US-12617210-B2 - Printing unit with aerosol extractors for overlapping printheads

US12617210B2US 12617210 B2US12617210 B2US 12617210B2US-12617210-B2

Abstract

A printing unit includes: a unit chassis for mounting over a media feed path; first and second elongate printheads mounted on the unit chassis and positioned in an overlapping arrangement across the media feed path; a first aerosol extractor positioned downstream of the first printhead relative to the media feed direction; and a second aerosol extractor positioned downstream of the second printhead and the first aerosol extractor relative to the media feed direction. The first and second aerosol extractors are positioned at a same distance from their respective first and second printheads.

Inventors

Glenn Horrocks
Samuel Mallinson
Michael Hudson
Joseph Tharion

Assignees

MEMJET TECHNOLOGY LIMITED

Dates

Publication Date: 20260505
Application Date: 20240509

Claims (12)

1 . A printing unit comprising: a unit chassis for mounting over a media feed path; first and second elongate printheads mounted on the unit chassis and positioned in an overlapping arrangement across the media feed path such that the second printhead is downstream of the first printhead relative to a media feed direction; a first aerosol extractor positioned downstream of the first printhead relative to the media feed direction, the first aerosol extractor extending into a gap between the unit chassis and the media feed path and providing an airflow through a first print zone associated with the first printhead; and a second aerosol extractor positioned downstream of the second printhead and the first aerosol extractor relative to the media feed direction, the second aerosol extractor extending into a gap between the unit chassis and the media feed path and providing an airflow through a second print zone associated with the second printhead, wherein: the first and second aerosol extractors are positioned at a same distance from their respective first and second printheads; and the first aerosol extractor is asymmetric in plan view and comprises a manifold arm having a finger portion positioned between the first and second printheads.
2 . The printing unit of claim 1 , wherein each of the first and second aerosol extractors is at least coextensive with the respective first and second print zones of the first and second printheads.
3 . The printing unit of claim 1 , wherein the finger portion has a width of less than 50 mm along the media feed direction.
4 . The printing unit of claim 1 , wherein the first and second aerosol extractors have different configurations.
5 . The printing unit of claim of claim 1 , wherein the first and second aerosol extractors have overlapping portions along the media feed direction.
6 . The printing unit of claim 1 , wherein the first and second aerosol extractors are positioned at a distance of less than 30 mm, along the media feed direction, from the respective first and second printheads.
7 . The printing unit of claim 1 , wherein the first printhead is part of a first inkjet module and the second printhead is part of a second inkjet module.
8 . The printing unit of claim 7 , wherein the first and second inkjet modules are mounted on a unit chassis in opposite forward and reverse orientations.
9 . The printing unit of claim 1 further comprising first and second sets of air guides associated with the respective first and second aerosol extractors, the air guides having guide walls for directing an airflow towards its respective aerosol extractor.
10 . The printing unit of claim 9 , wherein the first set of air guides has guide walls extending upstream of the first aerosol extractor relative to the media feed direction.
11 . The printing unit of claim 9 , wherein the second set of air guides has guide walls extending upstream of the second aerosol extractor relative to the media feed direction.
12 . The printing unit of claim 9 , wherein lower surfaces of the first and second aerosol extractors and lower surfaces of the first and second sets of air guides are generally coplanar.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit or priority to U.S. Provisional Patent Application Ser. No. 63/505,348 filed May 31, 2023, entitled “Printing Unit with Air Guides for Optimized Airflow”, the contents of which being incorporated herein by reference in its entirety. TECHNOLOGICAL FIELD This disclosure relates to a high-speed printing unit. It has been developed primarily for optimizing print quality in a digital inkjet press. BACKGROUND Inkjet printers employing Memjet® pagewide technology are commercially available for a number of different printing applications, including desktop printers, digital inkjet presses and wideformat printers. Memjet® printers typically comprise one or more stationary inkjet printheads having a length of at least 200 mm, which are user-replaceable. For example, a desktop label printer comprises a single user-replaceable full color printhead, a high-speed inkjet press comprises a plurality of user-replaceable monochrome printheads aligned along a media feed direction, and a wideformat printer comprises a plurality of user-replaceable printheads in a staggered overlapping arrangement so as to span across a wideformat media feed path. Analogue printing presses are conventionally used for relatively long print runs where the cost of producing dedicated printing plates is economically feasible. Increasingly, industrial print systems use single-pass digital inkjet printing for relatively shorter print runs. Digital inkjet printing avoids the high set-up costs of producing printing plates and allows each print job to be tailored to a particular customer. Desirably, web feed systems for existing analogue print systems should be adaptable so as to enable ‘drop-in’ inkjet modules in place of, for example, offset printing stations. Memjet® printing technology, which uses rows of print chips butted end-on-end to construct a pagewide printhead, is highly suited for reducing the overall span of the print zone along a media feed direction. Each print chip has either four or five active nozzle rows, which may be used for redundant printing. U.S. Pat. No. 10,857,821 (the contents of which are incorporated herein by reference in its entirety) describes a printing system having a configurable array of print modules, each print module having a respective monochrome printhead configured for single-pass printing. For example, four print modules may be arranged along a media path for full-color (CMYK) printing with 5× redundancy in each color plane. While the system described in U.S. Pat. No. 10,857,821 provides OEMs with flexibility in the design of inkjet presses, as well as high-quality and high-speed printing using 5× redundancy, the print modules must be aligned and spaced along the media feed path for full-color printing. This places demands on media feed systems, which are required to align all colors and, consequently, there are relatively high set-up costs for OEMs. Nevertheless, those costs are still significantly less than alternative pagewide printing systems that use overlapping print chips or very large print chips to achieve single-pass printing. U.S. Pat. No. 10,293,609 (the contents of which are incorporated herein by reference in its entirety) describes a full-color pagewide printhead having two rows of butting print chips receiving ink from a common manifold. The printhead has 2× redundancy for each ink color provided by four active nozzle rows in each row of print chips. U.S. patent application Ser. No. 18/309,412 filed Apr. 28, 2023 (the contents of which are incorporated herein by reference in it entirety) describes a printing unit with a cantilevered aerosol extractor. U.S. Pat. Publication No. 2022/0324239 (the contents of which are incorporated herein by reference in its entirety) describes a printing unit with overlapping upstream and downstream printheads and an aerosol extractor. It would be desirable to provide a low-cost printing unit having optimized aerosol extraction and airflow through the print zone(s), thereby optimizing print quality. SUMMARY In a first aspect, a printing unit is disclosed. In one embodiment, the printing unit includes: a base plate defining an elongate slot extending across a media feed path; an elongate printhead positioned in the slot for printing onto print media fed along the media feed path; an aerosol extractor positioned downstream of the printhead relative to a media feed direction, the aerosol extractor providing an airflow through a print zone associated with the printhead; and air guides projecting from a lower surface of the base plate towards the media feed path, wherein the air guides are positioned at opposite ends of the printhead and comprise respective guide walls for directing the airflow towards the aerosol extractor. The printing unit according to the first aspect advantageously achieves optimal airflow through the print zone of the printhead. By minimizing the extent to which air may