JPS62189477A - Method for inspecting electrophotographic sensitive body and apparatus used in said inspection method - Google Patents

Abstract

PURPOSE:To enable easy discrimination of whether a defect exists or does not exist by cleaning the remaining toner on the surface of an amorphous silicon photosensitive body and impressing a high voltage thereto in contact therewith, then irradiating light to erase the memory, forming a transferred image on a material to be recorded and inspecting the transferred image. CONSTITUTION:The remaining toner on the photosensitive drum surface 1 after the process for forming an electrophotographic image is removed by a cleaning means 3 and the high voltage is impressed to the drum surface 1 by a conductive rubber roller 5 connected to a constant voltage power source 6. The photosensitive drum 1 is exposed again by an exposing means 4 to erase the residual potential. The spherical projections which are problematic on the a-Si photosensitive drum 1 surely develop the image defect to a sensible image in an image forming stage. The image having the image defect is formed if such electrophotographic image is formed. The photosensitive drum having the defect is thereby surely expelled prior to delivery.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to amorphous silicon (hereinafter referred to as
(abbreviated as a-5i) A method for inspecting latent defects on a photoreceptor and an apparatus used in the inspection method, more specifically, the following describes an image defect that occurs due to a spherical protrusion on the surface of the a-5i photoreceptor. The present invention relates to a method for inspecting defects on a photoreceptor by exposing them in advance during inspection of the photoreceptor, and an apparatus used in the inspection method.

[Prior Art] Currently, the A-5I photoreceptor drum for electrophotography generally uses plasma discharge to decompose silane gas mixed with hydrogen and various doping gases, and then applies the A-5I to the heated metal drum 1.
It is manufactured by a plasma CVD method that forms a 5i deposited film. In this manufacturing method, the deposition on the drum 1
Powder that does not contribute to the formation of anti-fouling particles is inevitably generated. If such powder, chips from cutting the drum, and even various types of dust adhere to the drum during the formation of the a-5L deposition film,
These may act as a nucleus, causing abnormal growth of the a-5i deposition nq into a partially spherical shape. This a-5i deck'1ll
The spherical abnormal growth in Q is generally called a spherical protrusion.

Image defects in electrophotographic images using a-5iFA light body,
Most of this is caused by these spherical protrusions, and photosensitive drums are manufactured under conditions in which such powder, dust, etc. are excluded to a level that is acceptable in terms of image quality for electrophotography.

In order to form good images from the initial stage of use as a photoreceptor for electrophotography, it is necessary to detect defects in the photoreceptor in advance to prevent defective photoreceptors from being installed in electrophotographic equipment.
It is necessary to F. However, even after inspection, the reality is that spherical protrusions remain in a small number of photoreceptors. These spherical protrusions generally cause a decrease in resistance or dielectric breakdown as the photoreceptor continues to be used, resulting in image defects A and B on halftone images.
to occur. Here, image defect A refers to O
, INl, 5mmφ white spots (hereinafter referred to as white spots) and black spots (hereinafter referred to as black spots) on a full-white copy during reversal development. Both are essentially the same in that this is a part with low resistance and the potential is lower than other parts. In addition, image defect B is a white spot with a black shadow on a halftone image in normal development and a white spot around a black spot on a halftone image in reverse development, and both of these are caused by differences in the development method. They are essentially the same thing.

The growth mechanism of image defects is that the spherical protrusions that cause image defects have a lower resistance than other parts, so current flows in a concentrated manner, damaging the spherical protrusions (
In most cases, this results in image defect B), and in other cases, dielectric breakdown easily occurs due to the low withstand voltage of the spherical protrusion (in most cases, image defect A occurs). When the spherical protrusion undergoes dielectric breakdown, the image defect A becomes large, and when the spherical protrusion with a diameter of 30 to 50 μΦ is damaged by concentrated electric charge, there is a high probability that the image defect A will become the image defect B.

The reason why the white spot has a shadow is thought to be that when the potential of the white spot is Ov as shown in FIG. 2, the potential of the surrounding area is higher than that of the normal area. In other words, since the spherical protrusion that causes the image defect B has low resistance, the current tends to decrease;
In addition, as the photoreceptor rotates, it is charged by corona discharge from the charging wire, so the current begins to concentrate before the spherical protrusion comes directly under the charging wire, and even when it passes directly under the charging wire, it is opposite to when it approaches. The current attenuates in the following manner. Therefore, the discharge current, which normally concentrates most strongly directly under the charging wire, is partially concentrated on the spherical protrusion as it passes through the spherical protrusion. A potential state as shown in the figure is formed, resulting in an image defect B on the transferred image.

