JP2812755B2 - Manufacturing method of cylindrical coated body - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a cylindrical coated body on the surface of a cylindrical substrate as an object to be coated, and more particularly, for example, to an electrophotographic photosensitive member film How in the case of manufacturing, such as
With respect to the substrate surface of the photosensitive drum composed of a cylindrical substrate,
The present invention relates to a manufacturing method for forming a cylindrical coated body made of an organic photoconductor material into a continuous film.

[Conventional technology]

2. Description of the Related Art Conventionally, as a method for forming a cylindrical coated body into a continuous film on the surface of a cylindrical substrate which is an object to be coated of this kind, generally, a) dip coating method, b) Various means such as a ring coating method, c) a spray coating method, and d) a spiral coating method are known.

However, these conventionally used coating methods usually have the following disadvantages. A) dip coating method: dipping a cylindrical substrate into a coating liquid tank, and then pulling the cylindrical substrate to cause dripping of the coating liquid on the surface of the coating film, and concentration of the coating liquid in the liquid tank. It is easy to cause unevenness, so that the film thickness of the coating film is difficult to be constant, the required amount of the coating liquid is large, b) ring coating method; coating streaks are easily formed on the coated surface, c) spray coating method Low coating efficiency of coating liquid, waste of coating liquid, poor surface condition of coating film, d) spiral coating method; spiral coating film thickness unevenness is likely to occur on coating film surface. is there.

However, on the other hand, the spiral coating method has the disadvantage that the spiral film thickness unevenness is apt to occur on the coating film surface, but the required amount of the coating liquid is small, and the coating apparatus itself is also compared. It is an extremely preferable means because of its advantages such as simplicity.

[Problems to be solved by the invention]

Here, in the spiral coating method, the discharge nozzle is advanced in one direction to move relatively in a spiral shape while rotating the cylindrical substrate as the object to be coated, and the discharge is performed from the discharge nozzle. The coating liquid is applied to the surface of the substrate, and a discharge nozzle in this coating apparatus is, for example, a so-called slit nozzle or the like as disclosed in JP-A-52-119651. Is customary.

In this case, as in the case of forming an electrophotographic photoreceptor film, a coating liquid of an organic photoconductive material is applied to the surface of the photoreceptor drum in a continuous film form with a uniform and highly accurate film thickness as much as possible. When it is necessary to form the coating liquid in a uniform manner, the uniformity of the discharge flow rate in the coating width direction of the coating liquid discharged from the slit nozzle is a problem. This causes spiral film thickness unevenness on the film surface.

One reason for the non-uniformity of the coating film surface is that the thickness of the coating film applied to the surface of the photoreceptor drum is increased on the end side due to the surface tension of the coating liquid. The other is due to the accuracy of each unit for rotating the photosensitive drum at the time of coating and the fluctuation of the interval between the nozzle discharge opening end and the drum surface due to the roundness of the drum itself.

Thus, the non-uniformity of the coating film surface can be relatively easily eliminated by flattening and flattening the coating film surface using a blade or the like after application of the coating film, Such a method has a serious defect that a satisfactory coating surface cannot be formed at all, and the drum surface may be damaged by a blade or the like.

The present invention has been made to solve such a conventional problem, and an object thereof is to apply a spiral coating method using a discharge nozzle to form a coating body on a cylindrical substrate surface. The coating film was formed in a continuous film shape to obtain a uniform and highly accurate film thickness.
An object of the present invention is to provide a method for producing such a cylindrical coated body.

[Means for solving the problem]

In order to achieve the above object, a method for manufacturing a cylindrical coating body according to the present invention is applied by using a spiral coating method, using a multi-nozzle body for coating provided with a plurality of discharge pores, and fed. By discharging a coating liquid within a specific coating width range, a cylindrical coating body can be formed in a continuous film shape.

That is, the present invention relates to a method for producing a cylindrical coating body by forming a coating film on the surface of a cylindrical substrate which is an object to be coated, wherein the fed coating liquid is controlled within a specific coating width range. Using a multi-nozzle body for coating provided with a plurality of discharge pores for discharging, rotating the cylindrical body on a specific axis while bringing the multi-nozzle body for coating close to the surface of the cylindrical body Along with moving the coating multi-nozzle body parallel to the rotation axis, with respect to the surface of the cylindrical substrate,
Each discharge pore is caused to take a relatively spiral movement locus, by the relative movement of the plurality of discharge pores,
A method for manufacturing a cylindrical coated body, characterized in that a coating liquid discharged from each discharge pore is developed in a continuous film form on the surface of a cylindrical substrate, and a method for manufacturing the cylindrical coated body. In the method, the arrangement direction of the plurality of discharge pores in the multi-nozzle body for application is arranged so as to be inclined in the rotation axis direction of the cylindrical substrate, and with respect to the surface of the cylindrical substrate,
The application liquid is discharged from each of the discharge pores moved in a relative spiral trajectory.

