JPH0223379A - Nonmagnetic single-component developing device - Google Patents

Abstract

PURPOSE:To charge toner powder electrostatically and sufficiently by friction and to form a layer of the toner powder to uniform layer thickness by composing a toner powder thin layer forming means of an endless belt which circulates around conductive elastic rollers and a toner layer thickness control means and forming a nonconductive resin surface layer on the endless belt. CONSTITUTION:The toner powder thin layer forming means consists of the endless belt 33 which circulates around the conductive elastic rollers 31 and 32 and the toner layer thickness controller 36. The endless belt 33 consists of the surface 33a made of a nonmagnetic resin material which contacts and charges supplied toner electrostatically by friction and a base layer 33b made of a metallic sheet. Toner powder 16 which is supplied onto the endless belt 33 from a housing 30 is charged electrostatically by coming into friction contact with the surface layer 33a. This toner powder forms a toner layer by sticking the surface of the belt 33 with a bias potential applied to the endless belt 33 through a conductive elastic roller 31 and a mirror image force generated on the belt and the layer is adjusted to uniform thickness. Consequently, the toner powder is charged on a developing means electrostatically and sufficiently by friction to obtain the uniform layer thickness.

Description

[Detailed Description of the Invention] [Summary] Regarding a developing device used in an electrophotographic apparatus, particularly regarding a new developing device configuration of a type using non-magnetic single-component toner, it is necessary to provide sufficient amount of toner powder on the developing means. The purpose of the present invention is to provide a new developing device that can apply frictional electrification and form a layer with a uniform thickness. Non-magnetic monocomponent toner powder is applied to the surface of a carrier through a toner powder thin layer forming means. supply,
The developing device visualizes the latent image formed on the surface of the carrier and repeatedly cleans and collects the toner powder remaining on the toner powder non-forming means by a collecting means, wherein the toner powder thin layer forming means is , consisting of an endless belt that revolves around a conductive elastic roller, and a toner layer thickness regulating means that adjusts the layer thickness of toner powder on the endless belt, and the endless belt comes into contact with and controls the supplied toner. a surface layer made of a non-conductive resin material that can be triboelectrically charged; and a base layer made of a metal sheet that is in contact with the conductive elastic roller; It is configured so that it rotates while being pressed by.

[Industrial application field]

The present invention relates to a developing device used in an electrophotographic apparatus, and more particularly to a new type of developing device that uses non-magnetic single-component toner.

[Conventional technology]

The electrophotographic apparatus has a configuration as shown in FIG. That is, a charger 2. is placed around the photosensitive drum 1 rotating in the direction of the arrow. Exposure device 3. Developing device 4, transfer device 5. A static eliminating lamp 6 and a cleaner 7 are arranged. First, a positive charge is applied to the entire surface of the photosensitive drum 1 by corona discharge generated from the charger 2. Next, when light corresponding to a predetermined pattern is applied to this surface from the exposure device 3, the charge in the exposed portion is lost and a latent image is formed. When this latent image area passes through the developing device 4, positively charged toner adheres thereto, forming a toner image. On the other hand, the paper 8 on which the image is printed is fed one by one to a position where it comes into contact with the toner image formed on the photosensitive drum 1 by the action of the piff roller 9 and the standby roller 10.

The transfer device 5 is installed below the photosensitive drum 1 with the paper 8 in between, and is configured to apply a negative charge to the paper 8. Therefore, the toner image formed on the surface of the photosensitive drum 10 is attracted to the negative charge of the paper 8 and transferred thereto. The paper 8 carrying the toner image is transferred to a fixing device 11
The toner image is fixed on the paper 8 by heat and pressure. The charge on the surface of the photosensitive drum 1 on which the toner has been transferred to the paper 8 is completely neutralized by the neutralizing lamp 6, and the remaining toner is cleaned by the cleaner 7 to return to the initial state, and the above-described cycle is repeated again.

A conventionally used developing device 4 is as shown in FIG. 5, in which a sponge roller 15 pressed against the surface of the photosensitive drum 1 is installed in a container 18 containing powdered toner 16. There is.

