US3923506A - Photoelectric and electrophotographic pigments comprising derivatives of condensed polycyclic aromatic hydrocarbon aldehydes - Google Patents

Photoelectric and electrophotographic pigments comprising derivatives of condensed polycyclic aromatic hydrocarbon aldehydes Download PDF

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Publication number
US3923506A
US3923506A US337787A US33778773A US3923506A US 3923506 A US3923506 A US 3923506A US 337787 A US337787 A US 337787A US 33778773 A US33778773 A US 33778773A US 3923506 A US3923506 A US 3923506A
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pigment
pigments
suspension
image
polycyclic aromatic
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John Alf Bergfjord
Steven James Grammatica
Richard William Radler
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Xerox Corp
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Xerox Corp
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Priority to US508967A priority patent/US3915702A/en
Priority to US508966A priority patent/US3922169A/en
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G17/00—Electrographic processes using patterns other than charge patterns, e.g. an electric conductivity pattern; Processes involving a migration, e.g. photoelectrophoresis, photoelectrosolography; Processes involving a selective transfer, e.g. electrophoto-adhesive processes; Apparatus essentially involving a single such process
    • G03G17/04—Electrographic processes using patterns other than charge patterns, e.g. an electric conductivity pattern; Processes involving a migration, e.g. photoelectrophoresis, photoelectrosolography; Processes involving a selective transfer, e.g. electrophoto-adhesive processes; Apparatus essentially involving a single such process using photoelectrophoresis
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/02—Charge-receiving layers
    • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
    • G03G5/06—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being organic
    • G03G5/0601—Acyclic or carbocyclic compounds
    • G03G5/0612—Acyclic or carbocyclic compounds containing nitrogen
    • G03G5/0616—Hydrazines; Hydrazones

