US3283703A - Electrostatic printing brush powder feed system - Google Patents

Electrostatic printing brush powder feed system Download PDF

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Publication number
US3283703A
US3283703A US387017A US38701764A US3283703A US 3283703 A US3283703 A US 3283703A US 387017 A US387017 A US 387017A US 38701764 A US38701764 A US 38701764A US 3283703 A US3283703 A US 3283703A
Authority
US
United States
Prior art keywords
brush
powder
roller
periphery
image
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
Application number
US387017A
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English (en)
Inventor
Clyde O Childress
Harold W Bonner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CROCKER CITIZENS NAT BANK
CROCKER-CITIZENS NATIONAL BANK
Original Assignee
CROCKER CITIZENS NAT BANK
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 CROCKER CITIZENS NAT BANK filed Critical CROCKER CITIZENS NAT BANK
Priority to US387017A priority Critical patent/US3283703A/en
Priority to GB10986/65A priority patent/GB1036983A/en
Priority to DEE29087A priority patent/DE1237143B/de
Priority to CH560765A priority patent/CH435982A/de
Application granted granted Critical
Publication of US3283703A publication Critical patent/US3283703A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0822—Arrangements for preparing, mixing, supplying or dispensing developer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M1/00—Inking and printing with a printer's forme
    • B41M1/12—Stencil printing; Silk-screen printing
    • B41M1/125—Stencil printing; Silk-screen printing using a field of force, e.g. an electrostatic field, or an electric current
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0806—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer on a donor element, e.g. belt, roller
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G17/00—Electrographic processes using patterns other than charge patterns, e.g. an electric conductivity pattern; Processes involving a migration, e.g. photoelectrophoresis, photoelectrosolography; Processes involving a selective transfer, e.g. electrophoto-adhesive processes; Apparatus essentially involving a single such process
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S101/00—Printing
    • Y10S101/37—Printing employing electrostatic force

