Abstract:
The side wall ( 5 ) for an ink fountain of a printing machine has two plates ( 11, 14 ) fixed some distance apart and an intermediate plate ( 13 ) having a front edge ( 13   a ) in the shape of an arc of a circle. This intermediate plate ( 3 ) is mounted between the plates in such a way that it can be shifted and tilted. The front edge of this plate contacts the circumference of an ink fountain roller ( 6 ) via springs ( 18, 19 ) acting on the intermediate plate. The wall has a slideway ( 10 ) in which the plates ( 11, 14, 13 ) are mounted. The slideway has a reinforced region ( 12 ) on one of its sides which is proximate the ink fountain roller ( 6 ). The side wall ( 5 ) thus more effectively seals an ink fountain against leakage. The blade at the bottom of the ink fountain is split into several adjacent sectors ( 111 ) that can be shifted so as to vary the distance between the edge ( 112 ) of the blade and the circumference of the ink fountain roller ( 6 ). The sectors ( 111 ) can be shifted in the plane of the blade, parallel to each other.

Description:
This is a continuation-in-part application of U.S. Ser. No. 09/483,815 filed Jan. 15, 2000 by the same inventor and entitled SIDE WALL FOR AN INK FOUNTAIN OF A PRINTING MACHINE, the contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to an ink fountain for a printing machine, said ink fountain comprising an ink fountain roller, a bottom in the form of a blade, the edge of which is close to the ink fountain roller circumference, and two side walls in contact with the bottom of the ink fountain and sealing the sides of the ink fountain. The blade&#39;s edge is intended to maintain a determined thickness of ink on an ink fountain roller, said blade being split into several adjacent sectors that can be shifted so as to vary the distance between the edge of the blade and the circumference of the ink fountain roller. 
     These blades and ink fountains are used mainly in intaglio printing machines in which the amount of ink applied to the ink fountain roller is great, so as to adequately ink the intaglio cuts in the printing plates. 
     Ink fountain blades and ink fountains of this type are known in the state of the art. For example, patent DD 110 632, the content of which is incorporated by reference, discloses an ink fountain, the bottom of which has a blade which is close to the circumference of the ink fountain roller. In order to vary the distance between the edge of the blade and the roller, that is to say the thickness of ink applied to the roller, the blade is deformed elastically by screws which press against the blade, on the other side thereof with respect to the ink fountain roller. 
     The major disadvantage of this system lies in the fact that the deformation of the blade does not allow a constant thickness of ink to be applied. This is because the profile of the deformed blade has, roughly speaking, a rounded shape because the screws press at a point location on the blade, which means that the metering of the ink is thus inaccurate. 
     Another system is described in patent application EP 0 600 435, the content of which is incorporated by reference. In this system, the ink fountain blade is formed of several adjacent bladelets which can be elastically deformed in order to modify the thickness of ink applied to the ink fountain roller. To obtain this deformation, use is here too made of a lever on the other side of the bladelets with respect to the ink fountain roller in order to move them closer to this roller and thus alter the distance between the edge of each bladelet and the circumference of the ink fountain roller and thus the thickness of ink applied. 
     This system has several drawbacks, particularly the fact that the deformation of the bladelets occurs toward the ink fountain roller. Thus, in the event of an error of manipulation, there is the risk that the blade will come into contact with the roller and damage it. The deformation of the blades also leads to fatigue in the material and this may create problems of premature wear. 
     SUMMARY OF THE INVENTION 
     The purpose of the invention is to improve the known systems. 
     More specifically, the object of the present invention is to provide an ink fountain in which the sealing of the side walls is markedly improved, and to do so in a simple manner and at fairly low cost. Another object of the present invention is to provide a system which can be retrofitted to existing machines, that is to say a system which can be mounted in ink fountains which are already in service without major modification thereto. Another object is to provide a segmented fountain blade which has a fine adjustment to allow a constant thickness of ink to be applied to the ink fountain roller, precisely, repeatably and without risk of damaging the roller. 
