FORM 2
THE PATENTS ACT, 1970 (39 of& 1970) THE PATENTS RULES, 2003 [SCeOeM PsLeEcTtEi oSnP E1C0I,F IRCuAlTeI O1N3 ] CAM CURVE GENERATION METHOD, CAM CURVE GENERATION DEVICE,
CONTROL DEVICE, TRANSPORT DEVICE, PRINTER, CUTTER, AND
BAG MAKING MACHINE;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED
AND EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
5
2
DESCRIPTION
Field
[0001] The present invention relates to a cam curve
5 generation method for generating an electronic cam curve, a
cam curve generation device, a control device, a transport
device, a printer, a cutter, and a bag making machine.
Background
10 [0002] A bag making machine such as a sheet cutter using
a shearing mechanism, or a printing machine that performs
letterpress printing needs to repeat an operation of
transporting a sheet and stopping the sheet in position.
The bag making machine or the printing machine drives a
15 transport roller by a servo system in order to control the
cutting position or the printing position with high
accuracy. Transport of the sheet is interrupted on the
basis of a reference mark printed on the sheet so as to
correct a misalignment of the cutting position or the
20 printing position due to a slip between the sheet and the
roller (see, for example, Patent Literature 1). A
transport roller for sheets is often driven by electronic
cam control in accordance with an electronic cam curve.
[0003] Because a sheet needs to stop during a cutting or
25 printing operation, the transport roller
accelerates/decelerates before and after the stop of the
sheet. Upon detection of the mark printed on the sheet,
the transport roller interrupts transport of the sheet and
stops.
30
Citation List
Patent Literature
[0004] Patent Literature 1: Japanese Patent Application
3
Laid-open No. 2017-226128
Summary
Technical Problem
5 [0005] In detecting the mark printed on the sheet for
the purpose of interrupting transport of the sheet, the
rotational amount of the transport roller before detection
of the mark is changed in the presence of a slip between
the sheet and the transport roller. For this reason, there
10 are variations in the speed of the transport roller at the
start of interrupt as the mark is detected at different
timings. As a result, a problem of variations in the
coasting amount of the sheet from the timing at which the
mark is detected to the stop of the transport roller arises,
15 which leads to variations in the eventual stop position,
that is, the cutting position or the printing position.
[0006] The present invention has been achieved to solve
the above problems, and an object of the present invention
is to obtain a cam curve generation method for generating
20 an electronic cam curve that can reduce variations in the
coasting amount of a sheet at the time of interrupt.
Solution to Problem
[0007] In order to solve the above problems and achieve
25 the object, the present invention provides a cam curve
generation method for generating an electronic cam curve
showing a relation between a movement distance of a
workpiece and a rotational angle of a main shaft that is a
control reference for electronic cam control. The present
30 invention generates the electronic cam curve to allow
repetition of an operation of moving the workpiece and, on
a basis of interrupt processing of electronic cam control,
stopping the workpiece, the interrupt processing occurring
4
during movement of the workpiece, the electronic cam curve
allowing the workpiece to move at a constant speed during a
set period including a point in time when the interrupt
processing occurs at each stroke termination of the
5 repeated operations.
Advantageous Effects of Invention
[0008] The cam curve generation method according to the
present invention has an effect of generating the
10 electronic cam curve that can reduce variations in the
coasting amount of the sheet at the time of interrupt.
Brief Description of Drawings
[0009] FIG. 1 is a diagram illustrating a configuration
15 of a bag making machine according to a first embodiment of
the present invention.
FIG. 2 is a block diagram illustrating a functional
configuration of the bag making machine according to the
first embodiment.
20 FIG. 3 is a diagram illustrating an electronic cam
curve and a speed waveform according to the first
embodiment.
FIG. 4 is a first flowchart for explaining operation
of the bag making machine according to the first embodiment.
25 FIG. 5 is a first timing chart for explaining
operation of the bag making machine according to the first
embodiment.
FIG. 6 is a second flowchart for explaining operation
of the bag making machine according to a second embodiment
30 of the present invention.
FIG. 7 is a second timing chart for explaining
operation of the bag making machine according to the second
embodiment.
5
FIG. 8 is a diagram illustrating a hardware
configuration of a computer system that implements cam
curve generation devices according to the first and second
embodiments.
5
Description of Embodiments
[0010] A cam curve generation method, a cam curve
generation device, a control device, a transport device, a
printer, a cutter, and a bag making machine according to
10 embodiments of the present invention will be described in
detail below with reference to the accompanying drawings.
