JP2000335072A - Printing pressure regulating mechanism for stencil printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong a using lifetime by broadening selection of a tensile coil spring for giving a printing pressure to a press roller, and suppressing a dynamic torque applied to the spring. SOLUTION: The printing pressure regulating mechanism for a stencil printer rotates a plate cylinder 14 wound with a stencil base sheet supplied with ink to an inner periphery and engraved on its outer periphery, brings a press roller 18 to an outer periphery of a stencil base sheet, conveys a printing sheet, and prints a stencil in a pressing type. The mechanism comprises an adjusting screw 53 for locking one end of a tensile coil spring 56 for giving a pressure contact force to the roller 18, a varying means for axially moving the screw 53 by rotation of a nut member 54 engaged with the screw 53 to vary a mounting length of the spring 56 to vary the spring force, and a rotation inhibiting member 66 provided to move in the moving direction of the screw 3 to a site not relative to the movement of the screw 53 so as to be locked to the screw 53.

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 printing pressure adjusting mechanism for adjusting the density during printing.

[0002]

2. Description of the Related Art In general, a stencil sheet made of stencil is wound around an outer peripheral surface of a cylindrical plate cylinder having ink supplied to an inner peripheral surface thereof.
2. Description of the Related Art A stencil printing machine is known which performs a stencil printing in a pressing manner by rotating a plate cylinder and pressing a printing sheet against an outer peripheral surface of a stencil sheet with a press roller. In this type of stencil printing press, the press roller can be moved substantially vertically between a retracted position separated from the outer peripheral surface of the plate cylinder by a driving device and a press-contact position pressed against the outer peripheral surface of the plate cylinder. It has been.

As shown in FIG. 7, the driving device of the press roller 118 has a link member which moves substantially up and down by a press cam 162 which rotates in synchronization with the rotation of the plate cylinder 114. The link member includes a first link member 148 in the form of a long plate that is involved in the approximately vertical movement of the press roller 118, and a second link member 149 in the form of a long plate that is involved in the up and down movement of the press cam 162. First link member 1
48 and the second link member 149
8, a pair of long holes 150 formed along the longitudinal direction;
Combination with a pair of pins 151 formed along the longitudinal direction of the second link member 149 allows the second link member 149 to slide in the longitudinal direction (the direction in which the link member moves up and down). The first link member 148 and the second link member 149 are connected via a tension coil spring 156.

The tension coil spring 156 has one end fixed to the first link member 148 side and the other end fixed to one (lower in FIG. 6) pin 151 of the second link member 149. The fixing of the one end of the extension coil spring 156 to the first link member 148 side is configured as follows.

As shown in FIG. 7, the first link member 148
A flange piece 152 is formed by bending at the lower end of the. This flange piece 152 has a rod-shaped adjusting screw 1
53 penetrates movably in the longitudinal direction of the first link member 148 (direction in which the link member moves up and down substantially). On the lower end side of the adjusting screw 153 penetrating the flange piece 152,
The nut member 154 is screwed. Extension coil spring 15
One end of 6 is inserted and locked at the upper end of the adjusting screw 153. Therefore, although the adjusting screw 153 is pulled upward by the spring force of the extension coil spring 156, the upward movement is regulated by the nut member 154 screwed through the flange piece 152. Thereby, one end of the extension coil spring 156 is fixed to the first link member 148 side. The tension coil spring 156 stops the rotation of the adjusting screw 153.

An external gear 155 coaxial with the adjusting screw 153 is provided on a nut member 154 screwed to the adjusting screw 153. The external gear 155 is provided with the flange piece 15.
Output shaft 165 of the pulse motor 164 attached to the motor 2
And the driving gear 163 fixed to the gear.

In the driving device for the press roller 118,
When the press cam 162 rotates with the rotation of the plate cylinder 114, the second link member 149 reciprocates substantially vertically. The reciprocating motion of the second link member 149 is transmitted to the first link member 148 via the extension coil spring 156. When the first link member 148 reciprocates, the press roller 118 swings substantially vertically and moves between the retracted position and the pressed position.

