Ricoh Company, Ltd.

Tetsuo Isoda

Mitsuo Aoki

Nobuhiro Nakayama

Yoichiro Watanabe

Masanori Suzuki

Fumihiro Sasaki

Yoshihiro Suguro

Takahisa Kato

Youichirou Watanabe

Karumi Kakigawa

A toner replenishing method for use in a development process of developing latent electrostatic images formed on an electrophotographic photoconductor with a two-component dry developer containing a toner and a carrier, the latent electrostatic images being formed on the electrophotographic photoconductor by uniformly charging the electrophotographic photoconductor to a predetermined potential and exposing the electrically charged photoconductor to light images corresponding to original images, includes the step of replenishing the toner only in a portion of the two-component dry developer as the toner concentration thereof is decreased so as to make up for the used toner in the course of the development of the latent electrostatic images.

Toner replenishing method for use in development process, and

A toner for developing latent electrostatic images including a resin component, with the image fixing temperature of the toner being in the range of 100.degree. to 140.degree. C., and the penetration of the toner, measured when allowed to stand at 60.degree. C. for 4 hours in accordance with Japanese Industrial Standards (JIS) K 2235, being 5 mm or more. The resin component for the toner may include a hydrogenated petroleum resin with a hydrogenation ratio of 50% or more, and optionally polyester resin.

Toner for developing latent electrostatic images

A two-component dry type developer for developing latent electrostatic images comprises (i) toner particles with an average particle diameter of 14 .mu.m or less and (ii) carrier particles with an average particle diameter of 70 .mu.m or less, with the ratio of the average particle diameter of the toner particles to the average particle diameter of the carrier particles being 1/5 or less, with a dynamic resistance of 1.0.times.10.sup.8 .OMEGA. or less, and the specific triboelectric charge quantity generated between the toner particles and the carrier particles per unit weight of the toner particles is 25 .mu.C/g or more.

Two-component dry type developer for developing latent electrostatic

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.

Dry toner for developing latent electrostatic images with improved

The disclosure describes carrier particles for use in a two-component dry-type developer, consisting of core particles which are coated with a silicone resin hardened by an organic tin catalyst.

Carrier particles for use in a two-component dry-type developer

A toner for developing latent electrostatic images is disclosed, which comprises a colorant, and a binder agent comprising (i) polyester resin or epoxy resin, and (ii) styrene - methyl acrylate copolymer.

Carrier particles for use in a two-component dry-type developer for developing latent electrostatic images comprising a core particle and a silicone resin layer coated on the core particle, the silicone resin layer comprising a silicone resin, an organic tin compound and finely-divided electroconductive particles.

Carrier particles for use in a developer for developing latent

Carrier particles for use in a two-component dry-type developer for developing latent electrostatic images are disclosed, which core particle comprises a core particle and a silicone resin layer coated on the core particles, and the silicone resin layer contains an organic tin compound, which serves as a catalyst for hardening the silicone resin layer in the course of the formation of the silicone resin layer on the core particle under application of heat thereto, with a concentration gradient in the direction of the thickness of the silicone resin layer towards the outer surface of the carrier particles.

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Numazu, Japan

Tetsuo Isoda