JPS6232027A - Method for covering cylindrical article with cylindrical shrinkable film - Google Patents

Abstract

PURPOSE:To prevent the remaining of undesirable marks based on the fold of a film even when a cylindrical shrinkable film having a fold was used, by forming specific relation between the outer diameter dimension of an auxiliary jig in the diameter direction, the inner diameter dimension of a shrinkable film in the diameter direction corresponding to said outer diameter dimension and the outer diameter dimension of an article in the diameter direction. CONSTITUTION:The relation of phi3<phi1<phi2 is formed between the outer diameter dimension phi1 of an auxiliary jig in the diameter direction, the inner diameter dimension phi2 of a shrinkable film in the diameter direction corresponding to said outer diameter dimension phi1 and the outer diameter dimension phi3 of an article in the diameter direction. The film 12 is supplied from above in a folded state and sufficiently spread by an upper auxiliary cylinder 8 to be formed into a cylindrical shape. Therefore, the film 12 is inserted without being contacted with the surface of a base body. Because both ends of the film 12 are supported by the auxiliary cylinders 8, 10, shrinkage is started from the central part of the film 12 at first and a shrinking region is gradually enlarged to both end parts to perform good covering.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of coating a cylindrical article with a cylindrical shrinkable film. Such a coating method is applied, for example, to the protective round coating of various cylindrical articles.

[Conventional technology]

Conventionally, cylindrical heat-shrinkable films have been used for the purpose of protecting various articles. A cylindrical heat-shrinkable film is a cylindrical film that shrinks when heated, and by placing the cylindrical heat-shrinkable film over a predetermined article and heating it, it forms a covering that closely follows the surface shape of the article. is formed. As described above, by using a cylindrical heat-shrinkable film, it is possible to cover the surface in a short time by only heating, and therefore the cylindrical heat-shrinkable film is widely used for various packaging applications. However, when using cylindrical heat-shrinkable films to cover articles that require precision,
A cylindrical heat-shrinkable film that is as undamaged as possible is needed. However, cylindrical heat-shrinkable films obtained by conventional manufacturing methods generally have creases, and these creases have a negative effect on the coating of articles that require precision. For example, in the case of coating the surface of an electrophotographic photoreceptor, the image characteristics at the position corresponding to the fold of the film become extremely poor, resulting in image distortion and poor cleaning performance. It is.

The creases that occur in conventional cylindrical heat-shrinkable films are due to the manufacturing process. This will be explained using the drawings. FIG. 4 is a typical example of a conventional creation method. That is, the raw material resin 41 is supplied to the filament 4-45 and then thermally melted. The melted raw material resin advances along the arrow 47 and is extruded from the circular mold part 42. Then, compressed air is supplied from the inlet section 43 to stretch the extruded cylindrical film. The heated and melted raw material resin is transferred to the circular mold part 42.
While being pushed out, wound upward, and pulled apart,
At the same time, a stretching operation is carried out by introducing compressed air, and the cylindrical heat-shrinkable film 48 is folded by a roller 44 and wound up by a winding roller 45. As described above, creases occur when the manufactured cylindrical heat-shrinkable film is wound up.

In order to prevent the effects of creases as described above when forming an insulating layer by coating the surface of an electrophotographic photoreceptor that requires particularly good placement properties using a cylindrical heat-shrinkable film as described above,
For example, the following methods are used.

(1) A method of covering an electrophotographic photoreceptor with a cylindrical heat-shrinkable film and shrinking the film by heating it in a heating furnace at a temperature of about 100°C for about 15 to 20 minutes. (2) Cylindrical heat-shrinkable film covering an electrophotographic photoreceptor, and using a liquid as a heating medium, a step of primarily shrinking a portion of the film corresponding to the lower end of the photoreceptor in a high temperature region of the heat-shrinkable temperature region of the film, a low temperature region of the temperature region; A step of secondarily shrinking the film portion except for one portion corresponding to the upper end of the photoreceptor.

and a method comprising the step of tertiary shrinkage of a film portion corresponding to the entire photoreceptor in a high temperature part of the temperature range.

