JPS62211681A - Developing and cleaning device - Google Patents

Abstract

PURPOSE:To maintain a good developing property, and to improve the cleaning property of a photosensitive body by installing a bias power source for switching mutually a developing bias voltage which has been set somewhat low, and a cleaning bias voltage which has been set a little higher than said voltage. CONSTITUTION:A corona destaticizer and electrifier 2, an exposure optical system 3, a developing and cleaning device 4, a transfer corona discharge device 5 and an erasion exposure device 6, etc., are placed in the periphery of a photosensitive drum 1. An original image is projected by the optical system 3 onto the surface charge of the drum is dissipated in the irradiated area, and an electrostatic latent image is formed. This electrostatic latent image is converted to a visible image by the device 4. A rotary member 7 of this device 4 is provided adjacently to the drum 1, and a bias power source 8 is connected to the member 7. Also, on the power source 8, a DC power source 10 and an AC power source 11 are provided in parallel through a changeover switch 12, and by switching mutually the developing and cleaning bias voltages, the developing property is maintained satisfactorily, and the cleaning property is improved.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a developing/cleaning device used in an electrophotographic recording device, an electrostatic recording device, etc. The present invention relates to a developing and cleaning device that performs both development and cleaning under a bias voltage.

(Prior art) Recently, in electrophotographic recording devices and electrostatic recording devices that use one-component non-magnetic toner as a developer, in order to reduce the size of the entire device, the developing device and cleaning device have been combined. Various devices equipped with a developing and cleaning device have been developed.

For example, in an electrophotographic recording device equipped with such a developing device/cleaning device, an electrostatic latent image formed by exposure on a photoconductor is first developed into a visible image by the developing device/cleaning device. . Development is performed by bringing into contact with the electrostatic latent image a monocomponent non-magnetic toner charged with a polarity opposite to that forming the electrostatic latent image. At this time, toner that is about to be attracted to the non-image area of the electrostatic latent image is prevented from being attracted by applying a predetermined developing bias voltage to the developing section, and background staining of the developed image is avoided.

The toner image obtained by development is transferred onto recording paper,
After this transfer, the toner remaining on the photoreceptor surface is
The ring image is removed from the surface of the photoreceptor under a predetermined cleaning bias voltage by the ring image and cleaning device again.

However, in such a general pre-development cleaning device, the development bias voltage applied during development and the cleaning bias voltage applied during cleaning are applied at the same voltage level. The toner adsorption potential is often insufficient. This often causes the problem that the cleaning function cannot be sufficiently thickened and good image quality cannot be obtained.

(Objective) Therefore, an object of the present invention is to provide a developing/cleaning device that can perform both the developing action and the cleaning action well.

(Structure) In order to achieve the above object, the present invention switches and sets the cleaning bias voltage to be higher than the developing bias voltage in the bias power supply that outputs the developing bias voltage and the cleaning bias voltage. The toner is separated from the surface of the photoreceptor using a larger electrostatic force than when the photoreceptor is used.

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

As shown in FIG. 1, a photoreceptor drum 1, which is rotated at a constant speed in the direction of the arrow, is surrounded by a corona charger 2 and an exposure optical system 3.
, a developing/cleaning device 4, a transfer corona discharger 5, an erase exposure device 6, and the like are arranged so as to be surrounded. The surface of the photoreceptor drum 1 is first uniformly charged to a predetermined polarity by the corona charger 2, and an exposure optical system 3 projects a document image onto the charged surface of the photoreceptor drum 1. . The surface charge of the photoreceptor drum 1 is dissipated in the light-irradiated area, but remains in the dark area, where an electrostatic latent image is formed.

This electrostatic latent image is developed into a visible image by the developing/cleaning device 4. Development is carried out by transporting monocomponent non-magnetic toner charged to the opposite polarity to the charge forming the electrostatic latent image to the developing section while adhering it to the rotating member 7 of the developing/cleaning device 4. This is done by contacting the electrolatent image. During this development, a predetermined developing bias voltage is applied to the developing section through the rotating member 7 by a bias power source 8, which will be described later.

Further, a recording paper 9 is superimposed on the toner image obtained by development, and the toner image is transferred onto the recording paper 9 by a transfer corona discharger 5 provided behind it. After the transfer, the surface of the photoreceptor drum 1 receives discharge from the corona charge remover 2 and erase light from the erase exposure device 6, so that the charges forming the electrostatic latent image are removed.

