JPS59111666A - Developing device - Google Patents

Abstract

PURPOSE:To develop a nondirectional, uniform picture without any brush trace by forming a delta-shaped developer bank among a latent image carrier, developer carrying member, and a specifying plate. CONSTITUTION:A nonmagnetic developing sleeve 3 is arranged fixedly facing the electrostatic latent image carrier 1 and a magnet roller 2 is provided therein rotatably. Then, the gap d2 between a doctor blade 4 and the developing sleeve 3 is made far larger than the gap d1 between the electrostatic latent image carrier 1 and developing sleeve 3 to allow a developer D to pass through the gap d2 smoothly, and the doctor blade 4 is arranged closely to the electrostatic latent image carrier 1 and developing sleeve 3. Thus, the amount of the developer passing through the gap between the carrier 1 and sleeve 3 is limited to bank the developer in a delta shape at a part A under the influence of the magnetic force of the magnet roller 2.

Description

[Detailed description of the invention] The present invention relates to a latent image developing device for electrophotography and the like.

In the generally widely used magnetic brush development method, a non-magnetic sleeve containing a fixed magnet is rotated, and a brush of developer consisting of magnetic Φ Yaya and toner is formed on the surface.
The electrostatic latent image is developed by rubbing. However, in devices using this method, the latent image is strongly rubbed with a brush, resulting in latent images caused by the rubbing of the brush (brush marks) and so-called directionality, where the density differs between the leading and trailing edges of the developed image. This causes the image quality to deteriorate.

Furthermore, development methods using one-component magnetic toner are known today, and the method using conductive toner is known as the MagneDry method, but this method makes it difficult to transfer the toner to the copying material, and the γ High quality and poor halftone image reproducibility.

Various developing methods using insulating magnetic toner have been considered, but the developing characteristics tend to become unstable due to changes in temperature and humidity, and γ becomes high, making it difficult to reproduce halftones. Generally, development using magnetic toner is not suitable for color development because the toner contains a brown or black magnetic material.

FIG. 1 is an enlarged view of the developing section of a conventional developing device, in which a doctor blade 4a provided opposite to the developing sleeve 3 and close to the latent image carrier 1 is used to increase the thickness of the developer layer on the developing sleeve 3. FJd between the electrostatic latent image carrier 1 and the developing sleeve 3
The developer is regulated to the same extent as +, and the developer is brought into contact with the electrostatic latent image carrier 1 for development. However, since the developer layer on the developing sleeve 3 is made up of carrier C and toner T in the form of a brush,
As shown in an enlarged view in FIG. 2, there are parts of the developer that do not come into contact with the electrostatic latent image carrier 1, and uniform development cannot be achieved.
Further, the β during contact with the developer was narrow, making it impossible to perform sufficient development, which was not desirable as a developing device.

The present invention has been made in view of the above points, and it is possible to obtain a uniform image without brush marks or directionality, to enable halftone development and color development using general non-magnetic toner, and to use a simple and compact device. The purpose of this invention is to provide a developing device.

In a developing device, the present invention includes an electrostatic latent image carrier, a non-magnetic sleeve provided with a gap from the latent image carrier, a rotating magnetic field generating means provided in the sleeve, and the sleeve and the non-magnetic sleeve. A developer carrying member provided between the latent image carrier and carrying the developer and conveying it to the gap; and a developer provided near the latent image carrier and spaced apart from the developer carrying member. It has a regulating plate, and is characterized in that a stable delta-shaped developer reservoir is formed between the latent image carrier, the developer carrying member, and the regulating plate in the development area to perform development.

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

FIG. 3 is an enlarged view of the developing device according to the present invention.

A non-magnetic developing sleeve 3 is located close to the electrostatic latent image carrier 1.
is fixedly arranged, and a magnet roller 2 with alternately magnetized N and S poles is rotatably provided inside the roller, and by contacting a magnetic carrier such as iron powder on the developing sleeve 3, a triboelectric charge is generated. When a developer mixed with insulating toner is supplied and the magnet roller 2 is rotated in the direction of the arrow, the developer on the surface of the magnet roller 2 moves in the opposite direction to the direction of rotation of the magnet roller 22, as is well known. The surface of the magnet row 22 is rotated in the direction B. In this way, in this device, the gap d between the doctor blade 4, which is a developer regulating plate, and the developing sleeve 3 is made sufficiently wider than the gap d between the electrostatic latent image carrier 1 and the developing sleeve 3, and the developing In addition, since the doctor blade 4 is provided close to the electrostatic latent image carrier 1 and the developing sleeve 3, the adhesive can sufficiently pass through the gap between the layers. The amount of developer passing through the gap is restricted, and the developer can be stored in a delta shape in the area A under the influence of the magnetic force of the magnet roller 2. At this time, Doctor Blade 4
As a result of experiments, it has been confirmed that when the particles accumulate to approximately the tip of the layer, the portion 9 no longer grows.