     The invention is characterized by the fact that the sectors forming the blade at the bottom of the ink fountain can be moved in the plane of the blade parallel to one another. 
     The advantages afforded by the use of a blade split into sectors according to the invention are many. Mention may, in particular, be made of the fact that the movement of the sectors is linear, which means that it is easier to control and to measure than the movement of the bladelets described in patent application EP 0 600 435. Specifically, any arbitrary point on a blade sector according to the invention has the same movement, whereas in the case of the bladelets known from the prior art, a precise measurement of the movement could be made only on the actual edge of each bladelet. 
     The invention will be better understood from the description of one embodiment thereof and from the figures pertaining thereto. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 diagramatically shows an inking device comprising two ink fountains; 
     FIG. 2 shows a view in part section of a side wall of an ink fountain, from the inside of the ink fountain, and 
     FIG. 3 shows a view from above in section on the axis III—III of the side wall of said FIG.  2 . 
     FIG. 4 shows a detailed view in part section of the bottom of an ink fountain, 
     FIG. 5 shows a view from above of part of the ink fountain, and 
     FIG. 6 depicts a dividing wall suitable for mounting in an ink fountain including a blade according to the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 depicts an inking device with two superposed ink fountains, of the type used in intaglio printing machines. This device is made up mainly of a mobile linking carriage  1 , comprising two superposed frames  2 , each frame  2  being equipped with an ink fountain  3  formed of a bottom  4  and of two side walls  5  collaborating with the ink fountain roller  6 . The bottom  4  is formed of a blade, the front edge of which is close to the ink fountain roller  6 . To illustrate one application of this ink fountain  3 , FIG. 1 also diagrammatically depicts inking rollers  7  which, for example, ink impression plates (not depicted) mounted in a plate cylinder  8 . 
     FIG. 2 is a detailed depiction of a side wall  5  seen from inside the ink fountain  3 . 
     This side wall  5  comprises a slideway  10  which is mounted on the bottom of the ink fountain  3 , for example by a screw-fastening using screws  29 . The front end of the slideway  10  which is on the inside of the ink fountain  3  is in contact with the ink fountain roller  6 . The slideway  10  at this point has a reinforcement  12 , such as a small plate of hard material, for example metal or ceramic, which completely seals the joint between this wedge shape and the roller  6 . 
     Specifically, as the front edge of the slideway is in contact with the periphery of the ink fountain roller  6 , the sharp edge of the slide way is blunted because of the abrasive properties of the ink, which means that ink can run near the seal with the side wall  5 . Thus, to improve the sealing of this seal, a housing is milled on the inside end of the slideway, in which housing the small plate of hard material  12  is fixed, and wear is markedly reduced. 
     The side wall  5  itself comprises a first plate  11  which slides without play in said slideway  10 , from the opposite end to the ink fountain roller  6 . Mounted next on this first plate is an intermediate plate  13 , the front edge  13   a  of which is in the shape of an arc of a circle and which plate is intended to come into contact with the circumference of the ink fountain roller  6 . This intermediate plate is generally made of plastic, for example “NYLATRON”, and provides for the sealing of the side wall  5  along the circumference of the ink fountain roller  6 . 
     This intermediate plate  13  can move longitudinally, in the direction perpendicular to the axis of rotation of the ink fountain roller  6  or in terms of rotation about an axis parallel to the axis of rotation of the ink fountain roller  6  and is kept pressed against the ink fountain roller  6  by means of the two springs  18  and  19 , placed in corresponding cavities  20 ,  21  in the first plate  11 . The axis of rotation of the intermediate plate  13  is close to or even coincident with the axis of a screw  24 , depending on the longitudinal position of the intermediate plate  13 . Furthermore, the two springs  18  and  19  are located one on each side of this axis of rotation of the intermediate plate  13 . As a preference, the two springs  18 ,  19  may be preloaded by screws  22 ,  23 . To protect the rear portion  13   b  of the intermediate plate  13  on which the two springs  18 ,  19  act, a small protective plate  15  is placed on said rear portion  13   b , and held in place, for example using screws  16  and  17 . 
