US2413400A - Facsimile apparatus - Google Patents

Description

FACSIMILE APPARATUS Filed July 14, 1942 ATTORNEY Patented Dec. 31, 1946 2,413,400 FACSIMILE APPARATUS Charles J. Yeung, Ardmore, Pa., assigner to Radio Corporation of America, a corporation of Dela- Ware Application July 14,1942, Serial No. 450,856

Claims. (Cl. 178-7.1)

This invention relates to facsimile apparatus and particularly to a transmitter form of device.

Generally speaking, this invention is directed to a form of facsimile apparatus in which provision is made for centering'the optical scanning system relative to the record supporting surface, and-at the same time positioning the record support surface xedly relative to the scanning instrumentality.

Broadly speaking, the form of apparatus herein disclosed is related to the type of facsimile sy..- tem set forth and described in my co-pending ap plication Serial No. 440,923, led April 29, 1942, now U. S. Patent No. 2,394,649, 4granted February l2, 1945, which discloses the general form of drive mechanism by which the scanning instrumentality is moved relative to the record holder to provide for the scanning of the subject of which the image is to be transmitted. Also, this invention is directed to the same general type of apparatus as that disclosed in my application filed concurrently herewith,`which application relates primarily to the manner in which the record subject is held in fixed position relative to the record support surface.

In its preferred form, the apparatus for transmitting the pictures comprises a scanning instrumentality which rotates relative to a record support, and during the course of its rotation moves longitudinally of the record support, so that the subject carried by the record support is scanned to produce signal outputs representative thereof. The apparatus for accomplishing this result consists essentially of a frame or support member upon which is mounted a movable scanning instrumentality which comprises a scanning head adapted to rotate relative to the record support, a drive motor and suitable gear `bor; for rotating the scanning head relative to the record support and, at the same time, providing a suitable drive for moving the scanning head and complete drive assembly longitudinally of the record support for the purpose of scanning the record. and lastly, a photocell and amplifier combination which is energized in accordance With the light reflected through the scanning head so that the desired signal outputs are developed.

My co-pending application Serial No. 440,923, filed April 29, 1942, now U. S. Patent No, 2,394,649,

granted February l2, 1946, discloses and claims the method by which the complete assembly of the motor, the gear box, the scanning head and the amplifier is rotated and moved relative to the record support surface.

The present application is concerned primarily with the method and system for positioning the scanning elements relative to the record support, so that improved copies may be produced. `In one of its forms, the present apparatus comprises a record support surface which is formed of a transparent plastic material such as that known in the art by the trade names of Lucite or Crystallite. This record support is preferably formed as a half cylinder with the circumferential path thereof approximately equal to the length of one scanning line of the picture.

Because of the fact that plastics of this nature are somewhat of a non-rigid character unless properly supported, and because of the fact that the thickness of the material varies considerably under manufacturing tolerances, it is essential that the record supporting material be located very accurately relative'to the optical system used for scanning. For this purpose, the supporting frame of the machine is formed so that each end is accurately machined to a circular formation, which is e, true circle having a. total circumference equal to two scanning lines. The plastic material Which is to form the record support drum is to be braced against these rigid circular supports and securely clamped thereto from either end, so that the end portions are accurately shaped to a cire cular path and secured in such position, with the result that the plastic retains proper curvature throughout its length.

Next, the invention herein to be set forth is particularly concerned with suitable means for supporting the traveling optical system and itsv associated drive in such a manner that the optical system in its rotation shall be accurately alined and positioned relative to the outer surface of the plastic record support upon which the record subject for transmission is to be carried. Also, in the disclosed apparatus, provision Will be made Whereby independent adjustments of such an optical system may be made at each end of the plastic support.

It accordingly becomes one of the objects of the present invention to provide Ways and means for overcoming one or more of the defects of the prior art systems concerned 'with facsimile apparatus through the reduction of both size yand Weight of the equipment.

It also becomes one of the objects of the present invention to provide a. suitable record support surface for carrying a subject of which the image is to be transmitted, which support surface shall not have the objections of prior art arrangements which use glass and which, because of the nature of the support, veryfrequently include bubblesor striations which tend to reduce the quality' of picture transmission.

