JUKI 6100 User manual

CONTENTS
^3 EMER/\ L•*•••1
1Bssic SpGcif icstions ,1
2. Main Component Units 1
2.1 Print unit 1
212 ntrolunit •••*•*••*•* 1
2.3 Cover unit 1
3. Block Diagrams 2
3.1 Block diagram of all component units 2
3.2 Block diagram of control boards 2
4. Operation of Print Unit Mechanisms 3
4.1 Carriage feed mechanism 3
4.2 Character selection mechansism 6
4.3 Hammer mechanism 6
4.4 Ribbon feed mechanism 7
4.5 Form feed mechanism 7
5. Removal and Replacement 8
5.1 Maintenance tools 8
5.2 Disassembly and assembly 9
6. Adjustment 31
6.1 Carriage unit and linear motor unit adjustment 31
6.2 Ribbon mechanism adjustment 42
6.3 Platen drive mechanism adjustment 46
6.4 Paper bail adjustment 47
7. Theory of Operation 48
7.1 Power supply 48
7.2 MCU and SCU operations 54
7.3 Daisy motor and linear motor home position sensor circuit 61
7.4 Control panel 62
8. Lubrication 65
8.1 Lubricating the carriage unit 66
8.2 Lubricating the frame unit 67
8.3 Lubricating the parts 68
9. Configuration 70
10. Troubleshooting 71
10.1 General desciption 71
10.2 Troubleshooting 71

GENERAL
This Technical Manual describes the maintenance, troubleshooting, and operating
principle of the daisy wheel printer.
1. Basic Specifications
Print speed
Print system
Print wheel
Character spacing
Line spacing
Form feed
Max. form width
Copies
Ribbon
Interface
Environmental requirements
Weight
18characters/second (Max.)
Daisy wheel
1OO-characters/wheel
110 characters under 10 pitch.
132 characters under 12 pitch.
165 characters under 15 pitch.
82 to 220 characters under proportional spacing mode.
1/48 inch (1 /96 inch possible by ESC sequence)
Friction feed
13 inches (printing line 1 1 inches)
Original copy +3copies
IBM 82 compatible multi strike or single strike ribbon
(selectric II ribbon)
Centronics parallel interface
RS232C Serial Interface (Option)
Temperature 41°F ~95°F(5 ~35°C)
Humidity 30% ~85% (no dew condensation)
About 27.5 lbs. (about 12.5 kg)
2. Main Component Units
This printer consists of the following three major units.
2.1 Print unit
The print unit is comprised of the frame assembly, carriage and linear motor unit
and the form feed mechanism. Occupying the largest part of the print unit, the
carriage performs lateral feed, character selection, printing and ribbon feed. Use
of aliner motor makes the carriage simple in design for easy maintenance.
2.2 Control unit
This unit provides all the controls for the printer and consists of apower supply
and two CPU boards. One of the CPU circuit boards serves as the slave CPU
circuit board for controlling the print unit mechanisms, and the other is the master
CPU circuit baord for controlling the slave CPU circuit board and for the commu-
nication with the host CPU.
2.3 Cover unit
The cover unit consists of abottom cover, center cover, top cover, and acoustic
cover. Except for two screws, snap-latches are used for connection between the
covers.

3. Block Diagrams
3.1 Block diagram of all component units
Interface >'
<
Operation
panel
<
Power supply
Control
board
Carriage
PF motor
Status SW
Fig. 3.1
3.2 Block diagram of control boards
Serial interface
connector
77
V
1
Buffer Buffer
8251
UART
1
Serial interface
board (option)
Parallel interface
connector
A
Operation panel
connector
7>
Buffer
ABuffer
RAM 2k byte
(MAY 8k byte)
ROM
8k byte
JL
y.
256 byte RAM
8155
Timer I/O port
0"
8051 Master CPU
AMaster CPU board
V
8051 Slave CPU
7%
iz
Driver circuit
Carriage, PF Motor,
status SW connector
Slave CPU board
Fig. 3.2
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As previously described in Section 2"Main Component Units", all communications to
the host CPU and all printing functions are performed by the control unit. Two sepa-
rate circuit boards, the Master CPU and the Slave CPU, comprise the Control Unit. The
standard printer comes with aCentronics compatible Parallel Interface. An optional
serial interface board is also available which attaches directly to the master CPU board.
Installation of the serial interface over-rides the parallel interface, in effect, making the
two interfaces mutually exclusive.
oMaster CPU
Data from the host CPU received via parallel interface is latched at the I/O port of
the 8155. The 8051 master CPU retrieves this data and stores it into RAM. The
master CPU then reads data from RAM, performs computations and transfers the
data necessary for printing to the slave CPU. All data retrieved from RAM is checked
for embeded escape sequences or special control codes.
oSlave CPU
In response to the commands received from the master CPU, the slave CPU will
energize the appropriate driver circuits to perform the printing function. Among the
components under control of the slave CPU are the linear motor, selection motor,
ribbon motor, clutch magnet and the line feed motor. The 805 1on the slave CPU
board has two timers which aid the CPU in controlling two of the control compo-
nents in an overlap mode. An example would be during the print operation when
after acharacter has been printed, the CPU operates the linear motor to move to the
next print position while it is operating the selection motor to align the next charac-
ter to print. The operation of all the necessary components for printing being
controlled by asignle slave CPU is seen as one of this printers strongest features.
4. Operation of Print Unit Mechanisms
The print unit mechanism may be divided into the following five mechanisms:
(1) Carriage feed mechanism
(2) Character selection
(3) Hammer mechanism
(4) Ribbon feed mechanism
(5) Form feed mechanism
4.1 Carriage feed mechanism
The carriage feed mechanism is directly driven by alinear stepping motor. It is
controlled by the CPU according to the driving timing which has been stored
beforehand, and is driven by constant-current based on frequency modulation.
Further, this carriage feed mechanism is designed to reduce the driving current
while not in use, thereby avoiding waste of power. The resolution of the lateral
feed is 1/120 inch.
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The positional detection is done at the leftmost point. This positional detection
is done to detect the home position, and no positional detection will be done
during printing. In other words, since open-loop control is used, no out-of-position
prints caused by erroneous feed made by external force during printing will be
corrected. In the following cases, however, the printer will move its carriage to the
left end to detect the home position and then indicate the error or correct the
position:
*The home position is detected using the form feed code. If, at this time, any
feed error caused by an external force already exists, an error indication will be
given.
*With the printer stopped by operating the pause switch, if you inadvertently
move the carriage while doing ribbon replacement or the like, operate the
check switch to restart the printer. Then the printer will detect the home
position to correct the position for normal printing.
The carriage will perform high-speed skipping for higher effective printing speed.
The skipping comes in long skipping and short skipping, each having different
skipping speed. The linear motor uses apermanent magnet and is driven by the
interaction with the driving current.
Permanent magnet
Rail
Fig. 4.1
When currents are allowed to flow through the coils as shown in Fig. 4.1, the
magnetic fluxes produced by the coils and those produced by the permanent
magnet will flow through the poles of the coil 01 and coil 03. In the coils 02 and
04, the direction of the fluxes produced by the coils is opposite from that of the
fluxes produced by the permanent magnet and therefore the both fluxes will
cancel each other. As aresult, the magnetic poles of the coils 01 and 03 are
attracted to the poles of the rail, causing the motor to stop as shown in Fig. 4.1
.

