JPH0552790B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a sheet-fed vinyl printing machine. More specifically, mainly plastic bags,
It also relates to a printing machine that can print letters and symbols such as designs and store names in small batches on objects with handles and gussets, as well as on vinyl films.

[Conventional technology]

Until now, there has been no printing machine that can print a certain amount of high-quality prints on plastic bags after they are completed.

The reasons for this are as follows. A typical plastic bag 50 used as a handbag is shown in FIG. To make such a plastic bag 50, first, a vinyl tube 81 or sheet as shown in FIG. Seal 5
2, 54→cutting of the tube 81 or sheet. In this way, the plastic bag 50 has gussets 57 and 58 at the opening and bottom, and a handle 55 protrudes from the center of the opening.

As mentioned above, since the plastic bag 50 has the gussets 57 and 58 after being made into a bag,
The thickness differs in some parts, making it difficult to apply an appropriate printing pressure to the part to be printed (main body part 51 in many cases). Further, the handle 55 makes it difficult to pass through the pressurizing device or peripheral mechanism without getting stuck. This situation is the same in plastic bags having different shapes from the plastic bag 50 described above, and for this reason, a completed sheet-fed printing machine for plastic bags has not been realized to date.

Therefore, currently used printing methods for plastic bags are limited to continuous printing only. Continuous printing is, as shown in FIG. 17, in which a tube 81 wound around a single roll 80 is passed between printing machines 82 as a continuous body, and the printed tube 81 is printed. This is a printing method in which the paper is wound onto the winding body 83 again. Note that one printing machine 82 is used for monochrome printing, and a plurality of printing machines are used for multicolor printing. Processing into a bag is carried out by unwinding the tube 81 from the printed roll 83 again and following the steps of folding, gluing the handle, heat sealing, and cutting. Therefore, in this continuous printing, there are no inconveniences caused by the presence of gussets or handles.

[Problem that the invention seeks to solve]

However, in the case of continuous printing, one roll of roll 80 usually has a length of 3,000 to 5,000 m, and the same printing is applied to all of this, so for example, 6,000 to 5,000 m.
Although it is suitable for printing in large quantities, such as around 10,000 sheets, it is not cost-effective for printing small lots, such as 100 to 3,000 sheets, and it is not widely used because of its poor work efficiency. This is the current situation.

However, in response to the recent diversification of daily life and the diversification of trade and distribution channels, finished plastic bags are now being printed with additional designs such as one-point patterns, as well as store names and various events. Demand for printing characters and symbols for display is increasing.

In view of the above circumstances, the first object of the present invention is to provide a printing machine that can print small lots of plastic bags at low cost and with high efficiency, which has not been done in the past.

A second object of the present invention is to provide a printing machine suitable for printing on vinyl films other than bags.

[Means to solve the problem]

The sheet-fed vinyl printing machine of the present invention is a printing machine that prints each independent plastic bag one by one, and includes (a) a transverse feed that feeds the plastic bags at high speed in a direction perpendicular to the feeding direction to the printing device; a conveyor; (b) a presser plate disposed on the top surface of the transverse conveyor for holding down the plastic bag and correcting wrinkles in the plastic bag while the plastic bag is being conveyed at high speed on the transverse conveyor; ) a forward conveyor that feeds the plastic bags from the cross conveyor in the direction of the printing device; a stopper for stopping the plastic bag and positioning the printing position of the plastic bag; (e) a suction transfer device for transporting the plastic bag from the lateral conveyor to the forward conveyor; and (f) for directing the plastic bag toward the printing machine on the forward conveyor. (g) A pressing member disposed on the upper surface of the advance conveyor that presses down the plastic bag on the advance conveyor to correct wrinkles during forward conveyance, and (g) ends on the same side of each of the plate cylinder and the impression cylinder. (h) a printing device having a width shorter than the axial length of the plate cylinder;
A resin letterpress plate whose axial position on the plate cylinder can be arbitrarily changed according to the printing position on the plastic bag, and (i) a printed plate that has passed between the impression cylinder and the plate cylinder In order to guide the plastic bag downward while following the surface of the impression cylinder, it is characterized by a guide roller that is elastically pressed against the surface of the impression cylinder by a spring.

In this specification, the term "sheet" refers to short sheets of vinyl film or bags, each of which is separate, rather than a long sheet. Furthermore, the term "vinyl film or bag" refers to a film made of synthetic resin such as polyethylene or polyvinyl chloride, or a bag made of such a film.

〔Example〕

Next, embodiments of the present invention will be described.