     A second plate  14  is fixed to the first plate  11  by the screws  24 ,  26  and serves both to close the device and to protect the intermediate plate  13  from the ink, particularly as the latter is drying. Thus, the intermediate plate still slides correctly even if the ink has thickened or dried, and the ink fountain remains sealed. 
     To hold the side wall  5  in place in the slideway  10 , use is made of a screw  25 , the end of which may be knurled to make it easier to tighten and slacken by hand. 
     To ensure a perfect seal, that is to say the absence of play, between the small plate made of hard material  12  and the intermediate plate  13 , it is necessary to provide a special system for adjusting the position of the intermediate plate  13  sideways with respect to the slideway  10 . One embodiment of this system is depicted in detail in FIG.  3  and comprises two inclined planes which collaborate in the manner of a wedge. A first inclined plane  30  is formed on the inside of the first plate  11  and a second inclined plane is formed on an intermediate part  31  which moves with respect to the first plate  11  by sliding along the first inclined plane  30 , thus allowing the intermediate plate  13  to be adjusted sideways in the direction of the small plate of hard material  12  and allowing play to be eliminated. The wedge system is locked in place by the screws  27  which pass through oblong holes  28  in the intermediate part  31  and screw into the first plate  11  (see FIG.  2 ). 
     The wedge system can be adjusted by hand, by adjusting the position of the intermediate plate  13  toward the piece of hard material  12 , little by little, or alternatively, use may be made of a system involving a cam  32  mounted on an axle fixed to the first plate  11  and actuated by the screw  33 , the cam  32  acting on the intermediate part  31  so as to move it longitudinally in a direction perpendicular to the axis of the ink fountain roller  6  and thus, via the wedge system, move the intermediate plate  13  toward the piece of hard material  12 . 
     To hold the intermediate plate  13  between the plates  11  and  14 , the intermediate plate  13  is pierced with a hole through which a bushing  35  passes (see FIG.  3 ). This bushing  35  is itself held in position by screws  24  and  33  which pass through the plates  14  and  11  respectively. 
     The embodiment described is described by way of example and the side wall on the other side of the ink fountain  3  may be constructed in the same way as the one described hereinabove but as a symmetric inversion, so that the piece of hard material  12  and the plate  15  are on the inside of the ink fountain  3 . 
     Furthermore, the invention is not restricted to the embodiment described and variations may be made within the scope of the claimed protection. For example, the intermediate plate may be adjusted sideways by other means equivalent to the wedge system described. 
     The materials used, particularly those of the small plate  12  and intermediate plate  13  which forms the seal may be varied. 
     The bottom  104  of the ink fountain is described in detail with reference to FIGS. 4 and 5. This bottom  4  is mounted on a transverse spindle  110  parallel to the axis of the ink fountain roller  6  and pivots about this spindle  110  toward the ink fountain roller  6  as the ink fountain is brought into operation. Blade segments  111  are mounted on the bottom  104 . These segments  111  are connected to the bottom  104  by transverse slideways  113 ,  114  parallel to the spindle  110  supporting the bottom  104  and which are themselves fixed to said bottom  104  by means of screws  115  and  116 . These transverse slideways  113 ,  114  have the overall shape of a T, the top of which is held in a corresponding slot  132 ,  133  cut in the segments  111 . All the segments  111  may thus be mounted on the bottom  104  of the ink fountain by introducing them sideways into the transverse slideways  113  and  114  and, once they are all in place, they can then be moved at right angles to the spindle  110  of the ink fountain by virtue of the clearance that there is between the T-shaped top of the slideways  113 ,  114  and the corresponding slot  132 ,  133  of the segments. 
