US3793205A - Chargeless developer - Google Patents

Chargeless developer Download PDF

Info

Publication number
US3793205A
US3793205A US00169547A US3793205DA US3793205A US 3793205 A US3793205 A US 3793205A US 00169547 A US00169547 A US 00169547A US 3793205D A US3793205D A US 3793205DA US 3793205 A US3793205 A US 3793205A
Authority
US
United States
Prior art keywords
developer
pigment
grams
areas
oil
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
US00169547A
Other languages
English (en)
Inventor
K Metcalfe
W Lowe
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.)
COMMONWEALTH AU
COMMW
Original Assignee
COMMW
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
Priority claimed from AU32926/63A external-priority patent/AU284779B2/en
Application filed by COMMW filed Critical COMMW
Application granted granted Critical
Publication of US3793205A publication Critical patent/US3793205A/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
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/12—Developers with toner particles in liquid developer mixtures

Definitions

  • a surface charge is placed on the aforementioned layer by a corona discharge.
  • the electrostatic image is formed by exposing areas of the layer to light. Development is achieved by attracting charged particles to the unexposed areas which still retain a surface charge.
  • the layer is activated by light or X-rays and absorption of light or X-rays and activation by them is greater near the surface of the layer, the creation of charge carriers near the surface results in a field outside the layer, the direction of which is consistent with a layer of positively charged particles at the irradiated surface.
  • An opposite field is also detectable at the opposite surface of the layer, that is where radiation leaves the layer.
  • the electrons and holes created near the irradiated surface will diffuse away from these maximum absorption layers to regions of lower carrier concentration.
  • one carrier may diffuse more than the other. If this occurs then the fixed carrier will have a greater concentration near the irradiated surface.
  • the holes In the case of zinc oxide, the holes have very low mobility and only the electrons diffuse away from the surface. This results in a potential gradient or hill similar to the junction potential of n and p type doped semiconductors, that is, the same resultant field as produced by a layer of positive ions on the surface of the layer.
  • this diffusion field opposes the deposition of positively charged particles and gives the image a clean background.
  • the dark-rested areas are designated negative because they attract positively charged particles and the irradiated areas are designated positive because they attract negative particles and we consider that the development of negative areas may be due to adsorption we find an explanation for the background density which occurs when an attempt is made to develop the positive areas. This background may be due to surface adsorption in the absence of a repulsion or shielding mechanism.
  • the final image-forming pigment is the particle with the greatest sensitivity, provided that it is present in sufficient concentration relative to other particle concentrations.
  • a concentrated particle suspension may develop but later be displaced by a second particle of the same or opposite polarity which was not concentrated enough to gain first place on the layer, but by virtue of its sensitivity and relative concentration, replaced the deposited pigment either in the same area or in undeveloped areas by depositing in these areas as the previously developed image moves from the surface and into suspension.
  • a developer of the required polarity is used in a concentrated form in order to achieve greater image density.
  • this high concentration gives background, particularly in the reverse system where the negative areas may be developing partly by adsorption.
  • a second developer medium of opposite polarity is now incorporated in the suspension and if it is sensitive but of low concentration it will act as a low intensity developer for the areas which form the background of the visual image by virtue of its sensitivity.
  • the low concentration will stop it from developing to such an extent as to decrease the visual (developed) image area density.
  • the background charge is still satisfied because to achieve pigment sensitivity it is coated with a partly or fully soluble polymer and this polymer can satisfy the background adsorption or charge requirements to the exclusion of the visible or opaque pigment.
  • the dark adapted areas and illuminated areas have been designated negative and positive for ease of description, the development occurs as a difference between the fields from these areas and some reference level so that if a layer is exposed to radiation in discreet steps, development of the negative areas decreases with these steps.
  • development of the positive areas which increases with radiation up to saturation, does not require a certain constant value of illumination to erase the negative areas.
  • FIG, 1 shows the relationship between illumination and deposit.
