JP3048756B2 - Ink detector for stencil printing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink amount detecting device for a stencil printing machine.

[0002]

2. Description of the Related Art A stencil printing apparatus is a roller type which extends in the axial direction of a rotationally driven plate cylinder and slides on the inner peripheral surface of the plate cylinder.
Alternatively, it has a blade type squeegee member, and the squeegee member is configured to supply the printing ink in the ink reservoir formed by extending in the axial direction of the plate cylinder to the plate cylinder.

In the stencil printing apparatus as described above, an ink amount detecting device for detecting the amount of ink in the ink reservoir is provided for controlling ink supply to the ink reservoir.

[0004] In this ink amount detecting device, the ink reservoir is determined based on a change in the electrostatic capacity between the detection electrode member and the ground electrode member that are opposed to each other with the ink reservoir portion interposed therebetween. An ink amount detecting device for detecting a change in the amount of ink in the printing section has already been proposed, which is disclosed in Japanese Utility Model Publication No. 3-28342 and Japanese Patent Publication No. 1-33352.
And JP-A-62-146632.

[0005]

In the above-described capacitance type ink amount detecting device, when printing ink adheres to a circuit board or the like, erroneous detection occurs and the device is not electrically stable. If not the atmosphere, arising erroneous detection. others
Ink supply system using a blade-type squeegee member
When the ink reservoir is in a narrow area between the squeegee member and the metal plate cylinder as in the stencil printing apparatus described above, an electrically stable atmosphere cannot be obtained and erroneous detection is likely to occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the conventional ink amount detecting apparatus, and is unlikely to cause erroneous detection. Further, the ink reservoir portion has a squeegee member and a metal plate cylinder. It is an object of the present invention to provide an ink amount detecting device for a stencil printing apparatus that stably and reliably detects the ink amount in an ink reservoir portion without being affected by disturbance even in a narrow area between them.

[0007]

According to the present invention, there is provided a squeegee member which extends in the axial direction of a rotationally driven plate cylinder and slides on the inner peripheral surface of the plate cylinder. In the ink amount detecting device for a stencil printing machine configured to supply printing ink in an ink reservoir formed by extending the squeegee member in the axial direction of the plate cylinder to the plate cylinder, When the ink amount of the ink reservoir is equal to or less than a predetermined value, an ink suction port is provided at a position separated from the printing ink of the ink reservoir, and the printing ink of the ink reservoir is suctioned from the ink suction port. A pump for discharging ink from the ink discharge port to the ink reservoir, and ink suction detecting means for detecting whether or not the pump for ink circulation suctions printing ink. Ink amount of the ink reservoir from the detection result of the suction detecting means is achieved by the ink amount detecting device of the stencil printing apparatus and detects whether a predetermined value or less.

[0008]

According to the above construction, when the amount of ink in the ink reservoir is less than a predetermined value, the ink circulation pump cannot suck the printing ink and sucks air.
This is the amount of ink is detected ink reservoir by the ink suction detecting means is detected to be below a predetermined value.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an embodiment of the present invention.

FIGS. 1 and 2 show an embodiment of an ink amount detecting device of a stencil printing apparatus according to the present invention. In these figures, reference numeral 1 denotes a cylindrical plate cylinder.
Is made of an ink-permeable material such as a porous metal plate or a mesh structure. The printing drum 1 is wound around a stencil sheet (not shown) around the outer peripheral surface thereof, and is driven to rotate counterclockwise in the drawing around its own central axis by printing drum rotation driving means (not shown). The printing paper (not shown) is pressed against the stencil sheet on the outer peripheral surface of the plate cylinder by the press roller 3 in a rotating state, thereby performing stencil printing on the printing paper.

A staple-shaped squeegee support frame 5 is fixedly arranged in the plate cylinder 1.

The squeegee support frame 5 rotatably supports a squeegee roller 11 by a center shaft 9 between a pair of side plate portions 7 located on both axial sides of the plate cylinder 1. The squeegee roller 11 extends in the axial direction of the plate cylinder 1 and slides on the inner peripheral surface of the plate cylinder 1. The squeegee roller 11 is driven by a sprocket 13 attached to the central shaft 9 and a timing belt 15 engaged with the sprocket 13. The motor is driven to rotate counterclockwise in synchronization with the rotation of.