Furthermore, it is an object of the present invention to provide a record support surface which shall avoid the objections of prior art arrangements using plate glass, which necessitated eX- tremely careful bending of the glass and frequent breakage, or the very accurate grinding of a glass cylinder inside and out, which is almost prohibitive in such types of arrangements, due to excessive costs and the great danger of breakage which might, in some cases, necessitate complete interruption of the service of transmission. A further object of the invention is to provide a convenient means for centering the optical system so that in its course of rotation, a light beam directed from the optical system through the transparent record support surface to the record and then back through the transparent record support surface to the scanning head optical system, and thence to the photocell, shall at all times be of equal length irrespective of the actual angular position of the scanning head re1- ative to the support. It becomes essential that this optical path be retained of consta-nt length because of the lenses necessarily used in connection with such apparatus, and, accordingly, a slight variance from a centermost position of the optical system relative to the record support and the supported record will vary to a very substantial extent the relative picture detail obtainable, because eccentricity of the optical system will produce a defocused scanning spot upon the record.

A further object is that of providing ways and means for mounting a plastic record support surface so that it may be easily replaced if scratched or worn, without making necessary a complete readjustment of the optical line-up and adjustment of the scanner.

Other objects and advantages of the present invention will of course become apparent and immediately suggest themselves to those skilled in the art to which the invention is directed from a reading of the following specification in connection with the accompanying drawing which shows, in perspective and partly in section. one of the suitable forms of such apparatus.

Referring now to the drawing, the supporting frame II comprises a circular upper section I3 and a rectangular lower section I5. The upper curved section i3 is divided into two separate end portions which are carried from the lower rectangular base support I5. The centermost part of the semi-circular upper support member or section I3 is notched at IT, and into these notched portions a cover section I9 (shown only in part) is adapted to rest. The coverl section per se, and the manner of supporting the same relative to the complete assembly is set forth more particularly and claimed in my co-pending application filed concurrently herewith.

The ends of the upper semi-circular Section I3 have, at their innermost portions, a ring-like section 2! which has its edge portion 23 very accurat-ely machined to circular contour, and against this circular contour the transparent record support surface 2'5 is adapted to be placed and secured by means of ring members 21, as will hereinafter be more fully explained. These ring members, located at either end of the support, function as a sort of inside expansion clamp positioned within the ends of the supported member to hold it securely.

The rectangular base support members.. I

carry, on one side, a channel section 29 which is adjustable in the direction shown by the arrows up and down, and which may be secured in any desired fixed position by means of suitable nuts clamping on the bolts 3 I Along one edge 39 of the channel 29 there is supported a grooved sliding member 35 which supports one side of a supporting housing 31 which is for the purpose of carrying and supporting the driving motor 39 for the complete assembly, the gear box GI for rotating the scanning head 43 from the drive motor, and also for driving suitable gearing, later to be explained. Also, the support 3'.' is adapted to support and carry the amplifier and photocell combination, schematically shown at 45, all of which elements are arranged to slide and move longitudinally of the record support surface 25, in the direction shown by the arrows, and at the same time to move internally of the record support member 25.

The weight of the motor 39, the gear box 4I, the scanning head 43 and the photocell and amplifier combination 45 and the associated gearing is also supported from slidable link support members il and 48 which are carried upon a shaft 49 which is, in turn, supported in the lower housing section I5. The lower end of the link support members 4l and 48 are formed as bearing surfaces 59 and 52, while the upper portion of these link members is adapted to support either end of the drive spindle 5I. The link support members il and 49 are supported intermediate the bearing surfaces 59 and 52 through which the shaft 49 passes and the upper portion which supports the spindle 5I, so that these links are rigid with respect to the supporting frame for the scanning head assembly.

As was explained in my co-pending application Serial No. 440,923, led April 29, 1942, now U. S. Patent No. 2,394,649, granted February 12, 1946, a spindle 53 is adapted to be held in the frame support sections I5', and, by motion of the lever arm 55 (only partially shown since it is shown in my co-pending application Serial No. 440,923, filed April 29, 1942), now U. S. Patent No. 2,394,649, granted February 12, 1946, the spindle 53 is adapted to be rotated to a slight extent in the direction shown by the arrows adjacent it, so as to bring the movable half nut 5l into and out of engagement with the threads 58 on the drive spindle 5I. As is evident from the drawing, engagement of the half nut 57 with the threads 53 on the drive spindle 5I will tend to cause the link support members III and 48 to move longitudinally of the support shaft 49 and to move the complete supported assembly in the same direction, so that sliding contact is also maintained by the slotted member 35 being supported by the edge 33 of the Lshaped member 29.

