EP0223693A2 - Entwicklungseinrichtung für Plotter - Google Patents

Entwicklungseinrichtung für Plotter Download PDF

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Publication number
EP0223693A2
EP0223693A2 EP86402471A EP86402471A EP0223693A2 EP 0223693 A2 EP0223693 A2 EP 0223693A2 EP 86402471 A EP86402471 A EP 86402471A EP 86402471 A EP86402471 A EP 86402471A EP 0223693 A2 EP0223693 A2 EP 0223693A2
Authority
EP
European Patent Office
Prior art keywords
toner
sheet
roller
chamber
disposed
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Withdrawn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
EP86402471A
Other languages
English (en)
French (fr)
Other versions
EP0223693A3 (de
Inventor
Robert L. Nieto
Joseph Camacho
Douglas Hardy
Peter Kamas
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.)
Benson Inc
Original Assignee
Benson Inc
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 Benson Inc filed Critical Benson Inc
Publication of EP0223693A2 publication Critical patent/EP0223693A2/de
Publication of EP0223693A3 publication Critical patent/EP0223693A3/de
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
    • G03G15/0105—Details of unit
    • G03G15/0121—Details of unit for developing
    • 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
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/10—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer
    • 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
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/10—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer
    • G03G15/11—Removing excess liquid developer, e.g. by heat

