Image forming apparatus with low ozone generation and improved image quality

An image forming apparatus comprising:

• a plurality of image carriers sequentially arranged in parallel with each other;
• a plurality of image forming means for respectively forming developer images on the image carriers;
• supply means for supplying a transfer material onto which the developer images are transferred;
• a conveyer belt provided so as to oppose the image carriers, for conveying the transfer material supplied from the supply means through the image carriers;
• and
• a plurality of transfer means arranged to oppose the image carriers, respectively, with the conveyer belt being interposed between the transfer means and the image carriers, for maintaining the supplied transfer material on the conveyer belt by a suction force and for respectively transferring the developer images formed on the image carriers to the transfer material conveyed by the conveyer belt;
• wherein a conveying speed V (mm/sec) of the conveyer belt, a running distance L2 (mm) of the conveyer belt from a final transfer position, at which a developer image transferred to the transfer material from the image carrier situated at a most downstream side in the conveying direction of the transfer material, to a first transfer position, at which a developer image is transferred to the transfer material from the image carrier situated at a most upstream side in the conveying direction of the transfer material, a volume resistance .rho. (.OMEGA..multidot.cm) of the conveyer belt, and a relative dielectric constant .epsilon. of the conveyer belt are set so as to satisfy a relation of
• L2/V .gtoreq.(.epsilon..multidot..epsilon..sub.0 .multidot..rho.).times.10.
• 7.

An image forming apparatus comprising:

• a plurality of image carriers sequentially arranged in parallel with each other;
• a plurality of image forming means for respectively forming developer images on the image carriers;
• supply means for supplying a transfer material onto which the developer images are transferred;
• a conveyer belt provided so as to oppose the image carriers, for conveying the supplied transfer material through the image carriers;
• and
• a plurality of transfer means for maintaining the supplied transfer material on the conveyer belt by a suction force and for transferring the developer images formed on the image carriers to the transfer material, the transfer means including a plurality of transfer members provided in planar or linear contact with the conveyer belt on a side opposite to the image carriers, and bias applying means for applying a transfer bias through the transfer members to the transfer material on the conveyer belt;
• wherein a conveying speed V (mm/sec) of the conveyer belt, a distance X (mm) between two adjacent image carriers, a volume resistance .rho. (.OMEGA..multidot.cm) of the conveyer belt, and a relative dielectric constant .epsilon. of the conveyer belt are set so as to satisfy relations as follows:
• X/V.ltoreq.(.epsilon..multidot..epsilon..sub.0 .multidot..rho.).times.15
• and
• 5.times.10.sup.8 .ltoreq..rho..ltoreq.10.sup.14.

An image forming apparatus comprising:

• a plurality of image carriers sequentially arranged in parallel with each other;
• a plurality of image forming means for respectively forming developer images on the image carriers;
• supply means for supplying a transfer material onto which the developer images are transferred;
• a conveyer belt provided so as to oppose the image carriers, for conveying the transfer material supplied from the supply means through the image carriers;
• and
• a plurality of transfer means for maintaining the supplied transfer material on the conveyer belt by a suction force and for transferring the developer images formed on the image carriers to the transfer material, the transfer means including a plurality of transfer members provided in contact with the conveyer belt at a number of contact points on a side of the belt opposite to the image carriers, and bias applying means for applying a transfer bias through the transfer members to the transfer material on the conveyer belt;
• wherein a conveying speed V (mm/sec) of the conveyer belt, a distance X (mm) between two adjacent image carriers, a volume resistance .rho. (.OMEGA..multidot.cm) of the conveyer belt, and a relative dielectric constant .epsilon. of the conveyer belt are set so as to satisfy relations as follows:
• X/V.ltoreq.(.epsilon..multidot..epsilon..sub.0 .multidot..rho.).times.20
• and
• 5.times.10.sup.9 .ltoreq..rho..ltoreq.10.sup.15.
• 13.