JPH04221975A - Optical head for electrophotographic system printer - Google Patents

Abstract

PURPOSE:To obtain the laser beam of stable light quantity by always monitoring the light quantity of reflected light obtained by reflecting the light from a laser light source by a polygon mirror and cooling the laser light source when the light quantity becomes equal to or under a reference value so that the light quantity thereof may be restored. CONSTITUTION:While the polygon mirror 2 rotates, it reflects the light from the laser light source 1 so as to perform scanning. An analog photosensor 3 inputs the reflected light from the mirror 2 and outputs analog photosensor output 5 in proportion to the light quantity of the reflected light. A light quantity decision device 4 is connected to the photosensor 3 and inputs the output 5, then outputs a synchronizing pulse 6 by the output 5 and drives a fan 7 so as to cool the light source 1 in the case of deciding that the light quantity is equal to or under the reference value. By such constitution, when the light quantity from the light source 1 is lowered, the light source 1 is cooled to restore the light quantity.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head for an electrophotographic printer, and more particularly to an optical head for an electrophotographic printer using a laser light source.

0002

2. Description of the Related Art A conventional optical head of an electrophotographic printer using a laser light source has a polygon mirror that reflects and scans light from the laser light source, and synchronization timing is detected by the light reflected from the polygon mirror. It is configured only as follows.

0003

[Problems to be Solved by the Invention] As mentioned above, the conventional optical head of an electrophotographic printer using a laser light source is configured to detect synchronization timing only by the reflected light of a polygon mirror. In order to prevent the light intensity from decreasing due to the temperature of the light source increasing,
It is necessary to use a special sensor, which has the disadvantage of increasing the price of the printer.

0004

[Means for Solving the Problems] An optical head of an electrophotographic printer of the present invention includes a laser light source, a polygon mirror that reflects and scans light from the laser light source by rotational movement, and a polygon mirror that reflects light from the polygon mirror. The device includes an analog optical sensor that inputs light, a light amount determiner connected to the analog optical sensor to determine the amount of light, and a cooling means that cools the laser light source based on a signal from the light amount determiner.

[0005]

Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

As shown in FIG. 1, the polygon mirror 2 is
The light from the laser light source 1 is reflected and scanned while rotating. The analog optical sensor 3 receives the reflected light from the polygon mirror 2 and outputs an analog optical sensor output 5 proportional to the amount of light. The light quantity determiner 4 is connected to the analog optical sensor 3 and inputs the analog optical sensor output 5,
A synchronizing pulse 6 is output by the analog optical sensor output 5, and when it is determined that the amount of light is less than a reference value, a fan 7 is driven to cool the optical laser light source 1.

With this configuration, when the amount of light from the optical laser light source 1 decreases, it is possible to cool the optical laser light source 1 and restore the amount of light.

[0009]

[Effects of the Invention] As explained above, the optical head of the electrophotographic printer of the present invention constantly monitors the amount of light reflected by the polygon mirror from the laser light source, and when the amount of light falls below a reference value, , because the optical laser light source can be cooled and its light intensity can be recovered, it has the effect of always obtaining a stable amount of laser light, and it does not require any special sensors, which reduces the cost of printer equipment. This has the effect of being able to obtain a stable amount of laser light without increasing the amount of light.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention.

[Explanation of symbols]

1 Laser light source 2 Polygon mirror 3 Analog optical sensor 4. Light amount judger 5 Analog light sensor output 6 Sync pulse 7 Fan

Claims (1)

[Claims] 1. A laser light source, a polygon mirror that reflects and scans light from the laser light source through rotational movement, an analog photosensor that inputs reflected light from the polygon mirror, and is connected to the analog photosensor. 1. An optical head for an electrophotographic printer, comprising: a light amount determiner for determining the amount of light emitted by the laser; and a cooling means for cooling the laser light source based on a signal from the light amount determiner.