US3640246A - Development apparatus for latent electrostatic images - Google Patents

Development apparatus for latent electrostatic images Download PDF

Info

Publication number
US3640246A
US3640246A US874746A US3640246DA US3640246A US 3640246 A US3640246 A US 3640246A US 874746 A US874746 A US 874746A US 3640246D A US3640246D A US 3640246DA US 3640246 A US3640246 A US 3640246A
Authority
US
United States
Prior art keywords
chamber
ion generator
cloud
baffle
latent electrostatic
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
US874746A
Other languages
English (en)
Inventor
Lothar S Jeromin
Hazen L Hoyt
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.)
Xerox Corp
Original Assignee
Xerox Corp
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 Xerox Corp filed Critical Xerox Corp
Application granted granted Critical
Publication of US3640246A publication Critical patent/US3640246A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • G03G15/0803—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer in a powder cloud
    • 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
    • Y10S118/00—Coating apparatus
    • Y10S118/05—Fluidized bed

Definitions

  • a cloud of toner particles is OI I I introduced into the devglopment chamber through a port in 250/49-5 the wall directly opposite the ion generator wall.
  • OI I I introduced into the devglopment chamber through a port in 250/49-5 the wall directly opposite the ion generator wall.
  • Above the powder cloud port and the apertures in the ion generator wall [56] References cued and extending completely between the opposed walls, is a baffle under which the powder and toner clouds meet and are UN D STA PA HE TES TENTS thoroughly mixed.
  • a grid electrode positioned above the bafet ..I X fle and spaced much further from [he photoconducfive sup- 2,824,813 1958 Falls" etal Hg/637 X face than a conventional powder cloud development elec- 2341456 7/ 1 958 Carlson 1 13/637 x trode, is utilized to control image quality and contrast. 2,859,127 11/1958 Matthews...
  • a uniform electrostatic charge is deposited on the surface of a xerographic plate and a j latent electrostatic image is created by projecting the penetrating radiation, such as X-rays or gamma rays, through the object and onto the plate surface.
  • the latent electrostatic image may be made visible by contacting the latent electrostatic image on the plate surface with fine powdered particles electrically charged opposite to the latent electrostatic image pattern on the plate.
  • the visible image may be viewed, photographed or transferred to another surface where it may be permanently affixed or otherwise utilized. The entire processing is dry and no dark room is necessary.
  • xeroradiography in recent years has been utilized to detect breast cancer in women.
  • xeroradiography In examination of. breasts wherein soft tissue comprises most of the breast area, xeroradiography, or xeromammography as it is generally called, provides greater resolving power than the conventional roentgenographic film and greater image detail is achieved.
  • a wide range of contrast is seen on the xeroradiographic plate as compared to the conventional roentgenographic films so that all the structures of the breast from the skin to the chest wall and ribs may be readily visualized.
  • xeromammography detects small structures like turner calcification and magnifies them more than conventional film, is quicker, less expensive, gives greater detail and requires less radiation nonphotoconductive prior X-ray techniques.
  • Various prior art techniques for charging the powder cloud include turbulently flowing the powder particles in air through a nozzle, tube or the like to triboelectrically charge the particles or by passing the particles through a corona discharge area comprising a fine needle or fine wire and a grounded electrode as disclosed in U.S. Pat. No. 2,725,304.
  • the corona method of charging the particles has been found to provide more uniform charging of the powder cloud, thereby producing high resolution images when the xerographic plate is developed.
  • Prior are devices which utilized a corona discharge to charge the powder particles such as that set forth in U.S. Pat. No. 2,725,304, have disadvantages associated therewith.
  • the powder particles when introduced into the chamber and charged, may accumulate around the corona discharge electrode such that the electrode ceases to charge powder particles entering the chamber area.
  • the electrode may be cleaned periodically to remove the powder particles therefrom the necessity of cleaning the corona electrode is time consuming, may increase the cost of development, the complexity of the development operation is increased and the particles may deposit on the person manually cleaning the electrode.
  • an ion generator and a powder cloud generator the generators serving to respectively introduce a cloud of ions and a cloud of toner particles into the development chamber.
