JP2811220B2 - Photosensitive drum positioning device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for positioning a cylindrical drum when manufacturing an electrophotographic photosensitive member 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 solution is applied to a cylindrical drum. For the application, it is necessary to perform an adjustment operation of positioning a slide hopper at a predetermined position around the cylindrical drum and maintaining a constant clearance between them in the circumferential direction. In this case, since the required thickness of the coating layer is extremely small, even if the cylindrical drum is displaced 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 a deviation in the thickness of the coating layer causes various inconveniences such as a change in the amount of charge, an uneven sensitivity, and a change in the residual potential in the circumferential direction of the cylindrical drum. Therefore, accurate positioning of the cylindrical drum is extremely important.

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

[Problems to be solved by the invention]

However, in this type of conventional device, since the position regulating roller is positioned while directly contacting the drum, there is a problem that the drum is damaged. It is well known that electrophotographic properties deteriorate when a drum is damaged.

Therefore, in positioning the drum, the present inventors
For example, it has been found that when the positioning is performed by blowing air, the drum can be prevented from being damaged, which is extremely effective.

However, as shown in FIG. 7, when the photosensitive liquid L is applied from the application head 2 in the process of sequentially connecting and moving the drums 1, each of the air blowing nozzles 10 arranged in a horizontal direction at, for example, three places in the circumferential direction. When the drum 1 is positioned by the air pressure, after the discharged air once hits the outer surface of the drum 1, a part of the air rises and flows toward the coating head 2, and the gap between the coating head 2 and the outer surface of the drum 1 is increased. It may come off and go up. In this case, coating defects such as horizontal unevenness and running out of the photosensitive liquid are caused.

In addition, unless a large amount of air is blown out, it is difficult to position the drum 1 and the production cost is increased.

Therefore, a main object of the present invention is to perform accurate positioning of the drum without damaging the drum, prevent coating unevenness, and avoid increasing the amount of fluid used.

[Means for solving the problem]

An object of the present invention is to provide an apparatus for positioning a drum when a coating liquid is applied from an application head to an outer peripheral surface of a cylindrical drum when the photosensitive drum is manufactured by surrounding the outer peripheral surface of the cylindrical drum; Alternatively, at a position where the coating liquid has been applied, a ring-shaped pressurizing cylinder for spraying a fluid to the outer peripheral surface of the drum with a uniform discharge pressure from the entire outer periphery is disposed coaxially with the drum, and a shaft on the drum side surface of the pressurizing cylinder. The problem can be solved if the length in the direction is 50 mm or more.

(Operation)

In the present invention, a fluid is sprayed on the outer peripheral surface to position the cylindrical drum by the fluid pressure. That is, when a fluid, for example, air is blown from the periphery of the drum, the blowing pressure neutralizes the position of the drum, thereby positioning the drum at a predetermined position.

Moreover, since there is no mechanical contact with the drum, it is possible to prevent the drum from being damaged.

On the other hand, since the ring-shaped pressurizing cylinder that sprays fluid to the drum outer peripheral surface with the blowing pressure uniformly from the entire outer periphery is disposed coaxially with the drum, when the blowing pressure is reduced, the inner surface of the pressurizing cylinder and the drum A static pressure chamber can be formed with the outer surface. In the state in which the static pressure chamber is formed, an external force that shifts the center axis of the drum acts, and if the pressure balance in the circumferential direction of the static pressure chamber becomes unbalanced, the pressure is canceled to make it equal pressure. As a result, displacement of the center axis of the drum is prevented.

Therefore, the amount of air used to make the pressure equal is very small, so that the power cost of the compressor can be reduced.

〔Example〕

 The present invention will be described in more detail with reference to examples.

FIG. 1 shows a first embodiment, in which 1 is a drum having a hollow cylindrical shape, for example, and a conveying means (not shown), for example, the bottom of the drum is raised by a cylinder or the like, or alternately gripped by an appropriate gripping means. As a result, it rises continuously.

Reference numeral 2 denotes an annular coating head for applying a photosensitive liquid to the outer peripheral surface of the drum 1, which is fixed to the ground, and
During the ascending process, the photosensitive liquid is applied by continuously discharging the photosensitive liquid from an outlet opened on the inner surface side.

As a coating head as a coating means used in the present invention, if a coating head is disposed on the outer surface of the drum 1 so as to surround it and has a basic structure for coating the coating liquid on the outer surface of the drum 1, Japanese Patent Laid-Open No. For example, those disclosed in JP 189061, JP-A-60-50537, etc.

This example is shown in FIG. The coating head 2 is a slide hopper type coating head.

Explaining this, a narrow coating liquid distribution slit 22 having a coating liquid outlet 21 opening to the drum 1 side is formed in the coating head 2 in the horizontal direction. The slit 22 communicates with a liquid reservoir header 23.
Is supplied by a pressure pump (not shown).

On the other hand, a liquid slide surface 25 is formed below the application liquid outlet 21 of the slit 22 so as to continuously incline in a downward constriction and terminate at a dimension slightly larger than the outer dimension of the drum 1. Lip extending below the end of the liquid slide surface 25
26 are formed.

