Duplex printing apparatus

Abstract

Designed to efficiently effect duplex printing with a single digital printer, a duplex printing apparatus is provided which comprises: a pair of feed roll units arranged across the digital printer from each other in a direction of travel of a web of paper and each adapted to be driven synchronously with a paper supply and a paper takeup unit and for feeding the web of paper to travel forwards and backwards while an upper surface of the web of paper faces an under surface of the digital printer; a turnover unit arranged at one of a site between the paper supply unit and the feed roll unit on the paper supply side and a site between the paper takeup unit and the feed roll unit on the paper takeup side, whereby the traveling web of paper is turned over through, and is allowed to by-pass, a turnover path of the turnover unit; a mark sensor arranged on at least one of sides across the-digital printer from each other in a direction of travel of the web of paper and upstream in a direction of travel of the web of paper, an upper surface of which is being printed on by the digital printer, for detecting a timing mark which has been printed by the digital printer on an under surface of the web of paper; and a control unit operable in response to a detection value from the mark sensor for controlling the digital printer so that on the upper surface of the web of paper there is printed an image corresponding to an image that has been printed on the under surface of the web of paper.

Description

technical field [0001] The invention relates to a double-sided printing device, which is used for printing on the front and back of roll paper by digital printing machines such as inkjet printers and electrophotographic printing machines. Background technique [0002] In the past, as a device for printing on both sides of a roll paper with a digital printing machine, some use two digital printing machines. The front and back of the web are reversed, and the back of the web is printed by the second digital printing machine (refer to Japanese Patent Application Publication No. 2010-99955), or, as shown in Japanese Patent Application Publication No. 2005-335145, some use A digital printing machine, after the web is moved to the digital printing machine and the front side of the web is printed, the front and back of the web are turned over, and the web is moved to the digital counter again and Printing is done on the reverse side of the printing web. [0003] The former of the...

AI Technical Summary

Problems solved by technology

[0003] The problem with the former in the above-mentioned conventional example is that two expensive digital printing machines for the front and the back are required, and the equipment cost becomes expensive and the device becomes large

[0005] Therefore, for the latter in the conventional example, when performing double-sided printing with a device with a single-sided printing specification, there is a conveying operation for resetting the roll paper after printing on one side, and a rewinding machine for rewinding. The work burden such as transporting the roll paper increases, and the installation and removal of the roll paper handles heavy objects, so there is a problem of increasing the equipment and work load in order to ensure its safety.

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