Browse Prior Art Database

Automatic Carriage Re Synchronization

IP.com Disclosure Number: IPCOM000074333D
Original Publication Date: 1971-Apr-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Frassetto, HE: AUTHOR [+2]

Abstract

Present line printers contain various methods for moving the forms past the print mechanism. In past printers, this movement was controlled with a paper tape. On presently planned printers, this control is accomplished with a "tapeless carriage," (form image contained in a loadable buffer in place of tape). In both cases there is presently no method used to re-establish synchronization between the form and the controlling tape or buffer in the event that the two get out of synchronization.

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Automatic Carriage Re Synchronization

Present line printers contain various methods for moving the forms past the print mechanism. In past printers, this movement was controlled with a paper tape. On presently planned printers, this control is accomplished with a "tapeless carriage," (form image contained in a loadable buffer in place of tape). In both cases there is presently no method used to re-establish synchronization between the form and the controlling tape or buffer in the event that the two get out of synchronization.

The following describes a new approach to carriage operations which will allow the printer control unit to automatically re-establish synchronization between the forms and the image in the Control Unit Buffer if the two lose synchronization.

The approach hinges basically on the addition of an emitter 10 designated as the 60 degree emitter, since its pulse will occur every 60 degrees of tractor rotation or 1/2" of forms movement. The microprogram for the carriage control will retain the information which pertains to the relationship between the form and the 60 degree emitter.

In order to initially establish this relationship, the

Control-Unit will position the tractor pins to a predetermined position prior to the loading of new forms. With this relationship established, each following 60 degree emitter pulse will be counted from form perforation (X Bit in Buffer) to the next form perforation.

If the carriage checking hardware/software detects an out-of-sync condition, the accumulated 60 degree data will allow the ca...