The toner 16 being agitated by the agitator 19 is
When the toner is rubbed onto the surface of the developing roller 14 via the toner supply roller 15 made of a soft sponge or fur brush, the toner adheres to the surface of the developing roller 14 in a positively charged state as a thin layer. This toner layer is further charged by being rubbed by the blade 20 and at the same time adjusted to have a uniform thickness. The image is then transferred onto the surface of the photosensitive drum 10 as the developing roller 14 rotates.

In order to facilitate the transfer of toner between the rollers, the rollers are configured to have different potentials between the rollers.

[Problem to be solved by the invention]

In such conventional developing devices, it is difficult to sufficiently triboelectrically charge the toner powder on the developing roller, and it is also difficult to control the layer thickness uniformly using a blade.

The present invention solves the problems of the prior art and provides a new developing device that can apply sufficient triboelectric charge to toner powder on a developing means and form a uniform layer thickness. With the goal.

[Means to solve the problem]

The purpose of this is, for example, as shown in FIG. 1, to visualize the latent image formed on the surface of the carrier by supplying non-magnetic mono-component toner powder to the surface of the carrier through a toner powder thin layer forming means. , a developing device for an electrophotographic apparatus in which toner powder remaining on the toner thin layer forming means is repeatedly cleaned and collected by a collecting means, wherein the toner powder thin layer forming means includes conductive elastic rollers 31 and 32; an endless belt 33 that circulates around the endless belt 33; a toner supply device such as a housing 30 that supplies toner powder onto the endless belt 33; and a toner layer thickness such as a blade 16 that adjusts the layer thickness of the toner powder on the endless belt 33. The endless belt 33 is in contact with a surface layer 33a made of a non-conductive resin material capable of triboelectrically charging the supplied toner by contacting it, and the conductive elastic roller 31.32. This is achieved by a developing device which is composed of a base layer 33b made of a metal sheet, and which rotates while being pressed against the carrier surface 1 with a predetermined pressure by the conductive elastic roller 31.

[For production]

The toner powder 16 supplied onto the endless belt 33 running from the housing 30 is charged by frictional contact with the surface layer 33a. The charged toner powder adheres to the surface of the belt 33 to form a toner layer due to the bias potential applied to the endless belt 33 through the conductive elastic roller 31 and the mirror image force generated in the belt. belt 33
The thickness is adjusted to be uniform by contacting the substrate 1, and the substrate is conveyed to the surface of the carrier 1. Since there is a potential difference between the belt and the carrier surface, the toner powder is transferred to the electrostatic latent image area on the carrier surface, making it visible.

The toner powder remaining on the endless belt 33 is collected into the housing 30 by a collecting device 38, which will be described later, and the belt 33 returns to its initial state and the above-described cycle is repeated again.

Hereinafter, the present invention will be explained in more detail based on preferred embodiments shown in the drawings.

〔Example〕

FIG. 1 is a side view showing the structure of a first embodiment of a developing device according to the present invention, which is used in place of the developing device 4 in FIG. 5 described above.

This developing device is housed in a housing 30 that covers the entire body, and includes an endless belt 33 wrapped around a pair of rollers 31 and 32 that are rotated in the direction of the arrow by a driving means (not shown). The housing 30 has an opening 34 on one side of the roller 31, and in this area, the belt 33 is pressed by the roller 31 and comes into contact with the surface of the photosensitive drum 10, which is a latent image carrier, with a predetermined pressure.

The belt 33 has a two-layer cross section as shown in FIG. 2, and its surface layer 33a is made of a material that can charge the toner powder through frictional contact, such as polyester, acrylic, styrene, or acrylic. - It is made of a resin such as urethane, epoxy-silicon, or epoxy-Teflon, and the base layer 33b is made of a sheet of conductive metal such as aluminum. The roller 31 that presses the belt 33 against the photosensitive drum 1 is made of a material that has both conductivity and elasticity, such as carbon-containing nitrile butadiene rubber. This causes the belt 33 to move to the roller 32.
When the base layer 33b and the roller 31 are wrapped around the roller 31, the base layer 33b and the roller 31 can be electrically connected. Further, a bias potential higher than that of the photosensitive drum 1 is applied to the roller 31 .

