Abstract: An electrostatic image developing toner containing at least one compound selected from the group consisting of sulfonylurea compounds of the following formula (1): ##STR1## wherein A is a phenyl group which may have a substituent, or a naphthyl group which may have a substituent, and each of B and C which are independent of each other, is a hydrogen atom, an alkyl group, a phenyl group which may have a substituent, or a naphthyl group which may have a substituent, or B and C together form a ring; or the following formula (2):D--SO.sub.2 NHCONH--X--NHCONHSO.sub.2 --E (2)wherein each of D and E which are independent of each other, is an alkyl group, a phenyl group which may have a substituent, or a naphthyl group which may have a substituent, and X is a phenylene group which may have a substituent, a biphenylene group which may have a substituent, or a naphthylene group which may have a substituent.

Abstract: An electroconductive imaging element, that is especially useful in a high speed laser printing process utilizing electrostatography, is comprised of an insulating support, an electrically-conductive layer overlying the support and a thermoplastic dielectric imaging layer overlying the electrically-conductive layer. The electrically-conductive layer, which is comprised of at least 3 milligrams per square meter of a colloidal gel of vanadium pentoxide dispersed in a polymeric binder combines a high degree of transparency with a high degree of electrical conductivity. The thermoplastic dielectric imaging layer has a thickness of at least 0.2 micrometers and a surface resistivity of at least 10.sup.13 ohms/square and is comprised of a thermoplastic polymer with a glass transition temperature of at least 20.degree. C.

Abstract: An electrophotographic dry toner comprising a binder resin and a colorant, having externally added thereto an inorganic compound, preferably spherical silica particles, having been surface treated with at least one treating agent selected from the group consisting of a treating agent selected from a polyethylene, a fatty acid metal salt, and a solid alcohol containing from 20 to 60 carbon atoms. The toner is prepared by treating the inorganic compound with a dispersion or a solution of the treating agent in a solvent and adding the thus surface-treated inorganic compound to a toner. The toner exhibits satisfactory fluidity, satisfactory cleanability, excellent environmental stability, and excellent durability and causes no toner filming phenomenon on a photoreceptor, a carrier used in a two-component developer system, or a charging part used in a one-component developer system.

Abstract: A magnetic toner is constituted by at least a binder resin and a magnetic iron oxide. The magnetic iron oxide is characterized by having an Fe(II) content of 18.5-24.1 wt. %, and shows a BET specific surface area of S (m.sup.2 /g) and an X-ray diffraction pattern giving a half-value width W (deg.) of a diffraction peak corresponding to 311 plane of the magnetic iron oxide in spinel structure, the values S and W satisfying: 4.5.times.10.sup.-3 S+0.130.ltoreq.W.ltoreq.4.5.times.10.sup.-3 S+0.160, and 4.5.ltoreq.S.ltoreq.11.0. Alternatively, the magnetic iron oxide is characterized by having a number-average particle size D satisfying a relationship with W of: -0.08D+0.180.ltoreq.W.ltoreq.-0.08D+0.212, and 0.10.ltoreq.D.ltoreq.0.45. The relationship between W and S or D indicates a good crystallinity of the magnetic iron oxide which provides the magnetic toner with a stable performance for a long period of time. The magnetic iron oxide can be obtained through a heating treatment at a temperature of 130.degree.

Abstract: A non-magnetic one-component developer comprises a binder resin and a colorant, and has a volume-average particle diameter (dv) in a range of 5-15 .mu.m, a ratio (dv/dn) of the volume-average particle diameter (dv) to the number-average particle diameter (dn) in a range of 1.00-1.40, a quotient (Sc/Sr) obtained by dividing the area (Sc) of a circle supposing the absolute maximum length of a particle is a diameter by the real projected area (Sr) of the particle in a range of 1.00-1.30, a product (AxdnxD) of the specific surface area (A) (m.sup.2 /g) as measured in accordance with the BET method, the number-average particle diameter (dn) (.mu.m) and the true specific gravity (D) in a range of 5-10, and a ratio (Q/A) of the charge level (Q) (.mu.c/g) to the specific surface area (A) in a range of 80-150. The developer is substantially spherical from both conditions of Sc/Sr and AxdnxD, and is suitable for use in a development process in which cleaning is conducted at the same time as development.

