EP1649326B1 - Device and method for electrophoretic liquid development - Google Patents

Abstract

Disclosed is a developing station (E) comprising a developing roller (203), a screen roller (202), and an optional chambered doctor blade (201). Said developing station develops charge patterns that are applied to an image-supporting element (F), e.g. a photoconductor drum, by means of liquid developer. Such a construction of the developing station makes it possible to provide a plurality of structurally identical printing units along one recording medium while the printing unit can be operated at a variable printing speed.

Description

For single or multi-color printing of a recording medium, e.g. a single sheet or a tape-shaped recording medium made of various materials, e.g. Paper or thin plastic or metal foils, it is known, on a potential image carrier, e.g. a photoconductor, image-dependent to generate potential images (charge images), which correspond to the images to be printed, consisting of areas to be inked and non-inked. The areas to be inked (hereinafter referred to as image sites) of the potential images are made visible by toner with a developer station (inking station). Subsequently, the toner image on the recording medium (also called substrate or Endbildträger called) umgedruckt.

For dyeing the image areas, either dry toner or toner-containing liquid developer can be used.

A process for electrophoretic liquid development (electrographic development) in digital printing systems is, for example EP 0 756 213 B1 or EP 0 727 720 B1 known. The method described there is also known by the name HVT (High Viscosity Technology). In this case, a liquid containing silicone oil carrier fluid having dispersed therein color particles (toner particles) is used as a liquid developer. The toner particles typically have a particle size of less than 1 micron. More about this is from the EP 0 756 213 B1 or EP 0 727 720 B1 removable, which are part of the disclosure of the present application. There are described electrophoretic liquid development process of the type mentioned with silicone oil as a carrier liquid with toner particles dispersed therein and also a developer station of one or more developer rollers for wetting the image bearing member with liquid developer according to Potential images on the image carrier element. The developed potential image is then transferred to the recording medium via one or more transfer rollers.

Further prior art is out WO 01/92968 . EP 1090756 and US 4411514 known.

The problem to be solved by the invention is to provide an electrographic printing apparatus and a method with which a variable printing speed can be realized with a constant print quality.

This problem is solved with a printing device according to the features of claim 1 and with a method with the features of claim 12.

The printing device has the advantage that a change in the printing speed is infinitely and in a wide range without reducing the print quality is possible.

According to the invention, there is provided a printing apparatus consisting of an image-forming system which generates an electronic charge image on an image-bearing member (e.g., photoconductor) which is visualized by charged toner particles (toner particles) by means of a developer station and then onto a record carrier or final image carrier (e.g. B. paper) and fixed on this.

• die Geschwindigkeit des Bildträgerelementes kontinuierlich von 0 bis zur Grenzgeschwindigkeit durchzuvariieren;
• die elektronische Zeichengenerierung und ggf. die Aufladeintensität der Geschwindigkeit des Bildträgerelementes anzupassen (hinsichtlich Informationsort und Energie pro Fläche), so dass z. B. beim elektrografischen Prozess das Ladungsbild bzgl. Form und Potentialwerten unabhängig von der Geschwindigkeit des Bildträgerelementes immer in gleicher Weise entsteht;
• die Entwicklung des Ladungsbildes mit einem Verfahren durchzuführen, das es erlaubt, die Signalverteilung auf dem Bildträgerelement unabhängig von dessen Geschwindigkeit zu entwickeln (beim elektrografischen Prozess bedeutet dies, dass während des Entwicklungsprozesses gleiche Potentialverteilungen auf dem Bildträgerelement immer die gleichen Tonerverteilungen auf dem Ladungsbild erzeugen).

In such a printing device, it is possible

• continuously varying the speed of the image bearing member from 0 to the limit speed;
• adapt the electronic character generation and possibly the charging intensity of the speed of the image carrier element (with respect to information location and energy per area), so that z. B. in the electrographic process, the charge image with respect. Form and potential values regardless of the speed of the image carrier element always arises in the same way;
• to perform the development of the charge image with a method that allows the signal distribution to the image carrier element regardless of its speed to develop (in the electrographic process, this means that during the development process equal potential distributions on the image carrier element always produce the same toner distributions on the charge image).

In the event that the development of the charge image is not completely independent of the speed of the image carrier element, the process parameters (eg photoconductor potential, light energy, auxiliary potential above the developer gap, toner concentration, or auxiliary potentials for transfer to the final image carrier) can be varied in this way in that the toner image deposit on the image carrier element or the final image carrier becomes almost identical at different speeds. The parameters to be influenced are preferably to be coupled to one another via one or more control processes.

Preferably, a development process is used which inherently produces a toner deposit independent of the limit speed of the image-bearing member. This happens z. For example, by a liquid development in which in a high-resistance carrier liquid (eg., Silicone oil) fine toner particles (preferably about 1 micron diameter or smaller) are dispersed, wherein the concentration of the toner particles is so highly selectable that in a thin developer gap (Preferably 5 to 10 microns) between the image bearing member and a developer roller so many toner particles are that with complete (or almost complete) deposition of all the toner particles located in the developer gap the desired coloration (optical density or color density) is formed on the image bearing member. The prerequisite for the function is further that the mobility of the toner particles in the development gap is at least so large that during the residence time of the toner particles in the developer gap all (or almost all) toner particles under the influence of over the inked areas of the image bearing element existing electric field strength to completely pass through the developer gap and be deposited on the areas to be inked on the surface of the image carrier element and not or almost not deposited on the surface of the image carrier under the influence of over the non-inking areas of the image carrier existing electric field strength.

In this method, in conjunction with a targeted adjustment of the toner concentration in the developer liquid, the achievable maximum coloration can be preselected or adjusted. Thus, in this printing process, a certain set maximum inking can be kept constant at variable printing speed.

Such a developer station may comprise a developer roller which transports a liquid developer past the image carrier member such that the toner deposit on the image carrier member is independent of its speed.

• dass benachbart dem Bildträgerelement eine Entwicklerwalze vorgesehen ist, die den Tonerteilchen aufweisenden Flüssigentwickler an dem Bildträgerelement vorbeiführt und von dem Tonerteilchen zum Bildträgerelement entsprechend den zuvor erzeugten Ladungsbilder übergehen,
• dass benachbart der Entwicklerwalze eine Rasterwalze angeordnet ist, in dessen Rasterung der Flüssigentwickler zur Entwicklerwalze transportiert wird,
• dass benachbart zur Rasterwalze eine eine Dosierrakel aufweisende Kammerrakel angeordnet ist, von der die Rasterwalze über die Dosierrakel den Flüssigentwickler übernimmt, deren Lage zur Rasterwalze einstellbar ist und die derart ausgebildet ist, dass die Dosierrakel von Flüssigentwickler überflutet ist.

