In the drawings:
A variable printing machine according to the present invention is explained with reference to
In the path of travel of continuous paper 10 between the upstream and downstream side rollers 1 and 2, a plurality of (here, four) printing units 3a, 3b, 3c and 3d each comprising a printing, a blanket and an impression cylinder 4, 5 and 6 and made capable of variable printing are shown arranged. The printing and blanket cylinders 4 and 5 in each printing unit 3a, 3b, 3c, 3d are designed to rotate at an identical peripheral speed. And, though not shown in
In the form of implementation shown in
And, in this form of implementation, the blanket and printing cylinders 5 and 4 in each exchange cylinder unit are coupled together but the impression cylinder 6 therein is rotationally driven by a motor whose rotation is controllable independently.
At the upstream and down stream sides of the impression cylinder 6 in each printing unit 3a, 3b, 3c, 3d there are arranged guide rollers 14a and 14b, respectively, by which continuous paper 10 to run between the blanket and impression cylinders 5 and 6 in each printing unit 3a, 3b, 3c. 3d is to be wound on the impression cylinder at a certain angle of winding.
Further, the guide rollers 14a and 14b while being coupled to the impression cylinder 6 in each printing unit 3a, 3b, 3c, 3d is designed to rotate at an identical peripheral speed of, and synchronously with, this impression cylinder 6.
Also, at respective one ends of the guide rollers 14a and 14b and at positions corresponding to the pulleys 15 and 16 for the impression cylinder 6, there are fastened driven timing pulleys 17a and 17b and driven V pulleys 18a and 18b so that the pulleys 17a and 17b are juxtaposed to the pulleys 18a and 18b, respectively. Further, spaced from and parallel to the guide rollers 14a and 14, there are provided tension timing pulleys 19a and 19b and tension V pulleys 20a and 20b so that the pulleys 19a and 19b are juxtaposed to the pulleys 20a and 20b, respectively and the pulleys 19a, 20a and pulleys 19b, 20b lie coaxially and rotatably with supporting shafts 21a and 21b, respectively, which are provided on the main machine body. And, at least one of the supporting shafts 21a and 21b, e.g., 21a are designed to be movable in position relative to the other, e.g., 21b, in a far and near direction.
A timing belt 22 of double faced type is wound on the driving timing pulley 15 provided for the impression cylinder 6, the driven timing pulleys 17a and 17b provided for the guide rollers 14a and 14b and both the tension timing pulleys 19a and 19b so that as shown in
Also, a V belt 23 of double faced type is wound on the driving V pulley 16 provided for the impression cylinder 6, the driven V pulleys 18a and 18b provided for the guide rollers 14a and 14b and both the tension V pulleys 20a and 20b so that as shown in
The tension of the timing belt 22 and the V belt 23 is adjusted by shifting the position of one supporting shaft 21a to shift the position of the tension timing pulley 19a and the tension V pulley 20a which are supported by the shaft 21a.
The driving timing pulley 15 and the driving V pulley 16 which are provided for the impression cylinder 6 are made identical in pitch circle diameter to each other. The driven timing pulley 17a and the driven V pulley 18a which are provided for the guide roller 14a are made identical in pitch circle diameter to each other. Likewise, the driven timing pulley 17b and the driven V pulley 18b which are provided for the other guide roller 14b are made identical in pitch circle diameter to each other. And, the driving timing pulley 15 and the driving V pulley 16 provided for the impression cylinder 6, the driven timing pulley 17a and the driven V pulley 18a provided for the guide roller 14a, and the driven timing pulley 17b and the driven V pulley 18b provided for the other guide roller 14b have a ratio between their pitch circle diameters which is made identical to a ratio between the outer diameters of the impression cylinder 6, the guide roller 14a and the guide roller 14b. The guide rollers 14a and 14b are driven via the respective belts by the impression cylinder 6 to rotate at a peripheral speed which is identical to that of the impression cylinder 6.
The tension timing pulleys 19a and 19b respectively provided on the supporting shafts 21a and 21b are identical in pitch circle diameter to the tension V pulleys 20a and 20b, respectively.
With the makeup mentioned above, between the feed rollers 1 and 2 continuous paper 10 is passed between the respective blanket and impression cylinders 5 and 6 in the printing units 3a to 3d. Then, continuous paper 10 is wound on each impression cylinder 6 at a certain angle of winding via the guide roller 14a at its upstream side and the guide roller 14b at its downstream side.
