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CPC technology class · D21

D21F - Paper-making Machines

Paper-making machines; methods of producing paper thereon. 1,255 US utility patents granted 2015–2025, with the leading assignees and year-by-year filing trajectory.

1,255
US patents granted
D21
Parent CPC class
20
Active assignees
+49%
5-yr velocity

The verdict

Paper-making Machines ranks #425 of 670 CPC technology areas - 1,255 US patents granted since 2015, with filing up 49% over five years.

#425
of 670 CPC technology areas
1,255
US patents granted, 2015–2025
Seiko Epson
leading assignee (155)
+49%
filing velocity, last 5 yrs
Top assignee: Seiko Epson Corporation (155 patents)

CPC subclass D21F - PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON - covers 1,255 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records, within the broader CPC class D21 (PAPER-MAKING; PRODUCTION OF CELLULOSE). See our CPC classification guide for how the system works.

The competitive landscape in D21F is shaped by 20 distinct companies actively filing in this space. Seiko Epson Corporation leads with 155 patents, followed by Kimberly-clark Worldwide, Inc. at 73 grants and GPCP IP Holdings Llc at 60.

Filing activity in D21F is up 49% over the past five years versus 2015-2019, a sharp acceleration suggesting an emerging or fast-moving technology area. All counts come directly from USPTO PatentsView and reflect US granted utility patents only.

Is D21F innovation accelerating?

US utility-patent grants per year in D21F, 2015–2025 - recent five years are up 49% versus 2015–2019.

6080100120140160 20152016201720182019202020212022202320242025 85

Who leads D21F?

The 12 most active assignees in PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON - wider bars mean more grants

patents

What this shows Seiko Epson is the most active filer in D21F, holding 155 of the 1,255 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.

Source USPTO PatentsView, granted utility patents As of 2015–2025 grant years
View data table
Top patent holders in CPC subclass D21F
Rank Company Patents in D21F
#1 Voith Patent Gmbh 114
#2 Kimberly-clark Worldwide, Inc. 73
#3 GPCP IP Holdings Llc 60
#4 Stora Enso OYJ 32
#5 First Quality Tissue, Llc 32
#6 Albany International Corp 25
#7 Astenjohnson, Inc. 24
#8 Georgia-pacific Consumer Products Lp 23
#9 Valmet Technologies Oy 23
#10 Ichikawa Co., Ltd. 23
#11 International Paper Company 22
#12 Valmet Aktiebolag 22
#13 Structured I, Llc 21
#14 Andritz Inc. 19
#15 IBS Of America 17
#16 Valmet Technologies, Inc. 16
#17 Nippon Filcon Co., Ltd. 16
#18 Valmet AB 11
#19 Stowe Woodward Licensco Llc 11
#20 Kemira OYJ 9

About This Class

CPC subclass D21F belongs to class D21.

1,255 patents were granted in this class between 2015 and 2025.

20 companies actively patent in this space.

Classification System

Cooperative Patent Classification (CPC) is a hierarchical patent classification system used by the USPTO and EPO.

← All Technology Classes Technology Rankings →

Footprint here vs. claim strategy

Each dot is a leading D21F assignee, placed by how many patents it holds in this class (horizontal) against its company-wide average claims per patent (vertical) - a read on whether the class is led by broad-but-shallow filers or focused deep-claim players.

Top 14 D21F assignees by class footprint. Bubble size = patents in D21F. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Top 14 D21F assignees by class footprint. Bubble size = patents in D21F. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 10152025 050100150 Patents in D21F Avg claims / patent (company-wide) Voith PatentKimberly-clark Worldw…Gpcp Ip HoldingsStora Enso OyjFirst Quality TissueAlbany InternationalAstenjohnsonGeorgia-pacific Consu…Valmet OyIchikawaInternational PaperValmet AktiebolagStructured IAndritz
Top 14 D21F assignees by class footprint. Bubble size = patents in D21F. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class D21F?
CPC subclass D21F covers PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON. It belongs to CPC class D21 (PAPER-MAKING; PRODUCTION OF CELLULOSE), with 1,255 US utility patents granted since 2015.
How many patents have been filed in D21F?
1,255 US utility patents were granted in CPC subclass D21F between 2015 and 2025, based on USPTO PatentsView data.
Which company holds the most patents in D21F?
Seiko Epson Corporation leads D21F with 155 patents, making it the most active assignee in this technology area.
How is patent data for D21F collected?
Patent data comes from USPTO PatentsView, a public research dataset maintained by the United States Patent and Trademark Office. It covers all US granted utility patents and assigns CPC codes based on the technology described in each patent.
What is the difference between CPC class and subclass?
A CPC class (e.g., D21) is a broad technology category. Subclasses like D21F provide finer granularity within that category. PlainPatent organizes data at the subclass level (4-character codes) for the most useful view of technology domains.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from USPTO PatentsView - official U.S. government patent data. See our methodology for computation details. Retrieved and formatted by PlainPatent Editorial

Every figure on PlainPatent is rendered directly from USPTO source data, no number is typed in by an editor. This page draws directly on USPTO source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.