Transport mechanism for a photographic film processor

Abstract

Apparatus for engaging and moving a film strip through a light-tight processor having tanks of processing chemicals, including a film clip which fastens to the front of the film and which has a rearwardly-facing opening, and a pickup member which enters the opening in the film clip to drag it and the film strip through the tanks of chemicals.

Description

BACKGROUND OF THE INVENTION

This invention relates to apparatus for processing film.

One diagnostic method which is increasingly employed in hospitals, utilizes a wide film strip to record a sequence of x-ray images during a medical procedure. Typically, 105 millimeter film is utilized which may not have sprocket holes along the edges, and the images extend to nearly the edges of the film. The exposed film is usually processed in a leaderless roll machine that is designed primarily for sheet film. Such processing can harm the film in that the rollers which must firmly grasp the film to move it through the machine, often produce small areas of damage to the film emulsion, which is especially detrimental where the images are small. The emulsion is highly susceptible to scratching when it is being developed, but becomes resistant to damage after development and drying. A processing machine which could move a film strip in an accurately controlled manner through tanks of processing chemicals with minimal damage to the film emulsion would permit the developing of film strips so they had very clear images even in a hospital environment.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the present invention, a film transport is provided which reliably moves a film strip through tanks of chemicals. The film transport includes a pickup bar that engages a clip attached to the front end of a film strip, to pull the film strip through the tanks of chemicals. The clip is securely fastened to the film strip by punching a pair of holes at the front end of the film strip and inserting the clip therein. The clip has a rearwardly facing opening which receives the pickup bar. The pickup bar is fixed to a pair of belts that move it positively through the film path.

The novel features of the invention are set forth with particularly in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a film processor constructed in accordance with the invention;

FIG. 2 is a simplified partial sectional view of the processor of FIG. 1, taken on the line 2--2 of FIG. 1 and showing the transport thereof;

FIG. 3 is a partial perspective view of the processor of FIG. 1, showing the manner in which a transport bar of the processor engages a film clip at the front end of a film strip that is to be processed;

FIG. 4 is a view taken on the line 4--4 of FIG. 3, but with the transport bar received in the film clip therof;

FIG. 5 is a partial perspective view of the transport of FIG. 2, showing how the film strip is guided along a tank thereof;

FIG. 5A is front elevation view of one of the rollers of FIG. 5;

FIG. 6 is a left rear perspective view of a portion of the transport of FIG. 2, showing the termination portion thereof;

FIG. 6A is a left side elevation view of part of the termination portion of FIG. 6;

FIG. 7 is a right rear perspective view of the termination portion of FIG. 6;

FIG. 8 is a view taken on the line 8--8 of FIG. 5;

FIG. 9 is a partial sectional and elevation view taken on the line 9--9 of FIG. 1, showing the replenishing system of the invention;

FIG. 9A is a partial sectional view of the replenishing system of FIG. 9, showing the plug in a raised position; and

FIG. 10 is a plan view of a roller assembly constructed in accordance with another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 and 2 illustrate a film processor 10 which includes a frame 12 that supports several tanks 14, 16, 18 and 20 which hold processing chemicals, the frame also supporting a dryer chamber 22. The machine has a film path 24 along which a strip of film can move, to bring the film down into each tank and up out of the tank and into the next one. The processor is designed so that a portion 10A of the processor forms a tank-holding system, while another portion 10B forms a transport that can be mounted in the tank-holding system, the tank-holding system 10A also being capable of holding other transports such as those for small sheets of film instead of strips. The film processor 10 is designed to receive a cartridge 26 containing exposed film to be developed, the cartridge being mounted at an input end 28 of the frame. The film can traverse the film path 24 until it is received on a wind-up roller 30 at an output end of the frame. The film strip is moved along the film path by a transport member or bar 32 which is fixed to two belts 34 which extend along the film path. The film strip moves around a set of rollers such as 36, while the belts 34 extend about sprocket wheels that are mounted coaxial with the rollers 36. One pair of sprocket wheels which lie coaxial with a brush roll 136, to be described below, is driven by a motor 38 to move the belts 34 and the transport bar 32 thereon along the film path.

