JP6095459B2 - Digital printer for printing on a recording support - Google Patents

Description

  The present invention relates to a digital printer that prints on a recording support using toner particles attached by a liquid developer, and more particularly to a high-speed printer that prints on a web-like or sheet-like recording support.

  In such a digital printer, the latent charge image on the electrostatic charge image carrier is colored by electrophoresis using a liquid developer. The toner image thus formed is transferred to the recording support indirectly or directly via a transfer element. The liquid developer has a desired ratio of toner particles to liquid carrier. Mineral oil is preferably used as the liquid carrier. In order to give an electrostatic charge to the toner particles, a charge control agent is added to the liquid developer. For example, additional additives are added to obtain the desired viscosity or desired drying characteristics of the liquid developer.

  Such a digital printer is already known for example in German Patent Application No. 102010015985, German Patent Application Publication No. 102008048256 or German Patent Application Publication No. 1090060334. ing.

  In order to color the electrostatic image on the electrostatic image carrier, the developer station guides the liquid developer alongside the electrostatic image carrier. The development station includes development elements such as a development roller (the development roller guides the liquid developer through the electrostatic image carrier) and a supply system (the supply system supplies the liquid developer to the development roller). And a cleaning unit (the cleaning unit removes residual liquid developer remaining on the developing roller after coloring the electrostatic image on the electrostatic image carrier). The cleaning unit includes, for example, a cleaning roller, and the cleaning roller removes the residual liquid developer from the developing roller. In this case, for example, an electric field is generated between the developing roller and the cleaning roller. Facilitate agent migration. The residual liquid developer can be scraped off from the cleaning roller by a doctor. In this case, the residual liquid developer should not stay on the cleaning roller. This is because when the residual liquid developer stays on the cleaning roller, it can reach the developing roller again.

  A developing station comprising such a cleaning unit is known from German Offenlegungsschrift DE 102000008211, DE 102004032922 or DE 102009005371. . Furthermore, it is known in rotary printing presses to arrange a cleaning doctor system on the coating roller (German utility model registration No. 29918488), which consists of a working doctor and a closed doctor, in this case The chamber formed is filled with a cleaning liquid, and the coating liquid is cleaned against dirt by the cleaning liquid. An ultrasonic vibration system in the chamber assists in cleaning.

German Patent Application Publication No. 102010015985 German Patent Application Publication No. 102008048256 German Patent Application Publication No. 102009060334 German Patent Application Publication No. 102010008211 German Patent Application Publication No. 102004032922 German Patent Application Publication No. 102009005371 German utility model registration No. 29918488 specification

  An object of the present invention is to improve a digital printer for printing on a recording support and to have a high process stability by minimizing the load of liquid developer by reducing mechanical stress (pressure), And it is providing the thing which has high printing quality by the invariant characteristic of a liquid developer. In particular, a cleaning unit for a developing element, such as a developing roller, provided in a developing station should be implemented so that the cleaning of the developing element is optimal, with only a slight load applied to the liquid developer. is there.

  In order to solve this problem, according to the present invention, a digital printer that performs printing on a recording support, at least one station that forms an electrostatic image of an image to be printed on an electrostatic image carrier, and a liquid At least one printing section having at least one development station for coloring an electrostatic charge image on the electrostatic image carrier using a developer, the development station comprising a development element, the development element comprising an electrostatic charge image A supply system for coloring the electrostatic image on the carrier and applying a liquid developer to the developing element is provided, the cleaning element for removing residual liquid developer remaining on the developing element after the development of the electrostatic image, and the cleaning element A cleaning unit comprising doctor means for contact and supply means for arriving fluid at the doctor means in the region of the contact zone between the cleaning element and the doctor means For example, between the supply system and the doctor means, as the supply means and the flow guiding element is arranged, through a flow guide element, the liquid developer flows in the doctor unit as a fluid.

  Preferably, a flow guide element is arranged as supply means between the overflow of the supply system for liquid developer and the doctor means, via which the liquid developer is used as fluid. Flows to doctor means.

  Preferably, a collecting groove is arranged as a flow guide element between the metering means abutting on the developing element and the doctor means, and is removed from the developing element by the metering means via the collecting groove. Liquid developer flows toward the doctor means.

  Preferably, the flow guide element is arranged in the supply system or metering means so that the liquid developer diluted with respect to the toner flows towards the doctor means.

  Preferably, a cleaning unit comprising at least one cleaning nozzle is provided as supply means, which sprays fluid onto the doctor means from above or below.

  Preferably, the doctor means and the cleaning element are at the same potential.

  Preferably, the doctor means is fixed to a pivotally supported doctor holder, which preloads the doctor means towards the cleaning element.

  Preferably, the doctor means comprises a cleaning doctor and a shield doctor, which together form a doctor chamber, the doctor chamber such that the fluid wets the cleaning element and the doctor edge. Filled with fluid.

  Preferably, the cleaning doctor and the shield doctor abut against the cleaning element so as to be pulled by the cleaning element.

  Preferably, the cleaning doctor and shield shield abut against the cleaning element such that the cleaning doctor is pulled by the cleaning element and the shield doctor is pushed by the cleaning element.

  A digital printer that prints on a recording support includes at least one station for forming an electrostatic charge image of an image to be printed on the electrostatic image carrier, and an electrostatic charge on the electrostatic image carrier using a liquid developer. At least one printing section having at least one development station for coloring the image.

The development station
A developing element, for example a developing roller or an endless developing belt, the developing element coloring the electrostatic image on the electrostatic image carrier with toner,
Comprising a supply system for applying a liquid developer to the developing element;
A cleaning element for removing liquid developer remaining on the developing element after development of the electrostatic charge image, for example a cleaning roller or a cleaning belt, a doctor means abutting the cleaning element, and at least a cleaning element for fluid, for example liquid developer And a supply means for arriving at the doctor means in the region of the contact zone between the doctor means and the doctor means.

  Preferably, the doctor means is a doctor abutting the doctor element, the fluid for wetting the doctor is derived from the supply system, which applies the liquid developer to the development element.

  Preferably, excess liquid developer that is not transferred to the developing element (the excess liquid developer is diluted with respect to the toner) is directed towards the doctor means via the flow guide element.

  Moreover, it is also preferable to spray a fluid such as a liquid developer on the doctor in a region centered on the doctor edge as desired.

  More preferably, a potential element is arranged in the flow guide element next to the doctor, and this potential element acts on the toner on the cleaning element such that the toner is unwound.

  In another aspect, the doctor means can be configured as a unit consisting of two doctors (cleaning doctor and shield doctor), which together form a doctor chamber, and the chamber doctor comprises both doctors. The edges are filled with fluid so that they are wetted with fluid.

  Preferably, the doctor means is arranged on a pivotally supported doctor holder, which applies a predetermined preload on the doctor means towards the cleaning element. In the case of a newly used doctor, the edge of the doctor rests on the cleaning element under an increased preload, in which case the increased wear on the doctor means only at the beginning of the rotation of the cleaning element. Arise. Subsequently, the doctor means abuts the cleaning element exclusively under a preload such that the wear of the doctor means is slight, so that a long service life of the doctor means is obtained.

