JPH0345808Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a plate cylinder for a multicolor sheet-fed printing press.

(Prior Art) The plate cylinder of a conventional multicolor sheet-fed printing press will be explained with reference to FIGS. 3 to 6. In FIG. , 03 is the second color printing unit, 04 is the paper discharge section, and 05 and 06 are the above printing units 02 and 03.
The printing cylinders 07 and 08 are the printing units 02 and 08, respectively.
03 is the blanket cylinder, 09 and 010 are the impression cylinders of the printing units 02 and 03, and 011 is the intermediate cylinder disposed between the printing unit 02 for the first color and the printing unit 03 for the second color. The printing paper (one sheet of printing paper) from section 01 is sent to the first color printing unit 02, where the ink is transferred from the plate cylinder 05 to the printing paper via the blanket cylinder 07, and the first color is printed. The ink is then sent to the second color printing unit 03, where the ink is transferred from the plate cylinder 06 to the blanket cylinder 0.
8, the image is transferred to printing paper, and the second color is printed. Note that the impression cylinders 09, 010 press the printing paper against the blanket cylinders 07, 08 during the above-mentioned printing, and the intermediate cylinders 011
functions to transfer the printing paper from the first color printing unit 02 to the second color printing unit 03.

Further, in FIG. 4 showing details of the plate cylinders 05, 06, 012 indicates a recess provided on the outer circumferential surface of the plate cylinders 05, 06, 013 indicates a plate attached to the outer circumferential surface of the plate cylinders 05, 06, 014 is a plate fixing device on the binding side, and 015 is a plate fixing device on the paper tail side. Each of the plate fixing devices 014 and 015 is slidably mounted on the recess 012. In addition, in FIG. 6 showing the details of the plate fixing device 015, 018a is the lower tooth at both ends, 018b is the lower tooth at the middle part, 017 is the plate tension bolt, 021 is the shaft, and 021a is the coaxial screw at the end of 021. , 022 is a bolt for moving the entire plate fixing device 015, and 023 is a plate fixing device 0.
End moving bolt for moving the end of 15, 024
025 is a screw, and 025 is a hole of the end moving bolt 023. When moving the plate fixing device 015 in the axial direction, the entire moving bolt 022 is rotated to move the plate fixing device 015 in the axial direction. When moving the end of the plate fixing device 015 in the axial direction, a pin or the like is inserted into the hole 025 of the end moving bolt 023 and the pin is rotated. At this time, since the shaft 021 is fixed, the end movement bolt 023 moves along the shaft 021, and as it moves, the lower teeth 018a at both ends of the plate cylinder align with the pitch of the screw 021a at the end of the shaft 021. It is guided by the shaft 021 and moves in the axial direction by the difference from the pitch of the screw 024. In other words, the plate fixing device 015 on the bottom side of the plate 013
The entire fixing device can be moved in the axial direction of the plate cylinder, and both ends of the fixing device can be moved in the axial direction of the plate cylinder.

During printing work, in order to print the first color pattern and second color pattern accurately without any confusion,
Even if the plate fixing device is moved and adjusted in the axial direction and circumferential direction of the plate cylinder, during actual printing, the first and second colors
Since the amount of elongation of the printing paper differs depending on the color, it is necessary to correct this. In Figure 5, if the amount of expansion of the printing paper in the printing direction is b and the amount of expansion in the width direction is a, then the amount of expansion in the width direction a for the first color increases as printing progresses, so the pattern of the second color is In order to match the pattern of the first color, it is sufficient to stretch the paper tail side of the plate 013 of the printing cylinder 06 of the printing unit 03 of the second color by the stretching amount ab in front. The amount of expansion b in the printing direction is corrected by strongly pulling the plate tension bolt 017 of the plate fixing device 015 on the paper tail side, and the amount of expansion a in the width direction is corrected by fixing the plate on the paper tail side. This is done by spreading both ends of the device 015 outward. Also, these extension amounts a, b
The correction is made to gradually increase toward the paper tail side, but the correction of the amount of extension b by the bolt 017 cannot be performed all around the circumference due to the frictional resistance between the plate 013 and the plate cylinder 06. Therefore, the shaded area in FIG. 5 remains as an area that cannot be corrected. Similarly, regarding the correction of the extension amount a, since the entire length of the lower tooth 018a at both ends is corrected in a stepwise manner, the shaded portion remains as an area that cannot be corrected. Incidentally, the amount of expansion a in the width direction is called fan-out.

(Problems to be solved by the invention) In the plate cylinder of the conventional multi-color sheet-fed printing press shown in FIGS. 1 to 6, () the multi-color sheet-fed printing press is stopped and Since it is necessary to adjust the amount of extension a, the operating rate of the multicolor sheet-fed printing press decreases. () Furthermore, the adjustment of the amount of extension a in the width direction of the plate cylinder requires experience on the part of the operator, and variations in adjustment are likely to occur. () Furthermore, there was a problem in that areas that could not be corrected remained on the lower teeth 018a at both ends of the plate fixing device 015 on the paper tail side.