Abstract: The invention provides low optical density magnetic fluid which is a stable dispersion of fine magnetic particles. The invention further provides a method of forming the stable dispersion which includes providing an ion exchange resin, loading the ion exchange resin with an ion capable of forming a magnetic phase, treating the loaded resin to form magnetic particles and micronizing the resin and magnetic particles in a fluid to form an aqueous stable colloid.

Abstract: The present invention provides a contact-type developing method for developing a static latent image using a single-component non-magnetic toner wherein a non-magnetic toner fusion is hardly occurred. In the contact-type developing method for developing a static latent image using a single-component non-magnetic toner, a single-component non-magnetic toner essentially consisting of a coloring agent and a binder resin of a styrene copolymer having a number average molecular weight of 8,000 to 30,000 and a weight average molecular weight of 100,000 to 300,000, and having a single peak molecular-weight distribution in a gel partition chromatograph is employed.

Abstract: A developer-bearing member with the surface thereof being composed of minute dielectric portions and minute electroconductive portions which are mixedly distributed, the dielectric portions containing an amino coupling agent, is used in an image formation method including the steps of forming numerous micro closed electric fields near the surface of the developer-bearing member by causing the developer-bearing member to selectively hold electric charges on the surface thereof, supplying a non-magnetic one-component type developer containing a toner to the surface of the developer-bearing member to hold the toner on the surface of the developer-bearing member by the micro closed electric fields, and developing a latent electrostatic image formed on a latent-electrostatic-image bearing member to a visible toner image by the toner.

Abstract: Disclosed herein is magnetic particles containing iron as the main component which have an average particle diameter of 0.1 to 3.0 .mu.m and a liquid absorption of not more than 18 m.infin..

Abstract: Disclosed is a one-component magnetic developer for the electrophotography, which comprises one-component magnetic toner particles and at least one fine particulate additive selected from the group consisting of hydrophobic silica, hydrophilic silica and alumina, wherein the one-component magnetic toner particles have a sphericity degree (DS), defined by the following formula, of 70 to 90%, and a specific surface area of 1.4 to 2.0 m.sup.2 /g:DS=Cc/CT (1)wherein Cc represents the outer circumference of a circle having the same area as the projected area of the toner, and CT represent the actual outer circumference of the projected plane of the toner. This developer is excellent in the flowability and can provide an image having a high density.

Abstract: The improved toner is produced by supplying a spheroidizing treatment under mechanical impact force to resin particles that contain at least magnetic particles in a resin and said magnetic particles are substantially spherical in shape.

Abstract: A conductive magnetic toner including a magnetic powder having a specific resistance of not more than 1.times.10.sup.6 .OMEGA..cm in the amount of from 40% by weight to 60% by weight and a carbon black having a specific surface area of 800 m.sup.2 /g to 1500 m.sup.2 /g and an oil absorption of dibutyl phthalate of not less than 200 cc/100 g in the amount of from 8% by weight to 15% by weight is provided.

Abstract: This specification discloses a method of toner transfer development in which a low frequency alternating electrical bias is applied to the space between a latent image bearing member and a developer carrying member to develop the latent image on the latent image bearing member, and an apparatus for carrying out the same method. This bias has a first process in which reciprocal movement of developer particles is effected also between the non-image area of the latent image bearing member and the developer carrying member, and a second process in which the intensity of the bias is adjusted so that one-sided movement of developer particles from the developer carrying member to the image area and one-sided movement of developer particles from the non-image area to the developer carrying member may take place.

Abstract: A toner material comprises toner particles containing at least a coloring matter and a binder, said toner particle having electrically insulating properties and comprising an inside portion having a relatively high relative permittivity and a surface portion having a relatively low relative permittivity.

Abstract: Particulate toner material for use in the development of latent electrostatic images, wherein said particulate toner material is capable of acquiring by triboelectric contact electrification a net negative charge and contains thermoplastic resin(s) as binder in combination with a colorant and a compound capable of imparting a negative charge to the particulate toner material in contact electrification, wherein the latter compound is an anthranilic acid derivative comprising a sulfonamido-group.

