Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G15/00—Apparatus for electrographic processes using a charge pattern
  • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
  • G03G15/10—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/015—Ink jet characterised by the jet generation process
  • B41J2/02—Ink jet characterised by the jet generation process generating a continuous ink jet
  • B41J2/035—Ink jet characterised by the jet generation process generating a continuous ink jet by electric or magnetic field
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G15/00—Apparatus for electrographic processes using a charge pattern
  • G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
  • G03G15/0142—Structure of complete machines
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G15/00—Apparatus for electrographic processes using a charge pattern
  • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
  • G03G15/10—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer
  • G03G15/104—Preparing, mixing, transporting or dispensing developer
  • G03G15/105—Detection or control means for the toner concentration

Definitions

• Continuous ink jet printing uses printheads that eject a continuous stream of individual ink drops.
• Some continuous inkjet printing systems use high-voltage electrodes in close proximity to the ejected ink drops to selectively deflect ink drops to electrostatically control which of the ink drops reach a print zone. In this way a desired image may be formed on a media in the print zone.
• controlling the electrodes requires complex and expensive hardware.
• Figure 1 is a simplified side view of a printing system according to one example
• Figure 2 is a simplified plan view of a printing system according to one example
• Figure 3 is a simplified side view of a portion of a printing system according to one example
• Figure 4 is a simplified block diagram of a printer controller according to one example
• Figure 5 is a flow diagram outlining a method of operating a printing system according to one example
• Figure 6 is a simplified side view of a printing system according to one example
• Figure 7 is a simplified side view of a portion of a printing system according to one example.
• Figure 8 is a simplified side view of a printing system according to one example
• Figure 9 is a simplified side view of a portion of a printing system according to one example
• Figure 10 is a simplified side view of a printing system according to one example
• Figure 1 1 is a simplified side view of a printing system according to one example
• Figure 12 is a simplified side view of a printing system according to one example.
• Figure 13 is a schematic view of a printing system according to one example.
• FIG. 1 there shown a simplified side view of a printing system 100 according to one example. A corresponding plan view is shown in Figure 2.
• the printing system 100 comprises an electrostatic imaging member 102 (generally shown as 102 in Figure 1 ) on which a latent electrostatic image is generated.
• the latent image comprises electrostatically charged and non- charged portions that represent an image to be printed.
• the printing system 100 is a single colour printing system, in which case the term 'latent image' represents the single colour image to be printed. As described further below, in a further example the printing system 100 is part of a colour printing system. In this case the term 'latent image' represents a single colour separation of an image to be printed.
• the electrostatic imaging member 102 is a photoconductor member 102.
• the photoconductor member 102 comprises a continuous photoconductor belt 104 that rotates about a pair of rollers 106. One or both of the rollers 106 may be powered to cause the photoconductor belt to rotate or revolve in a known manner.
• the photoconductor belt may be a photoconductor roller, cylinder, drum, or the like.
• the photoconductor member 102 has a surface that is able to hold an electrostatic charge and in which portions of the electrostatic charge may be dissipated in a controlled manner by shining light onto a portion of the photoconductor surface.
• the photoconductor member 102 may be a photoconductor member such as an organic photoconductor comprising a suitable doped organic material.
• a photoconductor member such as an organic photoconductor comprising a suitable doped organic material.
• Such photoconductors are widely used in known printing systems.
• such photoconductors are commonly used in liquid electro-photographic printing systems, such as in Hewlett-Packard Indigo digital printing presses.
• a charging module 108 applies a substantially uniform electrostatic charge on a portion or the whole of the photoconductor belt 104.
• the charging module 108 is a charging roller, although in other example other types of charge inducing mechanism may be used, for example such as a corona discharge module.
• the charging module 108 may apply a substantially uniform charge in the region of about +/-1000 V, although in other examples higher or lower levels of charge may be applied. In some examples a positive charge may be applied to the photoconductor belt 104, although in other examples a negative charge may be applied to the photoconductor belt 104.
• An imaging module 1 10 selectively dissipates electrical charges on the photoconductor belt 104 based on an image.
• the imaging module 1 10 may comprise a laser or light emitting diode (LED) imaging module that selectively shines light on the photoconductor belt 104 corresponding to an image to be printed to selectively dissipate electrical charges on the photoconductor belt 104. This leaves a latent image comprising charged and non-charged portions of the photoconductor belt 104 that represent the image to be printed.
• the printing system 100 further comprises a printhead receiver 1 1 1 for receiving a printhead 1 12 having an array of printhead nozzles 128 (shown in Figure 2) through each of which a stream of individual printing fluid drops may be ejected.
• the printhead receiver 1 1 1 may be any suitable mechanical and/or electrical interface into which a printhead 1 12 may be inserted. During operation, the printhead 1 12 may eject a continuous stream of printing fluid drops.
• the printing fluid may be any suitable printing fluid, such as an ink, or a post or pre-treatment printing fluid such as a primer or varnish.
• Printing fluid may be supplied to the print head 1 12 by a printing fluid supply system (not shown).
• the printing fluid supply system may be integral or external to the printhead 1 12.
