EP0816944B1 - Vorrichtung zum direkten elektrostatischen Drucken (DEP) mit konstantem Abstand zwischen der Druckkopfstruktur und den Tonerzufuhrmitteln - Google Patents

Vorrichtung zum direkten elektrostatischen Drucken (DEP) mit konstantem Abstand zwischen der Druckkopfstruktur und den Tonerzufuhrmitteln Download PDF

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Publication number
EP0816944B1
EP0816944B1 EP19970201283 EP97201283A EP0816944B1 EP 0816944 B1 EP0816944 B1 EP 0816944B1 EP 19970201283 EP19970201283 EP 19970201283 EP 97201283 A EP97201283 A EP 97201283A EP 0816944 B1 EP0816944 B1 EP 0816944B1
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EP
European Patent Office
Prior art keywords
printhead structure
toner
delivery means
printing
toner delivery
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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EP19970201283
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English (en)
French (fr)
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EP0816944A1 (de
Inventor
Guido Desie
Günther Dieltjens
Ludovicus Joly
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Agfa Gevaert NV
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Agfa Gevaert NV
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Priority to EP19970201283 priority Critical patent/EP0816944B1/de
Priority to DE1997600075 priority patent/DE69700075T2/de
Publication of EP0816944A1 publication Critical patent/EP0816944A1/de
Priority to US09/064,559 priority patent/US6227655B1/en
Priority to JP12806498A priority patent/JPH10305609A/ja
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Publication of EP0816944B1 publication Critical patent/EP0816944B1/de
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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]
    • 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
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/34—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the powder image is formed directly on the recording material, e.g. by using a liquid toner
    • G03G15/344—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the powder image is formed directly on the recording material, e.g. by using a liquid toner by selectively transferring the powder to the recording medium, e.g. by using a LED array
    • G03G15/346—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the powder image is formed directly on the recording material, e.g. by using a liquid toner by selectively transferring the powder to the recording medium, e.g. by using a LED array by modulating the powder through holes or a slit
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2217/00—Details of electrographic processes using patterns other than charge patterns
    • G03G2217/0008—Process where toner image is produced by controlling which part of the toner should move to the image- carrying member
    • G03G2217/0025—Process where toner image is produced by controlling which part of the toner should move to the image- carrying member where the toner starts moving from behind the electrode array, e.g. a mask of holes

