Dymo LabelWriter 400 Series Product manual

LabelWriter 400 Series Printers
Technical Reference Manual
Includes LabelWriter 400, LabelWriter 400 Turbo, LabelWriter Twin Turbo, and
LabelWriter Duo Printers

LabelWriter 400 Series Technical Reference Manual Page 2
© 2002-2008 Sanford, L.P. All Rights Reserved.
LabelWriter and DYMO are registered trademarks of Sanford, L.P. All other trademarks are the property of their
respective holders.
Legal Notice:
Sanford, L.P. has used reasonable efforts to ensure that the information provided by Sanford,
L.P. in this manual is accurate and up to date, but Sanford, L.P. reserves the right to make
changes or corrections and does not warrant that any of the information is accurate or complete.
Sanford, L.P. hereby disclaims all liability, and makes no warranties (including any implied
warranties of merchantability or fitness for a particular purpose), in relation to the manual or the
information it contains. Sanford, L.P. provides limited or no support for the activities
referenced in this manual. You expressly understand and agree that Sanford, L.P. shall not be
liable for any direct, indirect, consequential, incidental, special, punitive or exemplary damages
(including but not limited to lost profits, loss of data or damage to hardware or software) arising
from your use or inability to use the information in this manual, even if Sanford, L.P. has been
informed of the possibility of such damages.

© 2002-2008 Sanford, L.P. Page 3
Table of Contents
About the LabelWriter 400 Series Printers......................................................................... 7
The Print Head................................................................................................................ 7
Printer Commands and Control .......................................................................................... 8
Print Data........................................................................................................................ 8
Data Synchronization...................................................................................................... 8
Label Positioning............................................................................................................ 9
Top-of-Form Sync .......................................................................................................... 9
Label Length................................................................................................................... 9
Label-Movement Commands ....................................................................................... 10
Form Feed Command (<esc> E)............................................................................... 10
Short Form Feed Command (<esc> G)..................................................................... 10
Skip “n” Lines Command (<esc> f 1 n).................................................................... 10
The Status Byte............................................................................................................. 10
Optimization of Throughput......................................................................................... 11
Self-Test Capability...................................................................................................... 11
Barcode and Graphics Print Mode................................................................................ 11
Power Requirements......................................................................................................... 12
AC Adapter............................................................................................................... 12
PCB Input Power ...................................................................................................... 12
Connector (JP2) ........................................................................................................ 13
USB Printer Interface........................................................................................................ 14
USB Vendor ID......................................................................................................... 14
USB Product IDs....................................................................................................... 14
Printer Commands ............................................................................................................ 15
Commands Sent to the Printer...................................................................................... 15
<esc> B n Set Dot Tab....................................................................................... 15
<esc> D n Set Bytes per Line............................................................................. 15
<esc> L nl n2 Set Label Length............................................................................ 16
<esc> E Form Feed............................................................................................. 16
<esc> G Short Form Feed ................................................................................... 16
<esc> q n Select Roll (Twin Turbo printer Only) ................................................. 16
<esc> A Get Printer Status.................................................................................. 17
<esc> @ Reset Printer.......................................................................................... 17
<esc> * Restore Default Settings ...................................................................... 17
<esc> f 1 n Skip "n" Lines................................................................................... 17
<esc> V Return Revision Letter/Number............................................................ 18
<syn> nl..nx Transfer Print Data............................................................................ 18
<etb> nl..nx Transfer Compressed Print Data....................................................... 18
<esc> h Text Speed Mode.................................................................................. 18
<esc> i Barcode and Graphics Mode.................................................................... 18
<esc> c Set Print Density Light.......................................................................... 18
<esc> d Set Print Density Medium..................................................................... 19
<esc> e Set Print Density Normal...................................................................... 19
<esc> g Set Print Density Dark.......................................................................... 19

LabelWriter 400 Series Technical Reference Manual Page 4
<esc> y Set print resolution to 300x300............................................................. 19
<esc> z Set print resolution to 203x300............................................................. 19
Appendix A Data Compression........................................................................................ 21
Appendix B Printing to the LabelWriter Duo Tape Printer .......................................... 23
Command Language..................................................................................................... 23
<esc> B – Dot Tab.................................................................................................... 23
<esc> D – Bytes per Line.......................................................................................... 23
<syn> – Print Data.................................................................................................... 24
<esc> C – Set Tape Type.......................................................................................... 24
<esc> E – Cut Tape................................................................................................... 25
<esc> A – Get Status................................................................................................. 25
Appendix C Debugging Printer Output......................................................................... 27

© 2002-2008 Sanford, L.P. Page 5
NOTE: The purpose of this manual is to serve as a reference to knowledgeable developers
wishing to communicate directly with the LabelWriter printer without the use of printer drivers.
Because the printer is a raster-based printer, this is not a simple task, and Sanford, L.P. reserves
the right to limit development support for such implementations.