Furthermore, this reservoir portion A is located between the electrostatic latent image carrier 1 and the developing sleeve 3! Jdl changes, magnet low 22
It was confirmed that it is stable against changes in the rotational speed of the electrostatic latent image carrier 1, changes in the speed of the electrostatic latent image carrier 1, changes in the toner concentration of the developer, etc. Therefore, the development area α of the electrostatic latent image carrier 1 has a stable and constant width, and the developer p in the reservoir portion A comes into contact with the electrostatic latent image carrier 1 while being stirred by the rotation of the magnet roller 2. Therefore, sufficient development can be performed and uniform high-quality images can be created. The developer tank used for development is gradually discharged from the developing section α in the direction of the arrow B, and is generally replenished with toner and reused as necessary. By supplying developer with a constant toner concentration to the developing device, especially for color copies with good reproducibility, and collecting and disposing of the developer used for development, it is possible to perform development without changing the concentration. It is.

However, the developing device must function continuously by collecting and removing the developer after passing through the developing region, or collecting and reusing the developer. Therefore, the device shown in FIG. 4 can be considered as a simple collection mechanism. That is, the bottom of the developer storage container 5 is brought into contact with the fixed and immovable sleeve 3 to prevent the developer from passing over the developing area. However, since the developer is strongly restrained by magnetic force on the sleeve 3, even if it is regulated by the blocking part, it does not fall from the sleeve 3 immediately, but gradually increases the thickness t to which it is restrained. The part grows clockwise up to a certain angle θ. Then, the developer does not grow beyond a certain thickness, and after the thickness grows up to the upstream side of a certain angle θ, it is pushed by the developer fed in and falls from the lowest part g. Note that the developer layer on the downstream side (on the blocking portion side) of this falling position simply rotates on its axis on its own axis and does not undergo any metabolism with the developer fed in.

In addition, regarding the above angle θ, for example, the outer diameter is 32. Non-magnetic sleeve with 8 magnetic poles and 750 glass.

The developer is an iron powder carrier with an average grain size of 30μ mixed with toner at a toner concentration of 12 wt% (the toner is for Canon NP color copier), and MacNet Roller 2 is mixed with a toner of 300~
When rotating at 500 γ rpm, 8 mm in the middle and 60 in θ
It was °.

Therefore, even if the apparatus shown in FIG. 4 is provided with the recovery section 6 at the bottom as shown in FIG. It gradually becomes trapped and eventually overflows from the gap 6' between the sleeve 3 and the collecting section 6. Of course, downstream from the bottom, sleeve 3
Since the upper developer is not metabolized, it is not efficient to convey the developer in this portion by the conveyor 9.゛Therefore, there is a method for transporting the developer without having such drawbacks.
A compact developing device is shown below, which enables the collection and the purpose of the present invention of brush marks, uniform images without directionality, halftone development, and color development using general non-magnetic toner.

FIG. 6 shows a first embodiment of the present invention. 3A is the sleeve 3 in FIG. 3, which serves as a developer carrier. A non-magnetic rotating sleeve 3B, which is rotatably held by the drum-shaped electrostatic latent image carrier 1 with a gap d, is provided with a magnet roller 2 that rotates in the opposite direction to the sleeve 3B. There is. The developer carrier 3A is suitably in the form of a flexible or elastic resin film or a flexible metal plate, and has one end supported by the inclined wall 5' of the container 5, and is in close contact with the sleeve 3B. The end extends to the outside of Rat between the latent image carrier 1 and the sleeve 3B. Of course, it is also possible to apply a bias to the developer carrier 3A if necessary. Further, when the developer carrier 3A is made of a non-metallic material, the developer regulating plate 4 may be made conductive and a float developing bias may be applied.

In the region A formed by the leveling agent carrier 3A, the latent image carrier 1, and the developer regulating plate 4, the developer is distributed between the developer 3A and the latent image carrier 1.
After passing over the developing agent carrier 3A, it is carried directly on the sleeve 3B and conveyed to the back of the container 5. A scraper 11 is installed in the sleeve 3B at the back of the container 5.
is brought into contact with the screw conveyor 9, and the developer can be scraped off onto the screw conveyor 9 below. This recovers the developer.

