JP4629115B2 - Corrugated stencil printing machine - Google Patents

Description

  The present invention relates to a corrugated board stencil printing machine that solves the problem that printing on corrugated board is difficult with a stencil printing machine.

  Conventionally, a rubber plate for corrugated cardboard printing is produced by corroding a metal plate to produce an original plate, from which a master mold such as plastic is manufactured, and then a rubber is poured into the master mold plate to pressurize it. It has been made by hand carving from vulcanized rubber sheets. However, in this case, since many steps are required, it takes too much cost and time, and since the accuracy of the obtained rubber plate itself is poor, there is a problem that a back-cutting is necessary for use. In order to solve this problem, a method for producing a corrugated board printing plate using a photosensitive elastomer composition has recently been proposed. So-called flexographic printing has become the mainstream of cardboard printing. For example, in a corrugated cardboard printing plate obtained by processing a composition containing a photosensitive elastomer composition that is solid at room temperature and its support in the order of image exposure, non-image area peeling and development, the support and What was provided with the adhesive layer between photosensitive elastomer compositions was developed (refer patent document 1).

  Flexographic printing uses a relief printing plate with rubber and resin with excellent rebound resilience. Adopts a method in which water-based ink is transferred to the convex part, which is the image part of the plate, and printed directly onto the corrugated cardboard sheet. is doing. This flexographic printing method is very suitable for mass production, and was developed and evolved in the age of mass consumption and mass production. However, the biggest drawback is that it is unsuitable for the small lot printing currently demanded by the market. That is, (b) it takes time to prepare a printing plate for corrugated cardboard, and (b) the plate price is high.

In the mass production era, the time required for plate making was not considered as a problem. Instead, the plate material is required to have a printing endurance capable of withstanding a large amount of printing, and as a result, the current plate has a high printing endurance performance of tens of thousands to millions. Even if the time required for current plate making is small, it takes 2 to 3 hours, and then 1 hour for the pasting process, 3 hours or more in total. In addition, plate making operations are mainly outsourced. And because the raw materials are expensive, the plate price is expensive. Corrugated cardboard cases are ordered and delivered as needed, so cardboard companies print and deliver cardboard cases only for the order quantity. The version to be used is kept on the assumption that there is a repeat. Every time a cardboard case is ordered, it is taken from the printing place to the printing site. For this reason, there is a large plate storage area for storing plates, and the plates are currently stored for a long period (years) as long as there is “the product” packed in cardboard. However, the plate deteriorates with time due to natural ultraviolet rays. For this reason, elasticity, rebound resilience, and the like are impaired due to the physical properties of the plate, the plate hardness changes, and a phenomenon of plate chipping and printing failure frequently occurs. Under the circumstances as described above, the plate making time, delivery, and plate making costs cannot be ignored in the era of small lots and various varieties in recent years.
JP-A-6-83044 (page 2)

  As described above, there are various problems in flexographic printing. If printing can be performed on corrugated board by stencil printing as an alternative method, the above problems can be solved. Stencil printing is widely used as an office press printer that can handle prints generated mainly in offices, schools, and stores. Although the method proposed this time is basically this method, even if the current state is adopted as it is, it is impossible to perform cardboard printing. The reason is that the surface of the corrugated cardboard itself is very uneven (average: 50 μm to 2 mm), and in the office press printer system on the market, the corrugated cardboard sheet and cardboard case are crushed, and satisfactory printing is achieved. Not only is it not possible to maintain the pressure strength of the cardboard itself, which is the original cardboard function. The cause is that, in the current system, as shown in FIG. 4, the heat sensitive stencil sheet (stencil sheet 3) is wound on a stainless steel cylinder (plate cylinder 1), so the printing pressure range during printing is very high. Narrow and smooth (5-15μ) like ordinary copy paper Even if the printing cylinder 4 applies excessive printing pressure, the printing result has no problem in the print quality and the copy paper itself, but to the corrugated cardboard 5 For this printing, it is impossible to print while maintaining the pressure strength, which is a cardboard function. Reference numeral 6 in FIG. 4 indicates ink. FIG. 5 shows a state in which the core of the cardboard 5 is completely crushed by excessive printing pressure, and the function of protecting the contents of the cardboard 5 is impaired.

  Therefore, the present invention provides a buffer layer in the middle of the cylinder heat-sensitive stencil sheet, so that even if the printing pressure range is greatly expanded, the corrugated cardboard is not crushed and excessive printing pressure is applied along the corrugated surface irregularities. In addition, an object of the present invention is to provide a corrugated stencil printing machine that can perform printing while following unevenness, and can print while maintaining the pressure strength of the corrugated board to the maximum without impairing the printing quality.

