IL50568A - Jam detector for document handling apparatus - Google Patents

Description

JAM DETECTOR FOR. OCUMENT HANDLING. APPARATUS The present invention relates to electronic control means and more particularly to novel electronic control means for use with document handling equipment as described in our co-pending application No. 42699, for feeding, separating and stacking documents which electronic equipment monitors all phases of the physical operations to provide reliable and accurate feeding, counting and stacking and to prevent jamming.

BACKGROUND OF THE INVENTION Document handling devices are presently employed in a large number of different applications. Some examples of such document handlers are devices for counting checks, punch cards, food stamps, paper currency and bank coupons, to name just a few. The basic requirements of such devices are to provide reliable operation at relatively high operating speeds in the feeding, separating, endorsing and stacking of the documents being handled. Due to the high speed operation, it is also important 4so provide means for protecting against faulty operation since if a jam were to occur with the documents fed at reasonably high rates of speed, severe damage to the mechanism, as well as the sheets, may occur before corrective measures can be taken.

It is also well known that the document feeders providing such high speed operation generate an appreciable amount of dust which, together with other ambient conditions, serves to deteriorate the sensitivity and hence the capability of the sensing means to function properly.

BRIEF DESCRIPTION OF THE INVENTION AND OBJECTS The present invention is characterized by providing means for overcoming the aforementioned disadvantage through the use of a novel sensing means having a capability of automatically adjusting its sensitivity in accordance with changes in ambient conditions and responding to deviations from a predetermined level. A means anticipating a jam condition by automatically halting the document handling apparatus upon failure of the sensing means to sense a gap between adjacent documents within a predetermined upper time period.

It is therefore one object of the present invention to provide a novel control means for document handlers and the like capable of automatically adjusting its reading sensitivity in accordance with changes in any one of a variety of ambient conditions affecting the operation.

Another object of the present invention is to provide novel electronic control means for document-handling apparatus and the like to enhance the capability of such apparatus to perform operations such as reliable high speed counting, batching, statistical sampling and is capable of retaining an existing count and resuming counting even in the event of jams or temporary exhaustion of the supply of documents being counted.

These as well as other objects of the present invention will become apparent when reading the accompanying description and drawing in which : Figure 1 is a simplified elevational view of a document handling device for feeding, separating, counting and stacking paper documents and the like.

Figure 2 shows a plan view of the various feed elements of Figure 1.

Figure 3 is a schematic diagram of the compensating quantizing threshold device employed for counting documents separated by the document-handler of Figures 1 and 2.

Figures 4a-4f are schematic diagrams which form the control circuitry for the document-handling device of Figures 1 and 2.

Figures 5a-5c show waveforms useful in explaining the circuitry of Figures 3 and 4a-4f.

DETAILED DESCRIPTION OF THE FIGURES Figures 1 and 2 show, in simplified fashion a document-handling device which is described in greater detail in co-pending application Serial No. 41445, filed January 31, 1973 and assigned to the assignee of the present invention. The detailed structure of the document-handling device of the aforementbned U.S. application will be omitted herein for purposes of simplicity, it being understood that the Structure described therein is incorporated in the present application by reference thereto.

The document-handling device has the major functions of providing means for feeding sheets of varying thicknesses, sizes, finishes and the like and of accepting such dissimilar sheet sizes without first collating sheets into groups having similar dimensional and/or surface characteristics and includes means for separating and counting the sheets and stacking the sheets once separated* Turning notf to a description of the electronic control means for reliably and accurately operating the document-handling device, fig. 4a shows the jam-delay and am prevention delay circuits.

The jam-delay circuit 320 is comprised of diode CR2 and capacitor for developing a rectified and filtered D.C. level at their common terminal and receives the signal from NAND gate 318 for a purpose, which will be fully described hereinafter. A potential divider comprised of resistors Rg and R1Q applies a portion of this voltage to the base of transistor whose collector is connected to the D.C. source +V through resistor Rj^ and whose emitter is connected to ground. The collector is coupled to the input of inventer 321 whose output is coupled to the remaining input of NAND gate 313 described in our co-pending application No. 42699.

The jam prevention delay circuit 330 is similar in design to the jam delay circuit 320 and is comprised of diode CRj and capacitor Cr for rectifying and filetering the input applied thereto. Resistor R^ and R^ operate as a voltage divider coupling a portion of the output voltage appearing at the common terminal between diode CR^ and capacitor C,. to the base electrode of transistor Q2 whose emitter is connected to ground and whose collector is coupled to +V through resistor R, „ .