Definitions

  • variously colored light absorbing particles are suspended in a non-conductive liquid carrier.
  • the suspension is placed between electrodes, subjected to a potential difference and exposed to an image.
  • selective particle migration takes place in image configuration, providing a visible image at one or both of the electrodes.
  • An essential component of the system is the suspended particles which must be electrically photosensitive and which apparently undergo a net change in charge polarity upon exposure to activating electromagnetic radiation through interaction with one of the electrodes.
  • particles of a single color are used, producing a single colored image equivalent to conventional black'and-white photography.
  • the images are produced in natural color because mixtures of particles of two or more different colors which are each sensitive to light of a specific wavelength or narrow range of wavelengths are used.
  • Particles used in this system must have both intense pure colors and be highly photosensitive.
  • the pigments of the prior an often lack the purity and brilliance of color, the high degree of photosensitivity, and the preferred correlation between the peak spectral response and peak photosensitivity necessary for use in such a system.
  • R is selected from the group consisting of: H and s si R is selected from the group consisting of: CH;,, C H lower alkyl containing 3-8 carbon atoms,
  • R is selected from the group consisting of: H. OH, CH OCH C H OC H COCH CO CH COC H CO C H N0 CN, SO NH SO NHC H, Cl, F. Br, I; and
  • n is a positive integer from 1-3.
  • These compounds may be prepared by reacting a monosubstituted condensed polycyclic aromatic aldehyde with an amine or ketone containing active hydro gen, as will be hereinafter disclosed.
  • the preferred aldehydes are the monosubstituted carboxaldehydes of pyrene, anthracene, phenanthrene, chrysene, tetracene and tetraphene.
  • the reaction products are formed as the result of an aldol type condensation involving the aromatic aldehyde and a suitable ketone, or a condensation reaction involving the aromatic aldehyde and a primary aliphatic or aromatic amine.
  • the compounds produced by the above reactions havethe common characteristic of a brilliant, intense yellow or orange color and are readily dispersible in common solvents. They are surprisingly effective when used in monochromatic or polychromatic electrophoretic imaging systems, as well as in preparing electrophotographic plates as will be hereinafter defined.
  • a transparent electrode generally designated 1 which, in this exemplary instance, is made up of a layer of optically transparent glass 2 overcoated with a thin optically transparent layer 3 of tin oxide, commercially available under the name NESA glass.
  • This electrode will hereafter be referred to as the injecting electrode.
  • Coated on the surface of injecting electrode 1 is a thin layer 4 of finely divided photosensitive particles dispersed in an insulating liquid carrier.
  • photosensitive for the purposes of this application, refers to the properties of a particles which, once attracted to the injecting electrode, will migrate away from it under the influence of an applied electric field when it is exposed to actinic electromagnetic radiation.
  • Liquid suspension 4 may also contain a sensitizer and- /or a binder for the pigment particles which is at least partially soluble in the suspending or carrier liquid as will be explained in greater detail below.
  • Adjacent to the liquid suspension 4 is a second electrode 5, hereinafter called the fblocking electrode" which is connected to one side of the potential source 6 through a switch 7.
  • the opposite side of potential source 6 is connected to the injecting electrode 1 so that when switch 7 is closed, an electric field is applied across the liquid suspension 4 between electrodes 1 and 5.
  • Electrode 5 is made in the form of a roller having a conductive central core 11 connected to the potential source 6. The core is covered with a layer of a blocking electrode material 12, which may be Baryta paper. The pigment suspension is exposed to the image to be reproduced while a potential is applied across the blocking and injecting electrodes by closing switch 7. Roller 5 is caused to roll across the top surface of injecting electrode 1 with switch 7 closed during the period of image exposure.
  • This light exposure causes exposed pigment particles originally attracted to electrode l to migrate through the liquid and adhere to the surface of the blocking electrode, leaving behind a pigment image on the injecting electrode surface which is a duplicate of the original transparency 9.
  • the relatively volatile carrier liquid evaporates off, leaving behind the pigment image.
  • This pigment image may then be fixed in place as, for example, by placing a lamination over its top surface or by virtue of a dissolved binder material in the carrier liquid such as paraffin wax or other suitable binder that comes out of solution as the carrier liquid evaporates. About 3 to 6 percent by weight of paraffin binder in the carrier has been found to produce good results.
  • the carrier liquid itself may be liquefied paraffin wax or other suitable binder.
  • the pigment image remaining on the injecting electrode may be transferred to another surface and fixed thereon.
  • this system can produce either monochromatic or polychromatic images depending upon the type and number of pigments suspended in the carrier liquid and the color of light to which this suspension is exposed in the process.
  • any suitable insulating liquid may be used as the carrier for the pigment particles in the system.
  • Typical carrier liquids are decane, dodecane, N-tetradecane, paraffin, beeswax or other thermoplastic materials, Sohio Odorless Solvent 3440 or 3454 (kerosene factions available from Standard Oil Company of Ohio) and Isopar G (a long chain saturated aliphatic hydrocarbon available from Humble Oil Company of New Jersey). Good quality images have been produced with voltages ranging from 300 to 5,000 volts in the apparatus of the FIGURE.
  • particles of a single composition are dispersed in the carrier liquid and exposed to a black-and-white image.
  • a single color results, corresponding to conventional black-and-white photography.
