A Study on the Low Energy Consumption Thermal Head Using Electroless Ni‐W‐P Alloy Films as Heating Resistors

Abstract

The new type of thermal head with an electroless Ni-W-P film on a polyimide film substrate was investigated for the purpose of low cost and low energy consumption. The electroless plating method attained a fine patterned heating element and the polyimide substrate worked as a heat-insulating layer with a lower heat conductivity. In our simulation, the applied power was reduced about 50% by using polyimide film as the heat-insulating layer. The accumulation of heat could be suppressed by controlling the polyimide film thickness without reducing the advantage of low energy consumption. The new head, composed of screen-printed polyimide resin with SiC powder (10 ~m thick) as the protective layer, an electroless Ni-W-P film (0.25 i~m thick) as the heating element, a polyimide film (50 i~m thick) as the heat-insulating layer, and an A1 board (3.0 mm) as the heat sink, was produced. The new head shows the same dot size as that of the conventional thin-film-type head produced by vacuum technology, and its cost is lower than that of the conventional thin-film-type head. The new head produces the good printing quality with 60% of the power required by the conventional one. Therefore, the new head provides low cost and low energy consumption.

Progress of electroless amorphous and nano alloy deposition: a review – Part 2

“…Of the ternary alloy Ni-P deposits, Ni-Mo-P [192][193][194][195] , Ni-W-P [196][197][198][199][200] and Ni-Cu-P [201][202][203][204][205][206] were most studied, although reports have been found on Ni-Fe-P, 207 Ni-Cr-P, 207 Ni-Re-P, 208 Ni-Zn-P, 209-211, , Ni-Sn-P, 212,213 and Ni-Sb-P. 213 For Ni-B, there were also few reports: Ni-Mo-B, 214 Ni-Fe-B, 215 Ni-Co-B, 216 Ni-Cu-B, 217 and Ni-Sn-B 212 . In addition, Co-Ni-P and Co-W-P was studied by Georgiou et al in 1991.…”

Studies on design, fabrication and reliability assessment of embedded passives on a high-density interconnect (HDI) organic substrate using a sequential build-up process

“…Acid hypophosphite-based baths were used in this work for their low pH (most polymers can withstand low pH baths). The composition of the electroless plating bath for Ni-W-P alloys [7][8][9] is summarized in Table I and a process flow is given below in Fig 9. Thicknesses achieved are of the 3-5 microns and the adhesion strength is comparable to swell and etch chemistry process which is well established in the industry. The peel strength of the deposits are of the order of 1-1.5N/mm.…”

“…Materials requirements for embedded resistors can largely be satisfied by choosing materials systems that will provide sheet resistance in the range of (i) 5 to 50 Ω/sq, (ii) 500 to 1000 Ω/sq, and (iii) 5K to 40 KΩ/sq with a temperature coefficient of resistance (TCR) on the order of +/-50 ppm/ o C. Besides materials, there are challenges in process integration such as large area fabrication with good reproducibility and yield, materials stability, variations in length, width and thickness of the deposited thin film, contact resistance, smoother substrate to reduce noise, trimming, and development of low cost fabrication processes. Among the many materials referred to in the literature, electroless plating [7][8][9] appears to be a good approach to meet the required goal in the low-value resistors. This paper presents a method that offers low temperature processing for organic board compatibility.…”

Electroless deposition of ternary Ni–W–P alloys from sulphate and chloride based baths

“…8 Ni-W-P alloy films find application as heat resistors in low energy consumption thermal heads, which are used in printing operations. 9 Codeposition of tungsten in Ni-P matrix reduces the phosphorus content of the deposit and alters the crystal structure accordingly. 10,11 The amorphous nature of the coating depends mainly on the phosphorus content, but is also partly dependent on other alloying additions.…”