Definitions

  • This invention relates to a printing device useful in direct electrostatic printing (DEP).
  • DEP direct electrostatic printing
  • electrostatic printing is performed directly from a toner delivery means on a toner receiving member by means of an electronically addressable printhead structure.
  • the toner or developing material is deposited directly in an imagewise way on a receiving substrate, the latter not bearing any imagewise latent electrostatic image.
  • the substrate is an intermediate endless flexible belt (e.g. aluminium, polyimide etc.)
  • the imagewise deposited toner must be transferred onto another final substrate. If, however, the toner is deposited directly on the final receiving substrate, a possibility is fulfilled to create directly the image on the final receiving substrate, e.g. plain paper, transparency, etc. This deposition step is followed by a final fusing step.
  • the method makes the method different from classical electrography, in which a latent electrostatic image on a charge retentive surface is developed by a suitable material to make the latent image visible. Further on, either the powder image is fused directly to said charge retentive surface, which then results in a direct electrographic print, or the powder image is subsequently transferred to the final substrate and then fused to that medium. The latter process results in an indirect electrographic print.
  • the final substrate may be a transparent medium, opaque polymeric film, paper, etc.
  • DEP is also markedly different from electrophotography in which an additional step and additional member is introduced to create the latent electrostatic image. More specifically, a photoconductor is used and a charging/exposure cycle is necessary.
  • a DEP device is disclosed in e.g. US 3,689,935.
  • This document discloses an electrostatic line printer having a multi-layered particle modulator or printhead structure comprising :
  • Selected potentials are applied to each of the control electrodes while a fixed potential is applied to the shield electrode.
  • An overall applied propulsion field between a toner delivery means and a receiving member support projects charged toner particles through a row of apertures of the printhead structure.
  • the intensity of the particle stream is modulated according to the pattern of potentials applied to the control electrodes.
  • the modulated stream of charged particles impinges upon a receiving member substrate, interposed in the modulated particle stream.
  • the receiving member substrate is transported in a direction orthogonal to the printhead structure, to provide a line-by-line scan printing.
  • the shield electrode may face the toner delivery means and the control electrode may face the receiving member substrate.
  • a DC-field is applied between the printhead structure and a single back electrode on the receiving member support.
  • This propulsion field is responsible for the attraction of toner to the receiving member substrate that is placed between the printhead structure and the back electrode.
  • the printing device as described in the original Pressman patent is very sensitive to changes in distances from the toner application module towards said shield electrode, leading to changes in image density.
  • EP-A 675 417 it is disclosed to use a magnetic brush as toner delivery means, using a two-component developer (comprising toner and carrier particles), and to provide "long hairs" on said brush so that the hairs touch the printing structure.
  • a two-component developer comprising toner and carrier particles
  • the problem of varying image density, that can remain in a device according to EP-A 675 417, due to a varying distance between the surface of the magnetic brush and the printhead structure can further be decreased by adapting the electrical conductivity of the carrier particles used on the magnetic brush as described in European Application 96202815, filed on October 10, 1996.
  • a charged toner conveyer (a CTC), whereon the toner particles can be deposited by a magnetic brush or any other means known in the art, presents advantages. But the problem of uneven density (white banding) in a direction perpendicular to the printing direction has to be solved.
  • EP-A 740 224 a device is described in which the frequency of said density banding (in a direction perpendicular to the printing direction) due to the variation of the distance from the toner application module towards said printhead structure is diminished.
  • a drawback of this device is the difficulty of manufacturing such a printhead structure with the desired accuracy for high resolution printers (50 dpi (dot per inch) or 20 dots/cm) or higher.
  • a high resolution printer necessitates a printhead structure with small apertures and small spacing between the printing apertures, necessitating a very accurate positioning of the guiding members.
  • a guiding or spacer means is placed before the printing apertures over the full length.
  • JP-A 08/300715 a printhead structure with "guiding means” is disclosed, wherein the guiding means are placed before the printing apertures and form an angle with the direction of movement of the toner delivery means. Again at least one guiding means per printing aperture is provided. Thus also in this device a very accurate positioning of the guiding members is required, which complicates the manufacture of the printhead structure.
  • DEP printing devices wherein the distance between the toner delivery means and the printhead structure is kept constant, wherein the toner particles are not subjected to excessive shear and that is relatively simple to manufacture.
  • a DEP device comprising a printhead structure having a first and a second major face, and a toner delivery means having an external surface wherein
  • said constant distance D is such that 25 ⁇ m ⁇ D ⁇ 500 ⁇ m.