FIG. 1 is a diagram illustrating a digital printer in one exemplary configuration of a digital printer. It is a figure which shows the schematic structure of the printing part of the digital printer by FIG. It is a figure which shows the printing part which has the 1st structure of a developing station. It is a figure which shows the 2nd structure of a developing station. It is a figure which shows a cleaning unit. It is a figure which shows the holder of a doctor. It is a figure which shows another cleaning unit for developing rollers. It is a figure which shows another cleaning unit for developing rollers. It is a figure which shows another cleaning unit for developing rollers.

  Next, embodiments of the present invention will be described in detail using the illustrated embodiments.

  As shown in FIG. 1, a digital printer 10 that prints on a recording support 20 includes one or more printing units 11a to 11d and 12a to 12d, and the printing units 11a to 11d and 12a to 12d are toners. An image (printed image 20 ′, see FIG. 2) is printed on the recording support 20. As shown in the figure, a web-like recording support 20 is fed out from a roll 21 using a feeding device 22 and supplied to the first printing unit 11a as the recording support 20. In the fixing unit 30, the printed image 20 ′ is fixed to the recording support 20. Next, the recording support 20 is wound around a roll 28 using a winding device 27. Such a configuration is also called a roll-to-roll.

  In the preferred configuration shown in FIG. 1, the web-like recording support 20 is full-color printed by four printing sections 11a to 11d on the front surface and four printing sections 12a to 12d on the back surface (so-called 4 / 4 configuration). For this purpose, the recording support 20 is fed from the roll 21 by the feeding device 22 and supplied to the first printing unit 11a via the adjusting unit 23 that is selectively provided. In the adjusting section 23, the recording support 20 can be pretreated or coated with a suitable material. As a coating material (also referred to as a primer), a wax or a chemically equivalent material may be preferably used.

  Such material can be applied over the entire surface of the recording support 20 or only where it is desired to be printed later, whereby the recording support 20 is prepared for printing and / or a printed image 20 '. It is possible to affect the adsorption characteristics of the recording support 20 when wearing. This ensures that later applied toner particles or liquid carrier do not penetrate too deeply into the recording support 20 and generally remain on the surface (thus improving color and image quality).

  Next, the recording support 20 is first sequentially supplied to the first printing units 11a to 11d. In the first printing units 11a to 11d, printing is performed exclusively on the surface. Each of the printing units 11a to 11d has, in a general form, a different color or a different type of toner material such as MICR toner (this toner can be read electromagnetically) on the recording support 20 in a general form. To print.

  After printing the front surface, the recording support 20 is reversed by the reversing unit 24 and supplied to the remaining printing units 12a to 12d for printing on the back surface. Optionally, another adjustment unit (not shown) may be arranged in the area of the reversing unit 24, by which the recording support 20 is prepared for backside printing, for example pre-printed. Fixing (partial fixing) or other adjustment of the printed surface image (or the entire front surface or back surface) is performed. Therefore, it is possible to prevent the surface print image from being mechanically damaged by the subsequent printing unit during the subsequent conveyance.

  In order to realize full-color printing, at least four colors (and thus at least four printing units 11 and 12) are required, and for example, primary colors YMCK (yellow, magenta, cyan, and black) are also required. Further printing units 11, 12 with special colors (for example, customer-specific colors or additional primary colors in order to extend the printable color space) may be used.

  A register unit 25 is arranged on the downstream side of the printing unit 12d, and the register unit 25 evaluates the registration mark. The registration mark is printed on the recording support 20 independently of the printed image 20 '(especially outside the printed image 20'). As a result, the horizontal and vertical registers (multiple primary color points forming one color point should be placed one above the other or in close proximity to each other, which is the same for both color and four color registers. As well as the registers (the front and back surfaces must match exactly in position), which results in a qualitatively good printed image 20 '.

  A fixing unit 30 is disposed on the downstream side of the register unit 25, and the printed image 20 ′ is fixed on the recording support 20 by the fixing unit 30. In the electrophoretic digital printer, a heat dryer is preferably used as the fixing unit 30, and the heat dryer almost evaporates the liquid carrier, so that only the toner particles remain on the recording support 20. This is done by applying heat. At this time, when the toner particles include a material that can be melted based on a thermal action, for example, a resin, the toner particles may also melt on the recording support 20.

  A tension portion 26 is disposed on the downstream side of the fixing unit 30, and the tension portion 26 pulls the recording support 20 through all the printing portions 11 a to 12 d and the fixing unit 30. In this region, no other driving device is arranged. This is because the printed image 20 ′ that has not been fixed yet may be rubbed by the frictional driving device for the recording support 20.

  The tension unit 26 supplies the recording support 20 to the winding device 27, and the winding device 27 winds up the printed recording support 20.

  Next to the printing units 11, 12 and the fixing unit 30, in the center, all supply devices for the digital printer 10, such as an air conditioning module 40, an energy supply device 50, a controller 60 and a liquid management module 70 (e.g. A liquid control unit 71 and a storage container 72) are arranged. To supply the digital printer 10 as a liquid, in particular a pure liquid carrier, a highly concentrated liquid developer (high content of toner particles relative to the liquid carrier) and a medium liquid (Serum; Salem, liquid developer + charge control) As well as a waste container for the liquid to be discarded or a container for the cleaning liquid.

  The digital printer 10 is assembled in a modular manner in printing units 11 and 12 having the same structure. The printing units 11 and 12 are not distinguished mechanically, but are simply distinguished by the liquid developer (toner color or toner type) used there.

  The basic structure of the printing units 11 and 12 is shown in FIG. Such a printing part is based on the electrophotographic principle, in which the photoelectric image carrier is colored and thus formed using a liquid developer containing charged toner particles. The image is transferred to the recording support 20.

  The printing units 11 and 12 mainly include an electrophotographic station 100, a developing station 110, and a transfer station 120.

  The main part of the electrophotographic station 100 is a photoelectric image carrier, and this image carrier has a photoelectric layer on its surface (so-called photoconductor (photoconductor)). In the embodiment of FIG. 2, the photoconductor is configured as a drum (photoconductor drum 101) and has a hard surface. The photoconductor drum 101 rotates through various components for forming the printed image 20 '(rotation in the direction of the arrow).

  In the photoconductor, any contaminants are first cleaned. For this reason, removal light 102 is present, which removes the charge that still remains on the surface of the photoconductor. The removal light 102 can be equalized (locally adjustable) to obtain a uniform light distribution. As a result, the surface can be pretreated uniformly.

  Downstream of the removal light 102, the cleaning device 103 mechanically removes the photoconductor to remove toner particles, possibly dirt particles and possibly residual liquid carriers still present on the surface of the photoconductor. Clean to formula. The removed liquid carrier is supplied to the collection container 105. The collected liquid carrier and toner particles are processed (optionally filtered) and fed to one of the corresponding liquid ink reservoirs, i.e. storage containers 72, depending on the color (see arrow 105 ').