The developer station can be designed in such a way

• in that a developer roller is provided adjacent to the image carrier element, which passes the toner developer having the toner particles past the image carrier element and passes from the toner particle to the image carrier element in accordance with the previously generated charge images,
• that an anilox roller is arranged adjacent to the developer roller, in the screening of which the liquid developer is transported to the developer roller,
• in that adjacent to the anilox roller there is arranged a doctor blade having a metering doctor, from which the anilox roller takes over the liquid developer via the metering doctor whose position relative to the anilox roller is adjustable and which is designed such that the metering doctor is flooded by liquid developer.

The flooding can be achieved due to the liquid developer's gravity or by using overpressure.

It is advantageous that the amount of liquid developer conveyed by the anilox roller can be determined by the screening of the anilox roller. In this case, the promotion of the liquid developer by the anilox roll is area-related and thus independent of the printing speed, so that at different printing speeds always the same amount of liquid developer per unit area is brought to the developer roller.

It is advantageous if the anilox roller has a screening, which allows the promotion of a volume of liquid developer from 1 to 40 cm ³ / m ² (based on the roll surface), preferably 5-20 cm ³ / m ² .

It is furthermore advantageous if the developer roller has an elastic coating which is in contact with the image carrier element and with the anilox roller.

The chambered doctor blade may be a seated on the peripheral surface of the anilox roller chamber, with two sealing the chamber squeegees, namely seen a closing squeegee at the entrance of the chamber in the direction of rotation of the anilox roller, and a metering blade at the exit of the chamber in the direction of rotation of the anilox roller, and with two the edge of the anilox adjacent lateral seals. In this case, the supply of the liquid developer into the chamber through one or more inlet openings, preferably via pumps, and the removal of the liquid developer from the chamber through inlet or outlet openings.

With this printer device, the supply of the liquid developer to the image-bearing member can be simplified.

• der flexible Einsatz und / oder Anordnung einer Kammerrakel innerhalb der Vorrichtung (Entwicklerstation);
• die Vorrichtung ist geeignet zur Anwendung im Bereich (digitaler) elektrostatischer (elektrophoretischer) Druckverfahren;
• die kompakte Bauweise der Vorrichtung z.B. als wesentlicher Bestandteil eines kompakten Druckwerkes;
• eine Vorrichtung, die bei variablen Einbaupositionen in einer Druckeinrichtung identisch ist, und damit variable Druckerkonfigurationen ermöglicht.

Advantages of this are:

• the flexible use and / or arrangement of a chambered doctor blade within the device (developer station);
• the device is suitable for use in the field of (digital) electrostatic (electrophoretic) printing processes;
• the compact design of the device, for example as an integral part of a compact printing unit;
• a device which is identical in variable mounting positions in a printing device, and thus enables variable printer configurations.

In order to ensure a bubble-free transport of the liquid developer, it is expedient to arrange the chambered doctor blade to the grid means that the metering blade is flooded by liquid developer. The same result can be achieved if the liquid developer in the chambered doctor blade is exposed to overpressure, so that the metering doctor blade is flooded by liquid developer.

In order to remove the inverse residual image having liquid developer from the developer, a cleaning device can be arranged adjacent to the developer, which takes over the residual image. The cleaning device may comprise a cleaning roller and a cleaning element, e.g. a squeegee that strips the liquid developer from the cleaning roller.

The developing agent may be a developer tape, preferably a developer roller. The screen means is preferably an anilox roller, but may also be a screen tape.

The amount of liquid developer transported to the developer roller can be influenced in a simple manner by the screening of the anilox roller. It is advantageous if the anilox roller has a screening which allows the conveyance of a volume of liquid developer from 1 to 40 cm ³ / m ² (based on the roller surface), preferably 5-20 cm ³ / m ² . In this case, the promotion of the liquid developer by the anilox roll is area-related and thus independent of the printing speed, so that at different printing speeds always the same amount of liquid developer per unit area is brought to the developer roller.

It is advantageous that the developer roller, screen roller and cleaning roller can rotate at constant speed ratios (surface speeds), preferably in the ratio 1: 1: 1. In this case, the directions of movement of the surfaces of the developer roller and image carrier element can be the same direction or opposite, the developer roller and anilox roller rotate in the same direction or in opposite directions, the developer roller and cleaning roller in the same direction or in opposite directions.

In order to favorably influence the transition of liquid developers, a potential for specific field effect on the charged toner particles can be applied to the developer roller and the image carrier element. This also applies between developer roller and cleaning roller as well as between anilox roller and developer roller.

In order to further favorably influence the transition of liquid developers, it is expedient to provide the developer roller with an elastic coating in order to create defined zones of action to the adjacent elements. The effective zone then arises through a defined deformation of the elastic coating of the developer roller, preferably via spring force delivery to the adjacent elements (image carrier element, cleaning roller, anilox roller). An effective zone is also created by the incompressible layer of the liquid developer, which defines the distance between the developer roller and the image carrier element, developer roller and cleaning roller and developer roller and anilox roller.

The chambered doctor blade may comprise a chamber sitting on the peripheral surface of the anilox roller, two doctoring blades sealing the chamber, a squeegee seen at the entrance of the chamber in the direction of rotation of the anilox roller, seen a metering blade at the exit of the chamber in the direction of rotation of the anilox roller, and two adjacent to the lateral edge of the anilox roller have lateral seals. The supply of the liquid developer in the chamber can be done through one or more inlet openings preferably via pumps; the removal of the liquid developer from the chamber through inlet or discharge openings, wherein the inlet or discharge openings should be exchangeable depending on the installation position to the anilox roller.

To avoid the inclusion of air bubbles in unfavorable mounting position, e.g. the metering blade is above the squeegee in the direction of gravity, and to handle higher viscosity liquid developers (e.g., 1000 mPa * s) a slight overpressure can be created in the chamber.

It is advantageous that the installation position of the chambered doctor blade on the anilox roller is made variable. Likewise, the installation position of the cleaning device can be made variable on the developer roller.

Particularly advantageous is the use of the device as a developer station in an electrophoretic printing device. It is then particularly advantageous that in the developer station, the developer roller, the anilox roller and the cleaning roller can be arranged at a constant angle to each other, so that the arrangement of developer stations to a roller-shaped image carrier element under different angular positions is possible without the assignment of developer roller, anilox roller To change cleaning roller to each other, ie developer stations of the same structure can be arranged without change at different positions along the image carrier element. This advantage is further increased by the fact that the angular position of the chambered doctor blade on the anilox roller can be changed.