When the coating head 2 is used, the photosensitive liquid L is supplied to the slit 22 and the coating liquid outlet in the process of lifting the drum 1.
It is extruded from 21 and flows down along the liquid slide surface 25. The photosensitive liquid L that has reached the lip 26 is applied to the outer surface of the drum 1 with a thickness substantially corresponding to the clearance between the lip 26 and the drum 1.

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

The pressurizing cylinder 3 in the first embodiment shown in FIG. 1 is arranged coaxially with the coating head 2, and its drum 1 has a plurality of slits 3a extending in the circumferential direction on the surface thereof in a plurality of axial directions. The distribution chamber 3b is connected to air supply means such as a compressor.

In the positioning device configured as described above, the pressure in the entire gap between the side surface of the drum 1 and the outer surface of the drum 1 of the pressurizing cylinder 3 is such that the displacement of the drum 1 can be prevented from the group of slits 3a of the pressurizing cylinder 3. Pressure, i.e. preferably 0.1-2 kg / cm ²
Is supplied into the distribution chamber 3b such that

As a result, as shown in FIG. 4, when an external force that shifts the center axis of the drum 1 acts and the pressure balance in the circumferential direction of the static pressure chamber is lost. When P ₁ > P ₂ , the static pressure chamber Therefore, the displacement of the center axis of the drum is prevented as shown in FIG.

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

Further, in order to make the effect of the static pressure chamber remarkable, as shown in FIG. 3, an upper wall 3d and a lower wall 3e protrude from the front wall 3f to form a pressurizing cylinder 3B having a wide static pressure chamber 3g. Can be used.

In the present invention, the axial length H of the static pressure chamber is at least 50 mm, particularly preferably at least 100 mm. The clearance G between the front wall of the pressurizing cylinder and the outer surface of the drum 1 is 0.1
It is preferably 0.5 mm.

In the present invention, two or more pressurizing cylinders of the above example can be arranged in the axial direction of the drum 1. On the other hand, as the disposition position of the pressure cylinder, one or a plurality of pressure cylinders may be provided above the coating head 2 without providing one or more pressure cylinders only below the coating head 2.

In the present invention, as the spray fluid, other gas may be used other than air, and a liquid such as water may be used.

As described above, the present invention is extremely effective as a coating device for producing an electrophotographic photosensitive member. As the photosensitive liquid in this case, an inorganic photosensitive material such as zinc oxide or cadmium sulfide, or a liquid in which an organic photosensitive material such as polyvinyl carbazole and trinitrofluorene is dispersed in a polymer binder can be used. In recent years, a function-separated type photosensitive layer in which a charge generation layer and a charge transport layer are laminated can also be used in order to increase sensitivity and improve durability.

For example, the charge generation layer disperses an azo pigment, a quinone pigment, a perylene pigment, a phthalocyanine pigment, an anthranthrone pigment, etc. in a polymer binder such as polycarbonate,
The charge transport layer can be obtained by dispersing a polycyclic aromatic compound, a nitrogen-containing cyclic compound and the like in a polymer binder. The thickness of the charge generation layer is from 0.01 to 10 μm, preferably from 0.05 to 5 μm, and the thickness of the charge transport layer is preferably from 5 to 30 μm. The viscosity of the photosensitive solution is in the range of 0.5 to 700 cp, preferably 1 to 700 cp.
It is in the range of ~ 500cp.

Examples of the hollow drum for electrophotography include aluminum, stainless steel, plastic on which a conductive layer is formed, and the like. Further, an undercoat layer or a charge generation layer may be formed first.

〔The invention's effect〕

As described above, according to the apparatus of the present invention, accurate positioning of the drum can be performed without damaging the drum, coating unevenness can be prevented, and an increase in the amount of fluid used can be avoided.

[Brief description of the drawings]

1 is a schematic longitudinal sectional view of the first embodiment, FIG. 2 is a perspective view of another example of a pressurizing cylinder, FIG. 3 is a schematic longitudinal sectional view of another example, and FIGS. 4 and 5 are drums. FIG. 6 is a longitudinal sectional view of an example of a coating head, and FIG. 7 is an explanatory diagram of the effect of a discharge flow on a coating layer when a spray nozzle is simply used. 1 ... Cylindrical drum, 2 ... Coating head, 3, 3A, 3B ...
Pressurizing cylinder.

────────────────────────────────────────────────── ─── Continuing on the front page (72) Kazuyuki Shimizu, Konica Corporation, 1 Sakura-cho, Hino-shi, Tokyo (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 5/05

Claims (1)

(57) [Claims] 1. An apparatus for positioning a drum when a coating liquid is applied from an application head to an outer peripheral surface of a cylindrical drum when the photosensitive drum is manufactured by surrounding the outer peripheral surface of the cylindrical drum; In the position or the position where the coating liquid has been applied, a ring-shaped pressurizing cylinder for spraying a fluid to the outer peripheral surface of the drum with a uniform discharge pressure from the entire outer periphery is disposed coaxially with the drum, and the pressurizing cylinder is provided on the side surface of the drum. A photosensitive drum positioning device having an axial length of 50 mm or more.