[0008] The movement of the press roller 118 to the pressure contact position is such that the upward movement of the second link member 149 imparts a spring force to the extension coil spring 156, and the first link member 1
48. Then, the press roller 118 is pressed against the outer peripheral surface (stencil sheet) of the plate cylinder 114 while sandwiching the printing paper. The second link member 149 further raises the press roller 118 from a position where the press roller 118 is pressed against the outer peripheral surface of the plate cylinder 114 by further rotation of the press cam 162. Therefore, the spring force due to the extension of the extension coil spring 156 when the second link member 149 is further pulled up is transmitted to the press roller 118 via the first link member 148. That is, the press roller 118 is given a pressing force (printing pressure) to be pressed against the outer peripheral surface (stencil sheet) of the plate cylinder 114 across the printing paper by the spring force of the extension of the tension coil spring 156. .

Further, the pressing force of the press roller 118 can be changed by the above configuration. When changing the pressure contact force, the pulse motor 164 is driven to rotate the drive gear 163. The rotation of the driving gear 163 is controlled by the nut member 154.
Is transmitted to When the nut member 154 rotates, the adjusting screw 153 screwed with the nut member 154 moves in the axial direction with respect to the first link member 148, and the first link member 1 of the adjusting screw 153 is rotated.
The axial position with respect to 48 changes. This allows
The position of one end of the tension coil spring 156 locked by the adjusting screw 153 is displaced, the length of the tension coil spring 156 changes, and the spring force for pressing the press roller 118 against the outer peripheral surface of the plate cylinder 114 (stencil sheet). , That is, the pressing force (printing pressure)
Is variable. As described above, the driving device of the press roller 118 has the printing pressure adjustment mechanism that varies the pressing force of the press roller 118 against the plate cylinder.

[0010]

However, in the printing pressure adjusting mechanism of the conventional stencil printing machine described above, one end of the tension coil spring 156 is inserted into the upper end of the adjustment screw 153, and the adjustment screw 153 is rotated by the tension coil spring 156. Due to the stopped configuration, there were the following problems.

First, the dynamic torque at which the adjusting screw 153 moves in the axial direction by the rotation of the nut member 154 must be smaller than the torsional torque of the extension coil spring 156. The reason is that when the dynamic torque is larger than the torsional torque, the adjustment screw 153 does not rotate due to the rotation of the nut member 154, and the tension coil spring 156 rotates in the torsional direction or the opposite direction. Breaking occurs. Therefore, the tension coil spring 15 used
No. 6 is limited to those having a torsional torque larger than the dynamic torque applied to the adjusting screw 153, and there is a problem that the degree of freedom in design is reduced.

Even if the dynamic torque applied to the adjusting screw 153 is smaller than the torsional torque of the tension coil spring 156, the tension coil spring 1
56, the tension coil spring 15
The load on 6 may increase over time, causing spring breakage.

The dynamic torque applied to the adjusting screw 153 varies depending on the wear of the screw thread, the lubrication state, and the like. Therefore, the extension coil spring 156 having a large torsional torque is used.
Although there is no problem in the initial stage of assembling, the dynamic torque increases during use, which also causes a problem that spring breakage occurs.

Further, since the dynamic torque of the adjusting screw 153 is applied to the tension coil spring 156 as described above, the adjusting screw 1
At the time of stopping 53, the position of the extension coil spring 156 is not determined. That is, even if the adjusting screw 153 stops at the same position, the extension coil spring 156 does not become the same length. Therefore, the extension coil spring 156 having a particularly large spring constant is used. In this case, there is a disadvantage that the printing pressure varies, and a desired printing pressure cannot be obtained.

[0015] In order to solve the above-mentioned problems, the present invention provides a stencil in which the selection of the extension coil spring can be broadened, and the dynamic torque applied to the extension coil spring can be suppressed to extend the service life of the extension coil spring. It is an object of the present invention to provide a printing pressure adjusting mechanism for a printing press.

[0016]

According to a first aspect of the present invention, there is provided a stencil printing press having a printing pressure adjusting mechanism according to the present invention, wherein an ink is supplied to an inner peripheral surface of an outer peripheral surface of a plate cylinder. To wind the stencil sheet made, and rotate the plate cylinder, press the press roller against the outer peripheral surface of the stencil sheet to convey the printing paper, in order to perform stencil printing on the printing paper by pressing. A driving device that moves between a press-contact position for pressing the press roller against the outer peripheral surface of the plate cylinder at a predetermined timing synchronized with the rotation of the plate cylinder, and a retracted position for separating the press roller from the outer peripheral surface of the plate cylinder. In the printing pressure adjusting mechanism of a stencil printing machine having an adjusting screw for locking one end of a tension coil spring supporting the press roller when the press roller is moved, a nut screwed to the adjusting screw. Variable means for changing the mounting length of the tension coil spring to vary the spring force by moving the adjusting screw in the axial direction when the nut member is rotated; and adjusting the adjusting screw. A rotation preventing member provided at a portion not involved in the movement of the adjustment screw so as to lock the rotation of the adjustment screw, so as to prevent the adjustment screw from rotating along with the rotation of the nut member.

