JP2540371B2 - Paper movement monitor - Google Patents

Description

The present application relates to a device for monitoring paper movement in a printing device. In particular, it relates to the use of printing presses for printing with continuous webs.

Continuous webs are generally provided to the press in the form of paper rolls. Paper roll printing machines are used in many applications. In financial accounting devices such as automated teller machines and check sorters, covert printers are provided to keep a visual record of transactions made or recorded. Concealed printers are also found in cash registers, electronic analyzers, small electronic graph plotters, chart recorders and the like. The present invention is particularly directed to detecting paper movement problems in covert printers where there is no operator oversight.

A common function of printing machines is to cause the printing device to cross a line of printing. The web is then advanced by one or more line spacing distances and the printhead again prints one line. In the past, monitors have indicated when the paper will line feed depending on electrical signals between the printer and the monitor itself. The present invention seeks to improve this situation by allowing the monitor to rely on its function only by moving the paper, and not on any ancillary points to the operation of the printer. The present invention thus seeks to achieve true additional performance for such monitors regardless of the type of printer used.

The invention resides in an apparatus for monitoring paper movement in a printer, the apparatus including a first movement sensor,
Point to engage the paper with the printer and to detect the distance traveled by the paper at the first point during the printing of successive lines, detected by the first sensor. If the distance traveled is not within the first and second predetermined limits, the device provides an indication of a paper feed error.

One preferred embodiment of the present invention provides roll means rolling against the paper and rotation detection means for detecting rotation of the roll means. The paper movement error is not flagged or displayed unless the roll means has rotated at least a predetermined distance and greater than another predetermined distance for a first time period after detection of the first movement. If the movements detected during the movement period are too short or too long,
An appropriate error is displayed. If any paper movement is detected during the second period during which printing should occur, the pseudo paper movement is displayed.

Printers typically have paper input points and paper output points. If any misbehavior occurs in the printer causing paper tears or paper stacks, simple prior art paper movement monitors will not detect this condition. A second aspect of the present invention is operative to engage the paper at the second point with the printer and to detect the distance traveled by the paper at the second point during printing of successive rows. Seeking to provide additional use by including a movement sensor in the device, the device operating to perform a first sum of the distances detected by the first sensor, and detected by the second sensor. A second sum of distances is made, and an indication of paper deposition is provided when the difference between the first and second sums exceeds a predetermined amount.

When using a set of devices that rolls against paper, it is not possible to find two roll devices that have the same manufacturing tolerances and therefore the same sensitivity to paper movement when their respective rotations are summed. The problem is ensuring that it is virtually impossible. Accordingly, the present invention includes first roll means for the first sensor to roll on the feed sheet, and first rotation detection means for providing an output indicative of angular movement of the first roll means, and a second sensor. Includes a second roll means for rolling the paper and a second rotation detecting means for providing an output indicating the angular movement of the second roll means, and the sum of the outputs of the first rotation detecting means is obtained. The device self-calibrates by summing the outputs of the two rotation detection means and finding the ratio between the sums of the outputs of the first and second rotation detection means to establish the feed ratio. The present invention multiplies the sum of the outputs of the first or second rotation detecting means by the feed ratio to normalize the outputs of the first and second rotation detecting means and have the same sensitivity to paper movement. To do so.

The present invention further forms a long-term value of the feed ratio based on the paper movement according to the first number of print lines, and a short-term value of the feed ratio based on the paper movement according to the second number of print lines less than the first print line number. And the ratio between the long-term value of the feed ratio and the short-term value of the feed ratio is outside the predetermined upper and lower values, the first
And there is an indication between the second sensor that there is a paper movement problem. The present invention further provides the establishment of long term and short term values of the feed ratio in the first calibration routine.

In one form of the movement sensor of the present invention, one or only wheel rolls against the paper and a rotation detector is coupled to monitor the rotation of the sole wheel.
The preferred form of rotation detector is a circular grating of optical light transmission, which provides a plurality of countable pulses for each row sent by the printer.

In a second preferred form of the paper movement sensor of the present invention, the first
Given in the form of an edge wheel and a second edge wheel of
Each is provided to rotate with respect to a portion of the feed sheet near its respective edge. Each edge wheel is provided with a respective edge wheel rotation detector. In either case, the preferred form of edge wheel rotation detector is the same general type of optical diffraction grating used in single or sole wheels.

In addition to detecting paper feed errors in the printer, the present invention also detects distortion errors in which one side of the paper is jammed and the paper rotates using another angle from its feed direction. Thus, the present invention provides an indication of paper skew at the printer input or at the printer output when the sum of the edge wheel rotation detector outputs exceeds a predetermined limit. In order to minimize the effect of the diameter tolerance of the two edge wheels of the sensor,
The invention provides a ratio between the first one output of the edge wheel rotation detector and the second one output of the edge wheel rotation detector to provide the edge ratio. To be done. The edge ratio is then used to multiply one or the other output of the edge wheel rotation detector to normalize the sensitivity of the edge wheel rotation detector to the same for equal feed of paper. To be there. The invention further provides that the long-term value of the edge ratio is formed based on the paper movement of the first number of print lines, and the short-term value of the edge ratio is less than the first number of print lines. Formed based on movement, a paper skew is displayed when the ratio between the long-term edge ratio value and the short-term edge ratio value is outside the predetermined upper and lower values. In this way, the formation of long-term and short-term values of the measured parameter or ratio, where long-term slight paper movements that are likely to cause errors are detected and long-term or short-term values are formed,
It provides the function of self-calibration, which allows for long-term wear and short-term perturbations in mechanical parameters.

Like the feed ratio, the initial values of the long and short edge ratios are established during the calibration routine.
In the present invention in which two sensors are employed, there is of course a first edge ratio for the first sensor and a second edge ratio for the second sensor, both treated as explained above.

The invention further relies on the printer inlet or printer outlet depending on where the inconsistency was found when the ratio between the long-term paper feed value and the short-term paper feed value was outside a predetermined limit. Either can flag a paper movement error. Similarly, the present invention forms a ratio between the long-term value of the output of each edge wheel rotation detector and the short-term value of each edge wheel rotation detector, the ratio thus formed being within a predetermined range of values. Try to give a distortion error when out of.

