Device for driving documents guided by one edge on a reference plane

A device for driving documents having one edge in contact with a reference plane includes a drive roller having its axis perpendicular to the reference plane, and an idle roller pressing a drive document against the drive roller. The axis of the idle roller can be freely tilted in a plane parallel to the plane of the driven document, between two limit positions on either side of a position perpendicular to the reference plane. A spring urges the idle roller against an abutment at one end of its axis to create friction.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to devices for driving documents, such as 
checks, perpendicularly in contact with a reference plane, during a 
process, such as printing or reading magnetic or optic information. 
2. Discussion of the Related Art 
FIG. 1 is a perspective view of a conventional device for processing 
documents. The device includes a frame 10 on which is mounted a driving 
device formed by a pair of rollers 72 and 14 in contact with each other 
and having parallel axes. One of the rollers, drive roller 12, is 
generally of a material having a high adherence to the documents. The 
drive roller is rotated by a motor (not shown). The other roller, idle 
roller 14, freely rotates about its axis. The frame 10 includes a 
reference plane 10-1 to which the roller axes are perpendicular and 
against which should be urged the lower edge of a document 16 driven by 
the device. In practice, this reference plane is the bottom of a groove 
10-2 for guiding the document 16. 
The documents to be driven arrive, inserted by hand or by another driving 
device, between the two rollers and are then dragged by adherence to the 
drive roller 12. The idle roller 14 provides sufficient pressure of the 
documents against the drive roller so that they are dragged. 
In systems which process the documents, such as for printing or reading 
magnetic or optic information, the documents should have one of their 
edges in contact with a reference plane, which provides a reference for 
processing the documents. A processing device, designated 17, is 
represented in FIG. 1. 
A first solution to ensure the contact with a reference plane is to provide 
the documents already in contact with the reference plane to the driving 
device and to construct the rollers (idle or drive roller) with an axis as 
perpendicular as possible to the reference plane 10-1. This solution 
requires a manufacturing accuracy that is particularly expensive. 
Another solution is to tilt the axis of one of the rollers, generally the 
idle roller, in a plane parallel to the plane of the driven document 16. 
With such a solution, when the drive roller rotates in the "right" 
direction, the inclination of the idle roller urges the document towards 
the reference plane as it is driven. To limit the pressure applied to the 
document 16 once the latter is in contact with the reference plane 10-1, 
the idle roller is generally of a material having a low adherence. In 
contrast, if the drive roller rotates in the wrong direction, the driven 
documents are separated from the reference plane. 
Thus, such a driving device which is inexpensive to manufacture is a 
unidirectional device. 
European patent application 193,258 describes a device for driving 
documents having one edge in contact with a reference plane. The driving 
device includes a drive roller having its axis perpendicular to the 
reference plane and an idle roller pressing a driven document against the 
drive roller. The axis of the idle roller is freely tiltable in a plane 
parallel to the plane of the document, between two limit positions on 
either side of a position perpendicular to the reference plane. 
A minimum resistance to rotation is provided between the idle roller and 
its axis, but the idle roller should be tiltable as freely as possible. 
To reduce the resistance to tilting, the support of the idle roller is 
mounted to the frame through a ball-bearing. This mounting solution is 
particularly expensive and difficult to carry out, because the 
ball-bearing, which is very small, must be mounted with a high axial 
accuracy in order to ensure that the idle roller exerts sufficient 
pressure on the drive roller. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a tiltable idle roller 
document driving device, in which the configuration allowing the tilting 
of the idle roller is inexpensive and easy to mount. 
According to the invention, the configuration of the idle roller support 
includes, at the most distant side from the drive roller, an elastically 
urged piston ended by a tip penetrating in a female cone of the frame. 
According an embodiment of the invention, the configuration includes, at 
the side nearest to the drive roller, a finger penetrating in a groove of 
the frame that is parallel to the axis of the drive roller, and stopped by 
one end of the groove. 
According to an embodiment of the invention, the support has an extension 
cooperating with a portion of the frame to limit the inclination of the 
idle roller. 
According to an embodiment of the invention, the friction means include a 
spring urging the idle roller against an abutment of the axis of the idle 
roller. 
The foregoing and other objects, features, aspects and advantages of the 
invention will become apparent from the following detailed description of 
the present invention when taken in conjunction with the accompanying 
drawings.

DETAILED DESCRIPTION 
FIGS. 2A and 2B represent the same elements as those in FIG. 1, designated 
with the same reference numerals. A drive roller 12 and an idle roller 14 
are mounted on a frame 10. Roller 12 has an axis 12-1 guided in a bearing 
of frame 10, which allows to rotate roller 12, for example, with a motor 
(not shown) located in the lower part of the frame. 