(Means for Solving the Problems) The present invention addresses the above-mentioned problems by providing a plurality of holes along the circumference inside the plate cylinder, from the gripping side of the plate cylinder to the bottom side of the plate. Multicolor printing characterized in that a plurality of electrical resistance heating elements with different heat generating capacities are installed in each of the holes so that the heat generating capacity increases sequentially in accordance with the amount of stretching of the printing paper in the width direction, which increases as the printing paper approaches the width direction. The present invention relates to the plate cylinder of a sheet-fed printing press, and its purpose is to improve the operating rate of a multi-color sheet-fed printing press. No skill is required to adjust the amount of extension of the plate cylinder in the width direction. Another object of the present invention is to provide an improved plate cylinder for a multi-color sheet-fed printing press that can eliminate the uncorrected area on the lower teeth at both ends of the plate fixing device on the paper tail side.

(Function) The plate cylinder of the multi-color sheet-fed printing press of the present invention is constructed as described above, and each electric resistance heating element heats and thermally expands the plate attached to the surface of the plate cylinder, so that the plate is heated. The printing paper is stretched to correspond to the widthwise stretching amount of the printing paper, which increases from the gripping side to the bottom side of the plate.

(Embodiment) Next, the multi-color sheet-fed printing press of the present invention will be explained using an embodiment shown in FIGS. 1 and 2. R ₁ , R ₂ , R ₃ ,
R ₄ , R ₅ , and R ₆ are a plurality of electric heating resistors with different heat generating capacities; 26 is a plurality of holes provided along the circumference inside the plate cylinder 6; and 27 is a shaft supporting the plate cylinder 6. ,
Reference numeral 28 denotes an electric wire, and 29 a current collecting ring, each of which is connected to each of the above-mentioned electric wires so that the heat generating capacity increases sequentially in response to the amount of expansion in the width direction of the printing paper, which increases from the gripping side of the plate cylinder 6 toward the bottom side of the plate. Heat generating resistors R ₁ to _{R 6} are installed in each of the holes 26 . Also, each electric heating resistor R ₁ R ₂
~ _R6 is connected to the current collection ring 29 via the electric wire 28,
Collecting ring 29 from the power supply source outside the multicolor sheet-fed printing machine
Electric power is supplied to each of the electric heating resistors R ₁ to _{R 6} through the electric wires 28 and 28 . The heat generating capacity of each of the electrical heating resistors R ₁ to _{R 6} is such that R ₁ <R ₂ <R ₃ <R ₄ <R ₅ <R ₆ from the gripping side to the print bottom side. The heat generating capacity of each of the electric heating resistors R ₁ to _{R 6} is determined by subtracting the planned temperature from the heat loss obtained based on the wall thickness of the plate cylinder 6 and other dimensions.

Next, the operation of the plate cylinder 6 shown in FIGS. 1 and 2 will be explained in detail. Each electric heating resistor is connected from a power supply source outside the multicolor sheet-fed printing machine via a current collector ring 29 and an electric wire 28.
Power is supplied to R ₁ to _{R 6} , and each electric heating resistor R ₁ to _{R 6} generates heat, and the aluminum plate 13 attached to the surface of the plate cylinder 6 is heated and thermally expanded, causing the same plate to heat up. 13 expands to correspond to the amount of expansion of the printing paper in the width direction, which increases from the gripping side of the plate cylinder 6 toward the bottom side of the plate.

(Effects of the invention) The plate cylinder of the multicolor sheet-fed printing press of the present invention is constructed as described above, and each electric resistance heating element heats and thermally expands the plate attached to the surface of the plate cylinder. The printing paper is stretched to correspond to the widthwise stretching of the printing paper, which increases from the gripping side of the plate cylinder to the plate bottom side, so the multicolor sheet-fed printing press is stopped and the printing paper is stretched in the widthwise direction. There is no need to correct this, and the operating rate of multicolor sheet-fed printing presses can be improved. Further, since the correction is automatically made as described above, no skill is required to adjust the amount of extension of the plate cylinder in the width direction. Further, since the correction is performed as described above, it is possible to eliminate the uncorrected area that is located at the lower teeth at both ends of the plate fixing device on the paper tail side. 4

[Brief explanation of the drawing]

FIG. 1 is a longitudinal side view showing an embodiment of the plate cylinder of a multicolor sheet-fed printing press according to the present invention, FIG. 2 is a longitudinal front view thereof, and FIG. 3 is a side view showing a conventional multicolor sheet-fed printing press. , FIG. 4 is an enlarged side view of the plate cylinder, FIG. 5 is an explanatory view showing the amount of expansion of the printing paper in the width direction, and FIG. 6 is a perspective view showing the plate fixing device on the plate bottom side. 6... Plate cylinder, 26... Hole, _R1 to _R6 ... Electric resistance heating element, a... Amount of extension of printing paper in the width direction.

Claims (1)

[Scope of utility model registration request] A plurality of holes are provided inside the plate cylinder along the circumference, and the heat generating capacity increases sequentially in response to the widthwise expansion of the printing paper, which increases from the gripping side of the plate cylinder to the bottom side of the plate. A plate cylinder for a multicolor sheet-fed printing press, characterized in that a plurality of electrical resistance heating elements having different heat generation capacities are installed in each of the holes.