JPH04163472A - Sensitized substance potential control device - Google Patents

Abstract

PURPOSE:To eliminate an electrometer and to simplify internal constitution by detecting a leak current flowing from a sensitized substance to the earthing side and controlling an electrifying device to adjust a leak current to a given value. CONSTITUTION:When a sensitized drum 11 is driven, an electrifying device 13 and a stating eliminating lamp 17 are turned ON. It is detected by an ammeter 18 whether a leak current flowing from an elementary pipe 11a of the drum 11 to the earthing side is equal to a given current value. In which case, when the leak current is not equal to the given value, the output voltage of the electrifying device 13 is regulated so that it is equal to the given value. In this case, when the electrifying device 13 is turned ON and an exposure lamp 12 is turned ON, the surface potential of the drum 11 is increased. The set values of the output voltages of the electrifying device 13 and the lamp 12 are stored in a RAM and read by a CPU 19 to control a leak current. In which case, the electrifying device 13 is controlled so that the electrifying potential of the drum 11 is adjusted to an optimum value, an electrometer is eliminated, and internal constitution is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photoreceptor potential control device in an electrophotographic process such as a copying machine or a laser printer.

[Prior Art] Generally, in the electrophotographic process of copying machines and the like, an electrostatic latent image of an image is formed on a photoreceptor such as a drum and toner is attached to the photoreceptor, so that the image can be processed without losing the gradation. The potential of the photoreceptor must be controlled to ensure clear transfer to paper and to extend the life of the photoreceptor.

A conventional photoconductor potential control device is equipped with an electrometer near the photoconductor, and charges or removes static electricity on the surface of the photoconductor based on the potential measured by the electrometer, so that the potential of the photoconductor reaches a predetermined level. electrical potential.

[Problems to be Solved by the Invention] However, in the conventional photoconductor potential control device described above, there is a problem that the internal configuration of a copying machine etc. becomes complicated because it is necessary to install an electrometer near the photoconductor. .

SUMMARY OF THE INVENTION In view of the problems with the conventional photoconductor potential control device, an object of the present invention is to provide a photoconductor potential control device that does not include an electrometer and can simplify the internal configuration of a copying machine or the like.

[Means for Solving the Problems] The present invention includes a detection means for detecting a leakage current flowing from a photoreceptor to a ground side, and a control means for controlling a charger based on the leakage current detected by the detection means. and
The control means is achieved by a photoreceptor potential control device configured to control the output voltage of the charger so that the detected leakage current is equal to a predetermined value.

The present invention includes a pressure detection means for detecting a leakage current flowing from the photoreceptor to the ground side, and a control means for controlling an exposure light source based on the leakage current detected by the detection means. This can also be achieved by a photoconductor potential control device configured to control the pressure voltage of the exposure light source so that the detected leakage current becomes equal to a predetermined value.

The control means according to the present invention may be configured to control the developing bias so that toner in the developing device does not adhere to the photoreceptor during correction of the exposure potential of the photoreceptor.

[Function] In the first invention, the detection means detects the leakage current flowing from the photoreceptor to the ground side, and the control means controls the leakage current from the charger to the photoreceptor so that the leakage current detected by the detection means is equal to a predetermined value. Outputs voltage to.

In the second invention, the detection means detects a leakage current flowing from the photoreceptor to the ground side, and the control means applies a voltage from the exposure light source to the photoreceptor so that the leakage current detected by the detection means is equal to a predetermined value. Output.

The above-mentioned control means controls the developing bias so that the toner of the developing device does not adhere to the photoreceptor during correction of the exposure potential of the photoreceptor [Embodiment] Hereinafter, one embodiment of the photoreceptor potential control device of the present invention will be described. will be explained in detail with reference to the drawings.

FIG. 1 is a flowchart for explaining the operation of the photoreceptor potential control device of this embodiment.

FIG. 2 is a diagram showing the configuration of the photoreceptor potential control device of this embodiment.

First, the configuration of the photoreceptor potential control device of this embodiment will be explained with reference to FIG.

A photosensitive drum 11 as a photosensitive member, an exposure light source unit 12 as an exposure light source, and a charger (main charger)
13, a developing device 15 equipped with a roller 14, a transfer device 16, a static elimination lamp 17, an ammeter 18 as a detection means, and a CPU (central processing unit) 19 as a control means.

Next, the operation of each of the above-mentioned components will be explained.

The photosensitive drum 11 as a photosensitive member is configured to rotate clockwise in a rotation direction A by a driving means (not shown) such as a motor.

The light source unit 12 irradiates the surface of the photosensitive drum 11 with light so as to form an electrostatic latent image on the surface of the photosensitive drum 11 .

The charger 13 sequentially charges the surface of the photosensitive drum 11 along the rotation direction A in the dark.

The developing device 15 transfers toner to the photosensitive drum 1 using a roller 14.
1, and the electrostatic latent image formed above is visualized.

