JPH06295137A - Fixing method - Google Patents

Abstract

PURPOSE:To obtain a high-resolution picture fulfilling transferability and fixability by improving the offset of a toner on a fixing roller without using a release agent to suppress the offset of the toner in the fixing process. CONSTITUTION:A picture formed on a transfer paper is fixed by this fixing method., In this case, the picture formed on the transfer paper is fixed with a roller wetted with a liq. consisting of a toner having 0.1-2mum volume average grain diameter, with the ratio of the volume average diameter Dv to the number average grain diameter Dp controlled to 1 to 1.2 and having <=200 centistoke viscosity (120 deg.C) on the fixing roller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner and a fixing process for developing an electrostatic latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method or the like.

[0002]

2. Description of the Related Art Generally, in electrophotography, electrostatic recording, etc., development is performed in order to develop an electrostatic latent image formed on a latent image carrier made of a photoconductive photoconductor or a dielectric. After the toner image is thinned by a blade etc. on a toner supply roller such as a sleeve and properly charged and finely powdered, the toner image is transferred to a transfer material such as paper, if necessary, and then heated. It is fixed by pressure, solvent vapor, etc. to obtain a copy.

The toner applied to these developing methods generally fixes the toner image formed on the transfer paper by heating pressure, and uses thermal energy to improve the offset property to the roller at the fixing portion. In addition, an oil applicator is provided in the fixing device, or a release agent is used in the toner. However, if an oil applicator is installed in the fixing device, it will be a factor of cost increase, or trouble or maintenance will be required, which will increase the burden on the user and is not preferable. Further, when a large amount of a release agent is used in the toner, the spent phenomenon of the toner on the photoconductor or the carrier is observed, and the image is disturbed and the density is lowered due to deterioration of charging, which is also not preferable. Further, since heat energy is used to fix the toner to the transfer material, the power consumption becomes large or the time until the first copy is required, so that it is not a preferable fixing device for the user.

The phenomenon as described above is observed in the kneading type toner and the polymerization type toner. In the case of the polymerization type toner, if the releasing material is present on the surface of the toner, the transfer rate is deteriorated, and it is obtained. The resulting image will be very faint. In addition, the poor transfer rate also increases the amount of cleaning toner and causes cleaning failure. Therefore, it is necessary to reduce the amount of the release material or to satisfy the releasability with respect to the fixing roller and the transferability / fixability with respect to the transfer material without the release material.

As described above, the toner prescription is used from the viewpoint of the fixing device in order to improve the fixing characteristics. Regarding the toner formulation, attempts have been made to improve the fixing characteristics by adding a release material or controlling the molecular weight distribution, but at present the sufficient characteristics have not been obtained.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to improve the offset of toner to a fixing roller without using a release agent in order to suppress the offset of toner in the fixing process, and to improve transferability and fixability. To be fully satisfied. The purpose is to obtain a higher resolution image.

As a result of earnest research for solving the above-mentioned object, (1) in a method of fixing an image formed on a transfer paper, the image formed on the transfer paper has a volume average particle diameter of 0.1 to 2 μm. It is made of toner, and the ratio of the volume average particle diameter (D _v ) to the number average particle diameter (D _p ) is D _v / D _p = 1 to
The object can be achieved by using the fixing method of fixing the image on the transfer paper with a roller which is 1.2 and which is wet with a liquid having a viscosity of 200 centistokes (120 ° C.) or less on the fixing roller. It was

The toner transferred onto the transfer material is not fixed yet, and is easily detached from the transfer material by touching it with a finger. In the present invention, the fixing roller is wetted with the liquid and compressed between the fixing roller and the backup roller,
When the liquid wets the transfer material as well as the toner on the transfer material, the affinity between the toner and the transfer material is increased, and the toner can penetrate into the gap between the transfer materials. At this time, if the particle diameter of the toner becomes 2 μm or more, when the transfer material is paper, for example, it remains on the fiber and cannot be completely fixed. If the toner is preferably 1 μm or less, the toner will not only penetrate into the space between the fibers but also into the space between the fibers, and the fixing of the toner will be almost complete. If the particle size of the toner is smaller than 0.1 μm, it becomes difficult to satisfy the entire electrophotographic process, which is not preferable. Since the liquid used at this time increases the affinity between the transfer material and the toner, it is suitable that the viscosity is low to some extent. When the viscosity of the liquid at 150 ° C. exceeds 200 centistokes, even if the liquid has a high affinity with the transfer material or the toner, the liquid cannot be wetted to the transfer material enough to fix the toner on the transfer material. That is, the lower the viscosity, the better. However, there is a problem if it is too low, and it is preferable that the viscosity is such that the liquid does not fall freely from the fixing roller. The higher the affinity with the transfer material or the toner, the better the quality, but this is not a serious problem in the present invention.

