JPH05330226A - Rotary screen printing apparatus - Google Patents

Abstract

PURPOSE:To always obtain printed matter having the best printing density and free from strike-through automatically or on the basis only of the input data from an operation panel according to the change of the printing condition data such as temp., a printing speed or the like in a rotary screen printing apparatus. CONSTITUTION:In a rotary screen printing apparatus wherein ink I is supplied to the stencil paper 2 wound around the outer periphery of a cylindrical perforated plate cylinder 1 and a press roller 5 is brought into contact with printing paper 4 under pressure to perform printing, the ratio of the number of rotations of the cylindrical perforated plate cylinder 1 rotated by a perforated plate cylinder driving part 6 to the number of rotations of the form roller 3 rotated by an inking drive part 7 is variable on the basis of printing condition data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stencil printing machine, and more particularly to a rotary stencil printing machine in which the adjustment of print density and set-off are improved by the information on printing conditions.

[0002]

2. Description of the Related Art In a conventional rotary stencil printing machine, factors affecting print density and set-off are pressure contact force of an inking roller to a plate cylinder, temperature in a rotary stencil printing machine, printing speed, etc. Has been. Among these factors, a method and apparatus for varying the pressure contact force of the ink application roller to the plate cylinder to adjust the print density by adjusting the eccentric cam or the like are known. is there. However, it is extremely difficult to adjust the left and right eccentric cams and the like so that the pressure contact force becomes uniform in consideration of the uneven density by this method.

In addition, there is a method of adjusting the print density by varying the press contact force of the press roller of the press roller which presses against the plate cylinder. In this method, the spring pressure is generated according to the set print density information. It is also known to appropriately change the press pressure. In this method, the press pressure must be lowered in order to obtain an appropriate print density when the printing speed is low or when the inside of the rotary stencil printing machine is at a high temperature. By reducing the press pressure, the ink cannot be pushed into the printing paper, and as a result, a large amount of the ink adheres to the printing paper, and it is not possible to prevent set-off. Further, when the press pressure is increased, there arises a problem that the number of printable sheets is reduced due to tearing or peeling of the stencil sheet. Therefore, in the conventional rotary stencil printing machine, it is very difficult to adjust the print density and prevent set-off in response to changes in printing conditions such as temperature and printing speed in the rotary stencil printing machine. There was a problem.

As described above, the work of adjusting the print density of the conventional rotary stencil printing apparatus cannot be easily performed by the user of the rotary stencil printing apparatus, and even if the print density is appropriate, the set-off does not occur. It has a drawback that it deteriorates or the durability of the stencil sheet is deteriorated. Therefore, the present situation is that no effective and appropriate means for adjusting print density and preventing set-off has been proposed in response to changes in printing conditions such as the temperature inside the rotary stencil printing machine and the printing speed.

[0005]

SUMMARY OF THE INVENTION In view of the above problems, the present invention always responds to changes in printing condition information such as temperature and printing speed in a rotary stencil printing machine automatically or only by input information from an operation panel. An object of the present invention is to provide a rotary stencil printing apparatus which can obtain a printed matter having the best print density and no set-off.

[0006]

In order to achieve the above object, the first invention of the present application is to supply ink from an inking roller to a stencil sheet wound around the outer periphery of a cylindrical perforated cylinder, and press a roller to the printing paper. In a rotary type stencil printing machine adapted to perform press printing by pressing, according to the printing condition information, the rotational speed of the cylindrical perforated plate cylinder rotated by the perforated plate cylinder drive unit and the ink application rotated by the inking drive unit. It is characterized in that the rotation speed ratio to the rotation speed of the roller is made variable.

In the second invention of the present application, the ink is supplied to the stencil sheet around the outer circumference of the cylindrical perforated cylinder by the inking roller, and the press roller is pressed against the printing paper to perform printing. The rotary stencil printing machine is characterized in that the gap between the inking roller and the doctor roller is variable according to the printing condition information.

[0008]

When the printing speed of the rotary stencil printing machine constructed as described above is low, the inside of the rotary stencil printing machine is at a high temperature, and when it is desired to suppress the printing density, the rotational speed of the perforated cylinder and the inking roller are set. By reducing the ratio of the number of rotations to the number of rotations, the shearing force between the inking roller and the doctor roller is reduced, the viscosity of the ink is kept high, the fluidity is suppressed, and the ink application amount is suppressed. Adjust the amount of ink applied to the appropriate amount.

