JPS61163355A - Laser printer - Google Patents

Abstract

PURPOSE:To obtain printing outputs of both of an ordinary paper and a photosensitive paper by providing an optical path switching means in the optical path of an optical beam to switch the optical path to a photosensitive drum or the photosensitive paper fed in a uniform speed. CONSTITUTION:An optical switching mirror 6 which is driven to the position indicated by a solid line and the position indicated by a broken line in the figure by a driving means 7 is arranged between an ftheta lens 4 of a laser printer and a photosensitive drum 5. When printing for galley proof is performed for the ordinary paper, the mirror 6 is switched to the position indicated by the solid line, and the printing output of the ordinary paper is obtained through the drum 5. When printing of good quality is obtained on the photosensitive paper, the mirror 6 is switched to the position indicated by the broken line, and the optical beam is projected to the photosensitive paper 9 to attain printing. Thus, printing outputs to the ordinary paper and the photosensitive paper are obtained with simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a laser printer that records characters, figures, etc. using laser light.

(Prior Art) There are two types of recording paper conventionally used in laser printers: photosensitive paper and plain paper. Photosensitive paper that produces print output has very good image quality and is ideal for final output such as printing plates, but it has the problem of high printing costs and the fact that it cannot be seen visually unless it is developed. There is a point. Those that print on plain paper have low running costs, but the image quality is at the same level as galley printing, which is not very good.

(Problem to be Solved by the Invention) For printing one typesetting, both the galley printing υ and the final output are required, but conventionally, both print outputs were performed by separately configured laser printers. This has the disadvantage that the equipment costs are high.

The present invention was made in view of these shortcomings in the conventional technology, and its purpose is to use a single device for galley printing (printing on plain paper) and for final output (printing on photosensitive paper). The aim is to realize a laser printer that can provide both print outputs.

(Means for Solving the Problems) The present invention, which solves the above-mentioned drawbacks, includes an optical scanning means for scanning a light beam from a light source, and a constant speed system for transferring an electrostatic latent image onto plain paper to obtain a printed output. a photosensitive drum that rotates at a constant speed; a photosensitive paper feeding device that feeds the photosensitive paper at a constant speed; and a light beam scanned by the optical scanning device that directs the light beam to either the photosensitive drum side or the photosensitive paper side that is fed at a constant speed. and an optical path switching means for projecting the light to the side.

(Example) Fig. 1 is a perspective view of the configuration of an apparatus according to the present invention, and Fig. 2 is a side view thereof, together with the main constituent blocks. In these figures, l is a light source such as a laser, 2 is a converging lens that converges the light from the light source 1 to a predetermined beam diameter, and 3 is a polygon mirror rotated at a constant speed by a motor 30, which constitutes an optical scanning means. ing. 4 is an fθ lens, 5 is a photosensitive drum,
5o is a drive motor for the photosensitive drum 5. fθ lens 4
is for correcting the reflected light reflected by the polygon mirror 3 so that the diameter of the light spot on the projection surface of the photosensitive drum 5 or photosensitive paper 90 to be described later is constant and the light spot is scanned at a constant speed.

Reference numeral 6 denotes an optical path switching mirror, which is installed between the fθ lens 4 and the photosensitive drum 5, and is driven by the driving means 7 to the positions shown by solid lines and broken lines, so that the light beam emitted from the fθ lens 4 is Switch the optical path.

Reference numeral 8 denotes a feeding means for the photosensitive paper 9, such as a feeding roll. IO is a control circuit that controls the entire device, and is composed of, for example, a microprocessor.

The operation of the device configured in this manner will be described next. First, for example, when it is desired to obtain a print output for galley opening on plain paper, the optical path switching mirror 6 is driven by the driving means 7 to the position shown by the solid line. In this state, the light beam exiting the fθ lens 4 is directed to the optical path switching mirror 6.
The light beam passes over the photosensitive drum 5, is projected onto the photosensitive surface of the photosensitive drum 5, and is horizontally scanned over this in the direction of the arrow a. The photosensitive drum 5 is rotated at a constant speed (sub-scanning) by a drive motor 50, and the photosensitive surface is exposed by a scanning light spot to form an electrostatic latent image.

Although not shown, a lightless means, a developing means, etc. are installed on the surface of the photosensitive drum 50, and the electrostatic latent image formed on the photosensitive drum 5 by a known method is transferred onto plain paper. Obtain printout on plain paper.

Next, when you want to print out on photosensitive paper such as photographic paper or film, the optical path switching mirror 61f! :, driving means 7
The position shown by the broken line is f0 lens 4.
for example, to a position where the light beam from the mirror is reflected in a perpendicular direction. In this state, the light beam emitted from the fθ lens 4 is reflected by the optical path switching mirror 6 as shown by the broken line, and the reflected light is projected onto the photosensitive paper 9 in the direction in which the photosensitive paper 9 is fed (in the direction indicated by the arrow). ] and the direction perpendicular to (arrow 1
direction). The photosensitive paper 9 is thereby exposed to light.

Here, if the sensitivity of the photosensitive drum 5 and the photosensitive paper 9 are significantly different, the power and energy of the emitted light of the light source 1 may be switched in synchronization with the drive of the optical path switching mirror 6, if necessary. good.

In the above embodiment, a polygon mirror is used as the optical scanning means, but a galvanometer mirror or an acousto-optic effect element (AOE) Q may be used. Further, although a Kfθ lens is used to eliminate scanning distortion, other means may be used.

(Effects of the Invention) As explained above, according to the present invention, the light source, optical scanning means, fθ lens, etc. can be used in common for obtaining print output on plain paper and for obtaining print output on photosensitive paper. With this, it is possible to realize a laser printer that can obtain both print outputs with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the structure of an apparatus according to the present invention, and FIG. 2 is a side view and a block diagram of the structure. 1... Light source 2... Converging lens 3...
Polygon mirror 4... fθ lens 5... Photosensitive drum 6... Optical path switching Mi 2-7... Middle drive stage
8... Photosensitive paper feeding means 9... Photosensitive paper
10...Control circuit 1. .

Claims (1)

[Claims] an optical scanning device that scans a light beam from a light source; a photosensitive drum that rotates at a constant speed to transfer an electrostatic latent image onto plain paper to obtain print output; and a photosensitive paper feeding device that feeds the photosensitive paper at a constant speed; A laser printer comprising an optical path switching means for projecting a light beam scanned by the optical scanning means onto either the photosensitive drum side or the photosensitive paper side that is fed at a constant speed.