Thus, printing modules can be created, each having a developer station and an image bearing member, which can be arranged along a deflected recording medium under different angular positions, the arrangement of chamber doctor blade, anilox roller and developer roller is maintained to each other in the developer station. The printing module may additionally comprise a transfer roller, e.g. transfers the toner images from the image bearing member to the recording medium.

• Die Geschwindigkeit der Entwicklung ist flexibel anpassbar je nach Einsatzzweck, Anfahren, Stoppen durch Zufuhr des Flüssigentwicklers über die Rasterwalze.
• Der einfache Aufbau (z.B. nur drei Walzen) ermöglicht eine kompakte Bauform und damit kompakte Druckwerksgestaltungen.
• Das Dosierverhalten einer Kammerrakel ist im großen Bereich weitgehend viskositätsunabhängig (0,5 - 1000 mPa*s) und bewirkt damit:
  • eine stabile Verarbeitung unterschiedlicher Konzentrationen des Flüssigentwicklers und damit hohe Prozessstabilität;
  • die Nutzung gleich aufgebauter Entwicklerstationen für unterschiedlichen Flüssigentwickler (z.B. für unterschiedliche Applikationen).

Advantages of this are:

• The speed of development is flexibly adaptable depending on the application, starting, stopping by feeding the liquid developer over the anilox roller.
• The simple design (eg only three rollers) enables a compact design and thus compact printing unit designs.
• The metering behavior of a chambered doctor blade is largely independent of viscosity (0.5-1000 mPa * s) in the large range and thus causes:
  • a stable processing of different concentrations of the liquid developer and thus high process stability;
  • The use of identical development stations for different liquid developers (eg for different applications).

The printing device for printing on a printing substrate can consist of a combination of one or more printing units with a common printing material guide mechanism and with a central control unit for coordinating the processes in the printing units, in the printing material guide as well as in possibly connected devices of the printing material pre- or post-processing.

The combination of substantially identical (cross-sectional arrangement equal, depth corresponding to the processed Substrate width), compact and easy-to-handle printing modules for a printing device with different substrate guides, both for "Continuous Feet" and for "cut sheet" (sheetfed or sheetfed printing) enables the flexible design of various printing devices: from B / W (Black and White) - Simplex to B / W Duplex, YMCK (Yellow, Magenta, Cyan, Black) - Full Color Simplex to Complex Full Color Duplex Printers with four or more printing units on each Bedruckstoffseite. In addition to the uncomplicated structure of the complex printing devices at the manufacturer, the comparatively easy conversion and upgradability existing. Printing devices at the customer advantageous. The use of identical modules, especially in the printing units, also allows cost-effective production by large numbers.

• Großer Geschwindigkeitsbereich (z.B. 0,3 bis 3 m/s);
• Bedruckstoffbreite vorteilhafterweise bis mindestens 22 Zoll, schmaler ist aber möglich;
• Durchstimmbare Geschwindigkeit während des laufenden Druckbetriebs im gesamten Geschwindigkeitsbereich;
• Kompakte Bauform der Druckwerke (z.B. (50x100)cm² Querschnitt, Tiefe entsprechend Hedruckstoffbreite);
• Leichte Handhabbarkeit der Druckwerke beim Ein- und Ausbau in bestehende Druckvorrichtungen (Um- bzw. Aufrüstung), ggf. durch geeignete Hilfsdruckvorrichtungen.

Advantageous properties of the printing units and printing material works are:

• High speed range (eg 0.3 to 3 m / s);
• Substrate width advantageously up to at least 22 inches, but narrower is possible;
• Tunable speed during the current printing operation in the entire speed range;
• Compact design of the printing units (eg (50x100) cm ² cross-section, depth corresponding to the substrate width);
• Easy handling of the printing units during installation and removal in existing printing devices (conversion or upgrade), possibly by suitable auxiliary pressure devices.

In the following the various aspects of the invention will be described with reference to the figures, which represent the invention alone and in combination.

Fig. 1

eine Darstellung der Entwicklerstation bei einer ers- ten Position zum Bildträgerelement;

Fig. 2

eine Darstellung der Entwicklerstation bei einer zwei- ten Position zum Bildträgerelement;

Fig. 3

eine Darstellung der Entwicklerstation bei einer drit- ten Position zum Bildträgerelement;

Fig. 4

eine Darstellung der Entwicklerstation bei unter- schiedlicher Anordnung der Kammerrakel zur Rasterwal- ze;

Fig. 5

eine Darstellung von Druckmodulen mit Entwicklerstati- onen um einen Aufzeichnungsträger;

Fig. 6

ein einzelnes Druckwerk, das als Modul zu einer Druck- vorrichtung zusammen gesetzt werden kann;

Fig. 7

eine Druckvorrichtung zum Bedrucken von Endlos- Be- druckstoffbahnen;

Fig. 8

eine Druckvorrichtung zum Bedrucken von Einzelblättern (cut sheet).

Show it:

Fig. 1

a representation of the developer station at a first position to the image carrier element;

Fig. 2

a representation of the developer station at a second position to the image carrier element;

Fig. 3

a representation of the developer station at a third position to the image carrier element;

Fig. 4

a representation of the developer station with different arrangement of the chamber doctor blade to the anilox roller;

Fig. 5

a representation of printing modules with developer stations to a recording medium;

Fig. 6

a single printing unit, which can be put together as a module to form a printing device;

Fig. 7

a printing device for printing endless printing material webs;

Fig. 8

a printing device for printing on single sheets (cut sheet).

Device for transporting liquid developer to an image-carrying element in electrophoretic digital printing

• Die Entwicklerstation E der Figur 1 weist auf:
  • Eine Entwicklerwalze 203 mit einer elastischen Beschichtung 206; selbstverständlich können auch mehrere Entwicklerstationen vorgesehen werden;
  • eine Rasterwalze 202 mit einer Rasterung aus darauf angeordneten Vertiefungen (Näpfchen), es können auch mehrere Rasterwalzen vorgesehen werden; die Rasterung kann je nach Anwendungsfall unterschiedlich ausgeführt sein;
  • eine in ihrer Position gegenüber der Rasterwalze veränderbare Kammerrakel 201;
  • eine Reinigungseinrichtung mit einer Reinigungswalze 204 und einem Reinigungselement 205.

Construction of a developer station E after FIG. 1 :

• The developer station E the FIG. 1 indicates:
  • A developer roller 203 having an elastic coating 206; Of course, several developer stations can be provided;
  • an anilox roller 202 with a grid of recesses arranged thereon (wells), it can also be provided a plurality of anilox rollers; the screening can be carried out differently depending on the application;
  • a in its position relative to the anilox roll variable chamber blade 201;
  • a cleaning device with a cleaning roller 204 and a cleaning element 205.

