U.S. patent application number 10/175117 was filed with the patent office on 2003-03-13 for bagging machine with integrated printer.
This patent application is currently assigned to Automated Packaging Systems, Inc.. Invention is credited to Burke, Jeffrey, Cronauer, William M., Ferrante, Robert L., Lerner, Bernard.
Application Number | 20030046902 10/175117 |
Document ID | / |
Family ID | 26870879 |
Filed Date | 2003-03-13 |
United States Patent
Application |
20030046902 |
Kind Code |
A1 |
Cronauer, William M. ; et
al. |
March 13, 2003 |
Bagging machine with integrated printer
Abstract
A method for printing indicia on bags interconnected in a
continuous web. A bagging machine has a printer and a plurality of
tensioning rollers, at least one of which is driven by a roller
motor. The web is moved from an initial bagging machine station
through a print station and to a load station in which goods are
placed in the bags. A perforation sensor featuring a spring biased
hemispherical tip indicates to a bagging machine controller that a
perforation is present. First roller motor control signals are
received from a printer controller comprising a frequency modulated
first motor speed signal and a first motor enable signal. The first
roller motor control signals are transmitted to the roller motor to
cause it to drive the roller to move bags through the print
station. Second roller motor control signals are received from the
bagging machine controller comprising a frequency modulated second
motor speed signal and a second motor enable signal and these
signals are transmitted to the roller motor to cause the motor to
drive the roller to move bags to the final station. This cycle is
repeated such that at any given time either first roller motor
speed signal or the second roller motor speed signal, but not both
simultaneously, are being transmitted to the roller motor. This is
accomplished by providing a control signal to a multiplexer that
provides a selected speed signal to the roller motor based on the
control signal. The speed signals are generated by selecting
resistor components that are coupled to a voltage controlled
oscillator to provide a frequency modulated motor speed signal. A
perforation sensor featuring a spring biased hemispherical tip
indicates to the bagging machine controller that a perforation is
present.
Inventors: |
Cronauer, William M.;
(Tallmadge, OH) ; Lerner, Bernard; (Aurora,
OH) ; Burke, Jeffrey; (Aurora, OH) ; Ferrante,
Robert L.; (Ravenna, OH) |
Correspondence
Address: |
WATTS, HOFFMANN, FISHER & HEINKE CO., L.P.A.
1100 Superior Ave., Ste. 1750
Cleveland
OH
44114
US
|
Assignee: |
Automated Packaging Systems,
Inc.
|
Family ID: |
26870879 |
Appl. No.: |
10/175117 |
Filed: |
June 19, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60318240 |
Sep 7, 2001 |
|
|
|
Current U.S.
Class: |
53/411 ;
53/131.5; 53/64 |
Current CPC
Class: |
B65B 43/123 20130101;
B65B 57/08 20130101; B65B 61/025 20130101 |
Class at
Publication: |
53/411 ;
53/131.5; 53/64 |
International
Class: |
B65B 057/02; B65B
061/02 |
Claims
we claim
1) A method for printing indicia on bags interconnected in a
continuous web and being processed by a bagging machine having a
printer and a plurality of tensioning rollers that move the web
from an initial bagging machine station through a print station and
to a final station, wherein at least one of the rollers is driven
by a roller motor, the method comprising the steps of: a) receiving
first roller motor control signals from a printer controller; b)
transmitting the first roller motor control signals to the roller
motor to cause the motor to drive the roller to move bags through
the print station; c) receiving second roller motor control signals
from a bagging machine controller; d) transmitting the second
roller motor control signals to the roller motor to cause the motor
to drive the roller to move bags to the final station; and e)
repeating steps a-d such that at any given time either first roller
motor control signals or second roller control signals, but not
both simultaneously, are being transmitted to the roller motor.
2. The method of claim 1 wherein the final station is a load
station wherein bags are filled with goods.
3. The method of claim 1 wherein the bagging machine controller
transmits third motor control signals to the roller motor after the
bags reach the final station to cause the roller to move bags in a
reverse direction away from the final station a predetermined
distance to reposition a given bag for printing.
