Method and apparatus for making X-ray images

Sheet-like dielectric receptors which are to be exposed to object-modulated X-rays in the interelectrode gap of an ionography imaging chamber are attached to sheet-like carriers so that the carriers extend laterally beyond the reactors. The carriers are thereupon transported through the interelectrode gap and through successive stations of a xerographic printer which renders the latent imges of objects visible and subjects the receptors to other treatment. The carriers can be attached to receptors by resorting to an adhesive, by the application of electrostatic charges and/or by causing the marginal portions of the carriers to engage the receptors by suction. The carriers are provided with semiconductive layers whose surface resistance can be varied at or prior to entry of carriers and attached receptors into the various stations; this can be achieved by utilizing semiconductive layers whose resistance can be influenced by changing the pressure of the surrounding atmosphere or by utilizing photosensitive layers whose resistance changes in response to exposure to light. The layers are regenerated upon separation of finished receptors so as to allow for renewed use of the respective carriers.

BACKGROUND OF THE INVENTION 
The present invention relates to a method and apparatus for making X-ray 
images. More particularly, the invention relates to improvements in a 
method and apparatus for making X-ray images without the use of 
conventional X-ray film. Still more particularly, the invention relates to 
a method and apparatus for making X-ray images on sheet-like dielectric 
receptors which are exposed to X-rays in the interelectrode gap of an 
ionography imaging chamber and are thereupon developed by resorting to 
xerographic techniques. The invention also relates to novel and improved 
means for supporting and advancing sheet-like receptors in the course of 
exposure to X-rays and during further processing. 
It is known to produce latent images of objects on a sheetlike dielectric 
receptor while the receptor is located in the interelectrode gap of an 
ionography imaging chamber. The gap is filled with a compressed gaseous 
medium, preferably a noble gas, which is an efficient absorber of 
object-modulated X-rays and creates secondary electrons with the result 
that the receptor is provided with an electrostatic latent image which is 
thereupon made visible in a developing apparatus by using 
electrostatically attractible toner material. In the last stage, the toner 
image is fixed on the receptor in a manner known from the art of 
xerographic copying or printing. 
A drawback of presently known methods and apparatus of the just outlined 
character is that the making of a fixed toner image takes up too much 
time. Dielectric receptors are introduced into and removed from the 
imaging chamber by hand. Also the transfer of receptors, which carry 
latent images, to and from further processing (developing and fixing) 
stations is effected by hand. Automatic transport of such receptors was 
considered impractical or impossible because an X-ray image is normally 
without margins (i.e., the image covers the entire exposed side of the 
receptor) so that the transporting means would have to engage those areas 
of a receptor which are contacted by toner material. The provision of an 
unexposed margin on receptors (which margin could be engaged and moved by 
an automatic transporting mechanism) is undesirable because the margin 
would have to be removed upon completion of treatment and the removed 
material would represent a highly expensive waste which would have to be 
processed (disposed of) in a costly and time-consuming manner. Moreover, 
the provision of margins would complicate the making of X-ray images on 
sheets with rounded corners which are preferred by technicians and 
physicians due to convenience of manipulation and storage. 
SUMMARY OF THE INVENTION 
An object of the invention is to provide a novel and improved method of 
making X-ray images on sheet-like dielectric receptors which are exposed 
to X-rays in an ionography imaging chamber and are thereupon developed by 
xerographic techniques. 
Another object of the invention is to provide a method which renders it 
possible to expose and develop successive receptors of identical size 
and/or different size and/or shape in a fully automatic or semiautomatic 
way and at a speed which greatly exceeds the speed of making X-ray images 
in accordance with conventional methods. 
A further object of the invention is to provide a novel and improved 
apparatus which can be utilized for the practice of the above outlined 
method and which is sufficiently versatile to allow for exposure and other 
treatment of larger, smaller, similar and/or differently configurated 
receptors. 
An additional object of the invention is to provide novel and improved 
means for supporting and transporting receptors through the exposure, 
development and other stations of the apparatus. 
Still another object of the invention is to provide an apparatus which 
requires a minimum of attention and which can be used for the making of 
X-ray images without margins and with rounded edges on the respective 
receptors. 
