Apparatus and a method for irradiating a section of a length of a sheet-like material

An apparatus for irradiating a section forming an end portion of a length of a sheet-like material comprising a layer containing a photosensitive substance, where the boundary between said section and the rest of the length of material is defined by a divisional line, said apparatus comprising a supporting device defining a concavely curved, substantially circular cylindrical surface part; means for feeding the section in a first direction and into a first position in which the section is in abutting engagement with the cylindrical surface part and extends peripherally along the cylindrical surface part; irradiating means capable of irradiating at least a major part of said layer of said section containing said photosensitive substance and being adjacent to said divisional line; means for moving the length in a second direction substantially opposite to the first direction to a separating position, and separating means positioned at the separating position for separating the irradiated section from the rest of the length along said divisional line. The present apparatus is able to output an irradiated section having the desired dimensions directly after irradiation. No waste occurs between two irradiated images so that no cutting or the like is required in order to obtain the desired dimensions.

The present invention relates to an apparatus and a method for irradiating 
a section of a length of a sheet-like material comprising a layer 
containing a photosensitive substance. 
Apparatuses for irradiating sheet-like materials for use in e.g. printing 
machines generally incorporate one of a few distinct elements: an internal 
drum, an external drum or a so-called flat bed by which the sheet-like 
material is held during irradiation thereof. 
The present apparatus and method concern irradiating apparatuses and 
methods using the so-called internal drum principle. 
In the art, apparatuses of this type have been used for producing 
irradiated sheets of material for use in e.g. printing machines. However, 
before introducing the sheets produced by the prior art apparatuses, these 
sheets usually require manual handling in order to remove excess 
sheet-like material which is required by the apparatus during irradiation 
but which is not desired during e.g. printing in a printing machine. 
One such prior art apparatus may be seen from WO 92/14609 where, firstly, a 
section is cut from the length of material, whereafter this section is 
introduced into the internal drum for irradiation. In order to be able to 
remove the irradiated section from the internal drum, the section is cut 
to dimensions larger than those required by the irradiated image in order 
for the apparatus to be able to contact the section during irradiation so 
as to be able to remove the material subsequent thereto. 
Contacting the section during irradiation at the photosensitive side 
thereof inside the area of the irradiated image will cause the formation 
of shadows in the image. Thus, the contact is performed outside the image, 
whereby the use of excess material is required in this apparatus. 
In the present context, the desired dimensions means the desired dimensions 
along the original direction of the length of the sheet-like material. The 
dimension along the original direction of the width of the length is 
dictated by market standards and will be adapted to e.g. the printing 
machine. Each type of printing machine accepts a limited number of 
material widths, so that the irradiating apparatuses preferably should be 
able to handle a variety of widths. Thus, the dimensions of the irradiated 
sections are rarely corrected in this direction. 
In fact, often one of the sides along the direction of the width of the 
length is used for positioning the irradiated image in the printing 
machine, whereby cutting of this side might cause positioning errors in 
e.g. a printing machine. 
Other prior art instruments do not separate the irradiated image from the 
rest of the length of material before irradiation. Instruments of this 
type output the irradiated material at the other end of the internal drum 
compared to that at which the material is fed. In an instrument of this 
type, the irradiated section remains at least partly inside the internal 
drum, while the next section is irradiated. When the divisional line 
between two irradiated sections passes a cutting tool during feeding of 
more sheet-like material into the drum, the cutting is performed, whereby 
the cut-off section may obtain the desired dimensions. 
Thus, in theory, apparatuses of this type may provide some of the 
advantages of the present apparatus and method. However, a period of time 
will lapse from the point in time at which an image has been irradiated 
till the section is output from the apparatus. In order to avoid this 
delay, operators may perform a "form feed" whereby the apparatus is 
instructed to feed film material until the irradiated image has been 
output from the internal drum and cut by the cutting tool. A large part of 
the thus fed film material will not be used in the subsequent irradiation 
of the subsequent image, whereby a waste of film material is introduced. 
In a first aspect, the present invention relates to an apparatus for 
irradiating a section forming an end portion of a length of a sheet-like 
material comprising a layer containing a photosensitive substance, where 
the boundary between said section and the rest of the length of material 
is defined by a divisional line, said apparatus comprising 
a supporting device defining a concavely curved, substantially circular 
cylindrical surface part, 
means for feeding the section in a first direction and into a first 
position in which the section is in abutting engagement with the 
cylindrical surface part and extends peripherally along the cylindrical 
surface part, 
irradiating means capable of irradiating at least a major part of said 
layer of said section containing said photosensitive substance and being 
adjacent to said divisional line, 
means for moving the length in a second direction substantially opposite to 
the first direction to a separating position, and 
separating means positioned at the separating position for separating the 
irradiated section from the rest of the length along said divisional line. 
In the present connection, the divisional line is a fictitious line which 
together with the three sides of the end portion of the length defines the 
section in question. 
