Abstract: A non-magnetic single-component toner 8 of the present invention has toner mother particles 8a, and external additives 12 comprising: two hydrophobic silicas 13, 14 of which particle diameters are different from each other, i.e. a mean primary particle diameter of 7 nm to 12 nm and a mean primary particle diameter of 40 nm to 50 nm, and a hydrophobic rutile/anatase type titanium oxide 15 having a spindle shape of which major axial diameter is in a range from 0.02 nm to 0.10 nm and the ratio of the major axial diameter to the minor axial diameter is set to be 2 to 8, wherein the external additives 12 adhere to the toner mother particles 8a. By the hydrophobic silicas 13, 14 having work function smaller than the work function of the toner mother particles 8a, the negative charging property is imparted to the toner mother particles 8a and the fluidity is also insured.

Abstract: An image forming apparatus including a latent image carrier and a developing device for charging a toner into a negative polarity by triboelectric charging, wherein the work function of the toner is set to be larger than the work function of the surface of the latent image carrier. When the apparatus includes an intermediate transfer medium, the work function of the toner is set to be larger than the work function of the surface of the intermediate transfer medium. In another embodiment, the work function &PHgr;opc of the surface of the latent image carrier, the work function &PHgr;t of the toner, and the work function &PHgr;TM of the surface of the intermediate transfer medium are set to satisfy a relationship &PHgr;t>&PHgr;OPC>&PHgr;TM. These relationships help to reduce fog, and improve transfer efficiency which reduces the consumption of the toner.

Abstract: The present invention provides a toner containing toner mother particles containing a binder resin and a colorant having added thereinto external additives, e.g., positively electrifiable silica fine particles, negatively electrifiable silica fine particles, titanium oxide fine particles and a long chain fatty acid or a salt thereof, wherein the external additives are added by multistage process, thereby is low in desorption of external additives, has the electrification property for a long period of time, shows high flowability and transfer efficiency, and is not accompanied by the reduction of image density.

Abstract: The invention provides an image-forming apparatus comprising: at least one latent image holding member on which an electrostatic latent image is to be formed; developing devices having toners of different colors for developing the electrostatic latent image on the latent image holding member to form a toner image; and an intermediate transfer medium onto which the thus formed toner image is to be transferred, wherein the intermediate transfer medium has a work function smaller than or equal to the work function of each of the toners.

Abstract: The present invention provides a toner which ensures large mean charging amount and excellent transfer efficiency with no or little amount of reversely charged toner and provides an image forming apparatus using the same. The toner is produced by adding external additives to resin particles containing a coloring agent, wherein the external additives are silica particles and modified silica particles of which outer surfaces are modified with oxide or hydroxide of at least one metal selected from a group consisting of titanium, tin, zirconium, and aluminum, the amount of the modified silica particles being 1.5 times or less of the amount the silica particles. The image forming apparatus uses the toner.

Abstract: A non-magnetic single-component toner 8 of the present invention has toner mother particles 8a, and external additives 12 comprising: two hydrophobic silicas 13, 14 of which particle diameters are different from each other, i.e. a mean primary particle diameter of 7 nm to 12 nm and a mean primary particle diameter of 40 nm to 50 nm, and a hydrophobic rutile/anatase type titanium oxide 15 having a spindle shape of which major axial diameter is in a range from 0.02 nm to 0.10 nm and the ratio of the major axial diameter to the minor axial diameter is set to be 2 to 8, wherein the external additives 12 adhere to the toner mother particles 8a. By the hydrophobic silicas 13, 14 having work function smaller than the work function of the toner mother particles 8a, the negative charging property is imparted to the toner mother particles 8a and the fluidity is also insured.

