JPS59168481A - Photosensitive body device - Google Patents

Abstract

PURPOSE:To measure and adjust a photosensitive body current easily by attaching a measuring unit for the photosensitive body current to a photosensitive body detachably, nd grounding the conductive support member for a photoconductive layer automatically when the measuring unit is detached. CONSTITUTION:Values of resistances r1-r6 are adjusted corresponding to necessary discharge current values of respective corona dischargers and the measuring unit 20 is loaded in the insertion hole of a photosensitive body. The voltage impressed to a desired corona discharger is raised gradually to increase its discharge current gradually, and the increase in the discharge current is stopped moment the corresponding light emitting diode among L1-L3 starts emitting light to maintain the value fixedly, thus completing the adjustment of the discharge current. When the adjustments as to all necessary corona dischargers are completed, an attachment/detachment lever 24 is operated to draw out the measuring unit 20, and then a short-circuit piece contacts two conductive support bodies to be grounded automatically. Thus, the photosensitive body current is measured and adjusted easily.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application) The present invention relates to a photoreceptor device, and particularly to a photoreceptor device for an electrophotographic copying machine. More specifically, the present invention
The present invention relates to a photoreceptor device for an electrophotographic copying machine in which a measuring unit for detecting and measuring a current flowing from a photoconductive layer of a photoreceptor to ground is detachable.

(Prior Art) As is well known, an electrophotographic copying machine (1) uniformly charges the surface of a drum-shaped photoreceptor, and (2) exposes the front surface to imagewise light to form an electrostatic latent image. (3) developing the m-image with toner, (4) transferring and fixing the toner image to paper, (5) removing and cleaning the toner image and the charged charge remaining on the surface, etc. By operation, the copy image of the original can be repeated.

In a normal electronic multifunction machine, as shown in FIG. 1, the area around the drum-shaped photoreceptor 4 rotatably supported by the shaft 5 is charged, transferred, separated, removed, etc.
One or more corona dischargers 2°6 etc. are provided.

Corona discharger2. As is well known, I6 etc. are located in a long and narrow box-shaped metal shielding case.

It has a structure in which a discharge wire such as a tungsten wire is stretched across an electrical insulator. A DC or AC voltage of several kilovolts is applied to this discharge wire to cause corona discharge.

By the way, the total current It flowing due to the corona discharge
is made up of a current Id flowing through the photoreceptor and a current I8 flowing through the metal shield case.

Among these, the value of the photoreceptor current Id is an important factor that greatly affects the copying quality and the paper separation performance from the photoreceptor, in other words, the degree of occurrence of paper jams near the photoreceptor.

Therefore, it is necessary to adjust the value of the photoreceptor current Id to be within a predetermined range.

Note that in some cases, such as a copying machine with a slow copying speed, it may be sufficient to adjust the total current It. This is because there is a certain correlation between the total current It and the photoreceptor current Id.
This is because if the allowable range of d is wide, the photoreceptor current Id can be kept within a predetermined allowable range by adjusting the total current It to a predetermined value.

However, even if K and photoreceptor current Id are once adjusted to a certain predetermined value at the time of product shipment, the corona discharger may become dirty, the discharge wire may become deformed or deteriorated, or the environment (temperature and humidity) may change. The value of the photoreceptor current gradually changes due to a shift in the relative positional relationship of the photoreceptors. This requires readjustment of the photoreceptor current.

A conventional method for adjusting photoreceptor current will be explained with reference to FIG. The shaft 5 is also removed from the drum photoreceptor 4 shown in FIG.
Insert into.

The current measurement plate 6 is made of an electrical insulator, and includes a cylindrical portion 6a for attachment to the shaft 5, a supporting surface 6b integrally formed with the cylindrical portion 6a, and a conductive portion laminated on the outer surface of the supporting surface 6b. It is composed of layer 6C.

Then, as shown in FIG. 2, the cylindrical portion 6
The dimensions and shape are such that the surface of the conductive layer 6C is in the normal position of the surface of the drum photoreceptor 4 when the conductive layer 6C is fitted and fixed.

