JPH01237676A - Developing device - Google Patents

Abstract

PURPOSE:To miniaturize the whole device by using a toner carrying member which has been extended to at least a pair of guide rollers. CONSTITUTION:The first guide roller 2 is placed in the vicinity of an electrostatic image holding means 7, the second guide roller 1 is placed in parallel to said roller, and also, at an interval, a toner carrying member 3 is extended to the guide rollers 1, 2 and also, toner thin layer forming means 5, 9 for forming a toner thin layer are provided on the surface of the toner carrying member 3 on the second guide roller 1. In such a way, when this device has been applied to a multicolor developing device, a developing device fixing system can be used, and the space can be utilized effectively, therefore, even if a photosensitive drum whose outside diameter is large is not used, four sets of developing devices of each color can be installed.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (Field of Industrial Application) The present invention relates to a developing device using a non-magnetic component toner in an electrophotographic or electrostatic recording device.

(Prior Art) In the non-magnetic component development system, a developing device as shown in FIG. 4 is widely used.

In this developing device, a developing roll 42 rotatable in the direction of the arrow is arranged in the opening of a toner container 41 having an opening at the bottom, an elastic blade 43 is pressed against the upper part of the developing roll 42, and a collecting blade 44 is placed in the lower part. At the same time, the developing roll 42 is pressed against the photoreceptor drum 45 to close the opening.
It is placed close to. 46 is a developing roll 42
This is a bias electrode that applies a bias voltage to the

In this developing device, the toner 47 in the toner container 41 is
The developing roll 4 is formed by the elastic blade 43 and the intermediate roll 48.
2, and the toner particles are given a charge of opposite polarity to the electrostatic image charge by friction between the developing roll 42, the elastic blade 43, and the toner 47. When the toner applied to the surface of the developing roll 42 approaches the photosensitive drum 45, it is transferred to the photosensitive drum 45 and transferred onto the transfer paper, and the toner remaining on the developing roll 42 is transferred to the photosensitive drum 45.
The toner is collected into the toner container 41 from between the collection blade 44 and the developing roll 42 . 4 is a stirrer for stirring the toner.

Incidentally, when such a developing device is used for multicolor copying of three to four colors, a configuration as shown in FIG. 5 or 6 is generally adopted.

In the multicolor copying apparatus shown in FIG.
51c is each developing roll 53a around the photoreceptor drum 52.
~53c are arranged side by side.

In this copying apparatus, first, the photosensitive drum 52 is connected to the charger 54.
, and is exposed by an exposure optical system from the direction of arrow B to form an electrostatic image on the photosensitive drum 52. For example, a first color toner image is developed by the first developing device 51a. This toner image is transferred onto a transfer paper held on a transfer roll 55 disposed close to the photoreceptor drum 52, and the toner remaining on the photoreceptor drum 52 is collected by a toner collector 56.

Subsequently, the second developing device 51b and the third developing device 5
Using 1C, toner images of other colors are multiple-transferred onto the transfer paper on the transfer roll 55 in a similar manner.

In the multicolor copying apparatus shown in FIG.
A rotary type in which 61c is fixed radially around a rotating shaft is used. In this multicolor copying apparatus, first, one of the developing devices, for example, the developing device 61a, is exposed to light from the direction of arrow B with the developing device 61a facing the photosensitive drum 62, and then the first color is developed by the developing roll 63a. The toner image of the lever is transferred onto a transfer paper held on a transfer roll 64.

Next, the developing device 61b is directed toward the photoreceptor drum 62,
Similarly, the second color is developed and transferred, and the third color is developed and transferred with the developing device 61c facing the photosensitive drum 62 side.

In the figure, 65 is a charger, and 66 is a toner collector.

In addition to the apparatuses shown in FIGS. 5 and 6, there are also known systems in which a photoconductor drum is used for each color and a system in which a belt-type photoconductor is used, depending on the arrangement of the photoconductors. .

(Problems to be Solved by the Invention) However, these conventional developing devices have the following problems.

That is, in the developing device for multicolor copying shown in Fig. 5, the developing device is arranged around the photosensitive drum, so the diameter of the photosensitive drum must be increased due to space issues. Yes, the entire device becomes larger.

- The developing position relative to the drum is different for each color, which imposes restrictions on the configuration of the developing device for each color.

■ It is impossible to standardize the developing device for each color, and a dedicated developing device must be designed and manufactured for each color.

In addition, the developing device 1 shown in FIG. 6 has a structure in which (1) a plurality of developing devices are moved rotationally or linearly to perform development at a fixed position on the photosensitive drum; becomes complex and large.

Furthermore, depending on the arrangement of the photosensitive drums, in an apparatus using a photosensitive drum for each color, (1) the image forming system requires units for three to four colors;

■ Because the development positions for each color are far apart, alignment for multiple transfers is difficult and color misalignment is likely to occur.

Furthermore, in a developing device that uses a belt-type photoreceptor, (1) It is difficult to align the positions of multiple transfers, and color misregistration is likely to occur.