4. The method of claim 1 wherein the first roller motor control
signals comprise a motor enable signal.
5. The method of claim 1 wherein the first roller motor control
signals comprise a motor speed signal.
6. The method of claim 1 wherein the second roller motor control
signals comprise a motor enable signal.
7. The method of claim 1 wherein the second roller motor control
signals comprise a motor speed signal.
8. The method of claim 1 wherein the first roller motor control
signals comprise a motor speed signal and the second roller motor
control signals comprise a motor speed signal and wherein the first
motor speed signal corresponds to a slower roller speed than the
second motor speed signal.
9. The method of claim 1 wherein the first and second roller motor
control signals comprise frequency modulated signals wherein the
frequency of the signal corresponds to a desired motor speed.
10. The method of claim 1 wherein the first roller motor control
signal comprises a signal that corresponds to a rate of
acceleration for the motor.
11. The method of claim 1 wherein the second roller motor control
signal comprises a signal that corresponds to a rate of
acceleration for the motor.
12. The method of claim 1 wherein step e is performed by forming a
logical OR combination of motor enable signals from the printer
controller and the bagging machine controller.
13. The method of claim 1 wherein step e is performed by providing
a control signal to a multiplexer that provides a selected speed
signal to the roller motor based on the control signal.
14. The method of claim 1 wherein one of the roller motor control
signals comprises a motor speed signal and the motor speed signal
is provided by selecting resistor components that are coupled to a
voltage controlled oscillator to provide a frequency modulated
motor speed signal.
15. A method for printing indicia on bags interconnected in a
continuous web and being processed by a bagging machine having a
printer and a plurality of tensioning rollers that move the web
from an initial bagging machine station through a print station and
to a load station in which goods are placed in the bags, wherein at
least one of the rollers is driven by a roller motor, the method
comprising the steps of: a) receiving first roller motor control
signals from a printer controller comprising a frequency modulated
first motor speed signal and a first motor enable signal; b)
transmitting the first roller motor control signals to the roller
motor to cause the motor to drive the roller to move bags through
the print station; c) receiving second roller motor control signals
from a bagging machine controller comprising a frequency modulated
second motor speed signal and a second motor enable signal; d)
transmitting the second roller motor control signals to the roller
motor to cause the motor to drive the roller to move bags to the
final station; and e) repeating steps a-d such that at any given
time either first roller motor speed signal or the second roller
motor speed signal, but not both simultaneously, are being
transmitted to the roller motor by providing a control signal to a
multiplexer that provides a selected speed signal to the roller
motor based on the control signal and wherein the speed signals are
generated by selecting resistor components that are coupled to a
voltage controlled oscillator to provide a frequency modulated
motor speed signal.
16. The method of claim 15 wherein the first motor speed signal
corresponds to a slower roller speed than the second motor speed
signal.
17. The method of claim 15 wherein at least one of the roller motor
control signals comprises a signal that corresponds to a rate of
acceleration for the motor.
18. The method of claim 15 wherein step e is performed by forming a
logical OR combination of motor enable signals from the printer
controller and the bagging machine controller.
19. An apparatus for printing indicia on bags perforatedly
interconnected in a continuous web comprising: a) a bagging machine
comprising an initial station for mounting a stock quantity of
empty bags, a plurality of tensioning rollers for moving the web of
bags from the initial station, through a print station, to a final
station; b) a motor connected to at least one of the tensioning
rollers for driving the roller to move the web of bags; c) a
printer controller for providing first motor control signals for
controlling the motor; d) a bagging machine controller for
providing second motor control signals for controlling the motor;
e) a sequencer for receiving the first and second motor control
signals and passing one, but not both, of the signals to the motor
according to a control algorithm.
20. The apparatus of claim 19 wherein the sequencer comprises a
multiplexer that provides either the first or second motor control
signal to the roller motor from either the printer controller or
the bagging machine controller according to the control
algorithm.
21. The apparatus of claim 19 wherein the sequencer comprises means
for forming a logical OR combination of the first and second motor
control signals.