During the time when no counting is being performed a portion of the D.C. level is applied to the emiiter of transistor Ql causing to conduct. At this time the collector of Q.J will be low (substantially zero volts) causing the output of inverter 321 to go high, thereby placing a high level at one input of NAND gate 313. In the absence of any counting the output of comparator 304 of the gap detector is high placing a high level at the other input of NAND gate 313 of the said detector causing its output to go low, which condition is reversed by inverter 314 to apply a high input to one input of NOR gate 316 and NAND gate 315. The output of NOR gate 316 is low applying a low level to one input of NOR gate 317. This causes the output of NOR gate 317 to go high which level is applied to the remaining input of NOR gate 316 to cause its input to go low. The presence of high and low inputs to NAND gate 315 causes its out ut to go high to apply a high level signal to the remaining input or NOR gate 317. This condition is sustained due to the cross-coupling of NOR gates 316 and 317 to apply a low level input to one-shot multivabrator 319. Let is now be assumed that a document enters into the region between light source 65 and transistor 72 of the sensor. This causes a low input to be applied to lead 311, causing the output of gate 313 to go high. This condition is reversed by inverter 314 to apply a low level to one input of NOR gate 316. This causes its output to go high which, in turn, applies a high input level to NOR gate 317which causes the output of NOR gate 317 to go low. This low level is applied to the remaining input of NOR gate 316 causing its output to remain high. This high level signal is applied to input 319a of one-shot multivibrator 319 to cause an output pulse of a predetermined pulse width to be developed at output terminal 319b. Simultaneously therewith, a positive going pulse is developed at the remaining output of one-shot multivibrator 319c which is applied to a circuit comprised of transistors put Q3, and Zener diode CR4 for developing an out /at the collector electrode employed to advance an electromagnetic counter means (Fig. 4c) by one count.

As was described in our co-pending application No.42699 the output of comparator 3o /remails' ¾t low level for the duration of the passage of a document which is of the order of 50 milliseconds, after which time the level at lead 311 abruptly increases to +5 volts D.C., causing the output of gate 313 to go low and the output of inverter 314 to go high returning a high level to gates 316 and 315. The output of gate 315 thus goes low. However, the capacitance of capacitor Cg and the resistance value of resistor R^ are chosen to cause capacitor to discharge at a slow rate whereby the high level at the terminal of capacitor coupled to one input of NOR gate 317 is retained thus preventing the bistable circuit comprised of NOR gates 316 and 317 from changing state and thereby preventing an erroneous pulse from being applied to one-shot multivibrator 319 until capacitor has had sufficient time to discharge. The discharge rate of capacitor is appropriately adjusted so as to permit the capacitor to fully discharge during a 20 millisecond time duration which lies well within the normal time interval of a "gap" but is adjusted to prevent the capacitor from being discharged within shorter time intervals which would occur as a result of holes, tears, or other mutilations in the document passing between lamp 65 and detector (transistor 72).

When the output of NOR gate 316 goes high, gate 318 is caused to develop a low level output to permit capacitor C^in the jam-delay circuit 320 to begin discharging. The time interval during which capacitor will be fully discharged is of the order of 100 milliseconds which is greater than the time required for the passage of one sheet through the region between lamp 65 and transistor 72 so as to maintain a high level output at the remaining input of gate 318. Once an amount of time has elapsed which is greater than the time required for one document to pass through the sensing region without the detection of a "gap", the output of inverter 321 goes low to cause the input of gate 313 coupled thereto to go low and thereby prevent the count discriminating circuit 310 from generating any further count pulse.

Jam-prevention delay circuit 330 operates in a fashion such that its one input terminal is coupled to +5 volts while its remaining input terminal is coupled to the ottput of NOR gate 316. When the presence of a document is sensed the remaining input of NAND ate 318 oes hi h causin its out ut to o low enablin ca a does not go high during a time slightly greater in time duration than the time in-which the document should be presenj£^_. capacitor C5 will discharge causing the collector output of transistor Q2 to go high. This condition is inverted by inverter 323 and applied to one input of NOR gate 324 whose other input is derived from gate 354 of Figure 4d which functions to provide a low level signal at the input of NOR gate 324 to cause the output of NOR gate 324 to go high. This condition is inverted by inverter 325 to apply a low level signal to the input of NOR gate 380 shown in Figure 4e to cause the electromagnetic brake and cluth mechanisms to be operated in a manner such as to prevent any further sheets from being fed into the document handling device to prevent the occurrence of a serious. Jam in the mechanism, or alternatively to halt or slow down the document handling device diiting batching or statistical sampling operations.

Jam Delay Circuit 320 and Jam Prevention Delay Circuit 330 (see Figures 4 and 5)are prevented from being timed out so long as the time interval between the detection of "gaps" does not exceed the adjusted time outs for these circuits as described in our co-pending application No 42699 . In a case of time out of the Jam Delay Circuit 320 the output of inverter 321 goes low which condition is coupled to lead 430 of Figure 4c. In the normal operating condition switch arm 364 is coupled to lower stationary contact 364a which couples this condition to lead 369 to one input of NOR gate 376 of Figure 4e to set the bistable flip-flop comprised of NOR gates 375 and 376 to the off state causing the output of NOR gate 375 to go low which causes the output of AND gate 379 to go high. With the time Figure 4d) also goes high causing the output of NOR gate 381 to go low thereby rendering transistor Qy non-conductive to decouple power from the motor control device by opening contacts 402a and 402b. Also RUN FF (Figure 4e) is reset, counting is inhibited by gate 313 (Figure 4a) and JAM light 391 is lit.