FIG. 1 is a schematic side view of a printing press according to an embodiment of the present invention, FIG. 2 is a perspective view of the supply mechanism in the embodiment, FIG. 3 is a diagram explaining the principle of the suction transfer device, and FIG. A schematic side view of the register mechanism in the embodiment, FIG. 5 is a plan view of the feed roller 27,
Fig. 6 is a schematic side view of the inking device in the same embodiment, Fig. 7 is a perspective view showing the ink forming roller and doctor, Fig. 8 is a front view showing the plate cylinder and the impression cylinder, and Fig. 9 is the impression cylinder. Explanatory diagram of the lifting mechanism, 10th ~
Figure 11 is a side view and rear view of the guide roller, the first
Figure 2 is a perspective view of a typical type of plastic bag that can be printed with the printing machine of the present invention, Figure 13 is an end view taken along line I-I in Figure 12, and Figures 14 and 15 are perspective views of other plastic bags. It is a diagram.

First, the overall configuration of a printing press according to this embodiment will be explained based on FIG. 1. This printing press is composed of a supply device A, a register mechanism B, an inking device C, a pressure device D, and a discharge device E. Of particular importance are the pressure device D, which is made up of a plate cylinder 1, a plate 4, and an impression cylinder 2, and the inking device C, which uses an anix roller as the inking roller 3, and here the features of the present invention as described later reside. . The supply device A and the discharge device E can be arbitrarily designed depending on the installation location and printing performance of the printing press. Note that the feeding device A is a device that feeds the plastic bag to be printed toward the pressurizing device D, and the register mechanism B is a mechanism for positioning the printing position, and the discharging device E
is a device that sends out printed plastic bags using a pressurizing device D.

Next, the printing press of this embodiment will be explained in detail in the order from supply to discharge.

FIG. 2 shows details of the supply device A.
This feeding device A has a cross feed table 5 and a front feed table 6, which are arranged in an approximately L shape.
A lateral feed conveyor 7 and a suction transfer device 8 are arranged on the front feed table 6, and a forward feed conveyor 9 is arranged on the front feed table 6.

Furthermore, the left side part of the horizontal feed table 5 in the figure is the work table 5a.
Here, a space is provided in which a plastic bag 50, which is the printing material, is first placed and then spread out flat.

The illustrated plastic bag 50 is the same as that shown in FIG. 12 earlier, and has a handle 55 and a gusset 5.
It has 7,58. Although the printing machine of the present invention can print on various forms of plastic bags and on vinyl films before being made into bags, the case where printing is performed on the illustrated type of plastic bag 50 will be described below as an example. In addition, a plastic bag 5 spread out flat
0 has wrinkles created when it was folded 59
However, measures to correct such wrinkles 59 have been taken as described later.

Now, the plastic bags 50 on the workbench 5a are manually fed one by one onto the transverse feed conveyor 7. Note that in order to automate the work, an appropriate air feeding mechanism may be used to feed the air. In that case, the plastic bags 50 can be pulled out one by one from the bottom of the stack and fed.

The lateral conveyor 7 moves in the direction of arrow T, and its speed is about three times that of the forward conveyor 9. A holding plate 11 is placed on each conveyor belt 7a. This holding plate 11 is an elongated steel plate curved in the longitudinal direction, and the front part is slightly raised and fixed to the support frame 12, and the rear part is brought into contact with the conveyor belt 7a by its own weight. Therefore, when the plastic bag 50 is sent to the transverse feed conveyor 7, the plastic bag 50 is sandwiched between the conveyor belt 7a and the presser plate 11 and is fed laterally at high speed. The wrinkles 59 that have formed on the surface are corrected and flattened.

Furthermore, a stopper 13 and a stopper 14 are provided on the traverse conveyor 5 at right angles to the traverse conveyor 7, and in parallel to the traverse conveyor 7, respectively. These stoppers 13, 14
Therefore, the plastic bag 50 fed by the transverse conveyor 7 is always stopped at a fixed stop position. Therefore, the next operation of forwarding by the suction transfer device 8 is reliably performed.

The suction transfer device 8 uses a suction cup 15 to pick up a plastic bag 50.
It adsorbs and sends it to the front edge of the forward conveyor 9. In the illustrated device 8, two suction cups 15 are fixed to a support frame 16, and they repeat reciprocating motions along a trajectory shown by a chain line 17, feeding one plastic bag 50 with each movement. As shown in Fig. 3, the suction principle is as shown in Fig. 3.
This utilizes the pressure difference between the air inside the air chamber 5 and the outside air that is created by suctioning the air inside. Note that the pump 16
This is a simple mechanism in which the piston 16b inside the cylinder 16a is moved back and forth, and the piston 16b is pulled in synchronization with the forward movement of the suction cup 15.