[Action]

Therefore, in the method for manufacturing a cylindrical coating body of the present invention, by using a multi-nozzle body for coating provided with a plurality of discharge pores for discharging a supplied coating liquid within a specific coating width range. While rotating the cylindrical substrate to be coated on a specific axis, the coating multi-nozzle body disposed close to the surface of the cylindrical substrate is moved in parallel with the rotation axis. As a result, each of the discharge pores of the multi-nozzle body for application is moved relative to the surface of the cylindrical substrate along a spiral trajectory. The coating solution to be applied is spread on the surface of the cylindrical substrate and applied in a continuous film form, whereby the intended cylindrical coated body can be manufactured.

〔Example〕

Hereinafter, an embodiment of a method for manufacturing a cylindrical coating body according to the present invention and a multi-nozzle body for coating applied to the manufacturing method will be described in detail with reference to FIGS. 1 to 5.

FIG. 1 is a front view showing a schematic configuration of a multi-nozzle body for coating applied to a method of one embodiment of the present invention, and FIGS. 2 (a) to 2 (c) show a cylinder from each discharge nozzle of the multi-nozzle body for coating. FIGS. 3A and 3B are explanatory views sequentially showing a mode in which a coating liquid discharged onto the surface of the substrate is developed into a continuous film-like coating film. FIG. FIG. 4 is a partial perspective view for explaining the mode of each discharge nozzle of the multi-nozzle body for application applied to another embodiment of the method of the present invention, and FIG. FIG. 1 is a perspective view schematically showing an entire apparatus for forming a coating body on the surface of a cylindrical substrate by the method of this embodiment.

In this embodiment, by moving the discharge nozzle in a direction parallel to the rotation axis while rotating the cylindrical substrate which is the object to be coated, the surface of the cylindrical substrate to be coated is A spiral coating method is adopted in which the discharge nozzle takes a relative spiral trajectory, and the coating liquid discharged from the discharge nozzle is spread and applied to the surface to be coated. And in this case, the cylindrical substrate is 1
During the rotation, the discharge nozzle is moved by an amount corresponding to the coating width, so that the coating film is not repeatedly applied or uncoated.

As shown in FIG. 1, the discharge nozzle has a plurality of discharge holes 12a, each of which has a discharge pore 12a, so that the supplied coating liquid can be discharged within a specific coating width range. of the discharge tubule 12 but using the coating multi-nozzle member 11 which is disposed at predetermined intervals, in conjunction with the movement of the coating for multi-nozzle member 11 by the spiral trajectory of the discharge of each of these discharge tubule 12 fine The coating liquid discharged from the hole 12a is, as shown in FIGS.
The cylindrical substrate, which is attached to the surface 21a of the photosensitive drum 21 to be coated and is sequentially leveled to form a desired continuous film.

In this case, the discharge pores 21a provided and opened in the application multi-nozzle body 11 do not necessarily need to be formed by providing each discharge thin tube 12, and, for example, the internal feed furnace of the nozzle body itself is disposed at a predetermined interval. Of course, it may be made to branch and to make it open directly to the outside.

Here, for each of the plurality of discharge pores 12a,
The surface area and viscosity of the coating liquid used, the contact angle between the drum surface and the coating liquid to be discharged, and the coating film to be spread and coated are determined by the opening cross-sectional area of each discharge pore and the distance between the openings. It is important to make a proper selection according to each coating condition such as the film thickness of the film.

That is, the opening cross-sectional area of each discharge pore is selected and set according to the viscosity and the flow rate of the coating liquid. If this opening cross-section is too small, the pressure loss at each discharge pore becomes large. On the other hand, if the desired flow rate cannot be obtained, and if the cross-sectional area of the opening is too large, it is not preferable because the flow rate at each discharge pore varies. The distance between the opening of each discharge pore and the surface of the drum may be such that the applied coating liquid can be leveled as described below after the applied coating liquid adheres to the surface of the drum. In some cases, a continuous film having a sufficiently uniform thickness can be formed even at intervals of 5 mm or more.However, when the flow rate is low, it may be necessary to approach the thickness to about 0.1 mm. The application conditions are the surface tension, viscosity,
It is a prerequisite for performing good coating that selection should be made so that a coating film can be formed most effectively according to the flow rate and the like.

