US20090072475A1 - Sheet overlap detection apparatus and sheet overlap detection method - Google Patents

Sheet overlap detection apparatus and sheet overlap detection method Download PDF

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Publication number
US20090072475A1
US20090072475A1 US12/284,005 US28400508A US2009072475A1 US 20090072475 A1 US20090072475 A1 US 20090072475A1 US 28400508 A US28400508 A US 28400508A US 2009072475 A1 US2009072475 A1 US 2009072475A1
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Prior art keywords
amplifier
output
value
amplification factor
overlap detection
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US12/284,005
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English (en)
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Masato Sawada
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Komori Corp
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Komori Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H7/00—Controlling article feeding, separating, pile-advancing, or associated apparatus, to take account of incorrect feeding, absence of articles, or presence of faulty articles
    • B65H7/02—Controlling article feeding, separating, pile-advancing, or associated apparatus, to take account of incorrect feeding, absence of articles, or presence of faulty articles by feelers or detectors
    • B65H7/06—Controlling article feeding, separating, pile-advancing, or associated apparatus, to take account of incorrect feeding, absence of articles, or presence of faulty articles by feelers or detectors responsive to presence of faulty articles or incorrect separation or feed
    • B65H7/12—Controlling article feeding, separating, pile-advancing, or associated apparatus, to take account of incorrect feeding, absence of articles, or presence of faulty articles by feelers or detectors responsive to presence of faulty articles or incorrect separation or feed responsive to double feed or separation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
    • G01B17/02—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations for measuring thickness
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2511/00—Dimensions; Position; Numbers; Identification; Occurrences
    • B65H2511/50—Occurence
    • B65H2511/52—Defective operating conditions
    • B65H2511/524—Multiple articles, e.g. double feed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2515/00—Physical entities not provided for in groups B65H2511/00 or B65H2513/00
    • B65H2515/82—Sound; Noise
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2553/00—Sensing or detecting means
    • B65H2553/30—Sensing or detecting means using acoustic or ultrasonic elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2557/00—Means for control not provided for in groups B65H2551/00 - B65H2555/00
    • B65H2557/30—Control systems architecture or components, e.g. electronic or pneumatic modules; Details thereof

Definitions

  • the present invention relates to a sheet overlap detection apparatus and sheet overlap detection method using an ultrasonic wave.
  • the paper sheet overlap detection is normally done using a projector and a photodetector.
  • a projector is arranged on the lower surface side of the feeding table near the front lay.
  • a through hole is formed at a predetermined portion of the feeding table so as to face the light-emitting unit of the projector.
  • a photodetector is arranged on the upper surface side of the feeding table so as to face the through hole. That is, the projector projects light in the thickness direction of a paper sheet to be fed.
  • the photodetector receives the light transmitted through the fed paper sheet.
  • the light is converted into an electrical signal.
  • An output level corresponding to the received light amount that is obtained as the electrical signal is compared with a preset determination level. Overlap of the fed paper sheets is detected based on the comparison result (Japanese Patent Laid-Open Nos. 2-178145 and 63-290746).
  • the overlap detection apparatus using an ultrasonic wave comprises an ultrasonic transmitter which transmits an ultrasonic wave, and an ultrasonic receiver which receives the ultrasonic wave from the ultrasonic transmitter. On the basis of the reception level of the ultrasonic wave received by the ultrasonic receiver, the apparatus detects overlap of fed paper sheets which pass between the ultrasonic transmitter and the ultrasonic receiver.
  • FIG. 23 shows an example of the conventional overlap detection apparatus using an ultrasonic wave.
  • the overlap detection apparatus comprises an ultrasonic transmitter 501 , an ultrasonic receiver 502 , and a control unit 503 attached to the ultrasonic transmitter 501 and the ultrasonic receiver 502 .
  • the control unit 503 comprises a processing unit 503 A, ultrasonic oscillation circuit 503 B, and amplification circuit 503 C.
  • the amplification circuit 503 C comprises a first amplifier (fixed amplifier) AMP 501 and a second amplifier (variable amplifier) AMP 502 .
  • the ultrasonic oscillation circuit 503 B supplies a driving frequency f to the ultrasonic transmitter 501 .
  • the ultrasonic transmitter 501 Upon receiving the driving frequency f from the ultrasonic oscillation circuit 503 B, the ultrasonic transmitter 501 emits an ultrasonic wave of output level determined by the driving frequency f ( FIG. 24 ).
  • the ultrasonic receiver 502 receives the ultrasonic wave emitted from the ultrasonic transmitter 501 and sends a reception output RV corresponding to the ultrasonic wave reception amount to the amplification circuit 503 C.
  • the amplification circuit 503 C amplifies the reception output RV from the ultrasonic receiver 502 and sends, to the processing unit 503 A, output values AP 501 and AP 502 representing the ultrasonic wave reception level in the ultrasonic receiver 502 . Based on the output values AP 501 and AP 502 from the amplification circuit 503 C, the processing unit 503 A detects overlap of fed paper sheets 504 which pass between the ultrasonic transmitter 501 and the ultrasonic receiver 502 .
  • FIGS. 25A and 25B show the changes of the output values AP 501 and AP 502 from the amplification circuit 503 C when one paper sheet 504 is fed.
  • FIGS. 26A and 26B show the changes of the output values AP 501 and AP 502 from the amplification circuit 503 C when two paper sheets 504 are fed.
  • the output value AP 501 of the amplification circuit 503 C is defined to be a set value V 1 s when no fed paper sheet 504 is sandwiched between the ultrasonic transmitter 501 and the ultrasonic receiver 502 .
  • the output value AP 502 of the amplification circuit 503 C is defined to be a set value V 2 s when one fed paper sheet 504 is sandwiched between the ultrasonic transmitter 501 and the ultrasonic receiver 502 .
  • Values about 80% of the set values V 1 s and V 2 s are set as threshold values Vth 1 and Vth 2 .
  • the fed paper sheet 504 which is inserted between the ultrasonic transmitter 501 and the ultrasonic receiver 502 reflects the ultrasonic wave. Hence, the ultrasonic wave reception amount in the ultrasonic receiver 502 decreases. In this case, when one paper sheet 504 is inserted between the ultrasonic transmitter 501 and the ultrasonic receiver 502 , the attenuation amount of the ultrasonic wave reception amount in the ultrasonic receiver 502 is small ( FIG. 27A ).
  • the output value AP 501 of the amplification circuit 503 C is smaller than the threshold value Vth 1 ( FIG. 25A : point t 1 ).
  • the output value AP 502 of the amplification circuit 503 C keeps the threshold value Vth 2 or more ( FIG. 25B : point t 1 ).
  • the processing unit 503 A monitors the output values AP 501 and AP 502 from the amplification circuit 503 C and detects overlap of the fed paper sheets 504 when the output value AP 501 is smaller than the threshold value Vth 1 , and the output value AP 502 is also smaller than the threshold value Vth 2 .
  • the amplification factor GA of the amplifier AMP 502 in the amplification circuit 503 C is limited. This makes it impossible to detect specialty paper such as microflute having a high ultrasonic wave attenuation factor, and degrades the detection accuracy.
  • the present invention has been made to solve the above-described problems, and has as its object to provide a sheet overlap detection apparatus and sheet overlap detection method capable of accurately detecting overlap of even specialty paper having a high ultrasonic wave attenuation factor.
