GB1564339A - Apparatus for recording texts on a record carrier - Google Patents

Description

(54) APPARATUS FOR RECORDING TEXTS ON A RECORD CARRIER (71) We, IIAATSCHAPPH VAN BERKEL'S PATENT N.V., a Dutch Company of 5 Keileweg, Rotterdam, The Netherlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to apparatus for recording texts on a record carrier.

According to the present invention there is provided apparatus for recording texts on a record carrier, comprising means for moving a record carrier through a recording zone at which there are located first and second text sources, said text sources being disposed at opposite sides of the carrier and being provided with character script for recording characters on the record carrier, one of the text sources being adapted to record characters on the record carrier from the front thereof and the other text source being adapted to record characters on the record carrier from the rear thereof so as to be readable from the front.

An embodiment discloses an apparatus for recording on a record carrier alphanumerical data and/or machine-readable code marks of an information converter. The text source, for which a printer can be used, comprises in the region of its recording zone along which the record carrier is moved, a set of given characters, e.g. the types of a printer, and a character selector which sets for printing the characters needed at the moment from the set of characters. In a parallel printer operating with flying impression wherein a drum rotating at high speed comprises a full character set for each position of the recording zone, the aforesaid character selector consists of an impression hammer which imprints the desired character on the paper.The character selector, such as an impression hammer of this kind, is controlled by a device for detecting measured values, preferably consisting of a weighing machine.

The record carrier can consist of the sales label of the merchandize, but the wrapping of the merchandize itself could also serve as record carrier. In any case, the record carrier is moved along a recording station where the desired data are recorded. These data may consist, on the one hand, of individually variable data such as the weight determined and the accordingly calculated unit price of the merchandize weighed, and on the other hand also comprises fixed data, such as the designation of the article and its durability.

Among the disclosed processes used for recording data there is also a method where the information converter consists of an electro-optically controllable liquid-crystal cell wherein the character set is given by the appropriate profiling of its electrodes and where the desired character is made visible in the light passing through the liquid-crystal cell by individually addressing the electrode profile segments concerned. To achieve higher contrast in this type of visualisation polarizing foils are used as polarizer and analyzer in front of and behind the liquidcrystal cell. Photographic paper, in whose place zinc oxide paper can also be used, photosensitized by electrostatic charging, serves as the record carrier. Photosensitive selenium layers can also serve as transfer medium.

In known apparatus it is difficult to achieve on the record carrier a high density of data applied simultaneously and not successively line by line or even individually.

If a printer is used as the information converter, the rotary drum carrying the types requires some lateral space at the recording spot of this information converter, so that several lines can only be imprinted simultaneously on a record carrier by a multiple arrangement of such drums and impression hammers when a sufficiently large line spacing is provided. Similar difficulties occur with information converters in the form of liquid-crystal cells. The simultaneous recording of numerous characters on the record carrier requires for the individual control of a correspondingly large number of profiled electrodes a large amount of space for the array of electrode leads and a large longitudinal dimension at the edge of the liquidcrystal cells for the individual electric terminals.This is because for technical reasons, the dimensions of the terminal leads should not be smaller than about 0.05 inches. As a result, the characters to be copied simultaneously on a record carrier must here also be arranged at larger distances one from the other when more than about one line is foreseen in the recording zone.

In the case of labels carrying the sales data of an article, which must be marked not only with the weight and unit price, but also with the price per unit weight, packing date, durability, several lines must be inscribed in the recording zone of the label.

To save time, all characters should of course be recorded simultaneously. In known equipments it was possible to mark such labels as a rule only if the data were recorded on the record carrier successively in several stages, which is uneconomical.

For the constructional reasons explained above, a large character spacing or line spacing was needed when all the required characters had to be simultaneously recorded on the record carrier. This resulted in the need for record carriers of large dimensions.

However, large record carriers require much material, are cumbrous in handling and difficult to read. It is hardly possible to use such large record carriers as sales labels for marking articles.

The present invention enables numerous characters to be recorded substantially simultaneously and in a small area of the record carrier by dividing the information converter into two text sources situated in the recording zone at opposite sides of the record carrier, the two sources being provided with characters in mirror-inverted relationship and acting together to effect the recording, the record carrier being transparent up to its common display face to the character pulses of the one part applied from the rear.

It is possible to utilise the space above the record carrier for one text source and the space below it for the other text source.

Since the two text sources are situated at opposite sides, they do not hinder each other as far as space requirements are concerned.

