JPS5846304A - Laser light arranging device - Google Patents

Abstract

PURPOSE:To condense laser lights closely with a simple optical system and to use them effectively for a high-speed printer or the like, by reflecting totally plural parallel laser lights on reflective films of slope parts of a transparent optical material so that they are close to one another. CONSTITUTION:In an arranging optical member 10 using an optical glass, apexes of an incidence part 13 and an emission part 15 whose sections are approximately triangular are connected to each other by a flat intermediate part 14, and all of the surface except end faces 11 and 12 is coated with a metallic reflective film 16. When three parallel laser lights 1a-1c are made incident to the end face 11, the light 1b goes straightly to become a light 1b'. Lights 1a and 1c are reflrected totally in the intermediate part 14 repeatedly after being reflected totally on the reflective film 16 of slope parts 13a and 13b and are reflected totally on the reflective film 16 of slope parts 15a and 15b and are emitted as lights 1a' and 1c' from the end face 12 without overlapping the light 1b'. Thus, three lights are condensed closely to one another and are used effectively for a high-speed printer or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aligns a plurality of laser beams to form a single laser beam alignment device that can be used in laser printers and the like.

Conventional printers that use laser light are sometimes combined with electrophotography, for example, by irradiating laser light onto a high-speed rotating polygon prism.
The reflected light is scanned in the generatrix direction of the electrophotographic photosensitive drum (this is called the main scanning direction), and the photosensitive drum is further rotated (this rotating direction is called the Jil scanning direction). A method of scanning and sequentially writing on the photosensitive drum surface is adopted. In this case, considering the relationship between the deflection of the laser beam in the main scanning direction and the rotational speed of the photosensitive drum in the sub-scanning direction, the laser beam may overlap on the photosensitive drum surface or gaps may occur due to no irradiation. In order to prevent this, the rotation period of the photosensitive drum is usually detected so that the laser beam is uniformly irradiated onto the surface of the photosensitive drum. In this case, it is particularly necessary to consider the relationship between the irradiation energy of the laser beam and the sensitivity of the photosensitive drum. In other words, the energy per unit time of the laser beam must be sufficient to correspond to the exposure of the photosensitive drum, and if the energy of the laser beam is insufficient for the sensitivity of the photosensitive drum, the brightness of the laser beam must be reduced. Increase the speed of the photosensitive drum or reduce the speed in the main scanning direction.
A method is used to lengthen the duration of the laser beam emitted. However, increasing the brightness of the laser light has a negative effect on the durability of the laser light-emitting device, so there is a limit. Furthermore, if the speed in the main scanning direction is reduced and the irradiation time is lengthened, the speed in the sub-scanning direction will also be reduced accordingly, resulting in a reduction in the recording speed.

However, recently, there has been a particular demand for a printer device, the Kalli stenography sickle, which uses this laser light. However, in this conventional device, even if the sensitivity of the photosensitive drum sufficiently corresponds to the energy of the laser beam, there is a limit to the rotation speed of the rotating polygon prism, etc., for example, when the rotation speed exceeds 300 GO rpm. Rotation becomes unstable. This causes speed fluctuations in the main scanning direction, and the speed tK in the sub-scanning direction also influences, giving rise to a limit to the rate of rotation.

Therefore, in order to further improve the recording speed, a plurality of beams are separated by a plurality of first beams, and the plurality of beams are simultaneously irradiated onto the surface of the photosensitive drum in the main scanning direction. In this case, it is necessary to prevent the multiple beams from overlapping on the surface of the photosensitive drum, but at the same time, it is necessary to ensure that the multiple beams are completely separated and that there are no gaps between the beams that are not irradiated. The speed in the scanning direction and the rotational speed of the photosensitive drum must be synchronized. However, in this control, it is necessary to strictly adjust the relationship among the deflection of the laser beam, the interval between the laser beams, and the rotational speed of the photosensitive drum, which complicates the signal system between the plurality of laser beams. Because the KIm image on the photosensitive drum surface is aligned, k
In addition to simply separating multiple laser light signals in time series, it is necessary to insert laser light delayed in time series between the laser lights. In practice, it is very difficult to provide signals with complicated delays to the laser beams that are separated in this way in order to finally form an image.

Additionally, semiconductor laser beams are often used to completely separate multiple beams. If the non-light-emitting part between the light-emitting part and the light-emitting part in this laser array is made as small as possible, it is thought that multiple beams will become a continuous beam pair, but in reality, if the non-light-emitting part becomes within the limit, adjacent light-emitting parts The current noise of the array affects its luminance, and the entire array becomes unstable. In order to avoid this, k should be divided into time-series parts to emit light, or in the case of simultaneous light emission, the non-emission part should have a finite width of, for example, 100 IR or more, and the laser beam should be set as shown in Figure 1. It is necessary to separate the lights 1m, 1b, and IC and irradiate them onto the surface of the photosensitive drum 2.

One object of the present invention is to solve the above-mentioned drawbacks and problems, and to avoid overlapping multiple separated laser beams.
It is an object of the present invention to provide a laser beam alignment device that can focus laser beams closely together. It is characterized in that it is reflected and emitted so as to be spatially overlapped by a reflective element provided.

The present invention will be explained in detail based on the embodiments shown in FIGS. 2 and 3.

