JPH06255085A - Blanket cylinder of offset press - Google Patents

Abstract

PURPOSE:To prevent the generation of a shock in a blanket cylinder and to enhance the rate of operation of a machine by absorbing the pressure venting generated by the loss of contact pressure when the grooves of two blanket cylinders rotated in mutually opposed relationship meet with each other by the perfect cylindrical surface part provided to the main body of the blanket cylinder in the surface length direction thereof. CONSTITUTION:When printing operation is performed, one metal fitting 8 of a blanket 1 is hooked with the jaw part 5 of a blanket cylinder main body 2 and the blanket 1 is wound around the outer diameter surface of the cylinder main body 2 to insert the metal fitting 9 provided to the other end of the blanket in the groove of a winding shaft through the slit groove 3 of the cylinder main body 2 and the shank of the winding shaft is rotated to tighten the blanket 1 to wind the same around the cylinder main body. At this time, a cantilevered tongue part is fitted in a notch part 18 to be connected thereto by a fishing hook-shaped projection 20 having a barb and a blanket cylinder having a perfectly smooth cylindrical surface part provided to a part of the cylinder surface length thereof is formed. Therefore, even when a pair of blanket cylinders come into contact with each other under pressure in x mutually opposed relationship during operation and the blanket involving grooves thereof meet with each other, the blanket cylinders can t>e smoothly and continuously rotated y the cylindrical surface part and pressure venting suddenly eliminating contact pressure is reduced and a shock can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blanket cylinder of an offset printing machine in which the ink is directly transferred by rolling on paper during printing.

[0002]

2. Description of the Related Art A blanket cylinder of a conventional offset printing machine is shown in FIG.
And FIG. 10 demonstrates. In offset printing machines,
Two blanket cylinders 39 are arranged so as to face each other, and both sides of the paper running between them are pressed to perform double-sided printing at the same time. This blanket 3
9 includes a blanket cylinder body 31 and a sheet-shaped blanket 34. Grooves 32 are provided over the entire width of the outer circumferential surface of the blanket cylinder body 31 along the axial direction.
The sheet metal blanket 34 to which the metal fittings 35 and 36 as shown in FIG. 0 are attached is inserted into the metal fitting 35 side at one end, the blanket 34 is wound around the outer periphery of the blanket cylinder body 31, and the other metal fitting 36 side is fitted into the groove 32. Have been inserted into. Further, each of the metal fittings 35 and 36 at both ends thereof is rotatably attached to the lower side of the groove 32 inside the body of the blanket cylinder body 31.
It is configured such that it is inserted into the slits 43 and 44 of the Nos. 1 and 42, wound, pulled, and wound and fixed. In the printing machine, the rotation of the blanket cylinder 39 is used within a range of 0 to 1000 rpm, and the blanket cylinder 39 is formed with the blanket 34 wound around it. (Hereinafter referred to as gap) 37 comrades will meet each rotation. For this reason, the printing pressure between the two blanket cylinders 39 fluctuates once per rotation, which causes a shock and gives a shock mark to the printing surface, degrading the printing quality. Therefore, as a preventive measure against the fluctuation of the printing pressure, the gap 37 is fixed over the entire length or in part by embedding a metal filling 38. The embedded metal 38 is inserted into the gap 37 and fixed with bolts 40, and the upper surface of the embedded metal 38 is integrated with the outer peripheral surface of the blanket cylinder 39 in which the blanket 34 is wound around the outer periphery of the blanket cylinder body 31. It is formed so as to form a perfect cylindrical surface. In this way, the two blanket cylinders 39 are arranged so as to face each other, and shock marks are not generated when two-sided printing is performed simultaneously by rolling on both sides of the paper running between them.