Therefore, as shown in the figure, with the conductive layer 856c facing the corona discharger 2, an ammeter 7 is inserted between the conductive layer 6c and the shaft 5 (generally the frame ground of the machine), and the high-voltage power source ( (not shown), the corona discharger 2 discharges, and the current Ic flowing from the discharge wire through the conductive layer 6c can be measured.

This conductive layer current Ic and the photoreceptor current I during actual copying operation
Since there is a very strong correlation between d and d, the photoreceptor current Id can be set within a predetermined tolerance range by adjusting the conductive layer current Ic to a certain value by changing the output of the high-voltage power supply. .

In addition, since the cylindrical portion 6a is rotatable around the shaft 50,
By sequentially facing the conductive layer 6c to other corona dischargers and measuring and adjusting the conductive layer current, the photoreceptor current caused by each corona discharger can be adjusted to a predetermined value.

However, the conventional method as described above has the disadvantage that it is very time-consuming, such as pulling out the drum-shaped photoreceptor 4 and inserting the current measurement plate into the shaft. Another drawback is that the photosensitive surface is easily damaged when inserted.

(Objective) The present invention is intended to improve the above-mentioned drawbacks, and an object of the present invention is to provide a photoreceptor device in which there is no need to pull out the photoreceptor even when measuring and adjusting the photoreceptor current.

(Summary) In order to achieve the above-mentioned object, in the present invention, a measurement unit for detecting and measuring the current flowing from the photoconductive layer of the photoconductor to the ground can be attached to and detached from the photoconductor, and The device is characterized in that the conductive support member of the photoconductive layer is automatically grounded when the unit is traded.

(Example) Below, the present invention will be described in detail with reference to the drawings. Third
4 and 4 are cross-sectional views of one embodiment of the present invention, FIG. 3 is a diagram showing a state in which a current measuring unit is loaded on a drum-shaped photoreceptor, and FIG. 4 is a diagram showing a state in which the current measuring unit is removed. FIG.

Further, FIG. 5 is a side view of the drum-shaped photoreceptor.

In these figures, the same reference numerals as in FIGS. 1 and 2 refer to the same or equivalent parts.

The drum photoreceptor 4 has a disc-shaped internal conductive support 11. which has a hole for fitting into the shaft 5. An annular insulating support 12 integrally fitted on the outside thereof, and a hollow cylindrical external conductive support 13 integrally fitted on the outside thereof.
A photoreceptor layer 14 formed around the outer periphery of the external conductive support 16 is also configured.

Then, a part of the P-edge support 12 is cut off to form a current measurement unit insertion hole 15. External and internal conductive supports around the current measurement unit insertion hole 15 +3.
A plurality of insulating guide rods 16 are installed on the inner surface of H (inner surface side of the drum), and shorting pieces 17 are loosely inserted into these guide rods 16.

The shorting piece 17 is always connected to the external and internal conductive supports 13 by a bias spring 18 whose one end is fixed to the tip of the guide rod 16. It is pressed toward the inner surface of II.

Therefore, it is shown in FIG. Thus, when the current measuring unit 20 is not inserted into the current measuring unit insertion hole 15, the shorting piece 17 is in conductive contact with the inner surfaces of the inner conductive support 11 and the outer conductive support 13. However, when the current measurement unit 20 is loaded (Fig. 3),
The shorting piece 17 is not in conductive contact with anything and is electrically floating.

Next, a specific example of the current measuring unit 20 suitable for the photoreceptor device of the present invention will be described with reference to FIGS. 6 and 3. FIG. 6 is an external perspective view of the current measurement unit 20, and FIG. 7 is an example of the measurement circuit.

The upper electrical contact 21 and the lower electrical contact 22 are connected to the outer conductive support 16 and the inner conductive support 11, respectively, when the electrical measurement unit 20 is loaded into the insertion hole 15.
make electrical contact with. The locking pawl 26 functions to fix the loaded current measurement unit 20 within the insertion hole 15 and prevent it from falling out.

The locking pawl 26 is interlocked with the attachment/detachment lever 24.