  • the ion generator is enclosed in a housing which has a plurality of openings along a wall thereof adjacent the development chamber. Air introduced into the housing adjacent the energized high-voltage wire or wires carries ions into the development chamber through the openings. The airflow is chosen such that a positive pressure differential is maintained between the ion generator housing and the development chamber. This pressure differential prevents the flow of toner particles into the ion generator housing such that the possibility of contamination of the high-voltage wire in the housing is substantially minimized.
  • the ion generator is adjacent one sidewall of the development chamber.
  • a cloud of toner particles is introduced into the development chamber through a port in the sidewall opposite from the ion generator, the cloud of ions and the cloud of toner particles meeting under a baffle, extending between the opposed walls, where they thoroughly mix to form a cloud of charged toner particles.
  • the ion generator egress ports and the powder cloud port arepositioned only under the baffle whereby thorough mixing of the clouds is assured.
  • the charged powder cloud is caused to swirl out from underthe baffle toward the upper portion of the development chamber where the charged toner particles pass through and around a grid electrode, and are attracted to the latent electrostatic image, whereby the latent image is made visible.
  • the baffle extend the entire distance between the opposed sidewalls, whereby discharge of portions of the latent image by free ions and over-development of portions of the latent electrostatic image by toner particles carried to the top of the development chamber in the absence of the proper baffle, as described herein, is avoided.
  • a grid electrode is spaced above the baffle at a distance of about 1 to about 2 inches, generally on the order of about 1% inches, from the photoconductive surface.
  • the grid electrode separates particles charged to an undesired polarity.
  • the electrode is further spaced from the photoconductive surface than is normal for a powder cloud development electrode and the charged powder cloud is caused to enter into the zone above the electrode, the toner particles, charged to a polarity for developing the latent electrostatic image, will be accelerated toward the latent image and away from the grid electrode which is biased to the same polarity.
  • FIG. 1 is a cross-sectional view of a powder cloud development apparatus incorporating the teachings of the present invention.
  • FIG. 2 is a top plan view, partially in section, of the development apparatus of FIG. 1.
  • development means I includes a rigidly mounted backing plate I02 positioned above development chamber 104 and slightly above the path of xerographic plate travel therebetween.
  • the xerographic plate is shown schematically as having a conductive backing member 106 and a downwardly facing photoconductive layer 108 thereon.
  • the development means of FIGS. I and 2 herein is part of an automated flat-plate xerographic processing system.
  • Development chamber 104 rests on inflatable elements I supported, in turn, by brackets 112.
  • the walls Ill l of chamber 104 terminate, about the upper periphery thereof, in outwardly extending lip 116.
  • Attached to lip 116 is a gasket supporting member 118 having gasket I20 on the upper portion thereof.
  • Grid electrode I24 mounted on support bracket 126.
  • Grid electrode I24 can be, for example, 0.010-inch diameter wire strung on a frame at approximately %-inch spacing and is typically biased on the order of about $1,000 volts.
  • a canopy shaped baffle I30 made of insulator material.
  • an ion generator 132 comprising housing 134, a single corotron wire 136 therein and air inlet ports 138, coupled to a pressurized air source 139 by conduit 140.
  • a plurality of ionized air egress ports I42 are adjacent the ends of corotron wire 136 whereas ionized air egress ports 143 are adjacent the middle of the wire.
  • the air entering through ports I38 scavenges the ions created by the corotron wire as the air flows from ports 138 through the ion generator to ports 142, where the ionized air exits to that portion of the development chamber beneath baffle 130.
  • Extending through the sidewall of the development chamber directly opposite ion generator 132 is a toner entrance port 144, also positioned beneath baffle I30. Port 144 is connected to toner aerosol generator 146, including source 149 of pressurized gas, by way of flexible coupling I48.
  • Pads I50 Adjacent at least a portion of the side of development chamber 104 are porous pads I50, securely mounted to the external sides of the development chamber. Pads I50 are adapted to permit the passage of air therethrough whereby suitable minimum pressure differential can be maintained between development chamber 104 and the external environment outside the chamber. This prevents pressure buildup in the chamber which would cause seal leakage with attendant leakage of toner to the internal portions of the surrounding enclosure. Pads 150 are of limited porosity such that while airflow can be maintained therethrough, toner particles cannot pass therethrough into the internal portions of surrounding enclosure. It should be noted that the ion generator 132 may be located external to development chamber 104 if so desired with appropriate entrance points made through the walls of the development chamber to enable the ions to enter and mix with the powder cloud under baffle 130.
