US 3787689 A
Apparatus for automatically replenishing developer and fixer solution in an automatic photographic film processor in response to accumulated exposure density of processed film. The exposure of the continuously moving film is electronically scanned at the dryer exit. The scanner, whose timing cycle is responsive to the film speed, controls the transmission of exposure signals from the scanner photocell to an integrator. The exposure density accumulated by the integrator is applied to a threshold detector which controls a developer-replenisher-pump timer and a fixer-replenisher-pump timer. Developer and fixer replenisher bypasses are provided as well as a double replenisher option.
Description (OCR text may contain errors)
O United States Patent 1 91 1111 3,787,689
Fidelman Jan. 22, 1974  EXPOSURE SCANNER AND REPLENISHER 3,345,908 10/1967 Jensen 250/219 FR CONTROL 3,066,225 11/1962 Uphof 250/219 FR  Inventor: David Fidelman, Roslyn Heights, Primary Examinr james Lawrence Assistant ExaminerD. C. Nelms I  A i Henry H X-R Products, Inc" Attorney, Agent, or Firm-Fidelman, Wolffe, Leitner Huntington Valley, Pa. & y
 Filed: May 16, 1972 ABSTRACT  Appl. No.: 253,789 Apparatus for automatically replenishing developer and fixer solution in an automatic photographic film processor in response to accumulated exposure den- 25? sity of processed film. The exposure of the continu- WE ously moving film is electronically scanned at the DP 95/89 96 d dryer exit. The scanner, whose timing cycle is responsive to the film speed, controls the transmission of exposure signals from the scanner photocell to an inte-  References cued grator. The exposure density accumulated by the inte- UNITED STATES PATENTS grator is applied to a threshold detector which con- 3,554,109 l/197l Street 95/89 R trols a developer-replenisher-pump timer and a fixer- 315611344 2/ 1971 g 95/89 R replenisher-pump timer. Developer and fixer replen- 'z a' g isher bypasses are provided as well as a double repleno aya 3,696,728 10/1971 Hope 95/89 R Sher opuon' 3,699,349 10/1972 Paulus 250/219 FR 13 Claims, 5 Drawing Figures F/AM INTEGRA TOR flakes/low zj f A c m i K rtrag. 7 --a- ZZEV- PUMP .30 l mm? PUMP A m l T/Mfl? 71267? PUMP Z0 5 0 T/MR 60 F7! M 5W- F5 1 EXPOSURE SCANNER AND REPLENISHER CONTROL BACKGROUND OF THE INVENTION The present invention relates generally to automatic electronic photo-processing and more specifically to an automatic electronic film exposure scanner and chemical replenisher control apparatus.
DESCRIPTION OF THE PRIOR ART In the field of automatic photographic film processors, a need has developed for a means of accurately replenishing developer and fixer solutions. Previously, the process of replenishing the baths has been performed by the machine operator based on his prior experience and knowledge. Also, tests have been performed on sample film strips to indicate when the baths need replenishing. Not only is the manual process of replenishing and testing for replenishment timeconsuming, but its accuracy and success depends on the experience and knowledge of the operator.
Those concerned with replenishment requirements of automatic photoprocessing equipment have been developing automatic replenishers. One of the most critical problems is the development of an electronic scanner which is electronically simple and accurate.
SUMMARY OF THE INVENTION The present invention is an exposure scanner and replenisher control which measures the density of the film and controls the replenisher pumps to add developer and fixer in proportion to the rate of depletion. A
light source and photocell assembly scans the entire width of the film and provides an electrical signal proportional to the density of the exposure. An integrator which accumulates or integrates the photocell signal provides a voltage output proportional to the cumulative amount of exposure of the film that passes over the photocells. A threshold sensing circuit determines when the cumulative film exposure has reached a preset level, at which point an output signal is provided to start the pump motor timers. A scanner timer which is initiated by a switch, whose rate of activation is determined by the rate at which the film moves, controls the scanning period. Each time the switch is activated, the photocell signal is measured for said pre-set scanning period. The timer setting and rate of switch activation are selected so that the entire surface of the film is scanned when the film is moving at maximum transport speed. The developer and fixer pump motors each have their own variable timers.
The present invention includes developer replenisher and fixer replenisher bypass switches which when activated permit replenishment of the appropriate solution even though the pump motor timers are not activated. Other features are a drift lockout control which disconnects the photocell and the integrator when film is not being processed so as to limit the amount of accumulation of error voltages.
