JPS63200178A - Flaw inspection device for photosensitive body - Google Patents

Abstract

PURPOSE:To measure and inspect the minute area unit of the surface of a photosensitive body by electrifying the surface of the photosensitive body with the electric charge while interrupting the light and projecting a beam which has the prescribed quantity of light and has a minute diameter thereafter to detect the flaw of the photosensitive body in accordance with the current change accompanied with the migration of the electrification electric charge at the time of photoirradiation. CONSTITUTION:After the surface of a photosensitive body 1 is electrified with the electric charge in a dark place, an inspection luminous flux 9a is projected. The radiated part of the photosensitive body 1 reacts on the light and the resistance value of this part is reduced, and the state between the surface of the photosensitive body 1 and a conductive cylinder tube 2 approximates the conductive state, and electrons are so migrated that the electric charge on the surface of the photosensitive body 1 is equalized to the potential of an earth 19 through the conductive cylinder tube 2, a signal line 20, and a current detecting part 22. The quantity of these electrons is proportional to the quantity of electric charge electrified on the surface of the photodetector 1, and this migration of electrons, namely, the current is detected by the current detecting part 22 to find the electrified state of the electric charge, namely, the presence or the absence of the flaw on the surface of the photosensitive body 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention eliminates defects such as scratches, pinholes, thickness unevenness, and foreign matter contamination in the photoreceptor portion of photoreceptor drums used in copying machines and the like. The present invention relates to a photoconductor defect inspection device for detecting defects.

(Prior Art and Problems to be Solved by the Invention) Conventionally, the surface of the photoreceptor, including defects and performance, was charged and the state of charge distribution was measured using a surface electrometer. The potential measurement sensor's aperture size was limited, making it impossible to measure in minute area units.

Furthermore, this conventional example has problems such as variations in the measured values due to variations in the distance (interval) between the surface of the photoreceptor and a portion of the seven punches.

On the other hand, there is a method of actually printing an image using toner and visually inspecting the printed image to detect defects in the photoreceptor, but this contaminates the photoreceptor and the inside of the device, and the toner and
There is a problem that transfer paper is wasted. There is also a method of capturing an image of the photoreceptor drum surface with a television camera and detecting defects through image processing, but there is a problem in that it is difficult to detect defects such as thickness unevenness and pinholes.

Therefore, the present invention has been made to solve the above-mentioned problems of the conventional example, and its purpose is to measure the minute area unit of the surface of the photoreceptor without wasting the color of toner, transfer paper, etc. An object of the present invention is to provide a photoconductor defect inspection device that enables inspection.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a charging means for charging the surface of a photoreceptor with an electric charge while blocking light, and a charging means for charging the surface of the photoreceptor, and the photoreceptor charged by the charging means. An optical system for irradiating a body surface with light of a predetermined amount and a minute diameter, and a detection means for detecting a change in current accompanying movement of the charged charge on the photoreceptor during irradiation with light, It is configured by detecting defects in the photoreceptor.

(Function) In the present invention having the above configuration, after the surface of the photoreceptor is shielded from light and charged with an electric charge by the charging means.

A predetermined amount of light with a minute diameter is irradiated by an optical system, a detection means detects a current change due to the movement of charged charges during light irradiation, and defects in the photoreceptor are detected from this current change. to be inspected.

(Example) The present invention will be explained below based on the illustrated example. 1st
The figure shows an embodiment of the photoconductor defect detection device according to the present invention. A charging roller as a charging means for charging the surface of the photoreceptor 1; 4 an air cylinder for pressing the charging roller 3 against the photoreceptor 1 when charging the surface of the photoreceptor 1; 5 the charging roller 3 and the air cylinder an insulating material plate that electrically insulates 4;
6 is a charging power source, and one output end 21 is connected to the charging roller 3. Reference numeral 7 denotes a light source for charge removal, which forcibly removes charges on the surface of the photoreceptor 1.

8 is an optical filter that removes static electricity by irradiating the photoreceptor l with light that does not have an adverse effect; 9 is a light source for inspection such as a laser; 9
a is an inspection light beam output from the inspection light source 9; 10 is an ND filter for varying the amount of light of the light beam 9a; 11
is a beam expander, lla is a pinhole that determines the diameter of the beam irradiated onto the surface of the photoconductor 1, and 12 is a shutter that irradiates or blocks the inspection light beam 9a emitted from the inspection light source 9 onto the photoconductor l. I do things. This shutter 12 is driven by a motor 13.

Reference numeral 14 denotes a mirror that changes the optical path of the light from the inspection light source 9 that has passed through the shutter 12, and is configured integrally with the galvanometer 15. By operating the galvanometer 15,
The mirror 14 is rotated in the direction of the arrow θ to scan the inspection light beam 9a back and forth in the longitudinal direction of the conductive cylindrical tube 2. 16 directs the inspection light beam 9a onto the surface of the photoreceptor l! This is a lens for forming an image and scanning at a constant speed.

Reference numeral 17 denotes a changeover switch. When the surface of the photoreceptor 1 is charged by the charging roller 3, turning it ON (closed) causes the air cylinder 4 to operate and transfer the charging roller 3 to the photoreceptor 1.
This will lead to pressure on

The conductive cylindrical tube 2 and the ground terminal 18 of the charging power source 6 are connected to each other by a changeover switch 17. They are connected via a signal line 20, whereby the output voltage of the charging power source 6 is applied between the photoreceptor 1 and the conductive cylindrical tube 2 via the charging roller 3, thereby enabling charging. On the other hand, when the changeover switch 17 is set to oFp (fl), the ground terminal 18 side of the charging power source 6 is disconnected from the conductive cylindrical tube 2, and at the same time, the air cylinder 4 is operated to separate the charging roller 3 from the photoreceptor l. This makes it impossible to charge.

Reference numeral 22 denotes a current detection unit as a detection means, which detects current changes caused by the movement of charges when the surface of the photoreceptor 1 is irradiated with the inspection light beam 9a after charging the surface of the photoreceptor 1. Detection is made between the signal line 20 connected to the ground (2) and the ground (9). 23 is an output signal of the current detection section 22, and a signal obtained by converting a current into a voltage is output. 24 is the current detection section 2
This is a defect determining section which receives the output signal 23 of No. 2 and determines a defect in the photoreceptor 1 from the magnitude of the voltage value corresponding to the detected current. Reference numeral 25 denotes an output signal from the defect determination section 24, which sends out the output signal when it is determined that there is a defect.

Reference numeral 26 denotes an external light shielding cover as a light shielding member for preventing external light from irradiating the photoreceptor l, which is the object to be inspected, and the inspection is performed in a dark place.

In the above configuration, defects in the photoreceptor 1 are inspected as follows. First, the shutter 12 is driven by the motor 13 to a position where it blocks the inspection light beam 9a.Next, the static elimination light $7 is turned on, and at the same time, the conductive cylindrical tube 2 is rotated at a predetermined number of rotations to remove the conductive The entire surface of the photoreceptor 1 coated on the cylindrical tube 2 is irradiated with static eliminating light, and the photoreceptor 1 is
erases the charge on the surface of Then, when the entire surface of the photoreceptor 1 is irradiated with light for charge removal for a certain period of time, the light source 7 for charge removal is turned off, and then the entire surface of the photoreceptor 1 is charged with a fixed amount of charge. For this purpose, by turning on (closed) the changeover switch 17, the air cylinder 4 is operated, and the charging roller 3 is pressed against the photoreceptor 1 with a constant load. At the same time, the charging power source 6 is turned on, and the output voltage of the charging power source 6 is applied between the photoreceptor 1 and the conductive cylindrical tube 2, so that the surface of the photoreceptor 1 is charged. Incidentally, since the conductive cylindrical tube 2 is rotating at a constant rotation speed, the charging roller 3 on the entire surface of the photoreceptor IQ comes into rotational contact with a constant load, and charging is performed.

