Canon Kabushiki Kaisha

Minekazu Endo

Satoshi Matsunaga

Hirohide Tanikawa

Tadashi Doujo

Nene Shibayama

Yuichi Mizoh

Yoshihiro Ogawa

Toshiaki Nakahara

Koichi Tomiyama

Keita Nozawa

A toner having a negative triboelectric chargeability is constituted by at least a binder resin, a colorant and an organic metal compound. The toner is characterized by: (a) the organic metal compound is an organic zirconium compound comprising a coordination or/and a bonding of zirconium and an aromatic compound as a ligand or/and an acid source selected from the group consisting of aromatic diols, aromatic hydroxycarboxylic acids, aromatic monocarboxylic acids, and aromatic polycarboxylic acids, (b) the binder resin is a resin selected from the group consisting of (i) a polyester resin and (ii) a hybrid resin component comprising a polyester unit and a vinyl polymer unit, (c) the binder resin has an acid value of 2-50 mgKOH/g, and (d) the toner contains a TFT (tetrahydrofuran)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting a main peak in a molecular weight range of 3,000-20,000 and including 3-25% of a component having molecular weights of at least 5&times;10,.

Toner having negative triboelectric chargeability and image forming method

A toner having a negative triboelectric chargeability is constituted by at least a binder resin, a colorant, a wax and an organic metal compound. The toner is characterized in that: (a) the toner has an acid value of 5-35 mgKOH/g, (b) the binder resin comprises a vinyl polymer, (c) the binder resin in the toner contains a chloroform-insoluble content in an amount of 3-50 wt. %, (d) the toner contains a THF (tetrahydrofuran)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting a main peak in a molecular weight range of 5,000-30,000 and at least one sub-peak and/or shoulder in a molecular weight range of 2.times.10.sup.5 -15.times.10.sup.5 and including 15-70% of a component having molecular weights of 1.times.10.sup.4 -10.times.10.sup.4, and (e) the organic metal compound is an organic zirconium compound comprising a coordination or/and a bonding of zirconium and an aromatic compound as a ligand or/and an acid source selected from the group consisting of aromatic diols, aromatic hydroxycarboxylic acids, aromatic monocarboxylic acids, and aromatic polycarboxylic acids.

Toner having negative triboelectric chargeability and image forming

An electrophotographic toner is composed of at least a binder resin, a colorant, and a wax. The binder resin (a) comprises a polyester resin, a vinyl resin and a hybrid resin component comprising a polyester unit and a vinyl polymer unit, (b) has a THF (tetrahydrofuran)-soluble content (W1) of 50-85 wt. % and a THF-insoluble content (W2) of 5-50 wt. %, an ethyl acetate-soluble content (W3) of 40-98 wt. % and an ethyl acetate-insoluble content (W4) of 2-60 wt. %, a chloroform-soluble content (W5) of 55-90 wt. % and a chloroform-insoluble content (W6) of 10-45 wt. %, respectively after 10 hours of Soxhlet extraction with respective solvents, giving a ratio W4/S6 of 1.1-4.0, and contains a THF-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting a main peak in a molecular weight range of 4000-9000, including 35.0-65.0% (A1) of a component haing molecular weights in a range of 500 to below 1.times.10.sup.4, 25.0-45.0% (A2) of a component having molecular weights in a range of 1.times.10.sup.4 to below 1.times.10.sup.5 and 10.0-30.0% (A3) of a component having molecular weights of at least 1.times.10.sup.5 giving a ratio A1/A2 of 1.05-2.00. The binder resin shows good dispersibility of wax and colorant.

Toner and image forming method

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Kawasaki, Japan

Minekazu Endo