DE4031418A1 - X- and Y- axis scanner for type setting equipment - uses laser scanner movable in Y direction in low junction with plate movable in X direction - Google Patents

Abstract

The scanning device has a main scanner mechanism mounted on a unit (46) which moves in the Y direction. A plate (50) which carries photo sensitive material, (not shown) moves in the X direction. Preferably, the subscanning (X direction) movement is achieved by means of a pair of rollers. Light sensitive devices (49) are fixed to the plate (50) to define relative position of plate (50) with respect to scanner (46). USE - Computer controller type setting.

Description

The present invention relates to a device and a procedure for performing a recording Light beam scanning and in particular a scanning for Perform recording on a recording medium with a larger dimension than the scanning width of the Scan recording area.

Image recording has so far been common Scanning exposure of silver halide, photographic photosensitive material or electrophotographic Photosensitive material with laser beams. Exemplary devices for this are scanners for the halftone division of photography with continuous gradation and printing presses for computer controlled type set.  

As sources used in these presses for one Different sources were used and laser beam typical examples are an argon laser, a Helium neon laser, semiconductor laser (laser diode) and the like.

Devices for performing the recording Light beam scanning contain flat bed types, Roller types and the like. Of these, all lead Light beam scanning using a polygon mirror, galvanic Mirror, a holographic disc and the movement of subsensitive photosensitive material Movement of the flatbed on which photosensitive Material is arranged, or by rotation of rollers out.

Fig. 3 shows a simple example of a device for recording on photosensitive material. The device has a laser diode 11 which emits a laser beam, a collimator lens 12 which converges the laser beam to an image-forming point, a cylindrical lens 13 , a polygon mirror 14 as a deflection device for the scanning laser beam, an fR lens 15 and the roller 17 Moving (subsampling) the photosensitive material. By rotating the polygon mirror 14 , the image-forming point of the laser beam scans the photosensitive material 16 . The roller 17 for carrying photosensitive material is rotated gradually or at a constant speed to carry out the sub-scanning, and the roller 17 is usually constructed so that the movement of the photosensitive material is carried out only in the direction of travel thereof. The width of the photosensitive material on which the recording can be carried out by this apparatus can furthermore be wider than the width which the scanning recording part with essentially the polygon mirror 14 and the fO lens 15 can scan.

Examples are as photosensitive material Offset printing plates for scanning recording are known which a silver complex diffusion transfer process to use. For pictures in book or magazine form it is necessary to produce an offset printing plate a large dimension to expose a variety of Map pages. However, none of the conventional Printing machines a scanning exposure of a number of Execute Pages.

For example, Japanese patents Kokai No. 63-1 72 691 and 63-1 97 693 proposed a process at the offset printing plates of small dimensions Be subjected to scan recording and this Printing plates together on a printing press are connected, however, this method is lower Operational effectiveness.

In addition, if the scan recording part of the Laser printing machine is large, the scan becomes larger and more expensive and next to it the diameter of the beam larger on the scanning surface, creating a Reduction in resolution is caused.  

If the scan width 18 is increased in the scan recorder shown in Fig. 3, there arises a problem that the diameter of the beam on the scanned surface is enlarged and the design of an fR lens with an accurate fR property becomes difficult. To solve these problems, the device has to be large and expensive.

Generally the scan width is relative can be reached inexpensively, 8 inches to 18 inches, with 12 inches being the most common.

In case of using a holographic disc as The deflection mechanism of the light beam is scanable width up to about 24 inches, which is more than in Case of using a polygon mirror, but it is there is a limit and it is difficult to find one Record on an aligned disk with large Dimension. There is also another one Scanning recording mechanism in which photosensitive Material is arranged in a cylindrical structure and the distance between a deflector (like one Polygon mirror) and a recording surface is kept constant, and therefore the fR lens is not required. In this case, the scanable width get big, but the production effort is high and moreover, only sheet-shaped photosensitive material be treated.

The present invention is based on the object to provide a scanning recorder which  allowed a variety of images by scanning exposure on a large size photosensitive material record without the scanning width of the To enlarge the scan recording area.

Another object of the present invention is to create a plate making process by which a variety of high definition images on one Large size offset printing plate by a small one Scanning recorder can be recorded.

Yet another object of the present invention is to create a facility that allows one Record on exact positions Recording material in the above Scan recorder, and by which is a variety of images on one Photosensitive material of large dimensions recorded can be.

In the figures shows

Fig. 1 is a diagonal view of the same Abtastaufzeichnungsapparates with a schematic view of a main part,

Fig. 2 is a plan view of a photosensitive lithographic printing plate on which images of eight pages are recorded a book by scanning by the apparatus of FIG. 1,

Fig. 3 is a perspective view of a conventional Abtastaufzeichnungsapparates,

Fig. 4 shows another relative to the to Fig. 1 different example,

FIGS. 5 and 6 further examples,

Fig. 7 to 9 further examples.

The above object of the present invention can be accomplished by a scan recorder can be released, which a scan recording area and a disc which a photosensitive material is arranged, and which is in the direction of Underscan can move back and forth, at least one of these is in the direction of the main scan can move back and forth.