Abstract: In a developing device and a dry color toner for color electrophotography. The developing device is provided with a toner conveying member and a toner layer thickness controlling member which is in contact with the toner conveying member. The color toner for developing electrostatic images used in this developing device has the following relation between the number average particle diameter and the volume average particle diameter: ##EQU1## Even after a continuous copying, the developing device and the color toner provide substantially the same image quality as that in the earlier stages of the continuous copying.

Abstract: New electrostatographic toners and developers are provided containing novel charge control agents comprising amide-containing quaternary ammonium salts having the structure: ##STR1## wherein R.sub.1 is C.sub.1 -C.sub.6 alkyl or aryl, R.sub.2 and R.sub.3, which can be the same or different, are alkyl or aryl, R.sub.4 is alkyl, aryl or aralkyl, R.sub.5 is hydrogen or alkyl, X is --CH.sub.2).sub.n, Z.sup..crclbar. is an anion and n is an integer from 2 to 6.Such amide-containing quaternary ammonium salts also cause toner particles containing them to display lower fusing temperatures and improved paper adhesion indexes.

Abstract: A method for developing electrostatic latent image on the surface of a photosensitive drum using one-component developer. The developer has an average particle diameter of 7-15 .mu.m. Particles of up to 5 .mu.m diameter constitutes at most 25% in the particle number distribution. Particles of no less than 20 .mu.m diameter constitute at most 5% in the particle size volume distribution. The developer particles can be sufficiently triboelectrically charged so as to prevent fogging of developed images and to obtain developer images of good quality.

Abstract: An image forming apparatus is constituted by an image-bearing member for bearing a latent image, and a developing apparatus for developing the latent image. The developing apparatus is constituted by a developer container for containing a toner, and a developer-carrying member for carrying and conveying the toner contained in the developer container to a developing zone opposite the image-bearing member. The developer-carrying member is provided with a coating layer containing electroconductive fine particles. A developer suitable for use in the above developing apparatus is given by a toner, which comprises a binder resin composition which contains 10-70 wt. % of a THF (tetrahydrofuran)-insoluble content and the remainder of a THF-soluble content including a component with a molecular weight of 10000 or below on a GPC (gel permeation chromatography) chromatogram of the THF-soluble content constituting 10-50 wt. % of the binder resin.

Abstract: A colored magnetic encapsulated toner composition comprised of a core comprised of a polymer binder, magnetic metal particles, whitener, color pigment, dye or mixtures thereof, and which core is encapsulated in a polymeric shell, and wherein the toner surface comprises an optional conductive metal oxide, or metal oxides and an optional release additive, or additives.

Abstract: A magnetic developer for developing an electrostatic latent image, including hydrophobic silica fine powder and an insulating magnetic toner comprising at least a binder resin and a magnetic material comprising spherical magnetic particles; wherein 0.16 to 1.6 wt. parts of the hydrophobic silica fine powder is mixed with 100 wt. parts of the insulating magnetic toner; the developer contains 17-60% by number of magnetic toner particles having a particles size of 5 microns of smaller, 5-50% by number of magnetic toner particles having a particle size of 6.35-10.08 microns, and 2.0% by volume or less of magnetic toner particles having a particle size of 12.7 microns or larger.

Abstract: Disclosed herein are magnetic particles used for an electrostatic latent image developer comprising composite particles containing from more than 80% by weight to not more than 99% by weight of fine ferromagnetic particles and a cured phenol resin, and having a number-average particle diameter of from not less than 1 .mu.m to less than 10 .mu.m and an apparent density of not greater than 1.5 g/cm.sup.3.

Abstract: An ionographic imaging member containing a conductive layer and a uniform and continuous dielectric imaging layer free of voids, the imaging layer having a dielectric constant of from about 1.5 to about 40 and a thickness of at least about 45 micrometers, the thickness divided by the dielectric constant having a value of from about 30 to about 60 micrometers. This member may be used in an ionographic imaging process.

Abstract: A developing system for an electrostatic image reproduction machine comprising a mono-component developer having toner particles of selected diameters dispersed therein; container for holding the developer; a developer sleeve for receiving a quantity of the developer from the container; a restriction member for forming a thin layer of the developer on the sleeve; a device for impacting an electric charge to the developer layer; and a latent image retainer for selectively receiving the electrically charged layer for forming a visible image. The developer satisfies the expression d.sub.75 /d.sub.25 .ltoreq.d.sub.50 /40+1.2 where d.sub.25, d.sub.50 and d.sub.75 represent diameters of toner particles when the percentage by volume or by weight of toner particles of that diameter as compared to the total volume or weight of the developer is 25%, 50% and 75%, respectively. A developer and method for making the developer are also described.