  The cleaning device 103 preferably comprises a doctor 104, which contacts the outer peripheral surface of the photoconductor drum 101 at an acute angle (about 10 ° to 80 ° with respect to the exit surface), whereby the surface is , Mechanically cleaned. The doctor 104 can reciprocate laterally with respect to the direction of rotation of the photoconductor drum 101 so that the outer peripheral surface is cleaned over its entire axial length with as little wear as possible.

  Next, the photoconductor is charged to a predetermined electrostatic potential by the charging device 106. A plurality of corotrons (especially glass-coated corotrons) are preferably provided for charging. The corotron is composed of at least one wire 106 ', and a high voltage is applied to the wire 106'. This voltage causes air to be ionized around the wire 106 '. A shield 106 ″ is provided as a counter electrode. The corotron is additionally vented with fresh air, which is supplied between the shields through special air passages (inlet air passage 107 for supply air and outlet air passage 108 for exhaust). (See also air flow arrow in FIG. 2). The supplied air is then uniformly ionized at the wire 106 '. This provides a uniform and even charge of the surface of the photoconductor located near the wire 106 '. With dry, heated air, uniform charging can be further improved. Air is led out via the lead-out air passage 108. Ozone generated in some cases can likewise be sucked out via the outlet air passage 108.

  The corotrons are arranged in stages, ie two or more wires 106 'are provided for each shield 106 "with the same shield voltage. The current flowing through the shield 106 "can be adjusted so that the charging of the photoconductor can be controlled. The corotrons can be energized with different strengths, which results in an even and sufficient charge along the photoconductor.

  A character generator 109 is disposed downstream of the charging device 106, and the character generator 109 discharges the photoconductor for each pixel in accordance with a desired print image 20 'through optical radiation. This produces a latent image that is later colored by toner particles (the colored image matches the printed image 20 '). Preferably, an LED character generator 109 is used, in which LED lines having a large number of individual LEDs are fixedly arranged over the entire axial length of the photoconductor drum 101. The number of LEDs and the size of the optical imaging point on the photoconductor determine, among other things, the resolution of the printed image 20 '(typical resolution is around 600 x 600 dpi). The LEDs can be individually controlled with respect to time and radiation output. Thus, a multi-level method can be used to form a halftone dot (consisting of multiple pixels or pixels), or the pixels can be delayed in time so that, for example, incorrect color registration or correction in the case of a register is electronic It can be performed optically.

  The character generator 109 has control logic that must cool based on the number of LEDs and their radiant output. Preferably, the character generator 109 is cooled by liquid. The LEDs can be controlled on a group-by-group basis (multiple LEDs are grouped together to form a group) or individually.

Latent image formed by the character generator 109 is colored with the toner particles by the developing stations 110. For this purpose, the developing station 110 comprises a rotating developing roller 111, which guides the liquid developer layer towards the photoconductor (the functional form of the developing station 110 will be described in detail later). ). The surface of the photoconductor drum 101 is relatively hard, the surface of the developing roller 111 is relatively soft, and both rollers are pressed against each other, so a thinner and higher (longer) nip (between the rollers) In this nip, charged toner particles move electrophoretically from the developing roller 111 to the image conductor portion of the photoconductor based on the electric field. In the non-image area, the toner does not migrate to the photoconductor. The nip filled with the liquid developer has a predetermined height (gap thickness). This height is related to the mutual pressure of both rollers 101, 111 and the viscosity of the liquid developer. Typically, the height of the nip is in the range of greater than about 2 μm to about 20 μm (the value also varies depending on the viscosity of the liquid developer). The nip length is approximately a few millimeters.

  The colored image rotates together with the photoconductor drum 101 to the first transfer position, and the colored image is almost completely transferred to the transfer roller 121 at the first transfer position. The transfer roller 121 moves in the same direction as the photoconductor drum 101 at the first transfer position (nip between the photoconductor drum 101 and the transfer roller 121), and preferably the same as the photoconductor drum 101. Exercise at speed. After transferring the print image 20 ′ to the transfer roller 121, the print image 20 ′ (toner particles) is selectively transferred to a charging unit 129, such as a corotron, in order to transfer the toner particles to the recording support 20 later. Later charged or charged.

  The recording support 20 runs between the transfer roller 121 and the opposing roller (pressure roller) 126 in the conveyance direction 20 ″. The contact area (nip) forms a second transfer position, and the toner image is transferred to the recording support 20 at the second transfer position. The transfer roller 121 moves in the same direction as the recording support 20 in the second transfer region. The opposing roller 126 also rotates in the same direction in the nip region. The speeds of the transfer roller 121, the opposing roller 126, and the recording support 20 are harmonized with each other at the transfer position, and preferably the same, so that the printed image 20 'is not rubbed and soiled. At the second transfer position, the print image 20 ′ is transferred to the recording support 20 in an electrophoretic manner based on the electric field between the transfer roller 121 and the opposing roller 126. Further, the opposing roller 126 pushes the relatively soft transfer roller 121 with a high mechanical force, so that the toner particles remain attached to the recording support 20 based on the adhesion.

  Since the surface of the transfer roller 121 is relatively soft and the surface of the facing roller 126 is relatively hard, a nip is formed during rolling, and toner transfer is performed in this nip. As a result, the undulations of the recording support 20 can be compensated, so that the recording support 20 can perform printing without a gap. Such a nip is also well suited for printing on a relatively thick or non-planar recording support 20, for example in the case of packaging printing.

  Although it is desirable to completely transfer the printed image 20 ′ to the recording support 20, some toner particles may undesirably remain on the transfer roller 121. A part of the liquid carrier remains on the transfer roller 121 due to wetting. In some cases, toner particles still present should be removed almost completely by the cleaning unit 122 following the second transfer position. The liquid carrier still present on the transfer roller 121 can also be removed from the transfer roller 121 completely or to a predetermined layer thickness, so that from the photoconductor drum 101 downstream (rear) of the cleaning unit 122. The same condition is mainly established by the prescribed layer thickness including the liquid developer on the clean surface or the surface of the transfer roller 121 on the upstream side (front side) of the first transfer position to the transfer roller 121.

  The cleaning unit 122 is preferably configured as a wet chamber including a cleaning brush 123 and a cleaning roller 124. In the region of the brush 123, a cleaning liquid (eg, a liquid carrier or a unique cleaning liquid may be used) is supplied via a cleaning liquid supply path 123 '. The cleaning brush 123 rotates in the cleaning liquid, and at that time, the surface of the transfer roller 121 is “brushed”. Thereby, the toner adhering to the surface is dissociated.