According to an experiment, an 8-pole 750 gas magnet roller was used on a non-magnetic rotating slide with an outer diameter of 321 m, iron powder with an average grain size of 30 μm was used as a carrier, and Canon NP manufactured by Canon was used as a toner. Toner for a color copying machine was used at a toner concentration of 12wt, a film of approximately 50μ was used as the developer carrier 3A, the distance d between the developer carrier 3A and the developer regulating plate 4 was 1.5 fl, and the developer carrier When the distance d between 3A and the latent image carrier 1 is 0.7 m, and the non-magnetic rotating sleeve is rotated at 3 i'rpm, sufficient development can be achieved even if the rotation of the magnetic roller is changed from 3001r, pm to 50077-pm. It was a drug delivery. In addition, a stable developer layer was formed in the development area A. In this experiment, when the non-magnetic rotating sleeve was rotated at 10 rpm, the second embodiment of the present invention, that is, the conveyance in which the developer was accumulated in the upper part and formed p as shown in FIGS. 7 and 8. Showed strength. Further, there was no change in the developer droplets in the development area A, which was stable.

FIG. 7 shows a second embodiment. As described above, the non-magnetic rotating sleeve 3B is rotated at a speed sufficient to accumulate developer in the upper part thereof, and the toner is appropriately replenished from the hopper 8 and agitated by the stirring blade 7, and then used for development again. The developer carrier 3A is made of a thin elastic metal, and both ends in the axial direction are supported by a container, and the upper tip abuts against the non-magnetic rotating sleeve 3B to form a scraper. The non-magnetic rotating sleeve 3B transports all the developer on the non-magnetic rotating sleeve 3B and uses all of the developer for development, so that development deterioration is small and fluctuations in developer concentration can be reduced.

12 is the level detection of the developer. υIt is used to detect that only toner is consumed during development. It detects the change in the volume of the developer 1) and the developer P falls from the bottom due to the shock from the hopper. It's something I've earned.

FIG. 8 shows a third embodiment of the present invention. Figure 8 shows container 5.
The developer is scraped off by a scraper provided at the tip of the partition wall 5' inside, and the developer is sent to one side of the developing device by the screw conveyor 9. The developer is transferred to the side screw conveyor 10 and sent onto the developer carrier 3A fixed to the partition wall 5.An opening is also provided at the other end of the partition wall 5, and the screw conveyor 1
A portion of the developer is transferred from the container 0 to the screw conveyor 9, and the developer is circulated through the partition wall 5 to make the developer density uniform. A part of this circulation system is equipped with a toner supply section and a hopper 8.
Replenish the toner as appropriate from the machine and control the toner density.

According to the present invention, a stable delta-shaped developer reservoir is formed between the latent image carrier 1, the developer carrier 3A, and the part A of the developer regulating plate 4, and the developer used for development is transferred to the rotating body. It makes it possible to provide a sufficient conveyance force using magnetic force, which enables diversity in the development position or development device configuration, increases the amount of developer used, and stabilizes the toner concentration of the developer. It is something that makes it possible.

[Brief explanation of the drawing]

1 and 2 are enlarged views of a conventional developing device. FIG. 3 is an enlarged view of the developing device according to the present invention, FIGS. 4 and 5 are explanatory diagrams of the developer recovery state, FIG. 6 is a diagram of the first embodiment of the present invention, and FIG. 7 is a diagram of the present invention. Second embodiment of the invention, No. 8
The figure shows a third embodiment of the present invention. 1... Electrostatic latent image carrier 2... Magnet roller (magnetic field generating means) 3A.
...Developer carrier 3B...Non-magnetic rotating sleeve (sleeve) 4...
... Doctor blade; (developer regulating plate) 9 ... Screw conveyor (developer conveyance means) demand 5th wall~r

Claims (2)

[Claims] (1) An electrostatic latent image carrier, a non-magnetic sleeve provided with a gap between the latent image carrier and the latent image carrier, a rotating magnetic field generating means provided within the sleeve, and the sleeve and the latent image carrier. a developer carrying member provided between the developer carrying member and the developer carrying member for carrying the developer and conveying it to the gap; and a developer regulating plate provided near the latent image carrying member and spaced apart from the developer carrying member. What is claimed is: 1. A developing device comprising: , which performs development by forming a stable delta-shaped developer reservoir between a latent image carrier, a developer carrying member, and a regulating plate in a developing region. (2) Gap dt between the developer regulating plate and the developer carrying member
The developing device according to claim 1, wherein d is larger than the gap d between the latent image carrier and the developer carrying member.