For the purpose cf rotating the drive spindle 5I, the motor 39 is energized (from `a source not shown), and, through suitable gearing (not shown) causes the scanning head 43 to rotate about the shaft 6i as an axis. Similarly driven from the same motor source, the shaft or spindle 93 carrying the worm 65 is adapted to turn the pinion Gi which is keyed to the drive spindle 5l. The result is that when the half nut 5l is made to engage the threads 53 of the drive spindle 5I, the rotating motor causes the complete assembly of the motor, the gear box, the scanning head and the photocell and amplifier combination to move internally of the support 25. This arrangement, it is thus evident, is one in which the lead ment of the half nut 5'! which is carried upon the frame member proper.

The scanning head, it will be seen, comprises a plurality of conically shaped members 99 and 69 with a suitable optical system 'll arranged todirect light from a source (not shown) within the scanning head outwardly toward the support surface 25, and then backward through the scanning head and, by appropriately chosen means,` into the photocell and amplier combination, all

as explained in my co-pending application Serial No. 440,923, led April 29, 1942, now U. S. Patent No. 2,394,649, granted February 12, 1946.

When the light passing out of the optical system H to the subject for transmission which is supported upon the transparent Vsupport is reflected, it is reflected internally of the conical member B9 and thence, by a reecting member notlshown, but shown in application Serial No. 440,923, filed April 29, 1942, no-w U. S. Patent No. 2,394,649, granted February 12, 1946, it is arranged to vary the photo emission of a photocell contained within the photocell and amplier combination 45. Thus there is produced a vari ance of output from the amplier which is proportional to the intensity of light and shadow on the record surface. If, however, the optical systemis not accurately positioned relative to the record support member 25 and if it is not so alined. that the length of optical path from the light source to the subject and thence back to the photoelectric cell is always identical, the effects of defocusing will be apparent and adequate sharpness will not be present in the transmitted and received pictures or facsimiles.

Accordingly, to provide adjustment of the scanning head so that it shall be properly centered relative to the record support 25, the end bearing members i3 and 'i5 for the shaft 49 are formed as eccentrics 'Vl and 119, and the eccentricity may be varied by means of rotation of the bearing surfaces il and i9 relative tothe main bearing members 'i3 and l5 by means of a slotlike member 8l for the eccentric bearing l1 which is capable of being turned. A similar member is provided for the eccentric bearing. I9 but is not shown in the drawing.

When the bearing surface 'il is rotated, it isl apparent that the shaft 49 and the link members are moved transversely in accordance with the variance in eccentricity of the variant, andbef cause the link members are formed as a rigid part of the housing support for the drive means, the scanning head and the photocell and amplier'combination it is apparent that the entire assembly may be laterally shifted by the rotation of the eccentrics.

In order to provide so that the optical path shall always be of equal length, the assembly, when rst set up, is so arranged that the scanning head member is turned relative to the semicircular support ring, and particularly the accun rately machined edge 23 thereof, so that the cone member 69, for instance, comes opposite a point generally designated as A on the accurately machined member, and the spa-cial separation between the optical system ll and this point A is then measured. It is, of course, appreciated that under such circumstances the transparent support 'surface 25 has not yet been positioned, and the clamping ring 27 is of course also miss- 6 ing. through 180 yand the spacial separation between the optical system 'Il and a point on the ring member 23 diametrically opposite the point A is carefully measured as to its spacing from the said optical system. Generally speaking, this last named point would correspond closely to that point designated as B on the drawing, although it is to be understood that because of the portion of the drawing broken away, the actual point B which is used for alinement cannot be shown. If there is a difference in the spacing of the optical system under such conditions from points A and B, then the eccentrics are adjusted until equal distance spacing is provided, or, in other words, the distance from the center of rotation to each of points A and a diametrically opposite point (considered as B for illustrative purposes) is equal. t Under such circumstances, it can be appreciated that the spacing from the center of the shaft El to the machined edge 23 at points A and B represents the true desired radius which must be obtained for all, angles of rotation.

However, it is next necessary to adjust the length of the optical path at intermediate locations, and, accordingly, at a point such as that shown by point P for instance, a measurement is again taken and the eccentric il is adjusted in position so that there shall be the same spacial 'separation between the optical element 'H and the point P as there was between the optical element and points A or B when the scanning head was in horizontalposition. The point P is chosen as corresponding to that formed by a line assumed to be drawn between the center of the shaft 49 and the center of the shaft 6| upon which the optical system rotates as its axis. This makes the distance between the center of rotation 6I and point P equal to that previously found for the distance between point 5l and either A or B, but it would result in making the distances between point 6I and A and B no longer equal.