OBJECTS OF THE INVENTION rately measures the rate of depletion and quickly and automatically corrects the amount of developer and fixer solution required.
Other objects, advantages, and novel features of the present invention will become apparent from the following detailed description when considered in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic drawing of an automatic film processor which is to be controlled by the present invention;
FIG. 2 is a block diagram of the present invention;
FIG. 3 is a detailed schematic of the block diagram of FIG. 2;
FIG. 4 is an electrical schematic showing controls outside the exposure scanner;
FIG. 5 is an electrical schematic of a timer used in FIGS. 2 and 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT The exposure scanner and replenisher control of the present invention is found most useful in the automatic photographic film processor depicted in FIG. I. The film is introduced on a feed table into the first developing bath. At the entrance of the bath is an air switch film sensor which senses the leading and trailing edge of the exposed film strip to be processed. As the exposed film enters the processor, an air stream is broken which activates the automatic replenisher system and exposure scanner. The timer triggers a signal bell at a predetermined time after the trailing edge has been sensed by the air switch film sensor to indicate that a second sheet can be fed in. The film then enters a double rack tank where it is developed for 30 seconds to 6 minutes, depending on the machine speed, by a temperature controlled, filtered and agitated developer so lution. It then passes through a fixer solution for 15 seconds to 6 minutes and then is rinsed in a wash tank of tempered water. Excess solution is squeezed off before the film enters the dryer section. The heated air is forced through a set of nozzle plates for high velocity drying. As the dry sheets emerge from the dryer, it passes over a series of photocells which measure the silver concentration, density, of the film and triggers timed replenisher pumps to replace the consumed chemical solutions. As indicated in FIG. I, the developer and fixer are replenished from separate tanks and by separate timed pumps.
The automatic replenisher system is controlled by the exposure scanner depicted in block diagram in FIG. 2. The film passes between light source LS and photocell PC. The electronic signal from the photocell is passed to an integrator 10 made up of an operational amplifier with a capacitor feedback. The passage of the electronic signal from the photocell to the integrator is controlled by a scanner-timer 60. This scanner-timer operates switch Kl-2 to pass the electronic signals to the integrator 10. The scanner-timer 60 is activated for a fixed time interval at a rate dependent upon film speed. The film speed is detected by film switch ES.
The voltage output of the integrator 10 is proportional to the cumulative amount of exposure of the film that passes over photocell PC. This cumulative exposure is displayed on meter 20 and simultaneously passed to a threshold detector 30. The threshold detector or sensing circuit, upon detecting a given amount of the cumulative exposure density, activates developer pump-timer 40 and fixer pump-timer 50.
The exposure scanner and replenisher control, designated generally 100, is more specifically shown in the schematic of FIG. 3. It should be noted that everything to the right of the dotted line is considered to be within the single exposure scanner and replenisher control unit 100. Everything to the left of the dotted line is electrical circuitry external the exposure scanner 100, yet internal the total automatic developing and processing unit.
The film passes between a light source LS, generally a fluorescent lamp, and photocells PC 1-4. Each photocell is shunted by an adjustable resistor 12-13. The electrical signals from photocells PC l-PC4 are impressed across resistor 22. A movable arm moves across resistor 22 to adjust the photocell sensors sensitivity. Summed into the integrator along with the voltage from the photocell sensor are the voltages from two other voltage divider networks. The first voltage divider consists of resistor 24 and a slidable contact to adjust the double replenisher control to be explained later. The second voltage divider, across resistor 26, is to adjust the light balance. The voltage from the light balance divider 26 is balanced against the voltage from the photocells for unexposed film. When exposed film is between the light source and the photocells, the photocell output voltage is reduced by an amount proportional to the exposure. This reduction is the voltage which is integrated to obtain the cumulative film exposure.
The signal from the photocell is then passed through a combination of switch 51-8 and contact KI-2 of relay Kl on the output of the scanner-timer 60. Switch Sl-B is one of two ganged switch elements of switch S1. The other one is SI-A in the power source circuitry of the exposure scanner and replenisher control circuit. The position on both contacts for switch SI are the operative, test, and off positions. Depending upon selection of the proper position for switch 81-8 and the operation of switch contact KI-Z, the electrical signal is passed through contact KS-l to the integrator 10. Contacts KS-l are closed in response to relay K-S in the drift control circuitry. K-S is activated by the closing of contacts R-I from the drift control relay external from the exposure scanner in replenisher control unit.