The squeegee support frame 5 supports the doctor rod 17 between the side plates 7 in parallel with the squeegee roller 11 and with a predetermined ink outflow gap 19 with respect to the outer peripheral surface of the squeegee roller 11.

Printing ink is supplied to the outer peripheral surface of the squeegee roller 11 from an ink supply pipe 21.
An ink reservoir P is formed on the squeegee roller 11 by the printing ink 7 from the ink supply pipe 21 with the dam 7 as a weir.

An ink circulation pump 23 is mounted on the squeegee support frame 5. Ink circulation pump 23
Is constituted by, for example, a small gear pump and is driven by a motor 25.

The ink circulation pump 23 has a suction hose 27
And the discharge hose 29 are connected. Suction hose 27
Is branched into two portions, each end of which extends on both sides in the axial direction of the plate cylinder 1 and faces the upper portion of the ink reservoir P on both sides in the axial direction, and forms ink suction ports 31 respectively. . When the amount of ink in the ink reservoir P is equal to or less than a predetermined value, the position of the ink suction port 31 in the vertical direction is set to a position separated from the printing ink in the ink reservoir P as shown in FIG. .

The discharge hose 29 extends to the center of the plate cylinder 1 in the axial direction, and faces the upper part of the ink reservoir P at the center in the axial direction to form an ink discharge port 33.

The power supply circuit of the motor 25 has a current detector 35.
Is attached, and the current detector 35 detects the value of the current supplied to the motor 25. The energizing current value of the motor 25 detected by the current detector 35 is input to the current value determination circuit 37.

The current value judging circuit 37 compares the supplied current value from the current detector 35 with a predetermined comparison reference value. If the supplied current value is equal to or larger than the comparison reference value, the ink in the ink reservoir P An ink amount detection signal indicating that the amount is equal to or more than a predetermined value is generated, and if the supplied current value is not equal to or greater than the comparison reference value, the ink amount indicating that the ink amount in the ink reservoir P is equal to or less than the predetermined value. A detection signal is generated.

According to the above configuration, the motor 25 drives the ink circulation pump 23 to rotate, and the ink circulation pump 23 drives the ink suction port 31 to generate a suction force. At this time, if the amount of ink in the ink reservoir P is equal to or greater than a predetermined value, the ink suction ports 31 come into contact with the printing ink in the ink reservoir P at both sides in the axial direction of the plate cylinder 1, Aspirate the printing ink present on both sides. The printing ink sucked into the ink suction port 31 flows through the suction hose 27 and reaches the ink circulation pump 23, thereby flowing through the discharge hose 29, and is discharged from the ink discharge port 33, and is discharged from the ink discharge port 33 in the axial center of the plate cylinder 1. Is returned to the ink reservoir P.

Due to the flow of the printing ink by the ink circulation pump 23, the printing ink in the ink reservoir P is transferred to the plate cylinder 1.
Circulating in the axial direction of the plate cylinder 1, so that the printing ink existing in the axially opposite end regions of the plate cylinder 1 in the ink reservoir P is prevented from being consumed for a long time.

As described above, when the ink circulation pump 23 is sucking the printing ink from the ink suction port 31, the pump driving load of the motor 25 is larger than when the ink is sucking the air. The energizing current value of the motor 25 detected by the detector 35 is equal to or greater than the comparison reference value in the current value judging circuit 37.

Therefore, at this time, the current value judging circuit 37
By comparing the current carrying value from the current detector 35 with the comparison reference value, it is determined that the current carrying value is greater than or equal to the comparison reference value,
An ink amount detection signal indicating that the amount of ink in the ink reservoir P is equal to or greater than a predetermined value is generated.

When the printing ink in the ink fountain P is consumed and the amount of the printing ink falls below a predetermined value, the ink suction port 31
Is separated from the printing ink in the ink reservoir P and sucks air. At this time, the pump driving load of the motor 25 is smaller than when the ink circulation pump 23 is sucking the printing ink from the ink suction port 31. Therefore, the current flowing through the motor 25 detected by the current detector 35 is reduced. The value becomes equal to or less than the comparison reference value in the current value judgment circuit 37, and the current value judgment circuit 37 compares the energization current value from the current detector 35 with the comparison reference value and determines that the energization current value is equal to or less than the comparison reference value. By making a determination, an ink amount detection signal indicating that the amount of ink in the ink reservoir P is equal to or less than a predetermined value is generated. At this time, the control of replenishing the printing ink in the ink tank (not shown) from the ink supply pipe 21 to the ink reservoir P may be performed in a known manner.

