Toner for developing electrostatic image

Claim 2

A toner for developing an electrostatic image, comprising toner particles wherein said toner particles comprise at least a binder resin, a colorant, a polar resin and a release agent; wherein said polar resin has at least one terminal group which has been modified by a polycarboxylic acid having at least three carboxyl groups, said polar resin having an acid value of 3-35 mgKOH/g.

Claim 3

The toner according to claim 1, wherein said polar resin comprises a polyester resin.

Claim 4

The toner according to claim 2, wherein said polyester resin has an acid value of 4-35 mgKOH/g and has a number-average molecular weight (Mn) of 3,000-15,000, a weight-average molecular weight (Mw) of 6,000-50,000, and an Mw/Mn of 1.2-3.0 based on GPC.

Claim 5

The toner according to claim 3, wherein said polyester resin has a number-average molecular weight (Mw(cal.)) obtained from the following formula: Mn(cal.)=56.108×2000/ (acid value of polyester resin)+(OH value of polyester resin)!, Mn and Mn(cal.) providing a difference therebetween Mn-Mn(cal.)! of at least 500.

Claim 6

The toner according to claim 3, wherein said polar resin comprises a polyester resin obtained from a diol having a bisphenol structure and a dicarboxylic acid.

Claim 7

The toner according to claim 3, wherein said polar resin comprises a polyester resin obtained from a bisphenol A-based diol, a dicarboxylic acid and a polycarboxylic acid.

Claim 8

The toner according to claim 1, wherein said binder resin comprises a polystyrene, a styrene copolymer or a mixture thereof.

Claim 9

The toner according to claim 1, wherein said binder resin comprises a styrene-acrylate copolymer.

Claim 10

The toner according to claim 1, wherein said binder resin comprises a styrene-methacrylate copolymer.

Claim 11

The toner according to claim 1, wherein said toner particles are formed by dispersing a polymerizable monomer composition comprising at least a polymerizable monomer, a colorant, a polar resin, a release agent, and a polymerization initiator in an aqueous medium, forming the polymerizable monomer composition into particles, and polymerizing the polymerizable monomer.

Claim 12

The toner according to claim 3, wherein said polyester resin has an acid value of 5-30 mgKOH/g.

Claim 13

The toner according to claim 3, wherein said polyester resin has an OH value of 5-50 mgKOH/g.

Claim 14

The toner according to claim 12, wherein said polyester resin has an OH value of 7-45 mgKOH/g.

Claim 15

The toner according to claim 3, wherein said polyester resin has an acid value of 5-30 mgKOH/g and an OH value of 7-45 mgKOH/g.

Claim 16

The toner according to claim 3, wherein said polyester resin has an Mn of 3,500-12,000, an Mw of 6,500-45,000, and an Mw/Mn of 1.5-2.5.

Claim 17

The toner according to claim 3, wherein said polyester resin has a main peak in a molecular weight region of 4,500-22,000 in a molecular weight distribution according to GPC.

Claim 18

The toner according to claim 16, wherein said polyester resin has a main peak in a molecular weight region of 6,000-20,000 in a molecular weight distribution according to GPC.

Claim 19

The toner according to claim 1, wherein said polar resin has a glass transition point (Tg) of 50°-95° C.

Claim 20

The toner according to claim 18, wherein said polar resin has a Tg of 55°-90° C.

Claim 21

The toner according to claim 1, wherein said polar resin has an acid value of 0.1-30 mgKOH/g and an OH value of 7-55 mgKOH/g, respectively, before the modification by the polycarboxylic acid.

Claim 22

The toner according to claim 20, wherein said polar resin has an acid value of 1.0-28 mgKOH/g and an OH value of 10-50 mgKOH/g, respectively, before the modification by the polycarboxylic acid.

Claim 23

The toner according to claim 1, wherein said polar resin comprises a polyester resin formed by modifying a linear polyester resin with a polycarboxylic acid having at least three carboxylic groups.

Claim 24

The toner according to claim 22, wherein said polyester resin has an MW/Mn of 1.2-3.0.

Claim 25

The toner according to claim 23, wherein said polyester resin has an Mw/Mn of 1.5-2.5.

Claim 26

The toner according to claim 22, wherein said polar resin comprises a polyester resin formed by modifying a linear polyester resin obtained from an esterified bisphenol A and a terephthalic acid with trimellitic anhydride or pyromellitic anhydride.

Claim 27

The toner according to claim 1, wherein said release agent has an Mw of 350-4,000 and an Mn of 200-4,000.

Claim 28

The toner according to claim 26, wherein said release agent has an Mw of 400-3,500 and an Mn of 250-3,500.

Claim 29

The toner according to claim 1, wherein said release agent has a melting point of 30°-120° C.

Claim 30

The toner according to claim 28, wherein said release agent has a melting point of 50°-90° C.

Claim 31

The toner according to claim 1, wherein said release agent comprises a solid wax.

Claim 32

The toner according to claim 30, wherein said release agent comprises a solid wax having a melting point of 50°-90° C.

Claim 33

The toner according to claim 1, wherein said release agent comprises a solid ester wax.

Claim 34

The according to claim 32, wherein said release agent comprises a solid ester wax having a melting point of 50°-90° C.

