HEAT PROCESSOR FOR PHOTOGRAPHIC FILMS
United States Patent 3798790
In apparatus for processing photographic ribbon film that has a photosensitive coating on one side which is developed and fixed by heat, the film is moved along a spiral path through a heat chamber which accommodates a long length of film in a relatively small space, and in a manner such that the coated side of the film does not come in contact with any support surface. Heat is applied to the coating in a uniform manner by jets of hot air from nozzles spaced along the path of the film. The jets of hot air impinge on the coated side of the film at an acute angle and the nozzles are spaced so that the hot air sweeping over the coating carries the effluent gases, which are released by the developing photosensitive material, away from the coated surface of the film and into streams of exhaust gases which flow along in back of the nozzles to an exhaust port. The film is drawn from the heat chamber, out and through an adjacent cooling chamber prior to its collection on a take up reel. An exhaust port in the cooling chamber serves to draw cool clean outside air through the cooling chamber to cool the film. The heat chamber and cooling chamber exhaust ports straddle the film exit opening from the heat chamber to the cooling chamber and prevent the air from one chamber from contaminating the other chamber.
US Patent References:
Method of cleaning and drying strip or sheets
Quigley - September 1941 - 2255859
Tape drying system
Carter - December 1949 - 2491714
Method and apparatus for drying printed silk screened articles
Daley - November 1968 - 3411217
Combination preheater and steam shower for corrugating and like machines
Carder - June 1946 - 2402237
/3358384.html
Gustafsson et al. - December 1967 - 3358384
Method of cleaning and drying strip or sheets
Quigley - September 1941 - 2255859
Tape drying system
Carter - December 1949 - 2491714
Method and apparatus for drying printed silk screened articles
Daley - November 1968 - 3411217
Combination preheater and steam shower for corrugating and like machines
Carder - June 1946 - 2402237
/3358384.html
Gustafsson et al. - December 1967 - 3358384
Application Number:
05/321011
Publication Date:
03/26/1974
Filing Date:
01/04/1973
View Patent Images:
Export Citation:
Assignee:
The Perkin-Elmer Corporation (Norwalk, CT)
Primary Class:
Other Classes:
34/66
International Classes:
G03D13/00; F26B13/00
Field of Search:
34/6,23,24,62,66,67,151,152,155,158-161
Primary Examiner:
Camby, John J.
Attorney, Agent or Firm:
Conant, John K.
Claims:
What is claimed is
1. Apparatus for processing ribbon film which has on one side a photosensitive material that is developed and fixed by heating, comprising,
2. The apparatus of claim 1 in which the constricted openings in said nozzle elements are small generally circular holes for producing outwardly diverging conical jets of air therefrom, the holes being spaced so that the conical jets from adjacent holes overlap prior to their impingement on the adjacent portion of a film on said path.
3. The apparatus of claim 1 in which said heating chamber is an annulus defining a central compartment, said entrance opening of the chamber opening into said compartment, and including means for mounting a supply reel of said film in said compartment in position to feed film from a supply reel on the mounting means into the chamber through the entrance opening, means mounting a take up reel for said film outside the chamber in position for thereon film emerging from said exit opening in the chamber, first power drive means for rotating a supply reel of film on said mounting means therefor, second power drive means for rotating a take up reel on said mounting means therefor, and first and second feeler gauge means engaging said supply and take up reels, respectively, for controlling the speed and tension of a film moving from said supply reel to said take up reel.
4. The apparatus of claim 3 including a cooling chamber adjacent the exit opening in the heating chamber and enclosing at least a portion of said predetermined path of a film from the heating chamber exit opening to a take up reel on the mounting means therefor, an exhaust port opening into said cooling chamber adjacent said exit opening of the heating chamber, said cooling chamber being defined by walls having vents therethrough, for surrounding air to enter, said vents being located downstream along the path of a film through said cooling chamber from said exit opening of the heating chamber, and means to apply negative air pressure at said exhaust port opening into the cooling chamber for circulating air through the cooling chamber from said vents to said exhaust port in a direction opposite the direction of movement of a film through the cooling chamber.
