EP0059514A2 - Procédé et appareil pour la présentation électrophotographique d'information - Google Patents

Procédé et appareil pour la présentation électrophotographique d'information Download PDF

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Publication number
EP0059514A2
EP0059514A2 EP82200244A EP82200244A EP0059514A2 EP 0059514 A2 EP0059514 A2 EP 0059514A2 EP 82200244 A EP82200244 A EP 82200244A EP 82200244 A EP82200244 A EP 82200244A EP 0059514 A2 EP0059514 A2 EP 0059514A2
Authority
EP
European Patent Office
Prior art keywords
cathode ray
ray tube
recording medium
line
screen
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.)
Granted
Application number
EP82200244A
Other languages
German (de)
English (en)
Other versions
EP0059514B1 (fr
EP0059514A3 (en
Inventor
Ulrich Dr. Schiebel
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.)
Philips Intellectual Property and Standards GmbH
Koninklijke Philips NV
Original Assignee
Philips Patentverwaltung GmbH
Philips Gloeilampenfabrieken NV
Koninklijke Philips Electronics NV
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 Philips Patentverwaltung GmbH, Philips Gloeilampenfabrieken NV, Koninklijke Philips Electronics NV filed Critical Philips Patentverwaltung GmbH
Publication of EP0059514A2 publication Critical patent/EP0059514A2/fr
Publication of EP0059514A3 publication Critical patent/EP0059514A3/de
Application granted granted Critical
Publication of EP0059514B1 publication Critical patent/EP0059514B1/fr
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/10—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes
    • H01J31/12—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes with luminescent screen
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/32—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the charge pattern is formed dotwise, e.g. by a thermal head
    • G03G15/326—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the charge pattern is formed dotwise, e.g. by a thermal head by application of light, e.g. using a LED array
    • G03G15/328—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the charge pattern is formed dotwise, e.g. by a thermal head by application of light, e.g. using a LED array using a CRT

