EP1093033A1 - Verfahren zum direkten elektrostatischen Ducken mit Tonerteilchen modifizierter Aufladungseigenschaften - Google Patents

Verfahren zum direkten elektrostatischen Ducken mit Tonerteilchen modifizierter Aufladungseigenschaften Download PDF

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Publication number
EP1093033A1
EP1093033A1 EP99203349A EP99203349A EP1093033A1 EP 1093033 A1 EP1093033 A1 EP 1093033A1 EP 99203349 A EP99203349 A EP 99203349A EP 99203349 A EP99203349 A EP 99203349A EP 1093033 A1 EP1093033 A1 EP 1093033A1
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EP
European Patent Office
Prior art keywords
toner particles
charge
toner
printing
group
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EP99203349A
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English (en)
French (fr)
Inventor
Guido c/o Agfa-Gevaert N.V. IIE 3800 Desie
Lode c/o Agfa-Gevaert N.V. IIE 3800 Deprez
Michel c/o Agfa-Gevaert N.V. IIE 3800 Vervoort
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Agfa Gevaert NV
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Agfa Gevaert NV
Agfa Gevaert AG
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Priority to EP99203349A priority Critical patent/EP1093033A1/de
Publication of EP1093033A1 publication Critical patent/EP1093033A1/de
Withdrawn legal-status Critical Current

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/097—Plasticisers; Charge controlling agents
    • G03G9/09733—Organic compounds
    • G03G9/09758—Organic compounds comprising a heterocyclic ring
    • 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

Definitions

  • This invention relates to a recording method and an apparatus for use in the process of Direct Electrostatic Printing (DEP), in which an image is created upon a receiving substrate by creating a flow of toner particles from a toner bearing surface to the image receiving substrate and image-wise modulating the flow of toner particles by means of an electronically addressable printhead structure.
  • DEP Direct Electrostatic Printing
  • toner particles are deposited directly in an image-wise way on a receiving substrate, the latter not bearing any image-wise latent electrostatic image.
  • a DEP device is disclosed in e.g. US-A-3 689 935 .
  • This document discloses an electrostatic line printer having a multi-layered particle modulator or printhead structure comprising :
  • Each control electrode is formed around one aperture and is isolated from each other control electrode.
  • Selected electric 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 support for a toner receiving substrate 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 substrate, interposed in the modulated particle stream.
  • the receiving substrate is transported in a direction perpendicular to the printhead structure, to provide a line-by-line scan printing.
  • the shield electrode may face the toner delivery means and the control electrodes may face the receiving substrate.
  • a DC-field is applied between the printhead structure and a single back electrode on the receiving substrate. This propulsion field is responsible for the attraction of toner to the receiving substrate that is placed between the printhead structure and the back electrode.
  • One of the problems with this type of printing devices is that charged toner particles can accumulate upon the printhead structure and in the printing apertures. Due to this problem the achievable printing density does not remain constant in the time, while the charged toner particles accumulated on the printhead structure may change the electrical field wherein the charged toner particles are propelled towards the substrate and the toner particles accumulated in the printing apertures can physically block the toner passage.
  • WST Wrong Sign Toner
  • CTC Charged toner conveyer
  • An other way to avoid the presence of wrong signed toner is to use a magnetic brush with two-component developer in which the toner particles are charged to a high charge-to-mass ratio ( ⁇ C/g) for bringing charged toner particles to the surface of the CTC.
  • ⁇ C/g charge-to-mass ratio
  • a high charge-to-mass ratio leads to a high sticking force of charged particles to electrode surfaces of opposite polarity so that printing at high speed with sufficient density becomes problematic. It is, e.g. indicated in EP-A-811 894 that a higher charge-to-mass ratio can also lead to an unevenness in image parts of maximum and moderate density.
  • charged toner particles are only applied once to the surface of said charged toner conveyor, and as a result the charge to mass ratio of the charged toner particles can't be enhanced by multiple contacts with carrier hairs touching said charged toner particles multiple times before they are propelled through said printhead apertures. Since the charge to mass ratio is not increasing as a function of printing time, the resulting printing density is not decreasing as a function of printing time. However, said charged toner particles may not be damaged by the recuperation process and have to be recycled, making the system complex and expensive.
  • a further object of the invention is to provide an inexpensive DEP device that can print at high speed with low clogging of the printing apertures and with high and constant maximum density over a long period of time.