The developer roller 203 contacts an image-bearing member F, eg, a photoconductor of a photoconductor belt or a roller, with a photoconductor layer disposed thereon. Furthermore, a transfer roller 121, Fig. 5 for transferring the toner toner-colored toner image from the image-bearing member F to a tape-shaped recording medium 1 or a sheet-shaped recording medium.

It is possible to use a liquid developer suitable for electrophoretic development with colorant (toner particles) distributed therein, such as for example EP 0 756 213 B1 or EP 0 727 720 B1 is known.

The supply of the liquid developer for imagewise coloring of the image carrier member F with toner particles via the chambered doctor blade 201 and the anilox roller 202 to the developer roller 203. The cleaning of the inverse residual image of the developer roller 203 in turn takes place by its transfer to the cleaning roller 204 and removal of the liquid developer from the cleaning roller 204 by a cleaning element 205, eg a squeegee. From the purifier 204, 205, the removed liquid developer may be returned to a liquid developer supply reservoir (not shown).

The developer roller 203, anilox roller 202, and cleaning roller 204 advantageously rotate at constant speed ratios to one another (surface speeds), preferably at a ratio of 1: 1: 1. The direction of rotation of the developer roller 203 and the image-bearing member F may be the same or opposite, that of the developer roller 203 and the anilox roller 202 and the developer roller 203 and the cleaning roller 204 may be the same direction or opposite. Defined potentials for targeted field effect on the charged toner particles can be applied to them.

The developer roller 203 has an elastic coating 206 and is in contact with the image bearing member F, the screen roller 202, and the cleaning roller 204.

The anilox roller 202 is adapted in its screening to promote a volume of liquid developer from 1 to 40 cm ³ / m ² (based on the roll surface), preferably 5-20 cm ³ / m ² _.

The promotion of liquid developer is also area-related and thus independent of the printing speed, i. at different printing speeds, the same amount of liquid developer per unit area can always be supplied to the developer roller 203.

• durch definierte Verformung der elastischen Beschichtung 206 der Entwicklerwalze 203 vorzugsweise über Federkraft-Zustellung zu benachbarten Elementen, wie z.B. Bildträgerelement F, Rasterwalze 202 oder Reinigungswalze 204;
• durch die inkompressible Schicht des Flüssigentwicklers zwischen Entwicklerwalze 203 und Bildträgerelement F, Entwicklerwalze 203 und Reinigungswalze 204 oder Entwicklerwalze 203 und Rasterwalze 202.

The formation of defined action zones for the transition of liquid developer between developer roller 203 and image carrier element F, developer roller 203 and cleaning roller 204 and developer roller 203 and anilox roller 202 can be achieved in various ways:

• by defined deformation of the elastic coating 206 of the developer roller 203 preferably via spring force delivery to adjacent elements, such as image carrier element F, anilox roller 202 or cleaning roller 204;
• through the incompressible layer of the liquid developer between developer roller 203 and image carrier element F, developer roller 203 and cleaning roller 204 or developer roller 203 and anilox roller 202.

• Die Kammerrakel 201 ist für den Offsetdruck aus Kipphan, Handbuch der Printmedien, Springer Verlag, 2000, bekannt. Ihr Einsatz für den eletrophoretischen digitalen Druck bei unterschiedlichen Lagen der Entwicklerstation 200 zum Bildträgerelement F ergibt sich aus den Fig. 1 bis 4.

Construction and arrangement of the chambered doctor blade (201), in particular according to Fig. 4 :

• The chambered doctor blade 201 is known for offset printing from Kipphan, Handbuch der Printmedien, Springer Verlag, 2000. Their use for the electrophoretic digital printing at different positions of the developer station 200 to the image carrier element F results from the Fig. 1 to 4 ,

The chamber doctor blade 201 is a seated on the peripheral surface of the anilox roller 202 chamber 207 which is sealed by two doctor blades, the squeegee R1 seen at the entrance of the chamber 207 in the direction of rotation of the anilox roller 202, the metering blade R2 at the exit of the chamber 207 in the direction of rotation of the anilox roller 202nd seen, and two seals for sealing to the lateral edge of the anilox roller 202 (not visible in the figures). The supply of the liquid developer into the chamber 207 of the chambered doctor blade 201 can take place through one or more openings, preferably via pumps. The removal of the liquid developer from the chamber 207, for example, advantageously for better mixing of the liquid developer, and the emptying of the chamber 207 can be done either via inlet or outlet openings. In this case, an exchange of the inlet or outlet openings, depending on the installation position of the chambered doctor blade 201 (FIG. Fig. 2 . Fig. 3, Fig. 4 ) possible (in the Fig. 2 and 3 g denotes the direction of action of gravity and thus its influence on the liquid level in the chambered doctor blade 201).

The angular position of the chambered doctor blade 201 to the anilox roller 202 is limited by the fact that the metering doctor blade R2 always has to be located below the surface of the liquid developer (this is for free air filling of the cells of the screening of the anilox roller 202).

Optionally, the generation of a slight overpressure in the chambered blade 201 may be used to hold the metering blade R2 below the liquid surface. This solution is also suitable for processing higher viscosity liquid developers (e.g., 1000 mPa * s).

• eine Ausführungsform sieht konstante Winkel zwischen Entwicklerwalze 203, Reinigungswalze 204 und Rasterwalze 202 vor und ermöglicht eine Anordnung um das Bildträgerelement F herum in verschiedenen Winkeln;
• eine Erweiterung der Einbaulagen ergibt sich durch die zusätzliche Möglichkeit, die Winkellage der Kammerrakel 201 an der Rasterwalze 202 zu verändern, Fig. 4.

The mounting positions of the chambered doctor blade 201 to the anilox roller 202 are selectable, as the Fig. 4 shows. The screen roller 202 together with the chamber blade 201 can be arranged to the developer roller 203 depending on the installation position of the developer roller 203 so that the metering blade R2 is flooded with liquid developer, Fig. 1 to 4 , The following embodiments are advantageous:

• one embodiment provides constant angles between developer roller 203, cleaning roller 204 and anilox roller 202, and allows placement about the image bearing member F at various angles;
• an extension of the mounting positions results from the additional possibility of changing the angular position of the chambered doctor blade 201 on the anilox roller 202, Fig. 4 ,

Fig. 5 shows an arrangement of a plurality of printing modules (PM), for example in a digital color printing device. Here are print modules PM each with an image carrier element F, a developer station (in Fig. 5 designated E) and a transfer roller 121 which transfers the toner image from the image bearing member F to a recording medium 1 to the recording medium 1, which is deflected by a guide roller 2, arranged. The structure of the developer stations E accordingly Fig. 1 to 4 makes it possible to arrange structurally identical printing modules PM in the deflection region of the recording medium 1 at different angles. This is achieved, in particular, by the use of chamber doctor blades 201 for supplying the liquid developer to the image carrier element F, since this permits the use of identical developer stations E at various installation positions (simplex, duplex, horizontal, vertical, angular range> 120 ° for satellite arrangement); please refer Fig. 5 for a digital color printer with several developer stations E1-E5 according to the desired color separations. In this case, the angular range can be determined by additionally adjustable positions of the chambered doctor blade 201 (and the cleaning device 204, 205) via an adjustment device or by adjustable design of chambered doctor blade 201 and cleaning device 204, 205 (FIG. Fig. 2 . Fig. 3 ) to be changed.

