| 摘要 |
Printing apparatus of the type which is named "toner jet" printing apparatus, and in which a dry colour powder, generally named "toner", by a direct process is transferred from a rotary toner feeder roll (1) having a predetermined relatively low positive potential (for instance +50 V), through toner feeder apertures (8) of a fixed toner matrix (3) in the form of a flexible printing circuit and down to an object to be printed, for instance a paper, which is moved over a support roll (4) having a predetermined relatively high potential (for instance +1500 V), and in which the toner which has deposited on the paper (5) is finally fixed on the paper by a heat treatment means (12), and in which each toner feeder aperture (8) of the matrix (3) is surrounded by an electrically conducting control ring (9) which is mounted on top of the matrix base (13) with the inner diameter thereof edge to edge with the toner feeder apertures (8), and in which the matrix (3) is laminated to a laminator plate (14) provided over the bottom surface thereof, which plate (14) is of an unmagnetic metal. The matrix (3) is bowed in a curvature extending parallel to the toner feeder roll (1). The entire matrix, including the control rings (9), the laminator plate (14) and the aperture edges are coated with a thin layer (17) of an insulating material.
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