Patent Publication Number: US-6336400-B1

Title: Stencil printing machine

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a stencil printing machine for bringing an ink supply roller wherein ink is supplied onto its outer peripheral surface into contact with the inner peripheral surface of a printing drum and transferring the ink which has permeated through a stencil sheet to a sheet, thereby printing on the sheet, and relates in particular to an improvement in a structure for setting up a printing drum unit to the body of a printing machine, and a structure for supplying ink to an ink supply roller. 
     2. Description of the Related art 
     In a stencil printing machine, a printing drum on which a stencil sheet is wound around is set up to the body of a printing machine in the manner that the drum can be freely put on and taken off. In this way, the stencil printing machine is made to cope with the sort of printing color or maintenance. As shown in FIG. 1, an ink supply roller  3  is arranged inside a printing drum  1 . The outer peripheral surface of the ink supply roller  3  is brought into contact with the inner peripheral surface of the printing drum  1 . An ink amount control member (doctor rod)  5  is also arranged inside the printing drum  1  in the manner that the member  5  is located at a given interval from the outer peripheral surface of the ink supply roller  3  and in parallel to the roller  3 . In this manner, a wedge-form ink pool  7  is made between the outer peripheral surface of the ink supply roller  3  and the outer peripheral surface of the ink amount control member  5  to be sandwiched therebetween. 
     An ink driving rod  9 , which is in parallel to the ink supply roller  3 , is rotatably arranged inside the ink pool  7 . A non-illustrated gear fitted to one end of the ink driving rod  9  is engaged with a non-illustrated gear fitted to one end of the ink supply roller  3 , so that the rod  9  can be rotated oppositely to the direction of the rotation of the ink supply roller  3  and in synchronization with the rotation thereof. 
     In operation of the stencil printing machine, the printing drum  1  is rotated in the direction of an arrow A, and the ink supply roller  3  is rotated in the direction of an arrow B. Thus, ink in the ink pool  7  revolves in a whirl around the ink driving rod  9  to produce an ink lump  11 . The ink for producing the ink lump is supplied through an ink supply member (distributer)  13 . 
     As shown in FIG. 2, conventionally, in the printing drum  1  having such a structure, its both ends in the axial direction of the drum  1  are rotatably supported by brackets  15 . The brackets  15  at the two ends are connected with each other through support rods  17 . These brackets  15 , the support rods  17  and the printing drum constitute a printing drum unit  2 . 
     A printing drum receiving section  19  is made in the body of the printing machine. A pressure drum  21  that can be freely rotated is arranged in the printing drum receiving section  19 . A pair of parallel support rails  23  are fixed in the printing drum receiving section  19 . The support rails  23  are positioned to have the same level above the pressure drum  21 . In connection with the printing drum receiving section  19 , openings are made, for example, in a side of the printing machine body and the two support rails  23  are slid and pulled out from the openings. The printing drum unit  2  is once held up and is then brought below the position between the support rails  23 . In this way, the support rods  17  are hung on the support rails  23  so that the printing drum unit  2  can be fitted into the printing drum receiving section  19 . 
     However, in the above-mentioned conventional stencil printing machine, a pair of the support rails in the printing drum receiving section is secured at the same level. Therefore, in order to fit the printing drum unit into the printing drum receiving section, it is unavoidable to hold up the printing drum unit once above the support rails and then bring down the unit, thereby hanging the support rods on the support rails. Thus, large power is necessary so that the printing drum unit cannot easily be fitted. 
     In the case of multicolor printing or color printing, as shown in FIG. 3, plural printing drums  2   a and  2   b must be arranged above the central axis of a pressure drum  21  in a stencil printing machine. However, in the case that ink supply rollers  3  having the same structure are set up, the setting-up angles of the rollers  3  are caused to be different at the right and left printing drum units  2   a and  2   b . Therefore, in the one printing drum unit  2   a , ink from a distributer  13  drops on the ink supply roller  3  to be supplied thereto. In the other printing drum unit  2   b , however, there arises a problem that ink from a distributer  13  comes not to drop on the ink supply roller  3  so as to cause impossibility of supply of the ink. For this reason, in any stencil printing machine wherein plural printing drum units must be set up at different angles, it is difficult to make the printing drum units common. 