Abstract: An image forming apparatus of the present invention comprises: a latent image carrier; and a developing means for charging a toner into a negative polarity by triboelectric charging, for converting an electrostatic latent image on said latent image carrier to a visible image with said toner and is characterized in that (1) the work function (&PHgr;t) of said toner is set to be larger than the work function (&PHgr;OPC) of the surface of said latent image carrier, or (2) in case that the apparatus is of a type transferring the visible image to an intermediate transfer medium, the apparatus is characterized in that the work function (&PHgr;t) of said toner is set to be larger than the work function (&PHgr;TM) of the surface of said intermediate transfer medium or (3) the work function (&PHgr;OPC) of the surface of said latent image carrier, the work function (&PHgr;t) of said toner, and the work function (&PHgr;TM) of the surface of said intermediate transfer medium are set to satisfy a relation &PHgr;t>&PHgr

Abstract: Toner is for use in an image forming apparatus of the TonerJet method, which satisfies any one of the following conditions: a) toner in which the content of reverse-polarity large-diameter toner is 10% by count or smaller; b) toner in which the content of reverse-polarity fine-powder toner is 2% by count or smaller; c) toner comprising a silica additive and a titanium oxide additive such that the content x of the titanium oxide additive is in the range of 0<x≦1.5 wt %. For instance, when an image is formed using toner satisfying the condition a) above, that is, toner in which the content of reverse-polarity large-diameter toner is 10% by count or smaller, filming does not occur and an image having an excellent quality is formed (denoted with “◯”). On the other hand, when an image is formed using toner in which reverse-polarity large-diameter toner exceeds 10% by count, filming occurs and the quality of an image deteriorates (denoted with “X”).

Abstract: By causing the movement of charge from a toner to a latent image carrier, the amount of charge of the toner is lowered to an amount of charge suitable for facilitating the transfer of toner so as to improve the transfer efficiency. For this, an image forming apparatus comprises a latent image carrier 1 and a developing means 4 for forming a negatively chargeable toner layer composed of two stories or less on a toner carrier 10 by a toner layer thickness regulating member 9, wherein an electrostatic latent image on the latent image carrier is developed with the toner to form a visible image and the visible image is transferred to a transfer medium 5, and is characterized in that the work function (&PHgr;opc) of the surface of the latent image carrier is set to be larger than the work function (&PHgr;t) of the toner.

Abstract: In an electrophotographic developing method using a magnetic brush consisting of a mixture of magnetic carrier and an electroscopic toner, development is carried out at a toner concentration (Ct. %) in the mixture, which satisfies the requirement represented by the following formula: ##EQU1## wherein Sc stands for the specific surface area (cm.sup.2 /g) of the carrier, St stands for the specific surface area (cm.sup.2 /g) of the toner, and k is a number of from 0.90 to 1.14.A toner image having a high quality can be obtained according to this method.

Abstract: A two-component electrophotographic developer for use in developing a latent electrostatic image of a low potential. The developer is composed of a mixture of a magnetic carrier of spherical sintered ferrite particles having raised and depressed portions attributed to the primary particles on their surface, a median size of from 30 to 50 micrometers, an apparent density of less than 2.6 g/cc and an electric resistance, measured in the form of a magnetic brush, of from 6.times.10.sup.4 to 2.5.times.10.sup.6 ohms and chargeable toner particles having a volume inherent resistivity of at least 1.times.10.sup.13 ohms-cm and a specific inductive capacity of from 4 to 6. In a preferred embodiment, the chargeable toner particles have a median size of from 10 to 14 micrometers and are substantially free from particles having a particle diameter of not more than 5 micrometers. The developer can give an image of a high density, a high resolution and excellent gradation without brush marks.

Abstract: Disclosed is an electrophotographic apparatus comprising a photosensitive drum comprising an amorphous silicon type photoconductor layer formed on an electroconductive substrate, a main charging mechanism for charging the surface of the drum with charges having a predetermined polarity, an imagewise exposure mechanism for forming an electrostatic image corresponding to an image of an original on the surface of the drum, a toner development mechanism for forming a toner image corresponding to the electrostatic image, a toner image transfer mechanism for transferring the toner image formed on the surface of the photosensitive drum to a predetermined paper sheet, a toner cleaning mechanism for removing the residual toner adhering to the surface of the photosensitive drum and a fixing mechanism for fixing the transferred toner image to said paper sheet, wherein a heating mechanism is arranged to heat the surface of the photosensitive drum at a temperature of 30.degree. to 40.degree. C.