LabelWriter 400 Series Technical Reference Manual Page 6

© 2002-2008 Sanford, L.P. Page 7
About the LabelWriter 400 Series Printers
The LabelWriter 400 series printers (LabelWriter 400, 400 Turbo, Twin Turbo, and Duo) are
high-performance, low-cost printers used for printing mailing labels, postage, file folder labels,
bar code labels, and more. The printers have a 57 mm wide, 300-dpi print head and a 63 mm
wide paper path. The LabelWriter Twin Turbo printer has two side-by-side label printing
mechanisms in a single printer. The LabelWriter Duo printer has a label printing mechanism as
well as a tape-printing mechanism that can print continuous-length labels in several different
widths (6 mm, 9 mm, 12 mm, 19 mm, or 24 mm), using a 96-dot or 128-dot, 180-dpi print
head1.
The 57 mm wide thermal print head uses 672 individually addressable dots to form individual
raster lines of data at 300 dpi. Because they use specially treated, heat-activated paper, the
printers require no ink, toner, or other refills.
All 400 series printer models connect to a host computer through a standard full-speed USB
2.0-compatible interface. When used as raster-only printers, there are no built-in fonts. The host
computer is responsible for sending commands and data to the printer to form each individual
raster line of data. This is generally performed by printer drivers in the host computer that
convert the image of the label into the proper command and data stream required by the printers.
The Print Head
The print head prints the image onto the label by heating a row of resistive elements; this
blackens the thermally sensitive label material. These 672 resistive elements are .085 mm
square and are spaced at 300 per inch on the print head. To print a line, the control electronics
load the desired data into a serial shift register. This shift register has one register for each print
element. A "1" in a register causes the corresponding dot to be printed; a "0" leaves the dot
blank.
The darkness or density of the image depends upon the amount of heat applied to the label
material. The heat depends upon both the temperature of the print head and the amount of
energy applied to the resistive elements. The energy applied to the resistive elements depends
upon the voltage applied and the length of time that the voltage is applied. In order to maintain a
constant density, the control electronics measure the print voltage and the head temperature
before each print cycle, and then calculate the required print strobe time.
The power supply is designed to handle printing an average of 37% of the total dots per line at
full speed. If the voltage drops below 19.3 volts at the print head, printing is suspended until the
power supply recovers to 21 volts.
In order to protect the print head from excessive heat, the control electronics halt printing if the
print head temperature exceeds 80° C. Printing resumes when the print head cools to 55° C.
1The DYMO LabelWriter Duo printer initially shipped with a 96-dot print head for the tape-printing mechanism.
This has been replaced with a 128-dot print head.

LabelWriter 400 Series Technical Reference Manual Page 8
Printer Commands and Control
The printers support two types of commands through the USB interface: data commands and
USB interface commands. As with all USB printers, data commands for imaging a page are
provided to the printer through the Bulk OUT endpoint. For information on USB interface
commands, refer to the Universal Serial Bus Device Class Definition for Printing Devices
document.
Data commands for printing consist of print data and ESC commands. Print data is used to
define the dot pattern to print for each raster line. ESC commands (commands preceded by an
ASCII <esc> character, 0x1b) are commands that change printer parameters, such as margins
and raster line offsets. All printer parameters are set to specific default values by a power-on
reset or software reset command from the host computer. Parameters can be modified by the
host computer at any time and will take effect as soon as the modifications are sent.
Print Data
Print data is encoded in strings of 8-bit bytes, preceded by a single synchronization character.
Two print line commands specify whether the data format is uncompressed or compressed.
Uncompressed data is preceded by an ASCII <syn> character (0x16), and compressed data is
preceded by an ASCII <etb> character (0x17). Appendix A describes the compressed data
format.
The Bytes-per-Line variable controls the number of bytes required for each line of print data.
The default value for all 400 series printers is 84 bytes per line (84 * 8 = 672, the number of
dots in the print head). The host computer can send fewer bytes than the maximum by
preceding the print data with the Set Bytes per Line command (<esc> D n, where n is the
number of bytes). The control electronics do not check the validity of the new value. Therefore,
it is the responsibility of the host software to send only those values which are valid for the
width of the print head.
In addition to sending fewer bytes per line, the host computer also has the ability to adjust the
starting point on a line by using the Set Dot Tab command (<esc> B n, where n is the starting
byte number; valid values are 0-83). If the host computer modifies the starting byte, the number
of bytes per line must be adjusted downward by a corresponding amount. The control
electronics do not check the validity of the dot tab against the bytes per line. Therefore, it is the
responsibility of the host software to send correct combinations of these two variables.
Both the dot tab variable and the bytes-per-line variable are held by the control electronics until
they are changed by a new command sequence or are reset to default values by a power-on reset
or a software reset command.
Data Synchronization
After the printer receives a <syn> or <etb> character, it takes the following n value and puts it
into the RAM buffer. The value for n is determined by the number of bytes required to specify a
full line of data. This value is affected by the setting for Bytes per Line and, in the case of
<etb>, the data compression of the bit pattern. It is important to note that the n values which
follow <syn> or <etb> characters are interpreted only as graphical data. This means that

