PyESCPOS 0.4

Support for Epson ESC/POS printer command system.

PyESCPOS

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A Python support for Epson© ESC/POS® compatible printers. Read more at Epson ESCPOS Command Reference.

The ESC/POS® is a standard that every manufacturer work on and modify to suit their needs. That way, a sequence of commands in one printer does not necessarily works (or does not work as expected) on another. At a distance, you can say that all those tricky commands are identical from model to model (a standard), but when you look just a little bit more deeper, you quickly realize that they can be completely different, even between models belonging to the same manufacturer.

This project aims to simplify the usage of printers, seeking for a lowest common denominator between needed features and providing implementations that meet this minimum for known models, so you do not have to modify the application code.

Current Implementations

Current implementations was tested against following hardware:

Manufacturer	Models	Firmware Versions	Notes
Bematech S/A	MP-2800 TH	2.2.1BQL
Bematech S/A	MP-4200 TH	1.3, 1.6
Control iD	Print iD Touch	1.3.0
Epson	TM-T20	1.14
Elgin	Elgin i9	1.03.20, 1.03.24, 1.03.31
Elgin	Elgin i7	1.00.08
Elgin	Elgin RM-22	1.00.09	Elgin RM-22 portable thermal mini printer
Nitere	NPDV-1020		Multifunction Terminal model TMF-101/IG (an alias for CB55-C model)
Unknown OEM	CB55-C	1.3.5	Embedded in Nitere NPDV-1020 (model TMF-101/IG)
Urmet Daruma	DR700 L/H/M and DR700 L-e/H-e	02.51.00, 01.20.00, 01.21.00
Urmet Daruma	DR800 L/H	03.13.01

You can get a list of all available implementations with the following snippet:

from escpos import helpers

for impl in helpers.find_implementations(sort_by='model.name'):
    print('{:.<25} {}'.format(impl.model.name, impl.fqname))

Which produces an output similar to:

Bematech MP-2800 TH...... escpos.impl.bematech.MP2800TH
Bematech MP-4200 TH...... escpos.impl.bematech.MP4200TH
CB55-C................... escpos.impl.unknown.CB55C
Daruma DR700............. escpos.impl.daruma.DR700
Daruma DR800............. escpos.impl.daruma.DR800
Elgin I7................. escpos.impl.elgin.ElginI7
Elgin I9................. escpos.impl.elgin.ElginI9
Elgin RM-22.............. escpos.impl.elgin.ElginRM22
Epson TM-T20............. escpos.impl.epson.TMT20
Generic Daruma........... escpos.impl.daruma.DarumaGeneric
Generic ESC/POS.......... escpos.impl.epson.GenericESCPOS
Generic Elgin............ escpos.impl.elgin.ElginGeneric
Nitere NPDV-1020......... escpos.impl.nitere.NitereNPDV1020
Print iD Touch........... escpos.impl.controlid.PrintIdTouch

Usage Examples

Network TCP/IP Example

You can connect to your printer through network TCP/IP interface:

from escpos import NetworkConnection
from escpos.impl.epson import GenericESCPOS

conn = NetworkConnection.create('10.0.0.101:9100')
printer = GenericESCPOS(conn)
printer.init()
printer.text('Hello World!')

Serial Example

Support for Serial connections is optional. If you need it you should have PySerial library installed. You may do it through PIP issuing pip install PyESCPOS[serial].

Here is how you can make a Serial connection:

from escpos import SerialConnection
from escpos.impl.epson import GenericESCPOS

# connect to port 'ttyS5' @ 9600 Bps, assuming RTS/CTS for handshaking
conn = SerialConnection.create('/dev/ttyS5:9600,8,1,N')
printer = GenericESCPOS(conn)
printer.init()
printer.text('Hello World!')

Bluetooth Example

Support for Bluetooth (via RFCOMM) connection is optional. If you need it you should have PyBluez library installed. One option may be installing PyESCPOS through PIP issuing pip install PyESCPOS[bluetooth].

Here is how you can make a Bluetooth connection:

from escpos import BluetoothConnection
from escpos.impl.epson import GenericESCPOS

# uses SPD (service port discovery) services to find which port to connect to
conn = BluetoothConnection.create('00:01:02:03:04:05')
printer = GenericESCPOS(conn)
printer.init()
printer.text('Hello World!')