[0003]

However, in the above-described shock prevention measures for covering the gap of the blanket cylinder with a metal burial, the blanket thickness is subtly different depending on each maker or brand, and at the same time the printed matter is simultaneously printed. The outer diameter of the blanket cylinder is slightly different due to the different selection of the underpack that is laid between the blanket and the blanket cylinder body depending on the conditions such as the type and the printing operator. Because the blanket is liable to change its thickness due to the operation of the machine, the burial configured in this way cannot cope with these subtle differences in thickness and changes, and shock cannot be prevented. Due to repeated mounting and removal of gold, the mounting surfaces of the embedded metal and the blanket are dented, resulting in an error in the height accuracy of the embedded metal, and shock cannot be effectively absorbed.
In addition, when exchanging the blanket, which is a consumable item, it is necessary to attach and detach the padding, which is a waste of time and reduces the operating rate of the machine.
An object of the present invention is to provide a blanket cylinder that can prevent a shock from occurring in the blanket cylinder of a conventional offset printing machine and improve the operating rate of the machine.

[0004]

In order to achieve the above object, a blanket cylinder of an offset printing machine according to the present invention is provided with a groove in an axial direction of a cylindrical surface, and both ends of a sheet-shaped blanket are inserted into the groove, In a blanket cylinder of an offset printing machine in which a blanket is wound around the outer periphery, a blanket cylinder body has a complete cylindrical surface at one axial position, and the remaining cylinder surface is axially discontinuous with the cylindrical surface portion. And the blanket cylinder body provided with a slit-like groove, the metal fittings attached to the widthwise direction of the sheet-shaped blanket from which the portions corresponding to the cylindrical surface portion have been removed respectively, and the metal fittings on one end that have been removed. It has a cutout in a direction perpendicular to the metal fitting, and has a hook-like protrusion on the other end of the removed metal fitting that is fitted with the cutout and has a barb when wound around the main body of the blanket cylinder. Sheet blanket with cantilevered tongue And a rubber cylinder of an offset printing machine comprising a and. Further, the metal fittings at both ends of the sheet-like blanket are integrated without a removing portion, and the discontinuous portion of the slit-like groove of the blanket body is composed of a detachable component. A blanket cylinder of a printing press, wherein a plurality of constituent elements, which are provided on the outer surface of the blanket cylinder body and form a complete cylindrical surface, are provided at arbitrary positions in the surface length direction. And

[0005]

According to the present invention, when the grooves of two blanket cylinders that rotate relative to each other meet each other, the pressure drop that occurs when the contact pressure disappears is a complete cylindrical surface portion provided locally in the longitudinal direction of the blanket cylinder body surface. It is absorbed by and is prevented from generating a shock.

[0006]

Embodiments of the present invention will be described below with reference to FIGS. In the following description, the same components as those in the above-described conventional example will be denoted by the same reference numerals, description thereof will be omitted, and only newly added members will be described. As shown in FIG. 2, a slit groove 3 is provided in the surface length direction of the blanket cylinder body 2 for winding and fixing the blanket 1 on the blanket cylinder body 2. A part of this slit groove 3 is interrupted and the blanket cylinder main body 2
The bridge portion 25 that completely forms a cylindrical surface portion together with the outer diameter surface 4 is provided at one place. On the other hand, as shown in FIG. 3, the sheet-shaped blanket 1 wound around the blanket cylinder body 2 and fitted around the blanket body 2 has metal fittings 8 and 9 at both ends over the entire width. When the blanket 1 is wound and wrapped around the blanket cylinder body 2, the parts 10 and 11 of the metal fittings 8 and 9 at both ends that match the bridge portion 25 are removed, and the metal fitting removing portion 10 near the one end is removed. A part of the rubber blanket 7 is provided with a notch 18 in a direction perpendicular to the metal fitting 8, and at the same time, the rubber blanket 7 near the metal fitting removing portion 11 of the metal fitting 9 at the other end is provided with protrusions 20 on both sides. Have nineteen. When the printing operation is performed, one metal fitting 18 of the blanket 1 is hooked on the jaw portion 5 of the blanket cylinder main body 2 and wound around the outer diameter surface of the blanket cylinder main body 2, and the other metal fitting 9 is attached to the blanket cylinder main body 2. Slit groove 3
Through the groove 15 of the winding shaft 6, and the shank 17 of the winding shaft 6 is rotated to tighten the blanket 1 to wind it around. At this time, the cantilevered tongue portion 19 is fitted into the notch portion 18 and is joined by a barbed needle-like projection 20 which forms a blanket cylinder 1 having a completely smooth cylindrical surface portion in a part of the body surface length. . It should be noted that the present invention is not limited to the above-described embodiments, and improvements, modifications and the like within the scope of achieving the present invention are included in the present invention. In the above embodiment, the blanket cylinder body 2 has the bridge portion 25 forming the cylindrical surface portion integrated with the blanket cylinder body 2. However, as shown in FIGS. It is also possible to separate the main body 12 into a separate padding 13 and attach and detach it with a bolt 14. In this case, it is not necessary to remove the metal fittings at both ends of the blanket as described above, and the blanket 16 using the integrated metal fittings 23 and 24 as shown in FIG. 7 can be used. After the blanket 16 is wound around the blanket cylinder body 12 and wound around it, the padding 13 may be fixed to the blanket cylinder body 12 with the mounting bolts 14. In the above description, the case where the number of the winding shaft 6 is one is shown in FIG.
The same applies when the winding shafts 21 and 22 are used.
As a result, even if the blanket winding grooves of the pair of blanket cylinders that face each other and rotate while being pressed against each other are encountered during the operation of the machine, the cylindrical surface portions allow smooth and continuous rotation. In the above-described embodiment, the case where the bridge portion 25 is provided at one place has been described. However, the number of the bridge portions is not limited to this, and the blanket can be provided by providing notches and tongues in the blanket in a corresponding number. More easily adheres to the body surface.

