JPH03280063A - Positioning device for photosensitive drum - Google Patents

Abstract

PURPOSE:To accurately position a drum without scratching the drum, to prevent irregularities in application and to keep the used amount of fluid from increasing by disposing a ring-like pressurizing cylinder which uniformly blows the fluid against the outer peripheral surface of the drum with discharge pressure from entire outside circumference coaxially to the drum. CONSTITUTION:At the position of the cylindrical drum 1 where coating liquid is not applied yet or where it is already applied, the ring-like pressurizing cylinder 3 which uniformly blows out the fluid against the outer peripheral surface of the drum with the discharge pressure from the entire outside circumference is disposed coaxially to the drum 1, and the length of the pressurizing cylinder 3 on the drum 1 side in an axial direction is >=50mm. For example, by blowing out air from the circumference of the drum 1, the position of the drum 1 is neutralized by the blow-out pressure and the drum 1 is located at a specified position. Since the mechanical contact to the drum 1 is prevented, the drum 1 is not scratched. Then, the increase of the used amount of the fluid is evaded because air amount used enough to obtain uniform pressure is little.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for positioning a cylindrical drum when manufacturing an electrophotographic photoreceptor by applying a photosensitive liquid to the cylindrical drum.

[Conventional technology]

In manufacturing an organic photoconductor photosensitive drum, which is a photosensitive member used in an electrophotographic apparatus, a photosensitive coating liquid is applied to a cylindrical drum. For application, a slide hopper is positioned at a predetermined position around the cylindrical drum,
Adjustment work is required to maintain a constant clearance between the two in the circumferential direction. In this case, since the required thickness of the coating layer is extremely thin, even if the cylindrical drum shifts by 0.1 mm, it will cause a large deviation in the thickness of the coating layer as a whole in the circumferential direction.

It is a well-known fact that such deviations in the thickness of the coating layer cause various problems such as changes in the amount of charge, non-uniform sensitivity, and changes in residual potential in the circumferential direction of the cylindrical drum. Accurate positioning of the cylindrical drum is therefore extremely important.

Conventionally, this type of drum positioning device includes a position regulating roller rotatably provided on a support member and in contact with the outer periphery of the drum, as described in Japanese Patent Application Laid-Open No. 60-50537. It is.

[Problem to be solved by the invention]

However, in this type of conventional device, the positioning roller is placed in direct contact with the drum for positioning, so there is a problem in that the drum may be damaged. It is well known that electrophotographic properties deteriorate if the drum is scratched.

Therefore, when positioning the drum, the present inventors decided to perform the positioning by, for example, blowing air.
It has been found that this method is extremely effective in preventing scratches on the drum.

However, as shown in FIG. 7, when the photosensitive liquid is applied from the coating head 2 while the drums 1 are successively connected and moved, the photosensitive liquid is applied from each air blowing nozzle 10 arranged horizontally at three locations in the circumferential direction. When positioning the drum 1 using the air pressure of It may come out upwards. In this case, coating defects such as horizontal unevenness and lack of photosensitive liquid occur.

Furthermore, unless a large amount of air is blown out, it is difficult to position the drum 1, leading to an increase in production costs.

Therefore, the main object of the present invention is to accurately position the drum without damaging the drum, to prevent uneven coating, and to avoid increasing the amount of fluid used.

[Means to solve the problem]

The above-mentioned problem is a device for positioning the drum when manufacturing a photosensitive drum, surrounding the outer circumferential surface of the cylindrical drum, and applying a coating liquid to the outer circumferential surface from a coating head; Alternatively, at the position where the coating liquid has been applied, a ring-shaped pressure cylinder is disposed coaxially with the drum, and the pressure cylinder is arranged coaxially with the drum, and the pressure cylinder is disposed on the same axis as the drum, and the pressure cylinder is disposed on the same axis of the drum, and the pressure cylinder is disposed on the same axis as the drum. This problem can be solved by having a length in the direction of 50 mm or more.