Another object of the invention is to provide a novel carrier for transport 
of receptors through the improved apparatus. 
A further object of the invention is to provide a carrier which can be 
reused as often as desired, which can properly support and move receptors 
of any practical size and/or shape, and whose presence does not affect the 
exposure and/or other treatment of receptors during the making of X-ray 
images. 
An ancillary object of the invention is to provide a novel and improved 
method of attaching the carrier to a receptor and a novel and improved 
method and device for separating receptors from the respective carriers. 
A further object of the invention is to provide the apparatus with novel 
and improved means for attaching receptors to carriers prior to 
introduction of receptors into the imaging chamber. 
One feature of the invention resides in improvements in a method of making 
X-ray images on sheet-like dielectric receptors which are exposed to 
X-rays in the interelectrode gap of an ionography imaging chamber to 
produce thereon latent images of selected objects, such latent images 
being thereupon made visible by xerographic techniques (by resorting to a 
suitable toner material) at a developing station. The improvements include 
the steps of attaching each receptor (the receptors may be of identical 
size or of different sizes) to a discrete sheet-like carrier which is at 
least partially conductive and extends beyond the respective receptor, and 
transporting the thus attached receptors seriatim in a predetermined 
direction toward, through and past the imaging chamber and developing 
station by way of the respective carriers. If the developing step includes 
contacting the image-bearing surfaces of receptors with toner material 
(which can be distributed in a liquid carrier medium), the method normally 
comprises treating each receptor (with a visible image thereon) at a 
fixing station. The improvements then preferably further comprise the step 
of transporting the receptors from the developing station toward and 
through (and preferably beyond) the fixing station through the medium 
(i.e., by way) of the respective carriers. 
Each carrier preferably extends at least beyond two opposite sides of the 
respective receptor and transversely of the direction of transport, and 
each transporting step preferably comprises advancing the receptors by 
transmitting motion (e.g., by means of rollers, rolls and/or belts) to 
those portions of the carriers which extend beyond the respective 
receptors. 
The attaching step may comprise temporarily securing the receptors to the 
respective carriers by the application of suction to such parts (e.g., to 
hollow marginal beads) of the carriers which are adjacent to the marginal 
portions of the respective receptors to thereby hold the aforementioned 
parts in engagement with the associated receptors. Alternatively, the 
attaching step may comprise applying electrostatic charges to the carriers 
and the respective receptors. Still further, the attaching step may 
comprise bonding the receptors to the respective carriers by films of a 
highly viscous liquid. The carriers can be secured to the receptors by 
resorting to two or more different attaching steps, e.g., by electrostatic 
charging and by the application of adhesive films. 
The other side of each carrier may be provided with a layer of 
semiconductive material. Such layers are subjected to elevated gas 
pressure (preferably to the pressure of a noble gas) during exposure of 
the respective receptors to X-rays in the interelectrode gap of the 
imaging chamber, and to substantially atmospheric pressure during 
transport through the developing station; this changes the surface 
resistance of the layer at the respective stations. 
The layers of the carriers may consist of photoconductive material, and the 
improvements then preferably further comprise the steps of shielding such 
layers from light prior to transport of the carriers into and during dwell 
of the carriers in the interelectrode gap, and thereupon exposing the 
layers to light (e.g., daylight and/or ultraviolet light) not later than 
at the developing station (i.e., during transport between the gap and the 
developing station or at the developing station proper). 