It had the following drawback.

(Problems to be Solved by the Invention) As described above, the conventional developing device has many problems, especially when it is used for multicolor development.

The present invention was made to solve these problems.
It is an object of the present invention to provide a developing device that does not have the above-mentioned drawbacks by using a toner conveying member wrapped around at least a pair of guide rolls in place of the conventional developing roll.

[Structure of the Invention] (Means for Solving the Problems) That is, the developing device of the present invention includes a first guide roll disposed close to the electrostatic image holding means, and a first guide roll arranged in parallel with the first guide roll. and a toner transporting member that is stretched over these guide rolls, and a toner thin layer that forms a toner thin layer on the surface of the toner transporting member on the second guide roll. It is characterized by having a layer forming means.

The material of the guide roll used in the present invention may be metal or a shaft material made of stainless steel coated with silicone rubber, urethane rubber/foam, or the like.

The roll materials used in the same developing device are not limited to those having the same material and the same structure, but materials and structures suitable for each portion can be used as appropriate.

An endless belt is usually used as the toner conveying member used in the present invention.

As this endless belt, for example, a conductive and flexible film or sheet formed into a belt shape, such as an aluminum foil, a conductive polyester sheet, or a conductive polyethylene sheet, is used, and preferably a belt shape is used. It is best to have no seams.

Further, the electrostatic image holder and the toner image conveying member, which is stretched around a guide roll disposed close to the electrostatic image holder, may be arranged with a small interval between them, but the above-mentioned guide When an elastic material is used as the constituent material of the roll, it is also possible to develop the image by bringing the surface of the electrostatic image holder into contact with the toner image conveying member on which a thin toner layer is formed, which is stretched around this guide roll. be.

Further, in the developing device of the present invention, the plurality of sets are arranged such that the developing roll at the tip thereof is close to or in contact with a common electrostatic latent image holding means, and the developing device formed on the electrostatic latent image holding means is By arranging transfer members for multiple transfer of toner images, a multicolor electrophotographic device or a multicolor copying device can be configured.

(Function) In the developing device of the present invention, a thin layer of toner is formed on the surface of the toner conveying member stretched over the guide roll on the toner container side. This thin layer of toner is conveyed by a toner transport member to the other guide roll where it is transferred onto an electrostatic image bearing means disposed in close proximity to the guide roll to develop the electrostatic image. This electrostatic image is then transferred onto a toner image holding means.

In the case of multicolor development, a plurality of developing devices each containing toners of different colors in toner containers sequentially perform development with toners of each color on a common electrostatic image holder. These toner images are normally multiple-transferred in order onto transfer paper held on a common transfer roll.

By the way, when a conventional developing device is applied to multicolor development,
Even if the diameter of each developing roll is made smaller, the number of developing devices that can be placed around a photoreceptor drum with a diameter of 60 m is limited to two, so it is recommended to increase the number of developing devices by reducing the diameter of the developing roll. In this case, frictional charging between the developing roll, the elastic sleeve, and the toner becomes insufficient, and only an unstable charge can be applied, resulting in problems such as problems occurring in subsequent processes. In contrast, in the present invention, even if the guide roll on the electrostatic image holding means side is made small in diameter, the guide roll on the toner container side does not need to be made small in diameter.
It is possible to arrange many developing devices in close proximity to the photoreceptor roll, which is the electrostatic latent holding means, without causing problems such as insufficient triboelectric charging.

Furthermore, if the guide rolls on the electrostatic image holder side are made small in diameter, the developing belt stretched between the guide rolls will have a wedge shape with a pointed tip, so three or four developing devices will be attached to the photoreceptor. When placed around an electrostatic image carrier such as a drum,
Space can be taken up effectively, and there is no need to use developing devices for each color that have different shapes depending on the placement position, and it becomes possible to share the developing device for each color. Furthermore, by reducing the diameter of the guide roll on the electrostatic image holder side, the force that acts on the toner from the surface of the electrostatic image holder is prevented from acting on the surrounding area, and the toner is scattered toward the electrostatic image holder side. This phenomenon can be suppressed.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view schematically showing the configuration of an embodiment of the present invention.

In this embodiment, a toner thin layer forming roll 1 and a photosensitive drum proximity roll 2 having a smaller diameter are arranged in parallel with an interval, and a developing belt 3 is stretched between these rolls 1.2.

The toner thin layer forming roll 1 is disposed in the opening of a toner container 4 having an opening at the lower part, and an elastic blade 5 fixed to the toner container 4 is attached to the upper part of the toner thin layer forming roll 1.
The toner collection blade 6 is pressed at a pressure of 0 g/Cl1l, and the toner collection blade 6 is also pressed at the lower part of the toner thin layer forming roll 1 at approximately the same pressure.

The photosensitive drum 7 has, for example, a selenium-based photoconductor layer on its surface, and is arranged close to and parallel to the photosensitive drum proximity roll 2 .

