JPS63126749A - Contact apparatus for printing press - Google Patents

Abstract

PURPOSE:To prevent the deflection of a contact roll, to obtain printing having beautiful finish free from halation in spite of a large printing width, to control the deflection of the contact roll by a sliding element and to eliminate necessity for providing a crown to the contact roll itself, by providing a backup roller for mechanically reinforcing the contact roll having a relatively small diameter so as to provide an appropriate interval from said contact roll. CONSTITUTION:In this contact apparatus, the support frame 112 constituting a part of a frame 110 and the first and second sliding elements 130, 140 are engaged in a slidable manner in order to minimize the play of a contact roll 120. The first and second backup rollers 132, 142 are respectively supported by the sliding elements 130, 140 in a freely rotatable manner and approach or spaced apart each other. The backup rollers 132, 142 can be moved over an equal distance by revolving the adjust screw 150 being one embodiment of the control means of the left and right symmetric sliding elements 130, 140.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for printing on a running web, and more particularly to a web abutting device for a so-called all-size rotary printing press.

(Prior Art) In a web rotary printing press, attempts have been made to print in all dimensions (i.e., repeat length) without replacing the plate cylinder, which is one of the printing means (for example,
Publication No. 7159).

As a result of intensive research aimed at solving these problems, the inventor of the present invention has concluded that by varying the running speed of the web and the circumferential speed of the printing cylinder (an example of printing means), it is possible to print with any repeat length. and has already filed several patent applications for inventions related to this (for example, Japanese Patent Application No. 61-253).
No. 67, Japanese Patent Application No. 61-71966, etc.).

After further research, the inventor found that although the printing and the web are in line contact, they have a certain width, and the size of this width affects the print finish.
It has been found that printing quality can be improved by making this line width as narrow as possible.

(Problems to be Solved by the Invention) The present invention is based on the above knowledge, and the objects of the present invention are as follows.

■Due to the difference between the running speed of the web and the peripheral speed of the printing means,
To reduce blur in printing as much as possible.

0 Minimize the negative impact of the contact device (equivalent to a conventional impression cylinder) on the web as much as possible.

To enable a contact device to uniformly bring a Kuep into contact with a printing means.

Other objects to be achieved by the present invention will become clear from the description and drawings below.

(Summary of the Invention) Therefore, the gist of the present invention is to provide a web contact device for a printing press that makes the running speed of the web different from the circumferential speed of the printing means, in which a small diameter contact is rotatably supported on a frame. A contact roll, a backup roller for preventing deflection of the contact roll, a slider rotatably supporting the backup roller and slidably disposed on the frame, and determining the position of the slider. This is a contact device for a printing press, which is equipped with a positioning means.

(Structure and operation of the invention) Details of the present invention will be described below with reference to embodiments illustrated in the drawings, but it goes without saying that the present invention is not limited to these embodiments.

FIG. 1 shows a printing plate 10 used in a printing press having an apparatus of the present invention.
FIG. This printing plate 10 is one of the printing means, and in the case of letterpress, a flexographic printing plate, a photosensitive resin printing plate, a 28 plate in the case of planographic printing, and a photosensitive sheet that can be wrapped around the printing cylinder in the case of intaglio printing. etc.

In cases where a printing plate is not attached to the printing cylinder, for example, when an engraving roll is used as the printing cylinder, the printing cylinder itself becomes the printing means, and in the case of offset printing, the printing cylinder, usually called a blanket cylinder, is the printing means. Applies to.

In this specification, the printing plate 10 will be mainly explained as a representative printing means, but it goes without saying that the printing means is not limited to printing plates.

The above-mentioned printing plate 10 is one in which the actual repeat length is larger than the length RP of the printing plate in the printing direction, that is, when printing with an enlargement of about 50% using the printing plate 10, a printing pattern as shown in FIG. 2 is obtained. is obtained. Therefore, the pattern of printing plate 10゛ is
During plate making, it is reduced in size in the rotational direction compared to the actual printed pattern.

It goes without saying that the printed portion does not need to cover the entire repeat length R, and can be arbitrarily selected within that range. Note that registration can be performed by printing the register marks 12 in the same manner as in normal printing.

On the other hand, if you want to make the repeat length R shorter than the length of the printing plate RP, make the plate at different wavelengths in the direction of rotation of the printing plate 10, and set the running speed of the web relative to the circumferential speed of the printing cylinder during printing. By making the pattern smaller, a reduced pattern is printed.

