JPH058903A - Paper stack bed for printing machine - Google Patents

Abstract

PURPOSE:To provide a printing machine paper stack bed wherein sheet paper can be always surely conveyed and fed, even when the sheet paper is decreased by a paper feed, and further the initial reference position in accordance with thickness of the sheet paper can be easily recognized and set. CONSTITUTION:A thickness side surface of separated sheet paper 10, floated by air from a blow nozzle 6, is detected by two reflecting sensors 21, 22. Since a floated length is different between the cases of thick (A) and thin (B) thickness of the sheet paper, the paper thickness is discriminated in accordance with a light receiving quantity of both the sensors, and an optimum separation condition value corresponding to this discriminated thickness can be recognized. Thereafter, a stack bed, loaded with a sheet paper bundle 2, is lifted so that the light receiving quantity from the sensor 21 is always obtained equal to the optimum separation condition value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper stacking board of a printing machine, and more particularly, to an invention relating to elevation control of the paper stacking board.

[0002]

2. Description of the Related Art An outline of a conventional printing press paper stack will be described with reference to FIG. 13A. A sheet bundle 2 formed by stacking a large number of sheets is stacked on a stacking table 4. Then, the sheets are sequentially conveyed from the uppermost part of the sheet bundle 2 to the printing step, and a predetermined printing process is performed.

The sheet conveying operation is specifically carried out as follows. First, as shown in FIG.
A blowing nozzle 6 is provided near the upper end of the
Air is ejected toward the sheet bundle 2. By blowing this air, several to several tens of sheets above the sheet bundle 2 are floated and separated from the sheet bundle 2 to be separated sheets.
10 are formed. Forming the separation sheet 10 by air ejection in this way prevents adhesion due to static electricity or the like,
This is because only one sheet of paper is surely adsorbed and conveyed and fed to the printing process.

A sheet separate 12 is attached to the upper portion of the blow-off nozzle 6, and the sheet separate 12 is attached.
The uppermost sheet of the separated sheet 10 contacts 12. This prevents the sheets from rising more than necessary and holds the uppermost sheet in a fixed position. A suction foot 14 is located near the upper portion of the separation sheet 10 as shown in the figure. This suction foot 14 first descends in the direction of arrow 92,
The uppermost sheet of the separated sheets 10 is adsorbed and held. Then, after rising in the direction of arrow 91, it moves in the direction of arrow 93 and conveys the sheet to the printing process.

When the sheets are sequentially conveyed and fed, the sheet bundle 2 also decreases accordingly, and the uppermost sheet of the separated sheets 10 does not reach the sheet separate 12. .. As a result, the suction foot 14 cannot properly suck and convey the sheet. For this reason, the stacking table 4 on which the sheet bundle 2 is stacked is lifted in the direction of arrow 91 to prevent the suction failure of the suction foot 14.

Japanese Patent Laid-Open No. 2-33036 discloses a structure for raising the loading platform 4. The outline of the present invention will be described with reference to FIG. 13B. A lower limit sensor 70 is provided near the upper end 78 of the sheet bundle 2.
And an upper limit sensor 71. When the sheet bundle 2 decreases as the sheet is fed, and the upper end 78 of the sheet bundle 2 reaches the lower limit sensor 70, the stacking table 4 starts rising in the direction of arrow 91.
Then, when the upper end portion 78 reaches the upper limit sensor 71, the lifting of the loading platform 4 is stopped. As described above, the stacking table 4 is moved according to the decrease in the number of sheets to prevent the suction failure.

[0007]

The above-mentioned conventional paper stacking machine for printing machines has the following problems. First, in the structure shown in FIG. 13B, the upper end portion 78 of the sheet bundle 2 is the lower limit sensor.
The height of the loading platform 4 is not adjusted unless it is reduced to the position of 70. That is, within the range from the upper limit sensor 71 to the lower limit sensor 70, the number of separated sheets 10 decreases due to sheet feeding,
There is a problem in that it is impossible to effectively prevent a suction failure caused by the suction foot 14 not being able to suck the uppermost sheet.

