and the work roller which rotates in the direction of arrow 5 the carding process takes place the fiber material is not shown the fiber material which is removed by the work roller from the main cylinder is fed back to the main cylinder by means of the clearing roller which rotates in the direction of arrow 6 the mode of operation of the main cylinder with its pairs of work and clearing rollers is known in principle and since it is already known in the art need not be explained in detail the embodiment illustrated in fig2 differs from that of fig1 in that the work roller rotates in a direction shown by arrow 15 opposite to the direction of rotation of the main cylinder in the embodiment of fig3 the clearing roller is disposed behind the work roller when looking in the direction of rotation of the main cylinder otherwise the directions of rotation are the same as in the normal arrangement of fig1 according to the process of the present invention the sum of the peripheral speeds of the work roller and the clearing roller of one pair of work and clearing rollers in all three of the arrangements shown in fig1 to 3 is greater than 250 m min it is particularly advantageous for the peripheral speed of the clearing roller to be greater than 200 m min and or the peripheral speed of the work roller to be greater than 90 m min according to the embodiment of fig4 the roller card unit is provided with two separate driving motors namely the main driving motor 7 and the driving motor 8 the driving shaft 7 39 of motor.