US3257224A - Method and apparatus for developing electrostatic images - Google Patents
Method and apparatus for developing electrostatic images Download PDFInfo
- Publication number
- US3257224A US3257224A US247025A US24702562A US3257224A US 3257224 A US3257224 A US 3257224A US 247025 A US247025 A US 247025A US 24702562 A US24702562 A US 24702562A US 3257224 A US3257224 A US 3257224A
- Authority
- US
- United States
- Prior art keywords
- roller
- developer
- trough
- toner
- magnetic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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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
- G03G15/09—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer using magnetic brush
- G03G15/0921—Details concerning the magnetic brush roller structure, e.g. magnet configuration
Definitions
- the developers normally used in electrophotography consist of a mixture of finely divided resinous toner and a carrier for the toner of somewhat larger particle size than the toner.
- the carrier is often of magnetizable material, e.g. iron filings, in order to enable the developer to be applied with the aid of a rotating magnetic roller to the surface of a latent electrostatic image.
- the magnetic roller which may be a permanent magnet or may be magnetized by an electric current, dip into developer powder contained in a trough beneath the roller.
- the toner is attracted electrostatically from the magnet to the photoconductive coating of the electrophotographic material and a visible image is formed.
- the developer, depleted in toner is returned to the trough as the magnetic roller rotates.
- the iron filings always come to rest at the same place, namely near the point at which renewed magnetization of the poles occurs so that the mixing operation in the trough, which can be carried out at a limited speed only and which is intended to load the iron filings with new toner, cannot take place sufiiciently rapidly.
- the roller therefore continually picks up the toner-depleted iron filings which have just been dropped as a result of the demagnetization.
- the present invention provides an apparatus for developing latent electrostatic images comprising a trough to contain a developer mixture of iron filings and toner powder, an agitator in the trough, an electromagnetically excited iron roller for picking up developer from the trough and transferring it to the electrophotographic material to be developed, the iron roller being made of up of rotor plates having a number of windings to which exciting current is supplied intermittently, being cut off once in every revolution of the roller and a covering of synthetic plastic 3,257,224 Patented June 21, 1956 material, and a deflector plate which coacts with the portion of the roller traveling away from the electrophotographic material and towards the developer contained in the trough to deflect towards the wall of the trough developer shed by the roller while the current is cut off.
- the laminations of the roller consists of relatively thin soft iron sheets placed side by side with layers 'of insulating material between them.
- the shape of these plates corresponds to the cross section of the intended roller. If the notches provided for the windings are even in number, particularly good results can be obtained.
- the covering on the roller mayconsist of any suitable insulating plastic which is solid at normal temperatures.
- suitable plastics are thermoplastics, such as polyolefins, e.g. polyethylene and polypropylene, polyvinyl compounds such as polyvinyl chloride, polyamides and polyesters.
- thermosetting resins e.g. phenolformaldehyde resins.
- plastics such as those used for insulating purposes in transformers; they are described, for example, in the handbook of Messrs. lSchgamm, Lackund, Wegrik AG, Elektro-Isolierac e.
- the plastic coating can be applied by placing the magnetic roller in a mold, the gap between the inner Walls of mold and the surface of the magnetic roller being greater than the thickness of the plastic coating which is to be produced on the surface of the roller.
- the intermediate spaces are now filled with a substance which contains unhardened components of a resin mixture together with a hardener. The whole is then allowed to 'stand for 20-30 hours, during which time the plastic hardens completely. After removing the roller from the mold, it is advantageous for'the surface of the plastic coating to be evened and smoothed by turning.
- the plastic covering may also be applied to the roller by painting on a mixture of the plastic substance and a hardener.
- the thickness of the painted coating is advantageously considerably greater than the thickness finally required.
- the surface of the plastic coating is again finished by turning and polishing.
- Plastic coatings, particularly thermoplastic coatings can also be applied to the roller surface in the form of ready made foils by wrapping and, where necessary, fusing.
- the thickness of the plastic coating on the surface of the electromagnetic roller is generally between 0.2 and 1.0 mm. preferably 0.4-0.5 mm., but lesser or greater thicknesses can also be successfully used.
- the surface of the plastic coating on the magnetic roller may be made electrically conducting and may be provided with a bias voltage with respect to the surface of the photoconductive layer of the electrophotographic material or it may be grounded. This is particularly advantageous in the case of the development of latent electrostatic images which, because of inadequate exposure, have a residual charge in the image-free parts.
