JPS61140854A - Device for inspecting electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To inspect automatically and surely the photosensitive layer of a photosensitive body by detecting the electrostatic charge quantity corresponding to the abnormal state of the photosensitive layer from the potential of a detection electrode. CONSTITUTION:The negative charge corresponding to the electrostatic charge quantity is induced by the electrostatic induction in the part of the detection electrode 601 where the electrode faces the photosensitive layer 1b when the part of the photosensitive layer 1b where the layer is electrostatically charged with positive charge by an electrostatic charger 3 comes to the position where the layer faces the detection electrode 601. Then the potential of the gate G of an FET603 increases and the drain current thereof increases, resulting in the increased output voltage E of the FET603. The voltage E fluctuates according to the electrostatic charge quantity of the part where the photosensitive layer 1b faces the detection electrode 601. When an abnormal part such as stripping, injury of recess exists in the photosensitive layer 1b, the electrostatic charge quantity is small in the abnormal part and therefore the output voltage E decreases as compared to the case in which the electrostatic charge quantity is large when said part faces the detection electrode 601.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to an apparatus for inspecting abnormalities in a photosensitive layer in a photoreceptor, which causes defects in electrophotographic images;
In particular, the present invention relates to an apparatus configuration that can easily perform an inspection without impairing the commercial value of a photoreceptor, and can perform this inspection with high resolution.

[Prior art and its problems]

In electrophotography, if there are any abnormalities such as scratches, dents, cavities, peeling, or adhesion of foreign matter on the photosensitive layer formed using a photoconductor on the surface of a photoreceptor such as a photosensitive drum, part of the obtained image may be damaged. A phenomenon occurs when the area becomes blank, so-called white areas.

For this reason, in order to inspect the presence or absence of the above-mentioned abnormalities in the photosensitive layer, conventional methods include visual inspection performed directly or via an optical device, and methods such as mounting a photoreceptor in a copying machine and actually obtaining a copied image. , an inspection method that visually evaluates this has been adopted, but the former method has problems such as the inability to clearly define the relationship between the state of image defects and the state of defects on the surface of the photosensitive layer, and the inspection being performed manually. However, the latter method has the problem of individual differences in test results and the inability to perform tests with good reproducibility.The latter method also has the problem of not being able to perform tests with good reproducibility due to individual differences in test results.The latter method has the problem that streak-like scratches occur on the surface of the photosensitive layer due to the toner cleaning blade and paper due to the actual shooting. In addition, the commercial value of the photoreceptor is damaged because the photoreceptor is contaminated with toner, and inspection work is time-consuming because the photoreceptor must be attached to and removed from the copying machine.

[Purpose of the invention]

The present invention solves the above-mentioned problems with conventional inspection methods for the photosensitive layer of an electrophotographic photoreceptor, and automatically and reliably inspects the photosensitive layer without impairing the commercial value of the photoreceptor. It is an object of the present invention to provide an inspection device for an electrophotographic photoreceptor that can perform the inspection with high resolution.

[Key points of the invention]

In order to achieve the above-mentioned object, the present invention includes a charger that charges a photosensitive layer of an electrophotographic photoreceptor, a detection electrode arranged to face the photosensitive layer, and a detection electrode connected to the detection electrode. A field-effect transistor that outputs a signal according to the potential of a detection electrode constitutes an inspection device for an electrophotographic photoreceptor. With this configuration, it is possible to detect abnormal conditions in the photoreceptor's photosensitive layer. The amount of electrical charge in each part of the photosensitive layer changes, and the potential of the detection electrode changes due to electrostatic induction according to the amount of electrical charge. As a result, the photosensitive layer can be automatically and reliably inspected without damaging the commercial value of the photoreceptor. It is an object of the present invention to provide an inspection device that can perform this inspection and further perform this inspection with high resolution.

