JPS60111570A - Optical rotary printer - Google Patents

Abstract

PURPOSE:To change the number of halftone lines simply and efficiently when the halftone screen plate is manufactured by driving continuous (n) light sources which correspond to respective light sources of respective irradiation parts, and by setting the optical beam diameter on the recording materials of the respective light sources and the subscanning to the prescribed value for a main scanning 10. CONSTITUTION:A platen 2 is arranged at the frame of an optical rotary printer, and a rotary disk 4 is arranged at an arm 3. A laser beam irradiation window 19 is provided at a circumference face 13 of the disk 4 at equal intervals, and a laser beam irradiation part 20 is provided at the inside. Recording paper 16 is arranged in the cylindrical shape around the rotary shaft so that the paper will be opposite to the irradiation part 20. Either of the supporting means of the irradiation part 20 or the recording paper 16 is shifted in the direction of the rotary shaft and in the direction that the position of the irradiation beam is separated on the recording paper 16. The optical beam diameter on the recording paper 16 is set as 360l/360-mnthetamum, and the subscanning is set as lmn/360-mntheta mum for the main scanning 1 deg.. When the halftone screen plate is manufactured, the number of halftone lines are changed simply and effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical rotary printer for recording information on a recording material using a light beam modulated with an information-carrying signal, and more particularly, It is a light source on a light source support that rotates relative to the recording material.

(Prior art) In optical recording devices that record information using a light beam, a light beam modulated by a signal carrying information is deflected using an optical deflector such as a galvanometer mirror or a polygonal rotating mirror. A system in which information is recorded on a recording material by two-dimensionally scanning the recording material that is sensitive to the beam has been widely known.

However, this type of apparatus has disadvantages in that it is expensive to manufacture and cannot record high M image power and high brightness, and in recent years, optical rotary printers have been attracting attention. An optical rotation link is, for example, a recording material supported on the circumferential surface of a tram-shaped platen that rotates for main scanning, a light beam irradiation system provided close to the platen circumferential surface, and a light beam irradiation system installed in the vicinity of the platen circumferential surface. The system is moved in the direction of the platen rotation axis to perform sub-scanning.

As a light source for such an optical rotary printer, it is advantageous to use a semiconductor laser light source because it is compact and can generate a light beam having the same spatial coherence as a melon and a high spectral line III degree. Note that the term "optical rotary printer" in the present invention includes both types of printers, one in which the light source side is fixed and the recording material is rotated, and one in which the recording material is fixed and the light source side is rotated.

The inventors of the present invention have already developed a laser rotary printer that is capable of high-resolution, high-luminance recording, and can also record information at high speed, and have filed a patent application for it in Japanese Patent Laid-Open No. 57-59.
No. 33).

This laser rotary printer is equipped with a laser beam irradiation system consisting of a semiconductor laser that irradiates an outward laser beam and a condensing lens on the circumferential surface of a rotating body rotated by a rotating means. The rotating body is supported around the rotating body concentrically with the rotating body, for example, the rotating body is formed to be movable in a direction parallel to the rotation axis of the rotating body, and the laser beam irradiated from the laser beam irradiation system is rotated. The recording material is scanned two-dimensionally by the rotation of the body and the relative movement of the rotating body and the recording material in the axial direction of the rotating body. Among them, for example, a plurality of irradiation parts in which the laser beam irradiation system is fixed with their centers aligned in the circumferential direction are arranged at equal intervals on the circumferential surface of the rotating body, and the centers of each irradiation part are located on a common circumference. A plurality of semiconductor rays are arranged in each irradiation section, and each semiconductor ray is fixed in a posture such that it is shifted at equal intervals in the rotation axis direction d5 of the irradiation section rotor and in the circumferential direction on the recording material. Something like this is actually used. With such an apparatus, for example, a plurality of adjacent scanning lines can be formed simultaneously by driving each semiconductor laser of each irradiation section with a drive signal modulated by an R image signal.

