JP4398656B2 - Printing drum and stencil printing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printing drum having an ink roller and an internal pressing member therein and a stencil printing apparatus using the printing drum.
[0002]
[Prior art]
In a stencil printing device, a master, which is a base paper, is wound around the outer peripheral surface of a porous printing drum, and then presses against the printing drum with a printing pressure member from outside to print the image formed on the master. The image printed on the printing paper may be rubbed only with the moss.
Therefore, as described in Patent Document 1, in order to push the ink from the inside of the printing drum to the outside of the ink, an inner pressing member called a nurse roller is provided inside the drum. The inner pressing member is provided so as to be selectively contactable with and separated from the outer peripheral surface of the ink roller disposed inside the drum and the inner peripheral surface of the drum, and is preferably in contact with the outer peripheral surface of the ink roller and the inner peripheral surface of the drum. By pressure contact, the ink adhered to the outer peripheral surface of the ink roller functions so as to be pushed out uniformly from the opening area of the printing drum toward the outer peripheral surface of the drum.
The inner pressing member is placed at a first position that comes into contact with the inner peripheral surface of the drum and the outer peripheral surface of the ink roller from the non-opening region of the printing drum, and is driven to rotate with the rotation of the printing drum so as to be suspended. It is configured.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-180026 [0004]
[Problems to be solved by the invention]
The inner pressing member rotates while occupying the first position from the non-opening area of the printing drum, but the rigidity is different between the opening area and the non-opening area of the printing drum. Even if the inner pressing member is brought into contact or pressure contact with the region, the inner peripheral surface of the drum may not be contacted uniformly, and a sufficient rotational force may not be obtained from the printing drum. For this reason, the inner pressing member rotates only after the rotation of the printing drum proceeds and enters the formation region of the aperture region where the rigidity is lower than the non-perforated region. Also, in the opening area, in the initial stage, the drum inner peripheral surface is contacted, preferably just pressed, so that it is difficult to sufficiently push the ink to the drum outer peripheral surface in the initial contact stage. May scrape off the necessary ink and rub the tip of the image immediately after printing.
An object of the present invention is to provide a printing drum capable of reliably extruding ink by an internal pressing member.
An object of the present invention is to provide a printing drum and a stencil printing apparatus that can reduce the rubbing of the leading edge of a printed image.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, an aperture region and a non-aperture region are provided on the peripheral surface, the ink roller is in contact with the inner peripheral surface, and the inner peripheral surface is in contact with the outer peripheral surface of the ink roller. A rotatable printing press drum that includes a rotatable internal pressing member that occupies a first position that contacts the inner peripheral surface and the outer peripheral surface of the ink roller at least when passing through the aperture region, In the non-aperture area, a strength reducing portion for reducing the drum circumferential surface strength is provided in the vicinity of the boundary between the aperture area on the front end side of the image located in the drum rotation direction and the non -aperture area. In addition, concave portions are provided on both side portions orthogonal to the drum rotation direction, and the strength reducing portions and the concave portions are formed independently . For this reason, the peripheral part of the printing drum in which the strength reducing part is formed is easily deformed, and the contact area with the internal pressing member is increased.
The strength reducing portion is a concave portion in which the thickness of the drum peripheral surface is partially reduced. Such a concave portion can be formed by cutting, but may be formed by an etching process or the like.
[0006]
If the concave portion is formed on the outer peripheral surface of the printing drum, the strength of the peripheral surface can be reduced. However, since a step is formed on the contact surface with the printing pressure member serving as the external pressing member, there is a concern that air may be mixed. For this reason, in order to eliminate the level | step difference by a recessed part, ensuring the ease of a deformation | transformation of a drum surrounding surface, you may provide a thin film member in a recessed part. When the thin film member is provided in the concave portion, that is, when the concave portion is filled, a concave portion having the same thickness as the depth of the concave portion or a plurality of thin films laminated to the same thickness as the concave portion is appropriately bonded or welded. Paste inside. As another form of the thin film member, it may be provided so as to cover the recess.
