| 摘要 |
<p>In a direct printing device, charged toner particles are subjected to an electric field to transport them to an image-receiving medium (1). The electric field is generated by a back electrode (12) located below the image-receiving medium. A printhead (5) located in the electric field has a plurality of apertures through which toner particles are selectively transported. Ring electrodes (53) on each aperture control the opening and closing of the apertures. Deflection electrodes (54) are also provided on each aperture to selectively generate asymmetric electric fields around the apertures, causing toner particles to be deflected. By providing a deflection controller to alter the potential difference between the back electrode and deflection electrodes as a function of time during the movement of toner particles towards the back electrode the toner trajectory can be changed to impact on the image-receiving medium substantially normally. The device is thus rendered largely insensitive to variations in distance between the printhead and the image-receiving medium and improved print quality is obtained.</p> |
