JPS6244454A - Printing press - Google Patents

Abstract

PURPOSE:To perform the adjustment of a printing position with high accuracy, by counting the output pulse of an angle-of-rotation detection part for detecting the unit angle rotation of a blanket cylinder from the time when the output of a reference position detection part is generated, and starting the driving of a paper feed pawl driving motor at the point of time when the count value has reached a printing position indicating value. CONSTITUTION:The relation among the rotational speed of a stepping motor 28, a reference position pulse B and a home position detection signal C is set so that the value between the point of time t1 when a pulse B generates and the point of time t2 when the stepping motor 28 begun to rotate corresponds to a printing position indicating value; a printing position is changed on the basis of the count value of an angle-of-rotation pulse A before the driving of the motor 28 is started from the point of time when the pulse B generates. Because the start of paper feed is made earlier, the generation of the detection signal C is set to the point of time t3. Because paper feed operation is performed on the basis of the pulse A detecting the unit angle rotation of a blanket cylinder 1, a speed controller is adjusted to make it possible to always perform accurate printing corresponding to the printing position indicating value.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a printing machine using a rotary plate cylinder type, and in particular enables high-accuracy variation of the printing position during printing operation, as well as adjustment of paper feeding operation. This relates to a printing machine with improved repeatability.

[Prior art]

Conventionally, when printing relatively large amounts of thick card paper such as business cards or postcards, offset printing machines using a rotary plate cylinder system have been used.

Here, the above-mentioned offset printing machine has a plate cylinder around which a rigid plate is wound, a blanket cylinder to which the plate cylinder is pressed and rotated, and an impression cylinder which rotates by pressing the printing paper against the blanket cylinder. When the main motor rotates the blanket cylinder, a plate cylinder and an impression cylinder which are connected to the blanket cylinder through gears are also rotated. Then, if the ink is uniformly supplied by the ink roller after water is supplied to the stamp wrapped around the blanket cylinder, the non-printing part of the rigid plate is hydrophilic, so the ink will stick only to the printed part. and is transferred to the peripheral surface of the blanket cylinder. Next, when card paper is supplied as printing paper between the blanket cylinder and the impression cylinder, the card paper is pressed against the blanket cylinder by the impression cylinder, so that the ink adhering to the peripheral surface of the blanket cylinder is removed. The image is transferred to the surface of the card and printed.

Here, the paper feeding device sequentially feeds the card paper between the blanket cylinder and the impression cylinder, and the paper feeding claw is reciprocated by driving a cam mechanism connected to the blanket cylinder. It is configured to sequentially push out the card papers stored in the printing paper stocker from the bottom side.

[Problem that the invention seeks to solve]

However, since the printing press having the paper feeding mechanism described above uses a cam mechanism to drive the paper feeding claw back and forth, the paper feeding position relative to the blanket cylinder is semi-fixed. As a result, in order to adjust the printing position relative to the printing paper, it is necessary to correct the rotational position of the plate cylinder relative to the blanket cylinder, but this work must be performed after the printing operation has stopped for a while, so it is extremely difficult to do so. It becomes a complicated work. On the other hand, it is conceivable to provide a paper feed position adjustment mechanism in the cam mechanism, but the structure would be extremely complicated, making it unsuitable as a paper feed mechanism for a small and simple printing machine.

In addition, in the paper feeding device with the above configuration, the paper feeding mechanism is connected to the rotating shaft of the blanket cylinder via a chino and a cam mechanism is used, so the repeatability of the paper feeding operation is low. (As a result, there is a problem in that the printing position shifts, resulting in color shift during color overlapping printing.

[Means for solving problems]

Therefore, the printing press according to the present invention is provided with a rotation angle detection section that generates a pulse every unit angle rotation of the blanket cylinder, and a reference position detection section that detects a reference point of the blanket cylinder, and a pulse is generated from the rotation angle detection section. Counting the pulses in the central processing control unit from the time when the output of the reference position detection unit is detected, and when this counted value matches a designated print position value set according to the print position, starts driving the stepping motor, The paper feed pawl located at the home position is moved back and forth to return it to the home position again. The stepping motor is driven by frequency-dividing the pulses generated from the multiplier that multiplies the output pulses of the rotation angle detector into a value specified by the central processing controller to generate narrow pulses. The stepping motor is rotated in one step according to the output of the frequency division section, and the central processing control section shifts the address every time the output of the frequency division section is generated to read the contents of the memory in which the frequency division value table is stored. The rotation speed characteristic of the stepping motor is controlled to have a trapezoidal shape by supplying the read value to the frequency dividing section as a frequency division value.

