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10

Functional Overview

HP DesignJet 430, 450C and 455CA Printers

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Introduction
The HP DesignJets 430, 450C and 455CA follow on from and replace the DesignJet 330 and 350C. The HP DesignJets 430, 450C and 455CA (like the DesignJets 230, 330, 250C and 350C) have inherited much of the system architecture and features of the DesignJet 220. Their writing system, however, is based on that of the DesignJet 650C. This chapter describes some of the main features of the HP DesignJets 430, 450C and 455CA. Before reading it, read the functional overview of the DesignJet 220 ' HP DesignJet 220 and HP DesignJet 200 Printers - Service Manual," part number C3187 90000. (Information on the DesignJet 650C ' HP C2858B/C2859B DesignJet 650C Service Manual," part number C2858 90000 Rev B).

Roll Media
When a roll feed assembly is installed on the Printer, roll media can be used. The roll feed assembly consists of: Two roll feed components. D A spindle. D Two media stops.
D

The roll feed assembly is installed below the sheet media entry path, to allow the ease of loading for sheet media. When roll media is loaded into the Printer, it is passed around a diverter roll, which optimizes the infeed path to the Printer. Once a plot/print is completed, a built in cutter automatically slides across the paper to cut the plot/print from the roll.

Removing Static Charge from the Media
An anti static brush located under the entry platen prevents static charge from building up on the media. A charge can cause the media to stick to itself and jam the Printer.

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HP DesignJet 430, 450C and 455CA Printers

Functional Overview

Gripping the Media
When you load the media, it is gripped by the pinch arms. Pinch Arm Sensor The pinch arm sensor is a switch sensor that is attached to the Printer Chassis. It detects the position of the pinch arm lever. Linkage, attaching the lever to a cam, causes the cam to release the switch as the pinch arms are raised. The pinch arm sensor is electrically connected to the main PCA.

Providing a Force on Top of the Media
Bail The bail provides a normal force on top of the media. There is no bail sensor on the Printer to detect if the bail is up or down. Bail Lift Mechanism The bail features an automatic lift mechanism driven by the media motor using a series of gears and actuated by the cartridge carriage. The cable based design eliminates the torque on the axle of the bail lift cam and thus improves reliability. This mechanism is also more accessible. (Removal ' page 8 28.)

Detecting the Lines and Media Edges
Line Sensor The line sensor on the cartridge carriage is used to: Detect the left and right media edges. D Detect and measure lines drawn on media when performing accuracy calibration. D Scan the setup and alignment sheets. D Find the platen roller reference mark.
D

Functional Overview

HP DesignJet 430, 450C and 455CA Printers

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Moving the Carriage
Carriage Drive Mechanics Motor, Belt and Pulley D The carriage (Y axis) drive consists of a DC motor directly driving a single belt and the carriage. D The motor assembly itself provides the tension needed on the belt, eliminating the need for a separate pulley tensioner. D The belt clamps itself to the carriage; there are no separate belt clamps. D The interface between the motor shaft and belt is friction based. D You can remove the belt without having to remove the pulley on the left end of the belt. Carriage Guidance The carriage moves along on just one stainless steel slider rod. It is guided by two integrated bronze bushings, which are self lubricating, and a back wheel. Positional Feedback An encoder strip provides feedback on the position of the carriage. The strip does not require adjustment.

Carriage PCA
The carriage PCA is based on that of the DesignJet 650C. It connects to the main PCA through a long 60 conductor (2x30) trailing cable. The carriage PCA contains: Optical line sensor D Thermistor circuit D Linear encoder D Cartridge nozzle firing circuit
D

Some electronic components on the DesignJet 450C and 450CA carriage PCA are not present on the DesignJet 430 carriage PCA. At power on the Printer firmware identifies whether the carriage is for a color or a monochrome model, and behaves accordingly.

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HP DesignJet 430, 450C and 455CA Printers

Functional Overview

Providing Ink
Print Cartridges The HP DesignJets 430, 450C and 455CA use the same cartridges as does the HP DesignJets 330 and 350C. Distance between Carriage and Media The distance between the carriage and the writing surface can determine image sharpness. As the distance increases, the drop shape and directionality degrade and are more difficult to predict. You can change the distance using the adjusting screw on the carriage (details ' page 5 5).

Carriage (Side View)
Adjusting Screw Back Slider

Beam Crossşsection

Producing an Image
Print Mode Characteristics Note that the firmware can recognize from the plot data whether a plot is color or monochrome. You do not set this parameter on the front panel.

Functional Overview

HP DesignJet 430, 450C and 455CA Printers

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Bail-Lift Engaging Tab Integrated Line Sensor

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Servicing the Cartridges
Service Station D The service station is easy to access and remove, and is replaceable as one unit. D The absence of a drop detector implies a different cartridge maintenance algorithm to guarantee correct nozzle conditions. The Printer warms the nozzles and spits ink: Before each plot. D After each cartridge change. D While printing, depending on: cartridge, humidity, temperature, and plot ink density.
D D

The ventilation holes, which were located on the service station sled on the DesignJet 650C, are now located on the ink separator to prevent them from becoming clogged.

