Powdertech Co., Ltd.
92Patents
68Active
92Granted
47Portfolio score
Filing activity: Nov 27, 1991 → Feb 7, 2022 · 22 expiring within 5 years
Most-cited patents
| Patent | Title | Area | Cited by | Status |
|---|---|---|---|---|
| US5595850A | Ferrite carrier for electrophotographic developer and developer containing the carrier | Physics | 26 | Expired |
| US5204204A | Carrier for developing electrostatic latent image | Physics | 18 | Expired |
| US5466552A | Ferrite carrier for electrophotographic developer and developer containing the carrier | Physics | 16 | Expired |
| US5798198A | Non-stoichiometric lithium ferrite carrier | Physics | 13 | Expired |
| US5419994A | Carrier for electrophotographic developer, process for preparing the same and developer prepared by using said carrier | Physics | 11 | Expired |
| US6235443A | Carrier for electrophotographic developer and electrophotographic developer containing the same | Physics | 9 | Expired |
| US5518849A | Ferrite carrier for electrophotographic developer and developer using said carrier | Physics | 8 | Expired |
| US5976747A | Ferrite carrier for electrophotographic developer and electrophotographic developer containing the same | Physics | 8 | Expired |
| US6294304A | Environmentally benign high conductivity ferrite carrier with widely variable magnetic moment | Physics | 7 | Expired |
| US7566519B2 | Carrier for electrophotographic developer, and electrophotographic developer using the same | Physics | 6 | Active |
| US6210850A | Carrier for electrophotographic developer and electrophotographic developer containing the same | Physics | 6 | Expired |
| US7442483B2 | Ferrite carrier for electrophotographic developer and method for preparing the same, and electrophotographic developer using the same | Physics | 5 | Expired |
| US6544707B2 | Two component developing agent and an image forming apparatus by use of the same | Physics | 4 | Expired |
| US7921798B2 | Oxygen detector sheet and oxygen detecting agent using the same, and method for manufacturing oxygen detector sheet | Emerging Cross-Sectional Technologies | 4 | Active |
| US5491042A | Method for manufacturing a resin-coated carrier for an electrophotographic developer | Physics | 4 | Expired |
| US8465898B2 | Ferrite carrier core material and ferrite carrier for electrophotographic developer, and electrophotographic developer using the ferrite carrier | Physics | 4 | Active |
| US7521163B2 | Resin-coated ferrite carrier for electrophotographic developer, its production method, and electrophotographic developer using the resin-coated ferrite carrier | Physics | 4 | Active |
| US7553597B2 | Carrier core material, coated carrier, and two-component developing agent for electrophotography | Emerging Cross-Sectional Technologies | 3 | Expired |
| US7183033B2 | Carrier core material, coated carrier, two-component developing agent for electrophotography, and image forming method | Physics | 3 | Expired |
| US6387582B2 | Carrier for electrophotographic developer and electrophotographic developer containing the same | Physics | 3 | Expired |
| US9372426B2 | Ferrite particle having outer shell structure, ferrite carrier core material for electrophotographic developer, and electrophotographic developer | Chemistry; Metallurgy | 2 | Active |
| US8535867B2 | Ferrite core material and ferrite carrier for electrophotographic developer, and electrophotographic developer using the ferrite carrier | Physics | 2 | Active |
| US10825593B2 | Ni—Zn—Cu ferrite particle, resin composition, and resin molding | Electricity | 2 | Active |
| US8475988B2 | Resin-filled ferrite carrier core material for electrophotographic developer, ferrite carrier and electrophotographic developer using the ferrite carrier | Physics | 2 | Active |
| US6071663A | Carrier for electrophotographic development and electrophotographic developer containing the same | Physics | 2 | Expired |
Source: USPTO / EPO open patent data. Counts and citation impact are objective bibliographic measures.