US3559555A

US3559555A - Image monitoring and control system

Info

Publication number: US3559555A
Application number: US734297A
Authority: US
Inventors: John N Street
Original assignee: John N Street
Current assignee: AFP ACQUISITION Corp
Priority date: 1968-06-04
Filing date: 1968-06-04
Publication date: 1971-02-02
Anticipated expiration: 1988-02-02
Also published as: JPS4941823B1; NL6901283A; BE727729A; GB1213941A; CH508901A; NL144740B

Abstract

A system is provided for automatically controlling chemical replenishment in a chemical-containing automatic film processor. As sheets of varying density image bearing material are transported through the processor, the varying density images in each of said sheets are optically monitored throughout substantially the entire width and length of each sheet. Information is stored relating to the aggregate image density in the monitored sheets; and a preselected quantity of replenishment chemical is supplied to the processor when the aggregate image density reaches a predetermined value.

Description

XR Bet- 5995555 United States I atcul. 3,559,555

[72] Inventor John N. Street 3,345,928 10/1967 Krehbiel 95/94 sg z g Va. FOREIGN PATENTS [21] AppLNo. 4, 7 [22] ile J 1968 1,105,476 3/1968 Great Britain 95/89 [45 Patented Feb. 2, 1971 Primary Examiner-John M Horan [73] Assignee Logetronics Inc. Assistant Examiner-Robert P. Greiner S in field V Attorneys-William D. Hall, Elliott l. Polock, Fred C. Philpitt,

George Vande Sande, Charles F. Steininger and Robert R. Priddy [54] IMAGE MONITORING AND CONTROL SYSTEM 14 Claims, 5 Drawing Figs. [52] U.S.Cl 95/89, ABSTRACT: A System is provided for automatically 95/941 350/96 trolling chemical replenishment in a chemical-containing au- [51] Int. Cl 603d 3/00, tomatic fil processor AS sheets of y g density image 603d 3/06 bearing material are transported through the processor, the [50] Field of Search 95/89, 94; varying density images in each f Said sheets are optically 350/96 monitored throughout substantially the entire width and [56] References Cited length of each sheet. information is stored relating to the aggregate image density in the monitored sheets; and a UNITED STATES PATENTS preselected quantity of replenishment chemical is supplied to 1,895,760 l/1933 Hunt 95/89 the processor when the aggregate image density reaches a 2,296,048 9/1942 Planskoy 95/89 predetermined value.

LIGHT SCANNER ii; I? a fi 2o PK 7 l6 DRIER l9 11 CONTROL 0 CIRCUIT I I4 l4 RESERVOIR f DEVELOPER l 22 25 23 TANK FlXER TANK WASH TANK 24 VALVE FLOWMETER r a Ma.

PATENTEU r552 19?: 3,559,555

SHEET 2 UF 2 EICGAHNTNER I? CONT /CIRC RESERVOIR f J DEVELOPER 1 F V 22 25 23 TANK FIXER) TANK wAsH TANK VALVE FLOWMETER FIG. 3A

INVENTOR JOHN N. STREET ATTORNEY IMAGE MONITORING AND CONTROL SYSTEM BACKGROUND OF THE INVENTION Various forms of automatic processors adapted to develop, fix, wash and dry sheets of photosensitive material are already known to those skilled in the art. In such processors, a sheet of photosensitive material to be processed is fed in sequence from one processor tank to the next; and the developed, fixed and washed material is then automatically passed through a drier and collected. In the normal operation of such processors, the chemicals employed for processing the photosensitive material tend to become depleted as sheets of such material are processed; and unless some form of chemical replenishment is effected during continued operation of the processor, there will be severe degradation in the image quality of the films being developed. It is, accordingly, customary to include some form of controllable replenishment facility in automatic film processors, intended to maintain chemical concentrations in the processor tanks at desired levels, or within desired limits.

One form of replenishment system already known to those skilled in the art constitutes a manually operable control adapted to open solenoid controlled valves for a desired time interval. The solenoid controlled valves are positioned between tanks of replenishing chemicals and the processor developer and fixer tanks, so that various amounts of replenishment chemicals can be added to the processor tanks in accordance with visual estimates made by the operator of the processor equipment. These visual estimates are, in turn, normally made by the operator of the equipment on the basis of the film size and degree of exposure of the particular sheet of film to be processed; and the operator of the equipment normally dials in or otherwise manually controls the amount of replenishment chemical which he estimates to be needed for each sheet of material processed.