A part of the housing 30 constitutes a toner storage chamber 35, in which powdered toner 16 is stored so as to be in contact with the upper surface of the belt 33.

Further, a toner layer thickness regulating blade 36 is installed on the upper surface of the belt 33 in front of the storage chamber 35 with respect to the traveling direction. This blade 36 is made of silicone rubber or the like, and a spring 37 applies a predetermined pressure to the tip of the blade 36 so that it is attached to the belt 33.
is in contact with the top surface of the Furthermore, a collection blade 38 is provided at the rear of the storage chamber 35. In the figure, reference numeral 39 is a guide plate that cooperates with both blades 36 and 38, and 29 is an agitator that stirs the toner.

Next, the operation of the above configuration will be explained.

As the belt 33 moves in the direction shown, the toner 16 within the storage chamber 35 is charged by frictional contact with the surface of the belt 33. The charged toner powder adheres to the surface of the belt 33 due to the mirror image force generated on the belt 33 and the bias potential applied to the belt through the roller 31, and the progress of the tongue 33 is caused by the charged toner powder. At the same time, it is carried out from the storage chamber 35. Then, by the action of the layer thickness regulating blade 36, the toner powder with a small amount of charge is stripped off, and only the powder with a charge amount of a predetermined value or more is leveled to have a uniform thickness, and the belt 33 comes into contact with the surface of the photosensitive drum 10. The image is transported to the developing area. Here, the toner layer on the belt 33 is transferred onto the electrostatic latent image formed on the surface of the photosensitive drum, making it visible.

The toner powder remaining on the belt 33 is collected by the collection blade 3
8, it is peeled off from the belt surface and returns to the collection chamber 35 again. By repeating this cycle, continuous output is possible.

Another embodiment of the invention is shown in FIG. 3, according to which the 1r! In place of the collecting blade 38 in the example A, a collecting roller 40 that rotates in the direction shown is employed.

This makes it possible to more reliably collect the toner powder.

〔Effect of the invention〕

As detailed above, according to the present invention, a developing device consisting of a pair of rollers and an endless belt wound around the rollers is used instead of the conventional developing roller, so that a sufficient amount of charge is applied to the toner powder. In addition, the layer thickness can be made more uniform. This made it possible to develop with better quality.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the structure of a developing device according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view showing the structure of a belt used therein, and FIG. 3 is a side view of the second embodiment. 4 is a side view showing the overall structure of an electrophotographic apparatus to which the present invention is applied, and FIG. 5 is a side view schematically showing the structure of a conventional developing device. ■ Photosensitive drum, 30 housing, 31.
32 roller, 33 belt, 33a belt surface layer, 33b belt base layer, 34 opening,
35 Containment chamber, 36 Layer thickness regulation blade, 37
Spring, 38 collection blade, 40 collection roller.

Claims (1)

[Claims] 1. A non-magnetic mono-component toner powder is supplied to the surface of the carrier through a toner powder thin layer forming means, and the latent image formed on the carrier surface is visualized to remain on the toner thin layer forming means. The developing device repeatedly cleans and collects the toner powder by a collecting means, and the toner powder thin layer forming means includes an endless belt (33) that revolves around conductive elastic rollers (31, 32), The endless belt includes a toner supply device (30) that supplies toner powder (16) onto the endless belt (33), and a toner layer thickness regulating device (36) that adjusts the layer thickness of the toner powder on the endless belt. (33
) is made of a surface layer (33a) made of a non-conductive material capable of triboelectrically charging the supplied toner and a metal sheet in contact with said conductive elastic rollers (31, 32). A developing device comprising a base layer (33b) and rotating while being pressed against the carrier surface (1) with a predetermined pressure by the conductive elastic roller (31).