     At right angles to the slideways  113 ,  114 , each segment  111  has housings  119 ,  120 , in each of which a return spring  117 ,  118  is placed. These springs  117 ,  118 , which work in compression, serve to keep the segment  111  in the position in which the edge of the segments  111  is closest to the ink fountain roller  6 . This position may thus be defined as being a reference position, and the movement of the segments  111  in order to alter the thickness of ink applied to the roller  6  is performed by moving the sector  111  away from the roller  6 . 
     The edge of the sector  111  is reinforced  112 , for example by a wafer of hard material such as metal or ceramic which allows the life of each sector to be lengthened considerably. This is because the inks used have abrasive properties which wear the edge of the blade away. However, in order to maintain application of a precise thickness of ink to the roller  6 , it is necessary for the blade to be sharp-edged. The use of reinforced sectors according to the present invention thus makes it possible, on the one hand, to reduce the wear on the edge and, on the other hand, for just one sector to be changed in the event of premature wear, rather than the entire blade, thus resulting in an appreciable saving. 
     There is a specific system provided for shifting each sector  111 . This system comprises a cam  123  which, in FIG. 4, is associated with a motor  121 . The cam  123  is placed in a corresponding slot  124  in the sector  111  and mounted on the spindle  122  of the motor  121 . The motor  121  itself is mounted in the bottom of the ink fountain  104  and is fixed in by screws  125  and  126 . The use of a motor as depicted in FIG. 4 in particular allows the movement of the sectors  111  to be controlled remotely. Thus, using an appropriate device, the position of each sector can be adjusted constantly to suit the quality of print produced, by combining the system described with computerized control means, for example. Of course, it is not necessary for the movement of the cams  123  to be motorized and it is possible to replace the motors  121  with a manual control acting on each cam  123 . 
     FIG. 5 diagrammatically depicts six adjacent sectors  111 ,  111 ′ of an ink fountain. For a better understanding of the invention, the middle sector, referenced with the number  111 ′, is depicted with an exaggerated offset. This offset thus allows the application over a determined width of a constant thickness of ink which is different than the thickness of ink applied by the adjacent sectors  111 . According to the size of the pattern which than one sector  111  at a time, if the width of the pattern exceeds the width of one sector  111 . 
     Advantageously, a blade with sectors  111  according to the invention can be used in an ink fountain comprising ink dividers. Such dividers are used to separate the colors when the ink fountain is used for multicolor printing. U.S. Pat. No. 4,991,504, the content of which is incorporated by reference, for example, describes an ink fountain including at least one such divider allowing inking with at least two different colors. 
     By attaching a divider directly to a sector  111 , there is obtained a modular system in which any arbitrary sector as described hereinabove can be fitted with a divider so that the assembly allows numerous combinations. 
     FIG. 6 diagrammatically depicts a divider  127  mounted directly on a sector  111  according to the invention. The elements which are common to FIGS. 4 and 6 are identified with the same references. The divider  127 , known per se for example from U.S. Pat. No. 4,991,504, comprises an intermediate plate  128  made of plastic, for example “NYLATRON” which is kept in contact with the periphery of the ink fountain roller  6  by press means (not depicted) such as springs, so that the contact remains leaktight. 
     If the divider  127  is not as wide as the segment  111  on which it is mounted, then the edge of the segment  111  on the same side as the ink fountain roller  6  needs to be reinforced, for example using a wafer of hard material  131  similar to the wafers  112  depicted in FIGS. 4 and 5. A wafer  131  of this kind will in fact be placed on each side of the intermediate plate  128 . It will thus be possible to shift the segment so as to precisely adjust the thickness of ink applied in the vicinity of the intermediate plate  128  while at the same time maintaining sealed contact of this plate against the ink fountain roller  6 , by virtue of the press means. 
     The embodiments of the invention are described by way of example and variations are possible within the scope of the claimed protection. For example, the number of slideways  113 ,  114  may be increased. It is also possible to envisage return means other than the springs  117 ,  118 . Likewise, use may be made of another system equivalent to the system of cams used for moving the segments  111 .