When the leading end of a film strip, extending from the cartridge 26, is inserted into the processor, the film strip depresses a film sensor 40 which delivers a signal over a line 42 to a latching relay 44. The relay 44 then connects a power line 45 to the motor 38 to turn one pair of sprocket wheels and move the belts 34 along the film path. The transport bar 32 will engage a clip attached to the leading end of the film strip, as will be described below, and the bar will then move the strip along the film path towards the wind-up roller 30. The sensor 40 is also coupled to a timer 46, and when the trailing end of a film strip passes by the sensor, the sensor ceases to deliver a signal over line 42 and thereby begins a timing cycle of the timer 46. After a predetermined period sufficient for the trailing end of the film strip to pass completely through the processor, the timer delivers a signal to an off input 48 of the relay 44, to turn off the relay so that the motor 38 is no longer energized and the machine stops.

The particular processing machine 10, and especially the transport 10B thereof, is especially useful for processing 105 millimeter film that is often used in making a series of x-ray exposures in a short period of time, as in recording the path of a radiopaque dye injected into an artery of the human body. Such a diagnostic film strip or film, shown at 60 in FIG. 3, typically contains images such as 62 which extend across nearly the entire width of the film, and the film sometimes contains no sprocket holes or the like along either edge. In order to permit the transport bar 32 to move the film through the processing machine, a film clip 64 is provided which is securely attached to the leading end portion 66 of the film strip. The film clip 64 includes a pair of film-holding parts 68 which extend through holes 70, 72 in the film, and a pair of bar-receiving parts 74 which are designed to attach to the transport bar 32. Each bar-receiving part 74 has a rearward opening 76 through which the transport bar 32 can pass to be captured in the bar-receiving parts 74 of the clip.

In order to prepare a film strip for processing, a technician punches the pair of laterally-spaced holes 70, 72, in the leading end portion 66 of the film, as with a simple paper-type punch with punch members spaced apart by the required distance. He then slips the film-holding parts 68 through the holes and slides them up against the forward edges of the walls of the holes, to hold the film clip firmly to the film strip. The technician then inserts the leading edge portion 66 of the film with the clip thereon into the processor along an entrance path therein, so that the clip lies at a pick-up location in the path of the transport bar 32. The housing 77 of the processor is substantially light-tight along most of the film path, and the cartridge 26 seals the entrance to the processor, so that as film is drawn out of the cartridge the film is protected from light. As the film or clip trips the sensor 40, the motor 38 is energized to begin movement of the transport bar 32 along the film path. As the transport bar passes by the film clip, the bar enters the rearward opening 76 to firmly engage the film clip and drag the film strip out of the cartridge, into the processor, and along the film path 24.

The belt appartus 34 which moves the transport bar 32, includes a pair of narrow belts 80, 82 with sprocket holes 84 therein, the belts being attached by rivets 86 to the transport bar. The belts 80, 82 are laterally spaced by a distance B which is greater than the width of the widest film strip 60 designed to be processed in the machine. The film moves along a series of major rollers such as 36a, 36b, shown in FIG. 5 and along minor or guide rollers 90, 92. A pair of sprocket wheels 94, 96 (FIG. 5a) is rotatably mounted on each side of each major roller to engage corresponding belts 80, 82. Each sprocket wheel has sprockets 98 that are received in the holes 84 of the belts to prevent slippage of the belts and therefore assure that the transport bar 32 will extend perpendicular to the film path. The rollers such as 36a which lie between the sprocket wheels 94, 96 are designed to support and guide the film strip in its movement through the processor. The guide rolls 90, 92 guide both the belts and film strip along the film path.

Most of the rolls which come in contact with the emulsion side of the film strip are designed to support the film without damaging the emulsion, particularly at the middle portion of the strip where images such as 62 are positioned. Each roller such as roller 36a shown in FIG. 5A includes a pair of short cylindrical support surfaces 102, 104 extending inwardly a short distance d from a corresponding sprocket wheel, and with a wide cutaway or concave portion 106 between the support cylinders 102, 104. The cutaway portion 106 has a diameter smaller than that of the support cylinders 102, 104 so that it does not contact the diagnostic film 60 and therefore cannot damage the emulsion thereon. The width C of the cutaway portion 106 is less than the width Y of the diagnostic film, so that the edge portions of the diagnostic film 60 are supported on the cylinders 102, 104. Thus, the film is driven along the film path without slippage, while being closely guided in movement therealong, with minimal damage to the emulsion of the film. The guide rollers 92 (FIG. 8) which are on the emulsion side of the film, also have cutaway portions 108 between cylindrical support portions 110, 112, to provide good support for the film. The guide rollers 94 on the non-emulsion side of the film do not have to be provided with cutaway portions.