  The cleaning roller 124 is at a potential opposite to the charge of the toner particles. Therefore, the charged toner is removed from the transfer roller 121 by the cleaning roller 124. Since the cleaning roller 124 contacts the transfer roller 121, the cleaning roller 124 also removes the liquid carrier remaining on the transfer roller 121 together with the supplied cleaning liquid. A regulating element 125 is arranged at the outlet from the wet chamber. As shown in the figure, a retaining plate may be used as the adjustment element 125, and the retaining plate is disposed at an obtuse angle (for example, about 100 ° to 170 ° between the retaining plate and the exit surface) with respect to the transfer roller 121. This ensures that the liquid residue on the surface of the roller is substantially completely retained in the wet chamber and is shown via the cleaning liquid discharge path 124 ′ in order to separate it from the cleaning roller 124. Not supplied to the cleaning liquid storage container (next to the storage container 72).

  Instead of the retaining plate, a metering unit (not shown) including, for example, one or a plurality of metering rollers may be arranged at the position of the retaining plate. The metering roller has a predetermined interval with respect to the transfer roller 121, and removes an amount of the liquid carrier that causes a predetermined layer thickness on the downstream side of the metering roller based on the squeezing. At this time, the surface of the transfer roller 121 is not completely cleaned, and a liquid carrier having a predetermined layer thickness remains over the entire surface. The removed liquid carrier is returned to the cleaning liquid storage container via the cleaning roller 124.

  The cleaning roller 124 itself is mechanically kept clean by a doctor (not shown). The liquid containing toner particles removed in the cleaning is collected by the central collection container for all inks, cleaned and fed to the central cleaning liquid storage container for reuse.

  The counter roller 126 is similarly cleaned by the cleaning unit 127. As the cleaning unit 127, a doctor, a brush, and / or a roller remove dirt (paper dust, toner particle residue, liquid developer, and the like) from the opposing roller 126. The removed liquid is collected in a collection container 128, optionally cleaned and provided again to the printing process via a liquid discharge path 128 '.

  In the printing unit 11 that performs printing on the surface of the recording support 20, the facing roller 126 presses the non-printing surface (and therefore the surface that is still dry) of the recording support 20.

  Nevertheless, dust and / or paper dust or other dirt particles may already be present on the dry surface, which are later removed by the counter roller 126. In order to remove, the opposing roller 126 should be wider than the recording support 20. Accordingly, it is possible to satisfactorily remove stains outside the printing range.

  In the printing unit 12 that performs printing on the back surface of the recording support 20, the facing roller 126 directly presses the printed image 20 ′ with moisture that has not been fixed yet. In order to prevent the printed image 20 ′ from being removed by the counter roller 126, the surface of the counter roller 126 must have non-adhesive properties with respect to the toner particles and liquid carrier on the recording support 20.

  The development station 110 colors the potential printed image 20 'with a predetermined toner. In order to color, the developing roller 111 guides the toner particles toward the photoconductor. In order to color the developing roller 111 itself with an entire layer, first, a liquid having a predetermined concentration is supplied from a mixing container (not shown) to the storage chamber 112 via a liquid supply path 112 ′. Developer is supplied. From the storage chamber 112, the liquid developer overflows and is supplied to the pre-chamber 113 (a tank structure opened upward). An electrode segment 114 is disposed toward the developing roller 111, and the electrode segment 114 forms a gap between the electrode segment 114 itself and the developing roller 111.

  The developing roller 111 rotates through the pre-chamber 113 opened upward, and at this time, the liquid developer is received in the gap. Excess liquid developer is returned from the pre-chamber 113 to the storage chamber 112.

  Due to the electric field formed by the electric potential between the electrode segment 114 and the developing roller 111, the liquid developer is divided into two regions in the gap, which is also the first region of the layer near the developing roller 111 ( When the toner particles are concentrated in the first region (highly concentrated liquid developer)), the second region near the electrode segment 114 (the second region is diluted with respect to the toner particles (very low concentration). Liquid developer).

  Subsequently, the liquid developer layer is continuously conveyed to the metering roller 115. Since the metering roller 115 squeezes the upper layer of the liquid developer, the liquid developer having a specified layer thickness of about 5 μm remains on the developing roller 111 thereafter. Since the toner particles are present in the liquid developer mainly near the surface of the developing roller 111, the liquid developer located mainly outside is squeezed or retained and finally returned to the collection container 119. However, it is not supplied to the storage chamber 112.

  Therefore, the highly concentrated liquid developer is conveyed through the nip between the metering roller 115 and the developing roller 111. Thus, a uniform thickness layer of liquid developer having about 40 weight percent toner particles and about 60 weight percent liquid carrier is produced downstream of metering roller 115 (mass depending on printing process requirements). The ratio may vary somewhat). This uniform layer of liquid developer is conveyed to the nip between the developing roller 111 and the photoconductor drum 101. Therefore, the image area of the latent image is electrophoretically colored with toner particles, whereas the toner does not migrate to the photoconductor in the non-image area. A sufficient amount of liquid carrier is essential for electrophoresis. The liquid film separates on the downstream side of the nip on the basis of wetting at a substantially intermediate position, so that part of the layer remains attached to the surface of the photoconductor drum 101 and another part (mainly in the image area). The toner particles and the liquid carrier in the non-image area).

  In order to coat the developing roller 111 again with the liquid developer evenly under the same conditions, the remaining toner particles (this toner particle mainly forms a negative type non-transferred print image) and the liquid developer are cleaned. It is removed electrostatically and mechanically by a roller 117. The cleaning roller 117 itself is cleaned by the doctor 118. The removed liquid developer is supplied to the collection container 119 for reuse. The collection container 119 is also supplied with the liquid developer removed from the metering roller 115 by, for example, the doctor 116 and the liquid developer removed from the photoconductor drum 101 by the doctor 104.

  The liquid developer collected in the collection container 119 is supplied to the mixing container via the liquid discharge path 119 '. The mixing container is also supplied with fresh liquid developer and pure liquid carrier as needed. There must always be a sufficient amount of liquid carrier at the desired concentration (predetermined ratio of toner particles to liquid carrier) in the mixing container. Concentration is always measured in the mixing vessel and controlled accordingly in relation to the supply of the amount of liquid developer removed, the concentration of this liquid developer, and the amount and concentration of fresh liquid developer or liquid carrier. Is done.

  To control the concentration, the most concentrated liquid developer, pure liquid carrier, medium liquid (charge control agent and liquid carrier for controlling the charge of the toner particles) and removal from the corresponding storage container 72a The liquid developer thus prepared can be individually supplied to the mixing container.

