APS EPM208 Series Use and care manual

Advanced Printing Systems
Front page
EPM208-LV
EPM208-HS
Technical Reference
EPM208 - Technical reference - Rev. A Page 1

Advanced Printing Systems
Preface
• This manual provides a complete technical information about EPM208 series,
thermal line printer mechanisms.
• If not specified, the data of the present specification are valid for all the types of
printers, when the specification of the printer is different, according to the type, its
specification is described with annotation.
• For customized printers, A.P.S. supplies documentation in addition to the present
specification.
• The present specification is valid also for customized types, where the different
condition has not effects for common data (eg. different length of elec. cables).
• More information is available upon request such as high speed printing
applications and reliability figures.
• A.P.S. reserves the right to make changes to the product, without notice, to
improve reliability, functions or design.
• A.P.S. does not assume any liability arising out of the application or use of the
product or circuits described within.
• The warranty terms of the product are described in a separate document, ask
A.P.S. to obtain this document.
Revision history
Rev.
Index
Date Page/Sec. Description Author
A 23-Oct-03 - Issue MR
- - - - -
EPM208 - Technical reference - Rev. A Page 2

Advanced Printing Systems
TABLE OF CONTENTS
Sec. Page
1. INTRODUCTION ......................................................................................................................... 4
1.1. EPM208 FEATURES .................................................................................................................. 5
2. GENERAL CHARACTERISTICS .................................................................................................. 6
3. THERMAL HEAD AND PRINTING CONFIGURATION .................................................................. 7
3.1. OUTLINES ................................................................................................................................. 7
3.2. THERMAL HEAD ELECTRICAL CHARACTERISTICS .............................................................................. 7
3.3. TIMING CHART ........................................................................................................................... 8
3.4. MAXIMUM CONDITIONS AT 25°C ................................................................................................... 9
3.5. TYPICAL PRINTING CONDITIONS .................................................................................................... 9
3.6. HEATING TIME CALCULATION ...................................................................................................... 10
3.7. THERMISTOR ........................................................................................................................... 10
3.8. PRINT POSITION OF THE DATA .................................................................................................... 11
3.9. OPERATING PRECAUTIONS......................................................................................................... 12
4. STEPPER MOTOR .................................................................................................................... 13
4.1. STEPPER MOTOR TIMING ........................................................................................................... 13
4.2. PAPER FEED SPEED VERSUS VOLTAGE ........................................................................................ 14
5. HOW TO OPTIMIZE SPEED, CONSUMPTION AND MAX. PEAK CURRENT............................... 15
6. SENSORS................................................................................................................................. 16
6.1. DOOR OPEN ............................................................................................................................ 16
6.2. END OF PAPER SENSOR............................................................................................................. 16
7. PIN OUT ASSIGNMENT ............................................................................................................ 17
8. MECHANICAL & HOUSING....................................................................................................... 18
8.1. OVERALL DIMENSIONS, OUTWARD APPEARANCE AND FIXING POINTS ................................................ 18
8.2. MOUNTING PRECAUTIONS .......................................................................................................... 20
9. HANDLING THE EPM................................................................................................................23
9.1. HOW TO OPEN THE COVER GROUP .............................................................................................. 23
9.2. HOW TO LOAD PAPER ROLLS ...................................................................................................... 24
9.3. HOW TO CLOSE THE COVER GROUP CORRECTLY .......................................................................... 25
9.4. HOW TO CUT THE PAPER ........................................................................................................... 26
10. ORDERING CODE..................................................................................................................... 27
EPM208 - Technical reference - Rev. A Page 3

Advanced Printing Systems
1. INTRODUCTION
The EPM208 is a 2 inch, from 3.0V to 9.5V, Easy Loading Printing Module with an integrated paper roll
housing.
The EPM module consists of a set of mechanical and electrical parts, these parts have been designed to have
an high grade of integration between Printer and Housing.
The sections that form the EPM module are described in the following image.