The integrator is an amplifier with capacitative feedbacks 32 and 34. Sjunted across capacitor 34 is a normally closed switch S-3. Switch 8-3 is depressed to expand the reading scale of meter by a factor of 10. By depressing this switch, the capacitance in the integrative feedback of the operational amplifier is reduced. The balance of the operational amplifier is maintained by the adjustment of resistor 28. In shunt across the capacitative feedback of the operational amplifier is a manual reset switch, S2-A. In parallel across the manual reset switch is a resistor 36 in series with contacts K2-I which is activated by the reset relay K-Z. The signal from the photocells are integrated in integrator l0 and an output voltage proportional to the cumulative amount of exposure of the film that passes through the photocells.
As well as being displayed by meter 20, the cumulative exposure is applied to threshold detector through a voltage divider containing resistor 38. An adjustable arm across resistor 38, known as master replenisher control, determines the level at which the threshold detector will be activated. The threshold detector, which may be a Schmitt trigger. determines when the cumulative film exposure or density has reached a preset level set by master replenisher control arm across resistor 38. At that point, an output signal is provided to start fixer pump-timer and developer pump-timer 40. Also an output signal is provided to transistor switch 0-1 to initiate automatic reset relay K-Z. A second manual reset switch 82-13, which is ganged with manual reset contact S2-A in the integrator circuitry, is in series with reset relay K-2. Also in series with this normally closed S2-B switch are contacts Kl-ll which are closed by relay KI on the output of scanner-timer 60.
Upon the activation of developer pump-timer 40 and fixer pump-timer 50, relays K-3 and K4 are activated which close contacts K3-ll and K441 to connect the AC power to developer replenisher pump and fixer replenisher pump, respectively. Both timers period may be adjusted by adjustable resistors 42 and 52, respectively. Upon activation of the developer replenisher pump and the fixer replenisher pump, indicator lamps l-l and I-2 are ignited. Normally open switch S4 and normally opened switch S-5 are in shunt across contacts K3-I and K4-1 and are developer bypass and fixer bypass switches, respectively. Upon depression of either of these switches, the respective replenisher pump is activated independently of the timers.
The scanner-timer which determines the rate at which the input signal from the photo-cell is received by the integrator 10, is iniiated by an external film switch, F8. The film switch FS is responsive to the speed of the film fed through the processor. On the output of scanner-timer 60 is relay K-I which, as noted before, closes contacts KI-2 to pass the signal to the integrator l0 and resets relay K-2 and switching transistor Q-ll through contacts Kl-l. As with timer 40 and 50, the period of the scanner is adjusted by the variable resistor 62.
The DC voltages shown throughout the schematic for exposure scanner and replenisher control 100 are pro vided. by power supply 70. AC external power is applied over lines L1 and L2 to transformer T-1 through on-off-test switch Sl-A. The AC power from transformer T-I is rectified through diodes D-l through D-4 and a 24-volt DC level is obtained at output point 72. The +16 volt DC and the l6 volt DC levels are obtained at points '74 and 76, respectively.
Additional electronic circuitry external to the exposure scanner and replenisher unit 100 is shown in FIG. 4. The two relays, R-2 and R-5 in FIG. 4, control contacts R2-1, RS-l, and R5-2, respectively, which are shown in FIG. 3. Referring now to FIG. 4, the power supply is supplied across lines L-l and L-2. The air switch film sensor, which is shown in FIG. 1 at the entrance to the first developing bath, controls the condition of normally open air switch AS-l and normally closed air switch AS-2 which detect the trailing and leading edge of the film to be processed, respectively. As long as film is being fed into the first developing bath, air switch film sensor closes switch As-2 which sends a signal to input 96 of drift lock-out timer to indicate that the air switch film sensor has detected the leading edge of the film to be processed.
Drift lock-out timer 90 is powered from lines L-ll and L2 through terminals 92 and 94, respectively. From the time drift lock-out timer 90 is initiated at terminal 96 until it times out approximately 6 minutes, drift lock-out relay R5 is activated. Activation of this relay closes contacts RS-l and R5-2, shown in FIG. 3. RS-l activates relay K-S in FIG. 3 which closes contact K5l to pass the photocell signals into integrator 10. Contacts R5-2, which also are closed during the time cycle or period of drift lock-out timer 90, connects the power to developer replenisher pump once contacts K3-1 are closed from the activation of developer pump-timer 40.
