US3881927A - Half tone development process for touchdown system in electrostatic imaging - Google Patents

Half tone development process for touchdown system in electrostatic imaging Download PDF

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Publication number
US3881927A
US3881927A US351221A US35122173A US3881927A US 3881927 A US3881927 A US 3881927A US 351221 A US351221 A US 351221A US 35122173 A US35122173 A US 35122173A US 3881927 A US3881927 A US 3881927A
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US
United States
Prior art keywords
toner
pattern
layer
donor
peaks
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
US351221A
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English (en)
Inventor
Joseph Fantuzzo
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
Priority to US351221A priority Critical patent/US3881927A/en
Priority to DE2403143A priority patent/DE2403143A1/de
Priority to CA192,843A priority patent/CA1068172A/fr
Priority to NL7404417A priority patent/NL7404417A/xx
Priority to GB1585874A priority patent/GB1419926A/en
Priority to JP49040848A priority patent/JPS5010143A/ja
Application granted granted Critical
Publication of US3881927A publication Critical patent/US3881927A/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
    • G03G15/0806—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
    • G03G15/0812—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 characterised by the developer regulating means, e.g. structure of doctor blade

Definitions

  • the pattern forming member has an electrode arranged in such a manner thereon that when a predetermined field is established between the electrode and the donor mem her, a predetermined pattern of peaks and valleys will be formed in the toner layer.
  • this patterned toner layer is presented to an electrostatic solid area latent image, the weakest charged portions of the latent image will attract only the toner from the portion of the layer which is closest thereto i. e., the peaks, thereby presenting a dot pattern development thereon.
  • the strongest charged portion of the electrostatic latent image will attract toner not only from the closet portion or peaks but will also attact toner from the valleys which will fully develop the image where the charge is strongest.
  • the charged pattern of the latent image which is between the weakest and strongest charge will attact a broadening pattern of toner from the peaks as well as from the valleys as the charge gets stronger.
  • a toner laden rotating donor member (which may be a roller or an endless belt) is located adjacent to a moving photoreceptive surface bearing a latent electrostatic image thereon.
  • the donor member is spaced from the photoreceptor so that a gap of about 2 to E microns exists between the toner layer surface and the photoreceptive surface.
  • the toner on the donor member carries a charge in polarity opposite to the polarity of the electrostatic latent image. As the donor member carries toner past the latent image, the toner is attracted from the donor to the image to develop the image.
  • FIG. 1 is a schematic view of a touchdown development system
  • FIG. 2 is a partial schematic view of a microfield donor and a commutating system therefor;
  • FIG. 3 is a view of a tonor layer pattern forming roll
  • FIG. 4 is a view of the donor roll with a toner layer thereon shown in section after a pattern has been formed therein.
  • a xerographic plate is in the form of a drum l0 which passes through stations A through E in the direction shown by the arrow.
  • the drum has a suitable photosensitive surface on which a latent electrostatic image can be formed.
  • the plurality of stations about the periphery of the drum which carry out the reproduction process are: charging station A. exposing station B, developing station C, transfer station D, and cleaning station E.
  • Stations A, B, D, and E represent conventional means for carrying out their respective functions and do not form a part of the present invention.
  • a corona charging means 12 places a uniform electrostatic charge on the photoconductive material.
  • a light pattern by a suitable exposing apparatus I4, is exposed onto the charged surface of drum I0.
  • the latent image thereby formed on the surface of the drum is developed by the application of toner particles at developing station C, which is described in greater detail below.
  • the toner is transferred to a sheet I6.
  • a corona charging device 18 is utilized in the normal way to facilitate transfer and fuser device 20 is provided to fuse the toner to sheet I6.
  • the drum ro- 2 tates through cleaning station E, comprising cleaning brush 22 which cleans residual toner particles from the drum 10.
  • the apparatus includes a donor member 24 at the developing station C which comprises an aluminum drum 26 and a dielectric layer 28 separating the drum 26 from a copper grid pattern 30.
  • a donor member 24 at the developing station C which comprises an aluminum drum 26 and a dielectric layer 28 separating the drum 26 from a copper grid pattern 30.
  • This programmed means comprises a segmented slip ring 37 and electrical contacts 38 which are shown schematically in FIG. 2.
  • a respective electrical lead 39 could be located inside of the donor member in electrical communication with a respective grid pattern while the other end of the respective electrical lead 39 is connected to a respective contact 38 which is in ring 37.
  • a voltage source 42 can supply the appropriate potential to each segment 40 of the slip ring.
  • the donor member 24 is rotatably mounted adjacent a toner reservoir 44 containing a supply of toner particles 46 in order that a portion of its periphery comes into contact with toner 46. This portion of the donor member 24 is properly biased to attract a layer 47 of toner particles thereto.