However, in the above method, when the shrinkable film is placed on the electrophotographic photoreceptor, the shrinkable film is folded and rapidly unfolded into a cylindrical shape, as shown in FIG. In addition, since the operation of directly covering the photoreceptor is performed immediately, the film is placed over the photoreceptor before it has a sufficiently cylindrical shape. As a result, creases and wrinkles remain in the film, and when the film shrinks, it cannot shrink uniformly over the entire surface, resulting in uneven film thickness, as shown in Figure 5(b). ] Air may remain. In addition, Fig. 5 (a), (b)r
(This is a 22-layer film with a 20Fi electrophotographic photoreceptor.The photoreceptor is scraped by the edges of the film.The film is then scraped by the sharp edges of the photoreceptor.) If f< is generated, the dust may remain or scratches may occur on the surface of the photoreceptor.

Therefore, there is a problem in that the characteristics of the electrophotographic photoreceptor are likely to deteriorate.

[Purpose of the invention]

The present invention provides a method in which, even when covering an article with a cylindrical shrinkable film having folds as described above, no inconvenient traces due to the folds or wrinkles of the film remain. The main purpose is to provide a simple coating method.

Another object of the present invention is to provide a coating method that does not cause injuries or damage to articles.

Furthermore, another object of the present invention is to provide a coating method that achieves excellent image quality when an electrophotographic photoreceptor is used as an article.

[Summary of the invention]

According to the present invention, in order to achieve the above object, when a cylindrical shrinkable film is placed over a cylindrical article and the core film is further shrunk, at least one end of the cylindrical article corresponds to the cylindrical shape VC of the article. An auxiliary jig having a cylindrical shape is attached to the article in a manner that corresponds in shape to the article, and the radial outer diameter φ1 of the auxiliary jig and the shrinkable film corresponding to the radial outer diameter dimension ζ are set. A method for covering a cylindrical article with a cylindrical shrinkable film, characterized in that a radial inner diameter dimension φ■ and a radial outer diameter dimension φ1 of the article satisfy the following relationship: is provided.

The cylindrical auxiliary jig has a cylindrical shape corresponding to the cylindrical article. For example, if the article is cylindrical, the auxiliary oil ^ is also cylindrical, and if the article is elliptical, the auxiliary jig is also cylindrical. If the article is an octagonal prism, the auxiliary jig is also octagonal.

The cylindrical auxiliary jig is attached with its shape corresponding to the article. That is, the auxiliary jig is attached as if it were an extension of the article, and the auxiliary jig plays the role of an aid when covering the article with the shrinkable sheet. The auxiliary jig may be attached only to one end of the article, but it can also be attached to both ends of the article.

When attached to both ends, one of the auxiliary jigs serves to support the edge of the cylindrical film that has been graded as an article from the inside.

Examples of methods for shrinking the shrinkable film include a heating method and an organic solvent method.

Examples of heating methods include (1) heating in a heating furnace maintained at about 80 to 150°C; and (2) heating at 80°C to 150°C.
Examples include heating by immersion in a liquid maintained at about 150 DEG C., such as water, ethylene glycol, glycerin, fi/1 rough-in, silicone oil, etc.

Examples of methods using organic solvents include (3) immersion in organic solvents capable of shrinking the shrinkable film, such as halogen-containing organic solvents such as methylene chloride; in this case, heating is not required. do not.

- Among the three shrinking methods specifically mentioned above, method (2) is particularly preferable because it causes less uneven shrinkage.

In addition, as a source of shrinkage energy, it is possible to stably supply shrinkage energy because it has a large specific heat and there is little temperature drop when the article is immersed, and it does not require removal of the medium, so it is especially suitable for heating water. is most preferable,
i In the method of the present invention, φ breath is selected so as to satisfy the relationship φ−〈φ鳳〈φ snow. Here, φ amount ~ φ- are the corresponding radial dimensions of the auxiliary jig, the shrinkable film, and the article, and in particular, φ is the cylindrical size of the shrinkable film corresponding to the cylindrical shape of the article and the auxiliary jig. This is the radial inner diameter dimension when the shape is maintained.

