JPS58120269A - Charge voltage controller for electronic copying machine - Google Patents

Abstract

PURPOSE:To stabilize certainly the surface potential of a photoreceptor, by changing the output voltage of a high voltage power source by a predetermined quantity and detecting the change of the surface potential of the photoreceptor for this change and performing the operation based on this detection. CONSTITUTION:The output voltage of a high voltage power source 10 for changing is changed by a predetermined quantity, and the change of the surface potential of a photosensitive drum 1 at this time is detected, and a functional relation of the surface potential to a charge current is estimated on a basis of said variation. A charge current i0 required for a set target surface potential V0 is operated in a circuit 9 on a basis of this relation and is set. Thus, the surface potential of the photosensitive drum 1 is stabilized certainly within a prescribed time after the start of the control of the high voltage power source 10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a charging voltage control device for maintaining the surface potential of a photoreceptor at a constant value in a child copying machine.

The Seiko copier uses a charger to charge the surface of a photoreceptor drum to a certain level, irradiates and exposes it with imagewise light, forms an electrostatic fII image on the surface of the photoreceptor drum, and transfers this to toner. A copy is obtained by developing and fixing the image. .

In this case, you get 1# of copies! The concentration and background density are determined by the surface potential of the photosensitive drum during development, so in order to obtain good copies of the desired quality, it is necessary to control the surface potential of the photosensitive drum to the surface potential of the photosensitive drum. is necessary.

In order to maintain good image quality of copies, conventionally, the charging high-voltage power supply connected to the charger was powered by wax pressure or constant direct current.

However, in general, the specific resistance and sensitivity of a photoreceptor are affected by temperature, wet curtains, etc.
Since the # of the photoreceptor drum in the developing section changes greatly depending on usage time, changes over time, etc., even if the Teiden voltage power supply is made constant voltage and constant current, the #! It is difficult to maintain the surface potential at a predetermined value.

To improve this, the surface potential of the photoreceptor is now #
Add 1 and, based on the measurement results, set the voltage, etc. to be applied to the charger as 11! ! It is widely practiced to control the surface potential of the photoreceptor to a set value by doing so.

However, the distance between the surface potential detector and #electric device is a certain distance due to the configuration of the photographic camera. Therefore, the surface potential control point and detection point should be separated by 1f.
I111i9 dead time lI! The drawback is that the element becomes large. This poses a major hurdle in the implementation of automatic control system configurations.

In other words, in the conventional DLLJ control method, the time from the start of control of the 4-voltage power supply to its output, that is, the stabilization of the surface potential of the photoconductor, changes due to changes in the sensitivity and specific resistance of the photoconductor, etc. The object of the present invention is to eliminate the drawbacks of the prior art described above, and
After starting the control of the high-voltage power supply, the charging-pressure operation # that can definitely stabilize the photoconductor surface 1i1i1 within a predetermined time! I'm trying to get Ill.

In order to achieve the above object, the present invention changes the output voltage of the high voltage power supply by a predetermined amount, detects the change in the surface position of the photoreceptor at this time, and calculates the cumulative current vs. Estimates the functional relationship of the surface potential and calculates the charging current required to maintain the set target machine surface potential based on this.
I am asking you to configure the settings.

Below, this Sa@ will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

In the figure, l is a photosensitive drum, 2 is a 4111 device,
3 is a surface potential sensor, 4 is an exposure unit, 4A is an imagewise light, 5 is a developer, 9 is an arithmetic control device, 91 is a Φ converter, 9
2 is an arithmetic processing unit, 93 is a VA converter, 10 is l\j
There is a high voltage power supply for IE. Further, an arrow Rv'i indicates the rotation direction of the photosensitive drum 10.

As is well known, the relationship between the current and the -a surface potential of the photosensitive drum 1 is a linear relationship as shown in FIG. 2 in the proximal direction.

The relationship 0 changes once as t[m1~■ depending on the VC such as manufacturing, variations in the photoreceptor, aging, etc.

Furthermore, there is a certain relationship between the charging current that is the output of the low-voltage power source 10 and the control voltage that is input to the threshold.

For convenience of explanation, if the relationship between the deposited wax flow and the control voltage is also approximated by a linear equation as shown in FIG. Formula % Formula % (1) However, a and b can be approximated by constants.

r, that is, in the M2 diagram, the photosensitive drum surface electric mouse and #I
The fact that the relationship with Toku Waterfall changes like a straight line ■ to ■ means that the coefficient a of the approximation equation - (1) above.

There is no other way than that b changes.

Therefore, due to the + stage in the above equation (1),
If la and b can be determined, the antacid pressure e is required to set the surface potential V of a certain photosensitive drum to the set value v0. (Thus, the required Teiden can flow) can be determined without knowing its characteristics.

The present invention has been made based on the above considerations.

When the power is turned on during operation (time 10 in the diagram s43), a predetermined arbitrary control voltage IB'l is output from the arithmetic processing Jl[92 of the arithmetic and control unit 9.

