CPC Subclass Not Allocatable
D21G CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES (winders or rewinders for finished products, means for adjustment of wrinkles or lateral extensions B65H)
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.
5 direct subcodes
Child Classifications
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Top Applicants
Top 10 applicants by patent filingsfor 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