  • a sheet overlap detection apparatus comprising an ultrasonic transmitter which transmits an ultrasonic wave, an ultrasonic receiver which receives the ultrasonic wave from the ultrasonic transmitter, a first amplifier which amplifies an output from the ultrasonic receiver, a second amplifier which is configured to freely change an amplification factor and amplifies an output from the first amplifier, a third amplifier which amplifies an output from the second amplifier, amplification factor control means for changing the amplification factor of the second amplifier, first overlap detection monitor output decision means for deciding the output from the second amplifier as a sheet overlap detection monitor output when the amplification factor control means adjusts the amplification factor of the second amplifier, and an output value of the second amplifier has become almost equal to a first set value while one sheet is sandwiched between the ultrasonic transmitter and the ultrasonic receiver, second overlap detection monitor output decision means for deciding an output from the third amplifier as a sheet overlap detection monitor output when the amplification factor control means adjusts the amplification
  • a sheet overlap detection method comprising the steps of causing an ultrasonic transmitter to transmit an ultrasonic wave, causing an ultrasonic receiver to receive the ultrasonic wave from the ultrasonic transmitter, causing a first amplifier to amplify an output from the ultrasonic receiver, causing a second amplifier to amplify an output from the first amplifier, causing a third amplifier to amplify an output from the second amplifier, adjusting an amplification factor of the second amplifier, deciding the output from the second amplifier as a sheet overlap detection monitor output when the amplification factor of the second amplifier is adjusted, and an output value of the second amplifier has become almost equal to a first set value while one sheet is sandwiched between the ultrasonic transmitter and the ultrasonic receiver, deciding an output from the third amplifier as a sheet overlap detection monitor output when the amplification factor of the second amplifier is adjusted, and the output value of the second amplifier has not become almost equal to the first set value, but an output value of the third amplifier has become almost equal to a second set value while one sheet
  • FIG. 1 is a block diagram showing an overlap detection apparatus according to the first embodiment of the present invention
  • FIGS. 2A and 2B are flowcharts for explaining an overlap detection monitor output & amplification factor decision processing operation executed by the processing unit of the overlap detection apparatus shown in FIG. 1 ;
  • FIGS. 3A to 3C are timing charts for explaining an example of the overlap detection monitor output & gain decision process of the overlap detection apparatus shown in FIG. 1 , in which the output from a second amplifier is decided as an overlap detection monitor output;
  • FIGS. 4A to 4D are timing charts for explaining an example of the overlap detection monitor output & gain decision process of the overlap detection apparatus shown in FIG. 1 , in which the output from a third amplifier is decided as an overlap detection monitor output;
  • FIG. 5 is a block diagram of an overlap detection monitor output & amplification factor decision unit
  • FIG. 6 is a block diagram showing an overlap detection apparatus according to the second embodiment of the present invention.
  • FIG. 7 is a view showing the arrangement of memories in the overlap detection apparatus shown in FIG. 6 ;
  • FIG. 8 is a block diagram showing the arrangement of a printing press control apparatus connected to the overlap detection apparatus shown in FIG. 6 ;
  • FIGS. 9A to 9O are flowcharts illustrating a processing operation according to an overlap detection program executed by the CPU of the overlap detection apparatus shown in FIG. 6 ;
  • FIGS. 10A to 10C are flowcharts illustrating a processing operation executed by the CPU of the printing press control apparatus shown in FIG. 8 ;
  • FIGS. 11A to 11C are timing charts for explaining a first example of the overlap detection monitor output & gain decision process of the overlap detection apparatus shown in FIG. 6 , in which the output from a second amplifier is decided as an overlap detection monitor output;
  • FIGS. 12A to 12C are timing charts for explaining a second example of the overlap detection monitor output & gain decision process of the overlap detection apparatus shown in FIG. 6 , in which the output from the second amplifier is decided as an overlap detection monitor output;
  • FIGS. 13A to 13C are timing charts for explaining a third example of the overlap detection monitor output & gain decision process of the overlap detection apparatus shown in FIG. 6 , in which the output from the second amplifier is decided as an overlap detection monitor output;
  • FIGS. 14A to 14C are timing charts for explaining a fourth example of the overlap detection monitor output & gain decision process of the overlap detection apparatus shown in FIG. 6 , in which the output from the second amplifier is decided as an overlap detection monitor output;
  • FIGS. 15A to 15D are timing charts for explaining a first example of the overlap detection monitor output & gain decision process of the overlap detection apparatus shown in FIG. 6 , in which the output from a third amplifier is decided as an overlap detection monitor output;
  • FIGS. 16A to 16D are timing charts for explaining a second example of the overlap detection monitor output & gain decision process of the overlap detection apparatus shown in FIG. 6 , in which the output from the third amplifier is decided as an overlap detection monitor output;
  • FIGS. 17A to 17D are timing charts for explaining a third example of the overlap detection monitor output & gain decision process of the overlap detection apparatus shown in FIG. 6 , in which the output from the third amplifier is decided as an overlap detection monitor output;
  • FIGS. 18A to 18D are timing charts for explaining a fourth example of the overlap detection monitor output & gain decision process of the overlap detection apparatus shown in FIG. 6 , in which the output from the third amplifier is decided as an overlap detection monitor output;
  • FIGS. 19A and 19B are graphs showing the changes of the output value of a first amplifier when a driving frequency to an ultrasonic transmitter is changed stepwise;
  • FIG. 20 is a block diagram of functions implemented by the CPU of the overlap detection apparatus shown in FIG. 6 ;
  • FIG. 21 is a block diagram of an overlap detection monitor output & amplification factor decision unit
  • FIG. 22 is a block diagram of an amplification factor control unit
  • FIG. 23 is a block diagram showing an example of a conventional overlap detection apparatus using an ultrasonic wave
  • FIG. 24 is a view showing a state in which an ultrasonic transmitter emits an ultrasonic wave to an ultrasonic receiver
  • FIGS. 25A and 25B are timing charts showing the changes of output values of an amplification circuit when one paper sheet is fed;
  • FIGS. 26A and 26B are timing charts showing the changes of the output values of the amplification circuit when two paper sheets are fed.
  • FIGS. 27A and 27B are views showing the changes of an ultrasonic wave reception amount for one fed paper sheet and two fed paper sheets.
  • FIG. 1 shows an overlap detection apparatus according to the first embodiment of the present invention.
  • the overlap detection apparatus comprises an ultrasonic transmitter (ultrasonic transmission sensor) 1 which transmits an ultrasonic wave, an ultrasonic receiver (ultrasonic reception sensor) 2 which receives the ultrasonic wave from the ultrasonic transmitter 1 , and a control unit 3 attached to the ultrasonic transmitter 1 and the ultrasonic receiver 2 .
  • the control unit 3 comprises a processing unit 3 A, ultrasonic oscillation circuit 3 B, and amplification circuit 3 C.
  • the amplification circuit 3 C comprises a first amplifier AMP 1 which amplifies the output from the ultrasonic receiver 2 , a second amplifier AMP 2 which amplifies the output from the first amplifier AMP 1 , and a third amplifier AMP 3 which amplifies the output from the second amplifier AMP 2 .
  • the first and third amplifiers AMP 1 and AMP 3 are fixed amplifiers having fixed amplification factors.
  • the second amplifier AMP 2 is a variable amplifier capable of freely changing the amplification factor.