Inverter 321 and Jgate 313 (Figure 4a), together with gates 314, 317 and 318 form a "latch" which maintains the jam level as the documents are being removed also prevent the document detector from producing spurious count pulses as it adjusts to the lower (shadowed) light level..

The jam protection devices anticipate potential jam conditions so as to protect the equipment from being damaged before a jamming conditions can reach serous proportions.

The jam delay circuit 320 of Figure 4a will time out after a time interval which is less than the normal time duration between the sensing of two "gaps" causing gate 313 (Figure 4a) from preventing further counts to be coupled into circuit 310. The output is also coupled to switch 364 at the operator's panel (Figure 4c) to provide a halt signal which is coupled . into NOR gate 376 (Figure 4e) and causes the bistable comprised of gates 375 and 376 to reverse state to energize the brake and clutch mechanisms through gates 380, 382 and transistors described in our co-pending application No, ^8*^9 a Q10-Q^ /Simultaneously therewith, the output of inverter 321 (Figure 4a) is coupled through inverter 372 and transistor Qq(Figure 4d) to lead 390 of Figure 4c to illuminate the jam lamp 391. The resetting of the bistable comprised of gates 375 and 376 also causes gate 379 (Figure 4e) to go high. When the other input is high which occurs when gate 407 (Figure 4d) has its input level from inverter 321 low, the output of NOR gate 381 goes low to decouple power from motor M by opening switch arms 402a and 402b through the deenergization of relay solenoid K^.

The jam prevention delay circuit 330 which has a slightly shorter time limit will time out causing transistor O^ to be rendered non-conductive. This high level is reversed through inverter 323 applying a low input to gate 324 causing its input to go high. This state is reversed by inverter 325 causing its input to go low. This condition is applied to one input of NOR gate 380 (Figure 4a) to operate the clutch and brake mechanism in the same manner as was previously described and thereby preventing a jam before its possible occurrence. The jam prevention delay circuit 330 has a shorter time out period than jam delay circuit 320 so as activate the clutch and brake mechanisms in anticipation of a The jam delay one step further in that it deener- gizes motor M which is caused to time out.

It can be seen from the foregoing description that the present invention provides novel control means for document handling devices and the like which are adapted for accepting sheets or other documents, preventing morethan one document from passing through the drive and stripper means and for providing a gap between the separated document for counting purposes wherein the control means provides the functions of counting small or large numbers of documents and provides means for protecting the equipment against damage due to delays by anticipating any potential delay and immediately deenergizing the document handling equipment and providing an alarm indication in the form of a lamp (and/or audible alarm if desired) to alert the operator to a possible jam condition.

The electronics of the control system is further adapted to provide count pulses by sensing the separation between documents before they pass through the stacker to automatically adjust for changes in ambient conditions which may effect the sensitivity of the detector and to prevent perforation or mutilations within the documents themselves from being erroneously interpreted as a "gap" between separated documents. The circuit 310 of Figure 4a is adapted so as to prevent such erroneous detections for mutilations or other perforations within the document passing between the lamp and light-sensitive transistor of openings as large as three-quarter inches measured in the direction of feed of the documents.

Although there has been described a proffered embodiment of this novel invention, many variations and modifications will now be apparent to those skilled in the art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only by the appending claims.

Claims (3)

WHAT IS CLAIMED IS:

1. Control means .for operating apparatus for counting and stacking documents comprising : first means for receiving a stack of documents; stacking means; second means for separating said stack of documents and advancing said separated documents, one at a time to said stacking means whereby a gap is provided between the trailing edge of each documents and the leading edge of the next document; said control means being characterized by sensing means for detecting the presence of each gap to generate counting pulses; means coupled to said sensing means for counting said documents; jam detector means coupled to said sensing meansi; for generating a first output level when the time interval between succeeding count pulses is greater than the time required for one document to pass said sensing means; gate means coupled to said jam detector means for preventing said sensing means from transferring count pulses to said counting means when said jam detection means generates said first output level.

2. The control means of claim 1 being further characterized by comprising second gate means coupled to said jam detection means for halting said second means upon the occurrence of said first output level.

3. The sensing means for detecting the presence of each gap to generate counting pulses as claimed in any of claims 1 or 2 being characterized by comprising timing means coupled between said detection means and said bistable means for preventing setting of said bistable means when said bistable means has not been reset within