In FIG. 3, one aspect of the development station is apparent. The liquid developer is supplied to the photoconductor drum 101 by this developing station. The illustrated embodiment starts from the development station 110 according to FIG. Accordingly, the same components are provided with the same reference numerals. The development station 110 according to FIG.
A development element, for example a development roller 111 or an endless development belt, which is arranged in contact with the photoconductor drum 101, the development roller 111 comprising an elastic coating having a predetermined conductivity;
A supply system 113, 114 having an electrode segment 114 and a pre-chamber 113; the supply system 113, 114 is connected to the developing roller 111 and the light in the rotational direction of the developing roller 111; The developing roller 111 is disposed on the upstream side (front side) of the contact zone with the conductive drum 101.
The cleaning unit 200 includes a cleaning roller 117 as a cleaning element, a doctor unit 201, and a supply unit 202. The supply unit 202 applies fluid to the doctor unit 201. The cleaning element (cleaning roller 117 or cleaning belt) is disposed in contact with the developing roller 111 and removes the residual liquid developer remaining on the developing roller 111 after the development of the electrostatic charge image from the developing roller 111. Thereafter, the residual liquid developer is scraped off from the cleaning roller 117 by the doctor unit 201, for example, the doctor 118 in FIG. 2, and in this case, the supply unit 202 is configured to remove the residual liquid developer from which the doctor unit 201 has been scraped off. Work to remain free from.
A metering means may optionally be provided, which may be configured as a metering roller 115 with a doctor 116 in some cases.

Each of the functional elements (for example, photoconductor drum 101, developing roller 111, electrode segment 114, cleaning roller 117, metering roller 115) is applied with a potential that varies depending on the polarity of the toner charge, which may be positive or negative. . The following definitions apply in the following description:
The potential 1 at the first functional element is higher than the potential 2 at the second functional element, which means a higher positive for positive toner polarity.
The potential 1 at the first functional element is higher than the potential 2 at the second functional element, which means a higher negative for negative toner polarity.

  The following description starts with a positive toner charge.

  The supply systems 113 and 114 convey the liquid developer toward the developing roller 111, and in this case, the amount of toner contained in the liquid developer is required for coloring the electrostatic image on the photoconductor drum 101. It is larger than the toner amount. The toner concentration in the supplied liquid developer is, for example, 3% to 30%, preferably 5% to 12%. The liquid developer can be metered between the metering roller 115 and the developing roller 111. In this case, the pressing force, hardness, and surface roughness of the developing roller 111 and the metering roller 115 determine the transport amount of the liquid developer that passes through the nip between the developing roller 111 and the metering roller 115, and thus light. The layer thickness of the liquid developer facing the conductor drum 101 is determined. In this case, the metering roller 115 always has a higher potential than the developing roller 111. This ensures that toner is not undesirably transferred to the metering roller 115. At the same time, the toner concentration in the liquid developer layer is increased, for example, from 20% to 60%, and an even toner distribution on the developing roller 111 is ensured. Thereafter, the adjusted liquid developer reaches the contact zone between the developing roller 111 and the photoconductor drum 101, where the electrostatic charge image is colored. The potentials of the developing roller 111 and the photoconductor drum 101 are selected so that the toner is transferred to the photoconductor drum 101 in the image area and the toner is not transferred to the photoconductor drum 101 in the non-image area. The liquid developer that remains on the developing roller 111 after the development of the printed image (hereinafter referred to as residual liquid developer) is subsequently removed from the developing roller 111 by the cleaning roller 117.

  In order to promote the transfer of toner from the developing roller 111 to the cleaning roller 117, the cleaning roller 117 is at a lower potential than the potential of the developing roller 111 in the case of positive toner charge. The resulting voltage difference between the developing roller 111 and the cleaning roller 117 is in the range of 10V to 2000V, preferably 50V to 300V.

  The doctor unit 201 is in contact with the cleaning roller 117, and the doctor unit 201 removes the residual liquid developer from the cleaning roller 117. The doctor means 201 comprises at least one doctor 203 (corresponding to the doctor 118 according to FIG. 2), which is in contact with the cleaning roller 117, so that the residual liquid developer is scraped off from the cleaning roller 117. It is. The doctor 203 is hereinafter referred to as a cleaning doctor 203 and is shown in FIGS.

  The cleaning doctor 203 in contact with the cleaning roller 117 is preferably adjusted to have no electric field with respect to the cleaning roller 117. Therefore, the cleaning doctor 203 is at the same potential as the cleaning roller 117, and in this case, power may be supplied from the same power supply network. As a result, the contact location of the cleaning doctor 203 with the cleaning roller 117 is non-potential, and no current flows through the contact location. Such a construction means ensures that no adhesion forces are generated between the cleaning doctor 203 and the cleaning roller 117 that cause wear.

  During the cleaning operation using the cleaning doctor 203, toner and toner components may pass through the cleaning gap between the doctor edge of the cleaning doctor 203 and the cleaning roller 117. In this case, the toner and toner components accumulate as fallen objects on the back side of the cleaning doctor 203. Problem arises. Deposition is seen especially when the doctor edge has a rough surface. As a result, the cleaning gap is widened by deposits so that residual liquid developer is no longer sufficiently scraped off by the cleaning doctor 203. In order to solve this problem, according to the present invention, as will be described later, the cleaning doctor 203 is cleaned with a fluid, for example, a liquid developer at least in the region of the doctor edge. In this case, the layer made of residual liquid developer existing on the cleaning roller 117 is completely removed by the cleaning doctor 203. The liquid developer thus scraped off can be led out to the collection container 119 (FIG. 2) via the doctor holder 204 (FIG. 6), for example. When the cleaning doctor 203 and the doctor holder 204 are configured to be smooth and are selectively further non-adherently covered, the residual liquid developer can be easily led out to the collection container 119.

  First, the cleaning unit 200 when using the doctor means 201 having only one doctor (cleaning doctor 203) will be described.

  In order to completely remove the residual liquid developer from the cleaning roller 117 and in addition to ensure a long service life of the cleaning doctor 203, the cleaning unit 200 provides a supply for fluid in addition to the cleaning doctor 203. Means 202, the supply means 202 directs fluid to the cleaning doctor 203, in particular at its doctor edge, at least in the region of the contact zone between the cleaning doctor 203 and the cleaning roller 117. The fluid is preferably a liquid developer that should be diluted with respect to the toner. In this case, the toner concentration of the residual liquid developer on the cleaning roller 117 is reduced in the contact zone with the cleaning roller 117, and as a result, the cohesive force between the toner particles in the residual liquid developer is reduced.

  An example of the supply means 202 can be seen from FIGS. 3 to 9 described below.

  In FIG. 3, the supply means 202 includes a flow guide element 205, for example, a flow passage, and the liquid developer is conveyed from the pre-chamber 113 toward the cleaning doctor 203 via the flow guide element 205. Since the flow guide element 205 can be connected to the overflow of the pre-chamber 113, excess liquid developer (this liquid developer is not transferred to the developing roller 111) is passed through the cleaning doctor 203 via the flow guide element 205. Guided towards. If the liquid developer is derived at a predetermined location in the pre-chamber 113 (where the liquid developer is diluted with respect to the toner by the transfer of toner to the developing roller 111), the low concentration liquid developer with respect to the toner Can be guided toward the cleaning doctor 203.

  When metering means 115, 116 are disposed on the developing roller 111, the liquid developer (this liquid developer has been removed from the developing roller 111 by the metering means 115, 116 and similarly diluted with respect to the toner) Then, it is sent to the flow guide element 205 through the collecting groove 206 and used for cleaning the cleaning doctor 203 (FIG. 3).