[For production]

In the present invention, the cylindrical drum is positioned by blowing fluid against its outer peripheral surface and using the fluid pressure. That is,
When fluid, such as air, is blown out from around the drum, the pressure of the blown air neutralizes the position of the drum, thereby allowing the drum to be positioned at a predetermined position.

Moreover, since there is no mechanical contact with the drum, damage to the drum can be prevented.

On the other hand, since a ring-shaped pressurizing cylinder that blows fluid against the drum's outer peripheral surface with uniform discharge pressure from the entire outer periphery is disposed coaxially with the drum, when the blowing pressure is lowered, the inner surface of the pressurizing cylinder and the drum A static pressure chamber can be formed between the outer surface and the outer surface. When this static pressure chamber is formed, if an external force is applied that shifts the center axis of the drum and the pressure in the circumferential direction of the static pressure chamber becomes unbalanced, an attempt is made to resolve this and equalize the pressure. As a result, the center axis of the drum is prevented from shifting.

Therefore, since the amount of air used to equalize the pressure is very small, the power cost of the compressor can be reduced.

〔Example〕

The present invention will be explained in more detail below with reference to Examples.

FIG. 1 shows a first embodiment, in which 1 is a hollow cylindrical drum, for example, and the bottom surface of the drum is raised by a conveying means (not shown) such as a cylinder, or alternately gripped by appropriate gripping means. This causes it to rise continuously.

Reference numeral 2 denotes an annular coating head for applying photosensitive liquid to the outer peripheral surface of the drum 1, which is fixed to the ground and continuously discharges the photosensitive liquid from an outlet opening on the inner side during the rising process of the drum 1. It is applied by letting it dry.

As long as the coating head as the coating means used in the present invention has a basic structure that is arranged around the outer surface of the drum 1 and applies a coating liquid to the outer surface of the drum 1, it is possible to No. 189061, JP-A-60-5053
7, etc. can be adopted as appropriate.

An example of this is shown in FIG. This coating head 2 is a slide hopper type coating head.

To explain this, a narrow coating liquid distribution slit 22 having a coating liquid outlet 21 opening toward the drum 1 is formed in the coating head 2 in the horizontal direction. This slit 2
2 communicates with a liquid reservoir header 23, and a photosensitive liquid is supplied to this liquid reservoir header 23 by a pressure pump (not shown).

On the other hand, a liquid slide surface 25 is formed below the coating liquid outlet 21 of the slit 22 so as to continuously slope downward and terminate at a dimension slightly larger than the outer dimension of the drum 1.
Further, a lip-like portion 26 is formed extending downward from the terminal end of the liquid slide surface 25.

When such a coating head 2 is used, in the process of pulling up the drum 1, the photosensitive liquid is pushed out from the slit 22 and the coating liquid outlet 21, and is caused to flow down along the liquid sliding surface 25. The photosensitive liquid that has reached the lip 26 is applied to the outer surface of the drum 1 to a thickness corresponding to the clearance between the lip 26 and the drum 1.

In order to coaxially supply the drum 1 to this type of coating head 2, a ring-shaped pressure cylinder using fluid pressure is provided.

The pressure cylinder 3 in the first embodiment shown in FIG. 1 is arranged coaxially with the coating head 2, has a plurality of circumferentially long slits 3a on the surface of the drum 1, and has a plurality of axially long slits 3a inside the cylinder. The distribution chamber 3b is connected to air supply means such as a compressor.

In the positioning device configured in this way, the pressurizing cylinder 3
From each group of slits 3a, the pressure across the entire gap between the drum I side surface of the pressurizing cylinder 3 and the drum I outer surface is a pressure that can prevent the drum 1 from shifting, that is, preferably 0.1 to 2.
Air is supplied into the distribution chamber 3b at a rate of kg/aIr.

