EP0137188A1 - Appareil de développement pour le développement liquide d'images électrostatiques - Google Patents

Appareil de développement pour le développement liquide d'images électrostatiques Download PDF

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Publication number
EP0137188A1
EP0137188A1 EP84109344A EP84109344A EP0137188A1 EP 0137188 A1 EP0137188 A1 EP 0137188A1 EP 84109344 A EP84109344 A EP 84109344A EP 84109344 A EP84109344 A EP 84109344A EP 0137188 A1 EP0137188 A1 EP 0137188A1
Authority
EP
European Patent Office
Prior art keywords
developing electrode
electrode
development
developing
image carrier
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
EP84109344A
Other languages
German (de)
English (en)
Other versions
EP0137188B1 (fr
Inventor
Erwin Dr. Lind
Helmuth Haberhauer
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.)
Hoechst AG
Original Assignee
Hoechst AG
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 Hoechst AG filed Critical Hoechst AG
Publication of EP0137188A1 publication Critical patent/EP0137188A1/fr
Application granted granted Critical
Publication of EP0137188B1 publication Critical patent/EP0137188B1/fr
Expired legal-status Critical Current

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    • 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
    • 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
    • G03G15/101—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer for wetting the recording material

Definitions

  • the invention relates to a developing device for liquid development of electrostatic charge images on an image carrier material, with a device for spraying a liquid developer onto the image carrier material to be developed and with a development electrode connected to a DC voltage source.
  • Such a device for developing an electrostatic charge image on an electrophotographic copying material is known from DE-PS 25 07 221.
  • This device is equipped with a pair of inlet rollers for applying a toner dispersion with toner particles charged opposite to the polarity of the charge image on the copying material, and also with a distributor roller for uniformly distributing the toner dispersion on the charge image.
  • the spray tube for spraying the toner dispersion is mounted above the distributor roller and has rows of nozzles which are arranged symmetrically to the vertical center line of the spray tube in the tube shell.
  • the voltage applied to the distribution roller is at least as large as the charge level at the image areas of a white area of the charge image and not greater than the charge level at the image areas of a full tone area of the charge image.
  • the voltage applied to the distributor roller is preferably in the range between 20 and 350 volts.
  • the distributor roller works as a counter electrode or developing electrode and the toner deposited on the surface of the distributor roller is rinsed off by spraying with the toner dispersion and arrives in a collecting trough in order to be reused.
  • DE-OS 21 38 254 describes an electrophotographic reversal development device with one or more development electrode rollers, which carry a bias with the polarity of the charge image to be developed, and is equipped with devices for supplying toner dispersion to the development electrode rollers.
  • the developing electrode rollers are not in direct contact with the copying material and the toner particles of the toner dispersion used have the same polarity as the charge image.
  • the liquid developer is applied directly to the development electrode rolls, which then passes from the development electrode rolls onto the recording medium.
  • Conductive rollers are arranged below the record carrier, which support the underside of the record carrier. These conductive rolls are cleaned by flexible brushes.
  • a developing device for electrophotographic copying materials is known from German Offenlegungsschrift 23 32 253, which is passed in a development zone under application rollers which are wetted from above with a toner dispersion. In this way, a film of the toner dispersion on the copy material upset. At the end of the development zone there is a pair of squeeze rollers that squeeze away the excess toner dispersion from the surface of the copy material.
  • a developing device which, as an application element for the liquid toner on a recording material carrying charge images, has a roller or an endless belt which can be put into circulation.
  • a device for reducing the amount of liquid carried along by the toner deposited on the application element is arranged at a point on the movement path of the application element between emerging from the developer bath and application to the recording material.
  • This device can be a corona discharge electrode. Excess or residual toner on the application element is removed after development by means of a scraping blade, a rotating brush or other devices.