  • Port 152 At the bottom of the development chamber, in the bottom wall thereof, there is a port 152 through which unused toner is withdrawn during the purge cycle. Port 152 is connected to conduit 154 by means of flexible coupling 156. Inside conduit I54, there is a flapper valve 158 hinged for rotational movement, in the direction as shown by the arrow, about hinge 160. Conduit I54 is connected to toner filter means 162 which, in turn, is connected to blower means 164. At the beginning of the purge cycle, valve 158 is moved downward and to the left under the action of rotary solenoid (not shown).
  • flapper valve 158 places the blower in communication with the development chamber through toner filter means I62, conduit 154 and port 152, whereby unused toner is withdrawn from the development chamber. After the purge cycle, the valve is released from its open position and rotated back into the closed position under urging of a spring (not shown).
  • Backing plate 102 also has a plurality of apertures 171, 173, I75 and I77 therethrough adapted to receive pins 179 extending upwardly from the movable development chamber 104, the pins serving to guide the chamber into the proper sealing position about the photoconductive surface.
  • switch 51 mounted on top of plate I02 is switch 51 having an arm depending downwardly through a slot in the backing plate.
  • switch S2 Positioned adjacent aperture I75 is a switch S2 which is actuated when a pin passes through the aperture.
  • Adjacent aperture 171 is a switch S3 which is actuated when the development chamber is lowered and the pin which had passed through aperture 171 is no longer in contact therewith.
  • Development means 100 is of the powder cloud type wherein a fine cloud of charged toner particles is created by powder cloud generator 146, for example, as shown in US. Letters Pat. Nos. 2,812,883 or 2,862,646, and blown into development chamber 104 through port 144.
  • the powder cloud so generated by the powder cloud generator is then mixed with an ion cloud produced by passing pressurized air over corotron wire 136 and then through egress ports 142 in housing 134.
  • the powder cloud and the ion cloud meet under baffle 130 and are thoroughly mixed.
  • the charged powder cloud within the development chamber is caused to swirl out from under baffle 130 toward the upper portion of the development chamber where the charged toner particles are attracted to the latent electrostatic image, whereby the latent image is made visible.
  • the positive pressure differential maintained between ion generator 132 and development chamber 104 prevents the toner particles from entering the ion generator housing and contaminating or clogging the corotron wire or the ion generator egress ports 142.
  • This pressure differential is created and maintained by limiting the number and size of ports 142 in relation to the pressure applied to housing 134 through pressure controlled communication with the pressurized air source.
  • a pressure differential in the range from about 4 inches of water to about 18 inches of water has been successfully utilized to prevent such contamination.
  • Grid electrode 124 which is biased oppositely from the polarity of the latent-electrostatic image, when it is desired to form a positively sensed reproduction, is utilized to remove particles or ions which have the same polarity as the latent electrostatic image and to establish field lines normal to the photoconductive surface whereby the phenomenon of edge deletion can be controlled, as desired.
  • substantial, or at least partial, retention of edge deletion i.e., edge enhancement
  • the grid electrode also serves to accelerate the movement toward the photoconductor surface of those particles, of like polarity to the bias potential, which are between the grid and the photoconductor surface.
  • switches S2 and S4 initiate the development cycle, they do so by actuating master timer means (not shown) which controls the development operations broadly described above in accordance with the following sequence.
  • pressurized air is continuously applied to the corotron housing and the grid electrode is appropriately biased.
  • the positive pressure differential on the order of about 4-18 inches of water, thereby established between the ion generator housing and the development chamber proper serves to prevent toner particles, subsequently blown into the development chamber, from entering the ion generator housing and adversely affecting the operational characteristics of the ion generator.
  • the toner powder cloud generator is pulsed one or more times to fill the development chamber with a charge of toner particles, theair applied to the corotron housing being at sufficient pressure to prevent toner particles from entering the housing.
  • pulsation of the toner feed mechanism is on the order of about 0.25-0.6 second.
  • the powder cloud generator is initially pulsed by itself to avoid discharge of the latent electrostatici image by charged ions blown into the development chamber in the absence of toner particles. Thereafter, the powder cloud generator and the ion generators are simultaneously pulsed a plurality of times, for example, 6 times.