1. Apparatus for processing ribbon film which has on one side a photosensitive material that is developed and fixed by heating, comprising,
2. The apparatus of claim 1 in which the constricted openings in said nozzle elements are small generally circular holes for producing outwardly diverging conical jets of air therefrom, the holes being spaced so that the conical jets from adjacent holes overlap prior to their impingement on the adjacent portion of a film on said path.
3. The apparatus of claim 1 in which said heating chamber is an annulus defining a central compartment, said entrance opening of the chamber opening into said compartment, and including means for mounting a supply reel of said film in said compartment in position to feed film from a supply reel on the mounting means into the chamber through the entrance opening, means mounting a take up reel for said film outside the chamber in position for thereon film emerging from said exit opening in the chamber, first power drive means for rotating a supply reel of film on said mounting means therefor, second power drive means for rotating a take up reel on said mounting means therefor, and first and second feeler gauge means engaging said supply and take up reels, respectively, for controlling the speed and tension of a film moving from said supply reel to said take up reel.
4. The apparatus of claim 3 including a cooling chamber adjacent the exit opening in the heating chamber and enclosing at least a portion of said predetermined path of a film from the heating chamber exit opening to a take up reel on the mounting means therefor, an exhaust port opening into said cooling chamber adjacent said exit opening of the heating chamber, said cooling chamber being defined by walls having vents therethrough, for surrounding air to enter, said vents being located downstream along the path of a film through said cooling chamber from said exit opening of the heating chamber, and means to apply negative air pressure at said exhaust port opening into the cooling chamber for circulating air through the cooling chamber from said vents to said exhaust port in a direction opposite the direction of movement of a film through the cooling chamber.
Description:
BACKGROUND OF THE INVENTION
The present invention relates to apparatus for processing photographic film of the type in which a latent image previously formed in a photosensitive coating on the film is developed and fixed by heat. In particular the invention is relatively compact apparatus for rapidly and effectively heat processing long strips or ribbons of such film.
In general, the subject film is developed and fixed by heating it to a particular temperature for a specified time and then cooling it. The problems involved in thus processing it are that when heated, the photosensitive coating, which is on one side of the film, is soft and easily scratched or marred so that the coated side must be kept out of contact with other surfaces, and the heating must be uniform or else the image density will vary. Also, as the photosensitive material develops and is fixed by heat, it gives off gases which must be removed quickly from the vicinity of the coating so as not to fog the developing images.
In known prototype apparatus for heat processing long lengths of film of the subject type, the film from a supply reel is drawn in a straight line through an elongated heat chamber out through a cooling chamber or through a span of open air to a take up reel. A principal problem with this known heat processing apparatus is that the effluent gases from the heated film tend to circulate back in contact with the film and cause fogging. Also, eddy currents produced in the stream of hot air traveling through the heating chamber cause variations in the temperature rise of the film at different areas of the film which result in variations in the image density.
BRIEF DESCRIPTION OF THE INVENTION
A principal object of the present invention is to provide apparatus for heat processing film of the subject type that assures even heating of the film and effective removal of the effluent gases so that the problems of variations in image density and fogging of the film are avoided, and to provide such apparatus which is more compact so as to be accommodated in less horizontal and/or vertical space than previous apparatus for the same purpose.
In accordance with the invention the heat chamber is an annular chamber separated from a compartment in the center of the annulus. Film from a supply reel mounted in the center compartment is fed into the heat chamber through which it moves along a spiral path, defined by support rollers, to an exit into a cooling chamber and through the cooling chamber to a take up reel. The spiral path of the film through the heating chamber is such that only the uncoated non-sensitive side of the film comes in contact with support rollers which define the path.
Heat for processing the film in the heat chamber is applied by jets of hot air from a plurality of nozzles spaced along the spiral path of the film and arranged so that the jets of hot air impinge on the photosensitive coating of the film at an acute angle so that the hot air sweeps or scrubs the film, sweeping the effluent gases away from the coated surface and out between adjacent nozzles into an exhaust stream of gases which flows back of the nozzles to an exhaust port. The hot air jets thus serve the dual functions of applying heat uniformly to the film and of immediately carrying the effluent gases away from the film.
The exhaust port for drawing effluent gases from the heat chamber, and an exhaust port in the cooling chamber, for drawing cool outside air therethrough, are adjacent to the film exit from the heat chamber to the cooling chamber and cooperate to prevent air from one chamber from contaminating the air in the other.