The accuracy of manual replenishment controls of the types described above is less than may be desirable since it depends in large part upon a rough visual estimate made by the operator of the equipment. Any errors in such an estimate may be cumulative over a period of time; and, as a result, no one can be sure of the chemical activity of the processor solutions after an extended period of operation and manual replenishment. In order to confirm the state of the processor solutions after a period of time, it is accordingly also customary to pass socalled process control strips having precisely exposed latent images thereon, through the processor. After processing, these strips are analyzed densitometrically and the readings obtained are used to maintain a process control chart which will show trends and changes in processor performance. Such charts normally include plots of two types of information, i.e.,

the developer speed which is indicative of the maximum.

density to which an image having a given exposure will develop, and the gradient" which is indicative of the developed image contrast. The objective of the process control chart is to monitor trends in these two factors, so that by controlling replenishment, an attempt can be made to keep both factors within acceptable limits.

When process control strips are employed, the accuracy of replenishment is related to the frequency with which such strips are run, the skill of the operator in preparing and interpreting the process control chart, and his ability to control replenishment to counteract observed trends. Obviously, if process control strips are run only at relatively widely spaced time intervals, it is difficult to know what the trends are. Therefore, assuming that the operator is sufficiently skilled to compensate for observed trends, an ideal situation would require that a process control strip be run with practically every sheet of film being developed. This, however, is so costly and time consuming as to be economically impractical. A compromise is, therefore, often struck and process control strips are run every hour or the-like. On the basis of the information gained by obtaining and plotting data from such process control strips, the operator of the manual replenishment system tries, within the limits of his expertize, either to increase or decrease (or he eliminates) replenishment in an effort to counteract observed trends.

Manual replenishment systems of the types described above are capable of keeping the processor within desired control limits over a period of time. The very nature of this type of replenishment activity is, however, time consuming and expensive; and its feasibility is largely dependent upon the skill of the operator in guessing just what is happening to the chemical solutions in the processor, and in determining just what action is needed to counteract and control observed trends. In addition, such manual replenishment techniques are impractical when it is necessary to control a film processor equipped with an automatic sheet or roll feeding device, e.g., a feeder of the type disclosed in US. Pat. No. 3,232,606.

In an effort to overcome some of the difficulties of manually controlled replenishment systems, suggestions have been made heretofore for so-called automatic replenishment systems. In such automatic systems, some form of sensor is employed to monitor a preselected parameter or parameters; and on the basis of the output of this sensor, an attempt is made to effect appropriate chemical replenishment. In some cases, the sensor is designed to optically read a continuous control strip passed through the solution, or to monitor one or more preexposed test regions of a sheet of film being processed. As a practical matter, systems of this type involve substantially all of the disadvantages described previously, i.e., complexity, etc. Moreover, notwithstanding these disadvantages, prior such automatic systems effect relatively inaccurate replenishment since the information obtained from the sensing or monitoring operation does not truly indicate the character of the image throughout an individual sheet of film being processed, or the character of the image in every sheet being processed, or the amount of chemical which may or will have been used up in the course of processing any one or a plurality of film sheets.

Other so-called automatic replenishment systems suggested heretofore have sought to monitor the physical level of the processor solutions, and to effect replenishment by the use of float control valves or the like; but systems of this type do not reflect what is actually happening to the chemistry of the solutions at all, and merely maintain given volumes of solution rather than desired chemical concentrations. Still other prior systems have sensed the physical size of a sheet of film being processed, and have sought to control replenishment on the basis of the area of material being processed. Such systems, however, are also highly inaccurate since the amount of .chemical replenishment required is not a function of film area per se, but is primarily a function of exposed" film area. Sizedetecting systems therefore fail to-determine the amount of chemicals which has actually been used, and fail to supply information needed to maintain chemical concentrations within desired limits.

The present invention, recognizing these disadvantages of manual replenishment systems and so-called automatic systems suggested heretofore, provides a new and far more accurate automatic replenishment system adapted to compensate for chemical depletion as a function of the optical density developed in every sheet of image bearing photosensitive material being processed, and as a function of the optical density throughout the complete are of each such sheet of material.

SUMMARY OF THE INVENTION The present invention comprises an apparatus adapted to determine the image density variations throughout the complete area of a film sheet after it has been developed in an automatic processor, and arranged to generate an electronic signal commensurate with the monitored image density. In this respect, the term sheet used herein and in the appended claims is intended to encompass both continuous and cut lengths of material, and the term film is intended to encompass any suitable type of material requiring processing. The complete areal image density variations of the film sheet, thus monitored, provides a more accurate measure of the degradation of the developer and fixer solutions in the automatic film processing equipment; and the signal generated as a result of the monitoring operation may accordingly be employed to control proper replenishment of the developer and fixer solutions on an automatic basis.