Definitions

  • the invention relates to a method and an arrangement for the electrophotographic representation of an electrically stored information with a cathode ray tube, the luminous layer of which is covered line by line by a cathode ray in accordance with the stored information, and with a photoconductive recording medium, on the photoconductive layer of which is activated by the activated luminous layer of the cathode ray tube
  • Optical system a mosaic-like latent charge image is created, which is then transferred to another record carrier, the minimum line frequency with which the cathode beam is deflected corresponds to the quotient of the feed speed of the record carrier and the line spacing.
  • an electrophotographic device in which the illuminated dots of a character to be displayed on the screen of a cathode ray tube are optically transmitted to a recording medium via an optical system consisting of mirrors and lenses.
  • the entire character of the character is recorded on the screen in a grid pattern and transferred to the recording medium.
  • the electron beam of the tube has to be deflected horizontally and vertically.
  • the individual luminous dots are smaller than the raster dots to be recorded on the recording medium, so that the luminous dots to be transmitted must be enlarged by the optical system. But this also increases all blurring of the luminous dots, so that there is a blurred imprint of the image to be recorded on the recording medium.
  • the luminous dot to be transmitted loses significantly more brightness.
  • An increase in the beam current of the cathode ray tube can somewhat alleviate these disadvantages but cannot avoid them.
  • Another disadvantage is that the record carrier has to be stopped by the cathode ray tube during character transmission. It must therefore be transported in start-stop mode. This means a relatively high energy consumption and a large technical effort, which is subject to high wear.
  • the invention has for its object to provide a method and an arrangement for the electrophotographic representation of characters and images with which the individual light points of the cathode ray tube can be generated with a relatively small beam current and still have a sufficiently good brightness bypassing the use of contact exposure by optical fibers so that a latent image with good resolution is obtained on the recording medium.
  • each individual raster line of the same information content of the mosaic-like charge image to be recorded is generated separately by the cathode beam controlled according to the stored information on the screen of the cathode ray tube and transmitted to the recording medium by means of an optical imaging system and recorded there and in which this cathode beam passes over the same raster line on the screen several times in succession with a line frequency that is higher than the minimum line frequency, the recording medium being moved continuously.
  • the activated luminous dots of the cathode ray tube are shown vertically shifted on the record carrier with each subsequent scan. Thus, no individual points are created, but rather small lines formed from several overlapping points. The length of these lines depends on the number and speed (frequency) of scanning the cathode ray over the same line and on the transport speed of the recording medium.
  • the luminous dots of the raster line are displayed on the screen in the size of the raster dots to be imaged on the recording medium.
  • the optical system used therefore only has the task of deflecting and focusing the light rays emitted by the screen onto the recording medium without enlarging the grid pattern, so that a "1: 1 transmission" from the cathode ray tube to the recording medium takes place.
  • a cathode ray tube is used to carry out this method, the screen of which is very low and the height of which is therefore considerably smaller than its width.
  • only a single deflection system is provided, which deflects the cathode beam horizontally.
  • a small vertical line formed from a plurality of overlapping raster points is generated as a raster, which the human eye will practically regard as a point.
  • the screen can be coated with a relatively coarse-grained, highly efficient luminous phosphor.
  • FIG. 1 An electrophotographic printer is shown in FIG. All the necessary structural units are accommodated in a housing 17. With the help of a cathode ray tube 8, which is connected with its connection 11 to the associated electronics (not shown), digitally stored alphanumeric or graphic information is made visible on its screen 9 and this optical light image via an optical system that consists of the mirrors 12 and 14 and the lens 13 is transferred to an endless recording medium 1, for example a drum or tape, with a photoconductive layer. This creates a latent charge image in the recording area 15 on the recording medium 1 which corresponds to the information to be recorded.
  • the record carrier rotates continuously in the direction of the arrow.
  • the latent charge image is developed in a developer station 2 and transferred to a normal paper 4 in the transfer station 3. This paper 4 is withdrawn from a removal compartment 5 and after the transfer of the latent image and its development and fixing in the fixing station 18 in one Storage compartment 6 filed. After the transfer, the recording medium 1 is cleaned and cleaned of the latent image in the cleaning station 7.
  • a tube shown in FIG. 2 with a quite flat rectangular screen 9 with a length L of approximately 210 mm is used as the cathode ray tube 8. This corresponds approximately to the width of an A4 page.
  • the height H is approximately 20 mm.
  • the cathode ray deflected only horizontally by the deflection system 10 sweeps a red dot area 16, the height of which corresponds approximately to the diameter of the halftone dots that are to be recorded on the recording medium 1. Only one raster line of the information to be displayed is always displayed in this area.
  • a raster line is understood to be a raster dot line of all characters to be printed on the A4 page.
  • the same raster line display is shown several times, preferably at least three times, on the screen 9, ie the illuminated area is covered several times with the same line content by the cathode ray.
  • the beam can either activate the illuminated dot area 16 either in the same direction or during forward and backward deflection M ehrfachdar ein same raster line information happens to the line frequency, thereby increasing the sweep speed of the electron beam in the tube.
  • the saturation of the luminous phosphors on the screen of the tube is alleviated.
  • a greater brightness of the phosphor layer of the screen 9 is achieved, so that the latent image recorded on the recording medium 1 is more intense.
  • the screen 9 of the cathode ray tube 8 is covered with a highly efficient phosphor layer, e.g. with a zinc-cadmium sulfide to which copper has been added.
  • a highly efficient phosphor layer e.g. with a zinc-cadmium sulfide to which copper has been added.
  • Such a layer achieves a high brightness of the luminous dots with a relatively low beam current of the cathode ray tube.
  • the luminous efficiency of the phosphor used is 15% instead of only 2 to 5%.
  • the ZnS-type phosphors have a high luminous efficiency with a small beam current, but they reach the saturation range very quickly as the load increases. However, this range can be shifted very far towards high beam currents by increasing the line frequency. This will reduce the recording speed slightly, but more. Controlling the tube several times with the same information content, namely with a certain raster line, results in an undistorted reproduction of the information.
  • the invention was tested in a model, based on the following values:
  • the minimum line frequency V is 1.65 kHz, that is to say when the illuminated dot area is swept once, 16 per raster line (lower curve in FIG. 3). It was shown that the desired light output P 'could not be achieved.
  • the line frequency ⁇ was increased by a factor of 3, ie covering the same light spot area 16 three times, there was a frequency of 4.95 kHz with a luminous efficacy of 60 mW. All that was required was an anode current Ia of 43 / uA (middle curve in FIG. 3). With a further increase in the line frequency ⁇ by a factor of 6, ie six times sweeping over the light spot area 16, to 9.9 kHz, only 30 / uA beam current Ia was required (upper curve in FIG. 3).
  • a sufficient service life of the phosphor layer of the screen 9 is achieved when the beam over the whole of a DIN A4 page reaching raster line by approximately half the spot diameter is set from about 50 / um vertically after each printing operation. After a total offset of approximately 3 mm, the return to the starting line can take place, whereupon the vertical deflection cycle begins again.
  • This gives a screen area (illuminated area 16) of 0.3 ⁇ 20 cm 6 cm 2 , which, with the above values, leads to a beam power density of approx. 0.15 to 0.2 W / cm 2 .
  • This power density corresponds to a service life of far more than 1000 hours for the cathode ray tube.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)
  • Exposure Or Original Feeding In Electrophotography (AREA)
  • Combination Of More Than One Step In Electrophotography (AREA)
  • Facsimile Scanning Arrangements (AREA)
EP82200244A 1981-03-04 1982-02-26 Procédé et appareil pour la présentation électrophotographique d'information Expired EP0059514B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19813108115 DE3108115A1 (de) 1981-03-04 1981-03-04 Verfahren und andordnung zur elektrophotografischen darstellung von informationen
DE3108115 1981-03-04

