Automatic Anti-Oxidation Replenisher Control

Reference is hereby made to a co-pending application, Ser. No. 168,019, entitled AUTOMATIC REPLENISHER CONTROL SYSTEM filed on even date herewith and assigned to the same assignee as this application.

1. Field of the Invention

The present invention relates to an anti-oxidation replenisher control system for use in processors of photosensitive material.

2. Description of the Prior Art

Automatic photographic film and paper processors transport sheets or webs of photographic film or paper through a sequence of processor tanks in which the photosensitive material is developed, fixed, and washed, and then transports the material through a dryer. It is well known that photographic processors require replenishment of the processing fluids to compensate for changes in the chemical activity of the fluids.

First, it has been recognized that replenishment is necessary to replace constituents used as photosensitive film or paper is developed in the processor. This replenishment is "use related" or "exhaustion" chemical replenishment. Both developer and fix solutions require exhaustion replenishment.

Second, chemical activity of the developer solution due to aerial oxidation occurs with the passage of time regardless of whether film or paper is being processed. Some replenishment systems provide additional replenishment of an "anti-oxidation" (A-O) replenishment solution which counteracts this deterioration.

Replenishment systems were originally manually operated. The operator would visually inspect the processed film or paper and manually operate a replenisher system as he deemed necessary. The accuracy of the manual replenisher systems was obviously dependent upon the skill and experience of the operator.

Various automatic replenishment systems have been developed for providing use-related replenishment. Examples of these automatic replenishment systems include U.S. Pat. Nos. 3,472,143 by Hixon et al; 3,529,529 by Schumacher; 3,554,109 by Street et al; 3,559,555 by Street; 3,561,344 by Frutiger et al; 3,696,728 by Hope; 3,752,052 by Hope et al; 3,787,689 by Fidelman; 3,927,417 by Kinoshita et al; 3,990,088 by Takita; 4,057,818 by Gaskell et al; 4,104,670 by Charnley et al; 4,119,952 by Takahashi et al; 4,128,325 by Melander et al; and 4,134,663 by Laar et al. Examples of prior art replenisher controls for providing both exhaustion and anti-oxidation replenishment are shown in U.S. Pat. Nos. 3,822,723 by Crowell et al and 4,174,169 by Melander et al.

The automatic control system of the present invention recognizes that generally a processor of photosensitive material is not operated on a continuous twenty-four hour basis. Oxidation of the replenisher solution, however, continues even during nonoperating hours of the processor. The control system of the present invention provides anti-oxidation replenishment so that the developer solution will have the desired chemical activity when normal operation of the processor commences again after a period of nonoperation.

The control system of the present invention includes a real time clock for providing an indication of the time of day, and means for storing a schedule of operating hours of the processor. The control system controls anti-oxidation replenishment as a function of the time of day and the schedule of operation.

In one embodiment of the present invention, the control system provides anti-oxidation replenishment on a twenty-four hour basis (even during nonoperating hours) by operating a developer circulation pump and an anti-oxidation replenishment pump on a periodic basis during nonoperating hours.

In another embodiment of the present invention, which is particularly useful when there are restrictions against leaving on the electrical power to the processor during nonoperating hours, the control system adds a bulk amount of anti-oxidation replenishment at the time of turn-off of the processor. This bulk amount of anti-oxidation replenishment is a function of the time at turn-off and the next scheduled turn-on time.

The FIGURE is a block diagram illustrating a preferred embodiment of the automatic anti-oxidation replenishment control system of the present invention.

In the system shown in the FIGURE, a photographic processor includes developer tank 10, fix tank 12, wash tank 14, and dryer 16. Film transport drive 18 transports the strip or web of photosensitive material (either film or paper) through tanks 10, 12, 14 and dryer 16. Microcomputer 20 controls operation of film transport 18 and of the automatic replenishment of fluids to tanks 10, 12 and 14.