In effecting the foregoing functions, the present invention employs a scanning system comprising a plurality of bundles of optical fibers which are serially illuminated or scanned by a light source, operative to cause an elongated, narrow beam of light to traverse the complete width of a sheet of film after the film sheet has been developed. Light passing through the developed film is detected by a linear array of optical fibers located on the opposite side of the film; and the detected light is then summed in a photocell or like means. The steady state photocellcurrent is balanced to zero (or'to a predetermined steady state value) by means of a current of suitable magnitude and polarity from an external circuit so that the output of the photocell (or any other appropriate means, such as a photomultiplier tube) remains at a known steady state value until the sensor light is attenuated by the passage of imagebearing material.

The photocell is coupled to a first information accumulator or integrator adapted to produce a signal commensurate with the developed areas sensed on the film during a single scan of the film sheet by the sensor. The output of this first integrator is sampled after each lateral scan of the film, and the sampled output is transferred to a second accumulator or integrator arranged to store and aggregate information corresponding to a plurality of lateral scans of the film sheet. The output of the second integrator is in turn applied to a level detector and, when the output of the second integrator reaches a preselected level, the level detector transfers the accumulated information to a mechanical integrator for still further accumulation. The use of such a mechanical integrator relieves the need to hold large .amounts of information for long periods of time in an electronic integrator, and avoids the possible loss of information which may occur, due for example to leakage in the storage capacitor of such an electronic integrator, over a long period of time.

The incremental information transferred to the mechanical integrator is summed over a period of time; and when a preselected level of information has been accumulated in the mechanical integrator, a timer and replenishment solenoid valves are energized and cooperate to transfer replenishment chemicals from storage tanks to the processor tanks for a fixed interval of time and at-preselected flow rates. The flow rates may differ for the developer and fixer replenishment respectively. At the commencement of this fixed interval of time, the mechanical integrator is reset to zero preparatory to the accumulation of further information needed for a later replenishment operation.

The system of the present invention operates to cause chemical replenishment of the developer (and, if desired, fixer) during a fixed interval of time at a predetermined flow rate. The system actually operates to determine just when (in terms of integrated incremental image density) the said fixed time interval should commence. The system, moreover, postadjusts," i.e., replenishment occurs after a film sheet, or after a number of sheets, have been developed; and as a result, the replenishment actually takes into consideration the amounts of chemical depletion or degradation which have occurred as I a result of development and related activities over an extended period of time. I

The film reader, including the scanner and integrators to be described hereinafter, may take various forms. Moreover, while the film reader finds particular utility as a portion of an automatic replenishment system such as has been described, the reader itself may be employed in other environments, e.g., for purposes of merely examining sheets of film or other image-bearing materials by the transmission of light therethrough, or by reflection of light from a surface thereof. to determine the average density over the entire sheet. and/or the maximum density existing in the sheet, and/or the minimum density existing in the sheet. and/or the image characteristics at a particular portion of the sheet. Information of this type is valuable in various environments, e.g., when it may become necessary to reproduce the image under in vestigation; and therefore the reader of the present invention finds utility in environments other than the automatic replenishment control to be described.

BRIEF DESCRIPTION OF THE'DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring initially to FIG. 1, an automatic film processor incorporating the automatic replenishment control of the present invention may comprise a plurality of processor tanks comprising at least one developer tank 10, at least one fixer tank 11, and at least one wash tank 12. Exposed sensitized material to be developed is fed in sequence through the tanks l0, l1 and 12 along a path of the type generally designated 13 by means of an appropriate transport system diagrammatically illustrated by rollers 14. Squeegee rollers 15 are located downstream of the wash tank 12; and the developed film is caused to pass through said squeegee rollers for partial drying, whereafter the film{iS fed through a drier 16 for final drying and collection. Apparatus es of this general type are in themselves well known.

