JPH0540525Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a developing device, and in particular, to a developing device, in which a one-component developer supplied onto a developer carrier is formed into a developer layer of a predetermined thickness by a regulating member, and this developer layer is The present invention relates to a one-component developing device that develops a visible image by electrostatically adhering it to an electrostatic latent image.

Conventional technology A developing device for developing an electrostatic latent image formed on an electrostatic latent image holder has conventionally used a two-component developer consisting of toner and a carrier, and is charged by frictional charging with the carrier. Two-component developing devices that electrostatically attract toner to an electrostatic latent image have been actively developed and put into practical use. Although two-component developing devices are sufficiently practical, a one-component developing method and device using a one-component developer consisting only of toner has been proposed in order to make the developing device itself more compact and easier to maintain. Among these, a one-component developing method using a non-magnetic toner is desired from the viewpoint of high transparency of the toner in response to colorization.

As a non-magnetic one-component developing method, the tuck-down developing method disclosed in U.S. Pat. No. 2,895,847 is generally well known. There is. Although this method is easy, it has many drawbacks, such as the large size of the device and the need to periodically clean the corotron wire. A non-magnetic one-component developing device was previously proposed in which a thin layer of developer is formed on a developer carrier by a regulating member that is in pressure contact with the developer carrier, and a charge of a desired polarity is applied to the developer.

FIG. 4 is a schematic diagram showing an example of the above-mentioned one-component developing device, in which the developer 4 accommodated in the hopper 6 is carried on the developer carrier 1 by the rotation of the developer supply member 2. , is formed into a developer layer 7 of a predetermined thickness by the regulating member 3, and is triboelectrically charged;
It electrostatically attracts an electrostatic latent image formed on an electrostatic latent image holder (not shown) such as a photosensitive drum disposed opposite to the developer carrier 1 and develops it into a visible image. .

Problems to be Solved by the Invention However, in the developing device having such a configuration, the pressure due to the gravity of the developer 4 housed in the hopper 6 tends to lift the regulating member 3 from the developer carrier 1. Since it acts in the direction indicated by C in the figure, the contact pressure between the regulating member 3 and the developer carrier 1 may change depending on the amount of developer contained therein. When this contact pressure changes, the thickness of the developer layer 7 on the developer carrier 1, which is determined by the contact pressure, also changes, making it difficult to perform stable development. Furthermore, when this type of developing device is applied to a high-speed copying machine, the developer consumption rate increases and a large hopper is required, which increases developer pressure fluctuations and makes the above problem even more pronounced. Summer.

The present invention was developed in view of this problem, and its purpose is to provide a one-component developing device in which the pressure of the developer against the regulating member changes little even if the amount of developer stored in the hopper changes. Our goal is to provide the following.

Means for Solving the Problems The one-component developing device of the present invention includes a hopper that holds a one-component developer inside and has an opening at the bottom, and an electrostatic latent image holding surface that has an electrostatic latent image formed on its surface. a developer carrier provided in the opening adjacent to the body; a regulating member having one end fixed to a wall surface of the hopper forming the opening and the other end pressed against the developer carrier; a developer supplying member that contacts the developer carrier while being embedded in the developer carrier and rotates in a direction opposite to the rotational direction of the developer carrier; and a pressure relief member, one end of which is connected to the hopper. The regulating member is fixed in the vicinity of a portion of the wall surface to which the regulating member is fixed, and the other end is located below the contact portion between the regulating member and the developer carrier and approximately directly above the developer supplying member.

According to a preferred embodiment of the present invention, the pressure relief member can be constructed of a baffle-like member extending from the vicinity of the portion of the hopper wall where the regulating member is fixed.

Function The developer carried by the regulating member in a predetermined layer thickness on the developer carrier is electrostatically attracted to the electrostatic latent image formed on the electrostatic latent image holder during development, and the developer is absorbed into the latent image. Only the corresponding amount will be consumed. Accordingly, the amount of developer contained in the hopper decreases. In the developing device of the present invention, since the pressure relief member is provided in a specific form as described above, even if the amount of developer that behaves as powder changes, the pressure change is alleviated by the pressure relief member. Therefore, the pressure applied to the regulating portion remains almost constant regardless of the amount of developer. As a result, a developer layer with a constant thickness is always formed on the developer carrier regardless of the amount of developer in the hopper.

Embodiment A preferred embodiment of the present invention will be described in detail below with reference to the drawings. Parts with substantially the same function and structure as the conventional example shown in FIG. 4 will be designated by the same reference numerals. do.