© 2002-2008 Sanford, L.P. Page 9
additional <syn>, <etb>, or <esc> characters will be treated as print line data, representing
pixels to print, until the required number of bytes for the print line are received.
The character received by the printer after the last data character should be an <esc> character,
denoting a command sequence, or a <syn> or <etb> character, denoting another line of raster
data. Any other characters are ignored.
To reset the printer after a synchronization error or to recover from an unknown state, the host
computer needs to send at least 85 continuous <esc> characters to the printer. This 85-character
sequence is required in case the printer is in a mode in which it expects a raster line of data. The
85 <esc> characters exceed the default number of bytes required for a full line of raster data
(84); this ensures that the printer looks for an ESC command.
Note: A minimum of 85 <esc> characters are required, as this is one more than the longest
possible string of data bytes that the printer could encounter.
Label Positioning
A motor-driven platen, which acts as a pinch roller, controls label movement within the printer.
The control electronics track the logical position on a label by counting motor steps. An infrared
LED photocell detects the top-of-form sense hole that is located between labels. The sense hole
re-syncs the logical counter to a known value that corresponds to the number of motor steps
between the sensor and the cutter bar. Top-of-form position (the inter-label gap under the cutter
bar) is reached when the logical counter decrements to zero. The first motor step after top-of-
form position reloads the down counter with a value representing the hole-to-hole length of the
current label stock.
Top-of-Form Sync
The logical position counter is not initialized at power up. Label position is always assumed to
be correct due to the self re-syncing described above. If an Out of Paper condition is detected at
power up, an Advance to Top-of-Form command is issued and the stepper motor will advance
until either a top-of-form sense hole is detected, causing a re-sync, or until the counter has
advanced the equivalent of one full label. This Load Paper condition also causes the stepper
motor to step at a slower rate to help overcome the frictional drag caused by the print head
rubbing directly on the rubber platen.
Label Length
At power up, the label length variable is set to a default value of 3058 (in 300ths of an inch
units), which corresponds to approximately 10.2 inches. The Set Label Length command
sequence (<esc> L nl n2) allows the host software to change the label length variable to
accommodate longer lengths. If longer length labels are used, it is the responsibility of the host
computer to load (and/or re-load) the required label length variable every time the printer is
reset by a power-on reset or a software reset.
When the label length variable is set to any negative 2 byte integer value (0x8000-0xFFFF), it
allows for the use of continuous form paper. In the continuous form mode, the Form Feed