  • the pulsation of the ion generator, by energizing corotron wire 136, is on the order of about l-3 seconds.
  • a typical pulse-off time period is on the order of about 5 seconds, after which the powder cloud and ion generators are pulsed together (for their respective pulsing periods) and then off a plurality of times, as indicated above, in successive 5 second intervals.
  • the toner cloud and the ion cloud injected into the development chamber from opposite sides, meet under baffle 130, where they are thoroughly mixed. Due to the flow rates chosen for the ion and powder clouds, the now charged toner cloud swirls out from under the baffle, rises through and around the biased grid electrode to the top of the development chamber where toner particles, normally charged to a polarity opposite that of the polarity of the latent electrostatic image, are drawn thereto whereby the latent electrostatic image is made visible.
  • the aforementioned operating characteristics can be varied by the operator or radiologist to give the desired developmental results, e.g., best images for viewing, most efiicient use of toner, etc.
  • the presence of free ions i.e., ions unattached to toner particles
  • their discharge of portions of the latent electrostatic image can be, to a great extent, controlled, such that the final reproduction is not adversely degraded.
  • the master timer means actuates the rotary solenoid associated with flapper valve 158 such that the valve is caused to rotate to the position where the development chamber is in communication with blower 164 via filter means 162. Air is drawn into the chamber via filter pads 150 and helps to entrain unused toner. In this manner, unused toner is purged from the development chamber.
  • the purge duration timer normally set for a purge duration on the order of about 6 seconds, the rotary solenoid is deactuated,
  • flapper valve 158 is spring urged back to the position as shown in FIG. 1. Additionally, at the end of the purge cycle the three-way valve to inflatable elements is opened to the atmosphere, thereby causing the pressurized gas to be releasedfrom the inflatable elements whereby the development chamber is lowered from the leaktight position under the combined influence of gravity and spring means (not shown).
  • the xerographic processing cycle To complete the xerographic processing cycle, it is lnecessary to withdraw a single support sheet from a supply tray, transport it to a point where it is in registration with the xerographicplate having the powder image thereon, transfer the powder image to the support sheet as the plate and the support sheet are moved in synchronization, strip the image-bearing support sheet from its position adjacent the xerographic plate and transport it to a fuser where the powder image is permanently bonded to the adjacent support sheet surface. Simultaneously, the xerographic plate is cleaned and processed for subsequent reuse.
  • the baffle which defines the zone in which the toner cloud and the ion cloud initially mix is dimensioned and shaped to provide a uniform distribution of toner in the upper section of the development chamber as each cloud is moved out from under it during succeeding pulses of the toner and ion generator apparatus.
  • this movement of the charged powder cloud is affected by the kinetic energy imposed on the toner particles from the powder cloud generator system and by the convection currents set up by the continuous flow of air from the ion generator system.
  • the shape of the baffle should be such as to provide for proper charged powder cloud move ment to the development zone adjacent the charged xerographic plate.
  • the bias applied to the grid electrode attracts to the grid toner particles and free ions charged to the opposite polarity as the bias potential. In this manner, it suppressed the movement of free ions which might adversely affect image quality through image discharge.
  • the electrode also accelerates the movement toward the photoconductive surface of those toner particles between the grid and the photoconductive surface which are charged to the same polarity as the polarity of the grid bias potential. It is this accelerated cloud of particles that is to be used in the development of the latent image.
  • the grid electrode assists in controlling the contrast of the developed image by providing an electrostatic field to counteract the fringing fields associated with the edges between adjacentareas of varying charge density.
  • the grid electrode In controlling the contrast of the image, the grid electrode also serves to increase the exposure latitude of a xerographic system. This is, the grid electrode provides the radiologist with a more versatile system which will give him essentially the same information content, in the final image, in a wider variety of exposure conditions with a minimum change in his exposure technique.
  • the grid electrode makes it possible to develop both positive and negative images.
  • the selenium photoconductor is positively charged.