  • the ultrasonic oscillation circuit 3 B supplies a driving frequency f to the ultrasonic transmitter 1 .
  • the ultrasonic transmitter 1 Upon receiving the driving frequency f from the ultrasonic oscillation circuit 3 B, the ultrasonic transmitter 1 emits an ultrasonic wave of output level determined by the driving frequency f.
  • the ultrasonic receiver 2 receives the ultrasonic wave emitted from the ultrasonic transmitter 1 and sends a reception output RV corresponding to the ultrasonic wave reception amount to the amplification circuit 3 C.
  • the amplification circuit 3 C amplifies the reception output RV from the ultrasonic receiver 2 and sends, to the processing unit 3 A, output values AP 1 , AP 2 , and AP 3 representing the ultrasonic wave reception levels in the ultrasonic receiver 2 .
  • the processing unit 3 A Based on the output values AP 1 , AP 2 , and AP 3 from the amplification circuit 3 C, the processing unit 3 A detects overlap of fed paper sheets 4 which pass between the ultrasonic transmitter 1 and the
  • the amplification circuit 3 C includes the third amplifier AMP 3 .
  • the third amplifier AMP 3 is connected to the output of the second amplifier AMP 2 .
  • the output value AP 3 from the third amplifier AMP 3 is supplied to the processing unit 3 A.
  • the processing unit 3 A includes an overlap detection monitor output & amplification factor decision unit 30 .
  • the overlap detection monitor output & amplification factor decision unit 30 decides one of the output value AP 2 of the second amplifier AMP 2 and the output value AP 3 of the third amplifier AMP 3 as an overlap detection monitor output and also decides an overlap detection amplification factor GA of the second amplifier AMP 2 .
  • FIGS. 2A and 2B show the overlap detection monitor output & amplification factor decision processing operation of the overlap detection monitor output & amplification factor decision unit 30 in the processing unit 3 A.
  • the overlap detection monitor output & amplification factor decision unit 30 is implemented as a processing operation of a CPU according to a program stored in a memory of the processing unit 3 A.
  • the processing unit 3 A has a switch SW 1 to instruct the overlap detection monitor output & amplification factor decision processing operation.
  • the ultrasonic transmitter 1 is emitting an ultrasonic wave upon receiving the driving frequency f from the ultrasonic oscillation circuit 3 B. Additionally, one paper sheet 4 is fed between the ultrasonic receiver 2 and the ultrasonic transmitter 1 which is emitting the ultrasonic wave.
  • the processing unit 3 A receives the output value AP 1 from the first amplifier AMP 1 ( FIG. 2A : step S 1 ) and compares it with a threshold value Vth 1 (step S 2 ). If the output value AP 1 of the first amplifier AMP 1 is smaller than the threshold value Vth 1 (YES in step S 2 , FIG. 3A : point t 1 ), it is determined that one fed paper sheet 4 is sandwiched between the ultrasonic transmitter 1 and the ultrasonic receiver 2 .
  • the processing unit 3 A Upon determining that one fed paper sheet 4 is sandwiched between the ultrasonic transmitter 1 and the ultrasonic receiver 2 (YES in step S 2 ), the processing unit 3 A sets a count value N to 0 (step S 3 ). The processing unit confirms that the count value N does not satisfy N>255 (NO in step S 4 ) and sets the amplification factor GA of the second amplifier AMP 2 to GA 0 (minimum value) (step S 5 , FIG. 3C : point t 1 ).
  • the processing unit sets the paper type to plain paper (step S 11 ), decides the output from the second amplifier AMP 2 as the overlap detection monitor output (step S 12 ), decides GAsp as the overlap detection amplification factor (step S 13 ), and decides the threshold value Vth 2 as the overlap detection threshold value (step S 14 ).
  • the process advances to step S 15 ( FIG. 2B ) to set the count value N to 0.
  • the processing unit confirms that the count value N does not satisfy N>255 (NO in step S 16 ) and sets the amplification factor GA of the second amplifier AMP 2 to GA 0 (minimum value) (step S 17 , FIG. 4D : point t 2 ).
  • the processing unit sets the paper type to specialty paper (step S 23 ), decides the output from the third amplifier AMP 3 as the overlap detection monitor output (step S 24 ), decides GAsp as the overlap detection amplification factor (step S 25 ), and decides the threshold value Vth 3 as the overlap detection threshold value (step S 26 ).
  • step S 16 determines that detection is disabled. That is, if the output value AP 3 of the third amplifier AMP 3 is not equal to the set value V 3 s, either, the processing unit determines that overlap detection at an appropriate accuracy is disabled, and displays, e.g., an error message.
  • the output from the second amplifier AMP 2 is decided as the overlap detection monitor output.
  • the output from the third amplifier AMP 3 is decided as the overlap detection monitor output. This makes it possible to accurately detect overlap of paper sheets in a wide range including specialty paper.
  • FIG. 5 shows the functional blocks of the overlap detection monitor output & amplification factor decision unit 30 in the processing unit 3 A.
  • the overlap detection monitor output & amplification factor decision unit 30 comprises an amplification factor control unit 31 , first overlap detection monitor output & amplification factor decision unit 32 , and second overlap detection monitor output & amplification factor decision unit 33 .
  • the amplification factor control unit 31 raises the amplification factor GA of the second amplifier AMP 2 stepwise from GA 0 to GA 255 .
  • the amplification factor control unit 31 performs the processes in, e.g., steps S 5 and S 17 .
  • the first overlap detection monitor output & amplification factor decision unit 32 decides the output of the second amplifier AMP 2 as the overlap detection monitor output when the output value AP 2 of the second amplifier AMP 2 is recognized to be almost equal to the set value V 2 s halfway through the process of causing the amplification factor control unit 31 to raise the amplification factor GA of the second amplifier AMP 2 stepwise from GA 0 to GA 255 .
  • the first overlap detection monitor output & amplification factor decision unit 32 also receives the amplification factor GA N of the second amplifier AMP 2 at that time and decides the received amplification factor GA N as the overlap detection amplification factor GAsp.
  • the first overlap detection monitor output & amplification factor decision unit 32 sends an instruction to the amplification factor control unit 31 to make it again raise the amplification factor GA of the second amplifier AMP 2 stepwise from GA 0 to GA 255 .
  • the first overlap detection monitor output & amplification factor decision unit 32 comprises a first equivalence determination unit 32 A, first overlap detection monitor output decision unit 32 B, and first overlap detection amplification factor decision unit 32 C.
  • the first equivalence determination unit 32 A performs the process in, e.g., step S 7 .
  • the first overlap detection monitor output decision unit 32 B performs the process in, e.g., step S 12 .
  • the first overlap detection amplification factor decision unit 32 C performs the process in, e.g., step S 13 .
  • the second overlap detection monitor output & amplification factor decision unit 33 decides the output from the third amplifier AMP 3 as the overlap detection monitor output when the output value AP 3 of the third amplifier AMP 3 is recognized to be almost equal to the set value V 3 s halfway through the process of causing the amplification factor control unit 31 to raise the amplification factor GA of the second amplifier AMP 2 stepwise from GA 0 to GA 255 .
  • the second overlap detection monitor output & amplification factor decision unit 33 also receives the amplification factor GA N of the second amplifier AMP 2 at that time and decides the received amplification factor GA N as the overlap detection amplification factor GAsp.