LabelWriter 400 Series Technical Reference Manual Page 10
command (<esc> E) is changed to feed enough dot lines to allow for the last line of print data to
extend past the printer tear-bar.
The 400 series printers do not compare the label length variables sent by the host with the actual
length of the currently loaded label stock. The printers only use the information provided to
maintain the logical position counter. In addition, the printer does not check for inter-label gap
when printing. It is the responsibility of the host computer to avoid overrunning the label area.
Label-Movement Commands
There are three label-movement commands implemented in the LabelWriter: Form Feed, Short
Form Feed and Skip “n” Lines. These commands operate as follows.
Form Feed Command (<esc> E)
This command causes the control electronics to skip lines until the logical position counter has
decremented to zero, or the printer electronics sense the top-of-form hole or mark. The printer
then advances the label just beyond the tear-bar. This command can be used after every label or
combined with the Short Form Feed command (see below) to optimize printing by executing the
Form Feed command only at the end of a multi-label print job.
Short Form Feed Command (<esc> G)
Use this command when printing multiple labels. The normal Form Feed command also works
for this purpose. However, using the Short Form Feed command optimizes the printer and
minimizes print time by eliminating the need to reverse feed after advancing the top-of-form
mark to the tear bar, as the normal Form Feed command does. The Short Form Feed command
advances the printed label just far enough to place the next label in position for printing.
Because of the mechanics of the printer, the preceding label will still be partially within the
label exit slot. For a label to be in tear-off position, you must use the normal Form Feed
command (<esc> E).
Skip “n” Lines Command (<esc> f 1 n)
Use this command to force the LabelWriter printer to advance the number of lines
corresponding to the variable n (0 to 255 lines). This command is put into the data buffer along
with the print data so that it will take effect at the appropriate point in the data stream. The Skip
“n” Lines command is executed only one time per instance and must be re-issued each time a
skip is desired.
The Status Byte
The LabelWriter printer reports a status byte with several bits dedicated to reporting its current
state.

© 2002-2008 Sanford, L.P. Page 11
The host requests the status byte from the printer by issuing an ESC A command. The bits in the
returned status byte are described below:
Bit 0 (Ready Bit)
This bit is always returned as a 1.
Bit 1 (Top-of-Form)
This bit is returned as a 1 if the printer is in top-of-form position. Otherwise, this bit is returned
as a 0.
Bit 2 (reserved)
Bit 3 (reserved)
Bit 4 (reserved)
Bit 5 (Out of Paper)
This bit is returned as a 1 if the printer is out of paper. Otherwise, this bit is returned as a 0.
Bit 6 (Paper Jam)
Bit 7 (Error)
This bit is also sent when an out of paper condition is detected.
Optimization of Throughput
To achieve optimal performance, the data transfer from the host to the printer should be kept as
short as possible. The communication protocol was designed to allow the data to be transferred
with only one overhead byte per dot line. Command sequences, such as Set Dot Tabs or Set
Bytes per Line, should be sent only when a change is desired. The Dot Tab and Bytes per Line
commands should be used to reduce the number of bytes transmitted. The Form Feed command
should be used after transmitting the last dot line to be printed.
Self-Test Capability
The printers include a self-test capability in the form of canned print patterns. To activate the
self-test, press the form-feed button and hold it down for approximately 10 seconds. The self-
test will start printing a repeating series of test patterns. To stop the self-test, press the form-feed
button a second time.
Barcode and Graphics Print Mode
For better accuracy of dot placement and sizing, the LabelWriter 400 series printers incorporate
a feature which allows the host computer to specify a slower, Barcode and Graphics print mode.
This mode may improve print quality of smaller barcodes and some graphic images.

Power Requirements
The LabelWriter 400 series printers are normally supplied with an external, universal
(100 – 240 VAC) AC power adapter. For OEM applications, a DC voltage can also be
supplied to the main printed circuit board (PCB) of the printer using the JP2 connector.
Note: The printers have been tested and certified for EMC and safety requirements using
the supplied AC adapter. Supplying a non-DYMO power source may change the EMC
and safety certifications.
Input power is variable based on the amount of information printed and the duty cycle of
the label printing. The ratings below are based on normal printer usage, except where
specified.
The printer driver (print commands from the host computer) controls some printing
parameters and will change maximum power usage.
AC Adapter
DYMO part number 93447 (60 W)
Input voltage 100 – 240 VAC, 50/60 Hz, 1.6 Amps
Output voltage 24 VDC, 2.5Amps
PCB Input Power
All LabelWriter 400 series printers have an input voltage of 24 VDC, +/- 5%. Their
power requirements are as follows.
LabelWriter 400 and 400 Turbo Printers
Input current (idle) 0.040 Amps
Input current (typical) 1.75 Amps
Input current (max.) 3.3 Amps based on printing a shipping label (30256) with a
maximum-size filled rectangle, after print head temperature
increases above ambient temperature.
At nominal print head temperature: 2.7 A
In graphics mode: 1.6 A
LabelWriter 400 Series Technical Reference Manual Page 12