Further, even if the uppermost sheet is located at a predetermined height, it is properly separated so that the distance between the individual sheets in the separated sheet 10 is not affected by static electricity or the like. There is a need. However, in the structure shown in FIG. 13B, the stacking table 4 is raised without considering the separation state of the separation sheet 10. For this reason, there is a problem in that a sheet feeding failure such as double sheet feeding occurs and a stable sheet feeding operation cannot be performed.

Further, the conventional printing press paper loading platform has the following problems. Sheets having various paper thicknesses are prepared, and the mass per sheet differs depending on the paper thickness. Due to such a difference in mass, the floating height when air is blown also differs.
That is, when the paper thickness is relatively thick and heavy, it does not rise so much, whereas when the paper thickness is thin and light, it rises high.

For this reason, the sheet height of the sheet bundle 2 is 20 (see FIG. 13).
It is necessary to set A) in advance to different initial reference positions according to the paper thickness. Fig. 12 shows the relationship between the paper thickness and the initial reference position. The sheet height 20 of the sheet bundle 2 shown in FIG. 12A is set to the initial reference position K1, and the uppermost sheet of the separation sheet 10 comes into contact with the sheet separate 12 to form a proper separation state. There is.

On the other hand, when the sheet is relatively thick, as shown in FIG. 12B, the sheet height 20 is set to the initial reference height K2.
Set to. That is, in this case, since the sheet is relatively heavy and difficult to float, the uppermost sheet of the separated sheet 10 does not reach the sheet separate 12 unless the paper height 20 is set high. On the other hand, when the sheet thickness is relatively thin, lower the sheet height 20 as shown in FIG. 12C, and set the initial reference height K3.
Set to. If the paper height 20 is set to a high position, a thin sheet will float too much and fly beyond the sheet separate 12.

Conventionally, the setting of the initial reference height according to the sheet thickness of the sheet has been performed manually while visually confirming before the sheet feeding operation. Further, when setting the initial reference height, the setting adjustment must be performed while taking into consideration that the distance between the sheets in the separated sheet 10 is in the optimum separated state. Therefore, it takes a lot of time to prepare the paper, and this visual adjustment requires skill.
There is a problem that the initial reference height cannot be easily set.

Therefore, according to the present invention, even if the number of sheets decreases due to sheet feeding, the sheets can be always conveyed and fed reliably, and the initial reference position corresponding to the sheet thickness of the sheets can be set. It is an object of the present invention to provide a printing press paper loading platform that can be easily recognized and set.

[0014]

According to a first aspect of the present invention, there is provided a printing press paper stack comprising a drive device for raising or lowering the stack based on an ascending signal or a descending signal, and a stack of a plurality of sheets. , A sheet bundle to be loaded on the stacker, an air jetting part that floats and separates the upper sheet of the sheet bundle by air jet, a printing process of the uppermost sheet of the separated sheets In a paper stacker of a printing machine equipped with a transport section for transporting to each other, irradiation light is emitted to two or more side surfaces of different thickness of a sheet separated by air ejection, and each reflected light from the side surface of thickness is received. Two or more thickness detectors that respectively output the thickness light reception signals, a paper thickness detection unit that detects the paper thickness of the sheet based on the difference between the thickness reception signals from the two or more thickness detectors, and the paper thickness detection Based on the paper thickness of the sheet detected by the method, the optimum Optimal separation state value determining means for determining the state value, irradiating the thickness side surface portion of the sheet separated by the air jet with irradiation light, receiving reflected light from the thickness side surface portion, and outputting a separation state reception signal Separation state detector, taking in the separation state light reception signal and the optimum separation state value, and adjusting the platform to output the rising signal or the falling signal to the drive device so that the separation state light receiving signal and the optimum separation state value are always equal It is characterized by having means.

[0015]

In the paper stacking base of the printing machine according to the first aspect, the two or more thickness detectors irradiate irradiation light onto two or more side surfaces of different thickness of the sheet separated by the air jet. Then, each reflected light from the side surface of the thickness is received and a thickness received light signal is output. Each of these thickness light reception signals is given to the paper thickness detection means, and the paper thickness of the sheet is detected based on the difference between the light reception signals.

