WO1994022059A1 - Dispositif de charge a fil chauffe - Google Patents

Dispositif de charge a fil chauffe Download PDF

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Publication number
WO1994022059A1
WO1994022059A1 PCT/NL1993/000067 NL9300067W WO9422059A1 WO 1994022059 A1 WO1994022059 A1 WO 1994022059A1 NL 9300067 W NL9300067 W NL 9300067W WO 9422059 A1 WO9422059 A1 WO 9422059A1
Authority
WO
WIPO (PCT)
Prior art keywords
imaging
corona emitter
emitter
corona
temperature
Prior art date
Application number
PCT/NL1993/000067
Other languages
English (en)
Inventor
Dorron Levy
Original Assignee
Indigo N.V.
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 Indigo N.V. filed Critical Indigo N.V.
Priority to PCT/NL1993/000067 priority Critical patent/WO1994022059A1/fr
Publication of WO1994022059A1 publication Critical patent/WO1994022059A1/fr

Links

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
    • G03G15/02—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices
    • G03G15/0291—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices corona discharge devices, e.g. wires, pointed electrodes, means for cleaning the corona discharge device
    • 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
    • G03G15/02—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices
    • G03G15/0258—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices provided with means for the maintenance of the charging apparatus, e.g. cleaning devices, ozone removing devices G03G15/0225, G03G15/0291 takes precedence