Next, the optical system of the scanning head is turned throughout a angle to the point tween the end of the optical system 'H and the point P,` it is apparent that an adjustment must now bemade in this new direction. This last named adjustment is accomplished by moving the channel section 29 on which the support 3l is adapted to slide by virtue of the supported sliding member 35 up or down in the directionsv shown by the arrows by loosening the nuts on the bolts 3|; and, this adjustment is made until the spacial Vseparation between the optical elements 'H and the point 90 removed from the point P shall be equal to the spacial separation between the optical system 'il and the point P.

After the measurements above stated have been made at one end of the support, the complete scanning head assembly is moved to the opposite end of the support, so that the scanning head would be arranged Vto scan a supported subject at the right hand edge of the record support 25 (assuming it were in position), and adjustments and measurements corresponding exactly to those abo-ve explained are repeated by adjusting, for instance, the eccentric 'I9 and then the positioning of the right hand end of the channel section. Then the adjustment is4 checked `at *the Then the scanning head 43 is .rotated rst end, and, when accurately established, it will be found that further adjustment is unnecessary.

Now, to position the record support surface 25 with regard to the remainder of the support, this element is placed in position, as indicated by the drawing, until one edge B3 thereof comes between the vertical edge of lthe clamp member S5 and the edges ill@ of the frame support, and of course the outer surface of the record support 25 is caused, at its ends, to bear up against the accurately machined semi-circular portion E3 of the main sup-port.

It was above explained that the support member 25 is preferably of a plastic type and since plastics, as a general class, are usually subject to cold ilo-w, as well as thermal distortion, the support means herein described is for the purpose of correctly shaping the plastic material when it is installed and then for maintaining such shaping.

Next, the outer edge or face of the plastic member 25 is caused topress up against the machined semi-circular section 23 and the ring member 2l is secured by the clinch plate 8l, which has an L-shaped outer support capable of holding both the ring member 2l and the support 25, and when these members are tightly pressed against the machined semi-circular edge 23, the support will be properly positioned. A clinch plate 8l, also not shown, is positioned diametrically opposite that one already indicated. From the above, it will be appreciated that these plates exert no circumferential force on the support 25 but serve to hold the edges thereof in an outward direction against the edges lil of the `frame member i5, which edges lll have been made straight'l and true and flush at their ends with the surfaces 23.

At the opposite end of the support frame a similar ring member 2 is positioned to hold the opposite end of the record support 25. It thus becomes obvious that with the scanning head assembly having already been adjusted in its position relative to the carefully machined semicircular edge 23 and the record support surface 25 rigidly positioned relative to this same surface, the length of the optical path remains invariant when a record subject tl is positioned thereupon.

As is apparent from the drawing, the plastic member 25 need not seat itself'at the bottom of the clinch plate 81, nor yet needit press directly against the upper surface of the clamp 85, but rather it must merely be held between the edge H15 of the tion of the clamp 85. This then provides for the possibility of the plastic member expanding with temperature changes and permits it to move slightly along a circular path relative to its support. It is apparent, of course, that the ccoefcient of expansion of the plastic is greater than that of the metal, and therefore some provision is made for permitting the length of the plastic to change without changing in any way its support or mounting position.

In further consideration of this invention, it has been pointed out above that the plastic member 25 is of substantially semi-cylindrical shape, but it is to be understood, of course, that the plastic support need not necessarily be of semi-cylindrical configuration. If, however, the arcv Subtended by the plastic material be other than the substantially 180 -arc subtended bythe arrangement illustrated by the drawing, vthen it is apparent that the number of scanning frame and the upright sec- L 8 heads must-be changed. If, for instance,` the plastic member were to extend only for then three separate scanning heads would be provided for the scanning device with the spacings thereof bein-g substantially 120. In any case, the plastic member is formed as a surface of revolution and it is so positioned that the outside of the transparent or plastic material is adjacent to a, machined edge and so referenced that when the adjustment of the axis of rotation of the scanning head is made, the length of the optical path shall remain substantially invariant.

Other and further modifications of the invention of course may readily be made, provided the changes fall fairly within the spirit and scope of what has herein been set forth.

