GB2139146A - Single cylinder type rotary mimeograph printing machine - Google Patents

Abstract

A single cylinder type rotary mimeograph printing machine wherein a signal of a microswitch 12 which comes to be active when the ink collecting 6 portion on the plate cylinder is at prescribed lower positions and a signal which comes to be active at non-printing state are put in the NOR circuit 14, and the timer 15 is made to operate by the outputs of the NOR circuit to rotate the motor at the time-up signal to make the ink collecting portion travel to the prescribed lower positions. The timer may also actuate an alarm just before the drum is rotated, and an overriding safety device may also be provided, to prevent the rotation, eg when other machine adjustments, such as replacement of the stencil, are being undertaken. <IMAGE>

Description

SPECIFICATION Single cylinder type rotary mimeograph printing machine The present invention relates to a single cylinder type rotary mimeograph printing machine which performs printing on the printing paper fed between a plate cylinder and an impression cylinder which closely contact each other and rotate together, first by sticking the processed stencil paper to the plate cylinder wherein ink is put inside, having the ink which comes oozing out from the inside of the plate cylinder appear on the surface through the processed part of the stencil paper, and transferring the ink which has appeared at the processed part to the printing paper.

As the method of having the ink which is put inside the plate cylinder appear on the surface in a printing machine of this kind, there are two methods, namely, one according to which pressure is applied inside the plate cylinder and the other wherein the centrifugal force by the rotation or the capillary phenomenon or the like is made use of. Of these two methods, the former requires a pressure device separately and so it costs much. Therefore, the latter is adopted in most cases.A printing machine of the latter, however, has such a defect that the ink put inside the plate cylinder comes out overflowing to the surface of the plate cylinder through the ink oozing-out portion, if the plate cylinder is let alone several minutes with the ink oozing-out portion being at its lower side, and the printing machine will be stained due to the dripping of the ink outside the plate cylinder through the processed part even when a stencil paper is mounted on the plate cylinder. Moreover, the ink drips also on the impression cylinder which is located beneath the plate cylinder, and if the printing has been performed at such a state, remarkable irregularities in printing will be shown, or in some cases, performing of printing comes to be impossible.Still further, there is a danger of catching the printing paper in the machine, which results in spending much time in such works as cleaning or checking. When a stencil paper is not mounted on the plate cylinder, the sight which is presented will be such one the operator will entirely be in a deadlock. In addition to this, the loss in the ink in the plate cylinderwill be great. Therefore, in order to prevent such a state, it is always essential that the ink collecting portion be at positions within a prescribed limit below the shaft of the plate cylinder (hereinafter called "prescribed lower positions") statically when the printing machine is at nonprinting state, lest the ink put inside the plate cylinder should ooze out.

Some conventional printing machines of this type have a mechanism which stops the machine by letting the ink collecting portion on the plate cylinder be located at prescribed lower positions at the time when the printing operation has completed, shifting from a printing state to non-printing state, such as when required number of copies have been printed off, when the printing paper put on the delivery board has been out, or when the machine has intentionally been made to stop. Nevertheless, in such a case wherein the plate cylinder is manually made to rotate at non-printing state, the ink collecting portion on the plate cylinder remains at a position occupied after that rotation. Not a printing machine has been provided with a mechanism which automatically corrects to let the ink collecting portion travel to prescribed lower positions.For instance, when a stencil paper is wound on the plate cylinder, it is necessary to rotate the plate cylinder so that the ink collecting portion may be located at upper positions. In such a case, the plate cylinder is often let alone carelessly with the ink collecting portion being at upper positions, which results in causing a nonconformity state of the machine due to drippings of the ink outside the plate cylinder.

The present invention has been made in order to eliminate the disadvantages mentioned above and intends to prevent the machine from coming to be at a nonconformity state which will be caused by drippings of the ink outside the plate cylinder even when the plate cylinder is manually rotated at non-printing state, by permitting the ink collecting portion to travel to prescribed lower positions thereafter.

In order to attain the above-mentioned object, the present invention is characterized in being provided with a detecting means which detects whether an ink collecting portion on a plate cylinder is at prescribed lower positions or not, a clocking means which clocks the time that the ink collecting portion is not at prescribed lower positions at non-printing state, and a driving means which makes the plate cylinder rotate after a prescribed time clocked by the clocking means and permits the ink collecting portion to travel to prescribed lower positions.

Brief description of the drawings Figure lisa perspective view of the plate cylinder portion according to the present invention; Figure 2 is an elevational view in section of the same; Figure 3 is a block diagram of a control means in the plate cylinder; Figure 4 is a block diagram showing a control means of other embodiment; Figure 5 is a schematic elevational view showing a preferred embodiment wherein a safety device is provided; Figure 6 is a schematic elevational view showing another embodiment wherein a safety device is provided; Figure 7 is a block diagram showing a control means of a preferred embodiment which includes a safety device; and Figure 8 is a flow chart.

Detailed description of the invention Referring to the drawings, there will be given explanations of the embodiments of the present invention.