According to a second aspect of the present invention, in the printing pressure adjusting mechanism for a stencil printing machine according to the first aspect, the detent member has one end of the tension coil spring. The adjusting screw is provided so as to be moved in a moving direction of the adjusting screw with respect to a portion not involved in the movement of the adjusting screw.

According to a third aspect of the present invention, in the printing pressure adjusting mechanism for a stencil printing machine according to the first aspect, the detent member is engaged with the adjusting screw, and The one end of the tension coil spring is locked so as to move in a moving direction of the adjustment screw with respect to a portion not involved in the movement of the adjustment screw.

A printing pressure adjusting mechanism for a stencil printing machine according to a fourth aspect of the present invention is the printing pressure adjusting mechanism for a stencil printing machine according to any one of the first to third aspects, wherein the detent member is provided with the adjusting member. It is configured to move in a movement direction of the adjustment screw with respect to a part not involved in the movement of the screw, and has a detection piece according to a position detection sensor for detecting a movement position of the adjustment screw. I do.

[0020]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows a stencil printing machine having a stencil making function as an example of a stencil printing machine according to the present invention. The stencil printing machine includes a document reading unit 1, a stencil making unit 2, and a printing unit 3.

The document reading section 1 is an image scanner, and has a line image sensor 4 for reading an image of a document conveyed in the sub-scanning direction, and a document feed roller 5. The document reading unit 1 is not limited to the above configuration, and may be configured to read the image of the document by moving the line image sensor 4 in the sub-scanning direction with respect to the fixed document. As described above, the document reading unit 1 reads the image of the document by relatively moving the document and the line image sensor 4.

The plate making section 2 includes a base paper roll section 6, a thermal head 7 composed of a plurality of point heating elements arranged in a horizontal line, base paper feed rollers 8, 9, a base paper guide roller 10, And a base paper cutter 13. Then, the plurality of dot heating elements of the thermal head 7 selectively and individually generate heat, thereby performing the heat-sensitive perforation stencil making on the heat-sensitive stencil sheet M in a dot matrix manner.
As a result, the stencil sheet M after stencil making is cut.

The printing unit 3 includes a porous plate-shaped ink-permeable cylindrical plate cylinder 14 made of an ink-permeable material such as a porous metal plate or a mesh structure, and a squeegee disposed inside the plate cylinder 14. An ink supply device 17 including a roller 15 and a doctor roller 16 and a press roller 18 are provided. The plate cylinder 14 is rotationally driven in a counterclockwise direction in FIG. 1 around its own central axis by a rotational driving means (not shown). Further, the plate cylinder 14 is provided with a clamp portion 14a for clamping an end of the stencil sheet M. And
The stencil sheet M is wound around the outer peripheral surface of the stencil sheet M while being rotated while clamping the stencil sheet M by the clamp portion 14a.

A paper feed unit 19 is provided on one side of the printing unit 3, and a paper discharge unit 20 is provided on the other side of the printing unit 3.

The paper supply unit 19 includes a paper supply table 21 on which the print papers P are stacked and stacked, a pickup roller 22 for taking out the print papers P one by one from the paper supply table 21, and a print cylinder P with the plate cylinder 14. It has a paper feed timing roller 23 for feeding between the press roller 18.

The paper discharge unit 20 includes a stripping claw 24 for peeling the printing paper P from the plate cylinder 14, a paper discharge feed belt unit 25,
And a discharge tray 26 on which printed printing papers P are stacked.

On one side of the printing unit 3, a stencil sheet M used is peeled off from the plate cylinder 14 and a stencil discharge roller 28 for feeding the stencil sheet M into a stencil discharge box 27.
9 are provided.

