JPS6169074A - Method for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To provide a satisfactory image which is stable with lapse of time by bringing the surface of an image forming member on which an electrostatic latent image is formed into contact with a specific developer to form a toner image on the member surface and transferring the toner image to a transfer material. CONSTITUTION:The electrostatic latent image is formed on the surface of the image forming member and the surface of such member is brought into contact with the developer contg. at least the toner particles contg. 0.05-20wt% a lubricating agent per weight of the toner in the toner and cerium oxide as the particles independent from the toner particles to form the toner image on the surface of the image forming member. The formed toner image is transferred to the transfer material and the developer remaining on the surface of the image forming member after the transfer is cleaned by a cleaning blade. The lubricating agent is exemplified by graphite, mica, talc, zinc white, PP, polytetrafluoroethylene, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called electrostatic image developing method in which an electrostatic latent image formed on the surface of an image forming member is developed as a toner image.

Photographic or printing methods are well known in the art that include the step of forming an electrical latent image (electrostatic latent image) and then visualizing it with toner. For example, as an electrophotographic method, U.S. Patent No. 2
．． Specification No. 297.691, Japanese Patent Publication No. 42-23.910
A number of methods are described in Japanese Patent Publication No. 43-24.748, etc., but in general, a photoconductive substance is used to form an electrical latent image on a photoreceptor by various means. Then, after developing the latent image using toner and transferring the powder image made of toner to a transfer material such as paper as necessary,
Copies are obtained by fixing by heat, pressure, solvent, etc. Examples of methods for visualizing electrical latent images using toner include the magnetic brush method described in U.S. Pat. No. 2,874,063, U.S. Pat.
The cascade development method described in No. 552 and the powder cloud method described in No. 2,221,776 are known. The toners used in these development methods include fine powders in which dyes and pigments are dispersed in binders.
Furthermore, Japanese Patent Publication No. 38-11.096, No. 40-10
, No. 866, No. 44-6.398, and the like, toners to which various third substances are added are also known. By the way, such developing methods can be roughly divided into wet methods and dry methods, and when a wet developer is used,
A highly insulating solvent such as Isopar H (trade name) as a carrier liquid effectively acts indirectly as a lubricant to reduce the coefficient of friction between the photoreceptor 1 and the cleaning blade, resulting in a smooth cleaning operation. are being implemented. However, in the dry developing method, an alternative lubrication method is required, and conventional methods of internal addition to the dry developing agent (...
...This is added to the toner) or externally added (...
...This is added independently from the toner), such as polytetrafluoroethylene, polyethylene, higher fatty acid metal salts, molybdenum disulfide, graphite, etc.
Attempts to improve the lubricity and cleaning properties on photoreceptors by adding agents are already well known. However, although the above-mentioned improvements are achieved by adding a lubricant to the developer, there remain disadvantages such as the observation of a film formation phenomenon that seems to be affected by the toner or lubricant on the photoconductor. In order to solve this problem, regulations on the type of lubricant and the amount added thereof have been considered, but at present no fully satisfactory solution has been obtained.

As a solution to refusing the request, a method is proposed in Japanese Patent Laid-Open No. 48-47.346.

This is a method in which an abrasive substance is further included in the toner to which a friction-reducing substance has been added. In this method, since both the friction-reducing substance and the abrasive substance are added internally to the toner, there is a disadvantage that the original effects of the two cancel each other out.
In reality, the ratio of the amounts of the two added must be strictly regulated, taking into consideration the expected effects.

In addition, since the toner contains both substances that are not essential components of the toner, it is possible to control the color density, fixability, tripo charge amount, etc. specific to the toner.

This requires extremely advanced technology.

In practice, there are severe restrictions.

Therefore, in the present invention, the conventional method as described above is used.

The main purpose is to eliminate problems found in the law.
The main objective is to provide a positively charged image developing method that improves the lubricity on the photoreceptor without impairing the characteristics of the toner, prevents film formation, and provides stable and good images over time. . Another object of the present invention is to provide an electrostatic image developing method that prevents film formation on an image forming member using cerium oxide and a cleaning blade, and that can provide high quality images free of fogging. shall be.