Modular printed device

In the following, a printing system consists of a combination of a plurality of successively arranged printing units 100 with a common Bedruckstoffführungswerk 200. At the printing system machines can be connected to the pre-printing or post-processing. A central control unit 400 for coordinating the processes in the printing units 100 and in the Bedruckstoffführungswerk 200 is also provided.

The printing units 100 are designed as combinable modules that are identical, compact and easy to handle. They are adaptable to the width of the printing substrate 1.

• Im Ausführungsbeispiel sind die Druckwerke 100 als elektrografische Druckwerke ausgeführt, wie sie z.B. aus EP 0 727 720 B1 bekannt sind. Sie weisen eine Druckeinheit 110 mit einem Bilderzeugungselement 111, einer Ladestation 112, einer Bildbelichtungsstation 113, einer Entwicklerstation 114 und einer Bilderzeugungselement- Reinigungsstation 115 auf. Das Bilderzeugungselement 111 kann einen Fotoleiter, wie eine Fotoleitertrommel oder ein Fotoleiterband aufweisen. Die Belichtungsstation 113 kann ein LED- Zeichengenerator oder Laser sein. Die Entwicklerstation 114 kann als elektrophoretische Flüssigentwicklerstation realisiert sein.
• Beispielsweise kann die Entwicklerstation 114 eine Entwicklerwalze aufweisen, die einen Flüssigentwickler an dem Bilderzeugungselement 111 vorbeitransportiert derart, dass die Tonerablagerung auf dem Bilderzeugungselement 111 unabhängig von dessen Geschwindigkeit ist. Als Flüssigentwickler kann eine hochohmige Trägerflüssigkeit vorgesehen werden, in der Tonerteilchen dispergiert sind. Beispiel einer derartigen Trägerflüssigkeit ist Silikonöl. Die Tonerteilchen können vorzugsweise einen Durchmesser von ca. 1 µm aufweisen.

Structure of a single module = printing unit 100:

• In the exemplary embodiment, the printing units 100 are designed as electrographic printing units, as for example from EP 0 727 720 B1 are known. They include a printing unit 110 having an imaging element 111, a loading station 112, an image exposure station 113, a developer station 114 and an imaging element cleaning station 115. The imaging element 111 may comprise a photoconductor such as a photoconductor drum or a photoconductor belt. The exposure station 113 may be an LED character generator or laser. Developer station 114 may be implemented as an electrophoretic liquid developer station.
• For example, the developer station 114 may include a developer roller that carries a liquid developer past the imaging member 111 such that the toner deposition on the imaging member 111 is independent of its speed. As a liquid developer, a high-resistance carrier liquid may be provided in which toner particles are dispersed. Example of such a carrier liquid is silicone oil. The toner particles may preferably have a diameter of about 1 micron.

In addition, the toner concentration in the liquid developer is selected such that there are so many toner particles in the developer gap between developer roller and imaging member 111 that upon complete deposition of all or nearly all of the toner particles in the developer gap, the desired coloration of the charge images occurs. Preferably, the developer gap should be 5 to 10 .mu.m and the mobility of the toner particles in the developer gap such that during the residence time of the toner particles in the developer gap as possible all toner particles under the influence of over the einzärenden imaging element 111 electric field strength traverse the developer gap and on the inked Surface of the imaging element 111 are deposited.

• Benachbart dem Bilderzeugungselement 111 (F) ist eine Entwicklerwalze 203 angeordnet, die den Tonerteilchen aufweisenden Flüssigentwickler an dem Bilderzeugungselement 111 (F) vorbeiführt und von dem Tonerteilchen zum Bilderzeugungselement 111 (F) entsprechend den zuvor erzeugten Ladungsbildern übergehen.
• Benachbart der Entwicklerwalze 203 ist eine Rasterwalze 202 angeordnet, in dessen Rasterung der Flüssigentwickler zur Entwicklerwalze 203 transportiert wird.
• Benachbart zur Rasterwalze 202 ist eine eine Dosierrakel R2 aufweisende Kammerrakel 201 angeordnet, von der die Rasterwalze 202 über die Dosierrakel R2 den Flüssigentwickler übernimmt, deren Lage zur Rasterwalze 202 einstellbar ist und die derart ausgebildet ist, dass die Dosierrakel R2 von Flüssigentwickler überflutet ist.

An advantageous developer station 114 may have the following structure, Fig. 4 :

• Adjacent to the image forming member 111 (F), there is disposed a developing roller 203 which passes the toner-developer liquid developer past the image forming member 111 (F) and transfers from the toner particle to the image forming member 111 (F) in accordance with the previously formed charge images.
• Adjacent to the developer roller 203, an anilox roller 202 is arranged, in the screening of which the liquid developer is transported to the developer roller 203.
• Adjacent to the anilox roller 202, a doctor blade R2 having a doctor blade 201 is arranged, of which the anilox roller 202 takes over the metering blade R2, the liquid developer whose position is adjustable to the anilox roller 202 and which is designed such that the metering blade R2 is flooded by liquid developer.

The printing unit 100 further has a transfer unit 120 from a transfer element 121, preferably a transfer roller or a transfer belt, and from a transfer station 123 with one or more rollers. The transfer station 123 can be combined with transfer tools preferably a corona device.

Furthermore, the transfer unit 120 may have a toner image conditioning station 122, preferably a roller or a belt in contact with the transfer element 121, which may optionally be electrically adjustable or tempered. In addition, the transfer unit 120 may include a cleaning station 124 for cleaning the transfer member 121, e.g. is realized as a blade-roller or fleece cleaning.

The printing unit 100 further has a printing unit drive unit 130 with a power electronics 131 and a digital electronics 132. The power electronics 131 is associated with the motor controls and high voltage supplies the printing unit 110 and the transfer unit 120, the digital electronics 132, such as a microprocessor control, is used to realize Process control in interaction with the central control unit 400 ( Fig. 7 ), preferably the signal processing including the interface control to sensors of the printing unit 110 and the transfer unit 120, respectively.