In the above-described embodiment, whether or not the ink circulation pump 23 is sucking the printing ink is determined as follows.
The detection is performed by detecting a change in the value of the energizing current of the motor 25. This detection is performed by an ink flow sensor 3 connected in the middle of the suction hose 27 as shown in FIG.
8 may be performed by detecting whether or not the printing ink is flowing in the suction hose 27. The ink flow sensor 38 is, for example, a flapper type. When the printing ink is flowing, the flapper tilts due to the dynamic pressure thereof, and the tilting of the flapper may be detected by a limit switch or the like.

As shown in FIG. 2, the suction hose 27
Is branched into two, the ink flow sensor 3
8 may be provided at any one or both of the forked portions of the suction hose 27, or at the gathering portion of the suction hose 27, and when provided at both of the forked portions of the suction hose 27, provided at each of the forked portions. The ink amount detection signal may be formed by any logical processing of the output signal of the ink flow sensor 38 by AND or OR, and these are optimally set in accordance with the ink shape in the ink reservoir P or the like. Just do it.

In this case, two ink suction ports 3 are provided.
The arrangement positions of the first and second ink suction ports 31 do not necessarily have to be the same, and a difference may be provided in the arrangement position of the two ink suction ports 31 in the up and down direction. The detection can be performed in two steps, and this can be used, for example, for ink supply forcible stop control when the amount of ink in the ink reservoir P has increased above.

In the above embodiment, the suction hose 27
Are bifurcated to suck the printing ink from both sides in the axial direction of the plate cylinder 1 and to return the printing ink to the central portion in the axial direction of the plate cylinder 1, but otherwise shown in FIG. As shown, the suction hose 27 extends to one side of the plate cylinder 1 in the axial direction, the ink suction port 31 is disposed only on one side in the axial direction, and the discharge hose 29 is connected to the plate cylinder 1 in the axial direction. Even if the ink discharge port 33 is arranged on the other side in the axial direction extending to the other side, as shown in FIG. 5, the suction hose 27 is connected to one side of the plate cylinder 1 in the axial direction. To the ink suction port 31 only on one side in this axial direction.
May be disposed, and the ink discharge port 33 of the discharge hose 29 may be disposed in a substantially central region of the plate cylinder 1 in the axial direction. Further, although not shown in the drawing, the ink suction port 31 is connected to the axis of the plate cylinder 1. Even if the ink discharge port 33 is disposed in the axial direction end area of the plate cylinder 1, the ink suction port 3
1 and the ink discharge port 33 may be arranged at the same position as viewed in the axial direction of the plate cylinder 1.

In any of these cases, when the vertical position of the ink suction port 33 is equal to or less than the predetermined value, the ink suction port 33 is separated from the printing ink in the ink pool P when the amount of ink in the ink pool P is below a predetermined value. By setting to the position where
In the same manner as in the above-described embodiment, the ink amount in the ink reservoir P is detected.

FIG. 6 shows another embodiment of the ink amount detecting apparatus of the stencil printing apparatus according to the present invention. In FIG. 6, portions corresponding to FIGS. 1 and 2 are denoted by the same reference numerals as those given to FIGS. In this embodiment, left and right squeegee support side plates 43 connected to each other by a connection shaft 41 extending along the axial direction of the plate cylinder 1 are provided in the plate cylinder 1. The squeegee blade 51 is supported in parallel with the axial direction of the plate cylinder 1 by a squeegee support board 45 stretched between them and a squeegee support mounting plate 49 fixedly mounted on the squeegee support board 49 with screws 47.

The squeegee blade 51 is made of a rubber-like elastic material such as urethane rubber.
5 and is cantilevered by the squeegee support mounting plate 49, extends in the axial direction of the plate cylinder 1, and has a free edge, which is a leading edge, pressed against the inner peripheral surface of the plate cylinder 1 at a predetermined squeegee angle.

In this case, the printing ink is supplied from the ink supply pipe 21 to the inner peripheral surface of the plate cylinder 1, so that the squeegee blade 41 and the plate are rotated with the clockwise rotation of the plate cylinder 1 in the drawing. An ink reservoir P is formed on the side delayed from the contact position with the cylinder 1 in the rotation direction of the plate cylinder 1, that is, in the triangular area on the right side of the contact position as viewed in FIG.