Where a set of edge wheels is used, the amount of paper feed is taken as the average of the individual normalized or unnormalized edge wheel rotation detector outputs (ie half the sum of the outputs). In sole wheel sensors, the wheel is mounted in the middle of the paper so that it is insensitive to strain. By taking the average value of the edge wheel rotation detector output, an equivalent centering of the sole wheel is achieved as far as the output is sensitive and insensitive to strain.

The paper movement sensor is in each case provided on a housing containing a set of arms. The arm engages some part of the device associated with the printer. Second of the second paper movement sensor
Of the housing has an arm that engages the housing of the first paper movement sensor. In this way both paper movement sensors can be hinged independently of the printing device for paper loading. Preferably, the housing of the first paper movement sensor is the same as the housing of the second paper movement sensor for manufacturing economy. In more complex printers, as many paper movement sensors as needed can be stringed together to monitor paper movement at an increased number of points.

The present invention is further described, by way of example, by the following description taken in conjunction with the accompanying figures.

 FIG. 1 shows the overall system in which the present invention is employed.

FIG. 2 shows a cross-sectional view of a printer suitable for use with the present invention and also shows the location of the paper movement sensor.

FIG. 3 shows a cross-sectional view of a paper movement sensor employing a single wheel.

FIG. 4 shows a perspective view representation of the single wheel paper motion detector of FIG.

FIG. 5 shows a schematic diagram of a photoelectric rotation detector suitable for use in connection with the wheel rotation detector diffraction grating of FIG.

FIG. 6 is a flow chart showing the first level operation of the monitor logic of FIG. 1, in which a gross and near-instantaneous paper movement error is detected.

FIG. 7 shows a cross-sectional view of a paper movement sensor that employs a set of edge wheels.

FIG. 8 is a flow chart showing the initial calibration routine, which is used to establish long-term and short-term values of different ratios and parameters, and is particularly directed to the situation where the sensor shown in FIG. 7 is employed.

FIG. 9 shows how the monitor logic of FIG. 1 performs a continuous self-calibration function and how to detect long-term paper movement errors.

FIG. 1 shows a schematic diagram of the whole system in which the present invention is adopted.

The paper roll 10 feeds the continuous web 12 to the printer as indicated by the first arrow 14. The first movement sensor 18 is the paper 12
Monitor the movement of the paper as it enters printer 16. Printer
The 16 is controlled by a printer control processor 22 via a two-way printer connection 20, which causes the printer 16 to feed the paper 12 and print a visible record thereon in response to external commands and data.

Upon receipt of the printed record, the paper 12 exits the printer 16 as indicated by the second arrow 24. Second paper movement sensor
26 monitors the movement of the paper 12 exiting the printer 16.

First paper movement sensor 18 and second paper movement sensor 26 provide inputs to monitor logic 28 responsive to inputs of paper movement sensors 18, 26 in a manner described below. Monitor logic 28
Is to analyze the outputs of the paper movement sensors 18, 26 and use the analyzed inputs to detect paper movement errors. When a paper movement error is detected, monitor logic 28 provides an indication on error display 30 and an output on inhibit line 32 to cause printer control processor 22 to correct or cease its printing operation.

The present invention relates to a first paper movement sensor 18 and a second paper movement sensor.
Involves monitor logic 28 with 26.

FIG. 2 is a cross-sectional view of an exemplary printer that can be used with the present invention. It is understood that the type of printer shown in FIG. 2 is not limited in type as far as the invention is concerned. The printer of FIG. 2 is shown as an example only. FIG. 2 also shows the positions of the first paper movement sensor 18 and the second paper movement sensor 26.

Paper 12 is fed from roll 10 onto input platform 34 by a set of opposed pinch wheels 38 which grip paper 12 into print well 36, one of which is driven to feed paper 12. Paper 12 passes from pinch wheel 38 to the surface of stationary platen 40. A dot matrix type printhead 42 is supported by a set of rods 44, generally at 90 ° to the plane of the paper, as shown in FIG. 2, along rods 44 and here and there to platen 40. Moving paper
Print over 12. Once printed, the paper is moved by a pinch wheel 38 to an exit platform 46 where it is passed to an additional roll for storage or to an exit slot (neither shown) for retention by the user. Passed.

The first paper movement sensor 18 uses the input platform 34 to feed the paper 12
To trap the paper 12 between itself and the input platform 34. The paper 12 slides freely against the input platform 34. The second paper movement sensor 26 similarly engages the paper 12 at the exit platform 46.

The entire printer 16 is powered by a motor 48 which operates to rotate the cam disk 50 once for each print line. The cam disk 50 includes a magnet 52 which is detected by the magnetic sensor 54 at a predetermined position. When the magnet 52 is again detected by the magnetic sensor 54, a signal is passed to the printer control processor 22 to remove power from the motor 48. During the rotation of the cam disc 50, the cam rider 56
Of the paper and platen which are moved up and down on the contoured lower surface of the paper and fed by the facing pinch wheels 38.
Control movement of printhead 42 across 40. The rotation of the cam wheel 50 causes a first movement in which the paper 12 is fed in line intervals and a second movement in which the head 42 crosses the platen 40. While the head 42 is traversing the platen 40, the printer control processor 22 provides control signals to the dot matrix print head 42 so that the desired visible record is left on the paper 12.

As mentioned above, the style of printer shown in FIG. 2 is not limiting with respect to the present invention. The present invention detects errors in the paper passing through the input platform 34, in the paper passing through the exit platform 46, and errors where the paper 12 deposits in the print well 36 or is broken in passing through the print well 36. Ask for.

FIG. 3 is a movement sensor also shown in FIGS. 1 and 2.
27 is a cross-sectional view of one of the preferred shapes of 18,26.

The sensor housing 58 includes shaft openings 60 at both ends thereof,
There, the shaft 62 is supported by the bush 64 at its extreme end. The sole wheel 66 is provided in the center of the shaft 62 concentrically fixed thereto. The sensor housing 58 is generally closed and the sole wheel 66 projects through the wheel opening 70 to the lower surface 68 of the housing 58. The wheel 66 has a sufficient clearance from the lower surface 68 of the sensor housing 58 so that the wheel 66 can freely roll with respect to the paper 12. The sensor housing 58 is fixed with respect to the moving paper so that the shaft 62 is at the correct angle with respect to the desired direction of movement of the paper 12.

