JPS5926022B2 - Development method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for developing an electrostatic latent image.

An electrostatic latent image formed on recording paper in a receiving section of a facsimile machine or an electrostatic latent image formed on a photoreceptor in an electrophotographic copying machine or recording device needs to be developed.

As a means of visualizing an electrostatic latent image, magnetic toner is transferred to the electrostatic latent image using a fixed sleeve made of a non-magnetic material and a magnet roller rotatably disposed inside the sleeve. Supply to the statue.

There is a so-called magnetic brush developing device. Such a developing device is
Toner is held in a brush shape on the circumferential surface of the sleeve, and the brush height is controlled by a doctor plate, and then the toner is supplied to the electrostatic latent image carrier. One of the factors that influences the function of such a developing device is that the distance between the sleeve and the electrostatic latent image carrier must always be kept constant and very small.

If the electrostatic latent image carrier is provided with rigidity such as a photoreceptor drum, the above-mentioned distance can be maintained without any problem. However, if the electrostatic latent image carrier is flexible, such as recording paper or an endless belt, it is necessary to take some measures.

Referring to FIG. 1, an example of a developing device equipped with means for maintaining a distance between a flexible electrostatic latent image carrier and a sleeve will be described. In the figure, reference numeral 1 indicates a fixed sleeve made of non-magnetic material.

Inside the sleeve 1, a magnet roller 12 is rotatably provided with north and south poles arranged alternately in the circumferential direction, and is rotated in the direction of the arrow by a drive mechanism (not shown). It will be done. A toner container 3 containing toner is disposed below the sleeve 1. When the magnet roller 12 rotates clockwise, the toner T in the toner container 3 is fixed on the surface of the sleeve 1 and moved counterclockwise.

The height of the toner T magnetically adhered to the surface of the sleeve 1 in the form of a brush is controlled by a doctor plate 4.
On the other hand, a gear roller 5 is rotatably disposed at a predetermined distance from the sleeve 1.

The gear roller 5 is made of a conductive material.
In the illustrated example, the gear roller 5 guides the recording paper 6 of the facsimile transceiver. An electrostatic latent image is formed on the recording paper 6 by a suitable electrostatic latent image forming means 7. Further, the recording paper 6 is moved in the direction indicated by the arrow by a conveyance device (not shown). Recording paper 6
When the sleeve 1 moves, the toner T on the surface of the sleeve 1 is supplied to the electrostatic latent image on the recording paper and develops it.

The distance between the recording paper 6 and the sleeve 1 is maintained by a gear roller 5. By the way, in the device shown in FIG. 1, the distance between the sleeve machine and the guts roller 15 is
It is necessary to reduce this and maintain parallelism with each other, but it is difficult to adjust and the adjustment range is narrow.
The precision of other parts, such as the support member for the gear roller 15, must be improved, resulting in a problem of increased costs.

Furthermore, when the recording paper is fed intermittently, there is a drawback that uneven development and background stains are more likely to occur. That is,
When the recording paper 6 is stopped while toner T is present on the surface of the sleeve 1, many layers of toner will be deposited on the recording paper where the sleeve and the recording paper are closest.
The image density in this area will be higher than in other areas, resulting in uneven image density on the resulting recording paper, which is undesirable. Furthermore, if the above-mentioned portion is a non-image portion, toner will adhere to this portion, causing so-called background staining. The present invention provides a developing method that does not cause uneven development or background staining even when an electrostatic latent image carrier is moved intermittently, and a method that is suitable for carrying out the method and that reduces the gap between the electrostatic latent image carrier and the developing roller. An object of the present invention is to provide a developing device that can be easily adjusted.

It is an object of the present invention to move the electrostatic latent image carrier guided by the carrier guide means while being in contact with the fixed sleeve surface, and to move the electrostatic latent image carrier guided by the carrier guide means to the sleeve surface in the same direction as the moving direction of the carrier. The one-component developer is moved along the first wedge-shaped space located upstream in the direction of movement of the carrier among a pair of wedge-shaped spaces formed by the sleeve and the carrier. A developing method and an apparatus for carrying out this method, characterized in that a developer is fed in, and while the developer is held in the space, the developer is supplied to the carrier to develop an electrostatic latent image. , a developer container for storing a one-component developer, a fixed sleeve, and a sleeve provided within the sleeve, the one-component developer in the developer container being moved in the same direction as the moving direction of the electrostatic latent image carrier. a developing roller consisting of a magnet roller that rotates in a direction to move the leaf surface; a first guide member disposed on the upstream side in the moving direction of the carrier; and a second guide disposed on the downstream side in the direction of movement of the carrier. a carrier guide means for guiding the carrier to bring the carrier guided between the two members into contact with the sleeve so as to form a wedge-shaped cross-sectional space therebetween; The developer is disposed in a first wedge-shaped space located on the upstream side in the moving direction of the carrier among a set of wedge-shaped spaces in cross section formed by the developer, and is fed into the first wedge-shaped space by the developing roller. This is achieved by a developing device characterized by comprising a developer holding means for filling the space with the developer while holding the developer.

