JPH0133352B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an ink leakage prevention device for a printing device, and more particularly, an ink reservoir having an open upper part, such as a rotary stencil printing device, The present invention relates to an ink leak prevention device for a printing device in which printing ink is supplied to the ink reservoir by an ink supply device.

As one of the single-cylinder stencil printing devices, it has a cylindrical plate cylinder with an ink-permeable structure that is driven to rotate around its central axis and has a stencil paper attached to its outer peripheral surface, and a cylindrical plate cylinder that has an ink-permeable structure on its inner peripheral surface. A printing ink supply roller that contacts the inner circumferential surface of the plate cylinder and rotates around its own central axis as the cylindrical plate cylinder rotates, and a predetermined minute interval between the printing ink supply roller and the outer circumferential surface of the printing ink supply roller. a doctor element disposed substantially parallel to the axis of the printing ink supply roller;
The outer circumferential surface of the printing ink supply roller and the outer circumferential surface of the doctor element define an ink reservoir portion with a wedge-shaped cross section that is open at the top, and the ink reservoir portion is supplied to the ink reservoir portion from an ink supply device. A printing apparatus according to the present invention has already been proposed in Japanese Patent Application No. 53-128043 (Japanese Unexamined Patent Publication No. 55889-1989) by the same applicant as the present applicant.

Regarding a printing device having an ink reservoir as described above, Japanese Patent Application No. 53-128044 (Special Publication No. 56-41436)
Or Japanese Patent Application No. 161418/1982 (Japanese Patent Application No. 62520/1983)
The amount of printing ink accumulated in the ink reservoir section is detected by a stylus type or capacitance type ink amount detection device proposed in The device replenishes the printing ink in the ink reservoir,
When the amount of ink accumulated in the ink reservoir reaches a predetermined value or more, the ink supply device stops replenishing the supply of printing ink to the ink reservoir, and the ink amount detection device and the signal from the ink amount detection device Therefore, as long as the ink supply device is operating normally, the amount of ink accumulated in the ink reservoir portion is controlled to a predetermined amount.

However, if the ink amount detection device malfunctions or malfunctions for some reason, the ink supply device may continue to supply printing ink to the ink reservoir even though there is a predetermined amount of printing ink in the ink reservoir. As a result, the amount of ink in the ink reservoir increases abnormally, printing ink overflows from the ink reservoir, and the printing ink leaks to the outside of the device, causing damage not only to the inside of the device but also to the installation. There is a risk that the area around the place will be contaminated.

Purpose of the Invention In view of the above-mentioned problems in conventional printing devices, the present invention provides an ink amount detection device that detects the amount of ink in the ink reservoir in order to control the amount of ink in the ink reservoir. Even if the amount of ink accumulated in the ink reservoir increases abnormally due to a malfunction for some reason, the ink supply device can remove the ink from the ink supply device before the amount of printing ink in the ink reservoir increases to the extent that it overflows to the outside. Ink leakage prevention that forcibly stops the supply of printing ink to the ink reservoir over the control by the ink amount detection device, and prevents the printing ink in the ink reservoir from overflowing to the outside of the ink reservoir. The purpose is to provide equipment.

According to the present invention, the above-mentioned object is to provide an ink leakage prevention device for a printing device that has an ink reservoir portion open at the top and in which printing ink is supplied to the ink reservoir portion by an ink supply device. A photoelectric ink detection means whose light is blocked by the printing ink when the amount of printing ink accumulated in the ink reservoir increases abnormally; This is achieved by an ink leakage prevention device having a control device that stops the ink supplying operation of the ink supplying device when an abnormal increase in the accumulated amount is detected.

Effects of the Invention According to the above-described configuration, when the amount of printing ink accumulated in the ink reservoir increases abnormally, the ink supplying action of the ink supplying device is stopped by a signal from the photoelectric ink detection means. The printing ink in the ink reservoir is prevented from overflowing from the ink reservoir, and the interior of the device and the vicinity of the installation location are prevented from being soiled by the printing ink.