Here, the floating height from the air ejection source in the length direction of the sheet differs due to the difference in sheet thickness of the sheet, that is, the difference in weight. Therefore, the paper thickness of the sheet can be easily and accurately recognized by obtaining the difference between the light reception signals from two or more thickness detectors. Then, the optimum separation state value determining means determines the optimum separation state value based on the paper thickness of the sheet.

Further, in the paper stacker of the printing machine according to the first aspect, the separation state detector irradiates the thickness side surface portion of the sheet separated by the air jet with the irradiation light and reflects the light reflected from the thickness side surface portion. The light is received and the separated state light reception signal is output. Then, the stack adjustment means fetches the separated state light receiving signal and the optimum separated state value, and outputs an ascending signal or a descending signal to the driving device so that the separated state light receiving signal and the optimum separated state value are always equal.

Therefore, the separation state light receiving signal and the optimum separation state value are constantly adjusted to be equal by raising and lowering the stack.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A printing machine paper stack according to an embodiment of the present invention will be described with reference to the drawings. First, FIG. 1 shows the overall structure of the printing press paper loading platform. A sheet bundle 2 formed by superposing a large number of sheets is stacked on a stacking table 4. This loading platform 4 is driven by a hoist motor 8 as a driving device.
It is designed so that it can be raised and lowered freely through the chain 16.
The continuously variable transmission 32 controls the lifting operation of the hoist motor 8,
Various command signals are transmitted from the control device 31 to the continuously variable transmission 32 through lines L3, L4, and L5.

The sheets are conveyed to the printing process one by one from the highest one of the sheet bundle 2 and subjected to the printing process. This transportation is performed by the suction foot 14 which is a transportation portion performing a predetermined movement to suck the sheet (see FIG. 13A). Further, in order to prevent the sheets from adhering to each other due to static electricity or the like, air is ejected from the ejection nozzle 6 as an air ejecting portion, and the upper sheet is lifted to form a separated sheet 10 (FIG. 13A). reference). Note that the uppermost sheet is brought into contact with the sheet separate 12 provided on the upper part of the blow-out nozzle 6, so that the floating height of the sheet is regulated (see FIG. 13A).

The air ejected from the blow-out nozzle 6 is
It is supplied through the air hose 60. Then, the proportional flow rate control valve 61 provided in the air hose 60 supplies or stops air by opening and closing. The proportional flow rate control valve 61 is opened / closed by a proportional flow valve opening signal transmitted from the control device 31.

In the vicinity of the suction foot 14 or the sheet separate 12, as shown in FIG. 1, there is a photoelectric sensor 2 which is a thickness detector.
1, 22 are provided. The photoelectric sensors 21 and 22 are reflection type sensors, and irradiate the side surface of the separation sheet 10 floated by the blowing nozzle 6 with irradiation light. This state is shown in FIG. 7A.
Shown in. Light emitted from the photoelectric sensor forms detection areas M1 and M2 and is reflected by the thickness side surface of the sheet to generate reflected light. Then, the reflected light is received by the photoelectric sensors 21 and 22, respectively, and the received light signal is captured by the control device 31 through the lines L1 and L2. When many sheets are located in the detection areas M1 and M2, the amount of reflected light also increases and the amount of received light increases.

The detailed structure of the controller 31 will be described with reference to FIG. The control device 31 includes a ROM 41, a CPU 42, and an RA.
The M42 is provided, and the CPU 42 controls each unit according to the program stored in the ROM 41. Input interface
Lines L1 and L2 provided with amplifiers 48 and 49 and A / D converters 46 and 47 and line L6 are connected to 44. On the other hand, the output interface 45 includes a line L3 provided with a D / A converter 52, a D / A converter 50 and an amplifier 51.
Is connected to the line L8 and lines L4, L5, and L7. The lines L3, L4, and L5 receive the rotation speed setting signal, the forward rotation signal, and the reverse rotation signal from the CPU 42 in the continuously variable transmission 32.
Send to. The continuously variable transmission 32 has a structure as shown in FIG. 3, and controls the forward and reverse rotation directions and the rotation speed of the hoist motor 8. Since the structure of the continuously variable transmission 32 is publicly known, detailed description thereof will be omitted.

