WO1996006740A1 - Tete d'impression electrostatique a electrodes de commande multiplexees et circuits d'attaque integres - Google Patents

Tete d'impression electrostatique a electrodes de commande multiplexees et circuits d'attaque integres Download PDF

Info

Publication number
WO1996006740A1
WO1996006740A1 PCT/IB1995/000765 IB9500765W WO9606740A1 WO 1996006740 A1 WO1996006740 A1 WO 1996006740A1 IB 9500765 W IB9500765 W IB 9500765W WO 9606740 A1 WO9606740 A1 WO 9606740A1
Authority
WO
WIPO (PCT)
Prior art keywords
printhead
electrodes
electrostatic
substrate
apertures
Prior art date
Application number
PCT/IB1995/000765
Other languages
English (en)
Inventor
Ove Larson
Original Assignee
Array Printers Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Array Printers Ab filed Critical Array Printers Ab
Publication of WO1996006740A1 publication Critical patent/WO1996006740A1/fr

Links

Classifications

    • 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
    • B41J2/385—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective supply of electric current or selective application of magnetism to a printing or impression-transfer material
    • B41J2/41—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective supply of electric current or selective application of magnetism to a printing or impression-transfer material for electrostatic printing
    • B41J2/415—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective supply of electric current or selective application of magnetism to a printing or impression-transfer material for electrostatic printing by passing charged particles through a hole or a slit
    • B41J2/4155—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective supply of electric current or selective application of magnetism to a printing or impression-transfer material for electrostatic printing by passing charged particles through a hole or a slit for direct electrostatic printing [DEP]