  • the particles are selected so that those of different colors respond to different wavelengths in the visible spectrum corresponding to their principal absorption bands.
  • the pigments should be selected so that their spectral response curves do not have substantial overlap, thus allowing for color separation and subtractive multicolor image formation.
  • the particle dispersion should include cyan colored particles sensitive mainly to red light, magenta particles sensitive mainly to green light, and yellow colored particles sensitive mainly to blue light. When mixed together in a carrier liquid, these particles produce a black appearing liquid.
  • the particles When one or more of the particles are caused to migrate from base electrode 1 toward an upper electrode, they leave behind particles which produce a color equivalent to the color of the impinging light.
  • red light exposure causes the cyan-colored pigment to migrate, leaving behind the magenta and yellow pigments which combine to produce red in the final image.
  • blue and green colors are reproduced by removal of yellow and magenta, respectively.
  • white light impinges upon the mix all pigments migrate, leaving behind the color of the white or transparent substrate. No exposure leaves behind all pigments which combine to produce a black image.
  • This is an ideal technique of subtractive color imaging in that the particles are not only each composed of a single component, but in addition, they perform the dual functions of final image colorant and photosensitive medium.
  • the particle size of the pigments should be less than about 10 microns, preferably within the range of about 0.0l to 5 microns.
  • Any suitable different-colored photosensitive pig- Com und in accordance with Formula I may be ment particles having the desired spectral responses prepared b den ing 3-pyrer1e carboxaldehyde with may be used with the pigments of this invention to form ketones f h f l a partial suspension in a carrier liquid for color imaging.
  • Typical cyan and magenta pigments include those 5 s described, for example, in U.S. Pat. Nos. 3,383,993 and 3,384,566.
  • the magenta particles may comprise watch- R CH C R ing Red B, the barium salt of l-(methyl--chloro-azol 2 benzcne-2'-sulfonic acid)-2-hydroxy-3-napthoic acid, Cl.
  • the preferred alde- Compounds corresponding to Formula II may be prehydes are the monosubstituted carboxaldehydes of pared by catalytic reduction or hydrogenation of the condensed polycyclic aromatic hydrocarbons containalpha, beta, unsaturated ketones corresponding to Foring from about 14 to about 20 carbon atoms such as pymula I by techniques well known in the art:
  • These hydrocarbons may also contain prepared by an amine condensation reaction of pyreneorganic or inorganic substituent groups which do not 3-carboxaldehydewith pheny'lhydrazine:
  • derivatives of pyrene may be prepared by reacting l 1 C 2 6 5 a 1 CHNNHC H H O pyrene carboxaldehyde in Aldo] type condensation with the appropriate ketone having active hydrogen at (b) [Z] CHO+H NNHC H (NO [Z] the a carbon.
  • the plate employed is roughly 3 inches square and is exposed with a light intensity of 8,000 foot candles as measured on the uncoated NESA glass surface. Unless otherwise indicated, about 13.5 percent by weight of the indicated pigments in each example are suspended in Sohio Odorless Solvent 3454 and the magnitude of the applied potential is 2,500 volts. All pigments which have a relatively large particle size as made are ground in a ball mill for 48 hours to reduce their size to provide a more stable dispersion which improves the resolution of the final images. The exposure is made with a 3,200K lamp through a positive transparency.
  • Example I is suspended in about 100 parts of solvent and the images developed as in Example I. A good orange image was produced on the negative NESA with a slight image on the positive NESA.
  • Example II is suspended'in parts of solvent and the images developed as in Example I. A good orange image was produced on both the negative and the positive NESA.-'
  • c11 cn ccn CH2 is suspended in 100 parts of solvent and the images developed as in Example I. A good yellow image was produced on the negative NESA, with a slight image on the positive NESA.
  • Example II is suspended in 100 parts of solvent and the images de veloped as in Example I. A good yellow-orange image was produced on both the negative and positive NESA.
  • Example VI Example VII 1n the following example, a suspension comprising three colored pigments is made by dispersing the pigments in finely divided form in Sohio Odorless Solvent 3440 so that the pigments constitute 8 percent by weight of the mixture.
  • the mixture may be referred to as a trimix.
  • the trimixes are individually tested by coating them on the NESA glass plate and exposing them as in Example 1 above, except that a multicolor transparency is used in place of the black-and-white transparency.
  • a multicolored image is projected on the plate as the roller electrode moves across the surface thereof.
  • a Baryta paper blocking electrode is employed and the roller is held at a positive potential of about 2,500 volts. The roller is passed over the plate, after which the quality of the image upon the plate is evaluated as to the image density and color purity.
  • EXAMPLE IX A trimix ink was prepared using 1 part yellow compound of Example VI, 1 part Monolite Fast Blue GS, and 2 parts watching Red B. CI No. 15865. When exposed, as discussed above, the trimix produced a full color image on the negative NESA corresponding to the original with good color separation and excellent density characteristics.
  • the class of pig ments of the present invention having the above general formula are suitable for use in electrophoretic imaging processes. Sinch their photographic speed, density characteristics and color characteristics vary, a
  • mixture of the particular pigments may be preferred for' specific uses. Some characteristics of the pigments may be improved by particular purification processes, recrystallization processes and dye sensitization.
  • compositions of the general formula given above are also useful in xerographic imaging systems.
  • xerographic plates may be produced by coating a relatively conductive substrate, e.g., aluminum or paper, with a dispersion of particles of the photosensitive pigment of the above general formula in a resin binder.