  • the second overlap detection monitor output & amplification factor decision unit 33 determines that detection is disabled.
  • the second overlap detection monitor output & amplification factor decision unit 33 comprises a second equivalence determination unit 33 A, second overlap detection monitor output decision unit 33 B, second overlap detection amplification factor decision unit 33 C, and detection disable determination unit 33 D.
  • the second equivalence determination unit 33 A performs the process in, e.g., step S 19 .
  • the second overlap detection monitor output decision unit 33 B performs the process in, e.g., step S 24 .
  • the second overlap detection amplification factor decision unit 33 C performs the process in, e.g., step S 25 .
  • the detection disable determination unit 33 D performs the process in, e.g., step S 27 .
  • the amplification factor GA of the second amplifier AMP 2 is raised stepwise from GA 0 to GA 255 .
  • the amplification factor GA is set to GA 128 first. If the output value AP 2 of the second amplifier AMP 2 at that time is smaller than the set value V 2 s, the amplification factor GA is raised to GA 192 .
  • the amplification factor GA may be narrowed down in this way until the output value AP 2 of the second amplifier AMP 2 almost equals the set value V 2 s. This method will be described later in the second embodiment. This method can greatly speed up the processing as compared to the method of changing the amplification factor GA step by step.
  • the amplification factor GA of the second amplifier AMP 2 is raised again stepwise from GA 0 to GA 255 thereby searching for a point where the output value AP 3 of the third amplifier AMP 3 satisfies AP 3 ⁇ V 3 s .
  • the output value AP 2 of the second amplifier AMP 2 and the output value AP 3 of the third amplifier AMP 3 are stored while raising the amplification factor GA of the second amplifier AMP 2 stepwise from GA 0 to GA 255 .
  • the output value AP 2 of the second amplifier AMP 2 and the output value AP 3 of the third amplifier AMP 3 corresponding to the amplification factors GA 0 to GA 255 are observed.
  • the output from the second amplifier AMP 2 is decided as the overlap detection monitor output.
  • the output from the third amplifier AMP 3 may be decided as the overlap detection monitor output. This obviates changing the amplification factor GA of the second amplifier AMP 2 again and speeds up the processing.
  • an overlap detection unit 34 in the processing unit 3 A detects overlap of the fed paper sheets 4 which pass between the ultrasonic transmitter 1 and the ultrasonic receiver 2 .
  • FIG. 6 shows an overlap detection apparatus according to the second embodiment of the present invention.
  • An overlap detection apparatus 100 is connected to a printing press control apparatus 200 and comprises a CPU 101 , ROM 102 , RAM 103 , input device 104 , display device 105 , output device 106 , VCO (voltage to frequency converter) D/A converter 107 , VCO 108 , ultrasonic oscillation circuit 109 , ultrasonic transmission sensor (ultrasonic transmitter) 110 , ultrasonic reception sensor (ultrasonic receiver) 111 , first amplifier (fixed amplifier) 112 (AMP 1 ), second amplifier (variable amplifier) 113 (AMP 2 ), third amplifier (fixed amplifier) 114 (AMP 3 ), D/A converter 115 for second amplifier gain adjustment, printing press rotation phase detection counter 116 , printing press rotation phase detection rotary encoder 117 , A/D converters 118 to 120 , interfaces 121 to 128 , and memory M.
  • Examples of the output device 106 are an FD driver and a printer.
  • FIG. 7 shows the arrangement of the memory M.
  • the memory M comprises a memory Ml for storing a count value N corresponding to the maximum output value of the ultrasonic reception sensor, a memory M 2 for storing the maximum output value of the ultrasonic reception sensor, a memory M 3 for storing the count value N, a memory M 4 for storing the output value of the first amplifier, a memory M 5 for storing the optimum driving frequency value of the ultrasonic transmission sensor, a memory M 6 for storing the correction value of the count value N, a memory M 7 for storing a paper presence determination threshold value, a memory M 8 for storing the output value of the second amplifier, a memory M 9 for storing an optimum gain value determination reference value, a memory M 10 for storing the difference to the optimum gain value determination reference value, a memory M 11 for storing the absolute value of the difference to the optimum gain value determination reference value, a memory M 12 for storing an optimum gain value determination threshold value, a memory M 13 for storing the next correction
  • the memory Ml stores a count value NRmax corresponding to the maximum output value of the ultrasonic reception sensor.
  • the memory M 2 stores a maximum output value AP 1 max of the ultrasonic reception sensor.
  • the memory M 3 stores the count value N.
  • the memory M 4 stores an output value AP 1 of the first amplifier.
  • the memory M 5 stores an optimum driving frequency value Nsp of the ultrasonic transmission sensor.
  • the memory M 6 stores a correction value NC of the count value N.
  • the memory M 7 stores a paper presence determination threshold value Vth 1 .
  • the memory M 8 stores an output value AP 2 of the second amplifier.
  • the memory M 10 stores a difference ⁇ Vs between the output value of the second amplifier and the optimum gain value determination reference value.
  • the memory M 11 stores an absolute value
  • the memory M 12 stores an optimum gain value determination threshold value ⁇ Vsth.
  • the memory M 13 stores a next correction value NC′ of the count value N.
  • the memory M 14 stores “1” when the paper type is plain paper, and “2” for specialty paper.
  • the memory M 15 stores an optimum gain value NGsp.
  • the memory M 16 stores an overlap detection threshold value Vth.
  • the memory M 17 stores an output value AP 3 of the third amplifier.
  • the memory M 18 stores a count value N ⁇ of the printing press rotation phase detection counter.
  • the memory M 19 stores a printing press rotation phase ⁇ .
  • the memory M 20 stores an overlap detection phase N ⁇ sp.
  • the memory M 21 stores a detection output value AP. The contents stored in the memories M 1 to M 21 will be explained later in association with the description of the overlap detection processing operation.
  • FIG. 8 shows the arrangement of the printing press control apparatus 200 .
  • the printing press control apparatus 200 comprises a CPU 201 , print start switch 202 , print stop switch 203 , overlap detection apparatus reset switch 204 , input device 205 , display device 206 , output device 207 , feeding unit 208 , first printing unit 209 1 to fourth printing unit 209 4 , drive motor driver 210 , drive motor 211 , drive motor rotary encoder 212 , interfaces 213 to 217 , ROM 218 , and RAM 219 .
  • the CPU 101 executes the processing operation in accordance with an overlap detection program stored in the ROM 102 .
  • the CPU 101 Upon receiving an instruction to start the overlap detection program, the CPU 101 sets the count value NRmax corresponding to the maximum output value of the ultrasonic reception sensor in the memory M 1 to 0 ( FIG. 9A : step S 101 ). Next, the CPU outputs “0” to the VCO D/A converter 107 (step S 102 ) so that a driving frequency f from the ultrasonic oscillation circuit 109 to the ultrasonic transmission sensor 110 is set to f 0 . The CPU receives the output value AP 1 (AP 1 0 ) from the first amplifier 112 via the A/D converter 120 and overwrites it in the memory M 2 as the maximum output value AP 1 max (step S 103 ).
  • the CPU 101 sets the count value N in the memory M 3 to “1” (step S 104 ), reads out the count value N from the memory M 3 (step S 105 ), and outputs it to the VCO D/A converter 107 (step S 106 ).
