Exposure lamp control for image forming apparatus
AssigneeKabushiki Kaisha Toshiba
InventorsTakeshi Sanbayashi, Hideshi Oushiden
Life of this patent
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Abstract
In a copy machine with a variable copy magnification, light reflected from a document, which is exposed by an exposure lamp, is led to a photosensitive drum to form thereon a copy image of a predetermined size and also led to a photo detecting circuit to detect a density of the document and to control an amount of exposure. An exposure control circuit of the copy machine comprises a magnification setter for generating a magnification signal dependent on a magnification as selected, a control signal generating circuit for generating a control signal according to the magnification signal and the output signal from the photo detecting circuit and a power source circuit for applying a power voltage to the exposure lamp according to the control signal.
Claims8
An image forming apparatus comprising:
- lamp means for exposing a document;
- magnification setting means for generating a magnification signal;
- means, connected to said magnification setting means, for forming an image of the document on a recording medium based on a light from the exposed document, a size of the image being determined by the magnification signal;
- memory means, connected to said magnification setting means, which stores digital data corresponding to various magnifications and produces the digital data in response to the magnification signal;
- and
- lamp control means, connected to said lamp means and memory means, for applying a power voltage to said lamp means in accordance with the digital data generated from said memory means.
An image forming apparatus comprising:
- lamp means for exposing a document;
- magnification setting means for generating a magnification signal;
- detecting means for detecting a density of the document based on a light from the exposed document and for producing a density voltage corresponding to the detected density;
- means, connected to said magnification setting means, for forming an image of the document on a recording medium based on a light from the exposed document, a size of the image being determined by the magnification signal;
- memory means, connected to said magnification setting means, which stores digital data corresponding to various magnifications and produces the digital data in response to the magnification signal;
- and
- lamp control means, connected to said detecting means, lamp means and memory means, for applying a power voltage to said lamp means in accordance with the density voltage and the digital data generated from said memory means.
Dependencies are inferred from the claim text.