In parallel with the drift lock-out timer terminal 96 is a double replenisher circuit, including double replenisher relay R-2 and double replenisher switch 5-6. As long as air switch AS2 is closed in response to a film being present in the air switch film sensor, and double replenished switch AS-6 is momentarily closed, relay R-Z is activated to close latching contacts R2-2 to keep relay R-Z activated as long as switch AS2 is closed. Also controlled by double replenisher relay R-2 is switch contacts R2l, shown in FIG. 3. When switch contacts R2-l are closed, double replenisher adjust resistor 24 is introduced into the photocell circuit. The introduction of the voltage divider modifies the signal from the photocell to the integrator 10. By proper adjustment of the resistor 24, the signal to the integrator will appear twice its normal exposure, and cause twice the normal amount of replenishment.
Once the trailing edge of the film has passed through the air switch film sensor, air switch AS-l is closed which activates timer motor TM. Upon activation of timer motor TM, normally closed switch TMS is held open for the duration of the timer motor. Six minutes after the trailing edge of the film has allowed switch contacts AS-1 to close, the timer motor TM times out and switch contacts TMS assume their normally closed position and activate bell B.
An example of a timer which may be used as developer pump-timer 40, fix pump-timer 50, or scannertimer 60 is shown schematically in FIG. 5. The timer is basically a one-shot multi-vibrator made up of transistors -2 and 0-3 and a unijunction transistor UJT. Upon the application of an input pulse at the input, transistor 0-3 changes from the conductive to the nonconductive state and transistor Q-2 changes from the nonconductive to the conductive state. Upon the conducting of transistor Q-2, relay R is activated. When Q-3 changes state from the conductive to the nonconductive, the charging path for capacitor C is established through fixed resistor R and variable resistor AR. When the voltage across the capacitor C reaches a certain level, the uni-junction transistor UJT is triggered, discharging the capacitor and resetting transistors Q2 and Q3 to their initial state. The time period of each of the timers may be varied by the adjustment of adjustable resistor AR.
Before the exposure scanner and replenishment control circuit 100 is used, adjustments are made using a clear piece of film. The input signals from this photocell are balanced against an adjustable reference signal using the clear piece of film. Then when an exposed film is between a light source and the photocell, the difference between the reference voltage and the photocell signal represents the exposure of the film. It is this difference signal that is integrated by integrator 10.
Referring now to FIGS. 1, 3 and 4, the operation of the exposure scanner and replenishment control will be explained. initially, relay R5 is deactivated and consequently contacts R5-l are open. Thus relay K-S is open, preventing any signal from being passed from the photo-cells to the integrator 10. This is accomplished by the normally open contacts KS-ll. This locks out or prevents any drift signal from being introduced into the system into the integrator. Upon the insertion of the film from the feed table into the first developing bath through air switch film sensor, air switch AS2 is closed. This initiates drift lock-out timer which activates relay R-S to close its respective contacts RS-l and R5-2. Depending on whether additional replenisher is to be added by activation of switch 5-6, the state of the double replenisher relay R-2 and its respective contacts are determined.
As the film passes between fluorscent light LS and photocells PC-l through 4, the entire width of the film is scanned and an electrical signal proportional to the density of exposure is provided to integrator 10. Cpntacts KIT-2 and K51 are closed due to the activation of relay [(-1 at the output of scanner-timer 60 and relay K-S, the drift lock-out relay, respectively. The initiation of the scanner-timer 60 is determined by film switch FS which is responsive to the film speed. Each time the switch FS is actuated, the photocell signal is measured for a preset time determined by scannertimer 6% and variable resistor 62. The timer setting and rate of switch activation are selected so that the entire surface of the film is scanned during the scanning period at maximum film transport speed. Thus the period of scanner-timer 60 must be shorter than the maximum frequency of the closure of switch PS. The integrator it) integrates the photocell signals and provides a voltage output proportional to the cumulative amount of exposure of the film as it passes over the photocells. This cumulative exposure or density is indicated on meter 20 and is passed to a threshold detector.