Typically, the irradiation is an illumination with infra-red or visible 
light, However, depending on the type of photo sensitive substance of the 
sheet-like material, the irradiation may also be performed using 
ultra-violet light or perhaps X-ray radiation. Naturally, the 
photosensitive substance and the irradiation means should match, so that 
the photosensitive substance of the sheet-like material is sensitive to 
the emitted radiation from the irradiating means. 
The present apparatus provides an apparatus which produces irradiated 
sections having the desired dimensions and which is able to output the 
irradiated sections directly after irradiation. 
Independently of where the separating means are positioned in relation to 
the internal drum, the irradiated section may be separated from the rest 
of the length of sheet-like material shortly after irradiation thereof in 
order to quickly provide the operator with the result of the operation. In 
addition, this fast action will not result in waste of sheet-like 
material. 
One setup--which is the presently preferred setup--of this first aspect of 
the invention is a setup where the section subsequent to irradiation is at 
least withdrawn from the support device in order to have the divisional 
line transferred to the separating means. 
In this setup, the second direction is a direction from the section toward 
the rest of the length of material, and the first direction is a direction 
from the rest of the length of material toward the section thereof. This 
means that, subsequent to separation of the section and removal thereof 
from the separating position and prior to feeding of the next section, no 
material is present in the supporting device. 
An alternative setup of this first aspect of the present invention may be 
one where the two directions are interchanged. Thus, in order to move the 
section to the separation means, the length is moved in the direction from 
the rest of the length toward the section. In this setup, material is 
present in the supporting device--but not necessarily in abutting 
engagement therewith--when the separation is taking place. 
In this alternative setup, the feeding of the next section means retracting 
the new cutting edge (now forming part of the next section) back into the 
supporting device (if the separating means are positioned outside the 
supporting device). 
Thus, using the present apparatus, an irradiated section is output directly 
after irradiation, whereby the operator will not experience any undue 
delay. Furthermore, the only waste of sheet-like material in the present 
apparatus is the last piece of material, which is always wasted in 
instruments of this type, as there will be no waste of material between 
the individual irradiated images. However, as will be described further 
below, a preferred embodiment of the present apparatus further includes 
means for ensuring that this last piece of material is not introduced into 
the apparatus in a manner so that it may cause problems due to jamming 
etc. 
In order to facilitate the fast outputting of a newly irradiated section, 
the present apparatus preferably comprises guiding means adapted to guide 
the section and to switch between a first and a second position where, in 
the first position, the guiding means are adapted to guide the section 
toward the supporting device when the feeding means feed the section of 
material and where, in the second position, the guiding means are adapted 
to guide the section away from the supporting device. 
It will be clear that these guiding means will be most advantageous in the 
above-mentioned first, preferred setup, whereas they would most probably 
have only little effect in the above-mentioned alternative setup, where 
the cut-off section may not be in the way for the feeding of the next 
section. 
Preferably, these guiding means are in their first position positioned 
between the separating means and the axially extending edge portion of the 
supporting device at which the length enters the supporting device when 
moving in the first direction. In this situation, when the divisional line 
is positioned adjacent to the separating means for separation of the 
section from the rest of the length, part of the section will be 
positioned in the guiding means being in their first position. Preferably, 
the guiding means are positioned close to the separating means in order 
for new cutting edge of the separated section to be guided by the guiding 
means. 
Subsequent to separation, the guiding means may shift to their second 
position so that the section may be guided away from the supporting device 
in order to prepare the apparatus for irradiation of the next section. 
Preferably, the divisional line is substantially straight so that a typical 
rotary cutter or the like may be used for the separation. 
As described above, the largest problem in prior art apparatuses of this 
type is the fact that, usually, excess material is present at at least one 
of the cutting edges of the irradiated section. Thus, in order to prevent 
this, the present irradiating means are furthermore preferably capable of 
irradiating substantially all of the layer of the section containing the 
photosensitive substance at an end portion of said section being opposite 
to said divisional line. Thus, both cutting edges of the section may 
preferably be irradiated so that no excess material may be present at 
these positions. In fact, especially when the apparatus manufactures 
positive images, it may be preferred to irradiate the material e.g. 1 mm 
on the other side of the divisional line in order to take into account the 
inaccuracy of the separating means. If the apparatus alters between 
positive and negative images, care should be taken to alter the 
irradiation close to and on the other side of the divisional line. 
Naturally, in order to be able to use all of the section introduced in the 
apparatus, the irradiating means are most preferably capable of 
irradiating substantially all of the layer of the section containing the 
photosensitive substance, 
Apparatuses of the present type may just output the irradiated section for 
development and final use at another location. However, at present it is 
preferred that the apparatus further comprises developing and drying means 
for receiving, developing and drying the separated, irradiated section, 
and that the guiding means in their second position are adapted to guide 
the section toward the developing means. 