Definitions

  • This invention relates generally to electro­static plotting and in particular, to a station in an electrostatic plotter where toner is applied to paper or other material.
  • a writing head which includes a large number of closely spaced electrodes (for example, 200 per inch), is positioned in proximity to a sheet of paper or other material.
  • Another electrode usually known as a "backplate,” is positioned behind the paper or adjacent to the writing head.
  • a potential applied between selected ones of the electrodes in the writing head and the backplate causes charge to accumulate on the paper.
  • Toner applied to the paper adheres electrostatically to these charged regions, while undesired toner is then vacuumed off the paper, or otherwise removed.
  • the paper travels between a supply reel and a take-up reel. Between the two reels a single writing head is positioned in a location where charge may be applied to the paper as it passes the writing head. After passing the writing head the paper traverses four toning stations, one of which will be activated to apply a particular color to the paper. Following that application, the paper is rewound onto the supply reel, then pulled across the writing head where further charge is applied, then another toner station raised into position to contact the paper and apply a second color. The process is repeated four times for a full-color image (yellow, cyan, magenta, and black). This technology is termed “single station mutiple pass printing" because only a single writing head is used and multiple passes of the paper are made across the writing head to create the ultimate image.
  • Single station multiple pass electrostatic plotters suffer from several disadvantages.
  • One significant disadvantage is that the finished image is produced much more slowly than desired because of the need to roll and unroll the paper once for each color employed in the image.
  • Such plotters require mechanisms for raising and lowering each toner station in proximity with the paper.
  • maintaining alignment among each of the four images printed on successive passes is difficult.
  • the paper must be precisely repositioned, with proper account for any stretching, shrinkage, or other dimensional changes.
  • the electrostatic printer head must be rigidly mounted to maintain its aligment continuously. This requires bulky stiffeners, channels and the like.
  • This invention provides a compact station for electrostatic plotting, which in the preferred embodiment includes a writing head for applying electrostatic charge to a sheet of material, a toner roller for applying toner of selected color to the sheet of material after the electrostatic charge, and a vacuum station for removing excess toner from the sheet.
  • the toner roller is mounted in a trough to capture excess toner sprayed onto the roller and to enable the excess toner to be recycled.
  • the vacuum chamber and trough are integrally formed and affixed to the writing head to provide rigidity, and eliminate the need for prior art channels, stiffeners, or other mechanical alignment devices.
  • the toner station of this invention provides a substantially more compact station than prior art electrostatic plotters, thereby enabling the fabrication of an overall compact plotter which can fit through an ordinary doorway, yet create E size drawings.
  • the combined toner roller and vacuum chamber assembly provides rigidity to the writing head to maintain alignment while preventing, bowing, warping, or other distortion.
  • the toner station is modular, enabling the same station construction to be used for each color of a multiple color plotter.
  • the structure of the station enables independent control of the amount of toner applied to the roller, the speed of rotation of the toner roller, and the pressure of the vacuum system, enabling each station to be precisely tuned for the characteristics of the particular toner chosen for that station.
  • Figure 1 is a cross-sectional view of a oreferred embodiment of the toner station of our invention.
  • the station includes an electrostatic writing head l0 for applying charge to a sheet of material l5, typically paper, which passes over the writing head l0.
  • the paper is caused to pass across the writing head and other apparatus depicted in the Figure, for example, by a friction drive mechanism (not shown). Alignment of the paper with the writing heads is achieved by marking the paper at the first head, then detecting the location of the marks at each subsequent head.
  • the electrostatic charge is applied to paper l5 by a network of electrodes formed within the writing head l0.
  • the writing electrodes comprise a network of fine parallel wires l6 which extend to the upper surface l7 of head l0.
  • Also fabricated on the surface of head l0 are a larger series of electrodes l9 (See Figure 1A). By applying appropriate electrical signals between electrodes l6 and l9 charge may be deposited on paper l5.
  • toner applied in a subseqent operation will adhere to the charged regions on the paper until a solvent within the toner evaporates and fixes the image. Toner applied to uncharged regions will be removed before the solvent evaporates.
  • By pulsing the potential applied across selected ones of electrodes l6 and l9 small "dots" of charge are applied to the paper, and a half-toned image may be created from three primary colors--cyan, yellow, and magenta. To enhance the quality of the image, however, black, is employed.
  • Paper l5 is held in close proximity to head surface l7 by a roller 22 rotating on shaft 24.
  • the outer surface of roller 22 is generally fabricated from a resilient material, for example, foam rubber, to allow the roller to deform while applying suitable pressure to the sheet l5.
  • a printed circuit board 25, or other well-known apparatus, is used to interconnect the electrodes in head l0 to other control apparatus in the electrostatic plotter.
  • writing head l0 is fabricated from epoxy, fiberglass, or other dimensionally stable material to minimize thermal changes in the spacings of the individual electrodes l6.
  • head l0 includes about 9,000 wires l6 and is approximately 38" long.
  • Such heads are commercially available, and have been the subject of many patents.
  • electrostatic printing heads such as a printing head l0
  • a printing head l0 tend to flex, warp, or bow, in response to stresses applied by the framework in which the head is mounted, the frictional forces applied by the paper moving past the head, as well as other effects, including thermal expansion and contrac­tion.