  • the object of the invention is realised by providing a method for Direct Electrostatic Printing (DEP) comprising the steps of :
  • both a charge control agent (CCA) and a charge limitation agent (CLA) are incorporated in said toner particles.
  • Figure 1 shows schematically a DEP device according to the present invention using toner particles comprising a charge control agent (CCA) and a charge limitation agent (CLA) in a magnetic brush applying said charged toner particles to a charged toner conveyor.
  • CCA charge control agent
  • CLA charge limitation agent
  • toner accumulation on the printhead structure and in the printing apertures can partially or completely block said printing apertures, leading to white stripes of missing dots.
  • Adherence of toner particles can be avoided by using charged toner particles having a high charge to mass ratio and a low population of wrong sign toner (WST), i.e. toner particles having a polarity that is opposite to the polarity of most of the charged toner particles.
  • WST wrong sign toner
  • said expensive recuperation means (and resulting partially toner destruction) can be avoided, by using a toner that is adapted in charging kinetics and charging limits, so that after 30 seconds of printing the average charge to mass reaches a value of Q2/m, said value after 1 hour of printing changing by a factor of not more than 1.400.
  • said value changes by a factor of not more than 1.300
  • DEP devices wherein charged toner particles are loaded on a CTC via a toner dispensing part of a non-magnetic development system held at a distance of the CTC, wherein charged toner particles are loaded on a CTC via a toner dispensing part of a non-magnetic development system held in contact with the CTC, and devices wherein charged toner particles are loaded on a CTC via a magnetic brush containing magnetic carrier particles and non-magnetic carrier particles can all beneficially be operated in a method according to this invention using toner particles with adapted charging properties. It is especially beneficial to operate DEP devices, wherein charged toner particles are loaded on a CTC via a magnetic brush containing magnetic carrier particles and non-magnetic carrier particles, in a method according to this invention using toner particles with adapted charging properties.
  • Said toner particles are adapted via incorporation of charge control agents (CCA) to obtain very fast charging kinetics, while their charge to mass ratio is limited to a certain value by incorporation of charge limitation agents (CLA).
  • CCA charge control agents
  • CLA charge limitation agents
  • the combination of charge control agents (CCA) and charge limitation agents (CLA) provide very useful properties: i.e. the toner particles are charged very rapidly to a minimum charge to mass ratio, and after transfer of said toner particles to the charged toner conveyor a layer of charged toner particles is provided with sufficient charge to mass ratio, so as to prevent toner adhesion to said printhead structure as a result of wrong sign toner or toner with a much too small charge to mass ratio.
  • the toner particles with adapted charging properties for use in the method of this invention can further incorporate any ingredient known in the art, e.g., toner resin, a colorant, metal oxides, etc..
  • the toner particles with adapted charging properties for use in the method of this invention can be toner particles with a negative charge as well as toner particles with a positive charge.
  • charge control agents for inducing or enhancing a negative chargeability are used.
  • Charge control agents are well known in the art of preparation of toner particles, for toner particles with positive charge, mainly ammonium compounds, pyridinium compounds, triphenylmethane, cationic dyes, negrosine dyes, etc. are used.
  • Charge control agents for positive charging are commercially available through e.g. Ciba-Geigy of Switserland under trade name CG 14-146, CG 16-569, BASF of Germany under trade name NEPTUNSCHWARZ X60, Orient Chemical of Japan under trade name BONTRON P51, etc.
  • Charge control agents for negative charging are commercially available through e.g.
  • NCS LP 2145 NCS VP 2145
  • COPY CHARGE NCA Orient Chemical of Japan under trade name BONTRON E82, BONTRON S34, BONTRON S44, BONTRON F21, etc.
  • the charge limitation agent (CLA) used for adapting the charging properties of toner particles used in the method of this invention are meso-ionic compounds.
  • Meso-ionic compounds as referred to in the present invention are a group of compounds defined by W. Baker and W.D. Ollis as "5-or 6-membered heterocyclic compounds which cannot be represented satisfactorily by any one covalent or polar structure and possesses a sextet of p-electrons in association with the atoms comprising the ring.
  • the ring bears a fractional positive charge balanced by a corresponding negative charge located on a covalently attached atom or group of atoms" as described in Quart. Rev., Vol. 11, p. 15 (1957) and Advances in Heterocyclic Chemistry, Vol. 19, P. 4 (1976).