That is, as shown in the nozzle configuration of FIG. 1, a multi-nozzle body 11 for application in which discharge pores 12a are opened in each discharge thin tube 12 is used, and each discharge pore 12a is arranged in parallel to the traveling direction. In the case where the intended coating operation is performed based on the spline-like movement trajectory, the coating liquid A immediately after the coating on the coating target surface 21a of the photoconductor drum 21 is firstly obtained as shown in FIG. As seen in the cross section of a), each discharge pore
Are spaced at intervals corresponding to the arrangement distances of the one-way at 12a, may恰, although somewhat Moriaga ivy is the intended state a ₁ as occurring uneven coating, previously described When the application conditions are appropriately set, the contact angle between the drum surface 21a and the applied coating liquid A is small, and the viscosity of the coating liquid A itself is relatively low, the cross section shown in FIG. as, naturally by the flow connexion of the coating liquid a itself, which starts spreading immediately Yuki tied thereof to adjacent each other in sequence, in order it is automatically migrated to a series in Shigeruga ivy intermediate state a _2, This uneven coating state is gradually eliminated, and finally,
As can be seen from the cross section of FIG. 3C, the entire coating liquid A is leveled, and a coating film B formed into a continuous film with a desired set film thickness can be formed.

On the other hand, when the respective application conditions are not appropriate and the contact angle between the drum surface 21a and the discharged coating liquid A is large, or when the viscosity of the coating liquid A itself is relatively large, the coating liquid A Does not spread, but presents a streak, and a streaky uncoated portion corresponding to this appears. In this case, for example, even if an attempt is made to further narrow the interval between the openings of the discharge pores 12a, not only is there a restriction in terms of manufacturing and dimensional aspects, but also the viscosity of the coating liquid A is reduced. However, if the viscosity is too low, the wet film thickness becomes abnormally thin, causing dripping.

Therefore, as one means for improving such a point, as shown in FIG. 3, in order to reduce the interval between the openings of the discharge pores 12a, in It is conceivable that the discharge openings of the discharge pores 13a are not arranged in one direction and are arranged in a staggered arrangement. When one of the sides of the coating film B attached relatively later comes into contact with the sides of each of the coating films B on both sides attached to, the mutual fusion is made from this contact portion, and This is attracted only to the side that has once contacted due to the surface tension acting between the two, and the gap with the other side that did not fuse is increased, resulting in the expected continuous film-like coating film. B may not be obtained.

Therefore, as means for coping with such a case, as shown in FIG. 4, the discharge openings of the discharge pores 12a in the discharge narrow tubes 12 are arranged in one direction. This can be inclined by a predetermined angle θ in the direction of movement of the multi-nozzle body 11 , and can be arranged in substantially the same manner as reducing the interval between the respective discharge openings. Therefore, in this case, the film B portion to be attached later is sequentially fused to the film B portion to be attached earlier, and as a result, the uniform film thickness having the expected continuous film shape is obtained. Can be formed. In this case, the inclination angle θ is adjusted in consideration of various conditions such as the surface tension and viscosity of the coating liquid A and the contact angle between the drum surface 21a and the discharged coating liquid A. In many cases, the thickness is preferably about 15 to 75 ° in order to obtain a coating film B having a uniform thickness.

FIG. 5 shows one embodiment of a coating apparatus to which the coating multi-nozzle body 11 according to each embodiment is applied.

That is, the cylindrical base as the object to be coated, that is, the photosensitive drum 21 is appropriately pivoted and supported by a bearing so that the center axis is horizontal, and the coating multi-nozzle body 11 is The discharge pores 12a are arranged in a spiral shape relative to the drum surface 12a of the photosensitive drum 21 by disposing the photosensitive drum 21 in close proximity to the surface 21a to be coated and moving the photosensitive drum 21 in parallel with the rotation axis. So that it can be moved along the locus.