In addition to the advantages of the apparatus of this invention indicated above, the structure is such that the apparatus can be built for processing film of varying size, from 35mm to 91/2 inch wide film, without having to substitute parts.
Further objects, advantages and features of the apparatus of this invention will be apparent from the following more detailed description of an illustrative embodiment shown in the accompanying drawings, in which:
FIG. 1 is a front elevational view of film heat processing apparatus of this invention;
FIG. 2 is an enlarged front view partly in section of the apparatus of FIG. 1;
FIG. 3 is a section along the line 3--3 of FIG. 2;
FIG. 4 is a rear elevational view of the apparatus shown in FIG. 1;
FIG. 5 is a section along the line 5--5 of FIG. 3; and
FIG. 6 is an enlarged end view of an adjacent pair of the nozzles in the heat chamber, showing the jets of air flowing out from the nozzles.
Referring to FIGS. 1 and 2 of the drawings, the film heat processing apparatus of this invention includes an annular heating chamber 10 having inner side walls 11 and 12 and inner top and bottom walls 13 and 14 defining a central compartment 15 and outer side walls 16 and 17 and outer top and bottom walls 18 and 19. The front of the chamber 10 is closed by a pair of doors 20 which are each shaped like a U on its side so as to leave the central compartment 15 open to the front and rear when the doors are closed. The doors open to expose the interior of the heat chamber 10 for cleaning and for initially threading a film therethrough; it also provides access to the film in the chamber, to repair a break in the film, for example. The back of the heat chamber 10 is closed by a back wall 21 (FIGS. 3 and 4).
A supply of heat processable film 22 is provided on a supply reel 23 supported on a spindle 24 in the compartment 15. From the supply reel 23 the film feeds over an idler roller 25 and thence into the heat chamber 10 through an entrance opening 26 through the chamber side wall 11. The spindle 24 is driven by conventional drive connections to a variable speed motor 27. The speed of the motor 27 and thus the rotation of the supply reel 23 is adjusted over a predetermined range of speeds by means of conventional speed control mechanism. A feeler arm 28 resting on the roll of film 22 on the reel 23 measures the amount of film on the reel and provides a signal to the motor speed control mechanism to assure constant film speed. A conventional limit switch (not shown) is provided to shut off the apparatus (i.e., motors 27 and 53) when the film supply reel 23 is nearly empty.
Also in the compartment 15 is a conventional film clamping, cutting and splicing unit 29, which straddles the run of film 22 between the idler roller 25 and the entrance opening 26 to the heating chamber to be used for attaching the lead end of a supply of film 22 to a leader film strip (not shown) which is threaded through the apparatus and attached to a take up reel for leading film 22 through the apparatus at the start of a processing operation.
Film 22 entering the heat chamber 10 from the entrance opening 26 moves along successive convolutions of a spiral path formed by idler rollers 30a, b, c and d, which define the innermost convolution of the spiral, and idler rollers 30e, f, g and h, which define the outermost convolution. Between the idler rollers 30g and 30h the film passes out of the heat chamber through an exit opening 31 into a cooling chamber 32 in which the idler roller 30h is mounted. As shown, the film 22 passes around the successive rollers 30a to 30h so that only the inward side of the film 22 comes in contact with the roller surfaces. Thus the outward side of the film 22, which will be the sensitive side, does not come in contact with any surface while the film 22 is in the heating chamber 10.
Heat is applied to photographic material on the outward side of film 22 moving through the heating chamber 10 by means of nozzles 34 which are mounted at spaced intervals along the path of a film 22 through the heating chamber to be adjacent the outward sensitive side of film moving along the path. As best seen in FIGS. 3 and 5, the nozzles 34 are elongated, hollow tubular elements mounted on the back wall 21 of the heating chamber to extend across the width of photosensitive material 35 on a film 22 moving along the aforesaid path. The interior of each nozzle 34 opens through the wall 21 into a plenum chamber 36 which is back of the heating chamber 10, and which supplies hot air under pressure to the nozzles. The other ends of the nozzle elements 34 are closed and a plurality of holes or other openings 37 through the sides of the nozzles direct jets 38 of the hot air under pressure, out of the nozzles to impinge on a film 22 on the path through the chamber.
