GB2130836A

GB2130836A - Optical rotational printer

Info

Publication number: GB2130836A
Application number: GB08324736A
Authority: GB
Inventors: Etsuo Shiozawa; Masahiro Oonishi; Shigeo Harada
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 1982-09-16
Filing date: 1983-09-15
Publication date: 1984-06-06
Also published as: DE3333368A1; GB2130836B; JPS5949986A; GB8324736D0

Abstract

A printer comprises a rotating member (4) carrying groups (20) of recording light emitting systems (21) having light sources (23) and condenser lenses, on its peripheral surface (13), a power feeder for feeding a modulated signal to the light sources, and an arcuately curved platen (2) for supporting a recording material (16). The groups of the light emitting systems are symmetrically positioned around the periphery of the member (4), with their centers aligned with one another on a common circumference (C). The light sources (23) of each emitting system group are mounted tiltably so that light beams impinging on the recording material are staggeredly shifted at equal intervals in a direction parallel to the rotation axis of the rotatable member. During printing the rotatable member is moved along and rotated about the rotation axis. The light emitting systems of each group scan adjacent lines, with the axial movement of the member being such that the first light emitting system of the next to scan group, scans the next adjacent line. <IMAGE>

Description

SPECIFICATION Optical rotational printer This invention relates to a printer for recording information on a recording material by use of light such as a laser beam modulated with a signal carrying the information. This invention particularly relates to an optical rotational printer for recording the information on a stationary recording material by use of recording light emitted from light sources mounted on a rotatable member and rotated thereby.

Since laser sources can generate a light beam exhibiting high spatial interference and high spectral line luminance which cannot be obtained with other types of light sources, laser sources are used in various optical recording and read-out apparatuses. As an optical recording apparatus for recording information by use of a laser beam, there has heretofore been known an apparatus wherein a laser beam modulated with a signal carrying the information is deflected by a light deflector such as a galvanometer mirror or a multi-face rotating mirror, and a recording material sensitive to the laser beam is tw'odimensionally scanned with the laser beam to record the information thereon. However, since the apparatus of this type uses expensive devices such as the rotating mirror and an f0 lens, the cost of manufacture is high.Further, since the optical path between a condenser lens of the laser beam emitting system and the recording material is long, it is impossible to condense the laser beam at a high density and to accomplish recording at a high resolution and a high luminance. In order to shorten the distance between the condenser lens and the recording material, there has been proposed a laser printer wherein a recording material is supported on the peripheral surface of a rotatable drum-like platen, and a laser beam emitting system is positioned near the peripheral surface of the platen, whereby main scanning is conducted by the rotation of the platen and subscanning is conducted by moving the laser beam emitting system along the rotational axis of the platen.In this apparatus, however, the size of the drum-like platen for supporting a recording material having a practical level of size becomes very large, and it becomes impossible to rotate the platen-it high speeds. Therefore, the laser printer having such a construction cannot conduct recording at high speeds.

It is an object of the present invention to provide a printer capable of recording information rapidly at a high resolution and at a high luminance.

According to the invention there is provided an optical rotational printer comprising a rotatable member rotatably supported on a stationary base and provided in the peripheral surface thereof with a plurality of recording light emitting systems each comprising light sources and condenser lenses for emitting recording light outwardly, a rotating means for rotating said rotatable member, an electric power feeding means for feeding an electric power modulated with a predetermined modulation signal to said light sources in said rotatable member, and a platen for holding a recording material in concentric facing relation to said rotatable member, said recording light emitting systems being grouped into a plurality of light emitting sections in the peripheral surface of said rotatable member which are in equally spaced relation to one another, the centers of the systems of each section being aligned with one another and the centers of the sections being positioned on a common circumferential line, and the positions of said recording light emitting systems being such that in use the light beams from each section impinging on said recording material are shifted in equally spaced relation to one another in the direction of the rotational axis of said rotatable member.

The printer of the present invention is particularly characterized by the positioning of finely adjustable recording light emitting systems comprising light sources and condenser lenses for emitting recording light outwardly in the peripheral surface of a rotatable member in concentric facing relation to which a recording material may be supported. The rotatable member is suitably movable relative to the platen in a direction parallel with its rotational axis to enable two-dimensional scanning of recording material on the platen with recording light emitted from said recording light emitting systems by the movement of the rotatable member along the rotation axis thereof with respect to said recording material. For this purpose the rotatable member is conveniently provided with moving means for moving it in a direction parallel with its rotational axis.Similarly, the platen is conveniently held static and may suitably be positioned integrally in the stationary printer base.

