# US 11,906,928 B2 · Electrostatic charge image developing toner, electrostatic charge image developer, toner cartridge, process cartridge, and image forming apparatus

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- Number: US 11,906,928 B2
- Document ID: US11906928B2
- Status: Granted
- Kind: B2
- Application number: 17/400,203
- Filed: 2021-08-12
- Published: 2022-11-24
- Granted: 2024-02-20
- Earliest claimed: 2021-05-24
- Assignees: FUJIFILM Business Innovation Corp.
- Applicants: FUJIFILM Business Innovation Corp.
- Inventors: Shintaro Anno; Yoshimasa Fujihara; Atsushi Sugawara; Daisuke Noguchi; Satoshi Miura
- Web page: https://patentgrep.com/patent/US11906928B2

## CPC

- G03G 9/09708: {Inorganic compounds}
- 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 9/08755: {Polyesters}
- G03G 9/0902: {Inorganic compounds}
- G03G 9/09716: {treated with organic compounds}
- G03G 9/09725: {Silicon-oxides; Silicates}
- G03G 15/08: using a solid developer, e.g. powder developer
- G03G 21/1814: {Details of parts of process cartridge, e.g. for charging, transfer, cleaning, developing (G03G21/1835 takes precedence)}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

An electrostatic charge image developing toner includes: a toner particle containing a binder resin; and an external additive containing alumina particles having a volume average particle diameter of more than 5 nm and 80 nm or less and silica particles having a volume average particle diameter of 10 nm or more and 90 nm or less, and in the toner particle, a Net intensity NA of a total of an alkali metal element and an alkaline earth metal element, measured by fluorescence X-ray analysis, is 0.10 kcps or more and 1.30 kcps or less, and a ratio (Ws/Wa) of a content Ws of the silica particles to a content Wa of the alumina particles is more than 0.5 and less than 35.

## Claims

### Claim 1

An electrostatic charge image developing toner comprising:
a toner particle containing a binder resin; and
an external additive containing:
alumina particles having a volume average particle diameter of more than 5 nm and 80 nm or less; and
silica particles having a volume average particle diameter of 10 nm or more and 90 nm or less,
wherein in the toner particle,
a Net intensity NA of a total of an alkali metal element and an alkaline earth metal element, measured by fluorescence X-ray analysis, is 0.10 kcps or more and 1.30 kcps or less,
the alkali metal element and the alkaline earth metal element contain at least one selected from the group consisting of Na, Mg, and Ca, and
a ratio (Ws/Wa) of a content Ws of the silica particles to a content Wa of the alumina particles is more than 0.5 and less than 35.

### Claim 2 (depends on 1)

The electrostatic charge image developing toner according to claim 1,
wherein the Net intensity NA is 0.20 kcps or more and 1.00 kcps or less.

### Claim 3 (depends on 1)

The electrostatic charge image developing toner according to claim 1,
wherein the alkali metal element and the alkaline earth metal element contain at least one selected from the group consisting of Na and Mg.

### Claim 4 (depends on 1)

The electrostatic charge image developing toner according to claim 1,
wherein in the toner particle, a Net intensity Ns of S element measured by fluorescence X-ray analysis is 3.0 kcps or more and 6.0 kcps or less.

### Claim 5 (depends on 4)

The electrostatic charge image developing toner according to claim 4,
wherein a ratio (Ns/NA) of the Net intensity Ns to the Net intensity NA is more than 3 and less than 40.

### Claim 6 (depends on 1)

The electrostatic charge image developing toner according to claim 1,
wherein the binder resin contains an amorphous polyester resin and a crystalline polyester resin.

### Claim 7 (depends on 6)

The electrostatic charge image developing toner according to claim 6,
wherein the crystalline polyester resin is a polymer of an α,ω-linear aliphatic dicarboxylic acid and an α,ω-linear aliphatic diol.

### Claim 8 (depends on 1)

The electrostatic charge image developing toner according to claim 1,
wherein a ratio of the volume average particle diameter of the silica particles to the volume average particle diameter of the alumina particles is 0.2 or more and 2.0 or less.

### Claim 9 (depends on 1)

The electrostatic charge image developing toner according to claim 1,
wherein in X-ray photoelectron spectroscopy (XPS) before an ultrasonic treatment, a detection amount of Si relative to a detection amount of Al is 3.0 or more and 10.5 or less, and
in X-ray photoelectron spectroscopy (XPS) after the ultrasonic treatment, the detection amount of Si relative to the detection amount of Al is 2.5 or more and 8.5 or less.

### Claim 10 (depends on 1)

An electrostatic charge image developer comprising the electrostatic charge image developing toner according to claim 1.

### Claim 11 (depends on 1)

A toner cartridge that accommodates the electrostatic charge image developing toner according to claim 1 and is detachable from an image forming apparatus.

### Claim 12 (depends on 10)

A process cartridge comprising a developing unit that accommodates the electrostatic charge image developer according to claim 10 and develops an electrostatic charge image formed on a surface of an image carrier as a toner image by the electrostatic charge image developer, the process cartridge being detachable from an image forming apparatus.

### Claim 13 (depends on 10)

An image forming apparatus, comprising:
an image carrier;
a charging unit that charges a surface of the image carrier;
an electrostatic charge image forming unit that forms an electrostatic charge image on the charged surface of the image carrier;
a developing unit that accommodates the electrostatic charge image developer according to claim 10 and develops the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer;
a transfer unit that transfers the toner image formed on the surface of the image carrier to a surface of a recording medium; and
a fixing unit that fixes the toner image transferred to the surface of the recording medium.

### Claim 14 (depends on 2)

The electrostatic charge image developing toner according to claim 2,
wherein the alkali metal element and the alkaline earth metal element contain at least one selected from the group consisting of Na and Mg.