In order to achieve the above-described object, the present invention provides a plate cylinder structure of a printing unit in a rotary stencil printing machine, in which a stencil sheet is not directly wound around a metal plate cylinder, but a buffer layer is provided between the plate cylinder and the stencil sheet. In the stencil printing machine for corrugated board, the ink is supplied from the inside of the plate cylinder to the cylinder surface, and the supplied ink is supplied to the stencil sheet through the inside of the buffer layer. The thickness is 4 to 7 mm, the basis weight is 30 to 100 g / m ² , and the stencil sheet is a heat-sensitive stencil sheet .

According to the present invention, a plate cylinder structure of the printing unit in a rotary stencil printing machine, instead of winding the stencil sheet directly to the metal imaging drum, the intermediate buffer layer of the printing drum and the stencil sheet is provided, from the inside plate cylinder In the corrugated stencil printing machine in which ink is supplied to the cylinder surface and the supplied ink is supplied to the stencil sheet through the inside of the buffer layer, the buffer layer is made of a nonwoven fabric and has a thickness of 4 to 7 mm, basis weight 30-100 g / m ² and the stencil sheet is a heat-sensitive stencil sheet, so even if a large printing pressure is applied to the cardboard, the buffer layer is compressed so that the corrugated surface is uneven. Printing can be done neatly without applying excessive printing pressure to the cardboard, and the cardboard sheet or cardboard case can be printed while maintaining the maximum pressure resistance of the cardboard. Can do.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a plate cylinder structure of a printing unit in a rotary stencil printing machine, wherein a buffer layer 2 is provided on a metal plate cylinder 1 and a stencil sheet 3 is wound around the buffer layer 2. Further, a pressure drum 4 is provided opposite to the plate cylinder 1, and a corrugated cardboard, in this embodiment a cardboard sheet 5, is passed between the pressure drum 4 and the plate cylinder 1, and the ink permeated into the buffer layer 2 is passed through the stencil sheet. 3 is printed on the surface of the corrugated cardboard sheet 5 by the stencil sheet 3.

  As the material constituting the buffer layer 2, a nonwoven fabric, a glass fiber-impregnated material, a chemical fiber-impregnated material, a vinyl acetate foam-impregnated material, an impregnated foamed urethane material, a multi-bubble blanket material, or the like is used. As the sponge rubber material, foams such as NR, CR, EPDM, NBR, SI, and CR can be suitably used. Examples of natural fibers used as the nonwoven fabric include cotton, wool, hemp, pulp, silk, and mineral fibers. Chemical fibers include rayon, polyester, polyolefin, polypropylene, acrylic fiber, vinylon, nylon, cellulose, and aramid. Examples of the other fibers include glass fibers.

  The buffer layer 2 preferably has a mesh sandwiched on both sides. In addition, what stuck the mesh on one side may be used. The total thickness of the buffer layer 2 is 2 to 20 mm, and varies depending on the type and shape of the substrate (corrugated cardboard), but is preferably 4 to 7 mm.

  As the stencil sheet 3, a heat-sensitive stencil sheet is used, and its thickness is around 40 μm. Since the stencil sheet 3 has a thickness of about 40 μm, it can easily adapt to the irregularities on the surface of the corrugated cardboard sheet 5. An advantage of using a heat-sensitive stencil sheet as the stencil sheet 3 is that only a thermal printer is required for the plate-making apparatus. In comparison, the current plate making equipment for flexographic photosensitive resin plates includes film plate making equipment (film setter type: including developer), printing plate equipment (exposure machine, washing machine, dryer, solvent collector), and printing plate. Requires sticking equipment. Therefore, in the method of the present invention, the plate making time is shorter than the current photosensitive resin plate for flexo. Using heat-sensitive stencil paper will take 2 to 3 minutes. In the flexographic printing method, the current plate making time required about 3 hours. In the case of the current photosensitive resin plate system for flexo, the method of the present invention is unnecessary compared with the need for a step of attaching to a carrier sheet. In addition, compared to the current photosensitive resin plate for flexo, it does not require a developer and is superior from an environmental point of view without waste liquid. Cost reduction can be realized from the viewpoint of material cost.

  The method of the present invention is different from the usual “screen printing”, that is, a method in which a screen is stretched on a frame and fixed on four sides, and ink is put in the frame and squeegee is used for printing. This is a system in which the buffer layer surface (whole surface ink adhesion) is set at a predetermined position and can be immediately printed.