Including development means in the apparatus provides an apparatus which 
outputs irradiated, developed and dried sections which have the desired 
dimensions and which are, thus, ready for the end use in e.g. a printing 
machine. Thus, the only manual handling required, if any at all, will be 
the transfer of the final product of the present apparatus to e.g. the 
printing machine. 
In typical developer sections for materials of the most common type, the 
materials are transferred at a constant, relatively low velocity in order 
to ensure an even and desired development of the material. However, as 
transfer of materials in irradiating apparatuses is merely performed in 
order to transport the material from one position to another, the velocity 
of this transfer may be chosen higher and maybe less even than in 
developer sections, in order to speed up the overall processing time of a 
section in the irradiating apparatus. 
Thus, it is preferred that said moving means comprise means for 
transferring the section with a first velocity and that said developing 
means comprise means for transporting the section at a substantially 
constant second velocity being smaller than said first velocity. 
In order to ensure that the irradiated section does not prevent the 
introduction of the next section into abutting engagement with the 
supporting device, said developing means and said guiding means preferably 
interact so as to contain at least part of said section before and during 
introduction thereof into said developing means. Thus, "buffer"-means are 
preferably provided which hold the irradiated section so that the guiding 
means may be shifted to their first position in order to facilitate 
feeding of the next section into the supporting device. 
In this manner, the rather slow development of an irradiated section may be 
performed while the next section is fed and irradiated. This feature 
removes a potential "bottle neck" as it facilitates parallel processing of 
the two operations in order to speed up the overall processing time of a 
section. 
Naturally, the present apparatus preferably comprises storing means for 
holding at least a part of the length. These storing means preferably 
comprise sensor means for sensing the end of said length held in the 
storing means. 
Preferably, more than one storing means is provided in order to either hold 
materials with different widths in order to facilitate shifting between 
these widths depending on the sizes of the images or in order to 
facilitate night runs, where a large number of sections are produced 
without requiring an operator to provide the apparatus with new material. 
In some prior art apparatuses, the last part of a length of material may 
cause clogging and, thus, malfunction of the apparatus if introduced in 
the apparatus. Usually, this clogging occurs when a small piece of 
material is introduced in an apparatus where the distance between two sets 
of rollers or the distance between two guiding elements is larger than the 
size of the piece. In this situation, the guiding system of the apparatus 
will not be able to guide the piece, whereby it will remain in the guiding 
path of the apparatus. 
This may be prevented, if the above-mentioned sensor means are used to stop 
the feeding of the length at a point where the length may still be e.g. 
re-introduced into the storing means for the operator to remove when 
replacing the empty roll of material. This is especially important if e.g. 
night runs are performed for large periods of time without operator 
assistance. 
As the present apparatus preferably provides irradiated, developed sections 
ready for use, the apparatus is preferably able to function properly when 
positioned along side e.g. a printing machine. However, as a printing 
machine may generate vibrations which may interact with the very sensitive 
optics and positioning inside the irradiating apparatus, the present 
apparatus is preferably made stable to vibrations of this type. 
Thus, the supporting device, the feeding means, the moving means, the 
irradiating means, the guiding means and the storing means of the present 
apparatus are preferably rigidly interconnected and vibrationally damped 
in relation to the rest of the apparatus. 
When rigidly interconnecting these parts of the apparatus, it is ensured 
that no movement occurs therebetween. Movement between two of these parts 
may stress the sheet-like material or transfer vibrations to the sensitive 
parts of the apparatus. 
At present, the vibrational damping is obtained using rubber elements 
having a size of e.g. a diameter of 30-40 mm, a height of 30 mm and a 
hardness of on the order of 40-45 shore. Naturally, the degree of 
compression will define the degree of damping of vibrations. At present, a 
compression of the above-mentioned rubber elements of the order of 1-3 mm 
is preferred in order to provide some damping while holding the rigidly 
interconnected elements sufficiently firmly in the apparatus. 
In order to ensure that the section remains in place inside the supporting 
device during irradiation, the present apparatus preferably further 
comprises means for retaining the section of sheet-like material in 
abutting engagement with the cylindrical surface part during irradiation 
thereof. 
Usually, these retaining means are vacuum means generating vacuum between 
the sheet-like material and the supporting device. However, also other 
means may be used, such as means abutting the material in order to force 
it against the supporting device or other means capable of performing this 
task. 
In order for the apparatus to be able to produce a large number of 
irradiated sections, it preferably comprises outputting means which are 
able to hold the produced sections. In addition, these sections should be 
suitably stacked in order to remain in place during e.g. a night run. 
Thus, the present apparatus preferably comprises means for outputting the 
irradiated section from the apparatus, said outputting means comprising 
means for translating said irradiated section during outputting, means for 
detecting the rear end of the section during translation thereof, and 
accelerating means for increasing the translation velocity of the section 
during outputting of at least the rear end of the section of sheet-like 
material. 
This acceleration of the last part of the section will ensure that the 
sections are suitably stacked. 