Definitions

  • This invention relates to a powder feed system for a brush used in electrostatic printing systems of the type wherein said brush transfers said powder into an electric field through an image screen electrode, and more particularly to improvements therein.
  • an electrostatic printing system which comprises a system wherein electroscopic powder particles are applied to the surface of an image receiving member which is positioned in an electric field defined on one side by an image forming member and on the other side by a back plate.
  • the image forming member may comprise a screen having only the openings therein unblocked which are in a pattern in accordance with the image desired.
  • the powder particles may be entered into the electric field by means of a brush which first has the powder applied to the surface thereof and then is rolled over the image defining member to urge the powder particles through the openings therein into the electric field.
  • One of these methods is to redistribute the powder remaining on the brush by means of oscillating rollers or by using a shroud over the brush with a comb-like series of vanes which channel the powder across the brush to provide redistribution thereof on the brush surface.
  • a constant amount of powder is then added along the full length of the brush by means such as a vibrating hopper containing the powder.
  • the redistribution apparatus causes greatly increased wear on the brush and only approximately compensates for uneven depletion of the powder on the brush. It has also been found difficult to meter new powder onto the brush surface at a rate precisely corresponding to the diiferent amounts used by reason of the diiferent image densities along the image screen, so as to prevent a gradually increasing surplus or deficit.
  • An object of this invention is to provide an arrangement for substantially replenishing the supply of electro- 3,283,703 Patented Nov. 8, 1966 scopic powder to a brush in amounts required to propenly perform such replenishment without causing excessive replenishment or depletion.
  • Another object of the present invention is to provide an improved arrangement for supplying electroscopic powder to a brush in an electrostatic printing system wherein the ghosting problem is eliminated.
  • Yet another object of the .present invention is to provide a novel and improved system for supplying electroscopic powder to a brush used for electrostatic printing.
  • FIGURE 1 is an isometric view of the brush powder feed arrangement in accordance with this invention.
  • FIGURE 2 is a front view of the embodiment of the invention shown in FIGURE 1.
  • FIGURE 3 is a side view of another brush powder feed arrangement in accordance with this invention.
  • FIGURE 4 shows yet another arrangement of a brush powder feed system in accordance with this invention.
  • FIGURE 5 shows a brush powder feed arrangement in accordance with this invention for sup-plying powder to a brush which is positioned above the image screen electrode.
  • FIGURE 1 is an isometric view illustrating how the embodiment of this invention is employed tor replenishing a brush in an electrostatic writing system with electroscopic powder particles, in a manner so that the brush is evenly loaded despite the powder demands there o-n.
  • An electrostatic printing system comprises on image forming electrode or screen :10 and spaced therefrom and parallel thereto is a back plate 12. Both are made conductive for the purpose of establishing an electric field therebetween Wlhen a source of field potential 14 is connected to them.
  • An image receiving member 16 which may be paper,
  • the screen 10 has apertures therethrough which have the shape of the desired image, be it a letter, number, or pattern. 'By way of example, on the image screen 10 there are shown large letters .18, smaller 'letters 20, and a pattern 22.
  • a brush 24 is relied over the screen surface. Electroscopic powder is deposited on the brush fibers and as the brush rolls over the screen, the powder particles which transports -them to the receiving substrate 16.
  • a are smaller than the openings in the screen 10, are urged through the .screen openings into the electric field which They are deposited on the substrate with an image pattern substantially identical with the image pattern formed in the screen.
  • the substrate 16 is removed after the brush has traversed the screen area and .the powder image which is deposited thereon is fixed by known arrangements such as heating or fusing the powder :to the paper, or by spray, or other arrangements depending upon the kind of pigment powder which is employed.
  • a powder transfer roller 30 having a solid and imperforate surface which is rotatably supported within a powder container 32, in a manner so that the periphery of the powder transfer roller is in friction-al contact with the surface of the brush 24.
  • the powder container 32 holds powder 34 in the bottom thereof and the roller 30 picks up the powder from the bottom of the container.
  • a sparsely fibered brush 34 is provided in order to maintain the powder in the container 32 in a fluidized state so as to adequately coat the powder transfer rollers 30.
  • known mechanisms such as a sparsely fibered brush 34 are provided.
  • the brush 36 is rotatably supported in the container 32 and has its periphery in engagement with the powder transfer roller 30 and rotates when the powder transfer roller 30 rotates.
  • Alternative means may be the use of very llow pressure air fed into the container 32 through a porous base plate or, by vibrating the container.
  • the brush 24 may be independently rotatably driven by a motor 40, to the shaft of which the brush 24 is coupled.
  • the motor 40 is supported on a frame 42.
  • the container 32 is also attached to the frame 42.
  • the frame 42 is reciprocally moved baove the screen '18 for the purpose of bringing the brush 24 in contact with the entire surface of the said screen.
  • the direction of rotation of the brush 24 is reversed for the purpose of maintaining the velocity of the brush periphery relative to the screen constant, which secures a constant density print.
  • the frame 42 carries the brush powder replenishing mechanism, constituting the embodiment of this invention, the brush powder load and thereby the powder feed is maintained constant over the entire surface of the screen.
  • the frame 42 is reciprocally actuated by an reciprocal drive device 44 to which it may be attached. This may be, by way of example, a motor which drives reciprocally a gear, not shown, which traverses a rack 46 having the proper 'length.
  • the powder transfer roller has its surface solid and substantially imperforate and made of a material having t-riboelectric properties such that elect-roscopic powder particles in the container 32 will adhere to its surface and thereby, when removed by the brush, will have acquired a charge of the desired sign.
  • the roller by virtue of its triboelectric property, picks up a uniform layer of powder.
  • this powder Upon revolving the brush and roller, this powder will transfer and adhere to the brush, up :to a limited saturation point. Further contact does not substantially increase the amount of powder on the brush.