  The buffer layer 2 is mounted so as to cover the entire surface of the stainless cylinder (cylindrical shape) which is the plate cylinder 1, and holes are formed at equal intervals so that the ink 6 can easily pass through the entire surface of the stainless cylinder. 6 is uniformly supplied to the cylinder surface, and the ink 6 pushed out to the cylinder surface is filtered with a mesh on the surface of the buffer layer 2 to pass foreign matter, and passes through the inside of the buffer layer 2 to pass through the other mesh layer. The ink 6 passes uniformly and reaches the back of the stencil. (The number of screen mesh lines is 18 to 500 mesh, and 120 mesh is particularly suitable for cardboard). The purpose of providing the buffer layer 2 is to expand the printing pressure range and to control the ink amount.

  Thus, the preparation for printing is completed, and then the printing process is started. When the corrugated cardboard sheet 5 is supplied, the stainless steel cylinder (plate cylinder 1) rotates to apply printing pressure to the corrugated cardboard sheet 5 (see FIG. 2). At that time, the stencil sheet 3 with the buffer layer 2 built in does not crush the corrugated cardboard sheet 5, but flexibly contacts the corrugated surface of the corrugated cardboard sheet 5, and the ink 6 extruded from the stencil sheet 3 is corrugated. 5 is transferred to the surface of FIG.

In this way, stencil printing can be performed on corrugated cardboard. The following Table 1 and Table 1 show the results of experiments on the printing condition due to the difference in the thickness of the buffer layer 2 (using a nonwoven fabric) and the basis weight of the nonwoven fabric. It is shown in 2. As conditions at this time, in Table 1, the results in the case of corrugated cardboard sheet A flute, nonwoven fabric (rayon) basis weight 40 (g / m ² ), printing speed 60 sheets / min, ink viscosity 10 p, The results when the thickness of the corrugated cardboard sheet A flute, the buffer layer 2 (using a rayon nonwoven fabric) is 4 mm, the printing speed is 60 sheets / min, and the ink viscosity is 10 p are shown.

Furthermore, the results of comparative printing of pressure resistance strength and print quality using the same printing machine and the same corrugated cardboard were as follows. Corrugated cardboard is measured by measuring the compressive strength of corrugated cardboard box type: AF, box size: L11.5 cm × W10.0 × H10.0, front liner: K280, back liner: K210, A core: SD125 )did. Measurement temperature, humidity: 20 ° C., 50% RH, pressure resistance value when directly attached to a stainless steel cylinder: 109 N / m ²
Pressure strength value when buffer layer used in the present invention is built on a stainless steel cylinder ... 765 N / m ²
In addition to the above difference in pressure strength, there was a difference in print quality. Although there was no great difference in the print quality of line drawings such as characters, there was a difference in density in the solid print quality when the core core pattern was directly applied. With the buffer material built-in, it was possible to obtain a corrugated cardboard having good printing quality, good pressure resistance, and little deterioration in pressure strength.

The simplified side sectional view showing the embodiment of the present invention. The simplified side sectional view at the time of printing pressure of the present invention. The expanded sectional view of the cardboard sheet part at the time of printing. The simplified sectional side view which shows a prior art example. Sectional drawing of the corrugated cardboard crushed by printing pressure.

Explanation of symbols

1 printing cylinder 2 buffer layer 3 stencil sheet 4 impression cylinder 5 corrugated cardboard sheet 6 ink

Claims (2)

As a plate cylinder structure of a printing unit in a rotary stencil printing machine, a stencil sheet is not directly wound around a metal plate cylinder, but a buffer layer is provided between the plate cylinder and the stencil sheet, and ink is supplied from the inside of the plate cylinder to the cylinder surface. In the stencil printing machine for corrugated board , the supplied ink is supplied to the stencil sheet through the inside of the buffer layer .
The said buffer layer consists of a nonwoven fabric, the thickness shall be 4-7 mm, and a fabric weight shall be 30-100 g / m < ² > ,
A corrugated stencil printing machine , wherein the stencil sheet is a heat-sensitive stencil sheet . A 18-500 mesh mesh is affixed on both sides of the buffer layer, foreign matter is filtered by the mesh on the plate cylinder side of the ink extruded on the surface of the metal plate cylinder, and the ink that has passed through the inside of the buffer layer is meshed on the surface. The corrugated board stencil printing machine according to claim 1, wherein the cardboard stencil is allowed to pass uniformly .

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