Patent Abstract:
A rotary screen printing press, which includes a rotary screen cylinder for coating ink on a sheet transported by transport means, and a plate or forme replacing work space whose upper side is closed, with respect to which a transport direction of the sheet is restrained by other device and a liquid coating unit including the rotary screen cylinder, which is open in at least one of directions orthogonal to the transport direction of the sheet, and where an operator performs work of replacing a screen printing forme, comprises a plate or forme rest provided below the rotary screen cylinder and supported to be movable to a first position within the liquid coating unit and a second position within the forme replacing work space.

Full Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to a liquid coating machine of a rotary screen printing press or the like. 
         [0003]    2. Description of the Related Art 
         [0004]    In screen printing by a rotary screen printing press, ink is placed in a screen printing forme, and the screen printing forme is pressed against paper by a squeegee or a doctor roller to transfer the ink to a printing surface of the paper through the openings of the screen printing forme. The screen printing forme needs to be replaced each time a different printing product is to be printed. 
         [0005]    The work of replacing the screen printing forme will be described, for example, in connection with an intaglio and rotary screen printing press as shown in  FIG. 6 . 
         [0006]    In this printing press (liquid coating machine), sheets of paper (sheets, for short) W are fed one by one from a feeder  10  onto a feedboard  11 . Then, the sheet W is passed from a swing arm shaft pregripper  12  on to a transfer cylinder  13 , and then gripped by grippers  14   a  of an impression cylinder  14  for the purpose of transport (transport means). On the other hand, conventional inks are supplied from within ink fountains  20  to chablon rollers  17  via ink fountain rollers  19  and intermediate rollers  18 , and supplied to an ink collecting cylinder  16  (other device). Then, the inks are collectively supplied to an intaglio plate of a plate cylinder  15 . Also, special ink is directly supplied, in a constant amount in a predetermined pattern, from within a rotary screen cylinder (stencil printing cylinder)  22  to the intaglio plate of the plate cylinder  15  via a rubber roller  21  (liquid coating unit). 
         [0007]    These inks have their surplus amounts removed by a wiping roller  23 , and are then transferred to the sheet W passed on to the impression cylinder  14  for the purpose of printing. The printed sheet W is transported and delivered by a delivery chain  26  via a delivery cylinder  25 . 
         [0008]    In such a rotary screen printing press, when the screen printing forme (stencil printing plate) of the rotary screen cylinder  22  is to be replaced, it has been common practice for two operators to hold opposite end portions of the screen printing forme in places near entrances  28  to the machine. This is because a forme or plate replacing work space S for replacing the screen printing forme of the rotary screen cylinder  22  has its upper side closed with a printing unit or a transport unit for the sheet W, and has its fore-and-aft direction restrained by other printing devices. Thus, the space S is only a narrow space defined by these printing devices. Moreover, the machine entrances  28  formed on both sides of a machine frame  27  are narrow. These situations make it difficult for one operator to do replacing work while holding the screen printing forme. 
         [0009]    Thus, the two operators have to do the work in a well-coordinated manner with an unnatural posture, thus posing the problems of decreasing the operators&#39; work efficiency and imposing a burden on the operators. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention has been proposed in light of the above-described problems. It is an object of the invention to provide a liquid coating machine by which only one operator is required to do the work of replacing a stencil printing plate with ease. 
         [0011]    An aspect of the present invention is a liquid coating machine including transport means for transporting a sheet, a stencil printing cylinder, provided below the transport means, for coating a liquid on the sheet transported by the transport means, and a plate replacing work space whose upper side is closed, with respect to which a transport direction of the sheet is restrained by other device and a liquid coating unit including the stencil printing cylinder, which is open in at least one of directions orthogonal to the transport direction of the sheet, and where an operator performs work of replacing a stencil printing plate, the liquid coating machine comprising a plate rest provided below the stencil printing cylinder and supported to be movable to a first position within the liquid coating unit and a second position within the plate replacing work space. 