This paper stacker of the printing press performs a paper feed preparation operation before the paper feed operation of the sheet for the printing process is started. Flow charts of this preparatory operation in the programs stored in the ROM 41 are shown in FIGS. The preparation operation is started by the input of the initial signal (step S2), and first, the received light signal from the photoelectric sensor 21 is taken in and the measured value is obtained (step S4). Then, based on this measured value, the paper surface height 20 of the sheet bundle 2 is adjusted and set to the lower limit position of the detection areas M1 and M2 as shown in FIG.

That is, while determining whether or not the measured value is "0" (steps S5, S7, S9), the forward rotation signal or the reverse rotation signal is output to move the loading platform 4 in the arrow 91 or 92 direction at low speed. It is moved up and down (steps S6 and S8), and the paper surface height 20 of the sheet bundle 2 is positioned at the lower limit of the detection areas M1 and M2. At the time of this position adjustment, air is not ejected from the blow-out nozzle 6 and the separated sheet 10 is not formed.

The sheets are abundantly prepared in various thicknesses so as to meet various printing purposes. After completing the position setting in steps S2 to S7,
The paper thickness of each of the sheets stacked on the stacker 4 is detected. This detection operation will be described following step S10 in FIG. CPU 42 is an output interface 45
Sends a proportional flow valve open signal to the proportional flow rate control valve 61 from line L8 (step S10, see FIGS. 1 and 2). Upon reception of the proportional flow valve opening signal, the proportional flow control valve 61 opens the valve, blows air from the blow-out nozzle 6 to float the sheet, and forms the separated sheet 10. FIG. 7 shows this state.

Here, if the sheet thickness of the sheet is different, the weight per sheet is different, and the floating height in the length direction of the arrow 94 is different depending on the sheet thickness of the sheet. Occurs.
FIG. 7A shows the case of a relatively thin sheet, and each sheet is highly floated in the direction of arrow 94 from the blowing nozzle 6 which is the air jet source.

On the other hand, FIG. 7B shows the case of a relatively thick sheet, and the flying height of the sheet in the length direction is lower than that in FIG. 7A. Since the flying height in the length direction is different in proportion to the paper thickness of the sheet in this way, the number of sheets located in each of the detection areas M1 and M2 is also different. That is, the paper thickness of the sheet can be recognized by detecting the magnitude of the measurement value of the light reception signals from the photoelectric sensors 21 and 22 and the combination of both measurement values.

Therefore, in step S12, the photoelectric sensor 2
The received light signals from 1 and 22 are fetched as measured values, and these output currents are collated with the data table shown in FIG. 8 to determine the paper thickness (step S14). This data table is stored in the ROM 41 in advance. In FIG. 8, for example, when the amount of light received by the photoelectric sensor 21 is Ai and the output from the photoelectric sensor 22 is Bj, it is determined that the sheet thickness of the sheet is Cji.

When the paper thickness of the sheet is recognized in this way,
At the same time, the optimum separation state of the separated sheets 10 and the optimum sheet height of the sheet bundle 2 during the sheet feeding operation.
20 is also determined. The optimum separation state and the optimum paper surface height 20 are as follows. In order for the suction foot 14 to adsorb the sheets and sequentially convey them to the printing process properly, the uppermost sheet of the separated sheets 10 is the sheet separate 12
It is necessary that the sheets are located in contact with each other and that the individual sheets of the separation sheet 10 are separated at appropriate intervals.
If the uppermost sheet does not reach the sheet separate 12, the suction by the suction foot 14 is not performed, and the separation sheet 10
This is because if the respective sheets are close to each other, a plurality of sheets will be conveyed due to static electricity or the like, and a paper feed failure will occur.

