G03G5/14704

IMAGE FORMING APPARATUS AND IMAGE FORMING METHOD

An image forming apparatus is provided that includes: an image bearer; a charger; an irradiator; a developing device containing a toner; and a transfer device. The image bearer has a Martens hardness of from 185 to 250 N/m.sup.2. The toner satisfies a relation 0.13X/Dn0.16, where X [m] represents an average value of an amount of deformation of the toner by micro-indentation at when a load reaches 3.0010.sup.4 N at a loading rate of 3.010.sup.5 N/sec under an environment of 32 degrees C. and 40% RH, and Dn [m] represents a number average particle diameter of the toner. The toner contains an external additive comprising silica particles and particles composed mainly of strontium titanate. The particles composed mainly of strontium titanate further contain a third element M selected from the group consisting of La, Mg, Ca, Sn, and Si.

ELECTROPHOTOGRAPHIC PHOTORECEPTOR AND IMAGE FORMING APPARATUS
20200257211 · 2020-08-13 · ·

An electrophotographic photoreceptor includes a cylindrical substrate; and a surface layer located on an outer surface of the cylindrical substrate. At least a substrate central portion in a cylindrical axial direction of the outer surface of the cylindrical substrate is formed as a rough surface, and a surface roughness of a surface-layer central portion in the cylindrical axial direction of an outer surface of the surface layer is larger than that of at least one of two surface-layer end portions in the cylindrical axial direction of the outer surface of the surface layer. An image forming apparatus includes the electrophotographic photoreceptor; and a peripheral member capable of contacting a surface of the electrophotographic photoreceptor.

ELECTROPHOTOGRAPHIC IMAGE FORMING METHOD
20200257213 · 2020-08-13 ·

Provide is an electrophotographic image forming method containing: a charging step, an exposure step, a developing step, a transfer step and a cleaning step by using a photoreceptor, wherein the charging step has a charging device for charging the surface of the photoreceptor; the photoreceptor has a protective layer, the protective layer contains a polymerized cured product of a composition containing a polymerizable monomer and an inorganic filler, a surface of the protective layer has a plurality of convex portions due to protrusion of the inorganic filler; in the developing step, a toner in which alumina particles are externally added to toner mother particles is used, and an average distance R between adjacent convex portions among the plurality of convex portions is set in the range of 100 to 250 nm.

ELECTROPHOTOGRAPHIC PHOTOSENSITIVE MEMBER, PROCESS CARTRIDGE, AND ELECTROPHOTOGRAPHIC APPARATUS
20200241434 · 2020-07-30 ·

The electrophotographic photosensitive member includes: a support; a charge-generating layer; and a charge-transporting layer, the charge-generating layer and the charge-transporting layer being arranged on the support, wherein a surface layer of the electrophotographic photosensitive member contains: inorganic particles having an average particle diameter (L) of primary particles of 5 nm or more and 50 nm or less; and resin particles having an average particle diameter (L) of primary particles of 0.1 m or more and 5.0 m or less, and wherein in any cross-section of the surface layer, (Sm)/(S)0.3 is satisfied, where a region within (L/2) from a surface of each of the resin particles is defined as a region (M), a sum of cross-sectional areas of the inorganic particles in the any cross-section is represented by (S), and a sum of cross-sectional areas of the inorganic particles that are included in the region (M) is represented by (Sm).

ELECTROPHOTOGRAPHIC PHOTOSENSITIVE MEMBER, PROCESS CARTRIDGE, AND ELECTROPHOTOGRAPHIC APPARATUS
20200218171 · 2020-07-09 ·

Provided is an electrophotographic photosensitive member including a surface layer containing: a copolymerization product of a composition containing a hole-transportable compound having a chain-polymerizable functional group and a compound having a specific structure; and metal oxide particles.

Organic photoconductor drum having an overcoat containing nano metal oxide particles and method to make the same

An improved organic photoconductor drum having a protective overcoat layer and method to make the same is provided. The protective overcoat layer is prepared from a curable composition including nano metal oxide particles sized less than 400 nm in combination with an urethane acrylate resin having at least 6 functional groups.

Organic photoconductor drum having an overcoat containing nano metal oxide particles and method to make the same

An improved organic photoconductor drum having a protective overcoat layer and method to make the same is provided. The protective overcoat layer is prepared from a curable composition including nano metal oxide particles sized less than 400 nm in combination with an urethane acrylate resin having at least 6 functional groups.

Electrophotographic photoreceptor, and electrophotographic image forming method and electrophotographic image forming apparatus using the same

An electrophotographic photoreceptor includes an outermost layer formed of a polymerized cured product of a composition containing a polymerizable monomer and metal oxide particles surface-treated with a surface treatment agent having a silicone chain, wherein a ratio (r/r) between a number average primary particle diameter (r) of metal oxide particles which are untreated base particles of the metal oxide particles surface-treated with the surface treatment agent having a silicone chain and a sphere equivalent particle diameter (r) of the untreated base particles calculated from a specific surface area measured by a nitrogen adsorption method is 1.5 or more and 6.0 or less, and a surface treatment amount with the surface treatment agent having a silicone chain per surface area of the untreated base particles is 0.0005 g/m.sup.2 or more and 0.0015 g/m.sup.2 or less.

ELECTROPHOTOGRAPHIC IMAGE FORMING APPARATUS AND ELECTROPHOTOGRAPHIC IMAGE FORMING METHOD
20200142344 · 2020-05-07 ·

An electrophotographic image forming apparatus includes: an electrophotographic photoreceptor; a charger that charges a surface of the electrophotographic photoreceptor; an exposer that exposes the charged electrophotographic photoreceptor; a developer that supplies a toner to the electrophotographic photoreceptor on which an electrostatic latent image is formed; a transferer that transfers a toner image formed on the electrophotographic photoreceptor; and a cleaner that removes a residual toner remaining on a surface of the electrophotographic photoreceptor, wherein the electrophotographic photoreceptor includes an outermost layer, a surface of the outermost layer has a projection structure due to a ridge of the inorganic filler, the toner contains toner base particles and metal oxide particles as an external additive externally added to the toner base particles, 70% or more of the toner base particles are covered with the metal oxide particles as the external additive, and following formulas (1) to (3) are satisfied.

[00001] [ Numerical .Math. .Math. formula .Math. .Math. 1 ] R 2 2 .Math. 2 .Math. R 1 .Math. R 3 - R 1 2 ( 1 ) 0 < R 1 < R 3 ( 2 ) 0 < R 2 250 ( 3 )

Photosensitive body including protective layer formed on photosensitive layer

A photosensitive body is provided. The photosensitive body includes a photosensitive layer, and a protective layer formed on the photosensitive layer, and the protective layer includes a urethane oligomer acrylate and a modified perfluoropolyether acrylate.