FIG. 3 shows a typical printing apparatus that performs printing by expanding and contracting the pattern of the printing means in the rotational direction of the printing cylinder, that is, in the running direction of the web.

To print by enlarging or reducing, the length of the printed pattern is adjusted by rotating the printing cylinder 50 at a predetermined ratio based on the running speed of the web. There are methods such as adjusting the running speed of the web 20 or the circumferential speed of the printing cylinder 50 while measuring the speed, and controlling the running speed of the web 20 at a predetermined ratio based on the circumferential speed of the printing cylinder 50. may be such that the traveling speed of the web 20 and the circumferential speed of the printing cylinder 50 are always kept at a constant ratio. Which of the above methods to adopt depends on conditions such as whether to use an in-line type or an offline type, but in Fig. 3, since the device performs offline type printing, the circumferential speed of the printing cylinder 50 An example is shown in which the running speed of the web 20 is controlled based on .

A printing plate 10 as shown in FIG. 1 is attached to the printing cylinder 50 over almost its entire circumference, and an appropriate amount of ink is supplied to the printing plate 10 from an inking device 60. When enlarging printing is performed using the printing plate IO as a reference, an amount of ink is applied that is approximately proportional to the enlargement ratio, and when performing reduction printing, an amount of ink that is approximately proportional to the reduction ratio is applied.

The amount of ink can be adjusted, for example, by adjusting the clearance between the pumping roll 62 and the transfer roll 64 in the roll coater type inking device 60 shown in FIG. 3, or by changing the rotation ratio of these rolls 62 and 64. It can be done by

The printing cylinder 50 is driven by a motor 54 via a first gear 52 . The power of the first gear 52 is separately supplied to the second gear 52.
A transmission 70, which is one of the speed regulating means, is connected via a gear 56.
transmitted to. This transmission 70 is provided with a gear ratio setting tool and a scale so that the gear can be shifted at a predetermined ratio, but these are not shown because they are conventional.

In addition, in FIG. 3, a mechanical transmission device 70 is used as a speed regulating means.
However, it is needless to say that it is not limited to a mechanical type and may be an electrical or electronic type.

The output from the variable speed bag 70 is transmitted via a third gear 72 to a web drive roll 74, and a nip roll 76 is in contact with this drive roll 74 via the web 20. Therefore, the running speed of the web 20 unwound from the unwinder 22 is controlled to a predetermined ratio to the circumferential speed of the printing cylinder 50.

The web 20 whose running is controlled to a predetermined ratio is the rewinder 2
4, it contacts the printing cylinder 50 via the guide roll 78. In ordinary printing apparatuses, an impression cylinder is used to bring the web into contact, but the present invention is different from these and uses a contact device 100 that is not limited to a cylinder.

When the main part of this contact device 100 is a rotating roll, the diameter of the roll is preferably 10 mm to 140 mm, more preferably 20 mm to 100 mm. The most preferred range is 20 mm to 50 mm. For more details, please refer to the description of the embodiments below.

If the diameter of the roll is less than 10 mm, it will be difficult to make the roll itself and it will be extremely difficult to support the roll in a rotatable manner, which is not practical. From the point of view of eliminating deflection of the roll, the larger the diameter of the roll, the better.

On the other hand, increase the diameter of the roll to 200mm lol
-)

The rate of change between the web 20 and the printing cylinder 50 is 1.13 or 089
In this case, the same margin zone (lightly printed area) as with normal printing can be obtained when the roll diameter is approximately 50 mm, and the finish that is almost the same as that of constant speed printing is obtained when the roll diameter is approximately 30 mm. When it comes to millimeters.

The above change rates of 1.13 and 0.89 apply continuously to all dimensions when preparing three types of printing cylinders 50 (large, medium and small) (however, the maximum dimension is 113 times the circumference of the large printing cylinder). There is a limit)
These are the typical maximum and minimum values of the rate of change covering the range. In other words, if the speed of each printing cylinder or web can be changed at a ratio of 0.89 to 113 times that of constant speed printing, all dimensions within the above-mentioned maximum dimension can be covered.

When the printing cylinder 50 is made into two types, large and small, the setting range is 0.84 to 1.
19 times, 0.91 to 1.09 times when using 4 types,
If there are five types, all dimensions can be covered within a variable range of 0.93 to 1.07 times. Even if there are six or more types of printing cylinders 5o, there is no significant difference in printing accuracy.

In the case of flexographic printing, it is sufficient to have two to five types of printing cylinders, and especially when high-definition printing such as process color printing is not performed, two or three types of printing cylinders are sufficient.