     SUMMARY OF THE INVENTION 
     In the light of the above-mentioned situations, the present invention has been made. An object thereof is to provide a stencil printing machine making it possible to set up a printing drum unit easily and further make the printing drum units, if any, common. 
     The stencil printing machine of a first aspect of the present invention comprises : a printing drum unit comprising a printing drum on which a stencil sheet is wound around, a pair of brackets which supports both ends of the printing drum so that the printing drum can be rotated, and at least one pair of support rods which is connected with the pair of the brackets and arranged in the same direction as the axial line of the printing drum; a printing drum receiving section having an opening, at a side position of a printing machine body, through which the printing drum unit can be put on and taken off, whereby the section can receive the printing drum unit; a first support rail which is disposed in the printing drum receiving section and is freely pulled out in a horizontal direction from the opening, whereby the first support rail supports the one support rod; and a second support rail which is disposed below the first support rail in the printing drum receiving section and is freely pulled out in a horizontal direction from the opening, whereby the second support rail supports the other support rod. 
     According to the stencil printing machine of the first aspect, the printing drum unit is moved from a side direction to the pulled-out first support rail so that the one support rod is supported. That is, unnecessary becomes the operation of holding up the printing drum unit once upwards and then bringing down the unit. Moreover, the one support rod is supported so that the printing drum unit is provisionally supported. Thus, this unit can be supported by one hand. In this state, the second support rail is pulled out and the other support rod is supported by the second support rail, so that the pair of the support rods is supported by the first and second support rails. In this way, setting-up of the printing drum unit is completed. 
     On the other hand, the stencil printing machine of a second aspect of the present invention comprises: a printing drum unit comprising a printing drum on which a stencil sheet is wound around, a pair of brackets which supports both ends of the printing drum so that the printing drum can be rotated, and at least one pair of support rods which is connected with the pair of the brackets and arranged in the same direction as the axial line of the printing drum; a printing drum receiving section having an opening, at a side position of a printing machine body, through which the printing drum unit can be put on and taken off, whereby the section can receive the printing drum unit; a first support rail which is disposed in the printing drum receiving section and is freely pulled out in a horizontal direction from the opening, whereby the first support rail supports the one support rod; a second support rail which is disposed below the first support rail in the printing drum receiving section and is freely pulled out in a horizontal direction from the opening, whereby the second support rail supports the other support rod; an ink supply roller which is disposed inside the printing drum and whose outer peripheral surface is brought in contact with the inner peripheral surface of the printing drum, whereby the ink supply roller is rotated; an ink supply member which is disposed inside the printing drum to jet out ink; and an ink guide roller which is positioned between the ink supply member and the ink supply roller to deliver the ink supplied from the ink supply member to the ink supply roller. 
     The stencil printing machine of the second aspect exhibits the same effect as the stencil printing machine of the first aspect. Moreover, the ink supplied from the ink supply member is delivered to the ink supply roller through the ink guide roller, so as to remove any restriction on the printing drum setting-up angle, which is essential for conventional ink supply structures in which ink is caused to drop freely. In this way, the direction along which the printing drum unit is set up becomes unrestricted so that, in any stencil printing machine having a plurality of the printing drum units, the printing drum units can be made common. 
     Other and further objects and features of the present invention will become obvious upon understanding of the illustrative embodiments about to be described in connection with the accompanying drawings or will be indicated in the appended claims, and various advantages not refereed to herein will occur to one skilled in the art upon employing of the invention in practice. 
    
    
     BRIEF DESCRIPTION THE DRAWINGS 
     FIG. 1 is a perspective view illustrating an ink supply state in a conventional stencil printing machine. 
     FIG. 2 is a side view illustrating the position where a printing drum unit is set up in the conventional stencil printing machine. 
     FIG. 3 is a side view illustrating plural printing units set up in a conventional stencil printing machine. 
     FIG. 4 is a side view of a printing drum receiving section in a stencil printing machine according to the present invention. 
     FIG. 5 is a front view illustrating a structure for connecting a printing drum unit and the body of the printing machine. 
     FIG. 6 is a front view illustrating a structure for connecting the central axis of the printing drum and a shaft bearing of the body. 
     FIG. 7 is a side view of an end portion of the printing drum unit. 
     FIG. 8 is a perspective view illustrating a structure for connecting a driving axis and a trailing axis. 