Definitions

  • the invention relates to electrographical printing devices, and in particular to an improved direct electrostatic printhead utilizing an integrated, multiplexed matrix of control electrodes and drive circuits.
  • Another type of electrostatic printing deposits pigmented particles, such as toner, directly on an information carrier to form a visible image.
  • this method of printing uses electrostatic fields controlled by addressable electrodes for allowing passage of pigment particles through selected apertures in a printhead structure.
  • a separate electrostatic field is provided to attract the pigment particles to an imaging substrate in image configuration.
  • Many of the methods used in field imaging, i.e. creating an electric field pattern in the print zone), such as particle charging, particle transport, and particle fusing are similar to those used in "laser printers".
  • the novel feature of direct printing is its simplicity of simultaneous field imaging and particle transport to produce a visible image directly on the information carrier.
  • U.S. Patent No. 3,689,935 granted to Pressman discloses a method to produce text and pictures with pigment particles on an information carrier directly from computer generated signals, without the need for those signals to be intermediately converted to another form of energy such as light energy, as is required in electrographic printers like laser printers.
  • Pressman discloses an electrostatic line printer incorporating a multilayered particle modulator or printhead comprising a layer of insulating material, a continuous layer of conducting material on one side of the insulating layer and a segmented layer of conducting material on the other side of the insulating layer. At least one row of apertures is formed through the multilayered particle modulator. Each segment of the segmented layer of the conductive material is formed around a portion of an aperture and is insulated from every other segment of the segmented conductive layer. Selected potentials are applied to each of the segments of the segmented conductive layer while a fixed potential is applied to the continuous conductive layer. An overall applied field projects charged particles from a particle source through the row of apertures.
  • the density of the particle stream is modulated according to the pattern of potentials applied to the segments of the segmented conductive layer.
  • the modulated stream of charged particles impinge upon a print-receiving medium interposed in the modulated particle stream and translated relative to the particle modulator to provide line-by-line scan printing.
  • a drawback to the Pressman device is that the particle source must be an airborne stream of charged particles. That stream of airborne particles is of low particle density, resulting in very poor contrast on the print-receiving medium. In addition, it is very difficult to effectively control the airborne particle stream.
  • the Larson '341 patent discloses a method which begins with a stream of electronic signals defining the image information. A uniform electric field is created between a high potential on the back electrode and a low (0 volt) potential on the developer sleeve. That uniform field pattern is modified by potentials on addressable wires in a two-dimensional wire mesh array placed in the print zone.
  • the wire mesh array consists of parallel control wires, each of which is connected to an individual voltage source, across the width of the paper surface.
  • the multiple wire electrodes are aligned in adjacent pairs parallel to the motion of paper; the orthogonal wires called transverse electrodes are aligned perpendicular to the paper motion. All wires are initially at a V w (white) potential, preventing all toner transport from the developer sleeve. As image locations on the paper surface pass beneath wire intersections, adjacent transverse and print wire pairs are set to a V b (black) potential to produce an electrostatic field drawing the toner particles from the developer sleeve. The toner particles are pulled through the apertures being formed in the square region between four crossed wires (i.e. two adjacent rows and two adjacent columns), and deposited on a paper surface in the desired visible image pattern. The toner particle image is then made permanent by heat and pressure fusing the toner particles to the surface of the paper.
  • one voltage source can affect a plurality of apertures by multiplexing the electrode array, thereby reducing the number of drive circuits needed for the printhead. For example, in a device with M rows and N columns, the number of electronic drive circuits is reduced from M*N to M + N.
  • a drawback in the device of the Larson '341 patent is that during operation of the control electrode matrix, the individual wires can be sensitive to opening or closing of adjacent apertures. This cross-coupling results in undesired printing due to the thin wire border between apertures.
  • the woven wire mesh alternates the row and column electrode distance within each aperture so that the electrode matrix, as a whole, behaves as if all of the electrodes are substantially at a uniform distance from the particle carrier.
  • a two-layer control electrode circuit does not perform well because the layer closest to the particle carrier dominates in controlling the opening and closing of apertures.
  • the control electric fields acting between the control electrode matrix and the particle carrier are very sensitive to the distance between the control electrode matrix surface and the particle carrier surface. If the rows and columns are at different distances, as with layered circuit boards, their ability to accurately control the electric fields is greatly reduced. A single layer control electrode matrix would be more effective in controlling the apertures.
  • the present invention reduces the size, cost and complexity of electrostatic printers and the like, and furthermore makes advantageous use of materials and integrated circuit fabrication techniques to make an improved electrostatic printhead.
  • the electrode matrix is arranged for electrostatic control of charged particle passage through the apertures by application of at least one electrostatic potential to at least one control electrode.
  • At least one electronic decoder circuit and at least one control potential source is attached directly to the substrate and electrically connected to the electrode matrix for the addressable application of control potentials.
