Recording web drive with rotating pressure pad

A paper drive system for a fiber optic cathode ray tube based recorder in which a rotating compliant foam pressure pad maintains the paper in intimate contact with the fiber optic faceplate. The paper web from a paper supply is gripped between a tire on the rotating pressure pad and a drive roller before passing the faceplate, and thereafter is gripped between the tire on the pressure pad and an idler roller.

BACKGROUND OF THE INVENTION 
The invention disclosed herein relates generally to apparatus for moving 
web type recording media past a recording region, and more particularly to 
a precision paper drive with a rotating pressure pad for use in hard copy 
recording apparatus. 
Hard copy recording apparatus employing a cathode ray tube (CRT) with a 
fiber optic faceplate for supplying luminous signals and a light sensitive 
paper web moving past the faceplate is well known. In such apparatus, the 
fiber optic faceplate is of elongated form and produces luminous signals 
in the form of minute dots in a linear recording region whose length is 
the width of the desired record. It is necessary to maintain the recording 
paper in intimate contact with the recording region of the fiber optic 
face plate to assure accurately recorded signals. Intimate contact is 
necessary to properly focus the luminous dots on the paper. Since the 
depth of field of such an arrangement is in the order of 0.002 inches, the 
recorded dots become noticeably fuzzy with even small gaps between the 
paper and the faceplate. 
In order to obtain an accurate record, it is also necessary to uniformly 
and precisely move the paper past the recording region. This, among other 
things, requires an accurate and precisely controlled drive roller and no 
slippage between the paper and the drive roller. Thus, it is normal to 
press the paper against the drive roller with a relatively hard tire. 
Conventional paper drive systems in recording apparatus of the above 
described type have used a stationary foam pressure pad to hold the paper 
in intimate contact with the faceplate, and a single drive roller/pinch 
roller pair above the faceplate to pull the paper across the recording 
region. The geometry of such drive systems necessitates a relatively large 
border between the end of a paper segment and the beginning of a recorded 
area. 
A large border is undesirable both because it does not fully utilize the 
light sensitive paper which, in the case of paper capable of producing 
color images, is relatively expensive, and because a large boarder may not 
be aesthetically pleasing. Thus, with a conventional paper drive system, 
if a smaller border is desired, extra trimming steps are necessary. 
The applicant has devised a paper drive system which provides for borders 
of any desired width, thereby avoiding disadvantages of prior art paper 
drive systems. This paper drive system also insures an accurate record by 
isolating the paper in contact with the faceplate from fluctuations in 
paper tension on both the supply and output sides of the recording region. 
SUMMARY OF THE INVENTION 
The present invention is a drive system for a recording web, the drive 
system including a circular cylindrical pressure pad extending along its 
axis of symmetry, and having along its length at least two sections of 
compliant foam surface separated by a hard tire whose diameter is slightly 
smaller than the outer diameter of the foam surface. The pressure pad is 
mounted for rotation about its axis of symmetry, and first and second 
rollers rotatable about first and second axes parallel with the axis of 
symmetry are located at circumferentially spaced locations about the axis 
of symmetry. The first and second rollers are positioned with respect to 
the pressure pad so as to grip the recording web between the rollers and 
the tire on the pressure pad. Drive means may be provided for directly 
driving one of the rollers so as to move the web through the system. An 
elongated faceplate having a recording region at which is produced 
luminous signals to be recorded may be located between the first and 
second rollers and in contact with the compliant foam surface on the 
pressure pad for maintaining the recording web in intimate contact with 
the faceplate.