US2548824A

US2548824A - Photographic drier

Info

Publication number: US2548824A
Application number: US22761A
Authority: US
Inventors: Sauter Oscar William
Original assignee: H I THOMPSON Co
Current assignee: H I THOMPSON Co
Priority date: 1948-04-23
Filing date: 1948-04-23
Publication date: 1951-04-10
Anticipated expiration: 1968-04-10

Description

April 10, 1951 I w SAUTER 2,548,824

IIHOTOGRAPHIC DRIER Filed April 23, 1948 Ifgi. d

IN VEN TOR.

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Fatented Apr. 10, 1951 PHOTOGRAPHIC DRIER Oscar William Sauter, Glendale, Calif., assignor to The H. I. Thompson Company, Los Angeles, Calif., a corporation of California Application April 23, 1948, Serial No. 22,761

3 Claims.

This invention relates to improvements in the construction of driers for photographic prints.

Qne form of drier employs an endless belt which passes over a rotatable heated drum. The prints are placed between the belt and the drum and as the belt travels over the drum the prints are brought into contact with the heated drum and thus heated.

In such operations, the moisture must be removed from the surface of the paper and caused to evaporate through the belt. It is most important to prevent accumulation of water between the print and the belt. The evaporation of such moisture from a droplet of water held between the print and the belt will cause blistering of the print.

The prior art attempted to solve these two requirements of porous belt and prevention of accumulation of water droplets between the belt and the print by the following expedients: The

belt was made porous and water absorbent by employing a belt formed of woven straw matting covered with light canvas. It was found necessary in order to minimize the possibility of blistering that care be used to drain the washed prints thoroughly, and when excessively wet they must be pre-dried between blotters before placing them on the belt.

Such belts readily became soiled and stiii .due to the accumulation of salts resulting from the evaporation of the water, which salts are the results of the developer not completely removed by washing. The salts also attack the belt chemically and weaken and impair its utility. The belt must therefore be frequently replaced. In some busy laboratories this may be as often as twice a day.

Additionally. the belts become charred and burn if the drier is stopped while the drum is hot. In shutting down the machinery the heating element mounted in association with the drum must first be shut off and the machine run until the drum cools down. This takes at least ten to fifteen minutes. It also takes an equal time to heat the drum again.

The above considerations also limit the temperature at which the drum must be operated and the tension which it is permissible to place on the belt. The belt is of such mechanical construction that it may not be placed in high tension and since it is usually soon stiff with salts and impaired in quality it may not be stressed too greatly. Additionally, it becomes saturated with moisture and becomes slack. Because of the limitation in tension and the limitations in the permissible temperature, it is frequently necessary to run prints through twice to completely dry and iron them flat.

I have discovered that I may obviate all of these difficulties by replacing such prior art belts with a belt formed of woven glass fibers suitably prepared for this service.

Such woven glass fibers do not have the disadvantages of the prior art belts. ,They are porous and non-absorbent. The moisture is completely evaporated from the belt. The belt is not attacked by the salts and may be readily washed to remove salt incrustations and to keep it clean and porous without removing the belt from the machine. It is resistant to high temperatures and is not inflammable or in any way aiiected by heat much higher than the boiling point of water and has a high tensile strength.

Because of these properties this machine may be operated at a higher belt tension and higher temperature than with the prior art belts, and at a higher speed. Because of the higher temperature and tension, the prints may be passed through but once at even a higher speed and dry flat and produce prints which are dry and flat. This increases the capacity of the machine.

It is unnecessary to replace belts, since the belts can be kept clean by simply washing them on the machine, and since they are not attacked by the salts. Whereas the average life of the belts of the prior art are from one week to half a day, depending on the service, one belt of my invention has been in service for eight months without removal from the machine and without any visible signs of wear or deterioration. Additionally, it is not necessary to allow the machine to cool down before stopping the belt. It is possible to stop the belt while the heat is on the drum. This cuts down the down-time required to cool and reheat the drum and increases production. An important consideration is that there is no fire hazard. With the prior art belts, if the belt is stopped before the drum cools down, the belt may catch on fire-an accident which has happened with sufiicient frequency to make the prior art belt a fire hazard.

