Electrostatic printer utilizing dehumidified air

• US 4,734,721 A
• Filed: 10/04/1985
• Issued: 03/29/1988
• Est. Priority Date: 10/04/1985
• Status: Expired due to Fees

• Current Assignee: Markem Corporation (Dover Corporation)
• Original Assignee: Markem Corporation (Dover Corporation)
• Inventors: Moore, Robert A., Boyer, Alan H., Walter, Graham D.
• Primary Examiner(s): Evans, Arthur G.
• Application Number:
  US06/784,506
• Time in Patent Office: 907 Days
• Field of Search: 346/154, 355/3 CH, 355/30, 313/432, 313/11, 313/28, 219/216 PH, 361/225, 361/230, 400/114, 101/DIG. 13, 358/300, 365/118
• US Class Current: 347/126
• CPC Class Codes: G03G 15/321 by charge transfer onto the recording material in accordance with the image
• CPC Class Codes: G03G 15/323 by modulating charged particles through holes or a slit

Abstract

An electrostatic print head system is disclosed which comprises an ion modulated electrostatic print head, a means for supplying unheated dehumidified air having a relative humidity of less than about 20 percent at or near ambient temperature, and a means for directing the dehumidified air at, near or through the print head. The print head may comprise a modulated aperture board having a plurality of selectively controlled apertures therein and an ion generator for providing ions for electrostatic projection through the apertures. The electrostatic print head system may be used for forming latent electrostatic images and employed in an electrostatic printer which further comprises a means for developing the latent electrostatic images.

Claims

1. An electrostatic print head system comprising:

(a) an ion modulated electrostatic print head,

(b) a means for supplying unheated dehumidified air having a relative humidity of less than about 20 percent at or near ambient temperature, and

(c) a means for directing the dehumidified air at, near or through the print head.

2. The electrostatic print head system of claim 1 wherein supply means (b) is capable of supplying unheated dehumidified air having a relative humidity of less than about 5 percent at or near ambient temperature.

3. The electrostatic print head system of claim 1 wherein the print head comprises a modulated aperture board having a plurality of selectively controlled apertures therein, and an ion generator for providing ions for electrostatic projection through the apertures, and wherein the dehumidified air can be directed to flow at or near the ion generator and at, near or through the apertures.

4. The electrostatic print head system of claim 3 wherein the apertures function to cut off the flow of ions, and wherein the ion generator is a corona wire.

5. An electrostatic printer comprising:

(a) an ion modulated electrostatic print head for forming latent electrostatic images,

(b) a means for developing the latent electrostatic images,

(c) a means for supplying unheated dehumidified air having a relative humidity of less than about 20 percent at or near ambient temperature, and

(d) a means for directing the dehumidified air at, near or through the print head.

6. The electrostatic printer of claim 5 wherein supply means (b) is capable of supplying unheated dehumidified air having a relative humidity of less than about 5 percent at or near ambient temperature.

7. The electrostatic printer of claim 5 wherein the printer comprises a modulated aperture board having a plurality of selectively controlled apertures therein, and an ion generator for providing ions for electrostatic projection through the apertures, and wherein the dehumidified air can be directed to flow at or near the ion generator and at, near or through the apertures.

8. The electrostatic printer of claim 7 wherein the apertures function to cut off the flow of ions, and wherein the ion generator is a corona wire.

9. An electrostatic imaging process which comprises the steps of:

(a) forming a latent electrostatic image on a dielectric imaging surface using an ion modulated electrostatic print head,

(b) developing the latent electrostatic image,

(c) providing unheated dehumidified air having a relative humidity of less than about 20 percent at or near ambient temperature, and

(d) directing the dehumidified air at, near or through the print head.

10. The electrostatic imaging process of claim 9 wherein the print head comprises a modulated aperture board having a plurality of selectively controlled apertures therein, and an ion generator for providing ions for electrostatic projection through the apertures, and

wherein the dehumidified air is directed at or near the ion generator and at, near or through the apertures.

11. The electrostatic imaging process of claim 10 wherein the apertures function to cut off the flow of ions, and wherein the ion generator is a corona wire.

12. The electrostatic imaging process of claim 9 wherein the dehumidified air has a relative humidity of less than about 5 percent at or near ambient temperature.