Therefore, if the article is cylindrical, φ1~φi is the diameter of the circle, and if the article is elliptical, φ凰~φaFi is, for example, the major axis or minor axis of the ellipse.
When the article has a diagonal shape, φ1 to φi are appropriate diagonal lengths, for example.

Thus, the shrinkable film is first folded into a cylindrical shape and then first placed on an auxiliary jig, where it is fully expanded into a cylindrical shape corresponding to the article 8 to cover the cylindrical surface of the article. be placed on top. Furthermore, if auxiliary jigs are scattered at both ends of the article, both ends Ij of the shrinkable film
k is supported by the auxiliary jig. As a result, the shrinkable film is sufficiently spread out onto the cylindrical surface of the article into a shape corresponding to the article, and folds and wrinkles disappear. In addition, since the possibility of the shrinkable film coming into contact with the article is extremely small, there is no possibility that the surface of the article will be damaged or the film will be scraped and "Cfi" etc. will occur.

When the shrinkable sheet is shrunk in this state, the shrinkage energy supplied to the film from the shrinkage source is uniformly provided to the entire surface of the film without being absorbed by the article, and thus the film shrinks uniformly over the entire surface. It will be done.

For example, when shrinking a shrinkable film by heating, when the film comes into contact with an article, the object A is removed from the contact area.
As K heat is absorbed, the temperature rise of the film in the contact area with the article is delayed, and the thickness of the film in the contact area also becomes thinner (as compared to the non-contact area), but as mentioned above, In the method of the present invention, the film does not come into contact with the article, so the film shrinks uniformly over the entire WJK,
A uniform film thickness is achieved over the entire surface, and no air remains.

In the method of the present invention, when shrinking a shrinkable film, K [pressure circle i applied to the product side surface of the shrinkable film and lI! on the other surface of the shrinkable film! The pressure applied by lK: Pout and f: Pout (By maintaining the relationship between Pout and Pout), the effect of expanding the lume into a cylindrical shape is further promoted, and it is possible to remove creases and wrinkles from the film, and to clean the walls. It is effective in preventing occurrence and damage to goods.

In the method of the present invention, it is also possible to form an auxiliary jig on the article in advance. In this case, the I/c is used together with the article without being removed from the article even after the jig Fi has been coated.

Furthermore, in the method of the present invention, the cylindrical surface of the auxiliary jig on the side opposite to the side to be connected to the article is made into a cylindrical shape, and the outer diameter of the end thereof is covered with a shrinkable film. Operation becomes much easier.

In the present invention, a variety of articles can be used to be coated, and a typical example is a substrate for an image holding member used in an electronic four-dimensional array.

Image holding members on which electrostatic images or toner images are formed include those having a photoconductive layer on a support called an electrophotographic photoreceptor, and those having no photoconductive layer. , usually consists of a support and an image-retaining layer thereon.

Note that electrophotographic photoreceptors have various configurations in order to obtain predetermined characteristics or depending on flI types of electrophotographic processes to which they are applied. A typical electrophotographic photoreceptor is a photoreceptor with a laminate of a photoconductive layer and an insulating layer as an image-retaining layer on a support. Envy, improved mechanical strength of photoreceptor, improved dark decay characteristics.

Alternatively, it is provided for a primary purpose in order to be applied to a specific electrophotographic process. Typical examples of electrophotographic processes using such a photoreceptor having an insulating layer or a photoreceptor having an insulating layer are 1, for example, U.S. Pat. Publication No. 15446, Special Publication No. 1987-37
Publication No. 13, Special Publication No. 42-23910, Special Publication No. 4
It is described in Japanese Patent Publication No. 3-24748, Japanese Patent Publication No. 19747-1974, Japanese Patent Publication No. 4121-1974, and the like.

The electrophotographic photoreceptor is applied to a predetermined electrophotographic process to form an electrostatic image, and this electrostatic image is developed and visualized.

A typical structure of an image holding member without a photoconductive layer is one having an insulating layer as an image holding layer, and some typical uses of this image holding member include the following.