1. Printer mechanism, easy loading type
2. Paper roll housing
3. Cover
4. Lever, for easy opening
5. Roller
6. Tear bar, for paper cutting
7. FPC for electrical connection
5
6
4
7
3
2 1
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1.1. EPM208 features
• Patented Easy loading and Easy Door Opening System
• Ultra compact design
• Up to 80 mm/s printing speed
• Ultra light (95g)
• Starting operating voltage (logic and dots) from 3.0V
• High resolution printing (8 dots/mm)
• Life of 100 million pulses, 50 km
• Low consumption
• Low noise due to its technology (thermal)
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Advanced Printing Systems
2. GENERAL CHARACTERISTICS
Item Specification
Printing method Thermal dot line printing
Number of dots/line 384
Dots density (dot/mm) 8
Printing width (mm) 48 (centred on paper)
Paper width (mm) 58 +0/-1
Paper roll size (mm) Max. Ø49.5 (outside diameter)
Paper feed pitch (mm) 0.0625 (every 1 step of the motor drive signal)
Printing pitch (mm) 0.125 ( every 2 steps of the motor drive signal)
Paper feed tension (gf) 50 or more
Paper hold tension (gf) 80 or more
Dimensions W x D x H (mm) 79.1 x 77.8 x 60
Weight (g) Approx. 95
Head temperature detection Thermistor
Head-up detection Photo-interrupter
(gathered with the paper end sensor)
Paper end detection Photo-interrupter
Operating voltage range (V) EPM208-LV Dots : 3-6.6 / Logic: 3-5.25
EPM208-HS Dots : 5.5-9.5 / Logic: 3-5.25
1.7 A (Head dots)
0.5 A (Motor)
At printing (5V):
(64 dots ON)
50 mA (Head Logic)
0.5 A (Motor)
Current consumption
At paper feeding (5V):
<100 µA (Head Logic)
Recommended Paper JUJO-AF50KS-E (standard grade)
JUJO-AF50KS-E3 (high sensitivity)
Equivalent types can be used
Operating temperature range (°C) 0/+50
Operating humidity (RH%) 20-85 (no condensation)
Storage temperature range (°C) -25/+70
Storage humidity (RH%) 10-90 (no condensation)
Mechanism life
Durability Basic conditions Maximum variations
Thermal head
pulse resistance
100 million
pulses
Abrasion/wear
resistance
50 km of paper
Max. 15% in resistance
value () of any dot, from
its initial value
Cover Group,
Opening/closing
cycle
2000 operations
or more
- Room temp.: 20 ÷ 25 °C
- Head temp.: 65 °C max.
- Rated energy
-
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3. THERMAL HEAD AND PRINTING CONFIGURATION
3.1. Outlines
Heat element structure: 2 heaters/dot
Number of heat elements: 384 dots
Heat element pitch: 0.125 mm
Average resistance: LV - 116 ±10%
HS - 165 ±10%
3.2. Thermal head electrical characteristics
Item Symbol Min. Typ. Max. Unit
Print voltage HS
LV
VH 5.5
3.0
7.2
5.0
9.5
6.6
V
Logic voltage Vdd 3.0 5.00 5.25 V
Logic current I d d - - 55 mA
Input voltage (High) VIH 0.8 Vdd - Vdd V
Input voltage (Low) VIL 0 - 0.2 Vdd V
Data input current (DI) High I IH D I - - 1.0 µA
Data input current (DI) Low I IL D I - - -1.0 µA
STB input current (High) I IH S TB - - 24
(1) µA
STB input current (Low) I IL STB - - -438
(1) µA
Clock input current (High) I IH CLK - - 1.0 µA
Clock input current (Low) I IL CLK - - -1.0 µA
Latch input current (High) IIH L A T - - 1.0 µA
Latch input current (Low) I IL L A T - - -1.0 µA
Data out output voltage (High) V HDO 4.45 - - V
Data out output voltage (Low) VLDO - - 0.05 V
Driver output voltage (Low) VOL - - 2.0 V
Driver output leakage current I OH - - 10 µA/DOT
Clock frequency (Duty 50±5%) f CLK - - 8 MHz
Data setup time t setup DI 70 - - ns
Data hold time t hold D I 30 - - ns
Latch width t w L A T 200 - - ns
Latch setup time t setup L AT 300 - - ns
STB setup time t setup S TB 1500 - - ns
Data out delay time t d D O - - 240 ns
Driver out delay time t do - - 3000 ns
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Advanced Printing Systems
3.3. Timing chart
The following chart gives the timing for driving the print-head:
f CL
K
tdo
tdo
tsetup STB
tw LAT
tsetup LAT
thold DI
tsetup DI
Driver Out
Strobe
\Latch
Data In
Cloc
k
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3.4. Maximum conditions at 25°C
Maximum conditionsItem
LV HS
Unit
Supply energy 0.416 0.367 mJ/dot
Print cycle 3.6 3.1 ms/line
Print head voltage 6.2 8.5 V
Logic voltage 6.5 V
Head temperature 65 °C
Number of dots to be energized
simultaneously1
64 dots
Notes:
• If energy applied to one dot, exceed the maximum value indicated on the above table, the print quality of
this dot may be definitively affected (usually makes a “light” print-out).
