JPH11129531A - Image-scanning recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce costs of an image-scanning recording apparatus recording images by projecting a plurality of beams modulated on the basis of a plot signal to a heat-sensitive material mounted on an outer circumferential face of a rotating recording drum. SOLUTION: A recording head has a fiber array where a plurality of optical fibers are aligned in an array. Infrared light beams from a semiconductor laser are independently brought into each optical fiber. A line L2 of the fiber array is adapted so that it can be inclined with an optional angle θ to a movement line L1 of the recording head. A beam pitch of laser beams LB1-LB8 on the recording drum is accordingly made continuously variable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image scanning recording apparatus suitable as a manufacturing apparatus for a heat-sensitive lithographic plate used for offset printing.

[0002]

2. Description of the Related Art Conventionally, a plurality of beams modulated based on a drawing signal are scanned on a recording medium mounted on a rotating recording drum peripheral surface to thereby record an image on the recording medium. The device is well known. In such an image scanning recording apparatus, when the recording medium is a heat-sensitive material, the beam scanning unit includes an Nd-YAG laser, a beam splitter that divides a laser beam into a plurality of beams, and a multi-channel acousto-optic modulator. Those that have are common. However, the beam scanning unit having the above configuration includes:
Since the acousto-optic modulator itself is expensive and the use of the acousto-optic modulator requires a great deal of time for optical axis adjustment, there is a problem that the cost of the entire apparatus is high.

For this reason, devices using a semiconductor laser capable of directly modulating a beam as a light source have been developed. For example,
In the PEARL-Setter series (trade name) manufactured and sold by Presstek in the United States, 24 to 32 semiconductor lasers are arranged in a line in the sub-scanning direction (moving direction of the recording head) at equal intervals of 15 mm to 30 mm. It is arranged. Japanese Patent Application Laid-Open No. Hei 5-131676 discloses an image scanning recording apparatus in which a plurality of beams are two-dimensionally arranged.

According to these techniques, since a semiconductor laser can directly modulate a beam, there is no need to use an acousto-optic modulator, and the semiconductor laser itself is less expensive than a gas laser or a solid-state laser. The cost of the entire apparatus can be reduced as compared with an apparatus using an acousto-optic modulator.

[0005]

However, according to the prior art, in the method of arranging a plurality of semiconductor lasers in a line in a recording head, an optical system is required for each semiconductor laser. In addition, since it takes time to adjust the optical axis, there is a problem that the cost reduction effect cannot be expected much.

In the method described in Japanese Patent Application Laid-Open No. 5-131676, a zoom lens is required in the optical system to adjust the image resolution. There is a problem in that the structure itself becomes complicated and a large amount of time is required for adjustment.

[0007] The present invention has been made in view of such problems of the prior art, and has as its object to reduce the cost of an image scanning and recording apparatus.

[0008]

In order to solve the above-mentioned problems, the present invention provides a method in which a heat-sensitive material is attached to an outer peripheral surface of a recording drum which rotates around the center of a bottom circle, and
A plurality of semiconductors, each of which is independently modulated based on a drawing signal of a plurality of channels, from a recording head that moves along a line facing a rotation axis of the recording drum in parallel at a position separated from the outer peripheral surface of the recording drum by a predetermined distance. In an image scanning recording apparatus that records an image on the heat-sensitive material by irradiating an infrared ray from a laser, the recording head is configured such that a plurality of optical fibers into which the infrared rays are independently incident align a core center. A rotation mechanism that tilts the line of the fiber array at an arbitrary angle with respect to the moving line of the recording head, and the emission timing of the infrared light from each optical fiber, Timing control means for controlling the infrared light emitted from the optical fiber to be irradiated along a line parallel to the rotation axis on the outer peripheral surface of the recording drum. To provide an image scanning recording apparatus characterized by digit.

In the image scanning recording apparatus of the present invention, the beam pitch in the moving line direction of the recording head is continuously adjusted by tilting the line of the fiber array at an arbitrary angle with respect to the moving line of the recording head by the rotating mechanism. Can be changed. Thus, the image resolution can be changed without providing a zoom lens.

