Buffer reservoir for a liquid-ink writing instrument, and a writing instrument including such a reservoir
US5927885A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 14, 1997 |
| Grant date | Jul 27, 1999 |
| Priority date | — |
| Expiry date | Apr 14, 2017 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB43K8/04
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A buffer reservoir suitable for absorbing surplus ink and a writing instrument including the buffer reservoir are provided. The buffer reservoir includes a mixture of microbeads that are hydrophobic relative to the ink and microbeads that are hydrophilic relative to the ink. The mixture of microbeads may either be uniform throughout the entire volume of the buffer reservoir, or non-uniform throughout the entire volume of the buffer reservoir, with the proportion of hydrophilic microbeads to hydrophobic microbeads being smaller in the zone immediately in contact with the feed tip and larger in the zone farthest away from the feed tip. Preferably, the proportion of hydrophilic microbeads is in the range of about 2% to about 10%, by weight, relative to the total weight of the buffer reservoir. The writing instrument includes a reservoir for liquid ink, a feed tip opening out into the reservoir, and a buffer reservoir.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.