Thus, the rotational speed of the photosensitive drum 21 and the moving speed of the multi-nozzle body 11 for application need to be related to each other so as to be able to move accurately on a predetermined relative spiral trajectory. Therefore, the driving means for these rotation and movement include, for example, controllable driving sources 31 and 3 such as a stepping motor and a servomotor.
It is preferable to use 2. The moving means usually employs a ball screw mechanism 33 suitable for performing smooth movement, and the feed pump 34 for the coating liquid A can accurately control the flow rate. Preferably, there is. The rotation speed of the photosensitive drum 21 , the moving speed of the multi-nozzle body 11 for coating, and the flow rate of the coating liquid A are all set to be constant to perform the coating operation.

On the other hand, the liquid property range of the coating liquid A is relatively wide, but differs depending on the wet film thickness of the formed coating film B. That is, when the film thickness is small, relatively low viscosity is required, and when the film thickness is large, relatively high viscosity is required. Further, with respect to the solvent evaporation rate or the curing rate of the coating liquid A, if it is too fast, the viscosity of the adhered film increases before leveling, resulting in poor leveling.

Next, specific examples when the present invention is actually implemented and comparative examples corresponding thereto will be described.

Specific Example I. As the cylindrical substrate to be coated, the outer diameter is 80 mm,
Using a photosensitive drum substrate made of aluminum with a thickness of 1 m and a length of 340 mm, the inner diameter of the coating solution was 0.15 mm
Using a multi-nozzle body for coating, in which five discharge nozzles consisting of narrow tubes are arranged in a row at 0.85 mm intervals, the distance between the surface of the photosensitive drum and the discharge opening end of each nozzle is 0.1 mm, and The arrangement direction of each nozzle was arranged parallel to the rotation axis of the drum.

As a coating liquid, a phenoxy resin, a polyvinyl butyral resin, and a 4-methoxy-4-methyl-pentanone-dispersion of a charge generating substance (solid content: 1.5 wt%, surface tension: 28.2 dyn / cm, viscosity: 3 cps) were used. The coating liquid is discharged at 11 ml / min from each nozzle discharge opening of the multi-nozzle body for coating, the photosensitive drum is rotated at 320 rpm, and the multi-nozzle body for coating is arranged parallel to the rotation axis, and the feed pitch is Was set at 4.25 mm / rotation, and the coating operation was performed while moving the multi-nozzle body for coating relative to the surface of the photosensitive drum along a spiral movement locus.

Immediately after coating, spiral coating unevenness was observed on the coating surface, but it was gradually leveled, and then dried with far-infrared rays. As a result, a uniform charge of 0.6 μm in film thickness was generated. A coating film as a layer was obtained.

Example II. The same photosensitive drum as in Example I was used as the cylindrical substrate as the object to be coated, and four ejection nozzles each composed of a thin tube having an inner diameter of 0.39 mm were used as the means for discharging the coating liquid.
Using a multi-nozzle body for coating arranged in a line at an interval of mm, the distance between the surface of the photosensitive drum and the discharge opening end of each nozzle is 0.1 mm, and each nozzle is arranged with respect to the drum rotation axis. The directions were arranged at a tilt angle of 37 °.

As a coating solution, a cyclohexanone solution (solid content concentration: 17 wt%, surface tension: 29.7 dyn / cm, viscosity: 90 cps) of a polycarbonate resin, a charge generating substance, and an additive was used. At the same time as discharging at 40 ml / min from the nozzle discharge opening, the photosensitive drum is rotated at 255 rpm, and the coating multi-nozzle body is set at a feed pitch of 4 mm / rotation, and the coating multi-nozzle body is applied to the surface of the photosensitive drum. The coating operation was performed while moving along a relatively spiral locus.

Immediately after the application, a spiral coating unevenness was observed on the application surface, but this was gradually leveled. After that, this was dried with far infrared rays.
A coating film as a charge generation layer having good uniformity of ± 0.2 μm was obtained.

Specific Example III. In specific example II, the arrangement direction of each nozzle is arranged parallel to the drum rotation axis, and the photosensitive drum is
When the coating operation was performed in the same manner except that the rotation was performed at 204 rpm and the multi-nozzle body for coating was set at a feed pitch of 5 mm / rotation, streaky uncoated portions were generated at several places.

Comparative Example I. The same photosensitive drum substrate as in Example I was used as a cylindrical substrate as an object, and a slit having a width of 0.1 mm and a length of 3.7 mm was opened as a means for discharging a coating liquid. Using a slit nozzle, the distance between the surface of the photosensitive drum and the discharge opening end of the slit was 0.1 mm, and the same coating liquid as in Example II was discharged at 40 ml / min.
The coating operation was performed while rotating the coating nozzle at 6 prm and the feed multi-nozzle body at a feed pitch of 3.7 mm / rotation, while moving the slit nozzle relative to the surface of the photosensitive drum along a spiral locus.