  • the improvement consists in an improved developer which develops areas of a zinc oxide layer or other photoconductive layer to a denser image by virtue of a control layer placed on the pigment particle, which develops an even denser image by placing a soluble dispersing agent in the carrier liquid which has the property of keeping the suspended coated particles apart without interfering with their behaviour except to make them more sensitive because they are more finely divided; and which gives increased density and a clean background by having in the carrier liquid a second developer of opposite polarity to the major developing particle and of less concentration or a soluble control agent which is opposite in electrical effect on particles to the first control layer and which satisfies the background areas which are required to be kept undeveloped by pigment.
  • the improved developer can be said to consist of five parts:-
  • the carrier liquid usually an insulating vehicle such as an hydrocarbon which is commonly used in liquid electrophotographic developers.
  • a pigment preferably of the same polarity as the desired final developing particle, that is, opposite in charge sign to the area to be developed.
  • a control coating which will make the pigment particle oppositely charged with respect to the surface to be developed, or increase its charge if it is already charged in the desired polarity.
  • D A dispersing agent which will aid the dispersion of the mixture of B and C in the carrier A and create a finer suspension.
  • D can be a control agent for B in which case C is not used
  • E Separate from the aforesaid pigment, a dispersion of opposite charge polarity to the resultant particle charge after B and C are combined; or a control agent of opposite (polarity) effect to the one which has been placed on the pigment, and which will exist dissolved in the carrier liquid if the particle is already coated, and act as a developer of opposite sign.
  • C is stated as Cp for positive or Cn for negative E, is hereafter sometimes referred to as Cn or Cp respectively.
  • the vegetable and animal oils listed turn the fol- I lowing pigments negative or more negative.
  • Oils Pigments to form a negative particle with these oils Oils Pigments to form a negative particle with these oils.
  • Linseed oil Sunflower seed oil safflower oil Carbon Black (Coates) Tung oil Vivid Magenta Tall oil Brilliant Green (Coates) Peanut oil Rose Red Maize oil Carbon Black (Kohinoor) Soya oil Carbon Black, Excelsior Poppyseed oil Oiticics Oil Lanoline Castor Oil Boiled Linseed Oil 2.
  • the following mineral type oils and resins form positive particles when coated on the listed pigments.
  • the following long oil alkyd resins can be used to disperse the product of B and C without decreasing their effectiveness as developers.
  • polymer system is composed of four parts and for a reverse developer to develop positive areas the role of each is as follows:
  • the carrier liquid-insulating medium C
  • the charge forming control agent e.g. a Vegetable oil
  • the dispersing agent e.g. a long oil alkyd resin
  • TABTLET T i Effect of sequence of wetting on polarity.
  • This pigment can be turned positive if the sequence and relative quantities of Cp and Cn are varied as the above results are not the only ones possible. It will be noted that the positive and negative control agents have opposite charge forming characteristics.
  • the pigment used in this example can be formed negative or positive depending on whether the negative or the positive control agent was first placed on the pigment. Many pigments respond in this way but this is one which can be changed either way and which will remain in the desired state. In many cases the pigment itself is strongly charged, opposed the tendency to move its charge in l gram Pigment (B):
  • Cp B.P. Viscostatic Motor oil 2 grams Dispersing agent (D): Long oil alkyd resin, e.g.
  • B.P. Viscostatic Motor being a positive control agent: Oil, British Petroleum Brilliant Green. for example the opposite direction, and slowly reverted to its natural polarity but with marked decrease in chargeless response. If the pigment has a natural polarity and the control agent is of the type to move the charge to greater magnitude in that direction, then the best results are obtained.
  • TABLE 11 illustrates a negative pigment and shows that maximum chargeless response and low background density obtained only when the correct andcomplete sequence is used.
  • both the pigment particles and the shielding medium be kept mobile, and this is achieved by the dispersing agent which lessens attraction between these substances in spite of their pposite charge and therefore even if the oppositely charged components coelesce, it will be obvious that Kohinoor" Carbon Black Sunflower Seed Oil Long oil alkyd resin such as Super Beckosoi i352 Reichold Corp.
  • Viscostatic Motor Oil lOO grams 300 grams 200 grams 500 grams Ear firiiia'ii'iii ingredients, and disperse grams of concentrate in 100 grams of carrier liquid (A) which is Shellite.
  • the background cleaner (Cp) required can be made by dispersing 10 grams of BF. Viscostatic Motor oil in Shellite and this is used as a predip, either before or after exposure and with or without drying by evaporation.
  • the reflection density readings for this developer when combined part by part is as follows:
  • the present invention includes with the developer particles, a substance of opposite polarity, but of lesser effect due to quantity or other factors, which has the effect of driving down more developer particles on to the appropriate image area and also of shielding the background areas against contact with pigment particles.
  • both surfaces cannot be developed fully in relation to the charges existing and therefore the background developing medium is chosen to develop to a lesser amount while the developer itself is arranged to deposit in a much greater amount.