The threshold detector 30 determined when the cumulative film exposure has reached a preset level determined by master replenish control and resistor 38. At this point an output signal is provided to start the developer pump-timer 40 and fixer pump-timer 50. Upon the initiation of these timers, relays l(3 and (-4 are activated to close the respective contacts K34 and 103-1 to send AC power to the developer replenisher pump and fixer replenisher pump, respectively. Also activated by the output of threshold detector 30 is transistor switch 0-1 which activates automatic reset relay K-Z to reset the integrator 10 and thus remove the signal from threshold detector 30. Switching transistor 0-11 and the integrator W may also be reset by manual reset switch 82-8 and S2A, respectively. Also provided in the developer replenisher pump circuit and the fixer replenisher pump circuit are bypass switches 8-4 and 8-5, respectively. Upon activation of the developer replenisher pump and the fixer replenisher pump, indicator lights 1-H and 1-2 are ignited.
Provided in the circuitry between the photo-cells and the integrator circuitry K0 is a test switch which bypasses the scanner timer controlled contacts Kl-Z. This allows for adjustment and test of the system without the activation of scanner-timer 60.
Though the preferred embodiment of the exposure scanner and the replenisher control circuit has been described using a Schmitt trigger as a threshold detector,
vides an accurate measurement and efficient replenishment of photographic chemicals to insure proper functioning of an automatic photographic film processor. Obviously many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.
What is claimed is: i
1. Exposure scanner for a photographic film processor comprising:
scan sensor means for monitoring instantaneously a width of film and for producing an electrical signal proportional to the density of exposure;
integrator means for integrating said scan sensor means electrical signal and for producing an output proportional to the cumulative amount of exposure;
threshold sensing means for determining a preset level of the cumulative exposure signal and for producing an output signal when said level is reached;
indicator means responsive to said threshold sensing means output to indicate that a preset level of exposure has accumulated;
film switch means responsive to the rate at which said film moves for producing an output pulse; timer means responsive to said output pulse for producing an output for a predetermined period; and
scanner switch means responsive to said timer means output for connecting said scan sensor means elecrical signal to said integrator means during said predetermined period, and physically disconnecting said scan sensor means electrical signal from said integrator means at all other times.
2. An exposure scanner as in claim 1 further including automatic reset means responsive to said threshold sensing means output to reset said integrator means.
3. An exposure scanner as in claim 2 wherein:
said integrator means is an operational amplifier with capacitative feedback; and
said threshold sensing means is a Schmitt trigger.
4. An exposure scanner as in claim 1 wherein:
said scan sensor means includes a light source means and photo-cell means for scanning the entire width of film; and
said predetermined period of said timer means is shorter than the frequency of said output pulse.
5. An exposure scanner as in claim 1 further including:
film sensor means for sensing the presence of photographic film to be processed; and
drift lockout means responsive to said film sensor for disconnecting said scan sensor means from said integrator means a predetermined time after said photographic films presence is sensed. 6. An esposure scanner and replenisher control for a photographic processor comprising:
a scan sensor means for monitoring instantaneously a width of developed film and for producing a signal proportional to the density of exposure;
integrator means for accumulating said exposure density signal; scan timer means responsive to film speed for connecting said scan sensor means signal to said integrator means for a predetermined period;
threshold means for detecting a preset level of said accumulated exposure density signal and for producing an output when said preset level is detected; and
control means for controlling the replenishment of photographic solutions in response to said threshold means output.
7. An exposure scanner and replenisher control of claim 6 wherein said control means includes replenishment timer means for allowing replenishment for a predetermined time in response to said threshold means output.
8. An exposure scanner and replenisher control of claim 7 wherein said control means includes two of said replenishment timer means, one for developer solution and one for fixer solution; and
replenishment periods of said replenishment timer means which are individually adjustable in duration. 9. An exposure scanner and replenisher control as in claim 6 further including automatic reset means responsive to said threshold sensing means output to reset said integrator means.
10. An exposure scanner and replenisher control of claim 6 wherein said scan sensor means includes a switch means for modifying, when activated, said density exposure signal so that the amount of replenishment is changed by a predetermined amount.
11. An exposure scanner and replenisher control of claim 8 wherein each of said replenishment timer means includes a bypass switch means for additional replenishment if activated.
12. An exposure scanner and replenisher control as in claim 6 further including:
film sensor means for sensing the leading or trailing edge of photographic film to be processed; and
lockout means for disconnecting said scan sensor means from said integrator means a predetermined time after said film sensor means senses said leading edge.
13. An exposure scanner as in claim 12 further comprising:
indicator means for indicating when another photographic film may be inserted into said processor; and
indicator control means for initiating said indicator means a predetermined time after said film sensor means senses said trailing edge.