Resin for toner and toner

Abstract

A resin for toner containing a resin component having both a polyester unit produced by polycondensation of a polyhydric alcohol component and a polycarboxylic acid component, and an aryl group having a sulfonic ester group as a substituent; and a toner that contains the resin for toner.

Description

[0001] This application is a continuation of International Application No. PCT / JP2006 / 322909, filed Nov. 10, 2006, which claims the benefit of Japanese Patent Application No. 2005-327142, filed Nov. 11, 2005.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a resin for toner contained in a toner used in an image forming method utilizing electrophotography or electrostatic printing or toner jet image forming method. In particular, the present invention relates to a resin for toner contained in a toner to be provided in a fixing method that involves fixing a toner image formed by the toner on a print sheet such as a transfer material under heat and pressure. Further, the present invention relates to a toner that contains the resin for toner. [0004] 2. Related Background Art [0005] Conventionally, the image forming process utilizing electrophotography, electrostatic printing and so on is constructed such that an electrostatic latent im...

AI Technical Summary

Benefits of technology

[0023] That is, it is an object of the present invention to provide a toner having a good fixability and charging properties.

[0024] It is another object of the present invention to provide a toner that can provide stable images from an initial stage to after printing out a large number of sheets.

[0025] As a result of extensive investigation, the inventors of the present invention have found that the charging performance of a toner can be improved and a resin for toners having excellent fixability, development and transfer properties can be obtained by attaching an aryl group having a sulfonic ester group as a substituent to a resin having a polyester unit. The present invention has been achieved based on this finding.

[0027] Use of the resin for toner according to the present invention allows for providing a toner that has a good low temperature fixability and a stable triboelectric chargeability, excellent developability and transferability, and is capable of providing a stable image for long period of time.

Problems solved by technology

In this case, toners are charged by friction between toners or between a toner and a carrier, and further due to friction with a control blade.

However, binder resins commonly used for toners have low triboelectric properties so that it is difficult to control the chargeability by the composition of the binder resin.

Those charge control agents have complex structures and are variable in their property and many of them have poor stability; in particular, most of them vary in chargeability depending on their environment such as temperature and humidity.

For this reason, the friction between the toners, collision of the toner with the carrier, friction of the toner with a conveyor sleeve, a roller, a control blade, a photosensitive drum or the like makes the charge control agent to come off from the surface of the toner, which may cause contamination of the carrier and so on, and contamination of a developing member, the photosensitive drum and so on.

In this case, an increasing printing number of sheets leads to a decreased chargeability and results in progression of deterioration of peripheral members and causes problems such as a change in image density and a decrease in image quality.

In this case, if a further improvement of low temperature performance is attempted, chargeability in addition to storage stability and flowability tends to be deteriorated; in particular, when continuous printing is performed, a remarkable decrease in image density or a faulty image tends to occur.

That is, in the case of the toner having a small particle size, failure to impart uniform charge quantity to individual toner particles results in a remarkable decrease in image stability.

(2) A decrease in toner particle size is accompanied by deterioration of flowability, so that the charge quantity of individual toner particles tends to be non-uniform, thus causing fog or a decrease in transferability.

However, studies on the toners performed by the inventors of the present invention reveal that when the number of printouts becomes larger, toners of opposite polarity gradually increase in the developing device, which leads to a problem that so-called reversal fog tends to occur.

However, there is room for improvement of charging properties, and in particular, the stability of charge quantity under high temperature and high humidity conditions was insufficient.

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