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:
Mar. 06, 2007
Filed:
Apr. 26, 2005
Ching Keong Tham, Singapore, SG;
Xiaoxi Huang, Singapore, SG;
Ching Keong Tham, Singapore, SG;
Xiaoxi Huang, Singapore, SG;
Hewlett-Packard Development Company, L.P., Houston, TX (US);
Abstract
An apparatus and a method for duplex printing are disclosed. The apparatus includes a print zone where printing is performed and a duplex module configured to change the orientation of the media sheet. The duplex module is positioned so as to receive the media sheet from the print zone, trailing edge first. The method includes feeding a media sheet to the print zone and printing swaths of ink dots on a first side of the media sheet. Black ink density is calculated for each swath containing black ink dots. The highest black ink density is then determined. The media sheet is stopped from advancing after the last swath has been printed on the first side. The first side is allowed to dry for a drying period, which is based on the highest black ink density. After the drying period has elapsed, the media sheet is moved in the reverse direction from the print zone to the duplex module to change the orientation of the media sheet to an orientation suitable for printing on a second side. If the trailing edge of the media sheet is at a position that cannot enter the duplex module after the last swath has been printed on the first side, the media sheet is moved in the forward direction for a minimum distance to enable the trailing edge to enter the duplex module. The media sheet is then re-introduced into the print zone for printing on the second side.