In the stencil printing machine having the above-described configuration, a predetermined color printing ink is supplied to the inner peripheral surface of the plate cylinder 14 by the ink supply device 17. The plate cylinder 14 is rotationally driven counterclockwise in the figure around its own central axis by a rotational driving means (not shown). The printing paper P is moved from the left to the right in FIG. 1 by the paper feed timing roller 23 at a predetermined timing in synchronization with the rotation of the plate cylinder 14, and is moved between the plate cylinder 14 and the press roller 18. Supplied to Then, the printing paper P is pressed against the stencil sheet M wound around the outer peripheral surface of the plate cylinder 14 by the press roller 18 so that stencil printing with a predetermined color printing ink is performed on the printing paper P. Done.

Hereinafter, a driving device of the press roller 18 according to the stencil printing machine having the above-described configuration will be described. FIG.
Indicates a driving device of the press roller 18. As shown in FIG. 2, the press roller 18 extends in the axial direction of the plate cylinder 14 and is supported by a bracket 40 so as to be rotatable around its own central axis. The bracket 40 is fixedly mounted on a press shaft 41 rotatably supported by a frame of a stencil printing machine (not shown), which is a fixed member. Thereby, the press roller 18 can be swingably displaced about the press shaft 41 in a substantially vertical direction in FIG.
Is movable between a retracted position separated from the outer peripheral surface of the plate cylinder and a pressure contact position pressed against the outer peripheral surface of the plate cylinder 14.

The press shaft 41 has a press drive lever 42
Is fixedly mounted. Therefore, the bracket 40 supporting the press roller 18 and the press drive lever 42
The two rock about each other about the press shaft 41.

The press shaft 41 is connected to a press drive plate 43.
Is rotatably supported. A hook member 45 is rotatably attached to one rotation end of the press driving plate 43 by a pivot 44. The rotation of the hook member 45 is driven by a solenoid 46 mounted on the press drive plate 43. The hook member 45 rotated by the driving of the solenoid 46 selectively engages with the press drive lever 42 to drive and connect the press drive lever 42 (the bracket 40) and the press drive plate 43 to each other.

At the other rotating end of the press drive plate 43,
A link member is connected. This link member includes a first link member 48 and a second link member 49 formed in a long plate shape. One end of the first link member 48 in the longitudinal direction (the lower end in FIG. 2) is pivotally connected to the other rotating end of the press drive plate 43 via a pivot 47. The other end of the first link member 48 (the upper end in FIG. 2)
Are formed with two long holes 50 extending in the longitudinal direction.

The second link member 49 has two pins 51 protruding from the plate surface at one end (the lower end in FIG. 2) in the longitudinal direction thereof. The second link member 49 connects each pin 51 to each slot 50 of the first link member 48.
, Respectively.

Thus, the first link member 48 and the second link member 49 are displaceably connected to each other so as to expand and contract in the longitudinal direction, that is, in substantially the vertical direction in FIG. .

Further, one end of the first link member 48 (FIG. 2)
A flange piece 52 is provided at the middle lower end).
The bent flange piece 52 is bent at substantially 90 degrees with respect to the plate surface of the first link member 48. A rod-shaped adjustment screw 53 is loosely inserted into the flange piece 52.
The adjustment screw 53 is movable in the direction of displacement between the first link member 48 and the second link member 49 with respect to the flange piece 52. A nut member 54 is screwed into a lower end portion where the adjusting screw 53 is loosely inserted into the flange piece 52. An outer gear 55 in the form of a spur gear having the same axis as the adjusting screw 53 is integrally provided on an outer peripheral portion of the nut member 54.

One end of a tension coil spring 56 is inserted and locked at the upper end where the adjusting screw 53 is loosely inserted into the flange piece 52. Further, the other end of the extension coil spring 56 is connected to the pin 5 inserted in the long hole 50 of the first link member 48.
It is locked to one of the ones. Thereby, the adjusting screw 53
Is pulled upward by the spring force of the extension coil spring 56. Then, the nut member 54 screwed to the lower end of the adjusting screw 53 comes into contact with the flange piece 52. as a result,
The extension coil spring 56 pulls the first link member 48 and the second link member 49 relatively in the longitudinal direction, and applies an urging force to minimize the longitudinal displacement of the first link member 48 and the second link member 49 to the shortest length. Occurs.

