This invention relates to a stencil sheet discharging device of a stencil printing machine, and more particularly, a stencil sheet discharging device of a stencil printing machine in which the discharged stencil sheets fed into a discharged stencil sheet box are compressed by a discharged stencil sheet compression plate and filled in it.
As shown in FIG. 8A, in this type of stencil sheet discharging device in the prior art, a stencil sheet to be discharged is fed into a stencil sheet discharging box 2 by a discharged stencil sheet feeding operation under a state in which a discharging stencil sheet compression plate 1 is positioned at a home position. Upon completion of the discharged stencil sheet feeding operation, the discharged stencil sheet compression plate 1 descends as shown in FIG. 8B to start a compressing operation. At this time, a compression sensor (a photo-interrupter) 3 composed of a light emitting section and a light receiving section is changed from its light receiving state to a light shielding state by a compression sensor plate 5 arranged at a driving shaft 4. In addition, a torque is added to the discharged stencil sheet compression plate 1 from the driving shaft 4 through a coil spring (not shown).
Then, when the discharged stencil sheet compression plate 1 further descends and the compression sensor 3 is changed from the light shielding state to the light receiving state as shown in FIG. 8C, the compression motor is turned off. Then, after elapsing a specified period of time, the discharged stencil sheet compression plate 1 is lifted. At this time, as shown in FIG. 8C, fill-up sensor (a photo-interrupter) 6 comprised of a light emitting section and a light receiving section is shielded against light by a fill-up sensor plate 7.
In turn, as shown in FIG. 8D, when a stencil sheet discharged into the discharged stencil sheet box 2 fills up, the discharged stencil sheet compression plate 1 cannot descend by the discharged stencil sheet. Due to this fact, only the driving shaft 4 (the compression sensor plate 5) is rotated. Accordingly, even if the compression sensor 3 becomes a light receiving state again after it became a light shielding state, the fill-up sensor 6 is not shielded against light by a fill-up sensor plate 7. With such an arrangement as above, it is detected that the discharged stencil sheet box 2 is full of discharged stencil sheets.
The aforesaid stencil sheet discharging device for the stencil printing machine in the prior art can detect by the fill-up sensor 6 that the discharged stencil sheet box 2 is full of stencil sheets. However, this cannot detect the residual amount (vacant capacity) in the discharged stencil sheet box 2. Thus, this device shows a problem that the time required for filling the box with stencil sheets cannot be estimated.
In addition, there occurs occasionally that an operator desires to adjust the fill-up position in the discharged stencil sheet box 2 in reference to its state of use. However, a fixing position of the fill-up sensor 6 in the prior art stencil sheet discharging device for the stencil printing machine must be adjusted. Accordingly, this type of device has a problem that a fixing position of the fill-up sensor 6 cannot be easily adjusted.
Further, in the case that much amount of residual discharged stencil sheets is present in the box 2, all of the discharged stencil sheets is not compressed. Then, as the residual amount of discharged stencil sheet box 2 is reduced, a compression force is gradually applied to each of the discharged stencil sheets. Accordingly, it shows some problems that an appropriate compression force cannot be applied for each of the discharged stencil sheets and a superior compression cannot be carried out.
The present invention has been invented to solve the problems found in the prior art and it is an object of the present invention to reduce the number of sensors for use in sensing the compressing position or the compression force of the discharged stencil sheet compression plate and to reduce cost.
It is another object of the present invention to estimate a time when the box is full of stencil sheets by detecting the residual amount in the discharged stencil sheet box.
It is a still further object of the present invention to adjust a fill-up sensor fixing position in an easy manner.
It is a still yet further object of the present invention to apply a proper compression force for every discharged stencil sheet in the discharged stencil sheet box and to perform a superior compression.