More specifically, it is an object of the present invention to form an electrostatic latent image on the surface of an imaging member by contacting it with a developer containing at least cerium oxide as particles independent of the imaging tail particles and toner particles. , forming a toner image on the surface of the image forming member, transferring the formed toner image to the outside of the transfer material, and cleaning the developer remaining on the surface of the image forming member after the transfer with a cleaning blade. There is an electrostatic charge image developing method.

Hereinafter, the present invention will be explained in detail while giving specific examples.

Generally, toner can be manufactured by the following method. As a binder, resins conventionally widely used in electrophotographic toners, such as polymers such as polystyrene, chlorinated paraffin, polyvinyl chloride, phenol resin, epoxy resin, polyester, polyamide, and polyacrylic acid resin, and These copolymers may be used alone or in combination of two or more.

A predetermined amount of various known dyes and pigments are added to this as a coloring agent, and the mixture is premixed using a vibration mill.The resulting powder is melted and kneaded using a roll mill, then coarsely ground using a hammer mill, and then finely ground using a jet mill. A toner having a particle size of 5 to 20p is used. Furthermore, the toner thus obtained is mixed with a carrier such as iron powder or glass beads, or the toner alone is used as a developer. One of the major features of the present invention is that a lubricant is added as an internal additive to the developer, and cerium oxide is added as an external additive. As a lubricant, sekibok, ummo, talc, chili stone, zinc oxide, molybdenum sulfide, polyethylene, polypropylene,
A wide variety of known materials can be used, such as resins such as polytetrafluoroethylene, higher fatty acid metal salts, higher fatty acid amides, higher fatty acid esters, paraffin wax, and silicone wax. Of course, these ladders are not limited to being used alone, and two or more ladders may be used in combination.

In the present invention, the lubricant is used internally in the toner, and the lubricant is added in an amount of approximately 0.05 to 20% (by weight) based on the weight of the toner. use.

In the present invention, in addition to the above-mentioned lubricant, cerium oxide is used as an abrasive in combination with toner particles and as independent particles, and also serves as a cleaning means.
This method uses a strong force and can easily remove toner film formation on the image holding member and secondary defects such as fogging. As such an abrasive material, cerium oxide is a suitable material in the present invention, considering conditions such as miscibility in the developer and hardly damaging the image holding member. In addition, the use of cerium oxide alone is not limited; cerium oxide and chromium oxide, aluminum oxide, calcium sulfate, barium sulfate, aluminum sulfate,
Calcium carbonate, magnesium oxide, calcium silicate,
It goes without saying that magnesium silicate and the like may be used in combination as long as they do not adversely affect the developing method of the present invention. Cerium oxide particles as abrasive particles are mixed with toner particles and, if necessary, with carrier particles, and are in the range of about 0.01 to 15% (by weight), particularly preferably 0.01 to 15% (by weight) based on the weight of the toner. It is used in a range of 5% (by weight). If it is less than 0.01% (by weight), there is almost no film formation prevention effect, and if it exceeds 15% (by weight), the effect of the lubricant will be canceled out, which is undesirable. Considering the problems such as polishing scratches on the image holding member,
It is preferable to set the weight in the range of 1 to 20 g.

Here, one embodiment of the present invention is illustrated as follows. That is, for example, polystyrene resin and oxygenated paraffin are used as the binding resin, and a predetermined amount of carbon black as a pigment and a lubricant such as polyethylene are added thereto. The powder is melted and kneaded in a roll mill, then coarsely pulverized in a hammer mill, and further finely pulverized in a dinit mill to obtain a toner having a particle size of about 5 to 20 liters.