One end of a swing lever 53 is pivotally connected to the connection shaft 41, and the swing lever 53 is connected to the support shaft 5 having an intermediate portion attached to a fixed frame (not shown).
5, and a cam follower roller 57 is rotatably supported at the other end.

The cam follower roller 57 includes a swing lever 5
3 is urged in the counterclockwise direction in the figure by a spring 59 attached to the connecting shaft 41, thereby engaging with the cam 63 of the cam shaft 61 rotatably supported by the fixed frame. . The cam shaft 61 is driven to rotate by gears 65 and 67 in a one-to-one transmission relationship in synchronization with the rotation of the plate cylinder 1.

The other end of the squeegee support side plate 43 has a spring 6
9, the other end is fixed to the fixed frame so that the mounting angle can be adjusted.
It is in contact with 1.

Due to this contact relationship and the above-described cam mechanism, the squeegee support side plate 43 and the squeegee blade 51 accompanying the squeegee support plate correspond to the non-ink passage area of the stencil sheet clamp portion formed in a part of the plate cylinder 1. During the rotation phase section, the plate cylinder 1 is forcibly separated from the inner peripheral surface of the plate cylinder 1.

Also in this embodiment, an ink circulation pump 23 is provided, and an ink suction port 3 is provided by a suction hose 27.
1 is disposed above the ink reservoir P, the ink discharge port 33 is disposed by the discharge hose 29 at a position delayed from the ink reservoir P in the rotation direction of the plate cylinder 1, and the ink suction port 31 is controlled by the ink circulation pump 23. The printing ink in the ink reservoir P is further sucked and the printing ink is sucked into the ink discharge port 33.
The ink is further discharged toward the ink reservoir P.

In this embodiment as well, when the ink suction port 33 is disposed at a position equal to or less than a predetermined value, the ink suction port 33 is separated from the printing ink in the ink pool P, as in the above-described embodiment. By setting the position, the amount of ink in the ink reservoir P is detected in the same manner as in the above-described embodiment.

In the illustrated embodiment, the suction hose 27
Is fixedly supported by the hose stopper 73 by the screw 47 from the squeegee support substrate 35, whereby the arrangement position of the ink suction port 33 is stably maintained.

The ink suction port 3 of the ink circulation pump 23
1 and the ink discharge port 33, as in the above-described embodiment,
Since the ink circulation pump 23 is freely disposed at a position separated from the ink circulation pump 23 by the suction hose 27 and the discharge hose 29, the ink circulation pump 23 It is arranged at a free position distant from P, and this arrangement position is not subject to space restrictions than the narrow ink reservoir P.

FIG. 7 shows an embodiment of an ink supply system of a stencil printing apparatus including an ink amount detecting device according to the present invention.
In this embodiment, a flow path switching valve 81 is provided in the middle of the suction hose 27, and the flow path switching valve 81 connects the ink circulation pump 23 to one of the ink suction port 31 and the ink supply hose 83. Is configured to be selectively connected to.

An ink bottle 85 is connected to the ink supply hose 83 as an ink tank.

The flow path switching valve 81 is provided with an ink supply control device 87.
The ink supply control device 87 receives the ink amount detection signal from the current value determination circuit 37. If the ink amount detection signal from the current value determination circuit 37 is a signal indicating that the ink amount in the ink reservoir P is equal to or greater than a predetermined value, the ink supply control device 87 supplies the ink circulation pump 23 with the ink. When the ink amount detection signal from the current value determination circuit 37 is a signal indicating that the amount of ink in the ink reservoir P is equal to or less than a predetermined value, the hose is disconnected from the hose 83 and connected to the ink suction port 31. The ink circulation pump 23 to the ink suction port 3
A drive signal that is separated from the first and connected to the ink supply hose 83 is output to the flow path switching valve 81.

Thus, when the amount of ink in the ink reservoir P is equal to or greater than a predetermined value, the ink circulation pump 23 is disconnected from the ink supply hose 83 and the ink suction port 31 is opened.
And the printing ink in the ink pool P is sucked from the ink suction port 31 and returned to the ink pool P through the ink discharge port 33.