  • the writing electrode l6 To maintain precise alignment of the writing electrode l6, such dimensional variations must be minimized. Any such change in head orientation can create lines or other undesirable effects in the ultimately created image. Accordingly, the writing heads must be mounted in a manner as to minimize dimensional or orientational changes.
  • the electrostatic writing head l0 is affixed to an integral toner application and removal apparatus 28.
  • Assembly 28 is affixed to head l0 by being bolted, screwed or otherwise attached to a bar 30, on head l0.
  • Bar 30, typically aluminum or other metal, is typically provided as a part of head l0 by the manufacturer of head l0. By itself bar 30 does not provide sufficient rigidity.
  • Assembly 28 includes two primary components, a toner roller 35 and a vacuum chamber 40. Toner is applied to roller 35, and in turn to paper l5. Excess toner applied to the paper is removed by chamber 40 in manner described in further detail below.
  • toner is used herein, it should be understood that it is being used in a generic sense to describe generally liquid material which may contain dyes for producing colored images.
  • Toner roller 35 rotates on shaft 37.
  • the exterior surface of roller 35 includes a series of ridges 38 which are sufficiently closely spaced that capillary action allows toner 40 to adhere to the exterior surface of roller 35 and forms a thin film over ridges 38 (see Figure 1B).
  • ridges 38 which are sufficiently closely spaced that capillary action allows toner 40 to adhere to the exterior surface of roller 35 and forms a thin film over ridges 38 (see Figure 1B).
  • Sprayer 44 consists of a tube having a longitudi­nal axis substantially parallel to the axis of rotation of shaft 37. A series of very small closely spaced openings are drilled through the wall of tube 44 to allow toner pumped into tube 44 under pressure to spray out onto the exterior surface of roller 35. Toner in excess of that adhering to the surface of roller 35 is removed by a drain 47 and recycled. Typically, a flexible plastic tube or other suitable plumbing is coupled between drain 47 and a reservoir of toner (not shown).
  • Vacuum chamber 40 Positioned adjacent to roller 35 is a vacuum chamber 40 having openings 48 in its upper surface. Vacuum chamber 40, together with openings 48, removes excess toner from paper l5. Excess toner will typically be present on sheet l5 because roller 35 continuously applies toner to the sheet, regardless of whether writing electrodes l6 and l9 are active. Even if the writing heads are active, undesired toner is applied between the "dots" of charge, and this toner must be removed.
  • vacuum chamber 40 By maintaining vacuum chamber 40 at less than atmospheric pressure, excess toner on sheet l5 will be sucked through openings 48 into chamber 40.
  • One or more drains 49 in the lower portions of chamber 40 allow the excess toner to be recycled, in the same manner as toner removed from drain 47.
  • the drain(s) 49 also allow connection of hoses between chamber 40 and a vacuum pump, or other suitable apparatus for maintaining less than ambient pressure.
  • vacuum is used throughout this application, it will be under­stood, of course, that by virtue of openings 48, chamber 40 will not provide a vacuum per se, but will instead provide a region of reduced atmospheric pressure to allow suction of toner from sheet l5.
  • extrusion 60 is grounded. In this manner, any excess untoned electrostatic charge present on paper l5 will be removed, thereby enabling complete removal of undesired toner by the vacuum station.
  • toner station of this invention is the use of a single extrusion 60 to provide rigid aligment of the writing head l0, a trough and support for the toner application roller 35, and a vacuum chamber 40.
  • each of these components was separately fabricated and assembled.
  • end plates necessary to seal the ends of chamber 40 and trough 55, as well as provide the necessary support for sprayer 44 and for the bearings for shaft 37.
  • FIG 2 is a top view of the apparatus shown in Figure 1, but in which the paper l5 has been cut away to illustrate the underlying structure.
  • writing head l0 extends laterally across the full width of sheet l5 and includes in its upper surface a large number of electrodes l6 and l9.
  • Toner roller 35 is also shown with its grooved exterior surface 38.
  • the upper surface of the vacuum chamber 40 with openings 48 is depicted, as well as end plates 62.
  • the small electric motor and drive belt used to rotate roller 35. By employing a voltage dependent motor, the speed of rotation of roller 35 may be adjusted to suit each application.
  • Figure 3 is a cross-sectional view of a single-pass multiple station electrostatic printer illustrating the manner in which four stations 70,7l, 72 and 73, may be combined into an integral unit for the making of large color plots in a single pass, yet on a machine less than 36" wide.
  • the apparatus depicted in Figure 3 includes a frame 65 for supporting the four station and auxilliary equipment such as the toner reservoirs.
  • the paper upon which the image is to be plotted is wound on a roll (not shown) along the left side of the machine, then passes from left to right in Figure 3.
  • a protrusion 74 from frame 65 provides an axis for rotation of a lid (not shown) which covers the upper surface of the structure.
  • Each station includes a roller 22 for pressing the sheet of material into contact with the upper surface of the writing head l0. As discussed above, each roller 22 rotates about a shaft 24 and includes a resilient exterior surface for pressing paper against the supper surface.
  • the second toner station 7l depicts a drive belt 75 for driving toner-roller 35.
  • the precise location of the drive motor is adjusted by the elongated slots in plate 78.
  • the location of threaded openings 8l is also shown for attaching the end plate to the extrusion 60, for example, with bolts and a gasket.
  • Each station is similar equipped.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)
  • Pens And Brushes (AREA)
  • Electrophotography Using Other Than Carlson'S Method (AREA)
EP86402471A 1985-11-04 1986-11-04 Entwicklungseinrichtung für Plotter Withdrawn EP0223693A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US79491085A 1985-11-04 1985-11-04
US794910 1991-11-20