The inner wall 72 of the housing 58 through which the shaft 62 passes is the sole wheel
66 is separated from the dust protection chamber 74, in which there is an optical diffraction grating 76 which is concentrically fixed to the shaft 62 and is free to rotate in the dust protection chamber 74. When the paper 12 rotates the sole wheel 66, the optical diffraction grating wheel 76 rotates the same amount.

FIG. 4 shows a projection view of the paper movement sensors 18, 26 of FIG. In FIG. 4, the housing 58 is shown in phantom outline for clarity, as if it were made of a transparent material. The housing 58 can of course be made of a transparent material, but it is understood that it can equally be made of an opaque material without loss of functionality.

The shaft 62 is retained in the end slot 78 of the end wall of the housing 58 by a leaf spring 80 and is positioned against the surface of paper 12
Allowing movement in 58 degrees of freedom, the paper 12 adapts vertical tolerances (as shown in FIG. 2) without imparting undue friction to either the input platform 34 or the exit platform 46. be able to. The housing 58 includes a set of support arms 82 and has a ledge 84 at its distal end to engage a support 88 (generally shown in phantom in FIG. 2) or It operates to engage a hole or recess 86 in another housing 58. Thus the second
The first sensor 18 in the figure engages the support means 88 and the second paper movement sensor 28 in FIG. 2 engages the housing of the first paper movement sensor 18. If additional paper movement sensors along the exit path of the paper 12 are required, they can be mounted in long chains as shown in FIG.

Returning to FIG. 4, the photodetector yoke 90 covers the optical diffraction grating wheel 76 provided with the opaque area and the transparent area for light which are circumferentially equally spaced. The photodetector yoke 90 shines light on the optical diffraction grating wheel 76 to detect passage and non-passage thereof, and the wheel 66
Generates a pulsed electrical signal that changes as the paper rotates, each pulse representing a predetermined distance of movement of the paper 12 under the wheel 66.

FIG. 5 is a schematic diagram of the electrical circuitry associated with the optical grating wheel 76. Photodetector yoke 90 includes a light emitting diode 92 or other light source that illuminates light to optical grating wheel 76. Light passing through the optical grating wheel 76 is received by the phototransistor 94. First
The resistor 96 regulates the electrical current from the power rail 98 through the light emitting diode 92 whose other terminal is connected to the ground rail 100. The emitter 102 of the phototransistor 94 is also connected to the ground rail 100. The second resistor 104 loads the collector 106 of the phototransistor 94 to develop a voltage responsive to the amount of light incident on the phototransistor 94.
The collector 106 of the phototransistor 94 is connected to the first input terminal of the voltage comparator 108, and the second input terminal of the voltage comparator 108 is connected to the reference voltage source 110. When the voltage at the collector 106 of the phototransistor 94 exceeds the value of the reference voltage source 110, the output 112 of the comparator 108 provides a logic signal of the first polarity and the voltage at the collector 106 of the phototransistor 94 is at the reference voltage source 110. If less than the value, output 112 of comparator 108
Gives a logic signal of opposite polarity. As wheel 66 rotates, comparator 108 provides as output 112 a series of alternating polarity logic pulses. Phototransistor 94 and light emitting diode 92 are typically included in photodetector yoke 90. Resistors 96, 104 and sources 98, 110, 100 of comparator 108 are also typically provided by monitor logic 28. Connecting wire 114 connects photodetector yoke 90 to monitor logic 28.

The electrical circuit shown in FIG. 5 is given as an example only. It will be appreciated that many other forms of electrical circuitry could equally well be used by the photodetector yoke 90 and monitor logic 28, and different forms of each circuitry would be equally applicable in the present invention. The output need only be provided to respond to the rotation of the sole wheel 66. As with other optical circuit detectors known in the art, the present invention provides that a tachometer integrated with a magnetic rotation sensor is used to detect the rotation of sole wheel 66.
Those skilled in the art are aware of other means by which the rotation of the sole wheel 66 can be detected, and each of the other means is applicable to the present invention.

FIG. 6 is a flow chart of the operation of the monitor logic 28 for detecting an instantaneous paper movement problem using the information available from the paper movement sensors 18, 26 shown in FIGS. 3, 4 and 5.

When the monitor logic 28 operates, the sixth command is issued via the start instruction 116.
Enter the routine shown in the figure. Logic output 112 of comparator 108
A first test 118 is performed to see if the has changed. If no change has occurred, the first test 118 is repeated until a change is detected at logic output 112. When a change is detected in the logic output 112 of the comparator 108, the first test moves to a first operation 120 where the execution count N of the number of changes to the output 112 of the comparator 108 is a value of one. Is set. At the same time, the first timer T1 starts its operation. Then the first operation 120 controls the second test 1
Pass 22 to look for changes in logic output 112 of comparator 108. If no change is perceived, the second test 122 passes control to the third test 124 to test to see if the period of the first timer T1 has expired. If the period of the first timer T1 has not expired, the control is the second test.
Returned to 122. When the second test 122 perceives a change in the logic output 112 of the comparator 108, control is passed to a second operation 126 to increment the running count N of pulses from the logic output 112 of the comparator 108 by one. . The second operation 126 then passes control to a fourth test 128, which tests to see if the period of the first timer T1 has expired. First timer T1
At the end of the period, control passes to the fifth test 130. If the period of the first timer T1 has not expired, control is returned to the second test 122 to determine the logical output 11 of the comparator 108.
Look for further changes in 2. If, while waiting for a change in the logic output 112, the third test 124 detects that the period of the first timer T1 has expired, control passes directly to the fifth test.
Passed to 130.