In a preferred embodiment of the invention the light sources in the recording light emitting systems are mounted to be rotatably adjustable with respect to the optical axes of the respective systems. In accordance with this respect of the present invention, in an optical system of a multilight beam printer capable of forming scanning lines parallel to one another by positioning a plurality of light beams which become elliptic on a scanning surface, the elliptic light beams on the scanning surface are made rotatable. Further, in this aspect of the present invention, since the scanning surface is scanned with a plurality of light beams by the movement of the light beams with respect to the scanning surface, the scanning mechanism can be optically and mechanically embodied in various ways.To achieve the rotation of the elliptic light beams, the light sources may be rotated or the rotation may be conducted by an optical means. Though many light sources should preferably be used, it is also possible to form many light beams by use of a single light source.

The light sources are activated to represent the information by a drive current modulated with a modulation signal carrying the information, as in the case of other printers of this type.

in the optical rotational printer of the present invention wherein the recording material is maintained stationary and the light sources are rotated, the recording light emitting systems comprising semi-conductor laser sources or the like can be made very small and, therefore, the rotatable member for mounting the recording light emitting systems can be made small in size and light in weight. Accordingly, it is possible to rotate the rotatable member at high speeds and conduct recording at high speeds. Since the recording light emitting systems can be positioned near the recording material, it is possible to sufficiently condense the laser beams and conduct recording at a high resolution and a high luminance.Further, since the recording light emitting systems are rotatable and the crosssectional shapes of the light beams can be rotated on the recording material, it is possible to eliminate recording nonuniformity.

Further, in the present invention, since the light intensity distribution formed by the adjacent light beams can be changed in the direction perpendicular to the scanning direction, it is possible to conduct high-quality recording (for example, exhibiting-no nonuniformity) or specialeffect recording (including blurring) by changirig the angles of the elliptic light beams and thereby overlapping the light beams or separating them from one another or changing the extent of overlapping according to the property of the recording material and/or gradation.In addition to the semiconductor lasers as mentioned above, light emitting diodes which are light in weight and can be directly modulated at high speeds and which emit a light beam exhibiting a high luminance and characteristics such as convergence similar to the characteristics of laser beams can also be used as the light sources.

An embodiment of the invention will now be described by way of Example and with reference to the accompanying drawings in which: Figure 1 is a partially cutaway perspective view showing an embodiment of the optical rotational printer in accordance with the present invention; Figure 2 is an enlarged side view showing a part of the printer of Figure 1; Figure 3 is a schematic view showing a part of the printer of Figure 1; Figure 4 is a sectional view showing a part of the printer of Figure 1; and Figure 5 is an enlarged perspective view showing a part of the printer of Figure 1.

Referring to Figure 1, the optical rotational printer has a platen 2 having a curved upper surface and secured to a frame 1 ona desk, and a rotatable disk 4 supported above the platen 2 by an arm 3. The arm 3 has rod bearings 5 and 6 at the back portion, and rods 7 and 8 parallel with each other and secured to the frame 1 are inserted respectively in the rod bearings 5 and 6.

Therefore, the arm 3 is supported by the rods 7 and 8 and can be slid in the direction of the arrow A. A nut 9 is secured to the arm 3 between the rod bearings 5 and 6 and screw-engaged with a screw rod 11 rotated by an arm moving motor 10.

Therefore, when the arm moving motor 10 is driven and the screw rod 11 is rotated, the arm is moved in the direction of the arrow A.

Figure 2 is an enlarged view showing the platen 2 and the rotatable disk 4 supported on the arm 3. As shown in Figure 2, the platen 2 has an upper curved face 12 for supporting a recording paper, which is formed concentrically with the peripheral surface 13 of the rotatable disk 4. At certain positions of the recording paper supporting face 1 2 are provided recording paper suction holes 1 4 connected to the suction side of a vacuum pump 15 built in the apparatus via pipes (not shown).Therefore, when a recording paper 1 6 for recording information upon exposure to, for example, a laser beam is placed in a predetermined position on the recording paper supporting face 1 2 of the platen 2 and the vacuum pump 1 5 is operated, the recording paper 1 6 is firmly secured to the recording paper supporting face 1 2. However, the method of retaining the recording paper 1 6 is not limited to securing by suction, and any other known method may be used. Further, instead of using the recording paper 16, any other recording material may be used.

The rotatable disk 4 is formed by mounting a cover plate 18 (as shown in Figure 1) on a shallow-bottomed cylindrical member consisting of the peripheral surface 1 3 and a bottom surface 1 7. The peripheral surface 1 3 is provided with four oblong laser beam emitting windows 1 9 positioned at equal intervals on the same circumference.Inside each laser beam emitting window 1 9 is positioned a laser beam emitting section 20 for emitting laser beams outwardly through the laser beam emitting window 1 9. The laser beam emitting sections 20 are secured to the bottom surface 1 7. As schematically shown in Figure 3, in each laser beam emitting section 20, four laser beam emitting systems 21 are secured with their centers aligned in the circumferential direction of the rotatable disk 4. The four laser beam emitting sections 20 are identical with one another and, therefore, the centers of the laser beam emitters of the four laser beam emitting sections 20 are all positioned on the same circumferential line. Namely, the sixteen laser beam emitting systems 21 are positioned on a single common circumferential line. Each laser beam emitting system 21 comprises a semiconductor laser 23 and a condenser lens 24 supported in a cylindrical support 22.