Where a processor will always be used with film of a predetermined width, rollers with simple cutaways of the type shown in FIG. 8 can be utilized. However, where a processor may be occasionally utilized to develop film strips of a variety of smaller widths, a roller apparatus of the type illustrated in FIG. 10 may be utilized, wherein at least the roller 114 which contacts the emulsion side of the film has a tapered cutaway portion 116 instead of a cylindrical cutaway portion. The tapered cutaway portion 116 tends to engage the edge portions of those films that are not wide enough to rest on the cylindrical end surfaces 118 of the roller, so that there is minimal contact of the roller with the center portion of the film emulsion.

As a film is pulled through the processor, it is desirable to apply firm pressure along the rearward part of the film strip so that it will be held down at curves of the path. Accordingly, a hold-down roll assembly 120 (FIG. 2) is provided at each of the rollers which must contact film coming out of the tank and direct it down into the next tank. The hold-down roll assembly 120 includes a pair of rollers 122 rotatably mounted on a frame 124, which is, in turn, pivotally mounted on a bracket 126 on the frame 12 of the machine. One of the roll assemblies 120' which is positioned between the first and second tanks 14, 16 is useful in serving as a squeegee that tends to squeeze off developer from the film. Its opposed major roll 36c is not cut-away, in order to provide a squeegee action.

After the film has passed through the four chemical-holding tanks and the dryer 22, so that its emulsion has become hardened, it passes into a termination assembly 130 which includes a lamp 132 and translucent plate 134 that permit viewing of the developed film as it emerges from the dryer. The leading end of the film, with the clip and transport bar thereon, then passes onto a brush roll 136 which disengages the film clip from the transport bar 32 so that the film clip and the leading end of the film attached thereto can fall along the path portion 138 onto the wind-up roll 30.

FIGS. 6, 6A and 7 illustrate details of the termination assembly 130 where the film clip is detached from the transport bar. The termination apparatus includes a pair of sprocket wheels 94d, 96d which are normally driven by the motor 38 of the processor to advance the belts 84, 86 along the film path. When the transport bar 32, with the film clip and leading end of the film strip, reaches the brush roll 136, the sprocket wheels 94d, 96d are automatically disengaged from the motor so that the belts and transport bar remain stationary with the leading end of the film partially wrapped about the brush roll 136. However, even though the belts and transport bar are stationary, the brush roll 136 turns. As the brush roll turns, it tends to advance the film clip and film. When the film clip 64 advances a small distance without the transport bar 32, as shown in FIG. 6A, the transport bar 32 is withdrawn through the rearward opening 76 of the film clip and therefore the film clip and transport bar become disengaged. The front portion of the film strip 60 is then free to fall down onto the windup roll 30. The film clip 64 is constructed of ferromagnetic material, while the windup roll 30 is constructed with magnets, so that when the clip 64 falls onto the roll 30, it tends to remain engaged with the roll. The roll 30 then turns and winds up the film strip thereon. A thin cardboard tube 144 is normally placed around the roll 30, so that after the film is wound thereon the cardboard tube can be removed together with the film. Thus, the transport bar and film clip permit automatic positive engagement with the film at the beginning of processing, and automatic disengagement at the end of processing, to facilitate the processing of the film strip. It may be noted that the brush roll 136 is in an exposed area, and therefore if disengagement should not occur, a technician can easily disengage the transport bar and film clip by hand.

As shown in FIG. 7, a first gear 131 has a pin 133 that is in the path of the transport bar. When the transport bar engages the pin 133, the gear 131 turns, to turn a gear 135 which is fixed to a cam 137. The cam then moves an arm 139a on a bracket 139 which is pivotally mounted about an axis 141. This causes a constantly rotating gear 143 on the bracket to disengage from a gear 145 which is fixed to the same shaft as the pair of ratchet wheels 94d, 96d that drive the belts 84, 86. Thus, the belts and the transport bar stop moving. The brush roll 136 is driven from a separate drive chain 147 which rotates the brush roll whenever the machine is on. Some of the major rolls 36 are also driven whenever the machine is on, while the other rolls 36 are free wheeling, so that the entire film strip can be pulled out of the machine.