  • the pigment-resin layer may also be cast as a self-supporting film.
  • the plate formed may be both with or without an overcoating on the photoconductive layer.
  • the photosensitive pigment-resin photoconductive layer may be used in the formation of multilayer sandwich configurations adjacent a dielectric layer, similar to that shown by Golovin, et al., in the publication entitled A New Electrophotographic Process, Effected by Means at Combined Electret Layers, Doklady Akad. NaukSSR vol. 129, No. 5, pp. 1008-1011, November-December 1961.
  • Suitable materials for this purpose include aluminum,
  • a typical overcoating is bichromated shellac.
  • any suitable organic binder or resin may be used in combination with the pigment to prepare the photoconductive layer of this invention.
  • the resin used in the present invention should be more resistive than about 10 and preferably more than 10 ohms per centimeter under the conditions of xerographic use.
  • Typical resins include thermoplastics such as polyvinyl chloride, polyvinylacetates, polyvinylidene chloride, polystyrene, polybutadiene, polymethacrylates, polyacrylics, polyacrilonitrile, silicone resins, chlorinated rubber, and mixtures and copolymers thereof where applicable; and thermosetting resins such as epoxy resins including halogenated epoxy and phenoxy resins, phenolics, epoxyphenolic copolymers, epoxy ureaformaldehyde copolymers, epoxy melamine formaldehyde copolymers and mixtures thereof where applicable.
  • Other typical resins are epoxy esters, vinyl epoxy resins, tall-oil modified epoxies, and mixtures thereof where applicable.
  • any other suitable resin may be used if desired.
  • other binders such as paraffin and mineral waxes may be used if desired.
  • the pigments may be incorporated in the dissolved or melted binder resin by way suitable means such as strong shear agitation, preferably with simultaneous grinding. These include ball milling, roller milling, sand milling, ultrasonic agitation, high-speed blending and any desirable combination of these methods. Any suitable range of pigment-resin ratios may be used.
  • the pigment-resin-solvent slurry (or the pigmentresin melt) may be applied to the conductive substrate by any of the well known painting or coating methods, including spraying, flow coating, knife coating, electrocoating, Mayer bar drawdown, dip coating, reverse foil coating, etc. Spraying in an electric field may be preferred for the smoothest finish and dip coating for convenience in the laboratory.
  • the setting, drying and/or curing steps for these plates are generally similar to those recommended for films of the particular binder used for other painting applications.
  • pigment-epoxy plates may be cured by adding a cross-linking agent and stoving according to approximately the same schedule as other baking enamels made with the same resins and similar pigments for painting applications.
  • a very desirable aspect of these pigments is that they are stable against chemical decomposition at the temperatures normally used for a wide variety of bakeon enamels, and therefore, may be incorporated in very hard glossy photoconductive coatings, similar to automotive or kitchen appliance resin finishes.
  • the thickness of the photoconductive films may be varied from about 1 to about 100 microns, depending on their required individual purpose.
  • Self-supporting films for example, cannot usually be manufactured in thicknesses thinner than about 10 microns, and they are easiest to handle and use in the 15 to micron range.
  • Coatings on the other hand, are preferably formed in the 5 to 30 micron range. For certain compositions and purposes, it is desirable to provide an overcoating; this should usually not exceed the thickness of the photoconductive coating, and preferably not above one-quarter of the latter. Any suitable overcoating material may be used, such as bichromated shellac.
  • a xerographic plate for use as in the following example is prepared as follows: mixtures using specific pigments and resin binders are prepared by ball milling the pigment and a solution of a resinous binder and one or more solvents until the pigment is well dispersed. This is done by adding the desired parts of the pigment to the desired parts of resin solution in a suitable mixing vessel. A quantity of /8 inch steel balls are added and the vessel is rotated for approximately one-half hour in order to obtain a homogeneous dispersion. The cooled slurry is applied onto an aluminum substrate with a wire drawdown rod and force dried in an oven for about 3 minutes at about 100C. The coated sheets are dark rested for about 1 hour and then tested.
  • the plate is tested as follows.
  • the plate is charged negative by corona discharge to about 400 volts and exposed to a light and shadow image.
  • the plate is cascade developed using Xerox 1824 developer.
  • the powder image produced on the plate corresponds to the projected image.
  • the developed image may be then either fused to the plate or may be electrostatically transferred to a receiving sheet and there fused. Where the image is transferred, the plate may be then cleaned or residual toner and may be reused as by the above described process.
  • EXAMPLE X The xerographic plate is prepared by initially mixing about 2 parts of Lucite 2042, an ethylmethacrylate polymer, about 18 parts benzene, and about 1 part of the pigment of Example VII. This mixture is coated onto an aluminum substrate to a thickness of about 8 microns and cured. The plate is then charged, exposed for about 45 seconds to a'light and shadow image using a Simmons Omega D3 enlarger equipped with a tungsten light source operating at 2950K color temperature (illumination level incident on the palte is 2.8 foot candles as measured with a Weston Illumination Meter Model No. 756), and developed as above described. The image produced is heat fused directly onto the plate. The image produced was found to be satisfactory.
  • pigment compositions of this invention may be dye sensitized, if desired, or may be mixed with other photosensitive materials, both organic and inorganic.
  • An electrophoretic imaging suspension comprising a electrically insulating liquid carrier medium having dispersed therein an electrically photosensitive pigment composition comprising a mixture of pigments, at least a first of said pigments selected from the group consisting of cyan, magneta, or mixtures thereof.

