JPS6318321A - Hologram scanner - Google Patents

Abstract

PURPOSE:To increase an effective scanning period rate by making two reflected light beams incident on one sector of one hologram disk at the same angle closely to each other by using a reflecting member which has two reflecting surfaces at a 90 deg. relative angle. CONSTITUTION:The relative angle between the two reflecting surfaces M1 and M2 of the reflecting member 3 is set to 90 deg. and when two beams are projected on the reflecting surfaces M1 and M2 in the opposite directions, the two beams are reflected in the same direction in parallel. A reflecting member 5 also has its reflecting surfaces M1 and M2 formed in exactly the same way and two parallel incident beams are reflected by the reflecting surfaces M1 and M2 to travel in the mutually opposite directions of 180 deg.. Thus, the two beams are made incident on one sector at the same angle of incidence closely to each other. Thus, the effective scanning period rate can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hologram scanner that scans a plurality of beams.

In general, in laser color printers that use multiple photoreceptor drums, multiple laser beams modulated according to each color image information are scanned and irradiated onto the surface of each corresponding photoreceptor drum. A color image is recorded by exposing the recording paper to light and developing the images with toner of each color, thereby superimposing and transferring the resulting images onto one recording paper.

■ The present invention resides in such a laser color printer,
To provide a hologram scanner with a simple structure that can optimally scan a plurality of beams using one hologram disk.

In order to achieve the object, the present invention provides a hologram scanner that irradiates a single hologram disk with a plurality of beams and uses each diffracted beam as a scanning beam. Using a member, the first beam is irradiated on one reflective surface and the second beam is irradiated on the other reflective surface, and each of the reflected lights approaches each other at the same angle within one sector of one hologram disk. This makes it possible to improve the effective scanning period rate.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the hologram scanner according to the present invention, FIG.
As shown in a) and (b), the laser beams emitted from two semiconductor lasers 1, which are provided opposite to each other, pass through the beam forming optical system 2 and are reflected by the reflecting member 3. The light is reflected from each reflecting surface and is incident on the hologram disk 4 at the same angle. The hologram grating direction on the hologram disk 4 is the radial direction, and the beams each reflected by one reflecting member 3 divided into a plurality of sectors (6 sectors are shown here) are as follows:
Each beam is incident on the hologram disk 4 at a specific angle determined by the wavelength of the beam and the pitch of the hologram grating.

Also, the beams diffracted by the hologram disk 4 are reflected on each reflecting surface of the reflecting member 5, and are irradiated onto the two photoconductor tram 9 through the fO lens 6, the reflecting mirror 7, and the cylindrical lens 8, respectively. It has become. At this time, the hologram disk 4 rotates at a constant speed in the direction indicated by the arrow a in the figure, so that the beams are sent at a constant speed in the direction already indicated by the arrow in the figure, with respect to the surface of each photoconductor drum 9 that is sent in the sub-scanning direction. Main scanning is performed. In the figure, numeral 10 indicates a drive motor for the hologram disk 4.

In the reflecting member 3, as shown in Fig. 2, the relative angle between the two reflecting surfaces 31 and 32 is set to 90'', and when two beams are irradiated from opposite directions to the reflecting surfaces Ml and M2, respectively, , the two beams are reflected in parallel in the same direction.In this case, each reflecting surface M 1 , M 2
The two beams that are respectively incident on the two beams do not need to be in the same plane or on the same straight line, but only need to be parallel and the directions in which the beams travel make 180 degrees to each other.

The reflecting member 5 is formed exactly the same as the reflecting member 3, and the two parallel beams are reflected on the reflecting surfaces Ml and M.
2 and travel in opposite directions that are 180° different from each other.

In the hologram scanner according to the present invention configured as described above, the two beams can be made to approach each other at the same angle of incidence using the reflecting member 3 and be incident on one sector of the hologram disk 4, so that effective scanning can be achieved. It will be possible to improve the period rate. That is, as shown in FIG. 3, if the respective incident positions P□ p2 of the two beams on the hologram sector 41 are offset by an angle α from the rotation center ○ of the hologram disk 4, the angle α due to the rotation of the hologram disk 4 Scanning angles θ□, θ2 . from the optical axis center C of each beam. ψ0. The relationship of ψ2 is 0□〉0□
, ψ, kuψ2, and the difference θ, −〇□ and ψ, −ψ
, is approximately 1.3α to 1.5α. Therefore, the smaller α is, the better the effective scanning period ratio becomes. Ideally, θ,=02. It is desirable to set ψ and = ψ2 so that the effective scanning areas are equal.

