JPS58116559A - Developing device - Google Patents

Abstract

PURPOSE:To apply a constant amount of toner uniformly and stably without any streak and irregularity on a developing roll by arranging a coating blade where the toner falls by gravity. CONSTITUTION:A rubber blade 7 is provided on a side where the toner is scooped up onto the developing roll 3, and the end part of the blade 7 causes the toner to fall along the developing roll 3 or in the air. When the contacting point between the end part of the blade 7 and the roll 3 is provided more left on the developing roll 3 than the vertical line running in the center of the developing roll 3, more toner stays in the space A surrounded by the blade 7 and developing roll 3. The toner tends to stay ununiformly in the lengthwise direction of the roll and also tends to increase in layer thickness, but the blade 7 is fitted where the toner falls, thereby preventing those phenomena.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for developing an electrostatic image formed on the opposite surface of an electrostatic image carrier, and in particular, a device for developing an electrostatic image formed on the opposite surface of an electrostatic image carrier. The present invention relates to an apparatus for forming and developing .

Generally, when an electrostatic image is developed using a dry developing agent, it is extremely important to control the first toner on the toner holder in order to obtain a good toner image storage. Particularly in contact development, MagneDry development, and Jean development using -component toners, it is essential to sufficiently control the toner thickness.

Conventionally, in order to uniformly apply toner to the toner holder, a toner thickness regulating blade was placed so as to maintain a predetermined gap from the surface of the toner holder. was commonly used. However, with this method, it was not possible to regulate the thickness of the toner 1- on the surface of the toner holder and on the toner thickness regulating plate V-. This is because even if the toner particles lie down when the toner passes through the gap, they rise up after aa.
The actual layer thickness will be greater than the gap - Cl,
This is because the formation of a thin layer of ligament results in the formation of a tame. Also,
The agglomerated toner particles that happen to have formed a part of the gap between the toner thickness regulating blades close up, and the phenomenon becomes impossible in that area, resulting in a white streak at the first interval of the image after the phenomenon. ) During development, toner k'? l (
It is known that a coating planar coated on the entire surface of velvet, velvet, etc. is used in order to achieve T+, but this results in the mixing of hair, etc. into the agent.

This had a negative impact on the current situation.

Therefore, in one-component development using magnetic 1:t toner,
For example, a magnetic material plate is placed near the toner holder, facing the magnet provided inside the toner holder. Apply and form a thin layer of toner (2 layers).

In one-component development using non-magnetic toner, since magnetic field metal cannot be used for C, the conventional regulating blade described above is used, or the toner holder surface (1'+117C) is applied with the application blank described above. and uniform −']ji jit ('−J
Efforts have been made to increase the thickness of the toner coating layer.The present invention is a one-component slurry device that improves the drawbacks listed below.
The one-component developer rtVcv, which uses high-resistance non-magnetic toner gold, has a compact and simplified developer configuration and can stably and uniformly apply toner, resulting in images with sufficient clarity and gradation. The object of the present invention is to provide a novel developing device which makes it possible to obtain image copies that are free from tonality, streaks, and unevenness.Hereinafter, embodiments shown in the drawings will be described.