The duration of the first timer T1 is selected to be slightly longer than the time required for the cam disk 50 to move the cam follower 56 to cause the pinch wheel 38 to move the paper 12 line by line. It In this example, an optical grating wheel
The frequency number of the 76 alternating light or dark patterns is at least 3 by the output 112 of the comparator 108 during paper movement,
It is also selected so that no more than 5 pulses are applied.
The line feed target value is actually selected as 4 pulses in this example. In fact, the first pulse may have just been given during the previous leading and is therefore omitted. Alternatively, the additional pulse may have just occurred at the end of a line feed due to the lack of phase integration between the pulse and line feed. Thus, a target value of 4 may lack one pulse and may acquire additional pulses. Effective leading is therefore taken as a number of pulses one more or one less than the target value.

The fifth test 130 is that the execution count N between line feeds is 3
Test to see less than pulses. If the execution count is less than 3 pulses, the "clog" routine
Exiting via 132, the paper 12 moves less than the desired pulse value during line feed, commanding appropriate action from the error display 30 and printer control processor 22. Fifth
Test 130 of the comparator 108 indicates that more than two pulses have been detected at the output 112 of the comparator 108, control is passed to the sixth test 134 to determine if more than five pulses were obtained in the run count. To test. If an execution count of more than 5 pulses is obtained, the control is "overrun".
It is passed to routine 136 and is given an indication that some cause caused it to feed more paper than expected during the line feed. This occurs when another device or person pulls the paper 12 or the paper is wrapped around either pinch wheel 38. The "overrun" routine 136 prompts the appropriate response from the error display 30 to provide the printer control processor 22 with the appropriate input.

If the sixth test 134 detects that 5 or less pulses have been obtained in the execution count N, then control passes to the third.
Operation 138, where a signal is passed, if desired, to printer control processor 22 to obtain the correct "feed" and start a second timer T2.

The duration of the second timer T2 is slightly longer than the time required for the printhead 42 to traverse the platen 40 to print a line of print. It is important that no paper is sent during this period. Therefore, the third operation 138 sends control to the seventh test 140 to look for changes in the output 112 of the comparator 108. If no change is detected instantly, the seventh test
140 is repeated. If a change is detected by the seventh test, control is passed to the eighth test 142 to see if the second timer T2 period has expired. If the second timer T2 period has not expired, the routine exits via the "pseudo feed" routine, but informs the error display 30 and printer control processor 22 that the pseudo feed was performed while printing was performed. Show. The eighth test 142 is the second timer T
Upon indicating that the second period has expired, control is returned directly to the first operation 120. Ninth test 144 is seventh test 140
If the seventh test 140 does not detect any change before the second timer T2 period expires, the control is
To pass directly to test 118.

The routine shown in FIG. 6 corresponds to the first paper movement sensor 18 provided independently, and in the system in which both are provided, the first paper movement sensor 18 and the second paper movement sensor 28. It is understood that it is performed for both. Further, it is also understood that the count N in FIG. 6, shown here as the raw number of changes in the output 112 of the comparator 108, can be a modified or normalized count by the method described below. It Second operation for those skilled in the art
It can be seen how 126 causes the execution count N to be a normalized value rather than the sum of the raw counts. This is obtained by multiplying the actual count sum by the correction factor whose extraction is described below.

With respect to FIG. 6, if the printer 16 is stopped for any reason, or the paper 12 is changed, or cleared of jammed or torn paper, it is desired to restart the printer. Therefore, when the reset button (not shown) is pressed, the reset operation 146 will cause the first operation 1
Make a direct entry into the 20.

When both the first paper movement sensor 18 and the second paper movement sensor 26 are present, the monitor logic 28 causes the print well of the printer 16 to print.
Gives detection of short-term movement errors within 36. When the first paper movement sensor 18 gives a normal count and the second paper movement sensor 26 gives a low count, the paper is in the print well 36.
Is deposited in. It not only jams the paper (from either paper movement sensor 18 or 26), but also paper 12
You will also be given a display that shows where is stuck. If the second paper movement sensor 26 showed a normal count, the first paper movement sensor 18 showed a low count, and until then there was no indication of error, then the paper 12 was broken in the print well 36. Is shown. In other words, the first paper movement sensor
The difference in the counts obtained by 18 and the second paper movement sensor 26 provides a clear indication of anomalous paper movement in the print well 36. In particular, the monitor logic of the present invention
28 is operable to maintain a running count of several rows for each of the first paper movement sensor 18 and the second paper movement sensor 26, the difference in execution counts exceeding a predetermined limit. And flag an appropriate error indication of anomalous movement of the paper in print well 36. Not shown in FIG. 6, but within the scope of the present invention, is the operation of monitor logic 28 when no count is obtained from either first paper movement sensor 18 or second paper movement sensor 26. Is. When a zero count is obtained from both sensors 18, 26 together, the monitor logic 28 indicates either a lack of paper 12 or a general jam. If only the first paper movement sensor 18 indicates a zero movement, the monitor logic 28 will display an error display 30 and printer control processor indicating a paper break in the print well 36 or the roll 10 of paper 12 has run out. Give to 22. A simple out-of-paper indication is provided when the monitor logic 28 detects a count of 0 from the first paper travel row 18 shortly after the lower count from the first paper travel sensor 18. 0 count is the second paper movement sensor
Obtained from 26 alone, monitor logic 28 outputs an indication of a paper break in either print well 36 or platen 40 to error display 30 and printer control processor 22.

The invention thus far described relates to the detection of short term detectable or instantaneous errors in the paper feed of printer 16.
The present invention addresses detection of strain conditions where the path of the paper 12 is twisted or altered.

FIG. 7 shows a sensor 18, according to a second preferred embodiment,
FIG. 26 is a sectional view of 26.

The housing 148 exhibits the same general outer profile as the housing of FIG. 4, but the shaft 62 of FIG. 4 is a set of aligned half shafts 15.
Replaced by 0, each extending less than half way through the second housing 148 and supported by bushings in openings in the outer wall 154 and inner support wall 156 of the second housing 148. The edge wheel 158 rolls against the paper 12 by projecting from the respective bottom surface 160 of the second housing 148. The dividing wall 162 separates the edge wheel 158 from the optical wheels 164 each present in the dust protected chamber 166, which is at either end of the second housing 148. Each edge wheel 1
The 58 are capable of independent free rotation with respect to each other. Each optical wheel 164 is provided with a photodetector yoke 90 and the circuitry shown in FIG. 5 to allow interfacing to monitor logic 28.

