US3571612A - Safety device for an exposure lamp in a reproduction apparatus - Google Patents

Safety device for an exposure lamp in a reproduction apparatus Download PDF

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Publication number
US3571612A
US3571612A US779446A US3571612DA US3571612A US 3571612 A US3571612 A US 3571612A US 779446 A US779446 A US 779446A US 3571612D A US3571612D A US 3571612DA US 3571612 A US3571612 A US 3571612A
Authority
US
United States
Prior art keywords
safety device
safety
exposure
relay contact
relay
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US779446A
Other languages
English (en)
Inventor
Takeshi Ukai
Shoji Sakai
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Application granted granted Critical
Publication of US3571612A publication Critical patent/US3571612A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/36—Controlling
    • H05B41/38—Controlling the intensity of light
    • H05B41/39—Controlling the intensity of light continuously
    • H05B41/392—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/04—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
    • G03G15/04036—Details of illuminating systems, e.g. lamps, reflectors
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/04—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
    • G03G15/043—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material with means for controlling illumination or exposure

Definitions

  • ABSTRACT A safety device wherein an exposure lamp is put 307/1413 out without failure even in the case where the exposure lamp 307/94, 315/241 Witching-off circuit is kept on because of some trouble in the s 1101b 3/34- after finishing an exposure.
  • the present invention relates to a reproduction apparatus, and more specifically, to a safety device for an exposure lamp in an electrophotographic reproduction apparatus.
  • An exposure lamp for an elctrophotographic reproduction apparatus is lighted by pushing an operation button, and put out after the finish of an exposure in a normal state.
  • the reproduction apparatus becomes unusable, and moreover, it results in the waste of electric power and a possible outbreak of fire.
  • the invention provides a safety device which switches off exposure lamp without failure in the case where the exposure lamp continues to light after the finish of an exposure because of some trouble in the switching-off circuit.
  • FIG. denotes a circuit indicating an embodiment of the safety device made in accordance with the invention.
  • an exposure lamp 2 and a relay contact 4 mounted in a relay coil 3 are connected in series to the main circuit closed through a switch 1.
  • NC denotes a normally closed contact at 3b
  • NO denotes a normally opened contact at Sat.
  • An exposure control means 5 completes the circuit in accordance with an external exposure signal and energizes the relay coil.
  • a safety contact 6 in accordance with the present invention, which is mounted to a relay coil 7.
  • a switching transistor 6 is connected in series to the relay coil 7.
  • a switching transistor 6 is connected in series to the relay coil 7.
  • a discharge resistor 9, a charging current control resistor 10 and a charge and discharge condenser 11 are connected to the base side of the transistor 8.
  • the reference number 12 denotes a diode for preventing reverse voltage
  • 13 denotes a Zener diode and resistor for constant voltage
  • 14 denotes a rectitier means.
  • the relay coil 3 when the relay coil 3 is energized, the normally closed contact of the relay 4 is opened and thereby the circuit for charging the charge and discharge condenser 11 is opened. Said condenser 11 then begins to discharge through the discharge resistor 9 and the switching transistor 8. After a predetermined time, when this discharge current, that is, the current from the base of the transistor 8 decreases to a value less than a predetermined one, the collector current also decreases and the energization of the relay coil is stopped.
  • the time constants of the condenser 11 and the resistor 9 are selected so that an external exposure release signal may be given to the exposure control means 5 earlier than the contact 6 is opened through the deenergization of the relay coil 7.
  • the contact 6 is operated through the relay coil 7 in order to stop the energization of the relay coil 3, the circuit of the exposure lamp 2 is opened, and the lamp is switched off.
  • the safety device of the invention even if the switching-off circuit of the exposure lamp becomes inoperable, the lamp is reliably switched off. So the normal function of the reproduction apparatus is maintained, and the waste of electric energy and the possible outbreak of fire are prevented. Moreover, since the charging circuit of the safety device of the present invention is opened directly through the on-off relay for the exposure lamp, the construction of the present invention is relatively simple and the operation thereof is reliable.
  • a safety device for an exposure lamp in a reproduction apparatus comprising a relay coil and a relay contact adapted to be electrically coupled with said exposure lamp, said relay contact including normally open and normally closed terminals, exposure control means electrically coupled with said relay coil and adapted for being electrically coupled with an external power source, a safety relay coil and a safety relay contact electrically coupled with said exposure control means, a switching transistor electrically coupled with said safety relay coil and said safety relay contact, and a condenser electrically coupled with said switching transistor and said safety relay contact.
  • a safety device as claimed in claim 4 including a discharge resistor interconnecting said condenser with the base of said transistor.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)
  • Light Sources And Details Of Projection-Printing Devices (AREA)
  • Projection-Type Copiers In General (AREA)
  • Combination Of More Than One Step In Electrophotography (AREA)
US779446A 1967-12-20 1968-11-27 Safety device for an exposure lamp in a reproduction apparatus Expired - Lifetime US3571612A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8118367 1967-12-20

Publications (1)

Publication Number Publication Date
US3571612A true US3571612A (en) 1971-03-23

Family

ID=13739341

Family Applications (1)

Application Number Title Priority Date Filing Date
US779446A Expired - Lifetime US3571612A (en) 1967-12-20 1968-11-27 Safety device for an exposure lamp in a reproduction apparatus

Country Status (3)

Country Link
US (1) US3571612A (de)
DE (1) DE1813961C3 (de)
GB (1) GB1206699A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3895257A (en) * 1973-02-14 1975-07-15 Rollei Werke Franke Heidecke Photographic enlarger with electronic light control
US5027155A (en) * 1989-01-28 1991-06-25 Brother Kogyo Kabushiki Kaisha Image forming apparatus including mechanisms for exposure lamp exchange

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2178423A (en) * 1939-10-31 inman
US3098448A (en) * 1961-11-15 1963-07-23 Gisser Henry Precision and reliability of timing devices
US3414765A (en) * 1967-02-03 1968-12-03 Dorothy H. Dearman Flashlamp circuit with a high triggering condenser and a load condenser in parallel

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2178423A (en) * 1939-10-31 inman
US3098448A (en) * 1961-11-15 1963-07-23 Gisser Henry Precision and reliability of timing devices
US3414765A (en) * 1967-02-03 1968-12-03 Dorothy H. Dearman Flashlamp circuit with a high triggering condenser and a load condenser in parallel

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3895257A (en) * 1973-02-14 1975-07-15 Rollei Werke Franke Heidecke Photographic enlarger with electronic light control
US5027155A (en) * 1989-01-28 1991-06-25 Brother Kogyo Kabushiki Kaisha Image forming apparatus including mechanisms for exposure lamp exchange

Also Published As

Publication number Publication date
DE1813961C3 (de) 1974-03-28
DE1813961B2 (de) 1973-09-13
DE1813961A1 (de) 1969-08-07
GB1206699A (en) 1970-09-30

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