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Designjet Spare Parts

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We have one of the largest parts stock in the UK for HP Designjet plotter spare parts, including end of line (EOL) parts which are no longer manufactured by HP.  


Designjet Spare Parts - Introduction

This area of our website has been designed to give you a more detailed overview about individual HP Designjet Spare Parts.  Not all descriptions are correct for all printers and not all printers utilise the same parts, nor do all of those parts look the same.  The parts overview below has been compiled to give you a general flavour about what your different Designjet parts do, and their approximate location in the printer.  The information and drawings below have been taken from a varied selection of Designjet manuals such as Designjet 5000, 1050, 500, 510, T790 and T2300, T2500 therefore if you are attempting work on a Designjet you may find various parts are not exactly as shown in the diagrams below


 Cutter Assembly


Set up Printheads


 Carriage Belt

The Cutter Assembly is designed to
trim the leading edge of a roll of paper
when loaded, and then again after every
print. The Carriage Assembly engages
it by travelling to the left hand side of
the printer and pulling the arm out on
the cutter.  This lowers the rotary blade
which allows the carriage to travel to the 
right and trim the paper.  The Cutter can
become blunt and although it forms part
of the Carriage, it can be replaced 
separately. The Cutter becomes blunt
over time with use and quickly blunts if 
the wrong type of media (such as thick 
canvas) is put through a machine not 
designed/compatible with such heavy
media weights.


In some models a Purge Tubes
function needs to be carried out, when
fitting new Tube Assemblies.  This allows
the tubes to be primed and the air
removed and replaced with ink. In order
to carry out this function, a set of setup
printheads will be required.  These
Printheads are not regular printheads
and cannot be used instead of regular 
printheads, which are different.  In order
to prime the tubes, the status of your
ink cartridges must not be showing as
Low or Very Low - so a new set of inks
need to be purchased if this is the case.
These are also known as Start up
Print heads. 


The carriage belt is attached to the
underside of the carriage assembly
and is driven by the Y axis motor on
one side and connected to pulley at
the other.  This is the most common
part to wear on a Designjet.  Belts differ
from one machine to the next e.g.
some belts are made up of two rubber
strips that are connected together by
metal fasteners.  Notably, they are
made ofblack rubber and have groove
patterns (vertical grooves to assist the
motor to pull, and horizontal grooves
to assist the pulley). The belt must be
placed with care in the correct

 HP Designjet Cutter Assembly - Diagram and schematic


 HP Designjet Setup Printheads (Start up Print Heads) - diagram and schematic


 HP Designjet Encoder Strip and Carriage belt - diagram and schematic


Service Station



Carriage Assembly



Power Supply Unit

The Service Station has a number of 
functions.  Primarily it caps the printheads
to prevent them drying out in between
printing.  It also uses wipers to remove
excess ink or dirt build up on the bottom
of the printheads, and with some models
has a spittoon attached as a way of
disposing of the excess ink.  Over time it
will fill up with ink and will need replacing.  
The Drop Detect Sensor is connected to
the Service Station (this monitors and
tests the state of the Printheads).


The Carriage Assembly (also known as
the Pen Carriage) holds the printheads.
The printheads are fed ink from the ink
cartridges via the Ink Tubes Assembly
and are responsible for releasing the ink
onto the paper through a series of small
nozzles.  The cutter is attached to the
Carriage Assembly to trim the media.
The Trailing Cable is also connected to
the Carriage Assembly which in turn is
connected to the Electronics module.


The Power Supply Unit (also known
as the PSU) connects to the electronics
module or main board and is located
in the rear electronics panel of the
Printer.  It converts the mains electricity
to voltages used on the Electronics
Module.  The PSU includes the power
switch and a failure typically presents
as the printer having no power or where
 the printer will start up but will be in
a continual start up loop cycle.

 HP Designjet Service Station - diagram and schematics    HP Designjet Carriage Assembly (Pen Carriage) - diagram and schematic    HP Designjet Power Supply Unit - diagram and schematic


Drive Roller Encoder Sensor



Drop Detect Sensor



Y Axis Motor

The Drive Roller Encoder Sensor reads
the Encoder Disk that is attached to the
media roller.  The Encoder Disk passes
through the sensor and the fine lines
around the outer edge of the disk are
read, so that the printer knows how 
far to rotate the media roller.


The Drop Detect Sensor is part of the
Serivce Station and it is responsible for
testing and monitoring the state of the
Printheads.  It does this by dropping 
small amounts of ink through the sensor
in order to sense if the Printhead is 
working properly.


The Y Axis motor (also known as the
Scan Axis motor) is used to drive the
Carriage assembly.  It does this by
having its cogs move the carriage belt,
which itself is attached to the underside
of the carriage assembly via a pulley. 

 HP Designjet Drive roller encoder sensor - diagram and schematic    HP Designjet Drop Detect and Service station - diagram and schematics    HP Designjet Y Axis (Scan Axis / Paper) Motor - diagram and schematic


Media/Paper Sensor



Ink Supply Station



Encoder Strip

The media sensor is located underneath
the platen assembly.  It has a small
flag that sits in the sensor at one end
(in turn the sensor has a cable that runs
to the interconnect PC board) while the
other end goes through the platen to
where the media is fed through. When
the media is fed through it moves the
flag out of the sensor - and this part
can get broken easily.  


In the Printer, the Ink Cartridges reside
inside the Ink Supply Station (ISS).  
The ISS is the part of the Printer that
provides the pressure to pump the ink
from the Ink Cartridges to the
Printheads. There are slots in the ISS
for each ink cartridge, with each cartridge
colour having its own place. The Ink
Tubes Assembly then connects into the
bottom of the ISS to connect up with the
Ink Cartridges.  


The Encoder Strip is a thin metal strip
that runs along the width of the printer
and has a number of fine vertical lines
printed on it which allows the carriage 
to assess its current position.  The
carriage assembly counts these lines
so it knows exactly where it is on the
scan axis.  It can usually be seen when
you open the top cover.

 HP Designjet Media Sensor (Paper Sensor) - diagram and schematic    HP Designjet Ink Supply Station (ISS) - diagram and schematics    HP Designjet Encoder Strip and Carriage belt - diagram and schematic


Ink Tubes Assembly



X Axis Motor



Front Panel

The Ink Tubes Assembly (also known
as RIDS) is assisted by an Air Pressure 
System (APS) which pumps ink from the 
Ink Cartridges (which are located in the 
ISS) through the Ink Tubes Assembly
and down to the Printheads (which are
located in the Carriage Assembly).  The 
printheads then place the ink onto the 
paper through small nozzles.  


The X Axis Motor (also known as the
Paper Motor or Media Motor) is located
underneath the platen.  It rotates the
media roller assembly, so that the
paper or media is in the correct position.
It knows how far to turn because of the
driver roller encoder.


The Front Panel controls the function of
the printer and can show ink levels,
status of printheads, print settings,
paper loaded, calibration tools, print
previews.  It also warns of any
issues or problems, and displays error
codes or messages.  Some front panels
are LCD, the oldest printers offer
a system of lights. 

 HP Designjet Ink Tubes Assembly (RIDS) - diagram and schematics    HP Designjet X Axis Motor (Paper Motor) - Diagram and schematic    HP Designjet Front Panel - Diagram and Schematic


Trailing Cable



Memory Card



Clutch Assembly

The Trailing Cable has two ribbon cables;
one which connects to the carriage
assembly while the other connects to
the electronics module. Failure to replace
the trailing cable properly may result in
blowing the main electronics board.


The Memory Card processes jobs and
most printers allow for additional
memory to be installed, in order
to speed up various print processes.  
Some printers will require a GL2 card
in order to install additional memory.


The Clutch Assembly is engaged by the
Carriage pressing against a lever to
engage it.  The Clutch then engages
the Lower Over Drive Rollers to move
the media backwards in order to find
the leading edge of the paper.  

 HP Designjet Trailing Cable - diagram and schematic    HP Designjet Memory / GL2 card - diagram and schematic    HP Designjet Clutch Assembly - diagram and schematic


Jet Direct Card






Star Wheel Assembly

The Jet Direct Card allows the printer
to be networked so that a number of
users can print to it.


The spindle is what the roll of paper
slots onto.  It has end caps either
side and usually the end caps only
get broken with users who drop the
roll of paper  onto the spindle rather
than "placing" it on.


The Star Wheel Assembly attaches
to the Bail Arm which runs across the
length of the print output area.  
The Star Wheels assist with
controlling the paper.

 HP Designjet Jetdirect Card - photo    HP Designjet Spindle / Spindle End Caps - diagram and schematic    HP Designjet Starwheel Assembly - diagram and Schematic


Interconnect PCA Board



Electronics Module


The interconnect PCA Board sits on top
of the Service Station holder on some
models, and connects to the electronics
module.  Typically it controls the Service
Station, Ink Supply Station, Pinch Lever
Sensor and Front Panel.


Also known as the main logic board, 
this is the brains of the HP Designjet
and/or main logic centre which controls
and manages data input and resulting
print output. This is one of the most
expensive components and is the part
which often gets damaged if there is
a power surge.

 HP Designjet Interconnect PCA Board - drawing and schematic   HP Designjet Electronics Module - Diagram and schematic