Electrophotographic belt and electrophotographic image-forming apparatus

An electrophotographic image-forming apparatus comprising:

• an electrophotographic photosensitive member;
• an intermediate transfer belt to which a toner image formed on the electrophotographic photosensitive member is primary-transferred;
• and
• a secondary transfer device for secondary-transferring the toner image transferred to the intermediate transfer belt to a recording medium,
• wherein the intermediate transfer belt is an electrophotographic belt,
• the electrophotographic belt includes a base layer that contains a binder resin and carbon black in the binder resin,
• the binder resin contains at least one resin selected from the group consisting of PEEK and PPS, and
• a water content calculated by ((X2−X1)/X2)×100 is 0.6% or more,
• where X1 is a mass of a specimen cut out of the base layer when in a nitrogen atmosphere a temperature of the specimen is increased from a temperature of 30° C. to a temperature of 100° C. at a rate of 20° C. per min in a nitrogen atmosphere and the temperature is maintained at 100° C. for 30 min, and
• X2 is a mass of the specimen when in a nitrogen atmosphere the specimen is thereafter cooled from a temperature of 100° C. to a temperature of 30° C. at a rate of 20° C. per min and the specimen is left to stand in the air under an environment of a temperature of 23° C. and a relative humidity of 50% for 48 hours,
• wherein the carbon black has:
• a primary particle diameter of 15 nm or more and less than 35 nm, and
• a water absorption rate determined through steps (i) to (iii) and calculation formula (1) is 0.7% or more,
• step (i):
• carbon black is fired in a nitrogen atmosphere at a temperature of 430° C. for 6 hours so as to prepare heat-treated carbon black,
• step (ii):
• the resulting heat-treated carbon black is left to stand under the condition of a temperature of 23° C. and a relative humidity of 50% for 48 hours, and thereafter a mass (W0) is measured using a thermogravimetric analyzer (TGA), and
• step (iii):
• a temperature of the heat-treated carbon black after the mass (W0) is measured is increased from a temperature of 30° C. to a temperature of 120° C. at a rate of 20° C. per min in a nitrogen atmosphere, the temperature is maintained at 120° C. for 15 min, and a mass (W1) is measured also using the thermogravimetric analyzer (TGA),
• [(W0-W1)/W0]×100 (1)
• wherein a content of the carbon black in the base layer is 15% by mass or more and 30% by mass or less relative to the mass of the base layer.