PRINTING BLOCK

Abstract: A method for application of at least one image (5) onto a printing block (1, 22), which image is then transferred to a pad, whereupon the image (5) is pad printed on a component, preferably on the inner sides of a mobile telephone cover, at which the printing block (1, 22) comprises sides (8, 26), which can be angled in relation to each other, said image being applied onto said sides.

Description: PRINTING BLOCK Technical Ωeld of the invention The present invention relates to a method for a printing block and a printing block for pad printing of an electrically conductive image on a component, preferably a mobile telephone cover. Background of the invention It is possible, with constructions of the kind in question, available on the market, by means of a method called pad printing, to transfer an image from a flat printing block to a component, which has a surface which is substantially flat or only just a little curved, as for example a ball, the front of a mobile telephone, etc. If one wants to pad print on more complicated surfaces, which are provided with corners, and which, in addition presents surfaces, which are both curved and/or angled, such as for example the inner side of a cover for a mobile telephone, the pad printing technique of today will not suffice, because the pad cannot be provided with colour on its sides, but only on its bottom. The pad collects colour from the printing block in a direction from a straight above when encountering this. Consequently, today's printing blocks can pad print only on components that have only one boundary surface. Additionally, it becomes very difficult to reach with the pad, to pad print in depressions and at elevations in the component, because the printing block does not reach to transfer enough colour to these convex and/or concave parts of the component. With other known methods than the one described above, such as vacuum-vapourizing and spray-painting, it is possible to provide these units with an electrically conductive layer also on hard-to-reach places. However, they become more expensive to apply than pad printing, since, among other things, one gets rid of costs of removing undesired colour from places where it should not be, at e.g. holes, fittings and front sides. Also, no wastage of colour arises, since only the picture that is needed is printed. Moreover, the machines that are used for this method are cheaper. Also this method is easy to automate, for which reason also the handling cost becomes low. It is therefore very interesting to solve the problems that are present in the pad printing method, so that pad printing in corners and on its surrounding sides and on curved and angled surfaces becomes possible. It should be understood that Ericsson has a number of applications in process which precisely refer to pad printing of electrically conductive layers on mobile telephone covers. Summary of the invention Thus, an object of the present invention is to eliminate the disadvantages that are present with the above mentioned constructions by adapting the shape of the printing block according to the shape of the pad, which in turn is adapted to the shape of the component, which can be equipped with concave, convex and angled surfaces, so that at least one connecting side of the component can be printed at the same time. By providing ducts to the printing block, which ducts remove gatherings of air at the corners of the component and other cavities, the printing block can no longer be prevented from transferring colour to the pad in said hard-to-reach places. Thanks to the invention one has now achieved an adaptation of the appearance and shape of the printing block, to the component which is to be pad printed, by dividing the printing block into smaller parts which are formed in different ways. They can, for example, be flat, concave, convex or combinations of these shapes. These parts are, according to the invention, solidly or movably applied to each other to form a complete printing block. This can, according to the invention, in at least one of its parts, present at least one corner or at least one radius in its surface, which is formed by at least two sides angled to each other. When applying colour to the printing block, a scraper is used which is led across this, so that a predetermined amount of colour is put in an at least one depression present on the printing block, so that an image is created. This can be done in different ways. One such way is to lay the movable printing block with all its parts flat when the colour is applied. Another way is to curve and form the printing block according to the shape of the pad when the colour is applied, which colour is then to be transferred to the pad. This moves mainly from above and downwards and encounters the printing block, which then can be formed according to the shape of the pad by means of at least one arm connected to the parts of the printing block, which arm is capable of setting at least one printing block part to a predetermined position. Hence, each part of the pad which is to be provided with colour, can be reached by the formed printing block, so that the colour can be transferred. Another way of transferring colour to the pad is carried out so that the pad, which is soft, when pressed down is flattened against the bottom of the formed printing block so that a counter-pressure is formed in this, which in turn causes a deformation of the pad, whereby this then expands in another direction, whereby it touches at least one angled and/or curved side of the printing block, which side is covered with colour, whereby this is transferred to the pad. Via at least one duct and/or at least one hole, leading from a corner, present in connection with the printing block, a gathering of air formed at this corner is carried off, which gathering of air is created when the pad is being pressed down against the printing