According to the developing method of the present invention, the developing roller and the electrostatic latent image carrier are brought into contact with each other by the carrier guide means, and a space having a wedge-shaped cross section is formed between the two, and a one-component image carrier is formed in the space. Since the developer is fed into the carrier and is held by the developer holding means, it is supplied to the carrier, so even if the carrier is moved intermittently, the developer may not be present in a part of the carrier when it is stopped. Because it does not adhere to multiple layers, uneven development is eliminated.

In addition, in another wedge-shaped cross-sectional space formed by the carrier and the developing roller, where the contact between the carrier and the developing roller is released, the electrostatic latent image does not adhere to the part of the carrier other than the latent image. Since the developing roller removes and cleans the developer present, recording paper without background stains can be obtained. Also,
According to the developing device of the present invention that implements the above method, since the carrier is stretched over the carrier guide means and brought into contact with the developing roller, the distance between the carrier guide means and the developer roller is adjustment becomes extremely easy.

Furthermore, by bringing the carrier into contact with the developing roller,
Wedge-shaped spaces are formed on the upstream and downstream sides of the contact area between the two in the moving direction of the carrier, and in the first wedge-shaped space on the upstream side, developer is supplied to the carrier to form an electrostatic latent image. Since development is performed and unnecessary developer adhered to the carrier is taken into the second wedge-shaped space on the downstream side to the developing roller side, there is no need to provide a special leaning device.

Hereinafter, the present invention will be explained in detail with reference to the drawings. In FIG. 2, the reference numeral 10 indicates a developing roller, and the reference numeral 11 indicates a carrier guide means. The developing roller 10 is made of a non-magnetic material and includes a sleeve 12 fixed so as not to rotate, and a magnet roller 13 provided inside the sleeve 12. The magnet roller 13 has north and south poles arranged alternately in its circumferential direction, and is rotated clockwise by a drive mechanism (not shown). Below the developing roller 10,
A toner container 14 serving as a developer container containing a one-component developer (hereinafter simply referred to as "toner") is provided.

This toner is moved counterclockwise on the surface of the sleeve 12 when the magnet roller 13 rotates clockwise. This magnet roller 1 is continuously rotated irrespective of the intermittent feeding of recording paper, which will be described later. on the other hand,
The carrier guiding means 11 guides the recording paper 15, which serves as an electrostatic latent image carrier, on which an electrostatic latent image is formed and is moved in the direction of the arrow by a conveying means (not shown) to the sleeve 12.
In this embodiment, it is brought into contact with the peripheral surface of the
It consists of a first roller 16 as a first guide member and a second roller 17 as a second guide member.

Both rollers 16 and 17 are each made of a conductive material and are rotatably provided. The first and second rollers 16 and 17 are arranged in a positional relationship with the developing roller 10 such that the recording paper 15a stretched between these rollers contacts a part of the circumferential surface of the sleeve 12. are arranged with respect to each other.

Therefore, between the recording paper 15a and the sleeve 12, with the contact portion 18 between the two as a boundary, in the moving direction of the recording paper 15, there is a first wedge-shaped space A having a wedge-shaped cross section on the upstream side, and a first wedge-shaped space A having a wedge-shaped cross section on the downstream side. Two wedge-shaped spaces B are formed.

Below the space A, one side edge 19a is connected to the sleeve 1.
A doctor plate 19 as a developer holding means is disposed close to 2 with a gap G therebetween.

In this embodiment, the recording paper 15 is used in a receiving section of a facsimile machine, and is intermittently moved while an electrostatic latent image is formed on it by an electrostatic latent image forming means (not shown).

The operation of the developing device configured as above will be explained.

As shown in FIG. 3, when the magnet roller 13 rotates clockwise, the toner T in the toner container 14 moves counterclockwise on the surface of the sleeve 12 and is sent into the space A through the gap G. It will be done.

Since the sleeve 12 and the recording paper 15a are in contact with each other, the toner sent into the space A is transferred to the magnetic roller 13.
Only a small amount can pass through the contact portion 18 by the action of , and it gradually accumulates in the space A and comes into contact with the recording paper. Toner is continuously fed into the space A as the magnet roller 13 rotates. However, since the capacity of the space A is substantially constant, excess toner falls from the end of the doctor plate 19 into the toner container 14 and is collected. When the toner contacts the recording paper in space A, the electrostatic latent image is developed. That is, the recording paper that stops or passes through the space A always comes into contact with the toner.
Therefore, the recording paper that has moved into space A has its electrostatic latent image developed, and then either stops at that position or is moved further. Even if the recording paper that has been developed moves while contacting the sleeve 12, the toner at this time is electrostatically attracted to the recording paper, so the formed toner image will not be disturbed. It passes through the contact portion 18 without any problems.