  • the latent image remaining after exposure is therefore of positive potential.
  • the grid electrode is provided with a negative potential bias.
  • the negatively biased grid attracts positively charged particles (not ions) and at the same time causes the negatively charged particles, in the zone between the grid and the plate, to be accelerated toward the plate surface.
  • the field lines in this system generally exist between those portions of the grid opposite those areas on the plate which contain fairly high positive potential in the latent image. In order to increase development in plate areas of lesser plate charge, it is necessary to increase the bias potential on the grid, thus creating a more effective field to bring additional toner in these areas.
  • the grid bias is of positive potential.
  • the positive potential on the grid tends to attract the negatively charged toner particles and ions and at the same time causes the positively charged toner particles, between the grid and the plate surface, to be accelerated toward the uncharged or relatively uncharged areas of the plate surfuce.
  • a grounded grid electrode spaced from the bottom wall of the development chamber. Though relatively closely spaced to the bottom wall, the grid should not extend under baffle so as to adversely affect the powder cloud-ion cloud mixing process, nor should it be so close to the bottom wall as to be easily and rapidly covered by accumulated toner.
  • the electrode serves to collect free ions not attached to toner particles in the charged cloud. Additionally, since the electrode is in grid form and toner particles call fall therethrough, the electrode, to some extend, minimizes the field effect of toner accumulated at the bottom of the develop ment chamber beneath the grid. In this regard, the electrode serves to isolate any charge which might be residing on the in sulative toner particles which have fallen through the grid.
  • Prolonged deposition of toner particles on either or both of the grid electrodes can significantly affect, if not removed, the operational characteristics of the development chamber. Accordingly, mechanical cleaning of the electrodes is periodically required. This can be achieved, for example, by causing a brush to traverse the grid electrode between development cycles, preferably in an automated mode after each complete development cycle.
  • a brush to traverse the grid electrode between development cycles, preferably in an automated mode after each complete development cycle.
  • the adverse affects including possible breakdown with free ion generation between the grid and the plate surface which might cause localized discharge of the plate, can be virtually eliminated.
  • a grid of parallel conductors as opposed to an intersecting grid of parallel and perpendicular conductors, is preferred since essentially total toner removal is more easily achieved.
  • baffle and grid electrode described above can be utilized in a system where the developer particles are charged by triboelectrification (i.e., in the absence of charging by means of the ion generator described above).
  • the grid electrode functions to separate the toner particles of undesired charge and to accelerate the toner particles of desired charge, between the grid and the latent electrostatic image-bearing surface, towards the latent image. This is in addition to the previously stated function of modifying the electrostatic field lines associated with the latent electrostatic image.
  • An apparatus for developing a latent electrostatic image on a surface comprising a chamber having a pair of opposed sidewalls, support means for supporting said surface with its latent electrostatic image-bearing side facing said chamber, means for supplying a cloud of developer particles to said chamber through a port in one of said opposed sidewalls, ion generator means for supplying a cloud of ions to said chamber through at least one port in the other of said opposed sidewalls, means to maintain said ion generator means at a higher pressure than said chamber whereby developer particles are substantially prevented from entering said ion generator means, a baffle overlying said ports through which said developer particles and said ions are introduced into said chamber, said baffle extending completely from one of said opposed sidewalls to the other of said opposed sidewalls whereby said ion cloud and said developer particle cloud initially meet and mix under said baffle, a grid electrode positioned between said latent electrostatic image-bearing surface and said baffle, and means to bias said grid electrode, said grid electrode being spaced from the latent electrostatic
  • the apparatus of claim 1 wherein said ion generator means is positioned within said chamber, said ion generator means having a housing having at least one corona emitting wire therein, that portion of said ion generator housing beneath said baffle and opposite said developer particle port at least partially defining the opposed sidewall of said chamber through which said cloud of ions is introduced into said chamber 4.