Referring to FIGS. 3 and 4, hot air under pressure is supplied to the plenum chamber 36 by a motor driven fan 40 and a heating unit 41 mounted in an inlet conduit 42 which opens into the plenum chamber 36 at one end and to the outside air at the other. The fan 40 draws outside air into the conduit 42 and blows it through the heating unit 41 into the plenum chamber 36.
As best in FIGS. 2, 5 and 6, the holes 37 in the nozzles 34 are arranged so that the jets 38 of hot air impinge on the photosensitive coating 35 of film 22 at an acute angle. The air forming the jets 38 diverges as it emerges from the holes 37 so that the jets are conical in shape, and the holes 37 are spaced so that the cones overlap prior to reaching the area of impingement. The hot air jets 38 of each nozzle 34 thus provide a lateral band of hot air impinging on the photosensitive coating 35 in a continuous band across the width of the layer of photosensitive coating.
As illustrated in FIGS. 2 and 6, the nozzles 34 are spaced apart and arranged along the path of a film 22 so that the hot air jets 38 impinge on the photosensitive coating 35 on the film at an acute angle and, from the direction in which the film is moving so that the direction of impingement of the jets 38 on the film is opposite the direction of film movement, thereby producing a good scrubbing action. The jets 38 of hot air thus sweep and scrub the photosensitive coating 35 on the film, and then deflect and circulate outward between adjacent nozzles and into exhaust streams of the hot air and effluent gases from the heated photosensitive film coating. These exhaust streams, as indicated by arrows 44 and 45, flow back of the outward sides of the nozzles 34. These exhaust streams flow along flow paths provided by the spacing of the nozzles 34 from the adjacent path of the film and from the outer walls 16, 17, 18 and 19 of the heating chamber; the exhaust flow is initiated and maintained by a combination of the positive pressure provided by the hot air jets 38 as deflected by the film 22 and a negative pressure applied at an exhaust port 46 which opens across a major portion of the annular width of the chamber 10 through a portion of the back wall 21 adjacent the film exit opening 31. The hot air jets 38 thus not only heat the photosensitive coating 35 on film 22 but also carry off the effluent gases generated by the heat developing and fixing process into exhaust streams that carry the effluent gases from the chamber in a manner which prevents the effluent gases from coming in contact with the photosensitive coating.
Referring to FIG. 3, an exhaust conduit 47 is provided at the back of the apparatus and the exhaust port 46 of the heat chamber 10 (as well as an exhaust port 58 from a cooling chamber 32, subsequently described) opens into the exhaust conduit 47. The other end of the exhaust conduit 47 opens to the air, suitably outside the building in which the apparatus is located and negative pressure is created at the exhaust port 46, and at cooling chamber exhaust port, for assisting the exhausting of the effluent gases by suitable means such as a motor driven exhaust fan indicated at 48 in the exhaust conduit 47. It will usually be desirable to filter the exhaust gases as they leave the apparatus by suitable means, such as a charcoal filter 49 shown in the conduit 47, to remove any noxious materials from the exhaust gas.
As previously mentioned, film 22 exiting from the heat chamber 10 through the exit opening 31 passes into an adjacent cooling chamber 32. As shown in FIG. 2, the cooling chamber 32 is an enclosed space or conduit extending along the length of the bottom of the apparatus up along the right side with an opening 50 in a cooling chamber end wall 51 through which the film 22 is to be wound on a take up reel 52 after passing around an idler roller 53 which is mounted on a cabinet portion 54 of the apparatus.
Film 22 is supported in a predetermined path through the cooling chamber 32 by passing around the roller 30h adjacent the exit opening 31 from the heating chamber. From the roller 30h the film passes around rollers 55a, b and c and then out through chamber opening 50.
The film passing through the cooling chamber 32 is cooled by outside air flowing into the chamber through louvered openings as indicated at 56 and 57 in walls of the cooling chamber by the negative pressure applied at an exhaust port 58 which is in the cooling chamber adjacent the exit opening 31 from the heat chamber and which causes the cool air drawn into the cooling chamber to move in the reverse direction to the movement of the film 22.