The detection means for detecting an abnormal increase in the amount of ink accumulated in the ink reservoir is a photoelectric type, so it is more reliable in detecting the presence or absence of printing ink than a stylus type or capacitance type. Therefore, in addition to the ink amount detection device for controlling the amount of ink accumulated in the ink reservoir, there is almost no possibility that the photoelectric ink detection means will malfunction, and the printing ink detected by the photoelectric ink detection means Based on the presence or absence of this, it is possible to reliably prevent the amount of ink in the ink reservoir from increasing to the extent that printing ink overflows.

In addition, if the photoelectric ink detection means has its light emitting surface or light emitting surface soiled by printing ink, the light will remain blocked unless the dirt is wiped off. Although this device has excellent reliability, it cannot be used as an ink amount detection device for controlling the amount of ink pool, as it must repeatedly detect increases and decreases in the amount of ink pool. However, due to the above-mentioned drawbacks, this photoelectric ink detection means cannot be used for detecting an abnormal operating state to detect an abnormal increase in the amount of ink accumulated in the ink reservoir, as in the ink leakage prevention device of the present invention. It is suitable as an ink amount detection device, and unless the light projecting surface or light emitting surface is wiped off during maintenance inspection, it will maintain a state in which it detects an abnormal increase in the amount of ink in the ink reservoir, and will detect an abnormal state. This has the effect of reliably preventing the ink supply device below from restarting.

The invention will now be described in detail by way of example embodiments with reference to the accompanying drawings.

FIGS. 1 and 2 show the main parts of one embodiment of a printing apparatus equipped with an ink leakage prevention device according to the present invention.

In these figures, reference numeral 1 indicates a cylindrical plate cylinder, which has a porous structure that allows printing ink to pass through, has a stencil paper 2 attached to its outer circumferential surface, and is self-adhesive. It is designed to be rotationally driven in the counterclockwise direction in the figure by a drive device (not shown) around the central axis of the figure.

An ink supply roller 3 having a diameter sufficiently smaller than the cylindrical plate cylinder 1 is disposed within the cylindrical plate cylinder 1. The ink supply roller 3 is provided parallel to one generatrix of the cylindrical plate cylinder 1, is rotatably supported by a support frame 5 around its own central axis by support shafts 4 provided at both ends, and has an outer periphery. A part of the surface contacts the inner circumferential surface of the cylindrical plate cylinder 1, and is rotated counterclockwise in the figure in synchronization with the rotation of the cylindrical plate cylinder 1.

The support frame 5 fixedly supports the doctor rod 6 diagonally above the ink supply roller 3. The doctor rod 6 is disposed substantially parallel to the axis of the ink supply roller 3 at a predetermined minute interval 7 from the outer peripheral surface of the ink supply roller 3, and is arranged between the ink supply roller 3 and the ink supply roller 3 on one side of the minute gap 7. Together, they define an ink reservoir 8 with a wedge-shaped cross section that is open at the top.

Although the ink reservoir section 8 is open at the top, both ends are limited by the support frame 5, and printing ink having an appropriate viscosity is supplied to the ink reservoir section from the ink supply port 10 of the ink supply pipe 9. supply is becoming available. Ink supply pipe 9
is connected in communication with a discharge port of an electric ink supply pump (not shown), and the ink supply pump selects printing ink sucked from an ink supply source such as an ink tube in accordance with the operation of the ink supply pump. It is becoming more and more widely available.

A printed circuit board 11 for controlling the amount of ink accumulation is removably attached to the upper part of the support frame 5, and a needle electrode 12 constituting a capacitance type ink amount detection device 32 and a needle electrode 12 constituting a capacitive ink amount detection device 32 are mounted on the printed circuit board. Various electrical elements 13 such as capacitors are attached.
In the capacitive ink amount detection device, the dielectric constant between the needle-shaped electrode 12, which is provided hanging down from the print board 11 to the ink reservoir portion 8, and the ink supply roller 3, which is opposed to the needle-shaped electrode 12, is the same as that between the two. The amount of printing ink accumulated in the ink reservoir 8 is detected in order to control the amount of accumulated printing ink based on the fact that the amount of printing ink accumulated in the ink reservoir 8 varies depending on the amount of accumulated printing ink in the ink reservoir 8. . If a more detailed explanation of this capacitance type ink amount detection device is required, please refer to Japanese Patent Laid-Open No. 1983-62520.