It is therefore possible to bring the recording areas of the one source close enough to the recording areas of the other source to ensure a considerable increase of the recording density. The division into two sources enables the number of printing spaces provided in each source for the individual characters to be utilised up to the technical limit so far attained by a single information converter. As can be seen, this makes it possible to practically double the information density of the characters becoming simultaneously affective for recording. The arrangement described above necessitates the character script of the two parts to be in mirror-inverted relationship. Since the characters of both parts are recorded concurrently, a rapid marking of the record carrier is possible.The characters recorded from the rear appear, just as the characters applied from the front, in the joint reading surface of the record carried since this is made transparent to the character pulses applied from the rear. The final result is that both the characters applied from the front and those applied from the rear are easily readable from the same side of the record carrier.

There are various possibilities of designing the information converter, each of which has its particular advantages. Details will appear from the following description and the drawings. When employing an information converter in the form of a liquid-crystal cell with a record carrier consisting of photographic paper, it is advantageous to use both the front of the photosensitive layer and the rear, support side of the photographic paper as image-receiving planes for the characters. These characters come from two projectors, each of which is on a different side of the photographic paper.

Both are recorded in the photosensitive front layer since, the support layer of the photographic paper is made transparent to the light from the projector incident from the rear. The image fields of the two projectors do not overlap since they cover different areas of the photographic paper which supplement each other in the joint recording zone. This enables the available recording zone, to be fully utilised reprographically over its whole area, avoiding the recording of incompatible, mutually obstructive information. A label or package can thus be marked with the full sales data for an article within fractions of a second.

This makes it possible to mark goods with sales labels at the speed at which the weighing equipment can determine the weight of successive batches.

Since the pricing of goods often comprises a set of fixed data and only part of the data is individually variable, it is advisable to assign the data to the two parts of the information converter in this sense. The part for the variable data is placed at the one side, the part for the remaining, fixed data is located at the opposite side of the record carrier. The advantage of this arrangement is that the type of information converter can be better adapted to the different data. Thus, a liquid-crystal cell can be used as the part for the variable data, whereas a transparency bearing the fixed data and acting as a slide is suitable for use as the other part. For a pricing label, this transparency can bear data relating to the firm, the category of goods, the packing machine, etc.In this case the transparency is exchangeably held in a mounting, disposed in the path of rays of the corresponding projector.

Two embodiments of the invention will now be described by way of example with reference to the drawings, in which: Fig. 1 is a schematic view of an assembly according to the present invention, partially in cross-section; Fig. 2 is a view of a detail of Fig. 1 illustrating a first embodiment; Fig. 3 is a highly magnified cross-section, not to scale, through one part of Fig. 2; Fig. 4 is a plan view of a part of Fig. 3; Fig. 5 is an example of a sales label for goods, produced by means of the assemblies of Fig. 1; and Fig. 6 is a second embodiment of the detail illustrated in Fig. 2.

The assembly shown in Fig. 1 comprises a data recording device 10 and a weighing machine 11 which ascertains the critical measured data for the device 10. The weighing machine 11 is disposed in the path of a line of articles illustrated as packages 12, 12', 12". When a package 12' arrives in the course of this motion on the balance pan 13 of the weighing machine 11, the weight 14 acting as a load in the direction of the arrow is ascertained and transmitted in the form of an electrical pulse via a control line 17 to the recording device 10. The balance pan 13 is situated between the ends of two conveyors 15, 16. Furthermore, an input unit 20 adjustable via a keyboard 19 for forming characters in the recording device 10 is connected to the latter via an additional control line 18.The keyboard 19 of the input unit permits a fixed text to be produced in the recording device 10, independent of the weight data 14 every time ascertained by the weighing machine 11. The preset fixed text can be checked in the reading window 21 of the input unit 20.

The variable measured values of the weight 14 on the one hand and the preset fixed values of the input unit 20 on the other hand are transmitted to an information converter in the device, divided into two parts 22, 23 which form text sources. In the present case, the variable data are trans mitted exclusively to the part 23, while the preset fixed data are applied to the other part 22, as can be gathered from the course of the two control lines 17, 18. In the present embodiment, recording is performed photographically. The parts 22, 23 of the information converter are transilluminated by light sources 24, 25 whose path of rays is guided by schematically illustrated optical means of projectors 26, 27. The rays from the projectors strike a record carrier 28 consisting in the present case, as a matter of course, of photographic paper.A zinc oxide paper is used by preference, made photosensitive by electrostatic charging before it enters the path of rays of the projectors 26, 27. Details of the image production will be described in detail later.

