# US 11,112,710 B2 · Toner and method for producing toner

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- Number: US 11,112,710 B2
- Document ID: US11112710B2
- Status: Granted
- Kind: B2
- Application number: 16/814,100
- Filed: 2020-03-10
- Published: 2020-09-17
- Granted: 2021-09-07
- Earliest claimed: 2019-03-14
- Assignees: Canon Kabushiki Kaisha
- Applicants: Canon Kabushiki Kaisha
- Inventors: Kenichi Nakayama; Takeshi Kaburagi; Shintaro Kawaguchi; Shota Amano
- Web page: https://patentgrep.com/patent/US11112710B2

## CPC

- G03G 9/08755: {Polyesters}
- G03G 9/08795: {characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants}
- G03G 9/0804: {whereby the components are brought together in a liquid dispersing medium}
- G03G 9/0819: {characterised by the dimensions of the particles}
- G03G 9/0823: {Electric parameters}
- G03G 9/0827: {characterised by their shape, e.g. degree of sphericity}
- G03G 9/08782: {Waxes}
- G03G 9/09328: {obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds}
- G03G 9/09716: {treated with organic compounds}
- G03G 9/09725: {Silicon-oxides; Silicates}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

A toner comprising: a toner particle that includes a binder resin, and an external additive, wherein the toner particle includes a polyester resin on the surface; the toner particle includes a polyvalent metal element; where an electrical resistivity of the polyvalent metal element at 20° C. is denoted by A Ω·m, and an amount of the polyvalent metal element in the toner particle is denoted by B μmol/g, a following relationship is satisfied: 0.025×108≤(1/A)×B≤4.500×108; the external additive includes silica particles; and the silica particles includes spherical silica particles having a number average particle diameter of from 20 nm to 40 nm.

## Claims

### Claim 1

A toner, comprising:
a toner particle comprising a binder resin and a polyvalent metal element;
an external additive comprising a spherical silica particle having a number average particle diameter of 20-40 nm and a circularity of 0.80 or more; and
a surface of the toner particle comprising a polyester resin, wherein
0.025×108≤(1/A)×B≤4.500×108 where A (Ω·m) is an electrical resistivity of the polyvalent metal element at 20° C., and B (μmol/g) is an amount of the polyvalent metal element in the toner particle.

### Claim 2 (depends on 1)

The toner according to claim 1, wherein the polyvalent metal element is at least one member selected from the group consisting of aluminum, iron, magnesium and calcium.

### Claim 3 (depends on 2)

The toner according to claim 2, wherein when the polyvalent metal element includes aluminum, the amount of aluminum in the toner particle is 0.080 to 0.400 μmol/g,
when the polyvalent metal element includes iron, the amount of iron in the toner particle is 0.270 to 1.250 μmol/g,
when the polyvalent metal element includes magnesium, the amount of magnesium in the toner particle is 2.000 to 20.000 μmol/g, and
when the polyvalent metal element includes calcium, the amount of calcium in the toner particle is 1.500 to 15.000 μmol/g.

### Claim 4 (depends on 1)

The toner according to claim 1, wherein a weight average molecular weight Mw of the polyester resin is 10000 to 60000; and
a concentration of ester groups in the polyester resin is 20 to 50% by mass.

### Claim 5 (depends on 1)

The toner according to claim 1, wherein the spherical silica particle is a sol-gel silica particle.

### Claim 6 (depends on 1)

The toner according to claim 1, wherein the toner particle includes wax, and
As is 5 to 40%, where As is a ratio of an area occupied by the wax in a region from the toner particle surface to a depth of 1.0 μm in cross-sectional observation of the toner using a transmission electron microscope.

### Claim 7 (depends on 1)

The toner according to claim 1, wherein the toner particle is an emulsion aggregation toner particle.

### Claim 8 (depends on 1)

The toner according to claim 1, wherein the binder resin is a polyester resin.

### Claim 9 (depends on 1)

A method for producing the toner according to claim 1, the method comprising the steps of:
aggregating fine particles of the binder resin to form aggregated particles; and
fusing the aggregated particles to obtain the toner particle.