In accordance with the present invention, a sensor arrangement is provided, adapted to completely inspect each sheet of film throughout both its width and length, to determine the different optical or image densities developed in different areal portions of the film by the processor action, thereby to provide a measure of the amount of chemical which may have been used up in the course of the development process. The sensor arrangement may take various forms; and in the preferred embodiment shown in FIG. 1 comprises a light projecting element 17 coupled to a scannable light source 18, and cooperating with a light collecting element 19. As shown in FIG. 1 the light projecting element 17 is disposed above the path of travel of a sheet of developed film, whereas the light collecting element 19 is disposed below said path of travel, and light is projected through the developed film for monitoring purposes. The

sensor elements

17 and 19 are, moreover,

located between the pairs of squeegee rollers 15 at a position between the wash tank 12 and drier 16. This particular location of the sensor 17-19 is advantageous since the squeegee rollers act as a baffle to prevent light fogging of undeveloped film located upstream of the sensor. Moreover, the filmat this sensor location is already developed and relatively dry and; being transported under some tension, is somewhat constrained, thereby facilitating the making of relatively accurate measurements of the image densities in the film.

The light scanning source 18 may take various forms; and two such forms are shown in FIGS. 3 and 4 respectively. The rate of scanning is directly related to the transport speed of the film by coupling the light scanning source 18 to the film transport system. In FIG. 1, this synchronization between the light scanning rate and the film transport rate has been depicted by the diagrammatic connection 20 between the scanning source 18 and squeegee rollers 15, which are in turn driven synchronously with the remainder of the transport system.

As the developed film is fed past the

sensor elements

17, 19 said elements cooperate with source 18 to perform a 100 percent inspection of the film in both width and length. More particularly, the

elements

17 and 18 cooperate with one another, and with the synchronous drive from the transport system, to effect a plurality of optical scans across the width of the film for each linear inch of film travel. In one actual embodiment of the present invention, the rate of scanning is lO scans for each linear inch of film travel; but other rates of scanning could, of course, be employed. The amount of light which is intercepted by element 19 during each individual scan, and during the. several light scans, represents a measure of the aggregated incremental densities developed in the sheet of film; and this light is collected by element 19 and fed to a control circuit 21 (to be described hereinafter in reference to FIG. 2).

Circuit 21 continually monitors the image density of each sheet of film developed, and the aggregate density of a plurality of such sheets; and selectively operates a solenoid controlled valve 22 adapted to permit the feeding of replenishment chemical from a reservoir or tank 23 via a manual valve 24, flow meter 25, and line 26 to the developer tank. A similar arrangement may be provided to effect controlled replenishment of the fixer solution in tank 11, but this has not been shown in FIG. 1 to simplify the drawings. In actual practice, as will be described in greater detail subsequently, control circuit 21 includes a timer element adapted to open one or more valves such as valve 22 for a fixed interval of time once the circuit determines that replenishment is needed. Manual valve 24 is used during initial set up of the equipment, in cooperation with flow meter 25, to fix precisely the rate of flow out of tank 23 when valve 22 has been opened; and the several elements thus cooperate with one another to produce a highly accurate rate of flow for a precise period of time to developer tank when the sensor assembly and cooperating control circuit determine that replenishment should be effected. It will be appreciated that when replenishment of the fixer tank is effected, it may be accomplished at a different flow rate from that of the developer replenishment, but in a manner otherwise similar to that already described.

The scanner assembly employed comprises, in accordance with a preferred embodiment of the invention, a fiber optic line scanner arranged to integrate photoelectrically the different optical densities developed in different area] portions of each sheet of image bearing photosensitive material, so as to provide a signal useful in compensating for the resulting chemical depletion by means of an automatic replenishment system. The principle employed is to scan the full film width with a rectangle of light having dimensions roughly 2.5 by 0.1 inches, said scanning being effected at a pitch of 10 lines per inch of linear travel through the sensor. The image modulated light is then transmitted to a receiving photocell via a further fiber optics bundle 45 to provide signals which are used in the manner to be described for control purposes.

As shown in FIGS. 2 and 3, scanner element 17 may comprise a supporting block into which are plugged one end of a plurality (e.g., 10) of fiber optic bundles 30 formed of suitable glass or plastic material. The other end of each bundle 30 is plugged into a stationary light-tight lamp housing 31 provided, on its interior, with a concentric drumlike shutter member 32 provided with three

apertures

33a, 33b, and 33c spaced 120 from one another. A lamp 34 is disposed within drum 32, said lamp 34 being energized by a stable DC or high frequency AC source 35 to avoid light level fluctuations. Drum 32 is driven by means of a shaft 36 mounted in appropriate bearings 37 carried by housing 31; and shaft 36 is in turn coupled to an appropriate driving element 38, driven in 'synchronism with the processor transport system via an appropriate chain drive or timing belt 39.

