JPS5722265A - Exposure control device for copying machine - Google Patents

Exposure control device for copying machine

Info

Publication number
JPS5722265A
JPS5722265A JP9720180A JP9720180A JPS5722265A JP S5722265 A JPS5722265 A JP S5722265A JP 9720180 A JP9720180 A JP 9720180A JP 9720180 A JP9720180 A JP 9720180A JP S5722265 A JPS5722265 A JP S5722265A
Authority
JP
Japan
Prior art keywords
circuit
output voltage
voltage
limiting
output
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.)
Granted
Application number
JP9720180A
Other languages
Japanese (ja)
Other versions
JPS639207B2 (en
Inventor
Takeshi Nozaki
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.)
Toshiba Corp
Original Assignee
Toshiba Corp
Tokyo Shibaura Electric 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 Toshiba Corp, Tokyo Shibaura Electric Co Ltd filed Critical Toshiba Corp
Priority to JP9720180A priority Critical patent/JPS5722265A/en
Publication of JPS5722265A publication Critical patent/JPS5722265A/en
Publication of JPS639207B2 publication Critical patent/JPS639207B2/ja
Granted legal-status Critical Current

Links

Classifications

    • 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

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Exposure Or Original Feeding In Electrophotography (AREA)
  • Control Of Exposure In Printing And Copying (AREA)
  • Control Or Security For Electrophotography (AREA)

Abstract

PURPOSE:To automaticably obtain optimum exposure by limiting the output voltage of a photodetecting circuit by a limiting circuit in accordance with the output thereof, adding this limited voltage to the output voltage of a voltage forming circuit and applying the same to a comparator. CONSTITUTION:In the case of a dark original, the reflected light from the original is less and the quantity of light incident to a photodetecting circuit 40 is also less, hence the output voltage of a limiting circuit 38 is the value consisting of limiting the output voltage of the circuit 40 to a certain degree but is still low. Hence, if the value adding the output voltage of the circuit 38 to the output voltage of a waveform shaping circuit 34 is lower than the reference voltage from a reference voltage generating circuit 39, an error amplifier 37 amplifies the difference thereof and outputs the same to a trigger pulse generating circuit 41. Then, the circuit 41 controls a thyristor 32 so as to increase its conduction angle, thereby increasing the quantity of light of an exposure lamp 2.
JP9720180A 1980-07-16 1980-07-16 Exposure control device for copying machine Granted JPS5722265A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP9720180A JPS5722265A (en) 1980-07-16 1980-07-16 Exposure control device for copying machine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP9720180A JPS5722265A (en) 1980-07-16 1980-07-16 Exposure control device for copying machine

Publications (2)

Publication Number Publication Date
JPS5722265A true JPS5722265A (en) 1982-02-05
JPS639207B2 JPS639207B2 (en) 1988-02-26

Family

ID=14185986

Family Applications (1)

Application Number Title Priority Date Filing Date
JP9720180A Granted JPS5722265A (en) 1980-07-16 1980-07-16 Exposure control device for copying machine

Country Status (1)

Country Link
JP (1) JPS5722265A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6031132A (en) * 1983-07-30 1985-02-16 Mita Ind Co Ltd Automatic exposing device
JPS6035752A (en) * 1983-08-06 1985-02-23 Canon Inc Image control device
JPS60216347A (en) * 1984-03-23 1985-10-29 Minolta Camera Co Ltd Automatic exposing device of electrophotographic copying machine
JPS61189579A (en) * 1985-02-19 1986-08-23 Sharp Corp Exposure adjusting device for copying machine
JPS61190328A (en) * 1985-02-20 1986-08-25 Fuji Xerox Co Ltd Exposing device

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5182630A (en) * 1975-01-16 1976-07-20 Minolta Camera Kk

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5182630A (en) * 1975-01-16 1976-07-20 Minolta Camera Kk

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6031132A (en) * 1983-07-30 1985-02-16 Mita Ind Co Ltd Automatic exposing device
JPH0554094B2 (en) * 1983-07-30 1993-08-11 Mita Industrial Co Ltd
JPS6035752A (en) * 1983-08-06 1985-02-23 Canon Inc Image control device
JPS60216347A (en) * 1984-03-23 1985-10-29 Minolta Camera Co Ltd Automatic exposing device of electrophotographic copying machine
JPH071377B2 (en) * 1984-03-23 1995-01-11 ミノルタ株式会社 Automatic exposure device for electrophotographic copying machine
JPS61189579A (en) * 1985-02-19 1986-08-23 Sharp Corp Exposure adjusting device for copying machine
JPS61190328A (en) * 1985-02-20 1986-08-25 Fuji Xerox Co Ltd Exposing device

Also Published As

Publication number Publication date
JPS639207B2 (en) 1988-02-26

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