The auto-replenishment system shown in the FIGURE includes developer replenisher 21a and anti-oxidation replenisher 21b for providing exhaustion and anti-oxidation replenishment, respectively, to developer tank 10. In addition, the system includes fix replenisher 21a for providing fix replenishment to fix tank 12, and wash replenisher 21d for providing wash replenishment to wash tank 14.

Developer replenisher 21a includes exhaustion replenishment reservoir 22, pump 24, pump relay 26, and flow meter or switch 28. Exhaustion replenishment for developer tank 10 is supplied from exhaustion replenishment reservoir 22 by means of pump 24. Microcomputer 20 controls operation of pump 24 through pump relay 26. Flow meter or switch 28 monitors the exhaustion replenishment fluid actually pumped by pump 24 to developer tank 10, and provides a feedback signal to microcomputer 20.

Anti-oxidation replenisher 21b includes A-O replenisher reservoir 30, pump 32, pump relay 34, and flow meter or switch 36. Anti-oxidation replenishment is supplied from A-O replenisher reservoir 30 to developer tank 10 by pump 32. Microcomputer 20 controls operation of pump 32 by means of relay 34. Flow meter or switch 36 monitors flow of A-O replenishment to developer tank 10 and provides a feedback signal to microcomputer 20.

Also shown in the FIGURE is developer circulation pump 37, which circulates the developer solution within developer tank 10. Microcomputer 20 controls operation of developer circulation pump 37.

Fix replenisher 21c includes fix replenisher reservoir 38, pump 40, pump relay 42, and flow meter or switch 44. Fix replenishment is supplied to fix tank 12 from fix replenisher reservoir 38 by pump 40, which is controlled by microcomputer 20 through relay 42. Flow meter or switch 44 monitors flow of replenishment fluid to fix tank 12, and supplies a feedback signal to microcomputer 20.

Wash replenisher 21d, which includes wash reservoir 46, pump 48, pump relay 50, and flow meter or switch 52, provides replenishment of wash fluid (typically water) in wash tank 14. The wash fluid is supplied from wash replenishment reservoir 46, and is pumped to wash tank 14 by pump 48. Microcomputer 20 controls pump 48 through relay 50, and monitors the flow of wash replenishment to tank 14 by means of flow meter or switch 52.

Microcomputer 20 utilizes developer counter 56, A-O counter 57, fix counter 58, and wash counter 59 as timers to control replenishment. When, for example, exhaustion replenishment is required, microcomputer 20 loads a numerical value (DEVTIME) into developer counter 56, which then begins counting. Microcomputer 20 energizes relay 26, which actuates pump 24. When developer counter 56 reaches a predetermined value (such as zero), it provides an interrupt signal to microcomputer 20, which de-energizes relay 26. The numerical value (DEVTIME), therefore, determines the total amount of exhaustion developer replenisher pumped into tank 10.

Counters 57, 58 and 59 are operated in a similar manner. The numerical values loaded into counters 57, 58 and 59 are hereafter referred to as AOXTIME, FIXTIME and WASHTIME, respectively.

AOX timer 60 is a free running timer which provides an interrupt signal to microcomputer 20 on a periodic basis to initiate A-O replenishment. In one preferred embodiment, AOX timer 60 provides the interrupt signal every 22.5 minutes.

Microcomputer 20 also receives signals from film width sensors 62 and density scanner 64. Film width sensors 62 are positioned at the input throat of the processor, and provide signals indicating the width of the strip of photosensitive material as it is fed into the processor. Since microcomputer 20 also controls film transport 18, and receives feedback signals from film transport 18, the width signals from film width sensors 62 and the feedback signals from film transport 18 provide an indication of the area of photosensitive material being processed.

Density scanner 64 senses density of the processed photosensitive material. The signals from density scanner 64 provide an indication of the integrated density of the processed photosensitive material. The integrated density, together with the area of material processed, provides an indication of the amount of processor fluids used in processing that material.

Microcomputer 20 also receives signals from control panel 66, which includes function switches 68, keyboard 70, and display 72. Function switches 68 select certain functions and operating modes of the processor. Keyboard 70 permits the operator to enter numerical information, and other control signals used by microcomputer 20 in controlling operation of the processor, including replenishment. Display 72 displays messages or numerical values in response to control signals from microcomputer 20.

