US-12623459-B2 - Printing unit with air guides for optimized airflow

US12623459B2US 12623459 B2US12623459 B2US 12623459B2US-12623459-B2

Abstract

A 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. The air guides are positioned at opposite ends of the printhead and include respective guide walls for directing the airflow towards the aerosol extractor.

Inventors

Glenn Horrocks
Samuel Mallinson
Michael Hudson
Joseph Tharion

Assignees

MEMJET TECHNOLOGY LIMITED

Dates

Publication Date: 20260512
Application Date: 20240509

Claims (14)

1 . A printing unit comprising: 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 guide walls extend upstream from the aerosol extractor at least partially along opposite shorter sides of the slot; and a lower surface of the aerosol extractor and a lower surface of the air guides are generally coplanar.
2 . The printing unit of claim 1 , wherein the guide walls extend parallel with the media feed direction.
3 . The printing unit of claim 1 , wherein the guide walls extend upstream of the printhead and the slot.
4 . The printing unit of claim 1 , wherein the aerosol extractor extends into a gap between the base plate and the media feed path.
5 . The printing unit of claim 1 , wherein the aerosol extractor comprises at least one suction nozzle or a suction slit positioned less than 30 mm downstream of the printhead.
6 . The printing unit of claim 1 , wherein the aerosol extractor is at least coextensive with rows of ink ejection nozzles in the printhead.
7 . The printing unit of claim 6 , wherein the guide walls extend along opposite ends of the printhead and partially along a downstream side of the printhead towards side edges of the aerosol extractor.
8 . The printing unit of claim 1 comprises first and second printheads positioned in a staggered overlapping arrangement, wherein: the first and second printheads are positioned in respective first and second slots; the first and second printheads have respective first and second aerosol extractors; the first and second aerosol extractors are positioned at respective downstream edges of the first and second slots; and first and second sets of air guides are positioned at opposite ends of respective first and second printheads.
9 . The printing unit of claim 8 , wherein the first printhead is an upstream printhead and the second printhead is a downstream printhead relative to the media feed direction.
10 . The printing unit of claim 9 , wherein the first printhead is part of a first inkjet module and the second printhead is part of a second inkjet module.
11 . The printing unit of claim 9 , wherein the first and second inkjet modules are mounted on a unit chassis in opposite forward and reverse orientations.
12 . The printing unit of claim 11 , wherein the first aerosol extractor has a different configuration than the second aerosol extractor.
13 . The printing unit of claim 12 , wherein 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.
14 . The printing unit of claim 11 , wherein the first set of air guides has a different configuration than the second set of air guides.

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, of the same title, 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 be suctioned from lateral regions upstream of