1. HP Optical Media Advance System (OMAS)

3. Media Advancemotion encoding (1) • Most large format printers measure motion of the media indirectly by encoding an element in the drive system • motor shaft (least accurate) • final drive roller (most accurate) • The drive system can be calibratedby comparing input (motor) and output (media) motions to minimize systematic errors from... • media physical properties • media slippage • Indirect measurements are... • adequate for moves less than ~1 inch • subject to errors from • media slippage • temperature and humidity changes • mechanical tolerances and wear encoder mediadrive motor final drive roller final drive roller encoder print zone

4. Media Advancesteady advances in accuracy • Since 1990, HP has achieved a 20X improvement in the accuracy of encoder-based media advance systems in HP Designjet printers • Improvements are driven by • larger print swaths, longer moves • need for higher image qualityat higher throughput • Encoder-based systems are reaching practical limits at ~1um/mm (0.1%) • requires high mechanical precision • increases manufacturing cost • Wider printheads and HP Double Swath Technology need longer mediamoves to achieve potential speed • accuracies better than 0.5um/mm are needed for long moves (~2 inches) • a performance breakthrough is neededin media advance accuracy Media Advance Accuracy (um/mm) 100.0 10.0 DJ 4000 DJ 5500 1.0 target 0.1 1985 1990 1995 2000 2005 2010 HP Designjets by Year of Introduction

7. better OMASeffective improvement in image quality • Results from comparative testing with and without OMAS • internal HP tests with a pool of image quality judges • controlled viewing environment • best sample rated “100” • images ranked in bands: “better”, “worse”, “acceptable” • CAD drawing, Normal Mode, HP Bond Paper mean value confidence band Banding(higher number = better) Line Smoothness(higher number = better) no OMAS30% RH 100 100 no OMAS30% RH 80 80 60 60 no OMAS70% RH Relative image quality OMAS30% RH OMAS70% RH no OMAS70% RH 40 40 OMAS30% RH OMAS70% RH 20 20 0 0 Samples printed with OMAS show less banding and better line smoothness. Consistent OMAS results for printing conditions between 30% and 70% RH.

9. AB dX Image A dY OMAShow it works (1) media back side • OMAS takes images A and B in two “windows” • Separation distance AB (~3mm) is measured with high precision during OMAS manufacture • AB is stored in the OMAS EEPROM windowA • OMAS stores reference image A from window A • The media moves ~AB in the X-direction • window B now sees the same region of the media that was stored in reference image A X windowB • OMAS takes new images A’ and B’ • window A: image A’ (used for the next AB step) • window B: image B’ (used to match with image A) • image B’ is now correlated (matched) to image A • algorithms compute the offsets dX and dY between images A and B’ • OMAS reports the media has moved ΔX = AB + dX • dX and dY will be different on each AB step • dX and dY may be positive or negative Image B’