Definitions

  • the present invention relates to charging devices using corona wire in general, and especially to such charging devices used in electrostatographic printers and copiers.
  • BACKGROUND OF THE INVENTION Charging devices are often used in electrostatographic imaging apparatus to charge a photoreceptor. Initially, a photoreceptor surface is charged to a uniform high potential by a charging device. The charge potential can be positive or negative, depending on the type of photoreceptor used.
  • the Corotron and the Scorotron are two common types of photoreceptor chargers that employ an electrified corona wire to deposit charged particles on the surface of the photoreceptor in order to charge it.
  • a wire charged to a high voltage is placed close to the photoreceptor.
  • the Scorotron includes an electrically biased grid between the charged corona wire and the photoreceptor surface, whereby the bias level controls the charge level on the photoreceptor.
  • Research Disclosure 20321 describes a method of cleaning contaminants of airborne particles built up on corona wire in a powder toner system. When the imaging system is not in operation, the wire is directly heated by passing an alternating current through it to a temperature of 350 degrees Fahrenheit (about 177 degrees Celsius), thereby oxidizing deposited powder toner contaminants and reducing them to ash. Additionally, vibrations, caused by the electric fields of the alternating current, aid in shaking the contaminants off the wire.
  • 59058453 discloses a method stabilizing the temperature surrounding a corona wire in an imaging system to a temperature range between 10 and 35 degrees Celsius in order to obtain a stable electrified state on the photosensitive drum surface and a uniform image irrespective of an environmental change in temperature.
  • heated air is blown at the wire.
  • German Patent Publication No. 3132047 teaches an electrostatic dust filter including a corona wire which charges dust particles which are deposited on oppositely charged filter electrodes. The corona wire is heated by continuously passing an electric current through it during the operation of the filter to limit the production of ozone.
  • the present inventor has found that when liquid toner is used , corona wire contamination occurs .
  • Thi s contamination is different from that in powder toner systems ( and is unexpected ) since in liquid toner systems there is no deposition of solid toner material on the wire .
  • the source of contamination in liquid toner systems appears to be carrier l iquid which evaporates during the imaging process and re-deposits on the corona wire.
  • This deposited carrier liquid in the presence of corona forms a coating on the wire which appears to include at least parti al ly polymerized carrier liquid .
  • This contamination causes increased probability of sparking and changes the emission properties of the wire . To avoid these undes irable qualities , periodic replacement of the corona wire i s required.
  • the apparatus of the present invention preferably includes a high voltage power supply attached to a floating heater power supply which is connected to the corona wire.
  • the heater power supply heats the corona wire by means of resistive (Joule) heating.
  • the corona wire is raised preferably to a temperature of 100 to 300 degrees Celsius, more preferably to 200 degrees Celsius, a temperature above 50 degrees Celsius is helpful in carrying out the invention. At these temperatures the technique successfully reduces contaminant accumulation by minimizing the adsorption of organic materials to the surface of the corona wire. Furthermore, polymerization is unlikely under these conditions. By heating the corona wire from room temperature to 100 degrees Celsius it is also observed that the production of ozone is reduced substantially.
  • the advantages of some aspects of the present invention over prior art include minimizing downtime of the imaging system by use of the heating apparatus that works concurrently with the power supply during operation of the imaging apparatus. Furthermore such operation, with liquid toner, avoids contamination buildup and ash production. There are no vibrations resulting from the preferred use of direct current as exist when using alternating current.
  • ozone production is substantially reduced by heating the corona wire to a sufficient temperature.
  • the corona wire is heated to a temperature higher than the temperature of its surroundings during operation of the imaging machine. Depending on the temperature, the advantages of the invention are achieved to differing degrees.
  • Charging devices of the present invention are suitable for use in other charging operations such as the charging of paper to effect the transfer of toner thereto, and are also suitable for use in powder toner systems both for photoreceptor charging and image transfer.
  • BRIEF DESCRIPTION OF THE DRAWINGS The present invention wi l l be understood and appreciated more fully from the following description taken in conjunction with the drawings in which: Fig . 1 is a schematic cross-sectional drawing of an imaging system; and Fig . 2 shows a schematic drawing of the heated wire charging device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Fig . 1 shows a general plan of an imaging system in accordance with a preferred embodiment of the present invention .
  • a drum 10 having a photoreceptor surface 12 is rotated by any suitable means (not shown ) about an axle 14 in a direction indicated by arrow 16.
  • Photoreceptor 12 first passes a charger 18 , which may be a Corotron or, preferably, a Scorotron, which is adapted to charge the photoreceptor to a relatively high voltage, typically 1000 volts .
  • a charger 18 which may be a Corotron or, preferably, a Scorotron, which is adapted to charge the photoreceptor to a relatively high voltage, typically 1000 volts .
  • Both the Corotron and the Scorotron employ a corona wire to charge photoreceptor 12 by depositing charged particles at its surface .
  • Other charging methods which use corona wire are also suitable for use with the present invention.
  • Photoreceptor 12 next passes an exposure device 20. Any method known in the art for producing a latent electrostatic image on a photoreceptor can be used , including exposure by a scanning laser system or by an array of LED devices or to a reflection from a copy sheet. Other methods are also suitable . If an electrostatic master is used, the exposure device is omitted .
  • the latent image on photoreceptor 12 is developed by a developer 22.
  • Developer 22 can be of any convenient type known in the art, preferably using liquid toners, although the invention is also useful in powder toner systems .
  • the developed image produced by developer 22 is transferred to a final substrate at a transfer station 24.
  • Transfer station 24 may be of any suitable type known in the art and may operate by direct transfer to the final substrate or by transfer via an intermediate transfer member. If transfer to the substrate includes charging the substrate with a Corotron or Scorotron, a Corotron or Scorotron according to the invention is preferred.
  • some toner may remain on the photoreceptor.
  • cleaning station 26 which is next on the route of photoreceptor 12, the remains of the developed image are removed.
  • a discharge system 28 completes the cycle.
  • discharge system 28 comprises a lamp or a series of lamps, which illuminate the photoreceptor and remove any remaining charge on the photoreceptor.
  • Other systems for removing charge as are known in the art are also suitable for use in the invention.
  • the photoreceptor, after passing discharge system 28 is completely discharged and is ready for the next cycle. All of the steps and apparatus thus far described (except for charger 18 and transfer station 24) are purely conventional and perform the same functions which they perform in conventional systems.
  • Fig. 2 shows a simplified schematic of a corona wire 30 which is electrified to a high voltage power supply 32.
  • a heater power supply 34 which is preferably electrically floating is preferably activated when the high voltage power supply 32 is activated.
  • the corona wire 30 is thus heated, preferably between 100 and 300 degrees Celsius, more preferably to 200 degrees Celsius, although in general, heating the wire to temperatures above room temperature or above the surroundings of the wire are useful.
  • heating the corona wire prevents carrier liquid in the liquid toner from adhering to the corona wire 30. Heating the corona wire also reduces ozone accumulation.
  • control of the power supply 34 can be achieved by means of opto- couplers as used in many high voltage instruments. It will be appreciated by persons skilled in the art that the present invention is not limited by what has been described hereinabove . Rather the scope of the present invention is defined only by the following claims :

