Device for conveying sheets

Abstract

A device for conveying sheets through a printing machine which ensures the safe transport of the sheet exactly in the prescribed transport path, at a low material expense. The device for conveying sheets through a printing machine is provided with continuous conveyor belts running over deflection rollers, between which the sheets are held by frictional forces and guided one after the other, whereby to generate the frictional forces, rollers are provided which press the conveyor belts against each other along the conveyance path. The contact surfaces of the conveyor belts with the sheet have a surface coating made of a material with a high coefficient of friction relative to the material of the sheet.

What is claimed is:  
     
         1 . Device for conveying sheets ( 5 ) through a printing machine, consisting of continuous conveyor belts ( 10 ,  15 ) running over deflection rollers ( 35 ), between which the sheets ( 5 ) are held by frictional forces and guided one after the other, whereby to generate the frictional forces, rollers ( 30 ) are provided which press the conveyor belts ( 10 ,  15 ) against each other along the conveyance path, characterized in that the contact surfaces of the conveyor belts ( 10 ,  15 ) with the sheet ( 5 ) have a surface coating ( 20 ) made of a material with a high coefficient of friction relative to the material of the sheet ( 5 ).  
     
     
         2 . Device according to  claim 1 , characterized in that the surface coating ( 20 ) is made out of silicone.  
     
     
         3 . Device according to  claim 1 , characterized in that the material of the surface coating ( 20 ) has a high extensibility.  
     
     
         4 . Device according to  claim 1 , characterized in that to clean the contact surfaces, at least one cleaning device is allocated to the conveyor belts ( 10 ,  15 ).  
     
     
         5 . Device according to  claim 4 , characterized in that as a cleaning device, set cleaning rollers ( 40 ) are provided on the conveyor belts ( 10 ,  15 ).  
     
     
         6 . Device according to  claim 4 , characterized in that at least one roller ( 30 ,  35 ) is provided as a cleaning roller.  
     
     
         7 . Device according to  claim 1 , characterized in that at least the surface coating ( 20 ) of the contact surfaces has an anti-soiling surface.  
     
     
         8 . Device according to  claim 1 , characterized in that the sheet ( 5 ) is held and guided in the center in the conveyance direction, whereby to support the edges overhanging out of the conveyor belts ( 10 ,  15 ), guide elements are provided, on which the sheet ( 5 ) lies during the horizontal conveyance.  
     
     
         9 . Device according to  claim 8 , characterized in that as guide elements, plates, sliding rails or traveling belts are provided.  
     
     
         10 . Device according to  claim 1 , characterized in that the rollers ( 30 ,  35 ) are each set alternatingly along the conveyance path on the side of the conveyor belts ( 10 ,  15 ) that faces away from the contact surface.  
     
     
         11 . Device according to  claim 1 , characterized in that during the horizontal conveyance of sheets ( 5 ), several modules are provided with conveyor belt pairs, whereby each module of the conveyor belt ( 10 ) lying above is constructed shorter than the conveyor belt ( 15 ) lying below, whereby the number of the rollers allocated to the upper conveyor belt ( 10 ) is reduced by one relative to the number of the rollers allocated to the conveyor belt ( 15 ) lying below, and whereby the deflection rollers ( 35 ) of the conveyor belt ( 10 ) lying above act as tension rollers and each are arranged between the deflection rollers ( 35 ) of the conveyor belt ( 15 ) lying below and the roller ( 30 ) adjacent to the deflection roller ( 35 ) of the conveyor belt ( 15 ) lying below.  
     
     
         12 . Device according to  claim 1 , characterized in that the surface coating ( 20 ) is constructed in partial areas of the contact surface.  
     
     
         13 . Device according to  claim 10 , characterized in that the surface coating ( 20 ) is constructed in the form of strips or in the form of separate islands.