Photography – Fluid-treating apparatus – Having photographic medium feed
Reexamination Certificate
1999-09-28
2001-03-27
Rutledge, D. (Department: 2851)
Photography
Fluid-treating apparatus
Having photographic medium feed
C396S617000, C396S619000, C396S620000
Reexamination Certificate
active
06206587
ABSTRACT:
BACKGROUND OF THE INVENTION
1.Field of the Invention
The present invention relates to an automatic processing machine in which an exposed photosensitive material is subjected to development processing by being sequentially immersed in a developing solution, a fixing solution, and washing water while being nipped and conveyed by a plurality of conveying rollers, and thereafter, the processed photosensitive material is dried in a drying section, and also relates to a method for manufacturing the conveying rollers used in the automatic processing machine.
2.Description of the Related Art
In an automatic processing machine, an exposed photographic photosensitive material (hereinafter referred to simply as a photosensitive material) is subjected to development processing by being conveyed in such a manner as to be sequentially immersed in a developing solution, a fixing solution, and washing water. The photosensitive material having been conveyed through the washing water is dried in a drying section and is discharged from the automatic processing machine.
Here, squeeze rollers are disposed in a crossover portion between adjacent processing tanks in which processing solutions are respectively filled, so as to decrease the amount of processing solutions applied to the photosensitive material in an upstream processing tank and further transferred to a downstream processing tank. Further, squeeze rollers are disposed at the downstream side of a washing tank and are adapted to squeeze out water on the photosensitive material before the photosensitive material is transferred to the drying section.
It is observed that dotted or streaked marks are sometimes formed on the photosensitive material discharged from the automatic processing machine. When such marks are formed on an X-ray film, particularly, there is a possibility that a diagnosis which demands high precision can be interfered. As a result of examining the cause by which such marks or stains occur, it was confirmed that squeeze rollers have a role in causing such marks.
In such conventional squeeze rollers, as is well known, a soft silicon roller having a high water repellency and a hard phenol roller opposed thereto are used.
The water squeezed out by the squeeze rollers may remain between these rollers.
Since the photosensitive material passes through a fixing solution in the development process, fixing components contained in the fixing solution (that is, thiosulfate and the like) are inevitably mixed in the remaining water. The fixing components are dried and concentrated by drying air leaked from the drying section disposed on the downstream side of the squeeze rollers, and remain as spots on the squeeze rollers. As a result, when water is squeezed out from the next conveyed photosensitive material, spot marks are transferred to the material which affect adversely the finished state of an image subjected to development processing.
As measures against the aforementioned, there is a method in which the squeeze rollers are caused to run idle at a predetermined timing to disperse water over the entire surface of the rollers so that water containing fixing components does not remain between the squeeze rollers. However, this method cannot completely prevent the occurrence of the spot marks.
The above-described phenomenon is noticeably seen when relatively new rollers are used, that is, when an almost new automatic processing machine is used, or when rollers are replaced with new ones.
Generally, a silicon roller used as one of the squeeze rollers in an automatic processing machine has a high water repellency, and even if such squeeze rollers are caused to run idle, the surface tension of a water drop keeps the water drop as it is without being dispersed over the entire surface of the one roller, thereby causing formation of spot marks. Accordingly, occurrence of spot marks may be prevented by making the contact angle of a water drop on the roller of the squeeze rollers smaller.
In order for the water to be dispersed on the roller, it suffices that a roller having a high water absorbing ability be employed. However, a roller having a water absorbing surface tends to be contaminated with the passage of time, and therefore, maintenance becomes complicated.
Further, the present inventors have further examined the cause of formation of spot marks, and as a result, they have found that spot marks are formed probably because low molecular weight silicon present in a silicone rubber polymer which is a main component of a silicone rubber roller used as one of the squeeze rollers, volatilizes toward the peripheral surface of the roller and is transferred to the photosensitive material in contact with the squeeze rollers, to thereby cause a the sensitization on the photosensitive material in which the transferred silicon serves as a core thereof.
SUMMARY OF THE INVENTION
In view of the above-described circumstances, it is an object of the present invention to provide an automatic processing machine equipped with a squeeze roller pair which can prevent occurrence of spotted sensitization unevenness on a photosensitive material, and also provide a method for manufacturing a roller used in the automatic processing machine.
In order to achieve the above, in a first aspect of the present invention, there is provided an automatic processing machine in which an exposed photographic photosensitive material is subjected to development processing, comprising: a processing-solution processing section in which the photographic photosensitive material is subjected to development processing in such a manner as to be sequentially immersed in a developing solution filled in a developing tank, a fixing solution filled in a fixing tank, and washing water filled in a washing tank; a drying section in which the photographic photosensitive material processed in said processing-solution processing section is subjected to drying processing; and at least one conveying roller pair which is disposed at any one of a crossover portion between the developing tank and the fixing tank, and a position between the washing tank and said drying section, wherein a roller of the conveying roller pair, which comes into contact with a photosensitive emulsion surface of the photosensitive material, is structured in such a manner that a contact angle of a water drop on a peripheral surface of the roller is less than 135°.
According to the first aspect of the present invention, after development and washing processings, the contact angle of a water drop with respect to the peripheral surface of the roller of the conveying roller pair becomes smaller than 135°. The contact angle is more preferably less than 125°. When the contact angle becomes smaller, the surface tension of the water drop itself is weakened and water is dispersed over the roller peripheral surface. Accordingly, even when roller surfaces of the conveying roller pair are apt to be dried under the influence of the drying section disposed directly downstream of the conveying roller pair, adverse effects (spotted sensitization unevenness and the like) on a photosensitive material subsequently conveyed, which are caused by a concentration of components of a fixing solution contained in the water drops remaining on the roller peripheral surface, are remarkably alleviated.
In a second aspect of the present invention, in a surface treatment for a roller which comes into contact with an emulsion surface of the photosensitive material, the roller is immersed in an aqueous solution containing gelatin so that a surface thereof is coated with gelatin. At this time, it is most suitable that the roller is immersed in an aqueous solution containing 1 wt % of gelatin having a molecular weight of 20,000 to 300,000 and an average molecular weight of 100,000 so as to be coated with a gelatin film.
According to this aspect of the present invention, due to the roller being coated with the gelatin film, the contact angle of the water drop can be set at 125°. Therefore, the surface tension of the water drop is restrained and a so-called
Ikeda Jun
Inoue Kenji
Mizuma Yutaka
Fuji Photo Film Co. , Ltd.
Rutledge D.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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