What I claim is:

l. Facsimile apparatus comprising a partiallycylindrical transparent record support member, a movable and slidable member, a rotary scanning device, a drive unit for rotating said scanning device, and an amplifier unit for the said scanning `device all carried upon the said slidable member and all positioned internally of the said record support member, means including guide elements for the slidable and movable member for causing the rotary scanning element, its drive element and the associated amplifier all to move longitudinally of and internally of the said partially-cylindrical support member, means for adjusting the center of rotation of the scanning element in each of two directions normal to the direction of longitudinal motion so as to locate the scanner in predetermined positions relative to the partially-cylindrical support member so that the said rotary scanner rotates upon an axis approxi mately corresponding to the center of the curvature of said partially-cylindrical support member.

2. Facsimile apparatus comprising a substantially semi-cylindrical transparent record support member, a rotary scanning device and associated drive positioned internally of the said support member with the scanning device being adapted to rotate upon an axis approximately corresponding to the center of curvature of the semi-cylindrical support member, means including guide elements for causing the rotary scanning element and its drive to move longitudinally of and internally of the said semi-cylindrical support member, means for adjusting the center of rotation of the scanning element relative to the semi-cylindrical support member, said adjusting means comprising -a laterally adjustable means for shifting the said rotary scanning means and its associated drive in a direction which is normal to the direction of motion of the said scanning means during scanning relative to the semi-cylindrical support member, means for moving one of the saidguide elements in a direction which is normal to the direction of motion of the scanning device and its associated drive and also normal to the path of the first said adjustment, whereby rotation of the scanning device is caused to take place about an axis providing equal radiall distances between the scanning device and all points on the semi-cylindrical record support element.

3. Facsimile 4apparatus comprising a transparent record support member formed as a surface of revolution, a rotary scanning device and associated drive positioned internally of the said support member with the scanning device being adapted to rotate about an. axisv approximately corresponding to that of the surface or" revolution, said scanning device including a plurality-` of scanning heads with the number thereof being directly related to the angle subtended by the arc of said surface, means including guide elements for causing the rotary scanning heads and the drive element therefor to move longitudinally of and internally of the said transparent record support member, means for adjusting the center of rotation of the scanning devices relative to the transparent record support member, said adjusting means comprising means for shifting the said rotary scanning means and its associated drive in two directions each normal to each other and each normal to the direction of motion of the scanning head and its drive relative to the transparent record support member.

4. Facsimile apparatus comprising a transparent record support member formed as a surface of revolution and being of substantially equal radius at all points on the surface, a rotary scanning device and associated drive positioned internally of the said support member with the scanning device being adapted to rotate about an axis approximately corresponding to that of the surface of revolution, said scanning device including a plurality of scanning heads of a number equal to 360 divided by the angle subtended by the arc of the transparent support surface, a light source positioned substantially upon the axis of rotation of the scanning device, optical means to direct the light from the source through the scanning heads to the record support member, means including guide elements for causing the rotary scanning device and its drive to move longitudinally of the said transparent support member, means for adjusting the center of rotation of the scanning device relative to the said transparent support member, said adjusting means comprising means for shifting the said rotary scanning device and its associated drive in two directions each perpendicular to each other and each perpendicular to the direction of mo- 10 tion of the scanning device relative to the transparent support member so that the length of the light path from the source to the transparent support remains substantially constant for all angles of rotation of the said scanning device.

5. A facsimile device comprising a rotary scanning element, drive means for rotating said scanning element, and means for moving the scanning element and the rotating drive means therefor along a predetermined limited length longitudinal path during rotation of the scanning element, a frame support for the scanning element and the drive means therefor positioned externally of and so as substantially to surround the said scanning element, said frame support having a partially-cylindrical configuration at each of two extreme positions of longitudinal movement of the scanning element, means for positioning a substantially transparent and elongated record supporting element in such manner as to cause said record element to conform throughout its length substantially to the partially-cylindrical ccnguration of the frame support, said elongated transparent record support element having substantially the same length as the path of longitudinal motion of the scanning element, means for clamping the curved edges of the supported transparent element rigidly against the partially-cylindrical surface of the frame support element so that the curved configuration is established throughout the length of the said element, means for clamping substantially the complete linear edges of the supported transparent member to the frame member and means for adjusting the scanning element and its drive on the supporting frame element so as to maintain uniform positioning in all rotational positions between the scanning element and the record supporting element. n

CHARLES J. YOUNG.

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