US3780310A - Apparatus for detecting unprepared postage stamps - Google Patents

Apparatus for detecting unprepared postage stamps Download PDF

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Publication number
US3780310A
US3780310A US00236619A US3780310DA US3780310A US 3780310 A US3780310 A US 3780310A US 00236619 A US00236619 A US 00236619A US 3780310D A US3780310D A US 3780310DA US 3780310 A US3780310 A US 3780310A
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Prior art keywords
serrations
photoelectric
stamp
sensing means
light
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US00236619A
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English (en)
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H Hudler
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
    • B07C3/00—Sorting according to destination
    • B07C3/10—Apparatus characterised by the means used for detection ofthe destination
    • B07C3/14—Apparatus characterised by the means used for detection ofthe destination using light-responsive detecting means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
    • B07C1/00—Measures preceding sorting according to destination
    • B07C1/20—Sorting according to orientation, e.g. according to position of stamp

Definitions

  • ABSTRACT There is disclosed an optical arrangement for detecting regular, non-specially-prepared postage stamps for machines which accordingly face or orient the articles for automatic sorting. Detection is limited to the serrated edges common to all existing stamps, which serrations may easily be made into a code.
  • a light source is arranged to impinge radiation at an acute angle relative to the direction of document travel. Thereby the sides of the serrations parallel to this direction are highly illuminated.
  • a photoelectric sensor receives the train of light pulses emitted by the sides of the stamp serrations, which are fed to an amplifier and on to a pulse counting circuit, which serves to operate a deflector.
  • the facing of the letters by machine involves the searching for and detection of the postage stamps.
  • the optical methods presently used to identify postage stamps do not give satisfactory results.
  • postage stamps have been prepared by being provided with detectable marks.
  • Various methods have been developed for this purpose. Of these methods, one of the most reliable ones involves the use of luminescent post age stamps.
  • the paper of the postage stamps is impregnated or coated with fluorescent or phosphorescent dyestuff so that the stamps can be relatively easily detected when irradiated with ultraviolet light (quartz lamp) and simple indicating methods can be employed. In this method, the percentage of errors is low (about 1 percent).
  • the finished postage stamp is provided with a luminescent coating, or specific spectral colors are used in the stamp picture and can be screened out with the aid of special filters and indicated.
  • the invention provides an apparatus for identifying normal, serrated, unprepared postage stamps on letters by machine, which apparatus comprises a light source, which illuminates at a small angle the letters moved in a given direction, and a photoelectric sensor, and is characterized in that the light source is arranged so that the light rays include an acute angle with the direction of travel and the stamps are thus laterally illuminated with grazing light in such a manner that the sides of the serrations on the stamp sides which are parallel to the direction of travel are highly illuminated, and the pho toelectric sensor, which receives a train of light pulses emitted by the sides of the serrations of the passing stamps, is connected to a threshold amplifier, which has an optimum gain in a range which is adjustable to include the frequency of the serrations passing the sensor, whereas the output of the amplifier is connected by a timer or by a pulse-counting circuit to a known switch, which serves, e.g., to operate a deflector for selecting a route for each letter.
  • the photoelectric sensor consists, in accordance: with the invention, of one or more photoelectric cells provided with a slit, or of one or more photoelectric cells provided with an optical system which comprises at least two cylindrical lenses having longitudinal axes at an angle of to each other.
  • a plurality of photoelectric cells are provided, if desired, in combination with a selector circuit which onsures that only that amplifier channel which carries the useful signal is used to operate the switch.
  • the transient time of the selective amplifier is selected so that an audio-frequency signal voltage which is sufficient to initiate the switching operation will not be generated until the scanning operation has been performed for a time which is approximately one-half of the time for a stamp to pass.
  • An imporatant feature of the invention resides in that strong grazing light is used for scanning so that the apices and sides of the serrations are particularly brightly illuminated. This optimum effect can easily be obtained if the light source is adjustable and the photoelectric arrangement is rotatable and pivotally movable.
