Electrostatic image developing toner, toner kit and image forming apparatus

A toner kit, comprising a toner,

• wherein the toner kit comprises a colorant and a binder resin,
• the binder resin comprises a polyester resin that is prepared by a polycondensation reaction of a polyol and a polycarboxylic acid in the presence of at least a titanium-containing catalyst expressed by General Formula (I) or (II), wherein an amount of the titanium-containing catalyst in the polycondensation reaction is from 0.0001 to 0.8% by mass based on the resulting polycondensation product in view of polymerization activity,
• wherein the polyol and the polycarboxylic acid are reacted in a ratio of polyol/polycarboxylic acid of from 2/1 to 1/2 in terms of equivalent ratio [OH]/[COON];
• the toner has a volume average particle diameter of 2.0 μm to 10.0 μm and a ratio Dv/Dn of 1.00 to 1.40, in which Dv represents a volume average particle diameter and Dn represents a number average particle diameter,
• Ti(—X)m(—OH)n General Formula (I)
• O═Ti(—X)p(—OR)q General Formula (II)
• in General Formulas (I) and (II), X represents a residue of a mono-alkanolamine of 2 to 12 carbon atoms or a polyalkanolamine from which a hydrogen atom of one hydroxyl group is removed;
• other hydroxyl group(s) and still other hydroxyl group(s), within the polyalkanolamine molecule that has a directly bonding Ti atom, may polycondense to form a ring structure;
• other hydroxyl group(s) and still other hydroxyl group(s) may polycondense intermolecularly to form a repeating structure;
• and the polymerization degree is 2 to 5 in a case of forming the repeating structure;
• R represents one of a hydrogen atom and alkyl groups of 1 to 8 carbon atoms that may have 1 to 3 ether bonds;
• “m” is an integer of 1 to 4;
• “n” is an integer of 0 to 3;
• the sum of “m” and “n” is 4;
• “p” is an integer of 1 or 2;
• “q” is an integer of 0 or 1;
• the sum of “p” and “q” is 2;
• and in a case that “m” and “p” is 2 or more, the respective Xs may be identical or different each other;
• wherein the toner kit comprises a yellow toner, a magenta toner and a cyan toner,
• the magenta toner comprises an organic pigment expressed by the following Structural Formula (1), and the yellow toner comprises an organic pigment having two units per molecule each expressed by Structural Skeleton (A) and no halogen atom;
• in the Structural Formula (1) and Structural Skeleton (A), ═C═N—NH— may be ═CH—N═N—.

An image forming apparatus, comprising:

• a latent electrostatic image bearing member,
• a latent electrostatic image forming unit configured to form a latent electrostatic image on the latent electrostatic image bearing member,
• at least three developing units configured to develop a visible image using a toner kit,
• a transfer unit configured to transfer the visible image onto a recording medium, and
• a fixing unit configured to fix the transferred image on the recording medium,
• wherein the toner kit comprises a toner that comprises a colorant and a binder resin,
• the binder resin comprises a polyester resin that is prepared by a polycondensation reaction of a polyol and a polycarboxylic acid in the presence of at least a titanium-containing catalyst expressed by General Formula (I) or (II) , wherein an amount of the titanium-containing catalyst in the polycondensation reaction is from 0.0001 to 0.8% by mass based on the resulting polycondensation product in view of polymerization activity,
• wherein the polyol and the polycarboxylic acid are reacted in a ratio of polyol/polycarboxylic acid of from 2/1 to 1/2 in terms of equivalent ratio [OH]/[COOH];
• the toner has a volume average particle diameter of 2.0 μm to 10.0 μm and a ratio Dv/Dn of 1.00 to 1.40, in which Dv represents a volume average particle diameter and Dn represents a number average particle diameter,
• Ti(—X)m(—OH)n General Formula (I)
• O═Ti(—X)p(—OR)q General Formula (II)
• in General Formulas (I) and (II), X represents a residue of a mono-alkanolamine of 2 to 12 carbon atoms or a polyalkanolamine from which a hydrogen atom of one hydroxyl group is removed;
• other hydroxyl group(s) and still other hydroxyl group(s), within the polyalkanolamine molecule that has a directly bonding Ti atom, may polycondense to form a ring structure;
• other hydroxyl group(s) and still other hydroxyl group(s) may polycondense intermolecularly to form a repeating structure;
• and the polymerization degree is 2 to 5 in a case of forming the repeating structure;
• R represents one of a hydrogen atom and alkyl groups of 1 to 8 carbon atoms that may have 1 to 3 ether bonds;
• “m” is an integer of 1 to 4;
• “n” is an integer of 0 to 3;
• the sum of “m” and “n” is 4;
• “p” is an integer of 1 or 2;
• “q” is an integer of 0 or 1;
• the sum of “p” and “q” is 2;
• and in a case that “m” and “p” is 2 or more, the respective Xs may be identical or different each other;
• wherein the toner kit comprises a yellow toner, a magenta toner and a cyan toner,
• the magenta toner comprises an organic pigment expressed by the following Structural Formula (1), and the yellow toner comprises an organic pigment having two units per molecule each expressed by Structural Skeleton (A) and no halogen atom;
• in the Structural Formula (1) and Structural Skeleton (A), ═C═N—NH— may be ═CH—N═N—.