- the surface can, for example, be made conductive by treatment with a dispersion of silver particles in a suitable dispersion agent, e.g. the so-called Leitsilber (conducting silver), or it can be .coated with metal. Good results are also obtained by the application of a thin metal foil to the roller.
- a suitable dispersion agent e.g. the so-called Leitsilber (conducting silver)
- Leitsilber conducting silver
- the deflector plate extends over the whole width of the electromagnetic roller.
- the distance of the deflector plate from the surface of the roller should be kept as small as possible.
- the length of the surface of the deflector plate over which the toner-depleted carrierruns should be as great as possible.
- the deflector plate should discharge the carrier near to the wall of the trough.
- the deflector plate can be joined underneath with the normally used securing devices to the wall of the vessel.
- the apparatus may include a container for toner powder adjacent the trough and means for periodically delivering measured quantities of toner powder from the container to the trough.
- FIGURE 1 is a transverse section through the developing apparatus
- FIGURE 2 is a plan view
- FIGURE 3 is a longitudinal section through the developing apparatus
- FIGURE 4 shows the current supply member in crosssection
- FIGURE 4a shows the current supply member in plan view.
- the apparatus includes an electromagnetically excited roller 1 having a shaft 2 which is journaled in bearings 3 and 4 and is driven by the gears 5, 6 and 7.
- the windings 9 of the roller 1 receive current from a source, not shown, of direct current via individual slip rings 10. 1
- the roller 1 has twelve grooves 9' containing six separate windings which are excited by means of six slip rings 10 which coact with the brushes 26.
- the roller 1 also has a coating 11 of synthetic plastic material. Between points 12 and 13, the slip rings 10 are provided with means for interrupting the current.
- the roller rotates anticlockwise as viewed in FIGURE 4 and, as soon as the windings 9 have passed the point 13, they are deprived of current.
- the developer carried by the roller is then dropped off and is deflected by a deflector plate 14 to the outer edge of the developer trough.
- the discarded developer works its way very slowly back from the outer edge of the developer trough 14' to the agitator 15 in the trough and is taken up by the agitator and, after intensive mixing, passed to the point 12, at which magnetization of the roller recommences, and is there taken up by the roller.
- the plastic coating 11 on the magnetic roller 1 ensures that after the current has been switched off at the point 13 the developer will not remain attracted by residual magnetism.
- the trough is replenished with toner in a simple manner and without dust by the following mechanism:
- a container 17 (FIG. 3) contains a certain quantityof toner for purposes of replenishment.
- the trough is replenished with toner from the container 17 by dosing plungers 18.
- End plates 19 on the plungers 18 normally close the feed opening 20 in the wall of the container 17 and the plungers carry sealing sleeves 21.
- the plungers, which are fitted with return springs 24, are actuated by rocker arms 22 from a motordriven eccentric 23, which is driven at a speed appropriate to requirements.
- the toner in the container 17 is agitated by a vane 25 which is vibrated by a rocker magnet.
- Apparatus for developing latent electrostatic images comprising a trough adapted to contain a developer having a magnetic component, a rotatable electrically magnetizable roller mounted in the trough, the roller having a plurality of separate windings and an insulating layer on the roller surface, means for supplying and interrupting an electric current to at least one of the windings during rotation of the roller to thereby successively magnetize and demagnetize portions of the roller surface, and defleeting means mounted adjacent the roller.
- Apparatus according to claim 1 including a container adapted to contain toner mounted adjacent the trough and means for delivering measured quantities of toner to the trough.