Although a concave portion may be formed on the inner peripheral surface of the printing drum, the internal pressing member may be damaged because the internal pressing member contacts. In order to prevent this, a thin film member may be provided in the recess as described above.
[0007]
Such a printing drum may be used in a stencil printing apparatus provided with a printing pressure member in which a master is wound around the outer circumferential surface and the outer circumferential surface is in contact with the printing paper via a printing paper.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 4 shows a configuration of a main part of a stencil printing apparatus provided with a plate cylinder 1 as a printing drum according to the present invention. In the figure, a plate cylinder 1 rotatably supported by a support shaft 1a has a stage portion and a clamper (not shown) on its outer peripheral surface 1a, and inside thereof is an ink supply means 2 and an internal pressing member. And a nurse roller 5. The plate cylinder 1 is rotationally driven in the direction of the arrow in the figure by a plate cylinder driving means (not shown). Below the plate cylinder 1, there is disposed a press roller 10 as a printing pressure member which is rocked by a rocking means (not shown) and whose outer circumferential surface is provided so as to be able to contact with and separate from the outer circumferential surface 1a of the plate cylinder 1. Has been. The press roller 10 presses the printing paper 40 against the plate cylinder 1 and transfers the print image onto the printing paper 40.
[0009]
As shown in FIG. 1, the plate cylinder 1 is composed of a metal porous support 101 and a mesh screen (not shown) wound around the outer peripheral surface thereof. FIG. 1 shows a developed state of the porous support 101. Although the porous support 101 is very thin, it is exaggerated in the drawings to clarify its features. The porous support 101 is formed with an open area 201 and a non-open area 202 that serve as an ink passage portion. The opening area 201 is formed so as to leave a non-opening area between the side portions 101a and 101b of the porous support 101 positioned on the axis line side of the plate cylinder 1 perpendicular to the rotation direction. Half edge portions 203 and 204 are formed between the opening area 201 and the side portions 101a and 101b, respectively. These half edge portions 203 and 204 reduce the rigidity in the vicinity of the side portions 101a and 101b so that the center portion learns the degree of deformation of the peripheral surface 1a of the plate cylinder 1 when pressed against the press roller 10. Is.
[0010]
Of the boundary portions 206 and 207 between the opening region 201 and the non-opening region 202, a half as a strength reduction portion that weakens the plate cylinder circumferential surface strength is provided in the vicinity of the boundary portion 206 as shown in FIG. An edge portion 205 is formed. The half edge portion 205 is formed to increase the contact area between the nurse roller 5 when the nurse roller 5 occupies the first position and contacts the inner peripheral surface 1b of the plate cylinder 1. FIG. 7 shows the pitch and arrangement of the holes formed in the aperture region 201. The holes are arranged in a hexagonal shape around one hole.
[0011]
As shown in FIGS. 3A and 3B, the half edges 203, 204, and 205 are formed as recesses in which the thickness of the porous support 101, which is the thickness of the drum peripheral surface, is reduced by etching or the like. ing. In this embodiment, when the porous support 101 is rolled up into a cylindrical shape, half edges 203 and 204 are formed on the surface of the porous support 101 on the inner peripheral surface 1b side of the plate cylinder 1 to thereby form the plate cylinder 1 A half edge 205 is formed on the surface of the porous support 101 on the outer peripheral picture 1a side. The half edge 205 is formed in the vicinity of the boundary 206 on the side where the leading edge of the image is located when a master (not shown) is wound around the plate cylinder 1. The vicinity of the boundary 206 is the vicinity of one end 201a of the hole area 201 located on the downstream side of the plate cylinder 1 in the rotation direction.
[0012]
As shown in FIG. 4, the ink supply means 2 is mainly composed of an ink roller 3 and a doctor roller 4. The ink roller 3 rotatably supported between the side plates 6 and 6 fixed to the spindle 1a is installed so that the outer peripheral surface thereof is close to the inner peripheral surface 1b of the plate cylinder 1, and an ink not shown in the drawing. The ink supplied from the supply pipe is supplied to the inner peripheral surface 1 b of the plate cylinder 1. The ink roller 3 is driven to rotate in the clockwise direction in the drawing in synchronism with the plate cylinder 1 by transmitting the rotational driving force from the plate cylinder driving unit by a driving force transmitting unit (not shown) such as a gear or a belt.