Abstract: In a copying machine comprising a photosensitive drum having an amorphous silicon type photoconductive layer, if an image of an original is focussed on the photoconductive layer with a light having a wavelength shorter than 600 nm, the light fatigue of the amorphous silicon photoconductive layer is prevented, and the image memory phenomenon owing to the light fatigue is effectively obviated.

Abstract: A toner for electrophotography, comprising an azoic pigment having a silica core as a coloring component, said azoic pigment comprising a core of a fine powder of silica and a coating of a mono- or polyazoic dye chemically bound to the surface of the silica core through an aminosilane coupling agent.

Abstract: An azoic pigment having a silica core comprising a core of a fine powder of silica having a particle diameter of not more than 10 microns and a coating of a mono- or polyazoic dye chemically bound to the surface of the silica core through an aminosilane coupling agent.

Abstract: An electrically conductive composition is disclosed, which comprises a protonically conductive compound, a finely divided inorganic solid acid and a binder, especially an aqueous emulsion type carboxyl group-containing polymer.This composition has in combination highly improved electric conductivity, low humidity dependency, reduced tacking tendency and high whiteness and can be manufactured at a low cost. This composition is valuable for production of an electro-sensitive recording material.

Abstract: A photosensitive material for electrophotography, which comprises an electroconductive substrate and a photosensitive layer formed on the substrate. The photosensitive layer comprising a charge transfer medium and a charge-generating pigment dispersed in the mediums. The photosensitive layer contains as the matrix resin a thermoplastic polyester consisting essentially of recurring units represented by the following general formula: ##STR1## wherein R.sup.1 stands for a phenylene group or an ethylene group, R.sup.2 stands for a group represented by the formula ##STR2## R.sup.3 stands for a direct bond or a divalent bridging atom or group, and the ring A may have a substituent not participating in the reaction.

Abstract: Disclosed is a photosensitive material for electrophotography containing a pentakisazo pigment of the following formula: ##STR1## wherein the rings A.sub.1 and A.sub.2 may have halogen atoms, alkyl groups or alkoxy groups as substituents at the ortho-positions to the azo groups, the ring B may have a halogen atom, an alkyl group or an alkoxy group as a substituent or may contain the ring Z.sub.1, Z.sub.1 which is an aromatic or hetero ring fused to the benzene ring B, and Y stands for a group of the following formula: ##STR2## in which Z.sub.2 stands for an aromatic ring or a hetero ring, Ar.sub.1 stands for an aromatic ring or a hetero ring, Ar.sub.2 and Ar.sub.3 stand for an aromatic ring, R.sub.0 stands for a hydrogen atom, a lower alkyl group or a phenyl group, R.sub.1 stands for a lower alkyl group, a carboxyl group or an ester thereof, and R.sub.2 and R.sub.3 stand for a hydrogen atom, a lower alkyl group, a phenyl group or a substituted derivative thereof.

Abstract: Disclosed is a one-component type red color magnetic developer having a self-electroscopic property, which comprises particles prepared from a kneaded composition comprising 100 parts by weight of a magnetic powder composed mainly of ocherous gamma-type diiron trioxide, 2.5 to 30 parts by weight of a red azo pigment and 40 to 200 parts by weight of a binder resin, wherein a fixed image of the particles is measured by a color difference meter, the value x is from 0.51 to 0.73, the value y is from 0.22 to 0.40 and the value Y is from 5 to 65%.

Abstract: Disclosed is a heat-sensitive color-forming recording material which comprises a recording layer comprising a particulate phenolic color developer and a particulate leuco pigment, which are dispersed in a binder independently from each other, wherein the phenolic color developer and/or leuco pigment is present in the form of compatible solid particles with a substantially inactive organic solid medium having a melting or softening point lower than that of the phenolic color developer and/or leuco pigment and said organic solid medium is present in said compatible solid particles in an amount .[.2 to 250 times as large as.]. .Iadd.of 0.2 to 250% by weight, based on .Iaddend.the amount of the phenolic color developer and/or leuco pigment on the weight base. This heat-sensitized color-forming recording material is highly sensitive without substantial increase of the fog density.