Electrostatic image developing toner and two-component developer

Abstract

The present invention provides an electrostatic image developing toner capable of improving the dispersibility of wax in the toner and superior in offset resistance and in storageability (heat-resistant storageability) at high temperatures, and a two-component developer which uses this electrostatic image developing toner. The electrostatic image developing toner includes: a binder resin, a colorant, and a release agent, wherein the binder resin contains a polyester resin, and a block copolymer which has a polyolefin backbone unit.

Description

technical field [0001] The present invention relates to an electrostatic image developing toner and a two-component developer. Background technique [0002] In electrophotographic image forming apparatuses, a contact type thermal fixing method such as a heat roller fixing method is widely used. Such as figure 1 As shown, a fixing device 10 for the heat roller fixing method includes a heat roller 11 and a pressure roller 12; The unfixed image is fused and fixed on the recording paper 21 at the portion (nip portion) that is in contact with each other under pressure. [0003] The problem with the contact type thermal fixing method typified by the thermal roller fixing method is that since the unfixed toner image on the recording paper 21 is brought into contact with the surface of the heating member such as the heating roller 11, the unfixed toner image to be fixed on the recording paper 21, so that part of the unfixed toner adheres to the heating roller 11, and when the hea...

AI Technical Summary

Problems solved by technology

However, for toners for developing electrostatic latent images (also simply referred to as "toner"), especially for oil-free fixing devices suitable for use in fixing parts such as heating parts and pressing parts that do not require fixing oil Toner for oil fixing, when only the particle size of the wax is adjusted, there is the above limitation

For example, for a toner in which the particle size distribution peak of the wax is shifted toward a relatively small particle size, the amount of wax components with medium and large particle sizes is relatively small, so that there is a problem of insufficient improvement in paper separation and fixability at the time of oil-free fixing. question

In addition, for toners whose particle size distribution peaks of waxes are shifted toward larger particle sizes, there is a problem of maintaining a balance between improvements in paper separation and fixability and reduction in image noise in a completely oil-free fixing system

[0011] For toners in which polyolefin-based resins are added to the partial binder resin, the partial binder resin is modified to improve its affinity for wax; however, if a low-polarity paraffin is used, the dispersibility of the wax Insufficient, so that as in the case of the above-mentioned toner, there are toner properties such as offset resistance, separation between recording paper and fixing member, high-temperature storage, and filming resistance caused by the dispersibility of wax The problem of insufficient improvement

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