[0013]
The doctor roller 4 disposed in the vicinity of the ink roller 3 is rotatably supported between the side plates 6 and 6, and the rotational driving force from the plate cylinder driving unit is transmitted by a driving force transmission unit (not shown). The ink roller 3 is rotationally driven in the opposite direction. The doctor roller 4 is disposed so that a slight gap is formed between the outer peripheral surface of the doctor roller 4 and the outer peripheral surface 3 a of the ink roller 3, and forms a wedge-shaped ink reservoir 7 in the vicinity of the outer peripheral surface 3 a of the ink roller 3. ing. The ink in the ink reservoir 7 passes through the gap between the outer peripheral surface 3 a of the ink roller 3 and the outer peripheral surface 4 a of the doctor roller 4 to form an ink layer on the outer peripheral surface 3 a of the ink roller 3.
[0014]
The nurse roller 5 is disposed on the downstream side in the rotation direction of the plate cylinder 1 of the ink roller 3. The nurse roller 5 is rotatably supported at one end of the arms 8 and 8 at both ends of the support shaft 5a. The arm 8, which is a plate-like member that supports the nurse roller 5 at one end, is bent at the other end to form a receiving portion 8a. A long hole 8b is formed in the approximate center of the arm 8, and a long hole 8c is formed in the other end. Each arm 8, 8 has a long hole 8 b in a pin 9, 9 planted outward in each side plate 6, 6, and a bearing member 6 a, 6 a provided in each side plate 6, 6 (see FIG. The long holes 8c are respectively engaged with the support shafts 11 that are rotatably supported at 6 (see FIG. 4 as viewed from the right), so that they are supported on the outside of the side plates 6 and 6, respectively.
[0015]
Cam plates 12, 12 are attached to both ends of the support shaft 11, and a worm wheel 13 is attached to the middle. The disc-shaped cam plate 12 is fixed to the end of the support shaft 11 at a position eccentric from the center, and is disposed at a position where the outer peripheral surface of the large diameter portion can contact the receiving portion 8a. Yes. The arm 8 always keeps the receiving portion 8a on the cam plate by the biasing force of the tension coil spring 14 stretched between a bracket (not shown) provided on the back surface of the other end and a bracket (not shown) provided on the back surface of the side plate 6. 12 is drawn to the outer peripheral surface side.
[0016]
A stepping motor 15 fixed to each side plate 6, 6 by a mounting member (not shown) is disposed near the position where the worm wheel 13 is disposed between the side plates 6, 6. A worm 16 that meshes with the worm wheel 13 is attached to the output shaft of the stepping motor 15.
[0017]
The stepping motor 15 selectively positions the nurse roller 5 at the first position and the second position by rotating the cam plate 12 by its operation. When the large-diameter portion of the cam plate 12 is in contact with the receiving portion 8a, the nurse roller 5 has an outer peripheral surface 5b that resists the biasing force of the tension coil spring 14 and the inner peripheral surface 1b of the plate cylinder 1 and the ink roller. When the large-diameter portion of the cam plate 12 is separated from the receiving portion 8a, the outer peripheral surface 5b is urged by the biasing force of the tension coil spring 14 when the cam plate 12 is positioned at the second position shown in FIG. A predetermined biasing force of the tension coil spring 14 when the inner peripheral surface 1b of the plate cylinder 1 and the outer peripheral surface 3a of the ink roller 3 are brought into contact with and contact with each other and the minimum diameter portion of the cam plate 12 faces the receiving portion 8a. Thus, the plate cylinder 1 is positioned at the first position shown in FIG. 5, which is in pressure contact with the inner peripheral surface 1 b of the plate cylinder 1 and the outer peripheral surface 3 a of the ink roller 3. When the minimum diameter portion of the cam plate 12 faces the receiving portion 8a, a slight gap is set between them. That is, the outer circumferential surface 5 b of the nurse roller 5 can be brought into contact with and separated from the inner circumferential surface 1 b of the plate cylinder 1 and the outer circumferential surface 3 a of the ink roller 3.
[0018]
The operation time of the stepping motor 15 is controlled by a control means (not shown). In the present embodiment, at least a first position in contact with the inner peripheral surface 1b of the plate cylinder 1 and the outer peripheral surface 3a of the ink roller 3 when the hole area 201 of the plate cylinder 1 passes below the nurse roller 5 is occupied. So that its drive is controlled. When the hole area 201 passes below the nurse roller 5, the cam having a notch formed at an angle corresponding to the length of the non-hole area 202, that is, the angle can be integrally rotated with the plate cylinder 1. And a sensor is provided in the vicinity of the cam, and the non-notched portion of the cam may be detected by this sensor. Then, while the sensor detects the cam, the stepping motor 15 is driven to control the nurse roller 5 to occupy the first position. When the sensor stops detecting the cam, the driving of the stepping motor 15 is stopped. Then, the nurse roller 5 is controlled to occupy the second position.
[0019]
The drive control of the stepping motor 15 includes a post-leaving print mode key provided on an operation panel (not shown) for operating the nurse roller 5 when printing is performed after the stencil printing apparatus has been left for a long time, and the nurse roller 5. This is done by operating a number setting key for setting the number of times of operation. The control means (not shown) validates the ON signal from the sensor for the set number of times when the plate making start key (not shown) on the operation panel is pressed after the print mode key and the number setting key are operated after being left. While the ON signal from the sensor is input, the nurse roller 5 is positioned at the first position, and when the ON signal from the sensor is interrupted, the nurse roller 5 is positioned at the second position and set. Subtract the number of activations one by one.
[0020]
The operation of the stencil printing machine provided with the plate cylinder 1 having such a configuration will be described. The printing mode key after leaving on the operation panel (not shown) is operated by the operator to enter the printing mode after leaving, and the number setting key is operated to set the number of times of operation of the nurse roller 5, and then the plate making start key (not shown) is pressed. Then, the stepping motor 15 operates to position the nurse roller 5 at the first position. Prior to the operation of the stepping motor 15, an ink pump (not shown) is operated, so that the ink in the ink reservoir 7 is replenished to a position indicated by a broken line in FIG. As a result, the nurse roller 5 is positioned at the first position, so that a shortage of ink consumed in a larger amount than usual can be prevented. Thereafter, a plate discharging means (not shown) is operated to peel off the master of the previous plate from the outer peripheral surface 1a of the plate cylinder 1.
[0021]
At the time of this plate removal, the ink roller 3 and the doctor roller 4 are rotated and the nurse roller 5 is driven and rotated along with the rotation of the plate cylinder 1 in the clockwise direction in FIG. The nurse roller 5 is pressed against the outer peripheral surface 3 a of the ink roller 3 and the inner peripheral surface 1 b of the plate cylinder 1, thereby killing ink from the outer peripheral surface 3 a of the ink roller 3 to the inner peripheral surface 1 b of the plate cylinder 1. While being supplied, the old ink deteriorated by pressing the plate cylinder 1 is pushed into a master (not shown) wound around the outer peripheral surface 1 a of the plate cylinder 1 to be removed from the outer peripheral surface 1 a of the plate cylinder 1. At this time, since the nurse roller 5 is disposed downstream of the position where the ink roller 3 is disposed in the rotational direction of the plate cylinder 1, the nurse roller 5 is prevented from moving to the ink roller 3 side. No extra load is applied to No. 3, and stable ink supply is performed.
[0022]
When the ON signal from the sensor 18 is interrupted, the stepping motor 15 is actuated to position the nurse roller 5 at the second position, and the number of operations is decremented by one. Thereafter, the plate cylinder 1 is positioned at the home position, and the plate discharging operation is completed.
[0023]
After the plate removal, the plate cylinder 1 is driven to rotate, and a plate feeding operation and a plate-mounting operation are sequentially performed. Even during the plate feeding operation and the plate attaching operation, the nurse roller 5 is in pressure contact with the outer peripheral surface 3 a of the ink roller 3 and the inner peripheral surface 1 b of the plate cylinder 1 to kill ink from the outer peripheral surface 3 a of the ink roller 3. It is supplied to the inner peripheral surface 1 b of the plate cylinder 1.
[0024]
When a printing start key (not shown) is pressed after the printing operation, the printing cylinder 1 is driven to rotate and a printing operation is performed. Even during this printing operation, the nurse roller 5 is in pressure contact with the outer peripheral surface 3 a of the ink roller 3 and the inner peripheral surface 1 b of the plate cylinder 1, and the ink is killed from the outer peripheral surface 3 a of the ink roller 3. It supplies to the surrounding surface 1b. When the set number of operations is exhausted, the stepping motor 15 is operated and the nurse roller 5 is positioned at the second position.
[0025]
During the operation of the nurse roller 5, the contact state between the outer peripheral surface 5b of the nurse roller 5 and the inner peripheral surface 1b of the plate cylinder 1 was observed, and the following state was obtained. FIG. 8 is a development view of the plate cylinder 1 ′ using the porous support 101 ′ in which the half edge 205 is not formed. A state in which the nurse roller 5 is brought into contact with the plate cylinder 1 ′ and a state in which the nurse roller 5 is brought into contact with the plate cylinder 1 using the porous support body 101 on which the half edge 205 is formed. Is shown in FIG. 9A shows the contact state between the inner peripheral surface 1′b of the plate cylinder 1 ′ without the half edge 205 and the outer peripheral surface 5b of the nurse roller 5, and FIG. 9B shows the plate cylinder with the half edge 205. FIG. 1 shows the contact state between the inner peripheral surface 1b of 1 and the outer peripheral surface 5b of the nurse roller 5, respectively.
[0026]
The dimensions of the main members of the plate cylinders 1 and 1 'when these are observed are described. The main members of each plate cylinder have basically the same configuration and dimensions except for the presence or absence of the half edge 205.
[0027]
Diameter of plate cylinder 1, 1 ': 190mm
Ink roller 3 diameter: 49 mm
Doctor roller 4 diameter: 16 mm
Nurse roller 5 diameter: 25 mm
Thickness t of porous supports 101 and 101 ′: 0.2 mm
Each half edge depth t1: 0.1 mm
The diameter and pitch P of the holes formed in the opening area are 0.2 mm and 0.5 mm. When the nurse roller 5 occupies the first position under such dimensional conditions, the half-width is compared. The contact area with the inner peripheral surface 1b of the plate cylinder 1 provided with the edge 205 was increased. This is because by providing the half edge 205 to reduce the thickness of the porous support 101, the peripheral surface strength of the plate cylinder 1 is reduced, and the contact area between the inner peripheral surface 1b and the outer peripheral surface 5a of the nurse roller 5 is reduced. Seems to have grown.
[0028]
As the contact area between the two increases in this way, the nurse roller 5 is surely driven and rotated, and the ink can be reliably pushed out. Further, since the half edge 205 is formed in the vicinity of the boundary portion 206 located on the image leading end side in the opening area 201, the opening is made with the rotation of the plate cylinder 1 while the nurse roller 5 occupies the first position. Even when the region 201 passes, the contact state between the nurse roller 5 and the inner peripheral surface 1b of the plate cylinder 1 is maintained well before the aperture region 201 passes under the nurse roller 5, so that the leading edge of the image It is possible to reduce rubbing.
[0029]
When the half edge 205 is formed on the porous support 101, the contact area between the nurse roller 205 and the inner peripheral surface 1b of the plate cylinder 1 is maintained well, but a concave portion is formed on the outer peripheral surface 1a. There is a concern that air enters the recess when in contact with 10 and wrinkles are generated in the master wound around the outer peripheral surface 1a of the plate cylinder 1 by this air.
