US 3581257 A
Description (OCR text may contain errors)
United States Patent Inventor Edmund F. Priessnetz Baldwin, N.Y. Appl No. 872,238 Filed Oct. 29, 1969 Patented May 25, 1971 Assignee Electronic Transmission Systems, Inc.,
New York, N.Y.
MAGNETIC HOLDING DRUM 7 Claims, 4 Drawing Figs.
11.8. CI 335/285, 1 01/3 82 Int. Cl Hillf 7/20 Field of Search 335/285,
306; 248/206 (A); 101/382 (MV)  References Cited UNITED STATES PATENTS 3,039,389 6/1962 Meese et al l0l/382(MV) 3,353,481 11/1967 Antonucci lOl/382(MV) Primary ExaminerG. Harris Attorney-Allison C. Collard ABSTRACT: A magnetic holding drum particularly suitable for optical reproduction devices such as facsimile transmit ters, which enables the copy to be held substantially flat over the surface of the drum while the drum is either rotated or optically scanned. The drum includes a plurality of spaced-apart, radially disposed elongated magnets on its cylindrical surface. A sliding holder which is slidably retained in grooves at each end of the drum ismagnetically affixed at any desired position on the surface of the drum in order to maintain the copy flattened against the drums surface. 7
PATENTED M25 1971 INVENTOR. EDMUND F. PRIESSNETZ m.- Q m ATTORNEY MAGNETIC HOLDING DRUM This invention relates to a magnetic holding drum for use with optical reproducing apparatus for maintaining a copy substantially flat on the surface of the drum.
More specifically, this invention relates to a magnetic holding drum having a plurality of radially spaced-apart elongated magnets disposed on the drums surface for magnetically securing the copy material substantially flat on the surface of the drum.
ln reproducing apparatus and particularly those utilized for facsimile transmission, a drum is commonly provided for holding and maintaining the copy material for optical scanning. ln facsimile transmitters, where the drum which holds the copy material is rotated at high speed while it is viewed by an optical scanning device, it is important that the copy material be maintained substantially flat against the surface of the drum in order to prevent distortion of the reproduced copy. Conventional drums are generally provided with mechanical fastening devices which are designed to engage the copy at each end and retain it on the drum surface. For drums which rotate at high speeds in front of optical scanning devices, these conventional mechanical fasteners often become either partially or totally disengaged from the copy material so as to cause its information surface to depart from the surface of the drum, thereby causing distortion of the subsequently reproduced copy on the facsimile receiver. Attempts to overcome these difficulties so as to maintain the copy material more rigidly on the surface of the drum have resulted in complicating the mechanical holding fasteners, and making it more difficult to quickly change the copy material on the drums surface.
Accordingly, the present invention provides an improved holding drum which utilizes magnetic means coupled to the fastening devices in order to secure the copy material substantially flat on the drums surface. The surface of the drum according to the invention is provided with axially spaced-apart magnetic strips which are embedded into the cylindrical surface of the drum. On one segment of the drums surface is disposed a hinged or pivoted clamp for gripping the leading edge of the copy material. The clamp is magnetically held in its closed position against the paper copy by the surface magnets. The end flanges of the drum are provided with a track which engages a sliding element constructed from a flat paramagnetic material which is utilized to flatten the copy against the drums surface. As the sliding element is advanced toward the trailing edge of the copy material, it will be magnetically retained in place and drawn against the copy surface. The magnetic force applied to the paramagnetic sliding element is sufficient to prevent the sliding element or copy material from changing position during the high speed rotation of the drum. Furthermore, no additional fastening devices are required to lock the slider in place or secure the copy to the drums surface. Moreover, when the sliding element is moved over the surface of the copy material toward its trailing edge, it serves to flatten and press the copy material against the drums surface so as to remove any uneven portions thereof.
After the copy material has been reproduced, it can be easily and quickly removed from the surface of the magnetic drum by merely moving the sliding element away from the copy surface and opening the hinged or pivotably mounted clamp away from the leading edge. This will interrupt the magnetic engagement on the paper clamp.