The A-O replenishment control system of the present invention includes real time clock 74 and mix timer 75. Real time clock 74 maintains the time of day, and preferably is provided with battery backup power so that it continues to operate even when power to the processor is turned off. Mix timer 75 controls the running time of developer circulation pump 37 during non-operating hours of the processor to provide mixing of the developer solution when A-O replenishment is provided during non-operating hours in accordance with the present invention.

Microcomputer 20 preferably stores set values for each of a plurality of photosensitive materials that may be processed in the processor. Each group of set values includes pump rates for pump 24 (DEVMRATE), pump 32 (AOXPMPRTE), pump 40 (FIXPMPRTE) and pump 48 (WASHPMPRTE); desired replenishment rates of exhaustion developer (DEVRATE) A-O replenishment (AOXRATE), fix replenishment (FIXRTE), and wash replenishment (WASHRATE).

When operation is commenced, the operator selects one of the groups of set values which corresponds to the particular photosensitive material being processed. As the leading edge of each strip of photosensitive material is fed into the processor, film width sensors 62 sense the presence of the strip, and provide a signal indicative of the width of the strip being fed into the processor. Width sensors 62 continue to provide the signal indicative of the width of the strip until the trailing edge of the strip passes sensors 62. The length of time between the leading and trailing edges of the material passing sensors 62, and the transport speed of the material (which is controlled by microcomputer 20 through film transport 18) provide an indication of the length of the strip. The width and length information for each strip is stored until the strip has been transported through the processor and reaches density scanner 64. The area of the strip and the integrated density of the strip (which is provided by the signals from density scanner 64), provide an indication of the amounts of developer and fix which have been exhausted in processing that particular strip.

The present invention is an improved system for automatically controlling A-O replenishment. For that reason, a detailed description of developer exhaustion, fix, and wash replenishment is not provided in this application. Reference may be made to the previously mentioned co-pending patent application entitled "Automatic Replenisher Control System" for further details.

The anti-oxidation replenishment takes one of two forms, depending upon the particular developer chemistry used. One type of anti-oxidation replenishment is known as "blender chemistry", and the other type is known as "dual" or "two-part chemistry".

Blender chemistry is based upon a "minimum daily requirement" of anti-oxidation replenishment. This minimum daily requirement is dependent upon the amount of aerial oxidation which occurs in developer tank 10, which in turn is dependent upon the surface area of tank 10, the operating temperature of the developer solution, and a number of other factors. With blender chemistry, some anti-oxidation replenishment is provided each time exhaustion replenishment occurs. The more exhaustion replenishment provided, the less separate anti-oxidation replenishment is required.

Two-part chemistry, on the other hand, is independent of exhaustion replenishment. Two-part chemistry replenishment is based upon a daily requirement of anti-oxidation replenishment, which is unaffected by the amount of material processed in the processor and the amount of exhaustion replenishment provided.

The replenishment control system of the present invention controls anti-oxidation replenishment on the basis of 22.5 minute intervals. During a twenty-four hour day, there are sixty-four intervals of 22.5 minutes each. AOX timer 60 provides interrupt signals to microcomputer 20 at the 22.5 minute intervals.

In the case of blender chemistry replenishment, microcomputer 20 adjusts the amount of anti-oxidation replenishment at the end of each 22.5 minute interval as a function of the amount of exhaustion replenishment which was provided during the 22.5 minute interval. If no film or paper has been run through the processor during the 22.5 minute interval, so that no exhaustion replenishment has occurred, microcomputer 20 actuates relay 34 to run pump 32 for a time period sufficient to provide 1/64th of the minimum daily requirement. If exhaustion replenishment has occurred during the 22.5 minute interval, microcomputer 20 reduces the operating time of pump 32 accordingly. If film or paper is being processed at a high enough rate during the 22.5 minute interval, no blender anti-oxidation replenishment is required, and microcomputer 20 does not activate pump 32.