In order to accomplish the aforesaid objects, according to a first aspect of the present invention, there is provided a stencil sheet discharging device for a stencil printing machine comprising:
a discharged stencil sheet compression plate 43 for use in compressing a discharged stencil sheet fed into a discharged stencil sheet box 42 within the discharged stencil sheet box 42;
a driving means (a compression motor 44) for driving the discharged stencil sheet compression plate 43 and compressing the discharged stencil sheet within the discharged stencil sheet box 42;
a compression force detecting means for sensing that a predetermined compression force is added to the discharged stencil sheet;
a control means for stopping a compressing operation performed by the driving means 44 when a predetermined compressive force is detected by said compression force detecting means 50;
a moving amount detecting means for detecting a moving amount of a discharged stencil sheet compression plate 43 when a predetermined compressive force is detected by said compression force detecting means; and
a display means (a discharged stencil sheet amount display unit 94) for displaying a residual amount in the discharged stencil sheet box 42 in reference to a moving amount detected by the moving amount detecting means.
With this stencil sheet discharging device, it becomes possible to estimate a time in which the box is filled with the discharged stencil sheets due to the fact that a moving amount of the discharged stencil sheet compression plate 43 is detected and a residual amount in the discharged stencil sheet box 42 is displayed. In addition, it becomes possible to perform a superior compression and store much amount of discharged stencil sheets in the discharged stencil sheet box 42 due to the fact that every discharged stencil sheet is compressed with a predetermined compression force.
According to a second aspect of the present invention, there is provided a stencil sheet discharging device for a stencil printing machine comprising:
a discharged stencil sheet compression plate 43 for use in compressing a discharged stencil sheet fed into a discharged stencil sheet box 42 within the discharged stencil sheet box 42;
a driving means (a compression motor 44) for driving the discharged stencil sheet compression plate 43 and compressing the discharged stencil sheet within the discharged stencil sheet box 42;
an encoder 50 for generating the number of pulses corresponding to the moving amount of the discharged stencil sheet compression plate 43;
a compression force detecting means for detecting a pulse width of pulse generated from the encoder 50 and detecting that a predetermined compression force is added to the discharged stencil sheet when said pulse width exceeds a predetermined value;
a control means for stopping a compressing operation performed by the driving means 44 when a predetermined compression force is detected by the compression force detecting means;
a moving amount detecting means for counting pulses generated from an encoder 50 until a predetermined compression force is detected by the compression force detecting means and detecting a moving amount of the discharged stencil sheet compression plate in response to the counted number of pulses; and
a display means (a discharged stencil sheet amount display unit 94) for displaying a residual amount in the discharged stencil sheet box 42 in reference to a moving amount detected by the moving amount detecting means.
The invention according to a second aspect of the present invention utilizes one unit of encoder as a sensor for detecting either a compressing position or a compression force of the discharged stencil sheet compression plate as compared with the invention according to a first aspect of the present invention so as to reduce cost of the sensor.
As indicated in a third aspect of the present invention, there is provided a home position sensor 56 for use in sensing a home position of the discharged stencil sheet compression plate 43, the moving amount sensing means either resets or pre-sets the number of pulses to be counted when the home position sensor 56 detects the home position of the discharged stencil sheet compression plate.
Further, as indicated in a fourth aspect of the present invention, there is provided a setting means for setting a compression fill-up position of the discharged stencil sheet box 42, the display means 94 displays the residual amount in the discharged stencil sheet box 42 in response to the compression fill-up position set by the setting means and the moving amount detected by the moving amount detecting means. That is, it is possible to set the compression fill-up position in the discharged stencil sheet box 42 in an easy manner and further the display means 94 can display the residual amount in response to the set fill-up position.
As indicated in a fifth aspect of the present invention, said control means controls said driving means 44 so that said discharged stencil sheet compression plate 43 is operated to compress the discharged stencil sheet within said discharged stencil sheet box 42 until the predetermined compression force is detected by said compression force detecting means, said discharged stencil sheet compression plate 43 is stopped at the compressing position for a predetermined period of time in case where the predetermined compression force is detected by said compression force detecting means, and said discharged stencil sheet compression plate 43 is returned back to the predetermined waiting position, i.e. home position.