The advance conveyor 9 shown in FIG. 2 is a device that feeds the plastic bags 50 sent by the suction transfer device 8 toward the pressurizing device D. Therefore, the conveyor belt 9a of the forward conveyor 9 is driven in the direction of arrow F. Four presser rollers 18 are in contact with the upper surface of the advance conveyor 9, and the plastic bags 50 conveyed by the conveyor 9 are
is pressed down from the top to ensure reliable feeding. The support structure for each of these presser rollers 18 is arbitrary and can be freely designed, but it is possible to freely move each presser roller 18 in the feeding direction of the conveyor 9 (i.e., the front and back direction), in the lateral direction, and even in the vertical direction. Preferably, the position can be adjusted.
Further, although the illustrated presser rollers 18 are supported by a support shaft 19, each roller 18 may be supported independently by appropriate means without using the support shaft 19. In any case, in this way, each pressing roller 18 can freely select the position to press according to the position of the gussets 57, 58 of the plastic bag 50 to be printed.

A frame body 21 that supports the support shaft 19 of the presser roller 18
A presser plate 22 is attached to the holder. This presser plate is the same as the steel plate 11 used in the traverse conveyor 7, and a wide resin sheet 23 is adhered to its lower surface. The plastic bag 50 sent on the conveyor 9 is passed under the sheet 23 which is pressed down by the weight of the presser roller 18 and the presser plate 22, thereby increasing the friction between the plastic bag 50 and the conveyor belt 9 and ensuring that it is properly registered. It is sent towards mechanism B.

In FIG. 4, register mechanism B is shown. This register mechanism B is for temporarily stopping the feeding of the plastic bag 50 and correctly regulating the position of the plastic bag 50 before being fed into the pressurizing device D.
In the same figure, 25 is a pre-inspection, which is fixed to a roller 26. As the roller 26 rotates, the pre-inspection 25 is tilted in the direction of arrow G. A feed roller 27 is disposed above the roller 26 so as to be movable up and down, and when the feed roller 27 descends and rotates, the plastic bag 50 can be advanced. On the left side of the front detection 25 in the figure, a light emitting element 28 and a light receiving element 29 of a phototube are arranged vertically facing each other, so that it can be detected that the plastic bag 50 has advanced this far.

Note that the feed roller 27 is fitted onto a support shaft 32 as shown in FIG.
2 is fixed to the tip of an arm 33 that is swingably attached to a fixed shaft 34. By sliding the feed roller 27 on the support shaft 32, the mounting position is changed between the gussets 57, 58 of the vinyl bag 50, which is the printing material, and the main body portion 51.
It is designed so that it can be pressed separately.

Assuming that a plastic bag 50 is now being sent by the forward feed conveyor 9, the front edge of the bag 50 is at the front check 2.
5, the forward movement of the bag 50 stops. Then, when the feed roller 27 descends and rotates in the direction of the arrow,
At the same time, the rollers 26 rotate to tilt the front checker 25 forward and send the bag 50 forward while pinching the bag 50. When the plastic bag 50 moves forward a little, it blocks the light beam between the light emitting element 28 and the light receiving element 29, and this is used as a detection signal to operate a solenoid, which will be described later.

An inking device C is shown in FIGS. 6-7.
The ink applicator roller 3 is an anix roller having a grid of minute depressions (hereinafter referred to as an anix grid 36) like a gravure cell on the entire surface.
This inking roller 3 is in contact with the plate cylinder 1 and is directly immersed in ink 38 contained in an ink tray 37. Ink 38 is supplied to and discharged from the ink tray 37 by a pump 39. ink 38
Liquid flexo inks such as pigment inks dispersed in solvents or dyes dissolved in alcohols are used, but inks with high quick-drying properties are particularly suitable.

A doctor 41 is in contact with the surface of the ink application roller 3, and the doctor 41 inks the ink 3.
8 is scraped off, and the ink 38 is left only in the aniculates 36. The amount of ink to be transferred to the plate 4 is basically determined by the cell volume of the anitic grid 36, so several ink applicator rollers 3 with different cell volumes are prepared, and the amount of ink to be transferred to the plate 4 is determined depending on the type of printed material. It is recommended that you replace it as appropriate. Furthermore, since the amount of ink can be regulated using the doctor 41, quantification and uniformity of ink application can be achieved.

