JP3614581B2 - Blanket for printing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a blanket for offset printing used in an offset printing machine.
[0002]
[Prior art]
A rubber blanket used for offset printing generally has a sponge rubber layer (compressible layer) and a surface rubber layer on a reinforcing substrate. The reinforcing base is usually a plurality of base fabrics, usually 3 to 4 base fabrics, fixed with an adhesive to prevent the blanket from extending when the blanket is attached to the blanket cylinder of the printing press. The strength of the blanket is increased so that it can withstand an impact, thereby extending the life of the blanket.
[0003]
As a method of mounting such a blanket on the blanket cylinder, there is a method using a so-called tension bar. That is, the blanket is inserted into an alligator-shaped insertion bar so as to wrap both ends of the blanket, the other blanket cylinder has a gap and a recess is opened, and a tension bar provided with a notch groove is built in. A notch groove is provided in the side wall of the recess of the blanket cylinder. Then, after inserting one insertion bar (the end of the bottom end of the blanket) into the notch groove of this blanket cylinder and winding the blanket while pulling around the blanket cylinder, the other insertion bar (the end of the holding side end) ) And tighten. However, in this method, since the insertion bar is relatively thick, the blanket cylinder gap increases accordingly, the blanket part not involved in printing increases, and the plate cylinder or impression cylinder contacts the blanket part corresponding to the gap. There was a disadvantage that the impact at the time was large, and it was difficult to improve the printing speed.
[0004]
Therefore, in recent years, a so-called narrow gap method in which the gap is narrowed has been adopted in order to reduce the impact and improve the printing speed (Japanese Patent Laid-Open No. 7-285214). In this method, for example, instead of the insertion bar, a thin strip is fixed to each end of the blanket with an adhesive, and one end (the end on the side of the grip) is inserted into the gap of the blanket cylinder. In this unconstrained state, the tension bar is half-turned and the blanket is wound around the blanket cylinder, and then the other end (the end on the side of the grip) is inserted into the gap and tightened, thereby strengthening the blanket. It is a method of wearing. According to this method, since the band plate fixed to the end of the blanket is relatively thin, the gap provided in the blanket cylinder can be narrowed accordingly, the size of the blanket part not involved in printing is reduced, and the impact is reduced. And can improve the printing speed.
[0005]
[Problems to be solved by the invention]
However, the conventional insertion bar grips the blanket so that it wraps around the end of the blanket, whereas the strip used in the narrow gap method is simply fixed to the back of the end of the blanket base. Therefore, the problem that it was easy to peel off especially at the end of the end of the blanket with a narrow strip width was revealed. For example, among a plurality of base fabrics constituting the base material of the blanket, stress due to impact acts between the base fabric on the side in contact with the band plate and the base fabric on the base fabric, and the blanket is peeled between the base fabrics. . Moreover, if the adhesive force between these base fabrics is strengthened, peeling will occur between the base fabrics further above. Note that it is almost impossible to reinforce the compressible layer because the function as the compressible layer is lost.
[0006]
Accordingly, an object of the present invention is to improve the blanket life by suppressing peeling of the end region by a relatively simple means in a printing blanket having a band plate in such an end region. .
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention provides a width of 12 mm to the other surface of the base material in the end region of the blanket body provided with a compressible layer and a rubber layer as the uppermost layer on one surface of the base material. A printing blanket provided with a 20 mm band plate, wherein the blanket body is made of nylon or vinylon in the width direction of the blanket body in an end region of a planned portion located at least on the bottom end of the band plate. A blanket for printing is provided, which is stitched with a thread having a thickness of No. 100 to No. 100 .
The number of yarns is usually 1 to 3, and when using a plurality of yarns, it is preferable to sew them apart from each other.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view showing a blanket according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view (enlarged) taken along line II-II in FIG. As shown in these figures (particularly FIG. 2), this blanket 10 has the same structure as a normal blanket except for stitching with a thread, which will be described in detail later, and a plurality of (three in FIG. 2) base fabrics. The substrate 13 is formed by adhering 11a, 11b and 11c with adhesives 12a and 12b made of, for example, acrylonitrile butadiene rubber (NBR). A compressible layer 14 made of sponge rubber is formed on the base material 13, and a reinforcing cloth 15 is provided thereon. On the reinforcing cloth 15, a rubber layer 17 is provided as an uppermost layer via an adhesive 16. In the blanket body having such a configuration, a thin strip 18 made of, for example, steel is fixed to the rear surface of the end region of the base material 13 by an adhesive 19. The strip 18 has a thickness of 0.5 mm to 0.7 mm and a width of 12 mm to 20 mm, for example. Although only one end of the blanket is shown in FIGS. 1 and 2, a band plate is similarly provided at the other end of the blanket.
[0009]