  • the powder will remain uniform on both transfer roller and brush until the powder is removed from the brush by the image electrode powder. Powder will then transfer from the roller to the brush and from the reservoir to the roller in suflicient amounts to restore the equilibrium of the system.
  • the brush is constantly replenished in direct area and volume correspondence to the demand of the density distribution required by the screen image.
  • a transfer roller was made of a polymethylmethacrylate such as Plexiglas and operated in a power reservoir trough of the same material.
  • the brush periphery was made of mohair pile fabric.
  • the electroscopic powder which was employed, is known as Xerox Toner Green, manufactured by the Xerox Company. This powder acquired a negative charge by contact with the Plexiglas roller.
  • the image electrode was made negative relative to the back plate.
  • the roller was made of a polytetrafluoroethylene known as Teflon.
  • the electroscopic powder used was Rocket Red A13, manufactured by the Switzer Corporation.
  • the container was constructed of aluminum.
  • the powder which is charged positive requires for transfer by the electric field, that the image electrode be positive relative to the back plate.
  • the choice of materials and charge direction may be arbitrary with some electroscopic powders, but may show improved performance in a given charge direction with those powders which accept and hold charges of one sign more readily than charges of the other sign.
  • the presence of such charge variations in the brush may be easily ascertained by axially isolating cylindrical sections of such a brush so that they may be independently monitored by a suitable electrometer.
  • a mohair plush fabric suitable for such a brush has a fiber length of 4 mm., which when compressed between 1 cm. plates to a depth of 3 mm. has a resistivity of 10 ohms at 40% relative humidity.
  • Transfer rollers of solid plastic construction as well as rollers with a thin layer of plastic laminated to a conductive core, which may be grounded, have operated successfully in the described configurations.
  • a triboelectric charge exchange where more than two materials is involved may be quite complex. It is interesting to note that polished polymethyl methacrylate plastic, such as Rohm & Hass Plexiglas, will acquire a positive charge relative to a mohair fabric surface; however, if the Plexiglas has been machined, it will acquire a negative charge relative to the same material. A typical electroscopic powder, such as Xerox Toner Green, will acquire a n gative charge from either a machined or polished Plexiglas surface or from a combination of either with a mohair pile surface.
  • polished polymethyl methacrylate plastic such as Rohm & Hass Plexiglas
  • a further control of the amount of powder picked up on the transfer roller and thus available to the brush may be exercised by increasing the surface area of the powder transfer roller material by the use of suitable grooves or indentations 30A in the surface of the roller 30.
  • FIGURE 3 shows another arrangement, in accordance with this invention, for improving the brush powder feed mechanism.
  • Those structures which have functions similar to the structure shown in FIGURE 1 bear similar reference numerals.
  • two rollers 50, 52 which may be the same as the roller 3%, are rotatably supported, on either side of the brush 24, also to be in frictional engagement therewith and to be rotated by the rotation of the brush 24.
  • These idler rollers 50, 52 serve the function of picking up and redistributing any localized overload of powder that may result from agglomerates which are caused by insufficient fluidization in the powder reservoir 36.
  • the powder reservoir 36 in this figure of the drawing, is vibrated by a vibratory device 54 which may be an electromagnetic transducer such as a piezoelectric crystal or magnetostrictive device.
  • vibration of the container can serve to fluidize the powder therein so that a more uniform layer thereof may be deposited on the surface of the roller 30.
  • FIGURE 4 shows another variation of the embodiment of the invention.
  • a brush roller 56 which is rotatably supported within the container 36, is rotatably driven as a result of frictional engagement with the powder transfer roller 30 which in turn is frictionally engaged with the periphery of the brush 24 which is rotatably driven, as previously described.
  • the brush 56 picks up powder from the powder reservoir and this powder is transferred to the powder transfer roller 30 which in turn loads the brush 24 so that a uniform powder supply is contained thereby.
  • FIGURE 5 is shown to illustrate the use of an endless belt 60, which is made of triboelectric material, and which may be used in place of the roller 30 to load the brush 24.
  • the endless belt 60 is supported on four suitably spaced idler rollers respectively 62, 64, 66, 68.
  • the belt is held to be in frictional engagement with the periphery of the brush 24 so that as it rotates it causes the belt to travel, dipping into the powder container 32 for a charge of particles which are then transferred to the surface of the roller 24 as required.
  • an electrostatic printing system of the type wherein electroscopic powder is applied from a reservoir to a brush which is rotatably moved over the surface of an image forming screen electrode to transfer powder particles therethrough into an electric field
  • the improvement comprising a first roller having its surface made of a plastic material and having triboelectric properties, means for supporting said first roller rotatably with one portion of its periphery in frictional engagement with the periphery of said brush to be rotatable therewith, means for applying powder from said reservoir to another portion of said first roller periphery, and means for redistributing excess powder over the surface of said brush comprising a second roller having its surface made of plastic material and having triboelectric properties, and means for supporting said second roller rotatably with its periphery in frictional engagement with another portion of the periphery of said brush.
  • roller surface is made of polytetrafiuoroethylene.
  • roller surface is made of polymethylmethacrylate.
  • each said roller surface has a plurality of grooves thereon for increasing the surface area thereof.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Molecular Biology (AREA)
  • Brushes (AREA)
  • Feeding Of Articles By Means Other Than Belts Or Rollers (AREA)
  • Inking, Control Or Cleaning Of Printing Machines (AREA)
  • Printing Methods (AREA)
US387017A 1964-08-03 1964-08-03 Electrostatic printing brush powder feed system Expired - Lifetime US3283703A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US387017A US3283703A (en) 1964-08-03 1964-08-03 Electrostatic printing brush powder feed system
GB10986/65A GB1036983A (en) 1964-08-03 1965-03-16 Electrostatic printing brush powder feed system
DEE29087A DE1237143B (de) 1964-08-03 1965-04-09 Puderaufgabevorrichtung fuer eine Buerste in elektrostatischen Drucksystemen
CH560765A CH435982A (de) 1964-08-03 1965-04-22 Elektrostatische Druckeinrichtung