The transfer device 16 transfers the toner adhering to the surface of the photosensitive drum 11 onto a sheet of paper.

The charge eliminating lamp 17 removes the charge remaining on the surface of the photosensitive drum 11.

The ammeter 18 detects a leakage current flowing from the raw tube 11a of the photosensitive drum 11 to the ground side.

The CPU 19 controls the light source unit 12 and the charger 13 based on the leakage current flowing through the ammeter 18 .

Hereinafter, the operation of the photoreceptor potential control device shown in FIG.
9 will be mainly explained with reference to FIG. 2.

First, the photosensitive drum 11 is turned on and driven (step Sl).

After the photosensitive drum 11 is driven, the charger 13 is turned on (step S2) and the static elimination lamp 17 is turned on (
Step S3).

Next, the leakage current (2) of the photosensitive drum 11 flowing from the raw tube 11a of the photosensitive drum 11 to the ground side is detected by the ammeter 18 (step S4), and the value of the leakage current (2) is a predetermined leakage current value I. Detect whether it is equal to (step S5)
.

In this embodiment, the predetermined leakage current value ■. approximately 68 μA (
Microamps).

In step S5, the value of leak current I or a predetermined leak current value is determined. If they are not equal, the output voltage VMC of the charger 13 is adjusted so that they become equal (step S6).

In this embodiment, the output voltage VMC of the charger 13 is set to about -60
By setting it to 0■, the predetermined leakage current value ID can be set to about 68 μA.

According to the detection result in step S5, the value of leak current I is a predetermined leak current value ■. When it is equal to , the process advances to step S7, which will be described later.

Each of the steps 81 to S6 described above represents each step in controlling the charging potential with respect to the developing bias potential shown in FIG. 3 (FIG. 3 will be described later).

Next, the charger 13 is turned on while maintaining the output voltage Vy (step S7), and then the exposure lamp 12 is turned on (step S8). When the exposure lamp 12 is turned on, the surface potential of the photosensitive drum 11 or rise (move in a positive direction).

After the above step S8, the blank tube 11 of the photosensitive drum 11 is
Leakage current I flowing from a to the ground side. is detected by the ammeter 18 (Step S9), and it is detected whether the value of the leakage current meter 8 is equal to a predetermined leakage current value I (Step 510).

In this embodiment, the predetermined leakage current value (2) is set to 61 μA.

In the above step SIO, leakage current 1. When the value of is not equal to the predetermined leakage current value IE, the leakage current I.

The output voltage 3 of the exposure lamp 12 is adjusted so that the value of is equal to the predetermined leakage current value I0 (step 511
).

Based on the detection results of step SIO mentioned above, the leakage current was repaired.

When the value of is equal to the predetermined leakage current value I, the process proceeds to step S12, which will be described later.

Each of the steps from step 87 to Sit described above represents each step in controlling the light level potential with respect to the developing bias potential shown in FIG. 4 (FIG. 4 will be described later).

The set value of the output voltage MC of the charger 13 obtained in step S6 and the set value of the output voltage 3 of the exposure lamp 12 obtained in step Sll are stored in a storage means (not shown) such as a RAM ( Step 512).

Next, a method of controlling the above-mentioned photoreceptor potential control device will be explained with reference to FIGS. 3 and 4.

As shown in FIG. 3, when the charger 13 is turned on by the CPU 19 at time t1 while the photosensitive drum 11 is rotating, the charger 13 changes the surface of the photosensitive drum 11 depending on the quality of the material forming the surface. The potential on the surface of the photosensitive drum 11 is charged to a corresponding potential (hereinafter referred to as surface potential).
becomes a charging potential of 20 (approximately -600 V in this embodiment).

After the surface of the photosensitive drum 11 is charged to the charging potential 20, the static elimination lamp 17 is turned on at time t2, and light is irradiated from the static elimination lamp 17 onto the surface of the photosensitive drum 11, so that the surface potential of the photosensitive drum 11 is approximately The residual potential becomes 21 between -50 and -100V. Also, at the same time t2, the photosensitive drum 11
A leakage current is generated from the raw pipe 11a to the ground side.

The charge corresponding to the potential difference between the charging potential 20 and the residual potential 21 has a correlation with the leakage current, and as shown in FIG. 5, the leakage current is approximately proportional to the surface potential of the photosensitive drum 11. .

The leakage current between the photosensitive drum 11 and the ground side is measured by the ammeter 1.
8, the CPU 19 controls the grid voltage of the charger 13 and changes the output of the charger 13 so that the current value corresponds to the leakage current detected by the ammeter 18 or the desired charging potential 20. let

4 shows the relationship between the developing bias potential and the light level potential of the surface potential of the photosensitive drum.

As shown in the figure, first, at time t4, the charger 13
19, the photosensitive drum 11 is turned on, and the surface potential of the photosensitive drum 11 becomes a charging potential 20.

