JPH0451456B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for adjusting the paper feeding speed of the printing section in a form printing machine that continuously performs processes such as printing, punching, perforation, etc. It is.

(Prior Art) The overall configuration of a foam printing machine is shown in FIG. 9. In the figure, 1 is a rolled paper P
2 is a printing section that performs offset printing on the fed paper P; 3 is a processing section that performs punching, perforation, etc. on the printed paper P that is fed out from this first printing; 4 is a paper ejection unit that takes out the printed and processed paper P while folding it in a zigzag manner.

The printing section 2 consists of a number of printing units (here, four printing units in the case of four-color printing) 5 arranged in parallel on a printing line according to the number of printing colors.
passes through each of these printing units 5 sequentially and is printed in multiple colors. Each printing unit 5 has a plate cylinder 6, a blanket cylinder 7 made of an elastic material such as rubber that copies the image on the plate cylinder 6, and a metal impression cylinder 8, which are in contact with each other around the circumference. It is rotatably supported by a printing cylinder support pair 9.
The paper P passes between the blanket cylinder 7 and the impression cylinder 8, and at this time, the pattern transferred from the plate cylinder 6 to the blanket cylinder 7 is printed on the paper P.

The rotational force of a drive motor (not shown) is transmitted to each printing unit 5 via a drive shaft 11, as shown in FIG. The drive shaft 11 is provided across all the printing units 5 of the paper feeding section 1 and the printing section 2, and the rotational force of this drive shaft 11 is transmitted to the infield roll 10 via a transmission device 12 such as a worm gear mechanism. It is transmitted to the forme cylinder 6 of each printing unit 5 via a transmission 13 .

As shown in FIG. 7, each rotation shaft 6a of the plate cylinder 6, blanket cylinder 7, impression cylinder 8 of each printing unit
7a and 8a have spur gears 14, 15, and 16, respectively.
The rotational force of the drive shaft 11 is transmitted to the plate cylinder 6, blanket cylinder 7, and impression cylinder 8 by the meshing rotation of these spur gears 14, 15, and 16.
This allows each of these cylinders 6, 7, and 8 to rotate.

In this case, the feeding speed of the paper P in the printing unit 5 (hereinafter referred to as paper feeding speed) is controlled by the rotational speed of the blanket cylinder 7 and the impression cylinder 8, but it also changes depending on the paper thickness. . That is, in FIG. 8, d is the diameter of the impression cylinder 8, and N
is the same number of rotations, t is the paper thickness, and the paper feed speed V is given by V = N (d + t) π. The paper feed speed V becomes faster as the paper thickness t increases, and the paper feed amount per unit time is To increase.

In addition, in the blanket cylinder 7, changes in paper thickness are absorbed by changes in cylinder diameter due to elasticity, so changes in paper feeding speed are absorbed by the impression cylinder 8, which does not deform elastically.
This is caused by the relationship between paper thickness and paper thickness. In other words,
The paper feed speed is determined by the rotation speed of the impression cylinder and the paper thickness. In addition, the paper thickness t generally changes in the range of 0.05 mm to 0.2 mm in business form printing machines, so the paper feed speed V is as follows: Minimum value Vmin=N(d+0.05)π Maximum value Vmax=N( d+0.2)π.

However, in conventional printing presses, the impression cylinder 8 is always rotated at a constant speed together with the blanket cylinder 7 regardless of the change in paper thickness as described above, so paper feed may be affected by changes in paper thickness. Due to the change in speed, the following problems arose:

(b) Regardless of whether it is one-color printing or multi-color printing, printing precision varies due to changes in paper feed speed (changes in printing pitch) with respect to the blanket cylinder 7, which continues to rotate at a constant speed, in the printing unit 5. occurs.

(b) Since the printing pitch changes, the printing section 2
Since the tension of the paper P changes between the paper P and the paper feed section 1 at the front stage or the processing section 3 at the rear stage, a large tension acts on the paper P and the paper feeding mechanism, causing breakage of the paper P and the lifespan of the paper feeding mechanism. causing a decline.

Furthermore, in multicolor printing, variations in the impression cylinder diameter of each printing unit 5 cause a difference in paper feed speed between each unit, that is, a deviation in printing pitch, so this also causes the same problem as above. There was a problem.

(Object of the Invention) Therefore, the present invention provides a paper feed system for a printing unit in a form printing machine that can prevent fluctuations or deviations in printing pitch by adjusting the paper feed speed in the printing unit according to changes in paper thickness, etc. A regulating device is provided.