The object of the present invention can furthermore be solved by a plate making process, which is the arrangement of a photosensitive comprises lithographic printing plate on a plate, which reciprocate in the direction of subsampling can move and record on the printing plate by scanning with movement of the printing plate, characterized in that the recording by Movement of the disc or the scan recording area is repeated in the direction of the main scan.

The above object of the present invention can  also solved by the following facility will. That means the back and forth movement of the photosensitive material in the direction of Undersampling is made possible by the provision of a Return roller in addition to the feed roller or by using a carrier roll, which in both Directions can rotate. Furthermore, the movement of the light beam scanning area in the direction of Main scanning allows, which makes the recording on the photosensitive material in the width direction can be repeated several times.

The above object of the present invention can further solved by a plate making process the recording on a photosensitive lithographic printing plate by scanning with a Linear movement of a reflector, which scanning light reflected, in the direction of subsampling, characterized in that the recording by multiple scans on a larger printing plate is executed as the scan width of the Scan record area in which at least one of the scan recording area or the photosensitive Material is moved.

The above object of the present invention can further by the above Scanning recorder can be solved by this is characterized that a Light beam detector on the plate is provided on which a recording material  is arranged and a direct detection of the relative Position of the disc and the scan recording area is made possible.

example

Fig. 1 is an oblique view of a main portion of an example of the scan recording apparatus of the present invention. Fig. 2 is a plan view of a photosensitive lithographic printing plate on which images of eight pages were recorded by scanning with the scanning recorder of Fig. 1.

The device according to FIG. 1 has a scanning recording area with a laser transmitter 1 , such as a laser diode in connection with a collimator lens and a cylindrical lens, a polygon mirror 2 , an fR lens 3 , a mirror 4 etc. and a plate 5 for photosensitive material . The photosensitive material (photosensitive lithographic printing plate) is arranged on the pressure plate 5 and can lie close to the plate 5 by means of a suction device. Images of a given width can be scanned on the photosensitive material by moving the platen 5 in the sub-scan direction (in the x direction) by a servo motor 6 during scan recording.

The scanning width of the scanning recording area is preferably between 8 and 18 inches, and if the width (1 in Fig. 2) of the photosensitive material is larger than the above area, exposure cannot be performed.

In the apparatus of Fig. 1, there is provided the servo motor 7 which can reciprocate the scan recording area in the direction of the main scan (direction Y), and after the completion of the first scan exposure of a given width, the scan recording area becomes the position of the next exposure by the Servomotor 7 moves and the second scanning exposure is carried out.

In this way, images from eight sides are scanned as shown in FIG . Depending on the size of the images on one page, images of two or four pages can be scanned by exposing the size at a time. This can be done by control with a microcomputer.

In the apparatus of Fig. 1, the scan recording area is allowed to reciprocate in the direction of the main scan, but the disk 5 can be reciprocated in the direction of the main scan, or both can be enabled to move in the direction of the Main scan to oscillate.

Another example of the present invention is shown in FIG . The Abtastaufzeichnungsvorrichtung of Fig. 4 includes a laser diode, a collimator lens, a cylindrical lens, a polygon mirror, a fR lens, etc., are which are not shown, and as an integral main structural member a light beam scanning section 23 included, with a device for movement in the direction the main scan, rollers 21 for carrying the photosensitive material 26 and rollers 22 for returning the photosensitive material. 25 denotes a cassette for receiving the photosensitive material.

In this apparatus, even after completion of a scanning exposure of a certain side, a light beam scanning area 23 is moved in the direction of the main scanning (direction X in Fig. 4), and then scanning return is performed after the photosensitive material 26 is returned to the original position by the return rollers 22 . By repeating this procedure, an image can be recorded on a photosensitive material which is wider than the scanning width when scanned once by the light beam scanning region 23 . Light beam scanning is performed at location 24 .

Another example of the present invention is shown in FIGS. 5 and 6. Fig. 5 is a side view of an example of an optical system in the scanning recording apparatus, and Fig. 6 is a plan view of this optical system. The light beam 36 emitted by a laser emitter 31 reaches the reflector 34 via the polygon mirror 32 and a lens group 33 . The light beam reflected by the reflector 34 forms a point image on a photosensitive layer of a photosensitive lithographic printing plate P. The light beam 37 , which is represented by a broken line in FIG. 5, shows the case in which there is no reflector. The reflector 34 can move in the direction of the optical axis of the lenses, namely in the direction of the undersampling as shown in FIG. 5. As a device for moving the reflector, for example, a servo motor with a cross roller table of high accuracy can be used, in which a ball screw is fitted.

The photosensitive lithographic printing plate P is arranged on the pressure plate 35 and can adhere to the pressure plate 35 by means of a suction device.

In the device of Fig. 6, there is provided a servo motor which can reciprocate the scan recording area in the direction of the main scan (direction X) and in the direction of the sub-scan (direction Y), and after completion of the first scan exposure becomes a given width Scanning recording area is moved to the next exposure position by the servo motor and the second scanning exposure is carried out.

