JPH0643746A - Developing device - Google Patents

Abstract

PURPOSE:To detect the electrostatic charged amount of one-component type toner in a developing device by aging and sufficiently electrostatically charging the toner even at the time of starting development. CONSTITUTION:While the toner 20 in a housing 30 is stirred by a rotating blade 60, it is carried to a supply roller 50 side so as to develop a latent image on a photosensitive drum 10 by a developing roller 40. The toner stirred in the housing 30 rubs on a conductive thin layer 70, which is electrostatically charged. The electrostatically charged amount of the layer 70 is measured by a current amount integrator 80, and the electrostatically charged amount of the toner 20 is estimated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as a printer, a facsimile, an electrophotographic copying machine, and more particularly, to an electrostatic latent image formed on a photosensitive member.
The present invention relates to a developing device that develops using component-based toner.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic copying machine or a laser printer, a one-component toner, especially a non-magnetic toner, is used to develop an electrostatic latent image formed on a photosensitive drum. Phenomenon method is adopted.

In a developing device using a non-magnetic one-component toner, toner is contained in a housing, and the toner is agitated by an agitating member so that it is triboelectrically charged. The triboelectrically charged toner forms a thin layer on the surface of the developing roller arranged in the housing and is conveyed to the photosensitive drum. A predetermined bias voltage is applied to the developing roller with respect to the photosensitive drum. When a thin layer of toner conveyed on the surface of the developing roller contacts the photosensitive drum, the toner on the surface of the developing roller is It is attached to the electrostatic latent image on the photoconductor drum by the bias voltage applied to. As a result, the latent image on the photosensitive drum is developed with toner.

In an image forming apparatus equipped with a developing device that uses such a one-component toner, when toner is developed by the developing device, a toner image is transferred to recording paper,
It is designed to be fixed by a fixing device. In the image forming apparatus, when the main switch is turned on, the image forming apparatus is in a standby state in which the image forming operation is not performed until the fixing apparatus rises to a predetermined fixing temperature. Then, during this standby state, the developing device performs aging in which the toner is agitated so as to have a predetermined charge amount. This aging usually has a fixing temperature of, for example, 165 ° C in the standby state.
When the temperature reaches the temperature of 1, the fixing temperature reaches 180 ° C. and the standby state ends, and at the same time, the aging ends.

[0005]

When the toner in the developing device is aged in this way, the amount of charge on the toner is affected by the time during which the fixing temperature rises. For example, when the ambient temperature is high as in the summer, the aging time is shortened and the toner may not be sufficiently charged. When the toner is in a high humidity state, the toner is not sufficiently agitated, and when the aging time is short, the toner is significantly insufficiently charged. When the image forming operation is started in such a state, the formed image is not Image defects such as fogging occur.

The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a developing device capable of sufficiently charging a one-component toner by aging even at the start of development.

[0007]

The phenomenon device according to the present invention comprises:
A housing containing a component type toner, a stirring member for stirring and charging the toner in the housing, and a stirring member are disposed in the housing, and a thin layer of the one component type toner is formed on the surface thereof to form a photoconductor. A developing roller that is conveyed to the housing, and a conductive member that is disposed in the housing so as to be frictionally charged by the toner that is stirred by the stirring member,
And a means for detecting the charge amount of the conductive member, whereby the above object is achieved.

[0008]

The toner in the housing is agitated by the agitating member and frictionally charged. At the same time, the toner is brought into sliding contact with the conductive member, so that the conductive member is triboelectrically charged. The charge amount of the conductive member is detected by the detection means, and the charge amount of the toner in the housing is estimated.

[0009]

EXAMPLES The present invention will be described below with reference to examples. As shown in FIG. 1, the phenomenon device of the present invention includes a housing 30 that accommodates the one-component non-magnetic toner 20.
The housing 30 is provided with an opening 31 at a portion facing the photoconductor drum 10.

The photosensitive drum 10 in the housing 30
A phenomenon roller 40 made of a conductive elastic material is provided in the side portion close to. The developing roller 40 is in contact with the photoconductor drum 10 through the opening 31, and the phenomenon roller 40 is rotated synchronously with the photoconductor drum 10 so that their contact surfaces move in the same direction. . A sub-roller 50, which is in pressure contact with the lower part of the developing roller 40, is arranged on the far side of the developing roller 40 from the photosensitive drum 10. The sub-roller 50 is rotated in the same direction as the developing roller so that the contact surfaces of the developing roller 40 move in opposite directions.

Three agitating chambers 32 each having an arcuate bottom face are continuously provided in the horizontal direction on the far side of the sub roller 50 from the developing roller 40. A rotary blade 60 is provided in each stirring chamber 32, and each rotary blade 6
In the case of 0, the toner 20 in the stirring chamber 32 is stirred to be negatively charged. The toner that has sequentially passed through the stirring chambers 32 by the rotating blades 60 is supplied to the sub roller 50.

A bias voltage of, for example, + 400V is applied to the sub-roller 50, and a voltage of + 200V, which is lower than the bias voltage applied to the sub-roller 40, is applied to the developing roller 40 to which the sub-roller 50 is pressed. ing.