22. The apparatus of claim 19 comprising means for selecting
resistor components that are coupled to a voltage controlled
oscillator to provide a frequency modulated motor speed signal.
23. The apparatus of claim 19 comprising a perforation detector for
sensing perforations between bags in the web and transmitting a
perforation signal that indicates a perforation is present to the
bagging machine controller.
24. The apparatus of claim 23 wherein the bagging machine
controller receives the perforation signal and uses the signal to
monitor the position of the web of bags.
25. The apparatus of claim 23 wherein the perforation detector
comprises: a generally hemispherical sensing tip; a biasing spring
engaging the sensing tip and urging it toward a conducting plate; a
voltage source in electrical communication with the sensing tip for
energizing the sensing tip to cause a potential difference between
the sensing tip and the conducting plate; and wherein the web of
bags is fed between the sensing tip and the conducting plate and
wherein perforations between the bags permit an arc to pass between
the sensing tip and conducting plate to register a perforation
signature and wherein in the absence of perforations, arcing is
prevented.
26. An perforation sensing apparatus for sensing perforations
between bags in an interconnected web and providing a signal
indicative that a perforation is present comprising: a generally
hemispherical sensing tip; a biasing spring engaging the sensing
tip and urging it toward a conducting plate; a voltage source in
electrical communication with the sensing tip for energizing the
sensing tip to cause a potential difference between the sensing tip
and the conducting plate; and wherein the web of bags is fed
between the sensing tip and the conducting plate and wherein
perforations between the bags permit an arc to pass between the
sensing tip and conducting plate to register a perforation
signature and wherein in the absence of perforations, arcing is
prevented.
Description
FIELD OF THE INVENTION
[0001] The present invention concerning a bagging machine having an
integrated printer for printing indicia onto a bag just prior to
loading the bag with one or more articles. The invention is
particularly well suited for packaging quantities of
pharmaceuticals to fill individual orders and the process of
filling such orders as well as other mail order applications.
BACKGROUND ART
[0002] Machines that use webs of preopened bags to form packages
are now well known. Such webs of bags are disclosed and claimed in
the U.S. Pat. No. 3,254,828 entitled Flexible Container Strips (the
Autobag Patent). A machine that is currently in wide usage
commercially for forming packages from chains of preopened bags is
described in U.S. Pat. No. 5,394,676 (the Excel Patent). Machines
made in accordance with the teaching of the Excel Patent often are
supplied parts to be packaged by modular systems of counters and/or
weighers and conveyors in order that packages can be formed
automatically and at relatively high speeds.
[0003] The Excel machines are often equipped with printers such as
that described and claimed in U.S. Pat. No. 5,371,521 issued Dec.
6, 1994 to Rick S. Wehrmann (the Teeter Totter Patent). The Teeter
Totter Patent is directed to a mechanism which tensions the film
and feeds it past a print head in a section of a web of bags that
is isolated from a section which feeds bags to a load station such
that the two sections are independently tensioned. The Excel Patent
teaches a dancer mechanism which independently tensions a web
section upstream from the printer section so that there are three
isolated individually tensioned sections along the feed path of an
Excel machine equipped with a printer. While this system is
efficient for printing multiple bags with the same information, the
presence of a number of bags between the printer and bagging
machine complicates the process of changing over the printed
indicia and may result in a number of scrap bags if the bagging
machine jams.
[0004] Relatively large "mail order" organizations with systems for
filling pharmaceutical orders for home delivery require different
printed information on each bag. To package their orders, these
mail order organizations typically utilize so-called wicketed bags
for packaging individual orders for shipment. Pressure sensitive
labels are used to identify the contents of the given bag and to
provide an address for shipment of the bag to the customer. The
wicketed bag approach is slow and expensive. It is especially
expensive in that only registered pharmacists can fill individual
bags with pharmaceutical orders.
[0005] A machine that is a modified version of the Excel machine is
currently being offered for sale. This modified machine has what
features a "ditch" to receive and accumulate bags after they have
been printed but before they are fed to a load station. This
accumulation of bags results in printing errors and wrinkling of
bags resulting in finished packages that are not as attractive as
they should be. Such wrinkling can make bar codes printed on the
bags unreadable.