  • a significant reduction in size and complexity is achieved when the electronic circuits comprise, at least in part, integrated circuit dies which are attached directly to the substrate and electrically connected to the control electrode matrix.
  • a further improvement in print operation may be achieved by applying a conductive film over a portion of the control electrode surface, which reduces charge accumulation.
  • a preferred form for the electrode matrix comprises multiplexing the electrode array to reduce the number of decoder and drive circuits.
  • a passive multiplexing network involving for example, resistive or capacitive components, will allow addressable access to an MxN array of electrodes with only M + N galvanic connections.
  • a further reduction in size may be achieved by fabricating at least a portion of the electronic circuits directly on the insulating substrate as integrated circuits.
  • a preferred embodiment for such integration would entail the use of a crystalline silicon wafer for the printhead substrate, upon which is fabricated at least a portion of the electronic circuits.
  • the formation of precision apertures through a (OOD-oriented silicon wafer may be accomplished by means of an anisotropic etchant.
  • a printhead for electrostatic printing comprises a solid membrane defining at least one electrically insulating surface and having a plurality of apertures disposed therethrough.
  • a plurality of addressable electrodes is disposed on the insulating surface, each substantially adjacent to an aperture on the surface, and each galvanically isolated from the others.
  • At least one electronic decoder and drive circuit is attached to the membrane and is electrically connected to the addressable electrodes.
  • the addressable electrodes of the printhead are preferably located near a donor of charged particles such that the charged particles undergo an electrostatic interaction with said addressable electrodes.
  • the membrane may comprise an insulating, flexible material, such as polyimide foil, upon which conductive electrode material is laminated or otherwise deposited.
  • the membrane may comprise a rigid, insulating material such as alumina, upon which the electrode material is deposited, thereby achieving greater reliability.
  • a rigid substrate material offers the possibility of fabricating integrated electronic circuits directly on the printhead surface.
  • a crystalline silicon wafer may be used for the substrate of a high precision printhead, utilizing fabrication techniques in the integrated circuit arts.
  • Figure 1a is a schematic perspective of one embodiment of the invention.
  • Figure 1 b is an enlarged view of the control electrode matrix with surrounding means in Figure 1a.
  • Figure 2 is a sectional view through the print zone of Figure 1.
  • Figure 3 is a plan view of the central portion of one embodiment of a preferred electrostatic printhead.
  • Figure 4 is a sectional view through the print zone of a preferred electrostatic printhead.
  • Figure 5 is a plan view of the central portion one embodiment of a preferred electrostatic printhead.
  • Figure 6a is a plan view of a square aperture etched in a rigid silicon substrate.
  • Figure 6b is a sectional view through the etched square aperture of Figure 6a.
  • an electrostatic printer using a preferred embodiment of the invention comprises a container 1 for pigment particles 2, and which presents a mounting surface for the printhead 20.
  • a particle carrier such as a developing roller 4 is disposed within container 1 , and may enclose a multiple magnetic core 5 for attracting magnetic pigment particles 2 toward development roller 4.
  • Alternative means may as well be employed for attaching toner particles 2 to development roller 4, such as electrostatic attraction.
  • the printhead 20 is comprised of a control electrode matrix 3 with electrode leads 7 and electronic drive circuits 1 1. In operation, the printhead 20 is positioned relative to the development roller
  • control electrode matrix 3 is maintained in addressable potentiostatic cooperation with back electrode 9 and a segment of development roller 4 passing thereby.
  • a printhead substrate 6 supports control electrode matrix 3, which is comprised of an array of individual control electrodes 15, each preferably circumscribing an aperture 10 passing therethrough.
  • the control electrodes 15 and apertures 10 should be arranged such that the geometric projection of their location on a given print line should provide continuous and uniform coverage. They may, for example, be arranged in a skewed row and column configuration as described in Larson '144.
  • the present invention is not limited to a specific arrangement of apertures and control electrodes, nor to the profile of the aperture itself.
  • An information medium 8, usually paper, is preferably positioned adjacent to back electrode 9 for printing thereon and is advanced in a preset direction, defined here by arrow 22.
  • Coded control voltage signals from a remote source are supplied to electronic drive circuit 1 1 through external connector 16, and are subsequently decoded and distributed to drive the individual control electrodes 15 ( Figure 1 b).
  • the application of control potentials to an electrode 15 creates electric fields that partially open or close apertures 10 to passage of toner particles 2.
  • a visible image pattern is produced on information carrier 8 corresponding to the pattern of the control voltage signals.
  • control electrode matrix 3 is comprised of substrate 6 upon which is laminated or deposited a conductive layer making up etched electrodes 15 and electrode leads 7.
  • Control electrode matrix 3 is shown with one control electrode in the print condition where pigment particles 2 pass through one aperture 10a to information medium 8.
  • the information medium 8 may pass between control electrode matrix 3 and development roller 4. In this case, electric fields generated by control electrode matrix 3 permit or restrict toner 2 transport from development roller 4 onto information medium 8, without passage through aperture 10.
  • FIG 3 A preferred embodiment of an electrostatic printhead 20 is shown in figure 3, which displays a portion of a control electrode matrix 3 with attached electronic decoder and drive circuits 1 1.