(1) For example, as described in Japanese Patent Publication No. 32-711, Japanese Patent Publication No. 32-8204, and Japanese Patent Publication No. 43-1559, electronic The electrostatic image formed on the photographic photoreceptor is transferred to an image holding member with a photoconductive layer and developed.
The toner image is then transferred to the recording body.

(2) In addition, as another electrophotographic process in which an electrostatic image is formed on an image holding member without a photoconductive layer in correspondence with an electrostatic image formed on an electrophotographic photoreceptor, for example,
As described in Japanese Patent Publication No. 30320, Japanese Patent Publication No. 48-5063, Japanese Patent Application Laid-Open No. 51-341, etc.5,
An electrostatic image is formed on a screen-shaped electrophotographic photoreceptor having a large number of fine openings by a predetermined electrophotographic process,
By applying corona charging to the image holding member that does not have a photoconductive layer through this electrostatic image, the ion flow of the corona is modulated and an electrostatic image is formed on the image holding member that does not have a photoconductive layer. The final image is formed by developing the image with toner and transferring it to the recording material.

The characteristics of the insulating layer of such an image holding member greatly affect the quality of the image formed, and for this reason, it is extremely important to form a good insulating layer.

The present invention can be applied to the formation of an insulating layer in the image holding member as described above.

In the case of the above-mentioned electrophotographic photoreceptor, the substrate is a support having a photoconductive layer formed on its surface, and in the case of an image holding member without a photoconductive layer, the substrate is a support.

As the cylindrical shrinkable film used in the present invention, a heat-shrinkable film made of polyvinyl chloride, I-lipropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, comb chloride, etc. is suitably used.

Excellent surface lubricity and mechanical strength, resulting in durability and
A heat-shrinkable polyethylene terephthalate film has excellent cleaning properties and corona resistance, as well as moisture resistance and weather resistance.

Further, by forming a resin layer on the surface of the substrate, the adhesion of the insulating layer and the mechanical strength are improved, thereby realizing an improvement in image quality. Examples of resins used for such purposes include comb resins, acrylic resins, -lyester resins, polyamide resins, and cellulose resins.

Next, an outline of the coating method of the present invention will be explained with reference to the drawings.

FIGS. 1(a) and 1(b) are schematic sectional views for explaining one embodiment of the method of the present invention.

In the figure, reference numeral 2 denotes a support for the electrophotographic photoreceptor, which has a cylindrical shape. 4 is a photoconductive layer formed on the surface of the support 2, and 6 is a resin intermediate layer formed on the conductive layer 4. An upper auxiliary cylinder 8 and a lower auxiliary cylinder 1O are attached to both upper and lower ends of the support body 2.

The outer diameters of the upper auxiliary cylinder 8 and the lower auxiliary cylinder 1O are the outer diameters of the cylinder 2 (photoconductive layer 4 and intermediate layer 6f:
The outer diameter (including the outer diameter) is also large. Upper part.

A relatively small hole 8a is formed on the side of the auxiliary cylinder 8 for ventilation, and a lower auxiliary cylinder 10 is formed with a relatively small hole 8a for ventilation.
A ninth opening 10a for introducing pressurized air is formed in the opening 10a.

In the figure, %12 is a cylindrical heat-shrinkable film,
Covers all of the above 2 to 10. The outer diameter of the film 12 when formed into a cylinder is larger than the outer diameter of the auxiliary cylinder 8.10. The upper part of the film 12Fi is sealed in advance by heat shrinkage, heat melting, etc., and its lower edge is sealed in advance by heat shrinkage etc. to the side and bottom surfaces of the lower auxiliary cylinder 10. They are held in close contact.

Further, in the figure, 14a is a water tank for heating, and hot water 16 is accommodated in the water tank 14.

From the arrangement shown in FIG. 1(a), the base body with the shrinkable film 12 torn and the auxiliary cylinders 2 to 10 are moved downward and the whole is immersed in hot water 16.