• If print cycle is less than 2.5 ms/line (above 50 mm/s) then maximum supply energy value is decreased.
For these applications, please contact A.P.S. for more information.
• When using double-ply paper or special low energy paper, please contact A.P.S. for more information.
3.5. Typical printing conditions
Electrical conditions
Item Symbol
LV HS
Unit
Supply voltage VH 3.6 7.2 V 64 dots fired
Power consumption Po 0.094 0.26 W/dot at the same time
Print cycle S.L.T. 5.0 2.5 2.5 1.7 ms/lin
Energy consumption Eo 0.27 0.14 0.26 0.21 mJ/dot
ON Time Ton 2.91 1.46 1.0 0.80 ms 25 °C
Supply current Io 1.8 2.5 A
The print optical density is then 1.0 minimum with a maximum variation of 0.3. This measurement is done at
the full black pattern by Macbeth densitometer RD-914. Full black pattern is defined as all dots printing
pattern (100% black area) printed under correct paper speed.
1This condition satisfies the print density as defined in section 3.5
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Advanced Printing Systems
3.6. Heating time calculation
The following formula allows to calculate the heating time Ton depending on driving voltage VH:
on
0
0
0
2
comavicl
2
Hav
T=E
P=E*(N * R+R+R+R)
V*R
Where:
E
0is the nominal energy
V
His the driving voltage
R
av is the average resistance
Nis the number of dots energized simultaneously
R
com is the common resistance (0.05 )
R
ic is the driver saturated resistance (10 )
R
lis the lead resistance (10 )
3.7. Thermistor
When performing continuous printing, it is recommended that the supply energy be reduced so that the
substrate temperature monitored through the thermistor will remain below 65°C.
The thermistor specification is the following:
- R25, resistance at 25°C: 30 K±5%
- B value: 3950 K±2%
- Operating temperature: -20°C to +80°C
- Time constant: Max. 30 s (in the air)
Then the resistance value, R, versus temperature, T(in °C), is given by the formula:
R ( T ) = R 25 * eB*( 1
T + 273 -1
25 + 273 )
The dot activation compensation time (1% per degree) is defined as follows:
)
100
25
(1(*
)25(
−
−= °T TT Conon
)25( Con
T°is given in section 3.5.
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Advanced Printing Systems
3.8. Print position of the data
• The first bit of data (dot 1) entered is the first bit of data printed (FIFO), left side of TPH, top view
(gearing side of the printer).
• The table below shows the number of dots driven by each strobe signal.
STB1Dots 321 to 384
STB2+3 Dots 193 to 320
STB4Dots 129 to 192
STB5+6 Dots 1 to 128
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Advanced Printing Systems
3.9. Operating precautions
1- When performing continuous printing, the supply energy should be reduced so that the substrate
temperature, monitored through the thermistor, will remain below 65°C.
2- All strobes signals must be disabled during the power and logic voltage ON/OFF sequence.
3- Do not touch the connector pins with naked hands.
4- The print-head substrate surface is coated with glass, for this reason, mechanical stresses, shocks, dust and
scratches should be avoided to prevent damage.
5- When the print-head operation is completed, print supply voltage (including the charged voltage with
capacitor) should be reduced to the ground level and maintained until next print-head operation.
6- Avoid condensation, if condensation occurs, do not switch ON the print-head power, until condensation
has disappeared.
7- When plugging in and out of the connectors, avoid using excess force as damage may result (Plug in-out
cycle for this connector should not exceeded 20 times). Do not pick up the mechanism by the connectors.
8- Print quality would become degraded if paper or ink residue were stuck on the heat element area. In this
case, clean the print-head with an applicator and alcohol. Do not use the sandpaper as this will destroy the
heating elements.
9- If sticking sound, is heard while printing, please check and adjust the paper feed mechanism and the
electrical pulse program to eliminate the sound.
10- Make sure the paper does not have high abrasion factor, low sensitivity or abnormal chemicals.
11- To avoid surges and voltage losses, VH and GND cable length should be less than 100mm and 47 µF
aluminium capacitor between VH and GND is necessary on customer’s controller board side.
Important precautions
To prevent any dot element damage:
At power up make sure that logic voltage (Vdd) is present simultaneously or before VH.
At power down make sure that VH is at 0 V before removing logic voltage.
