JPS6355066B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing device for developing an electrostatic latent image formed on the surface of a photoreceptor of an electronic copying machine.

One of the developing devices for electronic copying machines currently in practical use is one that uses a magnetic brush. This uses a magnetic two-component or magnetic one-component method in which a magnetic brush is brought into sliding contact with a photoreceptor, which is an image carrier, and supplies toner or magnetic toner to an electrostatic latent image formed on the surface of the photoreceptor. There is.

However, the magnetic roller that forms the magnetic brush is expensive and requires a high degree of mechanical precision, and in the magnetic two-component method, the carrier itself has a limited lifespan, making it difficult to maintain a constant mixing ratio of the carrier and toner. There are drawbacks such as difficulty in maintaining the stability of the machine, and a lot of time and effort is required to maintain the stability of the machine.

Furthermore, recently, a fur brush development method using a fur brush roller has been proposed, but since the developer used here is a non-magnetic toner that does not use a carrier, the toner is uniformly charged and background fog in the image is prevented. It is necessary to do so. However, conventionally, a bias voltage is applied to the fur brush roller to charge the toner, but there is variation in the amount of toner charge, and background fogging of images due to uncharged toner is unavoidable.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to increase the amount of toner supplied and the amount of toner charge by making the surface of the toner supplying member that rubs against the rotating body a satin finish. The object of the present invention is to provide a developing device that can prevent background fog in images and obtain stable copied images.

Hereinafter, one embodiment of the developing device according to the present invention will be described in detail with reference to FIGS. 1 to 3 of the accompanying drawings.

FIG. 1 shows the basic configuration of an electronic copying machine, where 1 is the main body. A document mounting table 2 is provided on the upper surface of the main body 1, and is configured to reciprocate by a drive motor 3 provided within the main body 1. A photoreceptor 4 serving as an image carrier that rotates in synchronization with the movement of the mounting table 2 is pivotally supported approximately at the center of the main body 1 . This photoreceptor 4 has a cylindrical base, is provided on the outer peripheral surface of this base, and is made of zinc oxide.
Made of resin dispersant. An exposure system 7 consisting of a lamp 5, a convergent light transmitter 6, etc. is provided between the photoreceptor 4 and the original platen 2, and illuminates the original on the original platen 2, and directs the reflected light to the photoreceptor. It is adapted to be guided to layer 4 to form an image of the document. An image forming device 8, a transfer device 9, a cleaning device 10, and a charging device 11, which will be described later, are arranged in this order along the clockwise rotation direction of the exposure body 4 from this image forming position. The developing device 8 visualizes the latent image of the document formed on the photoreceptor layer 4 by the exposure system 7. The transfer device 9 is for transferring the original toner image formed on the photoconductor 4 onto the copy paper p, and the cleaning device 10 is for removing toner remaining on the surface of the photoconductor layer 4. Further, at the bottom of the main body 1, there is provided a paper feeding device 14 consisting of a removable cassette 12 for storing copy paper p, and a paper feed roller 13 for detecting the copy paper p. Further, the transfer device 9 includes a transfer belt 17 having an insulating property such as Mylar (trade name), which is stretched between a transfer roller 15 and a plurality of guide rollers 16, 16. The transfer belt 17 is in contact with a part of the outer circumferential surface of the photoreceptor 4, and the transfer belt 17 has a transfer charging device 1 which basically has the same structure as the charging device 11.
8 and cleaning blade 19 are in contact with each other. Further, a fixing device 20 and a delivery roller 21 are provided on the delivery end side of the transfer belt 17.
The copy paper p onto which the image has been transferred by the transfer device 9 is fixed, and then transported to the tray 22. Note that 23 is a control device.

The motor 3 is a motor equipped with a non-air fan, and is designed to exhaust heat generated in the exposure system 7 as the motor rotates to the outside of the main body 1. The photoreceptor 4 is a basic thin-walled aluminum drum with a thickness of 0.8 mm and a diameter of about 80 mm.The outer peripheral surface of the photoreceptor 4 is made of a binder type of zinc oxide-resin dispersant sensitized with a dye such as rose bengal. The body 4 is formed by coating. Further, the cleaning blade 19 described above is used to clean the transfer belt 17 by scraping off toner and the like adhering to the transfer belt 17.