In the case of two-part chemistry, microcomputer 20 actuates relay 34 at the end of each 22.5 minute interval. Relay 34 is energized for a period long enough to permit pump 32 to pump 1/64th of the daily requirement of two-part chemistry replenishment.

Anti-oxidation replenishment is real time dependent, not simply operating time dependent. In other words, aerial oxidation of the developer solution continues even during those hours that the processor is turned off and no material is being processed. This, of course, is the usual situation in many business--the the processor is not operated at night or on the weekends.

The problem which can be encountered with extended nonoperating periods is that the chemical activity of the developer solution continues to degrade due to aerial oxidation. When the processor is again started, the chemical activity of the developer solution is out of range, and it takes some time before the developer solution can be replenished to a point at which it can be used. This results in lost production time at the beginning of each day.

In general, the longer the period in which the processor is not operated, the greater the amount of aerial oxidation which can occur. When the processor is not used over a weekend, the problem can be even worse than when the processor is not used overnight.

The anti-oxidation replenishment control system of the present invention solves these problems by use of real time clock 74, which maintains the current time of day. Microcomputer 20 stores an operating schedule for the processor for each day of the week. In the preferred embodiment, this operating schedule is in terms of a TIMEON time and a TIMEOFF time for each day of the week. This schedule of operating and nonoperating times is entered into microcomputer 20 by the operator through keyboard 70.

In some facilities, there are restrictions against leaving power on to the processor during nonoperating hours. In this type of situation, the present invention pre-replenishes anti-oxidation replenishment before shut-down and also preferably compensates on power up for any down time which was not taken into account by pre-replenishment at shut-down. In this embodiment, a POWER switch (not shown) is included among function switches 72. At the end of the operating day, the operator switches the POWER switch initially to "standby". When this occurs, microcomputer 20 receives a high priority interrupt. It then calculates the bulk amount of anti-oxidation replenishment which should be added as a function of the actual time of day (ACTIME) and the next schedule time (TIMEON) when the processor will be turned on. Microcomputer 20 then calculates AOXTIME, which is loaded into anti-oxidation counter 57 and energizes relay 34. When counter 57 reaches zero, pump 32 is turned off, thereby ending the bulk anti-oxidation replenishment. At the end of this bulk addition, the processor is ready to be shut down for the night or the weekend.

When the processor is initially turned on, the POWER switch is first turned to the standby position. Once again microcomputer 20 calculates the bulk anti-oxidation replenishment based upon the difference, if any, between the actual time (ACTIME) and the previously scheduled TIMEON time. In other words, if the processor had been turned off for longer than what was scheduled, so that further bulk anti-oxidation replenishment is necessary to re-establish the desired developer chemical activity, microcomputer 20 determines the amount of bulk anti-oxidation replenishment necessary and adds that amount.

When there are no restrictions at the processor installation point against continuously leaving the processor with a live electrical input (i.e. even during normal nonoperating hours), the anti-oxidation replenishment system of the present invention replenishes on a real time twenty-four hour schedule. If the processor is not being used, microcomputer 20 activates developer circulation pump 37 and anti-oxidation replenishment pump 32 as required. After a suitable circulation time, microcomputer 20 turns off pumps 32 and 37 and shuts down the processor until the end of the next interval (e.g. 22.5 minutes) when anti-oxidation replenishment is again provided.

In this preferred embodiment of the present invention, microcomputer 20 also preferably turns the processor on in the morning and off at night. The turn-on time is preferably selected so that the processor is replenished, up to temperature, and ready for operation at the beginning of the normal work day.

When extended nonoperating periods are scheduled, such as over a weekend, microcomputer 20 also preferably adjusts either the bulk additions or the periodic additions of anti-oxidation replenishment accordingly. Since extended nonoperating periods normally mean that the temperature of the developer solution will eventually reach room temperature, the rate of aerial oxidation will be affected, since it is temperature dependent. In one preferred embodiment, microcomputer 20 determines whether the nonoperating period exceeds twenty-four hours. In the event that it does exceed twenty-four hours, the replenishment rate (AOXRTE) for the bulk additions or the periodic nonoperating hours replenishment is divided in half.