In addition, the central processing control section controls the stepping motor so that the speed is the lowest at the number of feeding steps that are slightly before the home position when the paper feed claw retreats, and an output signal is generated from the home position detection section. Control 4 is performed to stop the rotation of the stepping motor at this point.

[Effect]

In a printing press configured in this way, the output pulses of the rotation angle detection section are counted from the time when the output of the reference position detection section is generated until reaching the specified print position value set according to the print position. Since this starts the stepping motor for driving the paper feed claw, the print position can be changed with high precision even during printing by simply changing the setting of the print position designation value. It turns out. Furthermore, since a cam mechanism and a chain connection a mechanism are not used as in the past, the accuracy of paper feeding is greatly improved, and color misregistration during color overlapping printing is prevented.

Furthermore, since the speed of the stepping motor is controlled in a trapezoidal manner, step-out is prevented and the reliability of the paper feeding operation by the stepping motor can be measured. Also,
When the paper feed claw retreats, the rotation speed of the stepping motor is set to the lowest speed at the number of feed steps that are slightly before the home position, and stop control is performed when the home position is detected. This makes it possible to always stop the paper feed claw at the home position even if the paper goes out of step.

〔Example〕

FIG. 1 is a side view of essential parts of an embodiment of a printing press according to the present invention, in which a blanket cylinder 1 is rotatably supported between chassis (not shown). This blanket cylinder 1 is constructed by a check 73 being hung between a gear (not shown) attached to the rotating shaft and a gear (not shown) attached to the rotating wheel of the main motor (AC induction motor) 2. , is designed to be rotated in the direction of the arrow. Note that 4 is a speed control section that controls the rotational speed of the main motor 2. Further, the upper rear side and the lower side of the blanket cylinder 1 are supported by eccentric shafts 5 and 6, and as the eccentric shafts 5 and 6 rotate during the printing mode, the peripheral surface of the blanket cylinder 1 is A plate cylinder 7 and an impression cylinder 8 are provided, which are pressed against the plate cylinder 7 and the impression cylinder 8. And this plate cylinder 7
A rigid plate (not shown) is wrapped around the circumferential surface of the holder to hold it. Further, a rotation detection section 9 is provided on the rotation axis of the blanket cylinder 1. For example, as shown in FIG. 2, this rotation detection section 9 includes a rotation angle detection section 12 consisting of a rotary encoder 10 and an optical sensor 11, a slit disk 13 having one slit, and an optical sensor 14. The reference position detecting section 15 is comprised of a reference position detecting section 15. Reference numeral 16 denotes a paper feeding mechanism, and a table 17 is provided horizontally along the tangent between the blanket cylinder 1 and the impression cylinder 8. And this table 17
A plurality of grooves are provided in a part of the blanket cylinder l and the impression cylinder 8 in a direction tangential to each other, that is, along the paper feeding direction, and a slider 18 that moves integrally within these grooves is mounted. ing. Here, the slider 18 extends from the table 1 after a portion slightly retreated from the end in the paper feeding direction.
The paper feed pawl 19 is constituted by a stepped portion that protrudes from 7, and the amount of protrusion thereof is about 172 mm with respect to the paper thickness of the card as printing paper, which will be described later. The front part of the paper feed claw 19 of the slider 18 is inclined downward to guide the card, and a plate 20 extending rearward is provided at a part of the rear end. Thus, when the slider 18 is located at the home position, the light from the optical sensor 21 is blocked. In other words, the plate 20 and the optical sensor 21 constitute the home position detection section 22.

