Intermediate image transfer device for a color image forming apparatus

A direct image transfer type of image forming apparatus comprising:

• an image carrier;
• a belt conveyor;
• and
• image transferring means for transferring a toner image formed on said image carrier to a recording medium being conveyed by said belt conveyor, said image transferring means comprising bias applying means for applying an image transfer bias to a reverse surface of said belt conveyor opposite to a surface conveying said recording medium;
• wherein when a surface resistivity of said belt conveyor is measured by a method that repeatedly applies a voltage v1 of 200 V for a period of time t1 of 60 seconds to said belt conveyor and grounds said belt conveyor for a period of time t2 of 10 seconds a number of times N1 of 1,000, a difference in absolute value between a logarithm of a first time of measurement and logarithm of a thousandth time of measurement is 0.5 log Ω/□ or below.

An intermediate image transfer type of image forming apparatus comprising:

• an image carrier;
• an intermediate image transfer body to which a toner image is transferred from said image carrier;
• primary image transferring means for transferring the toner image from said image carrier to said intermediate image transfer body;
• and
• secondary image transferring means for transferring the toner image from said intermediate image transfer body to a recording medium;
• wherein said primary image transferring means comprises primary bias applying means for applying a primary image transfer bias to said intermediate image transfer body, and
• wherein said intermediate image transfer body has a surface potential attenuation ratio that attenuates, before a portion of said intermediate image transfer body applied with the primary image transfer bias is subject to a next primary image transfer, a potential remaining on said portion to a degree not disturbing said next primary image transfer.

An intermediate image transfer type of image forming apparatus comprising:

• an image carrier;
• an intermediate image transfer body to which a toner image is transferred from said image carrier;
• primary image transferring means for transferring the toner image from said image carrier to said intermediate image transfer body;
• and
• secondary image transferring means for transferring the toner image from said intermediate image transfer body to a recording medium;
• wherein said primary image transferring means comprises primary bias applying means for applying a primary image transfer bias to said intermediate image transfer body,
• wherein said secondary image transferring means comprises secondary bias applying means for applying a secondary image transfer bias to said intermediate image transfer body, and
• wherein said intermediate image transfer body has a surface potential attenuation ratio that attenuates, before a portion of said intermediate image transfer body applied with the secondary image transfer bias is subject to a next primary image transfer, a potential remaining on said portion to a degree not disturbing said next primary image transfer.