Black toner with defined loss tangent
US7300733B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 14, 2005 |
| Grant date | Nov 27, 2007 |
| Priority date | — |
| Expiry date | Sep 14, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G9/09783
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
To provide a black toner having excellent charging property and transferring property against a severe environmental change. The black toner includes toner particle containing at least a binder resin, carbon black and a releasing agent, wherein: the toner particles have a weight-average particle diameter of 3.5 to 8.0 μm; total amount of acid value and hydroxyl value of the toner is 30 to 75 mgKOH/g; average circularity of particles contained in the toner having circle-equivalent diameter of 2 μm or more is 0.915 to 0.960; loss tangent tanδ (103 to 104 Hz) of the toner is represented by the following expression:tanδ (103 to 104 Hz)≦0.0060where the loss tangent tanδ is represented by ε″/ε′ where ε″ denotes dielectric loss factor and ε′ denotes dielectric constant, and tanδ (103 to 104 Hz) denotes the loss tangent in a frequency range of 103 to 104 Hz; and a ratio of tanδ (105 Hz) to tanδ (5×104 Hz) is represented by the following expression:1.05≦tanδ (105 Hz)/tanδ (5×104 Hz)≦1.40where tanδ (105 Hz) denotes loss tangent at the frequency of 105 Hz and tanδ (5×104 Hz) denotes loss tangent at the frequency of 5×104 Hz.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.