A more preferred embodiment of the device according to FIG. 1 is shown in FIG. 7. The apparatus of Fig. 7 has a Abtastaufzeichnungsbereich 46 having a laser emitter 41 such as a laser diode combines with a collimator lens and a cylindrical lens, a polygon mirror 42, a fR lens 43, a mirror 44, and a scanning position detector 45 and a pressure plate 50 for Recording material which has a section 47 on which photosensitive material is arranged and a section 48 on which no photosensitive material is arranged and which is provided with the photoreceptor 49 with linearly arranged photoreceptor elements.

The recording material (photosensitive lithographic printing plate) is arranged on the pressure plate 50 and can adhere to the plate 50 by means of a suction device. During the scan recording, the platen 50 is moved in the sub-scan direction (X direction) by the servo motor 51 , and so an image of a given width on the photosensitive material can be exposed by scanning. Further, there is provided the servo motor 52 which can reciprocate the scanning recording area in the direction of the main scanning (Y direction), and after completion of the first scanning exposure of a given width, the scanning recording area is moved by the servo motor 52 to the next exposure position and the second scanning exposure can be performed.

Control of the position of the scan recording area 46 is performed by this device by the following method.

• 1) The scan recording area 46 is moved by a given amount and then scans the portion 48 where the photoreceptor 49 is present.
• 2) A time delay in the signal detection of the scanning light beam by the scanning position detector 45 and the photoreceptor 49 is checked. With reference to FIG. 8, 53 denotes a signal from the scanning position detector 45 and 54 denotes a signal from the photoreceptor 49th The time difference t of the output of these signals is obtained.
• 3) It is known from this time delay t how far the relative relationship of the positions (in the direction X in Fig. 7) of the scan recording area 46 and the cover plate 50 deviates from a given value. The scan recording area 46 is moved by an amount of this deviation to correct the relative position.
• 4) If necessary, the above procedure is repeated to keep the relative position of the disk 50 and the scan recording area 46 within a given error range.

In addition, the relative position of the disc 50 and the scan recording area 46 in the direction of the sub-scan can be obtained by comparing the amount of light received by the corresponding photoreceptor elements of the photoreceptor 49 . Fig. 9 shows examples of an output signal of each element of the photoreceptor 49th When a deviation 56 from the output signal 55 occurs at a standard position, the disk 50 deviates from the scan recording area 46 in the direction of + x and in the case of the output signal designated 57, the disk 50 deviates in the direction of -x.

The recording on an exact position can always by evaluating the timing of starting the Undersampling based on the results above be performed.

According to the present invention, an imagewise Exposure on a photosensitive material with a larger scanning width of the light beam, without increasing the scan width. Therefore, the Scanning recorder can be miniaturized and is therefore inexpensive and besides, a picture can be a high sharpness on a photosensitive material Dimension can be included.

Therefore, the present invention is particularly for Book or magazine printing with photosensitive large size lithographic printing plates as suitable for photosensitive material.

In addition, according to the present invention, a Record at exact positions on one Recording material can be carried out without any time Changes due to aging.

Claims (8)

1. A scan pickup device having a scan pickup area ( 46 ) and means for reciprocating a photosensitive material ( 26 ) in the direction of a sub-scan (X), at least one of which is capable of moving in the direction of a main scan (Y) to reciprocate, and which takes multiple shots on a photosensitive material that is wider than the scan width of the scan recording area. 2. A scanning recording device according to claim 1, characterized by a plate ( 35 , 50 ) on which photosensitive material ( 26 ) is arranged, and which can move back and forth in the direction of the subsampling ( 6 ). 3. A scanning pickup device according to claim 1, characterized by a pair of rollers ( 22 ) for reciprocating the photosensitive material ( 26 ) in the direction of the subsampling (X). 4. A scan pickup device according to claim 1 or 2, characterized in that it scans on a photosensitive material ( 26 ) by linear movement of a reflector ( 34 ) which reflects a scan beam in the direction of the sub-scan (X). 5. A scanning device according to claim 2, characterized in that it is provided with a light beam detection device ( 49 ) on the plate ( 35 , 50 ), whereby the relative position of the plate ( 50 ) and the scanning area ( 46 ) can be detected directly. 6. Method of plate making with the steps:
by performing a scan in which a photosensitive printing plate ( 35 , 50 ) is moved in the sub-scanning direction by means for reciprocating the printing plate ( 35 , 50 ), and
Repeating the scan by moving the scan area ( 46 ) or the photosensitive printing plate ( 35 , 50 ) in the direction of the main scan (Y). 7. The method according to claim 6, characterized by repeating the scanning by reciprocating a plate ( 35 , 50 ) on which the photosensitive printing plate is arranged in the direction of the subsampling (X). 8. The method according to claim 6, characterized in that the scanning recording is carried out by moving the photosensitive printing plate in the direction of subsampling by means of a pair of rollers ( 22 ) and a plurality of scanning recordings are carried out on a photosensitive printing plate ( 35 , 50 ) which are wider than that Scanning width of the scanning area is by reciprocating the photosensitive printing plate ( 35 , 50 ) in the direction of the sub-scan (X) and moving the scanning area ( 46 ) in the direction of the main scan (Y).