Image defect B is a defect that is very noticeable especially when it appears in a halftone copy image, and is a defect that significantly impairs image quality. It's deadly. The photoreceptor, which was at an acceptable level during the first few days of use,
It is difficult to tell from the condition of the photoreceptor immediately after manufacture that the photoreceptor develops image defect B as time passes, so quality control of the a-5i photoreceptor is carried out. It was a big obstacle at the top.

[Problem that the invention seeks to solve]

In view of the above points, the present invention has latent features in the a-5i sense nine body,
Detects spherical protrusions that cause large black spots and shadowed white spots, and selects photoconductors that develop image defects due to spherical protrusions over time after use, enabling more accurate photoconductor quality control. It is an object of the present invention to provide a method for inspecting defects in an A-5I sensor and an inspection apparatus suitable for use in the inspection method.

Another object of the present invention is to provide an inspection apparatus having a configuration similar to an electrophotographic apparatus, in which an A-5T photoreceptor is actually mounted before being inspected, an image is formed, and the obtained image is inspected. It is an object of the present invention to provide a photoconductor inspection device in which the presence or absence of defects can be easily determined, the photoconductors are not sorted out more than necessary, inspection operations are simple, and inspection work can be performed quickly.

[Means for solving problems]

That is, the method of inspecting latent defects in an electrophotographic photoreceptor of the present invention involves cleaning residual toner on the surface of an amorphous silicon photoreceptor, applying a high voltage to the surface of the photoreceptor, and then inspecting the surface of the amorphous silicon photoreceptor. Following the light irradiation process for erasing the memory of the photoreceptor, a transferred image is formed on a recording material by an electrophotographic image forming process, and the transferred image is inspected.

Furthermore, the electrophotographic photoreceptor inspection apparatus of the present invention includes a means for installing an amorphous silicon photoreceptor to be inspected, a cleaning means for cleaning residual toner on the surface of the photoreceptor, and a means for erasing the memory on the photoreceptor. An apparatus comprising at least a pre-exposure means for irradiating a photoreceptor with light for cleaning, and an electrophotographic image forming means, the cleaning means including a conductive rubber roller for applying a high voltage onto the surface of the photoreceptor. It is characterized in that it is disposed at an intermediate location between the pre-exposure means and the pre-exposure means.

[Preferred embodiment for carrying out the invention] FIG. 1 is a schematic diagram illustrating one embodiment of an inspection apparatus suitable for use in the method of inspecting defects in a photoreceptor drum for electrophotography according to the present invention. , the inspection apparatus of the present invention basically includes a means 2 for installing an A-5I photosensitive drum 1 to be inspected;
A cleaning means 3, a pre-exposure means 4, a conductive rubber roller 5, a constant voltage electric current 6 for applying a high voltage to the conductive rubber roller 5, an electrostatic latent image forming means, a toner supply means, and a recording material. and an image forming means including a transfer means and the like.

The amorphous silicon photoreceptor to be inspected according to the present invention has a photoreceptor whose surface is made of an amorphous material containing silicon atoms, and is usually made of a photoreceptor layer on a support such as a metal. It has a drum-like shape.

In the inspection method of the present invention, the a-5i photoconductor drum l to be inspected mounted on the photoconductor drum installation means 2 is
After being exposed by the pre-exposure means 4 and erasing the memory of the photoreceptor drum 5, after going through an electrophotographic image forming process,
The residual toner on the surface of the photoreceptor drum is removed from the surface of the photoreceptor drum 1 by the cleaning means 3. The photosensitive drum that has passed through this cleaning means 3! A high voltage is applied to the surface of the photoreceptor drum by contact applying means for applying high voltage to the surface of the photoreceptor drum, for example, a conductive rubber roller 5 connected to a constant voltage power source 6. Next, the photoreceptor drum 1 is exposed again by the pre-exposure means 4, the residual potential is erased, and the process proceeds to the image forming process again.