Here, the amount of charge is determined by the output voltage value of the charging power source 6 and the time during which the charging roller 3 is in contact with the charging roller 3 or the number of rotations of the conductive cylindrical tube 2. The amount of charge is determined by the number of rotations of the charging roller 3 of the cylindrical tube 2 after contact. That is, the number of rotations of the conductive cylindrical tube 2 after the changeover switch 17 is turned ON (closed) is detected by a rotation detector, etc., and when the set number of rotations is reached, the changeover switch is turned OFF (opened) to complete charging. do. Note that by turning the changeover switch 17 OFF (open), the air cylinder 4 is operated, and the charging roller 3 is separated from the surface of the photoreceptor l. By charging the photoreceptor 1 in this way, a predetermined amount of charge is charged on the surface of the photoreceptor 1, but if there is a difference in the resistance value of the photoreceptor 1 in the dark, that part will be different from others. In comparison, there is a difference in the amount of charge. That is, when the resistance value is high, the amount of charge is large, and when the resistance value is low, the amount of charge is small.

Further, the charging roller 3 has a certain degree of elasticity so as to be able to cope with large warping of the conductive cylindrical tube 2.
For local surface irregularities.

There may be some areas where the charging roller 3 is not completely contacted, and in this case as well, there will be a difference in the amount of charge compared to other areas.

-Next, after charging, the motor 13 is activated and the shutter 12 is placed in a position where the light beam emitted from the inspection light source 9 passes. The light beam that has passed through the shutter 12 is irradiated onto the surface of the photoreceptor l via the mirror 14 with a certain amount of light and a determined light beam diameter. If the galvanometer 15 is operated, the position of the mirror 14 changes, and the inspection light beam 9a is irradiated back and forth along the longitudinal direction of the conductive cylindrical tube 2. Furthermore, since the conductive cylindrical tube 2 rotates at a constant speed, the entire surface of the photoreceptor 1 can be irradiated with a certain amount of light and a predetermined luminous flux diameter.

In this case, it is assumed that the part that has been irradiated once will not be irradiated again.

In this way, after the entire surface of the photoreceptor 1 is sequentially irradiated with a certain amount of light and a predetermined beam diameter.

The inspection is completed by activating the motor 13 and setting the shutter 12 to a position that blocks the output beam of light from the inspection light source 9 so as not to irradiate the inspection light beam 9a onto the surface of the photoreceptor 1. still,
In case of re-inspection.

The above operation will be repeated.

As described above, by irradiating the inspection light beam 9a after charging the surface of the photoreceptor 1 in a dark place, the irradiated portion of the photoreceptor l reacts to the light and its resistance value decreases. body 1
The surface and the conductive cylindrical tube 2 are almost in a conductive state, and the charges on the irradiated surface of the photoreceptor 1 are transferred to the conductive cylindrical tube 2, the signal line 20 connected to the conductive cylindrical tube 2, and further During this time, movement of electrons that passes through the current detection section 22 and becomes equal to the potential of the ground 19 occurs. In other words, the amount of electrons is proportional to the amount of charge charged on the surface of the photoreceptor 1, and as mentioned above, if the photoreceptor 1 is in a dark place and there is a difference in resistance value,
In addition, differences in the amount of charge occur due to surface irregularities, etc., and when a part in such a state is irradiated with the inspection light beam 9a, the amount of electrons moves according to the amount of charge, and this amount of electrons changes. By detecting the movement of the photoreceptor 1, that is, the current, by the current detection unit 22, it is possible to determine the charging state of the surface of the photoreceptor 1, that is, whether there is a defect. Note that in the case of a normal photoconductor with a uniform charging state, when the surface is sequentially irradiated with the inspection light beam 9a, the output signal 23 of the current detection section 22 has a voltage corresponding to the amount of charged charge, i.e. A constant voltage is output each time the entire photoreceptor surface is sequentially irradiated once. In this way, the output signal 23 is outputted to the defect determination section 24 as a voltage value corresponding to the current value detected by the current detection section 22.

By the way, in the defect determination section 24, the current detection section 2 is connected to the upper limit standard comparator 27 and the lower limit standard comparator 28 as shown in FIG.
The output signals 23 of the comparators 27 .
Standard value of 28 is 27'.