The charged toner supplied to the sub roller 50 is conveyed to the surface of the developing roller 40 by the electric field between the sub roller 50 and the developing roller 40.

Above the sub roller 40, the developing roller 4
A blade 41 for thinning the toner conveyed on the 0 surface is provided so as to be in sliding contact with the developing roller 40. The charged toner, which is conveyed while thinning the surface of the developing roller 40, comes into contact with the portion of the photosensitive drum 10 where the electrostatic latent image is formed by pressure, and is biased by the bias voltage applied to the developing roller 40. Attached to 10. As a result, the latent image on the surface of the photoconductor drum 10 is developed with toner. The toner carried on the surface of the developing roller 40 without being attached to the photoconductor drum 10 is scraped off by the sub roller 40.

On the arc-shaped bottom surface of each stirring chamber 32,
Each conductive thin layer 70 is covered. As the electroconductive thin layer 70, for example, a coating of electroconductive fluorine is used. The electroconductive thin layer 70 is in contact with the toner 20 which is stirred and charged by the rotating blade 60 in the stirring chamber 32. The conductive thin layer 70 includes a housing 30.
It is connected to a current amount integrator 80 provided outside. The current amount integrator 80 detects a charge amount (current amount) generated on the conductive thin layer 70 due to friction with the toner inside the housing 30 when the toner is stirred and charged by the rotating blade 60. To do. The output of the current amount integrator 80 is given to the control unit 81 provided in the image forming apparatus.

In the image forming apparatus equipped with the developing device having such a structure, the developing device forms a toner image on the photosensitive drum and transfers the toner image onto the recording paper. The toner image transferred onto the recording paper is fixed on the recording paper by the fixing device. Then, in the image forming apparatus, the measurement result of the current amount integrator 80 is used for the control of the aging which is performed during the standby state until the image formation becomes possible after the main switch is turned on.

When the fixing temperature reaches the primary temperature (for example, 165 ° C.) after the main switch is turned on, the rotary blade 60 is rotated to charge the toner in the developing device, and the aging of the toner is started. When the aging is started, the toner 20 is stirred in the three stirring chambers 34 of the housing 30 by the rotation of the rotary blade 60. The toner 20 is positively charged by being stirred, and the conductive thin layer 70 is charged by the stirred toner 20 slidingly contacting the conductive thin layer 70. Then, the charges generated in the conductive thin layer 70 sequentially flow into the current amount integrator 80. The current amount integrator 80 integrates the current amount so as to measure the total amount of inflowing charges. Then, the total amount of current measured by the current integrator 80 is
As shown in FIG. 2, when the predetermined level L is reached, it is assumed that the toner 20 in the developing device is in a predetermined charged state.
Aging is ended. Further, even if the total amount of current measured by the current amount integrator 80 does not reach the predetermined level L, the level of the total amount of current becomes constant over a predetermined time as shown by the broken line in FIG. At the time
Assuming that the toner 20 is in a predetermined charged state,
Aging is ended.

At this time, if the fixing temperature in the fixing device has already reached the predetermined temperature (180 ° C.), it is determined that the image can be formed, the standby state is ended, and the image can be formed. . Further, when the total amount of current by the current amount integrator 80 reaches the predetermined level L, the standby state of the image forming apparatus is continued until the fixing temperature in the fixing apparatus reaches a predetermined temperature (180 ° C.), and the fixing apparatus is fixed. The standby state is released when the fixing temperature reaches the predetermined temperature.

As described above, when the standby state is released in the image forming apparatus, the toner is in the predetermined charging state in the developing apparatus, and a clear image is formed even if the image forming operation is immediately started. It

In the above embodiment, the charge amount of the toner is detected by the charge amount of the conductive thin layer 70 coated on the bottom surface of each stirring chamber 32. The rotary blades 60 may be made of a conductive material and the charge amount of the toner may be detected based on the charge amount of each rotary blade 60.

[0021]

As described above, in the developing device of the present invention, the charge amount of the toner can be estimated based on the charge amount of the conductive member provided in the housing for containing the toner that is frictionally charged by the toner. In addition, the toner can be reliably made to have a predetermined charge amount by aging.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a developing device of the present invention.

FIG. 2 is a graph showing a change over time in the charge amount of a conductive thin layer.

[Explanation of symbols]

 10 Photoreceptor Drum 20 Toner 30 Housing 40 Developing Roller 50 Supply Roller 60 Rotating Bud 70 Conductive Thin Layer 80 Current Amount Integrator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Koichi Baba, 1-228 Tamatsukuri, Chuo-ku, Osaka-shi Mita Engineering Co., Ltd. (72) Yuuki Ito 1-2-28 Tamatsukuri, Chuo-ku, Osaka Within Mita Engineering Co., Ltd.

Claims (1)

[Claims] 1. A housing containing a one-component toner, an agitating member for agitating and charging the toner in the housing, and a thin layer of the one-component toner disposed on the surface of the housing. A developing roller that forms a sheet and conveys it to the photosensitive member, a conductive member disposed in the housing so as to be frictionally charged by the toner stirred by the stirring member, and a detection amount of the conductive member. And a developing device.