D21G CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES (winders or rewinders for finished products, means for adjustment of wrinkles or lateral extensions B65H)
Introduced: September 1968
Description
D21G encompasses calendering equipment used in paper manufacturing to compress, smooth, and finish paper sheets, along with auxiliary devices integrated into papermaking lines. This includes calender rolls, nip structures, heating systems, and control mechanisms for regulating pressure, temperature, and sheet feed to achieve desired paper properties such as thickness uniformity, gloss, and density. The classification covers both standalone calendering units and machine components designed specifically to support the calendering process within integrated paper production systems.
Title
Titles differ between systems:
IPC: CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
CPC: CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES (winders or rewinders for finished products, means for adjustment of wrinkles or lateral extensions B65H)
Full Title
Full titles differ between systems:
CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES (winders or rewinders for finished products, means for adjustment of wrinkles or lateral extensions B65H)
IPC and CPC are identically structured here. All 5 subcodes exist in both systems.
1 shared codes have differing titles between IPC and CPC.
Child Classifications
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- D21G 1/00 Calenders (if restricted to the treatment of particular materials see the relevant class, e.g. B29C43/24, D06); Smoothing apparatus +5 CPC IPC+CPC Available in IPC and CPC
Top Applicants
Top Applicants (IPC)
Class D21,2013–2023, worldwide · Source: EPO PATSTAT
- VOITH PATENT DE 1,809
- STORA ENSO FI 1,467
- KEMIRA FI 1,086
- KIMBERLY-CLARK CORPORATION US 935
- VALMET TECHNOLOGIES FI 924
- VALMET SE 904
- P&G (PROCTER & GAMBLE COMPANY) US 862
- OJI HOLDINGS CORPORATION 696
- OMYA INTERNATIONAL CH 584
- SOUTH CHINA UNIVERSITY OF TECHNOLOGY 571
Top Applicants (CPC)
Class D21,2013–2023, worldwide · Source: EPO PATSTAT
- VOITH PATENT DE 1,857
- STORA ENSO FI 1,552
- KEMIRA FI 1,173
- KIMBERLY-CLARK CORPORATION US 1,107
- VALMET TECHNOLOGIES FI 965
- VALMET SE 943
- P&G (PROCTER & GAMBLE COMPANY) US 941
- OMYA INTERNATIONAL CH 821
- UPM-KYMMENE CORPORATION FI 512
- SEIKO EPSON CORPORATION JP 501