US 5933161

I'll search for this specific patent number across the USPTO and CAFC sources.

Let me pull the full claim set and check for any litigation or CAFC activity.

US Patent 5,933,161 — Summary

Important caveat on identifiers: Per the strict literal-interpretation rule, I did not merge results for look-alike IDs. Searches for the bare string "5933161" also surface U.S. Trademark Registration No. 5,933,161 ("EMPIRICAL," Empirical Innovations, Inc.) and JP5933161B2 (a Japanese lighting-device patent). Neither is the subject of this request; only the U.S. patent grant is summarized below.

Uncertainty notice: I could not query USPTO Patent Center/PTAB or the Federal Circuit docket directly; the findings below come from web-search results (Google Patents, Justia, EPO/third-party indexes). Where a field rests only on one source, I flag it.

Bibliographic data

Abstract (as published)

An ink-jet recorder having an arrangement of a plurality of heat-generating elements, drivers for driving them, and a drive circuit for controlling the drivers according to image data, wherein the drive circuit includes a split-block drive circuit that divides the heat-generating elements into a plurality of blocks and drives them block-by-block in a time-sharing manner, and a data retaining circuit for retaining print data; and the split-block drive circuit (i) drives each block at printing operations using a pre-pulse during which ink is not squirted and a main pulse during which ink is squirted, and (ii) drives another group of heat-generating elements different from the currently driven group during intervals between the pre-pulse and the main pulse.

Independent claims (plain language)

Claim 1 — the ink-jet recorder (apparatus). A thermal ink-jet recorder has (a) many heat-generating elements, (b) drivers that energize them, and (c) a drive circuit that controls those drivers in accordance with image data. The drive circuit has two cooperating parts: a split-block drive circuit that groups the heat-generating elements into blocks and fires them one block at a time (time-sharing), generating a pre-pulse and a main pulse; and a data retaining circuit that holds the print data and switches which retained data is being used depending on whether the elements are being driven by the pre-pulse or by the main pulse. The blocks are driven using a pre-pulse (heating but no ink ejection) followed by a main pulse (ink ejection), and — the key point — while one block is between its pre-pulse and its main pulse, a different block is driven. Practically, this hides dead time in the double-pulse waveform and speeds up printing while limiting how many elements fire simultaneously.

Claim 18 — the ink-jet recording head / substrate. This is the structural layout claim. An ink-jet recording head has a substrate carrying the heat-generating elements, the drivers, and the drive circuit. It includes the same split-block drive circuit (pre-pulse/main pulse) and the switching data-retaining circuit, and additionally requires that input lines of the drive circuit, corresponding to the heat-generating elements, be routed on the substrate so as to cross at least one of the block drive lines, with the block drive line connected to the relevant input line at the intersection. The commercial point is a cross-bar/matrix routing scheme, so the wiring assignment can be changed by moving contact locations rather than redesigning the chip.

Dependent claims (context for the independents)

Claims 2–17 depend from claim 1 and add: only four external signals (print data, data-transfer clock, drive signal containing pre/main pulse, reset) (cl. 2); alternating pre/main pulses used for different blocks (cl. 3); using the print-data signal to carry block-order-switching data together with the reset signal (cl. 4); retaining no more than twice one block's worth of print data (cl. 5); shift register + latch + delay + selection circuit architecture (cl. 6); switchable single-pulse versus double-pulse driving selected by input-signal sequence (cl. 7); bidirectional block drive order (cl. 8); multiple bidirectional counters selecting one block (cl. 9); AND/arithmetic logic per element fed by counter and data outputs (cl. 10); asynchronous binary counters with AND-gate clock chaining giving sub-flip-flop per-stage delay (cl. 11); selection of flip-flop outputs/inverted outputs for bidirectional drive (cl. 12); selecting a block for the main pulse that was pre-pulsed earlier (cl. 13); pre-driver section and regulator with standby mode fed from the common electrode (cl. 14); polysilicon heat-generating elements with MOS-transistor drivers (cl. 16); and first/second test terminals outputting part of the block-selection and data signals (cl. 17). Claim 19 depends from claim 18 and requires the quotient of (total heat-generating elements ÷ maximum simultaneously printable characters) to be factorable.

Note on numbering: the specification discusses the subject matter as "first" through "eighteenth aspect," which runs one lower than the granted claim numbers (e.g., spec "fifteenth aspect" appears as granted claim 16). I have stated the granted numbers shown by the claim listings; the exact dependency of claim 17 is the one point I could not fully verify from the sources retrieved.

Litigation / CAFC check

• No Federal Circuit or district-court action involving US 5,933,161 was found in my searches, and specifically nothing linking this patent to a CAFC 2026 docket was retrieved. Because I could not query the CAFC docket system or PACER directly, treat this as "not found," not as an affirmative confirmation that no such proceeding exists.
• The patent's footprint in the record is as prior art: it is cited in later patents' reference lists (e.g., US 8,740,350 and US 7,559,626, both Canon) and in EPO search reports against later applications, where it is cited as an "A" (background) and "Y" (combined-obviousness) reference against claims 1, 13 and 14 (see e.g. the EP 0 993 103/1 016 524 search-report PDFs and EP 0630752A3 citation listing). It also appears among a Lexmark petition's prior-art query list (ptacts.uspto.gov petition 1550157).
• Relevance to high-density packaging: the patent's stated aim — cutting substrate cost and enabling high-density packaging by reducing wire count and integrating a compact double-pulse drive circuit on the heater substrate — is consistent with why it recurs as background art in Canon's heater-board driver-circuit patents.

Bottom line

US 5,933,161 (Fuji Xerox; Sato et al.; filed 1997-03-18, issued 1999-08-03, priority 1996-03-21) claims a thermal ink-jet recorder whose on-substrate drive circuit time-shares the heater array into blocks and interleaves the "other block" firing inside the pre-pulse/main-pulse gap, with the data-retaining circuit swapping between pre-pulse and main-pulse data. Granted claim 18 adds a substrate routing/matrix-crossing limitation for flexible wiring changes. The patent expired in 2017 for failure to pay maintenance fees, and no court or CAFC activity involving it was located in this search.