When the amount of ink in the ink reservoir P falls below a predetermined value and the ink circulation pump 23 stops sucking the printing ink in the ink reservoir P from the ink suction port 31, the drive output by the ink supply controller 87 is performed. The signal switches the flow path switching valve 81 to connect the ink circulation pump 23 to the ink supply hose 83 instead of the ink suction port 31. As a result, the ink circulation pump 23 sucks the printing ink from the ink bottle 85, and the printing ink in the ink bottle 85 is supplied from the ink discharge port 33 to the ink reservoir P.

When the ink circulation pump 23 sucks the printing ink from the ink bottle 85, the current value determination circuit 3
7, the ink amount detection signal is inverted, but this is canceled to prevent hunting, and the ink circulation pump 23 sucks the printing ink from the ink bottle 85 for a predetermined time by time control or the like. May be maintained.

In this case, an ink supply pump for supplying printing ink from the ink bottle 85 to the ink reservoir P can be omitted, and the ink amount detection signal from the current value judgment circuit 37 is used to detect the ink amount of the ink bottle 85. It is also possible to detect that the printing ink has run out.

Also in this embodiment, whether the ink circulation pump 23 is sucking the printing ink or not is detected by the ink flow sensor 3 connected in the middle of the suction hose 27.
8 may of course be performed.

[0049]

As can be understood from the above description, according to the ink amount detecting device of the stencil printing apparatus according to the present invention, the ink suction port of the ink circulation pump is provided with the ink amount of the ink reservoir portion being equal to or less than a predetermined value. Sometimes the ink reservoir is provided at a position separated from the printing ink in the ink reservoir, and an ink suction detecting means for detecting whether the ink circulation pump is sucking the printing ink is provided. When the amount is less than the predetermined value, the ink circulation pump becomes unable to suck the printing ink and sucks air. This is detected by the ink suction detecting means, and the amount of ink in the ink reservoir is less than the predetermined value. Erroneous detection is unlikely to occur, and even if the ink reservoir is in a narrow area between the squeegee member and the metal plate cylinder, it will be affected by disturbance. Ku is the ink amount detection of the ink reservoir so is ensured stably.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an ink amount detecting device of a stencil printing apparatus according to the present invention.

FIG. 2 is a schematic perspective view showing an embodiment of an ink amount detecting device of the stencil printing apparatus according to the present invention.

FIG. 3 is a schematic configuration diagram showing another embodiment of the ink amount detecting device of the stencil printing apparatus according to the present invention.

FIG. 4 is a schematic configuration diagram showing another embodiment of the ink amount detecting device of the stencil printing apparatus according to the present invention.

FIG. 5 is a schematic configuration diagram showing another embodiment of the ink amount detecting device of the stencil printing apparatus according to the present invention.

FIG. 6 is a schematic configuration diagram showing another embodiment of the ink amount detecting device of the stencil printing apparatus according to the present invention.

FIG. 7 is a schematic configuration diagram showing an embodiment of an ink supply system of a stencil printing apparatus including an ink amount detection device according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 plate cylinder 3 press roller 5 squeegee support frame 11 squeegee roller 17 doctor rod 23 ink circulation pump 25 motor 27 suction hose 29 discharge hose 31 ink suction port 33 ink discharge port 35 current detector 37 current value judgment circuit 38 ink flow sensor 43 squeegee Support side plate 53 Swing lever 57 Cam follower roller 63 Cam 81 Flow path switching valve 85 Ink bottle P Ink reservoir

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41L 13/18 B41L 13/04 B41F 31/02 B41F 31/20

Claims (1)

(57) [Claims] 1. A squeegee member extending in the axial direction of a rotationally driven plate cylinder and slidably contacting the inner peripheral surface of the plate cylinder, wherein the squeegee member extends in the axial direction of the plate cylinder. In the ink amount detecting device of the stencil printing machine configured to supply the printing ink of the ink reservoir to the printing drum by soaking, the ink reservoir of the ink reservoir is not more than a predetermined value. An ink circulation pump having an ink suction port arranged at a position separated from the printing ink, sucking the printing ink in the ink reservoir from the ink suction port, and discharging the printing ink from the ink discharge port to the ink reservoir. And, having an ink suction detection means to detect whether the ink circulation pump is suctioning the printing ink,
An ink amount detecting device for a stencil printing machine, wherein whether or not the ink amount in the ink reservoir is less than or equal to a predetermined value is detected from the detection result of the ink suction detecting means.