  • Preferred meso-ionic compounds are those represented by formula (I): wherein M represents a 5- or 6-membered heterocyclic ring composed of at least one member selected from the group consisting of a carbon atom, an oxygen atom, a sulphur atom and a selenium atom; and A - represents -O - , -S - or -N - -R, wherein R represents an alkyl group (preferably having 1 to 6 carbon atoms), a cycloalkyl group (preferably having 3 to 6 carbon atoms), an alkenyl group (preferably having 2 to 6 carbon atoms) an alkynyl group (preferably having 2 to 6 carbon atoms), an aralkyl group, an aryl group (preferably having 6 to 12 carbon atoms), or a heterocyclic group (preferably having 1 to 6 carbon atoms).
  • R represents an alkyl group (preferably having 1 to 6 carbon atoms), a cycloalkyl group (preferably having 3 to
  • examples of the 5-membered heterocyclic ring as represented by M include an imidazolium ring, a pyrazolium ring, an oxazolium ring, an isoxazolium ring, a thiazolium ring, an isothiazolium ring, a 1,3-dithiol ring, a 1,3,4- or 1,2,3 oxadiazolium ring, a 1,3,2-oxathiazolium ring, a 1,2,3-triazolium ring, a 1,3,4-triazolium ring, a 1,3,4-, 1,2,3- or 1,2,4-thiadiazolium ring, a 1,2,3,4-oxatriazolium ring, a 1,2,3,4-tetrazolium ring and a 1,2,3,4-thiatriazolium ring.
  • Meso-ionic compounds are known for use in the fixing step of a photographic process as disclosed in EP-A-431 568.
  • Triazolium thiolate meso-ionic compounds are well known in silver halide photography and are used e.g. for increasing temperature latitude as disclosed in JP-A-60-117240, for reducing fog as disclosed in US-A-4 615 970, in preparing silver halide emulsions as disclosed in US-A-4 631 253, in bleach etching baths as disclosed in EP-A-321 839, to prevent pressure marks as disclosed in US-A-4 624 913, in EP-A-554 585 for enhancing the printing properties and especially the printing endurance of a lithographic printing plate according to the DTR-process, etc. From these disclosures it can not be inferred that the use of such compounds in dry toner particles in combination with a CCA would enhance the charging properties of the toner particles.
  • Preferred meso-ionic compounds for use in toner particles useful in the method of this invention correspond to the formula : wherein R 1 and R 2 each independently represents an unsubstituted or substituted alkyl group, alkenyl group, cycloalkyl group, aralkyl group, aryl group or heterocyclic group, A represents an unsubstituted or substituted alkyl group, alkenyl group, cycloalkyl group, aralkyl group, aryl group, heterocyclic group or - NR 3 R 4 and R 3 and R 4 each independently represents hydrogen, an alkyl group or aryl group and wherein R 1 and R 2 or R 1 and A or R 3 and R 4 can combine with each other to form a 5- or 6-membered ring.
  • At least 0.5 % by weight of said CLA is present in the toner particles, more preferably at least 1 % by weight.
  • toner particles with a narrow charge distribution i.e. the charge of the toner particles shows a distribution wherein the coefficient of variability ( ⁇ ), i.e. the ratio of the standard deviation to the average value, is equal to or lower than 0.4 preferably lower than 0.3.
  • ⁇ coefficient of variability
  • the charge distribution of the toner particles is measured by an apparatus sold by Dr. R. Epping PES-Laboratorium D-8056 Neufahrn, Germany under the name "q-meter.
  • the invention thus not only encompasses a method for direct electrostatic printing, but also dry toner particles wherein a charge control agent (CCA) and a charge limitation agent (CLA) are incorporated.
  • CCA charge control agent
  • CLA charge limitation agent
  • said CLA is a meso-ionic compound as described above.
  • at least 0.5 % by weight of said CLA is present in the toner particles, more preferably at least 1 % by weight.
  • the invention also encompasses a device for direct electrostatic printing comprising :
  • said toner dispensing part is the sleeve of a magnetic brush carrying magnetic carrier particles and non-magnetic toner particles that have a charge control agent (CCA) and a charge limitation agent (CLA).
  • CCA charge control agent
  • CLA charge limitation agent
  • the CLA is preferably a meso-ionic compound as described above.
  • FIG. 1 A non limitative example of a device according to this invention is shown in fig 1. It comprises :
  • the location and/or form of the shield electrode (106b) and the control electrode (106a) can, in other embodiments of a device for a DEP method using toner particles according to the present invention, be different from the location shown in fig. 1.
