less is effective, especially about 3000 to 8
Those having a weight average molecular weight of 0.000 are effective in the present invention. Generally, those having a large molecular weight have low compatibility and dispersibility with styrenic resins, and are therefore not desirable for use in the present invention. Furthermore, the toner used in the present invention
may contain a plasticizer having a melting point of about 40 to 140°C.

This plasticizer plays the role of lowering the fusing temperature of the toner, and also plays the role of improving the dispersibility of various additives such as dyes and pigments in the toner. Additionally, toner film formation on the photoconductor surface and developer carrier surface can be prevented, and toner caking or agglomeration during storage and machine operation can be prevented. Such plasticizers include, for example, dicyclohexyl phthalate, which is an ester of o-phthalic acid or m-phthalic acid, diphenyl phthalate, dihydroabiethyl phthalate, diethoxyethyl phthalate, dimethyl isophthalate, and benzoic acid. triethylene glycol dibenzoate, which is an ester of triethylene glycol dibenzoate, bentaerythritol tetrabenzoate, sutucarose benzoate, glyceryl tribenzoate, tricyclohexyl citrate, which is an ester of citric acid, and p-toluenesulfone, which is an ester of citric acid. amide, N-ethyl-p-toluenesulfonamide, N-cyclohexyl-p-toluenesulfonamide, triphenyl phosphate which is a phosphate ester; other examples include chlorinated paraffin, chlorinated polyphenyl, polyethylene glycol, etc. The amount of these plasticizers that may be contained in the toner is 1 to 45 parts by weight per 10 parts by weight of the resin component of the toner.
parts by weight, preferably 2 to 2 parts by weight.

Further, various other toner additives can be added to the toner used in the present invention as necessary. The toner image formed on the fixing sheet using the toner used in the present invention shows no toner offset phenomenon even when a fixing roller that does not apply offset prevention liquid to the surface of the fixing roller is used. It is possible to efficiently perform good heating low-fu fixing at a relatively low temperature.

The surface of the fixing roller can be made of, for example, Teflon,
Items with smooth surfaces made of Fluon (manufactured by ICI), Kelu F (manufactured by 3M), or relatively hard silicone rubber such as KE-130 dish TV (manufactured by Shin-Etsu Chemical). In some cases, those having a metal surface are effectively used. Next, the present invention will be illustrated by examples, but the embodiments of the present invention are not limited thereto.

In the examples, the number of copies is expressed by weight unless otherwise specified. Example '1' A copolymer of about 9 parts styrene and about 1 part dimethylaminoethyl methacrylate with a softening point of 12,000.
10 parts of anchor, 5 parts of Diablack SH (manufactured by Mitsubishi Kasei Corporation, carbon black), and ethylene-propylene copolymer (copolymerization molar ratio 50:50, weight average molecular weight 40
00) and 15 parts of tricyclohexyl citrate were mixed and subjected to a ball mill for about 24 hours, passed through a fiber using a hot roll, cooled, and then ground to create a toner.Sample A
And so.

A toner was prepared as Sample B using the same procedure as described above, except that tricyclohexyl citrate was not added. Using these two types of toners, a fixing roller whose surface was made of Teflon was used to bring the toner images into contact with each other under pressure, thereby fixing the toner images.

As a result, the temperature at which the toner fuses to the fixing sheet is sample B.
When the toner of Sample A was used, it was 190C○, and when the toner of Sample A was used, it was 170oo. Furthermore, when the fixing operation was repeated and the occurrence of toner offset phenomenon was observed, it was found that no offset phenomenon occurred with any of the toners.

Claims (1)

[Claims] 1. A sheet to be fixed carrying a toner image made of an electrostatic charge developing toner containing a colorant, a styrene resin, and a low molecular weight propylene polymer is passed through a heating roller without supplying a release agent to the surface of the heating roller, A heated roller fixing method characterized by fixing the toner image on a fixing sheet by contacting the toner image.