A pressurizing device D is shown in FIGS. 8-9. The pressurizing device D is composed of a plate cylinder 1, a plate 4, and an impression cylinder 2. The plate cylinder 1 is the main body portion 4 to which the plate 4 is attached.
2, and a relief part 4 with a small diameter on one end side.
3 is formed. Similarly, the impression cylinder 2 has a main body portion 44 to be pressed against the plate 4, and a relief portion 45 having a small diameter is formed at one end thereof. Since the relief portion 43 of the plate cylinder 1 and the relief portion 45 of the impression cylinder 2 are both provided at the end of the same side, there is a space 4 between the relief portions 43 and 45 facing each other.
I can do 6. This space 46 is a space for the handle 55 of the plastic bag 50 to be printed to pass through without getting caught on anything during printing.

A plate 4 is attached to the surface of the plate cylinder 1. A letterpress plate made of resin is used as the plate 4, and its dimensions and attachment position can be freely selected. By appropriately selecting the size and adhesion position of the plate 4, the main body portion 51 between the gussets 57 and 58 of the vinyl 50 is
It is possible to print only on the gussets 57 and 58 or only on the gussets 57 and 58.

The impression cylinder 2 has one end supported by a crank 47, and the lower end of the crank 47 is connected to a solenoid 48. This solenoid 48 is actuated by the detection signals from the phototubes 28 and 29 described above in connection with the register mechanism B, and pushes the impression cylinder 2 upward. As a result, the plate cylinder 1 and the impression cylinder 2 are pressed together with an appropriate printing pressure. Therefore, the plastic bag 50 fed by the feed roller 27 of the register mechanism B is sandwiched between the plate cylinder 1 and the impression cylinder 2 and pressed against the plate 4, and the plate cylinder 1 and the impression cylinder 2 are It is designed to be printed and sent out during one revolution.

Note that guide rollers 61 and 62 as shown in FIGS. 10 and 11 are arranged on the impression cylinder 2 to guide the printed plastic bag 50 downward. Guide roller 61 and guide roller 62 are supported by arms 63 and 64, respectively, and are attached to shaft 65. A tension spring 66 is stretched between the support shaft 61a of the roller 61 and the support shaft 62a of the roller 62, so that the rollers 61 and 62 are drawn to each other. The guide roller 61 is in contact with an obliquely upper portion of the impression cylinder 2, and the guide roller 62 is in contact with a portion slightly below the right side of the impression cylinder 2, supported by a stay 67. Therefore, the plastic bag 50, which is the printing material, sent out from between the plate cylinder 1 and the impression cylinder 2 is guided by guide rollers 61, 62 and sent downward.

The printed plastic bags 50 thus sent downward from the impression cylinder 2 are sent to the collection station S by the discharge device E shown in FIG. As the discharge device E, a conveyor 68 disposed below the impression cylinder 2 and a roller conveyor 69 connected thereto are used. Furthermore, roller conveyor 6
It is preferable to arrange a drying device 71 above 9 as necessary. Roller conveyor 6 by drying device 71
9. When the ink in the plastic bag 50 immediately after printing is dried and accumulated, the plastic bag 50
This is preferable because printing does not become smudged even if the two are stacked one on top of the other.

Next, the operation of this embodiment will be explained.

The supply device A can intermittently and continuously supply the plastic bags 50 to be printed one by one, and the registration mechanism B performs positioning during printing one by one. Thereafter, a plastic bag 50 is fed between the plate cylinder 1 and the impression cylinder 2, and while the plate cylinder 1 and the impression cylinder 2 each make one revolution, the ink on the plate 4 is transferred to the plastic bag 50.
is transferred and printed. The printed plastic bag 50 is guided by guide rollers 61 and 62 and sent from the surface of the impression cylinder 2 to a conveyor 68, and then sent to a collection station S by a roller conveyor 69. If a drying device 71 is provided, the ink immediately after printing is dried by it.

In the apparatus of this embodiment, the plate 4 is a letterpress plate, and when it is attached to the surface of the plate cylinder 1, only the plate surface protrudes, so there are gussets 57, 58, etc., and the plastic bag has an uneven thickness. Even for 50,
Printing can be performed with appropriate printing pressure, resulting in high print quality. Further, by changing the size of the printing plate 4 and the adhesion position, it is possible to avoid or print on the gusset part of any type of plastic bag 50. In a normal printing press, the handle 55 of the bag gets caught between the plate cylinder and the impression cylinder or other mechanical parts and interferes with normal operation. space between 4
6 eliminates any chance of jamming or the like, so even if the bag is a plastic bag with a handle 55 attached, it will not interfere with printing.