If you know in which port you can connect beforehand, just pass its number after device address using a forward slash, for example 00:01:02:03:04:05/4, will connect to port 4 on 00:01:02:03:04:05 address.

USB Example

Support for USB connections is optional. If you need it you should have PyUSB library installed. You may do it through PIP issuing pip install PyESCPOS[usb]. Be aware for printers with more than one USB interface, so you may have to configure which interface is active.

Here is how you can make an USB connection:

from escpos.ifusb import USBConnection
from escpos.impl.elgin import ElginRM22

conn = USBConnection.create('20d1:7008,interface=0,ep_out=3,ep_in=0')
printer = ElginRM22(conn)
printer.init()
printer.text('Hello World!')

File Print Example

This printer “prints” just into a file-handle. Especially on *nix-systems this comes very handy. A common use case is when you have a parallel port printer or any other printer that are directly attached to the file system. Note that you may want to stay away from using USB-to- Parallel-Adapters since they are extremely unreliable and produce many arbitrary errors.

from escpos import FileConnection
from escpos.impl.elgin import ElginI9

conn = FileConnection('/dev/usb/lp1')
printer = ElginI9(conn)
printer.init()
printer.text('Hello World!')
print(printer.device.output)

Dummy Print Example

The Dummy-printer is mainly for testing- and debugging-purposes. It stores all of the “output” as raw ESC/POS in a string and returns that.

from escpos import DummyConnection
from escpos.impl.epson import GenericESCPOS

conn = DummyConnection()
printer = GenericESCPOS(conn)
printer.init()
printer.text('Hello World!')
print(printer.device.output)

Printing Barcodes

There is a default set of parameters for printing barcodes. Each ESC/POS implementation will take care of the details and try their best to print your barcode as you asked.

from escpos import barcode
from escpos import SerialConnection
from escpos.impl.epson import GenericESCPOS

conn = SerialConnection.create('COM1:9600,8,1,N')
printer = GenericESCPOS(conn)
printer.init()
printer.code128(
        '0123456789',
        barcode_height=96,  # ~12mm (~1/2")
        barcode_width=barcode.BARCODE_DOUBLE_WIDTH,
        barcode_hri=barcode.BARCODE_HRI_BOTTOM
    )

printer.lf()

printer.ean13(
        '4007817525074',
        barcode_height=120,  # ~15mm (~9/16"),
        barcode_width=barcode.BARCODE_NORMAL_WIDTH,
        barcode_hri=barcode.BARCODE_HRI_TOP
    )

printer.cut()

The barcode data you pass as a parameter should be complete including check digits and any other payload data required that makes that data valid for the symbology you’re dealing with. Thus, if you need to print an EAN-13 barcode, for example, you need to provide all thirteen digits.

Configuring Resilient Connections

Network (TCP/IP) and Bluetooth (RFCOMM) connections provided by PyESCPOS both use a simple exponential backoff algorithm to implement a (more) resilient connection to the device. Your application or your users can configure retry parameters through environment variables (or files):

• ESCPOS_BACKOFF_MAXTRIES (int > 0, defaults to 3) Number of tries before give up;

• ESCPOS_BACKOFF_DELAY (int > 0, defaults to 3) Delay in seconds between retries;

• ESCPOS_BACKOFF_FACTOR (int > 1, defaults to 2) Multiply factor in which delay will be increased each retry.

This library may use python-decouple if available to grab those configuration values from environment variables or from a settings file, depending on how you have configured decouple. If not, it falls back to standard lib os.getenv.

More Information

You will find more information in the PyESCPOS wiki pages.

You are Welcome to Help

Here is how you setup a development enviroment:

git clone [e-mail]:base4sistemas/pyescpos.git
cd pyescpos
python -m venv .env_escpos
source .env_escpos/bin/activate
pip install -r requirements/dev.txt
tox

If you gonna work with a specific type of connection (eg. Bluetooth or Serial) you may use requirements/bluetooth.txt or requirements/serial.txt. Have a look inside requirements/ directory for the options available.

Acknowledgement

This project is inspired on Manuel F. Martinez work for python-escpos implementation, among other projects, whose specific bits of work (available here on Github and many other open-source repositories) has helped so much.

Disclaimer

Please, read this disclaimer.

None of the vendors cited in this project agree or endorse any of the patterns or implementations. Its names are used only to maintain context.