Now, the feed rollers 1 and 2 and the impression cylinder 6 in each printing unit 3a, 3b, 3c, 3d are normally or reversely rotated, linked with an operation of the printing unit 3a, 3b, 3c, 3d. To wit, continuous paper 10 is fed normally to travel over a peripheral length of the larger diameter section of the blanket cylinder 5 in the printing unit 3a, 3b, 3c, 3d and fed reversely by an extra length of travel in the normal direction corresponding to non-image bounds.
Since the impression cylinder 6 and the guide rollers 14a and 14b are then controllably rotated at an identical peripheral speed and synchronously with a direction and a rate of travel of continuous paper 10, it follows that continuous paper 10 held wound on the impression cylinder 6 at the given angle is guided by the impression cylinder 6 to travel normally or reversely.
Thus, even during the time the smaller diameter section of the blanket cylinder 5 is opposed to the impression cylinder 6 in each printing unit 3a, 3b, 3c, 3d so continuous paper 10 is thus not nipped with the blanket cylinder 5, it follows that continuous paper 10 while held wound on the impression cylinder 6 is fed to travel reversely. Thus, continuous paper 10 is prevented from loosening or fluttering which has been experience when it is not under a nipping action by the blanket cylinder 5 whose smaller diameter portion is opposed thereto.
And then, since the guide rollers 14a and 14b which serve to guide continuous paper 10 ahead and behind each printing unit 3a, 3b, 3c, 3d are driven to rotate synchronously with, and at an identical peripheral speed to that of, the impression cylinder 6, continuous paper 10 is allowed to travel without slipping on the guide rollers 14a and 14b.
While operating as above, the guide rollers 14a and 14b provided at both sides in continuous paper traveling direction of the impression cylinder 6 are driven in a double drive system by the timing belt 22 and the V belt 23.
And, in this belt driving by the impression cylinder 6, between the driving timing pulley 15 for the impression cylinder 6 and the timing belt 22 wound thereon at the time of switch-over between normal and reverse rotations of the impression cylinder 6 an impact force develops which tends to cause a momentary slip to occur, assisted by backlash at an area where the timing pulley 15 and the timing belt 22 engage with each other and by elasticity of the timing belt. As a result, continuous paper 10 each time its traveling direction is switched is adversely affected such as by its fluttering.
However, with the impression cylinder 6 provided with the driving pulley 16 juxtaposed, on which is wound the V belt 23 wound on the V pulleys 18a and 18b fastened to the guide rollers 14a and 14b, the frictional driving force which this belt creates causes the slip occurring between the timing pulley 15 and the timing belt 23 to be absorbed and relieved, thereby inhibiting continuous paper 10 from fluttering each time its travel direction is switched.
While it is required that the timing pulleys 15, 17a, 17b, 19a, 19b and the V pulleys 16, 18a, 18b, 20a, 20b be identical in their pitch circle diameters as for their respective axes, as a matter of fact a machining error of each of these pulleys makes it difficult to make them identical in their pitch circle diameters.
For this reason, the V pulleys 16, 18a, 18b, 20a and 20b are made as shown in
While in the form of implementation shown in
In this alternative form of implementation, the guide rollers 14a and 14b are driven by the parallel V belts at axially both ends and being especially fine in diameter are thereby kept from behavior of becoming twisted so as to allow continuous paper to run stably through a region of these guide rollers.
In the form of implementation shown in
According to this form of implementation, the guide rollers 14a and 14b as well as the impression cylinder 6 are motor-driven individually, with motors 13a and 13b while they at their other end side are rotationally driven without becoming twisted by the V belt 23. And, in this form of implementation, guide rollers which besides guide rollers 14a and 14b for each printing unit 3a, 3b, 3c, 3d include guide rollers 14c and 14d provided, respectively, at the downstream side of the upstream side feed roller 1 and at the upstream side of the down-stream side feed roller 2 as shown in
While in the forms of implementation mentioned above the printing units 3a to 3d are described as being of offset type, suffice it to say that each of them may be of direct printing type without using the blanket cylinder.
Also, in the forms of implementation mentioned above, the guide roller means may not necessarily be two guide rollers 14a and 14b which are used at the upstream and downstream sides of an impression cylinder 6, respectively. What is essential is its capability of winding continuous paper 10 on the impression cylinder 6 and it may be provided at one of the sides.
Further, each of the printing units 3a to 3d may as shown in
Number | Date | Country | Kind |
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JP 209581/2006 | Aug 2006 | JP | national |