At this time, heat energy may be used together with wetting and pressure of the fixing roller to assist the fixing of the toner. However, if the temperature becomes too high, hot offset will be generated in the fixing roller, so that it is necessary to set an appropriate temperature. As a method for applying heat energy, it may be applied from a backup roller or may be separated into a wet roller and a heat donating roller with two fixing parts. The toner is polymerized by kneading and crushing type toner (suspension polymerization
A dispersion polymerization or emulsion polymerization type toner may be used.

Liquids used in the fixing roller of the present invention include hexanol [boiling point 155 ° C., 60 centistokes (120 ° C.)], heptanol [boiling point 176 ° C., 7].
0 centistokes (120 ° C)], octanol [boiling point 194.5 ° C, 80 centistokes (120 ° C)
)), Isooctanol [105 centistokes (120 ° C)], and aliphatic hydrocarbons having 20 or less carbon atoms, but are not limited thereto.

Monomers forming the binder resin used in the present invention include styrene, o-methylstyrene,
m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-
Styrenes such as nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, and 3,4-dichlorostyrene; ethylene, propylene, butylene, Ethylenically unsaturated monoolefins such as isobutylene, vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromine, and vinyl fluoride; vinyl esters such as vinyl acetate, vinyl propionate, and vinyl acetate, methyl acrylate, acrylic Α such as ethyl acetate, -n-butyl acrylate, methyl methacrylate, ethyl methacrylate
-Methylene aliphatic monocarboxylic acid esters, vinyl ethers such as vinyl methyl ether, vinyl ketones such as vinyl methyl ketone, N-vinyl such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole and N-vinylpyrrolidone A compound etc. can be illustrated. These monomers can be used alone or in combination of two or more kinds.

Further, as the monomer for forming the polycondensation type resin, ethylene glycol, triethylene glycol, 1,2-propylene glycol, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, poly Polyhydric alcohols such as oxypropyleneized bisphenol A, polyamines such as ethylenediamine, tetramethylenediaminepiperazine, and maleic acid, fumaric acid, mesaconic acid, citraconic acid, adipic acid, malonic acid, or their acid anhydrides or lower alcohols. Examples thereof include esters with and the like. Further, the resin monomer shown here is not limited to the above.

Additives such as colorants and charge control agents can be used in the toner of the present invention, and examples thereof include metal chelate dyes such as carbon black, oil black, nigrosine dyes and metal-containing dyes, and aniline dyes. , Chalco oil blue, chrome yellow, ultramarine blue, methylene blue chloride, phthalocyanine blue, rose bengal, and other dyes or pigments.

Further, a fluidizing agent can be used in the toner of the present invention, for example, SiO ₂ or TiO ₂ whose surface is made hydrophobic.
And the like, inorganic fine particles such as SiC, metal soap such as zinc stearate, and the like can be used.

[0015]

EXAMPLES Examples of the present invention will be specifically described below, but the present invention is not limited thereto. Example 1 Base particles were produced by the dispersion polymerization method as described below. A 500 ml three-necked flask equipped with a stirring blade and a condenser was charged with 300 g of methanol and 100 g of ion-exchanged water, and the polymer dispersant Gantret (average molecular weight 40,000) was added.
6.4 g was added little by little with stirring to completely dissolve it. Further, the following composition was added and completely dissolved.