23 is a box-shaped printing paper stocker, and the side wall of one example of the blanket cylinder has a gap approximately 1.5 times the thickness of the card 24 stored therein between the table 17 and the paper stocker 23.
A gate 23a is formed between the card and the surface of the card to eject cards one by one. Also,
A notch 25 is provided at the lower end of the side wall of the printed paper stocker 23 on the rear side in the paper feeding direction, and forms a recess for the slider 18 . Reference numeral 26 denotes a timing pulley provided at the lower portion of the leading end of the table 17 in the paper feeding direction, and 27 represents a stepping motor 28 with a gear reduction configuration provided at the lower portion of the rear end of the table 17 in the paper feeding direction.
The timing pulley is mounted on the rotating shaft of the timing belt 29, and a timing belt 29 is passed between the timing pulleys 1726 and 27. An arm 18a extending downward from the slider 1 is fixed to a part of the timing belt 29. Reference numeral 30 denotes a control section, which controls the rotation of the stepping motor 28 by inputting output signals of the rotation angle detection section 12, reference position detection section 13, and home position detection section 22 that constitute the rotation detection section 9. Control paper feed operation. here,
As shown in FIG. 3, the control section 30 has a multiplication section 31 that multiplies the rotation angle pulse A output from the rotation angle detection section 12. This multiplier 31 first doubles the frequency by a doubling circuit 31a, focusing on the fact that the duty of the rotational angle pulse A is exactly 50 due to the slit provided in the rotary encoder lO. . This is because when the duty of the input signal is 50, it is possible to easily generate pulses synchronized with the rise and fall of the input signal using a simple circuit using an integrating circuit and a gate circuit. This doubler circuit 3
This is used to stabilize the operation by lowering the multiplier of the phase-locked loop circuit (hereinafter referred to as PLL circuit) 33 that follows 2. As is generally known, the PLL circuit 33 is a voltage controlled variable frequency oscillator (hereinafter referred to as VCO) 3.
3a, a frequency divider 33b that divides the output signal of this VCO 33a by n, and an output signal of this frequency divider 33b and an output signal of the doubler circuit 32, and output a signal according to the phase difference between them. It is constituted by a phase comparator 33C that supplies a frequency control signal to the VCO 33a. Therefore,
If the frequency of the rotation angle pulse A is fo, then the doubler circuit 3
The frequency of the pulse generated from 2 is 2fo, and PL
The frequency of the pulse generated from the L circuit 33 is 2nf0. Here, the frequency divider 3 in the PLL circuit 33
If the frequency division value n of 3b is 32, the multiplier 31 will generate a pulse obtained by multiplying the rotation angle pulse A by 64. Next, reference numeral 34 is a central processing control section configured with a microcomputer, and the rotation angle pulse A generated from the optical sensor 11 constituting the rotation angle detection section 12 via the input ports P+ to P3, the reference position detection section. The reference position pulse B generated from the optical sensor 14 constituting the home position detecting section 15 and the home position detection pulse C generated from the optical sensor 21 constituting the home position detecting section 22 are inputted respectively. Reference numeral 35 denotes a keyboard, which is used to set the paper feed position, that is, the print position, based on the generation position of the reference position pulse B, and input the input key to the central processing control unit 34.
supply to s. Reference numeral 36 denotes a read-only memory (hereinafter referred to as ROM) in which stepped frequency division values for performing slow start and slow down control for the stepping motor 28 are stored as a frequency division value table, and the central processing control The frequency division value at the address specified by the address signal supplied from the output port 01 of the section 34 is read out and supplied to the input port P4. 37 is a programmable counter as a variable frequency divider, which is internally set by reading the frequency division value output from the output port 0□ of the central processing control unit 34 using the load signal output from the output port 03; Every time the count value of the pulse signal supplied from the multiplier 31 reaches the frequency division value, an output pulse E is generated and the output pulse E is output to the input capacitor 1- of the central processing control unit 34.
Supply to P6. Reference numeral 38 denotes a drive circuit which drives the stepping motor 28 one step in response to the motor drive signal F generated from the output port 04 of the central processing control section 34 every time the pulse signal E is generated from the programmable counter 37. Rotate by one minute. Note that the central processing control unit 34 receives the pulse signal E from the programmable counter 37.
The read address for the ROM 36 is shifted every time the ROM 36 is generated.

In the printing press configured in this manner, when a power switch (not shown) is turned on, the main motor 2 rotates in the right direction at a speed according to an instruction from the speed control section 4.

The rotation of the main motor 2 is transmitted to the rotating shaft of the blanket cylinder 1 via the chino 3, thereby rotating the blanket cylinder 1 in the right direction, and also rotating the plate cylinder 7 and the impression cylinder which are connected by gears. 8 rotates to the left.

However, at this point, the plate cylinder 7 and the impression cylinder 8 are separated from the blanket cylinder I by the eccentric shaft 5.6 and are in a printing standby mode.

