APPARATUS FOR THERMALLY FIXING A NON-SILVER FREE RADICAL PHOTOSENSITIVE COMPOSITION
United States Patent 3727534
The heat fixing of non-silver free radical films is effected by blowing heated air directly at the film so that the air strikes the film approximately perpendicular to the film surface and a turbulence is created in the air adjacent to the film and the apparatus for effecting the same.
US Patent References:
PROCESS AND APPARATUS FOR THE DEVELOPMENT OF PHOTOCOPYING MATERIAL
Endermann et al. - April 1969 - 3440944
APPARATUS FOR DEVELOPING AND FIXING A THERMODEVELOPABLE PHOTOGRAPHIC MEDIUM
Berg - March 1971 - 3570383
PROCESS AND APPARATUS FOR THE DEVELOPMENT OF PHOTOCOPYING MATERIAL
Endermann et al. - April 1969 - 3440944
APPARATUS FOR DEVELOPING AND FIXING A THERMODEVELOPABLE PHOTOGRAPHIC MEDIUM
Berg - March 1971 - 3570383
Inventors:
Low Jr., William H. (Shaker Heights, OH)
Schaller, David R. (Chagrin Falls, OH)
Schaller, David R. (Chagrin Falls, OH)
Application Number:
05/190720
Publication Date:
04/17/1973
Filing Date:
10/20/1971
View Patent Images:
Export Citation:
Assignee:
Horizons Incorporated, a Division of Horizons Research Incorporated (Cleveland, OH)
Primary Class:
Other Classes:
396/564
International Classes:
G03D15/02
Field of Search:
95/89R,89G,94G 34/151,219
Primary Examiner:
Matthews, Samuel S.
Assistant Examiner:
Braun, Fred L.
Claims:
We claim
1. An apparatus for thermally fixing a non-silver, free radical photosensitive film which comprises:
2. The apparatus of claim 1 including means adjacent to the inlet to said plenum chamber to filter the air entering said chamber.
1. An apparatus for thermally fixing a non-silver, free radical photosensitive film which comprises:
2. The apparatus of claim 1 including means adjacent to the inlet to said plenum chamber to filter the air entering said chamber.
Description:
This invention relates to an improvement in the thermal fixing of non-silver free radical photosensitive compositions of the type described in U.S. Pat. No. 3,042,515 and improvements thereon, e.g. those described in many of the patents listed in U.S. Pat. Nos. 3,493,376 and 3,510,304, for example.
The compositions in said patents include in many instances as a source of free radicals, an organic halogen compound such as iodoform or carbon tetrabromide or other organic compounds of similar structure along with a color forming compound, usually an organic amine which may be a dye or color former. During the thermal fixing steps these compounds tend to vaporize and leave the film,and heating accentuates this tendency.
In the past, fixing of such films has been accomplished by placing the film in a forced air oven, the film being disposed so that hot air has been caused to flow across the surface of the film. The flow of air swept away any vapor of organic halogen compound and other compounds evolved and leaves a photographically "fixed" film.
The laminar flow of air over the film surface is often uneven and results in uneven heating of the film. As a consequence the film may be completely fixed in one area and only partially fixed in an adjacent area. Furthermore, some of the thermal energy applied to fix the film may serve to develop or intensify the image in the film or to fog the film. In addition, the evolved compounds often are picked up by the film and produce false images.
In an effort to obviate these difficulties, the present invention is directed to an apparatus and process for applying a turbulent blanket of heated air to one side of a non-silver free radical photosensitive film to produce a more uniform fixing than has been achieved in the past.
The invention will be more clearly understood from the description which follows taken in conjunction with the drawings in which:
FIG. 1 is a view partly in section of one apparatus for practicing this invention; and,
FIG. 2 is a view in perspective, showing the manner in which the heated air makes contact with the photosensitive film being fixed.
