Recorders – Performance of multiple functions of steam and gas engines – Pressure responsive element
Patent
1985-08-26
1987-12-01
Goldberg, E. A.
Recorders
Performance of multiple functions of steam and gas engines
Pressure responsive element
346 76L, 346108, 346160, 369 44, 358300, 372 29, 250205, G01D 1800, G11B 700, H04N 123, H01S 313
Patent
active
047107790
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
The present invention relates to a recording apparatus for using a semiconductor laser as a light source so that the scanning operation may be conducted with the laser beam which has been modulated on the basis of picture information.
2. Background Art
Since the optical output of a semiconductor laser has a high temperature dependency, it has to be stabilized so that the semiconductor laser may be used as the light source for a recording apparatus. As one of those stabilizing methods, according to the prior art, there has been known a method for conducting the temperature control of a laser diode. However, since there exists a temperature difference (which is not constant) between a case (i.e., a mount) providing a temperature detection point and the chip of the laser diode, the optical output is so highly fluctuated as to make it difficult for that method by itself to limit the optical output within an allowable fluctuation range. In the recording apparatus of that kind, moreover, since the average output of the laser diode during the recording operation is not constant, it has also been impossible to use such a stabilizing method in a laser for light communication which controls the drive current of the laser diode with the average output of the laser diode.
Under the circumstances thus far described, there has recently been proposed a recording apparatus using a method, in which a sampling period synchronized with a beam position detection signal is prepared during a recording period so that the laser beam may be partially sampled through a beam splitter to detect the intensity of the laser beam thereby to control the drive current of the laser diode. In this recording apparatus, however, since the sampling period is prepared during the recording period and upon each scanning operation of one line, there arises a problem that the sampling period is so short that the frequency response of a feedback system has to be remarkably enhanced. This results in a limit in increasing the printing speed. Moreover, there arises another problem that the sampling operation has to be conducted in synchronism with the beam detection signal to require complex sequences so that the circuit construction becomes complicated. Still another problem is that the non-linearity of the beam splitter leads to a detection error in the beam intensity to rise a disadvantage.
DISCLOSURE OF INVENTION
The present invention has been conceived so as to solve the problems thus far described and has an object to provide a recording apparatus which is enabled to print at a high speed while having a simple construction.
The fundamental construction of the present invention for achieving that object is characterized in that a semiconductor laser is driven before the beginning of a recording period to determine its drive current for making the monitor current of its optical output constant so that the drive current may be used as that of the semiconductor laser during the recording period.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic view showing the construction of the essential portion of one embodiment of a recording apparatus according to the present invention;
FIG. 2 is a perspective view showing a semiconductor laser device appearing in FIG. 1;
FIG. 3 is an electric circuit diagram showing the essential portion of the apparatus of FIG. 1;
FIG. 4 is an explanatory view showing the writing operation of a badge or the like on a photosensitive drum; and
FIG. 5 is an operation explaining view (i.e., a time chart) of the apparatus of FIG. 1.
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described in detail in the following with reference to the accompanying drawings.
FIG. 1 is a schematic view showing the construction of the essential portion of one embodiment of the recording apparatus according to the present invention using a transfer type electronic photography. Reference numeral 1 indicates a semiconductor laser device which has a laser diode therein, and numeral 2 ind
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patent: 4363116 (1982-12-01), Kleuters et al.
patent: 4443695 (1984-04-01), Kitamura
patent: 4443696 (1984-04-01), Taboada
Akanabe Yuichi
Funaki Shinsuke
Ikeda Hiroaki
Bierman Jordan B.
Goldberg E. A.
Konishiroku Photo Industry Co,., Ltd.
Preston Gerald E.
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