The take up reel 52 is suitably mounted on the cabinet portion 54 and is driven through suitable connections to a take up motor 59. The motor 59 is a torque motor, the torque of which is controlled by conventional control circuitry. This motor maintains the film 22 under substantially uniform tension. A feeler arm 60 resting on the film accumulated on the take up reel 52 provides a signal to the control circuit of the motor 59 to assure constant film tension. The film speed is regulated by the rotational speed of the supply reel motor 27. The feeler arm 28 resting on film on the supply reel 23 and the feeler arm 60 resting on film as the take up reel 52 are each operatively connected to, or have incorporated therein, potentiometers which supply corrective signals to the respective motor control circuits for adjusting the rotational speeds of the respective motors to assure a constant film speed and uniform tension. A limit switch associated with feeler arm 28 is arranged and connected to shut off the supply motor reel, and thus stop the film transport when the supply reel 23 is almost empty.
Between the opening 50 in the downstream end of the cooling chamber and the roller 53 on the cabinet portion 54 is a clamping device 61 which straddles the path of film 22 to the take up reel 52 for clamping the film so as to provide a trailer strip of film that may be left threaded through the apparatus to become the leader for a new roll of film to be processed. When the film 22 is thus clamped the film is cut at the take up reel for removal of the take up reel of processing film.
In practice, a leader-trailer film strip is normally left threaded through the heating chamber 10 and cooling chamber 32 with its ends clamped respectively at the clamping devices 29 and 61 when the apparatus is not in use. Then for operation of the apparatus, a supply reel 23 of film 22 to be processed is mounted on the spindle 24, the lead end of the film is drawn around the roller 25 to the clamping, cutting and splicing device 29 and there spliced to the end of the leader-trailer strip. The other end of the leader-trailer strip which is clamped in the device 61 and extends to the take up reel location, is attached to a take up reel 52. For starting the processing the exhaust fan 48 is first turned on, then the heating unit 41 is turned on, and both are allowed to run for a short time before starting the motors 27 and 59 so as to allow the heating chamber to preheat to the required temperature before the movement of film 22 is started. After sufficient preheating, the transport system speed is set, the clamps 29 and 61 are released and the supply reel motor 27 and take up reel motor 59 are turned on, the control feelers 28 and 60 having been positioned against the portions of film on the respective reels. As indicated above, the supply rolls of film 22 to be processed are preferrably supplied with a leader-trailer strip at their end which will be the last through the apparatus to be cut off and clamped at the clamping device 60 when the tail end of the film reaches the latter device, so as to leave a leader-trailer strip threaded back to the apparatus to the clamping, cutting and splicing device 29 in readiness for processing the next reel of film. When the film transport motors 27 and 59 are shut off either by pushbotton on the front panel or by operation of the limit switch associated with the feeler arm 28, the heating unit 41 is turned off, but the exhaust fan 48 is left on long enough to be sure that all noxious gases are removed from the heating chamber.
The present invention relates to apparatus for processing photographic film of the type in which a latent image previously formed in a photosensitive coating on the film is developed and fixed by heat. In particular the invention is relatively compact apparatus for rapidly and effectively heat processing long strips or ribbons of such film.
In general, the subject film is developed and fixed by heating it to a particular temperature for a specified time and then cooling it. The problems involved in thus processing it are that when heated, the photosensitive coating, which is on one side of the film, is soft and easily scratched or marred so that the coated side must be kept out of contact with other surfaces, and the heating must be uniform or else the image density will vary. Also, as the photosensitive material develops and is fixed by heat, it gives off gases which must be removed quickly from the vicinity of the coating so as not to fog the developing images.
In known prototype apparatus for heat processing long lengths of film of the subject type, the film from a supply reel is drawn in a straight line through an elongated heat chamber out through a cooling chamber or through a span of open air to a take up reel. A principal problem with this known heat processing apparatus is that the effluent gases from the heated film tend to circulate back in contact with the film and cause fogging. Also, eddy currents produced in the stream of hot air traveling through the heating chamber cause variations in the temperature rise of the film at different areas of the film which result in variations in the image density.