In addition to the toner adsorbed to the electrostatic latent image, a small amount of toner passes through the contact portion 18 as the recording paper moves. The toner other than the image that passes through the contact portion 18 includes toner that moves due to friction caused by contact between the recording paper and the sleeve, and toner that is mechanically adhered to the recording paper due to contact between the two. If such toner is fixed while adhering to areas other than the image on the recording paper, it will cause background stains. but,
In the present invention, since the recording paper and the sleeve are in contact with each other, the recording paper downstream of the contact portion 18 gradually moves away from the sleeve in the direction of movement of the recording paper, and at the point when these two separate, the recording paper is in contact with the sleeve. The toner adhering to the background portion is attracted to the sleeve surface and removed by the action of the magnet roller 13.

That is, in the present invention, the developing action is performed in one wedge-shaped cross-sectional space A, and the cleaning action is performed in the other wedge-shaped cross-sectional space B.

Next, the recording paper 15 is intermittently fed when forming an electrostatic latent image, and the relationship with the toner in the space A when this is stopped will be explained.

The recording paper stopped in the space A is in contact with the toner, the toner is electrostatically attracted to the electrostatic latent image, and the toner merely contacts the background portion. However, since no external force such as rubbing against the recording paper is applied to the toner in the space A, no more toner than the electric charge attached to the electrostatic latent image is attached to the electrostatic latent image. Therefore, even if the intermittently fed recording paper comes into contact with the toner and stops, the phenomenon of uneven development, in which the image density in this area is higher than in other areas, does not occur. This means that when the recording paper in the apparatus shown in FIG. 1 is stopped, moving toner is repeatedly supplied to the electrostatic latent image, causing more toner than necessary Compared to the phenomenon of adhesion, this is a big difference in effectiveness in the development method.

Furthermore, in the present invention, since the sleeve and the recording paper are brought into contact with each other, it is extremely easy to adjust the gap between the sleeve and the first and second rollers that guide the recording paper, and by forming the wedge-shaped spaces A and B in cross section. This is sufficient, so even if the positions of the two rollers are slightly shifted, the developing and cleaning functions will not be impaired.

In other words, the cost can be kept low because the means for supporting both rollers does not require high precision.
The above is an explanation of an embodiment in which the present invention is applied to a recording section of a facsimile machine, but the present invention is not limited to this, and various embodiments are possible within the scope of the present invention.

Furthermore, the carrier guiding means may be a non-rotating body instead of the first and second rollers, and the outer surface of the sleeve 12 may be coated with a member having a low coefficient of friction to guide the electrostatic latent image carrier. It is more preferable to reduce the friction as much as possible.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing an example of a conventional developing device, FIG. 2 is a front sectional view showing an embodiment of the developing device of the present invention, and FIG. 3 is an operational view of FIG. 2. 10...Developing roller, 11...Carrier guide means, 12...Sleeve, 13...
... Magnet roller 1, 15 ... Recording paper, 1
6...First roller 17...Second roller, 18...Contact portion, A...Wedge-shaped space in cross section.

Claims (1)

[Scope of Claims] 1. The electrostatic latent image carrier guided by the carrier guide means is moved in one direction while being in contact with the fixed sleeve surface, and the electrostatic latent image carrier is moved in the same direction as the moving direction of the carrier. , by moving the one-component developer along the sleeve surface,
The developer is fed into a first wedge-shaped space located on the upstream side in the moving direction of the carrier among a pair of wedge-shaped spaces in cross section formed by the sleeve and the carrier, and the developer is held in the space. A developing method characterized in that the developer is supplied to the carrier to develop the electrostatic latent image. 2. A developer container for storing a one-component developer, a fixed sleeve, and a sleeve provided within the sleeve to move the developer in the developer container in the same direction as the moving direction of the electrostatic latent image carrier. a developing roller consisting of a magnetic roller that rotates in a direction to move it along the sleeve surface;
A first disposed on the upstream side in the moving direction of the carrier.
It is composed of a guide member and a second guide member disposed on the downstream side, and the carrier guided between the two members is brought into contact with the sleeve, and the carrier is guided so that the two members form a wedge-shaped space in cross section. The carrier guide means is disposed in a first wedge-shaped space located on the upstream side in the moving direction of the carrier among a set of wedge-shaped spaces in cross section formed by the sleeve and the carrier, and is arranged in a first wedge-shaped space located on the upstream side in the moving direction of the carrier, and A developing device comprising a developer holding means for holding the developer sent into the first wedge-shaped space and filling the space with the developer. 3. The developer holding means includes a doctor plate having one side edge close to the sleeve and the opposite side edge positioned above the developer container, and is fed into the first wedge-shaped space. 3. The developing device according to claim 2, wherein the surplus developer is collected by flowing down into the developer container from the other side edge.