EP0988579A1 - Vorrichtung und verfahren zum einfärben eines ladungsbildes über eine tonersprüheinrichtung - Google Patents
Vorrichtung und verfahren zum einfärben eines ladungsbildes über eine tonersprüheinrichtungInfo
- Publication number
- EP0988579A1 EP0988579A1 EP98928271A EP98928271A EP0988579A1 EP 0988579 A1 EP0988579 A1 EP 0988579A1 EP 98928271 A EP98928271 A EP 98928271A EP 98928271 A EP98928271 A EP 98928271A EP 0988579 A1 EP0988579 A1 EP 0988579A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- toner
- charge
- receiving surface
- area
- toner particles
- 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
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
- G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
- G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
Definitions
- the invention relates to a device and a method for coloring a charge image via a toner spraying device for electrographic printing or copying devices with high image carrier speed.
- developer systems For developing electrostatic charge images in printing devices with high image carrier speed, i.e. With an image carrier speed of 1 m per second and higher, developer systems are known which work with the aid of two-component magnet brush systems, with conductive one-component magnetic toner systems, with insulating non-magnetic single-component toner out of a toner air flow and with liquid development systems.
- the known two-component magnetic brush systems work with a mixture of toner particles and ferromagnetic carrier particles, which charge each other triboelectrically.
- the soft magnetic carrier particles form a brush in a magnetic field, which is in direct contact with the charge pattern - e.g. B. on a photoconductor - is brought.
- the charged toner particles are deposited on the surface of the charge-bearing element in accordance with the distribution of the electric field and the toner charge out of the magnetic brush.
- the toner particles In order to achieve high quality image development, the toner particles must be charged very homogeneously and the partially conductive brush must not discharge the photoconductor in contact. These conditions are very difficult to meet, particularly at high development speeds and high toner throughput.
- Conductive one-component magnetic brush systems work without a carrier material.
- the toner particles themselves contain a ferro-magnetic component. In the magnetic field, the toner particles form a brush structure, at the ends of which there are charged toner particles. Charging the
- Toner particles are made by transporting charge from the carrier roller from one toner particle to another.
- the disadvantage of this development method is that the ferromagnetic material component significantly limits the color rendering suitability of these toners.
- Optical density is often limited by the fact that, because of the conductivity of the particle brush, only the last particle is deposited and particles that are too weakly charged are picked up again. Furthermore, the conductivity of the toner particles leads to restrictions during the transfer from the photoconductor to the final image carrier to a further intermediate carrier - in particular when electrostatic toner transfer.
- toner When developing with insulating non-magnetic one-component toner from a toner air fluid as is known from EP 04 94 454B1, toner is fluidized in a homogeneous air flow and charged in this fluid by a corona discharge.
- the charged toner is deposited on a conductive roller, on which it adheres by electrostatic forces. From the roller surface, the toner can jump onto a surface with a charge image corresponding to the local electrical field distribution on this surface and thus develop an image-like toner image.
- One or more additional rollers can be inserted between the above-mentioned roller and the surface bearing the charge image in order to ensure that the toner particles have the correct charge polarity and the sufficient charge amount of the fewer or separate toner particles charged with the wrong polarity.
- fine toner particles are dispersed in a carrier liquid in which they become electrostatically charged with respect to the particle environment in the liquid.
- the developer liquid is usually brought into contact with the surface of the charge-bearing element (e.g. photoconductor).
- the charged toner particles migrate in the direction determined by the electric field and the toner charge.
- the "wet" toner image is then transferred to the final image carrier (usually paper).
- the remaining liquid escapes from the toner image (final image carrier) into the ambient air. This is a significant disadvantage when the liquid is an organic solvent, like the other isopare used as the carrier liquid.
- Liquid toner systems are also known in which a highly concentrated solution of highly charged particles jumps under the action of an electric field from an application roller surface onto those surface areas of the charge-image-carrying element into which the electrostatic force vector points, which is formed from the field vector and the toner charge in the liquid. So far, these systems have also had the disadvantage that organic solvents are used as carrier liquids.
- a device for developing a latent electrostatic image on a recording medium is also known from US Pat. No. 4,481,903.