By operating the attachment/detachment lever 24, the conductive support 11°13
can be disengaged. L1 to L6 are LEDs (light emitting diodes) for display, and as described later, in this embodiment, the LEDs are turned on when the discharge current of the corresponding corona discharger exceeds a set value. Designed.

FIG. 7 is a block diagram showing an example of the internal circuit of the electrical measurement unit 20 shown in FIG.

When a high voltage power supply (not shown) in the main body of the copying machine is energized and a high DC or AC voltage is applied to the corona discharger, a corona discharge occurs and a discharge current flows from the photoreceptor layer 14 to the external conductive support 16. ．． The current flows through the upper electrical contact 21 to the current detection resistor R in the current measuring unit 20, and then to the lower electrical contact 2.
2 via the lower electrical contact 22 or internal conductive support 11
and flows to ground.

Therefore, the potential difference across the current detection resistor R is proportional to the corona discharge current flowing into the photoreceptor layer 14.

A portion X surrounded by a dashed line in FIG. 7 is, for example, a block for measuring charging corona discharge current.

As described above, the voltage generated across the current detection resistor R is amplified by the amplifier A1, and then compared with the reference voltage 1 at the point P1 by the comparator C1. When the output of the amplifier A1 becomes higher than the reference voltage v1, the light emitting diode L1 emits light.

Therefore, if the output voltage of the high-voltage power supply is gradually increased from a low level and the output voltage stops increasing at the moment when the light emitting diode L1 starts emitting light, the flow from the corresponding corona discharger to the photoconductor N+4 The discharge current will be set correctly to the set value.

Note that, as is clear, the reference voltage v1 at point P1 is
It can be set arbitrarily by appropriately adjusting the ratio of 1 and r2.

A portion Y surrounded by a two-dot chain line in FIG. 7 is, for example, a block for measuring corona discharge current for transfer, and its operation is similar to that of the block for measuring corona discharge current for charging described above. In this case, the reference voltage ■2 at point P2 is the resistance r3
and r4 can be arbitrarily set by adjusting the ratio.

Further, a portion 2 recessed by a dotted line in FIG. 7 is, for example, a block for measuring a corona discharge current for paper separation. AC discharge is used for corona discharge for paper separation.

Therefore, in this case, amplifier A2 amplifies the voltage across the resistor R, then full-wave rectifies it to direct current, and converts it to point P.
I am trying to compare it with reference voltage 3.6. The reference voltage V5 in this case is arbitrarily set by adjusting the voltage division ratio of the resistors r5 and r6. Other operations are similar to those described above.

As can be easily understood from the above explanation, the discharge current adjustment of each corona discharger according to the present invention is performed in the following steps.

(1) The values of the resistors r1 to r6 are adjusted according to the required discharge current value of each corona discharger.

The current measurement unit 20 is loaded into the insertion hole 15 of the drum photoreceptor 4. As a result, the contact piece 17 no longer contacts the internal conductive support 11 and the external conductive support 15, and the current detection resistor R is inserted in series between the conductive supports I+ and 13.

(2) Apply a predetermined DC or AC voltage to the corona discharger to be adjusted from the high voltage WL of the copying machine main body, gradually increase the applied voltage, and gradually increase the discharge current from a small value. let

(3) At the moment the light emitting diode corresponding to the target corona discharger begins to emit light, the increase in the discharge current is stopped and the output voltage of the high voltage power supply is stopped and fixed at that value. Thereby, the discharge current g of the corona discharger is
The adjustment is complete.

:4) Repeat the operations in (2) and (3) above for each required corona discharger.

(5) Once the discharge current adjustment settings as described above have been completed for all necessary corona dischargers, operate the attachment/detachment lever 24 to attach the current measurement unit 20 to the drum photoreceptor 4.
Pull out.

(6) When the current measuring unit 20 is pulled out, the shorting piece 17 is pulled out from the internal conductive support 1 by the force of the spring 18.
1 and an external conductive support 13, two conductive supports 11. +3 is shorted and each conductive support is automatically grounded.

