GB2151108A - Beam deflecting method and device for use in image reproduction - Google Patents

Beam deflecting method and device for use in image reproduction Download PDF

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Publication number
GB2151108A
GB2151108A GB08430240A GB8430240A GB2151108A GB 2151108 A GB2151108 A GB 2151108A GB 08430240 A GB08430240 A GB 08430240A GB 8430240 A GB8430240 A GB 8430240A GB 2151108 A GB2151108 A GB 2151108A
Authority
GB
United Kingdom
Prior art keywords
mirror
beams
electromagnetic radiation
oscillatable
oscillation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB08430240A
Other versions
GB8430240D0 (en
Inventor
Kiyoshi Maeda
Tsutomu Ueyama
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dainippon Screen Manufacturing Co Ltd
Original Assignee
Dainippon Screen Manufacturing Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dainippon Screen Manufacturing Co Ltd filed Critical Dainippon Screen Manufacturing Co Ltd
Publication of GB8430240D0 publication Critical patent/GB8430240D0/en
Publication of GB2151108A publication Critical patent/GB2151108A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/113—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using oscillating or rotating mirrors
    • H04N1/1135—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using oscillating or rotating mirrors for the main-scan only
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/047—Detection, control or error compensation of scanning velocity or position
    • H04N1/053—Detection, control or error compensation of scanning velocity or position in main scanning direction, e.g. synchronisation of line start or picture elements in a line
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/207—Simultaneous scanning of the original picture and the reproduced picture with a common scanning device
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/12—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using the sheet-feed movement or the medium-advance or the drum-rotation movement as the slow scanning component, e.g. arrangements for the main-scanning
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/04—Scanning arrangements
    • H04N2201/047—Detection, control or error compensation of scanning velocity or position
    • H04N2201/04701—Detection of scanning velocity or position
    • H04N2201/0471—Detection of scanning velocity or position using dedicated detectors
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/04—Scanning arrangements
    • H04N2201/047—Detection, control or error compensation of scanning velocity or position
    • H04N2201/04701—Detection of scanning velocity or position
    • H04N2201/04734—Detecting at frequent intervals, e.g. once per line for sub-scan control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/04—Scanning arrangements
    • H04N2201/047—Detection, control or error compensation of scanning velocity or position
    • H04N2201/04701—Detection of scanning velocity or position
    • H04N2201/04744—Detection of scanning velocity or position by detecting the scanned beam or a reference beam
    • H04N2201/04746—Detection of scanning velocity or position by detecting the scanned beam or a reference beam after modulation by a grating, mask or the like

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Facsimile Scanning Arrangements (AREA)
  • Fax Reproducing Arrangements (AREA)
  • Mechanical Optical Scanning Systems (AREA)
  • Laser Beam Printer (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)

Abstract

A beam deflecting method and device for image recording apparatus are described. The device comprises one or more light sources (5) providing respective light beams (R,S,G). The light beams (R,S,G) are deflected by respective reflection mirrors (6', 6'', 6'') onto an oscillating mirror (16) so as to be incident at one point on the oscillation axis thereof but at different angles thereto. The oscillation mirror (16) is oscillated to scan the light beams (R,S,G) via further optical means (12,13) across a photosensitive substrate (18), an original image (2') and a scanning position determining grating (14). The use of a common point on the axis allows the oscillating mirror to be small and of low inertia. <IMAGE>