I have thus found that by substituting a belt of my construction for the prior art belt, I have:

(a) Increased the productive capacity of the machine; J

(b) Avoided the necessity for frequent replacement of the belt;

(c) Made possible the drying and ironing of the prints in a single pass instead of two passes;

Fig. 5 is a section taken on line 5-5 of Fig. 3.

The drum support 2 positioned on each side of the drum 3 is mounted on base I. The drum 3 is mounted, on trunnions and stub shaft 4, in support 2. The drum is hollow and heater 5, which may be an electrical resistance heater or a gas flame, is mounted through one of the trunnions 4 and suitably connected to a current source or a gas line as the case may be. Mounted on support 2 are the idler belt shafts 6, l, and 8. A shaft 9 is also mounted on the support 2. Each of the shafts 6, l, 8, and 9 carries a sprocket over which the sprocket chain [9 is passed. The shaft 9 is driven through gear box I3, pulley and belt assembly 12 by the motor ll.

Mounted in base I is an extension bracket lila. Idler shafts l5 and I6 are mounted on the extension !3a and idler shaft I4 is mounted on the base I. Mounted on the support 2 is a receiving pan I1 and a plate 18. A belt I9 is threaded over

shafts

6, 1, 8 and 15. The belt extends to form a substantiaily horizontal section or apron extending from the shaft i5 and becoming tangent to the drum, passing over the drum and underneath shafts 9, l9, and I4 and over the drum 3.

In order to dry and iron the prints, the prints are laid on the belt (but not at the point shown in Fig. 3) in front of the pan l1 and as the belt travels the prints pass between the belt and the heated drum and are picked up by the blade 49 and deposited in the pan 11.

In the drier of my invention I employ a belt of woven glass fiber, preferably woven with a crows foot pattern. The belt is coated for a distance of about one inch on both sides of the belt at 29 and 2i at the selvedge edges and at 22 of each of the cut edges of the strip 23 which is to be formed into the belt. The glass cloth is acid resistant (except to hot phosphoric and hydrofiuoric acids) and is non-hygroscopic and will not stretch nor shrink due to wetting and drying and will resist temperature far in excess of the maximum temperature attained in the drier.

I may employ dry adhesive coating such as rubber latex or any elastomer latex such as the iii) 12 ounce canvas strip 24, folded over on each end and sewn with a synthetic fiber such as that of the polyamine type in four separate seams 24a; and joined together with a waxed cord 25 by means of a baseball stitch. In using the belt it is desirable not to place the prints at the joint, nor to stop the machine with the joint next to the drum.

While I have described a particular embodiment of my invention for the purpose of illustration, it should be understood that various modifications and adaptations thereof may be made within the spirit of the invention as set forth in the appended claims.

I claim:

1. A belt formed of a strip of woven glass fibers having an outer glass fiber surface and selvedge edges and cut edges, each of said edges being adhesively coated with a dry adhesive, the coated out edges beingcovered with light canvas and joined by a thread stitch at said edges into an endless belt.

2. A drier for photographic film comprising a drum, means for heating said drum, a standard upon which said drum is rotatably mounted, a base for said standard, a plurality of belt shafts on said base and standard, a belt formed of a strip of woven glass fibers having selvedge edges and cut edges, each of said edges being adhesively coated with a dry adhesive, the coated cut edges being covered with light canvas and joined by a thread stitch at said edges into an endless belt, and threaded over said shafts to form a horizontal belt upon and passing tangent to said drum and over said drum, means for moving said belt over said drum, and means for rotating said drum.

3. A drier for photographic film comprising a drum, means for heating said drum, a standard upon which said drum is rotatably mounted, a base for said standard, a plurality of belt shafts on said base and standard, an endless belt formed of a strip of woven glass fibers, said belt having an outer glass fiber surface and selvedge edges, said selvedge edges being coated with dry adhesive, said belt being threaded over said shafts and said belt passing over said drum; and means for moving said belt over said drum and for rotating said drum.

0. WILLIAM SAUTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 355,766 Kenyon Jan. 11, 1887 1,384,125 Dye July 12, 1921 1,635,185 Kimmich July 12, 192'? 1,944,600 Greene Jan. 23, 1934 2,135,057 Slayter et a1 Nov. 1, 1938 2,179,691 Freedlander Nov. 14, 1939 2,360,257 Muller et a1 Oct. 10, 1944 2,446,294 Mitchell Aug. 3, 1948