Process and device for testing cigarettes or the like for faults

For testing cigarettes, a test head confronts end faces of the cigarettes. Light beams emitted by a light transmitter are transmitted through those cigarettes having a tobacco deficiency. The transmitted light exits from sides of the defective cigarettes and is received by a transversely arranged receiver responsive to light transmitted through the cigarette paper.

DESCRIPTION 
The invention relates to a process for testing cigarettes or the like for 
faults as regards the presence of (sufficient) tobacco, cigarette filters, 
etc., by means of light which is directed onto the cigarette and is 
emitted by a light source and which is received by a photosensitive 
receiver. 
It is necessary to test cigarettes for any faults, especially as regards a 
sufficient filling of tobacco, in conjunction with the packaging of the 
cigarettes. Conventionally, cigarette groups each assigned to a cigarette 
pack are tested before being enveloped in an inner wrapper (tin-foil 
blank). Cigarette groups or cigarette packs with at least one defective 
cigarette are separated out during the further packaging operation. 
In a known device for testing cigarettes for faults by means of light, the 
light is directed towards the free end face of the cigarette. The relative 
arrangement here is such that the light reflected from the end face of the 
cigarette, namely the tobacco, is received by a receiver. If tobacco is 
missing in this region, light reflection cannot take place. The particular 
cigarette is identified as being defective. (German Offenlegungsschrift 
3,201,666). 
The testing of cigarettes for faults by means of light reflection is 
inaccurate because the fault signal is influenced solely by the state of 
the cigarette immediately in the region of the end face. 
The object on which the invention is based is to propose measures for 
testing cigarettes or the like for faults, by means of which perfect and 
defective cigarettes can be identified quickly and reliably with the aid 
of simple test means. 
To achieve this object, the process according to the invention comprises 
passing the light through at least a part region of the cigarette 
(transmitted-light process). 
Accordingly, in the process of the invention, some of the light passes 
through the cigarette or through its envelope (cigarette paper) when a 
cigarette is defective. In the preferred embodiment of this process, light 
is guided into the cigarette via its free end face and, in the event of a 
fault, is received via a laterally arranged receiver which is consequently 
directed towards the cigarette envelope (cigarette paper). The particular 
receiver is arranged adjacent to the end face of the cigarette and 
laterally next to it. In the event of a defective cigarette, namely when 
there is no tobacco or an insufficient density of tobacco in the region of 
the end face, light consequently enters the cigarette in a longitudinal 
direction and, because it is deflected and passes through the cigarette 
paper, is received by the receiver. 
The fault testing according to the invention is appropriately carried out 
on cigarette groups each assigned to a cigarette pack. A device which is 
especially suitable for this purpose consists of a test head with a holder 
(housing) having a number of receivers corresponding to the number of 
cigarettes to be tested. Where cigarette groups having several layers of 
cigarettes are concerned, the latter are offset relative to one another, 
so that at least one end region of each cigarette is free to allow a 
receiver to be arranged appropriately. The test head or housing is made 
appropriately step-shaped on the side facing the cigarette group, so that 
the end regions facing it can fit into corresponding recesses in the test 
head. 
The cigarettes can be tested by means of visible, especially diffuse light 
which is generated by individual lamps (filament lamps) or by a common 
light source. Alternatively, infrared light appropriate for short cycle 
times and therefore for extremely short tests is suitable. 
The cigarette groups are supplied, in the formation corresponding to the 
cigarette pack, to a test station in pockets of a conveyor. In this test 
station, testing is carried out during a short standstill phase or 
advantageously during the conveying movement of the cigarette groups. 
Further features of the invention relate to details of the test process and 
of the device.

The practical examples and exemplary embodiments illustrated in the 
drawings relate to the testing of cigarettes 20 (the so-called head check) 
before they are packaged. 
FIGS. 1 and 2 illustrate diagrammatically the testing of cigarettes 20 with 
reference to a defective cigarette (FIG. 1) and with reference to a 
cigarette which is made properly (FIG. 2). These are cigarettes with a 
filter 21. Testing is carried out in the region of the end of the 
cigarettes 20 which is located opposite the filter 21. For this purpose, 
in the exemplary embodiment illustrated, light beams 22 are introduced 
into the cigarette 20 via an end face 23 in the longitudinal direction, 
that is to say in the axial direction. In the cigarette 20 according to 
FIG. 1, there is an incomplete filing of tobacco 24 in a region adjacent 
to the end face 23, in particular with a void 25 free of tobacco. The 
light beams 22 entering the cigarette 20, by being partially deflected to 
the side, generate light in the region of a cigarette envelope, namely in 
the cigarette paper 26. Deflection beams 27 pass through the cigarette 
paper 26 and because of the missing tobacco can be received here by a 
suitable receiver 28, especially a photodiode. 