As shown in Figure 4, each semiconductor laser 23 is supported in its support 22 by fine adjustment screws 25. By operating the fine adjustment screws 25, it is possible to swing the optical axes of the laser beams independently of one another in the direction of the arrow B shown in Figure 3. Further, the laser beam emitting systems 21 can be tilted around the optical axes thereof.

Further, as shown in Figure 5, in each laser beam emitting section 20, the optical axes of the four laser beam emitting systems 21 are adjusted so that the optical axis Lb of the second laser beam emitting system 21 b is aligned with the mounting center C of the emitting systems, the optical axis La of the first laser beam emitting system 21 a is shifted 12ym on the recording paper 1 6 in the rightward direction of the arrow A shown in Figure 1 from the mounting center C of the emitting systems, the optical axis Lc of a third laser beam emitting system 21 c is shifted 12ym on the recording paper 1 6 in the leftward direction of the arrow A from the mounting center C, and the optical axis Ld of a fourth laser beam emitting system 21 d is shifted 24ym on the recording paper 1 6 in the leftward direction of the arrow A from the mounting center C. Therefore, the four laser beams emitted from each laser beam emitting section 20 are directed to the recording paper 1 6 at 12ym intervals in the moving direction of the rotatable disk 4 (i.e. in the direction of the arrow A in Figure 1).

These four laser beams are directed to the recording paper 1 6 with their centers being spaced by a predetermined distance (12um in the embodiment shown) from one another. In general, the cross-sectional shapes of the laser beams on the recording paper 1 6 are elliptic. In this case, the longer diameters of the ellipses of the laser beams may be positioned in the main scanning direction or in the sub-scanning direction. The laser beams should preferably be adjusted so that the scanning lines formed by the adjacent laser beams partially overlap one another when scanning on the recording paper 1 6. When the scanning lines of the laser beams are not overlapped, it sometimes happens that gaps occur in recording between the scanning lines.

Further, as it is not always possible to obtain semiconductor lasers exhibiting the same light diverging angle, the scanning lines formed by the laser beams should for this reason too preferably be partially overlapped. Further, when the directions of the longer diameters of the laser beams are made rotatable as desired, even if there is a fluctuation in characteristics among many semiconductor lasers, it becomes possible to eliminate recording nonuniformity by mounting some semiconductor lasers at angles different from the angles of the other semiconductor lasers (by changing the directions of the longer diameters of the elliptic beams).

The rotatable disk 4 provided with the laser beam emitting sections 20 as described above is rotated in the direction of the arrow D shown in Figure 1 by a motor 26 for an outer rotor secured to the central portion of the rotatable disk 4. A secondary print coil 27 is secured inside the cover plate 18 of the rotatable disk 4, and a primary print coil 29 is secured inside a bearing portion 28 of the arm 3. To the primary print coil 29 on the stationary side is fed a high-frequency current for driving the semiconductor lasers, which is modulated with a signal carrying the information to be recorded, via a cable 31 hung from a wire 30 as shown in Figure 1.The high-frequency current fed to the primary print coil 29 is transmitted to the secondary print coil 27 in the rotatable disk 4 in a non-contact manner by inductive coupling between the stational primary print coil 29 and the rotatable secondary print coil 27. Feeding of the semiconductor laser drive current to the rotatable disk 4 may instead be conducted by using a slip ring and a brush.

However, current feeding by inductive coupling is advantageous since no noise occurs and there is no risk of the ambient electric circuits being adversely affected by noise. Current feeding to the motor 26 for rotating the rotatable disk 4 is also conducted by using the cable 31. Detection of the starting point of the rotatable disk 4 is conducted by use of a rotary encoder (not shown) secured within the rotatable disk 4 and a detecting section (not shown) secured to the arm 3. The section wherein the rotatable disk 4 is moved is covered by a cover 32 as partially shown in Figure 1.

When the cover 32 is made of a material permeable to visible light to which the recording paper 1 6 is not sensitive, it becomes possible to monitor the operation of the apparatus from outside.