     FIG. 9 is a side view illustrating an ink supply structure of the stencil printing machine according to the present invention 
     FIG. 10 is a side view illustrating a drive transmission mechanism of the ink supply structure illustrated in FIG.  9 . 
     FIG. 11 is a perspective view illustrating a drive transmission mechanism of an ink guide roller. 
     FIGS. 12A,  12 B and  12 C are views illustrating a process for setting up the printing drum unit of the stencil printing machine according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Various embodiments of the present invention will be described with reference to the accompanying drawings. It is to be noted that the same or similar reference numerals are applied to the same or similar parts and elements throughout the drawings, and the description of the same or similar parts and elements will be omitted or simplified. 
     Referring to the drawings, the following will in detail describe preferred embodiments of the stencil printing machine according to the present invention. 
     FIG. 4 is a side view of a printing drum receiving section in a stencil printing machine according to the present invention. FIG. 5 is a front view illustrating a structure for connecting a printing drum unit and the body of the printing machine. FIG. 6 is a front view illustrating a structure for connecting the central axis of the printing drum and a shaft bearing of the body. FIG. 7 is a side view of an end portion of the printing drum unit. FIG. 8 is a perspective view illustrating a structure for connecting a driving axis and a trailing axis. 
     As illustrated in FIG. 4, each of printing drums  31 , on which a stencil sheet is wound around, is rotatably supported, at its both ends in the axial direction of the drum, by a pair of flange-form brackets  33 . The pair of the brackets  33  is connected with each other through a pair of support rods  35  arranged in the same direction as the axial line of the printing drum  31 . The number of the needed support rods  35  is at least two. Of course, the number of the used support rods  35  may be three or more, in order to make connection strength higher. A printing drum unit  30  is composed mainly of the brackets  33 , the support rods  35  and the printing drum  31 . 
     Printing drum receiving sections  37  are formed in a non-illustrated printing machine body. Each of the printing drum receiving sections  37  can receive the printing drum  31 . A pressure drum  41  that can be freely rotated is arranged in the printing machine body. In the printing drum unit  30  received in the printing drum receiving section  37 , the outer periphery of the printing drum  31  contacts the outer periphery of the pressure drum  41 . Openings  39  (see FIG. 12) for putting on and taking off the printing drum units  30  are made in the printing drum receiving sections  37 , that is, in a side position of the printing machine body. In this embodiment, the two printing drum units  30  are set up above the pressure drum  41 . Therefore, the side of the printing machine body has the two openings  39 . 
     The printing drum receiving section  37  is provided with a first support rail  43 . The first support rail  43  can be freely pulled out in a horizontal direction (the direction perpendicular to the paper surface of FIG. 4) from the opening  39 . An engaging plate  45  having, for example, an L-shaped section is fixed to the side face, opposite to the printing drum  31 , of the first support rail  43 . The engaging plate  45  can engage with one support rod  35  in the printing drum unit  30 . That is, the first support rail  43  is pulled out from the opening  39  and the single support rod  35  is engaged with the engaging plate  45 , so that one side of the printing drum unit  30  can be supported by the printing machine body. In this state, the printing drum unit  30  can be supported by one hand. 
     The printing drum receiving section  37  has a second support rail  47  at a position opposite to the printing drum  31  from the first support rail  43 . The second support rail  47  can be freely pulled out in a horizontal direction from the opening  39 , too. This second support rail  47  is arranged at a position below the first support rail  43  in the printing drum receiving section  37 . An engaging plate  45  having an L-shaped section is fixed to the side face, opposite to the printing drum  31 , of the second support rail  47 . This engaging plate  45  can engage with the other support rod  35  in the printing drum unit  30 . That is, the second support rail  47  is pulled out from the opening  39  and the other support rod  35  is engaged with the engaging plate  45 , so that the whole of the printing drum unit  30  can be supported by the printing machine body. In this sate, the printing drum unit  30  can be supported, without support by any hand, by the printing machine body. 
     As illustrated in FIG. 5, the printing drum  31  is rotatably supported by a printing drum central axis  53  in the manner that its both ends are held through axis bearings  51  by the printing drum central axis  53 . This printing drum central axis  53  is supported by the above-mentioned brackets  33  and is projected outwards from the brackets  33 . An axis bearing  57  is fixed to a side plate  55 , which is present at the side of the print machine body, of the printing drum receiving section  37 . The printing drum central axis  53  is fitted into the axis bearing  57 . 