block. This prevents the colour from lying in corners and other hard-to-reach places of the printing block. In a preferred embodiment of the invention, the colour is first collected from a printing block, which has curved, but not movable sides, which colour has been applied to the printing block and scraped out, so that a predetermined image has been achieved. For the image to stick to the sides of the pad, the printing block has a form which is adapted to the shape of the pad. The scraper, which flattens the colour on the printing block, has the ability to follow the irregular surface of the printing block since its mounting is flexible. This can be secured to an axle, so that it can pendulate with a predetermined movement or it can be movably secured in a track which follows the formation of the printing block. Alternatively the pad can perform a rotary movement over the printing block, at which firstly the side is laid against the printing block so that it is provided with colour. Thereafter the rotary movement of the pad continues with continuous contact with the printing block, so that the application angle towards this is changed continuously, at which the rest of the image sticks to the pad. One can also consider, according to the invention, that the printing block is equipped with movable boundary surfaces, which can assume a position which makes the whole printing block flat when the colour is applied, at which the scraper then moves across its entire surface, to press colour into the stamping of the printing block. Before the pad collects the colour from the printing block, this changes its shape so that it is adapted to the shape of the pad, by means of actuation of its surfaces so that they bend due to the printing block being formed in a flexible material and/or be provided with a hinge function, which is connected to other parts present in the printing block, whereby the colour can be transferred to the different boundary surfaces of the pad. When pad printing a component which is formed as the inner side of the cover of a mobile telephone, the printing block according to the invention in the preferred embodiment is built up mainly as a box, provided with a mainly flat bottom. To this, for example four mainly vertical sides connect. When the scraper scrapes the colour in the etched depressions of the printing block, the sides and the bottom of the printing block lie flat. Thereafter, the sides are put in a mainly vertical position. The pad now collects the colour from the printing block in three steps. Firstly, the image is delivered from the bottom of the printing block by means of the pressure of the pad. In step two, a continued compression of the pad deforms a bottom surface present on the pad, at which this deformation propagates through the pad, so that at least one existing side thereof comes into contact with the mainly vertical sides of the printing block, at which these also deliver colour to the pad. According to the invention, in step three, the corners of the pad will be pressed into the corners of the printing block. In these corners, air is easily gathered, which may need to be ventilated via air ducts and/or holes in the printing block in connection with the corners, to get rid of the gatherings of air, which prevent the colour from sticking to the printing block. According to the invention, one can also consider a pad consisting of a rotary wheel, which collects its picture via a rotating wheel-shaped printing block, moving with the same speed. The method described above to transfer colour from the printing block to the pad in three steps, can also be used with the rotating printing block, which is then provided with a bottom and sides that are shaped as a U in section, which bottom compresses the rotating pad, so that its sides are capable of pressing against the sides of the printing block. Through the method with a form-adapted printing block, which is provided with flat, flexible and angled surfaces, it becomes possible to transfer images from this to a pad, despite this having a complicated shape, such as comers, curved sides and angled sides. The greatest advantages of the invention are that one can pad print an image much faster with a fewer amount of pad prints on complicated surfaces. This applies especially to rotating printing blocks and rotating pads. Additionally, by means of holes and ducts, one gets rid of the problem of the gathering of air which remains in the comers during pad printing. Brief description of the drawings Below the invention is described closer by means of a few preferred embodiments with reference to the accompanying drawings, in which: Fig. 1 shows a schematic perspective view of a flat printing block with an applied image according to the present invention, which is built up of partial printing blocks, Fig. 2 shows a schematic perspective view of a printing block formed according to a pad, before the pad collects the image, Fig. 3 shows a sectional view of a printing block in a resilient material, which is formed according to the shape of the pad, before the pad collects the image, Fig. 4 shows a view of a rotating wheel with a plurality of printing blocks and a section through one of the printing blocks, Fig. 5 shows a schematic perspective view of a section through a printing block, which mainly resembles a box provided with air- venting holes. Detailed description of an embodiment of the invention As can be seen from the embodiment shown in Fig. 1 , the device according to the invention comprises a printing block 1, which is in step 1 of a pad printing method, which printing block presents a plurality of partial printing blocks 2, which are mainly flat, which are movably connected to each other by means of a hinge function 3, which makes it possible to rotate the partial printing blocks upwards around the hinge function 3 in a rotational direction 4. A slit 6 is made in the printing