Abstract: A monocomponent developing device for use in the electrophotographic image forming apparatus, which comprises a developing roller rotatably supported so as to confront a rotatably supported photoreceptor, a toner supply means for supplying toner onto the developing roller, a regulating member held in contact with a surface of the developing roller and operable to triboelectrically charge the toner, supplied onto the surface of the photoreceptor, while regulating the amount of the toner, and a coating film formed on at least a portion of a surface of the regulating member which is held in contact with the developing roller. The coating film has the same polarity in triboelectric series as that of the toner and is abradable after repetition of developing with a surface of the regulating member consequently exposed.

Abstract: An image forming method which includes the steps of providing a developing agent holder for holding one component developing agent layer arranged to contact a latent image holder, developing a latent image on the latent image holder and to simultaneously clean up the developing agent adhering to the surface a non-latent image area on the latent image holder, wherein the cleaning up is carried out under the condition expressed by the following formula:0.5.ltoreq.(Vd/Vp).multidot.m.ltoreq.3.0wherein ghe moving speed of the developing agent holder is defined as Vd, the moving speed of the surface of the latent image holder is defined as Vp and the developing agent adhering density is defined as m (mg/cm.sup.2), and the amount of the remaining toner after transferring that remains on the latent image phase of the latent image holder is set less than 0.35 mg/cm.sup.2.

Abstract: A developer for developing electrostatic images, comprising: at least, 100 wt. parts of a negatively chargeable magnetic toner having a volume-average particle size of 5 to 30 microns; 0.1 to 3 wt. parts of potitively chargeable resin particles having an average particle size of 0.1 to 1.0 micron; and 0.05 to 3 wt. parts of hydrophobic silica fine powder having a triboelectric chargeability of -100 to -300 .mu.c/g.

Abstract: This specification discloses a method of toner transfer development in which a low frequency alternating electrical bias is applied to the space between a latent image bearing member and a developer carrying member to develop the latent image on the latent image bearing member, and an apparatus for carrying out the same method. This bias has a first process in which reciprocal movement of developer particles is effected also between the non-image area of the latent image bearing member and the developer carrying member, and a second process in which the intensity of the bias is adjusted so that one-sided movement of developer particles from the developer carrying member to the image ara and one-sided movement of developer particles from the non-image area to the developer carrying member may take place.

Abstract: A toner for developing electrostatic images is disclosed which comprises a coloring agent, a styrene homopolymer or copolymer with a vinyl monomer or moners, and polypropylene in an amount between about 0.02 and 40 parts by weight per 100 parts by weight of the styrene homopolymer or copolymer.

Abstract: According to the present invention, the incorporation of polymeric-magnetic coordination complex powder in a toner effects improvements of chargeability, dusting resistance and fixing properties, and the formation of clear color images.

Abstract: An image forming method, comprising the steps of: providing an electrophotographic photosensitive member comprising an organic photoconductor, and a toner-carrying member carrying thereon a magnetic toner disposed opposite to the photosensitive member with a predetermined clearance in a developing region; the photosensitive member comprising at least two species of charge-generating substances and carrying thereon a digital and an analog electrostatic images; carrying the magnetic toner on the toner-carrying member to the developing region while regulating the magnetic toner so as to provide a thickness smaller than the clearance, the magnetic toner having a specific particle size distribution and a volume-average particle size of 4-10 microns; and developing the electrostatic images with the magnetic toner.

Abstract: A toner for developing electrostatic images is disclosed which comprises a coloring agent, a styrene homopolymer or copolymer with a vinyl monomer or moners, and polypropylene in an amount between about 0.02 and 40 parts by weight per 100 parts by weight of the styrene homopolymer or copolymer.

Abstract: Particulate toner material for use in the development of latent electrostatic images, wherein said particulate toner material is capable of acquiring by triboelectric contact electrification a net positive charge and contains thermoplastic resin(s) as binder in combination with a colorant and a colorless compound capable of imparting a positive charge to the particulate toner material in contact electrification, wherein said colorless compound contains at least one piperidine nucleus substituted with an --NH-acyl group, N-substituted ureido or N-substituted thioureido group.