The exposed areas of the photographic paper are discharged so that a latent charge image is produced. The charge image is transformed into a visible image in a subsequent toner station 29 illustrated in Fig. 1 merely schematically, the toner particles being deposited in the charged areas, or repelled by them and deposited in the discharged areas. They are then permanently fixed there.

In the present case, the record carrier 28 consists of a continuous line of sales labels.

When the weight of the package 12' shown in Fig. 1 is ascertained by the weighing machine 11, not only the unit weight but also the selling price is thereby determined, with the aid of a calculator inserted in the equipment, into which the price per unit weight has been entered. These data appear in the one part 23 in a manner to be further described in detail. If there is sufficient space, further data such as the price per unit weight, packing date, durability, designation of the goods etc., can be inserted either in this part 23 of the information converter or in its afore-cited other part 22. The data appearing in the two parts 22, 23 of the information converter are simultaneously projected onto a portion of the record carrier 28, designated as the recording area 30 of the information converter 22, 23.This portion forms the corresponding label which, after having been treated in the toner station 29, is delivered by the device 10 as a finished label.

In the present case, it is just the label 31 shown before that arrives at the corresponding package 12" which was on the weighing machine 11 during a foregoing operating cycle. It was at that moment that this label 31 was in the aforesaid recording area 30 of the information converter 22, 23. This ensures that each package 12, 12', 12" is marked with the correct label 31 individually assigned to it.

The special aspect according to the invention is that the two parts 22, 23 of the information converter lie at opposite sides of the record carrier 28, as already appears from Fig. 1. This arrangement can be discerned more clearly in the partial view of the device in Fig. 2. The critical reading surface of the record carrier 28 is only on one of its sides.

With the present photographic paper 28 this means that only the front of the paper carries a photosensitive layer 32, facing solely the part 22 of the information converter. The characters produced in the information converter 22, whose generation will be described in detail further on, are therefore projected by the corresponding projector 26 on to the photosensitive layer face 32 of the photographic paper 28. An arrangement of masks 33 of suitable form and size ensures that the projection of part 22 covers only those partial areas 34 of the entire recording zone 30 which result from the layout of the characters.

On the other hand, the second part 23 of the information converter 23 is projected on to the rear of the record carrier 28, where the photographic paper used has only a support layer 35 not sensitive to light. However, this support layer is transparent to the projection light 39 incident on the rear. The light from the rear projector 27 therefore also arrives, after transillumination of the characters provided in the part 23 and after having passed through the support layer 35, at the photosensitive layer 32 of the photographic paper where it is recorded. Suitable masks 36 make sure that the image field areas 34, already exposed by the front projection beam 38, are not exposed again by the rear projection beam 39. The image field area 40 covered by the rear projection 39 comprises the adjacent surface areas of the photographic paper 28.As shown in Fig. 2, the particular image fields of the two paths of rays from the projectors 38, 39 complement one another without a gap.

As a matter of course, those areas of the two parts 22, 23 not pertaining to the areas of the characters to be transmitted and therefore covered by the masks 33 and 36 respectively, afford space for the necessary supply lines and the like.

The connection between these matters will become clearer with reference to the embodiment shown in Figs. 3 and 4.

The type and operating mode of the information converter used here can be gathered from the cross-sectional view of Fig. 3, not drawn accurately to scale. A liquid-crystal cell serves as information converter. It consists of two end walls 42, 43 sealed at the edges which, as a matter of course, are transparent to the light of the projection beam 38, 39.

The end walls 42, 43 are spaced at a very small distance 44 one from the other.

The space enclosed in this manner is filled with a nematic substance which in the desired range of operation of the device is in the required liquid crystallinic state. The inner surfaces of the walls 42, 43 facing each other are provided with electrodes 45 on the one hand and 46, 46' and 46" on the other hand, applied to the walls by evaporation of metals. At least one of the electrodes is divided into segments 46, 46', 46" according to the different characters to be transmitted in this spot, the desired character being produced by addressing the corresponding segments. The segments are addressed electrically, simply by applying a voltage between the continuous electrode 45 on the one hand and the segments of the other electrode on the other.

In the embodiment illustrated in Fig. 3, voltage is presumed to be applied between the electrode 45 and the middle segment 46' only. A parallel orientation of the molecules of the nematic substance contained in the space 44 occurs therefore only in the region of space 47 underneath the segment 46'. In the other regions, to which no voltage is applied, the molecules remain unoriented.