Claim 35

The toner according to claim 1, wherein said release agent comprises an ester wax selected from the group consisting of compounds represented by the following formulae (I)-(VI): R.sub.1 --COO--(CH.sub.2).sub.n !.sub.a --C-- (CH.sub.2).sub.m --OCO--R.sub.2 !.sub.b (I), wherein aand b independently denote an integer of 0-4 satisfying a+b=4; R 1 and R 2 independently denote an organic group having 1-40 carbon atoms, R 1 and R 2 providing a difference in carbon number of at least 3; and m and n independently denote an integer of -25 with the proviso that m and n are not 0 at the same time; ##STR6## wherein aand b independently denote an integer of 0-3 satisfying a+b=1-3; R 1 and R 2 independently denote an organic group having 1-40 carbon atoms, R 1 and R 2 providing a difference in carbon number of at least 3; R 3 denotes hydrogen atom or an organic group having at least one carbon atom with the proviso that one of R 3 is an organic group having at least one carbon atom when a+b=2; k is an integer of 1-3; and m and n independently denote an integer of 0-25 with the proviso that m and n are not 0 at the same time; R.sub.1 --OCO--R.sub.2 --COO--R.sub.3 (III), wherein R 1 and R 3 independently denote an organic group having 6-32 carbon atoms, and R 2 denotes an organic group having 1-20 carbon atoms; R.sub.1 --COO--R.sub.2 --OCO--R.sub.3 (IV), wherein R 1 and R 3 independently denote an organic group having 6-32 carbon atoms; and R 2 denotes --CH 2 CH 2 OC 6 H 4 OCH 2 CH 2 --, --(CH(CH 3 )CH 2 O) m --C 6 H 4 C(CH 3 ) 2 C 6 H 4 --(OCH 2 CH(CH 3 )) m -- or --(CH 2 ) n -- wherein m is an integer of 1-10 and n is an integer of 1-20; R.sub.1 --COO--(CH.sub.2).sub.n !.sub.a --C-- (CH.sub.2).sub.m --OH!.sub.b(V), wherein a is an integer of 0-4 and b is an integer of 1-4 satisfying a+b=4; R 1 denotes an organic group having 1-40 carbon atoms; and m and n independently denote an integer of 0-25 with the proviso that m and n are not 0 at the same time; and R.sub.1 --COO--R.sub.2 (VI), wherein R 1 and R 2 independently denote a hydrocarbon group having 15-45 carbon atoms.

Claim 36

The toner according to claim 1, wherein said polar resin is contained in an amount of 0.1-25 wt. parts per 100 wt. parts of the binder resin and said release agent is contained in an amount of 5-40 wt. parts per 100 wt. parts of the binder resin.

Claim 37

The toner according to claim 35, wherein said polar resin is contained in an amount of 0.5-20 wt. parts per 100 wt. parts of the binder resin and said release agent is contained in an amount of 10-30 wt. parts per 100 wt. parts of the binder resin.

Claim 38

The toner according to claim 36, wherein said polar resin is contained in an amount of 1-15 wt. parts per 100 wt. parts of the binder resin.

Claim 39

The toner according to claim 1, which has a shape factor SF-1 of 100 to 150.

Claim 40

The toner according to claim 3, which has a shape factor SF-1 of 100 to 150.

Claim 41

The toner according to claim 1, which has a shape factor SF-1 of 100 to 125.

Claim 42

The toner according to claim 3, which has a shape factor SF-1 of 100 to 125.

Claim 43

A process for producing a toner containing toner particles, comprising: dispersing a polymerizable monomer composition comprising at least a polymerizable monomer, a colorant, a polar resin, a release agent, and a polymerization initiator in an aqueous medium, forming the polymerizable monomer composition into particles, and polymerizing the polymerizable monomer to form the toner particles, wherein said polar resin has at least one terminal group which has been modified by a polycarboxylic acid having at least three carboxyl groups, said polar resin having an acid value of 3-35 mgKOH/g.

Claim 44

A process for producing a toner containing toner particles, comprising: dispersing a polymerizable monomer composition comprising at least a polymerizable monomer, a colorant, a polar resin, a release agent, and a polymerization initiator in an aqueous medium, forming the polymerizable monomer composition into particles, and polymerizing the polymerizable monomer to form the toner particles, wherein said polar resin has at least one terminal group which has been modified by a polycarboxylic acid having at least three carboxyl groups, said polar resin having an acid value of 3-35 mgKOH/g.

Claim 45

The process according to claim 42, wherein said toner is a toner according to any one of claims 2-41.

Claim 46

An image forming method comprising: forming an electrostatic latent image on a photosensitive member; developing said electrostatic latent image with a developer on a developing sleeve, while applying an alternating electric field to said developing sleeve to obtain a toner image on said photosensitive member, transferring said toner image onto a transfer-receiving member directly or via an intermediate transfer member; and hot-pressure fixing said toner image on said transfer-receiving member, wherein said toner comprises toner particles comprising at least a binder resin, a colorant, a polar resin and a release agent; and said polar resin has at least one terminal group which has been modified by a polycarboxylic acid having at least three carboxyl groups, said polar resin having an acid value of 3-35 mgKOH/g.

Claim 47

An image forming method comprising: forming an electrostatic latent image on a photosensitive member; developing said electrostatic latent image with a developer on a developing sleeve, while applying an alternating electric field to said developing sleeve to obtain a toner image on said photosensitive member, transferring said toner image onto a transfer-receiving member directly or via an intermediate transfer member; and hot-pressure fixing said toner image on said transfer-receiving member, wherein said toner comprises toner particles comprising at least a binder resin, a colorant, a polar resin and a release agent; and said polar resin has at least one terminal group which has been modified by a polycarboxylic acid having at least three carboxyl groups, said polar resin having an acid value of 3-35 mgKOH/g.

Claim 48

The image forming method according to claim 44, wherein said toner is a toner according to any one of claims 2-41.