block 1, to make it possible to fold the partial printing blocks 2 upwards. Colour 5 is applied with a scraper so that the image 5 has been created in a depression present in the printing block 1, at which for example certain recesses 7 are positioned at chosen places. In this case, the image 5 is an electrically conductive layer, which is to be collected by a pad and then pad printed onto the inner side of a mobile telephone cover. The recesses 7 consist of holes in the layer to give room for buttons, speaker, antenna, contacts etc. present in a mobile telephone. As can be seen from the embodiment shown in Fig. 2, the printing block 1 according to Fig. 1 is in stage 2 of the pad printing method, at which the partial printing blocks 2 have been folded upwards around the hinge function 3 by a mechanism, which mechanically via devices 10 preferably connected to at least one partial printing block 2, is capable of actuating these, so that they assume a mainly upright position, at which the printing block 1 mainly resembles a box. This is now adapted to the shape of the inner side of the mobile telephone cover. Naturally, one can consider the partial printing block 2 also having a somewhat angled position, so that it does not stand entirely upright. In this position the pad, which mainly is formed like the inner side of the mobile telephone cover, can collect the image 5 from the printing block 1, at which the sides 8 and the bottom 9 of the image are collected, to then be pad printed onto the inner side of the mobile telephone cover. As can be seen from the embodiment shown in Fig. 3 and which corresponds to step 2 according to Fig. 2 in the pad printing method, the printing block 1 is built up of a resilient material, such as metal sheet, which by means of the devices 10 has assumed a position, so that the printing block 1 in at least one place presents a curved side 30 or an angled side 8 according to Fig. 2. Previously the colour has been applied in a flat position according to step 1 above. If the printing block is permanently formed, so that it is not movable, the image 5 cannot be applied according to what is described in Fig. 1. Instead, the scraper 11 must be able to move so that it is in contact with the printing block all the time according to a predetermined pattern of movement, so that the colour has the possibility of being scraped out over the entire printing block, even if it presents a plurality of angled and/or curved sides. A distance, which consists of a stretch 12 from the surface of the printing block 1 to a fastening point 18 on an arm 13 existing on the scraper 11, must therefore be adapted together with an application angle 14, so that at least one leg 16 on the scraper, during the movement of the scraper 11, is always capable of pressing the colour against a hollow 17 of the printing block, so that it, during its entire pattern of movement, abuts against the printing block. To achieve this, the arm 13 is mov-ably secured in a guide rail 19, which in turn is secured somewhere on a pad printing machine used for the pad printing method. In the guide rail 19 at least one guide field 20 is applied in the form of at least of one track formation or similar, the effect of which is that the scraper can perform a predetermined movement. Also, the arm 13 can be provided with one additional fastening point 21 , which is also movably secured to the guide rail 19, so that the arm 13, when moving along the guide rail 19, can change its application angle 14. Also according to the invention, the printing block 1 can be provided with partial printing blocks 26 on the sides, which are movably or permanently applied on the printing block 1, according to what is mentioned above in Figs. 1 and 2. The scraper 11 can then be supplemented so that it also scrapes colour into depressions 17, which are present in the partial printing blocks 26, to create an image 5 in these places as well. In this way it becomes possible to provide a pad with colour on more than one side. As can be seen from the embodiment shown in Fig. 4, a rotating wheel 27 is shown, which presents a plurality of printing blocks 22 applied in the area at the periphery of the wheel 27, which wheel 27 is applied onto an axle 23, so that it is able to rotate in a direction 24. During the rotation, a scraper 11 is to apply colour so that an image 5 is created on the printing blocks 22 in a continuous process, i.e. each printing block, one after the other, is provided with the image 5 in the manner described according to Fig. 3, with the exception that, since the wheel 27 is rotating, the scraper 11 does not need to move according to a guide field 20. However, the application angle 14 and/or the distance 12 need to be able to vary during the rotation. As can be seen from the printing block shown in Fig. 5, it is equipped with four sides 8, which are in a mainly upright position, so that comers are formed in the printing block. A pad is to collect an image 5 applied to the printing block 1. When the pad is pressed down into the printing block 1, an air volume present in the printing block is compressed, at which this can escape through holes 29 present in the comers, at which the pad will be able to collect the entire image 5, also in the comers of the printing block 1. In the following claims, the expression "complementary fit" will be used to describe the shape of the printing block relative to the pad. Naturally, this shape refers to the inverted shape of the pad. Thus, if the pad has a brick-like shape, the printing block has a box-like shape, in which the brick (the pad) can be immersed. Thus, the inside of the box (the printing block) has a complementary shape in relation to the brick (the pad). What has been mentioned above should only be regarded as an advantageous embodiment of the invention, and the scope of the invention is limited only by what is mentioned in the following claims.