Description

SPECIFICATION Beam deflecting method and device for use in image reproduction THIS INVENTION relates to a beam deflecting method and device for use in the reproduction of images by scanning an original image to be reproduced and recording a reproduction image on a photosensitive material by deflecting optical scanning and recording beams relative to the original and the photosensitive material, respectively, at high speed by means of an oscillatable mirror.
In a known image reproducing apparatus in which optical beams are deflected in a main scanning direction so asto scan the original image as it is moved in a subsidiary direction and the reproduction image is simultaneously reproduced on a photosensitive material,the deflection ofthe beams is performed by means of a rotatable polygonal mirror or an oscillatable mirror.
In the case of a device and method using a polygonal mirror, rather high speed scanning is possible, but a problem exists in securing deflection accuracy because the machining accuracy ofthe polygonal mirror itself and ofthe rotary shaft to which the mirror is attached can hardly be improved.
In the case of a device and method using an oscillatable scanning mirror, the moment of inertia of the mirror is large and the mirror oscillation control speed is low if the centre of oscillation is not positioned at the centre ofthe mirror. If the centre of oscillation is positioned at the central axis of the mirror,the size ofthe mirror becomes largerto accommodate the incidence of two or more beams to be deflected at respective, different points on the axis of oscillation. The moment of inertia ofthe mirror also becomes larger in any ofthe above said cases and sufficient responsiveness can not be obtained. It is also difficult to improve the machining accuracy because of the large surface area of the mirror.
With low deflection accuracy and low responsiveness, the expected resolution can not be obtained and the recording speed can not be increased either.
An objectofthis invention isto enable the recording speed of image reproducing apparatusto beim- proved, and another object ofthis invention is to make the deflection mirror smaller so as to lowerthe moment of inertia of the mirror and thereby increase the oscillation speed.
Accordingly, in one aspect, there is provided a beam deflectingdeviceforan image reproducing apparatus, which device comprises an oscillatable mirror which is oscillatable about an axis of oscillation to cause beams of electromagnetic radiation incident thereon to be deflected for scanning an original image and a photosensitive substrate and for determining a scanning position, and optical means for causing the beams of electromagnetic radiation to be incident at one point on the axis of oscillation of the oscillatable mirror.
The invention also provides a beam deflecting method for image reproducing apparatus, which method comprises causing a plurality of beams of electromagnetic radiation to be incident at one point on the axis of oscillation of an oscillatable mirror using optical means, and oscillating the oscillatable mirror about the axis of oscillation in a main scanning direction to causethe electromagnetic beams incident thereon to be deflected for scanning an original image and a photosensitive substrate and for determining a scanning position.
Preferably, further optical means are provided for deflecting the beams of electromagnetic radiation reflected from the oscillatable mirror to cause respective electromagnetic beams to scan an original image and a photosensitive substrate and to determine a scanning position.
The optical means may comprise means for arranging the beams of electromagnetic radiation incident on the oscillatable mirror to be at an angle relative to one another such that each electromagnetic radiation beam is at a different angle to the axis of oscillation of the oscillatable mirror and the arranging means may comprise respective reflecting mirrors each arranged at a different angle to the axis of oscillation ofthe oscillatable mirror.
Conveniently, at least one light source, possibly a laser, and meansforforming a plurality of optical beams therefrom are provided.
Embodiments of the present invention may provide the following advantages: (i) The size of the oscillatable mirror can be smaller than in the case where the beams are incident on the mirror at different points on the axis of oscillation of the mirror. As a result, the deflection accuracy can be much improved becausethemachining accuracy of the mirror itself, which is required to have high accuracy in a device ofthis kind, can be increased.
Moreover, oscillation control is easier, responsiveness is improved, deflection can be faster, and the recording speed can also be increased since the momement of inertia of the mirror itself can be smaller.
