Transparent toner for developing electrostatic latent image, electrostatic latent image developer, toner cartridge, process cartridge, image forming apparatus and image forming method
View Patent ↗The invention provides a transparent toner for developing an electrostatic latent image, including a binder resin and a release agent, the difference between the endothermic peak Tm of the release agent in a temperature increasing process and the exothermic peak Tc of the release agent in a temperature decreasing process being from about 10° C. to about 50° C., where Tm and Tc are measured with a differential scanning calorimeter (DSC) according to the ASTM method.
1. A transparent toner for developing an electrostatic latent image, comprising
a binder resin; and
a release agent having a domain, and Al being present inside the domain of the release agent, the difference between the endothermic peak Tm of the release agent in a temperature increasing process and the exothermic peak Tc of the release agent in a temperature decreasing process being from about 10° C. to about 50° C., where Tm and Tc are measured with a differential scanning calorimeter (DSC) according to the ASTM method, wherein:
the binder resin is a polyester resin having an acid value from about 3.0 mg KOH/g to about 30.0 mg KOH/g;
the release agent has a melting temperature ranging from 90° C. to 115° C.; and
the transparent toner has a colorant content of about 0.01% by weight or less.
2. The transparent toner for developing an electrostatic latent image according to claim 1 , wherein the melting temperature of the polyester resin is from about 50° C. to about 100° C.
3. The transparent toner for developing an electrostatic latent image according to claim 1 , wherein the polyester resin comprises a diol component which is a linear-chain aliphatic diol having about 7 to about 20 carbon atoms in the main chain structure thereof.
4. The transparent toner for developing an electrostatic latent image according to claim 1 , wherein the weight average molecular weight (Mw) of the polyester resin is from about 6,000 to about 35,000.
5. The transparent toner for developing an electrostatic latent image according to claim 1 , wherein the content of Al in the domain of the release agent as measured by X ray fluorescence spectrometry is from about 0.005 atom % to about 0.1 atom %.
6. The transparent toner for developing an electrostatic latent image according to claim 1 , wherein the content of the release agent in the toner is from about 0.5% by weight to about 15% by weight.
7. The transparent toner for developing an electrostatic latent image according to claim 1 , wherein the volume average particle diameter of the toner is from about 4 μm to about 9 μm.
8. The transparent toner for developing an electrostatic latent image according to claim 1 , wherein the shape factor SF 1 of the toner is from about 110 to about 140.
9. An electrostatic latent image developer comprising the transparent toner for developing an electrostatic latent image according to claim 1 and a carrier.
10. The electrostatic latent image developer according to claim 9 , wherein the carrier comprises a white conductive material.
11. A toner cartridge that is attachable to and detachable from an image forming apparatus and comprises the transparent toner for developing an electrostatic latent image according to claim 1 to be fed to a developing unit arranged in the image forming apparatus.
12. A process cartridge comprising at least a developer-holding member and comprising the electrostatic latent image developer according to claim 9 .
13. An image forming apparatus comprising:
a latent image-holding member,
a developing unit that develops an electrostatic latent image formed on the latent image-holding member as a toner image comprising the electrostatic latent image developer according to claim 9 ,
a transfer unit that transfers the toner image formed on the latent image-holding member onto a receiving material, and
a fixing unit that fixes the toner image transferred onto the receiving material.
14. An image forming method comprising
forming an electrostatic latent image on a latent image-holding member,
developing the electrostatic latent image formed on the latent image-holding member as a toner image using the electrostatic latent image developer according to claim 9 held on a developer-holding member,
transferring the toner image formed on the latent image-holding member onto a receiving material, and
fixing the toner image transferred onto the receiving material, where the shape factor SF 1 of a domain of a release agent on a cross section of the fixed toner image is from about 100 to about 140.