The carriers are separated from the respective receptors subsequent to 
transport through the developing station (preferably subsequent to 
transport through the aforementioned fixing station), and the 
semiconductive layers of the thus separated carriers are preferably 
subjected to a regenerating treatment (e.g., heating) so that the carriers 
can be attached to fresh receptors for renewed transport toward, through 
and beyond the interelectrode gap, developing station and fixing station.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows an apparatus wherein a tray or an analogous receptacle 1 
stores a supply or stack of sheet-like flexible carriers 2. Additional 
trays or receptacles 3, 4, 5 are provided for storage of stacks of 
sheet-like dielectric receptors 6a, 6b, 6c of different sizes. The 
apparatus further comprises means (e.g., driven feed rolls 7, 7a, 7b, 7c) 
for respectively drawing discrete carriers 2 and receptors 6a, 6b, 6c from 
the corresponding trays 1, 3, 4 and 5. When a receptor 6a, 6b or 6c is to 
be exposed to object-modulated X-rays, a carrier 2 is advanced onto a 
platform 8 prior to or simultaneously with advancement of a receptor 6a, 
6b or 6c so that the selected receptor overlies the carrier. On its way 
from the tray 1 toward and onto the platform 8, each carrier 2 advances 
below a paster having a roller-shaped applicator 9 and a nozzle or wick 10 
which delivers a layer or film of a highly viscous liquid to the periphery 
of the applicator 9. The latter transfers the film onto a predetermined 
portion of the upper side of the moving carrier 2. The nature of liquid is 
such that it causes the selected receptor 6a, 6b or 6c to adhere to the 
carrier 2 as well as to establish a satisfactory electrical connection 
between the overlapping sheet-like components on the platform 8. 
The platform 8 is followed (as considered in the direction of transport of 
the carrier 2 and a selected receptor 6a, 6b or 6c) by a corona discharge 
device through which the laminated structure or sandwich including a 
carrier and a receptor is advanced by means of two pairs of transporting 
rolls 24 located immediately downstream of the platform. As shown in FIG. 
3, the corona discharge device comprises a grounded housing 11 which 
confines a wire-like discharge electrode 12. The electrode 12 is located 
opposite a grounded electrode 13 and is connected to a high-voltage power 
supply 14. 
FIG. 3 further shows that the carrier 2 (whose main or first layer 
preferably consists of polypropylene with a specific resistance of 
10.sup.12 -10.sup.13 ohms per unit area) comprises a second or backing 
layer 2a of semiconductive material, preferably amorphous selenium. It is 
equally possible to resort to a different backing layer which is a 
semiconductor (photoconductor) and has a dark resistance of at least but 
preferably more than 10.sup.9 ohms per unit area. The reference character 
2b denotes the film of highly viscous liquid which is applied by the 
paster 9, 10 of FIG. 1. This liquid may be glycerine or silicone oil whose 
electric resistance is lower than that of a receptor 6a, 6b or 6c, e.g., 
by admixing thereto a comminuted conductive substance such as graphite 
powder. During travel of a sandwich through the corona discharge device, 
the electrodes 12, 13 apply to the carrier 2 and the receptor (e.g., 6a) 
potentials in a manner as shown in FIG. 3. The electrostatic forces which 
develop as a result of such charging of the components 2, 6 a cause the 
latter to adhere to the former. Such adherence is in addition to that 
which is caused by the adhesive film 2b. 
The thus treated sandwich consisting of receptor 6a and carrier 2 (to which 
the receptor adheres) is advanced into the ionography imaging chamber a 
portion of which is shown on a larger scale in FIG. 5. This chamber 
comprises a first or upper section 15 and a second or lower section 16. 
The sections 15, 16 are connected to each other with interposition of a 
sealing element 17 (see FIG. 1). Reference may be had to our copending 
application Ser. No. 666,410 filed Mar. 12, 1976; the matter of the 
copending application is incorporated herein by reference. The sections 
15, 16 define an interelectrode compartment or gap 20 which is surrounded 
by the sealing element 17 and contains a supply of compressed noble gas or 
Freon. The manner in which the gas can be introduced into the gap 20 is 
disclosed in our copending application Ser. No. 666,410 and also in U.S. 
Pat. No. 3,774,029 granted Sept. 20, 1973 to Muntz et al. The gas in the 
gap 20 absorbs the X-rays which issue from a source 18 and penetrate 
through or pass around an object 19 (both shown in FIG. 1) with attendant 
ionization of the gas. The pressure of gas in the compartment 20 is 
reduced prior to introduction of a sandwich 2, 6a or 2, 6b or 2, 6c. FIG. 
5 shows a channel 26 which is provided in the section 16 and is connected 
to a gas evacuating pump, not shown. The pump feeds the evacuated gas into 
a suitable storage vessel. 
