JPS6079362A - Developer for electrostatic charge image - Google Patents

Abstract

PURPOSE:To prevent the sticking of a toner surface of a photosensitive body by mixing the toner particles contg. a thermoplastic resin, colorants and polyvinylidene fluoride and polyvinylidene fluoride powder. CONSTITUTION:When a fixing system applied is a heat oven system or a heat roll system, a thermoplastic resin or a resin mixture having >40 deg.C glass transition point is used as a resin for fixing. The amount of the resin for fixing contained in a toner is >=35wt% of the total amount of the toner, and the amount of a pigment for color control and a dye is <10wt% of the total amount of the toner. The toner is composed of the resin, the colorants and polyvinylidene fluoride. Magnetic powder may be added to the toner to obtain a magnetic toner. The amount of the ferromagnetic body contained in the toner is 35-75wt% of the total amount of the toner. To the toner particles is added 0.02-5wt% polyvinylidene fluoride powder basing on the total amount of the toner particles, and they are mixed. The sticking of the resulting toner to a photosensitive body and the damage of the photosensitive body can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatic image developer used for developing an electrostatic image formed on the surface of an image carrier by a magnetic brush method.

An electrostatic charge image is formed on the surface of an image carrier such as zinc oxide, pyrene, an organic photoconductor, or magnetized cadmium coated with Mylar (trade name), and this electrostatic charge image is developed by a magnetic brush method to obtain a toner. An electrophotographic copying method in which an image is transferred onto a transfer sheet 1 and then fixed to obtain the final images is as follows:
well known.

In the above-mentioned magnetic brush method, a mixed powder of magnetic carrier such as iron powder, steel balls, ferrite particles, etc. and non-magnetic toner, which is insulating particles with colorant dispersed in resin, is often used as a developer. (For example, Special Publick Publication No. 53-150
No. 40, JP 1050-56946, JP 54-13
No. 4636.

1i1i156-11459, 1st issue, 56-11460, etc.). In the magnetic brush development method using this two-component developer, carrier and toner are mixed and stirred at a predetermined ratio, and both are frictionally charged to charge the toner to a predetermined polarity, so that only the toner adheres to the surface of the image carrier. Something,
It has the advantage of being easy to transfer because it uses an insulating toner.

As other magnetic developers, one-component magnetic toners containing resin and LA bamboo powder as main components are known (for example, JP-A-49-4532, JP-A-50-50042, and JP-A-57-1999). (Refer to each publication of No. 9754).

However, these magnetic developers are
When using this method, there is a problem that toner particles adhere to the surface of the photoreceptor or the surface of the photoreceptor is damaged by the toner particles. For example, in a two-component developer, the toner particles are made of a thermoplastic resin with a fine particle size (5 to 30 μm) and a relatively low temperature (90 to 110°C) from the viewpoint of fixing properties. Easily adheres to surfaces. Furthermore, if the 1-toner remaining on the surface of the photoreceptor after transfer is cleaned by internal means of the Bll, such as a blade, the toner is easily crushed and pushed into the surface of the photoreceptor, damaging it. Alternatively, in the case of magnetic toner, since the magnetic powder is exposed on the surface of the L-toner particles (for example, the EVA portion I1
(Refer to Japanese Patent No. 156-46596), there is a problem in that the surface of the photoreceptor has ridges.

It is an object of the present invention to overcome the drawbacks of the prior art and to provide a developer for electrostatic images that effectively prevents adhesion and damage to the surface of a photoreceptor.

The constitution of the present invention resides in an electrostatic image developer containing polyvinylidene fluoride powder mixed at least with a thermoplastic resin.

Ordinary toner particles contain resin, colorant, etc. as essential components, but as a result of study by the present inventors, the toner particles contain polyvinylidene fluoride inside them, and the toner particles contain polyvinylidene fluoride It has been discovered that adhesion of toner particles to the photoreceptor and damage to the photoreceptor can be effectively prevented by mixing with powder. This polyvinylidene fluoride is a type of fluororesin (CF2
= CI-12> Excellent mold releasability and strong heat resistance (melting point 160-180°C, heat distortion temperature 90°C),
It also has excellent mechanical properties (tensile strength 390-5
20k (1/CJI2.Bending rigidity 1.4~1.8X1
0''1 ((110n+2)), it is thought that such an effect can be exhibited.