In the above, an example has been described in which the shorting piece 17 is pressed toward both conductive supports by separate springs 18.
A conductive elastic material is used as the short-circuiting piece, one end of which is fixed to one conductive support (or a part with the same potential as this), and the other end is fixed to the other conductive support (-1: bamboo, this). It is clear that the structure may be such that both conductive supports are normally short-circuited by being in pressure contact with the same potential portion).

In addition, although the example in which all the circuit elements necessary for detecting the discharge current are housed in the current measurement unit 2o has been described above, the present invention is not limited to this (excluding the current detection resistor R). It is clear that all or part of the circuit elements may be placed outside the current measurement unit 20.

In other words, when adjusting the discharge current, a small current detection resistor R is loaded into the current measurement unit insertion hole 15, and the current detection resistor R is connected to the internal conductive support 11 and the external conductive support 16. It is sufficient if the configuration is such that they are inserted in series between the two.

In addition, in Fig. 7, a separate current measurement block is provided for each corona discharger, but each comparator, light emitting diode, and amplifier are shared, and various reference voltages are generated by switching the voltage dividing resistor K. If K is set so as to make it so, the circuit configuration can be greatly simplified.

Although the present invention has been described above as applied to a drum-shaped photoreceptor, it will be easily understood that the present invention can also be applied to a sheet-shaped photoreceptor.

(Effects) As is clear from the above description, according to the present invention, the following immediate effects are achieved.

(1) Since there is no need to equip each copying machine with a corona discharge current measurement circuit, costs can be reduced.

(2) During normal copying operation, corona discharge current 611
Since the constant circuit has been removed and is not subject to mechanical shock or vibration, there is no risk of damage and a longer lifespan.

(3) When the current measurement unit is removed from the drum-shaped photoreceptor, the external conductive support is automatically grounded by the shorting piece, which prevents copying failures and overcharging of the photoreceptor due to maintenance personnel forgetting to short-circuit. There is no risk of this occurring.

[Brief explanation of the drawing]

Fig. 1 is a perspective view for explaining the arrangement relationship between a drum-shaped photoreceptor and a corona discharger in a normal electrophotography format, and Fig. 2 is a perspective view for explaining a conventional corona discharge current measuring and adjusting device. Figure 4 is a perspective view of the main parts, Figure A 3 is a sectional view showing a state in which a discharge current measuring unit is loaded in a photoreceptor device according to an embodiment of the present invention, and Figure 4 is a diagram showing the state in which the discharge current measuring unit is removed from Figure 3. 5 is a sacral view of FIG. 4, FIG. 6 is a diagonal 416 external view of a discharge current measuring unit suitable for application to the photoreceptor device of the present invention, and FIG. FIG. 2 is a block diagram showing an example of the internal circuit of the discharge ammeter single constant unit. 2.6...Corona discharger, 4...Drum photoreceptor, 5...Shaft, 11...Inner conductive support, 12...Insulating support, 13...Outer conductive support Body, 14... Photoreceptor layer, 15... Current measurement unit insertion hole, 16... Guide rod, 17...
・Short piece, 18 ・・Bias splinte', 2o
...Current, measurement unit, 21...Upper electrical contact, 22...Lower electrical contact Patent attorney Michi Hiraki 1 non-person Figure 1 Figure 2 Figure 3 4 2 11' Figure 4 , 4 Figure 5 Figure 7

Claims (3)

[Claims] (1) An outer conductive support having a photoreceptor layer formed on its surface, and an inner conductive support which is integrally formed with the outer conductive support via an insulating support and is electrically grounded. ,
A current measuring unit insertion hole formed by cutting out a part of the insulating support, and a current measuring unit insertion hole on the back side of the current measuring unit insertion hole, which normally electrically shorts between the internal and external conductive supports. . A photoreceptor device comprising: a contact piece that releases the short circuit when the current measurement unit is inserted into the current measurement unit insertion hole. (2) The photoreceptor device according to claim 1, wherein the shorting piece is pressed toward the inner and outer conductive supports by a spring fixed at one end. (3) The connecting piece has one end made of a conductive elastic material fixed to the same potential as one of the internal and external conductive supports, and the other end made of a conductive elastic material fixed to the same potential as one of the internal and external conductive supports.