(Structure of the Invention) According to the present invention, a printing unit of a printing section is constituted by a plate cylinder, a blanket cylinder, and an impression cylinder, and each cylinder has a rotational force transmitting means provided on its respective rotation shaft. In a form printing machine configured to sequentially transmit rotational force from the same driving source through the blanket cylinder, the rotational force transmission means for the blanket cylinder;
A speed change means is provided between the impression cylinder and the rotational force transmission means for changing the rotational speed of the impression cylinder independently of the plate cylinder and the blanket cylinder.

With this configuration, the rotational speed of the impression cylinder in the printing unit, that is, the paper feed speed, can be adjusted according to changes in paper thickness, variations in the impression cylinder diameter of each printing unit in a multicolor printing machine, etc., and thereby printing This makes it possible to maintain the pitch in an appropriate state.

(Example) An example of the present invention is shown in FIGS. 1 to 5. In this embodiment, a multicolor printing machine shown in FIG. 9 is used as an example. Further, in this embodiment, the same parts as those shown in FIGS. 6 to 9 are denoted by the same reference numerals, and redundant explanation thereof will be omitted.

First, the overall outline of this apparatus will be explained with reference to FIG. The rotational force of the drive shaft 11 is transmitted to the infeed roll 10 via the transmission device 12 as in the conventional case, and is also transmitted to the plate cylinder 6 of each printing unit 5 via the transmission device 13 . In each printing unit 5, the rotational force of the plate cylinder 6 is directly transmitted to the blanket cylinder 7.
The rotational force is transmitted to the impression cylinder 8 via the differential device 20 as a transmission means. The differential device 20 allows the rotational speed of the impression cylinder 8 to be adjusted independently of the plate cylinder 6 and the blanket cylinder 7, thereby making it possible to adjust the feeding speed of the paper P.

Including this differential device 20, each printing unit 5
The specific configuration of the power transmission system will be explained with reference to FIG.

The rotation shaft 6a of the plate cylinder 6 and the blanket cylinder 7,
Spur gears 14 and 15 are respectively attached to 7a so as to mesh with each other. On the other hand, two spur gears 21 and 22 are attached to the rotation shaft 8a of the impression cylinder 8.
One spur gear 21 is the spur gear 1 of the blanket body 7.
It is meshed with 5. A spur gear (hereinafter referred to as a transmission gear) 21 is connected to the rotating shaft 8a via a bearing 23, and a spur gear (hereinafter referred to as an output gear) 22
are directly attached to the rotating shaft 8a, respectively, and a differential gear 20 is provided between both gears 21 and 22.

The configuration and operating principle of the differential gear 20 will be explained with reference to FIGS. 2 to 4. This differential device 20 is called a harmonic drive, and the main body includes an elliptical wave generator 24 and a flex spline 25 that is bent into an elliptical shape by the rotation of the wave generator 24. and a pair of circular splines 26 and 27 having internal peripheral teeth that mesh with the long axis of this flexspline 25, one circular spline 26 connects the spur gear 28 to the transmission gear 21, and the other circular spline 26 Circular splines 27 mesh with output gears 22 via spur gears 29, respectively. The wave generator 24 is attached to an adjustment shaft 30 so as to be able to rotate integrally with this shaft 30, and is rotationally driven by an adjustment motor 32 via the adjustment shaft 30 and a belt transmission mechanism 31. The rotational force of the transmission gear 21 is transferred to the spur gear 28
→ Circular spline 26 → Flex spline 25 → Circular spline 27 → Spur gear 29
The signal is transmitted to the output gear 22 via the path . On the other hand, the rotational force of the adjustment motor 32 is
It is transmitted from the adjustment shaft 30 to the wave generator 24, and due to the rotation of the wave generator 24, the flex spline 25 is deformed into an elliptical shape, and its long axis portion is connected to the circular splines 26, 2.
It sequentially meshes with the internal teeth of No. 7. In this case, the number of teeth of the flex spline 25 is the same as that of the circular spline 2.
Since the number of teeth is several (for example, two) fewer than the number of teeth 6 and 27, the flexspline 25 moves in the opposite direction to the rotational direction of the wave generator 24 by that amount. This movement is extracted as actuation output by the output gear 22, which causes the impression cylinder 8 to rotate at a speed set by the differential 20. The output rotational speed of the differential device 20 can be freely changed by adjusting the rotational speed of the adjustment motor 32, whereby each printing unit 5...
The speed ratio between the impression cylinder 8 and the blanket cylinder 7 can be adjusted. Note that when the adjustment motor 32 stops rotating, the differential gear 20 is turned on and off.
The output speed ratio is R:(R+1). R is the reduction ratio of the differential gear 20.