• each printhead is supplied with a single type or colour of printing fluid, such as a single colour of printing ink.
• ink any suitable printing fluid including both ink and non- ink printing fluids.
• the stream of ink drops ejected from each printhead nozzle 128 comprises a continuous stream of individual ink drops.
• the printhead 1 12 ejects drops having a substantially constant velocity, a substantially constant volume, and a substantially constant drop rate.
• the continuous inkjet printhead 1 12 may eject drops at the rate of between about 50 000 to 200 000 drops per second.
• each drop may have a volume in the range of about 2 to 200 Pico litres.
• each ejected drop may have a speed in the range of about 2 to 40 m/s.
• the nozzles 128 are arranged to span across substantially the whole width of the photoconductor belt 104 and may be disposed in a single or in multiple printheads.
• the nozzles 128 may be arranged in a one-dimensional array. Ink drops ejected from each nozzle follow a path 1 14 downwards towards a first ink receiving zone 1 18.
• the first ink receiving zone is an ink collection zone in the form of an ink collector 1 18.
• the path 1 14 is a vertical or substantially vertical path. In other examples the path 1 14 may be an inclined path. Ink drops diverted to the ink collector 1 18 may be recycled and reused by the printhead 1 12.
• One portion, in this example an end portion, of the photoconductor belt 104 is arranged in proximity to the continuous ink jet printhead 1 12 such that the photoconductor belt 104 is in close proximity to the ink drop path 1 14.
• the zone in closest proximity to the ink drop path and the photoconductor belt 104 is referred to herein as an ink drop deflection zone 1 16.
• the printing fluid may be electrically charged by a printing fluid charging module (not shown).
• the charging is suitable performed before the printing fluid arrives in the printing fluid or ink deflection zone 1 16 and may, for example, be suitably performed before or after the ink or printing fluid is ejected from the printhead.
• ink drops are electrostatically deflected by charged portions of the photoconductor in the ink drop deflection zone 1 16 such that the deflected ink drops follow a second ink drop path 132 ( Figure 3) to a second ink receiving zone 130.
• the second ink receiving zone 130 is a print zone 130.
• ink drops deflected to the print zone 130 may create ink marks on a media 120 positioned in the print zone 130 to form a printed image as the media 120 is advanced through the print zone 130 by a media handling mechanism 126.
• the distance between the photoconductor belt 104 and the ink drop path 1 14 may be chosen based in part on the voltage of the electrical charge on the photoconductor belt 104. In one example, where the voltage of the electric charge applied to the photoconductor belt 104 is about 1000 V, the photoconductor belt 104 may be positioned at a distance of about 100 microns from the stream of ejected ink drops 1 14. In other examples other distances may be chosen.
• the printing system 100 is generally controlled by a printer controller 124. As shown in Figure 4, the controller 124 comprises a processor 402 such as a microprocessor, a microcontroller, a computer processor, or the like.
• the processor 402 is in communication with a memory 406 via a communication bus 404.
• the memory 406 stores computer implemented instructions 408 that, when executed by the processor 402 cause the controller 124 to operate the printing system 100 in accordance with the method described below and as illustrated in Figure 5.
• the controller 124 controls the printing system 100, and in particular the media handling system 126, to position a sheet or web of media in the print zone 130.
• the controller 124 controls the printhead 1 12 to start ejecting a stream of individual ink drops.
• the controller controls the printhead 1 12 to eject a stream of ink drops of a substantially constant volume, at a substantially constant speed, and at a substantially constant rate.
• the ejected ink drops are ejected into the ink collector 1 18.
• the controller 124 controls the photoconductor belt 104 to start rotating.
• the linear speed at which the controller 124 controls the photoconductor belt 124 to rotate at may be derived, at least in part, from the speed of the ejected ink drops and the separation between consecutive ejected drops.
• the controller 124 controls the charging module 108 to apply a uniform electrostatic charge along a portion of the photoconductor belt 104 in proximity to the charging module 108.
• the controller 124 controls the imaging module 1 10 to selectively dissipate electrical charges on the photoconductor belt 104, in accordance with an image to be printed, to generate a latent image on the photoconductor belt 104.
• the controller 124 controls the media handling mechanism 126 to advance the media 130 through the print zone 130 in synchronization with the latent image on the photoconductor belt 104. This may include, for example, starting to advance the media through the print zone 130 when the leading edge of the latent image on the photoconductor belt 104 arrives at a predetermined position in the ink drop deflection zone 1 16.
• the controller 124 controls the media handling mechanism 126 to advance the media 120 through the print zone 130 at the same linear speed at which the photoconductor belt is rotated.
• One advantage of using a latent electrostatic image on a photoconductor member to control the ejection paths of ink drops ejected from a continuous inkjet printhead is that the technology used to produce such latent images is tried and tested technology. For example, Hewlett-Packard's range of Indigo presses use such technology in their liquid electro-photographic (LEP) printing systems.
• LEP liquid electro-photographic
• a further advantage is that the examples described herein provide a simple way of controlling ink drops ejected from a wide array of printhead nozzles, thereby enabling continuous ink jet printing to be performed on wide media sizes, and with a high printing resolution.