[Embodiments of the invention]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional side view of the electrostatic detector 6 in FIG. 1, and FIG. 3 is an electric circuit diagram of the detector 6 in FIG. 2. In FIGS. 1 to 3, 1 is an amorphous cylindrical body 1a with bottoms at both ends.
It is a photoreceptor, also called a photoreceptor drum, in which a photoconductor layer 1b of Te-containing Se or the like is formed as a photoreceptor layer by vapor deposition or the like, and the IC is the shaft of the photoreceptor 1 which is fixed and penetrated through the axis of the cylindrical body 1a. The shaft 1c is insulated from the ground 2 and rotatably supported by a bearing (not shown). A charger 3 is placed facing the photosensitive layer 1b and is configured to positively charge the photosensitive layer 2 by corona discharge; 4 is placed facing the photosensitive layer 1b and irradiates the photosensitive layer 1b. This is a static elimination lamp designed to eliminate the electric charge on the photosensitive layer. Charger 3 and lamp 4
are arranged in a direction symmetrical with respect to the axis IC.

The static eliminating lamp 4 may be replaced with electrical static eliminating means such as a slider. The photoreceptor 1 is configured to be rotated in the direction of arrow P around an axis IC by means not shown, and 5 is attached to the axis IC and rotates according to the rotation angle of the photoreceptor 1 from a reference position. This is a pulse encoder that outputs a signal. Reference numeral 6 denotes a cylindrical static electricity detector provided with a needle-shaped detection electrode 601 protruding from one end. At a position between the lamp 4 and the detection electrode 601, the detection electrode 601 is connected to the photosensitive layer 1b through the gap 7.
is placed so as to face the 8 is a support for supporting the detector 6; 9 is a shaft passing through the support 8;
The shaft 9 is supported by a mechanism not shown so as to be parallel to the shaft IC, and the detector 6 is configured to be moved along the shaft 9 by a mechanism not shown.

In other words, the detector 6 is configured so that the electrode 601 moves parallel to the axis IC while facing the photosensitive layer 1b. 10 is a pulse encoder that outputs a signal corresponding to the amount of translation of the detector 6 from the reference position.

6a and 6b are the power supply terminals of the detector 6, 6C is the output terminal,
In this case, the terminal 6a is connected to the positive side of the DC power source 11, and the terminal 6b is connected to the negative side of the power source 11 and also to the ground 2. 12 is terminal 6C and terminal 6
This is a data processing device which receives the output voltage E of the detector 6 outputted between
The configuration is such that each output signal of 0 is also input.

Rt, Ra, 1 (v are all fixed resistors, C1 is a capacitor, 603 is an MO8 type field effect transistor (
Below, this transistor is called MOS-11? (sometimes referred to as ET), these electronic components are connected to the detection electrode 60.
1 as shown in FIG. 3 and housed in a metal cylindrical body 602, both ends of the cylinder 602 are closed by insulating blocks 604 and 605, respectively. The detection electrode 601 is installed through the block 604 so that one end protrudes from one insulating block 604 and the other end is connected to the resistor and capacitor C1 within the cylindrical body 6026, and the power terminal 6a is connected to the insulating block 604. A resistor wire is connected to the power supply terminal 6b through the insulating block 605. The output terminal 6C passes through the insulating block 605 and is connected to the source S of the MOS-FET 603, and the cylindrical body 602 is electrically connected to the terminal 6b. 1
Reference numeral 3 denotes an inspection device for the photoconductor 1, which includes the above-mentioned parts except for the photoconductor 1.

Since the inspection device 13 is configured as described above, when the portion of the photosensitive layer 1b positively charged by the charger 3 rotates in the direction of the arrow P and comes to a position facing the detection electrode 601, A negative charge corresponding to the amount of charge in the photosensitive layer 1b is induced in the portion of the electrode 601 facing the photosensitive layer 1b by electrostatic induction, and as a result, the potential of the gate G of the FET 603 increases and the drain current of the FBT increases. As a result, the voltage drop across the resistor, in other words, the output voltage E of FET 603 appearing between terminal 6C and terminal 6b increases, and this voltage E corresponds to the potential fluctuation of gate 1-G. As is clear from the above-described mechanism, the voltage E varies depending on the amount of charge on the portion of the photosensitive layer 1b facing the detection electrode 601. If the photosensitive layer 1b has abnormal parts such as peeling, scratches, and dents, white spots will occur due to such parts, and this is because the conductivity of the photosensitive layer 1b becomes better in the abnormal parts as described above. The inventor has confirmed through experiments that this is because even if an attempt is made to charge the photosensitive layer 1b with a charge using a discharge means, the amount of charge is almost not charged or the amount of charge is small. , if there are abnormal parts such as peeling, scratches, dents, etc. on the photosensitive layer 1b,
When this portion faces the detection electrode 601, the amount of charge charged in the abnormal portion is small, so the output voltage E decreases compared to when the amount of charge charged is large.