In a second aspect, the present invention relates to a method of 
irradiating a section forming an end portion of a length of a sheet-like 
material comprising a layer containing a photosensitive substance, the 
method comprising: 
feeding the section in a first direction into abutting engagement with a 
concavely curved, substantially circular cylindrical surface part in a 
position in which the section extends peripherally along the cylindrical 
surface part, 
irradiating at least part of the layer of the section containing the 
photosensitive substance, 
moving the length of sheet-like material in a direction substantially 
opposite to the first direction to a separating position, 
separating the irradiated section from the rest of the length of sheet-like 
material, and 
removing the separated, irradiated section of sheet-like material from the 
separating position. 
Also this second aspect may be split up into the two above-mentioned setups 
characterized by the interchanged first and second directions. 
As described above, the first setup is the presently preferred setup. In 
this setup, it is preferred that the moving step only brings said section 
of sheet-like material partially out of engagement with the cylindrical 
surface part, that the separation step is performed while part of the 
section is still in abutting engagement with the cylindrical surface part, 
and that the removal step brings the section out of abutting engagement 
with the cylindrical surface part. 
As described above, the shorter the paths the section is moved, the shorter 
time is used for this procedure. 
As also described above, in this preferred setup, guiding means are 
preferably provided being adapted to guide the length and to shift between 
a first and a second position, where the guiding means are in the first 
position during the feeding step, the irradiation step, the moving step, 
and the separation step and are shifted to the second position subsequent 
to the separation step and prior to the removal step. 
These guiding means help speeding up the procedure as they may provide the 
fast removal of the irradiated section from the path required in order to 
feed the next section into abutting engagement with the supporting device.

In FIG. 1, a presently preferred embodiment of an internal drum image 
setter 2 is illustrated. This image setter comprises two compartments 4, 6 
for storing two spools 8, 10 holding the sheet-like material to be 
illuminated. The spools 8, 10 may hold sheet-like material having the same 
or different widths and/or thicknesses, in order to provide a versatile 
instrument 2. 
In the present image setter, the first part of a length of sheet-like 
material is illuminated and subsequently separated from the rest of the 
length of material. The advantage of the present image setter is the fact 
that the illuminated part of sheet-like material may be illuminated to all 
four edges thereof, whereby subsequent manual handling thereof is 
unnecessary in order to adapt the illuminated sheet-like material for e.g. 
a printing machine and a waste of material between two irradiated images 
is avoided. 
Feeding the sheet-like material from the spool 8 into position in the 
internal drum 12 is achieved (see also FIG. 2) using pairs of rollers 14, 
16, 18 and 20 together with guides 22, 24, 26, 28, 30, 32 and 34 and 
helping roller 36. Having fed the front part of the sheet-like material 
into position, the part of the sheet-like material to be illuminated is 
fixed in the drum 12 by means of vacuum generated between the drum 12 and 
the sheet-like material using a suction unit 38 in a manner known per se. 
Illumination of the sheet-like material will be described further below. 
In instruments of the present type, care should be taken when contacting 
the sheet-like material in order to transfer this through the instrument, 
as the photosensitive emulsion applied to one side of the material may 
easily be damaged due to wrong handling thereof. 
The pair of rollers 14 is, thus, presently driven by a motor (not shown) 
through a toothed belt 40 which engages the roller 14' of the pair of 
rollers 14. The other roller 14" is preferably driven by the roller 14' 
via toothed wheels (not shown) and gently pressed against the roller 14' 
by means of a biasing spring (not shown). Using a setup of this type, the 
sheet-like material and the emulsion thereon is merely gently compressed 
when fed between the rollers. A less preferred alternative to the 
above-mentioned setup is a setup where only the roller 14' is driven by 
the motor means (not shown) and where the roller 14" is firmly pressed 
against the roller 14' in order to ensure engagement between the 
sheet-like material and the driving roller 14'. In this alternative setup, 
the sheet-like material and the emulsion thereon is unnecessarily 
stressed. 
A similar setup may be seen in the pairs of rollers 16 and 18, where the 
rollers 16' and 18' are driven by motor means (not shown) via a toothed 
belt 42. 
Feeding sheet-like material from the spool 10 to the drum 12 is, in a 
similar manner, performed using the pair of rollers 44, guides 46 and 48 
and part of the guiding means described above, i.e. pairs of rollers 18 
and 20 as well as guides 26, 28, 30, 32 and 34. 
Illumination of the sheet-like material is performed, as it is known per se 
using a carriage moving along a linear track (not shown) and on which a 
laser and suitable optical elements are positioned as well as a rotatable 
mirror, which directs the laser light onto the photo sensitive substance 
of the sheet-like material. 
An illumination means or carriage 180 of this type is illustrated on FIG. 
3, where it comprises a laser 182 positioned on a base plate 184, lenses 
196, 198 and 300, a rotatable mirror 302 and a motor 304 for rotating the 
rotatable mirror 302. 
