Abstract: An anthraquinone dye and a liquid crystal composition containing the dye are disclosed.The liquid crystal composition is preferably used in an electro-optic cell which enables a good color display utilizing the guest-host effect of the liquid crystal.

Abstract: This invention relates to a guest-host type liquid crystal composition and a color liquid crystal display device in which said composition has been sealed. This invention provides a liquid crystal composition containing a specific anthraquinone dye as a pleochroic dye which, as the guest dye, has a degree of orderness of the alignment (order parameter) in the host liquid crystal in the range from 0.5 to 1, shows remarkable contrast between the colored state and the uncolored state, and is excellent in stability to light, heat, and the like. Further, this invention provides a color guest-host type liquid crystal display device in which said liquid crystal composition has been sealed.

Abstract: Pleochroic azo dyes represented by the formula (I): ##STR1## wherein X represents group --OCOR.sup.1 or --COOR.sup.1 (wherein R.sup.1 represents an alkyl group, an alkoxyalkyl group, an alkoxyphenyl group, an alkylcyclohexyl group, an alkoxyalkylcyclohexyl group, a cycloalkylcyclohexyl group, an alkoxycyclohexyl group, or a phenyl group substituted by a substituent selected from among an alkyl group containing 3 to 18 carbon atoms, an alkoxyalkyl group, a cycloalkyl group, an aryl group, a cyano group, a halogen atom, an acyloxy group, a carboxylic acid ester group, and an arylazo group); Y represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, a cycloalkyl group, an alkoxy group, a nitro group, a cyano group, a carboxylic acid ester group, an acyloxy group, an alkylsulfonyl group, an aryl group, a halogen atom, or group ##STR2## wherein R.sup.2 and R.sup.3 each represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, or R.sup.2 and R.sup.

Abstract: The present liquid crystal composition is characterized by containing a dye of anthraquinone series represented by the following general formula (1) dissolved as a guest in a host liquid crystal: ##STR1## wherein R represents an alkyl group or a cycloalkyl group. The alkyl group or the cycloalkyl group of the dye of anthraquinone series includes those substituted by alkyl, hydroxyl, alkoxy, cycloalkyl, aryl, aryloxy, dialkylamino, or heterocyclic residue. Furthermore, the liquid crystal composition can contain two or more other kinds of the dye of anthraquinone series, or can be used in combination with other dyes. In the dye of anthraquinone series, the group --COOR at the 2-position and the group --CN at the 3-position are particularly important for realization of cyan color and a high S value.The dye of anthraquinone series is particularly effective for preparation of a black dye.

Abstract: Phthalonitrile derivatives represented by the formula (I): ##STR1## (wherein X and Y each represents an alkyl group having 1 to 9 carbon atoms, an alkoxy group havng 1 to 9 carbon atoms, ##STR2## (wherein R.sup.1 represents a hydrogen atom, --C.sub.m H.sub.2m+1, --O--(CH.sub.2 CH.sub.2 O).sub.n --C.sub.m H.sub.2m+1, ##STR3## or a halogen atom, wherein m represents an integer of 1 to 9 and n represents 0, 1 or 2), but at least one of X and Y does not represent a methyl group, and Y does not not represent an alkyl group having 1 to 9 carbon atoms or an alkoxy group having 1 to 9 carbon atoms in the case that X represents R.sup.1 H and R.sup.1 represents an alkyl group having 1 to 9 carbon atoms).

Abstract: A liquid crystal composition comprising a host liquid crystal and at least one perylene dye dissolved therein represented by the formula: ##STR1## wherein X represents an oxygen atom or a sulfur atom, R.sup.1 and R.sup.2 each represents an aryl group when X represents an oxygen atom; or an aryl group or an alkyl group containing 1 to 18 carbon atoms when X represents a sulfur atom.

Abstract: A liquid crystal composition comprising a host liquid crystal And a pleochroic dye dissolved therein as a guest material is described, which is characterized in that the pleochroic dye contains an anthraquinone-based dye yielding a Magenta color and/or an orange color.

Abstract: Electrophotographic copying is carried out by electrostatically forming a latent image on a recording medium, supplying a magnetic toner of single component system containing at least a resin and fine particles of forromagnetic material on a non-magnetic sleeve provided with a permanent magnet roller having a plurality of magnetic poles therein, transporting the magnetic toner into a gap between the recording medium and the non-magnetic sleeve, attaching the magnetic toner to the recording medium, thereby developing the latent image into a visible image, electrostatically transferring the toner image thus formed on the recording medium onto a transfer sheet, and fixing the transferred image, thereby obtaining a final image, wherein the magnetic toner has a resistivity of more than 5.times.10.sup.15 .OMEGA.cm and a relative dielectric constant of less than 3.0.

Abstract: A liquid crystal composition contains a pleochroic dye which is an anthraquinone dye having the group --OCOO-- in a substituent group. Such a dye shows a reasonable order parameter and good solubility as well as stability in the liquid crystal composition.

Abstract: A color liquid crystal display device wherein a nematic liquid crystal to which a dichroic dye and an optically active substance have been added is used as the liquid crystal layer and the amount of said optically active substance added is so selected as to fall in a range making steep the threshold voltage characteristics of the liquid crystal.