When the fiber array is tilted as described above and the emission timing of the infrared light from each optical fiber is set to be the same, the infrared light emitted from each optical fiber rotates on the outer peripheral surface of the recording drum. Irradiation is performed along a line inclined at the above-mentioned angle with respect to the axis. In the present invention, the timing is controlled by the control means, and the infrared ray emitted from each optical fiber is rotated by the rotation axis on the outer peripheral surface of the recording drum. Irradiated along a line parallel to

In the image scanning recording apparatus of the present invention, the fiber array is held in a holding member which is directly inclined by a rotating mechanism, and the holding member has a plurality of the same shapes formed at a predetermined pitch on the same surface. It is preferable that each optical fiber constituting the fiber array is independently supported by each V groove.

That is, the fiber array is tilted integrally with the holding member by tilting the holding member by the rotating mechanism. However, since the lower portion of each optical fiber is separately received by the V-groove of the holding member, the tilt angle is reduced. Even if it becomes larger, the line of the fiber array is stably held.

Further, if the pitch of the V-grooves is set to a pitch corresponding to the set core pitch (the distance between the centers of the cores of adjacent optical fibers), the optical fibers are supported by the respective V-grooves. The core pitch at is accurately maintained. If a holding member having a different V-groove pitch is prepared according to each core pitch, it is possible to easily cope with a change in the core pitch. On the other hand, conventionally, when changing the core pitch, it was necessary to use optical fibers having different outer diameters.

[0014]

Embodiments of the present invention will be described below. FIG. 1 is a schematic configuration diagram illustrating a configuration of an image scanning recording apparatus corresponding to an embodiment of the present invention.

As shown in FIG. 1, this image scanning recording apparatus comprises a recording drum 1, a recording head 2, and semiconductor lasers LD1 to LD8 to which optical fibers F1 to F8 in the recording head 2 are independently connected. And a laser modulator 3 for independently modulating the output of each semiconductor laser.

All of the semiconductor lasers LD1 to LD8 are the same laser which oscillates an infrared ray having a center wavelength of 830 nm. Such a semiconductor laser is available from the United States SDL Corporation, the United States Spectra Physics Company, the United States OPTO Corporation, etc. in a state where an optical fiber is coupled to the light emitting portion, in which case, the semiconductor laser extends from the light emitting portion of the semiconductor laser. The light incident side ends of the optical fibers F1 to F8 in the recording head 2 are connected to the tip of the optical fiber using a connector or by fusion.

As the optical fibers F1 to F8, those having a cladding diameter of 100 to 150 μm and a core diameter of 50 to 100 μm can be used. The laser modulator 3 includes an arithmetic unit 4 and
Drive circuits DR1 to DR for the respective semiconductor lasers LD1 to LD8
Eight. The arithmetic unit 4 controls the driving signals DR1 to DR8 of the driving circuits DR1 to DR8 in accordance with the drawing signals B1 to B8 of a plurality of channels and the inclination angle θ of the fiber array 21.
8 and the drive circuits DR1 to DR8 output the control signal S1
Voltage signals V1 to V8 corresponding to the respective semiconductor lasers L
Output to D1 to LD8.

The recording drum 1 is a hollow cylindrical member formed of aluminum and has a center on a bottom circle as shown in FIG. 2 (a diagram of the recording drum 1 as viewed from the direction A in FIG. 1). It is configured to rotate in the B direction. The recording drum 1 is used with a heat-sensitive material 1a mounted on the outer peripheral surface.

The recording head 2 has a fiber array 2 inside.
1 and a reduction lens system 22, and are configured to move along a movement line L1 facing the rotation axis C of the recording drum 1 at a position separated from the outer peripheral surface of the recording drum 1 by a predetermined distance K. I have.