Claims: Claims 1. A method for application of at least one image (5) onto a printing block ( 1 ,22), which image is then transferred to a pad, whereupon the image (5) is pad printed on a component, preferably on the inner side of a mobile telephone cover, characterized in that the printing block (1,22) comprises sides (2,8,26), which can be angled in relation to each other, said image being applied onto said sides. 2. A method according to claim 1, characterized in that the printing block (1) is flat when the image (5) is being applied. 3. A method according to claim 2, characterized in that after application of said image (5), the shape of the printing block is changed so that it assumes a complementary fit in relation to the shape of the pad, which pad then collects said image (5). 4. A method according to claim 3, characterized in that the printing block (1) comprises partial printing blocks (2,8,26), which are folded upwards around a hinge function (3), to achieve said complementary fit corresponding to said pad. 5. A method according to claim 1, characterized in that the printing block (1,22) is perma-nent without movable partial printing blocks (2,8,26), at which the application of the image (5) is done by means of at least one scraper (11), which is movably applied at least at one fastening point (18,21). 6. A method according to claim 5, characterized in that the scraper (11) is capable of applying said image (5) while moving along at least one guide rail (19). 7. A method according to claim 6, characterized in that the guide rail (19) is provided with at least one guide field (20), which, together with at least one fastening point (18,21), is capable to adapt an application angle (14), so that the scraper (11) during its continuous movement is in contact with the printing block (1,22). 8. A method according to any of the previous claims, characterized in that said image is built up of an electrically conductive colour. 9. A printing block, characterized in that it is formable to a shape corresponding to a com-plementary fit for a pad, which is intended to collect an image applied onto the printing block. 10. A printing block according to claim 9, characterized in that it comprises partial printing blocks (2,8,26), which are movably applied to each other by means of at least one hinge function (3). 11. A printing block according to claim 9 or 10, characterized in that it is made of a resilient material so that it is formable to said complementary fit for said pad. 12. A printing block according to any of the claims 9-11, characterized in that it at least comprises at least one air duct (29). 13. A printing block according to any of the claims 9-12, characterized in that it is applied to a wheel (27) rotating around an axle (23) in a predetermined direction (24). 14. A printing block according to any of the claims 9-13, characterized in that said image (5) is built up of an electrically conductive colour. 15. A printing block according to any of the claims 11-14, characterized in that it has a shape corresponding to the inner side of a mobile telephone cover. 16. A wheel, characterized in that it comprises a plurality of printing blocks (1,22), which are arranged at the periphery of the wheel, said wheel being arranged to rotate around an axle (23). 17. A wheel according to claim 16, characterized in that said printing blocks are arranged as recesses in said wheel, which recesses have a shape which substantially corresponds to a complementary fit in relation to the shape of the pad, which collects an image applied onto the printing block.

Inventors: ERIKSSON LARS, HOLMBERG PER, ERIKSSON, LARS, HOLMBERG, PER
Applicants: ERICSSON TELEFON AB L M, TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Application year: 2000
Main classification: B41F7
IPC codes: B41F17, B41M1, B41N1, H04M1