FIG. 1 shows a typical example of a one-component developing device to which the present invention is applied, in which a developer 4 is accommodated in a hopper 6. The developer 4 is particles with a size of about 5 to 20 μm in which a pigment such as carbon black or a polarity control agent such as a metal-containing azo dye is dispersed in various thermoplastic resins such as styrene or acrylic resin. Typically, 0.5 to 2% hydrophobic silica is added. At the lower part of the hopper 6, a developer carrying member 1 and a developer supplying member 2 are pivotally supported so as to be in pressure contact with each other, and are adapted to be rotated by a rotation driving means (not shown).
The developer carrier 1 is constructed by coating a conductive cylindrical member such as SUS material with a phenolic resin.
The developer supply member 2 is constructed, for example, by covering a similar cylindrical member with a rubber layer. 3 is for example
This is a regulating member made of a plate spring material such as SUS material that does not easily undergo plastic deformation. One end of the regulating member is fixed to the hopper 6, and the other end is pressed against the developer carrier 1 by the elastic force of the plate spring material itself. are doing.

The developer 4 adheres to the developer carrier 1 in a predetermined layer thickness by the regulating member 3 to form a developer layer 7, and is charged by frictional charging. This developer layer 7
is sent to an electrostatic latent image carrier (not shown) such as a photosensitive drum by the rotation of the developer carrier 1, and is electrostatically attracted to the latent image to develop it into a visible image. Note that the developer layer 7 that is not used for development, that is, the developer 4
is removed from the surface of the developer carrier 1 by the developer supply member 2 and returned to the hopper 6.

5 is a pressure relief member characteristic of the present invention,
It is formed into a plate or mesh shape. One end of the pressure relief member 5 is fixed near the wall surface of the hopper 6 to which the regulating member 3 is fixed, and the other end extends almost directly above the developer supply member 2, and its inclination angle with respect to the vertical direction is It is desirable that the temperature be set to less than 60 degrees.

Next, various amounts of developer are stored in the one-component developing device having the above-mentioned configuration and the device is operated to obtain the amount of developer on the developer carrier (hereinafter referred to as the amount of developer carried). I looked into it. FIG. 2 is a graph comparing the relationship between the amount of stored developer and the amount of developer carried in cases where a pressure relief agent is provided and cases where a pressure relief agent is not provided. The numbers on the horizontal axis of the graph correspond to the numbers attached next to the dashed-dotted line shown in FIG. 3, and indicate that the average level of the upper surface of the area occupied by the stored developer is at the position of the dashed-dotted line. , the vertical axis indicates the amount of developer carried. The results shown in Figure 2 show that when the contained developer is at level 1,
This was obtained by setting the pressure of the regulating member so that the amount of developer carried was 0.7 mg/cm ² .As is clear from the graph, when the pressure relief member is not provided, the contained developer The amount of developer carried varies by approximately 0.4 mg/cm ² depending on the amount of developer, but when a pressure relief member is provided, the amount of developer carried varies from 0.6 to 0.8 mg, which is optimal for development conditions. It can be seen that it is stable within the range of / ^cm2 .

Effects of the Device As detailed above, according to the present invention, fluctuations in the pressure of the developer contained in the hopper are less likely to directly affect the regulating member, and the developer can be carried at a constant level regardless of the amount of developer. This has the effect of making it possible to obtain more quantity. As a result, the optimal developing conditions can be maintained until the amount of developer stored is small, and the amount of developer stored can be used for development, making it possible to downsize the apparatus. Therefore, if the one-component developing device of the present invention is incorporated into a general electrophotographic copying machine, it will be advantageous in terms of stability and miniaturization of the device. It goes without saying that the present invention can also be applied to recording devices other than copying machines, such as printers.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the configuration of a one-component developing device showing a preferred embodiment of the present invention, and FIG. 2 is a graph showing the relationship between the amount of developer carried and the amount of developer accommodated in the hopper. FIG. 3 is an explanatory diagram of the amount of developer contained in the hopper. FIG. 4 is a sectional view showing an example of a one-component developing device. 1...Developer carrier, 2...Developer supply member,
3...Regulating member, 4...Developer, 5...Pressure relieving member, 6...Hopper, 7...Developer layer.

Claims (1)

[Scope of utility model registration request] a hopper containing a one-component developer therein and having an opening at the bottom; a developer carrier provided in the opening adjacent to an electrostatic latent image carrier having an electrostatic latent image formed on its surface; , one end of which is fixed to the wall surface of the hopper forming the opening, and the other end of which is in pressure contact with the developer carrier; comprising a developer supplying member that rotates in a direction opposite to the rotational direction of the carrier, and a pressure relief member, one end of the pressure relief member being fixed near a portion of the wall surface of the hopper to which the regulating member is fixed; A one-component developing device, wherein the other end is located below a contact portion between the regulating member and the developer carrier and substantially directly above the developer supplying member.