The present invention is not limited to the embodiments.
[0011] First embodiment
FIG. 1 is a diagram illustrating a configuration of a
15 bag making machine 10 according to a first embodiment of
the present invention. The bag making machine 10 includes
a transport roller 2, a mark detector 3, a printing unit 5,
a cutting unit 6, and a control device 100. The transport
roller 2 is a transport unit to transport a sheet 1 that is
20 a workpiece. The mark detector 3 is a detection unit to
detect a mark 4 printed in advance on the sheet 1. The
printing unit 5 includes a stamp to make a print on the
sheet 1. The cutting unit 6 cuts the sheet 1. The control
device 100 controls those units. The sheet 1 is in the
25 form of plural bag-like sheets connected with one another
through connection portions thereof. The cutting unit 6 is
defined by a shearing mechanism using a shearing cutter.
The transport roller 2, the mark detector 3, and the
control device 100 define a transport device. This
30 transport device and the printing unit 5 define a printer.
This transport device and the cutting unit 6 define a
cutter. The cutter, excluding the printing unit 5, may be
regarded as the bag making machine 10. The cutting unit 6
6
cuts the sheet 1 at the connection portions to thereby
produce plural bags.
[0012] When the mark detector 3 detects the mark 4, the
control device 100 immediately stops the transport roller 2.
5 After the stop of the movement of the sheet 1, the control
device 100 causes the cutting unit 6 to cut the sheet 1 and
causes the printing unit 5 to make a print on the sheet 1
during the stop of movement of the sheet 1. The control
device 100 controls movement of the sheet 1 by electronic
10 cam control using an electronic cam curve described later.
[0013] FIG. 2 is a block diagram illustrating a
functional configuration of the bag making machine 10
according to the first embodiment. FIG. 2 illustrates the
configuration of the control device 100 in detail, but
15 omits the sheet 1. The control device 100 includes servo
motors 121, 151, and 161, servo amplifiers 122, 152, and
162, and a controller 200 that is a control unit.
[0014] The servo motor 121 drives the transport roller 2.
The servo motor 151 drives the printing unit 5. The servo
20 motor 161 drives the cutting unit 6. The servo amplifier
122 controls the servo motor 121. The servo amplifier 152
controls the servo motor 151. The servo amplifier 162
controls the servo motor 161. The controller 200 and the
servo amplifiers 122, 152, and 162 are connected in the
25 form of a daisy chain as illustrated in FIG. 2. The
controller 200 executes electronic cam control on the servo
amplifiers 122, 152, and 162. This electronic cam control
causes the transport roller 2, the printing unit 5, and the
cutting unit 6 to operate in synchronization with a virtual
30 main shaft that is the control reference. In the
electronic cam control, an electronic cam curve shows a
relation between the rotational angle of the main shaft and
a movement distance of a workpiece. When the mark detector
7
3 detects a mark marked on the sheet 1, the mark detector 3
outputs a detection result to the controller 200. The
controller 200 controls the servo amplifier 122 on the
basis of the electronic cam curve and the detection result
5 output by the mark detector 3, such that the transport
roller 2 is driven and controlled. Similarly, the
controller 200 drives and controls the printing unit 5 and
the cutting unit 6 by the electronic cam control. The
controller 200, which has a function of a cam curve
10 generation device, can generate an electronic cam curve for
the controller 200 to execute electronic cam control on the
transport roller 2. A personal computer located outside
the control device 100 may generate an electronic cam curve
and then transmit the generated electric cam curve to the
15 controller 200. The controller 200 may include motion
controllers that each execute electronic cam control on a
corresponding one of the servo amplifiers 122, 152, and 162,
and a programmable controller that controls the motion
controllers.
20 [0015] The controller 200 or the personal computer
located outside the control device 100 functions as the cam
curve generation device. The cam curve generation device
generates a constant-rate-feed electronic cam curve to be
described below. The constant-rate-feed electronic cam
25 curve refers to an electronic cam curve that defines cyclic
or repeated operations of the transport roller 2 moving the
sheet 1 that is a workpiece and stopping the sheet 1 in
position. The controller 200 controls the transport roller
2 by using the electronic cam curve. FIG. 3 is a diagram
30 illustrating an electronic cam curve 71 and a speed
waveform 72 according to the first embodiment. The
horizontal axis of both graphs in FIG. 3 represents the
main shaft angle (x). The vertical axis of the lower graph
8
illustrating the electronic cam curve 71 represents a sheet
movement amount (y) that indicates a movement distance of
the sheet 1. The vertical axis of the upper graph
illustrating the speed waveform 72 represents a sheet speed
5 that is the movement speed of the sheet 1. The main shaft
angle is a rotational angle of the virtual main shaft that
is the control reference for the electronic cam control.