Frame 10 includes a reference plane 10-1 to which axis 12-1 of roller 12 is 
perpendicular and toward which the lower edge of a document 16, driven by 
the device, has to be urged. Like the device of FIG. 1, this reference 
plane is at the bottom of a groove 10-2 for guiding document 16. 
The idle roller 14 rotates about an axis 18 integral with a support 20, in 
turn mounted on frame 10 along an axis A which is perpendicular to the 
plane of document 16, and crosses axis 12-1 of the drive roller. Support 
20 is slidably mounted along axis A. A spring 22, compressed between 
support 20 and a wall of frame 10, maintains the idle roller 14 in contact 
with the drive roller 12. Thus, the document 16 is maintained in contact 
with the drive roller 12 which drags the document by friction. 
The support 20 imparts to axis 18 of the idle roller 14 a free inclination 
in a plane parallel to the plane of document 16, to both sides of a 
position PO parallel to axis 12-1 of the drive roller. The inclination of 
axis 18 is limited between two limit positions P1 and P2 on both sides of 
position PO by a double abutment. This double abutment includes, for 
example, an extension 20-1 of support 20 ending at its distal extremity by 
a fork 20-2 parallel to the plane of document 16 and overlapping a flat 
extension 10-3 of the frame. 
With this configuration, provided there is a determined rotation resistance 
of the idle roller 14 about its axis 18, the axis of the idle roller 14 
reaches its limit position P1 or its limit position P2 depending upon the 
rotation direction of the drive roller 12. As represented, if the drive 
roller 12 rotates in a direction R1, the idle roller 14 rotates in an 
opposite direction -R1 and reaches its limit position P1. If the drive 
roller 12 rotates in an opposite direction, as represented by a dotted 
arrow R2, the idle roller 14 tilts in the opposite direction and reaches 
its limit position P2. Accordingly, whatever the rotation direction of the 
drive roller 12, that is, whatever the driving direction of documents 16, 
the idle roller tilts in a direction where it always urges the lower edge 
of document 16 against the reference plane 10-1. 
The end positions P1 and P2 correspond to inclinations of only a few 
degrees with respect to position PO. The idle roller is of a low friction 
material, so that the force applied to document 16 does not crumple it. 
It is important, in order to obtain a good operation of the device, that 
the friction between the idle roller 14 and its axis 18 is sufficient to 
overcome the resistance to tilting about axis A, by applying a tangential 
force on roller 14. Indeed, the rotation of the drive roller 12 cannot 
otherwise tilt roller 14. 
In an embodiment, to provide sufficient friction of substantially constant 
value over time, roller 14 is slidably mounted on its axis 18, and a 
spring 24 is compressed between support 20 and the lower surface of roller 
14 and urges the upper surface of roller 14 towards an abutment of axis 
18, such as a shoulder or an elastic ring 18-1. A ring 26 is placed 
between spring 24 and roller 14. 
Additionally, it is desirable to reduce the resistance to tilting about 
axis A so that it does not unduly increase the friction necessary in 
consequence between roller 14 and its axis 18. A too high friction between 
roller 14 and axis 18 would require to increase the size of the motor of 
roller 12, which has to overcome this friction. FIG. 3 represents an 
embodiment of a low friction configuration according to the invention. 
Support 20 includes, at the most distant side from the drive roller 12, a 
cylindric extension 20-2 covered by a piston 28. The piston 28 ends with a 
male cone placed in a female cone of frame 10. A spring 30 is compressed 
between the end of extension 20-2 and the top of piston 28 to urge the 
idle roller 14 against the drive roller 12 and to hold the configuration 
together. 
Support 20 includes, at the side nearest to the drive roller 12, a finger 
20-3 along axis A which penetrates in a vertical groove 10-4 of frame 10. 
The groove 10-4 is perpendicular to the plane of document 16. Finger 20-3 
comes into abutment against the upper end of groove 10-4. 
This configuration is very easy to mount and has a particularly low 
friction. 
Having thus described one particular embodiment of the invention, various 
alterations, modifications, and improvements will readily occur to those 
skilled in the art. Such alterations, modifications, and improvements are 
intended to be part of this disclosure, and are intended to be within the 
spirit and scope of the invention. Accordingly, the foregoing description 
is by way of example only and is not intended as limiting. The invention 
is limited only as defined in the following claims and the equivalents 
thereto. In particular, other arrangements than those described can be 
provided to obtain sufficient friction between the idle roller and its 
axis and to obtain the limit inclination positions of the idle roller.