The other end of the second link member 49 (FIG. 2)
The middle upper end) is pivotally connected to a tip end of a cam lever 58 by a pivot 57. The cam lever 58 is connected to the support shaft 5.
Reference numeral 9 denotes a rotatably supported frame of a stencil printing machine (not shown). In addition, the cam lever 58 rotatably supports the cam follower roller 60 by a pivot 57 that pivotally connects the second link member 49. The cam follower roller 60 is a press cam 62 mounted on a main shaft 61 which is coaxial with the center axis of rotation of the plate cylinder 14 and which is rotatably supported by a frame of a stencil printing machine (not shown).
Is engaged.

The press cam 62 rotates in synchronization with the rotation of the plate cylinder 14. When the cam follower roller 60 follows the rotation of the press cam 62, the second link member 4
9 moves substantially vertically in FIG. 2 with the support shaft 59 via the cam lever 58 as a fulcrum. Also, the first link member 4
8 moves substantially vertically in FIG. 2 around the press shaft 41 via the press drive plate 43 as the second link member 49 moves. As described above, the link member formed by the first link member 48 and the second link member 49 reciprocates substantially vertically in accordance with the rotation of the press cam 62 synchronized with the rotation of the plate cylinder 14.

In the driving device for the press roller 18 having the above-described configuration, the state shown in FIG. 2 is a state in which the second link member 49 and the first link member 48 are moved downward by the rotation of the press cam 62. In this case, the press roller 18
Is the above-described retracted position separated from the outer peripheral surface of the plate cylinder 14. The hook member 4 of the press drive plate 43
In 5, the solenoid 46 is turned off, and the engagement with the press drive lever 42 is released. In the state shown in FIG. 2, the clamp portion 14a of the plate cylinder 14 is
In a non-printing state in which the printing paper P is not supplied between the plate cylinder 14 and the press roller 18 while avoiding interference between the press roller 18 and the clamp portion 14a at the rotation position facing the printing roller 8.

When the press cam 62 is rotated by the rotation of the plate cylinder 14 from the state shown in FIG. 2, the solenoid 46 is turned on in response to a signal indicating that the printing paper P is supplied, so that the hook member 45 is driven to press. The lever 42 is engaged. When the press cam 62 further rotates, the second link member 49 moves substantially upward as shown in FIG. When the second link member 49 moves upward, the first link member 48 moves substantially upward via the tension coil spring 56. One rotation end of the press drive plate 43 provided with the hook member 45 is rotated downward around the press shaft 41 by the movement of the first link member 48 as shown in FIG. The press drive lever 42 is moved downward by the hook member 45, and rotates the press shaft 41 counterclockwise in FIG. 3 to rotate the bracket 40 in the same direction. As a result, the press roller 18 is moved upward, and the plate cylinder 14 is moved.
Move to the pressure contact position pressed against the outer peripheral surface of.

At this time, the movement of the press roller 18 to the pressure contact position is performed by transmitting the upward movement of the second link member 49 to the first link member 48 while applying a spring force to the extension coil spring 56. Will be Then, in a state where the press roller 18 is pressed against the outer peripheral surface of the plate cylinder 14 with the printing paper P interposed therebetween, the rotation of the press cam 62 further raises the second link member 49, so that the second link member 49 is raised. Is displaced in the longitudinal direction with respect to the first link member 48, and the tension coil spring 56 is extended. As a result, the press roller 18 is pressed against the outer peripheral surface of the plate cylinder 14 with the printing paper P interposed therebetween by the spring force generated by the extension of the extension coil spring 56. This pressing force, that is, the printing pressure at the time of printing is determined by the spring force of the extension coil spring 56.

The printing pressure of the press roller 18 is adjusted by the adjusting screw 5 to which one end of the tension coil spring 56 is locked.
3 is adjusted by the printing pressure adjusting mechanism according to the third aspect. Hereinafter, the printing pressure adjusting mechanism will be described.

As shown in FIG. 2, the driving gear 6 is attached to the external gear 55 on the nut member 54 screwed to the adjusting screw 53.
3 are engaged. The drive gear 63 is fixedly attached to an output shaft 65 of a pulse motor 64 attached to the first link member 48. Therefore, the rotation of the output shaft 65 of the pulse motor 64 is controlled by the nut member 54 via the drive gear 63.
Is transmitted to

The adjusting screw 53 is provided with a detent member 6.
6 are provided. As shown in FIG.
Locking grooves 67 are formed on the sides of the upper end and the lower end, respectively. The rotation preventing member 66 is formed of a sheet metal bent in a substantially U-shape so as to have upper and lower locking pieces 68 that can be locked in the respective locking grooves 67. The rotation preventing member 66 is attached to the first link member 48 so as to be movable in the moving direction of the adjusting screw 53 by the rotation of the nut member 54.