On the other hand, the rotation detecting section 9 attached to the rotating shaft of the blanket cylinder 1 detects the rotary encoder 10 and the slit disc 1 shown in FIG. 2 simultaneously with the rotation of the blanket cylinder 1.
3 rotates, the optical sensor 11 constituting the rotation angle detection section 12 generates a rotation angle pulse A of duty-50 for each unit angle rotation of the blanket cylinder 1, and also constitutes the reference position detection section 15. The optical sensor 14 generates a reference position pulse B every time it detects the slit 13a provided in the slit disk 13. However, the position of the slit 1-13a provided on the slit disk 13 is at the forefront of printing on the blanket cylinder 1 or in front of it.

Note that the control unit 30 is inactive in the print standby mode.

Next, the card 2 as printing paper is placed in the printing paper stocker 23.
The paper setting is completed by accommodating the paper 4 and placing the way I-23b. Then, when a printing start switch (not shown) is turned on, the eccentric shafts 5 and 6 are rotated by a plunger (not shown), so that the plate cylinder 7 and the impression cylinder 8 are pressed against the peripheral surface of the blanket cylinder 1 and rotated. Here, water and ink are uniformly supplied to the stamp wrapped around the plate cylinder 7 by a water supply roller and an ink roller (not shown), so that ink is applied only to the printed portion of the plate, as is generally known. It will stick. The ink adhering to the stamp is transferred onto the circumferential surface of the blanket cylinder 1 as the plate cylinder 7 rotates.

Next, in the print mode, the control section 30 starts operating. Hereinafter, the circuit operation of FIG. 3 showing a specific example of the control section 30 will be explained using the flowchart shown in FIG. 4. First, in the circuit shown in FIG. 3, a doubling circuit 32 constituting the multiplier 31 doubles the rotation angle pulse A of the duty-50 supplied from the rotation angle detecting section 12 of the rotation detecting section 9. This generates 2to pulses. Here, since the duty to the input rotation angle pulse is 50, the doubler circuit 32 bidirectionally differentiates the input signal using a generally well-known simple circuit configured by a combination of an integrating circuit and a gate circuit. By multiplying the signal by two, the number of multipliers applied to the PLL circuit 33 at the subsequent stage is reduced, and the operation is made to run more smoothly. Next, PLL circuit 3
In No. 3, the frequency divider 33b rotates the output pulse D of the VCO 33a by one minute and then supplies it to the phase comparator 33c. The phase comparator 33c compares the phase of the pulse supplied from the doubler 32 and the pulse supplied from the frequency divider 33b, and supplies a signal with a level corresponding to the phase difference to the VCO 33a as a frequency control signal. , VCO3
3a generates a pulse signal that is synchronized with the input pulse signal and multiplied by n times. In other words, when the frequency division value n of the frequency divider 33b is set to 32, the rotation angle pulse A is multiplied by 64 times and a pulse signal is generated from the multiplier 31, so that the rotation of the blanket cylinder 1 can be performed with higher accuracy. will be detected.

Next, when the print mode is started, the central processing control unit 34
The process starts and moves to step Sl shown in FIG.

In step S1, the number of prints specified by operating the ten keys provided on the keyboard 35 is set. Next, in step S2, the keyboard 3
After printing start position data is set in an up/down counter that counts the operations of the up/down keys provided at step S3, the process moves to step S3. In step S3, the judgment becomes No and the process waits by repeating the judgment until the reference position pulse B is supplied to the input port P2, and when the reference position pulse B is supplied, the judgment becomes YES and the process proceeds to step S4. Move to. In step S4, after counting the rotational angle pulses A, the process moves to step S, and it is detected whether the counted value in step S4 matches the print start position data set in step S2. Here, if the determination in step S5 is NO, the operation of returning to step S4 is repeated. If the determination in step S is YES, the process moves to step S6, where the address counter in the reset state is incremented by one count. Next, in step S7, by supplying the address signal specified by the address counter counted up in step S6 to the ROM 36, the value stored in the corresponding address of the frequency division value table is read out. , in step SIl, the output port 03 of the central processing control section 34
By outputting a write signal from , the frequency division value read in step S7 is set in the programmable counter 37 as a variable frequency divider. Therefore, the programmable counter 37 sequentially counts the pulse signals generated by the multiplier 31, and when the counted value reaches a preset value, generates the pulse signal E and supplies it to the input port Pb. Next, in step s9, the pulse signal E
It waits by repeating operations until the pulse signal E is generated, and when the pulse signal E is supplied, the determination becomes YES and the process moves to step S1. Step 3
In 1G, the drive circuit 38 is connected from the output port 04.
By supplying a stepping motor drive signal to , the stepping motor 28 is driven one step in the normal rotation direction. In this case, assuming that the slider 18 is stopped at the home position, that is, at a position where the plate 2o blocks the light from the optical sensor 21, one step of the stepping motor 28 drives the timing pulley 27 after being decelerated by the gear. Therefore, the timing belt 2 that is passed between the timing pulley 26 and
9 causes a slight movement to the left.

