JPS58140753A - Developer of electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To enhance fluidity of developer without impairing characteristics of the developer of small particle diameter, by mixing a carrier of large particle diameter with the small diameter developer. CONSTITUTION:A toner consisting of a styrene-acrylic resin, carbon black, and nigrosine, etc. and having 5-20, e.g., 10mum average particle diameter is mixed with a carrier of small particle diameter having 10-40, e.g., 25mum average particle diameter to form a developer having small particle diameter. Ferrite is coated with a styrene-acrylic resin or the like to form a carrier larger in size having 40-200, e.g., 100mum average particle diameter, and it is mixed with said developer of small size by <=50% of the total weight. Use of such a developer prevents its accumulation on a guide plate for returning it to a developer tank after development, and it can be returned to the tank even reducing an angle of the plate from the usual angle near 90 deg. to a considerably mild angle.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developer for an electronic copying machine in which fluidity is improved by mixing a large-particle carrier with a small-particle developer.

Conventionally, it is necessary to install a carrier having an average particle size of 10 to 40 .mu.m in a small particle size developer used in an electronic copying machine at an angle for mixing, which is subject to restrictions such as the position and internal structure of the developing device. In addition, the residual agent that accumulates on the wall of the guide plate comes into contact with the photoreceptor and disturbs the image on the photoreceptor surface, or adheres to the surface of the photoreceptor and causes background stains. The developer C deposited on the guide plate is forcibly dropped into the developer tank d by providing such a diaphragm α, and the structure becomes complicated because the diaphragm α is required.

Furthermore, since the small-diameter carrier itself is small in weight, there is no force to destroy it even if it is blocked in the developer tank d, so it is necessary to use a material that is difficult to block. A friend who has problems such as

The present invention was made with the aim of improving the above-mentioned problems, and it provides a developer for small-particle photographic machines by mixing a small-particle developer with a large-particle carrier having an average particle size of 40 to 200 μm. The objective is to improve the fluidity of the particle-sized developer without impairing its characteristics.

One embodiment of the present invention will be described in detail below. Styrene acrylic resin 30 Mt% and magnetite EPT 1000
(Japanese iron powder n) 7011zt, a small particle carrier with an average particle diameter of 25μ, styrene acrylic resin,
The average particle size of carbon black and nigrosine is 1
A small particle size developer is formed by mixing toner with a particle size of 0μ, and a developer is prepared by coating a ferrite with styrene acrylic resin and mixing with a large particle size carrier having a 100μ average particle size, and a flow test of this developer is performed. As a result, the results shown in Figure 2 were obtained.

As a test method, an aluminum plate with no scratches on the surface was placed horizontally, and a 20 t sample of the developer was dropped onto the plate using a spa chiller.

After that, tap the aluminum plate several times with your finger to smooth out the piles of samples on the aluminum plate so that they have a uniform density, then tilt the aluminum plate and measure the angle at which all the samples on the plate slide down. Figure 2 is a diagram showing the results.

t72. In order to confirm the image quality obtained by copying, large particle carriers with an average particle diameter of 100μ were gradually added to the small particle developer described above, and changes in both values were examined, and it was found that the proportion of large particle carriers was 50wt4. Lines began to appear in the copies obtained from nine hits. As a result, it was confirmed that the proportion of large particle carriers should be less than 50% of the total weight.

Furthermore, in order to investigate the presence or absence of developer blocking that occurs in the developer tank, a developer prepared by adding 5 Q wt @ large particle carrier with an average particle size of 100μ to a small particle developer was charged into the bleeder for 100 hours. After nine rotations, there was no blocking at all.

From the above, it can be seen that the components of the developer of this invention have an average grain size of 5
A small particle size developer is formed by mixing a small particle size carrier with an average particle size of 10 to 40μ to a toner consisting of ~20μ, and a large particle size carrier with an average particle size of 40 to 200μ is added to this by 5% of the total weight.゜Yu and below added Kamenotoshirin. Please use this developer.
When actually used in a copying machine, due to the improved fluidity, the developer did not accumulate on the guide plate that returned the developer to the developer tank after printing, and the guide plate was placed at right angles. The developer can be returned to the developer tank sufficiently even at a gentler angle than a close angle, and there is no longer a need for a photographing means for forcibly knocking off the developer accumulated on the guide plate.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional developing device, and FIG. 2 is a diagram showing test results of a developer according to an embodiment of the present invention. Applicant: Fuji Xerox Co., Ltd. Agent: Patent attorney: Masaaki Yonehara Patent attorney: Tadashi Hamamoto Figure 2 Figure 7; Hiji Sunjin (uJIX)

Claims (1)

[Claims] Toner with an average particle size of 5 to 20 μm has an average particle size of 10 μm.
An electronic copying machine in which a small particle size carrier having an average particle size of ~40μ is mixed to form a small particle size developer, and a large particle size carrier having an average particle size of 40 to 200μ is mixed therein in an amount of not more than 50% of the total weight. developer.