and the shoe 22 the blanket moves at a velocity matching that of the roll 24 with which it is in contact the blanket 30 is a flexible sheet and can easily be bent without deformation in a single plane stated another way a flexible sheet can easily be bent in the shape of a conic section or a series of conic sections such shapes are also known as developable surfaces the shape of the blanket 30 as it moves through the nip is somewhat cardioid in shape and this shape is developable the cylindrical ends 36 40 of the blanket 30 are clamped by toroidal bladders 57 to the heads 38 42 however the transition between the cardioid shape and the clamped cylindrical ends 36 40 of the blanket 30 causes bending in two planes simultaneously these areas or regions 58 59 of biplanar bending are subject to considerable deformation which results in a concentrated region of blanket fatigue there are two highly fatigued areas on either side of the nip 56 a front region 58 and a back region 59 the regions 58 59 are the portions of the blanket 30 in which blanket failure originates at the same time the blanket 30 is being fatigued it is also being subjected to squeezing as it passes through the nip 56 this squeezing or compression causes the blanket to grow in machine direction length for the blanket 30 to function it must be kept under tension in the machine direction the tension of the blanket 30 is accomplished by inflating the blanket.