[0006] Accordingly it would be desirable to provide a machine which
uses a web of preopened bags for packaging individual orders and
which prints identifying information on a bag immediately before it
is loaded and sealed.
SUMMARY OF THE INVENTION
[0007] A bagging machine having a drive roller for engaging a
surface-of an endmost bag in a chain of interconnected bags and
moving the endmost bag to a bagging station. A supply of
interconnected bags supplies bags to the bagging station. A motor
rotates the drive roller in a controlled fashion to route the
interconnected bags along a travel path to the bagging station from
the supply. A printer positioned with respect to the endmost bag
can apply indicia unique to the endmost bag prior to filling the
endmost bag with one or more articles at the bagging station. A
controller applies energization signals to the motor for
controlling movement of the endmost bag. The controller has an
interface with both the motor and the printer to coordinate
movement of the endmost bag with printing of indicia by the
printer. By switching control of the motor between the printer and
bagging machine, it is possible to print a bag just prior to its
being filled thereby streamlining the bagging process.
[0008] According to an embodiment of the present invention, indicia
is printed on bags interconnected in a continuous web and being
processed by a bagging machine having a printer and a plurality of
tensioning rollers that move the web from an initial bagging
machine station through a print station and to a final station,
such as a load station. At least one of the rollers is driven by a
roller motor that is controlled according to the present invention.
A perforation sensor featuring a spring biased hemispherical tip
indicates to a bagging machine controller that a perforation is
present. First roller motor control signals are received from a
printer controller and transmitted to the roller motor to cause the
motor to drive the roller to move bags through the print station.
Second roller motor control signals are received from the bagging
machine controller and transmitted to the roller motor to cause the
motor to drive the roller to move bags to the final station. These
steps are repeated such that at any given time either first roller
motor control signals or second roller control signals, but not
both simultaneously, are being transmitted to the roller motor. In
an exemplary embodiment, the bagging machine controller transmits
third motor control signals to the roller motor after the bags
reach the final station to cause the roller to move bags in a
reverse direction away from the final station a predetermined
distance to reposition a given bag for printing.
[0009] According to a feature of the present invention, the motor
control signals include motor speed, acceleration, enable signals.
The motor speed signals received from the printer may correspond to
a slower roller speed to accommodate printer speed while the motor
speed signals form the bagging machine may correspond to higher
speeds to speed up overall operation. According to a feature, the
first and second roller motor control signals are frequency
modulated signals wherein the frequency of the signal corresponds
to a desired motor speed.
[0010] The synchronization of signals from the bagging machine and
printer is accomplished by forming a logical OR combination of
motor enable signals from the printer controller and the bagging
machine controller and by providing a control signal to a
multiplexer that provides a selected speed signal to the roller
motor based on the control signal. According to a feature the motor
speed signal is provided by selecting resistor components that are
coupled to a voltage controlled oscillator to provide a frequency
modulated motor speed signal.
[0011] These and other objects, advantages, and features of the
invention will be better understood from the accompanying detailed
description of a preferred embodiment of the invention when
reviewed in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a perspective view of a bagging machine
constructed in accordance with an exemplary embodiment of the
invention;
[0013] FIGS. 2A-2C are block diagrams illustrating control
components of the bagging machine of FIG. 1;
[0014] FIG. 3 is a side elevation view of a printer and feed rolls
that move a bag into a loading station;
[0015] FIG. 4 is an enlarged elevation view of the depiction of
FIG. 3 showing a print head and perforation detecting device;
[0016] FIGS. 5A-5C are electrical schematics of a portion of a
bagging machine controller for coordinating movement of a chain of
bags with printing by the printer on those bags;
[0017] FIG. 6 is an exploded view of the perforation detecting
device shown in FIG. 4; and
[0018] FIG. 7 is a flow diagram of a method employed by the bagging
machine of FIG. 1.