LabelWriter Twin Turbo Printer
Input current (idle) 0.026 Amps
Input current (typical) 0.975 Amps (text only)
Input current (max.) 3.3 Amps based on printing a shipping label (30256) with a
maximum-size filled rectangle, after print head temperature
increases above ambient temperature.
At nominal print head temperature: 2.9 A
In graphics mode: 1.6 A
LabelWriter Duo Printer
Input current (idle) 0.052 Amps
Input current (typical) 1.1 Amps (text only)
Input current (max.) 3.3 Amps based on printing a shipping label (30256) with a
maximum-size filled rectangle, after print head temperature
increases above ambient temperature.
At nominal print head temperature: 3.0 A
Note: The input current is ramped up as the 24 V is applied to the input to limit in-rush
current (there is a 2200µF filter capacitor at the input). After power is removed, allow
seven seconds for this circuit to reset before re-applying the input voltage.
Connector (JP2)
DC jack, 5.5 mm O.D. x 2.5 mm I.D. Center Positive
Copyright © 2006, DYMO Corporation Page 13

USB Printer Interface
The LabelWriter 400 series printers all communicate with the host computer using a full-
speed USB 2.0 interface. This interface also operates with USB Version 1.1 or later. The
printers implement the standard USB Printer Class Device interface for communications
(see http://www.usb.org/developers/devclass/).
The LabelWriter Duo printer is implemented as a Composite USB interface. As such, it
will enumerate twice, as two different printers: once for the label printing portion and
once for the tape printing portion.
While it is not the purpose of this section to define how to write a USB driver for a
printer device, this section provides some product specific information that is required for
any USB device.
Each USB device provides plug-and-play information when it is connected to a host
computer. This information includes a manufacturer specific, or Vendor, ID (VID) and a
product specific ID (PID). These identifiers, when combined with the class type provided
during USB enumeration, are sufficient to identify the driver to load.
USB Vendor ID
The USB Vendor ID (VID) assigned to DYMO by the USB Implementers Forum is
0x0922h (2338 Decimal).
USB Product IDs
Each printer has a unique Product ID, as shown in the table below.
Printer Model Product ID (Hex)
DYMO LabelWriter DUO-962 0x0017
DYMO LabelWriter Twin Turbo 0x0018
DYMO LabelWriter 400 0x0019
DYMO LabelWriter 400 Turbo 0x001A
DYMO LabelWriter Duo - 12810x001D
2The DYMO LabelWriter Duo printer initially shipped with a 96-dot print head for the tape-printing
mechanism. This has been replaced with a 128-dot print head. Thus, there are two different Product IDs for
these two printer versions.
LabelWriter 400 Series Technical Reference Manual Page 14

Printer Commands
All LabelWriter 400 series printers implement the same basic commands. The
LabelWriter Twin Turbo printer implements one additional command, the Roll Selection
command, and the LabelWriter Duo printer implements an additional, but similar, set of
commands that are specific to printing on continuous-length tapes (see Appendix B).
Commands Sent to the Printer
The commands implemented by the LabelWriter printer are as follows. Note that each
command is listed with its mnemonic (<esc> B) as well as its hexadecimal representation
(1B 42). Parameter values are specified as "n" for single byte values or "n1 n2" for two
byte values.
<esc> B n Set Dot Tab
lB 42 ? n = starting byte number per line (binary), where:
0 <= n <= 83
default value = 0
This command shifts the starting dot position on the print head towards the right,
effectively introducing an increased left margin. Each byte represents 8 dots, so a value
of four for n would shift an image over 32 dots, or 32/300ths of an inch.
<esc> D n Set Bytes per Line
lB 44 ? n = number bytes per line, where:
1 <= n <= 84
default value = 84
This command reduces the number of bytes sent for each line if the right side of the label
is to be left blank.
Copyright © 2006, DYMO Corporation Page 15