With respect to FIG. 7, monitor logic 28 performs an additional function to detect paper skew. Incorrect count on either edge wheel 158 as paper 12 moves (in this case preferably less than 3 or more than 5 pulses)
When issued, the monitor logic 28 indicates that the paper is distorted in the direction of the way it leans toward the side with one particular edge wheel 158 causing the lower count.
And to the printer control processor 22. Similarly, like the single or only wheel 66, the monitor logic 28 operates to maintain a running sum of the counts obtained from each edge wheel optical wheel 164. If the running sums show a difference in a predetermined number of rows having a magnitude greater than a predetermined limit, then an indication of distortion in the direction of lesser counts is provided to error display 30 and printer control processor 22.

The sole wheel paper movement sensor shown in FIG. 3 can be replaced in either or both positions shown in FIG. 2 by the two edge wheel paper movement sensor shown in FIG. Sole wheel 66, paper movement sensor
With 18, 26 thus replaced, the monitor logic 28 draws the undistorted output from the sole wheel 66 (at the center of the paper) from the two edge wheel optical wheels 164 with the equivalent advantage (ie, Must be replaced with the display (no distortion). To do this, monitor logic 28 performs the following calculations: Let e1 = instantaneous count of left edge wheel 158 at first sensor 18: e2 = instantaneous count of right edge wheel 158 at first sensor 18 and Let: e3 = instantaneous count of the left edge wheel 158 at the second sensor 26: e4 = instant count of the right edge wheel 158 at the second sensor 26: a1 = paper found by the first sensor 18 Let it be the instantaneous count of the feed: a2 = the instantaneous count of the paper feed found by the second sensor 26: where "instantaneous" means "for each line of the paper feed" and is as follows: and It is understood here that the e and a values can be normalized as described above and below.

The instantaneous line feed count found in the above calculations is used in the routine of FIG. 6 and in all routines described in connection with the operation of FIG. 6 and monitor logic 28, otherwise the sole wheel. Used as a count of 66. Since the edge wheel 158 is positioned symmetrically with respect to the edge of the paper 12, the drawn counts a1 and / or a2 show no distortion. The symmetry of the edge wheel 158 ensures that the sum that remains constant as distortion that increases the count of one edge wheel 158 decreases the count of its co-edge wheel 158.

FIG. 8 shows a flow chart of the manner in which the apparatus of the present invention self-calibrates to accurately accommodate the detection of long term paper feed errors. The routine shown in FIG. 8 allows the difference in diameter between the wheels 66, 158 to be accommodated as well as the difference in the number of pulses per rotation angle from the optical grating wheel 76 and the optical wheel 164. Forgive

The start command 168 is issued when a new paper 12 is loaded or when it is desired to test or recalibrate the system. The start command 168 can be issued from the printer control processor 22 or initiated by a push button switch used by the operator.

The start command 168 immediately passes control to the fourth action 170,
The printer control processor is commanded to cause the paper 12 to advance a predetermined number of lines. In this example, the number of selected rows is
Twenty. A larger number of rows is selected for greater precision, and a smaller number of rows is selected if less precision is acceptable. The number selected here is one example.

The routine shown in FIG. 8 shows a state in which the first paper movement sensor 18 and the second paper movement sensor 26 are of the type shown in FIG. The routine in FIG. 8 is processed by the cumulative sum of the pulses from the four edge wheels 158. If one or the other of the paper movement sensors 18, 26 is of the type shown in FIG. 3, the edge wheel pull out pulse count routine is omitted for all sensors of the type shown in FIG. It is understood that in the calculation the average feed of the sole wheel 66 is used instead.

The fourth operation 170 spans a chain of two simultaneously performed operations. The pulses derived from the optical wheels 164 associated with the individual edge wheels 158 of the first paper movement sensor 18 in the first chain are counted in a fifth operation 172. The fifth operation 172 extends to the sixth operation 174, and the edge ratio of the first paper movement sensor 18 is the cumulative count drawn from the left-hand optical wheel 164 and the right-hand optical wheel 164. Calculated by taking the ratio between. The sixth operation 174 passes control to the seventh operation 176, and the average feed of the first paper movement sensor 18 is calculated.

At the same time that control is passed to the fifth action 172, the second chain action that calculates the edge ratio and average feed of the second paper movement sensor 26 is the eighth action corresponding to the fifth action 172. Action 178
Then, a ninth operation 180 corresponding to the sixth operation 174 and a tenth operation 182 corresponding to the seventh operation 176 are achieved. Thus, the edge ratio and feed are calculated for the first paper movement sensor 18 and the second paper movement sensor 26 over many print feed lines.

Finally, the results of the tenth operation 182 and the seventh operation 176 are the eleventh.
The two paper movement sensors 18, 2 combined in operation 184 of
A feed ratio of 6 is calculated. The exact algebraic relations in the variables are explained below. Upon completion of the eleventh operation 184, the routine of FIG. 8 goes to further operations via the exit routine 186.

 The calculation is done as follows: Send M lines of paper.

E1 = cumulative count from the left edge wheel 158 of the first sensor 18: E2 = cumulative count from the right edge wheel 158 of the first sensor 18: E3 = left edge wheel 158 of the second sensor 26 Let E4 be the cumulative count from the right edge wheel 158 of the second sensor 26: E4 = Calculate the edge ratio of the first sensor 18 (ER1): Calculation of the edge ratio of the second sensor 26 (ER2): Calculation of cumulative feed of the first sensor 18 (A1): Calculation of cumulative feed of the second sensor 26 (A2): Overall system feed ratio calculation (AR): The edge ratios ER1 and ER2 are the seventh in the embodiment of the movement sensors 18 and 26.
Reflects the ratio of counts drawn from the edge wheels in the figure. The edge ratio is used to correct count errors induced by different spacing rates in the dark and light areas of the optical wheel 164 and different diameters of the edge wheel 158. The calculations performed by the monitor logic 28 are as follows: E2 corrected value = E2.ER1 = E1 E4 corrected value = E4.ER2 = E3 Similarly, the feed ratio AR can detect differences in later feeds. As such, it is used to correct differences in average feed counts and errors.