(ii) The deflection width at the focal plane of the optical beams is determined by the deflection angle of the oscillating mirror and the characteristics of the objective lens. Accordingly, the responsiveness of the oscillatable mirror is much improved and the oscillation control becomes easier, resulting in easier and more accurate synchronous control of scanning and exposure and, consequently, higher resolution ofthe reproduction image.
In order that the invention may be readily understood, an embodimentthereofwill now be described, by way of example, with reference to the accompanying drawings, in which.
FIGURE 1, is a perspective view, showing the overall configuration of image reproducing apparatus embodying the present invention, and FIGURE 2 is a schematic view, showing the structure ofthe optical path in the image reproducing apparatus ofFigure 1.
Referring now to the drawings, the general configuration of an image reproducing apparatus 1 embodying this invention is shown in Figure 1, while Figure 2 is a schematic drawing of optical means ofthe image reproducing apparatus 1. In the apparatus 1, an original 2' placed on an originals board 2 istransferred by a motor 3 in a subsidiary scanning direction to a scanning unit 15 including a reflection mirror and receiving sensors (neither shown). A photosensitive sheet material or substrate 18 mounted on a recording drum 4 is movable in the subsidiary scanning diirection in sequential order.
A scanning beam S, a recording beam Rand a scanning position detecting beam G are respectively derived from lightsources 5', 5" and 5". Each one of these beams goes through a group of relay lenses (not illustrated), an acousto-optic modulator 8, a beam expander 9, a respective reflecting mirror 6, an oscillatable mirror 16 of a galvanometer 20 and an objective lens 11 to scan a respective one of the original 2', the photosensitive material 18 and a grating 14. Thus, a mirror 12 reflects the scanning position detection beam G emerging from the objective lens 11 onto the grating 14, and a mirror 13 reflects onto the original 2' the scanning beams S projected from the objective lens 11. The recording beam R emerging from the objective lens 11 passes directly to the photosensitive substrate.The length ofthe optical path from the objective lens 11 to each of the original 2', the grating 14 and the photosensitive materials is equal to the focal length ofthe objective lens 11.
The oscillatable mirror 16 is driven buy a drive unit 17 using a drive signal which takes the deflection width determined by a focal length ofthe objective lens 11 and the deflection angle of the mirror 16 into consideration. Accordingly, each one ofthe beams R, Sand G reflected by the oscillatable mirror 16 is deflected into the main scanning direction.
As illustrated in the drawings, ofthe incident beams R, Sand G projected onto the centre of the oscillating mirror 16,the beams and G are set at a certain angle relative to the recording beam R so as to prevent mututal interference between the optical beams.
Thus, each ofthe beams, S, G and R is at a different angle to the axis of oscillation ofthe mirror 16. In other words, the optical path ofthe recording beam Rfrom the light sourceS' an (Argon (Ar) laser, for example), to the mirror 16 via the mirror 6' extends parallel to a base 7, while the optical paths ofthe scanning beam S and the scanning detecting beam G from the respective light sources 5" and 5"' (Helum-Neon (He-Ne) lasers, for example) to the respective reflection mirrors 6", and 6"' extend parallel to to the optical path ofthe recording beam R but at different heights.The reflection mirrors 6" and 6"' are tilted slightly upwardly and downwardly, respectively, so that each ofthe beams Sand G is incident on the mirror 16 from the reflecting mirrors 6"and 6"' ata slight angle (3 , for example) to the recording beam R. In this way, the centre lines of the beams R, S, and G converge at a common point on the mirror 16 without mutual optical interference. The reflection surface ofthe mirror 16 can consequently be madeverysmall.
Thus, using a beam deflecting device and beam deflecting method in accordance with this invention, the incident optical axis of each beam is converged onto only one point on the oscillation axis of the oscillatable mirror when carrying out scanning and recording in the direction of main scanning on an original image and a photosensitive material or substrate by a plurality of laser beams such as scanning and recording beams projected from the lightsource, expanding the beams to be parallel convergent beams of a required diameter, directing the beams onto the oscillatable mirror and deflecting each beam.