Styrene 70.0 g Methyl acrylate 30.0 g 2,2′-Azobisisobutyronitrile 0.2 g Dodecyl mercaptan 0.3 g While stirring these, the inside of the flask was purged with nitrogen gas and left for 1 hour. Polymerization was initiated while stirring at a stirring speed of 100 rpm in a constant temperature water bath of 60 ° C. ± 0.1 ° C. After 15 minutes of heating, the liquid started to become cloudy, and it remained a cloudy and stable dispersion even after 20 hours of polymerization. As a result of partially sampling and measuring by gas chromatography by the internal standard method, it was confirmed that the polymerization rate was 78%. The obtained dispersion is cooled and centrifuged at 1000
Upon centrifugation at rpm, the polymer particles were completely settled and the upper liquid was transparent. The supernatant was removed, 250 g of methanol and 150 g of ion-exchanged water were added, and the mixture was stirred and washed for 1 hour. The procedure of centrifuging and washing with methanol was repeatedly filtered. The material separated by filtration was dried under reduced pressure at 50 ° C. for 24 hours to obtain styrene / methyl acrylate particles as white powder with a yield of 95%. The obtained particles had a volume average particle diameter Dv = 0.75 μm [hereinafter, the polymer particles are referred to as (A)].

Next, 1.0 g of Oil Black 803 [Orient Kagaku Co., Ltd.] was dissolved in 200 g of methanol by heating, cooled, and filtered with a 0.5 μm filter to prepare a dye solution. Next, 24 g of polymer particles (A) were added to and dispersed in the filtrate, and heated and stirred at 50 ° C. for 1 hour. Thereafter, the dyed resin particle dispersion liquid (B) was cooled to room temperature and filtered to obtain colored resin fine particles. This was vacuum dried at room temperature for 24 hours, and 1.5 parts of silica was added and mixed to obtain a toner.

Next, the fixing portion of the Ricoh copy machine IMAGIO 420 was improved, and isopentanol (50 centistokes: 50 cm) was added to the oil applicator to which the fixing roller was attached.
(120 ° C) is put in by a pump, and isopentanol is applied to the roller with a felt, and 100 parts of the ferrite carrier is mixed with 3 parts of toner using the toner prepared above to form an image, and a fixed image is formed. Output. The image obtained was one that was completely fixed at high resolution. Also, no hot offset was observed.

Example 2 The same procedure as in Example 1 was conducted except that the toner obtained in Example 1 was mixed with a carrier as in Example 1 and hexanol (40 centistokes: 120 ° C.) was used. I made an image. The image obtained was one that was completely fixed at high resolution.

Example 3 A toner was prepared in the same manner as in Example 1, except that ion-exchanged water was not used during the polymerization of particles. The volume average particle diameter of the obtained toner is 4.8 μm.
It was m. Images were similarly printed using the copying machine used in Example 1. Although the obtained image had high resolution, a hot offset phenomenon was observed in the fixed image.

Comparative Example 1 The same toner as in Example 1 was used, and an alkyl-modified silicone oil having a kinematic viscosity of 500 centistokes was used in the same fixing portion as in Example 1 to form an image. 100
The image was defectively fixed after the output of 0 images.

Comparative Example 2 Images were printed by replacing the alkyl-modified silicone oil used in Comparative Example 1 with an epoxy-modified silicone oil having a kinematic viscosity of 700 centistokes. After the output of 1,000 sheets of images, the images were incompletely fixed.

Comparative Example 3 The alkyl-modified silicone oil used in Comparative Example 1
Images were displayed by changing to silicone oil of 00 centistokes. After the output of 1,000 sheets of images, the images were incompletely fixed.

[0024]

As described above, according to the present invention, the transferability and fixing property of the toner onto the transfer material can be improved.

Claims (1)

[Claims] 1. A method for fixing an image formed on a transfer paper, wherein the image formed on the transfer paper is made of toner having a volume average particle diameter of 0.1 to 2 μm, and the volume average particle diameter (D
The ratio of _v ) to the number average particle size (D _p ) is D _v / D _p = 1 to 1.2.
And the roller on which the toner is fixed is wet with a liquid having a viscosity of 200 centistokes (120 ° C.) or less,
A fixing method characterized by fixing an image on a transfer paper.