It should be remembered that the corrected value of A2 = A2.AR = A1 The corrected value of E2 and E4 is equal to E1 and E3 respectively only for long term paper feed during the calibration routine. In the short term, if some error occurs, the corrected value (corrected by the long term feed rate or edge rate found during calibration)
Is out of equalization with the other parameters used to calculate the correction ratios (ER1, ER2, A1).

The feed ratio AR and the edge ratios ER1, ER2 can be calculated equally as inverse ratios to those shown, in which case the correction is to multiply E1 by ER1 in one example, E3 in another example ER2.
Multiplication by, in the last example caused by multiplying A1 by AR.

In the routine shown in FIG. 8, the average feed is the raw value of E1 or E3.
Although shown as calculated using the raw value of, it is understood that the average feed can be calculated using the corrected value of E1 and the corrected value of E3.

Initial calibration of the system is established using the routine shown in FIG. FIG. 9 shows how the system continues to self-calibrate during use and withdrawals from normal values are detected.

FIG. 9 is entered via the execution instruction 188 after the exit instruction 186 of FIG. Control was immediately passed to test 190 in Figure 10,
Check the output of the photodetector yoke 90 to see if the line spacing has been achieved. When line feed is achieved,
Control is passed to the twelfth operation 192 to maintain a long table of values found with line spacing.

The long table contains a list of all values of counts drawn from all optical wheels 164 (alternatively 76 where appropriate) for a given number of lines of paper 12. When a new count value for each optical wheel 164 (or 76) is received, the value of the count most recently held in the table corresponding to the particular optical wheel 164 (or 76) is discarded. All other values are moved up one place and the new value is stored as the latest value. This is a standard stacking operation. Thus, for each line feed during operation of printer 16, a new "running average" estimate of the performance of the monitor system is provided.

The twelfth operation 192 passes control to a thirteenth operation 194, where the average feed A1 detected by the first paper movement sensor 18 is
, The average feed A2 detected by the second paper movement sensor 26, the feed ratio AR, the edge ratio E1 of the first paper movement sensor 18, and the edge ratio E2 of the second paper movement sensor 26. Calculated. The calculation is obtained as described above with respect to FIG. The correction of the values to E2 and E4 and to A2 is done as before. Thus the new complete set ratio AR, E
1, E2 and feeds A1, A2 are calculated for each line feed of paper 12 based on the first large predetermined number of feed lines.

A thirteenth operation 194 passes control to a fourteenth operation 196, where the short table is maintained and updated in the same manner as the twelfth operation 192 maintained and updated the long table. That is, for example, a shorter table containing the cumulative pulses received from each optical wheel 194 (where applicable 76) for the previous five rows is provided for each optical wheel 194 (or 76 if appropriate).
The longest existing individual row count of is discarded, all accumulated values are moved up one place, and the update count received for each row feed is stored in place as the youngest value. It

A fourteenth operation 196 passes control to a fifteenth operation 198, which calculates the short-term feed A1 'of the first paper movement sensor 18, the feed A2' of the second movement sensor 26, in a short table. Calculation of the feed ratio AR 'based on the calculation of the edge ratio E1' based on the short table for the first paper movement sensor 18, second paper movement sensor 26
All edge ratio E2 'calculations based on a short table for are performed.

In this way, two values are maintained for each calculated feed ratio. The first value is the long running average for a very large number of paper feed lines. The second value is a short-term value, which in each case is based on relatively little paper feed. Statistical perturbations and temporary false counts cannot drastically change the calculated values of feeds and ratios based on long tables, while the errors remaining for relatively few rows were calculated from short tables. Detected by changing feed and ratio values.
Corrections to counts are obtained using only the ratios (AR, E1, E2) found in the long table. Therefore, the short table cannot hide the paper movement error because its correction ratio (AR ', E1', E2 ') is not used to correct the count (explained in connection with FIG. 8). Thus the long table has control over all the corrections and the short table simply reflects the instantaneous actual situation.

The number of leadings in the long table is conveniently equated with the number of leadings shown in the fourth operation 170 (here selected as 20 leading for exemplary purposes), but the two leadings are The numbers do not have to be equal. The initial calibration routine shown in FIG. 8 can be used as a starting point for the much larger table used in the routine shown in FIG. For example, the first 20 rows shown in Figure 8 could be added to a long table to make it 100 rows, for example, with only 20 values starting with each spacing and a total of 100 values in the long table. Until you get. Once the long table is filled, the routine shown in FIG. 9 begins to discard the longest held count value for each row for the first time. Thus, the short start routine as shown in FIG. 8 can be used to produce the longer start routine shown in FIG.

Further, in the present invention, the first set of values determined in the first calibration routine of FIG. 8 is stored in the monitor logic 28 in a non-volatile manner, and for some reason 20
If you don't want to waste a line or so of paper (or any other paper length that might be useful for the calibration routine of Figure 8), the device will be switched off at the value found so far. The value that is not discarded is used to generate the routine shown in FIG. If the routine of FIG. 9 runs briefly, the stored values are discarded from the calculation to give the true situation of execution of monitors 18, 26, 28.

When the fifteenth operation 198 passes control to the eleventh test 200, the ratio of the paper feed A1 'to the first document movement sensor 18 of the short table and the feed A1 of the first paper movement sensor 18 from the long table is: It is compared with a predetermined limit. If the value of the ratio of the eleventh test 200 is outside the upper or lower bound (ie, not within the predetermined bounds), the operation is moved to a sixteenth operation 202 to give an indication of an error at the paper input. If the ratio is less than the lower limit, then there is evidence of paper deposits, tears in the print well 36, pinch wheel 38 slippage, and paper 12 out of supply. If the ratio of the 11th test 200 exceeds the upper limit, the paper 12 will be pinched by the pinch wheel 3
Wound around one of the eight or pinch wheels 3
Anomalous paper feed conditions in print well 36 are shown such that 8 does not have enough time to grab the paper and prevent paper 12 from being pulled between printers 16 by some external means.

