Paper: Flow of particulates, toners and carriers in a housing cavity
Abstract:Flow of small particles micron in size is important in several industrial applications such as digital imaging, polymer processing, powder coating and in dispersing fertilizers to name a few. In digital imaging toner particles surrounded by silica or titanium are triboelectrically mixed with carrier particles to form developer particles. The toner particles are then separated from carrier particles by electric field and conveyed to photoreceptor for development. Optimum flow rates of both toner particles and of developer particles are essential for development process. Interparticle forces, bulk properties (compressibility and cohesion) and stresses (frictional, cohesive and viscous stresses) are used to analyze powder flow. In inter-particle forces, the presence of humidity can result in capillary forces (surface tension) being important along with both electrostatic and van der Waal forces in affecting toner and developer flow. Several models can be put forth to explain the mechanisms of charges on toner and developer particles and their effect on flow. Correspondingly, hardness and modulus of a particle or particles are important material variables in van der Waal forces. Flow of toner particles and developers in a housing is analyzed by considering driving force from applied shear energy (rotating augers) against constraints of extrinsic constraints (consolidation, boundary) and intrinsic constraints (cohesion, compressibility and inter-particle forces). Both Discrete Element Method (DEM) and Continuum Models have been used to analyze powder flow with DEM uses models at particle level and is therefore requires costly computation where as Continuum Models are less accurate for complicated geometries and free surfaces. Empirical correlations are costly to obtain for predicting developer flow from frequent bench experiments (Freeman tester, Jenike shear cell and Seville tester) and tests in fixtures and housings.
Document Type: Research Article
Publication date: 2007-01-01
For more than 25 years, NIP has been the leading forum for discussion of advances and new directions in non-impact and digital printing technologies. A comprehensive, industry-wide conference, this meeting includes all aspects of the hardware, materials, software, images, and applications associated with digital printing systems, including drop-on-demand ink jet, wide format ink jet, desktop and continuous ink jet, toner-based electrophotographic printers, production digital printing systems, and thermal printing systems, as well as the engineering capability, optimization, and science involved in these fields.
Since 2005, NIP has been held in conjunction with the Digital Fabrication Conference.
- Information for Authors
- Submit a Paper
- Subscribe to this Title
- Membership Information
- Terms & Conditions
- Ingenta Connect is not responsible for the content or availability of external websites