Advancing material of indeterminate length – Means to engage longitudinally spaced modifications in material – Pins on flexible belt or chain
Patent
1982-12-06
1984-09-25
Christian, Leonard D.
Advancing material of indeterminate length
Means to engage longitudinally spaced modifications in material
Pins on flexible belt or chain
226 87, G03B 130
Patent
active
044731795
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to a pin feed mechanism for transporting continuous stationery. The invention has particular application to a mechanism for transporting continuous forms paper in high-speed line printers.
High-speed line printers usually function as peripheral devices of electronic data processing systems for printing out information generated by such systems. As information is generated at extremely high speeds, the printers must also be capable of operating at high-speed, and typical line printers used for this purpose are capable of printing about 120 lines per minute.
The stationery used for high-speed printers of this kind is continuous and is usually fed from a roll or from a stack of fan-folded stationery. Typically, continuous forms paper is provided with feed apertures or perforations at both longitudinal edges of the paper to enable feed pins or sprockets of a transport mechanism to engage the apertures and advance the paper past the printing station to perform a "line feed", a "page feed" or a continuous feed, as required by the system program.
The feeding mechanism for transporting the continuous forms paper may contain a pair of feeding devices each including a sprocketed endless tractor belt and a pressure shoe between which the paper passes during the feeding operation, the pins or sprockets of each belt being arranged to engage with a respective series of perforations along a longitudinal edge of the paper. Alternatively, the feeding mechanism may include a drum or cylindrical platen having a series of pins around its periphery at either end. The advantage of the tractor belt arrangement is that the distance between the two feeding devices may be adjusted to accept papers or different widths.
A problem encountered with pin feed mechanisms of the above described types is that the pins penetrating the perforations of the paper tend to cause deformation or even tearing of the paper at the points of contact with the pins at the high rate of paper advance usual with conventional line printers. This may be particularly troublesome with multi-copy forms sets where the perforations are not always properly aligned, and deformation of the bottom forms paper may cause bulging of the set and jamming of the feed mechanism leading to a disruption of the printing operation.
SUMMARY OF THE INVENTION
There is provided, according to the present invention, a pin feed mechanism for transporting continuous stationery having perforations provided at both longitudinal edges thereof, in which transport pins provided on driving means are arranged to engage with the perforations and move the stationery, wherein each pin is so shaped that the paper engaging surface thereof has a substantially constant radius of curvature along the length of the pin.
According to another aspect of the invention, there is provided a transport system for feeding stationery in a printer, including continuous stationery having perforations provided at both longitudinal edges thereof and a pin feed mechanism having transport pins arranged on a driving belt to engage with the perforations and move the stationery, wherein the paper engaging surface of each pin has a substantially constant radius of curvature along the length of the pin, which radius is substantially equal to the radius of curvature of the perforations of the stationery. This is accomplished in the preferred embodiments by providing a tapered end portion on each pin that has the cross-sectional shape of a biconvex lens.
It is, therefore, an object of the present invention to provide an improved feed mechanism for feeding stationery or paper in a line printer.
It is another object of the present invention to provide an improved feed mechanism of the type employing pins for engaging perforations along the longitudinal margins of stationery being fed or advanced by the feed mechanism.
It is a further object of the present invention to provide a pin feed mechanism in which the problems of deformation or tearing of the paper adjacent the perf
REFERENCES:
patent: 2315731 (1943-04-01), Paris
patent: 3015425 (1962-01-01), Wicklund
patent: 3368727 (1968-02-01), Sutton
patent: 4214691 (1980-07-01), Van Namen
IBM Technical Disclosure Bulletin, vol. 20, No. 11A, Apr. 1978, Forms Feed Tractor, C. M. McCray pp. 4524.
Christian Leonard D.
Clark Robert L.
Jewett Stephen F.
NCR Corporation
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