Incidentally, an electric mesh plate forming method has recently come into use as a method for recording continuous tone originals as a printing grid. Compared to conventional optical and physicochemical methods, this method is economical because it does not use consumable parts and requires smaller equipment, has a simpler processing process, and is stable in terms of performance. This is because it has many advantages such as.

An example of such an electrical mesh plate formation method is to store a halftone dot pattern in a memory device in advance, and then scan a continuous tone original to generate a halftone pattern signal corresponding to the density of each pixel. It is known that a pattern signal read from a memory is read out and an exposure light source is driven based on the pattern signal to perform scanning exposure on a recording material to make a mesh plate.

The above-mentioned halftone dot pattern is formed by a plurality of dots in common, and the larger the number of exposed dots, the higher the document temperature.

When making plates for such mesh plates, if you use an optical rotary printer like the one described above, you can expose many layers at once, and even use one or two irradiation system groups. This is convenient because signal processing can be simplified by assigning one person to be responsible for exposing one halftone dot.

By the way, when making a halftone plate, it is frequently necessary to change the number of dots in a halftone pattern, or in other words, to change the number of halftone lines.

In such a case, the number of mesh lines may be changed by increasing or decreasing the number of light sources to be driven among the light sources of each irradiation unit in the optical rotary printer described above.

When it is necessary to reduce the number of mesh lines, the number of light sources to be driven is increased, and conversely, when it is necessary to increase the number of mesh lines, the number of light sources to be driven is decreased. However,
In this case, if the number of light sources to be driven is simply increased or decreased, the beam spots 1 to 1 on the recording material may overlap in the sub-scanning direction or be separated unnecessarily, and the pitch of the beam spots will not be uniform.

Therefore, in cases where pitch uniformity is extremely important, such as when making a wire plate by forming one halftone dot pattern using two beam irradiators, it is impossible to obtain a satisfactory image. There's a problem.

In order to solve this problem, it is necessary to finely adjust the optical axis of the light source of each irradiation section in the sub-scanning direction according to the number of driving light sources, so that the recording material formed by the light source of each irradiation section can be The pitch of the upper beam baffle may be made uniform in the sub-scanning direction.

However, adjusting the position of the optical axis of the light source is extremely time-consuming work, and it is not recommended for work efficiency to adjust the position of the optical axis of all the light sources of each irradiation system group every time the number of mesh lines is changed. I also don't like it.

In addition, if there is an urgent need to record the information, please do the work described in (a) above in advance. There's a problem.

(Object of the Invention) In view of the above circumstances, it is an object of the present invention to provide an optical rotary printer that can easily and efficiently change the number of mesh lines, especially when making a mesh plate.

(Structure of the Invention) The optical rotary printer of the present invention has m light beam irradiation parts each having a plurality of light sources arranged outwardly in the direction of the forming object around the rotation axis. a group of light beam irradiation systems disposed in the group; recording material support means for supporting a recording material formed in a cylindrical shape around the rotation axis so as to be close to and opposite to the group of light beam irradiation systems; Either one of the light beam irradiation system group or the recording material supporting means is rotated in the main scan around the rotation axis at high speed, and one of the two is rotated in the direction of the rotation axis and by the light beam from the light source. The light beam spots formed on the recording material are separated from each other J
: A main scanning drive means and a sub-scanning drive means for moving the light source in the vertical direction in the sub-scanning direction. The light beam irradiation portion is arranged so as to be shifted by μnL in the direction of the rotation axis, and the light beam irradiation portion is centered around the rotation axis (=).
and the corresponding light sources of each of the irradiation sections are arranged so as to coincide with each other in the rotational direction of the rotation axis, and the corresponding continuous light sources of the light sources of each of the irradiation sections are
Drive the light sources, set the light beam diameter of each light source on the recording material to mn, and set the sub-scan to 1° of the main scan.5. Aya, -
It is characterized by being set to μm.

Here, the corresponding light sources between each illumination system refer to the corresponding light sources, such as the light source located on the rightmost side of each illumination system, or the light source located on the leftmost side of each illumination system. .

