Canon Kabushiki Kaisha

Masashi Jinbo

Hirohide Tanikawa

Hiroaki Kawakami

Tsutomu Onuma

Masatsugu Fujiwara

A toner for developing an electrostatic image is constituted by a binder resin and a hydrocarbon wax having a weight-average molecular weight of 800 to 3600. The toner is provided with good fixation characteristics including low-temperature fixability and anti-high temperature offsetting if the toner shows a storage modulus of at least 1.times.10.sup.3 dyn/cm.sup.2, a loss modulus in the range of 5.times.10.sup.2 -5.times.10.sup.4 dyn/cm.sup.2 and a ratio of loss modulus/storage modulus (loss tangent) of below 0.9 as measured under conditions of a frequency of 0.1 Hz and a temperature of 200.degree. C.; and the toner provides a DSC curve, as measured by a differential scanning calorimeter, showing an onset temperature of heat absorption of at most 105.degree. C. and a heat-absorption peak temperature in the range of 90.degree.-120.degree. C. on temperature increase, and a heat evolution peak temperature in the range of 62.degree.-75.degree. C. and a heat evolution peak intensity ratio of at least 2.times.10.sup.-3 on temperature decrease.

Toner for developing electrostatic image

A toner for developing electrostatic images is prepared from a binder resin and a hydrocarbon wax. The toner is provided with improved fixability and anti-offset characteristic by controlling the thermal characteristic of the hydrocarbon wax so as to provide a DSC (differential scanning calorimeter) curve, showing an onset temperature of heat absorption in the range of 50.degree.-110.degree. C. and at least one heat absorption peak P1 in the range of 70.degree.-130.degree. C. giving a peak temperature T.sub.P1 on temperature increase, and showing a maximum heat evolution peak temperature in the range of T.sub.P1 .+-.9.degree. C. on temperature decrease. Correspondingly, the toner provides a DSC curve showing a rising temperature of heat absorption of at least 80.degree. C., an onset temperature of heat absorption of at most 105.degree. C. and a heat absorption peak temperature in the range of 100.degree.-120.degree. C., respectively on temperature increase, and showing a heat evolution peak temperature in the range of 62.degree.-75.degree. C. and a heat evolution peak intensity ratio of at least 5.times.10.sup.-3 on temperature decrease.

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Asaka, Japan

Masashi Jinbo