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US387017A US3283703A (en) 1964-08-03 1964-08-03 Electrostatic printing brush powder feed system

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Publication Number Publication Date
US3283703A true US3283703A (en) 1966-11-08

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US387017A Expired - Lifetime US3283703A (en) 1964-08-03 1964-08-03 Electrostatic printing brush powder feed system

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US (1) US3283703A (de)
CH (1) CH435982A (de)
DE (1) DE1237143B (de)
GB (1) GB1036983A (de)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3358594A (en) * 1966-01-17 1967-12-19 American Can Co Electrostatic printing with a magnetic brush feed
US3380436A (en) * 1965-03-26 1968-04-30 Molins Machine Co Ltd Printing apparatus
US3473467A (en) * 1965-06-03 1969-10-21 Owens Illinois Inc Methods and apparatus for electrical printing
US3574301A (en) * 1969-04-02 1971-04-13 Xerox Corp Developing apparatus
US3638613A (en) * 1969-03-10 1972-02-01 Xerox Corp Toner developer system
US3687106A (en) * 1969-07-11 1972-08-29 Xerox Corp Donor apparatus and method
US3848566A (en) * 1969-07-11 1974-11-19 Xerox Corp Donor apparatus
US3900002A (en) * 1972-05-10 1975-08-19 Xerox Corp Donor apparatus
US4018187A (en) * 1976-06-30 1977-04-19 International Business Machines Corporation Grooved magnetic brush roll
WO1985002920A1 (en) * 1983-12-19 1985-07-04 Minnesota Mining And Manufacturing Company Magnetically attractable developer material transport apparatus
US5355794A (en) * 1990-08-17 1994-10-18 Herbert Freudenheim Process and apparatus for dry printing
EP0823673A3 (de) * 1996-07-08 1998-06-10 Aetas Peripheral Corporation Entwicklungseinheit und Entwicklungsverfahren