         [0012]    The plate rest may be supported by a horizontal movement guide member to be movable to the first position and the second position. 
         [0013]    A rolling body may be provided on a surface on a side of the plate rest supporting the stencil printing plate, and the stencil printing plate may be supported via the rolling body. 
         [0014]    The liquid coating machine may further comprise a four-joint link for supporting the plate rest, and drive means for swinging the four-joint link, and the plate rest may be moved to the first position and the second position by the drive means via the four-joint link. 
         [0015]    An ink pan may be supported by the plate rest, and the stencil printing plate may be supported by the plate rest via the ink pan. 
         [0016]    A pair of plate bearers having inclined surfaces opposing each other may be integrally formed on an upper surface of the ink pan, and the stencil printing plate may be supported on the inclined surfaces of the plate bearers. 
         [0017]    A pair of plate bearers having a plurality of rolling bodies annexed thereto may be integrally formed on an upper surface of the ink pan, and the stencil printing plate may be supported by the rolling bodies of the plate bearers. 
         [0018]    The plate rest may be moved to reciprocate between the first position and the second position during the work of replacing the plate. 
         [0019]    According to the liquid coating machine concerned with the present invention, one operator is enough to perform the work of replacing the stencil printing plate easily, by using the plate rest, while avoiding the expansion of the plate replacing work space or the machine entrance of the frame. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
           [0021]      FIG. 1  is a schematic configurational sectional view of a rotary screen printing unit in a rotary screen printing press showing Embodiment 1 of the present invention; 
           [0022]      FIG. 2  is a schematic right side view of the rotary screen printing unit in  FIG. 1 ; 
           [0023]      FIG. 3  is a perspective view of a slide rail; 
           [0024]      FIG. 4  is an explanation drawing using a four-joint link and drive means (air cylinder) showing Embodiment 2 of the present invention; 
           [0025]      FIG. 5A  is an explanation drawing using rolling bodies (rollers) showing Embodiment 3 of the present invention; 
           [0026]      FIG. 5B  is an explanation drawing using the rolling bodies (rollers) showing the Embodiment 3 of the present invention; and 
           [0027]      FIG. 6  is a schematic configurational view of a conventional intaglio and rotary screen printing press. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    A liquid coating machine according to the present invention will be described in detail by embodiments with reference to the accompanying drawings. 
       Embodiment 1 
       [0029]      FIG. 1  is a schematic configurational sectional view of a rotary screen printing unit in a rotary screen printing press showing Embodiment 1 of the present invention.  FIG. 2  is a schematic right side view of the rotary screen printing unit in  FIG. 1 .  FIG. 3  is a perspective view of a slide rail. 
         [0030]    In a rotary screen printing unit in a rotary screen printing press (liquid coating machine), as shown in  FIG. 1 , a rotary screen cylinder (stencil printing cylinder)  32  is supported between right and left frames  31  erected on a bed  30  via eccentric bearings  33  to be capable of throw-on and throw-off with respect to a rubber roller, an impression cylinder, etc. (not shown). The right and left eccentric bearings  33  are supported by the right and left frames  31  to be pivotable and slidable in the lateral direction (axial direction). 
         [0031]    The rotary screen cylinder  32  comprises a cylindrical screen printing forme (stencil printing plate)  35  supported between right and left tubular end members  34 , and in small-diameter parts of the right and left tubular end members  34 , is also supported by the eccentric bearings  33  to be rotatable via bearings  36 . The screen printing forme  35  comprises a mesh-shaped body portion  35   a , and tubular mounting members  35   b  attached to the opposite ends of the body portion  35   a.    
         [0032]    A toothing  34   a  is engraved in the outer periphery of the small-diameter part of the right tubular end member  34 , and a gear  37  meshes with the toothing  34   a . Thus, the rotary screen cylinder  32  is rotationally driven, and can be circumferentially registered, by a motor (not shown) via the above-mentioned gear mechanism. 