Shifting the main shaft angle by a cam cycle completes
single-stroke processing. For simplicity, the cam cycle is
10 herein defined as equal to 360°. Through the single-stroke
processing, the bag making machine 10 cuts a single bag
from the sheet 1 into a finished product. In FIG. 3, the
electronic cam curve shows the relation between the main
shaft angle and the movement distance of the sheet 1 that
15 is a workpiece. The movement distance of the sheet 1 is
proportional to the rotational amount of the transport
roller 2. Accordingly, the electronic cam curve is also
regarded as showing the relation between the main shaft
angle and the rotational amount of the transport roller 2.
20 A value obtained by differentiating the sheet movement
amount with respect to time is defined as a sheet speed.
Assuming that the value of the main shaft angle is
proportional to time, a value obtained by differentiating
the sheet movement amount with respect to the main shaft
25 angle may be defined as a sheet speed. The following
descriptions are based on the assumption that the value of
the main shaft angle is proportional to time. The
rotational speed of the transport roller 2 corresponds to
the sheet speed and is thus proportional to the sheet speed.
30 A stroke termination 73 in FIG. 3 provides a given period
including a point in time at which the sheet 1 stops in
position, and the sheet speed, that is, the rotational
speed of the transport roller 2 is a constant value in that
9
given period. That is, in accordance with the electronic
cam curve in FIG. 3, the sheet 1 that is a workpiece is
moved at a constant speed during the above-described given
period. The above-described given period is set to include
5 the point in time at which the mark detector 3 detects the
mark 4 and interrupt processing of the electronic cam
control occurs in the controller 200 of the control device
100. As described later, upon the occurrence of the
interrupt processing of the electronic cam control, the
10 sheet 1 that is a workpiece stops. Thereafter, the
operation of moving the sheet 1 and stopping the sheet 1 is
repeated. In order to set the above-described given period,
the fluctuation range of movement distance of the sheet 1
is estimated on the basis of the position of the mark 4
15 printed in advance on the sheet 1 to thereby calculate the
range of the value of main shaft angle within which the
mark detector 3 can reliably detect the mark 4. Then, the
above-described given period is set so as to include a
period corresponding to that calculated range.
20 [0016] In FIG. 3, reference sign “S” represents a
transport stroke that is the sheet movement amount in
single-stroke processing, and reference sign “Vc”
represents a creep speed that is the sheet speed which has
become lower at the stroke termination 73 for the
25 positioning of the sheet 1. Also, reference sign “S1”
represents a movement distance of the sheet 1 before the
sheet speed becomes the creep speed Vc, and reference sign
“L1” represents a main shaft angle at which the sheet speed
becomes the creep speed Vc. Therefore, L1 and S1 are set
30 such that interrupt processing of the electronic cam
control occurs within a range where the movement distance
of the sheet 1 exceeds S1, that is, a range where the main
shaft angle exceeds L1.
10
[0017] The electronic cam curve is a curve of degree n,
which is represented by a polynomial having the sheet
movement amount (y) defined by the main shaft angle (x),
where the sheet movement amount (y) is a cam output and the
5 main shaft angle (x) is a cam input. The electronic cam
curve is expressed by equation (1) below. In equation (1),
A0, A1, •••, An are coefficients.
[0018]
[Equation 1]
10 ••• (1)
[0019] The gradient of the electronic cam curve
represented in equation (1) is expressed by equation (2)
below.
[0020]
15 [Equation 2]
••• (2)
[0021] As described above, the (x, y) coordinates of the
point at which the sheet speed changes to the creep speed
Vc are represented as (L1, S1). Accordingly, the
20 coordinates (L1, S1) are defined as a boundary condition
and then substituted into the equation (1). Consequently,
the following equation (3) is obtained.
[0022]
[Equation 3]
25 ••• (3)
[0023] Substitution of the condition that the sheet
speed becomes the creep speed Vc when the main shaft angle
is L1 into equation (2) results in equation (4) below.