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102022113575B4 (de) * 2022-05-30 2025-05-08 Holger Volz Beschichtungsvorrichtung und Verfahren zum Beschichten eines flächigen Werkstückes mit der Beschichtungsvorrichtung

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2224391A (en) * 1939-06-06 1940-12-10 William C Huebner Process of and apparatus for printing
US2959153A (en) * 1955-12-21 1960-11-08 Ibm Xerographic image developing apparatus
US3081698A (en) * 1960-03-04 1963-03-19 Electrostatic Printing Corp Electrostatic printing system
US3140199A (en) * 1961-04-28 1964-07-07 Eastman Kodak Co Vibrating belt powder cloud generator for xerography
US3145122A (en) * 1962-08-13 1964-08-18 Addressograph Multigraph Apparatus for applying developer powder to photo-conductive insulating material
US3152012A (en) * 1960-12-19 1964-10-06 Ibm Apparatus for the development of electrostatic images
US3160091A (en) * 1959-05-14 1964-12-08 Xerox Corp High speed xeroprinter and method therefor
US3202092A (en) * 1963-02-01 1965-08-24 Electrostatic Printing Corp Electrostatic printing system

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2224391A (en) * 1939-06-06 1940-12-10 William C Huebner Process of and apparatus for printing
US2959153A (en) * 1955-12-21 1960-11-08 Ibm Xerographic image developing apparatus
US3160091A (en) * 1959-05-14 1964-12-08 Xerox Corp High speed xeroprinter and method therefor
US3081698A (en) * 1960-03-04 1963-03-19 Electrostatic Printing Corp Electrostatic printing system
US3152012A (en) * 1960-12-19 1964-10-06 Ibm Apparatus for the development of electrostatic images
US3140199A (en) * 1961-04-28 1964-07-07 Eastman Kodak Co Vibrating belt powder cloud generator for xerography
US3145122A (en) * 1962-08-13 1964-08-18 Addressograph Multigraph Apparatus for applying developer powder to photo-conductive insulating material
US3202092A (en) * 1963-02-01 1965-08-24 Electrostatic Printing Corp Electrostatic printing system

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3380436A (en) * 1965-03-26 1968-04-30 Molins Machine Co Ltd Printing apparatus
US3473467A (en) * 1965-06-03 1969-10-21 Owens Illinois Inc Methods and apparatus for electrical printing
US3358594A (en) * 1966-01-17 1967-12-19 American Can Co Electrostatic printing with a magnetic brush feed
US3638613A (en) * 1969-03-10 1972-02-01 Xerox Corp Toner developer system
US3574301A (en) * 1969-04-02 1971-04-13 Xerox Corp Developing apparatus
US3687106A (en) * 1969-07-11 1972-08-29 Xerox Corp Donor apparatus and method
US3848566A (en) * 1969-07-11 1974-11-19 Xerox Corp Donor apparatus
US3900002A (en) * 1972-05-10 1975-08-19 Xerox Corp Donor apparatus
US4018187A (en) * 1976-06-30 1977-04-19 International Business Machines Corporation Grooved magnetic brush roll
WO1985002920A1 (en) * 1983-12-19 1985-07-04 Minnesota Mining And Manufacturing Company Magnetically attractable developer material transport apparatus
US5355794A (en) * 1990-08-17 1994-10-18 Herbert Freudenheim Process and apparatus for dry printing
EP0823673A3 (de) * 1996-07-08 1998-06-10 Aetas Peripheral Corporation Entwicklungseinheit und Entwicklungsverfahren

Also Published As

Publication number Publication date
DE1237143B (de) 1967-03-23
CH435982A (de) 1967-05-15
GB1036983A (en) 1966-07-20

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