EXEMPLARY EMBODIMENT OF THE PRESENT INVENTION
[0019] FIG. 1 illustrates a bagging machine 10 that includes a user
interface 12 that allows a user or operator to adjust various
bagging parameters such as seal temperature, bag length, time
between cycles for an automated loading system and the like. The
user interface is supported by pedestal support 14 which in turn is
supported by a base 16 having generally horizontal support members
16a, 16b, 16c that include rollers for repositioning the bagging
machine 10.
[0020] The bagging machine defines a bagging station indicated
generally as 20 which is a position where articles can be dropped
into the end most bag of a chain of interconnected bags. Just prior
to the bagging station the machine 10 includes a pair of feed
rollers 22, 24 (FIGS. 3 and 4) for driving an end most bag (not
shown) of the chain of interconnected bags from a supply (not
shown). The supply contains a coiled sequence of interconnected
plastic bags separated from each other by perforation lines that
extend across the width of the bags and allow easy separation of
the bags once an endmost bag has been filled. The supply is mounted
for rotation to a spindle 32 to dispense the outermost layer of
bags from the supply.
[0021] During machine set up, an operator unwinds the chain of bags
from the supply and routes the bags through a dancer roll assembly
34 underneath a printer 40 and into a nip 42 formed by the two
drive rollers 22, 24 (FIGS. 3 and 4). The dancer roll assembly 34
similar to the dancer roll assembly shown in U.S. Pat. No.
5,341,625. A separate drive roll pulls the chain of bags from the
supply during operation of the bagging machine and the dancer roll
assembly 34 maintains a tension between the supply and the dancer
assembly while allowing the nip of the drive rollers 22, 24 to
intermittently pull bags through a region of printing to the
bagging station. An orientation of the dancer roll assembly
controls intermittent operation of this separate drive roll. After
passing through the dancer assembly 34, the bags move upward away
from the dancer roll along a bag path of travel past the printer 40
where indicia is applied to each bag under the control of an
electronic circuit to be described in greater detail below.
[0022] At the bagging station, the bag is held open by a stream of
air (not shown) so that the articles can be either manually dropped
through a chute into a bag or brought to the bagging station by a
conveyor (not shown) which drops the articles into a chute and into
an opened end most bag that is still attached to the serial chain
of interconnected bags. The filled bag is then sealed and separated
from the chain for removal from the bagging station to a separate
location.
[0023] One feature of the invention is an ability to print
information onto the bag immediately before the bag is moved
forward to the bagging station where articles are inserted into the
bag. One application to which the bagging machine built in
accordance with the invention has special utility is for bagging
prescription drugs. Information specific to the end user such as an
address and instructions for taking the drugs as well as the
contents of the bag are printed on the bag immediately before the
prescription drug is loaded into the bag. Practice of the present
invention allows information to be printed onto the bag just prior
to movement of the bag to a position for loading.
[0024] FIGS. 3 and 4 are side elevation views of the printer 40
that is located in close proximity to the bagging station to
facilitate printing on bags immediately prior to their being
filled. As is shown in FIG. 3, the printer includes a reel-to-reel
type system for delivering print ribbon to a print station above
the bag in a controlled manner. A supply roll 50 rotates in a
clockwise direction to feed a printer tape (not shown) over a
pulley 54 to the print station 56 where indicia is applied to a
generally flat outer surface of the bag that is about to be filled.
The spent print tape is reeved around a second pulley 60 at the
location of the print station 56 and returned to a pick up roll 62,
which rotates, in a counterclockwise direction and is located to
the right of the supply roll 50 in FIG. 2.
[0025] A print head 70 is shown in greater detail in FIG. 3. The
print head 70 includes a heating element. The heating element
selectively applies heat to the tape and through a known thermal
transfer process applies the indicia to the bag from the printing
tape. Selective energization and thus heating of the print head
element is controlled by a controller within the printer 40. The
print head controller encodes the bag with information supplied to
the printer from a separate data source. In the disclosed
embodiment of the invention, the separate data source is a database
stored on a separate computer, which is downloaded to the printer
40 by means of a serial communications port coupled between the
separate computer and the printer 40. This serially transmitted
information is received by a controller within the printer, which
then selectively energizes the thermal print head in a manner to
encode the information onto a bag.