  • the known developing devices have the disadvantage in common that the toner supply does not take place uniformly under all conditions and that, in particular, the reproduction of full-tone areas which must be homogeneously covered with toner, the basic reproduction of non-image areas and in particular the reproduction of rastered images on the recording materials with correct tonal values leaves.
  • the object of the invention is to provide a development device which enables high-quality liquid development of electrostatic charge images with constant image quality, without the cleaning of the development electrode used for development being necessary.
  • the developing electrode consists of an electrically conductive tape which is unwound from a supply roll and wound on a take-up roll and that the distance of the tape-shaped developing electrode from the surface of the image carrier material is adjustable by means of at least one guide roller, via which the band-shaped developing electrode is guided.
  • the developing electrode is connected to a controllable direct voltage source and is the one pole of the direct voltage source connected to the support over which the image carrier material is moved.
  • the take-up reel is connected to a controllable direct voltage source.
  • the band-shaped developing electrode or the band electrode is guided with the help of one or more rollers.
  • the band-shaped development electrode is guided both in front of the spray tube for the liquid developer and after the spray tube via two adjustable guide rollers. It is expedient to guide the band-shaped development electrode over a deflection roller, which is located above the spray tube. Depending on the number of guide rollers used, a more or less large electrode area is created, so that an adaptation to the properties of the liquid developer used and to process parameters, such as development speed, is easily possible.
  • the distance between the developing electrode and the surface of the image carrier can be adjusted with great accuracy by adjusting the guide rollers.
  • Thin metal foils for example made of aluminum, are suitable as the strip material for the developing electrode, which are bright rolled, roughened on the surface or coated with a high resistance.
  • Metal-coated or metal-clad plastic films or paper can also be used.
  • the advantage is achieved that halftone dots are reproduced with constant tonal value, full-tone areas are developed homogeneously and non-image areas are rendered fundamentally, since a developing electrode is always available for the compensation of the residual charge, on the surface of which faces the image carrier, still no toner has deposited.
  • a developing device 1 according to the invention is shown schematically in FIG. 1.
  • This developing device 1 has a horizontally in one plane support 12 on which the image carrier material 2 to be developed, for example a printing plate, rests or is transported along.
  • the image carrier material 2 or copying material consists of an electrically conductive carrier layer with one thereon applied electrophotographic recording layer which is electrostatically homogeneously charged in a known manner using a corona charging device.
  • the charged recording layer is then exposed imagewise in contact with an original, episcopically or diascopically from an original.
  • the latent electrostatic charge image generated in this way is developed in the developing device 1 with liquid toner, which is toner particles dispersed in a liquid.
  • a pair of inlet rollers 9 and a pair of transport rollers 11 are arranged.
  • the image carrier material 2 to be developed is introduced with the recording layer carrying the electrostatic charge image upward over the base 12 into the nip between the inlet roller pair 9, gripped by these rollers and transported in the direction of arrow A through the developing device 1.
  • a spray tube 3 which contains rows of nozzles in a known manner, each of which is arranged on the tube circumference at an angle between 5 and 15 to the perpendicular. This angular arrangement ensures a particularly uniform distribution of the liquid film on the recording layer of the image carrier material 2.
  • a slot nozzle or other application device can also be provided.
  • a supply roll 7 for a band-shaped developing electrode 6 is arranged above the inlet roller pair 9.
  • the band-shaped developing electrode 6 is an electrically conductive band which is unwound from the supply roll 7 and is guided via a guide roll 10 to a take-up roll 8 which is approximately at the same height as the supply roll 7 above the base 12.
  • the distance of the band-shaped developing electrode 6 from the surface of the image carrier material 2 is adjusted by means of the guide roller 10, the shaft of which can be adjusted within a range of 1 to 3 mm in a manner not shown.
  • the band-shaped developing electrode 6 is advantageously wound up from the supply roll 7 onto the take-up roll 8 at the same speed as the transport speed of the image carrier material 2.