As regards the cigarette 20 in FIG. 2, which is properly filled with 
tobacco, there is no transverse deflection of light. On the contrary, the 
light is reflected or absorbed in the region of the end face 23. 
The light signal received by the receiver 28 is suitably evaluated by 
machine, in such a way that the cigarette or a cigarette group or a 
cigarette pack, as the case may be, is separated out from the packaging 
cycle. 
A diaphragm 29 located in front of the end faces 23 of the cigarettes 20 
has a diaphragm aperture 30 which is centered on the end face 23 and which 
has, in the present case, a smaller diameter than this. 
The testing of cigarettes 20 is appropriately carried out on cigarette 
groups 31. These consist of a number of cigarettes 20 corresponding to the 
finished cigarette packs and appropriately arranged in several, for 
example three layers 32, 33, 34. In the often customary formation 
illustrated here, the outer layers 32 and 34 consist of seven cigarettes 
and the middle layer 33 of six cigarettes. The latter are arranged in a 
"saddle position" in relation to the cigarettes of the outer layers 32 and 
34. 
A test head 35 consisting of a closed housing 36 serves for the 
(simultaneous) testing of the cigarettes 20 of a cigarette group 31 formed 
in this way. The necessary means for testing the cigarettes 20 are 
accommodated in a front wall 37 which faces the cigarettes 20 to be 
tested, of the housing 36. Electrical or electronic devices are located 
inside the housing 36. 
In the exemplary embodiment of FIGS. 3 to 5, each cigarette 20 to be tested 
has assigned to it a separate receiver 28 which, as described, is directed 
transversely to its axis. Furthermore, each cigarette 20 has assigned to 
it a separate light source in the form of a small electric lamp 38. The 
lamps 38 designed, for example, as conventional signal lamps are suitably 
mounted in retaining bores 39 in the front wall 37 of the housing. 
Likewise, the (cylindrical) receivers 28 are mounted in transversely 
directed retaining bores 40 in the front wall 37. 
For testing the cigarettes 20 of a cigarette group 31 consisting of more 
than two layers, the layers are offset relative to one another. In the 
present exemplary embodiment, the middle layer 33 is offset relative to 
the outer layers 32 and 34 in the manner of steps in the direction of the 
test head 35. As a result, the end regions of the cigarettes 20 of the 
middle layer 33 are likewise exposed, so that the associated receivers 28 
can be arranged adjacent to the ends of these cigarettes. 
The front wall 37 of the housing 36 is made step-shaped to match the offset 
arrangement of the end regions of the cigarettes 20. The wall steps 41, 
42, 43 and 44 obtained as a result serve for accommodating transmitters 
(lamp 38) and/or receivers 28, the wall steps 41 to 44 being 
correspondingly thicker, in each case in the region where one component or 
the other is accommodated, than the remaining part of the housing 36. 
In particular, an upper wall step 41 serves for accommodating the 
(vertically directed) receivers 28 of a row of receivers for the upper 
layer 34. The next wall step 42 set back inwards serves both for 
accommodating a further row of receivers 46 and for accommodating a row of 
lamps 47. The receivers 28 and the lamps 38 are mounted, in the region of 
this wall step 42, in retaining bores 39 and 40 located next to one 
another and having longitudinal axes offset 90.degree. relative to one 
another. 
Formed on the inside of the front wall 37, in the region of the middle 
layer 33, is a rib-like extension 48 which serves for mounting a row of 
lamps 49 in corresponding retaining bores 39. The following wall steps 43 
and 44 serve for accommodating a further row of lamps 50 and a row of 
receivers 51 respectively. Accordingly, the receivers 28 of the lower row 
of receivers 51 act in an opposite direction (downwards) to the receivers 
of the upper row of receivers 40. 
In this embodiment, the lamps 38 are supplied with current in a parallel 
connection via current leads 52. 
The offsets in the front wall 37 of the housing 36 which are formed by the 
wall steps 41 to 44 are open on the sides, so that a continuous stepped 
recess is formed over the entire length or width of the housing 36 and 
also continues in the region of side walls 53, 54 of the housing. 