By the way, the mass per sheet varies depending on the sheet thickness of the sheet, and the floating height when air is blown also varies. That is, when the paper thickness is relatively thick and heavy, it does not rise so much, whereas when the paper thickness is thin and light, it rises high. Therefore, it is necessary to adjust the paper surface height 20 to a different height according to the paper thickness to create an optimum separation state.

That is, the optimum paper surface height and the optimum separation state are specifically as shown in FIG. When the paper thickness is thick, it is difficult for the paper to float, so it is necessary to increase the paper height 20 (see FIG. 12B). On the other hand, when the paper thickness is thin, it easily floats up. Therefore, when the paper surface height 20 is high, the sheets are overlapped in the vicinity of the sheet separate 12 and are not separated. Therefore, when the paper thickness is thin, it is necessary to reduce the paper height 20 as shown in FIG. 12C.

The optimum separation state corresponding to such a paper thickness is stored in the ROM 41 together with the data table shown in FIG. 8 (not shown). When the paper thickness is detected based on the outputs of the photoelectric sensors 21 and 22, the optimum separation state value corresponding thereto is selected and determined as the target value and stored in the RAM 43 (step S16). The optimum separation state value is
It is a measurement value that should be output from the photoelectric sensor 21 when the paper surface height 20 and the separated state of the separated sheet 10 are optimal.

At the time when the target value is determined, the stack 4 on which the sheet bundle 2 is stacked remains in the state set to the height shown in FIG. Therefore, the received light signal from the photoelectric sensor 21 is taken in as a measured value and compared with the target value (steps S20 and S22), and the loading platform 4 is moved up and down to adjust the position (steps S24 and S26). When the target value and the measured value match, the CPU 42
A paper feed start signal is output to the printing process through L7 to start the paper feed operation (step S28).

The above is the preparatory operation before paper feeding. After that, the sheets are sequentially conveyed and fed to the printing process. Next, the operation of the paper stack of the printing machine during the paper feeding operation will be described. Now, suppose that the sheet feeding operation is started with the state shown in FIG. 9A as the optimum paper surface height and the optimum separation state. As the uppermost sheet in the separated sheets 10 is sequentially conveyed, the number of sheets decreases and the state shown in FIG. 9B is obtained. That is, 10 separate sheets of paper
The number of sheets in
Optimal separation is lost.

The change in the separated state is detected by the photoelectric sensor 21. That is, as compared with FIGS. 9A and 9B, the number of sheets in the detection area M1 decreases in proportion to the reduction of the number of sheets due to the paper feeding operation. Therefore, the amount of light reflected from the side of the thickness of the sheet is also reduced. This decrease in the amount of reflected light will appear as a decrease in the measured value from the photoelectric sensor 21, and a mismatch will occur between the measured value and the target value.

When the measured value and the target value are deviated from each other in this way, the CPU 42 controls the output interface 45 and the line L.
The forward rotation signal and the rotation speed setting signal are output to the continuously variable transmission 32 through 4 and L5. Then, the rotation speed of the hoist motor 8, that is, the rising speed of the stacking table 4, is adjusted by following the decrease speed of the paper surface height 20 due to the decrease of the sheets.
Always maintain optimum paper height and separation. That is, the target value and the measured value are constantly compared, and the rising speed of the loading platform 4 is adjusted faster or slower so that the measured value follows the target value. The rotation speed of the hoist motor 8 is the line
It is transmitted from the CPU 42 to the continuously variable transmission 32 as a rotation speed setting signal via L3.

FIG. 10 shows the relationship between the decreasing speed of the sheets and the rising speed of the stacker 4. In FIG. 10A, the sheet height 20 of the sheet bundle 2 decreases at the speed Vd0 as the number of sheets due to the sheet feeding decreases. Then, this decrease of the sheet is detected as a decrease in the amount of reflected light in the detection area M1, and the hoist motor 8
Raises the platform 4 at a speed Vh0. Here, the speed Vd0
Is equal to the speed Vh0, and the paper surface height 20 of the sheet bundle 2 is maintained constant at the position X0 and stabilized. That is, the measurement value in the detection area M1 in this case is adjusted to be the target value K0.