Abstract: A pleochroic color display device is provided which comprises a layer of guest-host type liquid crystal sandwiched between two transparent electrodes for driving the liquid crystal, the guest-host liquid crystal containing a dichroic dye as guest material, and a color filter disposed in front or rear of the layer of the guest-host type liquid crystal. High contrast pleochroic color displays can be obtained by selecting a blackish dye as the dichroic dye. Dichroic displays other than white ones can be produced by the use of a single liquid crystal cell and a single color filter (with one color).

Abstract: An electrostatic photographic method for reversal development using a magnetic brush, with the magnetic brush and photoconductive drum being grounded, and with the development being performed using a dry reversal developer comprising 100 parts by weight of a carrier having ferromagnetic properties and 1 to 10 parts by weight of a toner having a volume specific resistance falling within the range between 3.5.times.10.sup.9 and 1.times.10.sup.11 .OMEGA.-cm.

Abstract: A liquid crystal composition containing at least one quinophthalone series dye represented by the formula ##STR1## wherein: X represents hydrogen, a chlorine atom or a bromine atom; and R represents --OR.sup.1 or --SR.sup.1, wherein R.sup.1 represents an alkyl group, a cycloalkyl group, an alkoxyalkyl group, a phenyl group, a p-hydroxyphenyl group, a p-cycloalkylphenyl group, a p-alkylphenyl group, a p-alkoxyphenyl group or an aralkyl group; ##STR2## wherein R.sup.2 and R.sup.3 each represents hydrogen, an alkyl group, a hydroxyalkyl group, an alkoxyalkyl group, a cycloalkyl group, a phenyl group, a p-alkylphenyl group, a p-hydroxyphenyl group, a p-alkoxyphenyl group or an aralkyl group; or a saturated heterocyclic ring.

Abstract: A guest-host liquid crystal display device is disclosed which undergoes a focalconic-homeotropic phase transition. The device has a guest-host material layer including (a) a nematic liquid crystal having a positive dielectric anisotropy, (b) an optically active material for putting the nematic liquid crystal in a cholesteric condition, and (c) a pleochroic dye, and has an electrode means for establishing an electric field in the material layer in order that the material layer undergoes the phase transition from the cholesteric condition to the homeotropic condition. Liquid crystal molecules in contact with the surface of the electrode are oriented with their longitudinal axes perpendicular to the electrode surface, with an orientation treatment carried out in the electrode surface or by an orientation film provided on the electrode surface. Thus, the material layer assumes the focalconic condition in the absence of the electric field. A chiralnematic compound is employed as the optically active material.

Abstract: Magnetic toner employable as a developer for electrophotographic duplication system consisting of the steps of developing electrostatic latent image on a carrier, overlaying a copying sheet on said carrier of developed image, and transferring the developed image to said sheet, characterized by containing magnetic fine particles of a electric resistivity from 10.sup.9 .about.10.sup.16 .OMEGA..multidot.cm (at 4000 V/cm DC) and dielectric constant from 2.6.about.5.

Abstract: A one-component magnetic developer powder for developing an electrostatic latent image formed according to an electrophotographic process comprising non-agglomerative essentially spherical members consisting essentially of plastics binder, magnetic particles and first electric conductive particles dispersed therein, and second electric conductive particles embedded on a spherical surface of the member, the resistivity of the surface layer of the powder being less than that of the inner portion.The developer powder according to the present invention has a good electrical uniformity and the flowability of the developer powder is very good. Productivity of the same is also very good.

Abstract: A liquid developer for electro photography which comprises a coloring agent, a coating agent, a resistivity controlling agent and a carrier liquid which disperses or dissolves the said three agents is suitable for providing high reproducibility of images when at least one of the following copolymers are used as said coating agent:(a) Copolymer of an acrylic acid compound represented by the following general formula (i) and a para-alkylstyrene represented by the following general formula (ii): ##STR1## (WHEREIN R.sub.1 is hydrogen or an alkyl group of 1-6 carbon atoms and R.sub.2 is hydrogen or C.sub.m H.sub.p X.sub.q wherein m=1-6 and p+q=2m+1 or p+q=m-1 and X is a halogen, amino group, secondary or tertiary amino group having an alkyl group of 1-4 carbon atoms, nitro group, cyano group or hydroxyl group) ##STR2## (WHEREIN R.sub.3 is an alkyl group of 2-18 carbon atoms).

Abstract: Organic photoconductive materials comprising as an active ingredient a photoconductive copolymer consisting of 3 to 50 mole % of at least one acrylic monomer represented by the formula ##STR1## wherein R.sub.1 is hydrogen or methyl; and R.sub.2 is a group of the formula --C.sub.n H.sub.2n+1 or a group of the formula --CH.sub.2).sub.m X [wherein n is an integer of 0 to 18; m is an integer of 1 to 4; and X is a group of the formula --OR.sub.3 or ##STR2## (wherein R.sub.3 is a group of the formula --C.sub.l H.sub.2l+1 ; and l is an integer of 0 to 4)], and 97 to 50 mole % of a photoconductive monomer having an .alpha.,.beta.-unsaturated bond.

Abstract: Homopolymers or copolymers of 9-(p-vinylphenyl)-acridine show excellent photoconductivity.