By the way, the light beam diameter is m-1"-μm, and one run is 360-μm.
mnθ mn The sub-scanning feed relationship for 1° scan is -971,1717μ
The reason for setting m is explained below using FIGS. 1 and 2.

Figure 1 shows the positional relationship between the light sources of the first and second irradiation sections, and Figure 2 shows the adjacent beam spots formed on the recording material by the eight light sources in Figure 1. This is a schematic diagram. Here, the beam spots 1 to 1 formed by the light source 1A are represented by corresponding overlapping symbols such as IA' (=j
It is written down. At t3, for convenience, it is assumed that four corresponding light sources are turned on in each irradiation unit. In addition, the sub-scanning feed (sub-scanning performed during 1° main-scanning rotation) is Sμ
nL/' degrees, and the light beam spot diameter on the recording material is RμnL. In addition, in each irradiation section, each light source is spaced at θ° intervals around the rotation axis, and the corresponding light sources between each irradiation section (
For example, 1A and 2A) are arranged at intervals of □ degrees). In order for the light sources arranged as shown in FIG. 1 to form beam spots that touch each other in the sub-scanning direction as shown in FIG. 2 on the recording material L, first,
For example, IA' and 18' must be formed so that they are in contact with each other, and sub-scan feed must be performed by R-9J (μIrL) while main-scan rotation is performed by θ°.
θ5=R Just in case...1) Also, for example, if the distance between the centers of IA' and 2A' is 4R
It must be formed so that the main scanning rotation is 3
While GO/m (degrees) is being performed, the sub-scanning feed is 4R (μm).
) Because it needs to be done, it is hard us = 4 R・
・・・・・・・・・2) If the number is 4 each, 1°
The sub-scan is performed while the main scan is rotated 90. -me μm, set the heem spot on the recording material at -J--um, 90
-mO is good. In addition, when the number of light sources driven by each irradiation section is 11, the sub-scanning performed during the 1° main scanning rotation can be calculated as follows:
- μm, the diameter of the beam slit on the recording material is 1 m.
It may be set to nμnL.

3601θ (Effects of the Invention) As described above, the optical rotary printer of the present invention adjusts the diameter of the light beam and the main scanning direction according to the number (1) of light sources of each light beam irradiation unit that scans the recording material. The sub-scanning feed speed is changed to a value that prevents adjacent beam spots from overlapping or being spaced apart from each other on the recording monthly basis, i.e., the beam spot diameter on the recording material. 360-mn
0 μm, the sub-scanning feed rate for 1° main scanning is set to the angle at which the light sources adjacent to the width part look at the rotation axis, and nl is the number of irradiated parts, so that a mesh plate is made by the light beam. In such a case, even if the number of m lines is changed, it is possible to obtain a desired image according to the number of mesh lines. Further, there is no need to adjust the optical axes of the light sources according to the number of light sources to be driven, and work efficiency is extremely high. It goes without saying that the optical rotary printer according to the present invention can be used not only for halftone images as shown in (a) above, but also for continuous W4 images.

(Embodiments) Hereinafter, embodiments of the present invention will be described using the drawings. FIG. 3 is a schematic perspective view, not showing one embodiment of the optical rotary printer according to the present invention.

As shown in the figure, the optical rotary printer of the present fM mode is a laser rotary printer, and includes a platen 2 with a curved upper surface fixed on a tabletop mount 1, and an arm 3 that supports the platen 2.
It has a rotating disk 4 supported above. The arm 3 has two silk rod bearings 5, 6 on its back, and two parallel rods 7.8 fixed to the frame 1 are passed through these rod bearings 5, 6, respectively. Therefore, the arm 3 is supported by these two Rondo doors 8 and can slide in the direction of the arrow in the figure. Rod bearings 5, 6 of arm 3
A nut 9 is fixed between them, and this nut 9 is threaded onto a screw rod 11 which is rotated by an arm moving motor 10. Therefore, when the arm moving motor 10 is driven and the screw rod 11 rotates, the arm 3 moves in the direction of the arrow.