  • Brillant Green pigment (Brilliant Vivid Green 3458, Smith Reichold Colours Ltd, Sydney Australia): 100 grams Sunflower seed oil (Meggitts Ltd. Australia): 300
  • the pigment was wetted with the sunflower seed oil and milled to form a paste.
  • EXAMPLE 2 A developer paste was prepared by mixing together the following materials in the order given:
  • Super Becltosol 1352 resin an alkyd resin supplied by Smith Reichold Colours Ltd. Sydney Australia
  • a suitable cleaning agent was found to be a dispersion of blow bitumen (petroleum type) comprising 1 part by weight of bitumen in 100 parts of Alsol 35/ 140: 500 grams Bitumen of suitable type was obtainable from B.P. Australia Limited as solid bitumen.
  • the paste which was obtained by mixing these materials constitutes a devel oper concentrate and was then diluted with a suitable hydrocarbon liquid or other insulating liquid such as a silicone oil or fluid to form a developer.
  • X4 is a solvent marketed by Shell Chemicals Ltd., and contains 1 per ent aromatics and has a boiling range of 55 to 72 C.
  • EXAMPLE 3 A developer paste was made from the following materials mixed together in the given order:
  • Irgalite Fast Brilliant Blue GLSM 100 grams Maize oil (Me'ggitts Ltd., Sydney, Australia): 300
  • Shell lubricating oil, S.A.E. 20 300 grams
  • the resultant developer concentrate was then diluted with a suitable insulating liquid such as Shellsol T, a product of the Shell Chemicals Co. Sydney, Australia, in the proportions of 1 part of concentrate to parts of liquid diluent-Shellsol T is a hydrocarbon solvent having a boiling range of 180 to 206 C. and a flash point of F.
  • a suitable insulating liquid such as Shellsol T, a product of the Shell Chemicals Co. Sydney, Australia
  • EXAMPLE 4 A developer paste was made from the following materials mixed together in the following order:
  • Paralac 10 oil modified alkyd resin (Imperial Chemical Industries of Australia and New Zealand): 250 grams A background cleaning agent was then added and milled into the mixture to form a paste, for example:
  • Lucite 2046 in toluol comprising 25 per cent of Lucite by weight: 25 grams
  • the resultant concentrate was then diluted with a suitable insulating liquid such as X4 solvent, a product of the Shell Chemicals Co., Australia, in the proportions of 1 part of concentrate by weight to 200 parts of'X4.
  • Lucite is a copolymer of n-butyl and isobutyl methacrylate and is a product of the DuPont Corporation, United States of America.
  • EXAMPLE 5 A developer concentrate was made from the following materials mixed together in the order given below:
  • Liquid paraffin oil WM 6 (HP. Australia Limited):
  • the resultant paste was a developer concentrate which was then dispersed in a suitable insulating liquid, such for instance as Isopar H, in the proportions of 1 part of concentrate to 200 parts of Isopar H by volume.
  • Isopar H is an isoparaffinic solvent with a high boiling range containing zero aromatics supplied by Esso Standard Oil (Aust.) Limited.
  • EXAMPLE 6 A developer concentrate was made from the following materials mixed together in the following order:
  • Brillfast Vivid Green pigment C3248 (Smith Reichold Colours Limited, Australia): 90 grams B.P. Viscostatic motor oil, product of B.P. Australia Limited, containing polyester resins and zinc dithiophosphate as a surfactant: 450 grams These materials were milled together to form a paste to which was subsequently added the following material:
  • Dispersing agent long oil alkyd resin, Rhodene L42/70 (Product of Polymer Corporation Limited, Australia): 180 grams The following material was added subsequently to act as a background cleaner in relation to the foregoing materials of this example:
  • Oiticica oil (Meggitts Limited): 270 grams The final concentrate was added to an insulating liquid to form a developer; a typicalcarrier liquid for this purpose being Shellsol T or lsopar H.
  • a typicalcarrier liquid for this purpose being Shellsol T or lsopar H.
  • Other liquids which may be used include perchloroethylene, the fluorinated-chlorinat'ed hydrocarbons such as the Freons and Arctons, cyclohexane, deodorized kerosene and the like.
  • An improved developer for use in chargeless developing of a xerographic surface having thereon a latent electrical image of a first polarity and a background outside of said image and of a relatively different polarity, said developer consisting essentially of a hydrocarbon liquid carrier having an electrical resistivlty sufficiently high and a dielectric constant sufficiently low to avoid destruction of said latent image, pigment particles suspended in and possessing an electrical charge in the said carrier liquid and mobile therein to form a developer medium for the image, a control agent coating the surface of the pigment particles to form controlled pigment particles and control the polarity thereof and to increase the charge of the controlled particles in a direction opposite to that of the image on the surface to be developed, a dispersing agent for the pigment particles in the carrier liquid to enhance dispersion of the controlled pigment particles in said carrier, and a second developer medium of a polarity opposite to the polarity of the controlled pigment particles dispersed in the said liquid carrier, said second developer medium being such that it does not wet the pigment, particles and is therefore mobile independently of the particles