In FIG. 1, as described above, the photoreceptor 1 is rotated in the direction of the arrow P, and the electrostatic detector 6 is configured to be moved parallel to the photoreceptor 1. Since the inspection device 13 is configured to perform this rotational movement and parallel movement at the same time, the detection electrode 601 charges the photosensitive layer 1b charged by the charger 3, as shown in FIG. The entire surface of the photosensitive layer 1b is scanned along the scanning line indicated by Q, and as a result, the output voltage E shows a time course as shown in FIG. 5, for example. In FIG. 4, the arrow R indicates the direction of movement of the detector 6 with respect to the photoreceptor 1, and in FIG. There is. The voltage change 14 is caused by the photosensitive layer 1
The voltage E is decreasing due to the small amount of charge in the abnormal part in b, and three voltage changes 14 appear in FIG. 5, which are shown in a wedge shape in FIG. This is the result of scanning the abnormal area 15 three times with the detection electrode 601 shown in FIG. 1 because the abnormal area 15 in the photosensitive layer 1b is quite wide. Therefore, if the output voltage E in FIG. 1 changes as shown in FIG. The degree of abnormality in the portion 15 is estimated. 1st
The data processing device 12 shown in the figure detects the voltage change 14 and detects the abnormal portion 1 that caused the voltage change.
5 and the extent of the abnormality, and also determine the position of the abnormal portion 15 on the photoreceptor 1 based on the output signals of the encoders 5 and 10.

According to the inspection device 13 of FIG. 1, each part is configured as described above, so that the data processing device 12 can inspect the photoconductor photosensitive layer 1b without mounting the photoconductor 1 in a copying machine or the like. This is done automatically and reliably, and the detection electrode 6
Since 01 is needle-shaped, it is clear that the inspection is performed with high resolution.

Although it is preferable that the size of the gap 7 in the inspection device 13 is as small as possible, the inventor has determined that a size of about o, i to 1 [home] is appropriate considering the dimensional accuracy of each related part. found experimentally. Furthermore, the resistor A in FIG. 3 is provided to prevent the MOS-FET 603 from being destroyed by the charged charge of =10- in the photosensitive layer if the detection electrode 601 comes into contact with the photosensitive layer 1b. , the capacitor C1 in the same figure has become larger due to the provision of a resistor element. This is provided to improve the response delay of the FET 603. In the above embodiment, the detection electrode 601 is needle-shaped and the FET 603 is MOS type, but it is obvious that the former may be rod-shaped and the latter may be bonded.

〔Effect of the invention〕

As described above, the present invention includes a charger for charging a photosensitive layer of an electrophotographic photoreceptor, a detection electrode arranged to face the photosensitive layer, and a detection electrode connected to the detection electrode. A field-effect transistor that outputs a signal according to the potential of To automatically and reliably inspect a photosensitive layer without impairing the commercial value of a photoreceptor, as a result of changing the amount of charged charge in the photoreceptor and changing the potential of a detection electrode due to electrostatic induction in accordance with the amount of charged charge. This has the effect of providing an electrophotographic photoreceptor inspection apparatus that can roughly conduct this inspection with high resolution.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a longitudinal cross-sectional side view of the electrostatic detector shown in Fig. 1, and Fig. 3 is a sectional view of the electrostatic detector shown in Fig. The circuit diagram, FIG. 4 is a side view for explaining the operation of the main part of the inspection apparatus of FIG. 1, and FIG. 5 is an explanatory diagram of the output voltage E in FIG. 1. 1... Photoreceptor, 1b... Photosensitive layer, 3... Fluorescent device, 1
3... Inspection device for electrophotographic photoreceptor, 601... Detection electrode, 603... Field effect transistor, E... Output voltage. eagle

Claims (1)

[Claims] A charger that charges a photosensitive layer of an electrophotographic photoreceptor, a detection electrode arranged to face the photosensitive layer, and an electric field to which the detection electrode is connected and outputs a signal according to the potential of the detection electrode. 1. An inspection apparatus for an electrophotographic photoreceptor, comprising: an effect transistor, and the photosensitive layer is inspected using an output signal of the field effect transistor.