FIG. 1 is a cross-sectional view of an apparatus according to an embodiment of the present invention;
is an electrostatic image carrier depending on the electrostatic image forming method -C4'ilt
It is composed of an insulator provided on a transparent substrate, or a photoreceptor having a photoconductive layer. The electrostatic image formation on one side of the electrostatic image carrier is performed by a photographic processing means or an electrostatic recording means (not shown).O2 indicates the entire developing apparatus according to the present invention. 3 is a developing roller forming a toner holding body, which is made of a non-magnetic sleeve (for example, a cylinder made of aluminum/stainless steel) and is supported so as to be able to rotate once;
It is rotated in the arrow aj5 direction by a drive source (not shown). The surface of the toner holding body 2 is provided with concavities and convexities of 2 to 5 microns in order to ensure toner retention. The component-based non-magnetic toner 4 is stored in a hopper 5, and this hopper is arranged 11 below the developing roller 3. The toner is supplied onto the two-C developing roller 3 by a pumping roller 6. Note that the roller 6 also stirs the toner in the hopper 5 and the toner image on the roller after being mixed.The toner on the roller that has been pumped up is regulated by the end of the rubber blade 7. applied. It is preferable to use a rubber blade made of a material of the Ill triboelectric series suitable for charging the toner 1 to a desired polarity. For example, in order to positively charge a toner whose composition component is polyste V/, carbon, etc., the toner material 'JtV (- depends on the composition), and in order to charge it negatively,
When a suitably selected conductive rubber is used in silicone rubber or poly triboelectrification series, it is possible to prevent the toner from being excessively triboelectrostatically charged, thus preventing electrostatic agglomeration or assimilation of the toner. Enjoy the relaxing effect.

A rubber blade is provided just before the toner is pumped onto the developing roller. This is because the excess toner is regulated by the end of the blade and falls by gravity along the current roller or into space. For example, from the vertical line passing through the center of the developer roller in FIG.

When a contact point between the blade end and the developing roller is provided on the upper left side developing roller, a toner pool is formed in the space A between the blade and the developing roller. This pool is often formed non-uniformly in the longitudinal direction of the developing roller.

For example, in a portion where a large amount of accumulation is formed, the toner becomes thicker. Of course, if the blade pressure is increased, a constant thickness of toner can be obtained almost regardless of the buildup, but this creates a gap between the blade and the developing roller, and the toner gets clogged in this area, resulting in the above-mentioned toner agglomerates and the coating streaks. occurs.

The present applicant previously proposed in Japanese Patent No. 54-43038 a development device in which toner is applied by pressing the belly of a rubber blade against a developing rubber roller. The same is true in the case of - mode, where a narrow space is formed between the blade and the developing roller, causing streaks and unevenness. Also.

Japanese Utility Model Application Publication No. 53-30339 discloses a method in which the tip of the blade is brought into contact with toner on a rubber roller serving as a developer carrier.
An example of applying a friction band* to the toner is shown, but since the toner is applied to this roller from a hopper placed above the developing rubber roller, the toner is in the space formed by the rubber roller and the blade. They tend to accumulate, which can lead to the aforementioned drawbacks.

In the examples of the present invention, the surface of a 32 mm aluminum sleeve was roughened with a No. 600 tend paper to create a rough surface with 2 to 3 tt unevenness. As a rubber blade, thickness 2u width 20.1111
600 rubber was once used in urethane with dimensions and shape of . Regarding hardness, when the dimensions and shape are changed, it is 5aζ80'
is effective and rare.

My father, the non-magnetic toner used at this time was a powder with a particle size of 7 to 15 microns, mainly consisting of 10 parts of carpon and 90 parts of polystyrene, and about 0.5 times of -C silica was added as an external additive to give the toner fluidity. Gave. Figure 1 1-) J8 has toner currently 1a
A thin Mylar (trade name) sheet was used to prevent the formation of ridges from the container. The contact pressure of the rubber blade against the developing roller is effective to be approximately 5 to 2511/ltn when the hardness, dimensions and shape of the blade are changed, and it is preferable to keep the error within 5 in the longitudinal direction of the roller. The experimental row was set to about 15 tlc genus. As the pumping roller 6, a brush roller with a thickness of about 5 deniers and a length of about 10 mm was used.As a result of conducting the experiment in this way, it was found that the developing roller 3 had a brush roller with a thickness of 50 to 100 μ without any streaks or unevenness. A single thin layer of Itona could be formed. By changing the blade pressure, the toner layer thickness can be changed.