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Liquid Developers In Electrophotography (AREA)
US00169547A 1963-07-11 1971-08-05 Chargeless developer Expired - Lifetime US3793205A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AU32926/63A AU284779B2 (en) 1963-07-11 An improved developer for use where electrophotographic material hasnot been electrically charged prior to light exposure

Publications (1)

Publication Number Publication Date
US3793205A true US3793205A (en) 1974-02-19

Family

ID=3720393

Family Applications (1)

Application Number Title Priority Date Filing Date
US00169547A Expired - Lifetime US3793205A (en) 1963-07-11 1971-08-05 Chargeless developer

Country Status (4)

Country Link
US (1) US3793205A (enrdf_load_stackoverflow)
BE (1) BE650423A (enrdf_load_stackoverflow)
GB (1) GB1070748A (enrdf_load_stackoverflow)
NL (1) NL148715B (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4830945A (en) * 1988-05-23 1989-05-16 Xerox Corporation Liquid electrophotographic developer comprising oppositely charged toner particles and dyes of different colors
US4877698A (en) * 1988-05-23 1989-10-31 Xerox Corporation Electrophotographic process for generating two-color images using liquid developer
US4880720A (en) * 1988-05-23 1989-11-14 Xerox Corporation Liquid developer compositions
US4947201A (en) * 1988-06-06 1990-08-07 Spectrum Sciences Imaging system
US4966824A (en) * 1988-06-06 1990-10-30 Spectrum Sciences Liquid toner composition containing two different charge directors
US5012300A (en) * 1988-06-06 1991-04-30 Spectrum Sciences B.V. Two-color imaging system and process
US5108866A (en) * 1988-06-06 1992-04-28 Spectrum Sciences B.V. Process for preparing liquid toner composition
US5121164A (en) * 1988-06-06 1992-06-09 Spectrum Sciences B.V. Method for maintaining a liquid composition
US5164778A (en) * 1989-11-02 1992-11-17 Ricoh Company, Ltd. Image forming apparatus with ozone detection and deodorizer
US20050180766A1 (en) * 2003-12-29 2005-08-18 Shin Joong-Gwang Developing method of liquid type electrophotographic image forming device

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3032432A (en) * 1957-08-05 1962-05-01 Commw Of Australia Controlled tone development for electrophotography
US3078231A (en) * 1959-05-13 1963-02-19 Commw Of Australia Controlled developer for use in electro-photography and electro-radiography
US3081263A (en) * 1956-12-21 1963-03-12 Secretary Of The Dept Of Suppl Precipitation of particulate or molecular materials in electrostatic developing
US3300410A (en) * 1961-03-13 1967-01-24 Australia Res Lab Conductive liquid developer for xerographic images
US3383316A (en) * 1963-10-28 1968-05-14 Australia Res Lab Liquid electrophotographic developer containing isocyanate compounds
US3391015A (en) * 1964-04-27 1968-07-02 Harris Intertype Corp Liquid development of electrostatic images with carbon black and a solid organic pigment
US3392018A (en) * 1962-04-11 1968-07-09 Commw Of Australia Xerochemical development of electrostatic images