  • the donor roll is also located so as to provide a small gap of approximately 2-10 microns between the surface of drum l0 and the outer surface of a toner layer carried by donor roll 24. After a particular portion of the donor roll is rotated through the toner reservoir. that portion of the donor rotates past a corona charging device 48 which charges the toner particles 46 to the correct polarity. Thereafter the charged toner layer 47 is rotated past a toner layer pattern forming a gravure roll 50, whereby a peak and valley pattern is formed in the toner layer 47, and then the toner layer 47 is presented to the latent image to develop the same.
  • the donor roll is prepared for toner reloading by exposing the residual toner thereon to a neutralizing corona charge means 52 to make easier the removal of the residual toner by way of a cleaning brush 54 equipped with a vacuum means 56.
  • the gravure roll comprises a support drum 62 on which a copper film electrode 64 in the form of a grid pattern is fixed.
  • the support may be either a conductive or a dielectric material.
  • the roll 50 is so positioned that outer surface of the grid pattern 54 is spaced 2 to ID microns from the outer surface of the toner layer on the donor roll 24.
  • a voltage potential V is applied to the grid 64. That portion of the donor opposite the gravure roll 50 is programmed to be at ground potential.
  • the attractive field set up by the potential between the donor roll 24 and the grid 64 is pre determined so that a substantial amount of toner is removed from the toner layer and attracted to the grid 64 thereby leaving a predetermined pattern of individual peaks 66 surrounded by a continuous valley 68 in the toner particle layer as shown in FIG. 4.
  • the valleys 68 correspond to the toner removed by the grid electrode 64.
  • the weakest charged portion of the image will attract only the toner from the portion of the layer which is closest thereto, i.e., the peaks 66 thereby presenting a dot pattern development thereon.
  • the strongest charged portion of the electrostatic latent image will attract toner not only from the closest portion or peaks 66 but will also attract toner from the valleys 68 which will fully develop the image where the charge is strongest.
  • the charged pattern of the latent image which is between the weakest and strongest charge will attract a broadening pattern of toner from the peaks 66 as well as from the valleys 68 as the charge gets stronger. Thus, one can see that there will be many distinctive steps in grey scale rendition.
  • the developed image characteristics can be varied in accordance with the attractive field set up by the potential between the donor 24 and the gravure grid 64 which can be in a range between the electrostatic latent image background potential and the full potential on the photoreceptor.
  • the potential on the grid 64 can be in a range between +100 volts to +800 volts while the potential of the donor can be ground potential.
  • the lower potential range on the grid 64 is approached, less toner will be removed from the toner layer resulting in shallow and narrow valleys, while as the upper potential range on the grid 64 is approached, more toner will be removed from the toner layer resulting in deeper and wider valleys.
  • the gravure grid 64 when the potential of the gravure grid 64 is at background potential, the toner layer on the donor roll 24 is such that normal development takes place rather than half-tone development and therefore this potential on the gravure roll could be utilized when half-tone development is not desired.
  • the gravure roll will act as a roll means for removing a substantial amount of toner from the layer 47 which would otherwise be attracted to the background.
  • the gravure grid 64 is at a potential which is the full potential on the photoreceptor, only half-tone development will occur on the highest charged portions of the image. Thus, if only half-tone development without much distinction in grey scale rendition is desired, the gravure grid 64 would be set at full photoreceptor potential.
  • the distinctive steps in grey scale rendition obtained by the method of this invention can be changed by varying the potential on the gravure roll. Also, by changing the electrode pattern on the gravure roll, the distinctive steps of grey scale rendition may also be varied.
  • the electrode may be any type of pattern desired as long as it will form a pattern of peaks and valleys in the toner layer 47 on the donor roll 24.
  • the donor roll 24 is described as a microfield donor roll, any type donor roll may be utilized.
  • the key factor is that the donor roll must have a layer of toner thereon and that a field be set up between the donor roll and the gravure roll which will attract the particles to the gravure roll in such a manner that peaks and val leys are formed in the toner layer.
  • the photoreceptor 10, the donor roll 24, and the pattern-forming member 50 have each been described as rolls, any one of them or all of them may be in the form of a belt.
  • a method for developing latent electrostatic images carried by a substrate comprising the steps of loading a donor member with a layer of toner,
  • the method of claim 1 further including the step of rotating said donor member to carry out said loading, charging, pattern creating and developing steps in sequence.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dry Development In Electrophotography (AREA)
  • Developing For Electrophotography (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Electrophotography Using Other Than Carlson'S Method (AREA)
US351221A 1973-04-16 1973-04-16 Half tone development process for touchdown system in electrostatic imaging Expired - Lifetime US3881927A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US351221A US3881927A (en) 1973-04-16 1973-04-16 Half tone development process for touchdown system in electrostatic imaging
DE2403143A DE2403143A1 (de) 1973-04-16 1974-01-23 Kopiergeraet und verfahren zum bewirken unterschiedlicher stufen in der grauskalenwiedergabe
CA192,843A CA1068172A (fr) 1973-04-16 1974-02-18 Developpement demi-teintes pour systeme d'attenuation
NL7404417A NL7404417A (fr) 1973-04-16 1974-04-01
GB1585874A GB1419926A (en) 1973-04-16 1974-04-10 Half tone development of electrostatic latent images
JP49040848A JPS5010143A (fr) 1973-04-16 1974-04-10