Furthermore, when the light source unit 12 is turned on by the CPU 19 at time t, the light source unit 12
expose the surface of the

The surface potential of the photosensitive drum 11 irradiated by the light source unit 12 decreases depending on the density of the image formed on the surface of the photosensitive drum 11. This reduced surface potential is set to a light level potential 22 (approximately -50 to -100 in this example).
V). At time t5, a leak current flows from the raw tube 11a of the photosensitive drum 11 to the ground side.

At time t6, the charger 13 is turned on again, and the surface potential of the photosensitive drum 11 rises to the charging potential 20, and at time t
When the light source unit 12 is turned on at step 7, the surface potential of the photosensitive drum 11 decreases to the light level potential 21 again. Further, at time t7, a leak current flows from the raw tube 11a of the photosensitive drum 11 to the ground side.

The CPU 19 controls the charging potential 20 on the surface of the photosensitive drum 11.
The output level of the light source unit 12 is changed so that the difference between the light level potential 22 and the light level potential 22 becomes a desired potential difference.

The above-mentioned control of the light source unit 12 and the static elimination lamp 17 by the CPU 19 is configured to be performed every time a device such as a copying machine is turned on or every time a predetermined number of copies are made.

Normally, the developing bias potential 23 is a constant voltage (approximately -400V in this embodiment), so by controlling only the light source unit 12, the developing bias potential 23 and the light level potential 2
2 can be adjusted to the optimum value.

In addition, by controlling only the charger 13, the charging potential 2
The difference between 0 and the developing bias potential 23 can be adjusted to an optimal value.

As described above, in a reversal developing system such as a printer, fogging, carrier adhesion, etc. can be prevented by controlling the difference between the charging potential 20 and the developing bias potential 23 to an optimum value.

Further, by controlling the difference between the developing bias potential 23 and the light level potential 22 to an optimum value, the copy density can be controlled to an optimum value.

When adjusting the difference between the developing bias potential 23 and the light level potential 22, a toner image is formed on the surface of the photosensitive drum 11 and toner consumption increases, but the developing bias is controlled and set to a floating state. or developing device 15
By controlling and stopping the roller 14, toner consumption can be prevented.

C Effects of the Invention] The present invention includes a detection means for detecting leakage current flowing from the photoconductor to the ground side, and a control means for controlling the charger based on the leakage current detected by the detection means, and the control means includes a detection means for controlling the charger based on the leakage current detected by the detection means. The charger is configured to control the output voltage of the charger so that the leakage current becomes equal to a predetermined value, so the charger is controlled so that the leakage current causes the charging potential of the photoreceptor to reach an optimal value. As a result, the internal configuration of a copying machine or the like can be simplified.

The device includes a detection means for detecting leakage current flowing from the photoreceptor to the ground side, and a control means for controlling the exposure light source based on the leakage current detected by the detection means, and the control means is configured to detect the leakage current flowing from the photoreceptor to the ground side. Since the output voltage of the exposure light source is controlled so that the voltage is equal to a predetermined value, the exposure potential of the photoreceptor is controlled to the optimum value by the leakage current flowing from the photoreceptor to the ground side. As a result, the internal configuration of a copying machine or the like can be simplified.

Further, since the control means controls the developing bias so that the toner of the developing device does not adhere to the photoreceptor during correction of the exposure potential of the photoreceptor, toner consumption can be prevented.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a flowchart for explaining the operation of the photoconductor potential control device of the present invention, and FIG. 2 shows the configuration of an embodiment of the photoconductor potential control device of the present invention. 3 is an explanatory diagram when the charger is controlled by the photoconductor potential control device shown in FIG. 1, and FIG. 4 is an explanatory diagram when the light source unit is controlled by the photoconductor potential control device shown in FIG. 1. FIG. 5 is a graph showing the relationship between the leakage current and the surface potential of the photoreceptor. 11... Photosensitive drum, 12... Light source unit, 13
...Charger, 14...Roller, 15...Developer,
16... Transfer device, 17... Static elimination lamp, 18...
Ammeter, 19...CPU0 Figure 1:

Claims (3)

[Claims] (1) It includes a detection means for detecting a leakage current flowing from the photoconductor to the ground side, and a control means for controlling a charger based on the leakage current detected by the detection means, and the control means includes: A photoconductor potential control device, characterized in that the photoconductor potential control device is configured to control an output voltage of the charger so that the detected leakage current becomes equal to a predetermined value. (2) A detection means for detecting a leakage current flowing from the photoconductor to the ground side, and a control means for controlling an exposure light source based on the leakage current detected by the detection means, the control means comprising: A photoreceptor potential control device, characterized in that it is configured to control an output voltage of the exposure light source so that the detected leakage current becomes equal to a predetermined value. (3) The photoconductor according to claim 1 or 2, wherein the control means controls a developing bias so that toner in a developing device does not adhere to the photoconductor during correction of the exposure potential of the photoconductor. Body potential control device.