Next, the surface of the photosensitive drum 1 is sent to the developing/cleaning device 4 again without being subjected to the action of the exposure optical system 3.

In this developing/cleaning device 4, a predetermined cleaning bias voltage is applied to the rotating member 7 by a bias power source 8, which will be described later. The cleaning bias voltage removes toner remaining on the surface of the photosensitive drum 1.

The cleaned photoreceptor drum 1 is removed by a corona removal band 12.
, and preparations are made for the next recording cycle.

Next, the developing/cleaning device 4 will be explained. The rotating member 7 is provided close to the surface of the photosensitive drum 1, and a bias power source 8 is connected to the rotating member 7. This bias power supply 8 is constructed by installing a DC power supply 10 and an AC power supply 11 in parallel via a changeover switch 12, and furthermore, the AC power supply 11 is backed up by a DC power supply 13 connected in series thereto. It is biased by this. The voltage applied by the DC type 1113 is set higher than the voltage applied by the DC type [10], and as a result, the bias applied potential by the AC power supply 11 is set to be higher than the voltage applied by the DC type [10]. The potential is higher than the bias applied potential by 10.

The developing bias voltage is, for example, 50 to 50
0V is set, and the cleaning bias voltage is 100
~600V is set.

The rotating member 7 is installed at the outlet of the toner hopper 14 , and the opening of the toner hopper 14 includes a doctor blade 15 that controls or frictionally charges the toner supply port, and a doctor blade 15 that controls the toner supply port or charges the toner by friction, and transfers the toner in the toner hopper 14 to the rotating member 7 . A toner supply row 516 for supplying toner is provided.

As shown in FIG. 2, the rotating member 7 is formed by stacking an electrode 117, a dielectric layer 18, and an imager 19 in this order from the inside, and applies the developing bias voltage and cleaning to the electrode layer 17. A bias voltage is applied, and each of these voltages is applied to the microelectrodes of the development layer 19 via the dielectric layer 18 that controls the developability.

The microelectrodes are provided in an insulating binder and are electrically insulated from each other.

In the developing/cleaning device having such a configuration, during development, the changeover switch 12 of the bias power supply 8 is
is set to the DC power source 10 side, and a developing bias voltage from this DC power source 10 is applied to the rotating member 7. This prevents toner from adhering to the non-image area of the electrostatic latent image, thereby avoiding background stains on the developed image.

On the other hand, during cleaning, the changeover switch 12 of the bias power supply 8 is set to the AC power supply 11 side, and the DC power supply 13 is set to the AC power supply 11 side.
A cleaning bias voltage is applied to the rotating member 7 by the alternating current ff111 biased by. As a result, the toner remaining on the photoreceptor drum 1 is electrostatically attracted to the rotating member 7 side, and the photoreceptor drum 1 is cleaned.

In this case, since the cleaning bias voltage is set higher than the developing bias voltage, the surface of the photoreceptor drum 1 can be completely covered with a strong piascus during cleaning while preventing background stains during development using a suitable piascar. Can be cleaned.

(Effects) As described above, the developing/cleaning device according to the present invention has a bias power source that can be switched between a developing bias voltage set at a lower level and a cleaning bias voltage set at a higher level. Because it is installed,
While maintaining good developability, the cleaning performance of the photoreceptor can be improved, and extremely high quality images can be stably obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of an electrophotographic recording apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged longitudinal cross-sectional view of a rotating member. DESCRIPTION OF SYMBOLS 1... Photosensitive drum, 4... Developing and cleaning device, 7... Rotating member, 8... Bias power supply.

Claims (1)

[Claims] A developing device attaches one-component non-magnetic toner to the electrostatic latent image on the photoreceptor under a predetermined developing bias voltage, and a developing device applies a predetermined cleaning bias to remove the toner remaining on the photoreceptor after the toner image is transferred to recording paper. In a developing/cleaning device configured to double as a cleaning device that removes material from a photoreceptor under voltage, the bias power source that outputs the developing bias voltage and the cleaning bias voltage can switch and output both bias voltages. 1. A developing and cleaning device for an electrophotographic recording apparatus, characterized in that the cleaning bias voltage is set to a higher voltage value than the developing bias voltage.