On the other hand, when the printing speed is high or the rotary stencil printing machine has a low temperature, and the print density is desired to be increased, the rotation speed ratio of the rotation speed of the perforated plate cylinder to the rotation speed of the inking roller is increased. By increasing the shearing force between the inking roller and the doctor roller, the viscosity of the ink is kept low, the fluidity of the ink is increased, and the ink application amount is increased to apply the ink to the printing paper. Make the amount appropriate.

Further, the gap between the inking roller and the doctor roller is made larger when the print density is desired to be suppressed and is made smaller when the print density is desired to be increased. Adjust the force to make the amount of ink applied to the printing paper an appropriate amount in terms of print density and offset.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a perspective view of a rotary stencil printing machine showing an embodiment of the present invention, and FIG. 2 is a side view of a perforated body of a rotary stencil printing machine showing an embodiment of the present invention.

In FIG. 1, an operation panel 10 is provided at an appropriate position on the upper surface of the rotary stencil printing machine 0 of the present invention. In FIG. 2, on the outer peripheral surface of the cylindrical perforated cylinder 1,
The screen mesh 11 and the stencil sheet 2 are sequentially laminated. The perforated cylinder 1 includes a perforated cylinder driving unit 6 and a drive gear 1.
The ink is passed through the stencil sheet 2 wound around the perforated cylinder 1 and the screen mesh 11 which are rotatably driven by 2 to transfer an image to the printing paper 4.

FIG. 3 is a side view of the inking portion of the rotary stencil printing machine showing the embodiment of the present invention. Prior to this transfer operation, the ink I passes from the ink transport pipe 13 to the ink distributor 14. Then, the ink is supplied between the inking roller 3a and the doctor roller 8a, where a shearing force is applied to the ink. Since the inking roller 3a is rotated by the inking drive unit 7 which is separate from the perforated plate cylinder drive unit 6,
The rotation speed of the cylindrical perforated cylinder 1 and the rotation speed of the inking roller 3a can be freely changed by the rotation speed comparison setting means 15 by a control (not shown) described later depending on printing conditions.

In FIG. 3, the inking drive motor 7
By transmitting the drive to the inking roller drive gear 3b through the inking drive gear 7b of a, and further to the doctor roller gear 8b through the inking roller drive gear 3b, the inking roller 3a Also, the doctor roller 8a is driven.

The gap adjusting side plates 16 which are arranged to face each other at a predetermined interval are rotatably supported with a gap adjusting side plate fulcrum shaft 16b penetrating both side plates as a fulcrum. The gap adjusting side plate moving shaft 16a penetrating the both side plates 16 is configured to be movable in the horizontal direction by the gap adjusting drive unit 17 and the drive transmission rod 18.
Can rotate in the direction of the arrow with the fulcrum shaft 16b as the fulcrum. By moving the gap adjusting side plate 16 with the fulcrum shaft 16b as a fulcrum, the doctor roller shaft 8c also moves to the side plate 1.
It moves in the horizontal direction along a horizontal cut 20 (shown by a dotted line) provided on the plate 9. This is because the notch 16c of the gap adjusting side plate 16 into which the doctor roller shaft 8c is loosely fitted has an arc shape not centered on the gap adjusting side plate fulcrum shaft 16b, so that the gap adjusting side plate 16 uses the fulcrum shaft 16b as a fulcrum. The rotation causes the distance between the doctor roller shaft 8c and the gap adjusting side plate fulcrum shaft 16b to change, so that the inking roller 3a and the doctor roller 8
The gap 9 with a can be adjusted.

