# US 4,243,726 A · Structured donor sheet for high-resolution non-impact printer

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- Number: US 4,243,726 A
- Document ID: US4243726A
- Status: Granted
- Kind: A
- Application number: 05/919,816
- Filed: 1978-06-28
- Granted: 1981-01-06
- Earliest claimed: 1976-07-30
- Assignees: EPP Corp.
- Inventors: Donald J. J. Lennon; Roger E. Clapp
- Web page: https://patentgrep.com/patent/US4243726A

## CPC

- B41M 5/10: by using carbon paper or the like
- Y10S 428/90: Magnetic feature
- Y10T 428/12007: Component of composite having metal continuous phase interengaged with nonmetal continuous phase
- Y10T 428/12028: Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]
- Y10T 428/12389: having variation in thickness
- Y10T 428/12465: having magnetic properties, or preformed fiber orientation coordinate with shape
- Y10T 428/12993: Surface feature [e.g., rough, mirror]
- Y10T 428/2438: Coated
- Y10T 428/24388: Silicon containing coating
- Y10T 428/24413: Metal or metal compound
- Y10T 428/24545: Containing metal or metal compound
- Y10T 428/24975: No layer or component greater than 5 mils thick
- B41M: PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING, (correction of typographical errors B41J; processes for applying transfer pictures or the like B44C1/16; fluid media for correction of typographical errors by coating C09D10/00; printing textiles D06P)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Structures for supporting printing articles in spaced aggregates as mounds and towers, for use in pulsed electrical printers, and method for their production. The structures comprise a base sheet having a roughened or microcavernous surface to receive the printing particles. The base sheet may be formed of or coated with conductive material, and may comprise a magnetizable material useful in forming and retaining the aggregates.

## Claims

### Claim 1

A donor sheet useful in pulsed electrical printing, comprising
a conductive base sheet having a microcavernous surface, and
print particles having a conductivity at least that of a semi-conductor lying in spaced irregular mounds and towers on said surface, said donor sheet having a lateral surface D.C. resistivity less than 100,000 ohms per square.

### Claim 2 (depends on 1)

A donor sheet according to claim 1, in which the base sheet is metallic.

### Claim 3 (depends on 1)

A donor sheet according to claim 1, in which the base sheet comprises a material of high electrical resistivity having a microcavernous surface, and a metallic coating over said microcavernous surface.

### Claim 4

A donor sheet useful in pulsed electrical printing, comprising a conductive base sheet having a microcavernous surface with pits or valleys of about 0.5-50 microns across and 0.5-50 microns deep and ridges and peaks of about 0.5-50 microns across and 0.5-50 microns high, and print particles having a conductivity at least that of a semi-conductor lying in irregular mounds and towers on said surface, said particles being about 0.25-15 microns across and present in quantity sufficient to effect printing by transfer of particles to an adjacent recipient sheet upon imposition of an electrical pulse of about 500 volts for two microseconds, said donor sheet having a lateral surface D.C. resistivity less than 100,000 ohms per square.

### Claim 5 (depends on 4)

A donor sheet as defined by claim 4 wherein the microcavernous surface of the base sheet presents a total surface at least 1.4 times its projected area which is based on squaring the linear measurements of the actual surface outline and of its projection.

### Claim 6 (depends on 4)

A donor sheet as defined by claim 4 wherein the base sheet surface comprises particles of filler 1-175 microns across embedded in a resin, said resin being between 5 and 60 percent by weight of the total resin plus filler, the resin with embedded filler being covered by a thin metallic coating.

### Claim 7 (depends on 4)

A donor sheet as defined by claim 4 wherein the base sheet consists of a metallic layer which has been made microcavernous through etching.

### Claim 8 (depends on 4)

A donor sheet as defined by claim 4 wherein the base sheet is metallic and has a metal coating plated thereon, said coating being microcavernous.

### Claim 9 (depends on 4)

A donor sheet as defined by claim 4 wherein the print particles each contain magnetizable material.

### Claim 10 (depends on 9)

A donor sheet as defined by claim 9 wherein the magnetizable material is iron oxide.

### Claim 11 (depends on 9)

A donor sheet as defined by claim 9 wherein the base sheet contains magnetizable material.

### Claim 12 (depends on 9)

A donor sheet as defined by claim 9 wherein the particles have been arranged in mounds and towers through the combined action of friction and magnetic fields at a magnetic inking station.

### Claim 13 (depends on 12)

A donor sheet as defined by claim 12 wherein the base sheet contains magnetizable material.