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EP0550880A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Image forming device

Assignee: Sharp Corp
•
Filing: 1992-12-23
•
Granted: —
•
Expires: 2012-12-23
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Abstract

Abstract In an image-forming device, a toner image can be formed on a recording element (2) on the condition that a control grid (7) always keeps the repulsing force constant to the toner (T). As a result, the control grid (7) is kept free from clogging of its openings with toner particles. While toner (T) on a toner carrier (5) is charged with negative polarity an attracted by applying positive voltage to a backing electrode (8) placed at the back of a transfer belt (2), voltage applied across the electrodes arranged crosswise in directions X and Y of the control grid (7) disposed between the transfer belt (2) and the toner (T) is changed so as to vary the toner repulsing force in space-charged openings of the control grid (7), thereby regulating the amount of toner (T) passing therethrough.

Inventors

  • 👤 Takasumi Wada

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-09 14:56
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/385; B41J2/41; B41J2/415; B41J2/4155; G; G03; G03G; G03G15/00; G03G15/22; G03G15/34; G03G15/344; G03G15/346; G03G2217/00; G03G2217/0008; G03G2217/0025

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 199 words
An image-forming device, characterized by: a toner carrier (5) for polarizing and carrying toner (T); a backing electrode (7) placed facing the toner carrier and supplied with voltage of an opposite polarity to the toner carrier (5); a control grid (7) placed between the toner carrier (5) and the backing electrode (8) for controlling the movement of the toner (T) from the toner carrier (5) to the backing electrode (8); a recording element (2) movable between the control grid (7) and the backing electrode (8); and a control voltage applying means for adjusting voltage applied to the control grid (7); the control grid (7) comprises wire electrodes extending in a first (X) direction to carry the recording element (2) and wire electrodes extending in a second (Y) direction intersecting the first (X) direction; the control voltage applying means applying voltage having the same polarity as that of the toner (T) to each of the electrodes in both directions (X and Y) in such a way that toner-repulsing force produced by an electrical field within each of the grid openings is selectively changed to a larger or smaller one that the toner attracting force produced by the backing electrode (8).
Claim 2
Dependent Claim 56 words
An image-forming device according to Claim 1, characterized in that the control grid (7) is composed of units of control electrodes (X1, X2,...; Y1, Y2,...) which are wire electrodes (XNL, XNR; YNL, YNR) spaced in parallel and connected with each other at least at one end and arranged crosswise in the said directions (X and Y).
Claim 3
Dependent Claim 39 words
An image forming device according to Claim 1 or 2, characterized in that the units of control electrodes (X1,X2,...; Y1, Y2,...) extending in the first (X) direction are disposed diagonally in the direction of carrying the recording element (2).
Claim 4
Dependent Claim 39 words
An image forming device according to Claims 1 to 3, characterized in that the toner carrier (5) has a rotary cylinder (5b) including therein a stationary permanent magnet which holds the toner on the cylinder's surface by magnetic force.
Claim 5
Dependent Claim 44 words
An image-forming device according to Claim 4, characterized in that the permanent magnet has a groove (5c) extending in the second (Y) direction on its surface facing the backing electrode (8) and producing a repulsing magnetic field at the upper portion of the groove.

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