<esc> L nl n2 Set Label Length
lB 4C ? ? nl, n2 = number of dot lines from sense hole to sense hole (binary), where:
nl = msb (binary)
n2 = lsb (binary)
default value = 3058 (10.2")
This command indicates the maximum distance the printer should travel while searching
for the top-of-form hole or mark. Print lines and lines fed both count towards this total so
that a value related to the length of the label to be printed can be used.
For normal labels with top-of-form marks, the actual distance fed is adjusted once the
top–of-form mark is detected. As a result this command is usually set to a value slightly
longer than the true label length to ensure that the top-of-form mark is reached before
feeding is terminated.
This command can also be used to put the printer into continuous feed mode. Any
negative value (0x8000 - 0xFFFF) will place the printer in continuous feed mode.
In continuous feed mode the printer will respond to Form Feed (<esc> E) and Short Form
Feed (<esc> G) commands by feeding a few lines out from the current print position. An
ESC E command causes the print position to feed to the tear bar and an ESC G causes it
to feed far enough so that a reverse feed will not cause lines to overlap.
<esc> E Form Feed
lB 45
This command advances the most recently printed label to a position where it can be torn
off. This positioning places the next label beyond the starting print position. Therefore, a
reverse-feed will be automatically invoked when printing on the next label. To optimize
print speed and eliminate this reverse feeding when printing multiple labels, use the Short
Form Feed command (see below) between labels, and the Form Feed command after the
last label.
<esc> G Short Form Feed
1B 47
This command feeds the next label into print position. The most recently printed label
will still be partially inside the printer and cannot be torn off. This command is meant to
be used only between labels on a multiple label print job.
<esc> q n Select Roll (Twin Turbo printer Only)
1B 71 ? n specifies the roll to print on, where:
30 (ASCII ‘0’) = Automatic selection
31 (ASCII ‘1’) = Left roll
32 (ASCII ‘2’) = Right roll
LabelWriter 400 Series Technical Reference Manual Page 16

This command specifies the roll on which the printer output should be imaged. In
Automatic Selection mode, the printer assumes that both rolls have the same media, and
it will toggle back and forth as rolls become empty.
<esc> A Get Printer Status
Returns a single byte with the following bit meanings (1 = true).
Bit Meaning
0 Ready (paper in, no jam)
1 Top of form
2 Not used
3 Not used
4 Not used
5 No paper
6 Paper jam
7 Printer error (jam, invalid sequence, and so on)
Note that printer ready is returned as 03h (Ready and Top of form).
<esc> @ Reset Printer
lB 40
This command resets all parameters (Dot Tabs, Line Tabs, Bytes per Line, and so on) to
their default values and sets top-of-form as true.
Note: This command is acted upon immediately; any data still in the print buffer will be
lost.
<esc> * Restore Default Settings
lB 2A
This command resets all internal parameters to their default values.
Note: This command is acted upon when it is received.
<esc> f 1 n Skip "n" Lines
1B 66 1 ? n = the number of lines to skip
This command skips over the next “n” lines on the label.
Copyright © 2006, DYMO Corporation Page 17

Note: This command is unusual because it requires the “1” prior to the value for the
number of lines to skip.
<esc> V Return Revision Letter/Number
1B 56
This command returns the printer model and firmware version number as an ASCII
string. The information is returned as an 8-character ASCII string in the following
format.
Bytes 0-4: the 5-digit model number (e.g. “93089”)
Byte 5: a lowercase letter (commonly “v”)
Bytes 6-7: the two-digit firmware version (e.g. “0N”)
Example: 98039v0K
<syn> nl..nx Transfer Print Data
16 ? ? Where:
nl = first 8 data bits
nx = last 8 data bits
This command sends a raster line of print data to the printer. For further details, see
“Print Data” on page 8.
<etb> nl..nx Transfer Compressed Print Data
17 ? ? Where:
nl = first compressed data byte
nx = last compressed data byte
This command sends compressed raster line images. This command is generally not
needed due to the high bandwidth of USB communications, but it might provide some
nominal increase in performance.
<esc> h Text Speed Mode
This command instructs the printer to print in Text Quality mode. This is the default, high
speed printing mode.
<esc> i Barcode and Graphics Mode
This command instructs the printer to print in Barcode and Graphics mode. This results in
lower speed but greater positional and sizing accuracy of the print elements.
<esc> c Set Print Density Light
This command sets the strobe time of the printer to 75% of its standard duty cycle.
LabelWriter 400 Series Technical Reference Manual Page 18

<esc> d Set Print Density Medium
This command sets the strobe time of the printer to 87.5% of its standard duty cycle.
<esc> e Set Print Density Normal
This command sets the strobe time of the printer to 100% of its standard duty cycle.
<esc> g Set Print Density Dark
This command sets the strobe time of the printer to 112.5% of its standard duty cycle.
<esc> y Set print resolution to 300x300
This command sets the step resolution of the printer to match its print element resolution,
giving 300 x 300 dpi printing.
<esc> z Set print resolution to 203x300
This command changes the step resolution of the printer to 203 dpi giving a printing
resolution of 203 x 300 dpi.
Copyright © 2006, DYMO Corporation Page 19

LabelWriter 400 Series Technical Reference Manual Page 20