  • a DEP device using two electrodes (106a and 106b) on printhead 106 is shown, it is possible to implement a DEP device, using toner particles according to the present invention using devices with different constructions of the printhead (106). It is, e.g. possible to implement a DEP device having a printhead comprising only one electrode structure as well as a device having a printhead comprising more than two electrode structures.
  • the apertures in these printhead structures can have a constant diameter, or can have a broader entrance or exit diameter.
  • the back electrode (105) of this DEP device can also be made to co-operate with the printhead structure, said back electrode being constructed from different styli or wires that are galvanically isolated and connected to a voltage source as disclosed in e.g US-A-4,568,955 and US-A-4,733,256.
  • the back electrode, co-operating with the printhead structure can also comprise one or more flexible PCB's (Printed Circuit Board).
  • the value of DC3/AC3 is selected, according to the modulation of the image forming signals, between the values DC3/AC3 0 and DC3/AC3 n , on a time basis or grey-level basis.
  • Voltage DC4 is applied to the back electrode behind the toner receiving member.
  • multiple voltages DC5 0 to DC5 n and/or DC4 0 to DC4 n can be used.
  • the magnetic brush 103 preferentially used in a DEP device according to the present invention is of the type with stationary core and rotating sleeve.
  • any type of known carrier particles and toner particles can successfully be used. It is however preferred to use "soft" magnetic carrier particles.
  • Soft magnetic carrier particles useful in a DEP device according to a preferred embodiment of the present invention are soft ferrite carrier particles. Such soft ferrite particles exhibit only a small amount of remanent behaviour, characterised in coercivity values ranging from about 4 kA/m up to 20 kA/m (50 up to 250 Oe).
  • Further very useful soft magnetic carrier particles for use in a DEP device according to a preferred embodiment of the present invention, are composite carrier particles, comprising a resin binder and a mixture of two magnetites having a different particle size as described in EP-B 289 663.
  • the particle size of both magnetites will vary between 0.05 and 3 ⁇ m.
  • the carrier particles have preferably an average volume diameter (d v 50) between 10 and 300 ⁇ m, preferably between 20 and 100 ⁇ m. More detailed descriptions of carrier particles, as mentioned above, can be found in EP-A-675 417.
  • toner particles with an absolute average charge over mass ratio (
  • the charge to mass ratio of the toner particles is measured by mixing the toner particles with carrier particles, and after 15 min of charging the q/m-ratio is measured as described in US-A-5 880 760. Said toner particles were pulled under vacuum from said CTC-roller to an accurately weighted filter paper (weight was WP in g), which was shielded in a Faraday cage.
  • the amount of charge that arrived, after about 5 minutes vacuum pulling and after an accurate surface area of said CTC-roller was cleaned from said toner particles, at said filter paper was measured with a Coulomb meter in ⁇ C.
  • the filter paper with the toner particles was weighted again, giving weight WPT in g.
  • the charge to mass ratio was then determined as ⁇ C/(WPT-WP).
  • the charge to mass ratio is taken as the absolute value, as a DEP device according to this invention can function either with negatively charged toner particles or with positively charged toner particles depending on the polarity of the potential difference between DC1/AC1 and DC4.
  • the toner particles used in a device according to the present invention have an average volume diameter (d v 50) between 1 and 20 ⁇ m, more preferably between 3 and 15 ⁇ m. More detailed descriptions of toner particles, as mentioned above, can be found in EP A 675 417 that is incorporated herein by reference.
  • a DEP device making use of the above mentioned marking toner particles can be addressed in a way that enables it to give black and white. It can thus be operated in a "binary way", useful for black and white text and graphics and useful for classical bi-level half-toning to render continuous tone images.
  • a DEP device is especially suited for rendering an image with a plurality of grey levels.
  • Grey level printing can be controlled by either an amplitude modulation of the voltage DC3/AC3 applied on the control electrode 106a or by a time modulation of DC3/AC3. By changing the duty cycle of the time modulation at a specific frequency, it is possible to print accurately fine differences in grey levels. It is also possible to control the grey level printing by a combination of an amplitude modulation and a time modulation of the voltage DC3/AC3, applied on the control electrode.
  • the carrier particles are of the carrier particles.
  • a macroscopic "soft" ferrite carrier consisting of a MgZn-ferrite with average particle size 50 ⁇ m, a magnetisation at saturation of 36 Tm 3 /kg (29 emu/g) was provided with a 1 ⁇ m thick acrylic coating. The material showed virtually no remanence.