At that time, as shown in FIG. 4, without using the above-mentioned reflecting member 3, one plate-shaped mirror 11 is used to bring the two beams close to each other and the hologram disk 4 at the same angle.
It is conceivable to make the two beams incident on the beam, but in that case, an additional optical system 12 would be required to make the two beams parallel and narrow the distance d between them, which would complicate the structure. Moreover, when taking such a jN configuration, 2
The arrangement of the two semiconductor lasers 1 and their respective optical systems 2 is offset, resulting in a large space factor, and the installation thereof requires careful consideration.

In this point, if the reflecting member 3 is used, there is no need for an optical system consisting of a combination of lenses to convert the two beams into narrowly spaced parallel beams, and two semiconductor lasers are 1 and its respective optical systems 2 can be arranged in a distributed manner, making installation easier. Especially FIG. 5(a).

As shown in (b), the number of photosensitive drums 9 is increased.

Accordingly, the semiconductor laser 1. When the number of pairs of optical systems 2 and reflecting members 3 increases, the fact that each two semiconductor lasers 1 and their respective optical systems 2 can be arranged in a distributed manner is H! This is advantageous from an iR perspective. FIGS. 5(a) and 5(b) show the configuration of a hologram scanner according to the present invention in which four beams are scanned on four photosensitive drums 9. ing.

Furthermore, in the hologram scanner according to the present invention, one hologram disk 4 is used to scan a plurality of beams, so the structure is simpler than in the case where a deflector is provided for each beam, and it can be easily miniaturized. can be converted into

Furthermore, in a hologram scanner according to the present invention.

By making a plurality of beams incident on one hologram disk 4 at the same angle, and dividing the beams diffracted by the hologram into directions 180° different from each other by the reflection member 5, the beams are sent onto each photoreceptor drum 9. With a simple optical system configuration, main scanning of each photosensitive drum 9 can always be performed from the same direction.

In this regard, if beam scanning is performed in such a way that the direction is reversed for each main scan, the output direction of one line of serial image information that is applied to the semiconductor laser 1 and optically modulated for each main scan can be changed. It is necessary to switch it in the opposite direction.

Unfortunately, in the hologram scanner according to the present invention, when a plurality of beams are irradiated onto one hologram disk and the diffracted light is used as scanning light, a reflective member having at least two reflective surfaces with a relative angle of 90'' is required. The first beam is irradiated on one reflective surface and the second beam is irradiated on the other reflective surface, respectively, and each reflected light is made to enter the hologram disk at the same angle. The configuration has an excellent advantage in that scanning with multiple beams can be performed with a high effective scanning period rate.

[Brief explanation of the drawing]

1(a) and 1(b) are a plan view and a front view showing an embodiment of a hologram scanner according to the present invention, FIG. 2 is a perspective view of a reflecting member used in the embodiment, and FIG. 3 is a A diagram showing a beam state in which two beams are incident on the hologram surface in the same embodiment, FIG. 4 is a front view showing the configuration of another optical system that makes two beams incident on the hologram disk,
FIGS. 5(a) and 5(b) are a plan view and a front view showing another embodiment of the present invention. 1... Semiconductor laser 2... Optical system 3, 5...
Reflection member 4... Hologram disk 6... fθ
Lens 7...Mirror 8...Cylindrical lens 9...
・Photosensitive drum

Claims (1)

[Claims] A hologram disc is irradiated with multiple beams and each diffracted light is used as a scanning light, and the relative angle is 90°.
using a reflective member having at least two reflective surfaces,
A hologram scanner in which a first beam is irradiated onto one reflective surface, a second beam is irradiated onto the other reflective surface, and each of the reflected lights is incident on a hologram disk at the same angle.