A sandwich 2, 6a or 2, 6b or 2, 6c can be introduced into and removed from 
the gap 20 upon deflation of the sealing element 17. Such inflatable 
sealing element is disclosed in our copending application Ser. No. 
666,410. When inflated, the sealing element 20 engages the carrier 2 in 
regions surrounding the attached receptor 6a, 6b or 6c. 
The gap 20 is flanked by electrodes 21 and 23 which are connected to an 
external 15,000 volt energy source 75. The electrodes in the space between 
the sections 15, 16 of the imaging chamber are so-called virtual 
electrodes of the type disclosed, for example, in U.S. Pat. No. 3,859,529 
granted Jan. 27, 1975 to Proudian et al. The electrodes 21, 23 are 
respectively surrounded by semiconductors 22, 24 having a dark resistance 
10.sup.9 ohms per unit area. An electrostatic latent image develops at the 
exposed side of the receptor 6a as a result of deposition of ions which 
develop in the gap 20 due to the influence of the accelerating potential 
difference applied between the electrodes 21 and 23. 
When the ionization imaging chamber comprises virtual electrodes, the 
surface resistance of the semiconductor layer 2a must exceed the surface 
resistance of the adjacent electrode (23 in FIG. 1 or 5) by a factor of 
10-100 in order to insure that a transverse current of predetermined 
strength can flow along the electrode. The resistance of the material 
which is normally used for the making of virtual electrodes is 
approximately 10.sup.8 ohms per unit area. Therefore, the resistance of 
the layer 2a should be in the range of 10.sup.9 -10.sup.10 ohms per unit 
area. On the other hand, the deposition of toner particles on the exposed 
receptor (i.e., the equalization of charges which is a necessary adjunct 
of such deposition) is promoted if the resistance of the layer 2a during 
travel of the respective sandwich through the developing unit does not 
exceed 10.sup.6 ohms per unit area. 
In order to prevent sparking during separation of an exposed receptor from 
the electrode 23, the receptor must be separated from the electrode 
together with the respective layer (whose charge is mirror symmetrical to 
the charge representing the latent image on the receptor). Thus, and in 
the absence of a layer whose charge can be changed from station to 
station, it would be necessary to apply to the carrier 2 a first layer 2a 
(with a first conductivity) at the exposure station and a layer of 
different second conductivity at the developing station. The 
semiconductive layer 2a of the improved carrier renders this unnecessary 
because it can be influenced by external means prior to entering the 
exposure station and the developing station so that it exhibits optimum 
electrical characteristics for the treatment of associated receptor at the 
respective station. 
It would be conceivable to apply a semiconductive layer directly to the 
rear sides of the receptors 6a, 6b and 6c. However, the provision of 
semiconductor layer 2a at the rear sides of carriers 2 exhibits the 
advantage that its material can be selected by disregarding its 
appearance. Thus, if the semiconductor layers 2a were applied to the 
receptors, they would have to be made of light-transmitting material which 
would greatly reduce the number of available materials. In accordance with 
the present invention (according to which the layers 2a are applied to the 
carriers rather than to the receptors), the only important consideration 
in connection with selection of the material of receptors is to insure 
that such material exhibits optimum characteristics for exposure to X-rays 
and for subsequent development of latent images by xerographic techniques. 
For example, each receptor 6a, 6b or 6c may constitute a transparent sheet 
consisting of polyester. 
The exposed receptor 6a (which continues to adhere to the carrier 2) is 
removed from the imaging chamber by the first of several sets of 
transporting rolls 25 to enter a developing unit. The first or foremost 
rolls 25 engage the lateral marginal portions at the leading end of the 
carrier in the gap 20 and move the sandwich into the range of the 
next-following rolls 25. The leader of the sandwich 2, 6a is then engaged 
and advanced by the adjacent reach or stretch of a belt conveyor 29 which 
is trained over pulleys 27, 28 and engages the backing layer 2a of the 
carrier. The conveyor 29 moves the receptor 6a past an apertured 
developing electrode 30 (FIG. 6) which is mounted at the top of a trough 
or vessel 31. The latter contains a battery of nozzles 61 which discharge 
streams of developing material in directions indicated by arrows. Such 
material passes through the apertures of the electrode 30 and continuously 
contacts the latent image at the exposed side of the receptor 6a. The 
arrangement of nozzles 61 insures that the receptor 6a is constantly 
contacted by fresh developer material. The nozzles 61 receive developer by 
way of a conduit 32 which is connected to a suitable source by way of a 
pump, not shown, serving to convey fresh developer in the direction 
indicated by arrow A. A suction pipe 33 serves to evacuate spent developer 
from the trough 31 in the direction indicated by arrow B. Thus, the trough 
31 contains a body of developer which continuously receives fresh material 
via conduit 32 and continuously supplies material to the source via pipe 
33. 