In addition, variable irises are preferably used to define the spot size of 
the radiation on the material. Furthermore, optical filters are used for 
coarsely defining the intensity of the radiation on the material. Fine 
adjustment (a factor of 2-3) may be accomplished by controlling the laser 
itself. 
Illumination of the photo sensitive substance is consequently performed by 
rotating the rotating mirror 302, modulating the laser 182 and translating 
the carriage 180 in a manner so that the rotating mirror 302 translates 
along the symmetry axis of the substantially circular cylindrical surface 
of the drum 12 in order to have the same focused laser beam on all parts 
of the illuminated material. 
In order to be able to precisely position the illuminated sheet-like 
material during a subsequent process, wherein this material forms the 
basis of e.g. a printing process, it is preferred to provide registering 
notches in the sheet-like material, which notches are precisely positioned 
in relation to the illuminated image. 
Providing these notches is preferably performed while the sheet-like 
material is in the illumination position and, thus, in connection with the 
illumination thereof and most preferably before illumination cf. below. 
In the present instrument 2, the sheet-like material is preferably fed into 
the drum 12 in a manner so that a part thereof extends beyond a side of 
the drum 12 in a direction parallel to a longitudinal axis thereof. Thus, 
part of the sheet-like material extends beyond the drum 12, whereby this 
part of the material is free for the engagement of notch providing means 
200 which may engage with the sheet-like material without interfering with 
the drum 12. 
As is illustrated in FIG. 4, the notch providing tools 200 comprise a base 
part 202 and a movable part 204 between which a gab is defined wherein the 
sheet-like material is introduced before making the notch. By operating a 
motor 206 which through a worm gear 208 and an eccentric 209 translates 
the movable means 204 from its first position illustrated in FIG. 4 to its 
second position, wherein it is submerged in the base means 202, and back, 
indentation of the sheet-like material is performed. 
One center axis of the eccentric 209 is connected to the movable part 204 
and the other center axis of the eccentric 209 is connected to the worm 
gear 208. 
The movement of the movable means 204 is monitored by monitoring means 210 
in a manner which will be described below. 
The base part 202 is fastened to the apparatus along an axis C. Due to the 
movement of the eccentric 208, the motor 206 may rock during the provision 
of the edge portion. In fact, the movement of the motor 206 and eccentric 
208 is the movement detected by the monitoring means 210, as this means is 
positioned so as to detect movement between the base part 202 and the 
eccentric 208. 
The movement of the motor 206 is, due to the position of the eccentric 208, 
into and out of the plane of FIG. 4 and is monitored by the means 210, 
which detects the movement 90.degree. out of phase with the movement of 
the movable part 204. 
Thus, the means 210 is activated when the movable means 204 moves from the 
first position to the second position--that is, during provision of a 
registering edge portion--and deactivated during the opposite movement. 
The means 210 shifts its mode, when the moving means 204 is in its first 
and second position. 
Using a means 210 in this manner, only a single means is sufficient for 
monitoring the movement of the moving means 204. 
In order not to deform the sheet-like material during indentation thereof, 
the stationary means 202 preferably comprise a support surface 220 on 
which the sheet-like material may rest during indentation. Preferably, 
this surface 220, into which the movable means 204 are received subsequent 
to indentation of the sheet, has an edge 222 fitting the indenting edge 
224 of the means 204. In this situation, only the part of the sheet 
closest to the position of indentation is influenced (and, thus, has a 
small risk of deformation) by the indentation. 
As described above, it is preferred to be able to illuminate all parts of 
the sheet-like material. Thus, it is desired not to have any kind of 
shadowing elements positioned over the sheet-like material during 
illumination thereof. Thus, it is preferred that, subsequent to 
indentation, no part of the indentation or notch providing means 200 to 
any substantial degree extend beyond the plane of the sheet-like material 
positioned on the surface 220. 
As may be seen from FIGS. 4 and 5, the moving means 204 and the stationary 
means 202 are manufactured so that the moving means 204 may be introduced 
completely into the stationary means 202 so as to not project above the 
support surface 220 of the stationary means 202. Thus, no part of the 
indentation means 200 may provide shadows during illumination of the 
sheet-like material. 
The axial positions of the indentation of the sheet-like material may, 
naturally, be adapted to the individual needs or requirements the 
operator. However, at present, a rectangular indentation and an 
indentation as illustrated in FIG. 5, where parts of the outer contour of 
the movable means 204 comprise an edge portion defining part of a circle, 
are provided. These indentations help in positioning the illuminated 
sheet-like material in e.g. a printing machine. 
A widely used European industry standard requires a distance between the 
two indentations of 220 or 425 mm and that these indentations be 
positioned symmetrically about the middle of the sheet-like material. 
Thus, it may be required to provide either multiple indentation tools 200 
or that one or more of these tools be movable so as to be able to each 
produce multiple indentations. 