A light emitting/receiving unit (photoelectric ink detection means) such as a photointerrupter is mounted on the bottom surface of the printed circuit board 11.
14 is removably provided. The light emitting/receiving unit 14 includes a staple-shaped casing 15 having a pair of legs, and is attached to one leg of the casing 15 and emits light toward the other leg through a gap 16 between the pair of legs. It includes a light emitting element 17 such as a light emitting diode, and a light receiving element 18 such as a phototransistor which is attached to the other leg of the casing 15 and is irradiated with the light emitted by the light emitting element 17. When no blocking material is present, the light beam emitted by the light emitting element 17 reaches the light receiving element 18 and turns on, whereas when a light blocking material such as printing ink is present in the gap 16, no light is emitted. The light emitted by the optical element 17 is blocked by the light blocking substance, and the light is transmitted to the light receiving element 18.
The state is turned off by not reaching .

The light emitting/receiving unit 14 detects the amount of ink in the ink reservoir 8 that exceeds a predetermined amount to stop the operation of the ink supply pump based on the amount of ink in the ink reservoir 8 detected by the capacitive ink amount detection device 32. The mounting height position is adjusted so that when the amount of ink pooling in the ink reservoir section 8 increases, that is, when the amount of ink pooling in the ink reservoir section 8 increases abnormally, the printing ink enters into the gap 16. In this case, as clearly shown in FIG. 2, one each is attached near both ends of the ink reservoir 8 at the same height position.

The light emitting/receiving unit 14 includes bar-shaped electrical connection terminals 19 and 20 of the light emitting element 17 and the light receiving element 18, respectively.
Each of the electrical connection terminals is a plate-shaped electrical connection terminal made of a spring that protrudes from the casing 15 and is attached to the printed circuit board 11 through holes 21 and 22 formed in the printed circuit board 11. 23 and 24 to electrically connect the printed circuit board 11 and the light emitting/receiving unit 14, and simultaneously fixing the light emitting/receiving unit 14 to the printed circuit board 11.

FIG. 4 shows an electrical circuit diagram of an ink leak prevention device and an ink supply amount control device related thereto. The control device connects one transistor 25 whose base terminal is connected to the collector terminal of the light receiving element 18 of one of the two light emitting and receiving units 14, and one transistor 25 whose base terminal is connected to the collector terminal of the light receiving element 18 of one of the two light emitting and receiving units 14. Another transistor 26 is connected to the collector terminal of the light receiving element 18 of the other light emitting/receiving unit, and the collector terminals of these two transistors 25 and 26 are connected to each other to form an output terminal 27 of one OR gate. It consists of The output terminal 27 is adapted to output an on-off signal to the drive circuit 29 of the display device 28 and one input terminal of the AND gate 30.

The drive circuit 29 is adapted to cause the display device 28 to display when an off signal is applied from the output terminal 27.

Another input terminal of the AND gate 30 is connected to an ink supply amount control circuit 31, and the ink supply amount control circuit 31 detects that the capacitance type ink amount detection device 32 detects an ink amount exceeding a predetermined amount. An ON signal is output to the AND gate 30 only when there is no ink, that is, when the amount of ink in the ink reservoir 8 is less than a predetermined value. and gate 3
The output terminal 0 is connected to the drive circuit 34 of the ink supply pump driving electric motor 33, and the electric motor 33 is driven only when the AND gate 30 outputs an ON signal.

With the above-described configuration, the electric motor 33 ensures that when the output terminal 27 of the OR gate outputs an ON signal, that is, the printing ink does not enter into any of the gaps 16 of the casings 15 of the two light emitting/receiving units 14. The light beams emitted by the light emitting elements 17 of the two light emitting/receiving units 14 each reach the light receiving element 18, the amount of ink in the ink reservoir portion 8 has not increased abnormally, and the amount of ink for controlling the amount of ink pool can be detected. It operates only when the device 32 detects that the amount of ink in the ink reservoir 8 is below a predetermined value, and drives the ink supply pump.