  When the supply unit 202 is disposed on the upper side of the cleaning doctor 203 (FIG. 3), the liquid developer can be directly guided to the cleaning doctor 203 without another constituent unit.

  Moreover, the supply means 202 may include a collection container 119 filled with a liquid developer. In this case, the liquid developer can be guided from the collection container 119 to the cleaning doctor 203. For this purpose, the cleaning unit 207 may be used as a supply means. The cleaning unit 207 may be combined with the flow guiding element 205 together with the supply means 202 described above.

  In the first aspect, the cleaning unit 207 may include a collection container 119 or a unique collection tank for liquid developer, and further includes a suction pipe 208 extending from within the collection container 119 and a suction unit 209 such as a flash. A pump (cleaning pump), a transport system 210, such as a distribution tube, and a distribution system 211, such as a cleaning nozzle, may be provided. The flash pump 209 is, for example, a diaphragm pump, and sucks the liquid developer from the collection container 119 via the suction pipe 208 and pumps the liquid developer to the cleaning nozzle 211. The cleaning nozzle 211 sprays the liquid developer onto the cleaning doctor 203, particularly the doctor edge. The cleaning nozzle 211 can be arranged with respect to the cleaning doctor 203 so that the cleaning nozzle 211 sprays the liquid developer onto the upper surface (FIG. 4) of the cleaning doctor 203 or the lower surface of the cleaning doctor 203 (FIG. 3). The liquid developer flowing down from the cleaning doctor 203 can be supplied to the collection container 119 again. The number of cleaning nozzles 211 is adapted to the width of the cleaning doctor 203, and for example, three cleaning nozzles 211 may be provided. The cleaning nozzle 211 may be configured as a wide jet nozzle.

  When the liquid developer is sprayed from above to the doctor edge of the cleaning doctor 203 by the cleaning unit 207 (FIG. 4), the residual liquid developer toner to be scraped off on the cleaning roller 117 is released. Easily washed away. When the cleaning unit 207 sprays the liquid developer onto the lower surface of the cleaning doctor 203 (FIG. 3), the toner residue that has not been removed from the cleaning roller 117 by the cleaning doctor 203 is washed away, and the toner residue on the cleaning roller 117 is removed. Deposition is avoided.

  The use of the cleaning unit 207 further has the advantage that the heat generated at the doctor site is derived by cleaning. The collection container 119 may be arranged in a circulation path, and the collection container 119 communicates with the mixing container 219 via the pump 218, and the mixing container 219 is connected to the pre-chamber 113 via the pump 220. In this case, the scraped liquid developer can be supplied to the mixing container 219, where it can be mixed with the supplied new liquid developer.

  In one refinement according to the invention (FIG. 5), a potential element 212 is arranged next to the flow guide element 205, for example at the height of the contact line of the cleaning doctor 203 / cleaning roller 117 from the cleaning roller 117. In this case, a positive potential larger than the potential of the cleaning roller 117 is applied to the potential element 212. Thereby, before the toner contacts the cleaning doctor 203, the adhesion force of the toner to the cleaning roller 117 can be reduced. By the action of the electric field, the toner in the liquid layer is lifted from the surface of the cleaning roller 117, and as a result, the stress (pressure) applied to the toner particles at the doctor position is reduced.

FIG. 6 shows an example of the doctor holder 204. A cleaning doctor 203 is fixed to the doctor holder 204. Since the doctor holder 204 is rotatably supported on the rotating shaft 2 13 , the cleaning doctor 203 can abut on the cleaning roller 117 by the rotation of the doctor holder 204. After the cleaning doctor 203 comes into contact with the cleaning roller 117, the doctor holder 204 is continuously moved to the stopper 214, for example, 0.2 mm to 1 mm, preferably 0.8 mm, so that the cleaning doctor 203 is raised. It contacts the cleaning roller 117 under a preload. During the initial cleaning operation, after a slight initial wear of about 50 μm has occurred in the cleaning doctor 203, a force balance between the doctor preload and the shearing force for cleaning occurs. There is no further wear on the cleaning doctor 203 and the doctor length of the cleaning doctor 203 remains unchanged.

In general, the following adjustment values are preferred for the cleaning unit 200 of FIGS.
The cleaning doctor 203 and the doctor holder 204 have a smooth surface, and optionally the cleaning doctor 203 and the doctor holder 204 may have a coating that is non-adherent to the liquid developer.
-Since the potentials of the cleaning doctor 203 and the cleaning roller 117 are the same, the contact portion of the cleaning roller 117 with respect to the cleaning doctor 203 has no potential, and no current flows through this contact portion.
The potential of the cleaning roller 117 is selected so that toner is attracted from the developing roller 111 to the cleaning roller. The potential difference is in the range of 10V to 2000V, preferably in the range of 50V to 300V.

  Another embodiment of the doctor means 201 is shown in FIGS. In FIG. 7 to FIG. 9, the doctor means 201 is realized by two doctors 215 and 216 arranged at the front and rear, and the doctor 215 and the doctor 216 together form a doctor chamber 217. The doctor that first contacts the cleaning roller 117 as viewed in the rotational direction of the cleaning roller 117 is the cleaning doctor 215, and the subsequent doctor is referred to as the shield doctor 216.

  The doctor chamber 217 is filled with a fluid, for example, a liquid developer, up to the cleaning roller 117. The cleaning doctor 215 has a role of scraping the residual liquid developer from the cleaning roller 117 as completely as possible. The shield 216 plays two roles, the shield 216 serves on the one hand to hold the fluid in the doctor chamber 217, and on the other hand the surface of the cleaning roller 117 is dried downstream (backward) of the shield 216. And work to make sure it is thoroughly cleaned.

  Due to the wetting inside the doctors 215 and 216 up to the contact zone between the cleaning roller 117 and the doctors 215 and 216 due to the fluid in the doctor chamber 217, accumulation of toner and toner components inside the doctors 215 and 216 can be avoided. As a result, no liquid developer residue is produced on the cleaning roller 117 downstream of the shield 216.

  FIGS. 7 to 9 show the arrangement of the three modes of the doctor means 201 including the cleaning doctor 215 and the shield doctor 216 with respect to the cleaning roller 117. In FIG. 7, the doctor means 201 is positioned with respect to the cleaning roller 117 such that both doctors 215 and 216 are pushed by the cleaning roller 117. In FIG. 8, the metering doctor 216 is pulled while the cleaning doctor 215 is pushed. In FIG. 9, the chamber doctor 201 is arranged in a posture rotated with respect to FIG. 7.

  The doctors 215 and 216 are attached to the doctor holder 204 in a form corresponding to FIG. A collection container 119 may be disposed below the doctor means 201.