[0024]
30 [Equation 4]
11
••• (4)
[0025] The controller 200 or the personal computer
located outside the control device 100 can calculate the
coefficients A0, A1, •••, An by solving the simultaneous
5 equations defined by equations (3) and (4) with further
added conditions such as a condition that the transport
stroke becomes S and an initial acceleration condition of
the sheet speed. The number n of coefficients is limited
by the number of given conditions. The coefficients A0, A1,
10 •••, An calculated in this manner are given to the
controller 200, so that the controller 200 obtains an
electronic cam curve expressed by equation (1) such that
the sheet speed at the stroke termination 73 is maintained
at a constant creep speed Vc that is a target value.
15 [0026] FIG. 4 is a first flowchart for explaining
operation of the bag making machine 10 according to the
first embodiment. FIG. 5 is a first timing chart for
explaining operation of the bag making machine 10 according
to the first embodiment. In FIG. 5, the horizontal axis
20 represents the main shaft angle, while the vertical axis
represents the transport roller speed. The transport
roller speed is a rotational speed of the transport roller
2 which is proportional to the sheet speed.
[0027] In accordance with the electronic cam curve
25 obtained in the manner as described above, the controller
200 in the control device 100 controls and drives the
transport roller 2 to thereby start transporting the sheet
1 (Step S11). When the mark detector 3 detects the mark 4
(Step S12), interrupt processing occurs in the controller
30 200 (Step S13). Upon the occurrence of interrupt
processing in the controller 200, the transport roller 2
12
stops and then the sheet 1 stops after a lapse of a given
coasting time T (Step S14). In accordance with the above
electronic cam curve, the controller 200 controls the
transport roller speed at the stroke termination 73 to
5 bring the transport roller speed to a constant value for
the coasting time T such that the sheet speed becomes the
creep speed Vc. As a result, even in the presence of
variation in the timing at which the mark 4 is detected,
the coasting amount of the sheet 1 for the coasting time T
10 after the interrupt processing is constant without varying.
[0028] After transport of the sheet 1 stops at Step S14,
the controller 200 causes the cutting unit 6 to start
cutter operation at a given main shaft angle (Step S15).
The transport roller 2 is set to stop at a preset value of
15 the main shaft angle even if the mark 4 is not detected.
It is possible to preset such a main shaft angle that the
cutting unit 6 starts cutter operation after transport of
the sheet 1 completely stopped. At Step S15, the cutting
unit 6 starts cutter operation at the preset main shaft
20 angle. A closed state of the shearing cutter is that a
shearing cutter of the cutting unit 6 is located at a
cutter closed position or lower. When the shearing cutter
of the cutting unit 6 is closed (Step S16), a cut is made
on the sheet 1. A preset period illustrated by the
25 rectangular waveform in FIG. 5 is defined as a cutter
closed period. When the cutter closed period ends, the
shearing cutter moves up. From the value of an encoder of
the servo motor 161, the controller 200 checks that the
shearing cutter is opened (Step S17). As a certain amount
30 of time is required for the shearing cutter to be closed
from a fully-opened state, a dead time during which neither
sheet transport nor cutting is performed is provided from
Step S14 at which the transport roller 2 stops and thus
13
transport of the sheet 1 stops to Step S16 at which the
shearing cutter is closed. A description of operation of
the printing unit 5 is omitted as the printing unit 5 makes
a print on the sheet 1 during the above cutter closed
5 period.
[0029] Second embodiment
The bag making machine 10 according to a second
embodiment of the present invention has a configuration
identical to that illustrated in FIG. 1, and also has a
10 functional configuration identical to that illustrated in
FIG. 2.
[0030] FIG. 6 is a second flowchart for explaining
operation of the bag making machine 10 according to the
second embodiment of the present invention. FIG. 7 is a
15 second timing chart for explaining operation of the bag
making machine 10 according to the second embodiment. In
FIG. 7, the horizontal axis represents the main shaft angle,
while the vertical axis represents the transport roller
speed.
20 [0031] The cutting unit 6 having a shearing cutter like
the bag making machine 10 may start its operation at any
time so long as transport of the sheet 1 is completed
before the shearing cutter is closed, such that the sheet 1
stops at the point in time of the closing of the shearing
25 cutter. For this reason, an earlier start of the operation
of the shearing cutter than that of the first embodiment
makes it possible to further reduce the dead time. An
electronic cam curve to be used by the controller 200 for
controlling the transport roller 2 in the second embodiment
30 is the same as the electronic cam curve according to the
first embodiment except that the operation timing of the
cutting unit 6 is early as compared to the first embodiment.