Figures 1 - 3 show the plate cylinder portion of a single cylinder type rotary mimeograph printing machine, wherein a plate cylinder 1 comprises a peripheral portion la and lateral portions 1 b and is of a bottomed cylindrical shape. A shaft 2 passes the plate cylinder at the core portion thereof and is secured to the plate cylinder.An ink oozing-out portion 3 comprising a network having a plurality of small holes is provided at most part of the peripheral portion lain its peripheral direction, whereas an ink collecting portion 4 having no hole or the like is provided at the remaining part of the peripheral portion 1a. A screen 5 made of silk or a synthetic fibre is wound all over the outer periphery of the ink oozong-out portion 3, whereas a belt-like stencilclipping portion 6 is provided on the outer periphery of the ink collecting portion 4 in the axial direction in order to secure the force end of the processed stencil paper.

With reference to Figure 3 particularly, the shaft of the plate cylinder 2 is provided with a driven sprocket 7 and a cam plate 8. The driven sprocket 7 and a driving sprocket 10 secured to the shaft of a motor 9 are connected each other by means of a chain 11 to drive the plate cylinder for rotation. At the same time whether the ink collecting portion 4 is at prescribed lower positions below the shaft of the plate cylinder 2 or not can be detected by the close contact of a circular projecting end portion 8a of the cam plate 8 with a lever 1 2a of a microswitch 12 attached to a bracket (not shown in the drawings) which is secured on the frame side of the printing machine. In this embodiment, it is constructed that an ON signal is produced at the output of the microswitch 12 when the ink collecting portion 4 is at prescribed lower positions.

In Figure 3, 13 is a state-detecting portion which detects whether the printing machine is at a printing state or non-printing state to put out a signal as for the detected result. The state-detecting portion 13 produces an ON signal at the output thereof at a printing state caused by pushing a switch, which is not shown in the drawings, to start the printing operation. When the state in the machine has changed from a printing state to non-printing state, namely, when required number of copies have been printed off, when the printing paper has been out, or when a switch, not shown in the drawings, to stop the printing operation has been pushed, an OFF signal is produced at the output. It is possible to construct properly such a state-detecting portion 13 having such a function by well-known techniques.

The respective outputs of the microswitch 12 and the state-detecting portion 13 are connected with the inputs of a NOR circuit 14. When both of these outputs are off, a timer 15 operates due to the output of the NOR circuit 14. And when the timer 15 has clocked a prescribed time, a motor-driving circuit 16 is operated by the output thereof, whereby the motor 9 will rotate in a prescribed direction. The plate cylinder 1 rotates, accordingly. And when the output of the microswitch 12 comes to be on because of the cam plate 8, the output of the NOR circuit 14 will come to be off to cause the output of thetimer 15to be off, and simultaneously, it resets the timer to stop the motor-driving circuit 16 and the motor 9.

Moreover, signals to perform the ordinary printing operation and for a push-button switch for inching operations are put on the motor-driving circuit 16, although illustration thereof in the drawings is omitted. At a printing state, in spite of the output of the timer 15 being off, the motor-driving circuit 16 operates to drive the motor 9 for the printing operation. At the same time in replacing the stencil paper the plate cylinder 1 can be rotated through inching operations by means of the push-button switch. In place of the inching operations, it is also possible to construct the shaft of the plate cylinder 2 and a manual handle in such a manner that the latter may engage with the former, and the plate cylinder 1 can manually be rotated.

In the embodiment mentioned above, the output of the state-detecting portion 13 is off at non-printing state. If the ink collecting portion 4 is not at prescribed lower positions then, the microswitch 12 comes to be off to cause the output of the NOR circuit 14to be on, then the timer 15 operates to start the motor-driving circuit 16 and the motor 9 after a lapse of a prescribed time, whereby the plate cylinder 1 is made to rotate. When the ink collecting portion 4 has come to be at prescribed lower positions as a result of the rotation of the plate cylinder 1, the microswitch 12 is turned on, which results in that the plate cylinder 1 stops its rotation and the ink collecting portion 4will come to be at prescribed lower positions.In this way at nonprinting state of the printing machine, the plate cylinder 1 rotates itself to let the ink collecting portion 4 travel to prescribed lower positions.

Therefore, if the timer 15 is set to a proper time, for example, to one or two minutes, the ink collecting portion 4 will be allowed to travel to prescribed lower positions before the ink I in the plate cylinder runs out, even when the plate cylinder 1 is manually rotated at non-printing state and the ink collecting portion 4 is located at upper positions. As a result, a nonconformity state of the machine as mentioned above will never be caused.

In the embodiment mentioned above, a cam plate 8 and a microswitch 12 are used as means for detecting the location of the ink collecting portion 4.

In place of them, a slitted disc in combination with a photo-sensor, a magnet in combination with a reed switch, or a magnet in combination with a hall element may be used. In order to prevent overruns caused by inertia of the plate cylinder 1 to increase the accuracy in the probability that the ink collecting portion 4 will stop at prescribed lower positions, it is preferable to construct the machine in such a manner that the rotation-driving to make the ink collecting portion 1 travel to prescribed lower positions is carried out at lower speed than in performing an ordinary printing operation, or through inching operations, in addition to making the machine stop by providing a brake circuit or the like in the motor 9.