BRIEF DESCRIPTION OF THE INVENTION
A principal object of the present invention is to provide apparatus for heat processing film of the subject type that assures even heating of the film and effective removal of the effluent gases so that the problems of variations in image density and fogging of the film are avoided, and to provide such apparatus which is more compact so as to be accommodated in less horizontal and/or vertical space than previous apparatus for the same purpose.
In accordance with the invention the heat chamber is an annular chamber separated from a compartment in the center of the annulus. Film from a supply reel mounted in the center compartment is fed into the heat chamber through which it moves along a spiral path, defined by support rollers, to an exit into a cooling chamber and through the cooling chamber to a take up reel. The spiral path of the film through the heating chamber is such that only the uncoated non-sensitive side of the film comes in contact with support rollers which define the path.
Heat for processing the film in the heat chamber is applied by jets of hot air from a plurality of nozzles spaced along the spiral path of the film and arranged so that the jets of hot air impinge on the photosensitive coating of the film at an acute angle so that the hot air sweeps or scrubs the film, sweeping the effluent gases away from the coated surface and out between adjacent nozzles into an exhaust stream of gases which flows back of the nozzles to an exhaust port. The hot air jets thus serve the dual functions of applying heat uniformly to the film and of immediately carrying the effluent gases away from the film.
The exhaust port for drawing effluent gases from the heat chamber, and an exhaust port in the cooling chamber, for drawing cool outside air therethrough, are adjacent to the film exit from the heat chamber to the cooling chamber and cooperate to prevent air from one chamber from contaminating the air in the other.
In addition to the advantages of the apparatus of this invention indicated above, the structure is such that the apparatus can be built for processing film of varying size, from 35mm to 91/2 inch wide film, without having to substitute parts.
Further objects, advantages and features of the apparatus of this invention will be apparent from the following more detailed description of an illustrative embodiment shown in the accompanying drawings, in which:
FIG. 1 is a front elevational view of film heat processing apparatus of this invention;
FIG. 2 is an enlarged front view partly in section of the apparatus of FIG. 1;
FIG. 3 is a section along the line 3--3 of FIG. 2;
FIG. 4 is a rear elevational view of the apparatus shown in FIG. 1;
FIG. 5 is a section along the line 5--5 of FIG. 3; and
FIG. 6 is an enlarged end view of an adjacent pair of the nozzles in the heat chamber, showing the jets of air flowing out from the nozzles.
Referring to FIGS. 1 and 2 of the drawings, the film heat processing apparatus of this invention includes an annular heating chamber 10 having inner side walls 11 and 12 and inner top and bottom walls 13 and 14 defining a central compartment 15 and outer side walls 16 and 17 and outer top and bottom walls 18 and 19. The front of the chamber 10 is closed by a pair of doors 20 which are each shaped like a U on its side so as to leave the central compartment 15 open to the front and rear when the doors are closed. The doors open to expose the interior of the heat chamber 10 for cleaning and for initially threading a film therethrough; it also provides access to the film in the chamber, to repair a break in the film, for example. The back of the heat chamber 10 is closed by a back wall 21 (FIGS. 3 and 4).
A supply of heat processable film 22 is provided on a supply reel 23 supported on a spindle 24 in the compartment 15. From the supply reel 23 the film feeds over an idler roller 25 and thence into the heat chamber 10 through an entrance opening 26 through the chamber side wall 11. The spindle 24 is driven by conventional drive connections to a variable speed motor 27. The speed of the motor 27 and thus the rotation of the supply reel 23 is adjusted over a predetermined range of speeds by means of conventional speed control mechanism. A feeler arm 28 resting on the roll of film 22 on the reel 23 measures the amount of film on the reel and provides a signal to the motor speed control mechanism to assure constant film speed. A conventional limit switch (not shown) is provided to shut off the apparatus (i.e., motors 27 and 53) when the film supply reel 23 is nearly empty.
Also in the compartment 15 is a conventional film clamping, cutting and splicing unit 29, which straddles the run of film 22 between the idler roller 25 and the entrance opening 26 to the heating chamber to be used for attaching the lead end of a supply of film 22 to a leader film strip (not shown) which is threaded through the apparatus and attached to a take up reel for leading film 22 through the apparatus at the start of a processing operation.