  • the apparatus of claim 1 further including means for introducing under pressure an ionizable gas to said ion generator means whereby the flow of said pressurized gas carries ions formed within said ion generator means through said ion generator ports into that portions of said chamber beneath said baffle.
  • said ion generator means comprises a housing having at least one corona emitting wire therein, and means to introduce under pressure an ionizable gas to said housing adjacent only the ends of said corona emitting wire, whereby the normal flow of the ionizable gas is along the length of said corona wire to about the midpoint thereof where the ion cloud exits through said ion generator ports into that portionof said chamber beneath said baffle.
  • the apparatus of claim 5 further including means to energize said corona wire.
  • the apparatus of claim 1 further including means for causing relative movement of said development chamber and said latent electrostatic image-bearing surface whereby a leak tight development chamber is defined.
  • baffle has an upper flat portion and downwardly depending side portions, whereby there is defined a zone within said chamber beneath said baffie where said ion cloud and said toner cloud initially meet and mix prior to movement of the charged toner cloud to the top of said chamber adjacent said latent electrostatic image-bearing surface.
  • the apparatus of claim 13 further including means to remove'unused toner from said chamber.
  • the apparatus of claim 1 further including a grid electrode adjacent the bottom wall of said chamber in those areas not directly beneath said baffle.
  • the apparatus of claim 1 further including means adjacent the walls defining said chamber for permitting the establishment of a pressure differential between the inside of said chamber and the outside of said chamber, said means assisting in the maintenance of the pressure differential established between said ion generator and said chamber.
  • said means comprises porous pads of limited porosity such that air but not developer particles can pass therethrough.
  • the apparatus of claim 1 further including delay means connected to said ion generator means and said developer cloud generator for enabling developer particles to be supplied to: said chamber before free ions.
  • An apparatus for developing a latent electrostatic image on a surface comprising a chamber having a pair of opposed sidewalls; means for supporting said surface with its latent electrostatic image-bearing side facing inwardly toward said chamber; a baffie extending completely from one of said opposed sidewalls to the other of said opposed sidewalls, said baffle being spaced from the remaining sidewalls whereby material introduced into said chamber under said baffle can move from beneath said baffle to the top of said development chamber; means for supplying a cloud of developer particles to said chamber through a port in one of said opposed sidewalls, said port being positioned in said sidewall beneath said baffle; ion generator means for supplying a cloud of ions to said chamber through at least one port in the other of said opposed sidewalls, all of said ion generator ports being positioned beneath said baffle, said ion generator means comprising a housing having at least one corona emitting means therein, means to energize said corona emitting means, means to introduce under pressure an ionizable
  • the apparatus of claim 24 further including means to cause said means for supplying a cloud of developer particles to said chamber to be pulsed at least once before said corona emitting means is energized.
  • baffle has an upper flat portion and outwardly and downwardly depending side portions, whereby there is defined a zone within said chamber beneath said baffle where said ion cloud and said developer cloud initially meet and mix prior to movement of the charged developer cloud to the top of said chamber adjacent said latent electrostatic image-bearing surface.
  • An apparatus for developing a latent electrostatic image on a surface comprising a chamber having a pair of opposed sidewalls, support means for supporting said surface with its latent electrostatic image-bearing side facing said chamber, means for supplying a cloud of charged developer particles to said chamber through a port in one of said opposed walls, a baffle overlying said port through which said developer particles are introduced into said chamber, said baffle extending completely from one of said opposed sidewalls to the other of said opposed sidewalls, a grid electrode positioned between said latent electrostatic image-bearing surface and said baffle, and means to bias said grid electrode to a desired potential and polarity, said grid electrode being spaced from the latent electrostatic image-bearing surface a distance sufficient to control the contrast and quality of the developed image.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dry Development In Electrophotography (AREA)
  • Electrophotography Using Other Than Carlson'S Method (AREA)
US874746A 1969-11-07 1969-11-07 Development apparatus for latent electrostatic images Expired - Lifetime US3640246A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US87474669A 1969-11-07 1969-11-07