  • This mode of operation of the developing device 1 is only intended if particularly high demands are made on the development and the reproduction of rastered images. If the requirements for the image quality are somewhat lower, it is sufficient if the band-shaped developing electrode stands still during the transport of the image carrier material 2 and several printing plates, for example five to ten pieces, are developed with a section of predetermined length of the developing electrode 6, before the developing electrode 6 this distance of predetermined length is transported. With only five to ten development processes with the same band section of the developing electrode 6, the electrode contamination is retained by deposited Toner in very narrow limits.
  • the development electrode 6 is transported in the direction of arrow B from the supply roll 7 to the take-up roll 8. Of course, it is also possible to transport the development electrode 6 in the opposite direction, ie from the roll 8, which is then provided as a supply roll the roll 7, which then acts as a take-up roll.
  • the distance between the band-shaped developing electrode 6 and the light-sensitive surface is 0.5 mm to 2 mm, although a distance between 1 mm and 1.5 mm is preferred.
  • the thickness of the band-shaped developing electrode 6 is 20 to 100 ⁇ m, in particular 50 ⁇ m, and up to 300 m of the developing electrode 6 can be wound onto the supply roll 7.
  • a metal foil, in particular an aluminum foil, is generally provided as the strip material for the developing electrode 6.
  • the surface of the developing electrode can be roughened, bright rolled or coated with a high resistance.
  • polystyrene or copolymers can be provided, which largely prevent voltage breakdown of the developing electrode 6.
  • the one pole of the controllable direct voltage source 4 is connected to the developing side via a sliding contact (not shown) electrode 6 in connection, which faces the image carrier material 2.
  • a DC voltage of up to about 200 volts is applied to the developing electrode 6.
  • An air nozzle 5 or 13 for drying the image carrier material 2 and the developer electrode 6 is arranged at a distance of 1 to 3 mm from the surface of the image carrier material 2 to be developed or the side of the developing electrode 6 which faces the image carrier material 2.
  • metal foils instead of metal foils, metal-coated or metal-clad plastic foils can also be used for the developing electrode 6.
  • a metal-coated or metal-coated paper web is also suitable as the strip material of the developing electrode.
  • a plurality of guide rollers 14 to 17 are provided, over which the band-shaped developing electrode 6 is guided.
  • the same reference numerals are used for the components of this development device 1 which correspond to corresponding elements of the development device according to FIG. 1. The description of these components is not repeated.
  • the band-shaped developing electrode 6 is moved from the supply roll 7 in the direction of arrow B via the two guide rolls 14 and 15, further via a deflection roll 18 and the two guide rolls 16 and 17 to the take-up roll 8.
  • the guide rollers 14 to 17 are mounted at a distance of approximately 0.5 mm to 2 mm from the surface of the image carrier material 2. The distance between the guide rollers can be set within the specified range.
  • the deflection roller 18 is arranged further away from the image carrier material 2 above the spray tube 3.
  • one pole of the controllable direct voltage source 4 is connected to the roller core of the take-up roll 8, while the other pole is connected to the base 12, over which the image carrier material 2 is transported.
  • the use of two guide rollers in front of the spray tube or in front of the deflection roller 18 and two guide rollers after the spray tube 3, viewed in the transport direction A of the image carrier material 2 results in a larger electrode area for the development, which is caused by the distance between the guide rollers 14 and 15 or 16 and 17 from each other.
  • This electrode area which is larger in comparison to the embodiment according to FIG. 1, enables a very precise adaptation to the properties of the liquid developer used and to process parameters, such as the development speed, i.e. the transport speed of the image carrier material 2 and the band-shaped developing electrode 6, easily possible.
  • the invention i.a. realized a development electrode that is completely free from toner precipitation and thus enables a reproduction of consistent quality for all developed image carrier materials with correct tonal value.
  • there is no need to clean the developing electrode during operation since it can either be thrown away after use or can be cleaned in a single operation if reused.
  • the cost of such a development electrode is low in view of the materials used on the market for this purpose.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Wet Developing In Electrophotography (AREA)
EP84109344A 1983-08-16 1984-08-07 Appareil de développement pour le développement liquide d'images électrostatiques Expired EP0137188B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19833329451 DE3329451A1 (de) 1983-08-16 1983-08-16 Entwicklungsvorrichtung zum fluessigentwickeln von elektrostatischen ladungsbildern
DE3329451 1983-08-16