[0026] FIG. 3 also illustrates the feed rollers 22, 24 that defines
a nip for moving the end most bag from the region of the printer
and print head to the bagging station. As seen in the enlarged view
of FIG. 4, there are two rollers, which define a nip 42 through
which the bag is routed during setup. The bottom most roller 22 is
a driver roll so that controller rotation of this roller moves the
bag through the nip to the bagging station. The roller 22 is
coupled by means of a transmission to a stepper motor (shown
schematically as 140 in FIG. 2A) having an output shaft whose speed
of rotation is controlled by a bagging machine controller (shown
schematically as 130 in FIG. 2A). The top most roller 24 is spring
loaded against the driver roller 22 by a spring 19 and is driven by
the frictional engagement therebetween.
[0027] It is a feature of the invention that this driver roller 22
can be reverse activated to retract the bag through the nip after
the preceding bag has been loaded, sealed and separated thereby
allowing printing to occur over most of the bag's surface. This
backwards movement of the bag is accomplished in part by use of a
new perforation sensor 100 (shown in detail in FIG. 6) for sensing
bag location. A print roll 80 in immediate proximity to the print
head is driven by a belt 81 connected to the driver roll 22 and
supports the bag in the region the print head applies indicia to
the bag. During reverse actuation of the driver roll 22, as will be
discussed in greater detail later, the dancer roll assembly pulls
the chain of bags backward by the weight of the dancer roll to
maintain a tension in a region of the printer.
[0028] FIG. 6 is an exploded perspective view of a perforation
sensor 100 which is shown in phantom in the side view of FIG. 3.
The sensor 100 includes a metal semi-hemispherical tip 102 which
engages the bag as it moves past the sensor 100. This tip is biased
against the bag by a compressed spring 104 trapped within a
cylindrical sleeve 110, which in turn is mounted to a flange 112
electrically coupled to high voltage source of power. The
energization from the source occurs through a tab, which is spaced
from the cylindrical sleeve 110. When supported within the sleeve,
the tip 102 contacts the bag and as the bag moves, at periodic
intervals, a transverse line of perforations passes over the sensor
100. When this occurs, there is a region of low dielectric constant
i.e. the air between the sensor and a metal backing (not shown)
against which the sensor is biased. This low dielectric results in
a spark occurring, which is fed back through the high voltage input
to the sensor to a sensing circuit. This causes a reduction in the
voltage due to the periodic shorting of the perforation sensor 100,
which in turn indicates to the drive control that the bag has
reached a certain location with respect to the print head and the
bagging station. During intervals in which the bag (without
perforations) is between the sensor the metallic backing, the
die-electric constant is higher and inhibits the sparking that
occurs when the perforations are sensed.
[0029] Bagging Machine Controller
[0030] FIGS. 2A through 2C are block diagrams of the control system
130 for the bagging machine. The stepper motor 140 that drives the
driver roll 22 (FIG. 3) is controlled by signals provided to a
control adapter board 133b by a sequencer 131. The sequencer
switches control of the stepper motor 140 between controls
associated with the bagging machine 132 and controls associated
with the printer 133. In doing so, the sequencer 131 causes the
motor to be controlled by the device utilizing the motor at any
given time. For example, during the printing interval of the cycle,
the printer controls 133 cause the motor to rotate the driver roll
22 at a relatively slow speed. The printer controls 133 may also
rotate the drive roll at an intermediate indexing speed to
precisely position the bag for the next printing interval. After
printing, the bagging machine controls cause the motor to rotate
the driver roll at a relatively high speed to place the bag in
loading position and to move the bag backward to tear the bag away
from the web and, if necessary, move the web further back to
position the next bag in its print position.
[0031] The sequencer 131 contains a microcontroller (U1 in FIG. 5A)
designated PIC16C74B -20/P (supplied by Microchip located in
Arizona). An assembly language program is resident in memory on the
microcontroller for controlling the stepper motor 140 based on
signals from a bagger controller 132 and a printer controller 133a.