Publications (3)

Publication Number Publication Date
EP0059514A2 true EP0059514A2 (fr) 1982-09-08
EP0059514A3 EP0059514A3 (en) 1982-12-08
EP0059514B1 EP0059514B1 (fr) 1985-06-05

Family

ID=6126290

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82200244A Expired EP0059514B1 (fr) 1981-03-04 1982-02-26 Procédé et appareil pour la présentation électrophotographique d'information

Country Status (5)

Country Link
US (1) US4571604A (fr)
EP (1) EP0059514B1 (fr)
JP (1) JPS57188176A (fr)
CA (1) CA1176692A (fr)
DE (2) DE3108115A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4706130A (en) * 1983-08-08 1987-11-10 Canon Kabushiki Kaisha Image recording apparatus utilizing light emitting diodes with pixel shape correction

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4499501A (en) * 1982-09-01 1985-02-12 Tektronix, Inc. Image transfer method and apparatus
US4746940A (en) * 1986-11-25 1988-05-24 E. I. Du Pont De Nemours And Company Line scanner to reduce banding
US4816863A (en) * 1986-11-25 1989-03-28 E. I. Du Pont De Nemours And Company Exposure control system for continuous tone electrophotographic film
DE3715363A1 (de) * 1987-05-08 1988-11-24 Jens Rauch Kopiergeraet mit bestueckung einer computeransteuerbaren kopierfaehigen anzeigeeinheit
US4999791A (en) * 1988-12-23 1991-03-12 Schumann Robert W Computer graphics color film recording method and apparatus

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL300963A (fr) * 1962-11-26
US3277237A (en) * 1963-11-29 1966-10-04 Itt Printing cathode ray tube using photoconductive layer
US3653064A (en) * 1968-02-25 1972-03-28 Canon Kk Electrostatic image-forming apparatus and process
US3619484A (en) * 1968-05-24 1971-11-09 Matsushita Electric Industrial Co Ltd A color facsimile scanning system
NL7005408A (fr) * 1969-04-15 1970-10-19
JPS49119630A (fr) * 1973-03-15 1974-11-15
GB1582954A (en) * 1976-06-28 1981-01-21 Crosfield Electronics Ltd Printing methods and apparatus
JPS5911113B2 (ja) * 1979-04-20 1984-03-13 富士通株式会社 電子写真式記録装置
JPS56156855A (en) * 1980-05-09 1981-12-03 Hitachi Ltd Print control system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4706130A (en) * 1983-08-08 1987-11-10 Canon Kabushiki Kaisha Image recording apparatus utilizing light emitting diodes with pixel shape correction

Also Published As

Publication number Publication date
JPS57188176A (en) 1982-11-19
US4571604A (en) 1986-02-18
JPH0335864B2 (fr) 1991-05-29
DE3263986D1 (en) 1985-07-11
EP0059514B1 (fr) 1985-06-05
EP0059514A3 (en) 1982-12-08
DE3108115A1 (de) 1982-09-16
CA1176692A (fr) 1984-10-23

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