Abstract: A toner for developing electrostatic images is disclosed which comprises a coloring agent, a styrene homopolymer or copolymer with a vinyl monomer or moners, and polypropylene in an amount between about 0.02 and 40 parts by weight per 100 parts by weight of the styrene homopolymer or copolymer.

Abstract: A developer for developing electrostatic images, comprising a non-magnetic toner, the toner containing 17-60% by number of non-magnetic toner particles of 5 microns or smaller, containing 1-30% by number of non-magnetic toner particles of 8-12.7 microns, and containing 2.0% by volume or less of nonmagnetic toner particles of 16 microns or larger; wherein the non-magnetic toner has a volume-average particle size of 4-10 microns, and the non-magnetic toner particles of 5 microns or smaller have a particle size distribution satisfying the following formula:N/V=-0.04N+k,wherein N denotes % by number of non-magnetic toner particles of 5 microns of smaller, V denotes % by volume of non-magnetic toner particles of 5 microns or smaller k denotes a positive number of 4.5-6.5, and N denotes a positive number of 17-60.

Abstract: A dry toner composition comprising (A) a binder resin, (B) a colorant and (C) charge control agents comprising a special metal complex of oxycarboxylic acid (C-1) and a special metal complex of azo compound (C-2) can provide high quality images without causing toner flying even after printed for a long period of time, and thus is useful for providing a dry developer and a process for forming images using said dry developer.

Abstract: A positively chargeable, one component type magnetic developer, comprises:100 parts by weight of a positively chargeable magnetic toner having triboelectric charges of +9 .mu.c/g to +20 .mu.c/g and a volume average particle size of 5 to 30 .mu.m,0.01 to 5 parts by weight of negatively chargeable resin fine particles having triboelectric charges of -10 .mu.c/g to -40 .mu.c/g and a primary average particle size of 0.01 to 4 .mu.m, and0.05 to 10 parts by weight of positively chargeable silica fine particles having triboelectric charges of +100 to +300 .mu.c/g and a primary average particle size of 5 m.mu. to 30 m.mu..

Abstract: Disclosured is a toner comprising colored particles and a magnetic shell coated thereon, wherein said colored particles are composed of a binder resin and a coloring agent, and said magnetic shell is formed from an iron-oxide type magnetic material. The toner can be fixable at a low temperature or a low pressure, but the toner particles do not agglomerate with each other during long-term storage.

Abstract: An insulative magnetic toner disclosed herein comprises a magnetic powder, a negative charge control agent, a binder resin and a compound having phenazine ring amorphous-silicon photoreceptor.The magnetic toner according to the invention is effective for preventing the occurrence of picture image blurring under high humidity when used in an amorphous-silicon photoreceptor.

Abstract: A developer for developing electrostatic images, comprising a magnetic toner comprising a binder resin and magnetic powder, the developer containing 17-60% by number of magnetic toner particles of 5 microns or smaller, containing 1-23% by number of magnetic toner particles of 8-12.7 microns, and containing 2.0% by volume or less of magnetic toner particles of 16 microns or larger; wherein the magnetic toner has a volume-average particle size of 4-9 microns, and the magnetic toner particles of 5 microns or smaller have a particle size distribution satisfying the following formula:N/V=-0.04N+k,wherein N denotes % by number of magnetic toner particles of 5 micron or smaller, V denotes % by volume of magnetic toner particles of 5 microns or smaller, k denotes a positive number of 4.5-6.5, and N denotes a positive number of 17-60.

Abstract: A toner for developing latent electrostatic images is disclosed, which comprises a binder resin comprising a component selected from the group consisting of: (1) a mixture of the ternary copolymers of styrene, methyl acrylate, and ethyl acrylate, (2) a mixture of the binary copolymers of two monomers from among the monomers of styrene, methyl acrylate, and ethyl acrylate and homopolymers containing the remaining monomer or the copolymers of that monomer and the other monomers, and (3) a mixture of the respective homopolymers.