In FIG. 6, two indenting tools 200 are illustrated positioned at the 
periphery of the drum 12. In the present invention, it is preferred that 
the tools 200 are positioned symmetrically along the total periphery of 
the drum 12. In this manner, the tools 200 may provide indents in a 
material having the maximum size possible in the apparatus. 
When introducing smaller pieces of material, this material is preferably 
positioned in the drum 12 so that the middle of the material is positioned 
at the middle of the periphery of the drum 12. In this manner, the indents 
are positioned symmetrically along the side of the material independently 
of the dimensions thereof. 
However, providing e.g. four tools 200 facilitates providing the two 
notches with the two different distances of a widely used European 
industry standard without having to move the means 200 or the sheet-like 
material between the indentations of the sheet-like material. 
When moving the tools 200 between two positions, each indenting means 200 
may, alternatively, produce two indentations in the plate-like material. 
This provides the use of also other indenting standards in the present 
apparatus or the use of only a single tool 200. 
An alternative apparatus will be one in which movable tools 200 or more 
than two thereof are provided in order to make the instrument more 
versatile so as to be able to accommodate different lengths of sheet-like 
material. This may, naturally, be highly preferred, when the length of the 
sheet-like material is often changed. 
Subsequent to illumination of the front part of the sheet-like material, 
this material is removed from the drum 12 using at least the pairs of 
rollers 18 and 20 in the manner described hereinafter: 
The sheet-like material is withdrawn from the drum 12 along the same path 
as that along which it was introduced from the spool 8 or 10 to a position 
where a cutting wheel 100 may separate the desired part of the sheet-like 
material from the rest of the length thereof--see FIG. 2. 
Thus, by not cutting the sheet-like material until after illumination 
thereof, the full area of the part of the sheet-like material may be 
illuminated. A problem arises when the full area of a piece of material is 
to be illuminated to all four edges, as, during illumination, nothing can 
contact the upper surface to be illuminated thereon; any contact thereon 
may cause shadows to be formed in the illuminated image. This problem is 
solved in the present image setter due to the fact that the illuminated 
part of the sheet-like material is not separated from the rest of the 
length thereof until subsequent to the illumination thereof. Thus, during 
illumination, the rest of the length of sheet-like material may act as a 
"handle" with the aid of which the illuminated part of the sheet-like 
material may be removed from the drum 12. 
Subsequent to illumination thereof, the sheet-like material is partly 
withdrawn from the drum 12 and the desired part of the sheet-like material 
is separated from the rest of the length thereof using the cutting wheel 
100. In FIG. 2, the cutting wheel 100 is adapted to move into and out of 
the plane of FIG. 2 and to have a resting position, where it is out of 
engagement with the sheet-like material being fed or withdrawn. 
In the present embodiment 2, the cutting wheel 100 is rigidly connected to 
a member 102 toward which the guide 34 is gently forced during feeding or 
removal of the sheet-like material. During cutting of the sheet-like 
material, the guide 34 is slightly displaced so as not to engage the body 
102 during its movement into and out of the plane of FIG. 2. 
Cutting of the sheet-like material is performed by moving the cutting wheel 
100 into or out of the plane of FIG. 2 when the sheet-like material has 
been brought into position, i.e. where the desired cutting edge is 
positioned between the cutting wheel 100 and an opposite member 104 at the 
opposite side of the sheet-like material. 
At present, rotation of the cutting wheel 100 is provided due to a friction 
member 106 positioned on the cutting wheel 100 and contacting the guide 
30. Due to the engagement between the friction member 106 and the guide 
30, the cutting wheel 100 will rotate when moved into and out of the plane 
of FIG. 2. Preferably, in order to help fix the sheet-like material during 
cutting, the lower part of the guide 30 is flexibly mounted so as to be 
forced against the sheet-like material positioned between the guide 30 and 
the opposite member 104 during cutting. As the material is stationary 
during cutting, substantially no damages will occur at the surface 
thereof. 
Subsequent to cutting, the cut-off part of the sheet-like material having 
been illuminated is to be transferred to a developer section 110 (see FIG. 
1) for development. This transfer is achieved by shifting the guides 32 
and 34, which are rigidly interconnected, to a position illustrated by 
broken lines in FIG. 2 (34' and 32'), whereby the cut-off part of the 
sheet-like material may be guided by guides 112, 114, 116, 118 and 120 
(see FIG. 1) as well as pairs of rollers 20, 122 and 124 into the 
developer section 110, which is known per se and will not be described in 
detail. 
The movement of the guides 34 and 32 between the positions where the guide 
34 is gently forced against the member 102, i.e. the feeding position, 
where sheet-like material is fed into the drum 12, the position cutting 
where there is no engagement between the guide 34 and the member 102, and 
the position 34', i.e. the position for removing the sheet-like material 
from the drum 12, is controlled by an eccentric member 126, against which 
the guides 34 and 32 are spring loaded, and which is moved by a step motor 
(not shown). 
