Process for producing toner for developing electrostatic image and apparatus system therefor
US5111998A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 27, 1991 |
| Grant date | May 12, 1992 |
| Priority date | — |
| Expiry date | Mar 27, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G9/0817
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A toner for developing an electrostatic latent image is produced by classifying a pulverized feed material in a first classifying means into coarse powder and fine powder; pulverizing the coarse powder and feeding back the pulverized product to the first classifying means; introducing the fine powder to a second classifying means having a multi-division classification zone divided into at least three sections, where it is classified into a coarse powder portion, a median powder portion, and a fine powder portion; and feeding back the coarse powder to said pulverizing means or first classifying means. The median powder has a volume average particle diameter of from 4 .mu.m to 10 .mu.m and a coefficient of variation of number distribution, represented by A, satisfying the following condition: 20.ltoreq.A.ltoreq.45, and the weights B, C, F, G and M are controlled to satisfy the expressions: 0.3 .ltoreq.weight B/weight C.ltoreq.0.8, 0.2.ltoreq.weight G/weight C.ltoreq.0.7 and 0.8.ltoreq.weight B/(weight F+weight M).ltoreq.1.2.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.