Now, in the end region of the blanket body to which the band plate 18 is fixed, the blanket body passes through the base material 13, the compressible layer 14, the reinforcing cloth 15, the rubber layer 17 and the like in the width direction and is sewn with a thread. ing. 1 and 2 show an example in which the two threads 20 and 21 are sewn apart as the most preferable embodiment, but the number of threads is determined according to the width of the end region (band 18). Can be changed. Usually, sewing can be done with 1 to 3 threads. These yarns are prevented from falling off by an adhesive 19 that fixes the band plate 18 to the back surface of the base material. The thread has sufficient strength to sew the blanket body and has a thickness that does not hinder the bonding of the band plate 18 to the back surface of the base material 13. More specifically, the thickness of the yarn is preferably about 20 to 100, and more preferably about 60, although it depends on the material. Cotton, vinylon, nylon, polyester, etc. can be used as the material of the yarn, but in order to satisfy both the predetermined strength and the adhesiveness with the strip within the above thickness range, vinylon and nylon are particularly preferable. preferable. The stitch width and stitch pitch are not particularly limited, but the stitch width is usually 2 to 4 mm.
[0010]
Such a blanket can be manufactured by a conventional method. For example, the sponge rubber layer 14 is placed on the base fabrics 11a to 11c coated with an adhesive (for example, NBR) constituting the adhesive layers 12a and 12b, and the adhesive layer 16 is placed thereon. The reinforcing cloth 15 to which the constituent adhesive (for example, NBR) is applied is placed. Finally, after the surface rubber layer 17 is placed, this laminate is pressurized and integrated under heating to obtain a blanket body. Thereafter, according to the present invention, the end of the blanket body is stitched with the threads 20 and 21, and finally the band plate 18 is fixed with an adhesive 19 (for example, epoxy resin, urethane rubber or the like).
[0011]
FIG. 3 is a schematic cross-sectional view showing the blanket 10 of the present invention mounted on the blanket cylinder 31. A tension bar hole 32 is formed in the blanket cylinder 31, and a tension bar 33 is incorporated therein. A cutout groove 34 is formed in the tension bar 33. In order to attach the blanket 10 to the blanket cylinder 31, first, an end portion (end portion on the side of the bottom end) sewn with a blanket thread is inserted from the gap 35 until the band plate 18 has completely entered the hole 32. Next, the blanket cylinder 31 is wound around the blanket cylinder 31 while rotating the blanket cylinder 31 once. At this time, since the upper end of the strip 18 contacts the end of the gap 35 and the tip of the blanket 10 contacts the outer peripheral surface of the tension bar 33, the blanket 10 does not escape due to frictional resistance. When the notch groove 34 comes to a position facing the gap 35 by one rotation of the blanket cylinder 31, the other end of the blanket 10 (the end portion on the side of the gripper here also has a strip 18 'similar to the strip 18 on the back of the substrate). Is inserted into the notch groove 34 from the gap 35, and the tension bar 33 is rotated in the tightening direction indicated by the arrow A in the figure to firmly attach the blanket. Since the stress generated in the blanket 10 thus mounted is mainly applied to the end portion on the side of the bottom end of the narrow strip, in the present invention, the end portion on the side of the end portion of the blanket has been described with reference to FIGS. Suture with thread.
[0012]
【Example】
Hereinafter, the present invention will be described with reference to examples.
EXAMPLE A blanket having the same structure as that described with reference to FIGS. 1 and 2 was produced. Cotton cloth was used as the base cloths 11a to 11c and the reinforcing cloth 15, and these were bonded with an NBR adhesive. The thickness of the blanket body excluding the strip 18 was 1.9 mm, and the strip 18 was 0.7 mm thick and 12.7 mm wide. Both the yarns 20 and 21 were nylon yarns having a thickness of 60, and were sutured at positions of 3 mm and 6 mm from the end of the blanket, respectively. A band plate was also attached to the back of the other end of the blanket body, but this portion was not sewn with a thread. When this blanket was mounted on a blanket cylinder and installed in an offset printing machine, printing was performed. After printing 6 million copies, no peeling occurred in any part of the blanket. In addition, the intensity | strength between the base fabric 11b and the base fabric 11c was 2.6 kg / cm.
[0013]
A blanket similar to that of the above example was manufactured except that stitching with the comparative yarns 20 and 21 was not performed, and the same offset printing was performed. Phenomenon). When the blanket was examined, peeling was recognized between the base fabric 11a and the base fabric 11b. In addition, when each interlayer strength of this blanket was measured, 0.6 to 1.3 kg / cm between the reinforcing cloth 15 and the base cloth 11c, 0.9 to 1.5 kg / cm between the base cloth 11c and 11b, The distance between the fabrics 11b / 11a was 0.9 to 1.6 kg / cm.
[0014]
【The invention's effect】
As described above, according to the present invention, the delamination of the blanket can be suppressed and the life of the blanket can be improved by a relatively simple means such as stitching with a thread.
[Brief description of the drawings]
FIG. 1 is a plan view partially showing a blanket according to an embodiment of the present invention.
2 is a cross-sectional view taken along line II-II in FIG.
FIG. 3 is a schematic sectional view showing a blanket according to an embodiment of the present invention mounted on a blanket cylinder.
[Explanation of symbols]
11a, 11b, 11c ... base fabrics 12a, 12b ... adhesive layer 13 ... base material 14 ... compressible layer 17 ... surface rubber layer

Claims (2)

A blanket for printing in which a band plate having a width of 12 mm to 20 mm is provided on the other surface of the base material in the end region of the blanket body having a compressible layer and a rubber layer as the uppermost layer on one surface of the base material The blanket body is sutured with a thread of No. 20 to No. 100 made of nylon or vinylon in the width direction of the blanket body at least in the end region of the planned portion located on the side of the grip end where the band plate is provided. A blanket for printing. The printing blanket according to claim 1, wherein an end region of the blanket body is stitched by up to three threads.

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