FIG. 4 is an enlarged view of the rotary disk 4 supported by the arm 3 and the platen 2, or as clearly shown in FIG. The support surface 12 is formed to be concentric with the circumferential surface 13 of the rotating disk 4. This recording paper support surface 1
A recording paper suction hole 14 is provided at an appropriate position of 2.
This recording paper suction hole 14 is connected to the suction side of a vacuum pump 15 built into the apparatus through piping (not shown). Therefore, recording paper 1 that records information by being exposed to a laser beam
When the recording paper 1G is placed at a predetermined position on the recording paper support surface 12 of the platen 2 and the vacuum pump 15 is rotated, the recording paper 1G is firmly fixed on the recording paper support surface 12.

The above-mentioned rotating disk 4 is made up of a shallow cylindrical member with a bottom made up of the circumferential surface 13 and the bottom surface 17 and a cover plate 18 attached thereto. Four oval laser beam irradiation windows 19 are provided on the circumferential surface 13 at equal intervals on the same circumference.

Inside each of these laser beam irradiation windows 19, a laser beam irradiation unit 20 that emits a laser beam outward from the laser beam illumination window 19 is fixedly disposed on the bottom surface 17. There is. As schematically shown in FIG. 5, these four laser beam irradiation units 20 each have four laser beam irradiation systems 21 centered around one laser beam irradiation unit 20 in the circumferential direction. It becomes fixed. All four laser beam irradiation units 20 are of the same type, and therefore, the mounting center of the laser beam irradiation system 21 is located on the common circumference among the four laser beam irradiation units 20.

That is, all 1G laser beam irradiation systems 21 are arranged on one common circumference. Each C-9 beam irradiation system 21 includes a semiconductor laser 23 supported by a cylindrical support 22 and a condenser lens 24 . As shown enlarged in FIG. 6, each semiconductor laser 23 is supported within the support body 22 by a fine adjustment screw 25.
5, the optical axis can be independently swung in the direction of arrow B in FIG. As shown in FIG. 7, the optical axes of the four laser beam irradiation systems 21 in each laser beam irradiation section are connected to the second laser beam irradiation system 2.
The optical axis [1] of the first laser beam irradiation system 21a is aligned with the mounting center C of the irradiation system, and the optical axis La of the first laser beam irradiation system 21a is aligned on the recording paper 1G from the mounting center C to the right direction of arrow A in FIG. 12μm
1. The light IMLQ of the third laser beam irradiation system 21c is also 12 μm to the left from the mounting center C on the recording paper 16, and the optical axis ld of the fourth laser beam irradiation system 21d is 12 μm to the left from the mounting center C.
It is adjusted so that it deviates by 24 μm to the left. Therefore, the four laser beams emitted from each laser beam irradiation section 2o are irradiated onto the recording paper 1G at intervals of 12 μnL in the moving direction of the rotating disk 4 (in the direction of the arrow in FIG. 1). .

Furthermore, each laser beam irradiation system 2a in each laser beam irradiation section 20 is oriented 5 times around the rotation axis of the rotating disk 4.
They are arranged so that they are spaced at intervals of °.

Note that the beam spots simultaneously recorded on the recording paper 1G by the corresponding laser beam irradiation systems 21 between the respective laser beam irradiation units 20 are arranged on a common circumference centered on the rotation axis of the support body 22. Further, the heath mark is arranged so as to be shifted by a fixed interval in the direction of rotation of the rotary shaft, for example, so that the irradiation position on the recording paper is shifted by 3500 spots. Therefore, it is necessary to input a corresponding drive signal to each laser beam irradiation system.

The rotary disk 4 having the laser beam irradiation section as described above is rotated in the direction of the arrow in FIG. 3 by an outer rotor motor 2G fixed to the center thereof.