The rotation preventing member 66 in this embodiment is mounted on a sensor fixing plate 69 fixedly mounted on the first link member 48. The sensor fixing plate 69 has a long slot 70 along the moving direction of the adjusting screw 53.
Are drilled. The detent member 66 is provided with the elongated hole 70.
It is attached to the sensor fixing plate 69 with a pin 71 that can be inserted into the sensor fixing plate 69 so that the adjusting screw 53 can be moved along the elongated hole 70 in the moving direction. Also, the detent member 66
The support plate 72 which is in contact with the side of the sensor fixing plate 69 is bent so that the pin 71 (rotation stop member 66) does not turn around the elongated hole 70. Note that a plurality of pins 71 may be provided instead of the support plate 72.

The position detection sensor 73 is fixed to the sensor fixing plate 69. The position detection sensor 73 is configured as an optical sensor including a light emitting unit and a light receiving unit.
The rotation preventing member 66 is formed with a bent detection piece 74 serving as a shielding plate for turning on / off the position detection sensor 73 when the rotation prevention member 66 moves with respect to the sensor fixing plate 69. That is,
The position detection sensor 73 is turned on / off by the movement of the adjustment screw 53.

In the printing pressure adjusting mechanism having the above configuration, the adjusting screw 53 is pulled upward by the spring force of the extension coil spring 56 as described above, and the nut member 54 is
It is in contact with 2. For this reason, when the rotation of the output shaft 65 of the pulse motor 64 is transmitted to the nut member 54 via the drive gear 63, the adjustment screw 53
In the axial direction (vertical direction). Then, the locking portion between the extension coil spring 56 and the adjusting screw 53 is displaced in the axial direction (up and down direction) with respect to the first link member 48, and the displacement changes the attachment length of the extension coil spring 56. As a result, the mounting load (spring force) of the tension coil spring 56 changes, and the pressing force for pressing the press roller 18 against the outer peripheral surface of the plate cylinder 14, that is, the printing pressure changes.
As described above, the external gear 55 of the nut member 54, the driving gear 63 for driving the external gear 55 to rotate, and the pulse motor 64 constitute a variable means for moving the adjusting screw 53 to vary the spring force of the extension coil spring 56. ing.

At this time, the rotation of the nut member 54 acts to rotate the adjusting screw 53 around the axis. However, the adjusting screw 53 includes the rotation preventing member 6.
Since the locking pieces 68 of FIG. 6 are locked, this co-rotation is suppressed.

The detection piece 74 on the rotation preventing member 66
Turns on / off the position detection sensor 73 at a fixed moving position of the adjusting screw 53 at all times. That is, the position detection sensor 7
No. 3 is always turned on / off at a fixed printing pressure position of the press roller 18. Thus, the printing pressure of the press roller 18 when the position detection sensor 73 is turned on or off is used as the reference printing pressure, and the spring force of the tension coil spring 56 and the moving amount of the adjustment screw 53 measured in advance are used to calculate the reference printing pressure. It is possible to obtain a desired printing pressure with the rotation amount of the pulse motor 64.

As a configuration for suppressing the co-rotation of the adjusting screw 53, a configuration shown in FIG. 5 is also conceivable as a modified example of the detent member 66 in the above-described embodiment. As shown in FIG. 5, the upper locking piece 68 of the rotation preventing member 66 is locked to the hook 56 a at one end where the tension coil spring 56 is locked to the adjusting screw 53, and moves together with the adjusting screw 53. It is constituted so that. In this case, the locking piece 68 below the detent member 66 may or may not be locked to the adjustment screw 53 as described above. As described above, even with the configuration shown in FIG. 5, it is possible to suppress the co-rotation of the adjusting screw 53. Further, the detection piece 74 makes it possible to detect the reference printing pressure of the press roller 18 by the position detection sensor 73 and obtain a desired printing pressure.