The rotation of the eccentric member 126 and, thus, the position of the 
guides 32 and 34 is monitored by a switch 128 which is positioned so as to 
detect the position 126" illustrated in FIG. 2, i.e. a position where the 
guides 32 and 34 are close to the removal position. Having detected this 
position 126", it is a matter of simple calibration to determine the 
number of steps taken by the step motor (not shown) in order to bring the 
guides 32 and 34 into the cutting or feeding positions, respectively. The 
position 126"" is the cutting position, position 126' is the feed position 
and the position 126'" is the removal position. 
In order to provide a fast instrument capable of illuminating a large 
number of "images" it is required to remove the illuminated part of the 
sheet-like material as fast as possible in order to be able to introduce 
and illuminate the new front part of the sheet like material in the drum 
12. 
This may be counteracted by the fact that, usually, the velocity of the 
sheet-like material in the developer section 110 should be constant and 
quite low. Thus, in order to still be able to quickly remove the 
illuminated part of the sheet-like material from the drum 12, a buffer is 
provided to hold the sheet-like material during introduction thereof into 
the developing section 110 and in order to facilitate fast introduction of 
the new front part of the sheet-like material in the drum 12. 
This buffer is provided between pairs of rollers 122 and 124 in the manner 
described below: 
In the developer section 110, all pairs of rollers are connected to the 
same motor means (not shown) so that the movement of the sheet-like 
material in the developer section 110 is constant and well-defined. Thus, 
the pair of rollers 124 will engage with an introduced sheet-like material 
and provide it this velocity. However, in order to quickly remove the 
sheet-like material from the drum 12, the velocity provided by the pair of 
rollers 122 is preferably higher. Thus, providing the guide 116 in a 
manner so that it may rotate, the surplus of sheet-like material 
introduced between the pairs of rollers 122 and 124 (see broken line 115 
in FIG. 1) forcing the guide 116 from a more horizontal position (as seen 
in FIG. 2) to a more vertical position (as seen in FIG. 1. 
During operation of this buffer, it is preferred that the pair of rollers 
122 holds the axially trailing end portion of the sheet-like material 
while the pair of rollers 124 introduce the front part of the sheet-like 
material into the developing section 110. This is presently accomplished 
by providing an edge detecting sensor 128 comprising e.g. a light emitter 
emitting light on to the back side of the sheet-like material and a light 
detector positioned so as to receive light reflected from the back side of 
the sheet-like material. This sensor 128 will be able to detect the 
presence of the farthest edge portion of the sheet-like material, 
whereafter it is simple to stop the rotation of the pair of rollers 122 
when this edge portion is close thereto. It is furthermore preferred that 
the engagement between the pair of rollers 122 and the sheet-like material 
is so loose that no damage is incurred on the sheet-like material, when 
the buffer is emptied and the pair of rollers 124 "pulls" the sheet-like 
material out of engagement with the pair of rollers 122. 
In the present embodiment, the pair of rollers 20 is preferably driven by a 
toothed belt 130 by motor means (not shown) and the pair of rollers 122 is 
driven by another toothed belt 132 by the same motor means (not shown) and 
via the pair of rollers 20. It is also preferred that the engagement 
between the toothed belt 132 and the pair of rollers 20 is a type where no 
torque is transferred to the pair of rollers 122, when the pair of rollers 
20 is rotated so as to feed sheet-like material into the drum 12. Torque 
should only be transferred to the pair of rollers 122, when the pair of 
rollers 20 is rotated to as to remove sheet-like material from the drum 
12. 
After the development section 110, the developed sheet-like material is 
dried in a drying section 134 where two driers 136 and 138 apply drying 
air to both sides of the sheet-like material through guides 140 and 142, 
which are preferably made of e.g. a metal grid in order to provide access 
for the drying air to the developed material. 
Subsequent to drying, the material is transferred to an exit section 144, 
where the material is transferred between two pairs of rollers 146 and 148 
in each of which one roller is driven by a motor 150 by means of a belt 
152. In order to stack the illuminated and developed pieces of sheet-like 
material, the motor 150 is preferably accelerated when transferring the 
last part of the sheet-like material from the drying section 134 to the 
exit section 144 along arrow A. 
In order to provide a very versatile instrument, the sections 4 and 6 and 
the pertaining spools 8 and 10 are preferably able to hold and feed 
sheet-like material having different widths and/or thicknesses into the 
drum 12. Furthermore, the fact that more than one spool of material may be 
introduced will enable the instrument to illuminate a large number of 
images unattended such as during the night. However, in order to ensure 
that the instrument is able to perform a large number of illuminations 
without having to be attended by an operator, it is highly preferred to 
have a strict control with the translation of the sheet-like material in 
the instrument. Thus, especially when e.g. having to withdraw sheet-like 
material from the spool 10 back into compartment 6 in order to feed new 
material from the spool 8 in the compartment 4, it is crucial that the 
position of the front edge portion of the sheet-like material on the spool 
10 is determined in order to maintain engagement therewith by the pair of 
rollers 44 in order to be able to subsequently again feed material from 
the spool 10 when required. 