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US351221A US3881927A (en) 1973-04-16 1973-04-16 Half tone development process for touchdown system in electrostatic imaging

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US48107974A Division 1974-06-20 1974-06-20

Publications (1)

Publication Number Publication Date
US3881927A true US3881927A (en) 1975-05-06

Family

ID=23380079

Family Applications (1)

Application Number Title Priority Date Filing Date
US351221A Expired - Lifetime US3881927A (en) 1973-04-16 1973-04-16 Half tone development process for touchdown system in electrostatic imaging

Country Status (6)

Country Link
US (1) US3881927A (fr)
JP (1) JPS5010143A (fr)
CA (1) CA1068172A (fr)
DE (1) DE2403143A1 (fr)
GB (1) GB1419926A (fr)
NL (1) NL7404417A (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3999515A (en) * 1975-02-03 1976-12-28 Xerox Corporation Self-spacing microfield donors
US4006981A (en) * 1974-06-20 1977-02-08 Xerox Corporation Half tone development for touchdown system
DE2800056A1 (de) * 1977-01-05 1978-07-13 Xerox Corp Reproduktionsmaschine, sowie elektrofotografische druckmaschine
US4136637A (en) * 1977-03-09 1979-01-30 Xerox Corporation Continuous contrast development system
US4271249A (en) * 1978-10-31 1981-06-02 Agfa-Gevaert N.V. Composition of matter and method for electrostatic image development
US4544264A (en) * 1984-05-17 1985-10-01 International Business Machines Corporation Fine line print enhancement
US20110036033A1 (en) * 2003-01-17 2011-02-17 Karine Luetgert Door skin, a method of etching a plate for forming a wood grain pattern in the door skin, and an etched plate formed therefrom
US8950139B2 (en) 2003-01-17 2015-02-10 Masonite Corporation Door skin, a method of etching a plate, and an etched plate formed therefrom

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5640862A (en) * 1979-09-11 1981-04-17 Canon Inc Developing device
US6653037B2 (en) 2000-11-20 2003-11-25 Ricoh Company, Ltd. Toner for developing latent electrostatic images, and image forming method and device

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3011473A (en) * 1958-05-01 1961-12-05 Xerox Corp Xerographic apparatus
US3152012A (en) * 1960-12-19 1964-10-06 Ibm Apparatus for the development of electrostatic images
US3203394A (en) * 1962-10-01 1965-08-31 Xerox Corp Xerographic development apparatus
US3559570A (en) * 1966-07-20 1971-02-02 Xerox Corp Method of preparing and using a gravure printing plate
US3635195A (en) * 1969-09-15 1972-01-18 Varian Associates Method and apparatus for producing halftone electrographic prints
US3696785A (en) * 1970-12-18 1972-10-10 Xerox Corp Development apparatus
US3696783A (en) * 1970-12-15 1972-10-10 Xerox Corp Automated touchdown developement system
US3731146A (en) * 1970-12-23 1973-05-01 Ibm Toner distribution process
US3739748A (en) * 1970-12-15 1973-06-19 Xerox Corp Donor for touchdown development
US3754963A (en) * 1970-12-23 1973-08-28 Ibm Surface for impression development in electrophotography
US3754962A (en) * 1970-12-21 1973-08-28 Ibm Development of electrostatic images
US3759222A (en) * 1971-03-04 1973-09-18 Xerox Corp Microfield donor with continuously reversing microfields