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • General Physics & Mathematics (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)

Abstract

Appareil de réduction de la contamination d'un émetteur à effet couronne (30) pendant une opération de formation d'image dans un appareil de formation d'images comprenant une source de haute tension (32) servant à exciter l'émetteur à effet couronne (30) pendant l'opération de formation d'image, et une source d'alimentation (34) en énergie de chauffage servant à porter l'émetteur à effet couronne (30) à une température supérieure à la température environnante pendant l'opération de formation d'image.
PCT/NL1993/000067 1993-03-23 1993-03-23 Dispositif de charge a fil chauffe WO1994022059A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/NL1993/000067 WO1994022059A1 (fr) 1993-03-23 1993-03-23 Dispositif de charge a fil chauffe

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/NL1993/000067 WO1994022059A1 (fr) 1993-03-23 1993-03-23 Dispositif de charge a fil chauffe

Publications (1)

Publication Number Publication Date
WO1994022059A1 true WO1994022059A1 (fr) 1994-09-29

Family

ID=19861913

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NL1993/000067 WO1994022059A1 (fr) 1993-03-23 1993-03-23 Dispositif de charge a fil chauffe

Country Status (1)

Country Link
WO (1) WO1994022059A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6562539B1 (en) 1999-07-05 2003-05-13 Indigo N.V. Printers and copiers with pre-transfer substrate heating
WO2015034523A1 (fr) 2013-09-06 2015-03-12 Hewlett-Packard Development Company, L.P. Impression électrographique de liquide

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3496352A (en) * 1967-06-05 1970-02-17 Xerox Corp Self-cleaning corona generating apparatus
US3621244A (en) * 1969-06-24 1971-11-16 Katsuragawa Denki Kk Corona discharge device with means to heat the discharge electrodes to increase the discharge current
US3845307A (en) * 1973-02-22 1974-10-29 Xerox Corp Combined corona and luminescent discharge
US4511244A (en) * 1983-09-06 1985-04-16 Eastman Kodak Company Corona generating apparatus and method
JPS6127570A (ja) * 1984-07-18 1986-02-07 Canon Inc 放電装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3496352A (en) * 1967-06-05 1970-02-17 Xerox Corp Self-cleaning corona generating apparatus
US3621244A (en) * 1969-06-24 1971-11-16 Katsuragawa Denki Kk Corona discharge device with means to heat the discharge electrodes to increase the discharge current
US3845307A (en) * 1973-02-22 1974-10-29 Xerox Corp Combined corona and luminescent discharge
US4511244A (en) * 1983-09-06 1985-04-16 Eastman Kodak Company Corona generating apparatus and method
JPS6127570A (ja) * 1984-07-18 1986-02-07 Canon Inc 放電装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 10, no. 180 (P - 471)<2236> 24 June 1986 (1986-06-24) *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6562539B1 (en) 1999-07-05 2003-05-13 Indigo N.V. Printers and copiers with pre-transfer substrate heating
WO2015034523A1 (fr) 2013-09-06 2015-03-12 Hewlett-Packard Development Company, L.P. Impression électrographique de liquide
EP3042247A4 (fr) * 2013-09-06 2017-04-12 Hewlett-Packard Development Company, L.P. Impression électrographique de liquide
US9678454B2 (en) 2013-09-06 2017-06-13 Hewlett-Packard Development Company, L.P. Liquid electrography printing
US9952527B2 (en) 2013-09-06 2018-04-24 Hewlett-Packard Development Company, L.P. Liquid electrography printing

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