28', and if it is greater than the upper limit specification value 27', a signal indicating a defect is output to the signal line 29, and if the lower limit specification value 28
If the value is less than ', a signal indicating a defect is output to the signal line 30. These signal lines 29, 30 are connected to the OR gate 31 and the upper limit.

If either of the lower limits is exceeded, a defect signal is output to the output line 32 of the OR gate 31. This output signal is connected to one side of the two-manual AND gate 33, and the other signal 34 is a signal while the shutter 12 is open, that is, a signal while the surface of the photoreceptor 1 is irradiated with the inspection light beam 9a. If a defect signal is output during this period, the defect signal is output to the output signal 25 of the AND gate 33.

Here, the upper limit and lower limit standard values are assumed to be variable depending on the amount of charge, the light amount of the inspection luminous flux 9a, and the like.

In the above embodiment, the charging roller 3, air cylinder 4, and insulating plate 5 of the charging mechanism can also be used as a charging device using corona discharge, which is used in a copying machine, so that the charging roller 3, the air cylinder 4, and the insulating plate 5 can be used as a charging device using corona discharge. Charging and inspection are possible without having to do so. In addition, a mirror 14 and a galvanometer 15
functions similarly even if changed to a polygon mirror.

Furthermore, in the above embodiment, it is possible to measure the responsiveness of the photoreceptor 1 to light irradiation. That is, after charging, the photoreceptor 1
Responsiveness can also be measured by passing through the shutter 12 the inspection light beam 9a for a predetermined time, that is, by irradiating the photoconductor 1, and outputting the output signal 23 of the current detection unit 22 to a recorder or the like at this time. becomes. Also, as shown in Fig. 4, the time Tl
tT2. Responsiveness can also be tested by measuring T3 and peak output value V.

Furthermore, in the above embodiment, the light intensity of the light emitted from the inspection light source 9 is gradually reduced using the ND filter 10, and the output of the current detection unit 22 at each light intensity value is measured to determine the output relative to the light intensity. By graphing the measured values, it is possible to know the sensitivity characteristics with respect to the amount of light. however,
To check the characteristics of a part that has been irradiated with a certain amount of light, that is, at the same location, after irradiation, the static elimination light source 7 is turned on again, then it is charged, and the operation of irradiating and measuring with a different amount of light is repeated. It turns out. Incidentally, if the irradiation does not have to be at the same location, measurement can be performed by changing the irradiation location and changing the light intensity.

In the above embodiment, by changing the wavelength of the output light of the inspection light source 9 and irradiating it onto the charged photoreceptor 1, and measuring the output of the current detection section 22 at that time, the sensitivity characteristics with respect to the light wavelength can be determined. You can know.

(Effects of the Invention) The photoconductor defect inspection device according to the present invention has the above-described configuration and operation, and since the light that irradiates the charged state of the photoconductor surface has a predetermined amount and a minute diameter, it As a result, it has become possible to measure and inspect on a fine area unit (high resolution) compared to commercially available surface electrometers. Further, since defects in the photoreceptor are not detected by image printing, toner, transfer paper, etc. are not consumed, and economical efficiency can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of a photoreceptor defect inspection device according to the present invention, FIG. 2 is a circuit diagram of a defect determination section in the same embodiment, and FIG. 3 is a signal diagram of each part in the same embodiment. FIG. 4 is a time chart showing an example of testing the responsiveness of the photoreceptor to light irradiation in the same embodiment. Explanation of symbols 1... Photoreceptor 2... Conductive cylindrical tube 3.
...Charging roller (charging means) 7...Light source for static elimination 9...Light source for inspection 12.
... Shutter 14 ... Mirror 15 ... Galvanometer 17 ... Changeover switch 22 ... Current detection section (detection means) 24 ... Defect determination section Fig. 1

Claims (1)

[Claims] a charging means for charging the surface of a photoreceptor by shielding it from light; an optical system for irradiating a predetermined amount of light and a minute diameter onto the surface of the photoreceptor charged by the charging means; and the photoreceptor at the time of light irradiation. 1. A photoconductor defect inspection apparatus, comprising: a detecting means for detecting a current change due to movement of charged charges; and detecting a defect in the photoconductor based on the current change.