Furthermore, in this embodiment, the handle 55 and the gussets 57, 5
It is possible to continuously print about 2,400 to 3,000 plastic bags 50 of various shapes with numbers 8 on them per hour, depending on the size. Therefore, it is ideal for so-called small lot printing, where the number of copies is too small to be printed using conventional continuous printing methods, but is too large for home printing machines, etc., and it is a low-cost printer that meets such demand. You can respond with

Furthermore, this embodiment is configured to use quick-drying flexographic ink, thereby making printing on the plastic bag 50 easy and ensuring high printing quality.

As described above, the printing machine of this embodiment can print on various types of plastic bags, but the
Examples other than the plastic bags shown in the figure are 14th and 15th.
Shown in the figure. The plastic bag 50 shown in FIG. 14 has gussets 57 and 58 on both side edges, and the handle 55 is formed by punching a hole 59. Furthermore, the plastic bag 50 shown in FIG. 15 is a rectangular bag without a gusset, and has a handle 55 formed by punching a hole 59 therein. In both cases, the store name and other information (Pt) are printed on the main body.
Of course, it is also possible to print on plastic bags in other forms than these. Furthermore, it is not limited to vinyl bags, but can also be printed on paper or canvas bags, and can also be printed on simple vinyl films that are not made into bags.

〔Effect of the invention〕

According to the present invention, printing on small lots of plastic bags, etc., which has not been realized in the past, can be performed at low cost and with high efficiency.

[Brief explanation of drawings]

FIG. 1 is a schematic side view of a printing press according to an embodiment of the present invention, FIG. 2 is a perspective view of the supply mechanism in the embodiment, FIG. 3 is a diagram explaining the principle of the suction transfer device, and FIG. A schematic side view of the register mechanism in the embodiment, FIG. 5 is a plan view of the feed roller 27,
Fig. 6 is a schematic side view of the inking device in the same embodiment, Fig. 7 is a perspective view showing the ink forming roller and doctor, Fig. 8 is a front view showing the plate cylinder and the impression cylinder, and Fig. 9 is the impression cylinder. Explanatory diagram of the lifting mechanism, 10th ~
Figure 11 is a side view and rear view of the guide roller, the first
Figure 2 is a perspective view of a typical type of plastic bag that can be printed with the printing machine of the present invention, Figure 13 is an end view taken along line I-I in Figure 12, and Figures 14 and 15 are perspective views of other plastic bags. 16 is a perspective view showing a rolled up vinyl tube, and FIG. 17 is an explanatory diagram of a continuous printing method. (Main symbols in the drawing) 1: Plate cylinder, 2: Impression cylinder,
3: Ink forming roller, 4: Plate, A: Supply device,
B: Register mechanism, C: Inking device, D: Pressurizing device, E: Ejecting device.

Claims (1)

[Scope of Claims] 1. A printing machine that prints individual plastic bags one by one, comprising: (a) a transverse conveyor that feeds the plastic bags at high speed in a direction perpendicular to the feeding direction to the printing device; (b) a presser plate disposed on the upper surface of the transverse conveyor for pressing the plastic bag and correcting wrinkles in the plastic bag while the plastic bag is transversely conveyed at high speed on the transverse conveyor; (d) a forward feed conveyor that feeds the plastic bag from the feed conveyor in the direction of the printing device; (d) a plastic bag provided at the intersection of the cross feed conveyor and the forward feed conveyor for stopping the plastic bags sent by the cross feed conveyor; a stopper that positions the printing position of the plastic bag; (e) a suction transfer device that transports the plastic bag from the lateral conveyor to the forward conveyor; and (f) the forward conveyor that forwards the plastic bag toward the printing machine. (g) A pressing member placed on the top surface of the advance conveyor that presses down the plastic bags on the advance conveyor to correct wrinkles in the bags; (h) a printing device having a width shorter than the axial length of the plate cylinder;
A resin letterpress plate whose axial position on the plate cylinder can be arbitrarily changed according to the printing position on the plastic bag, and (i) a printed plate that has passed between the impression cylinder and the plate cylinder A sheet-fed vinyl printing machine characterized by a guide roller elastically pressed against the surface of the impression cylinder by a spring in order to guide the plastic bag downward while following the surface of the impression cylinder.