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US337787A 1973-03-05 1973-03-05 Photoelectric and electrophotographic pigments comprising derivatives of condensed polycyclic aromatic hydrocarbon aldehydes Expired - Lifetime US3923506A (en)

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US337787A US3923506A (en) 1973-03-05 1973-03-05 Photoelectric and electrophotographic pigments comprising derivatives of condensed polycyclic aromatic hydrocarbon aldehydes
US508967A US3915702A (en) 1973-03-05 1974-09-25 Photoelectric and electrophotographic pigments comprising derivatives of condensed polycyclic aromatic hydrocarbon aldehydes
US508966A US3922169A (en) 1973-03-05 1974-09-25 Photoelectric and electrophotographic pigments comprising derivatives of condensed polycyclic aromatic hydrocarbon aldehydes

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4105447A (en) * 1975-07-14 1978-08-08 Eastman Kodak Company Photoconductive insulating compositions including polyaryl hydrocarbon photoconductors
US4332948A (en) * 1979-05-25 1982-06-01 Ricoh Company, Ltd. Novel hydrazone compounds and process for preparing the same
US4621156A (en) * 1979-10-29 1986-11-04 Polaroid Corporation Optical filter agents and photographic products and processes containing same
US5041648A (en) * 1989-02-10 1991-08-20 Basf Aktiengesellschaft Phenylhydrazones of β-ionone
US8187359B2 (en) 2006-03-24 2012-05-29 Mesabi Nugget Llc Granulated metallic iron superior in rust resistance and method for producing the same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109232485A (zh) * 2018-11-07 2019-01-18 陕西科技大学 一种含芘基查尔酮衍生物及其制备方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB380511A (en) * 1931-06-18 1932-09-19 Richard Francis Collinson Improvements in or relating to wireless apparatus
US2851495A (en) * 1955-07-06 1958-09-09 Hoechst Ag Di (amidinophenyl) hydrazones
GB930988A (en) * 1958-07-03 1963-07-10 Ozalid Co Ltd Improvements in and relating to electrophotographic reproduction materials
US3246983A (en) * 1959-04-08 1966-04-19 Azoplate Corp Electrophotographic reproduction process
US3414650A (en) * 1964-07-08 1968-12-03 Gaf Corp Sunscreening methods
US3510419A (en) * 1964-07-23 1970-05-05 Zerox Corp Photoelectrophoretic imaging method
US3546085A (en) * 1967-01-30 1970-12-08 Xerox Corp Photoelectrophoretic imaging process and suspension

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB380511A (en) * 1931-06-18 1932-09-19 Richard Francis Collinson Improvements in or relating to wireless apparatus
US2851495A (en) * 1955-07-06 1958-09-09 Hoechst Ag Di (amidinophenyl) hydrazones
GB930988A (en) * 1958-07-03 1963-07-10 Ozalid Co Ltd Improvements in and relating to electrophotographic reproduction materials
US3246983A (en) * 1959-04-08 1966-04-19 Azoplate Corp Electrophotographic reproduction process
US3414650A (en) * 1964-07-08 1968-12-03 Gaf Corp Sunscreening methods
US3510419A (en) * 1964-07-23 1970-05-05 Zerox Corp Photoelectrophoretic imaging method
US3546085A (en) * 1967-01-30 1970-12-08 Xerox Corp Photoelectrophoretic imaging process and suspension

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Weizmann et al., Jour. of Am. Chem. Soc., Vol. 70, (1948), pages 2829-2830 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4105447A (en) * 1975-07-14 1978-08-08 Eastman Kodak Company Photoconductive insulating compositions including polyaryl hydrocarbon photoconductors
US4332948A (en) * 1979-05-25 1982-06-01 Ricoh Company, Ltd. Novel hydrazone compounds and process for preparing the same
US4621156A (en) * 1979-10-29 1986-11-04 Polaroid Corporation Optical filter agents and photographic products and processes containing same
US5041648A (en) * 1989-02-10 1991-08-20 Basf Aktiengesellschaft Phenylhydrazones of β-ionone
US8187359B2 (en) 2006-03-24 2012-05-29 Mesabi Nugget Llc Granulated metallic iron superior in rust resistance and method for producing the same

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