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Advanced Printing Systems
4. STEPPER MOTOR
4.1. Stepper motor Timing
The paper feed pitch for stepper motor is 2 steps for one dot-line (0.125 mm). For good print quality it is
advised to keep the current into the windings between two successive dot-lines.
The timing diagram is then as follows:
PHASE 1
PHASE 2
PHASE 3
DOTLINE
123
PHASE 4
STEP
There are four different positions for the stepper motor. The driving is bipolar and can be achieved with
circuits like Rohm BA6845FS, Sanyo LB1836 or LB1838 or Hitachi HA13421. Please refer to the IC’s data
sheet for further information. It is recommended not to exceed 0.2v like voltage drop in the stepper motor
driver circuit.
Coil resistance is 12 , rated current is 300 mA (5V) per phase while feeding at 10mm/s.
In case of high voltage or continuous printing application, contact APS for current application circuitry.
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Advanced Printing Systems
4.2. Paper feed speed versus voltage
The following table gives the maximum paper feed speed versus the stepper motor voltage and duty cycle for
the stepper motor driving. Please note that green-shaded area must be used for EPM208-LV only while
yellow-shaded area must be used for EPM208-HS only. Other values are common to both models.
EPM208-LV or HS
Motor voltage
(V)
Paper feed speed
(mm/s)
Duty cycle
(%)
3 35 100
3.3 37 100
3.6 40 100
4 47 100
4.5 50 80
LV
5 56 60
5.5 59 50
6 62 40
LV/HS
6.5 68 35
7 72 30
7.5 80 25
8 85 20
8.5 90 15
9 90 10
HS
9.5 90 10
Notes:
• To avoid overheating the stepper motor, it is strongly advised to respect the on/off duty cycle as indicated
above (when performing continuos printing and/or paper feeding).
• The maximum period for the ON time is 30 seconds (when the duty cycle is not 100%).
• The Duty cycle depends only on motor voltage, so, for instance: at 6V, the paper feed speed can be less
than 62mm/s, but the duty cycle remains 40%.
To compute the off Time, apply the following formula:
onTime
DutyCycle
onTime
offTime −=
Example : supposing an on Time of 15s, at 6 V, from the table we obtain a duty cycle value of 40%, so:
soffTime 5.2215
100
40
15 =−






=
On the above example, if the EPM208 works consecutively for 15 seconds, it must rest for 22.5s to allow the
motor to cool down.
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Advanced Printing Systems
5. HOW TO OPTIMIZE SPEED, CONSUMPTION AND MAX. PEAK CURRENT
The printing speed is always a compromise between 3 parameters :
• Paper feed speed (function of voltage).
• Head activation time Ton (function of voltage and temperature).
• Maximum peak current available (function of voltage and maximum number of dots simultaneously
activated and directly related to power supply capabilities).
For a given voltage it is easy to determine the maximum paper feed speed (MaxPFS), as indicated on the table
of section 4.1. So, if the two others parameters (current and Ton) are not limiting, maximum paper feed speed
(MaxPFS) becomes equal to maximum printing speed (MaxPS).
MaxPFS gives a time (by inverting) known as S.L.T. (scanning line time). In this time, the head must be
activated. If this time is not long enough, MaxPS will be subsequently affected.
Then, the method of driving the head is a critical point in a thermal printing application. There are two basic
methods to limit the current in the head:
1. Divide the head into fixed blocks (by 64 dots for example) and use the strobe lines to control the blocks to
be activated. This method is easy implement, however the printing speed will be very slow because the
MaxPS will be the invert of the activation time multiplied by the number of blocks the head is divided
into.
Example: at 6 V with the EPM208-HS, the activation time is 1.0ms*(7.22/62) = 1.44ms. If the maximum
current available for the head is 2.3A, the maximum number of dots to be simultaneously activated will
be 2.3A/(6V/165)≅64 dots. So the number of activation per S.L.T. will be 384/64=6, giving a S.L.T. of
6*1.44ms=8.64ms. Therefore, the MaxPS will be 1/(8*8.64*10-3) = 14.5 mm/s while MaxPFS is
62mm/s. So, in this case, we find a big difference between printing speed and paper feed speed.
2. Divide the head dynamically performed by counting the number of dots actually activated. The software
counts the actual number of “black” dots while loading the print-head. When the number of black dots
reaches the maximum value (in this example the value will be 64) the software fills the remaining dots
with “0” and activates the strobes line. As a result the activation is the maximum number of black dots
allowed, by the given value, thereby optimizing the number of times the head needs to be activated.