FIG. 4 is a front view of an inking section of a rotary stencil printing machine showing an embodiment of the present invention, and FIG. 5 is a gap adjusting drive section of a rotary stencil printing machine showing an embodiment of the present invention. It is an explanatory view of a main part. In FIG. 4 and FIG. 5, the drive transmission rod 18 is a screw rod integrally projecting upward from the central portion of the gap adjusting side plate moving shaft 16a in the longitudinal direction, and is a drive side screw protruding and rotating from the gap adjusting drive unit 17. Stick 1
It meshes with 7c. This drive side screw rod 17c is forward / reverse 2
By rotating in the direction, the drive transmission rod 18 advances and retreats in the horizontal direction indicated by the arrow together with the gap adjusting side plate moving shaft 16a. As a result, the side plate 16 is rotated about the shaft 16b in two forward and backward directions. The gap adjusting drive unit 17 includes a stepping motor 17b and a reduction gear 17c. 6 is an explanatory view of an operation panel of a rotary stencil printing machine showing an embodiment of the present invention, and FIG. 7 is an operation explanatory view of a rotary stencil printing machine showing an embodiment of the present invention. Figure 6
In FIG. 7, an operation panel 10 such as a flat keyboard is provided on the upper surface of the rotary stencil printing machine 0, and the number of prints, the numerical value of the printing condition information, the numerical value of the gap between the inking roller 3a and the doctor roller 8a, etc. are displayed. A numeric keypad 21 for setting, a temperature SW23 for manually inputting the temperature inside the rotary stencil printing machine automatically measured by a temperature sensor (not shown) and displayed on the display unit, a printing speed SW24 for setting a printing speed, an inking roller 3a. Gap SW25 for inputting the gap between the doctor roller 8a and the doctor roller 8a, density SW26 for inputting adjustment of print density, rotation for setting the rotational speed ratio of the rotational speed of the cylindrical perforated cylinder 1 to the rotational speed of the inking roller 3a. A display unit 22 is provided for displaying the numerical ratio SW 27, the number of printed sheets, the numerical values of printing condition information, and the like.

The control of each component described above is realized by a control unit such as a microcomputer (not shown). The following examples are carried out by changing the printing speed and the temperature inside the rotary stencil printing machine. Example 1) uses a plate cylinder of a digital stencil printing machine SS-955 manufactured by Ricoh Co., Ltd., controls the inking drive motor 7a, and controls the rotation speed of the inking roller 3a to the printing speed and the rotary stencil printing machine. It was changed according to the internal temperature. Then, printing is performed with an image area of 15%, and the print density (ID) is measured by Macbeth reflection densitometer R
The measurement was performed using D914, and the ink adhesion amount and set-off of the printed matter were also evaluated.

In the second embodiment, the inking drive motor 7a and the stepping motor 17b of the gap adjusting drive unit 17 are controlled by using a plate cylinder of a digital stencil printing machine SS-955 manufactured by Ricoh Co., Ltd. The rotation speed of the roller 3a and the gap between the inking roller 3a and the doctor roller 8a were changed depending on the printing speed. Then, printing was performed with an image area of 15%, the print density (ID) was measured using a reflection densitometer RD914 manufactured by Macbeth Co., and the ink adhesion amount and set-off of the printed matter were also evaluated.

In Comparative Example 1, a plate cylinder of a digital stencil printing machine SS-955 manufactured by Ricoh Co., Ltd. was used, and printing was simply performed with an image area of 15% without changing the printing speed and the spring pressure of the press roller 5. Print density (I.
D. ) Was measured using a reflection densitometer RD914 manufactured by Macbeth Co., Ltd., and the ink adhesion amount and set-off of the printed matter were also evaluated.

In Comparative Example 2), a plate cylinder of a digital stencil printer SS-955 manufactured by Ricoh Co., Ltd. was used, and a spring of the press roller 5 was used so that the printing density did not change due to the printing speed and the temperature inside the rotary stencil printing machine. The pressure was changed. Then, printing was performed with an image area of 15%, the print density (ID) was measured using a reflection densitometer RD914 manufactured by Macbeth Co., and the ink adhesion amount and set-off of the printed matter were also evaluated.

FIG. 8 shows the printing conditions (printing speed and temperature in the rotary stencil printing machine) of Examples 1 and 2 and Comparative Examples 1 and 2 and the perforated cylinder 1 under those conditions. The rotation speed ratio of the inking roller 3a and the gap 9 between the inking roller 3a and the doctor roller 8a are shown. FIG. 9 shows the results of the print density, the set-off evaluation, and the ink adhesion amount in a solid image when printing an image area of 15% under the conditions of the above-described example. As is clear from the result of FIG.
In the present invention, when the printing speed of the rotary stencil printing device is low or the inside of the rotary stencil printing device is at high temperature, and when it is desired to suppress the printing density, the rotation speed of the perforated cylinder and the rotation speed of the inking roller are rotated. By reducing the number ratio, the shearing force between the inking roller and the doctor roller is reduced, the viscosity of the ink is kept high, the fluidity is suppressed, and the ink application amount is suppressed, so that the ink application amount on the printing paper is reduced. It can be an appropriate amount.