Publications (1)

Publication Number Publication Date
US3640246A true US3640246A (en) 1972-02-08

Family

ID=25364478

Family Applications (1)

Application Number Title Priority Date Filing Date
US874746A Expired - Lifetime US3640246A (en) 1969-11-07 1969-11-07 Development apparatus for latent electrostatic images

Country Status (11)

Country Link
US (1) US3640246A (enrdf_load_stackoverflow)
JP (1) JPS5028179B1 (enrdf_load_stackoverflow)
AT (1) AT319044B (enrdf_load_stackoverflow)
BE (1) BE758632A (enrdf_load_stackoverflow)
CH (1) CH527453A (enrdf_load_stackoverflow)
DE (1) DE2054081A1 (enrdf_load_stackoverflow)
ES (1) ES385187A1 (enrdf_load_stackoverflow)
FR (1) FR2072347A5 (enrdf_load_stackoverflow)
GB (1) GB1336741A (enrdf_load_stackoverflow)
NL (1) NL7016048A (enrdf_load_stackoverflow)
SE (1) SE363411B (enrdf_load_stackoverflow)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3809012A (en) * 1972-11-24 1974-05-07 Xerox Corp Developer seal
US3861354A (en) * 1973-05-02 1975-01-21 Xonics Inc Electrostatic image developer
USB323666I5 (enrdf_load_stackoverflow) * 1973-01-15 1975-01-28
US3865079A (en) * 1973-08-27 1975-02-11 Gen Motors Corp Electrostatic fluid bed powder coating system
US3871328A (en) * 1972-04-13 1975-03-18 William P English Coating chamber
US3916826A (en) * 1973-09-18 1975-11-04 Electrostatic Equip Corp Electrostatic coating apparatus
US3953618A (en) * 1973-05-02 1976-04-27 Xonics, Inc. Electrostatic image developing process
US3974796A (en) * 1974-11-21 1976-08-17 Xerox Corporation Dual mode apparatus for developing latent electrostatic images
US4033292A (en) * 1974-11-21 1977-07-05 Xerox Corporation Apparatus for developing latent electrostatic images
US4038943A (en) * 1974-06-05 1977-08-02 Xerox Corporation Signal amplification by charging and illuminating a partially developed latent electrostatic image
FR2347986A1 (fr) * 1976-04-13 1977-11-10 Continental Group Perfectionnements apportes a l'application continue de poudre sur des substrats conducteurs et non conducteurs
US5093217A (en) * 1989-10-11 1992-03-03 Rca Thomson Licensing Corporation Apparatus and method for manufacturing a screen assembly for a crt utilizing a grid-developing electrode
US6489777B2 (en) * 2001-01-29 2002-12-03 Xerox Corporation System for purging electrostatic voltmeter modulator assembly

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6254321U (enrdf_load_stackoverflow) * 1985-09-04 1987-04-04

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2725304A (en) * 1951-08-31 1955-11-29 Haloid Co Process for developing an electrostatic latent image
US2824813A (en) * 1952-05-12 1958-02-25 Haloid Co Method for developing electrostatic latent images
US2842456A (en) * 1955-08-30 1958-07-08 Battelle Development Corp Process for developing an electrostatic image
US2859127A (en) * 1955-05-13 1958-11-04 Haloid Xerox Inc Process for developing electrostatic images
US2877132A (en) * 1955-02-18 1959-03-10 Haloid Xerox Inc Method for development of electrostatic images
US2914221A (en) * 1955-08-16 1959-11-24 Haloid Xerox Inc Aerosol bomb development
US3295440A (en) * 1964-05-27 1967-01-03 Continental Can Co Electrostatic printing method and apparatus employing corona discharge means
US3382360A (en) * 1965-09-10 1968-05-07 Xerox Corp Xerographic charging system having means for providing an air cushion between the charging device and the xerographic drum

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2725304A (en) * 1951-08-31 1955-11-29 Haloid Co Process for developing an electrostatic latent image
US2824813A (en) * 1952-05-12 1958-02-25 Haloid Co Method for developing electrostatic latent images
US2877132A (en) * 1955-02-18 1959-03-10 Haloid Xerox Inc Method for development of electrostatic images
US2859127A (en) * 1955-05-13 1958-11-04 Haloid Xerox Inc Process for developing electrostatic images
US2914221A (en) * 1955-08-16 1959-11-24 Haloid Xerox Inc Aerosol bomb development
US2842456A (en) * 1955-08-30 1958-07-08 Battelle Development Corp Process for developing an electrostatic image
US3295440A (en) * 1964-05-27 1967-01-03 Continental Can Co Electrostatic printing method and apparatus employing corona discharge means
US3382360A (en) * 1965-09-10 1968-05-07 Xerox Corp Xerographic charging system having means for providing an air cushion between the charging device and the xerographic drum