However, the printing operation or the like may be accelerated in the printing process, and in such a case, the paper feeding speed is fast, and accordingly, the descending speed of the sheet height 20 of the sheet bundle 2 is fast. That is, at time t0 in FIG.
0 decreases at the speed Vd0, but if the paper feeding speed increases at the time t1 after the elapse of T seconds, the speed of the decrease increases to Vd1 (FIG. 10B). The ascending speed of the loading platform 4 at this time is Vh1 (Vh1 <Vd1), and there is a difference in V1 between them. In this case, the number of sheets in the separated sheet 10 decreases in proportion to the position decrease of the paper surface height 20, and the value from the detection area M1 also becomes the measured value K1.
Change to (K1 <K0).

However, according to the adjustment of the ascending speed of the loading platform 4 in this embodiment, even if the descending velocity of the paper height 20 changes as shown in FIGS. 10A to 10B, the loading platform 4 follows this. Can rise. The operation of calculating and determining the rising speed of the loading platform 4, that is, the rotation speed of the hoist motor 8 is illustrated.
It will be described based on the flowchart of 11.

First, the CPU 42 obtains a measured value K1 from the photoelectric sensor 21 via the line L1 from the photoelectric sensor 21 (see FIG. 2) (step S50). Then, the speed difference V1 between the descending speed Vd1 and the ascending speed Vh1 is obtained based on the measured value K1 (step S52). This calculation is performed by the following formula.

V1 = (X0-X1) / (t1-t0) = a. (K0-K1) / T .. Note that X0 is the position of the paper surface height at time t0, which is the same as the optimum paper surface height. , X1 is the position of the paper surface height at time t1, K0 is the measured value from the photoelectric sensor 21 at time t0, K1 is the measured value from the photoelectric sensor 21 at time t1,
a is a constant of proportionality between the paper height and the measured value, and T is the time from t0 to t1.

Thus, the speed difference V1 at time t1 is obtained. Then, first, this speed difference V1 is added to the ascending speed Vh1 at the time t1 (step S54). As a result, the descending speed of the paper surface and the ascending speed of the loading platform 4 can be balanced. However, since the paper surface height has already dropped to X1 at the time t1, it is impossible to return the paper surface height to X0 as it is. Therefore, in order to return the paper surface height to X0 at time t2 (time t1 + T), the speed difference V1 is added again in step S56.
Note that C in step S56 is a correction coefficient for correcting the response delay of the hoist motor. The speed V obtained in step S56 is the rising speed from time t1 to time t2.

The rotation speed setting signal Vm is calculated based on the rising speed V thus obtained (step S58). Here, “g” is a constant representing the rotation reduction ratio of the hoist motor 8. Then, the rotational speed setting signal Vm is output to the continuously variable transmission 32 through the line L3 (step S60).
The above-described operation (steps S50 to S60) is repeated every T seconds, and the stacking table 4 is raised while following the lowering of the paper surface height 20.

It should be noted that the descending speed of the paper surface height 20 is constant,
When there is no deviation from the rising speed of the loading platform 4, the speed difference V1 is set to "0" and the above calculation is performed.
If the paper height 20 is higher than the reference position X0, that is, if the rising speed of the loading platform 4 is faster, the speed difference V1 is calculated as a negative value.

In this embodiment, since one of the two or more thickness detectors is used as the separation state detector, it is not necessary to separately provide the separation state detector. Therefore, the cost can be reduced.

In the above embodiment, during the paper feeding operation, the light receiving signal from the photoelectric sensor 21 is used as the measured value and the ascending speed of the loading platform 4 is determined based on the measured value. May determine the speed. Further, the rising speed can be calculated by using the light receiving signals of both the photoelectric sensors 21 and 22 as the measured values. When both light receiving signals are used, the ascending movement of the loading platform 4 can be performed more accurately.

As a method of raising the loading platform 4 by following the lowering speed of the paper surface height 20, in addition to the calculation shown in FIG. 11, the difference between the lowering speed of the paper surface height 20 and the lifting speed of the loading platform 4 is calculated. If the value is negative, the rotation speed of the motor may be increased, and if the value is positive, the rotational speed may be decreased. With such a configuration, feedback control can be performed with a simpler structure.