The embodiment according to FIG. 6 differs from that described above in 
that, here, a common light source in the form of a central lamp 55 is 
arranged within the housing 36. The (diffuse) light generated by this is 
guided to the end faces 23 of the cigarettes 20 via diaphragm apertures 30 
in the front wall 37. Even here, the front wall 37 of the housing 36 is 
made step-like in a similar way to the exemplary embodiment of FIGS. 3 to 
5, with wall steps 41 to 44 of corresponding design and corresponding 
function. However, there are no receptacles for the separate lamps 38. 
A special exemplary embodiment as regards the light source and light 
guidance is illustrated in FIG. 7 in a horizontal section through the 
housing 36 in the region of the smallest cross-section. Light emerging 
from a central lamp 56 is supplied via separate light guides 57, 
especially glass-fiber cables, to each individual cigarette 20 or to each 
end face 23 of the latter. The light guides 57 are each deflected 
arcuately according to requirements. The angle of deflection is not 
greater than 90.degree.. The light guides 57 starting in the region of the 
central lamp 56 end in light-guide bores 58 in the front wall 37, 
specifically in the region of the wall steps 41 to 44. The diameter of the 
light-guide bores 58 corresponds to the outside diameter of the light 
guides 57. These terminate flush with the outer surface of the respective 
wall step 41 to 44. This embodiment corresponds to those already described 
as regards the arrangement of the receivers 28 in individual rows of 
receivers 45, 46 and 51. 
Instead of light sources emitting visible light, other designs are also 
advantageous, especially using infrared light, the latter being especially 
advantageous for short work cycles. 
The cigarettes 20 or cigarette groups 31 are appropriately supplied in 
succession to a test station 59 by means of a conveyor. The test device, 
namely the test head 35, is attached fixedly in this test station, in such 
a way that to conduct the test the test head 35 can be advanced by means 
of a short stroke to the particular cigarette group 31 to be tested (FIG. 
8). Moreover, in the region of this test station 59, the relative position 
of the cigarettes 20 within the cigarette group 31 is temporarily changed 
by shifting the layers 32, 33 and 34 out of alignment. In the exemplary 
embodiment of FIG. 8, there is for this purpose a ram 61 which is 
step-shaped, in particular designed with a projection 60, and which is 
brought up against the cigarettes 20 on the side of these located opposite 
the test head 35 (against the filter 21) and thereby displaces the 
initially aligned cigarettes 20 relative to one another in the way 
described. In a station following the test station 59, the original 
aligned relative position of the cigarettes 20 can be restored, preferably 
by means of a counter-slide (not shown) which is effective on the same 
side as the test head 35. 
The cigarette group 31 is received in individual pockets 62 of a preferably 
endless conveyor. In the exemplary embodiment of FIG. 8, these pockets 62 
are arranged on the outer periphery of a revolving turret 63. 
An alternative to this is illustrated in FIG. 9. Here, the pockets 62 are 
links of a pocket chain 64 acting as a conveyor. The pocket chain is 
designed in a known way so that the cigarette group 31, because of its 
special formation, is received positively in the pocket 62. 
Here, the test head 35 is arranged laterally next to the path of movement 
of the pocket chain 64 and can be advanced by means of a lateral stroke to 
the particular cigarette group 31 to be tested. The test head 35 is 
designed, here, according to one or other of the exemplary embodiments 
described. The cigarettes 20 can be tested during a momentary brief 
standstill of the pocket chain, but alternatively also during continued 
(uniform) movement. In the latter case, the fixed test head 35 is 
sensitized briefly in such a way that the light signal, preferably 
infrared light, is emitted when the cigarettes 20 of the cigarette group 
31 are momentarily co-ordinated with the test means (lamp, etc.) of the 
test head. 
In the embodiment according to FIG. 10, a special test head 65 which simply 
has a number of cigarette-testing means corresponding to the number of 
layers 32, 33, 34 is used. These can be, in particular, the test means 
described in relation to FIGS. 3 to 7. The test head 65 can likewise be 
designed with a step-like front wall. Three transmitters 66, 67, 68 (and 
corresponding receivers) are arranged at the height of the layers 32, 33, 
34, specifically offset relative to one another in the conveying 
direction, so that the transmitters 66, 67, 68 are each located opposite a 
cigarette of the three layers 32, 33, 34 simultaneously. Consequently, 
here, the cigarettes of the individual layers are tested in succession. 
This test process is appropriately carried out during the continuous 
movement of the pocket chain 64, the transmitters 66 to 68 being activated 
briefly and in synchnonism with the movement of the cigarette group 31, so 
that all the cigarettes are sensed optically in succession.