For this reason the optical behaviour of the substance differs from that in the other regions of the cell which have not been addressed. The oriented substance in the region of space 47 is capable of changing the plane of oscillation of transmitted polarized light. This phenomenon is utilised for the production of characters by correspondingly addressing suitable segments 46' of the electrodes.

Fig. 3 illustrates by way of example three rays 48, 48', 48" which exhibit different behaviour owing to the presumed electrical addressing of the cell 41. The front and rear side of the cell 41 are fitted with polarisation cells. As shown schematically in Fig. 3, the incident light 48 to 48" comprises both a horizontally and a vertically oscillating component.

The front foil 50, which acts as polariser, suppresses one of the components, e.g. the horizontal one, so that only the vertically oscillating component of light can penetrate into the interior of the cell 41 as shown in the diagram of Fig. 3. A foil 51 on the light exit side of the cell serves as analyzer. It is oriented so that it suppresses the other component, in this case the vertical one. The incident rays 48, 48" pass through optically inactive regions in the space of the substance 44. The ray 48" passes through a gap between two electrode segments and therefore remains always optically unchanged in the region of the cell, whereas the ray 48 remains unchanged in the present case only because it passes through an electrode segment 46 to which no voltage is applied. As a result, the remaining oscillatory component of both rays is suppressed in the analyzer. Thus, these areas of the cell 41 appear dark in the transmitted projection ray.

On the other hand, the oscillatory component of the polarised light ray 48' undergoes an optical change in the interior of the cell 41. As illustrated in Fig. 3, there again appears a vertically oscillating component in the electrically addressed region of space 47 in the nematic substance. As a result, the vertical component of the ray 48' is also suppressed by the analyzer but the horizontal component created in the meantime is passed through, as shown by 49 in Fig. 3. The rays 49 emerging from the cell 41 is these surface areas, coacting with the areas which remain dark, result in the production of the desired character, formed by suitable electrically addressing the segments.

This light now strikes the photographic paper and generates the image as explained with reference to Fig. 2.

Fig. 4 illustrates an example of how such segments are formed in a cell to produce on the record carrier a label such as shown in Fig. 5. Let us assume that, for example, the areas enclosed by the dashed lines in the finished label of Fig. 5 are to be imaged on the label by means of a single liquid-crystal cell 41. The cell 41 is supposed to form here the one part 22 of the information converter. The remaining texts of the label are in this example assumed to be projected from the rear by the other part 23 of the information converter.

The highly magnified top view of Fig. 4 illustrates the lower portion of the liquidcrystal cell 41. Since the smallest dimension of a terminal lead is preferably of the order of 0.05 inches, the space required for the configuration of the terminal leads 52 and of the corresponding terminals in the edge region of the cell, as indicated there, is the minimum. The sixteen electrodes segments provided at the site of each individual character can also be discerned in Fig. 4.

In order to produce the digits shown in the embodiment, voltage must be applied to the terminals 53 of the cell 41 which are marked black, so that the segments shown black can be supplied with the voltage via the corresponding terminal leads 52. It will be seen that a relatively small character imaging area resulting from the configuration of the segments requires a very much larger surface area for accommodating the necessary connecting means. The latter area cannot be used for the projection of further characters. E.g., the surface region indicated in Fig. 4 by the brackets 54 is needed for the production of the digits reserved for the net weight in the label of Fig. 5. Thus, this liquid-crystal cell 41 cannot be used to produce the word "Price" in the surface area provided for it in the label.

As already mentioned, the data to be marked on the label are applied to the record carrier 28 not only from the viewing side, but also from the rear side. It is thus possible to obtain the information density illustrated in Fig. 5. The word "Price" which could not be accommodated in the cell 41 which, according to the aforementioned example, was supposed to form the front part of the information converter, can be applied by the part 23 of the information converter placed at the rear.

The part 22 mlght also consist of a separate liquid-crystal cell. This could be controlled by the keyboard 19 of the input unit 20 as already explained with reference to Fig. 1. Since, however, we are concerned in the present case with data remaining essentially constant for a large batch of articles, an information converter of simpler construction can be used for this part 22, e.g.

a transparency carrying fixed characters and/or digits. This transparency is imaged on the record carrier 28 by the corresponding front projection beam 38. The transparency is mounted in a holder not shown in detail, placed in the path of the projection beam 38. According to the category of the merchandise, a suitable transparency is used which can easily be inserted in such a holder.