In this way, the rotational speed of the impression cylinder 8, that is, the paper feeding speed, can be freely adjusted by the differential device 20, so if the paper thickness is thicker than the standard value, the rotation of the impression cylinder 8 is reduced and the paper feed speed is adjusted. The printing pitch can be kept constant by lowering the feed speed and adjusting it conversely when the paper is thin. For this reason, printing may become unclear due to mismatch between the rotational speed of the blanket cylinder 7 and the paper feeding speed, and large tension may be applied between the printing section 2 and the paper feeding section 1 or the processing section 3 due to fluctuations in the printing pitch. This can be reliably prevented from happening. Furthermore, even if there is a difference in paper feeding speed between the printing units 5 due to variations in impression cylinder diameter, etc., by adjusting the paper feeding speed of one or both units as described above, It is possible to prevent the generation of large tension between units.

Other Embodiments () Another example of the configuration of the differential gear 20 is shown in FIG. In the above embodiment, the adjustment shaft 30 is rotationally driven by another drive source called the variable speed adjustment motor 32, but in this embodiment,
A gear type or other transmission 33 whose transmission ratio can be adjusted by manual operation to control the rotational force of the blanket body 7
, and its output is transmitted to the adjustment shaft 30 as a driving force via the belt transmission mechanism 34.

() The speed change means for adjusting the rotational speed of the impression cylinder 8 is not limited to the above-mentioned differential device 20.
A general gear type, belt type, etc. transmission may be used. However, the differential device 2 shown in the above embodiment
0 has the advantage of being able to perform fine speed adjustment with high precision.

Further, the present invention is not limited to multicolor printing presses, but can also be applied to monochrome printing presses having one printing unit. In this case, it is possible to prevent deterioration in printing accuracy due to changes in paper thickness in the printing unit and to prevent generation of large tension between the printing unit and the paper feed section 1 or the processing section 3.

(Effects of the Invention) As described above, according to the present invention, the rotation of the blanket cylinder in the printing unit of the printing section is transmitted to the impression cylinder through a speed change means such as a differential device, and the speed change means causes the impression cylinder to rotate. Since the rotational speed of the printer is configured so that the paper feed speed can be adjusted, the paper feed speed can be adjusted in accordance with changes in paper thickness, variations in impression cylinder diameter between printing units in a multicolor printing machine, etc. By doing this, the printing pitch can always be kept at the appropriate level.
In addition to improving printing accuracy, it also prevents the generation of large tension between the printing section and the paper feeding section or processing section, or between each printing unit in a multicolor printing machine,
This can contribute to extending the life of the paper feeding mechanism of each part.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an outline of a paper feed adjustment device according to an embodiment of the present invention, Fig. 2 is a side view showing a specific configuration of the device, and Fig. 3 is a sectional view of a differential device as a speed change means. , FIG. 4 is a diagram for explaining the same operating principle, and FIG. 5 is a second diagram showing another configuration example of the differential device.
Figure 6 is a diagram equivalent to Figure 1 showing the prior art, Figure 7 is a diagram equivalent to Figure 2 showing the drive system of the printing unit in the prior art, Figure 8 is a partially enlarged front view of the same, Figure 9 The figure shows the overall configuration of a foam printing machine. 2... Printing section, 5... Printing unit, 6... Plate cylinder, 7... Blanket cylinder, 8... Impression cylinder, 6a,
7a, 8a... Rotating shaft, 20... Differential device as a speed change means, 14, 15, 21, 22... Gears as a power transmission means.

Claims (1)

[Claims] 1. A printing unit of the printing section is composed of a plate cylinder, a blanket cylinder, and an impression cylinder, and each cylinder has the following functions:
In a form printing machine configured to sequentially transmit rotational force from the same drive source through rotational force transmission means provided on each rotational shaft, the rotational force transmission means of the blanket cylinder and the impression cylinder Paper feeding in a printing section of a form printing press, characterized in that a speed change means for changing the rotational speed of the impression cylinder independently of the plate cylinder and the blanket cylinder is provided between the rotational force transmission means and the rotational force transmission means. Regulator.