[0049]

In the paper stacker of the printing press according to the first aspect of the present invention, the paper thickness of the sheet can be easily and accurately recognized, and the optimum separation state value determining means can determine the paper thickness of the sheet. Based on this, the optimum separation state value is determined. Then, the separation state light receiving signal from the separation state detector is adjusted to be equal to the optimum separation state value.

Here, since the separated state light receiving signal changes according to the sheet surface height of the sheet bundle, by adjusting the separated state light receiving signal and the optimum separated state value equally, the optimum value according to the paper thickness is obtained. It is possible to always maintain a good separation state. That is, it is possible to reliably convey and feed sheets,
Feeding failure can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall structure of a printing press paper loading platform according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a detailed configuration of a control device in FIG.

3 is a circuit diagram showing a detailed configuration of the continuously variable transmission in FIG.

FIG. 4 is a flowchart showing a paper feed preparation operation for a printing process.

FIG. 5 is a flowchart showing a paper feed preparation operation for a printing process.

FIG. 6 is a diagram showing a state in which the sheet height of the sheet bundle is adjusted and set to the lower limit position of the detection area.

FIG. 7 is a diagram showing a state in which air is ejected from a blowing nozzle to float a sheet to form a separated sheet, where A is a thick sheet and B is a thin sheet. It is a figure which shows the case of.

FIG. 8 is a diagram showing the contents of a data table stored in a ROM.

FIG. 9 is a diagram showing a reduction of sheets due to a paper feeding operation,
FIG. 8A is a diagram showing an optimum state before the start of sheet feeding work, and FIG. 9B is a diagram showing a state in which the number of sheets has decreased due to sheet feeding.

FIG. 10 is a diagram showing the relationship between the descending speed of the sheet height and the ascending speed of the stacking table 4 due to the reduction of the sheets, where A is the descending speed and the ascending speed are equal, and B is the descending speed and the ascending speed. It is a figure which shows the case where it is earlier.

FIG. 11 is a flowchart showing an operation of calculating and determining a rising speed of a loading platform, that is, a rotation speed of a hoist motor.

FIG. 12 is a diagram showing a relationship between paper thickness and an initial reference position, B shows a case where the sheet thickness of the sheet is thicker than A, and C shows a case where the sheet thickness is thinner than A.

FIG. 13 is a diagram showing an outline of a conventional printing press paper loading platform.

[Explanation of symbols]

 2 ... Sheet bundle 6 ... Blow-off nozzle 8 ... Hoist motor 14 ... Adsorption foot 21, 22 ... Photoelectric sensor 31 ... Control device 32 continuously variable transmission

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location B65H 3/48 320 Z 9148-3F

Claims (1)

Claim: What is claimed is: 1. A drive device for raising or lowering a stack based on an ascending signal or a descending signal, a sheet constituted by superposing a plurality of sheets and stacked on the stack. Printing with a bundle, an air ejection part that floats and separates the upper sheet of the sheet bundle by air ejection, and a transport part that conveys the uppermost sheet of the separated sheets to the printing process In the machine stacker, two or more different thickness side surfaces of a sheet separated by air jet are irradiated with irradiation light, each reflected light from the thickness side surface is received, and a thickness reception signal is output respectively. Paper thickness detection means for detecting the paper thickness of the sheet based on the difference between the thickness detection signals from the above thickness detectors, two or more thickness detectors, and the paper thickness of the sheet detected by the paper thickness detection means The optimal component that determines the optimal separation state value based on State value determination means, Separated state detector that emits irradiation light to the thickness side surface of the sheet separated by air ejection, receives reflected light from the thickness side surface, and outputs a separation state light reception signal, separation state A stacking adjustment means for taking in the received light signal and the optimum separation state value and outputting a rising signal or a falling signal to the drive device so that the separation state light receiving signal and the optimum separation state value are always equal. Characteristic printing machine paper loading platform.