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3871328A (en) * 1972-04-13 1975-03-18 William P English Coating chamber
US3809012A (en) * 1972-11-24 1974-05-07 Xerox Corp Developer seal
USB323666I5 (enrdf_load_stackoverflow) * 1973-01-15 1975-01-28
US3924568A (en) * 1973-01-15 1975-12-09 Xerox Corp Apparatus for developing latent electrostatic images
US3861354A (en) * 1973-05-02 1975-01-21 Xonics Inc Electrostatic image developer
US3953618A (en) * 1973-05-02 1976-04-27 Xonics, Inc. Electrostatic image developing process
US3865079A (en) * 1973-08-27 1975-02-11 Gen Motors Corp Electrostatic fluid bed powder coating system
US3916826A (en) * 1973-09-18 1975-11-04 Electrostatic Equip Corp Electrostatic coating apparatus
US4101687A (en) * 1973-09-18 1978-07-18 Electrostatic Equipment Corporation Electrostatic coating method
US4038943A (en) * 1974-06-05 1977-08-02 Xerox Corporation Signal amplification by charging and illuminating a partially developed latent electrostatic image
US3974796A (en) * 1974-11-21 1976-08-17 Xerox Corporation Dual mode apparatus for developing latent electrostatic images
US4033292A (en) * 1974-11-21 1977-07-05 Xerox Corporation Apparatus for developing latent electrostatic images
FR2347986A1 (fr) * 1976-04-13 1977-11-10 Continental Group Perfectionnements apportes a l'application continue de poudre sur des substrats conducteurs et non conducteurs
US4088093A (en) * 1976-04-13 1978-05-09 Continental Can Company, Inc. Web coating and powder feed
US5093217A (en) * 1989-10-11 1992-03-03 Rca Thomson Licensing Corporation Apparatus and method for manufacturing a screen assembly for a crt utilizing a grid-developing electrode
US6489777B2 (en) * 2001-01-29 2002-12-03 Xerox Corporation System for purging electrostatic voltmeter modulator assembly

Also Published As

Publication number Publication date
FR2072347A5 (enrdf_load_stackoverflow) 1971-09-24
GB1336741A (en) 1973-11-07
JPS5028179B1 (enrdf_load_stackoverflow) 1975-09-12
CH527453A (de) 1972-08-31
DE2054081A1 (de) 1971-05-19
AT319044B (de) 1974-11-25
NL7016048A (enrdf_load_stackoverflow) 1971-05-11
BE758632A (fr) 1971-05-06
ES385187A1 (es) 1973-07-16
SU505386A3 (enrdf_load_stackoverflow) 1976-02-28
SE363411B (enrdf_load_stackoverflow) 1974-01-14

Similar Documents

Publication Publication Date Title
US3640246A (en) Development apparatus for latent electrostatic images
US3967891A (en) Imaging system for electrostatic reproduction machines
US2701764A (en) Electrophotographic apparatus and methods
US3382360A (en) Xerographic charging system having means for providing an air cushion between the charging device and the xerographic drum
US4398818A (en) Liquid toner fountain for the development of electrostatic images
US4361396A (en) Collecting apparatus for scattering toner
US3633544A (en) Turbocloud development
US3435802A (en) Electrographic liquid developing apparatus
US2842456A (en) Process for developing an electrostatic image
US3914609A (en) Signal amplification by illumination of a partially developed latent electrostatic image
US3646910A (en) Development apparatus for latent electrostatic images
US2859129A (en) Process for developing electrostatic images and apparatus therefor
PL79941B1 (enrdf_load_stackoverflow)
US3916828A (en) Apparatus for developing an electrostatic latent image on an electrophotographic film
US4021709A (en) Method and device for charging an electrophotographic photosensitive material
US4033292A (en) Apparatus for developing latent electrostatic images
US2918900A (en) Apparatus for xerographic development
US4575216A (en) Electrophotographic copying apparatus including transfer charge corona and shield
US3924568A (en) Apparatus for developing latent electrostatic images
US4038943A (en) Signal amplification by charging and illuminating a partially developed latent electrostatic image
US3974796A (en) Dual mode apparatus for developing latent electrostatic images
US2861543A (en) Apparatus for development of electrostatic image
US2811135A (en) Powder charging device
US2815734A (en) Apparatus for developing xerographic image
GB2150764A (en) Corona charging apparatus and method