JPH03280065A - Positioning device for photosensitive drum - Google Patents

Abstract

PURPOSE:To position a drum without scratching the drum and to prevent faulty application by providing a shutoff wall for preventing a fluid discharge flow from moving to an application head from the discharge opening between the discharge opening and the application head and inclining the inner periphery side of the wall to a blow means side. CONSTITUTION:The blow means 3 which blows the fluid from the discharge opening so as to position the cylindrical drum 1 with fluid pressure is provided at the position of the cylindrical drum 1 where coating liquid is not applied yet or where it is already applied. Then, the shutoff wall 5 for preventing the fluid discharge flow from moving to the application head 2 from the discharge opening is provided between the discharge opening of the means 3 and the head 2, and the inner periphery side of the wall 5 is inclined to the means 3 side. Since at least the inner periphery side of the wall 5 is inclined to the blow means side, the fluid is quickly guided along the inclination in a direction where it is distant from the drum 1, thereby enhancing a fluid shutoff effect and preventing the faulty application.

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 causes 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 application head 2 while the drums 1 are successively connected and moved, the position of the drums is determined by air pressure from the horizontally arranged air blowing nozzle 3. At this time, after the discharged air once hits the outer surface of the drum 1, a portion of the air rises and flows toward the coating head 2, and sometimes escapes upward through the gap between the coating head 2 and the outer surface of the drum 1. In this case, the application of the photosensitive liquid may be uneven or defective, resulting in a failure to perform smooth application.

Therefore, the main object of the present invention is to position the drum without damaging the drum and to eliminate the influence on the coating by the coating head.

[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, a spraying means is provided that sprays fluid from a discharge port and positions the cylindrical drum using the fluid pressure at a position where the coating liquid has been applied, and further, between the discharge port and the application head, the fluid is sprayed from the discharge port of the fluid discharge flow. This can be solved by providing a blocking wall that prevents the transfer to the coating head, and at least the inner peripheral side of this blocking wall is inclined toward the spraying means side.

[For production]

In the present invention, the cylindrical drum is positioned by spraying fluid onto its outer peripheral surface and using the fluid pressure. That is,
When a fluid, such as air, is blown around the drum,
The spray pressure neutralizes the position of the drum, thereby making it possible to position the drum 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 blocking wall is provided to prevent the fluid discharged from the discharge port of the spraying means from going toward the coating head, it is possible to prevent coating defects during coating from the coating head. Furthermore, when the blocking wall is horizontal or inclined toward the coating head side, the blocking wall easily passes through a small gap between the inner peripheral edge of the blocking wall and the outer surface of the drum and moves toward the coating head side. Since at least the inner peripheral side of the drum is inclined toward the spraying means side, the fluid can be quickly guided away from the drum along the inclination, thereby increasing the fluid blocking effect. Furthermore, in the case where the above-mentioned blocking wall is horizontal or inclined toward the coating head side, the effect is not sufficient and the gap between the inner peripheral edge of the blocking wall and the outer surface of the drum is less than 0.1 mm. If the gap is narrow, it is easy to cause scratches on the outer surface of the drum, whereas the inclined blocking wall according to the present invention has a high effect of excluding fluids such as air, so that the inner peripheral edge of the blocking wall is within 3M of the outer surface of the drum. Even with the above gap, poor coating can be prevented.

〔Example〕

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

1 and 2 show 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 by an appropriate gripping means. By alternately gripping it, it is made to rise continuously.

Reference numeral 2 denotes an annular coating head for applying photosensitive liquid to the outer circumferential surface of drum 1, which is fixedly installed on the ground and continuously discharges photosensitive liquid from an outlet opening on the inner side during the rising process of 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, positioning spraying means using fluid pressure is provided.

In the first embodiment shown in FIGS. 1 and 2, three blowing nozzles 3 for blowing air are arranged horizontally at equal intervals in the circumferential direction, that is, at intervals of 120 degrees. In addition, high-pressure air is supplied to each nozzle 3 from a compressor 4, and is blown at high speed toward the outer peripheral surface of the drum 1 from the discharge port of each nozzle 3 with a uniform discharge amount and pressure. . As a result, the axial center of the drum 1 is positioned identically with respect to the central axis of the coating head 2. Therefore, the photosensitive liquid from the coating head 1 is applied to the outer peripheral surface of the drum 1 with a uniform coating thickness.

However, in this case, the air discharged from each nozzle 3 is directed toward the coating head 2 side, causing coating defects.

Therefore, in the present invention, as shown in FIG. 1, for example, a ring-shaped blocking wall 5 inclined toward the nozzle 3 side is provided with its inner edge close to the outer peripheral surface of the drum 1.

By installing this blocking wall 5, air can be prevented from moving to the coating head 2, as shown in the figure. In particular, since the blocking wall 5 is inclined toward the nozzle 3 side, air can escape smoothly.

Note that the number of nozzles 3 in the circumferential direction is not limited as long as it is plural.

FIG. 3 shows a ring-shaped nozzle 3A with a continuous slit 3a opened on the drum 1 side. Moreover, the blocking wall 5A in this case is an example in which the entirety is not inclined, but only the inner part thereof is inclined.

The example in FIG. 4 is an example in which two blocking walls 5B, 5B are arranged in the axial direction. Further, the blocking wall 5B in this example is not a straight plane but is inclined in a curved line like a turbine blade. The separation distance between the inner peripheral edge of each of the blocking walls 5B, 5B and the surface of the drum 1 can be made to be different from each other such that it is smaller on the nozzle 3 side.

In the present invention, two or more nozzles of the above example can be arranged in the axial direction of the drum 1. In this case, 1. Since the distance from each nozzle to the drum 1 is equalized, it is possible to prevent the drum 1 from tilting as a result.

On the other hand, as for the arrangement position of the nozzles 3, one or more nozzles 3 may not be provided only below the coating head 2, but a certain nozzle or all the nozzles may be provided above the coating head 2. In the example shown in FIG. 5, nozzles 3.3 are provided below and above the coating head 2, and corresponding blocking walls 5B, 5B are provided.

Note that the inclination angle (typically θ shown in FIG. 3) is preferably 60 degrees or less.

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 0.01 to 10 μm, preferably 0.05 to 10 μm.
5 μm, and the thickness of the charge transport layer is preferably 5 to 3 μm.
It is 0 μm.

The viscosity of the photosensitive liquid is in the range of 0.5 to 700 cp, 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 position the drum without causing any scratches on the drum, and to eliminate the influence on the coating by the coating head.

[Brief explanation of drawings]

FIG. 1 is a schematic longitudinal sectional view of the first embodiment, FIG. 2 is a plan view thereof, FIGS. 3 to 5 are schematic longitudinal sectional views of other examples, and FIG. 6 is a longitudinal sectional view of an example of a coating head. , FIG. 7 is an explanatory diagram of the influence of the discharge flow on the coating layer when no blocking wall is provided. 1... Cylindrical drum, 2... Application head, 3.3A.
... Spray nozzle, 3a... Slit, 5.5A, 5B
...blocking wall. Figure Figure 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 spraying means is provided that sprays fluid from the discharge port and positions the cylindrical drum using the fluid pressure, and further, between the discharge port and the coating head, the fluid is sprayed from the discharge port of the fluid discharge flow. 1. A positioning device for a photosensitive drum, comprising a blocking wall for preventing transfer to a head, and at least an inner peripheral side of the blocking wall is inclined toward a blowing means side.