The stepper motor 140 receives an enable signal, S_MENA, and a
frequency modulated signal, S_MSTEP, that controls the speed and
rate of acceleration of the stepper motor from a motor control
board 133b that is resident on the printer controller. S_MENA is
provided by an OR combination performed by a sequencer enable
module 138. The motor enable signal from the bagging machine
(STEP_INH) is combined with a motor enable signal from the printer
(MENA) such that if either device is providing an enable signal,
the motor 140 is enabled. S_MSTEP is derived from the sequencer and
more specifically by a selection of resistor components coupled to
a voltage controlled oscillator U5 shown in FIG. 5B whose output is
ESTEP_CLK. The sequencer 131 controls a multiplexer 138 that
provides the signal S_MSTEP by switching between a signal provided
by the bagging machine (ESTEP_CLK) and a signal provided by the
printer (MSTEP).
[0032] Referring to FIGS. 2A-2C and also to FIG. 7 wherein a flow
diagram of a bagging method 150 employed by the sequencer to
control the operation of the bagging machine is depicted. The
sequencer 131 is cued to begin a print portion of a bagging machine
cycle by a start of cycle, SOC, signal from the bagger controller
132 in step 155. The sequencer signals the printer to start
printing by setting an appropriate bit on the /FULL line in step
160. In step 165 the printer controller 133 then passes MSTEP and
MENA, step motor and motor enable signals, respectively, back to
the sequencer 131. The MSTEP signal is input to the multiplexer 138
that is used to generate the S_MSTEP signal sent to the motor
control board 133b to control the speed and rate of acceleration of
the stepper motor 140 in step 170. When the printer has finished
printing, it sets the MENA bit to "inactive" to indicate that it is
finished in step 175. The sequencer 130 then passes the ESTEP_CLK
signal from the bagger controller 132 to the multiplexer 138 in
step 180 to generate the S_MSTEP signal sent to the motor control
board 133b in step 185. The bagger controller 132 signals it has
positioned the printed bag in load position by setting the STEP_INH
bit to "inactive" in step 190. After step 190, the sequencer waits
for the SOC from the bagger and meanwhile the bagger controller
causes the stepper motor 140 to reverse the web of bags to tear the
printed bag off and position the next bag for printing. The
sequencer continues cycling stepper motor control between the
printer and bagger controllers in this manner.
[0033] FIGS. 5A-5C are a detailed schematic of the circuitry, which
is mounted to a board contained within the existing Excel bagger
system. This circuit board implements functionality previously
implemented on a printer circuit board so that there has been a
modification to the control to the printer to accommodate different
operation by the existing bagger. FIG. 5A depicts a programmable
controller U1 that contains a memory having less than 256 bytes of
control program for implementing the control function of the
printer and a second programmable logic array U4, that interfaces
with the microprocessor that controls printing. Several relevant
signals referred to in FIGS. 2 and 7 are labeled in FIG. 5A for
convenience. The source code (written in assembly language) for the
programmable controller shown in FIG. 5A sits in an idle loop
waiting for receipt of the start of cycle signal. Receipt of this
signal causes the controller to perform one of its control
functions depending upon the status of various bytes that are set
and as outlined in the flow diagram of FIG. 7.
[0034] FIG. 5B illustrates schematically a phased lock loop circuit
and specifically the phase lock loop circuit includes a voltage
control oscillator U3 that is used during ramp up of the motor ramp
down of the motor as the bag is driven from its position under the
printer head to the bagging station. This occurs in a controlled
fashion by means of the programmable controller U1 that outputs a
signal correlating to the desired speed for the motor as ESTEP_CLK.
U3 also feeds the ESTEP_CLK signal back to logic array U4. FIG. 5C
is an interface diagram that includes an input, MENA, from the
precision printer central processing unit 133a indicating a motor
enable signal, S_MENA, is appropriate since the print function has
been completed.
[0035] While a detailed description of an exemplary embodiment of
the present invention has been described with a degree of
particularity, it is the intent that the invention include all
modifications and alterations from the disclosed design falling
within the spirit or scope of the appended claims.
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