The blending amount of polynylidene fluoride is preferably in the range of 0.02 to 5% by weight based on the size of the toner particles. This is 0
．． This is because if the amount is less than 0.2% by weight, there is no effect, and if it exceeds 5% by weight, the fixing performance will be impaired. In addition, more preferably, the blending amount of polyvinylidene fluoride is 0.1 to 2.
It is in the range of weight percentage. Specific examples of polyvinylidene fluoride include 461, 460, 450, 3 manufactured by Pennwald.
An example is 10W.

Furthermore, the polyvinylidene fluoride used for mixing is 0.
01-5% by weight, preferably 0.5-2% by weight
It is. Even if it is less than 0.01% by weight, it will not be contained in the toner!
It L/Dai also has an effect, but it is small. 5% by weight
If this is the case, more particles will be scattered inside the copying machine.

The fixing resin needs to be appropriately selected depending on the fixing method. When the fixing method is an oven method using heating or a heat roll method such as a heat roll, for example,
The following thermoplastic resins are used. styrenes,
Homopolymers obtained by polymerizing monomers such as vinyl esters, α-methylene aliphatic monocarboxylic acid esters, acrylonitrile, methacryl O21-lyl, acrylamide, vinyl ethers, vinyl ketones, N-vinyl compounds, Alternatively, a copolymer obtained by copolymerizing a combination of two or more of these monomers, or a mixture thereof may be used. In addition, O-gin modified phenol'polmarine resin,
Hisphenol type epoxy resin.

Oil-modified epoxy resin, polyurethane resin, l! Non-vinyl resins such as non-vinyl thermoplastic resins such as Lerose resin, polyether resin, and polyester resin, or mixtures of these and vinyl resins as described above may also be used.

In particular, when fixing the developed image by heating in an oven, bisphenol-type epoxy resins and bisphenol-type polyester resins are preferable, and when fixing using a hot roll, resins containing styrene resin as the main component are preferred. , or polyether resin is desirable. The higher the styrene content of styrenic resin, the more the release rate against hot rolls (
4+ improves. Further, in order to further improve the mold releasability against hot rolls, fatty acid metal salts, low molecular weight polyethylene, polypropylene, higher fatty acids having 28 or more carbon atoms, and natural or synthetic paraffins are used.

It is effective to add thermoplastic rubber or the like.

These resins can be arbitrarily selected and mixed as desired; however, in order not to reduce the fluidity when used, it is necessary to use a resin whose glass transition point exceeds 40°C or a resin mixture. is used effectively. The color of the fixing resin contained in the toner is the proportion excluding ferromagnetic fine particles, color-adjusting pigments, dyes, and charge control agents, but it should be at least 35% by weight of the total amount of the toner in order not to reduce the fixing properties of the toner. need to be added.

As the color-adjusting pigments and dyes, any of the various pigments used in general dry developers can be used.

However, the amount of addition to the total m of toner needs to be within a range that does not reduce the electrical properties of the toner.

In the present invention, the amount of these additions is 1 to the total amount of toner.
Less than 0% by weight is suitable. Pigments and dyes that can be used include, for example, nigrosine dye fit, aniline blue, carfoil blue, DuPont oil red, quinoline yellow, methylene blue chloride, lid [1 cyanine blue, malachite green A chloride, lamp black, rose bengal and the like. A mixture of is used. If the ferromagnetic fine particles themselves are colored and there is no need to add these color modifiers, there is no need to add them to the toner.

In addition, when carbon black is used, since carbon black is a conductive particle, it does not reduce the electrical insulation properties of the toner. It is necessary to add within this range.

The above-mentioned pigments and dyes are used in combination with ferromagnetic fine particles and fixing resin to control frictional charging with the sleeve surface of the magnetic roll for toner development and the surface of the recording medium. It can be selected and used. However, in order to control the charge of the toner, conventionally known dyes or pigments can be added as charge control agents. For example, nigrosine dye, which has positive triboelectric properties,
Other examples include nigrosine dyes modified with higher fatty acids and metal-containing (Cr) azo dyes having negative triboelectric charging properties.

I-No- according to the present invention is composed of resin 1 colorant and polyvinylidene fluoride, and may be mixed with a magnetic carrier to form a two-component developer, or may be made into a two-component developer by containing magnetic powder in toner particles. It can be coated with other magnetic toners. In this case, the magnetic powder includes substances that are extremely strongly magnetized in the direction of °C by a magnetic field, such as iron, cobalt, nickel, and other elements that exhibit ferromagnetism, such as ferrite and magnetite. Alloys or compounds, and various alloys that exhibit ferromagnetism by subjecting them to some kind of treatment such as heat treatment, can also be effectively used.

