Laser recording apparatus
AssigneeMinolta Camera Kabushiki Kaisha
InventorAkiyoshi Hamada
Life of this patent
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Abstract
Disclosed is a tone reproducible laser recording apparatus in which a laser beam is produced by a pulse signal modulated in amplitude and also in pulse width in accordance with a multi-tone image signal and/or another factor. This apparatus, when a semiconductor laser is used as a laser light source, further includes an optical element disposed in an optical path of the beam. The optical element cuts off light in a range under a threshold wavelength to enlarge a linearity between exciting current and light outputs.
Claims16
A laser recording apparatus being adapted to modulate a laser beam by a multi-tone image signal and to scan the beam across a recording medium, said apparatus comprising;
- a laser light source,
- first means for producing a first pulse signal modulated in amplitude in accordance with the image signal,
- second means for producing a second pulse signal modulated in pulse width in accordance with the image signal,
- means for composing the first and second pulse signals to produce a pulse signal modulated in amplitude and width,
- means for modulating the laser beam in response to the pulse signal from the composing means, and
- means for scanning the beam across the recording medium.
A laser recording apparatus being adapted to modulate a laser beam by a multi-tone image signal and to scan the beam across a recording medium, said apparatus comprising;
- a laser light source,
- first means for producing a first pulse signal modulated in amplitude in accordance with the image signal,
- second means for producing a second pulse signal modulated in pulse width in accordance with an input signal with selected degree,
- means for composing the first and second pulse signals to produce a pulse signal for modulating the laser beam,
- means for modulating the beam in response to the pulse signal from the composing means, and
- means for scanning the beam across the recording medium.
A laser recording apparatus being adapted to modulate a laser beam by a multi-tone image signal and to scan the beam across a recording medium, said apparatus comprising;
- a semiconductor laser light source for producing the laser beam,
- means for modulating the beam in response to the image signal,
- means for scanning the beam across the recording medium, and
- an optical element disposed in a light path of the scanning means for cutting off light in a range under a threshold wavelength which corresponds to a threshold exciting current.
An improved laser recording apparatus for recording information of various degrees of image tone on a photoconductive member that can be made into a copy image by an electrophotographic process, comprising:
- a laser light source;
- control means for controlling the output of the laser light source to vary intensity and duration of the laser output;
- means for receiving an information signal indicative of the information to be recorded;
- means for producing an amplitude modulated signal in response to the information signal;
- means for producing a pulse width modulated signal in response to the information signal;
- means for applying the amplitude modulated and pulse width modulated signals to the control means to vary the intensity and duration of the laser output, and
- means for scanning the photoconductive member with the controlled laser light source to record the information.
In an electrophotographic apparatus having an improved laser recording apparatus for recording information of various degrees of image tone, the improvement comprising:
- a photoconductive member that can repetitively receive images for copying by an electrophotographic process;
- a laser light source for providing a laser output;
- control means for controlling the output of the laser light source to vary intensity and duration of the laser output;
- means for providing an information signal indicative of the information to be recorded, the information signal comprises a plurality of bits, a first predetermined number of bits providing an amplitude modulation signal and a second predetermined number of bits providing a pulse width modulation signal;
- means for producing an amplitude modulated signal in response to the information signal;
- means for producing a pulse width modulated signal response to the information signal;
- means for applying the amplitude modulated and pulse width modulated signals to the control means to vary the intensity and duration of the laser output;
- means for scanning the photoconductive member with the controlled laser light source to record the information;
- and
- means for reducing any laser light having wavelengths below a laser threshold current level.
Dependencies are inferred from the claim text.