The trough 31 is surrounded by a further vessel 34 which intercepts and 
collects liquid developer overflowing the edges of the trough 31. The 
outlet of the collecting vessel 34 is connected with the source by a pipe 
35 which conveys the liquid in the direction indicated by arrow C. 
The electrical properties of the layers 2a are influenced by subjecting 
such layers to different pressures. Thus, the layers 2a are subjected to 
superatmospheric pressure of a high Z gas during dwell of the respective 
carriers in the interelectrode gap 20, and the pressure is reduced to 
atmospheric pressure during treatment of receptors at the developing 
station between the conveyor 29 and electrode 30. The elevated pressure in 
the gap 20 brings about a temporary rise in surface resistance of the 
layers 2a, and such resistance reassumes its normal (lower) value during 
treatment of receptors in the developing unit where the pressure of air at 
the exposed sides of layers 2a equals or approximates atmospheric 
pressure. 
If the layers 2a consist of photosensitive material, the carriers 2 are 
shielded from light prior to entry into and during dwell in the 
interelectrode gap 20, and are exposed to daylight and/or ultraviolet 
light on their way toward and/or at the developing station (see the lamp 
37 of FIG. 1 which illuminates the layers 2a). Regeneration of such 
photosensitive material can be effected at the station including the 
heating coils 52, i.e., by the application of heat. This reduces the 
surface resistance of the layers by a factor of 10 to 100. The number of 
carriers which must be stacked in the tray 1 of FIG. 1 (and whose layers 
2a consist of photoconductive material) depends on the maximum number of 
exposures to be made during the interval which is required for 
regeneration of a layer in the tray 50. As soon as a layer is regenerated, 
the respective carrier can be transferred or transported from the tray 50 
and back into the tray 1. Such mode of manipulating the carriers insures 
that the apparatus can operate properly and with a high output by 
utilizing a relatively small number of carriers. 
Regardless of whether the layers 2a consist of a photoconductive or other 
material, the electrical resistance of the first or main layers of the 
carriers 2 preferably equals or approximates the maximum resistance of the 
respective layers 2a. 
FIG. 6 shows in greater detail the conditions prevailing in the developing 
unit during development of a latent image. The liquid developer which is 
supplied by the orifices of the nozzles 61 contains positively charged 
toner particles 36 which migrate toward the negatively charged portions of 
the image-bearing exposed surface of the receptor 6a. The conveyor 29 
consists of electrically conductive material and is connected to the 
ground. The resulting equalization of charges renders it necessary to 
remove a portion of the mirror symmetrical charges which are applied to 
other conductive layers of the sandwich. In order to insure rapid removal 
of such charges, each photosensitive layer 2a travels along a light source 
37 (FIG. 1) on its way toward the developing station; this enhances the 
conductivity of the backing layer. The light source 37 is mounted in front 
of a reflector 53. 
The sandwich which issues from the developing unit including the electrode 
30 is advanced past an infrared lamp 38 which is mounted in a housing 54 
and is located opposite a reflector 39 in order to reduce radiation 
losses. The parts 38, 39 form a fixing unit for the developed image on the 
receptor 6a; this unit causes evaporation of solvent in the developing 
liquid which is supplied by the nozzles 61 with attendant softening of the 
resinous ingredient of the carriers of coloring matter, i.e., the receptor 
6a is provided with a fixed toner image. 
The sandwich 2, 6a then enters a separating or peeling unit, shown in FIG. 