A secondary printed coil 27 is fixed to the inside of the cover plate 18 of the rotary disk 4, and a primary printed coil 29 is fixed to the inside of the bearing part 28 of the arm 3. A high-frequency current for driving a semiconductor laser modulated by a signal carrying information to be recorded is supplied to the primary printed coil 29 on the fixed side through a cable 31 suspended from a wire 30. This high frequency current is applied to the fixed primary print 1 coil 29 and the rotating secondary print 1 to coil 27.
It is transmitted to the rotating disk 4 side without contact by electromagnetic coupling between the two. Rotating disk of current for driving semiconductor laser 4
The supply may be carried out using slip links and brushes, but a method using electromagnetic coupling is advantageous because it does not generate noise and does not adversely affect surrounding electric circuits. Current is also supplied to the outer rotor motor 2G that rotates the rotary disk 4 using the cable 31 described above.

Detection of the starting point of the rotating disk 4 is performed by a rotary encoder fixed within the rotating disk 4 and a detection section (both not shown) fixed to the arm 3. The moving portion of the rotary dinuque 4 is covered by a cover 32, as shown in FIG. If the cover 32 is made of a material that allows visible light to pass through, which is insensitive to the recording paper 1G, it is convenient because the operation of the apparatus can be checked from the outside.

By the way, this device has a control unit 33, which controls the number of light sources to be driven, main scanning rotational failure, sub-scanning feed speed, beam spot diameter, etc. based on the settings on the front panel. Herol. The control unit 33 also has a memory device OL, and for example, according to the input value of the number of light sources to be driven, an appropriate scanning speed, beam spot diameter, etc. can be adjusted based on a pre-stored training formula. A control signal corresponding to the divided value is sent to each drive section. This memorized calculation formula is 1° main −
This is the number of irradiation systems 21 driven in the system irradiation unit 20.

Incidentally, FIG. 8 shows an example of one halftone dot pattern when the above-mentioned apparatus is used to form a mesh plate, particularly a 45° mesh plate in which halftone dots are arranged in a 45° direction with respect to the main scanning direction. In reality, such halftone dot patterns are formed continuously, but in FIG. 8, only one halftone dot pattern is shown for convenience of explanation.

This halftone dot pattern is formed by two adjacent laser beam irradiation parts.Here, for convenience, the area formed by the first laser beam irradiation part is the first zone, and the area formed by the second laser beam irradiation part is formed by the second laser beam irradiation part. An imaginary line is drawn in FIG. 8 to divide the area into the second zone. Note that the main scanning direction is the arrow F1 direction in the figure, and the sub-scanning direction is the arrow F2 direction.

The forming operation of this halftone dot pattern is performed by first forming a spot Jl using the first Lurie beam irradiation system in the first laser beam irradiation section, and then forming a spot Jl using the second laser beam irradiation system.
, J2, and K2, followed by spots 1''3 to L3 by the third laser beam irradiation system, and then the fourth spot.
After the first zone is formed by irradiating spots of 04 to M4 with the laser beam irradiation system, the second zone is formed in the same manner by each laser beam irradiation system of the second laser beam irradiation section. Note that these laser beam irradiation systems are driven by different digital modulation signals to light up the beams. The above operation is performed when all the spots of this halftone dot pattern are irradiated, and in this case, the halftone dot a
degree is highest. In reality, a digital modulation signal is input so that some or all of the aforementioned spots are irradiated depending on the degree a to be expressed.

By the way, in general, when forming such a pattern, adjacent spots are often arranged with equal width, or in order to increase the density of spots in one halftone dot, the method shown in Fig. 8 is used. It is desirable that the slats 1 to 1 which are adjacent to each other in the longitudinal and lateral directions of the sea urchin are arranged so as to be in contact with each other.

Therefore, for example, it is desirable that the slots J1 to J8 formed by eight laser beam irradiation systems are arranged so as to touch each other on a straight line facing approximately the sub-scanning direction (approximately the direction of arrow F2). In this apparatus, the position of the laser beam system, beam diameter, speed of sub-scanning relative to main scanning, etc. are adjusted to values that can achieve the purpose.

However, in the process of screen plate making, the number of mesh lines is frequently changed. That is, in this case, the number of spots within one halftone pattern is changed.

For example, in each laser beam irradiation section, driving of the fourth laser beam irradiation system (the irradiation system arranged at the last stage in the main scanning direction) is stopped, and a halftone dot pattern as shown in FIG. 9 is formed. Consider the case where the number of thin lines is changed by .