         [0033]    In a slot formed in a flange portion  33   a  of each of the right and left eccentric bearings  33 , a head  38   a  of a bolt  38  is fitted to be rotatable and movable in the major-diameter direction of the slot, but immovable in the axial direction of the slot A threaded portion  38   b  of the bolt  38  is screwed into a threaded bore of the frame  31 . A gear  39   a  is secured to each of the heads  38   a  of the right and left bolts  38 , and a gear  39   b  secured onto an output shaft of a motor  40  meshes with each of the gears  39   a . The right and left motors  40  are mounted on support brackets  41  bound to the right and left frames  31 . 
         [0034]    Thus, the right and left eccentric bearings  33  are slid in the lateral direction (axial direction) by the motor  40  via the aforementioned gear mechanism and feed screw mechanism to permit the tension adjustment of the screen printing forme  35  and the movement of the bearings during removal of the screen printing forme  35 . 
         [0035]    A pipe-shaped support shaft  42  closed at a right end is inserted through the rotary screen cylinder  32 , and a rubber squeegee (not shown) is supported by the support shaft  42 . The leading end of this squeegee makes sliding contact with the inner peripheral surface of the screen printing forme  35  (body portion  35   a ) Thus, the ink (liquid) supplied through the interior of the support shaft  42  into the screen printing forme  35  is transferred onto a printing surface of the sheet via the openings of the body portion  35   a.    
         [0036]    In the present embodiment, as shown in  FIG. 2  as well, a quadrilateral frame-shaped forme or plate rest  50  having a withdrawing grip  51  annexed to each of right and left front parts thereof is disposed on the bed  30 , which is located below the rotary screen cylinder  32  in the assembled state, via slide rails  55  and angle members  56  to be described later. 
         [0037]    An ink pan  53 , which receives ink dripping from the screen printing forme  35  of the rotary screen cylinder  32  during printing and during stoppage of printing, is placed on the forme rest  50 . A pair of (i.e., front and rear) forme or plate bearers  52  having inclined surfaces  52   a  opposing each other are formed integrally with the ink pan  53 . A pull-out grip  54  is annexed to each of right and left parts of the ink pan  53  (the pull-out grip  54  may be provided at one of the right and left parts corresponding to one of machine entrances  31   a  to be described later). 
         [0038]    The forme rest  50  is supported by the right and left (paired) slide rails (horizontal movement guide members)  55  to be movable from the aforementioned position (a first position within the liquid coating unit, as indicated by solid lines in  FIG. 2 ) to a second position (a position indicated by dashed double-dotted lines in  FIG. 2 ) within a forme or plate replacing work space S which an operator can go into and out of through the machine entrance  31   a  formed in at least one of the right and left frames  31 . 
         [0039]    The slide rail  55 , as shown in  FIG. 3 , comprises a moving rail  55   a , a stationary rail  55   b , and an intermediate rail  55   c  slidably fitted to both of the moving rail  55   a  and the stationary rail  55   b . The moving rail  55   a  is fixed to the right and left parts of the forme rest  50 , while the stationary rail  55   b  is fixed to the pair of (i.e., right and left) L-shaped angle members  56  laid in the fore-and-aft direction on the bed  30 . 
         [0040]    The slide rail  55  has a locking mechanism (not shown) for locking and unlocking in the most contracted state at the first position within the liquid coating unit, and in the most extended state at the second position within the forme replacing work space S. 
         [0041]    Because of the above-described features, the following work procedure is performed in replacing the screen printing forme  35  for printing a different printing product: 
         [0000]    (1) First of all, the operator enters the forme replacing work space S through the machine entrance  31   a , and then while pressing the used screen printing forme  35 , operates a switch for moving the tubular end members  34  at the opposite ends of the rotary screen cylinder  32  outwards by driving of the motors  40 , thereby moving the tubular end members  34  outwards, and also detaching the used screen printing forme  35  from the tubular end members  34 . Then, the operator places the used screen printing forme  35  on the inclined surfaces  52   a  of the forme bearers  52  of the ink pan  53  placed on the forme rest  50 .
 