Next, in step Sl+, the home position detection signal C is supplied from the optical sensor 21 constituting the home position detection section 22 to the input port P3, that is, the home position detection signal e changes from "H" to "L". It is determined that it returns to . Here, the stepping motor 28
The rotation moves the slider 18 forward, that is, the plate 17
Since it is in the direction away from the optical sensor 21, the determination in step S becomes No and the operation returns to step S6 and is repeated. Then, in step S6, since the address counter is incremented by 1 each time the operation is repeated, the readout addresses stored in the ROM 36 are sequentially shifted, so that the frequency division value table is sequentially read out. It is preset every time the output signal E is generated in the programmable counter 37.

Here, the values of the frequency division value table stored in the ROM 36 are, for example, 277.234, 206, 186°171.159.
,150,142...67.66°65.64
, 64, 64, 64..., the stepping motor 28 will first step by 1 after counting the pulse signal generated from the multiplier 31 by 277, and then step by 1 after counting by 234. It will be stamped. In this case, the multiplier 31 increases the rotation angle pulse A by 6
Since the speed is multiplied by 4, the stepping motor 28 gradually increases its speed from extremely slow rotation.
At the point when the frequency division value reaches 64, the stepping motor 28 takes one step for every one pulse of the rotation angle pulse A, reaching the maximum speed, and the stepping motor 28
The rotational speed characteristic of No. 8 is as shown in FIG. 5 between time points t1 and t2, and slow start control can be performed. Then, the frequency division value 64 as the minimum frequency division value is added to the frequency division value table.
is set over a predetermined step, and then sequentially increasing frequency division values are set in subsequent steps, and as shown in FIG. 5, time 1. -Stepping motor 28 as shown in 13
The speed characteristic is trapezoidal, that is, slow start/slow down control can be performed, thereby preventing step-out when the stepping motor 28 is used for paper feeding.

When the stepping motor 28 is driven to rotate in this manner, the slider 8 shown in FIG. 1 is guided by the table 17 and moved from the home position in the paper feeding direction. Then, when the rotation of the stepping motor 28 reaches its maximum speed, the paper feed claw 19 comes into contact with the card 24 and presses it in the paper feeding direction. In this case, the paper feed claw 19
protrudes from the surface of the table 17 over a range less than or equal to the thickness of the card 24 (for example, 1/2), so only one card 24 is pressed. Furthermore, the gate 23a provided between the front side wall of the printing paper stocker 23 and the surface of the table 17 is
Since the dimensions are wider than the thickness of one card and narrower than the thickness of two cards (for example, 1.5 times the thickness of the card 24), the cards 24 are pushed out one by one and connected to the blanket cylinder 1. It is supplied between the impression cylinder 8 and the impression cylinder 8.