In this case, if the spots arranged in the vertical and horizontal directions are arranged so as to touch each other, for example, six spots 11 to I3 and In this case, if the pattern shown in Fig. 8 is scanned under the same conditions as when forming the pattern shown in Fig. There will be a gap of one spot.

In order to eliminate such gaps, the optical axis of each laser beam irradiation system can be adjusted using the fine adjustment screw 25 described above, but this adjustment requires a great deal of time and effort.
If you have to make this adjustment every time you change the thin line, it will reduce your work efficiency.

Therefore, in the apparatus of this embodiment, as described above, the beam diameter and the speed of the sub-scanning with respect to the main scanning are changed to prevent gaps or overlaps from occurring between the beam spots and form a desired halftone dot pattern. That's what I do. Specifically, the number of laser beam irradiation systems to be driven in each laser beam irradiation section is input from the panel 33, and the beam diameter and main scanning direction are determined from the input values based on a calculation formula stored in memory in advance. The beam diameter J5 is automatically calculated according to this calculated value.
By changing the speed of the sub-scanning with respect to the main scanning, an appropriate halftone dot pattern is formed according to the number of laser beam irradiation systems to be driven.

As described above, according to the apparatus of this embodiment, when changing the number of fine lines, it is possible to obtain a halftone dot pattern according to the application by changing the nature of the laser beam irradiation system to be driven in the laser beam irradiation section. This greatly improves work efficiency.

This apparatus is extremely useful not only in the case described above, but also in changing the number of laser beam irradiation systems to be driven, for example, when recording continuous tone images.

In the embodiment described above, the number of laser beam irradiation parts (+++) is 4, and the number of laser beam irradiation systems for each laser beam irradiation and sword part is 4 stages. It goes without saying that even if there is an increase or decrease, the setting value of the h1 formula stored in the memory can be changed to use the same method as in the above-mentioned embodiment.

[Brief explanation of drawings]

1 and 2 are schematic diagrams showing the irradiation system and the position of the beam spot, which are used to explain the present invention in detail. FIG. 3 shows an embodiment of the optical rotary puller according to the present invention. 4 is an enlarged side view of a part of the device shown in FIG. 3; FIG. 5 is a schematic diagram schematically showing a part of the device shown in FIG. 3; FIG. 1 is an enlarged cross-sectional view of a part of the device in FIG. 3; FIG. 7 is a perspective view of the device in FIG. 3; FIG. 8 and 9 are a perspective view of the device in FIG. 3; FIG. 2 is a schematic diagram showing an example of a halftone dot pattern drawn when a halftone plate is made by the apparatus. 1... Frame 2... Platen 3... Arm 4... Rotating disk 1G...
Note Q Ia 20... Ray IJ'' beam irradiation section 21.
...Laser beam irradiation system Fig. 1 w12 Fig. 3 Fig. @6 Fig. 9a 8 Fig. 9

Claims (1)

[Scope of Claims] Provided radially outward at positions equidistant from the rotation axis of the mouth at intervals of a constant angle θ° centered on the rotation axis and offset by an amount of μnL in the direction of the rotation axis. (360) A light beam irradiation unit consisting of a plurality of light sources driven by a modulated signal with a variable beam diameter. a group of 11 light beam irradiation systems arranged at intervals of a recording material supporting means for supporting a recording material formed in a cylindrical shape around the rotation axis so as to be close to and facing the group; one of the light beam irradiation system group and the recording material supporting means; main scanning drive means for rotating the light beam at high speed around the rotation axis, and one of the light beam irradiation system group and the recording material support means in the direction of the rotation axis and on the recording material from the light source. In an optical rotary printer consisting of a sub-scanning drive means for moving the irradiation positions of the light beams in directions away from each other, each of the light sources of each of the irradiation parts has a corresponding continuous n.
The light beam diameter of each light source on the recording material is set to 601-360-mn0 μm, and the sub-scan is set to Amn360 with respect to the main scan of 1°.
- An optical rotary printer characterized in that mnθ μnL.