On the other hand, when the printing speed is high or the rotary stencil printing machine has a low temperature, and when it is desired to increase the printing density, the rotation speed ratio between the rotation speed of the perforated plate cylinder and the rotation speed of the inking roller is increased. By increasing the shearing force between the inking roller and the doctor roller, keeping the viscosity of the ink low and increasing the fluidity of the ink, and increasing the ink application amount, the ink application amount on the printing paper can be increased. Can be an appropriate amount. Furthermore, if you want to reduce the printing density, increase the gap between the inking roller and the doctor roller, and if you want to increase the printing density, reduce the gap to reduce the shearing force between the inking roller and the doctor roller. The amount of ink applied to the printing paper can be adjusted to an appropriate amount in terms of printing density and offset.

[0023]

Since the present invention is constructed as described above, it has the following effects. The rotational speed ratio between the rotational speed of the perforated plate cylinder 1 and the rotational speed of the inking roller 3a inside the perforated plate cylinder 1 varies depending on the printing conditions. Further, the gap 9 between the inking roller 3a and the doctor roller 8a may be changed depending on the printing conditions. By changing it, the best printing density and no set-off will occur at all times, either automatically in response to changes in printing condition information such as the temperature inside the rotary stencil printer or printing speed, or only by input information from the operation panel. A printed matter was obtained.

[Brief description of drawings]

FIG. 1 is a perspective view of a rotary stencil printing machine showing an embodiment of the present invention.

FIG. 2 is a side longitudinal sectional view of a perforated body of a rotary stencil printing machine showing an embodiment of the present invention.

FIG. 3 is a side view of an inking section of a rotary stencil printing machine showing an embodiment of the present invention.

FIG. 4 is a front view of an inking section of a rotary stencil printing machine showing an embodiment of the present invention.

FIG. 5 is an explanatory diagram of a main portion of a gap adjusting drive unit of the rotary stencil printing machine showing the embodiment of the present invention.

FIG. 6 is an explanatory view of an operation panel of a rotary stencil printing machine showing an embodiment of the present invention.

FIG. 7 is an operation explanatory view of a rotary stencil printing machine showing an embodiment of the present invention.

FIG. 8 is a diagram summarizing printing conditions in a rotary stencil printing machine showing an embodiment of the present invention.

FIG. 9 is a diagram summarizing evaluation results of a rotary stencil printing machine showing an example of the present invention.

[Explanation of symbols]

I ... Ink, 0 ... Rotary type stencil printer, 1 ...
・ Multi-perforated cylinder, 2 ... Stencil base paper, 3a ... Inking roller, 3b ... Inking roller drive gear, 4.
..Printing paper, 5 ... Press roller, 6 ... Porous plate cylinder drive unit, 7 ... Inking drive unit, 7a ... Inking drive unit motor, 7b ... Inking drive unit gear , 8a ... Doctor roller, 8b ... Doctor roller gear, 8c ... Doctor roller shaft, 9 ... Gap, 10 ... Operation panel, 11 ... Screen mesh, 12 ... Drive gear , 13 ... Ink transfer pipe, 14 ... Ink distributor, 15 ... Rotational speed ratio setting means, 16 ... Gap adjusting side plate, 16a ...
・ Gap adjusting side plate moving shaft, 16b ... Gap adjusting side plate fulcrum shaft, 16c ... Gap adjusting side plate notch, 17
... Gap adjusting drive unit, 17a ... Gap adjusting drive unit stepping motor, 17b ... Gap adjusting drive unit reduction gear, 18 ... Drive transmission rod, 19
... Side plate, 20 ... Notch, 21 ... Numeric keypad, 2
2 ... Display unit, 23 ... Temperature SW, 24 ... Printing speed, 25 ... Gap SW, 26 ... Density SW,
27 ... Revolution speed ratio SW

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Koike 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh Co., Ltd. (72) Fumiaki Arai 1-3-6 Nakamagome, Ota-ku, Tokyo Shares Inside Ricoh Company (72) Kenichi Yamada 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company, Ltd.

Claims (2)

[Claims] 1. A rotary stencil printing machine in which ink is supplied from an inking roller to a stencil sheet wound around the outer periphery of a cylindrical perforated cylinder, and a press roller is pressed against the printing paper to perform printing. A rotary stencil printing machine comprising a control unit for varying a rotational speed ratio between the rotational speed of the cylindrical perforated cylinder and the rotational speed of the inking roller based on condition information. 2. A rotary stencil printing machine which supplies ink to a stencil sheet wrapped around the outer circumference of a cylindrical perforated cylinder by an inking roller and presses a press roller against the printing paper to perform printing. The rotary stencil printing machine according to claim 1, further comprising a control unit for varying the gap between the inking roller and the doctor roller.