  • Substrate 6 may be a thin, flexible insulating foil, such as polyimide about 25 ⁇ m thick, upon which is laminated or otherwise deposited a conductive layer, such as copper.
  • the conductive layer is etched or otherwise formed to define conductive leads 7 and electrodes 15 of control electrode matrix 3.
  • An insulating layer 12, shown in figures 2 and 4 is applied over the circuit traces 7.
  • Surface conductivity treatment 14 is applied over insulating layer 12, to both sides of the control electrode matrix 3 prior to attachment of the electronic dies.
  • the conductive coatings 14 function to avoid charge buildup on the substrate during operation of the printer.
  • Apertures 10 for passage of pigment particles though substrate 6 are typically about 150 ⁇ m in diameter, and may be formed by means of focused laser energy.
  • Electronic decoder and drive circuit dies 1 1 are attached to the substrate preferably by means of adhesive bonding.
  • Conductive traces 7 may be connected to the appropriate terminals of the die 1 1 by conductive wires 13, attached by wire bonding.
  • a central feature of the invention is integration of electronic decoder and drive circuits 1 1 with the control electrode matrix 3. In doing so, the numerous electrical connections 7 between the decoder and drive circuits 1 1 and the electrode matrix 3 may be fabricated using integrated circuit methods, thereby eliminating numerous bulky and potentially unreliable connectors.
  • control electrode array 3 may be multiplexed by "passive" component means, where passive herein characterizes a component which itself cannot function as a source of power.
  • passive component means may, for example, be a resistor- capacitor grid, where each node comprises a parallel resistor-capacitor combination with respective component values R m and C Cons.
  • the network functions to substantially add the voltages, V m + V n , at a node for characteristic times within about R ⁇ C,
  • An example of such an RC multiplexing network is disclosed in United States Patent 4,353,080, by D.A. Cross, and is herein incorporated by reference.
  • the integrated electronic decoder circuit 1 1 may be a serial- to-parallel converter, which accepts logic-level inputs and has a voltage output suitable for driving control electrode matrix 3.
  • the commercially available Supertex, Inc. model # HV31 may be used for the present embodiment.
  • the aforementioned features not only reduce the size, cost and complexity of direct electrostatic printheads, but increases their robustness and reliability by substantially reducing the size and number of connections to the printhead.
  • connectors between the decoder and drive circuit 1 1 and the electrode array 3 are substantially eliminated, while external connectors 16 to the printhead 20 itself will provide encoded electrical signals over far fewer electrical contacts.
  • the invention further facilitates printhead 20 maintenance and reliability by providing simultaneous or single-step replacement of both the control electrode array 3 and the decoder/drive circuits.
  • FIG. 1 Another preferred embodiment of the printhead 20 makes use of a rigid ceramic material, such as alumina, for substrate 6, as shown in figure 4.
  • Conductive traces 7 are etched from a solid layer of conductive material deposited, for example, by well known vacuum evaporation techniques.
  • an insulating layer 12 is applied over the circuit traces 7.
  • surface conductivity treatment 14 is applied to both sides of the control electrode matrix 3 prior to circuit attachment.
  • the conductive coatings 14 function to avoid charge buildup on the substrate during operation of the printer.
  • Apertures 10 for passage of pigment particles therethrough preferably have a diameter at least equal to the material thickness and may be formed by focused laser energy.
  • Electronic circuit dies 1 1 are attached to the substrate preferably using adhesive bonding.
  • Conductive traces 7 are attached to the appropriate terminals of the die with conductive wires 13 which may be secured by wire bonding.
  • electronic circuit dies 1 1 way be mounted in a packaging medium, such as a ceramic substrate or housing having interconnects between the package and die 11.
  • the packages are subsequently mounted to the substrate 6 by such processes as ball-grid array bounding or flip- clip solder bounding.
  • Still another preferred form of the printhead 20 makes use of crystalline silicon for substrate 6, as shown in figure 5.
  • Conductive traces 7 are deposited on the silicon substrate by well known integrated circuit fabrication techniques.
  • An insulating layer 12 is applied over the circuit traces as shown previously in Figure 4.
  • Surface conductivity treatment 14 is applied to both sides of the control electrode matrix 3 over the insulating layer 12.
  • the conductive coatings function to avoid charge buildup on the substrate during operation of the printer.
  • Apertures 10 for passage of pigment particles are preferably drilled through the substrate 6 by laser energy.
  • electronic decoder and drive circuits 1 1 may be formed directly into the substrate, as for example in the form of monolithic or thin film devices, thereby eliminating the separate assembly steps of die placement, adhesive bonding and wire bonding.
  • a preferred method for creating apertures 10 in a silicon substrate 6 comprises an anisotropic etching process, such as disclosed in "The Fabrication of High Precision Nozzles by the Anisotropic Etching of (100) Silicon” (Bassous, E, Baran, E.F., J. Electroche . Soc.: Sol. St. Sci. Techno!., vol. 125, no. 8, 1978, pp. 1321-1327) and incorporated herein by reference.
  • An array of substantially square apertures 10 may be fabricated by use of an anisotropic etchant acting on a single crystal (001 )-oriented silicon wafer.
  • the etch rate depends strongly on crystal lographic direction, being preferably much larger in the ⁇ 001 > direction than ⁇ 1 1 1 > direction.
  • the equilibrium shape of etch holes takes the basic form of a truncated pyramidal cavity bounded by the top and bottom surface planes of the substrate as shown in Figure 6b.
  • the size and shape of the cavities further depends on the geometry of the exposure mask, the duration of etching, and the wafer thickness. In perfect single crystal silicon, the angle between (001) and (1 1 1) planes is 57.54 degrees, defining a preferred equilibrium contour.