As a structure for suppressing the co-rotation of the adjusting screw 53, a structure shown in FIG. 6 is conceivable in addition to the rotation preventing member 66 in the above-described embodiment. FIG.
As shown in (a) and (b), a locking groove 80 is provided on the upper end surface of the adjusting screw 53. And, with respect to this locking groove 80,
A detent member 82 is appropriately locked by a pin 81 or the like.
The rotation preventing member 82 has a stopper piece 85 which is formed in a plate shape and is inserted into a slit 84 provided in a sensor fixing plate 83 fixed to the first link member 48. Further, one end of the tension coil spring 56 is locked to the rotation preventing member 82 so as to pass through several turns of the coil. Further, a part of the rotation preventing member 82 forms a shielding plate of the position detection sensor 73 fixed to the sensor fixing plate 83 as a detection piece. Thus, FIGS. 6A and 6B
Even with the configuration shown by, it is possible to prevent the co-rotation of the adjusting screw 53 with the rotation preventing member 82. Further, it is possible to detect the reference printing pressure of the press roller 18 by the position detection sensor 73 and obtain a desired printing pressure.

Therefore, in the printing pressure adjusting mechanism of the stencil printing machine configured as described above, when adjusting the printing pressure of the press roller 18, the adjusting screw 53 is rotated by rotating the nut member 54 to change the position of the adjusting spring 53. Are prevented by the detent members 66 and 82. Therefore, the tension coil spring 56 does not receive the rotational force in the torsional direction. Therefore, it is not necessary to consider the dynamic torque at which the adjusting screw 53 moves by the rotation of the nut member 54 and the torsional torque of the extension coil spring 56, and the degree of freedom in design can be increased.

Further, the co-rotation of the adjusting screw 53 is suppressed by the detent members 66 and 82 so that the tension coil spring 56 does not receive the rotational force in the torsional direction, so that the load on the tension coil spring is reduced. Therefore, it is possible to suppress the occurrence of spring breakage.

Also, since the tension coil spring 56 is prevented from receiving a rotational force in the torsional direction, the adjusting screw 53
Even if the dynamic torque varies due to the abrasion of the screw thread, the lubrication state, etc., there is no load on the tension coil spring 56, so that the occurrence of spring breakage due to the fluctuation of the dynamic torque can be suppressed. .

Since the tension coil spring 56 is prevented from receiving a rotational force in the torsional direction, the adjusting screw 53
When the operation is stopped, the position of the tension coil spring 56 can be determined, and a desired printing pressure can be obtained.

In the above-described embodiment, the detent members 66 and 82 are provided so as to be engaged with the adjusting screw 53 and move together with the adjusting screw 53 in the moving direction. Although not shown, the adjusting screw 53 is not shown.
For this purpose, a longitudinal locking hole or locking groove along the moving direction may be provided, and a detent member capable of locking the locking hole or locking groove may be fixedly mounted on the first link member 48 side. .

[0057]

As described above, the printing pressure adjusting mechanism for a stencil printing machine according to the first aspect of the present invention adjusts one end of a tension coil spring supporting the press roller when the press roller is moved. In the configuration in which the adjusting screw is moved by rotating the nut member screwed to the adjusting screw, the detent member provided in a portion which is locked to the adjusting screw and is not involved in the movement of the adjusting screw is provided. In addition, since the rotation of the nut member prevents rotation of the adjusting screw, the tension coil spring does not receive a rotational force in the torsion direction. Therefore, it is not necessary to consider the dynamic torque at which the adjusting screw moves by the rotation of the nut member and the torsional torque of the extension coil spring, and the degree of freedom in design can be increased.

In addition, since the rotation of the adjusting screw is suppressed so that the tension coil spring does not receive a rotational force in the torsional direction, the load on the tension coil spring is reduced, and the occurrence of spring breakage is suppressed. Can be.

Further, since the tension coil spring is prevented from receiving a rotational force in the torsional direction, even if the dynamic torque applied to the adjusting screw fluctuates due to abrasion of the screw thread, lubrication state, etc. Since there is no load on the coil spring, the occurrence of spring break due to the fluctuation of the dynamic torque can be suppressed.

Further, since the tension coil spring is prevented from receiving a rotational force in the torsion direction, the position of the tension coil spring can be determined when the adjusting screw stops.
A desired printing pressure can be obtained.