As the electrophotographic image forming process (means) used in the method and apparatus of the present invention, various conventionally known processes can be employed, and any process may be used. Typical examples include, for example, U.S. Patent No. 2,860,048, Japanese Patent Publication No.
Publication No. 16429, Japanese Patent Publication No. 38-15446,
Special Publication No. 46-3713, Publication No. 42-23910
Publication No. 43-24748, Special Publication No. 42-
It is described in Japanese Patent Publication No. 19747, Japanese Patent Publication No. 36-412147, etc.

A conductive rubber roller 5 is suitable as the high voltage contact application means, and a typical conductive rubber roller is one formed by filling and mixing conductive particles into an elastic polymer. Conductive particles include stainless steel, copper, silver,
Examples include metals such as iron and carbon black, and carbon black is preferably used. Further, typical examples of elastic polymers include silicone rubber, urethane rubber, butadiene rubber, isoprene rubber, nitrile rubber, and natural rubber.

The conductive rubber roller 5 has a diameter of 30 to 60 mmφ.
, surface hardness based on JIS 63 old is 10~30°,
A suitable material has a volume resistivity of 10 to 10×7 Ω and a nip width of about 6 to h+m with respect to the photosensitive drum to be inspected.

The conductive rubber roller 5 has a constant voltage of 300~
A voltage of 600 V is applied, and this voltage is applied in contact with the surface of the photosensitive drum 1 to be inspected. At this time, the spherical protrusions that cannot withstand the voltage applied by the rubber roller 5 cause dielectric breakdown. Since the application of high voltage by the conductive rubber roller 5 is not corona charging but contact voltage application, dielectric breakdown occurs even in low-resistance spherical protrusions that simply have poor charging ability in corona charging. If the voltage applied by the high voltage contact application means is too low, dielectric breakdown will not occur in the spherical protrusions inherent in the photoreceptor drum, and the method of the present invention cannot be carried out effectively. On the other hand, if the voltage is too high, even normal spherical protrusions that do not cause image defects in normal electrophotographic image forming processes will be dielectrically broken down and image defects will occur. It gives results that are not in accordance with the purpose.

When subjected to such high voltage application processing, the problematic spherical protrusions on the a-5i photosensitive drum 1 will certainly cause image defects in the 5th image forming process.

In other words, even if there is a spherical protrusion on the photoreceptor drum that cannot be detected by conventional inspection and gradually causes image defects with use, the above voltage cannot be applied to such spherical protrusion. This will definitely cause dielectric breakdown. Therefore, when an electrophotographic image is formed by the inspection method of the present invention, an image with image defects will be formed on the photoreceptor drum, which gradually develops image defects with use.
It becomes possible to reliably eliminate photosensitive drums having defects before shipping.

(Effects of the Invention) By carrying out the inspection of a-5i bad sensitivity light using the inspection method of the present invention, it is possible to force the production of a-5i!f3. It has become possible to develop and inspect image defects in electrophotographic devices, and it has become possible to suppress the appearance of image defects in commercialized electrophotographic devices as much as possible.In addition, it has become possible to accurately control the quality of A-5I bad exposure. By feeding back this information, it has become possible to reduce the occurrence of defective photoreceptors in the production of a-Si photoreceptors.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram illustrating an embodiment of an apparatus for inspecting defects on a photoreceptor for electrophotography according to the present invention, and FIG.
5 is a diagram for explaining the principle of image defects appearing in electrophotography due to spherical protrusions on the surface of a 5i photoreceptor. FIG. 1: A-5i photosensitive drum for inspection 2: Installation means for photosensitive drum

Claims (1)

[Scope of Claims] 1) After cleaning residual toner on the surface of an amorphous silicon photoreceptor, a high voltage is contact-applied to the surface of the photoreceptor, and then a light irradiation process for erasing the memory of the photoreceptor. Subsequently, a transferred image is formed on a recording material by an electrophotographic image forming process, and the transferred image is inspected for latent defects in the photoreceptor drum. 2) The method according to claim 1, wherein a high voltage of 300 to 600 V is applied by bringing a conductive rubber roller into contact with the surface of the photoreceptor. 3) means for installing an amorphous silicon photoreceptor to be inspected, a cleaning means for cleaning residual toner on the surface of the photoreceptor, and a pre-exposure means for irradiating the photoreceptor with light for erasing the memory on the photoreceptor; An apparatus comprising at least an electrophotographic image forming means, wherein a conductive rubber roller for applying a high voltage onto the surface of the photoreceptor is disposed at an intermediate position between the cleaning means and the pre-exposure means. An inspection device for an electrophotographic photoreceptor, which is characterized by: