JP2000218915A - Stencil printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely guide a recording medium to a conveying passage by releasing a form by a releasing pawl in the state that the form engages with the front edge of the recording medium conveyed on the outer periphery of a press roller and sticks to the outer periphery at least 45 deg. from an intersecting position of a holder from a plane passing axes of rotations of a plate cylinder and the roller. SOLUTION: A surface of a press roller 14 has an adhesive property. A printing gap 16 is formed by a plate cylinder 10 and the roller 14, and a form 20 is supplied from a sheet feeder 18 to the gap. The form 20 passing the gap 16 is released by a releasing pawl 22, and fed to a tail flow by a delivery unit 24. In the case that the roller 24 has a minimum diameter (20 mm), delivery of the form 20 at this time directs by the sum of an angle from a point of ending a contact length to a point of releasing the form and about 38 deg. of ending the length. An angle of 7 deg. corresponding to a perimeter obtained by considering capability of always adhering a form to the roller 14 side during printing of the form in the case of 20 mm of the diameter is added to become at least 45 deg. from the intersecting position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a stencil printing machine,
In particular, the present invention relates to a mechanism for reliably peeling a print medium from a press roller surface and stabilizing print quality.

[0002]

2. Description of the Related Art A stencil printing machine has a plate cylinder formed of an ink-permeable material and having a surface to which an original perforated in accordance with printing information is attached. At the time of printing, predetermined printing is executed by transferring the ink that has oozed to the surface from the inside of the plate cylinder through the holes of the original plate onto a recording medium.
Printing, that is, transfer of ink, is performed in a printing gap formed between the plate cylinder and a press roller that opposes the plate cylinder and sandwiches a recording medium such as paper. It is desirable that the recording medium be peeled off from the plate cylinder immediately after passing through the printing gap. This is to prevent show-through. With show-through, when the recording medium has been in contact with the plate cylinder for a long time, excess ink is transferred to the recording medium,
This is a phenomenon in which, when a printed recording medium is stacked on the recording medium, the ink that has not been completely dried is transferred to the back surface of the next recording medium.

[0003] Japanese Patent Application Laid-Open No. 62-142677 discloses an apparatus using a press roller having an adhesive surface so as to quickly peel off a recording medium from a plate cylinder after passing through a printing gap. The adhesive strength of the press roller surface is
By overcoming the viscosity of the ink on the surface of the plate cylinder, the recording medium is peeled off from the plate cylinder.

[0004]

However, according to the apparatus disclosed in the above publication, there is a problem that the recording medium may remain stuck to the press roller and cannot be sent to a predetermined conveyance path. . In addition, even if the recording medium is conveyed close to the plate cylinder even if the recording medium is peeled off from the press roller, and the front end of the recording medium has a high degree of curl toward the plate cylinder, the front end may contact the plate cylinder.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a stencil printing machine capable of peeling a recording medium from a plate cylinder immediately after passing through a printing gap and reliably leading the recording medium to a transport path. The purpose is to provide.

[0006]

In order to solve the above-mentioned problems, a stencil printing machine according to the present invention comprises a stencil sheet having predetermined perforations adhered to a surface thereof, and an ink supplied from the inside, the stencil sheet being supplied from the inside. A plate cylinder that oozes through the surface of the recording medium with the plate cylinder, a press roller that forms a nip portion that nips the recording medium with the plate cylinder and prints on the recording medium, and has an adhesive outer peripheral surface that nips the recording medium; Having a leading end disposed close to the outer peripheral surface, engaging with a front edge of the recording medium adhered to the outer peripheral surface and conveyed, and with the rotation of the press roller, the plate cylinder and the A state in which the recording medium is stuck to the outer peripheral surface at least 45 degrees from the intersection of the plane passing through each rotation center axis of the press roller and the sandwiching portion, and is arranged at a position where the recording medium is peeled from the outer peripheral surface And peeled-off nails.

[0007]

Embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings. FIG. 1 shows a main part of a stencil printing machine according to the present embodiment.
The plate cylinder 10 is a cylinder having ink permeability and has an ink supply roller 1 for supplying ink to an inner surface thereof.
2 are arranged. A press roller 14 is arranged so as to be in contact with the outer periphery of the plate cylinder 10 at a position where the ink supply roller 12 is arranged. The surface of the press roller 14 has adhesiveness. A printing gap 16 is formed by the plate cylinder 10 and the press roller 14, and a paper 20 as a recording medium is supplied from a paper feeding device 18 to the printing gap 16. The paper 20 that has passed through the printing gap 16 is peeled off from the press roller 14 by a peeling claw 22, and is sent downstream by a paper discharging device 24. The paper discharging device 24 includes a transport belt 26 that transports the paper 20 on which printing has been completed, and a transport belt 26 that transports the paper 20.
And a suction fan 28 for sucking air. Due to the negative pressure generated by the suction fan 28, the paper 20 is sucked onto the transport belt 26.

FIG. 2 is a view of the periphery of the printing gap 16 from the paper transport direction. In the printing area 30 of the plate cylinder indicated by double hatching in the figure, a perforation according to the content of printing is made, and ink permeates from the inside of the plate cylinder 10 to the surface through this hole. The print area 30 is slightly smaller than the width of the paper 20. The surface of the press roller 14 (indicated by hatching in the figure) has an adhesive property in a width substantially equal to the print area 30. The adhesive strength is 7 in this embodiment.
It is about g / cm ² , but it is desirable to set it appropriately depending on the viscosity of the ink used. Further, the adhesive surface may be provided on a part in the width direction (hatched part in the figure) like the press roller 32 shown in FIG. As the position of the adhesive surface, it is preferable to select a contact position for any paper size based on the paper size that may be used. Similarly, for the disposition of the peeling claw 22 in the direction orthogonal to the sheet conveying direction, it is preferable to select a position that comes into contact with any sheet of a size that may be used. FIG. 4 is a partial cross-sectional view of the press roller 32 partially having adhesiveness. The press roller 32 is provided with an adhesive ring 36 made of an adhesive material and a non-adhesive ring 38 made of a normal rubber material. The outer periphery of the adhesive ring 36 has a thickness dimension D protruding around by a dimension C. In this case, the gap dimensions A,
The management of the width dimension E of B and the non-adhesive ring 36 and the dimensions C and D described above are important in flattening the surface of the press roller 32 during printing. In particular, dimensions A, B,
C is important, such as the hardness of the material of the adhesive ring 36,
Thickness D, width E, plate cylinder 10 and press roller 1
In connection with the pressing force of No. 4, it needs to be managed. When the material of the adhesive ring 36 and the hardness of the other parts are the same, the dimensions A, B, and C are preferably set to zero. As the allowable range, the dimensions A and B are 0 to 0.5 mm, and the dimension C is -0.2 to 0.2 mm, which is an appropriate range that does not affect the print quality.

The position where the peeling claw 22 is arranged will be described with reference to FIG. FIG. 5 shows a diameter of 20, 30, 70 mm.
Are shown in the drawing. These three diameters were determined as follows. 20mm diameter
Is determined mainly from the rigidity of the shaft of the press roller, the deterioration of the elastic layer provided on the surface due to fatigue, and the paper transportability. That is, regarding the rigidity, the shaft of the press roller bends due to the contact pressure with the plate cylinder, but the diameter of the shaft is in a range where the warp does not cause a decrease in print quality (such as a thin center in the width direction). . In addition, the number of repetitions of stress generated by the elastic layer is pressed against the plate cylinder,
The smaller the diameter, the greater the number, and the shorter the deterioration. The diameter of the shaft is determined so that this deterioration does not cause a problem in practical use. Further, the contact area required for transporting the sheet is also taken into consideration. The value of the diameter is 20 mm
Is empirically the value estimated to be the smallest value that satisfies these. The diameter of 70 mm is determined in consideration of the swing of the press roller during printing and non-printing, and the material cost that increases and increases. That is, the weight is such that it can swing, and the cost such as the material cost is determined to be within a predetermined range. The value of the diameter 7
0 mm is the largest value that satisfies these empirically. The diameter of 30 mm is an intermediate value between the above values.

On the other hand, the diameter of the plate cylinder 10 is 155 mm, and the diameter of the ink supply roller 12 is 50 mm. When the plate cylinder 10 and the press roller 14 are pressed against each other, the press roller 1
4 is compressed. The amount of compression is proportional to the pressing force. If the amount of compression is small, the amount of transferred ink is small, and the printing becomes thin. If the amount of compression is large, the ink is excessively transferred, and a maximum of about 2 mm is preferable. In the figure, the position compressed by about 2 mm is indicated by a two-dot chain line. When the press roller 14 is compressed by about 2 mm in this way, the plate cylinder 10
And the length of the contact between the press roller 14 (hereinafter referred to as the contact length) is affected by the rubber hardness and the diameter of the press roller,
In this range, the ink is transferred to the paper. If it is 6 mm or less, poor conveyance is likely to occur, and if it is 20 mm or more, bleeding tends to occur. The tangential direction Q of the press roller 14 at the rear end point of the rear end of the position compressed by 2 mm is about 38 ° downward with respect to the sheet supply direction P when the diameter of the press roller 14 is 20 mm. , Also with a diameter of 3
In the case of 0 mm, it is about 35 °, and in the case of 70 mm, it is about 23 °.

The paper 20 is conveyed to the press roller 14 from the point where the contact length between the plate cylinder 10 and the press roller 14 is completed to the point where the paper 20 is peeled off by the peeling claw 22 while being adhered to the press roller 14. At this time, in the case of the smallest diameter (20 mm) of the press roller 14, the discharge direction of the sheet 20 is obtained by adding an angle from the point at which the contact length ends to the point at which the sheet is peeled to about 38 ° at which the contact length ends. It will be. This angle is determined in consideration of the fact that the adhesiveness of the surface of the press roller 14 allows the sheet to always adhere to the press roller 14 during printing. This angle is, specifically, the length on the circumference of the press roller,
The angle is set to about 1.2 mm. If the diameter is 20mm, the angle corresponding to this circumference is about 7 °
Becomes If the angle 7 ° corresponding to the length for keeping the sheet adhered is added to the central angle 38 ° corresponding to the contact length between the press roller 14 and the plate cylinder 10, it becomes 45 °.
If the peeling claw 22 is arranged in a range exceeding this angle,
The state in which the sheet 20 is stuck to the press roller 14 side is maintained, and the sheet 20 is reliably transported to the position of the peeling claw 22.

In other words, the position of the peeling claw 22 is, in other words, a plane R connecting the plate cylinder 10 and the center of the press roller 14.
The peeling claw 22 is arranged so that it is stuck to the press roller 14 at least 45 ° from the intersection position between the contact claw and the contact length portion.

If the diameter of the press roller 14 is 70 mm, the position of the peeling claw 22 may be within a range of a little less than 67 ° from the plane R. However, if the diameter of the press roller is large, the paper after printing and the plate cylinder 10 are close to each other, and in consideration of the case where the leading edge of the paper flies upward or the paper is peeled off from the adhesive portion, the press Similarly to the case where the diameter of the roller 14 is 20 mm, it is preferable to arrange the roller 14 so as to stick at least 45 °.

FIG. 6 shows another embodiment.
Inside the plate cylinder 50, an intermediate press roller 52 is arranged, and the plate cylinder 5
No. 0 is pressed to make the plate cylinder 50 project outward.
A press cylinder 54 corresponding to the press roller 14 of the embodiment of FIG.
The paper is nipped in a printing gap formed between the press cylinder 54 and the press cylinder 54. An adhesive film 5 is provided on the outer peripheral surface of the press cylinder 54.
6 is nervously wound. Both ends of the adhesive film are fixed by mounting members 58 and 60. The leading edge of the paper 62 is initially held by the clamp 64 and enters the printing gap. After passing through the printing gap, the clamp 6 is located immediately before the peeling nail 66.
4 is opened, and the sheet 62 is peeled off from the surface of the adhesive film 56 in accordance with the rotation of the press cylinder 54. The position of the peeling claw 66 is preferably at least 45 ° from the intersection of the plane passing through the center of the plate cylinder 50 and the center of the press cylinder 54 with the contact length, as in the above-described embodiment. It is. In the case of the present embodiment,
The adhesive film 56 can be replaced, and the film whose adhesiveness has been reduced can be replaced. The press cylinder as in the present embodiment needs to have the same diameter as the plate cylinder. This is because it is necessary to prevent the clamping means 64 from abutting the base paper on the plate cylinder.

FIGS. 7 and 8 show still another embodiment. The plate cylinder 70 and the ink supply roller 72 are arranged as shown in FIG.
Has the same configuration as the plate cylinder 50 and the ink supply roller 52 of the embodiment shown in FIG. The outer peripheral surface of the press roller 74 has adhesiveness. The press roller 74 is provided with a lever 76.
Is rotatably supported at one end. The lever 76 is swingably supported by a shaft 78 and a press roller 74.
An urging force is applied to the end opposite to the end supporting the press roller 74 by the spring 80 so as to direct the press roller 74 toward the plate cylinder 70. The drive roller (not shown) controls the press roller 74 to move toward and away from the plate cylinder 70. The paper 82 is peeled off from the surface of the press roller 74 by a peeling claw 84 provided integrally with the lever 76. In the case of the present embodiment, the relative position between the press roller 74 and the peeling claw 84 does not change even if the press roller 74 is moved in order to move toward or away from the plate cylinder 70. Therefore, the paper 82 is stably pressed by the press roller 7.
4 can be peeled off.

FIG. 9 shows an example of the configuration of a peeling claw when the press roller has a flexible cylinder. The press roller 90 has a flexible cylinder 92, and has an adhesive portion 94 on the surface thereof. Peeling nail 96
Is provided integrally with a lever 100 that swings about a shaft 98. A follow-up roller 102 is provided at an end of the lever 100 on the side where the peeling claw 96 is provided, and a spring 104 for urging the follow-up roller 102 toward the cylinder 92 is provided at the other end.
Is connected. Since the follower roller 102 follows the surface of the deformable cylinder 92 of the press roller 90, the relative position between the peeling claw 96 and the surface of the press roller 92 is always maintained in a constant relationship.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a main part of the present embodiment.

FIG. 2 is a side view showing a part of the embodiment of FIG. 1;

FIG. 3 is a diagram showing an example of an arrangement of a portion having adhesiveness different from that of FIG. 2;

FIG. 4 is a view for explaining detailed dimensions of an adhesive portion of FIG. 3;

FIG. 5 is a diagram for explaining an appropriate arrangement of a peeling nail.

FIG. 6 is a diagram showing a configuration of a main part of another embodiment.

FIG. 7 is a diagram showing a configuration of a main part of still another embodiment.

FIG. 8 is a side view showing a part of the embodiment of FIG. 7;

FIG. 9 is a diagram showing another configuration example of the peeling nail.

[Explanation of symbols]

10 plate cylinder, 14, 32 press roller, 16 printing gap, 20 sheets, 22, 66, 84, 96 peeling claw.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shun Omoto 20-10 Nakayoshida, Shizuoka City, Shizuoka Prefecture Star Precision Co., Ltd. F-term (reference) 3F053 AA22

Claims (1)

[Claims] 1. A plate cylinder on which a predetermined perforated base paper is affixed to a surface thereof, and an ink supplied from inside is extruded from a hole of the base paper to the surface, and a recording medium is sandwiched together with the plate cylinder. A press roller having an adhesive on an outer peripheral surface for sandwiching the recording medium, and having a tip disposed close to the outer peripheral surface, and being attached to the outer peripheral surface to convey the recording medium; Engaged with the leading edge of the recording medium,
With the rotation of the press roller, at least 45 degrees from the intersection of the plane passing through the rotation axis of the plate cylinder and the rotation axis of the press roller and the sandwiching portion is stuck to the outer peripheral surface at least 45 degrees, A stencil printer having a peeling claw arranged at a position where the recording medium is peeled off from the outer peripheral surface.