The fiber array 21 has a plurality of optical fibers F1 to F8 of the same size, the core centers of which are aligned, and the optical fibers F1 to F8 are arranged in a line so that the distance (core pitch) between the core centers of adjacent optical fibers is the same. Here, this arrangement is held by a holding member 5 as shown in FIG.

The holding member 5 is composed of an upper member 51 and a lower member 52 which are detachably fixed by a predetermined fixing member. The lower member 52 is provided with a concave portion 53 for receiving the optical fibers in an array. The concave portion 53 is formed at a depth corresponding to the outer diameter of the optical fiber to be used, and a plurality of V-shaped grooves 53a of the same shape are formed on the lower surface thereof at a predetermined pitch (a set core pitch P1).
And the same value).

Therefore, the lower portions of the optical fibers F1 to F8 are independently supported by the V-grooves 53a and the upper portions are pressed by the upper member 51, so that the holding members 5 can be tilted as described later. Line of the fiber array 21 (line passing through the center of the core of the optical fibers F1 to F8) L2
Is stably held. Also, the V groove 53a of the holding member 5
Thereby, the core pitch P1 of the optical fibers F1 to F8 is accurately maintained. In addition, if a holding member having a different pitch of the V-groove is prepared according to the core pitch, it is possible to easily cope with a change in the core pitch.

The holding member 5 is configured to be rotatable about a longitudinal center point D of the fiber array 21 by a known rotating mechanism (not shown). By rotating the holding member 5 by this rotating mechanism, the line L2 of the fiber array 21 can be inclined at an arbitrary angle with respect to the moving line L1 of the recording head 2. As the rotation mechanism, a motor in which a gear or a belt is attached to a drive shaft is suitable.

The reduction lens system 22 includes a fiber array 21
The eight laser beams LB1 to LB8 emitted from the optical fibers F1 to F8 are reduced and focused on the outer peripheral surface of the recording drum 1 (on the heat-sensitive material 1a) with a predetermined beam system diameter. Accordingly, the laser beams LB1 to LB8 emitted from the fiber array 21 at the beam pitch P1
Are focused on the peripheral surface of the recording drum 1 at a beam pitch P2 smaller than P1.

The beam pitch P on the outer peripheral surface of the recording drum 1
2 changes by changing the angle θ between the line L2 of the fiber array 21 and the moving line L1 of the recording head 2, as shown in FIG. That is, the angle θ is θ1, θ2
(> Θ1), each beam pitch P
21 and P22, the line L2 and the line L1 are parallel (θ
= 0) (P22 <P21 <P20).

When the fiber array 21 is tilted in this manner, the emission timings of the laser beams LB1 to LB8 from each of the optical fibers F1 to F8 are assumed to be simultaneous, as shown in FIG.
As shown in the figure, the line L3 of the laser beams LB1 to LB8 irradiated on the outer peripheral surface of the recording drum 1 is inclined with respect to the line L1 at an inclination angle θ of the fiber array 21, and the respective laser beams LB1 to LB8 are recorded. The irradiation position in the rotation direction B of the drum 1 is different. The irradiation positions of the adjacent laser beams in the rotation direction B are different from each other by a distance d corresponding to the beam pitch in the rotation direction B.

Therefore, the arithmetic unit 4 of the laser modulation device 3
Is provided with a delay circuit (timing control means) for delaying the output timing of the drawing signal by a time corresponding to the distance d in the order of the drive circuits DR1 → DR8 in accordance with the inclination angle θ of the fiber array 21. The control signals S1 to S8 are output to the drive circuits DR1 to DR8.

Thus, even when the line L2 of the fiber array 21 is inclined with respect to the moving line L1 of the recording head 2, the laser beam L from each of the optical fibers F1 to F8 can be used.
B1 to LB8 are irradiated along a line L4 parallel to the line L1 (that is, a line parallel to the rotation axis C on the outer peripheral surface of the recording drum 1).