Viewed against the direction of projection, the characters of the part 22 positioned on the viewing side will appear as mirror writing. In contrast, the characters of the part 23 situated at the rear of the record carrier 23, when viewed against its direction of projection, will appear normal. Thus, the character scripts in the two parts 22, 23 of the information converter are in mirrorinverted relationship.

In the second embodiment shown in Fig.

6, corresponding components bear the same reference numbers as in the preceding drawings, but distinguished by an apostrophe ('). In the present case, the two parts 22', 23' of the information converter consist of two printers situated at opposite sides of the record carrier 28' which consists here of a simple paper strip. Each of the printers 22' 23' comprises a rotating drum 56, 57 and a hammer 58, 59 the two hammers being situated at different sides of the paper strip 28', opposite the associated drum. The hammer becomes operative when the selected character of the drum 56, 57 precisely faces the paper surface. For the sake of clarity, the script 62, 63 is shown in the drawing tilted into the plane of projection, but it will be understood that the characters 62, 63 are arranged along the periphery.It will also be understood that, for several character positions lying one next to the other, the drum 56, 57 carries a plurality of rings with the characters to be printed, the rings being positioned one next to the other, and that a corresponding number of hammers 58, 59 is provided for each ring of characters. The inked ribbon 55 is dis posed on the side of the paper strip 28' facing the printer 22'.

When the hammer 58 presses against the paper, the character 62 of the drum 56 facing at that moment the inked ribbon 55 will appear on the side of the paper facing the ribbon. On the other hand, when the hammer 59 pertaining to the printer 23' situated at the rear is actuated, the profile of the character 63 on the drum 57 is pressed through the paper from the rear and is correspondingly inked on the front by the inked ribbon 55. The two printers 22', 23' may considerably overlap in height with respect to the paper strip 28', so that the print positions determined by the hammers 58, 59 can lie one close to the other and can therefore be used to imprint a joint label. After having been imprinted, the paper strip 28' is delivered in the direction of the arrow 60. Though the printers are disposed on both sides, the type face appears on a common display surface, marked 61 in Fig. 6.If the paper strip is provided with an adhesive layer at the rear which can be covered with a foil while the strip passes through the printer 22', 23', the finished label can be easily attached to the corresponding packing of the article.

As a matter of course, the invention permits information converters of different prior art design to be used for applying the data to a record carrier. The invention makes it always possible to obtain a high information density of jointly recorded symbols.

WHAT WE CLAIM IS: 1. Apparatus for recording texts on a record carrier, comprising means for moving a record carrier through a recording zone at which there are located first and second text sources, said text sources being disposed at opposite sides of the carrier and being provided with character script for recording characters on the record carrier, one of the text sources being adapted to record characters on the record carrier from the front thereof and the other text source being adapted to record characters on the record carrier from the rear thereof so as to be readable from the front.

2. Apparatus according to Claim 1, wherein each text source is in the form of a rotatable drum carrying characters in raised formation thereon, a hammer for co-operation with a selected character, and an inked ribbon intermediate the hammer and the drum.

3. Apparatus according to Claim 1, wherein each text source produces an optical image text to be printed on the record carrier, and the apparatus incorporates an electro-static charging device having opposed electrodes between which the record carrier, which has a photoconductive surface, passes prior to entering the recording zone.

4. Apparatus according to Claim 3, wherein each text source comprises a liquidcrystal cell the optical output of which is controllable by an electrical input signal.

5. Apparatus according to Claim 3.

wherein one text source comprises a liquidcrystal cell the optical output of which is controllable by an electrical input signal, and the other text source comprises a transparency exchangeably mounted in a holder.

6. Apparatus according to any preceding Claim, wherein one text source is automatically controllable to provide a variable text and the other text source provides a nonvariable text.

7. Apparatus - according to Claim 3, wherein the record carrier comprises a support layer and a photoconductive layer thereon, and the opposed surfaces of the photoconductive layer form image-receiving planes respectively for texts emanating from the two text sources, said support layer being transparent to the light incident directly thereon, and the image fields of the two text sources are constrained to expose complementary areas of the photoconductive layer.

8. An assembly for labelling merchandise packs, comprising means for advancing merchandise packs through a weighing station and a labelling station, and labelling apparatus for presenting at the labelling station a label marked with at least a first text in accordance with a weight output signal from the weighing station; said labelling apparatus comprising a label dispenser arranged to feed a continuous carrier on which labels are mounted through a label-processing station, the label processing station comprising recording apparatus in accordance with Claim 1 connected to receive said weight output signal to record at least characters dependent on the weight output signal on the labels as the record carrier.