Film 22 entering the heat chamber 10 from the entrance opening 26 moves along successive convolutions of a spiral path formed by idler rollers 30a, b, c and d, which define the innermost convolution of the spiral, and idler rollers 30e, f, g and h, which define the outermost convolution. Between the idler rollers 30g and 30h the film passes out of the heat chamber through an exit opening 31 into a cooling chamber 32 in which the idler roller 30h is mounted. As shown, the film 22 passes around the successive rollers 30a to 30h so that only the inward side of the film 22 comes in contact with the roller surfaces. Thus the outward side of the film 22, which will be the sensitive side, does not come in contact with any surface while the film 22 is in the heating chamber 10.
Heat is applied to photographic material on the outward side of film 22 moving through the heating chamber 10 by means of nozzles 34 which are mounted at spaced intervals along the path of a film 22 through the heating chamber to be adjacent the outward sensitive side of film moving along the path. As best seen in FIGS. 3 and 5, the nozzles 34 are elongated, hollow tubular elements mounted on the back wall 21 of the heating chamber to extend across the width of photosensitive material 35 on a film 22 moving along the aforesaid path. The interior of each nozzle 34 opens through the wall 21 into a plenum chamber 36 which is back of the heating chamber 10, and which supplies hot air under pressure to the nozzles. The other ends of the nozzle elements 34 are closed and a plurality of holes or other openings 37 through the sides of the nozzles direct jets 38 of the hot air under pressure, out of the nozzles to impinge on a film 22 on the path through the chamber.
Referring to FIGS. 3 and 4, hot air under pressure is supplied to the plenum chamber 36 by a motor driven fan 40 and a heating unit 41 mounted in an inlet conduit 42 which opens into the plenum chamber 36 at one end and to the outside air at the other. The fan 40 draws outside air into the conduit 42 and blows it through the heating unit 41 into the plenum chamber 36.
As best in FIGS. 2, 5 and 6, the holes 37 in the nozzles 34 are arranged so that the jets 38 of hot air impinge on the photosensitive coating 35 of film 22 at an acute angle. The air forming the jets 38 diverges as it emerges from the holes 37 so that the jets are conical in shape, and the holes 37 are spaced so that the cones overlap prior to reaching the area of impingement. The hot air jets 38 of each nozzle 34 thus provide a lateral band of hot air impinging on the photosensitive coating 35 in a continuous band across the width of the layer of photosensitive coating.
As illustrated in FIGS. 2 and 6, the nozzles 34 are spaced apart and arranged along the path of a film 22 so that the hot air jets 38 impinge on the photosensitive coating 35 on the film at an acute angle and, from the direction in which the film is moving so that the direction of impingement of the jets 38 on the film is opposite the direction of film movement, thereby producing a good scrubbing action. The jets 38 of hot air thus sweep and scrub the photosensitive coating 35 on the film, and then deflect and circulate outward between adjacent nozzles and into exhaust streams of the hot air and effluent gases from the heated photosensitive film coating. These exhaust streams, as indicated by arrows 44 and 45, flow back of the outward sides of the nozzles 34. These exhaust streams flow along flow paths provided by the spacing of the nozzles 34 from the adjacent path of the film and from the outer walls 16, 17, 18 and 19 of the heating chamber; the exhaust flow is initiated and maintained by a combination of the positive pressure provided by the hot air jets 38 as deflected by the film 22 and a negative pressure applied at an exhaust port 46 which opens across a major portion of the annular width of the chamber 10 through a portion of the back wall 21 adjacent the film exit opening 31. The hot air jets 38 thus not only heat the photosensitive coating 35 on film 22 but also carry off the effluent gases generated by the heat developing and fixing process into exhaust streams that carry the effluent gases from the chamber in a manner which prevents the effluent gases from coming in contact with the photosensitive coating.
Referring to FIG. 3, an exhaust conduit 47 is provided at the back of the apparatus and the exhaust port 46 of the heat chamber 10 (as well as an exhaust port 58 from a cooling chamber 32, subsequently described) opens into the exhaust conduit 47. The other end of the exhaust conduit 47 opens to the air, suitably outside the building in which the apparatus is located and negative pressure is created at the exhaust port 46, and at cooling chamber exhaust port, for assisting the exhausting of the effluent gases by suitable means such as a motor driven exhaust fan indicated at 48 in the exhaust conduit 47. It will usually be desirable to filter the exhaust gases as they leave the apparatus by suitable means, such as a charcoal filter 49 shown in the conduit 47, to remove any noxious materials from the exhaust gas.