Publications (2)

Publication Number Publication Date
EP0223693A2 true EP0223693A2 (de) 1987-05-27
EP0223693A3 EP0223693A3 (de) 1989-12-13

Family

ID=25164060

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86402471A Withdrawn EP0223693A3 (de) 1985-11-04 1986-11-04 Entwicklungseinrichtung für Plotter

Country Status (2)

Country Link
EP (1) EP0223693A3 (de)
JP (1) JPS62187867A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0657786A1 (de) * 1993-12-10 1995-06-14 Hewlett-Packard Company Verfahren und Vorrichtung zur Entwicklung mit Reduktion des Streufeld-Randeffektes in der Flüssigtoner-Elektrophotographie
DE102004061961A1 (de) * 2004-12-23 2006-07-13 CSAT Gesellschaft für Computer-Systeme und Automations-Technik mbH Vorrichtung zum elektrographischen Drucken oder Kopieren unter Verwendung flüssiger Farbmittel

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5078088A (en) * 1989-10-11 1992-01-07 Olympus Optical Co., Ltd. Roller type liquid developing apparatus

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3859960A (en) * 1970-11-27 1975-01-14 Versatec Printing machine with electrostatic web developing apparatus
US3921580A (en) * 1974-06-12 1975-11-25 Varian Associates Liquid development of electrostatic images
EP0026654A2 (de) * 1979-09-28 1981-04-08 Xerox Corporation Flüssigkeitsentwicklungsauftragvorrichtung
EP0153422A1 (de) * 1984-02-09 1985-09-04 Fuji Photo Film Co., Ltd. Elektrophotographische Vorrichtung
JPS62239168A (ja) * 1986-04-11 1987-10-20 Fuji Xerox Co Ltd 静電記録装置
US4734788A (en) * 1986-09-05 1988-03-29 Benson, Inc. Single pass electrostatic color printer/plotter having straight paper path

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3859960A (en) * 1970-11-27 1975-01-14 Versatec Printing machine with electrostatic web developing apparatus
US3921580A (en) * 1974-06-12 1975-11-25 Varian Associates Liquid development of electrostatic images
EP0026654A2 (de) * 1979-09-28 1981-04-08 Xerox Corporation Flüssigkeitsentwicklungsauftragvorrichtung
EP0153422A1 (de) * 1984-02-09 1985-09-04 Fuji Photo Film Co., Ltd. Elektrophotographische Vorrichtung
JPS62239168A (ja) * 1986-04-11 1987-10-20 Fuji Xerox Co Ltd 静電記録装置
US4734788A (en) * 1986-09-05 1988-03-29 Benson, Inc. Single pass electrostatic color printer/plotter having straight paper path

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
BUREAUX D'ETUDES AUTOMATISMES, vol. 30, no. 29, November 1986, pages 22,24,26, Paris, FR; J.-F. PREVERAUD: "Tracé électrostatique simple passe: compenser les déformations" *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0657786A1 (de) * 1993-12-10 1995-06-14 Hewlett-Packard Company Verfahren und Vorrichtung zur Entwicklung mit Reduktion des Streufeld-Randeffektes in der Flüssigtoner-Elektrophotographie
DE102004061961A1 (de) * 2004-12-23 2006-07-13 CSAT Gesellschaft für Computer-Systeme und Automations-Technik mbH Vorrichtung zum elektrographischen Drucken oder Kopieren unter Verwendung flüssiger Farbmittel
DE102004061961B4 (de) * 2004-12-23 2006-09-21 CSAT Gesellschaft für Computer-Systeme und Automations-Technik mbH Vorrichtung zum elektrographischen Drucken oder Kopieren unter Verwendung flüssiger Farbmittel

Also Published As

Publication number Publication date
EP0223693A3 (de) 1989-12-13
JPS62187867A (ja) 1987-08-17

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