9. An assembly according to Claim 8, in which each said label incorporates a photoconductive surface, said first and second text sources comprise first and second electro-optical devices arranged to present the required text scripts, the first electrooptical device being connected to receive the weight output signal via first data conversion means, the second electro-optical device being connected to an operatorcontrolled input via second data conversion means, and the recording apparatus further including an electrostatic charging device located prior to said label-processing station for photosensitizing the labels, and means

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. posed on the side of the paper strip 28' facing the printer 22'. When the hammer 58 presses against the paper, the character 62 of the drum 56 facing at that moment the inked ribbon 55 will appear on the side of the paper facing the ribbon. On the other hand, when the hammer 59 pertaining to the printer 23' situated at the rear is actuated, the profile of the character 63 on the drum 57 is pressed through the paper from the rear and is correspondingly inked on the front by the inked ribbon 55. The two printers 22', 23' may considerably overlap in height with respect to the paper strip 28', so that the print positions determined by the hammers 58, 59 can lie one close to the other and can therefore be used to imprint a joint label. After having been imprinted, the paper strip 28' is delivered in the direction of the arrow 60. Though the printers are disposed on both sides, the type face appears on a common display surface, marked 61 in Fig. 6.If the paper strip is provided with an adhesive layer at the rear which can be covered with a foil while the strip passes through the printer 22', 23', the finished label can be easily attached to the corresponding packing of the article. As a matter of course, the invention permits information converters of different prior art design to be used for applying the data to a record carrier. The invention makes it always possible to obtain a high information density of jointly recorded symbols. WHAT WE CLAIM IS:

1. Apparatus for recording texts on a record carrier, comprising means for moving a record carrier through a recording zone at which there are located first and second text sources, said text sources being disposed at opposite sides of the carrier and being provided with character script for recording characters on the record carrier, one of the text sources being adapted to record characters on the record carrier from the front thereof and the other text source being adapted to record characters on the record carrier from the rear thereof so as to be readable from the front.

2. Apparatus according to Claim 1, wherein each text source is in the form of a rotatable drum carrying characters in raised formation thereon, a hammer for co-operation with a selected character, and an inked ribbon intermediate the hammer and the drum.

3. Apparatus according to Claim 1, wherein each text source produces an optical image text to be printed on the record carrier, and the apparatus incorporates an electro-static charging device having opposed electrodes between which the record carrier, which has a photoconductive surface, passes prior to entering the recording zone.

4. Apparatus according to Claim 3, wherein each text source comprises a liquidcrystal cell the optical output of which is controllable by an electrical input signal.

5. Apparatus according to Claim 3.

wherein one text source comprises a liquidcrystal cell the optical output of which is controllable by an electrical input signal, and the other text source comprises a transparency exchangeably mounted in a holder.

6. Apparatus according to any preceding Claim, wherein one text source is automatically controllable to provide a variable text and the other text source provides a nonvariable text.

7. Apparatus - according to Claim 3, wherein the record carrier comprises a support layer and a photoconductive layer thereon, and the opposed surfaces of the photoconductive layer form image-receiving planes respectively for texts emanating from the two text sources, said support layer being transparent to the light incident directly thereon, and the image fields of the two text sources are constrained to expose complementary areas of the photoconductive layer.

8. An assembly for labelling merchandise packs, comprising means for advancing merchandise packs through a weighing station and a labelling station, and labelling apparatus for presenting at the labelling station a label marked with at least a first text in accordance with a weight output signal from the weighing station; said labelling apparatus comprising a label dispenser arranged to feed a continuous carrier on which labels are mounted through a label-processing station, the label processing station comprising recording apparatus in accordance with Claim 1 connected to receive said weight output signal to record at least characters dependent on the weight output signal on the labels as the record carrier.

9. An assembly according to Claim 8, in which each said label incorporates a photoconductive surface, said first and second text sources comprise first and second electro-optical devices arranged to present the required text scripts, the first electrooptical device being connected to receive the weight output signal via first data conversion means, the second electro-optical device being connected to an operatorcontrolled input via second data conversion means, and the recording apparatus further including an electrostatic charging device located prior to said label-processing station for photosensitizing the labels, and means

located downstream of the electro-optical devices for fixing the charge on the label surface.

10. Apparatus for recording texts according to Claim 1, and substantially as hereinbefore described with reference to any one of the embodiments illustrated in the accompanying drawings.