  • the principle underlying the invention affords the advantage that only the postage stamps, and of these only the serrations, are sensed, whereas there is no photoelectric respouse to disturbing imprints, marks and the like.
  • the stamps are provided with serrations differing in pitch, in dependence on the value of the stamps, the provision of a plurality of selective amplifiers, which are tuned to suitable frequencies, will enable a check as to the value of the postage stamps or a sorting for other considerations.
  • FIG. 1 is a side elevation showing the apparatus according to the invention
  • FIGS. 2a, 2b and 2c show different embodiments of the photoelectric sensor
  • FIG. 3 shows the limits of the area in which a postage stamp should be stuck on a letter
  • FIG. 4 shows how a plurality of photoelectric sensing units may be used to scan a wide strip
  • FIGS. 5a, 5b and 5c represent the transients of the selective amplifier in response to different signals and FIG. 6 illustrates the most desirable adjustment of the photoelectric sensor.
  • the overall arrangement comprises a belt conveyor 1, by which the letter 2, on which a postage stamp has been stuck, is moved at a constant velocity v under the photoelectric sensor 4.
  • the light source 3 must illuminate the letter and the stamp by strongly grazing light so that only the uneven portions of the surfac of the letter, particularly the stamp with its serrations, are scanned.
  • the photoelectric sensor In response to the scanning of the serrations, the photoelectric sensor generates an audiofrequency pulse train, which is amplified by a selective amplifier 5 and, when a certain threshold value is exceeded, the amplified pulse train is delivered to a timer 6 or to a pulse-counting circuit 7.
  • the scanning may be accomplished in the simplest case by means of a photoelectric cell 9 and a slit 10, which has a small width, e.g., of 0.5 millimeter, and a longitudinal axis extending parallel to the illuminated sides of the serrations.
  • the photoelectric sensor must be disposed very close to the postage stamp so that the sensor can receive a sufficiently large amount of reflected light from the serrations 11. For this reason, provision must be made in connection with the conveyor to ensure that that surface of the letter which is to be scanned is always at the same distance from the photoelectric sensor, regardless of the thickness of the letter. This disadvantage may be avoided by the provision of an optical system between the postage stamp and the photoelectric cell (FIGS.
  • This optical system consists of at least tow cylindrical two one of which (14), forms on the photoelectrical cell 9 an image corresponding to the scanning width (one serration of the postage stamp) whereas the second lens (13) has a longitudinal axis at an angle of 90 to that of the first lens and results in a reduction so that an image correspnding to the width of the scanning strip is formed on the photoelectric cell.
  • the longitudinal axes of the cylindrical lenses are, respectively, parallel and at right angles to the illuminated sides of the serrations.
  • FIGS. 2b and 20 show the light pahts in two section planes which extend through the optical axis at an angle of 90 to each other.
  • An aperture plate 12 disposed in front of the photoelectric cell cooperates with the cylindrical lens system like a slit in conjunction with a normal optical system comprising spherical lenses.
  • the postage stamp should be stuck in an area having dimensions L 74 millimeters and B 40 millimeters at the upper right corner of the letter, as is shown in FIG. 3
  • the photoelectric sensor must cover a strip having a width H of approximately 15 millimeters. This requirement cannot easily be met with a single photoelectric cell. It is more desirable to provide a plurality of photoelectric cells in an arrangement as shown in FIG. 4. In view of their overall dimensions, the photoelectric sensing units 15 are staggered. The resulting scanning time differences are insignificant for the detecting operation.
  • the spacing d of the photoelectric cells in the direction of travel is an integral multiple of the pitch of the serrations to be scanned.
  • the outputs of the photoelectric cells are connected by the amplifier channels 16 to a selector circuit 17, such as an OR gate.
  • This selector circuit connects only that amplifier channel to the switch 8 which carries a signal in response to the scanning of a postage stamp. As a result, any interference signals in the other channels are not added but entirely eliminated.
  • the pulse train received by the selective amplifier will have a frequency f 2500/ l .4 I785 Hz.
  • the voltage waveform at the output of the selective amplifier is represented in FIG. 5a and determined by the transient response of this amplifier.
  • the selected transient time T is about one-half of the scanning time T (t 5 milliseconds).