Claims (1)

1. A beam deflecting device for an image reproducing apparatus, which device comprises an oscillatable mirror which is oscillatable about an axis of oscillation to cause beams of electromagnetic radition incident thereon to be deflected for scanning an original image and a photosensitive substrate and for determining a scanning position, and optical means for causing the beams of electromagnetic radiation to be incident at one point on the axis of oscillation of the oscillatable mirror.
2. A device according to Claim 1, wherein further optical means are provided for deflecting the beams of electromagnetic radiation reflected from the oscillatable mirrorto cause respective beams to scan an original image, to scan a photosensitive substrate and to determine a scanning position.
3. A device according to Claim 1 or 2, wherein the optical means comprises means for arranging the beams of electromagnetic radiation to be incident on the oscillatable mirror at an angle relative to one another such that each electromagnetic radiation beam is at a different angle to the axis of oscillation axis ofthe oscillatable mirror.
4. A device according to Claim 3, wherein the arranging means comprises respective reflecting mirrors each arranged at a different angleto the axis of oscillation ofthe oscillatable mirror.
5. A device according to claim 1,2,3 or4, further comprising at least one electromagnetic radiation source and meansforforming the plurality of beams of electromagnetic radiation therefrom.
6. A device according to Claim 5, wherein the or each light source is a laser.
7. Abeam deflecting device for image reproducing apparatus substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.
8. A beam deflecting method for image reproducing apparatus, which method comprises causing a plurality of beams of electromagnetic radiation to be incident at one point on the axis of oscillation of an oscillatable mirror using optical means and oscillating the oscillatable mirror about the axis of oscillation in a main scanning direction to cause the beams electromagnetic radiation incidentthereon to be deflected for scanning an original image and a photosensitive substrate and for determining a scanning position.
9. A method according to Claim 8, wherein the beams of electromagnetic radiation reflected from the oscillatabie mirror are deflected using further optical means to cause respective beams to scan an original image, to scan a photosensitive substrate and to determine a scanning position.
10. According to claim 8 or9, wherein the beams of electromagnetic radiation are arranged by the optical means to be incident on the oscillatable mirror at different angles to the axis of oscillation.
11. A method according to Claim 10, wherein each beam of electromagnetic radiation is reflected onto the oscillatable mirror by means of a reflecting mirror arranged at an angle to the oscillation axis of the oscillatable mirror.
12. Abeam deflecting methodforimagereproduc- ing apparatus substantially as hereinbefore described with reference to the accompanying drawings.
f3 [mage reproduction apparatus whenever incorporating a beam deflection device in accordance with any one of claims 1 to7 andlorwheneverusing a beam deflecting method in accordance with any one ofclaims8to 12.
14. Any novel feature or combination offeatures described herein.
GB08430240A 1983-12-06 1984-11-30 Beam deflecting method and device for use in image reproduction Withdrawn GB2151108A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP58231108A JPS60122918A (en) 1983-12-06 1983-12-06 Beam deflecting device and beam deflecting method of picture scanning and recording device

Publications (2)

Publication Number Publication Date
GB8430240D0 GB8430240D0 (en) 1985-01-09
GB2151108A true GB2151108A (en) 1985-07-10

Family

ID=16918422

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08430240A Withdrawn GB2151108A (en) 1983-12-06 1984-11-30 Beam deflecting method and device for use in image reproduction

Country Status (3)

Country Link
JP (1) JPS60122918A (en)
DE (1) DE3441772A1 (en)
GB (1) GB2151108A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0250132A2 (en) * 1986-06-07 1987-12-23 Konica Corporation Image recording apparatus
GB2293872A (en) * 1994-10-08 1996-04-10 Ian Reid Lewis Apparatus for emitting a beam of radiation

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1254664A (en) * 1969-05-08 1971-11-24 Singer General Prec Inc Scanning system for a beam

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4015081A (en) * 1975-02-03 1977-03-29 Xerox Corporation Multifunction scanning system
US4231070A (en) * 1978-12-07 1980-10-28 Texaco Inc. High speed copying means and method

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1254664A (en) * 1969-05-08 1971-11-24 Singer General Prec Inc Scanning system for a beam

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0250132A2 (en) * 1986-06-07 1987-12-23 Konica Corporation Image recording apparatus
EP0250132A3 (en) * 1986-06-07 1989-08-02 Konishiroku Photo Industry Co. Ltd. Image recording apparatus
GB2293872A (en) * 1994-10-08 1996-04-10 Ian Reid Lewis Apparatus for emitting a beam of radiation

Also Published As

Publication number Publication date
DE3441772A1 (en) 1985-08-14
JPS60122918A (en) 1985-07-01
GB8430240D0 (en) 1985-01-09

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)