The operation of the above-described embodiment of the optical rotational printer will now be described below. The printer is connected to a recording information sending apparatus via cords, and the operation of the printer is controlled from a control panel 33 on the front side of the printer. Before the recording is started, the rotatable disk 4 is positioned at the right end portion of the recording paper 1 6. When a signal representing the information to be recorded is sent from the recording information sending apparatus and the printer is turned on, the rotatable disk 4 is rotated in the direction of the arrow D shown in Figure 1 by the motor 26. At the same time,*the arm 3 supporting the rotatable disk 4 is moved in the leftward direction of the arrow A shown in Figure 1.Therefore, the rotatable disk 4 is rotated and simultaneously moved above the recording paper 1 6 in the leftward direction in Figure 1. As a result, the recording paper 1 6 is two-dimensionally scanned with the laser beams emitted through the laser beam emitting windows 19 of the rotatable disk 4 in the rotating direction of the rotatable disk 4 as the main scanning direction and in the moving direction of the rotatable disk 4 parallel with the rotation axis thereof as the sub-scanning direction. As described above, the optical axes of the four laser beam emitting systems 21 of each laser beam emitting section 20 of the rotatable disk 4 are adjusted so as to be shifted on the recording paper 16 by 12ym from one another in the moving direction of the rotatable disk 4.

Therefore, when each laser beam emitting section 20 once passes over the recording paper 16, the recording paper 1 6 is scanned with four scanning lines each having a scanning width of 12cm. As shown in Figure 2, the four laser beam emitting sections 20 are positioned so that, when one laser beam emitting section 20 rotates 90 on a recording surface E of the -recording paper 1 6 and finishes scanning, the next laser beam emitting section 20 simultaneously comes to the end portion of the recording surface E and starts scanning.Further, the arm 3 is constructed so that it is moved by 48,um (i.e. 1 2,um x4) when the rotatable disk 4 is rotated 90 . Accordingly, the scanning width of each scanning line is always maintained at 12cm. Since the semiconductor lasers 23 of the laser beam emitting systems 21 emitting the laser beams for scanning on the recording paper 1 6 are driven by a drive current modulated with a modulation signal carrying the recording information, which is fed from the recording information sending apparatus, the information sent from the recording information sending apparatus is recorded on the recording paper 16 sensitive to the laser beams emitted from the laser beam emitting systems 21.After the recording of the information is finished, the arm 3 is returned to the stand-by position at the right of Figure 1 and readied for the next recording operation.

In the embodiment described above, since semiconductor lasers which have a simple construction and which are small in size and light in weight are mounted in the thin rotatable drum and two-dimensional scanning with the laser beams is conducted by rotating and moving the rotatable drum; it becomes possible to rotate the rotatable drum at high speeds and obtain high recording speeds. Further, since the laser beam emitting systems 21 of the laser beam emitting sections 20 are positioned in a straight line in the rotating direction of the rotatable disk and the optical axes of the semiconductor lasers can be shifted by using the fine adjustment screws, it is possible to obtain a very small scanning width (124m) and conduct the information recording at a high density.

The method of positioning the recording light emitting systems in the rotatable member is not limited to the method used in the abovedescribed embodiment. When more emitting sections are positioned in the peripheral surface of the rotatable member so that one of these emitting sections always emits the recording light to the recording material when the rotatable member is rotated, it is possible to utilize the rotation of the rotatable member to the maximum extent. Further, when more recording light emitting systems are positioned in each emitting section, it becomes possible to conduct scanning of more scanning lines at a time. These configurations are advantageous to further increase the recording speed.

It will thus be seen that the present invention provides a printer capable of recording information rapidly, uniformly and at high resolution.

Claims

1 An optical rotational printer comprising a rotatable member rotatably supported on a stationary base and provided in the peripheral surface thereof with a plurality of recording light emitting systems each comprising light sources and condenser lens for emitting recording light outwardly, a rotating means for rotating said rotatable member, an electric power feeding means for feeding an electric power modulated with a predetermined modulation signal to said light sources in said rotatable member, and a platen for holding a recording material in concentric facing relation to said rotatable member said recording light emitting systems being grouped into a plurality of light emitting sections in the peripheral surface of said rotatable member which are in equally spaced relation to one another, the centers of the systems of each section being aligned with one another and the centers of the sections being positioned on a common circumferential line, and the positions of said recording light emitting systems being such that in use the light beams from each section impinging on said recording material are shifted in equally spaced relation to one another in the direction of the rotational axis of said rotatable member.

2. A printer as claimed in ciaim 1 further comprising a moving means for moving said rotatable member in the direction parallel with the rotation axis of said rotatable member.

3. A printer as claimed in either of claims 1 and 2 wherein said light sources are semiconductor lasers.

4. A printer as claimed in any one of claims 1 to 3 wherein said electric power feeding means comprises an inductive coupling means for transmitting the electric power in the noncontacting condition.

5. A printer as claimed in any one of claims 1 to 4 wherein said light sources are mounted to be rotatably adjustable with respect to the optical axes of their respective recording light emitting systems.

6. An optical rotational printer substantially as hereinbefore described comprising a rotatable recording light source carrying member and a platen mounted in concentric facing relation thereto.

7. An optical rotational printer substantially as hereinbefore described with reference to the accompanying drawings.