Next, the developing device 8 will be explained based on FIG. It is formed by flocking bristles 28 through a conductive adhesive layer 27, and the bristles 28 come into sliding contact with the surface of the photoreceptor 4. Furthermore, the hair body 28 has a length of 0.5 to 1.5 mm and a thickness of 1.5 to 1.5 mm.
Made of 7.0 denier rayon, acrylic, and nylon fibers. Further, a toner supply member such as a toner supply roller 29 is installed adjacent to and parallel to the developing fur brush roller 24 .

This toner supply roller 29 is a cylindrical body made of a metal material, and the surface is processed to have a satin finish, and the surface is further coated with Teflon. Further, a blade 30 is provided in contact with this toner supply roller 29 . Further, the developing fur brush roller 24 is provided with a metal toner collecting roller 3 that comes into sliding contact with the bristles 28 of the developing fur brush roller 24 and collects undeveloped toner.
1 is installed in contact with the blade 32, and these rollers 24, 29, 31 are adapted to rotate in the directions of the arrows. Reference numeral 33 denotes a toner supply box containing the non-magnetic toner 34. A stirring blade 35 for stirring the non-magnetic toner 34 is provided inside this box, and a fur brush roller 29 for supplying the toner is attached to the lower part of the toner supply box 33 for storing the non-magnetic toner 34. A toner supply port 36 for supplying toner is provided. Further, a casing 37 is provided continuously from the toner supply port 36 and integrally with the toner supply box 33, and surrounds the development fur brush roller 24, the toner supply roller 29, and the toner recovery roller 31. The inner surface of the casing 37 is embossed 38 as shown in FIG. 3 to improve frictional charging. Note that 39 is a bias power source for applying a bias voltage to the developing fur brush roller 24.

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

When the electrostatic latent image formed on the surface of the photoreceptor 4 faces the developing device 8 as the photoreceptor 4 rotates, the developing fur brush roller 24 rotating in the direction of the arrow causes the electrostatic latent image to be formed on the surface of the photoreceptor 4. Magnetic toner 34 is supplied and the electrostatic latent image is developed. That is, the non-magnetic toner 34 in the toner supply box 33 is conveyed between the toner supply port 36 and the casing 37 by the toner supply roller 29, and is supplied to the developing fur brush roller 24. At this time, the surface of the toner supply roller 29 is given a pear finish finish and is provided with a Teflon coating layer.
In addition, since the non-magnetic toner 34 rubs against the bristles 28 of the developing fur brush roller 24, the non-magnetic toner 34 is triboelectrically charged. The non-magnetic toner 34 triboelectrically charged in this manner is supplied to the surface of the photoreceptor 4 as the developing fur brush roller 24 rotates, and the electrostatic latent image formed on the surface of the photoreceptor 4 is developed. It turns out. Note that the undeveloped toner remaining on the developing fur brush roller 24 adheres to the surface of the toner collection roller 31 and is then scraped off by the blade 32.

As described above, the present invention is characterized in that the surface of the toner supply member that rubs against the rotating body is made of a satin finish. Therefore, the toner supply amount and
The amount of toner charge increases, and it is possible to prevent background fog on images due to uncharged toner. Moreover, by forming the surface of the toner supply roller with a satin finish, frictional charging with the bristles can be performed satisfactorily and stably.

[Brief explanation of the drawing]

The drawings show one embodiment of the invention.
2 is a schematic configuration diagram of the electronic copying machine, FIG. 2 is a longitudinal sectional front view of the developing device, and FIG. 3 is a plan view showing the inner surface of the casing. 4... Photoreceptor (image carrier), 24... Fur brush roller for development (rotating body), 28... Hair body, 2
9... Toner supply roller (toner supply member),
37...Casing.

Claims (1)

[Scope of Claims] 1. A device that supplies toner to an electrostatic latent image formed on the surface of an image carrier and develops the electrostatic latent image, wherein a hair body that rubs against the surface of the image carrier is provided. 1. A developing device comprising: a rotating body; a toner supply member having a satin-like surface that rubs against the rotating body; and a casing surrounding the rotary body and the toner supply member. 2. The developing device according to claim 1, wherein the inner surface of the casing is embossed.