JPH0367511B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a timing signal generating device for an optical printer when scanning an optically modulated laser beam to form a latent image on the surface of a photoreceptor.

[Conventional technology]

As this type of laser recording device, one shown in FIG. 1 has been proposed. In the figure, 1 is a laser light source, and 2 is an example of a laser beam for applying optical modulation to the light beam from the laser light source 1 via a half mirror 3.
AOM (acousto-optic modulator) 4 is a mirror that reflects the light transmitted through the half mirror 3 as it is. 5 is a rotating polygon mirror (hereinafter abbreviated as polygon mirror) for reflecting the laser beam output from the laser light source 1;
One side scans a recording material (photoreceptor) 7 with modulated light through a lens 6, and the other side directs a laser beam onto a slit 10 via mirrors 8 and 9.
11 is a concave mirror divided into n parts, and the slit 10
The laser beam that has passed through is reflected and focused on a light receiver 12. 13 is an amplifier; 14 is an adder; 15 is a waveform shaper that shapes the output signal of the amplifier 13;
16 is an information source that is input to the AOM driver 17.

Next, the operation will be explained. One of the laser beams output from the laser light source 1 is incident on the AOM 2 via the half mirror 3, where it is applied to the recording material 7.
Light modulation is applied to the image data. On the other hand, the laser spot transmitted through the half mirror 3 is reflected by the mirror 4 as a timing clock light beam, and is converted into a scanning light beam of a predetermined width by the polygon mirror 5 to form a timing clock for recording. You will be led to slit 10. The scanning light passing through this slit 10 is divided into n parts (n=2,
3, 4...) The light is focused on each light receiver 12 by the exposed concave mirror 11, and an electric signal (timing clock) is output. This output signal is sent to the subsequent amplifier 1.
3 and an adder 14, and is supplied to an AOM driver 17 via a waveform shaper 15. The AOM driver 17 synchronizes the data input from the information source 16 with this timing clock signal,
It is configured to give

However, the problem remained that the scanning light was dispersed at the joining surface of the two (n=2, 3, 4...) concave mirrors, as shown in Figure 2, and the amount of light incident on the receiver was reduced. . Furthermore, the same applies if there is dirt or scratches on the slit surface, for example, at the time shown in Figure 3.
When the beam a at time t ₀ passes through the coupling surface of the concave mirror, it decreases as shown in A and exceeds the threshold value TH, causing a problem that the clock in B is missing as the timing clock signal in b.

[Object of the present invention]

The present invention was made to eliminate the above-mentioned drawbacks, and the reduction in light intensity due to dust, scratches, etc. on the joint surface or slit surface of a concave mirror divided into n parts (n = 2, 3, 4...) An object of the present invention is to provide a timing signal generating device for an optical printer that automatically corrects the timing signal and is accurate.

[Example of the present invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In FIG. 4, the same parts as in FIG. 1 are designated by the same reference numerals. In FIG. be.

Next, the operation of the present invention will be explained. First, a laser beam emitted by a laser light source 1 is divided by a half mirror 3 into a recording beam and a timing clock generation beam. Furthermore, the timing clock generation beam is split into two beams by a half mirror 18. When the two beams scan the slit 10,
The set angles of the half mirror 18 and mirror 4 are adjusted so that no phase difference occurs for each arbitrary slit, and the pitch is set to be an integral multiple of the grating pitch of each slit. A recording beam modulated via an AOM 2 (described later) and two timing clock generation light beams transmitted through a half mirror 3 and further reflected by a half mirror 18 and a mirror 4 are simultaneously deflected by a polygon mirror 5. be done. One of the recording laser beams scans the recording material 7 in the main scanning direction through the lens 6, and the other timing clock generation beam is transmitted to the mirrors 8, 9, the slit 10, and the diffuser plate attached to the slit 10. n concave mirrors 11 (n=2, 3, 4, . . . ) are scanned through the mirror 19. The two timing clock generation light beams are condensed by each concave mirror 11 constituting a condensing section, and a light receiver 12 disposed opposite each concave mirror.
receives light. The output signals of each photodetector are amplified by an amplifier 13, added by an adder 14, and outputted to a waveform shaper 15 as a timing clock. The timing clock whose waveform was shaped by the waveform shaper 15 is
Sent to AOM driver 17. The AOM driver 17 sends data from the information source 16 to the AOM 2 in synchronization with the timing clock.
AOM2 performs optical modulation according to the data.

Further details will be given below with reference to FIGS. 5 and 6. For example, if beam A passes through the joint of the concave mirror at time t ₀ in FIG. 5, the beam A will be dispersed at the joint as shown in the figure, so the output signal of the photoreceiver 12 will be as shown in FIG. 6a. The amount of light decreases as shown in (a). On the other hand, beam B has the same phase as beam A while maintaining a pitch that is an integral multiple of the slit pitch.
Since the light is reliably received by the light receiver as shown in FIG. 5, the output at time _t0 is as shown in FIG. 6b. Then, at time _t1 , when the beam B passes through the coupling surface of the concave mirror and the light intensity decreases as shown in FIG. 6b, the beam A obtains an output as shown in a. Thus, by adding the outputs of beam A and beam B, it is possible to obtain an accurate timing clock as shown in c.

The above description has been made of the decrease in the amount of light at the coupling surface of the concave mirror, but it is also possible to automatically correct the decrease in the amount of light due to dust, scratches, etc. on the slit surface in the same way. Further, the number of beams to be scanned is not limited to two, but may be a plurality of beams.

[Effects of the present invention]

As described above, according to the present invention, a plurality of light beams for timing clock generation are provided, and each light beam is set so that a phase difference does not occur. It is possible to automatically correct the decrease in the amount of light, and as a result, an accurate timing clock for recording can be obtained, resulting in excellent effects such as being able to perform faithful recording.

[Brief explanation of drawings]

Figure 1 is a block diagram of the main parts of the optical system and electrical system of a conventional optical recording device, and Figures 2 and 3 are light reflection diagrams and light reception of the concave mirror coupling surface that identify the problems of the conventional system. FIG. 4 is a block diagram showing the optical system and electrical system of an optical recording device according to an embodiment of the present invention, and FIG. 5 and FIG.
The figure is a light reflection diagram of the concave mirror coupling surface according to the present invention and a characteristic diagram of the light receiver. 1... Recording laser light source, 2... AOM, 3,18
...half mirror, 4,8,9...mirror, 5...polygon mirror, 6...scanning lens, 7...recording material, 1
0...slit, 11...concave mirror, 12...light receiver, 1
3...Amplifier, 14...Adder, 15...Waveform shaper,
16...Information source, 17...AOM driver, 19...
Diffusion board.

Claims (1)

[Claims] 1. A large number of slits are arranged on the scanning optical path of the timing clock light beam deflected by the optical deflection means, and a plurality of beams of the same phase having a pitch that is an integral multiple of the pitch of the slits are directed to the optical deflection means. The slit is scanned in parallel, and the plurality of beams transmitted through the slit are aligned in the scanning direction of the timing clock light beam (n=n).
Each timing clock is reflected by the light condensing section (2, 3, 4...) and obtained by n (n = 2, 3, 4...) light receivers arranged one-to-one with the condensing section. 1. A timing signal generating device for an optical printer, characterized in that a signal for each clocking light beam is applied to an adder, and one timing clock is obtained from the output signal of the adder.