  • Fig. 1 shows a schematic view, viewed from the outer surface of the toner delivery means, of a printhead structure according to this invention.
  • Fig. 2 shows a schematic sectional view of a printhead structure according to this invention, mounted in contact with a toner delivery means.
  • Fig. 3 shows a schematic view, viewed from the outer surface of the toner delivery means, of a further embodiment of a printhead structure according to this invention.
  • toner delivery means is used as that part of the device that brings toner particles in the vicinity of the printhead structure.
  • the spacing means in a device according to this invention, were advantageously constructed such that the distance D between the printhead structure and the toner delivery means was between 25 and 500 ⁇ m, more preferably between 50 and 300 ⁇ m.
  • the advantage of the larger distance D (in e.g. US 5,448,272 it is said that a distance D of one toner diameter is enough) is not only a substantial prevention of toner smearing by shearing forces exerted on the toner and of the clogging of the printing apertures, but also that the device can be operated with more than 1 layer of toner particles on the surface of the toner delivery means.
  • the AC-field in a device according to this invention, has preferably a frequency between 1 and 5 kHz and can have a sinusoidal, square or triangular shape, it can be a symmetrical as well as an asymmetrical signal.
  • this AC-field can be applied on the sleeve of the toner delivery means, when the DC-voltage on the sleeve of the toner delivery means is 0 (i.e. the sleeve is grounded) as well as when the DC-voltage on the sleeve has either a positive or a negative value.
  • the root mean square voltage (V rms ) of the AC-field superimposed on the DC-field between printhead structure and toner delivery means preferably relates to the voltage of the DC-field. More preferably the root means square voltage of the AC-field (V rms )is preferably at least 10 times higher than the voltage of the DC-field on which it is superimposed.
  • V rms the voltage of the DC-field on the sleeve is zero (i.e. when the sleeve is grounded) and an AC-field is applied, then
  • ⁇ , which is the upper limit for the ratio
  • the ratio of AC/DC is taken as an absolute value, (
  • the spacing means in a device according to this invention can have different shapes, it can be a row of dots, a row of bars, a bar, they can be rectangular, cylindrical, triangular, etc as long as they perform the effect of keeping the distance between the printhead structure and the toner delivery means constant.
  • the spacing means can be made of any material, although spacing means made of insulating material, e.g. polymeric material, ceramic material, are largely preferred.
  • the insulating material can preferably be a flexible polymeric material as e.g. a polyester, a polyimide, a polyamide, a polyurethane, a polycarbonate, etc.
  • the face of the spacing means contacting the outer surface of the toner delivery means can be provided with a friction reducing layer for aiding the smooth gliding of the face of the spacing means over the surface of the toner delivery means.
  • a friction reducing layer can comprise a solid lubricant dispersed in a binder, e.g. disulfide of molybdenum dispersed in a binder, as disclosed in US 5,497,175, the layer can be made with a perfluorpolymer (e.g. TEFLON (tradename), the friction reducing layer can comprise matting agents protruding above the layer, which diminish the surface of the spacing means contacting the surface of the toner delivery means.
  • Such spacing particles can advantageously comprise a lubricant (e.g. a wax) as described in EP-A 241 600 or comprise fluor-containing compounds.
  • the spacing means used in a device according to this invention can be permanently attached to the face of the printhead structure facing the external surface of the toner delivery means or can be placed between said face of the printhead structure and the surface of the toner delivery means. In the latter case the spacing particles are kept in place by pressing the toner delivery means against the spacing means that are pressed against the printhead structure.
  • the printhead structure is preferably kept in contact with the surface of the toner delivery means via the spacing means, permanently mounted on the printhead structure or simply interposed between the printhead structure and the outer surface of the toner delivery means, by resilient means.
  • the printhead structure comprises a resilient substrate, e.g. a polymeric sheet material, being between 50 and 400 ⁇ m thick, wherein printing apertures are present the contact of the printhead structure with the toner delivery means, via the spacing means, can be assured by the own resilience of the printhead structure.
  • Suitable material to be used as polymeric sheet material, with a certain resilience, in a printhead structure useful in this invention are e.g. polyester, polyimide, polyamide, polyurethane, polycarbonate, etc.
  • the resilient means keeping the printhead structure and the toner delivery means in contact via the spacing means can be springs, coil springs, rubber bands, etc.
  • Fig. 1 shows a schematic view, viewed from the outer surface of the toner delivery means, of a printhead structure according to this invention.
  • the printhead structure (100) comprises an array of printing apertures (101) located between two spacing means (102).
  • the spacing means are positioned over a distance (d) apart.
  • F l The sum of these forces will be referred to as F l .
  • F w In the direction perpendicular to the array of printing apertures (herein after termed the width of the printhead structure), forces f w1 , f w2 , f w3 , f w4 , f w5 and f w6 are exerted on the printhead structure.
  • the sum of these forces will be referred to as F w .