As a result, as shown in Fig. 4, when an external force acts that shifts the center axis of the drum 1, and the balance of pressure in the circumferential direction of the static pressure chamber collapses (P + > P t), the static pressure chamber As a result, as shown in FIG. 5, the center axis of the drum is prevented from shifting.

The side surface of the drum 1 of the pressurizing cylinder 3A can be formed into an appropriate shape other than the slit shape shown in FIG. 1, for example, a large number of small holes 3c can be formed as shown in FIG. 2.

Furthermore, in order to make the effect of the static pressure chamber more noticeable, as shown in FIG. 3, there is also a pressurizing cylinder 3B in which the upper wall 3d and the lower wall 3e are made to protrude from the front wall 3f to form a wide static pressure chamber 3g. Can be used.

In the present invention, the axial length H of the static pressure chamber is set to 50 or more, particularly preferably 100M or more. Also, the clearance G between the front wall of the pressurizing cylinder and the outer surface of drum I is 0.
It is preferable that it is 1-0.5B.

In the present invention, two or more pressure cylinders of the above example can be arranged in the axial direction of the drum 1. On the other hand, as for the arrangement position of the pressure cylinders, one or more pressure cylinders may not be provided only below the coating head 2, but a certain pressure cylinder or all the pressure cylinders may be provided above the coating head 2.

In the present invention, the spraying fluid may be not only air but also other gases, and liquids such as water may also be used.

As described above, the present invention is extremely effective as a coating device for manufacturing electrophotographic photoreceptors.

In this case, the photosensitive liquid may be one in which an inorganic photosensitive material such as zinc oxide or cadmium sulfide or an organic photosensitive material such as polyvinylcarbazole or trinitrofluorene is dispersed in a polymer binder. Furthermore, in recent years, in order to increase sensitivity and improve durability, functionally separated photosensitive layers in which a charge generation layer and a charge transport layer are laminated can also be used.

For example, the charge generation layer is made by dispersing azo pigments, quinone pigments, perylene pigments, phthalocyanine pigments, anthanthrone pigments, etc. in a polymeric binder such as polycarbonate, and the charge transport layer is made by dispersing polycyclic aromatic compounds, nitrogen-containing cyclic compounds, etc. It can be obtained by dispersing it in a molecular binder. The thickness of the charge generation layer is from 0.01 to 10 am, preferably from 0 to 0.
5 to 51 tm, and the thickness of the charge transport layer is preferably 5 to 51 tm.
~30 μm.

The viscosity of the photosensitive liquid is in the range of 0.5 to 70 Qcp, preferably in the range of 1 to 500 cp.

Further, hollow drums for electrophotography include aluminum, stainless steel, plastic on which a conductive layer is formed, and the like. Alternatively, an undercoat layer and a charge generation layer may be formed in advance.

〔Effect of the invention〕

As described above, according to the apparatus of the present invention, it is possible to accurately position the drum without damaging the drum, prevent uneven coating, and avoid increasing the amount of fluid used.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical sectional view of the first embodiment, FIG. 2 is a perspective view of another pressurizing cylinder example, FIG. 3 is a schematic vertical sectional view of another example, and FIGS. 4 and 5 are drums. 6 is a longitudinal sectional view of an example of a coating head, and FIG. 7 is a diagram illustrating the influence of a discharge flow on a coating layer when a spray nozzle is simply used. l...Cylindrical drum, 2...Applying head, 3.3A. 3B...pressure cylinder. Figure Figure

Claims (1)

[Claims] (1) A device for positioning the drum when manufacturing a photosensitive drum, surrounding the outer circumferential surface of the cylindrical drum and applying a coating liquid to the outer circumferential surface from a coating head; At the position where the coating liquid has been applied, a ring-shaped pressure cylinder is disposed coaxially with the drum and sprays fluid onto the drum outer circumferential surface with uniform discharge pressure from the entire outer circumference, and the pressure cylinder is arranged in the axial direction of the side surface of the drum. A photosensitive drum positioning device characterized by having a length of 50 mm or more.