Figure 2 is a cross-sectional view of a 1° alignment optical member using optical glass, showing six laser beams separated at equal intervals of 1 m and 1°.
b, lc are incident on one end surface 11Fc, and from the other end surface 12 closely spaced laser beams 11I', 1 b', 1c''
It is designed to be ejected as Alignment optical member 1
0 is constructed by integrating an entrance part 13, an intermediate part 14, and an exit part 15, and the entrance part 13 and the exit part 15 have a gradual triangular shape, and their apexes are connected to each other by a flat intermediate part 14. has been done. This alignment optical member 1o is coated with a metal reflective layer ![16] except for its end surface 11.12.
3b and shot JfSill 5) Diagonal iti part 15 m,
The inner surface of 15 b and both sides of the intermediate portion 514 are reflective surfaces for the laser beam, and the thickness of the intermediate portion 13 is
b.

It is scattered with a width of 1c. Since this alignment optical member 1° is intended to emit separated incident laser beams 1 as 1 bslC in a close state without overlapping, the following conditions must be met. That is, if the angle of incidence of the laser beams 1a and 1c on the slopes 13 and 13b of the incident part 13 is Φ, and the thickness of the intermediate part 13 is d, then the length l of the intermediate part 13 is (d/2).
daΦ・(2) Let it be an integer multiple of φ. Further, the inclination angle of the slope portion 15a115b of the injection portion 15 is the slope portion 1! ! , 13
It is the same as b, but in the opposite direction.

Therefore, as shown in the second factor, three laser beams 1 m,
1 b s 1 c arranged at predetermined intervals and aligned optical member 1
When the laser beam 1b enters from the end surface 11 of the incident section 13 of 0, the laser beam 1b that enters the center passes through the incident section 13, the intermediate section 14, and the exit section 15 without any reflection etc. and becomes the laser beam 1.
It is ejected from the end face 12 as b'. On the other hand, the incidence section 13
The laser beam 1a incident above is reflected by the reflection element 16 of the slope portion 13m, guided to the intermediate portion 14, and proceeds while repeating reflection at the intermediate portion 14, reaches the emission portion 15, and is reflected at the slope portion 15aK. , is emitted to the outside as a laser beam 1a' at the same angle as the incident angle. At the time of emission, this laser beam 11' is emitted from the adjacent laser beam 1.
It will be injected in close contact with b' without overlapping it. The laser beam 1C enters the lower part of the incident part 13, is reflected by the slope part ISb, passes through the intermediate part 14, is reflected by the slope part 15b of the emission part 15, and becomes a laser beam 10' which comes into close contact with the laser beam 1b'. is ejected. Therefore,
Laser light 11.1b when incident on alignment optical member 10.

Even if 1C has equally spaced gaps, there is no gap between them at the time of injection, and they are injected in close contact with each other.

FIG. 6 shows an optical configuration diagram of a laser printer device using this alignment optical member 10, and shows three laser beams 1a emitted from a laser emitting device 20 using a semiconductor laser array.

The beams lb and lc pass through a collimator lens 21 for collimating light and enter a polygon prism 22 that rotates at high speed. The scanning light reflected by this polygon prism 22 is transmitted through a correction lens f/θ to prevent the laser beams 1b, 1c from spreading in the main scanning direction.
The light passes through the lens 26 and enters the alignment optical member 10. In this alignment member 10, as described above, the laser beams 11.1b are separated.

1c will be ejected closely and projected onto the surface of the photosensitive drum 2.

By doing so, there is no gap between the plurality of laser beams 11.1b and 1c that are irradiated onto the photosensitive drum 2, and a high-speed rotation can be realized. In the above-described embodiment, an example was explained in which the number of laser beams was six, but it goes without saying that the present invention is not limited to that number. Further, the alignment device according to the present invention is not limited to optical glass covered with a reflective film, and may be used, for example, with a cavity source glass material or metal material whose inner surface is coated with a reflective film.

As explained above, the laser beam alignment device according to the present invention can bring a plurality of spatially separated laser beams into close contact with each other using a simple optical system without performing complicated electrical processing. For example, it can be effectively used in high-speed printer devices.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram for explaining the irradiation of laser light onto a photosensitive drum in a conventional printer device, Figures 2 and 3
The figures show one embodiment of the laser beam alignment device according to the present invention, FIG. 2 is a sectional view thereof, and FIG. 6 is a configuration diagram when applied to a printer device. Symbols 1, 1b, 1c, 1m', 1b', 10' are laser beams, 2 is a photosensitive drum, 10 is an alignment optical member, is an incident part, IAm, 16b is a slope part, 14 is an intermediate part, 15
15m and 15b are inclined surfaces, and 16 is a reflective film. 0

Claims (1)

[Claims] L! ! A laser beam consisting of a plurality of parallel light beams that are separated in time is reflected by a reflective film provided on an inclined surface of a transparent optical body so as to be closely spaced without spatially overlapping, and then emitted. Laser light alignment device. 2. Connect the tops of the entrance part and the exit part, each having a substantially triangular cross section, with a flat intermediate part having a thickness equivalent to the width of the tip of the ray,
A laser beam alignment device according to claim 1E, wherein the light is reflected by a slope portion provided with a reflective material and an intermediate portion similarly provided with a reflective material between the incident portion and the exit portion.