JPS59157612A - Plural-laser-beam scanner - Google Patents

Abstract

PURPOSE:To perform the simultaneous deflection of plural beams through a simple structure without requiring any complicate adjustment by providing concentrically plural arrays of holograms different in angle of deflection on a hologram disk and deflecting the beams, in each array. CONSTITUTION:When three laser beams are scanned, the beams from a laser diode array 15 are deflected by a hologram scanner 16. Holograms consist of hologram lenses arrayed on three concentric circles A-C, whose deflection angles and image-formation positions are different, in each hologram array, corresponding to the hologram arrays A-C to obtain scanning lines of the same length at different positions. Therefore, this photoscanner eliminates the need to uniform the optical path length of every beam, and the respective beams are guided to photosensitive bodies 11-13 by reflecting mirrors 19-21 to record images in the same size on the respective photosensitive bodies.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an optical scanning device using a hologram disk as an optical deflector, particularly an optical scanning device in which a plurality of beams are scanned by one optical deflector. Regarding equipment.

(Prior Art) In order to enable multicolor printing in laser printers and the like, attempts have been made to scan multiple laser beams using a single rotating polygon mirror. Figure 1 is 0
As an example, an optical path diagram after a rotating polygon mirror is shown when three beams are used. The three beams, which are slightly shifted from each other and are deflected by the same reflecting surface of the rotating polygon mirror 1, are reflected by the mirror 2.3.4 onto the photoreceptor 11, and then reflected by the reflecting mirror 5.
．． 6.7 on the photoreceptor 12, and the reflecting mirror 8.9.
．． 10 to scan over the photoreceptor 13. If the three beams are energized by red, blue, and yellow surface edge signals, and red and yellow toners are used, and the three beams are overlapped and transferred, a three-color printing V group can be obtained.

In this example, only one f-theta lens 14 is required, but if each beam is polarized by a different O-plane of the rotating polyhedron, then each beam can be equipped with a different f-theta lens. In an optical scanning device, the deflection angle of the beam by the rotating polygon mirror must be the same for all beams. Therefore, if you try to equalize the size of the image by each beam, that is, the scanning range, It is necessary to make the optical path lengths the same. For this reason, it becomes necessary to arrange a large number of reflecting mirrors in the optical path, and it is troublesome to adjust the alignment between multiple beams.
It is also 11 degrees lower than the 〇 match. Further, there arises the problem that it is difficult to increase the number of beams.

(Purpose of the Invention) This invention □ uses a hologram scanner in which hologram lenses with different scanning and focusing characteristics are arranged concentrically on a rotating disk. The purpose of this invention is to obtain an optical scanning device that can be used for scanning.

(Structure of the Invention) A conceptual diagram of the optical scanning device (1) of the present invention implemented (I2) is shown in FIG. 2, and the arrangement of holograms on the hologram disk is shown in FIG.

In the case of scanning with three laser beams, the beam from the array 15 consisting of three laser diodes is deflected by the hologram scanner 16, but the holograms are arranged in 3* concentric circles A, B as shown in FIG. , C, whose deflection angles and imaging positions are A, B corresponding to the hologram arrays A, B, , C.

As shown in FIG. 4, each hologram array is designed to obtain scanning lines of the same length at different locations. Therefore, in the case of this optical scanning device V), there is no need to make the Q optical path lengths the same for each beam, and the deflected beams pass through reflection mirrors 19, 20, 2, and 18 respectively.
1 to the photoreceptors 11, 12, and 13, and the same size of iron is recorded on each photoreceptor.

FIG. 5 shows another orientation for &6, in which the original 22 is collected by a two-color image sensor 23 and directly input as a modulation signal for each beam of a laser diode 24 which emits two laser beams. (by two beams), photoreceptor belt 2
6, electrostatic latents of different colors are formed, and each S iron is removed by a black remover 27 and a remover b 28, respectively, and superimposed by two rotations of transfer in a transfer unit 29. ,2
You will get a color copy.

Figure 6 shows another implementation orientation of the hologram scanner, and if we change the scanning width of the hologram array, E, F, and G as shown in Figure 6(a), we can use it for beam deflection. By changing the trunk to D%E, F, and G, it is possible to change the magnification of the size. Also, as shown in the same figure (b), 1 in the circumferential direction.
By changing the scanning width between H2I and 1% in advance, and changing the timing, the hologram for artistic use can be adjusted to H2I.
, I and 1%.

Normally, in digital copying, the line accuracy is reduced to 14 by thinning out the dots and the magnification is changed. Other magnification changes complicate information processing. However, if a scanner like the one shown in Figure 6 is used, such restrictions on variable @ magnification are eliminated. Therefore, by combining 1) dot 0 thinning and one-stage magnification change as shown in Figure @6, four-step magnification change like that of a lower garment is possible with only simple signal processing.

(Effect of the invention) As mentioned above, this invention has a
Multiple rows of holograms with different deflection angles are arranged in concentric circles, and each row is designed to deflect an individual laser beam, which does not require complicated R-hardness such as making the optical path length of each beam the same. Simultaneous deflection of multiple beams with a simple structure &[
can be obtained.

This feature becomes even greater when the number of beams is increased to 3.4, as it is possible to simultaneously scan with one scanner by simply increasing the number of hologram rows. In addition, there are remarkable effects in that selection of the hologram array, simultaneous scanning of a plurality of beams, and variable magnification can be easily performed.

[Brief explanation of drawings]

FIG. 1 is an optical path diagram of a known multiple beam scanning device, FIG. 2 is an optical path diagram of an embodiment of the optical scanning device of the present invention, FIG. 3 is a top view of the hologram scanner, and FIG. 4 is a scanning diagram thereof. An explanatory diagram of the angle and the connecting position, Fig. 5 is an applied version of the optical scanning device of the present invention, and Fig. 6 is a diagram of the practical implementation of the Ike Q-gram scanner with rotating polygon mirrors 2 to 10 and 17 to 21.
:Reflector 11.12.13.26:Photoreceptor 16.2
5: Holoscanner 15.24: Laser diode
22: Manuscript 23: Image sensor 27. 28 Recorder 29: Transcription unit Patent applicant Ricoh Law Company - Dispatch agent Patent attorney Aya Sato (and 1 others)
Figure 2

Claims (1)

[Claims] In a laser beam scanning device in which holograms are arranged concentrically on a rotating disk and a laser beam is deflected and scanned by the holograms, a plurality of groups of holograms having different deflection angles are arranged on the same rotating disk, and each of the plurality of beams is is deflected and scanned by one or zero of the plurality of groups.