The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 26, 1988
Filed:
Feb. 24, 1987
Kieran B Kelly, Vancouver, WA (US);
William R Huseby, Vancouver, WA (US);
Robert P Callaway, Vancouver, WA (US);
Chris A Rasmussen, Vancouver, WA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
Method and apparatus are provided for moving perforated continuous paper (10) through a dual axis printer (12), with both axes (14, 30) driven, while regulating the feed with the perforations and maintaining a controlled tension (38a) in the paper between the two driven axes. The novel approach in this invention is the addition of a set of spring-loaded friction surfaces (56a-62a), incorporated into a gear transmission (50), which limit the amount of torque which can be transmitted to the unregulated drive axis, with the direct effect of controlling the tension in the paper between the two axes. In order to create this tension, the unregulated axis is driven at a slightly greater speed than the regulated axis (with speed measured in terms of inches of paper per revolution of the driven gear (20)). In normal operation, the slack in the paper is taken up, to the point at which the tension is at the correct level, and then enough slip occurs at the friction surfaces to drive the same amount of paper at both the regulated drive (16) and unregulated drive (32). The unregulated drive is only overdriven slightly (e.g., about 0.2%) to allow accurate feeding of single sheets (which are not driven by the regulated drive). This slight overdrive requires only minimal slip at the friction surfaces when driving continuous paper and thus keeps the amount of wear small.