  • the forces f w2 and f w5 are exerted between the spacing means, and the sum of them will be referred to as F wb .
  • F wo Forces f w1 , f w3 , f w4 and f w6 are exerted outside the spacing means, and the sum of them will be referred to as F wo .
  • the values of F l and F w are related to the distance whereover they act on the printhead structure and are thus expressed in N/m.
  • F l (f l1 + f l2 + f l3 + f l4 )/n .
  • the forces, acting on the printhead structure are in figure 1 shown as being exactly parallel or exactly perpendicular to the direction of the printing apertures.
  • the resilient means exerting said forces can, in a DEP device according to this invention, be placed in a position deviating from the exact parallel or exact perpendicular position.
  • the printing quality with a device according to the present invention could further be ameliorated when the forces exerted on the printhead structure by the resilient means were adapted to each other.
  • the printing quality was found to be ameliorated when F w /F l ⁇ 0.5, , and substantially ameliorated when F w /F l ⁇ 0.25.
  • F w was adapted to the distance d between the spacing means, such that F w /d ⁇ 5000, the printing quality was further enhanced. Further improvement of the printing quality could be observed when F wb /F wo ⁇ 1.00.
  • the printhead structure is mounted in contact, via the spacer means, with the toner delivery means in such a way that the part of the printhead structure being in contact, via the spacer means, with the toner delivery means has a kind of a bulge extending between 0.2 and 20 mm above the line connecting the surface of supporting means for the printhead structure, that faces the printhead structure, preferably between 1 and 5 mm (both limits included).
  • a schematic view of a printhead structure according to thus invention combined with a toner delivery means is given in fig 2.
  • the numerical 104 denotes means for supporting the printhead structure 100 and 103 denotes the toner delivery means, the driving means for said toner delivery means and the supporting means to support the toner delivery means in the DEP device are not shown.
  • Arrows f w3 and f w4 denote forces exerted on the printhead structure in the length of this printhead structure and are thus part of F w .
  • the printhead structure 100 is pressed against the toner delivery means 103 by the forces f w3 and f w4 over spacing means 102. A portion of spacing means 102 shown by a dotted line, to show the printing apertures 101 in the printhead structure.
  • the distance between the line 105 connecting the surfaces of the supporting means 104 and the printing apertures (b in fig. 2) is the kind of bulge describe immediately above.
  • the height of the bulge (b) is preferably such that 0.2 ⁇ b ⁇ 20 mm, more preferably such that 1 ⁇ b ⁇ 5 mm.
  • a printhead structure according to this invention can be made in various forms : the printhead structure can carry one array of printing apertures (throughout this document, an "array of printing aperture” is used to indicate at least one row of printing apertures) between spacing means. It can carry a plurality of arrays of printing apertures, each of said arrays being located between two spacing means and the arrays being staggered.
  • FIG. 3 such a printhead structure is schematically shown : Two arrays of printing apertures (101a, 101b) are located adjacent to each other and each is located between two spacing means (102a, 102b and 102c) spacing means 102b being common to the two arrays of apertures.
  • a third array of printing apertures (101c) between two spacing means (102d and 102e) is located in a staggered way with respect to the first two arrays of printing apertures.
  • the spacing means are located at a given distance of each other (d, d' and d''). In figure 3 d, d' and d'' are shown as being equal, but this is not necessarily so.
  • Any printhead carrying a plurality of arrays of printing apertures, said arrays having equal or different numbers of printing apertures, each of said arrays being located between two spacing means and the arrays being staggered, is within the scope of the invention.
  • a printhead structure with more than three arrays of printing apertures, that are equal or different in length, that comprise the same or a different number of rows of printing apertures and wherein the spacing means are equally or differently spaced is a printhead structure according to this invention.
  • a printhead structure useful in the present invention can also be a mesh shaped type of printhead structure as disclosed in e.g. US 5,036,341.
  • a printhead structure for use in a device according to this invention comprises a sheet of isolating material, preferably a polymeric material, wherein printing apertures are present.
  • the toner flow form the toner delivery means to the receiving substrate in a DC-field between said toner delivery means and said substrate is controlled by control electrodes on the printhead structure.
  • control electrodes Various forms of control electrodes are possible, there can be a control electrode around every printing aperture, a single control electrode can control a row of printing apertures, as disclosed in e.g.
  • a printhead structure used in this invention can comprise a shield electrode on the face of the printhead structure opposite to the face carrying the control electrodes.
  • a shield electrode can have various forms, it can be a continuous electrode, or it can have a form adapted to the printing apertures, as disclosed in European Application 96201622, filed on June 11, 1996.
  • the DC-field between the toner delivery means and the toner receiving substrate can be provided by applying a potential difference between said toner delivery means and a back electrode positioned behind said substrate, or it can be provided by applying a potential difference between said toner delivery means and said substrate itself as disclosed in European Application 96202228, filed on August 8, 1996.
