The encapsulated toner for heat-and-pressure fixing of the present invention has a heat-fusible core material containing at least a thermoplastic resin and a coloring agent and a shell formed thereon so as to cover the surface of the core material. Moreover, the encapsulated toner has the following properties: 1) The glass transition temperature ascribed to the thermoplastic resin used as a main component of the heat-fusible core material is 10.degree. C. to 50.degree. C.; 2) A minimum load required for 58 compression of a particle size of the encapsulated toner is from 5 to 50 mgf, and a minimum load required for 10% compression of a particle size of the encapsulated toner is from 10 to 100 mgf, when a compressive variation of one toner particle is measured by a micro compression testing machine under the given conditions; and 3) The difference in cohesiveness before and after keeping the toner standing at 50.degree. C. for 24 hours, is not more than 10, wherein the cohesiveness is defined as the sum of values (a), (b), and (c) obtained by the following equations: (a)=(weight % of the toner remaining.times.1, on a 250 .mu.m mesh-sieve) (b)=(weight % of the toner remaining.times.0.6, and on a 149 .mu.m mesh-sieve) (c)=(weight % of the toner remaining.times.0.2, on a 74 .mu.m mesh-sieve) each of the weight % in the equations being measured by a powder property analyzer.
The present invention relates to a mono-component developing device, which develops an electrostatic latent image formed on an electrostatic latent image-supporting member with a toner having a weight-average particle size of from 4 to 10 .mu.m, a compression rate of not more than 32% and an angle of repose of not more than 38.degree., and a toner used for the mono-component developing device. Even in the case when a comparatively great stress is imposed on the toner particles, the toner of the present invention maintains superior fluidity and makes it possible to provide a high-quality image.
A toner evaluation method that enables accurate evaluation of fixation performance of toner such as low temperature fixability and offset resistance, and a toner cartridge and an image forming apparatus adopting the toner positively evaluated by the evaluation method are provided. Toner is formed into a disc-shaped pellet. After preserved at a predetermined temperature, the pellet is compressed by a predetermined amount at a constant speed. If the maximum load (compression resistance) measured during the compression is a predetermined value or below, the minimum fixing temperature of the toner is relatively low.
An electrostatic charge image developing toner comprises core particles formed by flocculating and fusion-bonding at least polyester resin particles containing wax and colorant particles, and a coating layer containing a resin formed over the core particles.