The several light bundles 30 are plugged into housing 31 (see FIG. 2) over a 120 arc. Light emitted by lamp 34 and passing through one of the apertures such as 33a, impinges on each of the light bundles 30 in succession at the housing 31 end thereof as drum 32 rotates, whereby a beam of light scans across the ends of each fiber bundle. The 120 disposition of the

several apertures

33a, 33b, and 330 further assures that as soon as the light beam provided by one aperture leaves the last one of the group of bundles 30, a beam of light from the next aperture immediately commences a further scanning operation across said bundle ends. This accordingly assures that the several light bundles 30 are scanned repetitively and in sequence, with zero flyback time.

Shaft 36 of the scanning source further carries a disc 40 having three permanent magnets 41a, 41b, and 410 mounted thereon in spaced relation to one another. A pair of magnetic proximity reed switches SW1 and SW2 are mounted adjacent disc 40 for selective actuation by magnets 41a etc., during each line scanning operation. Each of the reed switches SW1 and SW2 is of the single-pole double-throw type, and each is biased to normally make with one contact, and to switch to the other contact momentarily when a permanent magnet mounted on disc 40 passes adjacent to said switch Thus, during the scanning operation effected by rotation of drum 32, each of the switches SW1 and SW2 is periodically operated. The function of these switches will become more readily apparent from the description of FIG. 2 to be given later.

The fibers in each individual bundle 30 are, within the body of sensor structure 17, fanned out to form a line. These individuals linearly arrayed groups of fibers are designated in FIG. 2 as 30a, 30b, 300, etc. In the particular arrangement shown in FIG. 2, it has been assumed that the incremental optical densities in a sheet of film 43 having a width of 24 inches are to be sensed; and ten fiber bundles 30 are accordingly provided, each of which contains a plurality of fibers which are individually fanned out into a linear fiber array 30a etc., having dimensions roughly 2.5 inches by 0.1 inches so as to cover the complete width of the assumed sheet of film. It will be appreciated, however, that different numbers of fiber bundles 30, and different numbers of fibers within each bundle 30a etc., may be employed to accomplish scanning of film sheets having different widths, without limitation as to the width of the sheet of film to be monitored, and the light scanning arrangement is nevertheless such that each increment in width of the film is scanned by light of the same intensity. This represents a significant improvement over other types of scanning arrangements which might be employed wherein light is, for example, projected as a moving beam across the film or other material to be scanned. Such projected light beams tend to exhibit intensity variations due to the differences in distance between the light source and the point of light impingement as the beam is scanned, particularly in the case of scanning over very wide film areas.

Due to the fanning out of the fibers in each bundle, as each bundle 30 is illuminated by light from lamp 34 this illumination is translated into a narrow rectangle of light directly above the sheet of film 43. As the several bundles 30 are scanned in sequence this rectangle of light progresses across the width of the film and, after illuminating the last film segment, immediately reverts to the first bundle for a further scanning operation. The light transmitted through the sheet of film 43 is collected by a further fiber optics arrangement comprising a supporting sensor structure 19 associated with a light collecting fiber optics bundle 45 having the individual equallength fibers thereof laid out along a line underlying the several segments 30a, 30b etc., in the light transmitting portion of the sensor. Thus the amount of .light which is transmitted to collecting bundle 45 during each scanning operation varies with the image density encountered by the scanning light source during each individual scan.

The light gathered by fiber optics bundle 45 from the underside of film sheet 43 is passed through said bundle 45 and projected onto a photocell 46, or onto any other appropriate light sensing element. Photocell 46 is coupled to a resistive network 47 associated with a potentiometer 48 adapted to balance out the steady state photocell current to zero whereby the signal at point 49 remains at zero until sensor light is attenuated by the passage of image bearing material past the sensor assembly 17,

19. In the alternative, potentiometer 48 may be so set as to continuously supply a small signal, under otherwise quiescent conditions, to compensate for the effects of developer oxidation taking place even in the absence of any film developing activity.

' If we now assume that a sheet of film 43 having a developed image therein is passing through the

sensor

17, 19, the sensor light will be attenuated, during each scan, by the developed image. The amount of attenuation will be dependent upon the various incremental optical image densities encountered during a given scan; and the aggregate attenuation will produce a signal of related magnitude at point 49. The signal at point 49 is supplied to a commercially available operational amplifier A1 which includes a storage capacitor selected from the bank of capacitors C by a switch 50. Each of the capacitors in the bank C is of different value; and switch 50 is coupled to the incremental speed control switch of the automatic processor transport system so that when the transport speed of the processor is changed, the value of the integrating capacitance selected for amplifier 0A1 is also changed proportionately. Amplifier 0A1 thus acts as a fast integrator, and the signal level at its output 51, corresponding to the net charge on the integrating capacitor (C at the end of a single scan line, is a function of the total image density seen by the sensor during that particular scan.