If the ratio from the eleventh test 200 is within limits, control passes to the twelfth test 204. The sixteenth operation 202 also transfers control to the first test 204. In the twelfth test 204, the paper feed A2 ′ found from the short display of the second paper movement sensor 26.
Value and the found feed value A2 of the second paper movement sensor 26 from the long table are taken and tested to see if they are within predetermined limits, ie between the upper and lower limits. To do. If the ratio found in the twelfth test 204 is not within the predetermined limits, control is passed to a seventeenth operation 206 to display an error display 30 indicating that a paper misalignment deposited at the paper exit was found. And to the printer control processor 22. If the ratio found in the twelfth test 204 is less than the lower limit, a seventeenth operation 206 provides an indication of paper tear or paper jam or stack in the print well 36 after the pinch wheel 38. Eleventh test due to lack of paper movement
If found in both the 200 and twelfth tests 204, the seventeenth action 206 indicates a general jam condition. Alternatively, under these circumstances, the seventeenth act 206 may also indicate the possibility of out of paper. If the ratio tested in the twelfth test 204 exceeds the upper limit, the seventeenth operation 206 provides an indication that an improper rapid paper feed was experienced by the second paper movement sensor 26. If the eleventh test 200 has previously detected an unwarranted rapid paper movement, the seventeenth operation 206 may indicate that some external cause pulls the paper 12 from the printer 16 and the pinch wheel 38 resists that pull. Gives an indication that you cannot.

If the twelfth test 204 finds that parameter is within predetermined limits, control is passed to the thirteenth test 208. Similarly, the seventeenth operation 206 passes control to the thirteenth test 208. Here the ratio between the found edge ratio E1 'for the first paper movement sensor 18 from the short table and the found edge ratio E1 of the first paper movement sensor 18 from the long table is tested. Tested to see if they are within predetermined limits. If the ratio found by the thirteenth test is outside the predetermined limits, control is passed to the eighteenth operation 210 and the monitor logic 28 causes the error display 30 to indicate that the accumulated paper skew has occurred at the input platform 34. And to the printer control processor 22.

If the ratio found in thirteenth test 208 is within its predetermined limits, control is passed to fourteenth test 212.
The eighteenth operation 210 also passes control to the fourteenth test 212.

The fourteenth test 212 is the edge ratio E2 'found for the second paper movement sensor 26 from the short table and the edge ratio E2 found for the second paper movement sensor 26 from the long table. Test the ratio between to see if it is within predetermined limits. If the ratio found in the fourteenth test 212 is outside the predetermined limits, control is passed to the nineteenth operation 214, where the monitor logic 28 indicates that the paper skew accumulated at the exit platform 46 has appeared. An error display 30 and print control processor 22 are shown. 13th test 208 and 14th test 212
19th behavior, with each showing obvious paper distortion on the same side
214 indicates that the paper 12 has moved from the printer 16 to one side for some reason. This can occur, for example, when the paper roll 10 is inadvertently placed on one side of its central position.

If the ratio found in the fourteenth test 212 is within that limit, control is passed to the fifteenth test 216. The nineteenth operation 214 also passes control to the fifteenth test 216. Fifteenth test 21
6 is between the feed ratio AR ′ found for the whole system from the short table (according to the description relating to FIG. 8) and the feed ratio AR found for the whole system from the long table. Take the ratio and test to see if it is within predetermined limits. If it is not within the predetermined limit, control is passed to the twentieth operation 218 and the monitor logic 28 determines the mutual movement detection ratio measured between the first paper movement sensor 28 and the second paper movement sensor 26. An error display 30 and printer control processor 22 are provided with an indication that an error has occurred in the paper feed.

If the tested ratio in the fifteenth test is found to be within predetermined limits, control is passed to the tenth test 190.
Similarly, the twentieth operation 218 returns control to the tenth test 190.

The routine performed in accordance with FIG. 9 is a very sensitive test for accumulated paper feed errors in the paper movement monitor system. Long-term changes such as wheel diameter wear, debris accumulation, etc. can be accommodated as the system continuously self-calibrates. For example, if a piece of paper sticks to one of the wheels for some reason,
If the change in wheel diameter is not large enough to give an error indication, the change in wheel diameter will quickly become transparent in later movements. Similarly, if for some reason the pinch wheel 38 changes its diameter (or therefore changes the size of the line feed), the system itself recalibrates very quickly to make the line length transparent. In particular, the system thus described can be applied virtually to any printer with any line length, and the routines associated with FIGS. Ensure that it is achieved quickly regardless of the parameters of.

The individual features of novelty described above can be applied alone or in any combination in embodiments of the invention.

Claims (22)