  • the amplifier may have a bandwidth B which is approximately l/T 200 Hz.
  • the selective amplifier has a Q factor which is equal to 1785/200 9.
  • the switch 8 responds. This requirement may be met by a timer, which comprises a rectifier for the audio-frequency output pulses and a variable integrating resistance-capacitance circuit, or by a circuit 7, which at the time when the threshold voltage has been reached begins to count a presettable number of output pulses and only thereafter operates the switch 8. It is apparent from FIG.
  • FIG. 5c shows that short interference pulses which are very strong will reach the point A but will not reach the point B so that the switch will not respond in this case too. For this reason, the edges of the letters and the uneven portions of the paper are not indicated because they result in signals which have a duration which is shorter than the scanning time of a postage stamp or have a frequency which differs from the audiofrequency of the voltage waveform generated by the serrations.
  • the function of the apparatus according to the invention for the detection of postage stamps depends highly on the illuminating device.
  • the light source is adjustable so that the angle of incidence of the light rays on the plane of the letter or the angle included by the light rays and the direction of travel can be adjusted.
  • the photoelectric sensor is also rotatable about its optical axis. It is apparent in FIG. 6 that the illuminating device L can be rotated through about 30 opposite to the direction of travel F to provide for a particularly bright illumination of the sides of the serrations and a generation of the strongest light pulses. In this case, the photoelectric sensor 18 must be rotated accordingly. Because the strongest reflection from the illuminated serrations will not be at right angles to the plane of the letter, the angle between the optical axis of the photoelectric sensor and the plane of travel should also be adjustable.
  • Apparatus for detecting normal, serrated, unprepared postage stamps on documents moving in a given direction comprising light source means arranged for emitting a single beam of light radiation obliquely directed at an acute angle along the direction of travel of the documents and highly illuminating the sides of the serrations only which are associated to a side of the stamps which is substantially parallel to the direction of travel of the documents, photoelectric sensing means stationarily arranged relative to the moving documents for receiving the light emitted by said sides of said serrations, which received light is in the form of a train of pulses corresponding to the serrated stamp parallel edges moving relative to the light source beamed radiation, threshold amplifying means coupled to said sensing means, said amplifying means being arranged to have an optimum gain.
  • first means coupled to said amplifying means for receiving the output of the latter and deriving therefrom a control output signal which characterizes the positional orientation of the stamp on its associated document.
  • said photoelectric sensing means includes at least one photoelectric cell provided with a slit having a longitudinal axis which is parallel to the illuminated sides of the serrations.
  • said photoelectric sensing means includes at least one photoelectric cell directed to receive said light pulse train, a pair of cylindrical lenses having longitudinal axes which are arranged at an angle of to each other and extend, respectively, parallel and at right angles to the illuminated sides of the serrations, and an aperture plate disposed proximate said photoelectric cell.
  • said photoelectric sensing means includes a plurality of photoelectric cells arranged in a row, said cells having in the direction of travel a predetermined spacing (d) from one another which is an integral multiple of the pitch of the stamp serrations, and further including se lective amplifier means coupled to said plurality of photoelectric cells and having a plurality of amplifier channels, and selector circuit means coupled to said so lector amplifier means for connecting only that amplifier channel which carries the useful output to said first means.
  • said threshold amplifying means is designed such that the transit time thereof is substantially one-half of the time for a moving stamp to pass said photoelectric sensing means.
  • said first means is comprised of a timer arrangement which includes a rectifier and an integrating resistancecapacitance circuit for initiating a controlled output only when a received output from said amplifying means, as derived from an input to the latter which is sufficient for an initiation, has been maintained for a predetermined adjustable time.
  • said first means is comprised of a pulse counting circuit for initiating a controlled output when the photoelectric sensing has resulted in the generation of a predeterminable adjustable number of pulses after the threshold voltage of said amplifying means has been reached.