[0032] In accordance with the electronic cam curve
14
obtained in the manner as described in the first embodiment,
the controller 200 in the control device 100 controls and
drives the transport roller 2 to thereby start transport of
the sheet 1 (Step S11). Thereafter, the controller 200
5 causes the cutting unit 6 to start cutter operation at a
given main shaft angle (Step S15). As described also in
the first embodiment, the transport roller 2 is set to stop
at a preset value of the main shaft angle even if the mark
4 is not detected. A required time for the shearing cutter
10 to come into a closed state after the start of cutter
operation is known in advance. Therefore, to the extent
that the sheet 1 completely stops at the point in time of
the closing of the shearing cutter, the start of the cutter
operation can be so earlier as to precede the stop of the
15 transport of the sheet 1 than that of the first embodiment.
Specifically, the main shaft angle, at which the cutter
operation starts at Step S15, is set to an angle greater
than an angle obtained by subtracting a change in the main
shaft angle from the main shaft angle at which the
20 transport roller 2 stops, the change in the main shaft
angle being necessary from the start of the cutter
operation to closure of the sheering cutter,.
[0033] When the mark detector 3 detects the mark 4 (Step
S12), interrupt processing occurs in the controller 200
25 (Step S13). Upon the occurrence of interrupt processing in
the controller 200, the transport roller 2 stops and then
transport of the sheet 1 stops after a lapse of a given
coasting time T (Step S14). In accordance with the above
electronic cam curve, the controller 200 controls the
30 transport roller speed at the stroke termination 73 to
bring the transport roller speed to a constant value for
the coasting time T such that the sheet speed becomes the
creep speed Vc. As a result, the coasting amount of the
15
sheet 1 for the coasting time T is constant without varying.
[0034] After transport of the sheet 1 stops at Step S14,
the shearing cutter of the cutting unit 6 is closed during
the stop of transport of the sheet 1 (Step S16), such that
5 cutting is performed making a cut on the sheet 1. A preset
period illustrated by the rectangular waveform in FIG. 7 is
defined as a cutter closed period. When the cutter closed
period ends, the shearing cutter moves up. From the value
of the encoder of the servo motor 161, the controller 200
10 checks that the shearing cutter is opened (Step S17).
Depending on the circumstances, the order of Steps S15 and
S12 may be interchanged.
[0035] In the second embodiment, the start of the cutter
operation is earlier than that of the first embodiment so
15 that the dead time from Step S14 at which transport of the
sheet 1 stops to Step S16 at which the shearing cutter is
closed can be reduced as compared to that of the first
embodiment. This makes it possible to reduce the time
required for single-stroke processing, that is, a tact time.
20 [0036] Even when the tact time is reduced in the manner
as described above, it is only required that the controller
200 or the personal computer located outside the control
device 100 generate a constant-rate-feed electronic cam
pattern in which the transport roller speed at the stroke
25 termination 73 becomes constant. Therefore, even when the
tact time that is a machining cycle including cutting,
printing, and the like is reduced in order to increase the
production rate of bags, the coasting amount of the sheet 1
does not vary, but can still be maintained at a constant
30 amount. This makes it possible to produce bags with high
dimensional accuracy.
[0037] The printing unit 5 may be replaced with a
sealing unit that performs sealing operation on the sheet 1
16
during the stop of movement of the sheet 1 that is a
workpiece. In this case, the transport roller 2, the mark
detector 3, the control device 100, and the sealing unit
define the printer. While the transport roller 2 has been
5 described as the transport unit, clip-on transport may be
employed as a transport method, in which the transport unit
picks up and pulls a workpiece.
[0038] The controller 200 or the personal computer that
functions as the cam curve generation device that generates
10 an electronic cam curve according to the first and second
embodiments is implemented by a computer system. FIG. 8 is
a diagram illustrating a hardware configuration of the
computer system that implements the cam curve generation
device according to the first and second embodiments. The
15 computer system in FIG. 8 has a configuration in which a
CPU (Central Processing Unit) 201, a memory 202, a storage
device 203, a display device 204, an input device 205, a
communication interface 206, and the like are connected to
each other through a bus 300. The function of the cam
20 curve generation method to be carried out by the controller
200 or the personal computer is implemented by software,
firmware, or a combination of the software and the firmware.
