# US 2019/0171122 A1 · Toner, toner storage unit, image forming apparatus, and image forming method

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- Number: US 2019/0171122 A1
- Document ID: US20190171122A1
- Status: Published application
- Kind: A1
- Application number: 16/199,321
- Filed: 2018-11-26
- Published: 2019-06-06
- Earliest claimed: 2017-12-05
- Assignees: Ricoh Company, Ltd.
- Inventors: Masayuki UKIGAYA; Junichi AWAMURA; Hiroshi YAMADA; Kohsuke NAGATA; Hiroyuki TAKEDA
- Web page: https://patentgrep.com/patent/US20190171122A1

## CPC

- G03G 9/08755: {Polyesters}
- G03G 9/08764: {Polyureas; Polyurethanes}
- G03G 9/08795: {characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants}
- G03G 9/08797: {characterised by their physical properties, e.g. viscosity, solubility, melting temperature, softening temperature, glass transition temperature}
- G03G 15/0865: {Arrangements for supplying new developer}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

A toner is provided. The toner comprises a colorant, a release agent, and a binder resin. The binder resin comprises a crystalline polyester resin and an amorphous polyester resin. The amorphous polyester resin comprises an amorphous polyester resin A and an amorphous polyester resin B. The amorphous polyester resin A comprises an isocyanurate backbone and at least one of urethane bond and urea bond. The amorphous polyester resin B comprises a trimellitic acid backbone and at least one of urethane bond and urea bond.

## Claims

### Claim 1

A toner comprising:
a colorant;
a release agent; and
a binder resin comprising:
a crystalline polyester resin; and
an amorphous polyester resin comprising:
an amorphous polyester resin A comprising an isocyanurate backbone and at least one of urethane bond and urea bond; and
an amorphous polyester resin B comprising a trimellitic acid backbone and at least one of urethane bond and urea bond.

### Claim 2 (depends on 1)

The toner of claim 1, wherein the amorphous polyester resin A comprises a structure represented by any one of the following structural formulae 1) to 3):
1) R1-(NHCONH—R2)n-;
2) R1-(NHCOO—R2)n-; and
3) R1-(OCONH—R2)n-,
where n represents an integer of 3, R1 represents an isocyanurate backbone, and R2 represents a group derived from a polyester comprising a polycarboxylic acid and a polyol or from an isocyanate-modified polyester.

### Claim 3 (depends on 1)

The toner of claim 1, wherein the toner has a parameter T1/2 of from 105° C. to 125° C., the parameter T1/2 measured according to a temperature rising method by a flow tester.

### Claim 4 (depends on 1)

The toner of claim 1, wherein the toner has a glass transition temperature (Tg1st (toner)) of from 50° C. to 65° C., the glass transition temperature (Tg1st (toner)) determined from an endothermic curve obtained in a first temperature rising in a measurement by a differential scanning calorimeter.

### Claim 5 (depends on 1)

A toner storage unit comprising:
a container; and
the toner of claim 1 stored in the container.

### Claim 6 (depends on 1)

An image forming apparatus comprising:
an electrostatic latent image bearer;
an electrostatic latent image forming device configured to form an electrostatic latent image on the electrostatic latent image bearer; and
a developing device containing the toner of claim 1, configured to develop the electrostatic latent image formed on the electrostatic latent image bearer with the toner to form a visible image.

### Claim 7 (depends on 1)

An image forming method comprising:
charging an electrostatic latent image bearer;
forming an electrostatic latent image on the charged electrostatic latent image bearer;
developing the electrostatic latent image bearer into a toner image with the toner of claim 1;
primarily transferring the toner image formed on the electrostatic latent image bearer onto an intermediate transfer medium;
secondarily transferring the toner image transferred onto the intermediate transfer medium onto a recording medium;
fixing the toner image on the intermediate transfer medium by application of heat and pressure; and
removing residual toner particles remaining on the electrostatic latent image bearer after the toner image has been transferred onto the intermediate transfer medium.

### Claim 8 (depends on 7)

The image forming method of claim 7, wherein, in the secondarily transferring, the toner imager is transferred onto the recording medium at a linear velocity of from 100 to 1,000 mm/sec and a transfer time of from 0.5 to 60 msec.