Influence in this dataset is best measured by citation count within the searched corpus, and the most-cited records are WO2008074548A1 on dispersion stability for white inkjet ink and EP1911814A1 on curable pigment inkjet ink sets, both cited well over 200 times by later filings. High citation counts favour older records simply because they have had more time to be cited, so treat this as a measure of historical influence on the field rather than a statement about which company is strongest today. Recent-year filing momentum data shows several of the historically largest filers, including major Japanese imaging and ink companies, recording zero filings in the latest tracked year, so influence and current activity are not the same signal.

Filings peaked in 2017 at 434 records and have trended down since, with the 2022 midpoint at 284 and further decline through to the most recent years. This looks like a flat-to-declining filing pattern rather than a growth market by patent volume. Keep in mind that publication typically lags filing by around 18 months, so the very latest year in any dataset always understates actual filing activity and should be treated as provisional rather than a confirmed drop-off.

C09D, the coatings, paints and inks class, covers the large majority of records in this dataset at 6,679 out of 7,056 total, making it the class where most claim language and prior art density sits. B41J (printers) and B41M (printing processes) are the next largest, reflecting that many inkjet ink claims are drafted alongside the print-head and process context they are used in. Smaller adjacent classes — C09B and C09C for pigments, C08K and C08F for additives, and D06P for textile dyeing — carry far fewer records and are worth checking specifically if your formulation sits closer to those adjacencies than to core coatings chemistry.

US20240158656A1, filed by DIC Corporation, claims a pigment dispersion for inkjet ink built around a non-cross-linked dispersant resin whose acid groups are neutralised by a tertiary alkanolamine at a neutralisation rate above the theoretical 100% equivalent and up to 200%, using an amine with two to three hydroxyl groups and a boiling point between 150 and 330°C. This is a narrow, parameter-bound claim rather than a broad dispersion-chemistry claim, so it only reads on formulations that fall inside all of those numeric limitations at once. If your dispersant system uses a different neutraliser class, a lower neutralisation rate, or an amine outside the stated boiling-point or hydroxyl-count range, it sits outside the literal scope of this claim as described, though a full claim chart is the only reliable way to confirm freedom to operate.

The thinnest IPC coverage in this dataset sits in D06P (textile dyeing and printing) at 264 records and C09C (inorganic pigment treatment) at 223, both far below the core coatings and printing-process classes. Additive polymer chemistry (C08F, C08K) is similarly light relative to how central additives are to jetting reliability and drying performance. With only ten recorded co-assignee pairs across the whole corpus, there is also very little cross-company joint filing, which suggests room for formulations that bridge two of these thinner branches — for example a textile-substrate-compatible pigment dispersion with a specified inorganic surface treatment — without immediately colliding with a dense existing claim set.