This control voltage eμ,l)/A converter 93 converts the control voltage into an analog signal and supplies it to the weighing high-voltage power source IO.

Therefore, the Teiden bird pressure power source IO supplies a charging current of magnitude 11 to the photoreceptor drum 1 via the Teiden device 2.

Here, the surface potential-charging tIL characteristic of the photoreceptor drum 1 is of course unknown, but if we assume that the direct dl [[ in Figure 2] is satisfied, from Figure 2, the rise time into which the surface potential is inserted can be calculated as follows. (See Figure 3) Move up to Vl.

The surface potential (1) is detected by the surface potential sensor 3, and is stored in the arithmetic processing section 92 via the A/D converter 91. At this time, as is clear, the following equation (2) holds true.

V1= as 1 + b・・・・・・・・・・・・
...(2) Continuing to the time ET, the arithmetic processing section m 92
changes the control voltage from el to el. In the same manner as described above, the field current changes to 1, and the surface of the photosensitive drum 1
The fi potential becomes Vl. The surface potential V is similarly detected by the surface potential detector 3 and stored in the arithmetic processing section 92.

At this time, the following equation (3) holds true.

v1= ael +b ・・・・・・・・・・・・
...(3) As is clear, the above (2) and (3)
By combining the equations, the following equations (4) and (5) are obtained: I7! La and b can be found.

81 - el b = Vl - ael 62 el These calculations can of course be performed by the calculation processing section 92. Through the above processing, the functional relationship between the control voltage e and the surface level V of the photoreceptor 10 has been determined.

Therefore, the control voltage e required to obtain the target surface potential v, ) t. In the arithmetic processing unit 92, the following (6
) can be easily obtained by performing the calculation of the formula.

e(1=(V(1b)/a...
・・・・・・・・・・・・＜6) The control voltage obtained by applying V as above. is converted into an analog signal by the D/A converter 93, and then sent to the charging high voltage electricity 111.
0.

As a result, the fluorescent current is adjusted to i@ (see the diagram JlEZ), and the surface potential of the photosensitive drum 10 is set to a desired value v0.

Now, the time interval for reading the surface potential is C1)
(2) Charging time of electric device (3) Rising time of surface potential sensor (4) Time required for a certain point on the photosensitive drum to change from the amount of charge to the potential sensor 411III As is clear from the above description, according to the present invention, -
By simply changing the pressure (i.e., charge #LI51), measuring the surface potential of the photoreceptor drum corresponding to each twice, and performing calculations based on this, it is possible to set the predetermined position. can be set to a value of

Therefore, even if the characteristics of the photosensitive drum change significantly, problems such as an increase in the time required for the surface potential to stabilize will not occur. As a result, it becomes possible to use photoreceptors with large bounce, which could not be used with conventional devices.

In the above, the surface potential sensor is placed in front of the exposure section (upstream 1
We have described an example in which the surface potential sensor is placed at It is clear that by detecting the potential and performing similar control, it is possible to control the front side of the portion corresponding to the bright portion (white portion) of the copy to a desired value. In this case, the intensity of the bright part of the copy, that is, the background, is kept constant l1
1! Ik can be done.

In addition, in the above, the table dIJ potential-Teiden turtle current characteristic was approximated by a linear equation, but even if it is approximated by other functional relationships (quadratic equation, hyperbolic function, etc.), the same normal voltage III control can be achieved. It should be obvious that it can be done. However, in this case, in the rounding to determine the unknown coefficient, the control voltage 'lc is varied in an order of magnitude according to the order of the function, and the surface potential is read.
An operation is required to determine the functional relationship (coefficient).

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between the charging current of the photoreceptor drum, the surface potential, and the high pressure It pressure, and FIG. 3 is a detailed diagram of the present invention. I have a timing chart that I can't explain. 1... Photosensitive drum, 2... Charger, 3... Surface potential sensor, 4... Exposure section, 5... -IAm device, 9...
...Arithmetic control iron-191...A/D converter, 92
...Arithmetic processing unit, 93...D/A converter, lO
...Charging high-voltage power supply fee, patent attorney Michihito Hiraki, and 1 other person 21 Figure 311 ToT, T2 time 2 -r2I

Claims (1)

[Claims] (1) How the MA light body moves! This is a four-voltage control device for controlling the electric charge of an identification copying machine, which includes a charging device 6 disposed along the noodle, a surface potential sensor, an iA imager, etc. , the output of the high voltage power supply is m
means for generating a control voltage to control J; means for storing a functional relationship including an unknown coefficient between the surface potential and the control voltage; and 8tli! Controlling the overpressure generation means to output a plurality of control voltages, and calculating the unknown coefficient of the functional relationship from the control voltage 2 of the plurality of #i floors and the corresponding output of each surface potential cell. , FIi], and determine the surface potential m* based on the determined functional relationship.
A Teiden Swing Pressure Swing Leg System for Seiko-4 aircraft, characterized in that it is equipped with means for calculating +tijl14 pressure necessary to achieve the above-mentioned pressure and controlling the side pressure generating hand screw based on this. .