US3477368A

US3477368A - Printing apparatus employing magnetic transfer band in which image impressions can be made

Info

Publication number: US3477368A
Application number: US677594A
Authority: US
Inventors: David B Spaulding
Original assignee: Deutsche ITT Industries GmbH
Current assignee: TDK Micronas GmbH; ITT Inc
Priority date: 1967-10-24
Filing date: 1967-10-24
Publication date: 1969-11-11
Anticipated expiration: 1986-11-11
Also published as: FR1589900A; DE1804873A1; GB1238210A; NL6815243A

Description

' NOY. 11,1969 I D B sPAuLDlNG I H 3,477,368

PRINTING APPARATUSEMPLOYING MAGNETIC TRANSFER BAND IN WHICH IMAGE IMPRESSIONS CAN BE MADE Filed Oct. 24, 1967 3 Sheets-Sheet 1 I I 8 T /agz [e wipl I revsuron NW0 8. SAAUlO/NG a ATTORNEY Nov. 11. 1 969 D B. SPAULDING 3,477,363

LOYING MAGNETIC TRANSFER BAND PRINTING APPARATUS EMP IN W ICH IMAGE IMPRESSIONS CAN BE MADE Filed Oct. 24, 1967 INVENTOR DAV/0 8. PAUL O/NG 24.1%

ATTORNEY Nov.ll, 1969 D SPAULDING 3,477,368

PRINTING APPARATUS EMPLOYING MAGNETIC TRANSFER BAND IN WHICH IMAGE IMPRESSIONS CAN BE MADE] Filed Oct. 24, 1967 3 Sheets-Sheet 3 v mvsm'oa 4 DAVID A. SPAULO/NG ATTORNEY United States Patent 3,477,368 PRINTING APPARATUS EMPLOYING MAGNETIC TRANSFER BAND IN WHICH IMAGE IMPRES- SIONS CAN BE MADE David B. Spaulding, Carlisle, Mass., assignor to International Telephone and Telegraph Corporation, a corporation of Delaware Filed Oct. 24, 1967, Ser. No. 677,594 Int. Cl. B41m /20 U.S. Cl. 101-150 4 Claims ABSTRACT OF THE DISCLOSURE An arrangement is provided for forming a transferable pattern on a continuously moving transfer band and for transferring said pattern across an air gap to a transversely moving record surface.

BACKGROUND OF THE INVENTION In general this invention relates to printing apparatus comprising an endles transfer band, an image forming station, and a transfer station, and in particular to a transfer band moving transversely with respect to a recording surface, such that the transfer of the pattern to the recording surface is accomplished across an air gap.

The prior art shows various combinations of marking stations, transfer bands, and transfer stations, however, the distinction between these and the embodiments according to the invention are in the type of transfer band used, the particular kind of ink used in conjunction with a particular band, the manner in which the ink characters are formed, and the manner in which the characters are transferred to the record copy.

In all the prior art, the problem of smearing of the inked image on a band moving transversely with the copy paper is neither recognized nor is there a solution proposed. Therefore, the apparatus provided by this invention solves this and other problems inherent in the prior art, namely, there is a distinct advantage in electrostatic or magnetic transfer of an image across an air gap when the transfer band is moving transversely to the direction of the record copy.

SUMMARY OF THE INVENTION It is an object of this invention to provide means for forming a transferable pattern and to transfer that pattern from a transfer band to a transversely moving record sheet.

According to the broader aspects of the invention there is provided a moving transfer band, means for forming a transferable pattern on said band, means movable in a direction transverse to said band for receiving said pattern across an air gap, and means for electrostatically or magnetically transferring said pattern from said band across said gap to said receiving means.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more clearly understood by reference to the accompanying drawings in which:

FIGURE 1 shows an embodiment according to the invention;

FIGURE 2 is an embodiment of the image forming station of FIGURE 1, and FIGURE 2A is enlarged view of the transfer station according to FIGURE 1;

FIGURE 3 is another embodiment of the invention;

FIGURE 4 is one embodiment of the image forming station of FIGURE 3;

FIGURE 5 is another embodiment of the image forming station of FIGURE 3; and

Patented Nov. 11, 1969 FIGURE 6 is another embodiment of the image forming station of FIGURE 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGURE 1, one embodiment of the invention is shown in which a continuously moving transfer band 11 is supported on rollers 12, one or both of which may be powered to provide the motion 12a of the endless band 11. The band 11 passes but does not touch a stationary image forming station 13 consisting, as shown in FIGURE 2, of a row of fluid expulsion nozzles 14 capable of depositing discrete fluid droplets 15 on the moving transfer band 11, in response to electrical or other suitable energy pulse commands 16. The image forming station 13 and band 11 are configured so as to permit the formation of any image 17 in the form of twodimensional array of individual fluid. droplets on the moving transfer hand without subsequent running together of the droplets and destruction of the image.

