ROHM KF2004

KF2004-GK42A
Printheads
Compact medium speed thick film thermal
printhead (8dots / mm)
KF2004-GK42A
KF2004-GK42A is suitable for devices, such as high-speed POS and label printer applications, that require thermal
printheads capable of higher printing rates. Improved power circuit design means that with heavier current it is possible to
print at speeds as high as 150 mm/s. The GK Series is the thus ideal for label printers that need high printing rates.
!Applications
POS terminals, Label printers, CAT terminals, Multi-purpose small-sized printers
!Features
1) Using a special compact partial glaze and new heating element structure, achieves high-speed printing at 150 mm/s.
2) The use of the newly developed highly-durable conductive protective film has improved countermeasures against
static electricity.
3) The VH and GND sections of the power circuitry have been strengthened so that heavier current can be applied.
4) Ultra small connectors, designed to conform with FFCs, and miniature driver chips have been used. Although the
resulting printheads are surprisingly compact and lightweight, they can be used with large platens of up to 20 mm in
diameter.
5) One rank resistance value of 800Ω ± 3% eliminates the inconvenience of rank selection.
6) 2-inch, 3-inch and 4-inch series are available.
!External dimensions (Units : mm)
Max.1.7
Dot #864
(5.1)
Dot #1
No.28
M
ax
.φ
20
.0
Max.17.5
2.6±0.1
118
108 (Effective Print Width)
No.1
4±0.2
Exposed Conductor Side
10.2
5.1±0.1
110±0.2
Insert Direction
Connector
2-M3 (Effective Depth 3)
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KF2004-GK42A
Printheads
!Equivalent circuit
VH
GND
1, 2, 3, 4,
25, 26, 27, 28
DOT #864
4
STB4
STB3
STB2
STB1
LAT
DI
CLK
DO
V DD
TM
TM
DOT #1
11, 12, 13, 14,
15, 16, 17, 18, 19
3
2
1
144 OUTPUTS EACH
22
23
8
9
7
LATCH REGISTER
24
SHIFT REGISTER
6
5
21
10
THERMISTOR
30kΩ B:3950k
20
CONNECTOR
Fig.1
!Pin assignments
No.
Circuit
No.
Circuit
1
VH
15
GND
2
VH
16
GND
3
VH
17
GND
4
VH
18
GND
5
DO
19
GND
6
CLK
20
TM
7
LAT
21
VDD
8
STB2
22
STB4
9
STB1
23
STB3
10
TM
24
DI
11
GND
25
VH
12
GND
26
VH
13
GND
27
VH
14
GND
28
VH
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KF2004-GK42A
Printheads
!Timing chart
tw CLK
CLOCK (CLK)
t setup DI
t hold DI
DATA IN (DI)
"High":BLACK
"Low" :WHITE
td DO
DATA OUT (DO)
"High":BLACK
"Low" :WHITE
t hold LAT
t setup LAT
LATCH (LAT)
"High":HOLD
"Low" :THROUGH
tw LAT
t setup STB
STROBE (STB)
tdo
tdo
DRIVER OUT
Fig.2
!Characteristics
Symbol
Typical
Unit
Effective printing width
−
108
mm
Dot pitch
−
0.125
mm
Parameter
−
864
dots
Rave
800
Ω
Applied voltage
VH
24.0
V
Applied power
PO
0.59
W/dot
Total dot number
Average resistance value
Print cycle
SLT
1.0
ms
Pulse width
TON
0.34
ms
Maximum number of dots energized simultaneously
−
432
dots
Maximum clock frequency
−
4
MHz
Maximum roller diameter
−
φ20.0
mm
Running life / pulse life
−
50/5×107
km/pulses
Operating temperature
−
5~45
°C
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KF2004-GK42A
Printheads
!Electrical characteristic curves
0.8
0.8
1.8
Paper : KF50-HDA (OJI)
0.7
1.4
0.5
0.4
0.3
1.2
1.0
0.8
0.6
0.2
0.4
0.1
0.2
0
0
1
2
3
4
5
SCANNING LINE TIME (ms/line)
0.6
ENERGY (mJ/dot)
OPTICAL DENSITY
0.6
ENERGY (mJ/dot)
SLT : 1.00ms/line
1.6
0.7
0.0
0.00
0.4
0.3
0.2
0.1
0.05
0.10
0.15
0.20
0.25
0.30
ENERGY (mJ/dot)
Fig.3 Adaptive speed chart
0.5
Fig.4 Representative density curve
0
0
1
2
3
4
5
SCANNING LINE TIME (ms/line)
Fig.5 Maximum energy curve
180
160
RESISTANCE : (kΩ)
140
120
100
80
60
40
20
0
−20 −10
0
10
20
30
40
50
60
70
TEMPERATURE : (°C)
Fig.6 Thermistor curve
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