Printing standard text, the average number of black dots is generally less than 64 and sometimes reach
128.
Example: referring to the above example, the MaxPS is multiplied by 6, or sometimes by 3. In fact, if we
assume that 30% of the lines contain from 64 to 128 black dots, the average MaxPS will be 62*0.7 +
(14.5*3)*0.3 = 56.5 mm/s, getting very close to the MaxPFS and optimizing all the parameters.
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Advanced Printing Systems
6. SENSORS
6.1. Door open
In order to optimize and decrease the number of elements of the EPM, the opto sensor performs dual
functions - door open and end of paper detection. The shape and distance from the opto sensor to the paper is
designed in a way that as soon as the door is opened, the distance between the paper and the sensor increases,
and this causes the end of paper sensor to trigger.
6.2. End of paper sensor
The EPM208 has an end of paper sensor achieved by a photo-transistor. Arrange the circuitry so that no
energy is applied to the head when there is no paper. If the head is energized when there is no paper and the
head is in the down position, then both roller and head may be strongly damaged.
OPTO characteristics:
Item Symbol Conditions Min. Typ. Max. Unit
Forward voltage
(photodiode)
VFI
F = 10mA - - 1.3 V
Reverse current IRV
r= 5V - - 10 µA
Output dark current ICEO V
CE= 10V - - 0.2 µA
Light current ILV
CE = 5V
IF = 10mA
180 - 660 µA
Rise time TRV
CE = 2V
IC= 0.1 mA
RL = 1K
- 30 - µs
Fall time TF- 25 - µs
One possible interfacing is as follows:
180
27K
+5V
+5V
VOUT
VOUT > 3.5V ---> No Paper
VOUT < 2.5V ---> Paper
PRINTER SIDE
USER SIDE
(To analog input)
EPM208 - Technical reference - Rev. A Page 16

Advanced Printing Systems
7. PIN OUT ASSIGNMENT
One flexy cable is gathering all signals. The pitch at the end of the flexy is 1mm.
FPC connector can be: JST 27FMN-BMT-TF
EPM208-LV-HS
Pin number Signal name Function
1 CO Collector of photo-transistor
2 VF Anode of photo-sensor
3 L-GND Gnd for logic
4 VH Dot-line voltage
5 VH Dot-line voltage
6 DI Data input
7 /LAT Latch (active Low)
8 CLK Serial clock
9 Vdd Logic voltage
10 /STB1Strobe (acltive Low)
11 GND Gnd for dot-line
12 GND Gnd for dot-line
13 TM Thermistor first terminal (second is Gnd)
14 GND Gnd for dot-line
15 GND Gnd for dot-line
16 /STB2+3 Strobe (acltive Low)
17 CLK Serial clock
18 /STB4Strobe (acltive Low)
19 GND Gnd for dot-line
20 GND Gnd for dot-line
21 /STB5+6 Strobe (acltive Low)
22 Vdd Logic voltage
23 DO Data output
24 VH Dot-line voltage
25 VH Dot-line voltage
26 SM4 Fourth phase of stepper motor
27 SM3 Third phase of stepper motor
28 SM2 Second phase of stepper motor
29 SM1 First phase of stepper motor
Note: For pin #1 position, refer to the drawings at the end of this document
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8. MECHANICAL & HOUSING
8.1. Overall dimensions, outward appearance and fixing points
Overall dimensions:
See attached drawings for overall dimensions and recommended screws.
3D-IGES file, for mechanical details, is available upon request, ask APS for more information.
Standard outward appearance:
Housing colour is black, Cover is transparent uncoloured, Lever is green transparent, refer to photo on front
page of the present document.
Fixing points:
The mechanism has to be fixed using the fixing points provided for this purpose.
There are two possibilities:
• Using points 1-2-4-5 (all of them simultaneously).
• Using points 3-4-5 (all of them simultaneously).
To avoid any kind of deformation or distortion, a flat surface for contact areas is required, if not, the print
quality and printer's life will be drastically reduced.
Points 3-4-5 are on the same plane, at the mounting base of the EPM.
Points 1-2 are on the same plane and have a 19.2mm distance from the mounting base plane (see also attached
drawing).
The image below, shows the matching areas to be used for fixing, they are highlighted in red colour.
Bottom view of EPM208
54
3
21
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8.2. Mounting precautions
Orientation according to figure A-B is to be preferred, reliability and life tests have been based only
according to this orientation.
Alternatively, it is possible to choose different orientation angles as shown in figures C-D-E.
EPM208 - Technical reference - Rev. A Page 20