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3081263A (en) * 1956-12-21 1963-03-12 Secretary Of The Dept Of Suppl Precipitation of particulate or molecular materials in electrostatic developing
US3032432A (en) * 1957-08-05 1962-05-01 Commw Of Australia Controlled tone development for electrophotography
US3078231A (en) * 1959-05-13 1963-02-19 Commw Of Australia Controlled developer for use in electro-photography and electro-radiography
US3300410A (en) * 1961-03-13 1967-01-24 Australia Res Lab Conductive liquid developer for xerographic images
US3392018A (en) * 1962-04-11 1968-07-09 Commw Of Australia Xerochemical development of electrostatic images
US3383316A (en) * 1963-10-28 1968-05-14 Australia Res Lab Liquid electrophotographic developer containing isocyanate compounds
US3391015A (en) * 1964-04-27 1968-07-02 Harris Intertype Corp Liquid development of electrostatic images with carbon black and a solid organic pigment

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4830945A (en) * 1988-05-23 1989-05-16 Xerox Corporation Liquid electrophotographic developer comprising oppositely charged toner particles and dyes of different colors
US4877698A (en) * 1988-05-23 1989-10-31 Xerox Corporation Electrophotographic process for generating two-color images using liquid developer
US4880720A (en) * 1988-05-23 1989-11-14 Xerox Corporation Liquid developer compositions
US4947201A (en) * 1988-06-06 1990-08-07 Spectrum Sciences Imaging system
US4966824A (en) * 1988-06-06 1990-10-30 Spectrum Sciences Liquid toner composition containing two different charge directors
US5012300A (en) * 1988-06-06 1991-04-30 Spectrum Sciences B.V. Two-color imaging system and process
US5108866A (en) * 1988-06-06 1992-04-28 Spectrum Sciences B.V. Process for preparing liquid toner composition
US5121164A (en) * 1988-06-06 1992-06-09 Spectrum Sciences B.V. Method for maintaining a liquid composition
US5164778A (en) * 1989-11-02 1992-11-17 Ricoh Company, Ltd. Image forming apparatus with ozone detection and deodorizer
US20050180766A1 (en) * 2003-12-29 2005-08-18 Shin Joong-Gwang Developing method of liquid type electrophotographic image forming device

Also Published As

Publication number Publication date
GB1070748A (en) 1967-06-01
DE1472913B2 (de) 1972-07-06
BE650423A (enrdf_load_stackoverflow) 1964-11-03
NL6407923A (enrdf_load_stackoverflow) 1965-01-12
NL148715B (nl) 1976-02-16
DE1472913A1 (de) 1969-03-27

Similar Documents

Publication Publication Date Title
US3793205A (en) Chargeless developer
US5266435A (en) Liquid toners containing charge directors and components for stabilizing their electrical properties
US3053688A (en) Electrostatic printing
US3038799A (en) Method of reversing the image in xerography
US3772199A (en) Liquid developer used for electrophotography
CA2064756C (en) Humidity tolerant charge director compositions
US3438904A (en) Liquid toner
JP3489032B2 (ja) 静電写真用の帯電制御剤を含有する液体現像剤
US3150976A (en) Electrostatic printing
US4877698A (en) Electrophotographic process for generating two-color images using liquid developer
US3968044A (en) Milled liquid developer
US3918966A (en) Liquid development of an electrical image in which a pulsating field is employed
US3512965A (en) Electroprinting method
US3909433A (en) Liquid electrophotographic developing compositions
US3770485A (en) Method for liquid-developing an electrostatic image
US3874896A (en) Reversible developer for electrostatic latent imaging method
US3507794A (en) Electrostatic photography systems
US3507679A (en) Controlled polarity liquid developer
US3804658A (en) Method of improving development of xerographic images
US3850830A (en) Liquid developer containing extender body particles
US3885960A (en) Method of development of liquid electrostatic images using an hydrophobic barrier liquid
US4880720A (en) Liquid developer compositions
JPS6260705B2 (enrdf_load_stackoverflow)
US3625897A (en) Liquid developing agent for electrophotography
US5206107A (en) Siloxane surfactants as liquid developer additives