Just before the end of each scan, the rotating magnet and associated reed switch arrangement already described operates to switch the blade of SW2 momentarily into contact with terminal 52 so as to transfer the output of fast integrator 0A1 to a sampling capacitor 53. Immediately following this, at the end of each scan, the blade of switch SW1 is momentarily switched into contact with terminal 52a so as to discharge the integrating capacitor in the bank C thereby readying amplifier 0A1 for the next subsequent integration operation. Thus, the amplifier 0A1 and the various switches associated therewith cause each line of information to be sensed and then transferred as a separate entity to sampling capacitor 53.

The charge in capacitor 53 acts as an input to a second or slow integrator or accumulator comprising a commercially available operational amplifier 0A2. Amplifier 0A2 is connected as a bootstrap integrator, or staircase generator, having a storage capacitor C and the successive inputs to sampling capacitor 53 cause a negative-going staircase output voltage at output 54 of slow integrator 0A2. The magnitude of each step depends upon the signal transferred to capacitor 53. The negative-going output staircase of slow integrator 0A2 continues toincrease negatively with each successive increment of information from fast integrator 0A1 until the negative potential at output 54 reaches the triggering voltage of a voltage level detector employing a commercially available opera- "tional amplifier 0A3. In one embodiment of the invention,

slow integrator 0A2 may be required to describe something in the order of 40-negative-going steps before this triggering voltage is reached so that, in effect, slow integrator 0A2 acts to accumulate information corresponding to perhaps 40 or more lines of information detected by the scanner.

When the triggering voltage of level' detector 0A3 is reached, a relay coil 55 is energized so as to close contact sets 55a and 55b associated therewith. The closure of contact set 55a operates to discharge capacitor C associated with slow integrator 0A2 so as to restore the signal at output 54 to its datum level preparatory to the accumulation of further multiline information by 0A2. The closure of contact set 5511 completes a circuit from a capacitor 56*through a drive magnet 57 associated with a stepping switch or mechanical integrator 58 of the ratchet and pawl type. Capacitor 56 has a charge thereon as the result of its connection to a DC source 56a, whereby completion of the circuit mentioned causes drive magnet 57 to be pulsed, thereby stepping the movable switch arm 58a of mechanical integrator 58 from one to the next of a plurality of

mechanical contacts

58b, 58c etc. against the restraint of a return spring 59. The DC source and

capacitor arrangement

56, 56a is utilized to assure that drive magnet 57 is merely pulsed upon closure of contact set 55b. thereby preventing any damage to drive magnet 57 due to any sustained energization thereof.

It will be appreciated that the operation of contact set 55a, in removing the charge from capacitor C of slow integrator 0A2, simultaneously reduces the input to level detector 0A3 below its triggering voltage. As a result, the mechanical integrator 58 is caused to move through one mechanical step when the output of .slow integrator 0A2 reaches a level corresponding to a plurality of lines of information; and the system is then caused to assume a condition proper to the summing of a further plurality of lines of information.

Mechanical integrator 58 acts as an inexpensive, longterm memory; and each stepping of that mechanical integrator corresponds to the accumulation of information from a plurality of scan lines. While it is possible to accumulate large amounts of information in a capacitor such as C there is always the possibility that such a capacitor may leak over a long period of time whereby attempts to accumulate and store information in a capacitor for an extended period of time may result in some loss of information. By using the mechanical integrator 58, it is possible for the equipment to be turned off and later turned on without significant loss of information, and the possibility of error due to capacitor leakage is minimized.

A selected fixed contact 60 in mechanical integrator 58 is coupled to a further delay coil 61 so that when mechanical integrator 58 has been stepped through a desired number of increments, a circuit is completed through switch arm 58a of said mechanical integrator and contact 60 to relay coil 61 to cause said coil to be energized by a source 62. Energization of relay 61 closes contact sets 61a, 61b, and 61c thereof.