[0007]

According to the present invention, a part of the blanket rolling slit groove provided along the length of the blanket cylinder surface is interrupted, and a complete cylindrical surface portion is formed at a part of the length of the blanket cylinder surface. There is an effect that it is possible to provide a blanket cylinder that can prevent the occurrence of shock by reducing the pressure loss when the contact pressure due to the two blanket cylinder grooves facing each other during the machine operation is suddenly lost.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

FIG. 2 is a blanket cylinder body of the present invention.

FIG. 3 is a blanket of this embodiment.

FIG. 4 is a detailed view of a cantilevered tongue portion of the rubber blanket of this embodiment.

FIG. 5 is an explanatory view of another embodiment in which the bridge portion of the blanket cylinder body of FIG.

6 is a detailed view of the burying metal of FIG.

FIG. 7 shows an example in which both bracket metal fittings are not broken due to a modification of the present invention.

FIG. 8 is an example of a blanket cylinder having two rubber winding shafts.

FIG. 9 is an explanatory view of a conventional blanket cylinder.

FIG. 10 is an explanatory diagram of a conventional blanket.

[Explanation of symbols]

 1 blanket 2 rubber body 3 slit groove 4 outer diameter surface 6 winding shaft 25 bridge part

Claims (3)

[Claims] 1. A blanket cylinder of an offset printing machine in which a groove is provided in an axial direction of a cylindrical surface, both ends of a sheet-shaped blanket are inserted into the groove, and the blanket is wound around the outer periphery, in the axial direction of the main body of the blanket cylinder. Has a complete cylindrical surface in one place, and the remaining barrel surface is a blanket cylinder body provided with slit-shaped grooves that discontinue the cylindrical surface portion in the axial direction, and both ends correspond to the cylindrical surface portion. The metal fittings attached in the width direction of the sheet-shaped blanket from which the brackets have been removed have a notch in the direction perpendicular to the metal fittings at the part where the metal fittings at one end have been removed, and the rubber part where the metal fittings at the other end have been removed A blanket cylinder of an offset printing machine, comprising: a sheet-like blanket having a cantilevered tongue portion having a barb-like projection with a barb on the periphery that fits in the notch when wound around the body. . 2. The metal fittings at both ends of the sheet-shaped blanket according to claim 1, wherein the metal fittings are integral with each other without a removal portion,
The blanket cylinder of an offset printing press, wherein the discontinuous portion of the slit-shaped groove of the blanket cylinder body is composed of components that can be attached and detached. 3. The blanket cylinder of an offset printing machine according to claim 1, wherein a plurality of constituent elements provided on the outer surface of the blanket cylinder main body and forming a complete cylindrical surface are provided at arbitrary positions in the longitudinal direction. .