Therefore, according to this image scanning recording apparatus, the rotation member rotates the holding member 5 to incline the line L2 of the fiber array 21 with respect to the moving line L1 of the recording head 2, thereby forming the peripheral surface of the recording drum 1 Rotation axis C on
Laser beam LB1 irradiated along a line parallel to
To LB8 can be continuously changed. This makes it possible to easily change the image resolution without providing the recording head 2 with a zoom lens as in the related art.

In the above-described embodiment, the lower member 52 as shown in FIG.
Is provided with a V groove 53a.
You may use the holding member of a structure without a. That is,
Like the holding member 50 shown in FIG. 6, the concave portions 54 that receive the optical fibers provided in the lower member 52 </ b> A in an array form have a depth corresponding to the outer diameter of the optical fiber to be used, and the depth of the arrayed optical fibers F <b> 1 to F <b> 8. It may be formed with a width corresponding to the total outer diameter.

However, since the core pitch of the holding member 50 is determined by the clad diameter of the optical fiber, the V groove 5
Unlike the holding member 5 having 3a, it cannot easily cope with setting and changing the core pitch. Therefore, the V groove 53a
It is preferable to use the holding member 5 having the following.

[0032]

As described above, according to the image scanning recording apparatus of the present invention, it is possible to easily change the image resolution without providing a recording head with a zoom lens.
As a result, light loss in the optical system can be reduced, and the structure of the optical system itself can be simplified, so that the time required for adjustment can be greatly reduced, so that the cost of the image scanning recording apparatus can be reduced.

In addition, when the fiber array is held by the holding member having the V-groove, the core pitch of the optical fiber (beam pitch of the laser beam) can be easily changed in addition to the above effect. And the like.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a configuration of an image scanning recording apparatus corresponding to an embodiment of the present invention.

FIG. 2 is a schematic side view of the recording drum and the recording head of FIG. 1 as viewed from a direction A in FIG.

FIG. 3 is a front view showing a fiber array holding member used in the image scanning recording apparatus of FIG. 1;

FIG. 4 is an explanatory diagram for explaining a beam pitch on a recording drum according to an angle between a line of a fiber array and a moving line of a recording head.

FIG. 5 is an explanatory diagram illustrating an operation of a delay circuit that operates when the fiber array is tilted.

FIG. 6 is a front view showing another embodiment of the holding member.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 recording drum 1a heat-sensitive material 2 recording head 21 fiber array 3 laser modulator 4 arithmetic unit (timing control unit) 5 holding member 50 holding member 53a V groove B recording drum rotation direction C recording drum rotation axis L1 recording head movement Line L2 Line of fiber array L4 Line parallel to rotation axis DR1 to DR8 Drive circuit F1 to F8 Optical fiber LD1 to LD8 Semiconductor laser LB1 to LB8 Laser beam (infrared ray)

Claims (2)

[Claims] 1. A heat-sensitive material is mounted on the outer peripheral surface of a recording drum that rotates about the center of a bottom circle, and the heat-sensitive material is
A plurality of semiconductors, each of which is independently modulated based on a drawing signal of a plurality of channels, from a recording head that moves along a line facing a rotation axis of the recording drum in parallel at a position separated from the outer peripheral surface of the recording drum by a predetermined distance. In an image scanning recording apparatus that records an image on the heat-sensitive material by irradiating an infrared ray from a laser, the recording head includes a plurality of optical fibers, each of which independently receives the infrared ray, having a core center aligned. A rotation mechanism that tilts the line of the fiber array at an arbitrary angle with respect to the moving line of the recording head, and the emission timing of the infrared light from each optical fiber, Timing control means for controlling the infrared light emitted from the optical fiber to be irradiated along a line parallel to the rotation axis on the outer peripheral surface of the recording drum. An image scanning recording apparatus, comprising: 2. The fiber array is held in a holding member that is directly inclined by a rotating mechanism, and the holding member has a plurality of V-grooves of the same shape formed at a predetermined pitch on the same surface. 2. The image scanning and recording apparatus according to claim 1, wherein each optical fiber constituting the fiber array is independently supported in each V-groove.