US 2003/0147678 A1 · Image forming apparatus

Abstract

An image forming unit 41-44 are disposed along a primary transfer part. A transporting pathway of the primary transfer part is inclined upwardly in the direction from the image forming unit 41 to the image forming unit 44. An intermediate transfer belt is driven by a driving roller 46 and applied with a tension by a supporting roller 47. A backup roller 48 opposes a transfer roller. An intermediate transfer belt unit is composed of the intermediate transfer belt, the driving roller, the supporting roller and the backup roller. A primary transfer part is defined between the driving roller and the supporting roller. The backup roller is disposed vertically under the image forming unit 41 whereby the image forming apparatus becomes compact and a recording medium can be easily separated from the intermediate transfer belt.

Claims25

Dependent claims

In an image forming apparatus having a plurality of image forming units each of which forms a toner image by developing an electrostatic latent image on an image bearing body provided in correspondence to each color and an intermediate transfer body which is transported along a predetermined transport pathway and to which the toner image is transferred in a primary transfer part as a primary transfer image wherein the image forming units is disposed along a primary transfer part and an image is formed by secondarily transferring the primary transferred image to a recording medium with secondary transfer roller at a secondary transferring position which exists downstream side of the primary transfer part, the image forming apparatus is characterized in that the transporting pathway of the primary transfer part is inclined upwardly in the direction from an image forming unit disposed at the most upstream point to an image forming unit disposed at the most downstream point, the primary transfer part further comprising a first roller which transports the intermediate transfer body, a second roller which gives a tension to the intermediate transfer body and a third roller which confronts the second roller at secondary transfer position, the intermediate transfer body unit comprising the intermediate transfer body, the first roller, the second roller and the third roller where the primary transfer part is defined between the first roller and the second roller.

An image forming apparatus comprising:

an image bearing body which forms an image by an electro-photographic method;
an intermediate transfer belt which is rotated by a driving roller and transfers primarily the image on the image bearing body;
and
a mechanism for secondarily transferring the image on the intermediate transfer belt to a final transfer member,
wherein the intermediate transfer belt has a plurality of elastic layers and when a percentage difference of a stretched length of an outer circumference of the intermediate transfer belt to an inner circumference thereof at a position of contact to the driving roller is A% and a percent difference of a length of stretched side of the belt driven and stretched by the driving roller to a length of non-stretched opposite side of the belt is B%, the intermediate transfer belt is configured so that ranges of A and A+B fall simultaneously into inequalities of 3<A<7 and 3<A+B<10.

2 more elements

Dependencies are inferred from the claim text.

Image forming apparatus

Life of this patent

Image forming apparatus

Life of this patent

Abstract

Claims25