JPH0252375A - Electrostatic charger output adjusting device for image forming device - Google Patents

Abstract

PURPOSE:To adjust the output of an electrostatic charger in a short time by generating a current or voltage corresponding to a control value by a supply means and then supplying it to an electrostatic charging means. CONSTITUTION:A measuring circuit 16measures a current which flows in a conductive base 15 from a photosensitive drum 11 in a corona discharging process and an electrostatic charge removing process by the electrostatic charger 12 and an electrostatic discharging lamp 13. The measurement output of this measuring circuit 16 is supplied to a control part 18 through an A/D converting circuit 17. Further, a D/A converter 21 which converts an adjustment value into an analog current or voltage is connected to a control part 18 and a high- voltage transformer 22 which supplies a necessary current or voltage to the electrostatic charger 12 is connected to this D/A converter 21. Consequently, the output of the electrostatic charger is adjusted in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Field of Industrial Application) This invention relates to an output adjustment device for a charger disposed around a photosensitive drum of an electronic copying machine, for example.

(Prior Art) Conventionally, the output adjustment of a charger for charging and a charger for transfer and peeling disposed around a photoreceptor drum has been performed using a special jig. That is, the photosensitive drum is removed from the copying machine, and an aluminum jig having the same shape as the photosensitive drum is attached. Then, corona discharge is applied to this jig using a charger, and the current value or voltage value flowing out from the jig is measured, and the measured current value or voltage value is made to match the preset value. In addition, the variable resistance of the high-voltage transformer connected to the charger had to be manually adjusted. This is because even if the voltage applied to the charger is the same, the charge charged on the photosensitive drum differs depending on the model.

However, manual adjustment using a jig as described above takes a long time and requires maintenance personnel to carry the jig and measuring instrument.

Furthermore, since the size of the photoreceptor drum varies depending on the model, the jig must be changed depending on the size of the photoreceptor drum, making adjustment work complicated.

(Problems to be Solved by the Invention) This invention is intended to solve the problems that it takes a long time to adjust the output of a charger and that a dedicated jig is required when adjusting the output. However, it is an object of the present invention to provide a charger output adjustment device for an image forming apparatus that is capable of adjusting the charger output in a short time and does not require a jig.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides an image bearing member on which an electrostatic latent image is formed, a charging means for charging the image bearing member, and a charging means for charging the image bearing member. A measuring means for measuring outflowing or inflowing current or voltage; and a control means for comparing the measured output of the measuring means with a reference value and generating a control value corresponding to the error from the reference value;
It is comprised of supply means that generates a current or voltage according to this control value and supplies it to the charging means.

(Operation) This invention measures the current or voltage flowing into or out of the image carrier by a measuring means, compares this measured value with a reference value by a control means, and sets a control value corresponding to an error with the reference value. By generating current or voltage according to this control value using the supply means and supplying it to the charging means, the output of the charger can be adjusted automatically and in a short time without using a special jig. It is considered executable.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows the main parts of an electronic copying machine to which the present invention is applied. A charger 12 for charging and a static elimination lamp 13 are arranged around the photoreceptor drum 11. The photosensitive drum 11 is rotated by a motor 14 about a conductive support 15 in the direction of the arrow shown in the figure. A measurement circuit 16 is connected to the conductive support 15, and the measurement circuit 16 causes the charging device 12 to be connected to the conductive support 15.
, the current flowing from the photoreceptor drum 11 into the conductive support 15 is measured through the corona discharge step using the static elimination lamp 13 and the static elimination step. This measurement is not limited to current values, but may also be measured as voltage values.

Incidentally, if only the value of the current flowing out of or flowing into the photosensitive drum 11 is measured, the simple configuration shown in FIG. 2 is also possible. However, in this embodiment, in addition to measuring the current value, the charging device 1
The output value of 2 is controlled.

The measurement output of the measurement circuit 16 is supplied to the control section 18 via the A/D conversion circuit 17. This control section 18 controls the entire electronic copying machine, and the motor 4, operation panel 19, storage section 20, exposure lamp (not shown), etc. are connected to this control section 18. The operation panel 19 displays a copy key to support the start of copying, a numeric keypad used to set the number of copies, a charger output adjustment mode, etc. to be described later, and the number of copies input with the numeric keypad. A display section and the like are provided. Further, the storage unit 20 is configured to store output adjustment values of the charger and the like.

Furthermore, a D/A converter 21 that converts the adjustment value into an analog current or voltage is connected to the control section 18, and the D/A converter 21 is connected to the charger 1 for charging.
A high voltage transformer 2 that supplies the required current or voltage to 2.
2 are connected. In the above configuration, the output adjustment operation of the charging device 12 will be described with reference to FIG.

