Memjet Printhead

Memjet 8.77 inch / 222.7mm (A4) Printhead

Unique Design, Unique Value

The Memjet printhead technology is uniquely designed to simultaneously achieve high speed color printing at low costs. The Memjet printhead spans the width of a page, requires minimal warm-up time and prints an entire page in one pass. While dramatically improving performance, this fixed-head architecture also reduces the noise, vibration, mechanical complexity and drop-firing complexity associated with traditional inkjet architectures. Memjet printheads are designed as a long-life, customer-replaceable component, allowing customers to keep their printers running at peak performance year after year while protecting their investment. For maximum scalability, the size of the printhead enables a range of wide format applications from a variety of different sized printers.  Each A4 printhead packs 70,400 nozzles into a silicon structure that delivers 1,600 dpi native print quality and is more dense and cost-efficient than other leading inkjet IC designs. Finally, Memjet printheads are the most energy-efficient means of printing a color page on a label printing device. Put it all together and Memjet printheads represent a clear departure from existing inkjet and laser architectures and a offer compelling choice for wide format printing and imaging customers.

View Fixed Printhead vs. Traditional Scanning

Speed, Quality, Cost

The speed of a Memjet system is achieved through the integration and optimization of software and firmware as well as printhead technology. With 70,400 nozzles a typical A4 Memjet printhead is capable of continuously firing up to 900 million drops per second, the time it takes to print an entire A4 page. At 12 inches (305mm) per second, the printhead produces 1600 x 800 dpi quality, the normal print quality needed to produce typical technical documents. At 6 inches (152mm) per second, the printhead produces 1600 x 1600 output and is capable of photo quality graphics. Speed and quality can be achieved simultaneously because there are enough tightly packed nozzles, firing with adequate speed, to achieve sufficient coverage and quality with one pass of the paper. Because the printhead is fixed, ink drop placement is also extremely accurate.

The printhead’s small print path (0.72mm x 222.8 mm) uses significantly less silicon than competing page-wide technologies. Less silicon results in lower cost components and lower cost devices. The printhead also lowers device costs by eliminating the need for complex paper handling. Because the distance across the print path is small and all four colors are put onto the page quickly, there is no need for complex paper handling and/or specialized drop-firing adjustments, needed in some systems to compensate for ink/paper interactions between color planes. The printhead’s integrated paper guide keeps paper traveling underneath the printhead at a fixed distance, further simplifying paper handling related to the print engine.

Memjet Nozzle Structure and Chip Boundary

Flexible Color Configuration

Memjet printhead IC chips contain 5 ink channels and two rows of nozzles per channel. Each individual nozzle structure is 31.7 microns across, enabling 800 dpi, with the second row of nozzles for each color slightly offset from the first enabling 1600 dpi in combination. While the five ink channels can be flexibly configured, the standard configuration for wide format devices is Cyan, Magenta, Yellow and two black ink channels (CMYKK). Other potential configurations include a three color photo system with two Cyan, two Magenta and one Yellow or an all black system with 5 black channels.

Filling the Gaps

The Memjet printhead contains 11 IC chips (20 mm each) placed side by side across the printhead with an approximately 1 micron gap between the IC chips. In order to avoid print quality issues at the gap between chips, Memjet has a uniquely patented “drop triangle” element at the right edge of each chip. The nozzles in the triangle element are timed to fire as if they are sitting with the rows of nozzles above them, avoiding any missing nozzles across the seam between IC chips.

Watch how the chips print at the gap

Memjet Nozzles

Down to the Micron

The nozzles on the Memjet printhead can fire drop sizes from 1-2 picoliters. The initial A4 printhead is tuned to fire 1.4 picoliter drops resulting in an estimated 14 micron drop diameter, a fraction of the size of a human hair.

Self Cooling Design

While there are a number of potential Memjet nozzle designs, initial Memjet nozzle stuctures are uniquely formulated with the heating element in the middle of the ink chamber. This “suspended heater” design allows drops to be ejected using only 170 nanojoules of energy. As drops are ejected, new cooler ink flows into the chamber surrounding and cooling the heating element. The result is that nozzle temperatures are maintained at 20 degrees above ambient. Heat management is integral to Memjet printhead designs. Careful heat management enables continuous low energy printing as well as the tight nozzle configurations needed to achieve 1600 dpi print quality in one pass.

The Memjet nozzle layer is comprised of silicon nitride, an extremely durable composition, and coated with a surface material providing for a smooth, flat surface that resists debris and is easier to maintain.