In this way, the shrinkable film 12 is shrunk by heating with hot water, and the state shown in FIG. 1(b) is reached. FIG. It is. The film is supplied from above in a 12-fold folded state, and is sufficiently expanded by the upper auxiliary cylinder 8 to form a cylindrical shape. Therefore, the film 12 is in the state shown in FIG. 1(&) without contacting the substrate surface.

FIG. 2(b) is a schematic cross-sectional view showing the state of the Fi shrinkable film 12 under heat loss laK. Since the film 12 is supported at both ends by the auxiliary cylinders /-8 and 10, the shrinkage starts from the center and gradually expands to both ends, as shown in FIG. 1(b). Good coverage is achieved.

In addition, the upper part of the side surface of the upper auxiliary cylinder 8 is
Since the film is in a - shape, it is possible to prevent the film from being subjected to sudden force and causing distortion when the film is rolled x2f wide and 1rf, and wrinkle force is generated on the film so that K<.

As described above, by fixing both ends of the cylindrical shrinkable film to the base body and the auxiliary cylinder without leaving much margin in the longitudinal direction, shrinkage in the longitudinal direction is prevented, and thus the The film can be efficiently shrunk in the local direction.

Further, by providing a ventilation hole in the auxiliary cylinder, air can be efficiently vented between the film and the substrate. By providing ventilation holes in both the upper and lower auxiliary cylinders, the efficiency of air removal can be further improved.

In the case where there is no lower auxiliary cylinder and there is only an upper auxiliary cylinder, a similar coating as described above is carried out.

FIG. 3 shows the state of thermal contraction in this case.

Note that the photoconductive layer and the like are omitted in FIG.

〔Example〕

Examples and comparative examples of the present invention, as well as test examples are shown below. Example-1 100 parts of Cd8 powder (M part, the same applies hereinafter) was added with 14 parts of a fluxing agent-soluble vinyl chloride resin as a pine resin. Vinyl acetate copolymer (trade name: VMCH.

UCCH) and 30 parts of methyl ethyl ketone solvent,
Processing by Rollmi/I/ with 80μ gap: 3 times
After recycling, the viscosity was 300epm [1111! ! C, 8
Apply it on an At cylinder of 0φ×≦00 by dipping method,
A photoconductive layer with a thickness of 40 μm was formed by drying at 80° C. for 20 minutes.

Auxiliary cylinders each having a length of 5 cWI were attached to both ends of the cylinder of the base body thus obtained. One of the auxiliary cylinders had an outer diameter of 85 mφ, an end portion of the outer circumferential surface was tapered into a truncated conical shape, and an outer diameter of the tip portion was 60 aNφ.

This auxiliary cylinder has 10 five-inch cylinders arranged at equal intervals in the circumferential direction.
A ventilation hole of φ was provided. The other auxiliary cylinder has an outer diameter of 8
It was 5wφ.

These are covered with 90aNφ shrinkable ester film (
Vertical/horizontal shrinkage rate 20/25 (manufactured by Hoechst),
Both ends were heat-shrinked in advance with hot air at 1,200°C (2/6% shrinkage in length/width), and one end was sealed by heat fusion.

Thus, the state shown in FIG. 2(a)K! After 14t-
As shown in FIG. 1(,), a state was realized in which the first cylinder and the auxiliary cylinder were covered with a shrinkable film.

Next, the shrinkable film was shrunk by immersing it in a hot water bath. Here, the temperature of hot water in the hot water tank #: t95℃
The immersion rate was FiloOx/min.

Next, a portion of the auxiliary cylinder was removed to obtain an electrophotographic photoreceptor having an insulating shell made of a shrinkable film.

Comparative Example-1-1 The same process as Example-1 was carried out, except that in the process of Example-1, an auxiliary cylinder with an outer diameter of 80 mm was used as the auxiliary cylinder having a tapered end. , an electrophotographic photoreceptor was obtained.

Comparative Example 1-21 An electrophotographic photoreceptor was obtained by carrying out the same steps as in 94jai Example 1, except that the auxiliary cylinder was not used during the steps in Example 1.