When the charger output adjustment code is input from the numeric keypad on the operation panel 19, the control section 18 is set to the charger output adjustment mode, and this setting mode is displayed on the display section of the operation panel 19 (step 5TI). . In this state, the motor 4 is driven and the high voltage transformer 22
, the static elimination lamp 13 is turned on (step ST2.3),
A corona discharge process and a static elimination process are sequentially performed on the photoreceptor drum 11. Along with this, the current flowing out from the photosensitive drum 11 to the conductive support 15 (the current flowing in if it is charged with the opposite polarity) is measured by the measuring circuit 16 (step 5T4), and this measured value is measured by the A/D. The signal is supplied to the control section 18 via the converter 17. This control unit 18 compares the measured value with a preset reference value (step ST5.6), and if the measured value is outside the allowable range of the reference value, the digital value "128" is set as the adjustment value, for example. D/A
It is output to the converter 21 (step 5T7).

This D/A converter 21 generates a control current (or control voltage) corresponding to the digital value, and this control current is supplied to a high voltage transformer 22.

Then, by the output of the high voltage transformer 22 corresponding to this control current, the charging device 12 performs the corona discharge process again, and the operations of steps ST4 to ST6 are performed.

That is, the corona discharge process of the charger 12 and the static elimination process of the static elimination lamp 13 are performed in sequence, and the current flowing out from the photosensitive drum 11 is measured by the constant circuit 16, and this measured value is controlled. In section 18, it is compared with a reference value. As a result, if the measured value is lower than the reference value, for example, a digital value "192" is output as the adjustment value.
If the measured value is higher than the reference value, for example, a digital value "64'" is output as the adjustment value, and the operations of steps ST4 to ST7 are repeated. This is the relationship shown in FIG. 4, for example. Adjustment values are sequentially set according to the error between the value and the reference value, and the measured value is converged within the allowable range of the reference value using the binary search method.In this example, D/ For example, 6.
An output value of 0 (V) is supplied to the high voltage transformer 22,
This high pressure! - The output value of 450μA±4% from the lance 22 is converged to be supplied to the charging charger 12 (14MΩ).

If the above operation determines that the measured value is within the allowable range of the reference value (step 5T6), the adjustment value at this point is stored in the storage unit 20 (step 5T6).
T8), the high voltage transformer 22 and the static elimination lamp 13 are turned off, the motor 14 is stopped, and the output adjustment operation is completed.

Note that the adjustment value stored in the storage section 20 is output as the first adjustment value during the next adjustment operation.

Furthermore, during output adjustment, the exposure lamp for scanning the document is turned off and the fixing device is also stopped.

According to the above embodiment, the output of the charger is adjusted using the photosensitive drum 11. Therefore, the conventional method does not require a jig, and the work of replacing the photosensitive drum and jig during measurement can be omitted.

Further, the measuring circuit 16, the control section 18, etc. are always provided in the copying machine, and the output adjustment is automatically performed by setting the control section 18 to an output adjustment mode. Therefore, there is no need to perform work such as adjusting the variable resistance of the high voltage transformer according to the measurement results as in the past, making the adjustment work easier and reducing the time required for the adjustment work. In addition, it is possible to equalize variations in settings caused by factors of the adjuster.

Furthermore, the adjustment value obtained by the adjustment is stored in the storage unit 20, and this adjustment value is used at the time of the next adjustment to start the adjustment. Therefore, since the adjustment operation can be performed from a state where there is little error between the measured value and the reference value, the time required for adjustment can be shortened. Incidentally, in this example, the time could be reduced by one minute per unit.

Incidentally, in the above embodiment, the adjustment operation of the charger for charging has been explained, but the invention is not limited to this, and the output adjustment of the charger for transfer and the charger for peeling can be performed in the same manner as in the above embodiment. is possible.

In this case, for example, an efficient adjustment method is to turn on only the charging charger, rotate the photoreceptor drum once, and then sequentially turn on the transfer charger and the peeling charger.

It goes without saying that various other modifications can be made without departing from the gist of the invention.

[Effects of the Invention] As detailed above, according to the present invention, the measuring means measures the current or voltage flowing into or out of the image carrier, and the control means compares this measured value with a reference value. By generating a control value corresponding to the error from the reference value and using the supply means to generate a current or voltage according to this control value and supplying it to the charging means, automatic charging can be performed without using a special jig. It is possible to provide a charger output adjustment device for an image forming apparatus that can adjust the output of a charger in a targeted manner and in a short time.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of the main parts showing one embodiment of this invention, Fig. 2
The figure is a configuration diagram showing the device for measuring outflow current, and Figure 3 is a block diagram showing the device for measuring outflow current.
FIG. 4 is a diagram showing the relationship between the output value of the D/A converter and the current value flowing into the photosensitive drum. 11... Photosensitive drum, 12... Charger for charging, 1
3... Static elimination lamp, 16... Measuring circuit, 18...
Control unit, 20... Storage unit, 22... High voltage transformer. ]1

Claims (1)

[Scope of Claims] An image carrier on which an electrostatic latent image is formed, a charging device that charges the image carrier, and a measuring device that measures the current or voltage flowing into or out of the image carrier. and a control means that compares the measured output of the measuring means with a reference value and generates a control value corresponding to the error with the reference value, and generates a current or voltage according to the control value and supplies it to the charging means. A charger output adjustment device for an image forming apparatus, comprising: a supply means;