Closure of contact set 61a establishes a holding circuit for relay coil 61 via a normally closed switch 62 to assure that relay coil 61 remains energized so long as switch 62 is closed. Simultaneously, closure of contact set 611) completes a circuit from capacitor 63, which was previously charged from a source 64 (for reasons similar to those given with respect to

elements

56 and 56a) to cause a reset coil 65 associated with mechanical integrator 58 to be pulsed. Reset coil 65 releases the pawl in the ratchet and pawl mechanical integrator 58 so that spring 59 may operate to return the mechanical integrator to its zero or starting position preparatory to the accumulation of further increments of information. The closure of contact set 61c completes a circuit from AC source to a timer T and a solenoid 71 wired in parallel with one another.

Solenoid 71 operates to open the valve 22 (see FIG. 1) so as to cause replenishment fluid to fiow at a previously set rate to the developer tank. This flow continues so long as timer T remains energized. Timer'T is a commercially available unit and comprises a synchronous motor having a mechanical detent 72 which operates to open switch 62 after a precise time interval. Other forms of timer, including solid-state'timers,

may be employed. When the time interval established by timer T elapses, the normally closed timer switch 62 is opened, thereby deenergizing relay coil 61 by simultaneously breaking the holding circuit for said coil 61, and deenergizing timer T and solenoid 71. The entire system thus operates to transfer replenishment chemical to the developer (and, if desired, fixer) tank of the processor for an interval of time, and then operates to reset itself to an initial or datum condition preparatory to reception of the next replenishment control signal from mechanical integrator 58.

It will be noted that, by the arrangement described, replenishment always occurs during a fixed time interval and at a fixed flow rate. The system actually operates to determine just when, in terms of integrated image density, the said fixed time interval should commence. If a particular film sheet, or a relatively small number of successive sheets, being fed through the processor exhibits relatively highintegrated image density, replenishment may commence a relatively short time after the processing operation starts. On the other hand, if the sheets being fed through the processor exhibit relatively low integrated image density, commencement of the replenishment operation will be deferred correspondingly. In all cases, however, replenishment takes place when the accumulated or integrated image density of one or more sheets indicates that such replenishment is needed. It will be noted moreover that the system operates to post-adjust," i.e., replenishment occurs after a film sheet, or a number of sheets have been developed; and the replenishment is governed by the nature of the images in the sheets previously developed. This avoids difficulties which have been present in prior systems where attempts have been made to estimate the amount of replenishment which will be needed due to the processing of a sheet or sheets of material, prior to the time the sheet is actually developed by the processor.

The various operational amplifiers, the mechanical integrator, the timer arrangement, etc., of the apparatus shown in FIG. 2 are in themselves all conventional and commercially available; and various modifications can be made in the mechanical and electrical details of the circuit without departing from the concepts of the present invention. Moreover, while the fiber optics arrangement of the

sensor

17, 19 represent a preferred embodiment of the present invention, other types of scannable sensors can be employed if desired. One such alternative scanner is shown diagrammatically in FIG. 4.

In the arrangement of FIG. 4, the several linear arrays of light fibers 30a, 30b, etc., of the FIG. 2 arrangement are replaced by individual shaped lucite

light distributors

75, 76 etc., each of which may be supplied with light from an appropriate scanning source via

fiber bundles

77, 78, etc., or analogous such light transmitting means. The several

light distributors

75, 76, are each shaped to define a lower, elongated, relatively narrow light transmitting area corresponding in dimension to the fanned-out linear array of fibers already described in reference to FIG. 2; and the side of said light distributors are coated with reflective material as at 75a, 76a, etc. Such light distributors or light concentrators are in themselves known; and reference is made, for example, to Miller US. Pat. No. 3,256,385 for a discussion of such structures.

The pickup portion 19 of the sensor (FIG. 2) may be replaced by a lucite light collector 79 having

plural segments

79a, 79b, etc., associated respectively with the

light distributors

75, 76, etc. While the

light distributors

75, 76, etc., should be separated from one another to permit appropriate scanning of the light as light is transferred from one to the next of said distributors, the

several segments

79a, 79b, etc., can be interconnected to one another as shown in FIG. 4 since the essential purpose of the light collector 79 is to merely accumulate information from all of the light distributors and transfer such information to an appropriate detecting and integrating arrangement of the type described.

It should further be noted that while the several scanner arrangements described have been depicted as scanning at the input side, and merely collecting light at the downstream side of the scanner, it is entirely possible to provide a continuous line of light at the input side (e.g., from an appropriate elongated line source of light extending completely across the sheet of film) and to effect scanning at the output side of the scanner. Moreover the scanning, whether accomplished on the input or output side, can be effected by any of various scanning arrangements already known to those skilled in the art; and the scanner need not therefore take the particular form shown and described in reference to FIGS. 3A and 3B.