The images having been so formed are transported by the moving band pass the copy paper 18, movable in direction 18a, and when a particular group of droplets forming an image to be printed are opposite the location of the copy paper area where printing is desired, an attractive field force generator transfer station 19, located directly behind the paper, is excited and the image 17 is rapidly transferred across the air gap between the moving band and the copy paper surface as indicated in FIG- URE 2A.

The fluid droplets 15 used in forming the images 17 is ink of suitable composition such that the capillary adhesive force tending to hold the deposited droplets upon the band surface can be overcome when printing is desired by the attractive force field created at the transfer station 19 during the time of actual printing. Images formed on the band are therefore maintained during the interval separating formation and removal of the ink droplets 15.

Printing of the image on the copy paper is achieved when the uninterrupted transfer band 11 movement locates the image array 17 of ink droplets 15 opposite the desired location on the copy paper 18. The appropriate electrostatic field of transfer station 19 located in close proximity to the copy paper 18 is excited by some automatic means for a short duration to cause the ink droplets 15 to be attracted to the copy paper surface. The attractive electrostatic force may be created by generating the required voltage gradient to induce an opposite charge in the droplets, or by utilizing a precharge by any conventional technique, such aspassing them through an electric arc corona discharge or maintaining the entire band at an electrical potential with a power supply.

Another embodiment of the principle of this invention is shown in FIGURE 3, in which the continuously moving transfer band 11 is again supported on the rollers 12. The band passes through the image forming station 13 which is comprised of a band conditioner 21, an image impression maker 22 and a fluid coater 23. The basic process provided by these items consist in making an image shaped array of holes or depressions in a nonwettable band surface such that when a roller or spray of fluid is introduced to the surface, only those holes or depressions so formed by the impression maker 22 will attract and withdraw from the fluid source a discrete array of droplets forming the image to be printed. Since the band 11 is endless, a band conditioner 21 is located before the above described operations in order to restore an unmarked even surface of nonwettable material for presentation to the image impression maker 22.

The image forming station 13 and band 11 are arranged to permit fromation of any image in the form of a two dimensional array 17 of individual fluid droplets on the moving transfer band 11 without running together of the droplets and destruction of the image. The images having been so formed are transported by the moving band past the copy paper 18. When a particular group of droplets forming an image to be printed are opposite the location on the copy paper 18 where the printing is desired, and attractive field force generator transfer station 19 located behind the paper is excited and the image is rapidly transfered across an air gap from the moving band to the copy paper surface.

FIGURE 4 illustrates one embodiment of FIG. 3 in greater detail, the roller band conditioner 21 applies a nonwettable material 25 to fill the empty impressions 26 in the coating on the band 11': Impression maker 22 creates the new impressions 27 in the nonwettable material 25, so that the fiuid coated roller 23 by virtue of the fluid coating 28 may fill the empty impressions 27 with fluid droplets 24. The function of the image impression maker 22 may be accomplished by any of several acceptable means. A row of needle point electrodes may be charged in a selective manner in response to command signals to cause an electrical arc to rupture the nonwettable coating 25 and form the desired depressions or holes 27 in the surface, A row of air jet nozzles may similarly be used to blast, as shown in FIGURE 4, discrete depressions or holes in the surface, or a slightly different technique may be used where, rather than having a band conditioner impression maker, a row of miniature fluid expulsion nozzles would deposit a negative of the image to be formed of nonwettable fluid upon a previously cleaned band surface. The negative so formed need not remain in liquid form, but could be solidified upon deposit on the band so that the ultimate cleaning is accomplished by reheating to effect removal.

The fluid 24 employed in the embodiment shown in FIGURE 4 is a magnetic ink. It is a suspended solution of .iron particles in a highly colored solvent, or other suitable composition. The transfer band 11' would therefore be fabricated of a suitable material to form a permanent flexible magnet with north and south poles 29 located on opposite flat sides of the band. The ink droplets 24 de posited on the band 11' at the image forming station are then held securely in place by the magnetic force exerted on each droplet, in order to maintain the image integrity during the time interval separating image formation and removal.

Printing of the image 17 on the copy paper 18 is achieved when the transfer band movement locates the array of ink droplets 24 opposite the desired location on the copy paper. The appropriate electrostatic or magnetic field transfer station 19, located in close proximity to the copy paper, is excited by some automatic means exerting an attractive force on the ink droplets suflicient to overcome the magnetic force holding the image to the magnetic transfer band 11 and rapidly attract the image to the copy paper surface. This operation takes place without interrupting the movement of the transfer band, the excitation of the attractive field being of a rapid pulse nature. The use of an electrostatic force to effect the printing process may be enhanced by imparting a specific static charge, opposite in sign to the field used for printing, to the ink droplets after formation at the image forming station. This may be accomplished by any of the several conventional means such as passing the ink droplets through a charge stat-ion consisting of an electrical corona discharge after deposit on the transfer band or by maintaining the entire band at a constant electrical voltage by means of an appropriate power supply.