Test Example-1 - A latent image was formed on the photoreceptor obtained in Example-1 and Comparative Example-1 by primary e-charging, secondary AC static-elimination simultaneous image exposure, and full-surface irradiation, followed by development, transfer, and cleaning. The process
When durable images were produced using a repeating electrophotographic method, no creases or image unevenness due to air entrapment were observed in the photoreceptor obtained in Example 1, and no change in potential characteristics due to heat treatment was observed. However, in the photoreceptor obtained in Comparative Example-1-1, the overall KJll thickness was non-uniform, resulting in significant unevenness of light and shade in the image, and furthermore, a decrease in image density was observed in the portion corresponding to the fold line of the film. The defects were even larger in the photosensitive member obtained in Comparative Example 1-2.

Example 2 In the process of Example 1, cyclized 4-liptadiene with a viscosity of 30 eps diluted with cyclohexane (Nippon Gosei applied 5 ml by dipping method and diluted with cyclohexane for 20 minutes at 80°C).
An electrophotographic photoreceptor was obtained by performing step #i in the same manner as in Example 1, except that an intermediate layer having a thickness of 2 μm was provided by drying for 1 minute.

Comparative Example 2 The same process as in Example 2 was carried out, except that an auxiliary cylinder with an outer diameter of 80 mm was used as the auxiliary cylinder having a chi/IF-shaped end. A friend of the photoreceptor.

Test Example 2 A latent image was formed on the photoreceptor obtained in Example-2 and Comparative Example-2 by primary e-charging, secondary C static-elimination simultaneous image exposure, and full-surface irradiation, and then development, transfer, and rejjjung process. When we produced a durable image using an electrophotographic method that involves repeating the process,
In the photoreceptor obtained in Example-2, no image unevenness due to creases or air entrainment was observed, and no change in potential characteristics due to heat treatment was observed. The image quality was also clear with less roughness, but with the photoreceptor obtained in Comparative Example 2, the shrinkage of the film was incomplete and the film was bent on the cylinder, making it impossible to produce an image. .

[Effect of the invention] According to the method of the present invention as described above, the shrinkable film KFr
Even if there are creases, it is possible to perform a coating without leaving any inconvenient traces caused by the creases and with little deterioration of characteristics, and in particular, when applied to the coating of the substrate of an electrophotographic photoreceptor, it achieves excellent image quality. be able to.

Furthermore, according to the method of the present invention, there are cases where wrinkles occur in the shrinkable film when it is placed on an article, dust, etc. are generated from the film, and v! <Since the film does not come into contact with the article and cause damage, the coating can be carried out without deteriorating the properties or leaving any undesirable traces due to these factors.

Secondly, according to the method of the present invention, coating can be performed simply and at low cost.

[Brief explanation of the drawing]

Figure 1 (a), (b), Figure 2 (m) # (b
) and FIG. 3 are cross-sectional views for explaining the method of the present invention. FIG. 4 is a schematic diagram showing the manufacturability of the cylindrical film. FIGS. 5(a) and 5(b) are cross-sectional views for explaining the conventional coating method. 2 Nijilinda-14: Photoconductive layer, 6: Intermediate layer, 8.10
: Auxiliary cylinder〒, 12: Shrinkable film, 14: Hot water tank. Agent Patent Attorney Minoru Yamashita Hirado Figure 4 Figure 5 (0)

Claims (2)

[Claims] (1) A method of covering a cylindrical article by covering the cylindrical article with a cylindrical shrinkable film and shrinking the film, in which the cylindrical shrinkable film is placed over the cylindrical article and the film is further shrunk. An auxiliary jig having a cylindrical shape corresponding to the cylindrical shape of the article is attached to at least one end of the shaped article, and the auxiliary jig has a radial outer diameter dimension φ_1. φ_3<φ_1<φ_2 between the radial inner diameter dimension φ_2 of the shrinkable film corresponding to the radial outer diameter dimension and the radial outer diameter dimension φ_3 of the article.
A method for covering a cylindrical article with a cylindrical shrinkable film, characterized in that the following relationship holds true: (2) A method for covering a cylindrical article with a cylindrical shrinkable film according to claim 1, wherein the auxiliary jig is integrally formed with the article.