It is therefore an object according to the present invention to provide a magnetic holding device capable of retaining copy material substantially flat against the surface of the drum.
It is another object according to the present invention to provide a magnetic holding drum which includes a plurality of magnetic strips embedded in its surface for retaining the copy material.
It is still a further object according to the present invention to provide a magnetic holding device which is simple in design, easy to construct, and reliable in operation.
Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawing which discloses one embodiment of the invention. It is to be understood, however, that the drawing is designed for the purpose of illustration only and not as a definition of the invention.
In the drawing, wherein similar reference characters denote similar elements throughout the several views:
FIG. 1 is a perspective view of the magnetic holding device according to the invention;
FIG. 2 is a cross-sectional view taken along section 2-2 of FIG. 1;
FIG. 3 is a further cross-sectional view taken along section 3-3 of FIG. 1; and
FIG. 4 is a still further cross-sectional view taken along section 4-4 of FIG. 1.
Referring to FIGS. 14 there is shown the magnetic holding drum 1 including end flanges 12 and 17, pivotably mounted on shaft 11. Across the cylindrical surface of drum 10 is disposed a gripper or clamp 13 which includes hinge pieces 23 secured to each end. Hinge pieces 23 include a shaft 24 which projects through corresponding bores in end flanges 12 and 17. Clamp 13 includes a pair of handles 18 secured at each end to permit the easy raising and lowering of the catch over the leading edge of copy material 14. Disposed around the cylindrical surface 21 of drum 10 are a plurality of permanent magnets 22 constructed from thin strips of magnetic material which are secured in spaced-apart positions on the drum surface extending generally parallel to the axis of shaft 11. Magnetic strips 22 may also be spirally wound around drum surface 21 or assume any other configuration.
Disposed on drum 21 is also a sliding element 15, having its end portions slidably inserted into circular tracts 20 which are contained on the internal sides near the rims of end flanges 12 and 17. Sliding element 15 also includes a handle or finger grip 16 secured to its top surface, so that it may be easily moved over drum surface 21 and copy material 14 to flatten the copy material against the drum surface. As sliding element 15 approaches the end of copy material 14, as shown in detail in FIG. 4, it can be retained in place by the attraction of one magnetic strips 22 closest to the end of the copy material. No further securement of sliding element 15 will be required. Clamp or gripper 13 is also retained in its closed position by another one of magnetic strips 22 so that it will not release the leading edge of the paper during the movement of the drum surface. Both sliding element 15 and clamp 13 are constructed from a paramagnetic material such as steel, nickel, etc., so as to cooperate with magnets 22. Drum surface 21 is preferably constructed from a nonmagnetic material, such as aluminum, so as not to interfere with the magnetic attracting forces of strips 22. End flanges '12 and 17 are secured to the end of drum 10 by means of fastening screws 19 and are also preferably constructed from a metal or rigid material sufficient to support drum surface 12 on shaft 11. Copy material 14 will generally consist of paper or a flexible sheet material containing information. Magnetic strips 22 may be permanent magnets, or electromagnets.
While only a single embodiment of the invention has been shown and described, it will be understood that many modifi cations and changes may be made thereunto without departing from the spirit and scope of the invention.
What I claim is:
1. A device for holding a copy material comprising:
a drum having a substantially cylindrical surface,
clamp means for retaining one edge of said copy material,
sliding means for retaining the other edge of said copy material, and,
magnetic means secured to said drum surface for magnetically engaging said clamp means to said drum surface.
2. The device as recited in claim 1, wherein said magnetic means comprises at least one magnetic strip disposed within the surface of said drum and substantially parallel to its axis.
means and said sliding element are constructed from paramagnetic material, and said magnetic strip is disposed for magnetic engagement with said sliding means.
6. The device as recited in claim 1, wherein said magnetic means comprises a plurality of permanent magnet strips embedded in said drum surface.
7. The device as recited in claim 6, wherein said drum surface is constructed from a nonmagnetic material.