JPS5722266A - Exposure control device for copying machine - Google Patents

Exposure control device for copying machine

Info

Publication number
JPS5722266A
JPS5722266A JP9720280A JP9720280A JPS5722266A JP S5722266 A JPS5722266 A JP S5722266A JP 9720280 A JP9720280 A JP 9720280A JP 9720280 A JP9720280 A JP 9720280A JP S5722266 A JPS5722266 A JP S5722266A
Authority
JP
Japan
Prior art keywords
circuit
voltage
output voltage
reference voltage
trigger pulse
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
JP9720280A
Other languages
Japanese (ja)
Other versions
JPS639208B2 (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 JP9720280A priority Critical patent/JPS5722266A/en
Publication of JPS5722266A publication Critical patent/JPS5722266A/en
Publication of JPS639208B2 publication Critical patent/JPS639208B2/ja
Granted legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B27/00—Photographic printing apparatus
    • G03B27/72—Controlling or varying light intensity, spectral composition, or exposure time in photographic printing apparatus

Landscapes

  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (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 automatically obtain always optimum exposure by adding the output voltage of a photodetecting circuit to the output voltage of a voltage forming circuit, applying the same to a comparator, comparing the same with preset reference voltage and controlling the quantity of light of an exposure lamp. CONSTITUTION:If there is an error between the output voltage of a waveform shaping circuit 34 and the reference voltage from a reference voltage generating circuit 39, the output voltage of an error amplifier 37 increases or decreases in accordance with the size of said error, in accordance with which, the generating phase of the trigger pulse outputted from a trigger pulse generating circuit 41 changes as well. Hence, the conduction angle of a thyristor 32 changes and this change is fed back to the amplifier 37 by the trigger pulse to a spurious load circuit 33. Therefore, the device operates as a whole in such a way that the output voltage of the circuit 34 is made equal to the reference voltage from the circuit 39, that is, the voltage applied across an exposure lamp 2 is made constant at all times against the voltage fluctuations of a power source 31.
JP9720280A 1980-07-16 1980-07-16 Exposure control device for copying machine Granted JPS5722266A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP9720280A JPS5722266A (en) 1980-07-16 1980-07-16 Exposure control device for copying machine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP9720280A JPS5722266A (en) 1980-07-16 1980-07-16 Exposure control device for copying machine

Publications (2)

Publication Number Publication Date
JPS5722266A true JPS5722266A (en) 1982-02-05
JPS639208B2 JPS639208B2 (en) 1988-02-26

Family

ID=14186016

Family Applications (1)

Application Number Title Priority Date Filing Date
JP9720280A Granted JPS5722266A (en) 1980-07-16 1980-07-16 Exposure control device for copying machine

Country Status (1)

Country Link
JP (1) JPS5722266A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0722843A (en) * 1993-06-30 1995-01-24 Nec Corp Modulation degree control circuit

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 (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0722843A (en) * 1993-06-30 1995-01-24 Nec Corp Modulation degree control circuit

Also Published As

Publication number Publication date
JPS639208B2 (en) 1988-02-26

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