  • the toner delivery means in a DEP device is a means comprising an endless outer surface for carrying charged toner particles. It may be cylindrical or can have the form of an endless belt.
  • the charged toner particles can originate from a magnetic mono-component developer. In that case it is beneficial that the toner delivery means comprise a magnetic field for attracting the charged toner particles to its surface.
  • the toner delivery means is an applicator using non-magnetic mono-component developer, i.e. the surface of the toner delivery means carries non-magnetic charged toner particles.
  • the charged toner particles on the surface of the toner delivery means originate from a multi- (two-)component developer comprising magnetic carrier particles and non-magnetic charged toner particles, then the toner particles are deposited from a magnetic brush (wherein both carrier and charged toner particles are present) on the toner delivery means, whereon only charged toner particles are present.
  • DEP devices using a magnetic brush carrying magnetic carrier particles and non-magnetic charged toner particles for bringing charged toner particles on to the toner delivery means are described in e.g. EP-A 740 224.
  • the toner delivery means is a magnetic brush comprising magnetic carrier particles and non-magnetic toner particles and the toner particles are directly extracted from the "hairs" of the magnetic brush.
  • the spacing means contact the sleeve of the magnetic brush and keep the distance between the magnetic brush and the printhead structure constant.
  • the width of the toner layer (or of the layer of hairs of the magnetic brush) applied to the toner delivery means is smaller than or equal to the distance between the spacing means at the end of the array of printing apertures.
  • the printhead structure The printhead structure.
  • a printhead structure was made from a polyimide film of 50 ⁇ m thickness, double sided coated with a 5 ⁇ m thick copper film.
  • a rectangular control electrode was arranged around each rectangular aperture.
  • Each of said control electrodes was connected over 2 M ⁇ resistors to a HV 507 (trade name) high voltage switching IC, commercially available through Supertex, USA, that was powered from a high voltage power supply.
  • a common shield electrode was present on the front side of the printhead structure, facing the toner delivery means.
  • the printhead structure had two rows of apertures.
  • the apertures had an aperture size of 360 ⁇ m x 120 ⁇ m
  • the size of the copper control electrodes was 520 ⁇ m x 280 ⁇ m.
  • the rows of apertures were staggered to obtain an overall resolution of 85 dpi.
  • the printhead structure comprised a shield electrode, having a slit of 1.6 mm wide, the printing apertures being located in said slit. This is a shield electrode and a printhead structure according to the disclosures in European Application 96201622 filed on June 11, 1996.
  • the printhead structure comprised two strips of polyurethane as spacing means. The spacing means were 300 ⁇ m thick and 10 mm wide and were placed at a distance (d) of 0.165 m.
  • the toner delivery means The toner delivery means
  • the toner delivery means was a commercially available toner cartridge comprising non magnetic mono component developer, the COLOR LASER TONER CARTRIDGE MAGENTA (M3760GIA), for the COLOR LASER WRITER (Tradenames of Apple Computer, USA).
  • the printhead structure and the charged toner conveyer were mounted in a frame and the printhead structure was stretched in said frame by spring coils and pressed against said charged toner conveyer, via the spacing means.
  • the distance between the charged toner conveyer and the printhead structure was 300 ⁇ m, i.e. the thickness of the spacing means.
  • the printhead structure was mounted in contact, via the spacer means, with the toner delivery means in such a way that the part of the printhead structure being in contact with the toner delivery means has a kind of a bulge extending 1 mm above the line connecting the surface of supporting means for the printhead structure.
  • a back electrode was present behind the paper whereon the printing proceeded, the distance between the back electrode and the back side of the printhead structure (i.e.
  • the printing quality of the printing examples below was visually judged on two criteria and given a quality figure from 5, very good to 1, bad.
  • the two criteria were evenness of density in the printing direction (EPD) and evenness of density in a direction perpendicular to the printing direction (EPPD).
  • a total printing quality (TQ) was given as (EPD + EPPD)/2.
  • 2.5.
  • the distance, d, between the spacing means was 0.165 m.
  • 2.5.
  • the distance, d, between the spacing means was 0.165 m.
  • 2.5.
  • the distance, d, between the spacing means was 0.165 m.
  • Example 3 was repeated, except for the DC and AC-field.
  • a DC-field of - 30 V was applied to the sleeve of the toner delivery means and an AC voltage of 1000 V (V rms ).
  • 30.3.
  • a printhead structure as described above, was mounted on a four frame bar, as described in EP-A 712 056, with four points of application for F l , acting over 50 mm and giving a force per linear m of 2000 N/m and with six points of application for F w , acting over 200 mm, and giving a force per linear m of 750 N/m.
  • On the outer surface of the toner delivery means a DC-field of-100 V was applied and an AC-field of 300 V rms superimposed to said DC-field.
  • 3.0.
  • the toner delivery means was arranged at 300 ⁇ m of the printhead structure and NO spacing means were present. I.e. the printhead structure and the toner delivery means made NO contact at all. Nr F w /F l F w /d