  • the driving frequency f from the ultrasonic oscillation circuit 109 to the ultrasonic transmission sensor 110 is set to f 1 .
  • the CPU 101 receives the output value AP 1 (AP 1 1 ) from the first amplifier 112 at this time via the A/D converter 120 and overwrites it in the memory M 4 (step S 107 ).
  • the CPU reads out the maximum output value AP 1 max (AP 1 0 ) of the ultrasonic reception sensor at that time from the memory M 2 (step S 108 ) and compares it with the output value AP 1 (AP 1 1 ) of the first amplifier 112 in the memory M 4 ( FIG. 9B : step S 109 ). If AP 1 is larger than AP 1 max (YES in step S 109 ), the CPU overwrites AP 1 in the memory M 2 as AP 1 max (step S 110 ). In this case, since AP 1 1 is larger than AP 1 0 , AP 1 max changes to AP 1 1 .
  • the CPU reads out the count value N from the memory M 3 (step S 115 ) and repeats the processing operation in steps S 105 to S 116 until the count value N satisfies N>255 (NO in step S 116 ).
  • the process jumps to step S 113 to repeat the same processing operation without executing steps S 110 , S 111 , and S 112 .
  • the driving frequency f to the ultrasonic transmission sensor 110 changes stepwise from f 0 to f 255 (see FIG. 19A ).
  • the maximum one of the output values AP 1 of the first amplifier 112 obtained in correspondence with the driving frequencies f 0 to f 255 is stored as AP 1 max (see FIG. 19B ).
  • the count value N corresponding to a driving frequency fx upon obtaining the maximum value AP 1 max is stored in the memory M 1 as the count value NRmax corresponding to the maximum output value of the ultrasonic reception sensor.
  • step S 116 the CPU 101 reads out, from the memory M 1 , the count value NRmax corresponding to the maximum output value of the ultrasonic reception sensor (step S 117 ) and writes the readout count value NRmax in the memory M 5 as the optimum driving frequency value Nsp of the ultrasonic transmission sensor (step S 118 ). That is, the CPU decides f Nsp as the optimum driving frequency of the ultrasonic transmission sensor and writes the optimum driving frequency value Nsp corresponding to the optimum driving frequency f Nsp in the memory M 5 .
  • a driving signal is output to the drive motor driver 210 (step S 302 ) to start operating the printing press.
  • a feed start instruction is output to the feeding unit 208 (step S 303 ) to start paper feed to the printing press.
  • a print start signal is transmitted to the overlap detection apparatus 100 (step S 304 ).
  • a print start instruction is output to the printing units 209 1 to 209 4 ( FIG. 10B : step S 307 ).
  • the CPU 101 of the overlap detection apparatus 100 Upon receiving the print start signal from the printing press control apparatus 200 ( FIG. 9C : YES in step S 119 ), the CPU 101 of the overlap detection apparatus 100 reads out the optimum driving frequency value Nsp of the ultrasonic sensor from the memory MS (step S 120 ) and outputs the readout optimum driving frequency value Nsp of the ultrasonic sensor to the VCO D/A converter 107 (step S 121 ).
  • the driving frequency f from the ultrasonic oscillation circuit 109 to the ultrasonic transmission sensor 110 is set to the optimum driving frequency f Nsp .
  • the CPU receives the output value AP 1 from the first amplifier 112 (step S 123 ), reads out the paper presence determination threshold value Vth 1 from the memory M 7 (step S 124 ), and compares the output value AP 1 of the first amplifier 112 with the paper presence determination threshold value Vth 1 (step S 125 ).
  • the CPU 101 repeats the processing in steps S 123 to S 125 .
  • the CPU determines that one fed paper sheet 4 is sandwiched between the ultrasonic transmission sensor 110 and the ultrasonic reception sensor 111 , and writes “128” in the memory M 3 as the count value N ( FIG. 9D : step S 126 ).
  • the CPU also receives the output value AP 2 from the second amplifier 113 via the A/D converter 119 ( FIG. 11B : point t 1 ) and writes it in the memory M 8 (step S 128 ).
  • the CPU reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 129 ), subtracts the output value AP 2 of the second amplifier 113 from the optimum gain value determination reference value Vs to obtain the difference ⁇ Vs between the output value AP 2 of the second amplifier 113 and the optimum gain value determination reference value Vs (step S 130 ), and obtains the absolute value
  • the obtained difference ⁇ Vs is written in the memory M 10 .
  • of the difference is written in the memory M 11 .
  • the CPU 101 reads out the optimum gain value determination threshold value ⁇ Vsth from the memory M 12 (step S 132 ) and compares it with the absolute value
  • step S 134 the CPU 101 reads out the output value AP 2 of the second amplifier 113 at that time from the memory M 8 (step S 134 ), reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 135 ), and compares the output value AP 2 of the second amplifier 113 with the optimum gain value determination reference value Vs (step S 136 ).
  • the CPU also receives the output value AP 2 from the second amplifier 113 via the A/D converter 119 ( FIG. 11B : point t 2 ) and writes it in the memory M 8 (step S 147 ).
  • the CPU reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 148 ), subtracts the output value AP 2 of the second amplifier 113 from the optimum gain value determination reference value Vs to obtain the difference ⁇ Vs between the output value AP 2 of the second amplifier 113 and the optimum gain value determination reference value Vs (step S 149 ), and obtains the absolute value
  • the CPU reads out the optimum gain value determination threshold value ⁇ Vsth from the memory M 12 (step S 151 ) and compares it with the absolute value
  • step S 152 If
  • step S 153 the CPU 101 reads out the output value AP 2 of the second amplifier 113 at that time from the memory M 8 (step S 153 ), reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 154 ), and compares the output value AP 2 of the second amplifier 113 with the optimum gain value determination reference value Vs (step S 155 ).
  • AP 2 ⁇ Vs.
  • the CPU also receives the output value AP 2 from the second amplifier 113 via the A/D converter 119 ( FIG. 11B : point t 3 ) and writes it in the memory M 8 (step S 147 ).
  • the CPU reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 148 ), subtracts the output value AP 2 of the second amplifier 113 from the optimum gain value determination reference value Vs to obtain the difference ⁇ Vs between the output value AP 2 of the second amplifier 113 and the optimum gain value determination reference value Vs (step S 149 ), and obtains the absolute value
  • the CPU reads out the optimum gain value determination threshold value ⁇ Vsth from the memory M 12 (step S 151 ) and compares it with the absolute value
  • step S 152 If
  • step S 171 the CPU 101 determines that the output value AP 2 of the second amplifier 113 is almost equal to the optimum gain value determination reference value Vs (AP 2 ⁇ Vs), and writes “1” representing that the fed paper sheet 4 is plain paper in the memory M 14 (step S 171 ).
  • the CPU reads out the output value AP 2 of the second amplifier 113 from the memory M 8 (step S 174 ), multiplies the readout output value AP 2 of the second amplifier by 0.8 to obtain the overlap detection threshold value Vth, and writes it in the memory M 16 (step S 175 ).
  • the gain GA of the second amplifier 113 is GA 224 ,
  • the CPU also receives the output value AP 2 from the second amplifier 113 via the A/D converter 119 ( FIG. 13B : point t 2 ) and writes it in the memory M 8 (step S 147 ).