  • the toner used for the experiment had the following composition : 97 parts of a co-polyester resin of fumaric acid and bispropoxylated bisphenol A, having an acid value of 18 and volume resistivity of 5.1 x 10 16 ohm.cm was melt-blended for 30 minutes at 110° C in a laboratory kneader with 3 parts of Cu-phthalocyanine pigment (Colour Index PB 15:3).
  • a resistivity decreasing substance - having the following formula : (CH 3 ) 3 N + C 16 H 33 Br - was added in a quantity of 0.5 % with respect to,the binder, as described in WO-A-94/027192.
  • the solidified mass was pulverised and milled using an ALPINE Fliessbettarnastrahlmühle type 100AFG (trade name) and further classified using an ALPINE multiplex zig-zag classifier type 100MZR (trade name).
  • the average particle size was measured by Coulter Counter model Multisizer (trade name), was found to be 6.3 ⁇ m by number and 8.2 ⁇ m by volume.
  • the toner particles were mixed with 0.5 % of hydrophobic colloidal silica particles (BET-value 130 m 2 /g) and hydrophobic colloidal titaniumoxide particles.
  • the second comparative toner was equal to comparative toner 1 (CT1) except for the addition of 3 % by weight of a charge control agent (CCA), COPY CHARGE NCA, (trade name of Clariant) to the bulk of the particles.
  • CCA charge control agent
  • COPY CHARGE NCA trade name of Clariant
  • the third comparative toner was equal to comparative toner 1 (CT1) except for the addition of 2 % by weight of a charge limitation agent (CLA), with formula to the bulk of the toner particles.
  • CLA charge limitation agent
  • the first invention toner was equal to comparative toner 1 (CT1) except for the addition of 2 % by weight of a charge control agent (CCA), COPY CHARGE NCA, (trade name of Clariant) and the addition of 0.25 % by weight of a charge limitation agent (CLA), with formula to the bulk of the toner particles.
  • CCA charge control agent
  • CLA charge limitation agent
  • the second invention toner was equal to the first one except for the addition of 0.5 % by weight of the same charge limitation agent (CLA).
  • the third invention toner was equal to the first one except for the addition of 1 % by weight of the same charge limitation agent (CLA).
  • the fourth invention toner was equal to the first one except for the addition of 2 % by weight of the same charge limitation agent (CLA).
  • the fifth invention toner was equal to the fourth one except for the toner resin, instead of 97 parts of a co-polyester resin of fumaric acid and bispropoxylated bisphenol A, AG23, an experimental hybrid resin comprising polyester and polystyrene, provided by KAO Corp. Of Japan, was used.
  • the sixth invention toner was equal to the fourth one except for the toner resin, instead of 97 parts of a co-polyester resin of fumaric acid and bispropoxylated bisphenol A, AG11, an experimental linear polyester, provided by KAO Corp. of Japan,was used.
  • An electrostatographic developer was prepared by mixing said mixture of toner particles and colloidal silica in a 5 % ratio (wt/wt) with silicon coated carrier particles.
  • the developers were used in a DEP device as described hereinbelow
  • a printhead structure (106) was made from a polyimide film of 50 ⁇ m thickness, double sided coated with a 5 ⁇ m thick copper film.
  • the printhead structure (106) had two rows of printing apertures.
  • 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 amplifier.
  • the printing apertures were rectangular shaped with dimensions of 360 by 120 ⁇ m.
  • the dimension of the central part of the rectangular shaped copper control electrodes was 500 by 260 ⁇ m.
  • a common shield electrode (106b) was arranged around the aperture zone leaving a free polyimide zone of 1620 ⁇ m.
  • Said printhead structure was fabricated in the following way. First of all the control and shield electrode pattern was etched by conventional copper etching techniques. The apertures were made by a step and repeat focused excimer laser making use of the control electrode patterns as focusing aid. After excimer burning the printhead structure was cleaned by a short isotropic plasma etching cleaning. Finally a thin coating of PLASTIK70, commercially available from Griffin Chemie, was applied over the control electrode side of said printhead structure.
  • the charged toner conveyer (CTC) The charged toner conveyer (CTC)
  • the CTC was a cylinder with a sleeve made of aluminium, coated with TEFLON (trade name of Du Pont, Wilmington, USA) with a surface roughness of 0.3 ⁇ m (Ra-value) and a diameter of 30 mm.
