JPS5870257A - Developing device - Google Patents

Abstract

PURPOSE:To obtain beautiful images free from unevenness by forming the down stream side in the developer moving direction of a magnetic blade for controlling the thickness of the developer of a nonmagnetic material and making the thickness of said nonmagnetic material larger than the thickness of a magnetic body. CONSTITUTION:A magnetic blade 3 is made of a magnetic material in part 7 thereof, and the part thereof nearer the rotating direction of a sleeve than said material 7, that is, the down stream side in the conveying direction of a magnetic toner is constituted of a nonmagnetic material 8. The part 7 is made thinner in thickness than the part 8, whereby the magnetic lines of force emitting from a magnetic pole S1 are concentrated to provide a higher effect of regulating the developer by the blade 3 and to concentrate the distributions of the magnetic lines of force near the blade 3 narrow.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a developing device, particularly a groove tube device using an insulating-component magnetic developer.

Conventionally, electrophotographic equipment and Lepoopsun! - latent image with an image forming device such as ll! To transfer, use l as shown in Figure 1.
The l1gI apparatus is used. In this first WJ device, a sleeve 2 having a fixed Madanet roll 1 inside
One-component magnetic toner in a hopper 4 is applied in a thin layer of 5 ft. using a magnetic blade 3 on the 0 surface. Magnetic toner 5Fi, magnet stomach - By the action of a strong static magnetic field created between the 8 layers of magnetic poles of #1 and the tip of the magnetic blade 6, a thin layer of toner of 50 to 200 layers is formed on the sleeve 2. .

However, as the sleeve 2 rotates, some of the toner in the developing device gradually aggregates to form a toner mass larger than the size of an individual toner. The toner is not conveyed by the rotation of the sleep 2, but is on the downstream side in the conveyance direction of the toner at the tip of the magnetic blade 3! It is attached at the position by the action of the magnetic field. If the agglomerated toner particles are no longer transported due to the rotation of the sleeve, and come into contact with both sides of the non-leap surface and remain there for a long time, the toner particles become saturated. Then, the layer of toner on the sleeve that has been thinly applied with the magnetic blade 3 is scraped off by this aggregated toner, and thin and pale portions of toner are created in the layer of toner on the sleeve.
This results in uneven coating, and the lii fl K after coating also has negative effects such as uneven streaks and uneven density.

SUMMARY OF THE INVENTION The present invention aims to eliminate the drawbacks of the conventional examples described above, and to provide a durable developing device whose developing characteristics do not change even after repeated use, and which is capable of producing uniform and clean images. It is something to do.

In order to achieve this object, the present invention installs a magnetic blade made of a magnetic material or a magnet that regulates the thickness of the @II agent in close proximity to the surface of the 1ilL sodium chloride carrier.
This is a developing device in which the downstream side in the direction of agent movement is formed of a non-magnetic material, and the thickness of the non-magnetic material is larger than the thickness of the magnetic material or magnet.

Embodiments of the present invention will be explained in detail below with reference to Figures mK.

FIG. 2 is a sectional view of a developing device according to an embodiment of the present invention.

Three magnetic blades of the present invention The part 7 is made of a magnetic material (11 stones are also possible), and the direction of rotation of the sleeve from the magnetic material 7 is
That is, the downstream side of the magnetic toner conveying direction is constituted by the non-magnetic material 8. As the magnetic material, iron, magnetic stainless steel, or steel filled with chrome metal is used.As the light valve magnetic material, aluminum, copper, copper alloy, etc. are used.

The thickness of the magnetic portion 7 of the magnetic blade 3 is preferably thinner than the thickness of the non-magnetic portion 8. By reducing the thickness of the magnetic portion 7 of the KIB blade 3 in this way,
By concentrating the lines of magnetic force coming out from the magnetic pole S1, the magnetic blade can increase the effect of regulating the current bolus agent, and the magnetic blade 3
K is 9 so that the distribution of magnetic force in the vicinity can be narrowly concentrated.

As a result, leakage of magnetic lines of force near the magnetic blade can be reduced, and the force that attracts the aggregated toner to the magnetic blade can be weakened. In addition, k is a non-magnetic material 8 such as aluminum 1, niu 5, etc. on the downstream side when looking in the first rotation direction of the sleeve of the magnetic blade.
By placing , the distance between the magnetic body portion 7 and the aggregated toner can be increased, and the force that holds the aggregated toner to the magnetic plate can be weakened.

Due to the above two effects, by weakening the force that attracts the agglomerated toner to the magnetic blade, the agglomerated toner can be easily separated from the magnetic blade by the rotation of the 9% press, and #! Figure 1! ◎ The present invention applies an alternating voltage between the sleeve 2 and the photosensitive drum 6 by a developing bias power source 9, and Sky 11 between the toner layer on 2 and the photosensitive dome 6
Japanese Patent Application Laid-Open No. 1983 (1973), which performs development by making toner fly back and forth at 1G.
It is most suitable for application to the developing devices described in Publications No. 18656 to 9, etc., but it is also suitable for devices in which a single layer of toner formed thinly on a sleeve (in contact with an image carrier such as a photosensitive drum) performs development. It can be applied to

As described above, according to the present invention, it is possible to remove large agglomerated toner particles that remain in the magnetic grade, and therefore, the number of toner particles on the sleeve is reduced, and good images can be obtained. At the same time, it has become possible to improve the durability of the toner.

[Brief explanation of drawings]

No. 1 wJ is a sectional view of a conventional developing device, and FIG. 2 is a sectional view W of an embodiment of the present invention. In the figure, 1...magne) w-two, 2@1
16@・Sleeve, 5...Magnetic blade, 4・e
- Hopper, 5... Magnetic toner, 7... Magnetic material portion, 8... Fist... Non-magnetic material, 9... Development bias power supply. Applicant Canon Co., Ltd.

Claims (1)

[Claims] Development gII in which a developer is held on the surface of a developer carrier, and this developer is brought close to or in contact with the surface of a health-retaining member to carry out an IA image.
In the fiI device, 1i is placed close to the surface of the developer carrier.
A magnetic blade made of a magnetic material or a magnet is installed to regulate the thickness of the developer, and the downstream side of the magnetic blade in the direction of developer movement is formed of a non-magnetic material, and the thickness of the non-magnetic material is adjusted to the thickness of the magnetic material or magnet. AM device characterized by being larger than the thickness.