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)

Claims (10)

  1. DEP-Vorrichtung, das eine Druckkopfkonstruktion (100) mit einer ersten und einer zweiten großen Fläche und ein Tonerzuliefermittel (103) mit einer Außenfläche enthält, wobei
    i) die erste große Fläche der Druckkopfkonstruktion der Außenfläche des Tonerzuliefermittels zugewandt ist, und
    ii) die Außenfläche in eine Richtung A, bezogen auf die erste große Oberfläche, bewegt und durch wenigstens zwei Abstandhaltermittel (102), die mit der Richtung A einen Winkel zwischen 45° und 0° bilden, in einer konstanten Entfernung D von der ersten großen Fläche gehalten werden, dadurch gekennzeichnet, dass die Abstandhaltermittel in einer derartigen Entfernung d voneinander angeordnet werden, dass 1 cm ≤ d ≤ 50 cm.
  2. DEP-Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass die Abstandhaltermittel in einer derartigen Entfernung d voneinander angeordnet werden, dass 5 cm ≤ d ≤ 35 cm.
  3. DEP-Vorrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die konstante Entfernung D derartig ist, dass 25 µm ≤ D ≤ 500 µm.
  4. DEP-Vorrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die konstante Entfernung D derartig ist, dass 50 µm ≤ D ≤ 500 µm.
  5. DEP-Vorrichtung nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, dass die Druckkopfkonstruktion ein polymeres Substrat, in dem Drucköffnungen vorliegen, enthält.
  6. DEP-Vorrichtung nach Anspruch 5, dadurch gekennzeichnet, dass die Druckkopfkonstruktion eine große Anzahl Matrices von Drucköffnungen (101a, 101b, 101c) aufweist, jede Matrix zwischen zwei Abstandhaltermitteln (102a-102e) angeordnet wird und die Matrices versetzt angeordnet werden.
  7. DEP-Vorrichtung nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, dass die Druckkopfkonstruktion und das Tonerzuliefermittel über die Abstandhaltermittel durch federnde Mittel miteinander in Berührung gehalten werden.
  8. DEP-Vorrichtung nach Anspruch 7, dadurch gekennzeichnet, dass die federnden Mittel eine Kraft (Fℓ) in Richtung parallel zu den Drucköffnungen und eine Kraft (FW) in Richtung senkrecht zu den Drucköffnungen auf die Druckkopfkonstruktion ausüben, und dadurch gekennzeichnet, dass FW/Fℓ ≤ 0,5.
  9. DEP-Vorrichtung nach Anspruch 8, dadurch gekennzeichnet, dass FW/d < 5000.
  10. DEP-Vorrichtung nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, dass eine Wechselstromspannung WS eine an die Außenfläche der Tonerzuliefermittel angelegte Gleichspannung GS überlagert, und dadurch gekennzeichnet, dass 10 ≤ |WS/GS| ≤ ∞.
EP19970201283 1997-04-09 1997-04-29 Vorrichtung zum direkten elektrostatischen Drucken (DEP) mit konstantem Abstand zwischen der Druckkopfstruktur und den Tonerzufuhrmitteln Expired - Lifetime EP0816944B1 (de)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP19970201283 EP0816944B1 (de) 1997-04-29 1997-04-29 Vorrichtung zum direkten elektrostatischen Drucken (DEP) mit konstantem Abstand zwischen der Druckkopfstruktur und den Tonerzufuhrmitteln
DE1997600075 DE69700075T2 (de) 1997-04-29 1997-04-29 Vorrichtung zum direkten elektrostatischen Drucken (DEP) mit konstantem Abstand zwischen der Druckkopfstruktur und den Tonerzufuhrmitteln
US09/064,559 US6227655B1 (en) 1997-04-09 1998-04-22 DEP (direct electrostatic printing) device maintaining a constant distance between printhead structure and toner delivery means
JP12806498A JPH10305609A (ja) 1997-04-29 1998-04-23 直接静電印刷装置

