Abstract: A combined resistance R1=Vt1/I1 (MO) of a transfer belt (61) and a recording sheet obtained when a transfer current I1 (?A) passes through the transfer belt (61) and the recording sheet upon application of a first transfer bias voltage Vt1 (V) to a transfer roller (6b) from a high-voltage power source (6f) and a combined resistance R2=Vt2/I2 (MO) of the transfer belt (61) and the recording sheet obtained when a transfer current I2 (?A) passes through the transfer belt (61) and the recording sheet upon application of a second transfer bias voltage Vt2 (V) to the transfer roller (6b) from the high-voltage power source (6f), are established to have the relationship: R2/R1=7 ?(I2)?0.5 therebetween.

Abstract: An image transfer device includes an image transfer electrode roller which is disposed face to face with a photosensitive drum with a printing sheet passing between the image transfer electrode roller and the photosensitive drum. The image transfer device is structured such that the image transfer electrode roller can be shifted back and forth along a transport direction of the printing sheet. A voltage is applied to the image transfer electrode roller to create an image transfer electric field between the image transfer electrode roller and the photosensitive drum for transferring a toner image formed on the photosensitive drum onto the printing sheet. The image transfer electrode roller is brought to one of different positions along a transport direction of the printing sheet selected according to information on properties of the printing sheet and transfers the toner image onto the printing sheet at that position.

Abstract: A combined resistance R1=Vt1/I1 (MO) of a transfer belt (61) and a recording sheet obtained when a transfer current I1 (?A) passes through the transfer belt (61) and the recording sheet upon application of a first transfer bias voltage Vt1 (V) to a transfer roller (6b) from a high-voltage power source (6f) and a combined resistance R2=Vt2/I2 (MO) of the transfer belt (61) and the recording sheet obtained when a transfer current I2 (?A) passes through the transfer belt (61) and the recording sheet upon application of a second transfer bias voltage Vt2 (V) to the transfer roller (6b) from the high-voltage power source (6f), are established to have the relationship: R2/R1=7?(I2)?0.5 therebetween.

Abstract: An image transfer device includes an image transfer electrode roller which is disposed face to face with a photosensitive drum with a printing sheet passing between the image transfer electrode roller and the photosensitive drum. The image transfer device is structured such that the image transfer electrode roller can be shifted back and forth along a transport direction of the printing sheet. A voltage is applied to the image transfer electrode roller to create an image transfer electric field between the image transfer electrode roller and the photosensitive drum for transferring a toner image formed on the photosensitive drum onto the printing sheet. The image transfer electrode roller is brought to one of different positions along a transport direction of the printing sheet selected according to information on properties of the printing sheet and transfers the toner image onto the printing sheet at that position.