Abstract

Une tête d'impression électrostatique (20), qui comprend un ensemble adressable d'électrodes de commande (15) et des circuits électroniques (11) de décodage et d'attaque, permet de commander le dépôt direct de particules chargées (2) sur un support d'informations (8). Intégrer ces circuits (11) de décodage et d'attaque directement sur la tête d'impression permet de réduire nettement le nombre de connexions électriques, et donc les dimensions et la complexité de cette tête, tout en améliorant sa fiabilité. Multiplexer l'ensemble d'électrodes permet de réduire nettement le nombre de composants électroniques nécessaire à l'adressage de chaque électrode de commande (15), d'où une réduction supplémentaire de coût et de complexité. Une tête d'impression électrostatique de haute précision (20), fabriquée en silicium cristallin, facilite l'incorporation de composants électroniques intégrés.
PCT/IB1995/000765 1994-08-30 1995-08-30 Tete d'impression electrostatique a electrodes de commande multiplexees et circuits d'attaque integres WO1996006740A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US29812594A 1994-08-30 1994-08-30
US08/298,125 1994-08-30

Publications (1)

Publication Number Publication Date
WO1996006740A1 true WO1996006740A1 (fr) 1996-03-07

Family

ID=23149162

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB1995/000765 WO1996006740A1 (fr) 1994-08-30 1995-08-30 Tete d'impression electrostatique a electrodes de commande multiplexees et circuits d'attaque integres

Country Status (1)

Country Link
WO (1) WO1996006740A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002002340A1 (fr) * 2000-07-06 2002-01-10 Array Ab Appareil de formation d'image et procede

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5121144A (en) * 1990-01-03 1992-06-09 Array Printers Ab Method to eliminate cross coupling between blackness points at printers and a device to perform the method
US5204696A (en) * 1991-12-16 1993-04-20 Xerox Corporation Ceramic printhead for direct electrostatic printing

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5121144A (en) * 1990-01-03 1992-06-09 Array Printers Ab Method to eliminate cross coupling between blackness points at printers and a device to perform the method
US5204696A (en) * 1991-12-16 1993-04-20 Xerox Corporation Ceramic printhead for direct electrostatic printing

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
BASSOUS AND BARAN: "the fabrication of high precision nozzles by the anisotropic etching of (100) silicon", IBM THOMAS WATSON RESEARCH CENTER, vol. 125, no. 8, NEW YORK, pages 1321 - 1327 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002002340A1 (fr) * 2000-07-06 2002-01-10 Array Ab Appareil de formation d'image et procede

Similar Documents

Publication Publication Date Title
US5515084A (en) Method for non-impact printing utilizing a multiplexed matrix of controlled electrode units and device to perform method
US5274401A (en) Electrostatic printhead
US5402158A (en) Method for improving the printing quality and repetition accuracy of electrographic printers and a device for accomplishing the method
JP2790545B2 (ja) エレクトログラフィック・プリンタに於ける黒点間のクロスカップリングの除去装置
EP0476030B1 (fr) Procede d'amelioration de la qualite d'impression et de la precision de repetition d'imprimantes electrographiques et dispositif de mise en oeuvre du procede
US4748464A (en) Image-forming element for an electrostatic printer having electrodes in the form of a grid
US5315324A (en) High precision charge imaging cartridge
US5604522A (en) Ink jet head and a method of manufacturing the ink jet head
US4777500A (en) Electrostatic color printer
EP0712055B1 (fr) Dispositif de formation d'images
WO1996006740A1 (fr) Tete d'impression electrostatique a electrodes de commande multiplexees et circuits d'attaque integres
EP0753412B1 (fr) Imprimante de projection de toner avec structure d'électrodes de commande améliorée
US5340617A (en) Electrostatic patterning of multi-layer module lamina
EP0813969B1 (fr) Méthode de fabrication d'une tête d'enregistrement pour un dispositif d'enregistrement à jet d'encre
US5966152A (en) Flexible support apparatus for dynamically positioning control units in a printhead structure for direct electrostatic printing
EP0963852B1 (fr) Méthode d'impression et contrôle pour une tête d'impression avec électrodes de déviation pour l'impression électrostatique directe
JP3741781B2 (ja) 静電装置
EP0844095A2 (fr) Imprimante de projection de toner
US6330015B1 (en) Thick film thermal head
EP0983858B1 (fr) Méthode d'impression et contrôle pour une tête d'impression avec système d'électrodes de déviation pour l'impression électrostatique directe
JPH0725057A (ja) 静電印刷装置
EP0963853B1 (fr) Méthode d'impression dans un appareil d'impression électrostatique directe ayant une structure de tête d'impression avec électrodes de déflexion et moyens de contrôle électrique pour cettes électrodes de déflexion
EP0667565A2 (fr) Appareil et procédé de génération de motifs sur un substrat diélectrique
WO2000030858A1 (fr) Procede d'impression directe avec fonction de commande amelioree
JPH09193441A (ja) 粉体飛翔式記録用印字ヘッド

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): DE JP

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642