- the device contains two brushes with deflectable bristles which serve as a charging device for the toner and which mechanically fling the charged toner particles against a developer roller in such a way that they spin forms a toner layer on the peripheral surface thereof.
- the toner adhering to the developer roller is then transported into the area of a developer nip, where it stains the latent charge image on the recording medium after the developer nip has been overcome.
- the z. B. a roller can produce a uniform, homogeneous toner layer. This toner layer is then transferred, depending on the charge image, to a carrier medium which is guided past at a close distance, namely by the individual toner particles jumping over the developer gap and thus coloring the charge image on the carrier medium.
- toner spray devices can be used, as are known from powder coating systems.
- powder coating guns are described, for example, in US Pat. No. 5,482,214 and US Pat. No. 4,802,625. The subject matter of these publications is part of the disclosure of this application.
- Figure 1 is a schematic sectional view of a developing device with a toner spraying device.
- Figure 2 is a schematic sectional view of the mouth of the toner spraying device with charging device.
- Figure 3 is a schematic sectional view of the developing device with associated deflection device.
- Figure 4 is a schematic representation of a toner spray device with a wide spray area.
- FIG. 5 shows a schematic illustration of a toner spraying device which can be moved along an application element
- Figure 6 is a schematic representation of a toner spraying device with a plurality of spray nozzles arranged side by side.
- An electrophotographic high-performance printing system not shown here in detail with a printing performance of more than 200 pages / min. comprises one or more of the developing devices shown in FIG. 1. These development devices are used to color a latent charge image on a carrier medium 10 with the aid of a character generator.
- the carrier medium 10 can be a photoconductor drum, ie a metallic body with a photoconductive surface, for example made of As 2 SE 3 or - as shown here - an OPC photoconductor tape.
- the photoconductor or the carrier medium 10 is first charged to - 500 V and then discharged to -50 V using the character generator.
- the carrier medium 10 is at approximately ⁇ 500 V, in the region of the toner image at ⁇ 50 V. It is also possible, however, to charge the carrier medium first to + 500 V and then to depending on the character + 50 V to discharge.
- the toner image is colored with the aid of the developer device shown, using one-component toner or else two-component toner which contains toner particles of approximately 10 ⁇ m in size on any resin basis, such as e.g. Has polysthrol or polyester and, in the case of two-component toners, electromagnetic carrier particles.
- the toner particles are deposited on the photoconductor depending on the charge image. After the development process they are transferred to paper in a transfer printing station in the usual way and then e.g. fixed in a thermal pressure fixing device.
- the developing device contains a toner spraying device 11, which can be constructed analogously to a powder coating device.
- powder coating devices are known for example from US 5482214 and US 4802625. They generally consist of a feed pipe 12 with a nozzle 13 shown in FIG. 2, which has an electrode 14 in the form of a corona charging device in its mouth region.
- a mixture flow is generated from a toner-air mixture, which has toner particles with a defined toner charge.
- toner is dispersed in air and this mixture flow is passed through the Feed pipe 12 supplied to the nozzle 13 and thus generates a directed spray.
- the electrode 14 is subjected to a voltage of +5 or -5 KV or greater and sprays charges onto the toner particles, which then have a toner charge of preferably ⁇ 10 ⁇ C / g to ⁇ 30 ⁇ C / g.
- the electrode acting as a corona discharge device can be arranged in the mixture stream or in the immediate vicinity of the mixture stream 15. It charges the toner particles in a defined manner.
- the toner application efficiency is defined as the ratio of the mass flow (toner) transported in the air flow to the mass flow (toner) deposited on the receiving surface (application element 16).
- An application element 16 is arranged in the area of the mixture stream 15.
- it consists of a metal roller with a partially conductive surface, for example of amorphous carbon, so that the distance between the toner charge and its mirror charge is large enough to enable the toner to adhere to the application element 16 and small enough so that the required detachment field does not become too large , because the photoconductor charge is limited.
- a roller-shaped application element 16 it is also possible to use an endless belt.
- the application element 16 is moved by a motor in the direction of the arrow.
- a corona device 17 is arranged on the application element 16 and serves to apply an ion current to a toner layer applied to the application element 16 with the aid of the toner spray device 11 and thus to even out the charge in the toner layer.