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3011473A (en) * 1958-05-01 1961-12-05 Xerox Corp Xerographic apparatus
US3152012A (en) * 1960-12-19 1964-10-06 Ibm Apparatus for the development of electrostatic images
US3203394A (en) * 1962-10-01 1965-08-31 Xerox Corp Xerographic development apparatus
US3559570A (en) * 1966-07-20 1971-02-02 Xerox Corp Method of preparing and using a gravure printing plate
US3635195A (en) * 1969-09-15 1972-01-18 Varian Associates Method and apparatus for producing halftone electrographic prints
US3696783A (en) * 1970-12-15 1972-10-10 Xerox Corp Automated touchdown developement system
US3739748A (en) * 1970-12-15 1973-06-19 Xerox Corp Donor for touchdown development
US3696785A (en) * 1970-12-18 1972-10-10 Xerox Corp Development apparatus
US3754962A (en) * 1970-12-21 1973-08-28 Ibm Development of electrostatic images
US3731146A (en) * 1970-12-23 1973-05-01 Ibm Toner distribution process
US3754963A (en) * 1970-12-23 1973-08-28 Ibm Surface for impression development in electrophotography
US3759222A (en) * 1971-03-04 1973-09-18 Xerox Corp Microfield donor with continuously reversing microfields

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4006981A (en) * 1974-06-20 1977-02-08 Xerox Corporation Half tone development for touchdown system
US3999515A (en) * 1975-02-03 1976-12-28 Xerox Corporation Self-spacing microfield donors
DE2800056A1 (de) * 1977-01-05 1978-07-13 Xerox Corp Reproduktionsmaschine, sowie elektrofotografische druckmaschine
US4136637A (en) * 1977-03-09 1979-01-30 Xerox Corporation Continuous contrast development system
US4271249A (en) * 1978-10-31 1981-06-02 Agfa-Gevaert N.V. Composition of matter and method for electrostatic image development
US4544264A (en) * 1984-05-17 1985-10-01 International Business Machines Corporation Fine line print enhancement
US8950139B2 (en) 2003-01-17 2015-02-10 Masonite Corporation Door skin, a method of etching a plate, and an etched plate formed therefrom
US8697226B2 (en) * 2003-01-17 2014-04-15 Masonite Corporation Door skin, a method of etching a plate for forming a wood grain pattern in the door skin, and an etched plate formed therefrom
US20110036033A1 (en) * 2003-01-17 2011-02-17 Karine Luetgert Door skin, a method of etching a plate for forming a wood grain pattern in the door skin, and an etched plate formed therefrom
US8993094B2 (en) 2003-01-17 2015-03-31 Masonite Corporation Door skin, a method of etching a plate for forming a wood grain pattern in the door skin, and an etched plate formed therefrom
US9416585B2 (en) 2003-01-17 2016-08-16 Masonite Corporation Door skin, a method of etching a plate, and an etched plate formed therefrom
US9719288B2 (en) 2003-01-17 2017-08-01 Masonite Corporation Door skin, a method of etching a plate, and an etched plate formed therefrom
US9976339B2 (en) 2003-01-17 2018-05-22 Masonite Corporation Method of molding a door skin and an etched plate for the same
US10047556B2 (en) 2003-01-17 2018-08-14 Masonite Corporation Door skin, a method of etching a plate, and an etched plate formed therefrom
US10316579B2 (en) 2003-01-17 2019-06-11 Masonite Corporation Stained and stainable construction components
US10597931B2 (en) 2003-01-17 2020-03-24 Masonite Corporation Etched plate for forming a molded construction component
US10648225B2 (en) 2003-01-17 2020-05-12 Masonite Corporation Door skin, method of etching plate for forming wood grain pattern in door skin, and etched plate formed therefrom
US10914115B2 (en) 2003-01-17 2021-02-09 Masonite Corporation Door skin, a method of etching a plate, and an etched plate formed therefrom

Also Published As

Publication number Publication date
GB1419926A (en) 1975-12-31
JPS5010143A (fr) 1975-02-01
CA1068172A (fr) 1979-12-18
NL7404417A (fr) 1974-10-18
DE2403143A1 (de) 1974-10-31

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