  • the CPU reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 148 ), subtracts the output value AP 2 of the second amplifier 113 from the optimum gain value determination reference value Vs to obtain the difference ⁇ Vs between the output value AP 2 of the second amplifier 113 and the optimum gain value determination reference value Vs (step S 149 ), and obtains the absolute value
  • the CPU reads out the optimum gain value determination threshold value ⁇ Vsth from the memory M 12 (step S 151 ) and compares it with the absolute value
  • step S 152 If
  • step S 153 the CPU 101 reads out the output value AP 2 of the second amplifier 113 at that time from the memory M 8 (step S 153 ), reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 154 ), and compares the output value AP 2 of the second amplifier 113 with the optimum gain value determination reference value Vs (step S 155 ).
  • AP 2 >Vs.
  • the CPU also receives the output value AP 2 from the second amplifier 113 via the A/D converter 119 ( FIG. 13B : point t 3 ) and writes it in the memory M 8 (step S 147 ).
  • the CPU reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 148 ), subtracts the output value AP 2 of the second amplifier 113 from the optimum gain value determination reference value Vs to obtain the difference ⁇ Vs between the output value AP 2 of the second amplifier 113 and the optimum gain value determination reference value Vs (step S 149 ), and obtains the absolute value
  • the CPU reads out the optimum gain value determination threshold value ⁇ Vsth from the memory M 12 (step S 151 ) and compares it with the absolute value
  • step S 152 If
  • step S 171 the CPU 101 determines that the output value AP 2 of the second amplifier 113 is almost equal to the optimum gain value determination reference value Vs (YES in step S 152 ), and writes “1” representing that the fed paper sheet 4 is plain paper in the memory M 14 (step S 171 ).
  • the CPU reads out the output value AP 2 of the second amplifier 113 from the memory M 8 (step S 174 ), multiplies the readout output value AP 2 of the second amplifier by 0.8 to obtain the overlap detection threshold value Vth, and writes it in the memory M 16 (step S 175 ).
  • the gain GA of the second amplifier 113 is GA 32 ,
  • step S 165 After the gain GA is set to “GA 1 ”, the correction value NC′ of the count value N in step S 165 ( FIG. 9H ) is 0.5. Since YES in step S 166 , the process advances to step S 167 to set the correction value NC of the count value to 1. If the count value N ⁇ 0 in step S 163 , the CPU transmits an error signal to the printing press control apparatus 200 (step S 169 ).
  • step S 164 the CPU 101 determines that
  • the CPU receives the output value AP 3 from the third amplifier 114 via the A/D converter 118 ( FIG. 15C : point t 2 ) and writes it in the memory M 17 (step S 179 ).
  • the CPU reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 180 ), subtracts the output value AP 3 of the third amplifier 114 from the optimum gain value determination reference value Vs to obtain the difference ⁇ Vs between the output value AP 3 of the third amplifier 114 and the optimum gain value determination reference value Vs (step S 181 ), and obtains the absolute value
  • the obtained difference ⁇ Vs is written in the memory M 10 .
  • of the difference is written in the memory M 11 .
  • the CPU reads out the optimum gain value determination threshold value ⁇ Vsth from the memory M 12 (step S 183 ) and compares it with the absolute value
  • step S 185 the CPU 101 reads out the output value AP 3 of the third amplifier 114 at that time from the memory M 17 (step S 185 ), reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 186 ), and compares the output value AP 3 of the third amplifier 114 with the optimum gain value determination reference value Vs (step S 187 ).
  • the CPU also receives the output value AP 3 from the third amplifier 114 via the A/D converter 118 ( FIG. 15C : point t 3 ) and writes it in the memory M 17 (step S 198 ).
  • the CPU reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 199 ), subtracts the output value AP 3 of the third amplifier 114 from the optimum gain value determination reference value Vs to obtain the difference ⁇ Vs between the output value AP 3 of the third amplifier 114 and the optimum gain value determination reference value Vs (step S 200 ), and obtains the absolute value
  • the CPU reads out the optimum gain value determination threshold value ⁇ Vsth from the memory M 12 (step S 202 ) and compares it with the absolute value
  • step S 204 the CPU 101 reads out the output value AP 3 of the third amplifier 114 at that time from the memory M 17 (step S 204 ), reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 205 ), and compares the output value AP 3 of the third amplifier 114 with the optimum gain value determination reference value Vs (step S 206 ).
  • AP 3 ⁇ Vs.
  • the CPU also receives the output value AP 3 from the third amplifier 114 via the A/D converter 118 ( FIG. 15C : point t 4 ) and writes it in the memory M 17 (step S 198 ).
  • the CPU reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 199 ), subtracts the output value AP 3 of the third amplifier 114 from the optimum gain value determination reference value Vs to obtain the difference ⁇ Vs between the output value AP 3 of the third amplifier 114 and the optimum gain value determination reference value Vs (step S 200 ), and obtains the absolute value
  • the CPU reads out the optimum gain value determination threshold value ⁇ Vsth from the memory M 12 (step S 202 ) and compares it with the absolute value
  • step S 204 If
  • step S 222 the CPU 101 determines that the output value AP 3 of the third amplifier 114 is almost equal to the optimum gain value determination reference value Vs (AP 3 ⁇ Vs), and writes “2” representing that the fed paper sheet 4 is specialty paper in the memory M 14 (step S 222 ).
  • the CPU reads out the output value AP 3 of the third amplifier 114 from the memory M 17 (step S 225 ), multiplies the readout output value AP 3 of the third amplifier by 0.8 to obtain the overlap detection threshold value Vth, and writes it in the memory M 16 (step S 226 ).
  • the gain GA of the second amplifier 113 is GA 224 ,
  • the CPU also receives the output value AP 3 from the third amplifier 114 via the A/D converter 118 ( FIG. 17C : point t 3 ) and writes it in the memory M 17 (step S 198 ).
  • the CPU reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 199 ), subtracts the output value AP 3 of the third amplifier 114 from the optimum gain value determination reference value Vs to obtain the difference ⁇ Vs between the output value AP 3 of the third amplifier 114 and the optimum gain value determination reference value Vs (step S 200 ), and obtains the absolute value
  • the CPU reads out the optimum gain value determination threshold value ⁇ Vsth from the memory M 12 (step S 202 ) and compares it with the absolute value
  • step S 204 If
  • step S 204 the CPU 101 reads out the output value AP 3 of the third amplifier 114 at that time from the memory M 17 (step S 204 ), reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 205 ), and compares the output value AP 3 of the third amplifier 114 with the optimum gain value determination reference value Vs (step S 206 ).
  • AP 3 >Vs.
  • the CPU also receives the output value AP 3 from the third amplifier 114 via the A/D converter 118 ( FIG. 17C : point t 4 ) and writes it in the memory M 17 (step S 198 ).
  • the CPU reads out the optimum gain value determination reference value Vs from the memory M 9 (step S 199 ), subtracts the output value AP 3 of the third amplifier 114 from the optimum gain value determination reference value Vs to obtain the difference ⁇ Vs between the output value AP 3 of the third amplifier 114 and the optimum gain value determination reference value Vs (step S 200 ), and obtains the absolute value
  • the CPU reads out the optimum gain value determination threshold value ⁇ Vsth from the memory M 12 (step S 202 ) and compares it with the absolute value
  • step S 204 If
  • step S 222 the CPU 101 determines that the output value AP 3 of the third amplifier 114 is almost equal to the optimum gain value determination reference value Vs (YES in step S 203 ), and writes “2” representing that the fed paper sheet 4 is specialty paper in the memory M 14 (step S 222 ).
