rubber material such as styrene butadiene rubber butadiene rubber ethylene propylene rubber chloroprene rubber acrylonitrile butadiene rubber fluoropolymer rubber or polyurethan rubber may be used for elastic material layer 45 b a material having a predetermined resistivity may be obtained by adding an electrically conductive material such as carbon black aluminum powder nickel powder or tin oxide powder to one of the aforementioned rubber materials as an alternative an ionic additive or an electrically conductive resin may be added to one of the aforementioned rubber materials however one is not limited to use of one of the aforementioned materials one kind of aforementioned material with additives or a plurality of the aforementioned materials with additives may be mixed and used the thickness and elongation of elastic material layer 45 b is important for controlling formation of transfer nip color drift or scattering of toner therefore elastic material layer 45 b should have a thickness between the range of 100 u03bcm 1000 u03bcm more preferably 300 u03bcm 700 u03bcm and a ratio of an elongation before intermediate transfer belt 45 is communicated with the driving force of driving roller 46 to an elongation after it leaves driving roller 46 is preferably 2 10 if the thickness is less than 100 u03bcm enough transfer nip can not be taken if the thickness is greater than 1000 u03bcm it surpasses a range for use of the belt releasing material layer 45 c communicates softness of elastic material layer 45 b to the surface of photosensitive body drums 41 a 44 a releasing layer 45 c is softer and thinner than the other layers of intermediate transfer belt 45 and is preferably 3 u03bcm 15 u03bcm in thickness the proper releasing effect as well as durability is.