(57) [Claims] 1. A device for monitoring paper movement in a printer, wherein the device is operative to engage the paper at a first point in the printer and wherein the first line is printed during successive line printing. A first movement sensor operable to detect a distance traveled by the paper at a point, said first sensor comprising first roll means for rolling relative to the paper being fed and said first roll means. First rotation detection means for providing an output indication of the angular movement of the device, the apparatus comprising: paper feed if the sum of the outputs of the first rotation detection means is not within first and second predetermined limits. An error indication is provided, and the device further operates to engage the paper at the second point with the printer and to detect the distance traveled by the paper at the second point between successive line prints. Including a second movement sensor that operates in The sensor includes second roll means for rolling with respect to the feed sheet and second rotation detection means for providing an output indicative of angular movement of the second roll means, the apparatus comprising the first rotation. A first sum of outputs of the detecting means is obtained, a second sum of outputs of the second rotation detecting means is obtained, and a difference between the first sum and the second sum exceeds a predetermined magnitude. A self-calibration by finding a ratio between the sums of the outputs of the first and second rotation detection means and establishing a feed ratio, and 1 or the feed ratio is multiplied by the sum of the outputs of the second rotation detecting means to normalize the output of the first rotation detecting means with the output of the second rotation detecting means. Works on a device. 2. A first sole wheel rotation wherein said first roll means includes a first sole wheel and said first rotation detection means is coupled to monitor rotation of said first sole wheel. The apparatus of claim 1 including a detector. 3. A second sole wheel rotation, wherein the second roll means includes a second sole wheel and the second rotation detection means is coupled to monitor rotation of the second sole wheel. The apparatus of claim 2 including a detector. 4. A paper movement according to a second print line number smaller than the first print line number, which operates to form a long-term value of the feed ratio based on the paper move according to the first print line number. Operative to form a short-term value of the feed ratio based on the first being that the ratio between the long-term value of the feed ratio and the short-term value of the feed ratio is outside a predetermined upper and lower value. An apparatus as claimed in claim 2 or 3, which is operative to indicate a paper movement problem between the second sensor and the second sensor. 5. A second operation that is operable to form a long-term sum of the distances detected by the first sensor based on paper movement according to a first number of print lines, the second number being less than the first number of print lines. Operative to form a short-term sum of the distances detected by the first sensor based on paper movement according to the number of printing lines of the first sensor and the long-term value of the distance and the first value of the distance detected by the first sensor. 5. The method of claim 1, wherein the ratio between the short-term values of the distance detected by the sensor of 1 is operative to indicate a paper movement error if the ratio is outside a predetermined upper or lower value. Equipment. 6. A second operation operative to form a long-term sum of said distances detected by said second sensor based on paper movement by a first number of print lines, a second number smaller than said first number of print lines. Operative to form a short-term sum of the distances detected by the second sensor based on paper movement according to the number of print lines of the second sensor and the long-term value of the distance detected by the second sensor. 6. The method of any of claims 1-5, wherein the ratio between the short-term values of the distance detected by two sensors is outside the predetermined upper or lower value to indicate a paper movement error. Equipment. 7. The first and second roll means are spaced apart transversely to the direction of paper movement and each is operative to engage the paper near its respective edge.
Edge wheel, a first edge wheel rotation detector for providing an output indicative of rotation of the first edge wheel, and a first edge wheel rotation detector for providing an output indicative of rotation of the second edge wheel. Two edge wheel rotation detectors, operative to determine the sum of the rotations indicated by said first edge wheel rotation detector, and rotation indicated by said second edge wheel rotation detector. And summing the ratio of the output of the first edge wheel rotation detector to the sum of the output of the second edge wheel rotation detector. 2. The method of claim 1 operative to form an edge ratio of 1 and thereafter operative to multiply the output of the first or second edge wheel rotation detector to equalize sensitivity therebetween. Equipment. 8. The average of the sum of the outputs of the first edge wheel rotation detector and the sum of the outputs of the second edge wheel rotation detector as the output of the rotation detector. 8. The device of claim 7, operative to provide a value. 9. Paper when a difference between the sum of the outputs of the first edge wheel rotation detector and the sum of the outputs of the second edge wheel rotation detector exceeds a predetermined limit. 9. A device as claimed in claim 7 or 8 which operates to provide an output indicative of distortion.
An apparatus according to claim 1. 10. A paper with a second print line number that is operative to form a long-term value of the first edge ratio based on paper movement with the first print line number and is smaller than the first print line number. Operative to form a short-term value of the first edge ratio based on movement, wherein a ratio between the long-term value of the first edge ratio and the short-term value of the first edge ratio is predetermined. 8. Operate to indicate paper distortion when outside of upper and lower values.
8. The device according to 8 or 9. 11. Third and fourth edges spaced apart across the direction of paper movement in which the second roll means each operates to engage the paper near its respective edge. A second wheel detecting means for providing a rotation indicative of rotation of the third edge wheel and a third edge wheel rotation detector for providing an output indicative of rotation of the fourth edge wheel. A fourth edge wheel rotation detector for operating to sum the rotations indicated by the third edge wheel rotation detector, and by the fourth edge wheel rotation detector. Operative to determine the sum of rotations indicated, and determining the ratio between the sum of the outputs of the third edge wheel rotation detector and the sum of the outputs of the fourth edge wheel rotation detector. So as to form the second edge ratio Was created, then operates to equalize therebetween sensitivity by multiplying the output of said third or said fourth edge wheel rotation detector, according to claim 1 and 7,
The apparatus according to 8, 9, or 10. 12. An average of the sum of the outputs of the third edge wheel rotation detector and the sum of the outputs of the fourth edge wheel rotation detector as the output of the rotation detecting means. 13. The device of claim 11, operative to provide a value. 13. A paper distortion occurs when a difference between the sum of the outputs of the third edge wheel rotation detector and the sum of the outputs of the fourth edge wheel rotation detector exceeds a predetermined limit. 13. A device according to claim 11 or 12 operative to provide the indicated output. 14. A second print line number that is operative to form a long-term value of the second edge ratio based on paper movement by the first print line number and is less than the first print line number. Operative to form a short-term value of the second edge ratio based on paper movement, the long-term value of the second edge ratio and the second value of the second edge ratio.
14. The apparatus of claim 11, 12 or 13 operative to indicate paper skew when the ratio between the short-term values of the edge ratio of is outside the predetermined upper and lower values. 15. The apparatus of claim 4, wherein the long-term and short-term values of the feed ratio are first established in a calibration routine involving paper movement by the first number of lines. 16. The long-term and short-term sums of the movements detected by the first sensor are first established in a calibration routine involving paper movement by the first number of rows. The device according to 15. 17. The method of claim 6, wherein the long-term and short-term sums of the movements detected by the second sensor are first established by a calibration routine involving paper movements by the first number of rows. The device according to 15 or 16. 18. The long-term and short-term values of the first edge ratio are initially established by a calibration routine involving paper movement by the first number of lines.
Device according to claim 10, 15, 16 or 17. 19. The long-term and short-term values of the second edge ratio are first established by a calibration routine involving paper movement by the first number of lines.
Device according to claim 14, 15, 16 or 17. 20. The first sensor includes a first sensor housing that spans a feed in a printer, the first sensor housing including a set of support arms for engaging either side of the printer. Device according to any of claims 1 to 19. 21. The second sensor includes a second sensor housing that spans a paper feed, the second sensor housing including a pair of support arms, the first sensor housing including the second sensor. 21. The device of claim 20, engaging the first sensor housing to support the housing. 22. The second sensor housing is identical in outline to the first sensor housing.
The device according to 21.