  The introduction of the doctor chamber 217 prevents the formation of deposits at the doctor edges of the doctors 215 and 216 over a relatively long period. Even if a small breakage occurs on the doctor edges of the doctors 215 and 216, toner and toner components do not accumulate on the doctor edges. Thereby, the use period of the doctors 215 and 216 is extended. Furthermore, process variations can be allowed without causing problems during cleaning. Such process fluctuations include fluctuations in toner cohesion (for example, due to changes in service life, storage changes, production fluctuations), fluctuations in rolling resistance (particularly the developing roller 111), stress fluctuations (particularly in the case of cleaning stress), and toner concentration. It can be variable.

The coating of the cleaning roller 117 may be selected, for example, as follows:
The resistance may be from 0 to ^{10 10} ohm × cm;
The layer thickness may be 10 μm to 400 μm, preferably 50 μm to 200 μm.
The material may be metal (hard chromium, tungsten carbide, Hartcoat®; anodized film of aluminum) or ceramic (aluminum oxide, chromium oxide, titanium oxide or mixtures thereof).

In general, the development station 110 comprising the embodiment of the cleaning unit 200 according to the present invention has the following advantages:
1) The supply system 113, 114 realizes excessive conveyance of the toner supply amount to the developing roller 111. Therefore, the low-concentration liquid from the supply system 113, 114 to the cleaning zone between the cleaning roller 117 and the doctor unit 201 is realized. Since the supply of the developer is realized, in the cleaning zone, a reduction in toner density including the unraveling of the toner layer on the cleaning roller 117 is achieved.
2) The surface of the cleaning roller 117 may be manufactured to be smooth and wear resistant.
Leads to even removal of residual liquid developer from the developing roller 111;
A slight roughness of the cleaning roller surface leads to a slight adhesion of toner particles to the cleaning roller 117;
-Many toner particles or toner components do not reach under the doctor edge, leading to good scraping of the toner particles from the cleaning roller 117, which results in reduced toner stress.
3) The smooth and non-adhesive surfaces of the cleaning doctors 203 and 215 and the doctor edges of the cleaning doctors 203 and 215 are
・ Easier discharge of residual toner scraped off
Resulting in a constant circulation of toner, which is also a prerequisite for a stable toner concentration for the supply systems 113, 114.
4) By installing the doctor through the fixed stopper 214 for the doctor holder 204,
-Wear occurs only at the beginning of the service period of the new cleaning doctors 203, 215,
-Wear is limited to a few μm, which gives a long service life of the cleaning doctors 203, 215 (over 100h)
The wear occurs only on the cleaning doctors 203, 215, coupled with the smooth, wear-resistant surface of the cleaning roller 117;
• Equal contact of the cleaning doctors 203, 215 with the cleaning roller 117 is provided.
5) Toner stress in the cleaning zone is reduced, and stability is improved.
This is because cleaning of the cleaning doctors 203 and 215 reduces the residence time of the residual liquid developer in the vicinity of the contact position of the cleaning doctors 203 and 215 with respect to the cleaning roller 117.
This is because the dissolution of the residual liquid developer on the cleaning roller 117 by the potential element 212 reduces the interaction at the contact position of the cleaning doctors 203 and 215 with the cleaning roller 117.
6) To avoid toner accumulation on the cleaning doctor 203, the use of a wide nozzle in combination with the diaphragm pump 209 is
A high pressure can be formed when the cleaning doctor 203 is cleaned, and thus a high working efficiency can be achieved.
・ Enables a stable function without risk of drying. This is because a wide nozzle having a diameter larger than 1 mm that does not block can be used.
Allows the formation of a spray jet at an angle of 0 ° to 150 ° with respect to the flow direction. A compact structural form is thus achieved.
7) The suction of the liquid developer from the collection container 119 to avoid toner accumulation on the cleaning doctor 203 saves the use of the second liquid. In this case, the toner density control is not affected.
8) Combined with the excessive transport to the supply systems 113, 114, by the uniform return transport of the residual liquid developer to the collection container 119,
-Always, excess liquid developer can flow to the cleaning unit 200.
-Pumping back from the collection container 119 to the mixing container 219 can be performed intermittently.
9) The amount of toner that is not removed from the cleaning roller 117 by the cleaning doctor 203 is not increased by the cleaning of the cleaning doctor 203 (FIG. 3). This enhances the stability against process fluctuations and makes it possible to eliminate a damaged state in the event of a temporary failure of the toner concentration control device, for example.

  The photoconductor may preferably be configured in the form of a drum or endless belt. In this case, amorphous silicon may be used as a photoconductor material or an organic photoconductor material (also referred to as OPC).

  Instead of a photoconductor, another image carrier, such as a magnetic or ionizable image carrier, may be used, which does not operate on the photoelectric principle, Based on the principle, a latent image is formed on another image carrier in an electrical, magnetic or other manner, and the latent image is subsequently colored and finally transferred to the recording support 20.

  As the character generator 109, an LED line or a laser having a corresponding scanning mechanism may be used.

  Similarly, the transfer element may be formed as a roller or an endless belt. The transfer element may be omitted. In this case, the printed image 20 ′ is directly transferred from the photoconductor drum 101 to the recording support 20.

  The concept “electrophoresis” is understood as the movement of charged toner particles in a liquid carrier based on the action of an electric field. With each transfer of toner particles, the corresponding toner particles are transferred almost completely to another component. The liquid film is separated into about half after contact of both components based on the wetting of the components involved, so that about half remains attached to the first component and the remaining part is another component. It remains attached to the element. The printed image 20 ′ is transferred and then subsequently conveyed in the next part (component), thereby enabling the electrophoretic movement of the toner particles in the next transfer area as well.

  The digital printer 10 includes one or more printing units for front side printing and possibly one or more printing units for back side printing. The printing part may be arranged in a line shape (tandem type), in an L shape or in a U shape.

  Instead of the winding device 27, a post-processing device (not shown) such as a cutting machine, a folding machine, a binding machine or the like may be arranged on the downstream side of the pulling portion 26. Is brought into shape. For example, the recording support 20 may be processed so that a finally completed book is formed. The post-processing equipment may likewise be arranged in line or at an angle with respect to the tension part 26.

  The digital printer 10 may operate as a roll-to-roll printer as described above as a preferred embodiment. The recording support 20 may be cut into sheets at the end of printing, and then the sheets may be stacked or suitably post processed (roll to sheet printer). Similarly, the sheet-like recording support 20 may be supplied to the digital printer 10 to finally stack the sheets or perform subsequent processing (sheet-to-sheet printer).

  When printing is performed only on the surface of the recording support 20, at least one printing unit 11 of a predetermined color is required (simplex printing). When printing is also performed on the back side, at least one printing unit 12 for the back side is additionally required (duplex printing). In connection with the desired print images for the front and back surfaces, the printer arrangement comprises a corresponding number of print sections for the front and back surfaces, where each print section 11, 12 is always exclusively one color or one type. Designed for toner.