If only one type of printing cylinder is used, the variable range becomes large, making it difficult to perform high-precision printing. As a result of the experiment, the marginal zone when printing with a change rate of 1.42 times using an impression cylinder with a diameter of 100 mm was comparable to that when sheet printing was performed using a flexographic method on corrugated board. As can be seen from the example, the smaller the rate of change, the smaller the marginal zone.
When one type of printing cylinder is used, sufficiently beautiful printing can be obtained within a limited variable range.

FIG. 4 is a side view of one embodiment of the abutting device of the present invention with a portion omitted, and FIG. 5 is a sectional view taken along the line V-V. The frame 110 rotatably supports the small-diameter contact roll 120 as described above. The length of this contact roll varies depending on the type of web to be printed, but for example, it is 1,800 mm to 2,200 mm for corrugated cardboard liner, and 60 mm for bag web.
Often 0 mm to 1000 mm.

If the abutment roll 120 of the above length is used alone, deflection will occur, but in the case of a printing machine, the tolerance for deflection is several tens of microns (μm) or less, so high precision members are used and These members must be assembled and adjusted with high precision.

In the present invention, in order to minimize play (or backlash), a support frame 112 and first and second sliders 130, which constitute a part of the frame 110, are provided. 140 are slidably fitted. For this fitting, either side may be concave or convex, but from the viewpoint of ease of manufacture and accuracy, the frame 110 side is formed into a groove-shaped guide 106, and the first and second slider 13
It is preferable to provide the convex portion on the 0.140 side. Although the support frame 112 constitutes a part of the frame 110, it goes without saying that it may be formed integrally with the support frame 112, or that separate parts may be joined together to form an integral structure.

First and second back-up rollers 132 and 142 are rotatably supported on the first and second sliders 130 and 140, respectively, and the web 20 rotates the abutment roll 120. The backup rollers 132 and 142 also rotate accordingly. These rollers 132.
There is no particular limitation on the structure of 142, and it may be disk-shaped, cylindrical, or spherical. In short, any material that can support the abutment roll 120 with high accuracy and low frictional resistance is sufficient. Although the arrangement pitch of the backup rollers depends on the diameter of the contact roll 120, the tension of the web 20, etc., it is usually good to have a pitch of one every 20 to 30 centimeters.

The first and second sliders 130 and 140 are arranged in the axial (i.e. longitudinal) direction of the abutment roll 120 and
It can slide in the direction perpendicular to the normal direction of the 0th circumference. That is, the first and second backup rollers 132.14
2 move closer to each other or move away from each other. When these rollers 132 and 142 approach, the point of contact with the abutting roll 120 separates from the position of the support frame 112, and conversely, when the rollers 132 and 142 move apart, the pedestal moves closer to the old box frame 112. (6) Normally, the first and second backup rows 2132 and 142 have substantially the same diameter, so when these rollers 132 and 142 approach or separate, they move the same distance in opposite directions. .

The first and second backup rollers 132°142
In order to move the same distance, it is possible to move the left-right symmetrical first and second sliders 130 and 140 by rotating the adjusting screw 150, which is an example of adjusting means. The right-hand thread 152 and the left-hand thread 154 are integrally formed, and the right-hand thread 152 and the first slider 13
0, the left-hand screw 154, and the second slider 140 are screwed together, respectively. When the adjusting screw 150 is rotated clockwise from the right-hand screw 152 side, the first and second sliders 130.
140 are spaced apart from each other, and conversely, when rotated counterclockwise, they approach each other.

If left as is, there is a risk that the adjusting screw 150 will rotate by itself, so it is preferable to use the nut 156 to stop it from rotating. The nut 156 keeps the distance between the first and second sliders 130, 140 constant, but since these sliders 130, 140 can move within the guide 114, they should not move. It is necessary to determine the location. As an example of this positioning, for example, as shown in FIG.
8 and a stator 160 attached to the support frame 112. This retaining portion 158 rotatably engages with the stator 160, and the adjusting screw 150 does not move in the axial direction.

Incidentally, as an example of positioning means, the stator 160 is mounted on the support frame 1.
12, but either one or both sliders 130
．． 140 is provided with a thumbscrew or the like, and its tip is attached to the support frame 112.
It is also possible to prevent the slider 130, 140 from moving by strongly contacting the slider 130, 140.

Since the small-diameter contact roll 120 is made rotatable and reinforced in this way, the contact roll 120 has a deflection strength equivalent to that of a normal-sized impression cylinder, and can realize line contact with an extremely narrow width. be.

