New compact thermal printhead developed for mobile printers

ROHM has created a new thermal printhead – KA2008-B07N70A – compatible with a 2-cell Li-ion battery (7.2V). It is designed to deliver high print quality with low power consumption. On top of that, it is optimised for A4-size printers (210mm in width). Height has been decreased by approximately 16% from the conventional 14mm to a best-in-class 11.67mm – contributing to a more compact printer design. Moreover, optimising the heating element structure while improving the driver IC and wiring layout allows the support for 7.2V operation – decreasing the applied energy needed for printing by approximately 66% compared to a conventional 12V drive (at 50mm/s print speed). Adjustments to the individual wiring of the resistive elements ensure uniform heat generation, stabilising print quality and allowing sharp and high-resolution 203dpi printing – even at speeds up to 100 mm/s.

In recent years, the thermal printer market has been growing in response to expanding demand to print qualified invoices and customs labels fueled by the growth of overseas e-commerce and prescriptions and drug information sheets in hospitals and pharmacies. The demand for mobile printers has surged, particularly in the logistics and business sectors, where portability and ease of maintenance are highly valued. Among these trends, adopting A4-sized thermal printers has been growing in Asian markets, particularly in China, driving the need for 8" thermal printheads.

A4-sized mobile printers face challenges such as high power consumption due to their wider print width and needing larger battery capacities compared to smaller printers such as receipt printers. Moreover, the necessity for multiple driver ICs to control the heating elements in A4-sized printers often results in variations in heat generation due to the differences in wiring lengths between elements, which affect print quality, such as colour development and uniformity.

The device meets these challenges through an optimised design that improves mechanical strength and durability by mitigating the effects of expansion and contraction induced by temperature changes. This meets the stringent durability needs of A4-sized printers (the primary target market) while supporting thermal and transfer printing methods – offering versatile printing for various applications.

While thermal printheads are typically used with connectors and a heat sink, the KA2008-B07N70A can also be supplied as a standalone board, allowing printer manufacturers greater design flexibility.