JPS58118256A - Blanket drum for offset drum - Google Patents

Abstract

PURPOSE:To provide a blanket drum of an offset printer which facilitates exchanging of a blanket, by a method wherein a magnets placed to the blanket drum of the offset printer, and an iron plate, whereto the blanket is adhered, is secured by the magnets. CONSTITUTION:Magnets 3 are secured to an inner peripheral surface of a blanket drum 1, a blanket 5 is adhered to a heat sheet 7 through the medium of an adhesive agent, and the iron sheet 7, wound around the outer periphery of the blanket drum 1, is magnetically fastened by the magnets 3 mounted to the inner peripheral surface of the blanket drum 1. Usually, a plate whereto a plate is attached and a blanket drum whereto a blanket is attached are adapted to have a periphery equal to each other. The total thickness of the blanket 5 and the iron sheet 7 is thicker than that of the plate, and thereby the diameter of the blanket drum 1 is set to a size smaller than that of a plate drum or a press drum.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blanket cylinder for an offset printing press, and more particularly to a blanket cylinder for an offset printing press that allows easy replacement of the blanket.

The printing unit of an offset printing press basically consists of a plate cylinder, a blanket cylinder, and an impression cylinder, and a blanket is detachably attached to the blanket cylinder. Usually, the blanket is fixed mechanically by gripping both ends of the blanket.

This is because the blanket becomes worn or damaged, and it is necessary to replace the plate from time to time to obtain consistent print quality. Also, the blanket needs to be replaced when the printing paper is changed. However, in conventional offset printing machines, the blanket is mechanically gripped or sandwiched, which requires tightening multiple bolts in the axial direction of the blanket cylinder, making it time consuming to replace the blanket. There was a problem.

Therefore, the present invention solves the above problems.

An object of the present invention is to provide a blanket cylinder for an offset printing press that allows easy replacement of the blanket.

That is, the gist of the present invention is a blanket cylinder for an offset printing press, in which a magnet is attached to the pre-socket cylinder, and an iron plate to which the blanket is attached is fixed by the magnet.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a cross section of the blanket cylinder (1), and a magnet (3) is fixed to the inner peripheral surface of the blanket cylinder +11. Further, as shown in the second figure, the blanket (5) is attached to the iron plate (7) via adhesive ',5, and the third
As shown in the small figure, a magnet (3
) to magnetically fix the iron plate (7). Usually, the plate cylinder and planke after plate mounting and blanket mounting.

The torso has the same circumference.

Furthermore, since the combined thickness of the blanket (5) and iron plate (7) according to the present invention is thicker than that of the plate, the diameter of the blanket cylinder (1) is made smaller than that of the plate cylinder and the impression cylinder.

Dad, on Blanket Cylinder +11, I have shown where to fix the ends of the blanket. Set up a landmark (not shown)
, always attach the blanket in the same position.

For the 1st plate cylinder, this is the part that holds the plate, on the other hand,
This is because each blanket cylinder has a portion that cannot be printed, such as the edge of the blanket, and the plate cylinder and blanket cylinder are interlocked, so that the portions that cannot be printed (+111) must always match.

Incidentally, the number of magnets (3) and their mounting positions are not limited to the example of the L actual gun, but may be in any manner as long as the PLAN 7 can be fixed.

Further, the magnet (3) may be a permanent magnet or an electromagnet.

When the magnetism of the magnet (3) is strong, it is possible to fix the blanket to the blanket cylinder configured as described above. , a groove CI+1 is provided, while a fifth groove CI+1 is provided.
0 of the iron plate α row with the plunget (5) attached as shown.
Insert the locking part (11) of 3, and then insert the blanket cylinder (9).
By wrapping the blanket around the blanket and fixing it with a magnet (3), printing can be performed without the blanket shifting. Furthermore.

In order to ensure the fixation of the iron plate and blanket cylinder, step 7
As shown in the figure, a protrusion 0η is formed on the inner side of the groove θυ provided in the blanket cylinder (9), and on the other hand, a locking portion 0!9 of the iron plate 0 is formed.
In this case, a locking hole α Yu may be bored and the locking hole Gel may be fitted into the projection OD.

As described below, the blanket cylinder of the present invention has a simple structure in which a magnet is attached to the inner circumferential surface, and in order to attach the blanket, it is sufficient to simply wrap the iron plate to which the blanket is attached around the blanket cylinder. On the other hand, to remove the blanket, all you have to do is peel off the iron plate to which the blanket is attached, so you can replace the blanket in a very short time.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and Fig. 1 is a cross-sectional view of a blanket cylinder, Fig. 2 is a perspective view showing an iron plate with plungets attached, and Fig. 3 is a blanket attached to the blanket cylinder. Figures 4 to 6 are diagrams showing other embodiments. Figure 4 is a sectional view of the blanket cylinder, Figure 5 is a perspective view of the iron plate to which the blanket is attached, and Figure 6 is a diagram showing the state. is plan 2. ) A diagram showing a state in which the blanket is attached to the cylinder, and FIG. 7 shows still another embodiment, and is a diagram showing a groove provided in the blanket cylinder. 1, 9...Blanket body 3...
・・・・・・・・・・・・Magnet 5 ・・・・・・・・・
・・・・・・Blanket 7.13・・・・・・・・・
・Iron plate 11 ...... Groove 15 ...... Locking part 17 ......
-...Protrusion 19...Locking hole Patent applicant
Dai Nippon Printing Co., Ltd. Patent Attorney Atsumi Konishi Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 5 Figure 6 Figure 7 = 28;

Claims (2)

[Claims] (1) A blanket cylinder for an offset printing press, characterized in that a magnet is attached to the blanket cylinder, and an iron plate to which the blanket is attached is fixed by the magnet. (2) A plancher for an offset printing press according to claim 1, wherein a groove is provided along the axial direction on the surface of the blanket cylinder for locking an iron plate to which a blanket is attached.