Fig. 4.2
When currents are allowed to flow through only the coil 03 as shown in Fig. 4.2,
the magnetic fluxes produced by the coil and the permanent magnet will flow
through the poles of the coil 03, causing the motor to move the right and then
stop in the position indicated in Fig. 4.2.
Fig. 4.3
Further, when currents are let flow through the coils 01 and 02 in the opposite
direction from the above, the magnetic fluxes produced by the coils and those
produced by the permanent magnet will cancel each other at the poles of the coil
01 because of their opposite direction. The magnetic fluxes generated by the coils
and the permanent magnet will go through the poles of the coil 02. Consequently,
the poles of the coils 02 and 03 will be attracted to the poles of the rail, and the
motor will further move to the right before it stops at the point indicated in Fig.
4.3.
Thus, the motor is moved by successively changing the direction of the currents
flowing through the coils.
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4.2 Character selection mechanism
The character selection mechanism is directly driven by astepping motor. It is
controlled by the CPU according to the driving timing which has been stored
beforehand, and is driven by constant-current. Large currents flow through the
mechanism during acceleration but the currents grow smaller as the speed in-
creases. Further, it is designed to reduce the driving current wile not in use in
order to avoid waste of power. The rotational resolution is 3.6°, i.e., there are 100
stop positions per revolution, which correspond to the number of printable chara-
cters on the daisy wheel. The daisy wheel is to be dropped in for setting. To
perform the initial setting, move the carriage to the left end and run the motor to
position the daisy wheel.
The daisy wheel is positioned by the following mechanism.
Arm
Fig. 4.4
When the carriage is moved to the left end, the arm on the frame depresses the
case lever. When the daisy motor runs and the pin of the case lever enters the hole
in the daisy wheel, the daisy wheel stops rotating. As the motor further runs until
the positioning pin enters the positioning hole in the daisy wheel, the rotation of
the daisy wheel will be synchronized with the motor running.
4.3 Hammer mechanism
The Hammer mechanism consists of along-stroke plunger magnet. It is driven by
aconstant-current chopper circuit which is controlled by the slave CPU. Impact
pressure is determined by the length of time that the driver circuit is energized
and can be varied according to the size of the character to be printed.
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4.4 Ribbon feed mechanism
Awide ribbon which can be vertically shifted in three stages is used. Either a
single-strike ribbon or multi-strike ribbon is used. In the multi-strike ribbon, the
same part is hammered afew times while in the single-strike ribbon the same part
is struck only once.
The drive gear ratio, which determines the amount of ribbon movement, is auto-
matically set according to the type of ribbon cartridge being installed.
1, Single-strike ribbon 2. Multi-strike ribbon
The lift and fall, and winding of the ribbon are done by the dc motor, spring
clutches and clutch magnet through the cams. The spring clutch is used for the
ribbon lift cam and ribbon down cam. When the ribbon motor runs to put the
clutch magnet into operation, aspring clutch works to cause the ribbon lift cam
to turn 1/3. At this time, the ribbon lift cam makes the ribbon move up and down,
and the pawl of the ribbon lift cam kicks the ratchet arm to feed the ribbon.
As the motor runs in the operate the ribbon down cam, making the ribbon go
down to the lowest position. The ribbon down cam is activated at the end of a
print operation to allow easy visual inspection of the last print line.
4.5 Form feed mechanism
The platen is driven by astepping motor through an intermediate gear to accom-
plish form feed. When moving the platen in reverse, the stepper motor will move
the platen past the point where printing is to be done, then the platen will be
moved forward to the print line and stopped. This is down to help compensate for
backlash between the gears of the form feed mechanism.
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/m
/Ttv\
/m
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Fig. 4.5
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