One suitable apparatus shown in FIG. 1 comprises a housing 10, having an air inlet 12 and an air outlet 14. An air filter 16 guards the inlet and the air which passes through the apparatus and into plenum chamber 20 by a blower 18. The air is heated by a heater 22 positioned adjacent to the blower outlet 24 and soon fills the plenum chamber and raises the pressure therein so that the heated air seeks an exit. Such an exit is shown in the form of an open window at 26, from which the air moves toward the film surface F which the air strikes approximately perpendicular to the film surface, and is reflected back into the plenum chamber in which it creates a turbulence 30. Some air passes out through the narrow space between the window of the plenum chamber and the film surface.
Air leaving the area is caused to traverse a charcoal filter 40 in which any pollutants are absorbed and then passes to the outlet passage 42 of the housing. A damper 44 may be used to selectively deflect the air to an exhaust port or to the blower inlet 46. It will be seen that the above described apparatus provides a turbulent zone of heated air adjacent to the surface of the film to be fixed and prevents redeposition of any of the compounds released by said film when it is heated.
Optionally the blower-heater may be two separate units, one of which blows (pushes) or sucks (pulls) air into the plenum chamber and the other of which heats the air.
Other optional features include a filter at the blower intake, a thermostat for checking the air temperature and activating the heater, and means to collect the air exiting from the region of the film, and to pass it through a filter or absorbent means so that the materials evolved from the photosensitive film do not escape to pollute the atmosphere and an outlet from which the air is vented to the atmosphere or recirculated to the blower-heater.
The compositions in said patents include in many instances as a source of free radicals, an organic halogen compound such as iodoform or carbon tetrabromide or other organic compounds of similar structure along with a color forming compound, usually an organic amine which may be a dye or color former. During the thermal fixing steps these compounds tend to vaporize and leave the film,and heating accentuates this tendency.
In the past, fixing of such films has been accomplished by placing the film in a forced air oven, the film being disposed so that hot air has been caused to flow across the surface of the film. The flow of air swept away any vapor of organic halogen compound and other compounds evolved and leaves a photographically "fixed" film.
The laminar flow of air over the film surface is often uneven and results in uneven heating of the film. As a consequence the film may be completely fixed in one area and only partially fixed in an adjacent area. Furthermore, some of the thermal energy applied to fix the film may serve to develop or intensify the image in the film or to fog the film. In addition, the evolved compounds often are picked up by the film and produce false images.
In an effort to obviate these difficulties, the present invention is directed to an apparatus and process for applying a turbulent blanket of heated air to one side of a non-silver free radical photosensitive film to produce a more uniform fixing than has been achieved in the past.
The invention will be more clearly understood from the description which follows taken in conjunction with the drawings in which:
FIG. 1 is a view partly in section of one apparatus for practicing this invention; and,
FIG. 2 is a view in perspective, showing the manner in which the heated air makes contact with the photosensitive film being fixed.
One suitable apparatus shown in FIG. 1 comprises a housing 10, having an air inlet 12 and an air outlet 14. An air filter 16 guards the inlet and the air which passes through the apparatus and into plenum chamber 20 by a blower 18. The air is heated by a heater 22 positioned adjacent to the blower outlet 24 and soon fills the plenum chamber and raises the pressure therein so that the heated air seeks an exit. Such an exit is shown in the form of an open window at 26, from which the air moves toward the film surface F which the air strikes approximately perpendicular to the film surface, and is reflected back into the plenum chamber in which it creates a turbulence 30. Some air passes out through the narrow space between the window of the plenum chamber and the film surface.
Air leaving the area is caused to traverse a charcoal filter 40 in which any pollutants are absorbed and then passes to the outlet passage 42 of the housing. A damper 44 may be used to selectively deflect the air to an exhaust port or to the blower inlet 46. It will be seen that the above described apparatus provides a turbulent zone of heated air adjacent to the surface of the film to be fixed and prevents redeposition of any of the compounds released by said film when it is heated.
Optionally the blower-heater may be two separate units, one of which blows (pushes) or sucks (pulls) air into the plenum chamber and the other of which heats the air.
Other optional features include a filter at the blower intake, a thermostat for checking the air temperature and activating the heater, and means to collect the air exiting from the region of the film, and to pass it through a filter or absorbent means so that the materials evolved from the photosensitive film do not escape to pollute the atmosphere and an outlet from which the air is vented to the atmosphere or recirculated to the blower-heater.