PURPOSE: To secure an ion outflow within the limit of the width of an ion flow control passage without impairing ion control, by making the length of the ion-flow control passage of an electrostatic latent image writing head two or less times greater than the width of the ion flow control passage.
CONSTITUTION: When the length (x) to width ratio of an ion flow control passage 19 is 2 or less times, an ion flow can be obtained basically even with no air flow and no air pressure, and, even when the width of the passage 19 is limited to a certain degree, an ion outflow can be secured because the ion outflow increases by increasing air pressure. Further, it is preferable that the length (x) to width ratio of the passage 19 be 1.5 or less times, so that a certain degree of an ion flow can be secured even with no air pressure, and because an ion outflow greatly increases by increasing air pressure, it is satisfactory. On the other hand, when the length (x) to width ratio of the passage 19 is 2 or more times, air pressure and an ion flow are not detected at all, and even the air pressure is increased, an increase in the ion flow is extremely small, so that a sufficient amount of ions can not be obtained.
TSUDA DAISUKE
ONO SHIGEO