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19970201283 EP0816944B1 (de) 1997-04-29 1997-04-29 Vorrichtung zum direkten elektrostatischen Drucken (DEP) mit konstantem Abstand zwischen der Druckkopfstruktur und den Tonerzufuhrmitteln

Publications (2)

Publication Number Publication Date
EP0816944A1 EP0816944A1 (de) 1998-01-07
EP0816944B1 true EP0816944B1 (de) 1998-12-23

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EP19970201283 Expired - Lifetime EP0816944B1 (de) 1997-04-09 1997-04-29 Vorrichtung zum direkten elektrostatischen Drucken (DEP) mit konstantem Abstand zwischen der Druckkopfstruktur und den Tonerzufuhrmitteln

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EP (1) EP0816944B1 (de)
JP (1) JPH10305609A (de)
DE (1) DE69700075T2 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6406132B1 (en) 1996-03-12 2002-06-18 Array Printers Ab Printing apparatus of toner jet type having an electrically screened matrix unit

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11240195A (ja) * 1997-12-22 1999-09-07 Minolta Co Ltd 直接印刷装置
EP0965455A1 (de) 1998-06-15 1999-12-22 Array Printers Ab Verfahren und Gerät für direktes elektrostatisches Drucken
EP1065574A1 (de) * 1999-06-29 2001-01-03 Agfa-Gevaert N.V. Vorrichtung für direktes elektrostatisches Drucken mit einem Zwischenbildträger und einem Druckkopf mit konstanten Abstand mit diesem Zwischenbildträger
EP1111478A1 (de) * 1999-12-20 2001-06-27 Agfa-Gevaert N.V. Vorrichtung zum direkten, elektrostatischen Drucken, wobei der Abstand zwischen dem Druckkopf und der geladenen Toner-Oberfläche konstant gehalten wird

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5552814A (en) * 1992-09-01 1996-09-03 Brother Kogyo Kabushiki Kaisha Image recording apparatus wherein toner carrier member and particle-flow modulating electrode member are held in contact with each other
JPH06255161A (ja) * 1993-03-02 1994-09-13 Brother Ind Ltd 記録装置
JPH06336049A (ja) * 1993-05-31 1994-12-06 Brother Ind Ltd 画像形成装置
JP3417625B2 (ja) * 1993-11-04 2003-06-16 ブラザー工業株式会社 画像形成装置
US5666147A (en) * 1994-03-08 1997-09-09 Array Printers Ab Method for dynamically positioning a control electrode array in a direct electrostatic printing device
EP0712056B1 (de) * 1994-11-08 1999-08-04 Agfa-Gevaert N.V. Vorrichtung zum direkten elektrostatischen Drucken mit speziellem Druckkopf

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6406132B1 (en) 1996-03-12 2002-06-18 Array Printers Ab Printing apparatus of toner jet type having an electrically screened matrix unit

Also Published As

Publication number Publication date
JPH10305609A (ja) 1998-11-17
EP0816944A1 (de) 1998-01-07
DE69700075D1 (de) 1999-02-04
DE69700075T2 (de) 1999-07-15

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