The software or firmware is written as a program and stored
in the storage device 203. The CPU 201 reads the software
25 or the firmware stored in the storage device 203 into the
memory 202 and executes the read software or firmware to
thereby implement the function of the cam curve generation
device. That is, the computer system includes the storage
device 203 that stores therein programs that eventually
30 execute the steps to carry out the cam curve generation
method according to the first and second embodiments when
the function of the cam curve generation device is
implemented by the CPU 201. Further, it can also be said
17
that these programs cause a computer to execute processes
implemented by the functions of the cam curve generation
device. A volatile storage area such as a RAM (Random
Access Memory) corresponds to the memory 202. A non5
volatile or volatile semiconductor memory such as a ROM
(Read Only Memory) and a flash memory, and a magnetic disk
correspond to the storage device 203. Specific examples of
the display device 204 include a monitor and a display.
Specific examples of the input device 205 include a
10 keyboard, a mouse, and a touch panel. The communication
interface 206 performs communication with external devices.
[0039] The configurations described in the above
embodiments are only examples of the content of the present
invention. The configurations can be combined with other
15 well-known techniques, and part of each of the
configurations can be omitted or modified without departing
from the scope of the present invention.
Reference Signs List
20 [0040] 1 sheet, 2 transport roller, 3 mark detector,
4 mark, 5 printing unit, 6 cutting unit, 10 bag making
machine, 71 electronic cam curve, 72 speed waveform, 73
stroke termination, 100 control device, 121, 151, 161
servo motor, 122, 152, 162 servo amplifier, 201 CPU, 202
25 memory, 203 storage device, 204 display device, 205
input device, 206 communication interface.
18
We Claim:
1. A cam curve generation method for generating an
electronic cam curve showing a relation between a movement
5 distance of a workpiece and a rotational angle of a main
shaft that is a control reference for electronic cam
control, the cam curve generation method comprising
generating the electronic cam curve to allow
repetition of an operation of moving the workpiece and, on
10 a basis of interrupt processing of electronic cam control,
stopping the workpiece, the interrupt processing occurring
during movement of the workpiece, the electronic cam curve
allowing the workpiece to move at a constant speed during a
set period including a point in time when the interrupt
15 processing occurs at each stroke termination of the
repeated operations.
2. A cam curve generation device to generate an
electronic cam curve showing a relation between a movement
20 distance of a workpiece and a rotational angle of a main
shaft that is a control reference for electronic cam
control, wherein
the cam curve generation device generates the
electronic cam curve to allow repetition of an operation of
25 moving the workpiece and, on a basis of interrupt
processing of electronic cam control, stopping the
workpiece, the interrupt processing occurring during
movement of the workpiece, the electronic cam curve
allowing the workpiece to move at a constant speed during a
30 set period including a point in time when the interrupt
processing occurs at each stroke termination of the
repeated operations.
19
3. A control device to control movement of a workpiece by
using an electronic cam curve showing a relation between a
movement distance of the workpiece and a rotational angle
of a main shaft that is a reference, wherein
5 the control device controls movement of the workpiece
so as to repeat an operation of moving the workpiece and,
on a basis of interrupt processing of electronic cam
control, stopping the workpiece, the interrupt processing
occurring during movement of the workpiece, the control
10 device controlling movement of the workpiece so as to move
the workpiece at a constant speed during a set period
including a point in time when the interrupt processing
occurs at each stroke termination of the repeated
operations.
15
4. A transport device comprising:
the control device according to claim 3;
a transport unit to be driven and controlled by the
control device on a basis of the electronic cam curve for
20 transporting the workpiece; and
a detection unit to detect a mark marked on the
workpiece and then output a detection result to the control
device, wherein
the control device causes the interrupt processing to
25 occur on a basis of the detection result.
5. A printer comprising:
the transport device according to claim 4; and
a printing unit to be driven and controlled by the
30 control device on a basis of the electronic cam curve for
making a print on the workpiece during a stop of the
workpiece.
20
6. A cutter comprising:
the transport device according to claim 4; and
a cutting unit to be driven and controlled by the
control device on a basis of the electronic cam curve for
5 starting operation before a stop of the workpiece and
cutting the workpiece during a stop of movement of the
workpiece.
7. A bag making machine comprising the cutter according
10 to claim 6, wherein
the workpiece is in a form of plural bag-like sheets
connected with one another through connection portions
thereof, and
the cutting unit cuts the workpiece at the connection
15 portions to produce plural bags.