Here, since the circumferential speeds of the blanket cylinder 1 and the impression cylinder 8 are set slightly faster than the maximum sheet feeding speed by the slider 18, the leading edge of the card 24 is fed between the blanket cylinder 1 and the impression cylinder 8. Then, the ink adhering to the circumferential surface of the blanket cylinder 1 is transferred to the surface of the card 24 as it is pressed against the surface of the card 24, thereby completing printing. Note that since the amount of movement of the slider 18 corresponds to the amount of step drive for the stepping motor 28, it is necessary to set the frequency division table so that the maximum number of repetitions occurs when the paper feed claw 19 contacts the card 24. Needless to say. Next, if the slider 18 is stopped by decelerating just before the number of steps reaching the leading edge, after switching the rotation direction for the stepping motor 28, the frequency division value table for the return direction is sequentially addressed. As a result, the frequency division value is changed every step of the stepping motor 28 to perform slow start/slow/down control to move the slider 18 backward. And optical sensor-2
1 is a plate 2 provided at the rear end of the slider 18
When 0 is detected, a home position detection pulse C is generated and supplied to the input port Pz of the central processing control section 34. Then, the determination in step S11 shown in FIG. 4 is YES.
As a result, the process moves to step S1□, so the driving of the stepping motor 28 is stopped and the slider 18 is stopped at the home position. In step S12, the output signal of a switch (not shown) that detects the card 24 sent out from the game card 23a is counted, and the process proceeds to step S13. In step SL3, the number of printed sheets counted in step S1□ is determined in step S1
If the result is No, it is assumed that the number of printed sheets is insufficient and the operation returns to step S2. Also,
If the determination in step S13 is YES,
It is assumed that printing of the target number of sheets has been completed and the process is stopped.

Here, the rotation speed of the stepping motor 28.

The relationship between the reference position pulse B and the home position detection signal C is shown in FIG. Therefore, the value between the rotation start time t2 of the stepping motor 28 shown in FIG. The paper feeding position, that is, the printing position, will be changed depending on the number of rotation angle pulses A counted up to this point.For example, if the printing position designation value is decreased, the stepping motor 2
As shown in FIG. 6 (dl), the rotation characteristic of No. 8 is that the rotation start point of the stepping motor 28 approaches the generation point of the reference position pulse B, and the printing position moves toward the rear end of the card 24 in the paper feeding direction. In addition, since the start of paper feeding is brought forward, the return of the slider 18 to the home position is also brought forward, and the generation of the home position detection signal C is as shown at time t3 in FIG. 6(e). Become.

Since this paper feeding operation is based on the rotation angle detection pulse B that detects the unit angular rotation of the blanket cylinder L, even if the speed controller 4 is adjusted and the printing speed is varied, these operations will not occur. The relationship does not change at all, and printing can always be performed accurately at the position corresponding to the print position designation value. Here, Fig. 6 (a), (d)
In the rotational characteristics of the stepping motor 28 shown in FIG. 2, by setting the frequency division value to the maximum immediately before the slider 18 reaches the home position, the rotation of the stepping motor 28 remains at the lowest speed, and the home position is detected. It is stopped by signal C, but this means that if the stepping motor 28 goes out of step for some reason, it will stop before the home position and the next paper feed operation will malfunction. This is to prevent

In the above embodiment, the rotation angle detection section 12 . Although only the case where the reference position detecting section 15 and the home position detecting section 22 have an optical configuration has been described, it goes without saying that other principles such as magnetism may be used. Furthermore, in the above embodiment, the rotation angle pulse A was counted to control the printing start position, but by counting the output signal of the multiplier circuit 31 or the output signal of the doubler circuit 32, This allows for more precise adjustment of the print start position.

〔Effect of the invention〕

As explained above, the printing press according to the present invention has a rotation angle that detects unit angular rotation of the blanket cylinder mounted on the rotation shaft of the blanket cylinder from the time of output generation of the reference position detection unit mounted on the rotation shaft of the blanket cylinder. The output pulses of the detection unit are counted, and when the counted value reaches the specified print position value, the stepping motor for driving the paper feed claw starts to be driven, so it is necessary to set the specified print position value. By simply varying the printing position, the printing position can be changed with high precision even during printing. In addition, since the paper feed pawl is directly driven by a stepping motor, it prevents the repeatability from decreasing when using a chain linkage mechanism and cam mechanism as in the past. This prevents color shift when performing overlapping color printing. Furthermore, since the speed of the stepping motor is controlled in a trapezoidal manner, step-out is prevented and the reliability of the paper feeding operation can be measured. In addition, when the paper feed claw retreats, the rotation speed of the stepping motor is set to the lowest speed at the number of feed steps slightly before the home position, and stop control is performed when the home position is detected. Even if you fall out of step due to some reason,
The paper feed claw has various excellent effects such as being always accurately stopped at the home position.