     As illustrated in FIG. 6, a flexible fixing plate  59  is set up onto the side of the axis bearing  57 . A part of the fixing plate  59  is projected into a fitting hole of the axis bearing  57 . A fixing groove  61  is made in the outer periphery at the tip side of the printing drum central axis  53 , so that the fixing grove  61  can engage with the fixing plate  59 . Therefore, by inserting the printing drum unit  30  into the printing drum receiving section  37 , the printing drum central axis  53  is inserted into the axis bearing  57 . By engaging the fixing grove  61  with the fixing plate  59 , the printing drum unit  30  is fixed to the printing machine body. The fixing plate  59  can be moved by  35  a non-illustrated fixation releasing means. At the time of putting on and taking off the printing drum unit  30 , the engagement of the fixing plate  59  with the fixing groove  61  can be released. 
     As illustrated in FIG. 7, external gears  65  are made in both ends in the axial direction of the printing drum  31 , and the external gears  65  are engaged with printing drum driving gears  67  located near the outer periphery of the printing drum  31 . As illustrated in FIG. 5, the printing drum driving gear  67  is secured to a trailing axis  69  in the same direction as the axial line of the printing drum  31 . The trailing axis  69  is rotatably supported, at its both ends, by the above-mentioned pair of brackets  33 . As illustrated in FIG. 8, an engaging portion  71  having projections  71   a from its outer periphery is formed on the tip portion, which is present at the side of the side plate  55 , of the trailing axis  69 . A driving axis  73  is fitted, at a position corresponding to the trail axis  69 , to the side plate  55 . An engaging hole  75  which engages with the engaging portion  71  is made in the tip portion of the driving axis  73 . When the printing drum unit  30  is set up in the printing drum receiving section  37 , the engaging portion  71  of the trailing axis  69  is fitted into the engaging hole  75 . In this way, the trailing axis  69  is connected with the driving axis  73  in such a manner that they do not rotate relatively. As a result, driving power is transmitted from the printing machine body. 
     The following will describe an ink supply structure. set up inside the printing drum, on the basis of FIGS. 9-11. FIG. 9 is a side view illustrating an ink supply structure of the stencil printing machine according to the present invention. FIG. 10 is a side view illustrating a drive transmission mechanism of the ink supply structure illustrated in FIG.  9 . FIG. 11 is a perspective view illustrating a drive transmission mechanism of an ink guide roller. 
     An ink supply roller  81  is located inside the printing drum  31 . The outer peripheral surface of the ink supply roller  81  is brought into contact with the inner peripheral surface of the printing drum  31 . Inside the printing drum  31 , an ink supply member (distributer)  83  for jetting out ink is arranged at an interval from the printing drum  31 . An ink guide roller  85  is positioned between the ink supply roller  81  and the distributer  83 . The ink guide roller  85  is located between the distributer  83  and the ink supply roller  81  and at a very small interval therefrom making delivery of ink possible. That is, the ink supplied from the distributer  83  is supplied through the ink guide roller  85  to the ink supply roller  81 . 
     In this ink supply structure, which is different from conventional ink supply structures of an ink-drop type, the distributer  83  is positioned at a very small interval from the ink guide roller  85 . Therefore, the ink supply from the distributer  83  does not depend on an ink-drop direction. It is therefore unnecessary to regulate the angle at which the printing drum  31  is set up in the manner that the ink drop direction becomes substantially vertical direction. 
     Inside the printing drum  31 , an ink amount control member (doctor rod)  87  is arranged at a given interval from the outer peripheral surface of the ink supply roller  81  and in parallel to the ink supply roller  81 . In this way, an ink pool  89  is formed between the outer peripheral surface of the ink supply roller  81  and the outer peripheral surface of the ink amount control member  87  so as to be sandwiched therebetween. Inside this ink pool  89 , an ink driving rod  91  is rotatably arranged in the parallel to the ink supply roller  81 . 
     As illustrated in FIG. 10, a printing drum gear  93  having an axis equal to that of the printing drum  31  is secured inside the printing drum  31 . The printing drum gear  93  is rotated in the synchronization with the rotation of the printing drum  31 . A supply roller gear  95  is secured to the end of the axis of the ink supply roller  81 . A middle gear  97  is being engaged with the supply roller gear  95  and the printing drum gear  93 . That is, motive power is transmitted from the printing drum gear  93  to the ink supply roller  81  through the middle gear  97 , so that the roller  81  is driven and rotated in synchronization with the printing drum  31 . 