  The maximum number of printing sections 11, 12 is technically limited by the maximum mechanical tensile load and free tensile length of the recording support 20. Typically, any configuration from 1/0 configuration (only one print section for the surface to be printed) to 6/6 configuration is feasible. In the 6/6 configuration, six printing sections are provided for the front and back surfaces of the recording support 20 respectively. A preferred mode (configuration) is shown in FIG. 1 (4/4 configuration). In the configuration of FIG. 1, full-color printing is performed on the front and back surfaces using four primary colors. The order of the printing units 11 and 12 during four-color printing preferably proceeds from the printing units 11 and 12 that print light (yellow) to the printing units 11 and 12 that print dark colors, that is, for example, a recording support. No. 20 is printed from a light color to a dark color in the color order of YCMK.

  The recording support 20 may be manufactured from paper, metal, plastic, or other suitable printable material.

10 Digital printer 11, 11a to 11d Printing part (front side)
12, 12a-12d Printing part (back side)
20 Recording support 20 'Print image (toner)
20 '' transport direction of recording support 21 roll (entrance)
22 Feeding device 23 Adjustment unit 24 Reversing unit 25 Register unit 26 Pulling unit 27 Winding device 28 Roll (outlet)
30 fixing unit,
40 Air-Conditioning Module 50 Energy Supply Device 60 Controller 70 Liquid Management Module 71 Liquid Control Unit 72 Storage Container 100 Electrophotographic Station 101 Photoconductor Drum 102 Removal Light 103 Cleaning Device (Photoconductor)
104 Doctor (photoconductor)
105 Collection container (photoconductor)
105 'arrow 106 Charging device (Corotron)
106 'wire 106 "shield 107 introduction air passage (supply air)
108 Outlet air passage (exhaust)
109 Character generator 110 Developing station 111 Developing roller 112 Storage chamber 112 ′ Liquid supply path 113 Prechamber 114 Electrode segment 115 Metering roller (developing roller)
116 Doctor (metering roller)
117 Cleaning roller (developing roller)
118 Doctor (developing roller cleaning device)
119 Collection container (liquid developer)
119 ′ Liquid discharge path 120 Transfer station 121 Transfer roller 122 Cleaning unit (wet chamber)
123 Cleaning brush (wet chamber)
123 'Cleaning liquid supply path 124 Cleaning roller (wet chamber)
124 'Cleaning liquid discharge path 125 Adjustment element (retaining plate)
126 Counter roller 127 Cleaning unit (opposite roller)
128 Collection container (opposing roller)
128 'Liquid discharge path 129 Charging unit (Corotron provided on the transfer roller)
200 Cleaning unit 201 Doctor means 202 Supply means 203 Cleaning doctor 204 Doctor holder 205 Flow guide element 206 Collection groove 207 Cleaning unit 208 Suction pipe 209 Cleaning pump 210 Transport system 211 Cleaning nozzle 212 Potential element 213 Rotating shaft 214 Stopper 215 Cleaning doctor 216 Shield Kuta 217 Doctor chamber 218 Pump 219 Mixing container 220 Pump

Claims (8)

A digital printer (10) for printing on a recording support (20),
At least one station (100) for forming an electrostatic charge image of an image to be printed on the electrostatic charge image carrier (101), and coloring the electrostatic charge image on the electrostatic charge image carrier (101) using a liquid developer At least one printing station having at least one development station (110)
The development station (110)
A developing element (111), the developing element (111) coloring an electrostatic charge image on the electrostatic charge image carrier (101);
A supply system (113, 114) for applying a liquid developer to the developing element (111);
A cleaning element (117) for removing residual liquid developer remaining on the developing element (111) after development of the electrostatic charge image, a doctor means (201) in contact with the cleaning element (117), and a fluid for the cleaning A cleaning unit (200) having a supply means (202) that arrives at the doctor means (201) in the region of the contact zone between the element (117) and the doctor means (201),
A flow guide element (205, 206) is arranged as supply means (202) between the supply system (113, 114) and the doctor means (201), the flow guide element (205, 206); ) through the liquid developer is flow to the doctor means (201) as said fluid,
A collecting groove (206) is arranged as the flow guide element (206) between the metering means (115, 116) contacting the developing element (111) and the doctor means (201), Through the collection groove (206), the liquid developer removed from the developing element (111) by the metering means (115, 116) flows toward the doctor means (201),
The flow guide element (205) is provided to the supply system (113, 114) or the metering means (115, 116) so that the liquid developer diluted with respect to the toner flows toward the doctor means (201). Arranged,
A digital printer for printing on a recording support.   The flow guide element (205) is disposed as the supply means (202) between the overflow portion of the supply system (113, 114) for the liquid developer and the doctor means (201), 2. A digital printer according to claim 1, wherein the liquid developer flows to the doctor means (201) as the fluid via a flow guiding element (205). As the supply means (202), a cleaning unit (207) including at least one cleaning nozzle (211) is provided, and the cleaning nozzle (211) supplies the fluid from the upper side or the lower side to the doctor means ( blown to 201), according to claim 1 or 2 digital printer according. A digital printer according to any one of claims 1 to 3 , wherein the doctor means (201) and the cleaning element (117) are at the same potential. The doctor means (201) is fixed to a pivotally supported doctor holder (204), which preloads the doctor means (201) towards the cleaning element (117). multiplying the digital printer of any one of claims 1 to 4. A digital printer (10) for printing on a recording support (20),
At least one station (100) for forming an electrostatic charge image of an image to be printed on the electrostatic charge image carrier (101), and coloring the electrostatic charge image on the electrostatic charge image carrier (101) using a liquid developer At least one printing station having at least one development station (110)
The development station (110)
A developing element (111), the developing element (111) coloring an electrostatic charge image on the electrostatic charge image carrier (101);
A supply system (113, 114) for applying a liquid developer to the developing element (111);
A cleaning element (117) for removing residual liquid developer remaining on the developing element (111) after development of the electrostatic charge image, a doctor means (201) in contact with the cleaning element (117), and a fluid for the cleaning A cleaning unit (200) having a supply means (202) that arrives at the doctor means (201) in the region of the contact zone between the element (117) and the doctor means (201),
A flow guide element (205, 206) is arranged as supply means (202) between the supply system (113, 114) and the doctor means (201), the flow guide element (205, 206); ) Through which the liquid developer flows as the fluid to the doctor means (201),
The doctor means (201) includes a cleaning doctor (215) and a shield (216), and the cleaning doctor (215) and the shield (216) together form a doctor chamber (217). the doctor chamber 217, as the fluid wets the said cleaning element and (117) Dokutaejji, the fluid is filled with, wherein the digital printer for printing on record support. The digital printer according to claim 6 , wherein the cleaning doctor (215) and the shield doctor (216) abut against the cleaning element (117) so as to be pushed by the cleaning element (117). The cleaning doctor (215) and the shield doctor (216) are arranged such that the cleaning doctor (215) is pushed by the cleaning element (117) and the shield doctor (216) is pulled by the cleaning element (117). The digital printer according to claim 6 , wherein the digital printer abuts against the cleaning element.