• FIG. 6 there is a shown a printing system 600 according to a further example.
• the printhead 1 12 is arranged to eject ink drops in the print zone 130.
• An ink collector 602 is provided in close proximity to the path 1 14 of ejected ink drops such that electrostatic charges on the photoconductor belt 104 in the region of the ink deflection zone 1 16 cause the electrostatic deflection of ink drops to a path 702 and into the ink collector 602, as illustrated in Figure 7.
• deflected ink drops do not reach the print zone 130
• FIG. 8 there is shown a printing system 800 according to a yet further example.
• the printhead 1 12 is arranged to eject ink drops in the print zone 130.
• Electrostatic charges on the photoconductor belt 104 in the region of the ink deflection zone 1 16 cause the electrostatic deflection of ink drops to a path 902 and onto the photoconductor belt 104, as illustrated in Figure 9.
• ink drops which are not intended to be printed on a media are ejected on to the photoconductor belt 1 04.
• a photoconductor cleaning module 802 is provided to remove any ink on the photoconductor prior to a new latent image being generated thereon.
• the photoconductor member is provided in the form of a photoconductor drum 1002, for example with a photoconductor foil or layer attached to the outside of a drum.
• the printhead 1 12 is arranged to eject ink drops into an ink collector 1 18.
• a latent image of electrostatic charges is generated on the photoconductor drum 1002 in the manner described above.
• Electrostatic charges on the photoconductor drum 1002 in proximity to an ink drop deflection zone cause ink drops to be diverted into an ink receiving zone that forms a print zone on the surface of photoconductor drum 1002, as illustrated in Figure 1 1 to cause an image to be printed on the surface of the photoconductor drum 1002 as the photoconductor drum 1002 rotates.
• Ink drops of the photoconductor drum 1002 may then be transferred to a sheet or web of media 120 by feeding the media through a nip formed between the photoconductor drum 1002 and a transfer roller 1 10. The transfer of the image onto the media takes place through to the application of pressure between the media and the photoconductor drum 1002.
• a printing system 1200 is provided.
• the printing system 1000 of Figure 1 1 has an intermediate transfer member (ITM) 1202 onto which the image printed on the photoconductor drum 1002 is transferred.
• the transferred image on the ITM 1202 is then transferred to a media by feeding the media through a nip formed between the ITM 1202 and a transfer roller 1204.
• the transfer of the image onto the media takes place through the application of pressure between the media and the photoconductor drum 1002.
• the printing system 1300 comprises multiple printing stations 1302.
• Each printing station 1302 may be a printing system in accordance with one of the example printing systems described above.
• Each of the printing systems prints with a different colour ink.
• printing station 1302a may print with a cyan coloured ink
• printing station 1302b may print with a magenta coloured ink
• printing station 1302c may print with a yellow coloured ink
• printing station 1302d may print with a black coloured ink.
• more or less printing stations 1302 may be provided.
• the printing system 1300 is generally controlled by a controller 1304.
• the controller 1304 obtains an image to be printed and obtains, or generates, four separate images each representing a different colour separation corresponding to each of the four coloured printing stations 1302.
• the controller then controls each of the printing stations 1302 in the manner generally described above.
• the controller 1304 controls a media handling mechanism 1308 to advance a media 1306 through each printing station 1302 such that each of the different images representing different ones of the colour separations are printed on the media 1306, such that a full colour image is printed on the media 1306.
• the controller 1304 controls each of the printing stations 1302 and the media handling mechanism 1308 such that each of the colour separations is printed with a high degree of image separation registration accuracy.
• any such software may be stored in the form of volatile or non-volatile storage such as, for example, a storage device like a ROM, whether erasable or rewritable or not, or in the form of memory such as, for example, RAM, memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a CD, DVD, magnetic disk or magnetic tape.
• volatile or non-volatile storage such as, for example, a storage device like a ROM, whether erasable or rewritable or not
• memory such as, for example, RAM, memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a CD, DVD, magnetic disk or magnetic tape.
• the storage devices and storage media are examples of machine-readable storage that are suitable for storing a program or programs that, when executed, implement examples of the present invention.
• Examples of the present invention may be conveyed electronically via any medium such as a communication signal carried over a wired or wireless connection and examples suitably encompass the same. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Ink Jet (AREA)
• Particle Formation And Scattering Control In Inkjet Printers (AREA)

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• 2012
  • 2012-11-29 IN IN4007DEN2015 patent/IN2015DN04007A/en unknown
  • 2012-11-29 WO PCT/EP2012/073941 patent/WO2014082668A1/en not_active Ceased
  • 2012-11-29 BR BR112015012272-8A patent/BR112015012272B1/pt not_active IP Right Cessation
  • 2012-11-29 EP EP12797850.0A patent/EP2926200B1/en active Active
  • 2012-11-29 CN CN201280077364.9A patent/CN104854515B/zh not_active Expired - Fee Related
  • 2012-11-29 US US14/646,662 patent/US9387668B2/en active Active

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