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  • Sorting Of Articles (AREA)
  • Devices For Checking Fares Or Tickets At Control Points (AREA)
  • Length Measuring Devices By Optical Means (AREA)
US00236619A 1971-03-30 1972-03-21 Apparatus for detecting unprepared postage stamps Expired - Lifetime US3780310A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT269171A AT306412B (de) 1971-03-30 1971-03-30 Vorrichtung zur maschinellen Erkennung nichtpräparierter Briefmarken

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US3780310A true US3780310A (en) 1973-12-18

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US (1) US3780310A (de)
AT (1) AT306412B (de)
BE (1) BE781441A (de)
DE (1) DE2215140C3 (de)
GB (1) GB1355781A (de)
IT (1) IT950721B (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4281243A (en) * 1978-06-06 1981-07-28 Heinz Hudler Apparatus for detecting postage stamps on envelopes
EP0312980A2 (de) * 1987-10-20 1989-04-26 EASTMAN KODAK COMPANY (a New Jersey corporation) Vorrichtung zum Erzeugen von Randdetektionssignalen, um ein Adressenelement auf einem Poststück zu lokalisieren
JPH01131968A (ja) * 1987-11-17 1989-05-24 Nec Corp 切手検知装置
US5122967A (en) * 1988-12-30 1992-06-16 Alcatel Business Systems Limited Postage stamp and dispensing system therefor
GB2253903A (en) * 1991-03-13 1992-09-23 American Res Corp Virginia Reflective optical fabric seam detector
US20040073523A1 (en) * 2002-10-15 2004-04-15 Nec Corporation Mail processing apparatus
US20130057853A1 (en) * 2011-08-31 2013-03-07 Claudio Garcia Rubio Photoelectric meter for stamps perforations

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4222908C2 (de) * 1992-07-11 1994-11-17 Licentia Gmbh Verfahren zur Lokalisierung von Adreßbereichen auf Postgut
AT501375B1 (de) * 2005-01-27 2007-04-15 Oelzant Helmuth Ing Briefmarkenerkennungsvorrichtung

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2908825A (en) * 1956-12-10 1959-10-13 Midwest Automatic Control Co Photoelectric counter
US2936886A (en) * 1954-10-05 1960-05-17 Reed Res Inc Stamp sensing letter sorter
US3313944A (en) * 1963-01-14 1967-04-11 Molins Organisation Ltd Gauging apparatus including an electronic-optical scanner
US3414732A (en) * 1965-10-19 1968-12-03 Milgo Electronic Corp Counter for folded paper objects
US3488511A (en) * 1966-10-25 1970-01-06 Tokyo Shibaura Electric Co Automatic identifying apparatus of postage stamp indications
US3634012A (en) * 1969-04-16 1972-01-11 Rudolf Mustert Method and apparatus for examining intaglio printing

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2936886A (en) * 1954-10-05 1960-05-17 Reed Res Inc Stamp sensing letter sorter
US2908825A (en) * 1956-12-10 1959-10-13 Midwest Automatic Control Co Photoelectric counter
US3313944A (en) * 1963-01-14 1967-04-11 Molins Organisation Ltd Gauging apparatus including an electronic-optical scanner
US3414732A (en) * 1965-10-19 1968-12-03 Milgo Electronic Corp Counter for folded paper objects
US3488511A (en) * 1966-10-25 1970-01-06 Tokyo Shibaura Electric Co Automatic identifying apparatus of postage stamp indications
US3634012A (en) * 1969-04-16 1972-01-11 Rudolf Mustert Method and apparatus for examining intaglio printing

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4281243A (en) * 1978-06-06 1981-07-28 Heinz Hudler Apparatus for detecting postage stamps on envelopes
EP0312980A2 (de) * 1987-10-20 1989-04-26 EASTMAN KODAK COMPANY (a New Jersey corporation) Vorrichtung zum Erzeugen von Randdetektionssignalen, um ein Adressenelement auf einem Poststück zu lokalisieren
EP0312980A3 (de) * 1987-10-20 1990-02-14 EASTMAN KODAK COMPANY (a New Jersey corporation) Vorrichtung zum Erzeugen von Randdetektionssignalen, um ein Adressenelement auf einem Poststück zu lokalisieren
JPH01131968A (ja) * 1987-11-17 1989-05-24 Nec Corp 切手検知装置
US5122967A (en) * 1988-12-30 1992-06-16 Alcatel Business Systems Limited Postage stamp and dispensing system therefor
GB2253903A (en) * 1991-03-13 1992-09-23 American Res Corp Virginia Reflective optical fabric seam detector
GB2253903B (en) * 1991-03-13 1995-01-04 American Res Corp Virginia Optical imaging system for fabric seam detection
US20040073523A1 (en) * 2002-10-15 2004-04-15 Nec Corporation Mail processing apparatus
US20130057853A1 (en) * 2011-08-31 2013-03-07 Claudio Garcia Rubio Photoelectric meter for stamps perforations
US8717554B2 (en) * 2011-08-31 2014-05-06 Claudio GARCIA RUBIO Photoelectric meter for stamps perforations

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Publication number Publication date
DE2215140B2 (de) 1974-12-05
GB1355781A (en) 1974-06-05
DE2215140C3 (de) 1975-08-28
BE781441A (nl) 1972-10-02
AT306412B (de) 1973-04-10
IT950721B (it) 1973-06-20
DE2215140A1 (de) 1972-10-05

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