Abstract: There is described a novel toner for developing static latent image, of which relaxation time is adjusted to 5 through 20 milliseconds at 100 KHz of frequency. The toner is perfectly compatible with cleaning requirements, and thus, fusion or filming of toner onto the surface of photoreceptor is secured prevented, so that clear and distinct image can be securely produced for a long time.

Abstract: A magnetic toner comprising a binder resin, magnetic powder and 0.1-10 wt. % (based on resin component) of a low-molecular weight polyalkylene, the binder resin comprising a vinyl-type polymer having 5 to 80 wt. % of a tetrahydrofuran (THF)-insoluble; the magnetic toner having a melt index of 0.2 to 12 g/10 min. (125.degree. C., 10 kg load); the residual magnetization .sigma..sub.r and the volume-average particle size d of the magnetic toner satisfying the following formula:3.7-0.11d.ltoreq..sigma..sub.r .ltoreq.6.5-0.23d,wherein .sigma..sub.r represents a residual magnetization (emu/g) under an external magnetic field of 1 KOe and d represents a volume-average particle size of 3 to 16 microns.

Abstract: Disclosed is an electrophotographic magnetic toner comprising 40-80% binder resin, a waxy material such as a low molecular weight polypropylene or polyethylene, a charge control agent and 20-60% iron oxide having a number average particle size of 0.2-0.7 microns and wherein trivalent Fe is present in excess and wherein the iron oxide contains 16-25% FeO and about 75-84% Fe.sub.2 O.sub.3.

Abstract: A method for developing electrostatic latent images on the surface of a photosensitive drum uses a one-component developer. The developer has an amount of triboelectric charge within the range of about 30-100 .mu.m c/m.sup.2, and a true specific gravity of at least about 1.2. The developer can be sufficiently moved to the electrostatic latent image so as to prevent fogging of developed images and to consistently obtain developed images of good quality.

Abstract: A magnetic toner for developing electrostatic images, comprising at least a binder resin and a magnetic powder; the binder resin having 10 to 70 wt. % of a THF (tetrahydrofuran)-insoluble and a THF-soluble, the THF-soluble providing a molecular weight distribution in the chromatogram of GPC (gel permeation chromatography) thereof such that it provides a rate (Mw/Mn) of weight-average molecular weight (Mw)/number-average molecular weight (Mn).gtoreq.5, there are a peak in the molecular weight range of 2,000 to 10,000 and a peak or shoulder in the molecular weight range of 15,000 to 100,000 and a component having a molecular weight of 10,000 or smaller is contained in an amount of 10-50 wt. % based on the binder resin; the magnetic powder comprising spherical magnetic particles having a bulk density of 0.6 g/ml or larger.

Abstract: A magnetic toner suitably used for developing a digital latent image is provided. The magnetic toner comprises a binder resin and a specific magnetic material comprising spherical magnetic particles which have a tap density of 1.2-2.5 g/cm.sup.3 and a linseed oil absorption of 5-30 ml/100 g. On the basis of the characteristics of the above-mentioned magnetic material, the magnetic toner has good image forming characteristics including image density, reproducibility of thin lines and resolution.

Abstract: A process of imaging which comprises (1) generating an image; (2) developing the image formed with a single component pressure fixable toner composition with a resistivity of from about 10.sup.4 to about 10.sup.7 ohm-cm, and comprised of resin particles, magnetite, and a release fluid therein, which toner contains conductive particles on the surface thereof; (3) transferring the developed image to a suitable substrate; and (4) fixing the image thereto by pressure exerting a force of from about 200 to about 400 pounds per linear inch.

Abstract: A reverse development method comprising the steps of forming electrostatic image on the surface of an image-bearing member; supplying a developer comprising chargeable magnetic toner based on magnetic powder and a resin development roll comprising a conductive core, a permanent magnet arranged around the conductive core and a dielectric layer provided around and fixed to the permanent magnet and having conductive particles mutually insulated from each other; conveying the developer onto a surface of the image-bearing member by rotation of the developement roll so that the magnetic toner is attracted to the uncharged portions of the image; characterized in that the chargeable magnetic toner contains an aliphatic acid metal salt and is coated with hydrophobic silica.

Abstract: A negatively charged toner composition comprised of resin particles, pigment particles, and as a charge enhancing additive certain salts of 5,5'-spirobi(5H-dibenzoborole).