High precision roller conveyor

1. A roller conveyor, comprising:

a plurality of rollers ( 2 ) which are consecutive one after the other without intermediate rollers, each of said plurality of rollers ( 2 ) having a cylindrical external surface ( 21 ), arranged to enable the resting of an object to be transported, which is tangential to a transport plane (a) on which the objects are transported;

a motor ( 3 );

a transmission element ( 4 ), which kinematically connects the motor ( 3 ) to the rollers ( 2 );

characterised in that, for each of said plurality of rollers ( 2 ), the transmission element ( 4 ) is placed in contact with (A) portion of the external surface ( 21 ) or (B) a portion of the roller that has the same diameter as the external surface ( 21 ), tangential to the transport plane (a);

wherein the transmission element ( 4 ) comprises a flat belt; wherein the plurality of rollers ( 2 ) comprises a first roller and a last roller; wherein the transmission element ( 4 ) follows ( 1 ) an advancement path where it advances from a beginning location adjacent the first roller and ( 2 ) a return path where it returns to the beginning location; wherein the transmission element ( 4 ), in operation, drives the last roller at an end of its advancement path and then commences its return path without driving another of said plurality of rollers ( 2 ), the last roller being driven only by the transmission element ( 4 ); wherein, when the transmission element ( 4 ) advances along the advancement path, it drives every roller with respect to which it crosses through the vertical plane defined by the rotational axis of said roller; wherein, with respect to the contacting portion of the transmission element ( 4 ) which is in contact with (A) the external surface ( 21 ) or (B) the portion of the roller that has the same diameter as the external surface ( 21 ), such contacting portion of the transmission element ( 4 ) is free from contact on its surface which is opposite its surface in contact with (A) the external surface ( 21 ) or (B) the portion of the roller that has the same diameter as the external surface ( 21 ).

2. The conveyor according to claim 1 , comprising a plurality of tensioning rollers ( 5 ), placed in contact with the transmission element ( 4 ), on the opposite side of the transmission element ( 4 ) with respect to the rollers ( 2 ), so as to press the transmission element ( 4 ) into contact with the external surface ( 21 ) or the portion of the roller that has the same diameter as the external surface ( 21 ).

3. A machine for digital printing of slabs of glass or other materials, comprising a printing head and a transport line for the slabs, arranged to carry the slabs to below the printing head, characterised in that the transport line comprises a roller conveyor ( 1 ) according to claim 1 .

4. A method for transporting a slab of glass or other material, comprising the following steps:

to enable support of an object to be transported;

providing a roller conveyor according to claim 1 ;

activating the rollers ( 2 ) in rotation by means of the motor ( 3 ) and the transmission element ( 4 );

arranging the slab on the rollers ( 2 );

transporting the slab on the roller conveyor.

5. The method according to claim 4 , wherein the slab which is transported on the roller conveyor is a slab of glass.