The printing unit 100 can additionally have a secondary and auxiliary process unit 140 with a colorant supply station 141, and / or with a printing material conditioning station 142, preferably for paper moistening, and / or with a filter and suction station 143, preferably for the developer station or for the corona device.

Finally, the printing unit 100 has an image data processing unit 150, a controller.

• Der Aufbau einer Druckvorrichtung zum Bedrucken einer Endlos-Bedruckstoffbahn 1 ("Continuous Feet") ergibt sich aus Fig. 7. Hier sind Druckwerke 100 hintereinander geschaltet variierbar in der Anzahl entsprechend der zu erfüllenden Aufgabe. Gemeinsam ist den Druckwerken 100 das Bedruckstoffführungswerk (200). Dieses weist eine Bedruckstoffführungseinheit 220 innerhalb der Druckwerke 100, eine Bedruckstoffbahn- Spannungserzeugungsstation 211, und / oder eine Bedruckstoffbahn-Ausrichtstation 212, und / oder eine Bedruckstoffbahn-Abzugsstation 213 auf.

Structure of the modular printing device:

• The structure of a printing device for printing on a continuous printing substrate 1 ("continuous Feet") results from Fig. 7 , Here, printing units 100 are switched one behind the other variable in number according to the task to be performed. Common to the printing units 100 is the printing material guide mechanism (200). This comprises a printing material guide unit 220 within the printing units 100, a printing material web tensioning station 211, and / or a printing material web alignment station 212, and / or a printing material web take-off station 213.

The printing web tension generating station 211 may be a vacuum brake or an omega train, which is arranged at the entrance of the printing system. The printing material web alignment station 212 can be realized as a pivoting frame, which is also arranged at the entrance of the printing system. The printing material removal station 213 may be a conveyor roller pair, which is arranged at the output of the printing system.

At least one printed image conditioning unit can be provided between the printing units 100 and / or at the output of the printing system. Between the printing units 100 may be arranged as Druckbildkonditioniereinheit each have a unit for intermediate fixing 231, at the output of the printing system, a fuser 232, preferably an IR radiation fixation or heat-pressure fixation. The intermediate fixing unit 231 may be e.g. are also omitted in a working according to the electrophoretic principle printing unit 100.

Furthermore, a gloss station 233 can be provided at the output of the printing system.

• mit einer Leistungselektronik 241, vorzugsweise für Motorsteuerungen und Hochspannungsversorgungen innerhalb des Bedruckstoffführungswerkes 200,
• und / oder mit einer Digitalelektronik 242 (z.B. Mikroprozessorsteuerung) zur Realisierung der Regelabläufe zur Steuerung oder Regelung der Bedruckstoffführung im Zusammenspiel mit dem zentralen Steuerwerk 400 und/ oder zur Signalverarbeitung einschließlich Steuerung der Schnittstellen zu Sensoren des Bedruckstoffführungswerkes 200, der Umdruckeinheit(en) 123 sowie der Druckbild-Konditionier-Einheiten 231, 232, 233.

At least one electronic drive unit 240 is provided for controlling the printing material guide mechanism 200

• with a power electronics 241, preferably for motor controllers and high-voltage supplies within the printing material guide 200,
• and / or with a digital electronics 242 (eg microprocessor control) for the realization of the control processes for controlling or regulating the printing material guide in interaction with the central control unit 400 and / or signal processing including control of the interfaces to sensors of Bedruckstoffführungswerkes 200, the transfer unit (s) 123 and the print image conditioning units 231, 232, 233rd

The structure of the modular printing device for printing single sheets (cut sheet) can Fig. 8 be removed. In the following, only the Fig. 7 For the same components is explained in the explanation Fig. 7 directed. It should be noted that equal reference numerals have a "3" at the beginning rather than a "2".

A difference too Fig. 7 is seen in the Bedruckstoffführungswerk 300. This must be suitable for single-sheet / sheet-fed printing. The Bedruckstoffführungswerk 300 has a Bedruckstoffführungseinheit 310 with a conveyor belt 311 on which the single sheets or sheets 1 rest and through which they are moved through the printing system. Furthermore, a drive unit 340 is provided whose tasks correspond to the drive unit 240. These are referred to.

• eine zentrale Leistungselektronik 410,
• eine zentrale elektronische Drucker-Ansteuereinheit 420. Die zentrale Ansteuereinheit 420 steuert
• die Schnittestelle zur Bedruckstoff- Vor- und Nachverarbeitung,
• und / oder die Schnittstelle zu den Druckwerken 100,
• und / oder die Schnittstelle zum Bedruckstoffführungswerk 200 oder 300,
• und / oder die zentrale Druckersteuerung zur zeitgerechten Koordinierung aller Abläufe im Drucksystem sowie der gesamten Druckstraße.

Both in the printing device after Fig. 7 as well as at Fig. 8 a central control unit 400 is provided. This contains

• a central power electronics 410,
• a central electronic printer driver 420. The central driver 420 controls
• the interface for the substrate pre- and post-processing,
• and / or the interface to the printing units 100,
• and / or the interface to the printing material guide 200 or 300,
• and / or the central printer control for timely coordination of all processes in the printing system and the entire printing line.

The central power electronics 410 has a mains voltage switch - and backup system and the central power supply of the printing system.

• Im Ausführungsbeispiel der Fig. 6 ist ein Druckwerk 100 als elektrografisches Druckwerke ausgeführt, wie es z.B. aus EP 0 727 720 B1 bekannt ist. Es weist eine Druckeinheit 110 mit einem Bilderzeugungselement 111, einer Ladestation 112, einer Bildbelichtungsstation 113, einer Entwicklerstation 114 und einer Bilderzeugungselement- Reinigungsstation 115 auf. Das Bilderzeugungselement 111 kann einen Fotoleiter, wie eine Fotoleitertrommel oder ein Fotoleiterband aufweisen. Die Belichtungsstation 113 kann ein LED- Zeichengenerator oder Laser sein. Die Entwicklerstation 114 kann als elektrophoretische Flüssigentwicklerstation nach Fig. 2 realisiert sein.

c) Essential aspect of the invention: Electrographic printing device of variable printing speed:

• In the embodiment of Fig. 6 is a printing unit 100 designed as electrographic printing, as it eg EP 0 727 720 B1 is known. It has a printing unit 110 with an imaging element 111, a charging station 112, an image exposure station 113, a developer station 114 and an imaging element cleaning station 115. The imaging element 111 may comprise a photoconductor such as a photoconductor drum or a photoconductor belt. The exposure station 113 may be an LED character generator or laser. The developer station 114 can be used as an electrophoretic liquid developer station Fig. 2 be realized.