Since these ferromagnetic substances are contained in the toner, it is desirable that the average particle size is 0.1 to 3 μm f1 degree, and the darkness contained in the toner is 35% of the total weight of the toner.
It is desirable to set it to 75 weight ω%. If it is less than 35% by weight, the magnetic force of the toner will decrease and the toner will be less than 1111% by weight than the sleeve.
This will cause the image to become distorted and the fluidity of the toner will also decrease. If it exceeds 75% by weight, the fixing performance will deteriorate.

The developer according to the present invention can be prepared using the above-mentioned compositions by a known manufacturing method, such as a pulverization method or an air drying method.

Next, examples of the present invention will be described.

Example 1 Epoxy resin (Shell Chemical Co., Ltd. 1 pico-1 to 1004) 4
0i1i1i part, FeaO4 (El manufactured by Toda Kogyo) 15
00) 69 heavy space and 0.5 parts by weight of polyvinylidene fluoride (461 manufactured by Pennwald) were mixed in a heating kneader at 160'C, then cooled and solidified, and this cold fJI
Roughly crush the solidified material with a ball mill, then jet 1~
It was finely pulverized in a mill to obtain particles with an average particle size of 20 μm. After classifying these particles, they were mixed with the above polyvinylidene fluoride 0.5 weight ω portion to obtain a τ particle size of 5 to 25, czm, and resistance of 5×10I4Ω.
・cm magnetic toner was obtained. Using the obtained magnetic toner, a transferred image was obtained with copying machine 1 (CP1015) using an Sc drum, and it was fixed in an oven fixing machine heated to 150°C for a 50,000-sheet copy test. No definitive scratches or 1-ner adhesion was observed.

Comparative Example 1 A magnetic toner was prepared in the same manner as in Example 1 except that polyvinylidene fluoride was not added, and when copies were made, scratches on the photoconductor were observed after about 20,000 copies were made. Stronger toner sticking was observed in one part.

Example 2 1 part by weight of polyvinylidene fluoride (manufactured by Pennwald Co., Ltd. 450), styrene-butadiene copolymer Kugutsutoi 7-
37 parts by weight of Briolide S-5B manufactured by Sanyo Chemical Co., Ltd., 3 parts by weight of low molecular weight polyethylene (151P manufactured by Sanyo Chemical Co., Ltd.), Fe
2O2 (manufactured by Toda Kogyo Co., Ltd. E1) T500) by weight was mixed, and the polydinylidene fluoride was mixed with the classified toner particles to prepare a magnetic toner in the same manner as in Example 1.

Thereafter, a 50,000 copy test was conducted using a copying machine using a Se drum, and it was confirmed that the surface of the Se drum was good.

Comparative Example 2 A copy test 4 was conducted using a magnetic toner with no magnetic toner, and strong toner adhesion was observed on the photoreceptor after printing 4,000 copies.
It appeared as a black dot on the white part of the image.

Example 3 1 part of polyvinylidene fluoride 2ffiff was first added to styrene acrylic resin (styrene-n-butyl methacrylate, number average molecular ff 120000, weight average molecule m 22
．． 0000) 78 parts by weight, 10 parts by weight of low molecular weight polypropylene (Viscol 550P manufactured by Sanyo Chemical Co., Ltd.), and 10 parts by weight of carbon black (#30 manufactured by Mitsubishi Chemical Co., Ltd.),
A toner was prepared in the same manner as in Example 1 by mixing polyvinylidene fluoride with the classified toner particles. These 1 to 5 heavy lifting parts are connected to an iron powder carrier (EFV2 made by Nippon Iron Powder).
00/300) 95 parts O to adjust the developer, and use a commercially available copier (DC131 manufactured by Mita) to evaluate the image quality (+lI).
When Example 1 was conducted, good results were obtained as in Example 1.

Comparative Example 3 A developer was prepared under the same conditions as in Example 3, except that polyvinylidene fluoride was not added, and image evaluation was performed. As in Comparative Example 1, unsatisfactory results were obtained.

As described above, the present invention has the advantage that polyvinylidene fluoride powder is mixed with L-ner particles containing at least a non-plastic resin, a colorant, and polyvinylidene fluoride, thereby preventing adhesion to and damage to the surface of a photoreceptor. This invention can be expected to provide a developer for electrostatic images that can effectively prevent this, and can be said to be an invention with excellent practical effects.

1″I night applicant 1] Rikineki Co., Ltd.

Claims (2)

[Claims] (1) A developer for electrostatic images, characterized in that polyvinylidene fluoride powder is mixed with toner particles containing at least a thermoplastic resin and polyvinylidene fluoride. (2) The developer for electrostatic images according to claim 1, which contains magnetic powder as at least a part of the colorant.