JPH03280066A - 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 sucking means for making fluid discharge flow from a discharge opening distant from the outer surface of the drum. CONSTITUTION:A blow means 3 which blows fluid from the discharge opening to position the cylindrical drum 1 with fluid pressure is provided at the position of the drum 1 where coating liquid is not applied or where it is already applied. Then, the sucking means for making the fluid discharge flow from the discharge opening distant from the outer surface of the drum 1 is provided between the discharge opening and the application head 2. Therefore, by actuating an exhaust pump in the case of applying photosensitive liquid, air which is discharged from a nozzle 3 group and flows to the head 2 side is exhausted to the outside of a closed chamber 6 because of the negative pressure in the chamber 6 and the air is prevented from escaping in a gap between the head 2 and the outer surface of the drum 1. Thus, the drum is positioned without scratching the drum and the faulty application is prevented.

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 a deviation of 0.1 mm from the cylindrical drum 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 positioning of the drum 1 is controlled by the air pressure from the horizontally arranged air blowing nozzle 3. During this process, after the discharged air hits the outer surface of the drum 1, a portion of it rises and flows toward the coating head 2, sometimes passing through the gap between the coating head 2 and the outer surface of the drum 1 and passing upward. . In this case, the photosensitive liquid may be applied unevenly or poorly, resulting in an uneven 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, at a position where the coating liquid has been applied, spraying means is provided for spraying fluid from a discharge port and positioning the cylindrical drum by the fluid pressure, and between the discharge port and the coating head, the fluid discharged from the discharge port is provided. This problem can be solved by providing suction means to keep the water away from the outer surface of the drum.

[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, if the air flow from the air blowing nozzle 3 is prevented from flowing to the coating head 2, the above-mentioned problem can be solved. Therefore, it is effective to provide a blocking wall 4 to prevent the air flow from the nozzle 3 from flowing toward the coating head 2, as shown in FIG. However, in reality, unless the gap between the inner peripheral edge of the blocking wall 4 and the outer surface of the drum I is less than 0.1, the effect is not sufficient. Misalignment can easily cause scratches on the outer surface of the drum.

In contrast, according to the present invention, between the nozzle 3 outlet and the coating head 2, the air flow is directed from the outlet to the drum I.
If a suction means is provided to keep it away from the outer surface of the drum 1, the inner circumferential edge of the cut-off wall can be moved away from the outer surface of the drum 1 by 3.
Even if the distance is 11II11 or more, coating defects such as uneven coating and liquid shortage 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 sliding surface 25 is formed below the second coating liquid outlet 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 (not shown), and is sprayed at high speed toward the outer peripheral surface of the drum 1 with a uniform discharge amount and pressure from the discharge port of each nozzle 3. It will be done. As a result, the tram 1 is precisely positioned identically with respect to the central axis of the application head 2. Therefore, the photosensitive liquid from the coating head 1 is applied to the outer peripheral surface of the drum I with a uniform coating thickness.

However, in this case, as described above, the air discharged from each nozzle 3 heads toward the coating head 2 side, causing coating defects.

Therefore, in the present invention, as shown in FIG. 1, a sealed chamber 6 facing the tram 1 side is formed between the nozzle 3 and the coating head 2 by a partition wall 5, and is communicated with the sealed chamber 6 as shown in the figure. Connect the exhaust pump that does not.

In such an apparatus of the present invention, when the exhaust pump is operated during coating of the photosensitive liquid, the air discharged from the three nozzle groups and flowing toward the coating head 2 is airtight, since the inside of the sealed chamber 6 is under negative pressure. Air is exhausted to the outside of the chamber 6, thereby preventing air from escaping in the gap between the coating head 2 and the outer surface of the drum I.

Therefore, the coating defects that occur in the prior art are prevented.

On the other hand, as described in connection with FIG. 7, it is effective to provide the blocking wall 4.

In the example shown in FIG. 3, a ring-shaped blocking wall 4 whose inner peripheral edge portion is inclined toward the nozzle 3 side is disposed with its inner edge close to the outer peripheral surface of the drum 1, and a space between this blocking wall 4 and the coating head 2 is provided. A closed chamber 6 is provided in the chamber. In this case, the air discharged from the nozzle 3 once collides with the outer surface of the drum 1 and then flows upward, but most of the air hits the blocking wall 4 and escapes outward. However, because a certain distance must be maintained between the inner peripheral edge of the blocking wall 4 and the outer surface of the drum, some air escapes through that gap and reaches the coating head 2.
flows to the side. However, since the suction means is provided between the blocking wall 4 and the coating head 2, poor coating can be prevented as described above. Note that, as in this example, when the blocking wall 4 and the suction means are used together, there is an advantage that a small suction means is sufficient.

The example in FIG. 4 is an example in which the suction means according to the present invention is provided between the nozzle 3 and the blocking wall 4.

In FIG. 5, an air exhaust fan 8 is connected to one or two suction rings 7 as shown, which are opened on the outer surface of the drum 1, without forming a closed chamber 6 as on each side, and the suction rings 7.
The air rising at the 7th part is removed.

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

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 between each nozzle and the re-drum 1 is equalized, it is possible to prevent the drum from tilting.

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 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. czm preferably 0.0
The thickness of the charge transport layer is preferably 5 to 5 μm.
It is 30 μm.

The viscosity of the photosensitive liquid is in the range of 0.5 to 700 Cp, preferably in the range of 1 to 5 oocp.

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 the suction means according to the present invention is not provided. DESCRIPTION OF SYMBOLS 1... Cylindrical drum, 2... Application head, 3... Spray nozzle, 4... Blocking wall, 5... Partition wall, 6...
- Sealed room, 7 - Suction nozzle, 8... Exhaust fan.

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; A spraying means for positioning the cylindrical drum by spraying fluid from a discharge port at a position where the coating liquid has been applied is provided, and a fluid discharge flow from the discharge port is provided between the discharge port and the coating head. A photosensitive drum positioning device comprising a suction means for moving the drum away from the outer surface of the drum.