JPH0862893A - Toner - Google Patents

Abstract

PURPOSE: To stably form a high quality image even when a polymerized toner is used in the developing unit of a copying machine or a printer adopting an electrophotographic system by perfectly removing a residual toner with a blade disposed in the cleaning part and preventing the contamination of other process. CONSTITUTION: A toner obtd. by mixing a polymerized toner with a proper amt. of a pulverized toner is used as the toner used for development. At this time, the application of a blade cleaning system as a cleaning system is enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner (developer) used in an electrophotographic copying machine or a developing device of a printer.

[0002]

2. Description of the Related Art FIG. 2 is a cross-sectional view showing a main part of a conventional electrophotographic printer, in which a photosensitive drum 1 is uniformly charged by a charging brush 2 as a charging unit and subsequently charged by a laser beam 3. To disappear to form a latent image. After reducing this latent image by the developing unit 4,
The transfer roller 5 transfers the toner image onto the paper 6,
Pass it through the fixing device (without drawing) to fix it.

The toner 9 remaining on the photosensitive drum 1 without being transferred to paper moves to the cleaning unit 7. Here, the fur brush 7b brought into contact with the photosensitive drum 1 scrapes off the toner 9 remaining on the photosensitive drum 1. After that, the charge on the photosensitive drum 1 is erased by the neutralization light 8, and the process proceeds to the charging step again.

In this process, the charging brush 2 is used as a unit for uniformly charging the photosensitive drum 1, and the transfer roller 5 is used as a toner image transfer unit. Since all of these units are in contact with the photosensitive drum 1,
The performance of the photosensitive drum 1 can be significantly reduced due to the contamination of the photosensitive drum 1. In particular, the deterioration of the charging ability due to dirt on the charging brush 2
Remarkably reduces the image quality. Also in the developing unit, a one-component contact type developing system has been developed in recent years and tends to be easily affected by dirt on the photoconductor.

Toner (developer) in the developing unit 4
4b has been made smaller in particle size with the recent improvement in image quality, and a part thereof manufactured by a polymerization method is also used. The toner produced by the polymerization method has a uniform particle size, and a nearly spherical shape can be obtained. Therefore, the charging property is uniform, the reducing property is good, and the transfer property is excellent. However, as an adverse effect due to the shape being close to a sphere, defective cleaning easily occurs due to slipping through the blade during cleaning by blade cleaning.
As a countermeasure, a fur brush 7b, which is a cleaning method other than blade cleaning, is used, or the toner is deformed.

[0006]

When a polymerized toner is used, the cleaning method cannot be changed to an inexpensive blade method, resulting in an increase in cost, and an increase in cost and a decrease in performance due to deforming the toner. Was causing.

[0007]

In order to solve the above problems, the present invention provides a polymerized toner (first toner) produced by a conventional polymerization method and a pulverized toner (second toner) produced by a pulverization method. Development is performed using a mixture of a proper amount of toner) as a toner (developer).

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention and is a sectional view of the main part of an electrophotographic printer. The processes of charging, exposing, developing, transferring, discharging, and cleaning are arranged around the photosensitive drum 1. A fixed charging brush 2 is used for charging, and a charging voltage VB is applied. After charging, the toner image is developed by selective irradiation of the laser beam 3. This toner image has a transfer bias V
It is transferred onto the paper 6 which is a recording medium by the transfer roller 5 to which T is applied. The transferred toner image is fixed by a fixing device (not shown), and printing is completed.

At this time, the toner 9 and other residues remaining without being transferred onto the photosensitive drum 1 move to the cleaning unit 7. Here, the toner 9 remaining on the photosensitive drum 1 is scraped off by the flexible blade 7a brought into contact with the photosensitive drum 1. After that, the charge on the photosensitive drum 1 is erased by the discharging light 8 and the process proceeds to the charging step again.

The toner 4a used in the developing unit 4 is a mixture of the toner produced by the polymerization method and the toner produced by the pulverization method in an appropriate amount.

The mixing ratio of the pulverized toner to the polymerized toner is 50% at maximum, preferably 20 to 40%. The composition of the polymerized toner and the composition of the pulverized toner may be the same, or even different compositions can be adjusted within a range that does not adversely affect other image characteristics or the photosensitive drum.

As the polymerized toner, a toner having a shape close to a sphere and having a uniform particle shape has been developed. Since it exhibits excellent developability and excellent transferability, the toner 9 remaining on the photosensitive drum 1 is too much. There is no. However, since it is close to a spherical shape, it passes through the cleaning blade 7a more frequently. Further, since the pulverized toner is indefinite in shape and stretched, the developability and transferability are inferior to those of the polymerized toner, but the cleaning ability by the cleaning blade is good. Therefore,
By selecting the mixing ratio of both to be 20 to 50%, it becomes possible to scrape the polymerized toner together with the pulverized toner in the cleaning blade portion between the cleaning blade and the photosensitive drum.

[0014]

With the toner composition as described above, the cleaning effect of the blade can be improved, and the cost of the apparatus or process cartridge can be reduced. In addition, it is possible to stably obtain a high-quality image for a long period of time without impairing the characteristics of the polymerized toner.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of an electrophotographic printer using a toner of the present invention.

FIG. 2 is a cross-sectional view showing a main part of an electrophotographic printer using a conventional polymerized toner.

[Explanation of reference numerals] 1 photosensitive drum 2 charging brush 3 laser light 4 developing unit 4a mixed toner of polymerized toner and pulverized toner 4b polymerizing roller 5 transfer roller 6 paper (recording medium) 7 cleaning unit 7a cleaning blade 7b fur brush 8 neutralizing light 9 Residual toner

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Claims (2)

[Claims] 1. A toner (developer) used in a phenomenon process of an electrophotographic apparatus, which is a mixture of a first toner having a nearly spherical shape produced by a polymerization method and an amorphous second toner produced by a pulverization method. 2. The method according to claim 1, wherein the first toner produced by the polymerization method is mixed with the second toner produced by the pulverization method at a ratio of 50% at maximum. toner.