Further, as in the printing pressure adjusting mechanism of the stencil printing machine according to the second aspect, the detent member locks one end of the tension coil spring so that it is not involved in the movement of the adjusting screw. The above effect can be obtained even when the adjusting screw is provided so as to move in the moving direction of the adjusting screw.

Further, as in the printing pressure adjusting mechanism of the stencil printing machine according to the third aspect, the detent member locks with the adjusting screw and locks one end of the extension coil spring. Thus, the above-described effect can be obtained even if the adjustment screw is provided so as to move in a movement direction of the adjustment screw with respect to a portion not involved in the movement of the adjustment screw.

Further, as in the printing pressure adjusting mechanism of the stencil printing machine according to the fourth aspect, the rotation preventing member is configured to move in a moving direction of the adjusting screw with respect to a portion not involved in the moving of the adjusting screw. , By having a detection piece on the position detection sensor for detecting the movement position of the adjustment screw,
The printing pressure of the press roller when the position detection sensor is turned on or off is used as the reference printing pressure, and the adjustment screw is moved from the reference printing pressure by the relationship between the spring force of the tension coil spring and the amount of movement of the adjustment screw measured in advance. The desired printing pressure can be obtained by the amount.

[Brief description of the drawings]

FIG. 1 is a diagram showing a stencil printing machine with a stencil making function as an example of a stencil printing machine according to the present invention.

FIG. 2 is a side view showing a driving device of the press roller.

FIG. 3 is an operation diagram in FIG. 2;

FIG. 4 is an exploded perspective view showing a printing pressure adjusting mechanism.

FIG. 5 is a partial perspective view showing a modification of the printing pressure adjusting mechanism.

FIG. 6A is a perspective view showing another example of the printing pressure adjusting mechanism. (B) Partial sectional view showing another example of the printing pressure adjusting mechanism.

FIG. 7 is a side view showing a conventional press roller driving device and a printing pressure adjusting mechanism.

[Explanation of symbols]

14: plate cylinder, 18: press roller, 53: adjusting screw, 5
4 nut member, 66, 82 detent member, 73 position detecting sensor, 74 detection piece, 56 coil spring,
M: stencil paper, P: printing paper.

Claims (4)

[Claims] 1. A stencil sheet made of stencil is wrapped around an outer peripheral surface of a plate cylinder supplied with ink on an inner peripheral surface, and the plate cylinder is rotated, and a press roller is pressed against the outer peripheral surface of the stencil sheet to perform printing. A press-contact position for pressing the press roller against the outer peripheral surface of the plate cylinder at a predetermined timing synchronized with the rotation of the plate cylinder, in order to convey the sheet and perform stencil printing in a pressing manner on the printing paper; In a printing pressure adjusting mechanism for a stencil printing machine having a drive device for moving a press roller between a retracted position and an outer peripheral surface of the plate cylinder, a tension coil spring for supporting the press roller when the press roller is moved An adjusting screw for locking one end of the adjusting screw; and a nut member screwed to the adjusting screw. When the adjusting member is rotated in the axial direction when the nut member is rotated, the tension screw is moved. A variable means for changing the mounting length of the spring and varying the spring force thereof; and a means provided at a portion not involved in the movement of the adjustment screw so as to be locked to the adjustment screw, and the adjustment by rotation of the nut member. A printing pressure adjusting mechanism for a stencil printing press, comprising: a rotation preventing member that suppresses rotation of a screw. 2. The rotation preventing member according to claim 1, wherein the rotation preventing member is arranged to lock one end of the tension coil spring so as to move in a moving direction of the adjustment screw with respect to a portion not involved in the movement of the adjustment screw. The printing pressure adjusting mechanism for a stencil printing machine according to claim 1, wherein the printing pressure adjusting mechanism is provided. 3. The device according to claim 1, wherein the detent member locks the adjusting screw and locks one end of the tension coil spring, so that the rotation preventing member does not engage in the movement of the adjusting screw. The printing pressure adjusting mechanism for a stencil printing machine according to claim 1, wherein the printing pressure adjusting mechanism is provided so as to move in a moving direction of the adjusting screw. 4. A position detecting sensor for detecting the movement position of the adjustment screw, wherein the rotation preventing member is configured to move in a movement direction of the adjustment screw with respect to a portion not involved in the movement of the adjustment screw. The printing pressure adjusting mechanism for a stencil printing machine according to any one of claims 1 to 3, comprising the detecting piece according to any one of (1) to (3).