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Charge/Mass Particle Spectrometer

IP.com Disclosure Number: IPCOM000061241D
Original Publication Date: 1986-Jul-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Imaino, WI: AUTHOR [+3]

Abstract

In electrophotographic copiers and printers, charged black marking particles (toner) are attracted to and adhere to an electrostatic image on the photoconductor. We have found a device for measurement of charge-to-mass ratio of individual particles. A schematic diagram is shown in Fig. 1. The developer mix is used to blow the toner off the carrier beads. The toner particles enter an area of air flow directed toward the entrance aperture of the main chamber. Using a combination of filters and honeycomb structures, the air flow in the main chamber is laminar with a known transverse velocity profile. This is necessary for the tractable handling of the data. Toner particles that enter the main chamber are subjected to an electric field, causing the particles to move transversely toward or away from the metal electrodes.

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Charge/Mass Particle Spectrometer

In electrophotographic copiers and printers, charged black marking particles (toner) are attracted to and adhere to an electrostatic image on the photoconductor. We have found a device for measurement of charge-to-mass ratio of individual particles. A schematic diagram is shown in Fig. 1. The developer mix is used to blow the toner off the carrier beads. The toner particles enter an area of air flow directed toward the entrance aperture of the main chamber. Using a combination of filters and honeycomb structures, the air flow in the main chamber is laminar with a known transverse velocity profile. This is necessary for the tractable handling of the data. Toner particles that enter the main chamber are subjected to an electric field, causing the particles to move transversely toward or away from the metal electrodes. A combination of a beam expander and cylindrical lenses is used to shape the beam from a laser into a thin sheet of light (Fig. 2). Particles entering the light beam scatter light in one forward direction which is collected by a lens and focussed onto a position- sensing photodiode. The photodiode signals can be used to determine the position and size of each particle. This information is input into a personal computer and reduced to determine the charge-to-mass ratio of each particle. Using a combination of different technologies, i.e., forward light scattering and fluid dynamics, this device provides a heretofore un...