  • toner particles were propelled to this conveyer from a stationary core (103a)/rotating sleeve (103b) type magnetic brush (103) comprising two mixing rods and one metering roller. One rod was used to transport the developer through the unit, the other one to mix toner with developer.
  • the magnetic brush 103 was constituted of the so called magnetic roller, which in this case contained inside the roller assembly a stationary magnetic core (103a), having three magnetic poles with an open position (no magnetic poles present) to enable used developer to fall off from the magnetic roller (open position was one quarter of the perimeter and located at the position opposite to said CTC (104).
  • the magnetic brush was connected to a DC power supply (DC1) of +140 V.
  • the surface of the charged toper conveyor was positioned at 750 ⁇ m from the surface of the magnetic brush, and said surface of said charged toner conveyor was connected to an AC power supply (AC2) with a sinusoidally oscillating field of 1800 V (peak to peak) at a frequency of 3.0 kHz with +100 V DC-offset (DC2).
  • the surface of said charged toner conveyor was set via PU spacers means at 260 ⁇ m from said printhead structure.
  • the shield electrode was connected to a DC power supply (DC5) of +100 V.
  • the control electrodes were connected to a (image-wise selected) DC power source of 0 or +280 V.
  • the back electrode was placed at 1000 ⁇ m from the back side of the printhead structure and was connected to a DC power supply of +1250 V.
  • the receiving substrate was moved at a linear speed of 3 m/min, the linear speed of the charged toner conveyor was 6 m/min, and the linear speed of the magnetic brush was 30 m/min.

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EP99203349A 1999-10-12 1999-10-12 Verfahren zum direkten elektrostatischen Ducken mit Tonerteilchen modifizierter Aufladungseigenschaften Withdrawn EP1093033A1 (de)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1296203A1 (de) * 2001-08-28 2003-03-26 Seiko Epson Corporation Bilderzeugungsgerät mit einer Vorrichtung auf einer biegsamen Leiterplatte zum direkten elektrostatischen Drucken und Regelungsmitteln zum Glätten der Tonerschicht auf einer Walze für die Tonerzufuhr
EP1300728A2 (de) * 2001-09-26 2003-04-09 Seiko Epson Corporation Toner geeignet für die Verwendung in einem Bilderzeugungsapparat
CN102395424A (zh) * 2009-02-20 2012-03-28 独立行政法人科学技术振兴机构 通过恒定电场传输微米级物体以及获得机械功

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Publication number Priority date Publication date Assignee Title
US4554233A (en) * 1982-10-28 1985-11-19 Ricoh Company, Ltd. Electrophotographic toner containing triazolium compound as charge controlling agent
JPS61156141A (ja) * 1984-12-28 1986-07-15 Ricoh Co Ltd 静電潜像現像用トナ−
US4755837A (en) * 1986-11-03 1988-07-05 Xerox Corporation Direct electrostatic printing apparatus and printhead cleaning structure therefor
EP0715218A1 (de) * 1994-11-29 1996-06-05 Agfa-Gevaert N.V. Trockenentwickler für direkt-elektrostatischen Druckverfahren

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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Publication number Priority date Publication date Assignee Title
EP1296203A1 (de) * 2001-08-28 2003-03-26 Seiko Epson Corporation Bilderzeugungsgerät mit einer Vorrichtung auf einer biegsamen Leiterplatte zum direkten elektrostatischen Drucken und Regelungsmitteln zum Glätten der Tonerschicht auf einer Walze für die Tonerzufuhr
US6817701B2 (en) 2001-08-28 2004-11-16 Seiko Epson Corporation Image forming apparatus
EP1300728A2 (de) * 2001-09-26 2003-04-09 Seiko Epson Corporation Toner geeignet für die Verwendung in einem Bilderzeugungsapparat
EP1300728A3 (de) * 2001-09-26 2004-04-14 Seiko Epson Corporation Toner geeignet für die Verwendung in einem Bilderzeugungsapparat
US6863380B2 (en) 2001-09-26 2005-03-08 Seiko Epson Corporation Toner used in image forming apparatus
CN100388123C (zh) * 2001-09-26 2008-05-14 精工爱普生株式会社 图像形成装置用色料
CN102395424A (zh) * 2009-02-20 2012-03-28 独立行政法人科学技术振兴机构 通过恒定电场传输微米级物体以及获得机械功
CN102395424B (zh) * 2009-02-20 2014-04-23 独立行政法人科学技术振兴机构 通过恒定电场传输微米级物体以及获得机械功

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