The use of a magnetic or electrostatic force field for printing also permits the use of a nonmagnetic material for the transfer band if a permanent magnetic forming a stationary member is located adjacent the band surface opposite to the surface on which the droplets are deposited.

Referring now to FIGURE 5, another embodiment similar to the arrangement shown in FIGURE 4 is illustrated. The arrangement in FIGURE 5 is the same as the arrangement in FIGURE 4 except that the transfer band 11 is not magnetic and the fluid employed with roller 23 is not a magnetic ink. The fluid 30 used in this embodiment is an ink of suitable composition so that the capillary adhesive force holds the deposited droplets 31 within the impression openings 32. This capillary adhesive force can be overcome when printing is desired by the attractive force field created at the time of the actual printing as described in connection with FIGURE 3. The images formed on the band are therefore held and maintained during the interval separating formation and removal of the ink droplets 31 by the capillary force.

Referring now to FIGURE 6, another embodiment of the image forming station of FIGURE 1 is shown whereby, the image is created by an array of small discrete magnetized areas 33 on a magnetizable band 11". A row of electromagnets 34 may be formed so as to create any combination of individual magnetized areas 33 in response to the energizing signals 37. An applicator 38 employing a magnetic fluid ink 39 will roll the nonwettable band 11" containing the magnetic image. The magnetic ink will cause the formation of the two-dimensional area image since fluid will be attracted toward and held at the magnetized areas 33 as individual droplets 40. The ink droplets 40 deposited on the band at the image forming station are thereby held securely in place by the magnetic force exerted on each droplet maintaining the image integrity during the time interval separating image information and removal at the transfer station.

It should be evident to those skilled in the art, that the foregoing embodiments may be adapted to use a dry ink, wherein the dry ink is electrostatic and the transfer band is an electrostatically changeable transfer band, such that the electrostatic dry ink is retained selectively on said band by electrostatic force until overcome by the magnetic field or electrostatic force at said transfer station.

In addition, it is possible to use a dry magnetic ink in combination with a magnetic transfer band, so that the magnetic ink is selectively retained on the band by magnetic attraction until overcome by the magnetic field or electrostatic force at the transfer station.

I claim:

1. Printing apparatus comprising:

a continuously moving magnetic transfer band havin a non-wettable surface thereon; an impression maker for forming impressions in said surface;

means for depositing magnetic ink fluid droplets in said irnpresions;

means for moving a record along a path in a direction transverse to the movement of said band, said record path being spaced from said band by an air gap;

a transfer station adjacent said path including means for magnetic transfer of said ink pattern from the band across said gap onto the record; and

a band conditioner for removing the impressions in said surface and permitting reuse of said band in a continuous loop.

2. Apparatus according to claim 1, wherein said impression forms an image array in said non-wettable band surface by said image impression maker so that when a roller of magnetic fluid contacts the surface, only those impressions formed will attract and withdraw from the fluid roller source, the array of fluid droplets forming the image to be printed.

3. Printing apparatus comprising:

a continuously moving magnetic transfer band formed in a loop and having a non-wettable surface theeron for receiving a transfer-able ink patternf an impression maker for causing desired impressions in said surface;

means for causing magnetic ink fluid droplets to be deposited in said impressions;

5 6 means for moving a record along a path in a direction References Cited transverse to the movement of said band, said record path being spaced from said band by an air gap; UNITED STATES PATENTS a transfer station adjacent said path including means 2,841,461 7/1958 Gleason XR for magnetic transfer of said magnetic ink droplets 3/1961 Burkhardt 101-414 from the band across said gap onto the record; and 5 2,985,135 5/ 1961 m means for reconditioning said band by removing the 3,194,674 7/ 1955 Sakufalimpressions in said surface and permitting reuse of 3,211,088 1965 Naiman 101-114 said band, 3,279,367 10/1966 BIOWIEI. 4. Apparatus according to claim 3, wherein said im- 3,299,809 1/ 967 JavOnk et a1.

pressions form an image array in said non-wettable band 10 3,377,598 4/1963 surface by said image impression maker so that when a roller of magnetic fluid contacts the surface, only those EDGAR BURR Primary Exa'mmer impressions formed will attract and withdraw from the U S Cl XR fluid roller source the array of fluid droplets forming the 15 101 1 170 197 1 image to be printed, and the droplets are retained in the impressed areas by the magnetic force of said band until overcome by the magnetic field at said transfer station.