Figure 4 is a block diagram showing a control means of other embodiment according to the present invention. The output of the NOR circuit 14 is connected to two timers 15a and 15b. Timers 15a and 1 sub are respectively connected to the motordriving circuit 16 and an alarm sound generator 17 such as a buzzer or the like. The timer 1 spa is set to a time a little longer than that in the timer 1 sub, whereby an alarm sound will be given before the plate cylinder 1 rotates to perform the corrected travelling, so that it is possible to prevent such accidents which are liable to be caused due to a sudden rotation of the plate cylinder 1.In this case, generation of unnecessary noises can be prevented by constructing the alarm sound generator 17 in such a manner that the alarm sound is given only for a prescribed time and intermittently.

Figure 5 shows an embodiment wherein a safety device 18 is provided above and near the plate cylinder 1, in which a travel-inhibiting member 19 is rotatably provided over and close by the plate cylinder 1 so as to cover over the stencil-clipping portion 6 with a shaft for the supporting point 21 secured to a frame 20 being located at an intermediate position thereof. The travel-inhibiting member 19 is provided with a tension spring 22 so as to pull it downward. Another end of the tension spring 22 is attached to a securing pin 23 which is secured to the frame 20. A stopper 24 is secured to the frame 20 lest the travel-inhibiting member 19 should contact to the plate cylinder 1 even at the lowermost position thereof.A travel-inhibiting switch 25 is secured to a bracket (not shown in the drawings) which is secured to the frame 20 at a position where it is brought to ON state when the travel-inhibiting member 19 is at its lowermost position and to OFF state when the travel-inhibiting member 19 is slightly lifted up. Figure 7 is a block diagram showing a control means of a preferred embodiment which includes the safety device 18, wherein the outputs of the timer 15 and the travel-inhibiting switch 25 are connected to an AND circuit 26. The plate cylinder 1 will not start rotating to make correction with respect to its location.

Accordingly, the operator's hand will touch the travel-inhibiting member 19 to let it remain at a sprung-up state with the operator's hand during the mounting work of the stencil paper, so that the travel-inhibiting switch 25 will come to be OFF state, and the plate cylinder 1 is prevented from rotating suddenly. Therefore, the operator can mount the stencil paper free from care.

Moreover, as shown in Figure 6, a machine cover 26a may substitute for the travel-inhibiting member 19. Also in such a case similar effects will be attained, because works are carried out with the machine cover 26a opened in mounting the stencil paper to the plate cylinder, repairing and adjusting or removing the clogged paper.

In the above-mentioned embodiments, the control means is constructed with such hardwares as shown by block diagrams in Figures 3,4 and 7. These hardwares, however, may be varied, where necessary. It is also possible to construct it with softwares in which micro-computers are used. Figure 8 shows an example of flow charts of the programs in such a case. Furthermore, where necessary, it is possible to prove a device to detect clogging of the printing paper and a device to detect whether the stencil paper is set on the plate cylinder or not and it is possible to make the programs include the processing of these detected signals.

As mentioned above, according to the present invention, the plate cylinder will rotate after a lapse of a prescribed time to let the ink collecting portion travel to prescribed lower positions when the ink collecting portion is not at prescribed lower positions at non-printing state. Therefore, even when the plate cylinder is manually rotated by the operator on such an occasion as replacing the stencil paper, the ink collecting portion will thereafter be let to travel automatically to prescribed lower positions, so that it is possible to prevent the ink from going out of the plate cylinder to avoid generation of a nonconformity state of the machine. Accordingly, not only dangers of the machine's being stained or of becoming impossible of printing may be eliminated, but also losses in labours and time for repair as well as such an inconvenience that the machine cannot be used while it is being repaired can be avoided.

Losses in ink is also avoided. In this way costs may be saved.

Claims (5)

1. A single cylinder type rotary mimeograph printing machine characterized in being provided with a detecting means which detects whether an ink collecting portion on a plate cylinder is at prescribed lower positions or not, a clocking means which clocks the time that the ink collecting portion is not at prescribed lower positions at non-printing state, and a driving means which makes the plate cylinder rotate after a prescribed time clocked by the clocking means, and permits the ink collecting portion to travel to prescribed lower positions.

2. A single cylinder type rotary mimeograph printing machine as set forth in claim 1 provided with an alarm means which generates an alarm before the driving means starts.

3. A single cylinder type rotary mimeograph printing machine as set forth either in claim 1 or in claim 2 provided with a safety devide comprising a travei-inhibiting member provided above and near the plate cylinder and a travel-inhibiting switch which operates by the travel of the travel-inhibiting member, wherein the operation of the travelinhibiting switch causes the driving means to stop.

4. A printing machine as claimed in claim 1 and substantially as described with reference to and/or as illustrated in the accompanying drawings.

5. Each and every novel embodiment herein set forth either separately or in combination.