     A non-illustrated gear fixed to one end of the ink driving rod  91  is being engaged with the supply roller gear  95  of the ink supply roller  81 , so that the rod  91  is reversibly rotated in synchronization with the rotation of the ink supply roller  81 . 
     As illustrated in FIG. 11, a guide roller gear  99  is secured to an end portion of the ink guide roller  85 . A drive transmitting gear  101  is being engaged with the supply roller gear  95  and the guide roller gear  99 . Therefore, motive power is transmitted from the supply roller gear  95  to the ink guide roller  85  through the drive transmitting gear  101 , so that the roller  85  is driven and rotated in synchronization with the ink supply roller  81 . A non-illustrated rotation direction regulating member (one-way clutch) is set up to the guide roller gear  99 , so that the rotation of the ink guide roller  85  is regulated to one direction. 
     The following will describe a process for setting up the printing drum of the stencil printing machine having such a structure on the basis of FIGS. 12A-C. FIGS. 12A-C are views showing a process for setting up the printing drum of the stencil printing machine according to the present invention. 
     As illustrated in FIG. 12A, in order to set up the printing drum unit  30 , the first support rail  43  is first pulled out from the opening  39  of the printing machine body  105 . Next, the one support rod  35  of the printing drum unit  30  is engaged with the engaging plate  45  of the first support rail  43 . At this time, the second support rail has not yet been pulled out, so that the printing drum unit  30  is moved from a side direction without being disturbed by the second support rail  43  to engage with the first support rail  47 . In this way, the printing drum unit  30  is provisionally supported by the printing machine body  105  so that the unit  30  can be supported by one hand. 
     As illustrated in FIG. 12B, next, the second support rail  47  is pulled out by the other hand. When the second support rail  47  is pulled out, the printing drum unit  30  is rotated in the direction shown by an arrow around the support rod  35  that has already been supported by the engaging plate  45  as illustrated in FIG.  4 . Moreover, in this way, the support rod  35  that has not yet been supported is engaged with the engaging plate  45  of the second support rail  47 . Since at this time the second support rail  47  is arranged below the first support rod  43 , the printing drum unit  30  can easily be supported by the second support rail  47  only by rotating and moving the printing drum unit  30  downwards. In this way, the printing drum unit  30  is supported by the printing machine body  105  through the first and second support rails  43  and  47 , as illustrated in FIG.  12 C. At last, the first and second support rails  43  and  47 , through which the printing drum unit  30  is supported, together with the printing drum unit  30 , are slid and moved to the printing drum receiving section  37  and are received in the section  37 . In this way, the setting-up of the printing drum unit  30  is completed. 
     The printing drum unit  30  can be taken off from the printing machine body  105  by the process reverse to the above-mentioned process. 
     As described above, according to the above-mentioned stencil printing machine, the printing drum unit  30  is moved from a side direction to the pulled-out first support rail  43  so that the one support rod  35  is supported. That is, unnecessary becomes the operation of holding up the printing drum unit  30  once in the direction over the support rail and then bringing down the unit  30 . Moreover, the one support rod  35  is supported so that the printing drum unit  30  is provisionally supported. Thus, the unit  30  can be supported by one hand. In this state, the second support rail  47  is pulled out and the printing drum unit  30  is rotated and moved downwards, so that the unit  30  can easily be supported by the second support rail. In this way, it becomes possible to set up the printing drum unit  30  easily. 
     The first and second support rails  43  and  47  may have a structure so as to be pulled out at the same time. 
     The ink supplied from the distributer  83  is delivered to the ink supply roller  81  through the ink guide roller  85 , so as to remove any restriction on the printing drum setting-up angle, which is essential for conventional ink supply structures in which ink is caused to drop freely. In this way, the direction along which the printing drum unit  30  is set up becomes unrestricted so that, in any stencil printing machine having a plurality of the printing units  30 , the printing drum unit  30  can be made common. 
     OTHER EMBODIMENTS 
     Various modifications will become possible for those skilled in the art after receiving the teachings of the present disclosure without depending from the scope thereof. 
     As described above, of course, the present invention includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the following claims that are proper in the light of the above description.