  • the CPU reads out the output value AP 3 of the third amplifier 114 from the memory M 17 (step S 225 ), multiplies the readout output value AP 3 of the third amplifier by 0.8 to obtain the overlap detection threshold value Vth, and writes it in the memory M 16 (step S 226 ).
  • the gain GA of the second amplifier 113 is GA 32 ,
  • step S 217 After the gain GA is set to “GA 1 ”, the correction value NC′ of the count value N in step S 217 ( FIG. 9M ) is 0.5. Since YES in step S 217 , the process advances to step S 218 to set the correction value NC of the count value to 1. If the count value N ⁇ 0 in step S 214 , the CPU transmits an error signal to the printing press control apparatus 200 (step S 220 ).
  • the CPU 101 transmits an error signal to the printing press control apparatus 200 , like when the count value N ⁇ 0 (step S 220 ).
  • the CPU 201 of the printing press control apparatus 200 Upon receiving the error signal from the overlap detection apparatus 100 ( FIG. 10A : YES in step S 305 ), the CPU 201 of the printing press control apparatus 200 outputs a feed stop instruction to the feeding unit 208 ( FIG. 10C : step S 316 ) to stop paper feed from the feeding unit 208 to the printing press.
  • the CPU also outputs a print stop instruction to the printing units 209 1 to 209 4 (step S 317 ) to cause them to stop printing on paper sheets.
  • the CPU also outputs a driving stop signal to the drive motor driver 210 (step S 318 ) to stop the printing press.
  • step S 319 When the overlap detection apparatus reset switch 204 is turned on (YES in step S 319 ), the CPU 201 of the printing press control apparatus 200 transmits a reset signal to the overlap detection apparatus 100 (step S 320 ). When the print start switch 202 is turned on (YES in step S 321 ), the process returns to step S 302 ( FIG. 10A ) to resume the operation of the printing press.
  • step S 221 Upon receiving the reset signal from the printing press control apparatus 200 ( FIG. 9H : YES in step S 170 , FIG. 9M : YES in step S 221 ), the CPU 101 of the overlap detection apparatus 100 returns to step S 101 ( FIG. 9A ) to execute the above-described series of processing operations again.
  • the CPU 101 of the overlap detection apparatus 100 After executing the process in steps S 171 to S 175 ( FIG. 9F ) or the process in steps S 222 to S 226 ( FIG. 9K ), i.e., deciding the overlap detection monitor output and gain, the CPU 101 of the overlap detection apparatus 100 reads out the optimum driving frequency value Nsp of the ultrasonic transmission sensor from the memory M 5 ( FIG. 9N : step S 227 ) and outputs it to the VCO D/A converter 107 (step S 228 ).
  • the driving frequency f from the ultrasonic oscillation circuit 109 to the ultrasonic transmission sensor 110 is set to fNsp.
  • the CPU 101 reads out the optimum gain value NGsp from the memory M 15 (step S 229 ) and outputs it to the D/A converter 115 for second amplifier gain adjustment (step S 230 ).
  • a gain GA NGsp is set in the second amplifier 113 as the overlap detection gain GAsp.
  • the CPU 101 reads out the count value N ⁇ from the printing press rotation phase detection counter 116 (step S 231 ), obtains the printing press rotation phase ⁇ based on the readout count value N ⁇ (step S 232 ), reads out an overlap detection phase ⁇ sp from the memory M 20 (step S 233 ), and compares the printing press rotation phase ⁇ with the overlap detection phase ⁇ sp (step S 234 )
  • steps S 231 to S 234 are repeated, and if the printing press rotation phase ⁇ equals the overlap detection phase ⁇ sp (YES in step S 234 ), the CPU reads out the storage contents from the memory M 14 ( FIG. 9O : step S 235 ). If the storage contents of the memory M 14 represents “1” (plain paper) (YES in step S 236 ), the CPU receives the output value AP 2 from the second amplifier 113 via the A/D converter 119 and writes it in the memory M 21 as the detection output value AP (step S 237 ).
  • the CPU receives the output value AP 3 from the third amplifier 114 via the A/D converter 118 and writes it in the memory M 21 as the detection output value AP (step S 238 ).
  • the CPU reads out the detection output value AP from the memory M 21 (step S 239 ) and also reads out an overlap detection threshold value Vth stored in the memory M 16 (step S 240 ). If the detection output value AP ⁇ Vth (YES in step S 241 ), the CPU transmits an overlap detection signal to the printing press control apparatus 200 (step S 243 ). If the detection output value AP ⁇ Vth does not hold (NO in step S 241 ), the process returns from step S 242 to step S 231 ( FIG. 9N ) to repeat the same processing operation as described above.
  • step S 242 If a print stop signal from the printing press control apparatus 200 is confirmed in step S 242 , the process returns to step S 119 ( FIG. 9C ) to wait for a print start signal from the printing press control apparatus 200 .
  • the CPU 201 of the printing press control apparatus 200 Upon receiving the overlap detection signal from the overlap detection apparatus 100 ( FIG. 10B : YES in step S 306 , YES in step S 308 ), the CPU 201 of the printing press control apparatus 200 outputs a feed stop instruction to the feeding unit 208 (step S 314 ) to stop paper feed from the feeding unit 208 to the printing press.
  • the CPU also outputs a print stop instruction to the printing units 209 1 to 209 4 (step S 315 ) to cause them to stop printing on paper sheets.
  • the CPU also outputs a driving stop signal to the drive motor driver 210 (step S 313 ) to stop the printing press.
  • step S 308 The overlap detection signal confirmation in step S 308 is repeatedly executed after the output of the print start instruction to the printing units 209 1 to 209 4 (step S 307 ). If the print stop switch 203 is turned on during this repetitive execution (YES in step S 309 ), the CPU 201 of the printing press control apparatus 200 outputs a feed stop instruction to the feeding unit 208 (step S 310 ), transmits a print stop signal to the overlap detection apparatus 100 (step S 311 ), outputs a print stop instruction to the printing units 209 1 to 209 4 (step S 312 ), and outputs a driving stop signal to the drive motor driver 210 (step S 313 ).
  • FIG. 20 shows functional blocks implemented by the CPU which operates in accordance with the overlap detection program.
  • the CPU 101 implements at least an overlap detection monitor output & amplification factor decision unit 130 and an overlap detection unit 134 .
  • the overlap detection monitor output & amplification factor decision unit 130 comprises an amplification factor control unit 131 , first overlap detection monitor output & amplification factor decision unit 132 , and second overlap detection monitor output & amplification factor decision unit 133 .
  • the amplification factor control unit 131 controls the gain GA of the second amplifier 113 .
  • the amplification factor control unit 131 performs the processes in, e.g., steps S 126 and S 127 , S 137 to S 146 , S 156 to S 168 , S 177 and S 178 , S 188 to S 197 , and S 207 to S 219 .
  • the amplification factor control unit 131 comprises a change width control unit 131 A and a change direction control unit 131 B.
  • the change width control unit 131 A repeatedly changes the gain GA of the second amplifier 113 while reducing the change width.
  • the change width control unit 131 A performs the processes in, e.g., steps S 143 and S 144 , S 156 to S 161 , S 165 to S 168 , S 194 and S 195 , S 207 to S 212 , and S 216 to S 219 .