The printing unit 100 further has a transfer unit 120 from a transfer element 121, preferably a transfer roller or a transfer belt, and from a transfer station 123 with one or more rollers. The transfer printing station 123 can be combined with transfer printing aids, preferably a corona device.

Furthermore, the transfer unit 120 may have a toner image conditioning station 122, preferably a roller or a belt in contact with the transfer element 121, which may optionally be electrically adjustable or tempered. In addition, the transfer unit 120 may include a cleaning station 124 for cleaning the transfer element 121, which is realized, for example, as a blade-roller or fleece cleaning.

The printing unit 100 further has a printing unit drive unit 130 with a power electronics 131 and a digital electronics 132. The power electronics 131 are associated with the motor controls and high voltage supplies of the printing unit 110 and the transfer unit 120, the digital electronics 132, e.g. a microprocessor control, is used to implement process controls in interaction with the central control unit 400, preferably the signal processing including the interface control to sensors of the printing unit 110 and the transfer unit 120th

The printing unit 100 can additionally have a secondary and auxiliary process unit 140 with a colorant supply station 141, and / or with a printing material conditioning station 142, preferably for paper moistening, and / or with a filter and suction station 143, preferably for the developer station or for the corona device.

Finally, the printing unit 100 has an image data processing unit 150, a controller.

• Eine Entwicklerwalze 203 mit einer elastischen Beschichtung 206;
• eine Rasterwalze 202 mit einer Rasterung aus darauf angeordneten Vertiefungen (Näpfchen), es können auch mehrere Rasterwalzen vorgesehen werden; die Rasterung kann je nach Anwendungsfall unterschiedlich ausgeführt sein;
• eine in ihrer Position gegenüber der Rasterwalze veränderbare Kammerrakel 201;
• eine Reinigungseinrichtung mit einer Reinigungswalze 204 und einem Reinigungselement 205.

The developer station E the FIG. 4 has the following components:

• A developer roller 203 having an elastic coating 206;
• an anilox roller 202 with a grid of recesses arranged thereon (wells), it can also be provided a plurality of anilox rollers; the screening can be carried out differently depending on the application;
• a in its position relative to the anilox roll variable chamber blade 201;
• a cleaning device with a cleaning roller 204 and a cleaning element 205.

The developer roller 203 contacts an image carrier element F, eg a photoconductor of a photoconductor belt or a roller, with photoconductor layer disposed thereon. On the image carrier element F, the charge images are present, which are to be colored with toner particles.

Can be used for this purpose suitable for electrophoretic development liquid developer with distributed therein colorant (toner particles) as he eg EP 0 756 213 B1 or EP 0 727 720 B1 is known. The liquid developer is transported through the developer roller 203 through a developer gap between the image-bearing member F and the developer roller 203. There, the toner particles are transferred to the image bearing member F according to the development process described above.

The supply of the liquid developer for imagewise coloring of the image carrier member F with toner particles via the chambered doctor blade 201 and the anilox roller 202 to the developer roller 203. The cleaning of the inverse residual image of the developer roller 203 in turn takes place by its transfer to the cleaning roller 204 and removal of the liquid developer from the cleaning roller 204 by a cleaning element 205, eg a squeegee. From the purifier 204, 205, the removed liquid developer may be returned to a liquid developer supply reservoir (not shown).

The developer roller 203, anilox roller 202, and cleaning roller 204 advantageously rotate at constant speed ratios to one another (surface speeds), preferably at a ratio of 1: 1: 1. The direction of rotation of the developer roller 203 and the image-bearing member F may be the same or opposite, that of the developer roller 203 and the anilox roller 202 and the developer roller 203 and the cleaning roller 204 may be the same direction or opposite. Defined potentials for targeted field effect on the charged toner particles can be applied to them.

The developer roller 203 has an elastic coating 206 and is in contact with the image bearing member F, the screen roller 202, and the cleaning roller 204.

The raster roller 202 is realized in its screening to promote a matched to the speed of the image carrier element F volume of liquid developer of, for example, 1 to 40 cm ³ / m ² (based on the roll surface). The promotion of liquid developer is area-related and thus independent of the printing speed, ie at different printing speeds, the same amount of liquid developer per unit area of the developer roller 203 can always be supplied.

• durch definierte Verformung der elastischen Beschichtung 206 der Entwicklerwalze 203 vorzugsweise über Federkraft-Zustellung zu benachbarten Elementen, wie z.B. Bildträgerelement F, Rasterwalze 202 oder Reinigungswalze 204;
• durch die inkompressible Schicht des Flüssigentwicklers zwischen Entwicklerwalze 203 und Bildträgerelement F, Entwicklerwalze 203 und Reinigungswalze 204 oder Entwicklerwalze 203 und Rasterwalze 202.

The formation of defined action zones for the transition of liquid developer between developer roller 203 and image carrier element F, developer roller 203 and cleaning roller 204 and developer roller 203 and anilox roller 202 can be achieved in various ways:

• by defined deformation of the elastic coating 206 of the developer roller 203 preferably via spring force delivery to adjacent elements, such as image carrier element F, anilox roller 202 or cleaning roller 204;
• through the incompressible layer of the liquid developer between developer roller 203 and image carrier element F, developer roller 203 and cleaning roller 204 or developer roller 203 and anilox roller 202.

The developed charge images on the image carrier element F are finally transferred directly or via a transfer roller to a recording medium. This process can be done in a known manner, eg as it is in EP 0 727 720 B1 is described.

LIST OF REFERENCE NUMBERS

F

Image-bearing member

PM

print module

e

Developer station in the printing module PM

R1

Locking scraper of the chambered doctor blade

R2

Dosierrakel der Kammerrakel

1

Record carrier, final image carrier, substrate

2

deflecting

201

chambered doctor blade

202

anilox roller

203

developer roller

204

cleaning roller

205

cleaning element

206

elastic coating of the developer roller

207

Chamber of the chambered doctor

300

transfer roller

100

printing unit

110

Printing unit (e.g., electrographic printing unit)

111

Image-forming element (e.g., photoconductor, OPC a-Si)

112

Charging station (e.g., corona device)

113

Image exposure station (e.g., LED character generator or laser)

114

Developer station (e.g., electrophoretic liquid developer station)

115

Imaging element cleaning station (e.g., blade, roller and / or nonwoven cleaning)

120

transfer unit

121

Transfer element (e.g., transfer roller or transfer belt)

122

Toner image conditioning station (for example roller or belt in contact with the transfer element, if necessary electrically adjustable, possibly temperature-controllable, corona device, IR heater)