Publications (2)

Publication Number Publication Date
EP0137188A1 true EP0137188A1 (fr) 1985-04-17
EP0137188B1 EP0137188B1 (fr) 1988-05-18

Family

ID=6206590

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84109344A Expired EP0137188B1 (fr) 1983-08-16 1984-08-07 Appareil de développement pour le développement liquide d'images électrostatiques

Country Status (6)

Country Link
US (1) US4587192A (fr)
EP (1) EP0137188B1 (fr)
JP (1) JPS6057875A (fr)
AU (1) AU567364B2 (fr)
CA (1) CA1220334A (fr)
DE (2) DE3329451A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59207164A (ja) * 1983-05-10 1984-11-24 神鋼電機株式会社 消火ロボツト
US5148639A (en) * 1988-07-29 1992-09-22 Canon Kabushiki Kaisha Surface roughening method for organic electrophotographic photosensitive member
US5893663A (en) * 1997-11-19 1999-04-13 Xerox Corporation Web liquid charging: improved resistance to contamination
CZ309078B6 (cs) * 2018-05-28 2022-01-19 Contipro A.S. Zařízení a způsob výroby nano- a/nebo mikrovlákenných vrstev se zvýšenou tloušťkovou rovnoměrností

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD92858A (fr) *
US2784694A (en) * 1955-02-08 1957-03-12 Haloid Co Segmented development electrode
US3232190A (en) * 1963-06-28 1966-02-01 Ibm Method and apparatus for copying
DE1271547B (de) * 1960-04-19 1968-06-27 Rank Xerox Ltd Of Mortimer Hou Verfahren zur UEbertragung eines Tonerbildes
DE2010156A1 (de) * 1969-03-10 1970-09-17 Xerox Corp., Rochester, N.Y, (V.St.A.) Einrichtung zur übertragung elektroskopischer Entwicklerteilchen
DE2138254A1 (de) * 1970-07-31 1972-03-09 Rank Xerox Ltd Elektrofotografische Entwicklungsvorrichtung
US3776723A (en) * 1972-08-09 1973-12-04 Xerox Corp Improved liquid transfer electrophotographic development process

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3405682A (en) * 1964-06-08 1968-10-15 Xerox Corp Xerographic development apparatus with web loading means to remove residual developer
US3663219A (en) * 1967-05-23 1972-05-16 Canon Camera Co Electrophotographic process
US3741760A (en) * 1968-02-23 1973-06-26 Xerox Corp Imaging system
US3687708A (en) * 1969-05-21 1972-08-29 Scm Corp Liquid development of latent electrostatic images
JPS5119337B1 (fr) * 1970-07-21 1976-06-16
US4021586A (en) * 1970-10-08 1977-05-03 Canon Kabushiki Kaisha Method of and means for the development of electrostatic images
AU473306B2 (en) * 1970-10-08 1976-06-17 Research Laboratories Of Australia Pty Ltd Method of and means for the developmetn of electrostatic images
US3952700A (en) * 1970-11-09 1976-04-27 Xerox Corporation Liquid applicator
US3783826A (en) * 1971-08-20 1974-01-08 Xerox Corp Ion film regulating device
DE2332253A1 (de) * 1973-06-25 1975-01-23 Siemens Ag Fluessigkristallspeicherbildschirm
US3998185A (en) * 1975-02-03 1976-12-21 Xerox Corporation Microfield donors with toner agitation and the methods for their manufacture
DE2507221C3 (de) * 1975-02-20 1981-03-26 Hoechst Ag, 65929 Frankfurt Vorrichtung zum Entwickeln eines latenten elektrostatischen Bildes auf einem elektrofotografischen Kopiermaterial

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD92858A (fr) *
US2784694A (en) * 1955-02-08 1957-03-12 Haloid Co Segmented development electrode
DE1271547B (de) * 1960-04-19 1968-06-27 Rank Xerox Ltd Of Mortimer Hou Verfahren zur UEbertragung eines Tonerbildes
US3232190A (en) * 1963-06-28 1966-02-01 Ibm Method and apparatus for copying
DE2010156A1 (de) * 1969-03-10 1970-09-17 Xerox Corp., Rochester, N.Y, (V.St.A.) Einrichtung zur übertragung elektroskopischer Entwicklerteilchen
DE2138254A1 (de) * 1970-07-31 1972-03-09 Rank Xerox Ltd Elektrofotografische Entwicklungsvorrichtung
US3776723A (en) * 1972-08-09 1973-12-04 Xerox Corp Improved liquid transfer electrophotographic development process

Also Published As

Publication number Publication date
DE3329451A1 (de) 1985-03-07
DE3471379D1 (en) 1988-06-23
AU567364B2 (en) 1987-11-19
CA1220334A (fr) 1987-04-14
US4587192A (en) 1986-05-06
EP0137188B1 (fr) 1988-05-18
AU3187284A (en) 1985-02-21
JPH045389B2 (fr) 1992-01-31
JPS6057875A (ja) 1985-04-03

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