The thus obtained toner is mixed with a carrier iron powder (e.g., trade name: EF300-500 (manufactured by S Hon Iron Powder KK)) and a cerium oxide abrasive in a ball mill or the like to mink sulfate (toner concentration 15%) to form a developer. shall be. The developer is, for example, a commercially available NP equipped with a cleaning blade.
5000 copier (manufactured by Canon KK) for copying, good results can be obtained. As the material of the cleaning blade, urethane rubber is preferable, and one having a JIS-A hardness of around 70@ is particularly preferable.The present invention will be understood more specifically from the examples shown below.

In the examples, the NP method is explained, but
The present invention is not limited to this, and can be effectively applied to other electrophotographic methods. In addition, the parts in the examples are shown in parts by weight unless otherwise specified.

Example 1 100 parts of silicone resin (binder resin), 10 parts of polystyrene
0 parts of carbon black, 9 parts of carbon black, 2 parts of Subiron black (dye), 2 parts of Danjo, 1 part of talc, and 0.5 parts of polyethylene.The above ingredients are thoroughly stirred and mixed in a Henshil mixer and pulverized. .

Next, this mixture was put into a roll mill and the temperature was 140-1.
After heating and melting at 50° C. for about 30 minutes and cooling to room temperature, the resulting melt was coarsely pulverized and then finely pulverized using a pulverizer to produce a toner having a particle size of 5 parts and 6 L. This toner is mixed with carrier iron powder and cerium infusate with a particle size ranging from about 5 to 10, toner/carrier/cerium oxide = 15 parts/85 parts 10,
They were mixed in a ratio of 1 part to form a developer. By applying this developer, -order QDC band 74. Se photoreceptor drum (support:
Au cylinder, photosensitive layer: evaporated Se, 60 l insulating layer;
The copying process was carried out using a urethane cleaning blade (hardness: 70°, angle to the insulating layer surface: 30°, blade load: 2, OKg), and the lubricity, image quality, and durability were evaluated. As a result of the test, the friction coefficient between the photoreceptor and the cleaning blade was 1.01, the drum rotated smoothly, and the image was good.
In particular, no change was observed between the initial image and the image density after 30,000 rotations, and even after 50,000 rotations, it was practical, and the tripopotential of the developer did not change, and the blade edge area Wear, damage, developer p”)
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The cerium oxide was removed from the developer composition of Example 1, and the copying process was exactly the same as in Example 1. Fusing of the toner was observed, and the image quality obtained was significantly degraded.

Example 2 Toner composition: 80 parts of polystyrene, 2 parts of phenol resin
0 parts, chlorinated paraffin 40 parts, carbon black 10 parts
1 part, Spirono black 2 parts, Danjo 2 parts, silicone wax 2 parts, and zinc palmitate 3.5 parts to prepare a developer in the same manner as in Example 1. As a result, the friction coefficient between the photoconductor and the cleaning blade was 1.01, the drum rotated smoothly, and the image was good, especially when the initial image and the 30 No change in image density was observed after 0.000 rotations, and even after 50.000 rotations, it was practical, and the tripopotential of the developer did not change. No film formation properties due to the fusion phenomenon were observed.

In addition, among the above compositions, only zinc palmitate was replaced with magnesium oleate, lead caprylate, calcium caproate, and copper lylunate, respectively.

The experiment was carried out in the same manner except that iron linoleate was used.
The copying results were the same.

As described above, according to the present invention, the lubricity on the photoreceptor and the abrasion resistance of the cleaning blade can be improved without impairing the characteristics of the toner, and at the same time, the photoreceptor can be improved by the fusion phenomenon of the developer. It is possible to prevent film formation on the body, remove the "turnip JJ phenomenon" of images, and permanently provide good images.

Claims (1)

[Claims] (1) Toner particles and toner particles containing an oil lubricant in an amount of 0.05 to 20% by weight based on the weight of the toner, forming an electrostatic latent image on the surface of the image forming member. A toner image is formed on the surface of the image forming member by contacting the particles with a developer containing at least cerium oxide as independent particles, the formed toner image is transferred to a transfer material, and after the transfer, the surface of the image forming member is An electrostatic image developing method characterized by cleaning residual developer with a cleaning blade.