123

Transfer station (eg one or more rollers, possibly combined with transfer printing aids such as corona devices, blades)

124

Transfer element cleaning station (e.g., blade, roller, and / or nonwoven cleaning)

130

Power electronics (eg motor controls and high voltage power supplies)

131

Digital electronics (for example microprocessor control (HW and SW) for realizing complex process control in conjunction with the central control unit 400, possibly signal processing including interfaces to sensors of the printing unit 110 or the transfer unit 120)

140

Secondary and auxiliary process unit

141

Colorant feed station (e.g., for the electrophoretic developer station)

142

Substrate conditioning station (for example for paper moistening)

143

Filter and suction station (e.g., for developer station or for corona equipment)

150

Image data processing unit (controller)

200

Continuous Feet Feed Tray Continuous Feet Feed Station (e.g., Vacuum Brake or Omega Pull) Stock Tray Alignment Station (e.g., Swing Frame) Stock Tray Feed Station (e.g., Conveyor Roll Pair)

220

Bedruckstoffführungseinheit

221

Transfer station (identical to 123)

230

Print image conditioning unit (s)

231

Intermediate conditioning station (e.g., intermediate fixation, Si oil removal) fixation station (e.g., IR radiation fixation, heat-pressure fixation) gloss station

240

Electronic substrate guide drive unit

241

Power electronics (eg motor controls and high voltage power supplies)

242

Digital electronics (eg microprocessor control (HW and SW) for the realization of the control sequences for controlling / regulating the printing material guide in interaction with the central control unit 400, possibly signal processing including interfaces to sensors of the printing material guide unit 220, as well as the print image conditioning units 230)

300

Printing material guide for single sheet / sheet printing ("Cut Sheet")

310

Bedruckstoffführungseinheit

311

Single-sheet transport element (eg conveyor belt, if necessary with defined electrical conductivity)

320

Transfer printing unit (s)

321

Transfer station (identical to 123)

330

Print image conditioning unit (s)

331

Intermediate conditioning station (e.g., intermediate fixation, Si oil decrease)

332

Fixation station (e.g., IR radiation fixation, heat-pressure fixation)

333

Gloss station

340

Electronic substrate guide drive unit

341

Power electronics (eg motor controls and high voltage power supplies)

342

Digital electronics (eg microprocessor control (HW and SW) for realizing the control processes for controlling / regulating the printing material guide in interaction with the central control unit 400, if necessary signal processing including interfaces to sensors of the printing material guiding unit 310, the transfer unit (s) 320 and the print image conditioning units 330)

400

Central control unit

410

Central power electronics

411

Mains voltage switch and fuse system

412

Central power supply for printing units and printing guide 200 or 300

420

Central electronic printer driver

Claims (12)

1. An electrographic printing device comprised of an image generating system that generates an electronic charge image on an image carrier element, which electronic charge image is made visible by means of a developer station via charged ink particles (toner particles) and is subsequently transferred onto a final image carrier and fixed thereon,
   in which means are provided in order to be able to continuously vary the speed of the image carrier element (F) from 0 up to a limit speed,

   - which means adapt the charge intensity of the image carrier element (F) to its speed,

   - which means adapt the exposure intensity in the imagewise exposure of the image carrier element (F) to its speed, and

   - which means keep the supply of toner to the image carrier element (F) constant per area.
2. The printing device according to claim 1,
   in which the charge intensity is adapted with regard to the speed of the image carrier element (F).
3. The printing device according to claim 1 or 2,
   in which the electronic character generation is adapted to the speed of the image carrier element (F) with regard to the information location and energy per area, such that in the electrographic process the charge image, with regard to form and potential values, is always created in the same manner independent of the speed of the image carrier element (F).
4. The printing device according to one of the claims 1 to 3,
   in which the developer station is designed such that the signal distribution on the image carrier element (F) is developed independent of its speed, such that during the development process identical potential distributions on the image carrier element (F) always generate the same toner distributions on the charge images.
5. The printing device according to claim 4,
   in which the process parameters, such as photoconductor potential, light energy, auxiliary potential across the developer gap, toner concentration, are variable for the case that the development of the charge image is not entirely independent of the speed of the image carrier element (F) such that the toner image deposition on the image carrier element (F) is nearly identical at different speeds.
6. The printing device according to one of the claims 1 to 5,
   in which the process parameters such as auxiliary potential between image carrier element (F) and final image carrier (1), between image carrier element (F) and intermediate carrier, between intermediate carrier and final image carrier (1) are variable for the case that the transfer of the toner image onto the final image carrier (1) directly or respectively, via an intermediate carrier is not entirely independent of the speed of the image carrier element (F) such that the toner image deposition on the final image carrier is nearly identical at different speeds.
7. The printing device according to claim 1,
   in which the inking of the image carrier (F) by the developer station occurs according to the electrophoretic principle and in which in the developer station (200) a developer roller (203) is provided which transports a liquid developer past the image carrier element (F) such that the toner deposition on the image carrier element (F) is independent of its speed.
8. The printing device according to claim 7,
   in which the toner concentration in the liquid developer is selected such that so many toner particles are located in the developer gap between the developer roller (203) and image carrier element (F) that given complete deposition of all toner particles located in the developer gap the desired inking of the charge images is created.
9. The printing device according to one of the claims 1 to 8 with a developer station

   - in which a developer roller (203) is arranged adjacent to the image carrier element (F) which developer roller (203) directs liquid developer comprising the toner particles past the image carrier element (F) and from which developer roller (203) toner particles cross over to the image carrier element (F) corresponding to the previously-generated charge images,

   - in which a raster roller (202) is arranged adjacent to the developer roller (203), in the rastering of which raster roller (202) the liquid developer is transported to the developer roller (203),

   - in which a chamber scraper (201) comprising a dosing scraper (R2) is arranged adjacent to the raster roller (202), from which chamber scraper (201) the raster roller (202) accepts the liquid developer via the dosing scraper (R2), the position of which chamber scraper (201) is adjustable relative to the raster roller (202) and which chamber scraper (201) is designed such that the dosing scraper (R2) is overflowed by liquid developer.
10. The printing device according to one of the claims 7 to 9,
    in which a cleaning device (204, 205) is arranged adjacent to the developer roller (203) for removal from the developer roller (203) of the liquid developer comprising the inverse residual image, which cleaning device (204, 205) accepts the residual image.
11. A method for the operation of an electrographic printing device with variable printing speed using a printing device according to the claims 1 to 10.
12. The method according to claim 11,
    in which the charge intensity is adapted with regard to information location and energy per area to the speed of the image carrier element (F).

Images