To this effect, two sensors 160 and 162 (see FIG. 2) of the same type as 
the sensor 128 are provided in order to detect the front edge portions of 
the material from the spools 10 and 8, respectively. Having detected the 
front edge portion of the material from one of the spools with the 
corresponding sensor, the movement of the motor means (not shown) driving 
the pairs of rollers 14 or 44, respectively, required in order to remove 
the sheet-like material but to retain engagement thereof with the pair of 
rollers 14 or 44, respectively, may easily be determined. 
Additionally, in typical instruments of this type, it may cause severe 
problems when the sheet-like material from the spool runs out and is 
thereby introduced into the guiding system of the instrument. This problem 
is in some instruments solved by simply not cutting the last illuminated 
part of the sheet-like material into the correct dimensions and, thus, 
simply transferring this larger piece of sheet-like material through the 
system. However, this is not desired as, consequently, part of the 
illuminated images will, thus, still require manual attention and adaption 
to the desired dimensions. 
In the present embodiment, this problem is solved by detecting the farthest 
edge portion of the material on the spools 8, 10, respectively, using 
sensor means 164 and 166, respectively, each comprising a light emitter 
and a light detector positioned on either side of the sheet-like material, 
the fact that the light detector may detect light from the light emitter 
means that the farthest edge portion of the sheet-like material on the 
respective spool has passed between the sensor means 164 or 166 and is 
close to the pairs of rollers 14 or 44, respectively. In the present 
embodiment, this will stop the motor means (not shown) driving the pair of 
rollers 14 or 44 and optionally additionally pairs of rollers 16, 18 and 
20 in order to ensure that this last part of the sheet-like material is 
not transferred into the system. At present, it is preferred to simply 
withdraw the rest of the sheet-like material back into the compartment 4 
or 6 in order for the operator to remove this part of the material when 
replacing the corresponding empty spool 8 or 10. 
Even though the above-mentioned embodiment, wherein it is ensured that all 
illuminated pieces of sheet-like material are cut to the correct 
dimensions and that all any remaining parts of the sheet-like material is 
transferred back to the respective compartment, this embodiment has a 
disadvantage. This disadvantage is the fact that the remaining part of the 
sheet-like material transferred back into the respective compartment 
cannot be used and is, thus, considered as waste. The amount of waste is, 
naturally, the largest from compartment 4 due to the longer path therefrom 
to the drum 12. In order to reduce this amount of waste, the 
above-mentioned embodiment may be altered so as to adapt the guides and 
the pairs of rollers therein so that these elements are able transfer a 
certain length of sheet-like material from the cutting means and back into 
the respective compartment 4 or 6. In this manner, the back edge portion 
of the sheet-like material may be brought out of engagement with the pairs 
of rollers 44 or 14 so that yet another part of the sheet-like material 
may be used in the instrument. Having illuminated the front part of the 
rest of the sheet like material, the material is cut as described above 
and the last, small part of the sheet-like material may, then, be 
transferred back into the respective compartment 4 or 6. 
In this embodiment, the controlling electronics (not shown) will be able to 
calculate, on the basis of the length of sheet-like material having been 
introduced in the drum 12 when the respective edge sensor 160 or 162 
senses the farthest edge portion and the length of material between the 
respective sensor 160 or 162 and the drum 12, whether there is sufficient 
sheet-like material for the image, and whether the remainder of sheet-like 
material may be transferred back into the respective compartment. Should 
this be the case, the sheet-like material may be brought out of engagement 
with the respective pair of rollers 14 or 44 and the introduction of 
material into the drum 12, the illumination thereof and the cutting may be 
performed as usual. Subsequent to cutting, the rollers and guiding means 
of the instrument will then transfer the remainder of the sheet-like 
material back into the compartment for the operator to remove and replace 
with a new spool of sheet-like material. 
At present, no positioning or correction of the sheet-like material in the 
direction into and out of the plane of FIGS. 1 or 2 is required if care is 
taken in the instrument not to stress the material. However, as the 
instrument may be positioned on heavily vibrating floors, such as beside a 
printing machine, it is presently preferred to position those parts of the 
instrument which are more sensitive to position displacements on resilient 
means, such as pieces of rubber, in order to reduce the influence of 
vibrations. 
Thus, at present the compartments 4 and 6 and the guides and rollers for 
transferring the sheet-like material into the drum 12 as well as the drum 
12 and the illumination carriage 180 are rigidly interconnected and 
positioned on resilient means 170 and 172. The advantage of rigidly 
interconnecting the compartments 4 and 6, the drum 12 and the carriage 180 
and isolating these parts from the surroundings is obvious, since 
movements between these elements will introduce precision instabilities in 
the instrument, as the precision of the introduction and, thus, the 
position of the front part of the sheet-like material in the drum 12 will 
be reduced.