- the surface of the application element 16 is located at a close distance from the carrier medium 10, specifically at a distance that can be less than 100 ⁇ m, the gap defining the actual developer area or transfer area 18.
- the carrier medium 10 in this case the photoconductor belt, is guided by a spacer roller 19 in this area.
- a wiping element 20 made of elastic material, which serves to wipe off residual toner from the application element 16 and to feed it to a toner reservoir via a conveying device 21.
- a further corona device 23 is arranged in front of the stripping element 20.
- a mixture stream 15 in the form of a spray jet of charged toner particles is generated in a transport air stream with the aid of the toner spraying device 11.
- the application element 16 is at an application potential of ⁇ 450 V. Due to these voltage conditions in connection with the toner charge, the toner particles accumulate in a receiving area 22 on the surface of the application element 16. The attachment of the toner particles is supported by their kinetics (momentum). The kinetics in turn depend on the speed of the transport air flow carrying the toner particles. The momentum of the toner particles increases the Toner application efficiency TAW. There they form a uniform, homogeneous layer with a layer thickness of approximately 1-3 toner layers or more.
- an ion current is applied to this layer in order to even out the charge in the layer.
- the receiving area 22 with the toner layer reaches the transfer area 18 with the developer gap, where the toner particles, depending on the charge image, jump from the application element 16 via the developer gap of about 100 ⁇ m width or less onto the charge image of the carrier medium 10 and color it.
- an auxiliary transmission voltage of preferably 200-500 V can be present between the carrier medium 10 and the application element 16 in the transmission area 18. It is switched on during the entire development period.
- the toner particles accumulate on the charge image of the carrier medium 10 if a suitable toner charge is present, if the charge of the carrier medium 10 is selected correctly and the so-called V jump potential "and the mechanical distance in the developer gap 18 is selected correctly
- the toner charge is between 10 and 30 ⁇ C / g with a potential of the application element of -450 V.
- the auxiliary transmission voltage is preferably 200-500 V.
- the toner-free areas are at -500 V, the latent charge image to about - 50 V.
- the field force acting on the toner particles in the developer area is about 8 x 10 "8 N.
- the toner particles accumulate in the discharged photoconductor area (- 50 V), preferably in 1-2 toner layers depending on the charge.
- a switchable deflection device can be provided as shown in FIG. 3. This essentially consists of a switchable electrical deflection field 26 between a collecting area 24 and a deflection electrode 25, the pole direction of the field 26 being shown symbolically.
- the toner spraying device is oriented such that, in the absence of the additional electrical field 26, the center of the jet passes the application element 16 at a distance from it and strikes the receiving area 22.
- the toner particles with the correct charge polarity (negative particles) and a sufficiently large amount of charge (10-30 ⁇ C / g) are deflected in a curved path 27 towards the application element 16. Particles with an insufficient charge amount and other charge polarity fly past the application element (16) and hit the application in the region of the rays 28.