The web 20 that has been printed through the abutment device 100 within the range described above is wound up by the rewinder 24 in a conventional manner to complete the printing.

In FIG. 3, a monochrome printing apparatus is illustrated, but the invention is not limited to this, and it goes without saying that a multicolor printing apparatus can be used.

(Example) Using an apparatus as shown in FIG. 3, a printing test was conducted using the diameter of the contact roll as a parameter. The main test conditions are as follows.

Printing speed: 100 meters/min Print cylinder diameter: 260 mm Plate: Photosensitive resin plate for flexo printing. 7mm thick. (Manufactured by Asahi Kasei Corporation. Product name: APR). Note that the dimensions of the printing plate are expanded or contracted according to the rate of change.

Planned printing width of test print line: 0.4mm IJ meter Direction of test print line: Parallel to the printing cylinder axis Web used: Corrugated board liner (K liner, basis weight 220g/sqm) Ink used:
Change rate of water-based flexo ink for corrugated board liner: 1.13 times when enlarged 0.89 times when reduced The width of the thin printed area was measured using a loupe with a scale.

In addition, for areas where the printing is too light, place it in the center of the print line when printing at full size, and towards the rear in the running direction of the web when printing at enlarged size.
When zoomed out, it appears in front. The results are shown in the table.

Table *2 B shows that, in principle, the smaller the diameter, the better the print finish, based on the results of the width of the entire print line (unit: millimeter). However, when the web is a corrugated liner, the liner is thick and it is not desirable to reduce the diameter to less than 20 millimeters because bending the liner will cause warping and internal stress.

On the other hand, when the diameter is about 30 mm, the print finish is almost the same as full-size printing, and even if the diameter is further reduced to about 20 mm, the print quality does not improve any further. This is considered to be due to the characteristics of the flexo printing method itself.

The enlargement and reduction ratios shown in the table represent the range that can cover all repeat lengths if there are three types of printing cylinders: large, medium, and small. In addition, when using three types of printing cylinders (large, medium, and small), use a turret type, and when one of them is printing, the printing plate can be attached to and removed from the other two, reducing the time lost when writing on the board. can be shortened.

(Effects of the Invention) As described above, the device of the present invention has a relatively small-diameter abutment roll and backup rollers that mechanically reinforce this abutment roll at appropriate intervals, thereby preventing deflection of the abutment roll and printing. Even if the width is wide, it is possible to obtain a beautiful finished print without blurring.

Since the deflection of the abutment roll can be adjusted by the slider, there is no need to provide a crown on the abutment roll itself, and the abutment roll can be manufactured easily.

Since the diameter of the abutment roll is small, a beautiful stamp surface can be obtained even in printing where the running speed of the web and the peripheral speed of the printing means are different.

[Brief explanation of the drawing]

FIG. 1 is a developed view of a printing plate used in a printing press equipped with the device of the present invention, FIG. 2 is a plan view of a sheet enlarged and printed by the printing plate, and FIG. FIG. 4 is a side view of the device of the present invention, and FIG. 5 is a sectional view taken along the line V-V in FIG. 4. 20... Web, 30... Contact means, 5o... Print cylinder, 60... Inking device, 7o... Transmission device,
100... Contact device, 110... Frame, 120
... Contact roll, 130, 140 ... Slider, 1
32, 142...backup roller, 150...
・Adjustment means.

Claims (6)

[Claims] (1) In a web contact device for a printing press that makes the running speed of the web different from the circumferential speed of the printing means, (a) a small-diameter contact roll rotatably supported on a frame; and (b) a corresponding contact roll. a backup roller that prevents deflection of the roll; (c) a slider that rotatably supports the backup roller and is slidably disposed on the frame; and (d) a position of the slider. A contact device for a printing press, comprising: an adjusting means for adjusting; and (e) a positioning means for determining the position of the slider. (2) The diameter of the contact roll is 20 mm to 1
The abutting device for a printing press according to claim 1, characterized in that the diameter is 0.00 mm. (3) The contact device for a printing press according to claim 1 or 2, wherein the adjustment means is an adjustment screw integrally equipped with a right-hand thread and a left-hand thread. (4) The contact device for a printing press according to any one of claims 1 to 3, wherein the positioning means is attached to the frame. (5) The contact device for a printing press according to any one of claims 1 to 3, wherein the positioning means is attached to the slider. (6) The printing machine according to any one of claims 1 to 5, wherein the slider is slidable in a direction perpendicular to the axial direction of the contact roll. Contact device for use.