  • the change direction control unit 131 B changes the gain GA of the second amplifier 113 in a direction different from that of the previous time. For example, when AP 2 ⁇ Vs has changed to AP 2 >Vs, the change direction control unit 131 B changes the direction of the gain GA from an increasing direction to a decreasing direction.
  • the change direction control unit 131 B performs the processes in, e.g., steps S 155 to S 161 , and S 206 to S 212 .
  • the first overlap detection monitor output & amplification factor decision unit 132 comprises a first equivalence determination unit 132 A, first overlap detection monitor output decision unit 132 B, and first overlap detection amplification factor decision unit 132 C.
  • the first equivalence determination unit 132 A determines whether the output value AP 2 of the second amplifier 113 is almost equal to the optimum gain value determination reference value Vs. If the absolute value of the difference between the output value AP 2 of the second amplifier 113 and the optimum gain value determination reference value Vs is smaller than the optimum gain value determination threshold value (first threshold value) ⁇ Vsth, the first equivalence determination unit 132 A determines that the output value AP 2 of the second amplifier 113 is almost equal to the optimum gain value determination reference value Vs.
  • the first equivalence determination unit 132 A performs the processes in, e.g., steps S 128 to S 133 , and S 147 to S 152 .
  • the first overlap detection monitor output decision unit 132 B decides the output from the second amplifier 113 as the overlap detection monitor output.
  • the first overlap detection monitor output decision unit 132 B performs the process in, e.g., step S 171 .
  • the first overlap detection amplification factor decision unit 132 C decides, as the overlap detection gain GAsp, the gain GA of the second amplifier 113 when the output value AP 2 of the second amplifier 113 has become almost equal to the optimum gain value determination reference value Vs.
  • the first overlap detection amplification factor decision unit 132 C performs the processes in, e.g., steps S 172 and S 173 .
  • the second overlap detection monitor output & amplification factor decision unit 133 comprises a second equivalence determination unit 133 A, second overlap detection monitor output decision unit 133 B, and second overlap detection amplification factor decision unit 133 C.
  • the second equivalence determination unit 133 A determines whether the output value AP 3 of the third amplifier 114 is almost equal to the optimum gain value determination reference value Vs. If the absolute value of the difference between the output value AP 3 of the third amplifier 114 and the optimum gain value determination reference value Vs is smaller than the optimum gain value determination threshold value (second threshold value) ⁇ Vsth, the second equivalence determination unit 133 A determines that the output value AP 3 of the third amplifier 114 is almost equal to the optimum gain value determination reference value Vs.
  • the second equivalence determination unit 133 A performs the processes in, e.g., steps S 179 to S 184 , and S 198 to S 203 .
  • the second overlap detection monitor output decision unit 133 B decides the output from the third amplifier 114 as the overlap detection monitor output.
  • the second overlap detection monitor output decision unit 133 B performs the process in, e.g., step S 222 .
  • the second overlap detection amplification factor decision unit 133 C decides, as the overlap detection gain GAsp, the gain GA of the second amplifier 113 when the output value AP 3 of the third amplifier 114 has become almost equal to the optimum gain value determination reference value Vs.
  • the second overlap detection amplification factor decision unit 133 C performs the processes in, e.g., steps S 223 and S 224 .
  • the overlap detection unit 134 Based on the output from the second or third amplifier 113 or 114 decided as the overlap detection monitor output by the first or second overlap detection monitor output decision unit 132 B or 133 B, the overlap detection unit 134 detects overlap of the fed paper sheets 4 which pass between the ultrasonic transmission sensor 110 and the ultrasonic reception sensor 111 .
  • the overlap detection unit 134 performs the processes in, e.g., steps S 227 to S 243 .
  • the amplification factor control unit 131 sets, in the second amplifier 113 , the overlap detection gain GAsp decided by the first or second overlap detection amplification factor decision unit 132 C or 133 C.
  • the amplification factor of the second amplifier is changed while sandwiching one sheet between the ultrasonic transmitter and the ultrasonic receiver.
  • the output of the second amplifier is decided as the sheet overlap detection monitor output if the output value from the second amplifier is recognized to be almost equal to the first set value defined in advance. For example, if the amplification factor GA of the second amplifier is raised stepwise from GA 0 to GA 255 , and the output value AP 2 from the second amplifier has become almost equal to the first set value (V 2 s ) halfway (AP 2 ⁇ V 2 s ), the output from the second amplifier is decided as the overlap detection monitor output.
  • the output from the third amplifier is decided as the overlap detection monitor output.
  • the amplification factor GA of the second amplifier is raised stepwise from GA 0 to GA 255 , and AP 2 ⁇ V 2 s does not hold, the amplification factor GA of the second amplifier is raised again stepwise from GA 0 to GA 255 . If the output value AP 3 from the third amplifier becomes almost equal to the second set value (V 3 s ) halfway (AP 3 ⁇ V 3 s ), the output from the third amplifier is decided as the overlap detection monitor output.
  • the amplification factor of the second amplifier at that time is decided as the sheet overlap detection amplification factor.
  • the amplification factor of the second amplifier at that time is decided as the overlap detection amplification factor.
  • the amplification factor GA need not always be raised stepwise from GA 0 to GA 255 .
  • the amplification factor GA is set to GA 128 first. If the output from the second amplifier at that time is smaller than the first set value, the amplification factor GA is raised to GA 192 .
  • the amplification factor GA may be narrowed down in this way until the output value from the second amplifier almost equals the first set value.
  • the output from the second amplifier and that from the third amplifier are stored while raising the amplification factor GA of the second amplifier stepwise from GA 0 to GA 255 . Then, the output value from the second amplifier and that from the third amplifier corresponding to each of the amplification factors GA 0 to GA 255 are observed. If the output value from the second amplifier is recognized to be almost equal to the first set value V 2 s, the output from the second amplifier is decided as the sheet overlap detection monitor output. If the output value from the second amplifier is not recognized to be almost equal to the first set value V 2 s, but the output value from the third amplifier is recognized to be almost equal to the second set value V 3 s, the output from the third amplifier is decided as the sheet overlap detection monitor output. This obviates changing the amplification factor GA of the second amplifier again and speeds up the processing.
  • the first set value and the second set value may be different or the same.
  • the first threshold value and the second threshold value may also be different or the same.
  • the sheets as the overlap detection target are not limited to the fed paper sheets to the printing press.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Controlling Sheets Or Webs (AREA)
  • Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
US12/284,005 2007-09-19 2008-09-17 Sheet overlap detection apparatus and sheet overlap detection method Abandoned US20090072475A1 (en)

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JP242919/2007 2007-09-19
JP2007242919A JP2009073603A (ja) 2007-09-19 2007-09-19 シート状物の重複検出装置および重複検出方法

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JP5724469B2 (ja) * 2011-03-08 2015-05-27 株式会社リコー 重送検知装置、画像形成装置、及び重送検知プログラム
EP2769949B1 (de) * 2013-02-21 2018-05-30 Pepperl & Fuchs GmbH Verfahren zum messtechnischen Unterscheiden von Materialbereichen eines blatt-, bahn- oder bogenartigen Materials sowie Vorrichtung hierzu
JP6337537B2 (ja) * 2014-03-17 2018-06-06 株式会社リコー 用紙搬送装置、画像形成装置及び重送判定方法
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