2, wherein the receptor 6a is separated from its carrier 2. The direction 
of movement is indicated by arrow D. The leader of the sandwich enters the 
nips between two endless bands 41, 42 (which are trained over a front 
roller 40 and rear rollers 45, 46) and biasing rolls 43, 44 located 
opposite the roller 40. The bands 41, 42 are tensioned by rolls 47, 48 so 
that the upper reach of each of these bands includes two mutually inclined 
portions 41A, 41B and 42A, 42B. The width of the carrier 2 exceeds the 
width of the receptor 6a, i.e., the marginal portions of the carrier 
travel with the upper reaches of the bands 41, 42 and the receptor 6a is 
located in the space between such bands. Consequently, the receptor 6a is 
separated from the carrier 2 in the region where the carrier is flexed by 
the biasing rolls 47, 48 and becomes separated from the receptor 6a which 
descends into a collecting tray 49. The carrier 2 advances into a separate 
tray 50. The latter is located adjacent to (e.g., below) a set of heating 
coils 52 disposed in front of a reflector 51 and serving to effect rapid 
regeneration of the backing layer 2a. The layer 2a is relieved of the 
remnant of its charge and rapidly reassumes its dark conductivity. The 
carrier 2 is then ready for transfer (or transport) back into the tray 1. 
The tensioning rolls 47, 48 are preferably positioned in such a way that 
they cause successive increments of a carrier 2 to assume an arcuate shape 
with a relatively small radius of curvature. This enhances the separation 
of the receptor. The thus separated receptor descends by gravity in the 
space between the bands 41 and 42. 
FIG. 2 shows that the carrier 2 has two marginal portions 2D, 2E which 
extend beyond two opposite sides of the receptor 6a and transversely of 
the direction of transport (arrow D) of the carrier along the path 
extending from the tray 1, through the imaging chamber, the developing 
station and the fixing station. The marginal portions 2D, 2E are elongated 
strips which are parallel to the direction of movement of the carrier 2. 
The rolls 24, 25 and 43, 44 engage the marginal portions 2D, 2E of the 
carrier 2, i.e., such rolls move the receptor 6a exclusively through the 
medium of the carrier. This renders it possible to make X-ray images which 
are without margins and exhibit rounded corners for convenience of 
handling and storage. 
FIG. 2 further shows that the marginal portion 2F at the leading end of the 
carrier 2 extends beyond the leader of the receptor 6a. This is desirable 
for convenient separation of the two sheets while the carrier 2 is 
advanced by the bands 41, 42. 
The carrier 2 may but need not be rectangular or square; all that counts is 
to insure that the carrier extends beyond the largest receptor and that it 
be at least slightly conductive. The configuration of the receptors 6a, 
6b, 6c can also deviate from a rectangular or square shape, as long as the 
receptors are smaller than the carrier Z so that the latter extends beyond 
the attached receptor and its non-overlapped portions can receive motion 
from rolls, wheels, bands and/or other suitable transporting elements. 
Conductivity of the carriers 2 is desirable and advantageous because it 
allows for continuous adherence of carriers to the respective receptors 
during each stage of treatment which is needed to form latent images, to 
render the images visible and to fix the developed images on the 
receptors. The thickness of the first or main layer of a carrier may be 
between 180 and 400.mu.. 
FIG. 4 shows a carrier 2' which is formed with a circumferentially complete 
hollow marginal bead 2c. The marginal bead 2c can be depressed and 
deformed by a suitable mandrel 55 in such a way and to such an extent that 
its interior communicates with a channel 56 which is provided in the 
mandrel and is connected to a suction generating device, not shown. The 
resulting vacuum in the interior of the bead 2c causes the latter to bear 
against the adjacent marginal portions of the receptor 6 (this receptor 
may be any one of the receptors 6a, 6b, 6c shown in FIG. 1) with the 
result that the receptor is attached to the carrier 2'. At the separating 
station, the bead 2c is engaged by another mandrel which admits air into 
the interior of the bead so that the latter becomes separated from the 
exposed and developed receptor and the receptor becomes separated from the 
carrier 2'. The mandrel 55 can be movably mounted in the region of the 
platform 8 of FIG. 1. 