Immediately after the application, a large thickness unevenness was generated on the coating film surface. This level was not leveled until the end, and after drying, the unevenness was clearly confirmed by visual inspection.

〔The invention's effect〕

As described in detail above, according to the coating method of the present invention,
Using a coating multi-nozzle body provided with a plurality of discharge pores for discharging the supplied coating liquid within a specific coating width range, a cylindrical substrate as an object to be coated is positioned on a specific axis. While rotating, the multi-nozzle body for coating arranged close to the surface of the cylindrical substrate to be coated is advanced in parallel with the axis of rotation. On the other hand, in a state where the coating multi-nozzle body is relatively moved along a spiral locus, the coating discharged from each of these discharge pores is caused by the movement of the coating multi-nozzle body along the spiral locus. The liquid can be successively applied to the surface of the cylindrical substrate, and by the subsequent leveling, the initial coating film can be quickly and easily formed into a continuous film with a uniform film thickness. And in this way For example, easily forming a coating film high accuracy is required, such as the photoconductor film in an electrophotographic photoreceptor.

Further, in the present invention, a multi-nozzle body for coating is used in which a plurality of discharge pores are linearly arranged at predetermined intervals so that the fed coating liquid can be discharged within a specific coating width range. Therefore, with the movement of each discharge pore relative to the surface of the cylindrical substrate by the spiral trajectory, the coating liquid discharged from each of the discharge pores is applied to the surface of the cylindrical substrate to be coated. Can be sequentially and satisfactorily and effectively adhered and applied, and, as described above, through subsequent leveling, an initial applied film can be quickly and easily formed into a continuous film with a uniform film thickness. In addition, it has excellent features such as a relatively simple structure and easy implementation.

[Brief description of the drawings]

FIG. 1 is a front view showing a schematic configuration of a multi-nozzle body for coating applied to a method of one embodiment of the present invention, and FIGS. 2 (a) to 2 (c) show a cylinder from each discharge nozzle of the multi-nozzle body for coating. FIG. 3 is an explanatory view sequentially showing a mode in which a coating liquid discharged onto the surface of a substrate is developed into a continuous film coating film. FIG. 3 supplements the embodiment for forming a continuous film coating film. FIG. 4 is a partial perspective view illustrating the form of each discharge nozzle of a multi-nozzle body for application applied to a method of another embodiment of the present invention, and FIG. 5 is a cylindrical shape according to the method of this embodiment. It is the perspective view which represented typically the whole apparatus which forms the application body on the surface of a base material. 11: Multi-nozzle body for application, 12: A plurality of discharge thin tubes arranged linearly in the multi-nozzle body, 12a: Discharge pores of each discharge thin tube, 21: Photoconductor drum (cylindrical substrate) ,twenty one
a: Drum surface (surface to be coated), 31, 32: Drive source, 33: Ball screw mechanism, 34: Feed pump, A:
Coating liquid, a ₁ ... Initial state of coating liquid, a ₂ ... Intermediate state of coating liquid, B... Coating film.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B05D 1 / 26,1 / 04,1 / 42 B05C 5 / 00,5 / 02

Claims (2)

(57) [Claims] 1. A method for producing a cylindrical coating body by forming a coating film on a surface of a cylindrical substrate as an object to be coated, comprising discharging a fed coating liquid within a specific coating width range. Using a multi-nozzle body for application in which a plurality of discharge pores are arranged, and rotating the cylindrical body on a specific axis while bringing the multi-nozzle body for application close to the surface of the cylindrical base. Moving the coating multi-nozzle body in parallel with the rotation axis so that each discharge pore takes a relatively spiral movement trajectory with respect to the surface of the cylindrical substrate; Wherein the coating liquid discharged from each of the discharge pores is spread in a continuous film form on the surface of the cylindrical substrate by the relative movement of the cylindrical coating body. 2. A dispensing direction of a plurality of discharge pores in the multi-nozzle body for application is arranged so as to be inclined with respect to a rotation axis direction of a cylindrical base, and a spiral relative to a surface of the cylindrical base is provided. The method for producing a cylindrical coated body according to claim 1, wherein the coating liquid is discharged from each of the discharge pores moved along a trajectory.