- a process for applying a developer to a latent electrostatic image which comprises electrically generating a magnetic field in portions of a surface of a rotatable applicator submerged in a body of developer having a magnetic component, rotating the said portions of the surface carrying developer thereon into contact with the latent electrostatic image, rotating the said portions of the surface out of contact with the electrostatic image and interrupting the electric current, thereby eliminating the magnetic field from said portions of said surface, and passing excess developer from said portions of said surface back into the body of developer at a point remote from the initial position of the developer in the body.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Magnetic Brush Developing In Electrophotography (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DEK0045522 | 1961-12-27 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3257224A true US3257224A (en) | 1966-06-21 |
Family
ID=7223876
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US247025A Expired - Lifetime US3257224A (en) | 1961-12-27 | 1962-12-26 | Method and apparatus for developing electrostatic images |
Country Status (4)
Country | Link |
---|---|
US (1) | US3257224A (ja) |
BE (1) | BE626526A (ja) |
GB (1) | GB976998A (ja) |
NL (1) | NL286833A (ja) |
Cited By (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3318284A (en) * | 1964-01-30 | 1967-05-09 | Hitachi Ltd | Apparatus for developing electrostatic images of records |
US3574301A (en) * | 1969-04-02 | 1971-04-13 | Xerox Corp | Developing apparatus |
US3996892A (en) * | 1975-02-24 | 1976-12-14 | Xerox Corporation | Spatially programmable electrode-type roll for electrostatographic processors and the like |
US3998185A (en) * | 1975-02-03 | 1976-12-21 | Xerox Corporation | Microfield donors with toner agitation and the methods for their manufacture |
US4017648A (en) * | 1975-02-03 | 1977-04-12 | Xerox Corporation | Toner agitation through microfield donor |
US4086873A (en) * | 1974-07-09 | 1978-05-02 | Konishiroku Photo Industry Co., Ltd. | Electrophotographic developing device incorporating a developing electrode having an insulation layer on its surface |
US5063412A (en) * | 1990-09-26 | 1991-11-05 | Xerox Corporation | Development apparatus using an electromagnet to prevent development in the non-operative mode |
US5289240A (en) * | 1993-05-20 | 1994-02-22 | Xerox Corporation | Scavengeless developer unit with electroded donor roll |
US5360940A (en) * | 1993-07-14 | 1994-11-01 | Xerox Corporation | Scavengeless two component development with an electroded development roll |
EP0691586A1 (en) | 1994-07-05 | 1996-01-10 | Xerox Corporation | Development apparatus having an adjustable width development nip |
US5500969A (en) * | 1994-10-24 | 1996-03-26 | Xerox Corporation | Dual polarity commutated roll elctrostatic cleaner with acoustic transfer assist |
US5570169A (en) * | 1995-09-25 | 1996-10-29 | Xerox Corporation | Donor rolls with modular commutation |
US5589917A (en) * | 1995-09-25 | 1996-12-31 | Xerox Corporation | Donor rolls with magnetically coupled (Transformer) commutation |
US5592271A (en) * | 1996-01-11 | 1997-01-07 | Xerox Corporation | Donor rolls with capacitively cushioned commutation |
US5594534A (en) * | 1996-01-11 | 1997-01-14 | Xerox Corporation | Electroded doner roll structure incorporating resistive network |
US5600418A (en) * | 1995-09-25 | 1997-02-04 | Xerox Corporation | Donor rolls with exterior commutation |
US5614995A (en) * | 1995-09-05 | 1997-03-25 | Xerox Corporation | Electroded donor roll having robust commutator contacts |
US5745827A (en) * | 1997-03-31 | 1998-04-28 | Xerox Corporation | Bundled steel wire SED communicator secondary cores |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3687106A (en) * | 1969-07-11 | 1972-08-29 | Xerox Corp | Donor apparatus and method |
Citations (26)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US404465A (en) * | 1889-06-04 | Electric motor | ||
US500400A (en) * | 1893-06-27 | Philip lange | ||
US673980A (en) * | 1900-06-22 | 1901-05-14 | Harry M Mcnelly | Electromagnet-motor. |