In the unlikely event that the ink amount detection device 32 or the ink supply amount control circuit 31 for controlling the amount of ink pool fails or malfunctions for some reason, the amount of printing ink stored in the ink reservoir portion 8 exceeds a predetermined value. Despite this, the electric motor 33 is operated and the ink supply pump is driven, and printing ink is supplied from the ink supply port 10 of the ink supply pipe 9 to the ink reservoir 8, thereby causing the ink reservoir in the ink reservoir 8 to When the amount of printing ink increases abnormally, a portion of the printing ink in the ink reservoir 8 enters into the gap 16 of at least one of the casings 15 of the two light emitting/receiving units 14. Gap 1
When printing ink enters into the light receiving element 18 , the printing ink stains the light emitting surface of the light emitting element 17 or the light receiving surface of the light receiving element 18 , thereby blocking the light emitted by the light emitting element 17 . , the light receiving element 18 is turned off, and the output terminal of the OR gate 27 begins to output an off signal. By this and gate 30
starts outputting an off signal to the drive circuit 34 even if it is given an on signal from the ink amount control circuit 31, and accordingly, the operation of the electric motor 33 is stopped, and the drive of the ink supply pump by the electric motor is stopped. This stops printing ink from being further supplied from the ink supply port 10 of the ink supply tube 9 to the ink reservoir 8. At the same time, the display device 28 lights up to indicate that the device has stopped due to abnormal operation and that maintenance by a service person is required.

When printing ink enters the gap 16 of the light emitting/receiving unit 14, the printing ink stains the light emitting surface of the light emitting element 17 or the light receiving surface of the light receiving element 18.
Even if the printing ink in the ink supply device is removed, the ink supply device remains in the off state and will not turn on unless the light emitting surface of the light emitting element 17 and the light receiving surface of the light receiving element 18 are manually wiped off. No restart will occur.

The light emitting/receiving unit 14 is designed to be easily attached to and detached from the printed circuit board 11 through its electrical connection terminals 19 and 20 so that the above-mentioned wiping operation can be easily performed.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto, and various embodiments are possible within the scope of the present invention. It will be clear to those skilled in the art.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing the main parts of one embodiment of a printing device incorporating an ink leak prevention device according to the present invention, and FIG. 2 is a schematic perspective view of the printing device shown in FIG. 1. FIG. 3 is a perspective view showing the mounting structure of the light emitting/receiving unit used in the ink leak prevention device according to the present invention, and FIG. FIG. 2 is an electrical circuit diagram showing the circuit. DESCRIPTION OF SYMBOLS 1... Cylindrical plate cylinder, 2... Stencil paper, 3... Ink supply roller, 4... Support shaft, 5... Support frame, 6... Doctor rod, 7... Minute gap, 8...
...Ink reservoir, 9...Ink supply pipe, 10
...Ink supply port, 11...Print board,
12...Acicular electrode, 13...Electric element, 14...
Light emitting/receiving unit, 15...Casing, 16...
Gap, 17... Light projecting element, 18... Light receiving element, 1
9, 20...Electrical connection terminal, 21, 22...
Hole, 23, 24...Electrical connection terminal, 25, 26
...Transistor, 27...Output terminal of OR gate, 28...Display device, 29...Drive circuit,
30...AND gate, 31...Ink supply amount control circuit, 32...Ink amount detection device for controlling ink pool amount, 33...Electric motor, 34...Drive circuit.

Claims (1)

[Claims] 1. In an ink leakage prevention device for a printing device having an ink reservoir portion open at the top and in which printing ink is supplied to the ink reservoir portion by an ink supply device, the ink leakage prevention device in the ink reservoir portion a photoelectric ink detection means that blocks light by staining a light emitting surface or a light receiving surface with the printing ink when the amount of printing ink abnormally increases; An ink leakage prevention device comprising: a control means for stopping the ink supplying action of the ink supplying device when an abnormality in the amount of ink is detected.