As a film moves through the tanks of chemicals, the chemicals tend to become depleted, or in another word, their potency decreases. FIGS. 9 and 9A illustrate the replenishing system which replenishes the chemicals in tank 14 each time a predetermined length of film has passed through the tank. The replenishing system includes a tubular drain outlet 150 at the bottom of the tank from which chemicals can be drained into a basin 152 for later disposal, and a pipe-like plug 154 which normally plugs the outlet. The plug 154 has an overflow hole 156 which can receive fluid 158 in the tank to drain it. The replenishing system also includes a device 160 for moving a controlled amount of the fluid 158 from the tank into the drain, and apparatus 162 for flowing fresh chemical into the tank to replace the amount moved into the drain so that fluid in the tank is restored to its original level. The device 160 for moving fluid from the tank to the drain includes a plunger 164 which can be moved down into the tank to the position 164A by a motor 166 to displace some of the fluid in the tank and therefore raise the level of the fluid. This causes some of the fluid 158 to overflow through the overflow hole 156 in the plug and down into the drain outlet 150. A short time later, the motor moves the plunger 164 upwardly out of the tank and back to its original position. This causes the fluid 158 to move down to a level indicated at 168.

The replenishing apparatus 162 includes a holder 170 which holds a container 172 of replenishing chemical which has an outlet extension 174 thereon. The container holder 170 supports the container so that an open lower end 176 of the container with the extension 174 thereon lies at the desired level of fluid in the tank. When the fluid level drops below the desired level, as to the lower level indicated at 168, fluid in the container 172 can flow out of the container while air bubbles flow into the container. However, when the fluid level reaches a height equal to the bottom 176 of the container-extension combination, air cannot bubble into the container any longer and the fluid is prevented from flowing out of the container. Thus, the fluid level in the tank is restored to its original level solely by the introduction of the replenishing chemicals from the replenishing container 172. The volume of replenishing chemical introduced into the tank is equal to the additional volume of the piston 164 which is introduced into the tank, less the volume required to raise the fluid level a small amount to begin an overflow into the overflow hole 156.

The plunger 164 is guided in up and down movement by guides (not shown), and the plunger has a rack 178 extending along its center which is engaged by a pinion 180 coupled by a drive chain 182 to the motor 166. The motor 166 is energized by a counter 184 after a predetermined number of developing cycles, the counter 184 being coupled to the sensor 40. The counter operates a circuit 186 which first energizes the motor 166 to rotate in one direction to move the plunger 164 down, and which then energizes the motor in an opposite direction to raise the plunger. A similar replenishing apparatus is provided for each of the other three chemical-holding tanks 16, 18, 20, so that the chemicals in all four tanks are replenished at intervals.

The plug 154 is designed to facilitate the complete draining of the tank 14. The plug includes a lower end with a guide portion 190 slidably received in the drain outlet 150 and movable between the downward position shown in FIG. 9 and the upward position shown in FIG. 9A. An O-ring 192 at the lower portion of the plug normally forms a fluid tight seal with the drain outlet 150 to plug it. However, when the plug is pulled up as shown in FIG. 9A, the O-ring 192 is pulled out of the drain opening so that fluid can flow therethrough. In order to permit rapid fluid flow, the plug is provided with several holes 194 through which fluid can pass. Most of the area of the holes 194 lies above the bottom of the tank when the plug is in its upward position. However, even in its upward position, the extreme lower end of the plug still lies within the drain opening 150, so that reinsertion of the plug is easily accomplished. The upper end of the plug includes a pin 196 which will hit an upper wall 198 of the processor frame when the plug is pulled up, to limit upward movement of the plug so that the extreme lower end of the plug does not move out of the drain opening 150. The upper end of the plug extends through a hole 200 in the frame, and a handle 202 is attached to the upper end of the plug to facilitate raising of the plug. A technician can grasp the handle 202 so that it pivots to the vertical, as indicated at 202A, to pull up on the plug and drain the tank. He can then reinsert the plug by merely pushing down on the top of the plug until a flange 204 at the bottom of the plug abuts the bottom of the tank.

The replenishing container 172 which contains a replenishing chemical, should be provided with opaque walls to prevent the entrance of light into the processor. However, opaque walls would prevent an operator from readily determining when to replace the replenishing container by noting the level of fluid. To enable such an indication, the container 172 is provided with a light transmitting strip 206 (FIG. 1) through which fluid in the tank can be observed. The strip 206 is formed by merely masking the strip area when coating the tank with an opaque paint. The strip 206 is narrow enough and the light path from the strip to the paint area where film is developed is convoluted enough, so that only an insignificant amount of light will reach the film.

