Inkjet printers employing Memjet® technology are commercially available for a number of different printing formats, including small-office-home-office (“SOHO”) printers, label printers and wideformat printers. Memjet® printers typically comprise one or more stationary inkjet printhead cartridges, which are user-replaceable. For example, a SOHO printer comprises a single user-replaceable multi-colored printhead cartridge, a high-speed label printer comprises a plurality of user-replaceable monochrome printhead cartridges aligned along a media feed direction, and a wideformat printer comprises a plurality of user-replaceable printhead cartridges in a staggered overlapping arrangement so as to span across a wideformat pagewidth.
For commercial web-based printing, different customers have different printing requirements (e.g. print widths, print speed, number of ink colors). It is, therefore, desirable to provide customers with the flexibility to design a printing system that suits their particular needs. A commercial pagewide printing system may be considered as an N×M two-dimensional array of printheads having N overlapping printheads across the media path and M aligned printheads along the media feed direction. Providing customers with the flexibility to select the dimensions and number of printheads in an N×M array in a modular, cost-effective design would provide access to a wider range of commercial digital printing markets that are traditionally served by offset printing systems.
However, web-based printers having multiple inkjet printheads present many design challenges. For printhead maintenance, it is desirable not to break the web of media during maintenance interventions. Typically, this requires lifting the printheads away from the web and sliding a maintenance chassis underneath the printheads so that a maintenance operation (e.g. wiping or capping) can be performed (see, for example, U.S. Pat. No. 8,616,678 the contents of which are incorporated herein by reference). Moreover, curved media feed paths are preferable for controlling web tension in web-based printing with printheads arranged radially around the media path. A modular and scalable web-based printing system must address the design challenges of maintaining each printhead in the array.
Staggered overlapping arrangements of stationary printheads across the width of a media feed path require minimizing the length of the print zone in the media feed direction in order to minimize print artifacts from overlapping printheads. The competing requirements of maintaining each printhead and minimizing the length of the print zone necessitate compact maintenance arrangements.
Inkjet printheads have a finite lifetime and require regular replacement in a web-based printer. It is desirable to simplify the replacement of printheads in order to minimize downtime in a digital press.
For scalability, it is desirable for each printhead to be replaceably housed in a self-contained module, which supplies ink, power and data to the printhead. Each module should be as compact as possible so that the modules can be stacked in an overlapping arrangement without affecting the length of the print zone in the media feed direction. Moreover, heat-generating electronic components need to be cooled and protected from ink mist.