Coating processes – Application to opposite sides of sheet – web – or strip
Patent
1983-06-23
1985-10-22
Beck, Shrive P.
Coating processes
Application to opposite sides of sheet, web, or strip
427420, 427402, 118 62, 118410, 118411, B05D 126, B05D 130
Patent
active
045488371
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates to a method and an apparatus for coating supports in the floated state. More specifically, this invention relates to a method and an apparatus for applying one or more coating solution on supports such as photosensitive materials which run continuously, while supporting the surface thereof opposite to the coated surface in a contactless manner, and particularly to a method and an apparatus for coating which are suitable to perform both-side coating continuously.
2. Background Art
Heretofore, photosensitive materials having coated layers on both sides of supports have been manufactured as follows. A coating solution is applied on either one side of the support, and the applied coating is gelatinized and dried. Thereafter, the support is passed through the same process to apply, gelatinize and dry a coating solution on the other side thereof. But, to meet a demand for improving production efficiency, there have been proposed various kinds of both-side coating methods with which coating layers are formed on both sides of the support by passing it through the coating and drying process just one time. As one of those methods, there is known such a method that one side of the support is first coated and gelatinized and then its opposite side is coated successively. This method is mainly divided into the following two groups. (I) A method as shown in Japanese Patent Publication No. 44,171/1973, in which one side of the support is first coated and gelatinized, and then its opposite side is coated while bringing the gelatinized side into contact with a supporting roll directly, and (II) a method as shown in Japanese Patent Publication No. 17,853/1974 or No. 38,737/1976, in which gas is jetted from the surface of a supporting roll (i.e., gas injector) having a certain curvature and hence the support is floated, thereby to coat the opposite side in such floated state. The method (I) has disadvantages as follows. If the surface of the supporting roll includes cracks or dusts thereon even to a small extent, this results in a coating failure directly. Thus, maintenance is very difficult. Even if there exists no crack or dust, the coated layer is disturbed when the portion of the support having variation in a thickness of the coated film, such as a beginning portion of coating and a spliced portion, passes the supporting roll while coming into contact therewith, whereby a part of the coated layer adheres onto the roll and this further disturbs the subsequent coated layer. Also, the method (II) is accompanied with such a disadvantage that coating uneveness in the form of horizontal steps tends to generate due to minute fluctuations in floated distance (i.e., lift) of the support which is caused by variation in a tensile force of the support to be coated. Particularly, in the method such that gas is jetted from the curved surface of the roll having small holes and slits to float the coated support and the leading end of an applicator is pressed onto the surface of the support for coating, as disclosed in Japanese Patent Publication No. 17,853/1974, the aforesaid undesirous tendency appears in the end portions of the support remarkably. Meanwhile, in the apparatus such that a roll for supporting both side edges of the support is provided to float and coat the support, as disclosed in Japanese Patent Publication No. 38,737/1976, the aforesaid tendency is increased in the center and in the vicinity thereof of the coated support.
DISCLOSURE OF INVENTION
Therefore, it is an object of this invention to eliminate the disadvantages as mentioned above and to provide a method and an apparatus with which the support to be coated is supported by a gas injector in a contactless manner with the floated distance (i.e., lift) being reduced to permit uniform coating on the opposite side, and thereby to provide a method and an apparatus for coating which permits to coat both sides of the support continuously.
Other objects of this invention will be apparent from the following explana
REFERENCES:
patent: 3065098 (1962-11-01), Brooks
patent: 3496005 (1970-02-01), Ishiwata et al.
patent: 4241111 (1980-12-01), Hamamura et al.
Kageyama Takashi
Kato Kazuo
Kishido Takeshi
Yoshino Tetsuya
Beck Shrive P.
Kirby Thomas F.
Konishiroku Photo Industry Co,., Ltd.
Nilles James E.
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