The toner 8 in the toner container 4 is applied extremely thinly to the surface of the developing belt 3 by an intermediate roll 9 and an elastic blade 5 disposed close to the developing belt 3, and the toner particles are
Friction between the developing belt 3, the elastic blade 5, and the toner itself provides a charge having a polarity opposite to that of the electrostatic image charge.

The toner 8 applied to the surface of the developing belt 3 is conveyed to the photoreceptor drum 7 side, and when it approaches the photoreceptor drum 7 on the photoreceptor drum proximity roll 2, it is transferred onto the photoreceptor drum 7 and is developed. The toner remaining on the belt 3 is collected by the collection blade 6.
and the developing belt 30 and are collected into the toner container 4.

10 is a stirrer for stirring the toner.

At this time, between the developing belt 3 and the surface of the photoreceptor drum 6,
A direct current bias, an alternating current bias, or a bias in which direct current and alternating current are superimposed may be applied from the bias power supply 11.

FIG. 2 shows another embodiment of the invention. In the following embodiments, parts common to those in the embodiment of FIG. 1 are denoted by the same reference numerals, and redundant explanations will be omitted.

This developing device uses two toner thin layer forming rolls on the side of the toner container 4 shown in FIG. 3 and the intermediate roll 9 are configured to be brought into contact between these toner thin layer forming rolls 1'.

In this embodiment, sufficient contact between the intermediate roll 9 and the developing belt 3 is achieved, so that the uniformity of the toner thin layer on the developing belt 3 and the application of electrical charge can be increased within the layer. .

FIG. 3 shows an example in which the embodiment shown in FIG. 1 is applied to a multicolor copying device, and the developing device shown in FIG. 1 stores toners of different colors.

12a to 12d have a configuration in which the photosensitive drum proximity roll 2 is disposed close to the photosensitive drum 7.

In this embodiment, the photoreceptor drum 7 is uniformly charged by the charger 13, exposed to light by the exposure optical system from the direction of arrow B, and then subjected to first development by the developing device 12a and then to the first color image. A colored toner image is formed. This toner image is transferred onto a transfer paper supported on a transfer drum 14. Next, the toner remaining on the photoreceptor drum 7 is collected by the toner collector 15, the surface charge of the photoreceptor drum 7 is removed by the static eliminator 16, and a second color is developed in the same manner using the developing device 12b. Development and transfer using toner are performed. By repeating this process, toner images of different colors are multiple-transferred onto the transfer paper to form a color image.

In this example, when a photoreceptor drum with a diameter of 60 m is used, a 30% reduction in device size is achieved compared to a multicolor copying device of the same capacity using a conventional developing device moving system. It was done. In this example, since the developing device is fixed, there is no need for a complicated moving mechanism.
% improvement in transfer speed was achieved. Furthermore, in this embodiment, a developing device of the same design can be used for each color, resulting in labor savings in design and manufacturing.

In this example, the developing roll shown in FIG. 1 was used, but as shown in FIG. It is also possible to add one or more rolls between the guide rolls on the image holder side.

[Effects of the Invention] As explained above, the present invention has a method in which a first guide roll is disposed close to the electrostatic image holding means, and a second guide roll is disposed parallel to the first guide roll at a distance therefrom. The toner conveying member is stretched around these guide rolls, and a toner thin layer forming means is provided for forming a thin toner layer on the surface of the toner conveying member on the second guide roll. Various effects can be obtained.

(a) When the developing device of the present invention is applied to a multicolor developing device, it is possible to use a fixed developing device method, and a complicated moving mechanism for the developing device is not required.

(b) Since space can be used effectively, four developing devices for each color can be installed without using a photosensitive drum with a large outer diameter.

(c) Since the diameter of the roll close to the photoreceptor drum can be minimized, it is possible to suppress deviation of the development position with respect to the photoreceptor drum.

(d) Since one type of developing device can be used for each color, there is no need to design and manufacture a dedicated developing device for each color.

(e) The entire copying apparatus can be downsized.

(f) Even if the developing device is placed below the photoconductor drum and toner is supplied from the bottom to the top, the developing device can be smoothly supplied without having to provide a complicated mechanism such as toner feeding. Toner is transported.

[Brief explanation of the drawing]

1 to 3 are diagrams each schematically showing an embodiment of the developing device of the present invention, and FIGS. 4 to 6 are diagrams showing a conventional developing device. 1.1'... Toner thin layer forming roll 2... Photosensitive drum proximity roll 3...
......Development belt 4...Toner container 5...Elastic blade 6...Toner collection blade 7...・
...Photoconductor drum 8...Toner 11...Bias power supply Applicant Toshiba Corporation Representative Patent attorney Sasu Suyama - Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] (1) A first guide roll disposed close to the electrostatic image holding means, a second guide roll disposed parallel to the first guide roll at a distance, and a A developing device comprising: a passed toner conveying member; and toner thin layer forming means for forming a thin toner layer on the surface of the toner conveying member on a second guide roll.