US1048223A (en) * | 1908-11-28 | 1912-12-24 | Heinrich Stein | Electromagnetic separator. |
US1177981A (en) * | 1914-05-14 | 1916-04-04 | Parvin Wright | Magnetic separator. |
US1362072A (en) * | 1917-11-17 | 1920-12-14 | Arnold Horace Wade | Magnetic ore-separator |
US1371301A (en) * | 1920-08-21 | 1921-03-15 | Converse Henry | Combined feeder and magnetic separator |
US1449371A (en) * | 1919-09-15 | 1923-03-27 | Vincent G Apple | Method of constructing armatures for dynamo-electric machines |
US2449021A (en) * | 1942-06-08 | 1948-09-07 | Hoover Co | Dynamoelectric machine |
US2711249A (en) * | 1954-05-20 | 1955-06-21 | Fur Unternehmungen Der Eisen U | Drum magnet separator |
US2779306A (en) * | 1955-03-25 | 1957-01-29 | Ibm | Electroscopic toner metering device |
US2832311A (en) * | 1956-01-10 | 1958-04-29 | Haloid Co | Apparatus for development of electrostatic images |
US2844489A (en) * | 1957-12-20 | 1958-07-22 | Knapsack Ag | Fluidized bed coating process |
US2896101A (en) * | 1957-05-03 | 1959-07-21 | United Aircraft Corp | Differential tachometer |
US2904000A (en) * | 1957-05-15 | 1959-09-15 | Century Geophysical Corp | Magnetic-brush developer |
US2956487A (en) * | 1955-03-23 | 1960-10-18 | Rca Corp | Electrostatic printing |
US2975758A (en) * | 1958-03-13 | 1961-03-21 | Haloid Xerox Inc | Apparatus for developing electrostatic images |
US2992733A (en) * | 1957-10-09 | 1961-07-18 | Indiana General Corp | Magnetic pulley and permanent magnet therefor |
US3003462A (en) * | 1957-01-18 | 1961-10-10 | Bruning Charles Co Inc | Apparatus for applying developer powder to photo-conductive insulating sheets |
US3028266A (en) * | 1957-11-04 | 1962-04-03 | Everett P Larsh | Method and apparatus for impregnating motor windings and motor stator |
US3028708A (en) * | 1960-01-08 | 1962-04-10 | Columbus M Vaughan | Blast cleaning machines |
US3040704A (en) * | 1957-04-16 | 1962-06-26 | Rca Corp | Apparatus for developing electrostatic printing |
US3081737A (en) * | 1961-03-01 | 1963-03-19 | Gen Aniline & Film Corp | Xerographic apparatus for applying ferromagnetic powder |
US3088386A (en) * | 1959-11-16 | 1963-05-07 | American Photocopy Equip Co | Electrophotographic photocopy machine |
US3098765A (en) * | 1959-03-16 | 1963-07-23 | Robertson Photo Mechanix Inc | Xerographic brush |
US3152924A (en) * | 1961-05-24 | 1964-10-13 | Robertson Photo Mechanix Inc | Xerographic brush |
-
0
- NL NL286833D patent/NL286833A/xx unknown
- BE BE626526D patent/BE626526A/xx unknown
-
1962
- 1962-12-18 GB GB47823/62A patent/GB976998A/en not_active Expired
- 1962-12-26 US US247025A patent/US3257224A/en not_active Expired - Lifetime
Patent Citations (26)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US500400A (en) * | 1893-06-27 | Philip lange | ||
US404465A (en) * | 1889-06-04 | Electric motor | ||
US673980A (en) * | 1900-06-22 | 1901-05-14 | Harry M Mcnelly | Electromagnet-motor. |
US1048223A (en) * | 1908-11-28 | 1912-12-24 | Heinrich Stein | Electromagnetic separator. |
US1177981A (en) * | 1914-05-14 | 1916-04-04 | Parvin Wright | Magnetic separator. |
US1362072A (en) * | 1917-11-17 | 1920-12-14 | Arnold Horace Wade | Magnetic ore-separator |
US1449371A (en) * | 1919-09-15 | 1923-03-27 | Vincent G Apple | Method of constructing armatures for dynamo-electric machines |
US1371301A (en) * | 1920-08-21 | 1921-03-15 | Converse Henry | Combined feeder and magnetic separator |
US2449021A (en) * | 1942-06-08 | 1948-09-07 | Hoover Co | Dynamoelectric machine |
US2711249A (en) * | 1954-05-20 | 1955-06-21 | Fur Unternehmungen Der Eisen U | Drum magnet separator |
US2956487A (en) * | 1955-03-23 | 1960-10-18 | Rca Corp | Electrostatic printing |
US2779306A (en) * | 1955-03-25 | 1957-01-29 | Ibm | Electroscopic toner metering device |
US2832311A (en) * | 1956-01-10 | 1958-04-29 | Haloid Co | Apparatus for development of electrostatic images |
US3003462A (en) * | 1957-01-18 | 1961-10-10 | Bruning Charles Co Inc | Apparatus for applying developer powder to photo-conductive insulating sheets |
US3040704A (en) * | 1957-04-16 | 1962-06-26 | Rca Corp | Apparatus for developing electrostatic printing |
US2896101A (en) * | 1957-05-03 | 1959-07-21 | United Aircraft Corp | Differential tachometer |