(2) Then, the operator grasps the withdrawing grips  51 , and moves the forme rest  50 , together with the ink pan  53 , from the first position within the liquid coating unit toward the second position within the forme replacing work space S. During this movement, the operator goes out of the forme replacing work space S through the machine entrance  31   a.  
 
(3) Then, the operator removes the used screen printing forme  35  placed on the ink pan  53  on the forme rest  50  located at the second position within the forme replacing work space S. On this occasion, if the screen printing forme  35  is severely soiled, for example, the pull-out grips  54  may be grasped, and the screen printing forme  35  may be taken out of the machine together with the ink pan  53 .
 
(4) Then, the operator places another screen printing forme  35 , which is used in subsequent printing, on the inclined surface  52   a  of the forme bearers  52  of the ink pan  53  on the forme rest  50 .
 
(5) Then, the operator grasps the withdrawing grips  51 , and moves the forme rest  50 , together with the ink pan  53 , from the second position within the forme replacing work space S to the first position within the liquid coating unit.
 
(6) Finally, the operator enters the forme replacing work space S through the machine entrance  31   a , and while pressing the screen printing forme  35  to be used in subsequent printing, operates a switch for moving the tubular end members  34  at the opposite ends of the rotary screen cylinder  32  inwards by driving of the motors  40 , thereby moving the tubular end members  34  inwards, and also allowing the tubular end members  34  to support the screen printing forme  35  to be used in subsequent printing.
 
         [0042]    Since the screen printing forme  35  is replaced in the above-mentioned manner, one operator is enough to perform the work of replacing the screen printing forme  35  easily, by using the forme rest  50 , even if the forme replacing work space S or the machine entrance  31   a  of the frame  31  is narrow, in other words, without the need to widen the space S or the entrance  31   a . Moreover, the machine can be downsized. 
         [0043]    Furthermore, since the ink pan  53  is present, it brings the advantages that it can serve as an ink receptacle if an ink scatter, for example, occurs during printing, and that it can be carried to a utility room without the need for holding a dirty screen printing forme  35  at the time of replacement. Of course, the ink pan  53  may be omitted. 
         [0044]    In the present embodiment, the forme rest  50  may be automatically withdrawn by an air cylinder or the like, instead of being withdrawn by the withdrawing grips  51 . 
         [0045]    Moreover, the horizontal movement guide member, such as a mere slide table, other than the slide rails  55 , may be used. 
       Embodiment 2 
       [0046]      FIG. 4  is an explanation drawing using a four-joint link and a drive means (air cylinder) showing Embodiment 2 of the present invention. 
         [0047]    This is an embodiment in which the forme rest  50  can be moved between the first position within the liquid coating unit and the second position within the forme replacing work space S by air cylinders (drive means)  58  via four-joint links  57  instead of the slide rails  55  as the horizontal movement guide members of Embodiment 1. 
         [0048]    The above feature obtains the advantage that the replacing work can be performed more promptly, in addition to the same actions and effects as those in Embodiment 1. 
         [0049]    In the present embodiment, it is possible to substitute the air cylinder  58  by a gas damper without using the air cylinder  58 , attach an operating lever to the fulcrum, and provide a stopper at the position of attachment and detachment, thereby converting the mode of operation into a manual mode. 
       Embodiment 3 
       [0050]      FIGS. 5A and 5B  are explanation drawings using rolling bodies (rollers) showing Embodiment 3 of the present invention. 
         [0051]    This is an embodiment in which many rollers (rolling bodies)  60  are discretely arranged in the longitudinal direction on the forme bearers  52  of Embodiment 1. 
         [0052]    The above feature obtains the advantage that the screen printing forme  35  can be easily withdrawn from and placed in the machine, in addition to the same actions and effects as those in Embodiment 1. 
         [0053]    While the present invention has been described in the foregoing fashion, it is to be understood that the invention is not limited thereby, but may be varied in many other ways. For example, the present invention can be applied to machines other than the rotary screen printing press, such as a stencil printing press and a coating machine for supplying varnish instead of ink and performing coating instead of printing. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the appended claims.

Technology Classification (CPC): 1