FIGS. 4 and 4a further show that the free edge portion of the bead 2c has a 
circumferentially complete cutout bounded by surfaces 2d and 2e. This 
cutout is outwardly adjacent to an opening 2g which communicates with the 
internal space 2f of the bead 2c. The reference character 2h denotes the 
exposed underside of the film 2b. The bead 2c is elastic but is 
sufficiently stiff to insure that the surface 2e abuts agaist the adjacent 
portion of the underside 2g prior as well as subsequent to evacuation of 
some air from the opening 2g and space 2f. Minor uneveness of the 
underside 2h and/or surface 2e are compensated for by elasticity of the 
bead portion below the surface 2e. 
If the mandrel 55 evacuates some air from the space 2f, the resulting drop 
of pressure in the interior of the bead 2c need not be sufficiently 
pronounced to effect any deformation of the bead. However, the drop of 
pressure is felt in the gap (if any) between the upper side of the central 
portion of the carrier 2' and the underside 2h of the receptor 6 whereby 
the receptor is attracted to the carrier. The just mentioned gap 
communicates with the space 2f by way of the opening 2g. It has been found 
that the evacuation of relatively small quantities of air from the space 
2f suffices to insure that the carrier attracts the receptor with a 
considerable force. 
When the mandrel 55 is moved to the position shown in the left-hand portion 
of FIG. 4a (such position corresponds to the phantom-line position of the 
mandrel 55 in FIG. 4), a relatively small portion of the bead 2c is 
deformed whereby the channel 56 communicates with a portion of the space 
2f. As shown in FIG. 4b, the deformation of the bead 2c is such that the 
exchange of air between the channel 56 and space 2f takes place only in 
the region of that part of the free edge portion of the bead which is 
actually deformed by the mandrel 55. This renders it possible to control 
the extent to which air is evacuated from the space 2f and hence the force 
with which the receptor is attracted to the carrier. If the channel 56 
communicates with the atmosphere or with a source of compressed gaseous 
fluid, the establishment of communication between the channel 56 and the 
space 2f results in a weakening of the force which attracts the receptor 
to the carrier. If the channel 56 communicates with a suction generating 
device (such mandrel is located in the region of the platform 8), the 
pressure in the opening 2g and space 2f decreases whereby the carrier 
attracts the receptor with a greater force. 
This film 2b can be omitted if the receptor 6 is secured to the carrier in 
a manner as shown in FIGS. 4, 4a and 4b. 
It is further within the purview of the invention to resort to other 
techniques and means for attaching receptors 6a, 6b or 6c to their 
carriers. For example, one side of each carrier can be provided with a 
film of adhesive (such as by resorting to the paster 9, 10 of FIG. 1) 
which can be used once or more than once and is renewed when necessary, 
i.e., whenever the carrier is removed from the tray 1 or after each 
second, third, etc. transport of the carrier through the apparatus of FIG. 
1. However, it is preferred at this time to attach the receptors to their 
carriers in a manner as described in connection with FIG. 4 and/or by 
applying electrostatic charges and films of adhesive in a manner shown in 
FIGS. 1 and 3. The highly viscous adhesive (e.g., glycerine, silicone oil 
or the like) which is dispensed by the nozzle 10 of FIG. 1 exhibits the 
advantage that it establishes an intimate electrical contact between the 
carrier and the respective receptor. 
The apparatus of FIG. 1 can be readily combined with a suitable control 
system which can automatically start the feed roll 7a, 7b or 7c, depending 
upon the size of the object 19, and which can start the feed roll 7 at an 
appropriate time to insure proper attachment of the thus withdrawn carrier 
to a receptor 6a, 6b or 6c. Such control system preferably allows for 
withdrawal of two or more identically dimensioned receptors (one after the 
other) or for withdrawal of differently dimensioned receptors in any 
desired sequence. 
Without further analysis, the foregoing will so fully reveal the gist of 
the present invention that others can, by applying current knowledge, 
readily adapt it for various applications without omitting features that, 
from the standpoint of prior art, fairly constitute essential 
characteristics of the generic and specific aspects of our contribution to 
the art and, therefore, such adaptations should and are intended to be 
comprehended within the meaning and range of equivalence of the appended 
claims.