Incidentally, as the surface roughening treatment, known means such as sandblasting and liquid homing can be used/IE. It is also effective to form a relatively rough surface of about 4 to 5 mm with abrasive grains of No. 300 to No. 400 or sandpaper. By bending the surface of the developing roller, the conveyance of the toner is improved.
It has the advantage of being more likely to cause triboelectric damage to the toner when in contact with -E, and less likely to cause streaks and unevenness when toner is applied with a rubber pad.

The thickness of the toner I- on the developing roller is made smaller than the length of the facing gap between the gap filler roller and the photoreceptor, and the toner is moved from the developing roller to the photoreceptor within the gap to perform -C development (also referred to as ``Wi jumping''). In the embodiment in which a developing image is to be developed, even better quality images can be obtained by applying a full developing bias between the photoreceptor and the developing roller using a bias power source 9 to apply a direct current or alternating electric field or a direct current electric field RIL to an alternating electric field. You can dive. For example, for a shield where the dark part + 600 V% bright part is Ov, the gap between the photoreceptor and the developing roller is kept at about 300 μ, and the toner layer L1 [is regulated at 50 μ].
A of 2KVp ps 2Kllz on C1 developing roller,
0. Applying a voltage with a DC voltage of +150V superimposed on the voltage, -C development is carried out, and the voltage is 1f5.
r: There was an increasing effect. //) The present invention can also be applied to conventionally known contact type hoe devices.

What is the angle of the blade setting position in the present invention?

Although it varies slightly depending on the fluidity of the toner used and the surface properties and radius of curvature of the developing roller used, for general commercial toner, the distance from the vertical line B passing through the center of the developing roller is as shown in Figure 2. Angle θ to the blade contact point C to the pumping side.

is 0 < 6. < 180°, and assuming a virtual developing roller and assuming that the blade does not deform (indicated by the broken line in Figure 2), this developing roller, blade, and OM! ! Point C
The angle θ from the tangent to the developing roller passing through ′ is 0〈θ,
<1800 is preferable, and in this example, preferably 30
Good results were obtained by setting °〈θ1.30°〉〉〈90''.

1: As described in detail, according to the present invention, it is possible to perform the current toner-heavy process stably, and 4I copying can always obtain a stable density and produce long, high-quality images. It will be done.

Furthermore, the developing device is simplified and can be applied to a developing device using color toner that does not contain magnetic material, which is also useful for low-cost color printers. Of course, the present invention can also be applied to a present invention device that uses magnetic toner and conveys the magnetic toner using a magnetic roller and a sleeve.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the developing device according to the present invention, and FIG. 2 is an explanatory view of the angle of the coating blade. DESCRIPTION OF SYMBOLS 1... Photoreceptor, 2... 1-image device, 3... Actual roller, 4...-component type non-magnetic toner, 5... Holacoo. 6... Pumping roller % 7... Rubber pad, 8
...Member for preventing toner scattering, 9... (Represents Iasumi source.) Applicant: Canon Co., Ltd. W!! Clothes Nade

Claims (1)

[Scope of Claims] (1) A developing roller disposed opposite to the layered image carrier;
A toner supply means disposed below the developing roller for supplying component toner to the developing roller, and a developer application blade provided between the toner scooping whiskers, the application blade being It is made of an elastic material, and its edge portion is brought into contact with the developing roller in the forward direction relative to the moving direction of the developing roller, and is placed at a position where the toner falls by gravity so that the toner does not accumulate in the space formed by the blade and the developing roller. A developing device characterized by disposing a coating blade. (2) The surface of the developing roller is formed into a rough surface.
[The phenomenon device according to claim 1, characterized in that: 1:l) The angle θ formed by the vertical line passing through the center of the four-image roller and the contact point between the coating blade and the current single-stage roller is 30″ (θ). The phenomenon device according to claim 1 or 2. (4) The device according to any one of claims 1 to 3, wherein the - component toner is a non-magnetic insulating toner. +5) The developing device according to any one of the first to fourth toners on the latent adhesion holder and the toner roller.