[Brief explanation of the drawing]

FIG. 1 is a main part configuration diagram for explaining one embodiment of a printing press according to the present invention, FIG. 2 is a side view showing a specific example of the rotation detection section shown in FIG. 1, and FIG. 3 is a diagram similar to that shown in FIG. 1. 4 is a flowchart showing the operation of the circuit shown in FIG. 3, FIG. 5 is a diagram for explaining trapezoidal speed control of a stepping motor, and FIG. al～(el
2 is a waveform diagram showing the relationship between the rotational speed characteristics of the stepping motor, the reference position pulse B, and the home position detection pulse C. FIG. DESCRIPTION OF SYMBOLS 1...Blanket cylinder, 2...Main motor, 4...Speed controller, 5.6...Eccentric shaft, 7...Print cylinder, 8...Impression cylinder, 12...Rotation angle Detection unit, 15... Reference position detection unit, 16... Paper feeding mechanism, 18... Slider, 19... Paper feeding claw, 22... Home position detection unit, 28... Stepping motor, 30... Control unit, 31... Multiplier unit, 32... Double multiplier circuit, 33... Phase lock loop circuit (PLL circuit), 34... Central processing control unit, 35... Keyboard, 36...Read-only memory (ROM), 37...
- Programmable counter (frequency divider), 38...drive circuit. Patent applicant Shinano Kenshi Co., Ltd. Agent Patent attorney Tai 1) Akihiro, %″゛1 layer bi

Claims (5)

[Claims] (1) A blanket cylinder that is rotationally driven by a main motor, a printing plate is wrapped around its circumferential surface, and is rotated by being connected to the rotating shaft of the first blanket cylinder, and the printing plate is pressed against the circumferential surface of the first blanket cylinder. The plate cylinder to which the ink adhering to the printed part is transferred is connected to the rotating shaft of the former blanket cylinder and rotates.
An impression cylinder that presses the supplied printing paper against the blanket cylinder for printing, and a paper feed claw that pushes out the printing paper stored in the printing paper stocker and supplies it one sheet at a time between the blanket cylinder and the impression cylinder. a rotation angle detection section that generates a rotation angle pulse for each unit angle rotation of the blanket cylinder; a reference position detection section that detects a reference position of the blanket cylinder; and a home position of the paper feed claw. The rotation angle detection pulses are counted from the time of detection of the reference position pulse generated by the home position detection unit to be detected, the stepping motor that drives the paper feed pawl, and the reference position detection unit, and this counted value is the print position. When the specified value is reached, the stepping motor is started to be driven, and its rotational speed characteristic is changed to a trapezoidal shape to advance the paper feed pawl, and the step number is driven to reach the forward end. If so, the stepper motor is characterized by being constituted by a control section that executes control to switch the rotation direction, change the rotation speed characteristic back to a trapezoidal shape, and stop the rotation of the stepping motor when an output from the home position detection section is generated. printing machine. (2) The printing press according to claim 1, wherein the stepping motor has a gear reduction mechanism. (3) The control unit includes a multiplier that multiplies the rotation angle pulse, a memory that stores a frequency division value table for changing the rotational speed characteristic of the stepping motor into a trapezoidal shape, and a multiplier that multiplies the output pulse of the multiplier. The rotation angle pulse is counted from the time of detection of the reference position pulse generated from the variable frequency divider and the reference position detection section, and when the counted value reaches the specified print position value, the frequency division value table is stored in the memory. and setting a frequency division value in the variable frequency divider, and when a frequency division output is generated from the variable frequency divider, reading out the next address of the frequency division value table and setting it in the variable frequency divider. is repeated, and when the frequency division value of the number of steps in which the paper feed claw reaches a predetermined forward end is read out, an output signal is generated from the central processing control unit that commands direction reversal and the variable frequency divider. a driver circuit that drives the stepping motor one step in response to a step drive signal supplied from the central processing control unit each time the motor moves, and reverses the rotational direction of the stepping motor according to instructions from the central processing control unit. A printing machine according to claim 1, characterized in that: (4) When the central processing control unit reaches the number of steps immediately before returning to the home position, the central processing unit continues to specify to the variable frequency divider a frequency division value that causes the rotational speed of the stepping motor to reach a predetermined minimum speed. 4. The printing machine according to claim 3, wherein the paper feed claw is ensured to return to its home position when the stepping motor is out of step. (5) The multiplier circuit is a doubling circuit that doubles the frequency by bidirectionally differentiating the rising and falling portions of the rotation angle pulse with a duty of 50, and a phase-locked loop that multiplies the output of this doubling circuit by n times. 4. The printing machine according to claim 3, characterized in that the printing machine is constituted by a circuit.