Abstract: This invention relates to a laser irradiation device of laser printers in which has a simplified laser diode excitation control device, comprising a laser beam emitter, a first lens for converting the laser beam emitted from the laser beam emitter into parallel laser beam, a polygonal mirror for reflecting the parallel laser beam, the polygonal mirror being rotated and having a plurality of reflection surfaces and sensing part, the sensing part sensing the starting points of each reflection surfaces, a second lens for receiving the laser beam reflected by the polygonal mL-Tor, and a controller for synthesizing an output signal from the sensing part of the polygonal mirror with a picture signal and generating control signal to control the laser beam emitter.

Abstract: A scanning device for an electronic photography printer which comprises a photosensitive drum, a rotary cylinder horizontally disposed and provided with spiral slits which are spaced from one another, an LED array horizontally penetrating the inside of the rotary cylinder and having a plurality of LEDs which are disposed on the LED array and each having a width of the same distance as the space between respective spiral slits of the rotary cylinder, a horizontal slit plate disposed between the photosensitive drum and the rotary cylinder and having a plurality of slits which are inclined on the basis of the horizontal line of the horizontal slit plate and spaced from one another, and a self-focus lens array horizontally disposed between the photosensitive drum and the horizontal slit plate.

Abstract: A device for sensing feeding of copying papers, which may promptly detect paper jamming and misfeeding occurring at a paper feed route of a copying apparatus, such as a laser printer or a copier, thereby preventing pollution by toner or damage of the apparatus. To this end, the device comprises a ratatable actuator of a circular disk shape having a plurality of slits, a first sensor disposed outwardly of the actuator to sense a paper feed condition, and a second sensor disposed outwardly of the actuator to sense the presence and absence of the paper, whereby both the actual feed state and feed distance of the paper may be promptly detected during feeding of the papers.

Abstract: In the copying machine including an electrifier, a developer, a developer roller, a transcriber, a discharging brush, a cleaning blade, a cleaning portion and a front and a rear guides, the guide and the discharging brush are grounds, the predetermined symmetric AC voltage is directly applied to the drum to generate the asymmetric AC power in the surface of a photosensitive drum.