- Hl tr SU do £ ⁇ ⁇ ⁇ CU: ⁇ cn p- ⁇ d tr ⁇ C ⁇ rt ⁇ d ⁇ y Q Pl: P dodd P ⁇ SU ⁇ cu et P 1 et a P 4-> P ⁇ P SU SU tr Pi ⁇ rt tr d • 3 e P- co ⁇ P ⁇ to dd
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Dry Development In Electrophotography (AREA)
- Wet Developing In Electrophotography (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19724950 | 1997-06-12 | ||
DE19724950 | 1997-06-12 | ||
PCT/EP1998/002870 WO1998057233A1 (de) | 1997-06-12 | 1998-05-15 | Vorrichtung und verfahren zum einfärben eines ladungsbildes über eine tonersprüheinrichtung |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0988579A1 true EP0988579A1 (de) | 2000-03-29 |
EP0988579B1 EP0988579B1 (de) | 2003-02-19 |
Family
ID=7832332
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP98928271A Expired - Lifetime EP0988579B1 (de) | 1997-06-12 | 1998-05-15 | Vorrichtung und verfahren zum einfärben eines ladungsbildes über eine tonersprüheinrichtung |
Country Status (4)
Country | Link |
---|---|
US (1) | US6377768B1 (de) |
EP (1) | EP0988579B1 (de) |
DE (1) | DE59807252D1 (de) |
WO (1) | WO1998057233A1 (de) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19857257B4 (de) * | 1998-12-11 | 2006-12-07 | OCé PRINTING SYSTEMS GMBH | Entwicklungsvorrichtung mit Tonersprüheinrichtung, deren Gemischstrom auf einen Auftragsbereich schräg auftrifft |
DE19940037B4 (de) | 1999-08-24 | 2006-10-05 | OCé PRINTING SYSTEMS GMBH | Elektrografische Druckeinrichtung mit zusätzlichem Farbdruckwerk sowie Verfahren hierzu |
US20040184840A1 (en) * | 2003-03-21 | 2004-09-23 | Xerox Corporation | Ion toner charging device |
US7149460B2 (en) * | 2005-03-16 | 2006-12-12 | Xerox Corporation | Systems and methods for electron charging particles |
US7502580B2 (en) * | 2005-11-30 | 2009-03-10 | Xerox Corporation | Two component development system using ion or electron charged toner |
Family Cites Families (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5137540B1 (de) | 1965-11-19 | 1976-10-16 | ||
US4100884A (en) | 1976-02-25 | 1978-07-18 | Ricoh Company, Ltd. | Rubber developer roller using single component toner |
DE3205989A1 (de) | 1982-02-19 | 1983-09-01 | Hoechst Ag, 6230 Frankfurt | Verfahren und vorrichtung zum entwickeln eines auf einem aufzeichnungstraeger erzeugten elektrostatischen latenten bildes |
JPS614071A (ja) | 1984-06-18 | 1986-01-09 | Olympus Optical Co Ltd | 現像方法および現像装置 |
JPS61151675A (ja) | 1984-12-26 | 1986-07-10 | Sharp Corp | トナ−搬送装置 |
DE3608415A1 (de) | 1986-03-13 | 1987-09-24 | Gema Ransburg Ag | Elektrostatische sprueheinrichtung fuer beschichtungspulver |
US5557376A (en) | 1989-05-15 | 1996-09-17 | Indigo N.V. | Color imaging system |
JP2856820B2 (ja) | 1990-02-28 | 1999-02-10 | 株式会社リコー | 現像装置 |
JPH041782A (ja) | 1990-04-19 | 1992-01-07 | Fujitsu Ltd | トナー選別装置 |
US5532100A (en) | 1991-01-09 | 1996-07-02 | Moore Business Forms, Inc. | Multi-roller electrostatic toning |
DE4141663C2 (de) | 1991-12-17 | 1996-09-19 | Wagner Int | Elektrostatische Pulver-Beschichtungspistole |
US5477285A (en) | 1993-10-06 | 1995-12-19 | Thomson Consumer Electronics, Inc. | CRT developing apparatus |
KR0184123B1 (ko) * | 1996-04-03 | 1999-03-20 | 손욱 | 음극선관 패널의 현상장치 |
DE19857257B4 (de) * | 1998-12-11 | 2006-12-07 | OCé PRINTING SYSTEMS GMBH | Entwicklungsvorrichtung mit Tonersprüheinrichtung, deren Gemischstrom auf einen Auftragsbereich schräg auftrifft |
-
1996
- 1996-05-15 US US09/445,708 patent/US6377768B1/en not_active Expired - Fee Related
-
1998
- 1998-05-15 EP EP98928271A patent/EP0988579B1/de not_active Expired - Lifetime
- 1998-05-15 DE DE59807252T patent/DE59807252D1/de not_active Expired - Fee Related
- 1998-05-15 WO PCT/EP1998/002870 patent/WO1998057233A1/de active IP Right Grant
Non-Patent Citations (1)
Title |
---|
See references of WO9857233A1 * |
Also Published As
Publication number | Publication date |
---|---|
US6377768B1 (en) | 2002-04-23 |
EP0988579B1 (de) | 2003-02-19 |
WO1998057233A1 (de) | 1998-12-17 |
DE59807252D1 (de) | 2003-03-27 |
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