US2904000A (en) * | 1957-05-15 | 1959-09-15 | Century Geophysical Corp | Magnetic-brush developer |
US2992733A (en) * | 1957-10-09 | 1961-07-18 | Indiana General Corp | Magnetic pulley and permanent magnet therefor |
US3028266A (en) * | 1957-11-04 | 1962-04-03 | Everett P Larsh | Method and apparatus for impregnating motor windings and motor stator |
US2844489A (en) * | 1957-12-20 | 1958-07-22 | Knapsack Ag | Fluidized bed coating process |
US2975758A (en) * | 1958-03-13 | 1961-03-21 | Haloid Xerox Inc | Apparatus for developing electrostatic images |
US3098765A (en) * | 1959-03-16 | 1963-07-23 | Robertson Photo Mechanix Inc | Xerographic brush |
US3088386A (en) * | 1959-11-16 | 1963-05-07 | American Photocopy Equip Co | Electrophotographic photocopy machine |
US3028708A (en) * | 1960-01-08 | 1962-04-10 | Columbus M Vaughan | Blast cleaning machines |
US3081737A (en) * | 1961-03-01 | 1963-03-19 | Gen Aniline & Film Corp | Xerographic apparatus for applying ferromagnetic powder |
US3152924A (en) * | 1961-05-24 | 1964-10-13 | Robertson Photo Mechanix Inc | Xerographic brush |
Cited By (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3318284A (en) * | 1964-01-30 | 1967-05-09 | Hitachi Ltd | Apparatus for developing electrostatic images of records |
US3574301A (en) * | 1969-04-02 | 1971-04-13 | Xerox Corp | Developing apparatus |
US4086873A (en) * | 1974-07-09 | 1978-05-02 | Konishiroku Photo Industry Co., Ltd. | Electrophotographic developing device incorporating a developing electrode having an insulation layer on its surface |
US3998185A (en) * | 1975-02-03 | 1976-12-21 | Xerox Corporation | Microfield donors with toner agitation and the methods for their manufacture |
US4017648A (en) * | 1975-02-03 | 1977-04-12 | Xerox Corporation | Toner agitation through microfield donor |
US3996892A (en) * | 1975-02-24 | 1976-12-14 | Xerox Corporation | Spatially programmable electrode-type roll for electrostatographic processors and the like |
US5063412A (en) * | 1990-09-26 | 1991-11-05 | Xerox Corporation | Development apparatus using an electromagnet to prevent development in the non-operative mode |
US5289240A (en) * | 1993-05-20 | 1994-02-22 | Xerox Corporation | Scavengeless developer unit with electroded donor roll |
US5360940A (en) * | 1993-07-14 | 1994-11-01 | Xerox Corporation | Scavengeless two component development with an electroded development roll |
US5491538A (en) * | 1994-07-05 | 1996-02-13 | Xerox Corporation | Development apparatus having an adjustable width development nip |
EP0691586A1 (en) | 1994-07-05 | 1996-01-10 | Xerox Corporation | Development apparatus having an adjustable width development nip |
US5500969A (en) * | 1994-10-24 | 1996-03-26 | Xerox Corporation | Dual polarity commutated roll elctrostatic cleaner with acoustic transfer assist |
EP0709751A2 (en) | 1994-10-24 | 1996-05-01 | Xerox Corporation | Apparatus for cleaning particles from a surface |
US5614995A (en) * | 1995-09-05 | 1997-03-25 | Xerox Corporation | Electroded donor roll having robust commutator contacts |
US5570169A (en) * | 1995-09-25 | 1996-10-29 | Xerox Corporation | Donor rolls with modular commutation |
US5589917A (en) * | 1995-09-25 | 1996-12-31 | Xerox Corporation | Donor rolls with magnetically coupled (Transformer) commutation |
US5600418A (en) * | 1995-09-25 | 1997-02-04 | Xerox Corporation | Donor rolls with exterior commutation |
US5592271A (en) * | 1996-01-11 | 1997-01-07 | Xerox Corporation | Donor rolls with capacitively cushioned commutation |
US5594534A (en) * | 1996-01-11 | 1997-01-14 | Xerox Corporation | Electroded doner roll structure incorporating resistive network |
EP0785485A2 (en) | 1996-01-11 | 1997-07-23 | Xerox Corporation | Electrodes donor roll structures incorporating resistive networks |
EP0786707A2 (en) | 1996-01-11 | 1997-07-30 | Xerox Corporation | Donor rolls with capacitively cushioned commutation |
US5745827A (en) * | 1997-03-31 | 1998-04-28 | Xerox Corporation | Bundled steel wire SED communicator secondary cores |
Also Published As
Publication number | Publication date |
---|---|
GB976998A (en) | 1964-12-02 |
BE626526A (ja) | |
NL286833A (ja) |
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