While I have thus described preferred embodiments of the present invention, many variations will be apparent to those skilled in the art, and certain of these variations have already been described. It must therefore be understood that the foregoing description is intended to be illustrative only and not limitative of my invention; and all such variations and modifications as are in accord with the principles described are meant to fall within the scope of the appended claims.

Iclaim:

1. A film processor replenishment system comprising a film processor, means for transporting a plurality of sheets of varying image density bearing material through said processor for development therein, the developed sheets having different image densities at different areal portions thereof, sensor means adjacent said processor for monitoring the incremental density throughout substantially the entire length and width of each of said plurality of sheets of image bearing material, accumulator means coupled to said sensor means for producing an information signal related to the aggregate incremental image density of each said sheet and to the aggregate image densities of a plurality of such varying image density sheets, a source of replenishment chemical for said film processor, and control means responsive to said information signal for selectively controlling the feeding of replenishment chemical from said source to said processor when said aggregate image density reaches a preselected value.

2. The system of claim 1 wherein said sensor means includes means for optically scanning substantially the entire area of each of said developed sheets at a scanning rate related to the speed of transport of said sheet through said processor.

3. The system of claim 1 wherein said control means includes a valve between said source and said processor, and timer means for selectively opening said valve for a predetermined time interval.

4. The system of claim 3 including flow control means for metering replenishment chemical from said source at a predetermined flow rate when said valve is open.

5. The system of claim 1 wherein said accumulator means is operative to produce a signal which changes in magnitude, and level detector means responsive to the magnitude of said signal.

6. The system of claim 1 wherein said processor includes a container having development chemical therein, said sensor being located at a position downstream of said development chemical container to monitor the image density in each of said sheets after said sheet has been developed.

7. The system of claim 1 wherein said processor includes a development tank, a fixer tank, a wash tank, and drier means, said processor including transport means for transporting each of said sheets through said tanks in succession and in the order named to said drier means, said sensor means being located adjacent the input end of said drier means.

8. A film processor replenishment system comprising a film processor having means for automatically transporting a plurality of sheets of image-bearing material through said processor for development therein, sensor means adjacent said processor for monitoring the image density throughout substantially the entire area of each of said plurality of sheets of image-bearing material, said sensor means including a fiber optics array extending transverse to the path of travel of each such sheet through said processor and further including means coupled to said array for optically scanning each of said sheets at a rate related to the speed of transport of said sheet through said processor, accumulator means coupled to said sensor means for producing an information signal related to the image density of each said sheet and to the aggregate densities of a plurality of such sheets, a source of replenishment chemical for said film processor, and control means responsive to said information signal for selectively controlling the feeding of replenishment chemical from said source to said processor.

9. The system of claim 8 wherein individual fibers in said array are distributed along a line extending transverse to the path of travel of each sheet through said processor.

10. The system of claim 8 wherein said sensor means includes light distributor means disposed adjacent the path of travel of said sheets through said processor, said fiber optics array comprising plural bundles of optical fibers connected respectively to spaced portions of said light distributor means.

11. A film processor replenishment system comprising a film processor, sensor means adjacent said processor for monitoring the image density throughout substantially the entire area of each of a plurality of sheets of image-bearing material, said sensor means including means for scanning each of said sheets along a plurality of linear scan paths, accumulator means coupled to said sensor means for producing an information signal related to the image density of each said sheet and to the aggregate densities of a plurality of such sheets, said accumulator means including first integrator means for storing a signal related to the aggregate image density monitored during each of said linear scans and further integrator means coupled to said first integrator means for storing a signal related to the aggregate image density monitored during a plurality of said linear scans, a source of replenishment chemical for said film processor, and control means responsive to said information signal for selectively controlling the feeding of replenishment chemical from said source to said processor.

13. The system of claim 11 wherein said further integrator means includes an electromechanical stepping switch.

14. The method of controlling chemical replenishment in a chemical containing automatic processor of image-bearing materials comprising the steps of passing sheets of varying image density bearing material through said processor for processing by chemicals in said processor, optically monitoring the varying density images in each of said sheets throughout substantially the entire Width and length of each sheet after each of said sheets has been processed by said chemicals, storing information related to the aggregate image density in said monitored sheets, and supplying a preselected quantity of a replenishment chemical to said processor when said aggregate image density reaches a predetermined value.

Claims

12. The system of claim 11 wherein said further integrator means includes a storage capacitor.