The processing machine 10 contains numerous electrical circuits that assure close control of the processing cycle. One of the problems that often arises in the use of film processors is that the chemicals develop fumes that can result in chemical deposits and corrosion. The electrical circuits are particularly sensitive to such deposits and corrosion. In order to minimize such damage to the electrical circuits, most of them are contained in a separate compartment illustrated at 210 in FIG. 1. A blower 212 is provided which has an inlet 214 open to the environment and an outlet 216 opening into the electrical compartment 210. The blower is kept on throughout the day, even when the machine is on a stand-by basis, to keep the electrical compartment 210 pressurized. That is, air in the compartment 210 is at a slightly higher pressure than the pressure of the atmosphere. This prevents the entrance of fumes from the adjacent region where the tanks of chemicals are kept, to thereby minimize chemical deposits and corrosion resulting from chemical fumes seeping into the electrical compartment.

A technician can process diagnostic film which is contained in the cartridge 26 by punching a pair of holes in the leading end of the film, attaching the film clip 64 to the film strip, and inserting the leading end of the film strip with the clip thereon into the processor. Then he depresses a start button 218 (FIG. 1) which causes energization of the machine to begin moving the belts and transport bar 32 thereof along the film path. As soon as the transport bar reaches the film clip, it enters the clip and thereafter drags the clip and the film attached thereto along the film path. After a few minutes, the processed film passes by a viewing station in front of a lamp 132, where the film can be viewed. The film is wound onto a cardboard roll on the windup roll 30, and after a short time the machine automatically stops. The wound up film then can be removed for detailed study. The entire processing procedure can be performed in an ordinary lighted room.

Thus, the invention provides a film processor which moves a film strip in a closely controlled and protected manner and which maintains the processing chemicals at a closely controlled potency, utilizing a simple reliable mechanism that requires minimal skill in operation and maintenance. Movement of the film is facilitated by the use of a film clip attached to the film and a transport for reliably moving the film clip, and by the use of rollers that minimize contact with the film strip. Replenishment of the chemicals is accomplished by a replenishing system that utilizes a simple plunger for draining off some of the fluid and a simple "chicken feeder" apparatus for restoring the drained off fluid with replenishing chemicals.

Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art and consequently it is intended that the claims be interpreted to cover such modifications and equivalents.

Claims

1. A film processor system for processing a film strip comprising:

a film clip designed to be fastened to the front end of a film strip, said clip having a rearwardly-facing opening;

a light-tight processor frame;

a plurality of tanks disposed on said frame for holding processing chemicals;

a clip-engaging member formed to fit into said opening of said clip to engage and pull it; and

moving means including belt means extending into and out of said tanks, for moving said clip-engaging member along a predetermined path which includes a portion that extends into and out of said tanks, to drag the film strip through said tanks;

said frame being constructed to hold a film with a film clip fastened thereto, so the clip lies in the path of said clip-engaging member at a portion of the frame which is light-tight, and with the opening of the clip facing rearwardly with respect to said path so that the clip-engaging member enters said opening as it moves along said path, to pick up said clip and drag it and the film fastened thereto along said path portion.

2. The system described in claim 1 including:

a film strip having a forward end portion with a pair of laterally-spaced holes therein; and wherein

said film clip includes a clip member with a pair of film-engaging parts, each part forming a loop with one side extending through a hole in said film strip and said loop extending closely around the forward edge of the wall of the hole.

3. The system described in claim 1 wherein:

said processor frame forms a substantially light-tight housing along most of said film path, and includes an opening for receiving said film strip; and including

a cartridge holding a film strip, said cartridge attached to said processor over said opening therein, and with the front end of said film strip extending into said opening in said housing and extending parallel to said belt means, said film clip attached to the front of said film strip and lying in the path of said clip-engaging member.

4. A film processor system for processing a film strip comprising:

a clip having a pair of spaced film-holding parts which can engage a film, and a bar connecting said film-holding parts, each film-holding part including a bent-over portion that can fit closely around a film and another portion that can receive a clip-engaging member;

a light-tight processor frame;

a plurality of tanks disposed on said frame for holding processing chemicals;

a clip-engaging member formed to engage said clip and pull it; and pg,21

moving means including belt means extending into and out of said tanks, for moving said clip-engaging member along a predetermined path which includes a portion that extends into and out of said tanks, to drag the film strip through said tanks;

said frame being constructed to hold a film with a film clip fastened thereto, so the clip lies in the path of said clip-engaging member at a portion of the frame which is light-tight, to pick up said clip and drag it and the film fastened thereto along said path portion.