[0030]
Therefore, as shown in FIG. 10, when a resin thin film member 208 such as Mylar is provided in the half edge 205 serving as a recess so as to fill the recess, air does not flow into the recess, and the plate cylinder 1 While reducing the rigidity of the peripheral surface, it was possible to prevent wrinkles of the master due to air mixing. In this embodiment, a 0.1 mm thin film member 208 having the same thickness as the half edge 205 is pasted into the half edge 205 with a double-sided tape, and the step formed on the outer peripheral surface 1 a by the half edge 205 is eliminated.
[0031]
The thin film member 208 may be installed not in the half edge 205 but in a form so as to cover the entire half edge 205, but if it is covered in this way, air enters the half edge 205. Therefore, it is considered that the configuration in which the step is provided in the half edge 205 to eliminate the step is more practical.
[0032]
【The invention's effect】
According to the present invention, the strength reducing portion that weakens the drum peripheral surface strength is formed in the vicinity of the boundary portion between the opening area and the non-opening area of the printing drum, so that the printing drum having the strength reducing section is formed. The peripheral portion is easily deformed, and the contact area with the internal pressing member is increased. For this reason, an internal press member rotates reliably and can perform extrusion of an ink reliably.
According to the present invention, it is possible to reduce the rubbing of the leading edge of the printed image by using the printing drum that can reliably rotate the internal pressing member and reliably push out the ink.
[Brief description of the drawings]
FIG. 1 is a development view showing a configuration of a printing drum itself showing one embodiment of the present invention.
FIG. 2 is a side view schematically showing a contact position relationship between a printing drum and an internal pressing member.
3A is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3B is a cross-sectional view taken along line BB in FIG.
FIG. 4 is a partially enlarged sectional view showing an internal configuration of the printing drum and a second position of the internal pressing member.
FIG. 5 is a partial enlarged cross-sectional view showing an internal configuration of a printing drum and a first position of an internal pressing member.
FIG. 6 is a partial enlarged cross-sectional view showing an internal configuration of a printing drum and a configuration of an internal pressing member.
FIG. 7 is a partially enlarged view showing an example of arrangement of holes formed in the hole area.
FIG. 8 is a development view showing a configuration of a printing drum itself that does not have an intensity reduction unit.
9A is an enlarged view showing a contact state between the inner peripheral surface of the printing drum shown in FIG. 8 and the internal pressing member, and FIG. 9B is an inner peripheral surface of the printing drum according to the present invention shown in FIG. It is an enlarged view which shows a contact state with an internal press member.
FIG. 10 is a cross-sectional view of a strength reducing portion provided with a thin film member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Printing drum 1b Inner peripheral surface 3 Ink supply roller 3a Outer peripheral surface of ink roller 5 Internal pressing member 10 Printing pressure member 201 Opening area 202 Non-opening area
203, 204 Concave portion 205 Strength reducing portion 206 Near boundary portion 208 Thin film member

Claims (3)

An aperture region and a non-aperture region are provided on the peripheral surface, the ink roller contacting the inner peripheral surface, the inner peripheral surface and the outer peripheral surface of the ink roller can be contacted and separated, and at least the aperture A rotatable internal pressing member occupying a first position in contact with the inner peripheral surface and the outer peripheral surface of the ink roller when passing through an area, and a printing drum provided therein,
In the non-perforated region, a strength reducing portion is provided in the vicinity of the boundary between the perforated region on the leading end side of the image located in the drum rotation direction and the non-perforated region so that the drum peripheral surface is thinned to form a concave portion. ,
In the non-opening region, a recess is provided on each side perpendicular to the drum rotation direction,
The printing drum, wherein the strength reducing portion and the concave portion are independently formed . The printing drum according to claim 1.
A printing drum, characterized in that a thin film member is provided to fill the recess of the strength reducing portion . In a stencil printing apparatus comprising: a printing drum on which a master is wound on its outer peripheral surface; and a printing pressure member that comes into contact with the outer peripheral surface of the printing drum via a printing paper.
A stencil printing apparatus comprising the printing drum according to claim 1 or 2 as the printing drum .

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