Table B illustrates how microcomputer 20 determines and controls anti-oxidation replenishment for both during normal operating hours and nonoperating hours. Step B.15 is specifically concerned with the embodiment of the present invention in which bulk additions are made prior to shut-down and upon power up of the processor. Step B.17 is concerned with the embodiment of the present invention in which anti-oxidation replenishment continues at 22.5 minute intervals on a twenty-four hour basis, even throughout the nonoperating hours.

B.1 AOX timer 60 times out (22.5 min) (free run)

B.2 If BLENDER chemistry then

(1) AOXREPL=(AOXRATE.div.64)-AOXDEV

(2) Reset AOXDEV

else AOXREPL=AOXRATE.div.64 (i.e. if TWO-PART chemistry)

B.3 AOXTIME=AOXREPL.div.AOXPMPRTE+AOXMINRUN

B.4 If AOXTIME less than 7.5 seconds then

(1) Calculate AOXMINRUN=AOXMINRUM+AOXTIME

(2) Return to B.1

B.5 Output AOXTIME to counter 57

B.6 Trigger pulse sent to counter 57 and

(1) Replenish flag (AOX) set

B.7 Counter 57 begins decrementing and

(1) Anti-ox replenishment pump 32 runs

B.8 If flow switch 36 does not activate and/or Anti-ox replenishment pump relay 34 does not energize then ERROR

B.9 If pump enable is turned off while counter 57 is running then

(1) Wait 5 seconds

(2) If change then resume B.8 else

(3) Read value remaining in counter 57 to AOXREM

(4) Clear counter 57

(5) Replenish flag (AOX) reset

(6) Return to B.1

B.10 Counter 57 times out and

(1) Interrupt request generated

B.11 If interrupt request not acknowledged then wait; else

B.12 If flow switch 36 remains activated and/or pump relay 34 remains energized then ERROR; else

B.13 Reset replenish (AOX) flag and AOX not complete flag and clear AOXMINRUN

B.14 Return to B.1 or if TIMEOFF to B.17 (1)(c)

B.15 If POWER switch changes to STANDBY then

(1) Turn on ANTI-OX replenishing light

(2) Generate high priority interrupt (set AOX not complete flag)

(3) Calculate BULKAOX=(TIMEON-ACTIME)* (AOXRTE.div.144)

(4) Calculate BULKTIME=BULKAOX.div.AOXPMPRTE

(5) If BULKTIME is less than 7.5 seconds then

(a) Clear BULKTIME

(b) Clear BULKAOX

(c) Turn off ANTI-OX replenishing light

(6) Calculate AOXREPL=BULKAOX

(7) Calculate AOXTIME=BULKTIME

(8) Return to B.5

B.16 If POWER switch changes to OFF and

(1) AOX not complete flag is set then

(a) Maintain AOX replenishing light from battery

(b) Sound SONALERT for seconds else nothing

B.17 If TIME-OFF and

(1) AOX timer 60 times out then

(a) Turn on developer circulation pump 37

(b) Go to B.2

(c) Start MIXTIMER 75

(d) When MIXTIMER 75 times out then

(i) Turn off developer circulation pump 37

(ii) Return to B.17

The anti-oxidation replenishment control system of the present invention stores operating schedules of the processor and maintains an actual time of day. With this information, the control system controls anti-oxidation replenishment to maintain the desired chemical activity of the developer solution despite prolonged scheduled nonoperating periods of the processor. The present invention is capable of providing this anti-oxidation replenishment in either the case where the processor electrical power is turned off at the end of the day, and in the case where power can remain on to the processor on a continuous basis, even though the processor itself is not operating.

With the present invention, therefore, delays beginning with a day in order to bring the chemical activity of the developer solution back into the desired range are substantially reduced. This can significantly reduce lost production time.

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.