As previously mentioned, film 22 exiting from the heat chamber 10 through the exit opening 31 passes into an adjacent cooling chamber 32. As shown in FIG. 2, the cooling chamber 32 is an enclosed space or conduit extending along the length of the bottom of the apparatus up along the right side with an opening 50 in a cooling chamber end wall 51 through which the film 22 is to be wound on a take up reel 52 after passing around an idler roller 53 which is mounted on a cabinet portion 54 of the apparatus.
Film 22 is supported in a predetermined path through the cooling chamber 32 by passing around the roller 30h adjacent the exit opening 31 from the heating chamber. From the roller 30h the film passes around rollers 55a, b and c and then out through chamber opening 50.
The film passing through the cooling chamber 32 is cooled by outside air flowing into the chamber through louvered openings as indicated at 56 and 57 in walls of the cooling chamber by the negative pressure applied at an exhaust port 58 which is in the cooling chamber adjacent the exit opening 31 from the heat chamber and which causes the cool air drawn into the cooling chamber to move in the reverse direction to the movement of the film 22.
The take up reel 52 is suitably mounted on the cabinet portion 54 and is driven through suitable connections to a take up motor 59. The motor 59 is a torque motor, the torque of which is controlled by conventional control circuitry. This motor maintains the film 22 under substantially uniform tension. A feeler arm 60 resting on the film accumulated on the take up reel 52 provides a signal to the control circuit of the motor 59 to assure constant film tension. The film speed is regulated by the rotational speed of the supply reel motor 27. The feeler arm 28 resting on film on the supply reel 23 and the feeler arm 60 resting on film as the take up reel 52 are each operatively connected to, or have incorporated therein, potentiometers which supply corrective signals to the respective motor control circuits for adjusting the rotational speeds of the respective motors to assure a constant film speed and uniform tension. A limit switch associated with feeler arm 28 is arranged and connected to shut off the supply motor reel, and thus stop the film transport when the supply reel 23 is almost empty.
Between the opening 50 in the downstream end of the cooling chamber and the roller 53 on the cabinet portion 54 is a clamping device 61 which straddles the path of film 22 to the take up reel 52 for clamping the film so as to provide a trailer strip of film that may be left threaded through the apparatus to become the leader for a new roll of film to be processed. When the film 22 is thus clamped the film is cut at the take up reel for removal of the take up reel of processing film.
In practice, a leader-trailer film strip is normally left threaded through the heating chamber 10 and cooling chamber 32 with its ends clamped respectively at the clamping devices 29 and 61 when the apparatus is not in use. Then for operation of the apparatus, a supply reel 23 of film 22 to be processed is mounted on the spindle 24, the lead end of the film is drawn around the roller 25 to the clamping, cutting and splicing device 29 and there spliced to the end of the leader-trailer strip. The other end of the leader-trailer strip which is clamped in the device 61 and extends to the take up reel location, is attached to a take up reel 52. For starting the processing the exhaust fan 48 is first turned on, then the heating unit 41 is turned on, and both are allowed to run for a short time before starting the motors 27 and 59 so as to allow the heating chamber to preheat to the required temperature before the movement of film 22 is started. After sufficient preheating, the transport system speed is set, the clamps 29 and 61 are released and the supply reel motor 27 and take up reel motor 59 are turned on, the control feelers 28 and 60 having been positioned against the portions of film on the respective reels. As indicated above, the supply rolls of film 22 to be processed are preferrably supplied with a leader-trailer strip at their end which will be the last through the apparatus to be cut off and clamped at the clamping device 60 when the tail end of the film reaches the latter device, so as to leave a leader-trailer strip threaded back to the apparatus to the clamping, cutting and splicing device 29 in readiness for processing the next reel of film. When the film transport motors 27 and 59 are shut off either by pushbotton on the front panel or by operation of the limit switch associated with the feeler arm 28, the heating unit 41 is turned off, but the exhaust fan 48 is left on long enough to be sure that all noxious gases are removed from the heating chamber.