Spittoon A single, redesigned spittoon is located on the right side of the Printer. Primer The Printers feature a manual primer, based on that of the DeskJet 1200, instead of the automatic one of the DesignJet 650C. A bellows assembly provides a vacuum to suck ink from the nozzles. The suction tubes have a wider diameter than those of the DesignJet 650C, to help prevent clogging. D An ink separator isolates the bellows from the cartridges, preventing ink contamination of the bellows.
D

Although the primers for the DesignJets 430, 450C and 455CA and DesignJets 230 and 250C look identical, their characteristics are different. Installing the incorrect primer can damage the cartridges or reduce the servicing of the cartridges. For the correct part numbers for the primers ' chapter 7.

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HP DesignJet 430, 450C and 455CA Printers

Functional Overview

Electronics Module
The electronics module includes the main PCA, power supply and fan. It is one exchangeable part; you do not need to open it. If you replace the electronics module, remember to swap any SIMMs from the old module to the new one. Sensors There is no bail sensor for the HP DesignJets 430, 450C and 455CA. There is a pinch arm sensor which is different to the one installed on the HP DesignJets 330 and 350C. The following sensors connect to the main PCA: The cover sensor is a mechanical switch that detects if the Printer cover has been raised. If you open the cover while the Printer is plotting, the plot is cancelled! D The media sensor detects the presence of media. It is also used to determine media length. D The line sensor sends signals to the carriage and is used to detect the mark encoder and read alignment patterns. It is also used to determine media width. D The pinch arm sensor detects whether the pinch arms have been raised. The servo processor uses the sensor to determine the pinch arm position during the initialization sequence.
D

ROM The Printer firmware code is contained on either an in built masked ROM (soldered to the main PCA) or a flash ROM SIMM (installed in the inner most socket at the back of the Printer). If both are present, the Printer recognizes the code on the ROM SIMM instead of that on the in built ROM. The power on LED sequence tells you whether the Printer is using code from in built ROM or from a ROM SIMM. If the LEDs begin to light up from the right, then the Printer is using the ROM SIMM. If the LEDs begin to light up from the left, then the Printer is using the built in ROM. To find out the firmware code revision level that the Printer is using, print a user setup sheet or a service configuration plot. RAM The Printers have a standard four megabytes of on board RAM. They also have one RAM expansion socket, which can hold an optional 4 , 8 , 16 or 32 megabyte DRAM SIMM. The socket is the outer most one at the back of the Printer.

Functional Overview

HP DesignJet 430, 450C and 455CA Printers

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EEROM EEROM is used as nonvolatile storage for calibration and configuration data. Useful information from the EEROM is printed on the service configuration plot. The EEROM is soldered to the Main PCA in both new and rebuilt electronic modules. If you clear the EEROM or replace the electronics module, perform all calibrations. Also note that the factory spittoon value on the cleared or new EEROM is 0%. Keep in mind that the value printed on the service configuration plot may greatly underestimate the amount of ink in the spittoon. Input/Output Interfaces The Printers have both a parallel (Bi Tronics) and a serial (RS 232 C) interface. Unlike the DesignJet 650C, they have no modular input/output (MIO). You can connect the Printers to a network by means of an HP JetDirect EX or HP JetDirect EX Plus3 external print server. Bi Tronics In addition to the operating modes of the DesignJet 220, the Bi Tronics interfaces feature the extended capability port (ECP) forward and reverse operating modes, providing for faster communication. RS 232 C The supported baudrates are 1200, 2400, 4800, 9600, 19200 and 38400, with eight bits and no parity, or seven bits with either odd or even parity. Mark parity is not supported. Both XON/XOFF and DTR handshaking are supported. ENQ/ACK handshake is not supported. Power Supply An auto ranging power supply is located in the electronics module.
WARNING
The primary side of the power supply contains rectified line voltage that can be lethal when touched even if the ON/OFF switch is OFF. In any case, you should not need to open the electronics module. It is one exchangeable part.

Water Condensation In humid environments, water may condense on the side plates. A wick attached to the underside of the right side plate routes water drops away from the main PCA electronics.

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HP DesignJet 430, 450C and 455CA Printers

Functional Overview

Memory Usage
It is difficult to calculate the amount of Printer memory needed to plot a drawing of any given file size. Memory is used, not just to hold the input data, but also for system overhead, processing work space, and storage of the internal representation of the plot. Some types of graphics require relatively large amounts of memory. Examples are wide lines, raster fill patterns, polygons, and user defined lines. Plot Orientation The output orientation of the drawing also has an impact on memory usage. Compare a plot of horizontal lines with one of vertical lines. Lines plotted parallel to the carriage axis take up considerably less memory than those plotted perpendicular to it. The Printer builds graphic display objects on a swath by swath basis. A horizontal line can be contained in one swath. A vertical line spans many swaths and therefore requires more entries in the Printer's internal display list. Raster Image Processor The raster transfer language (RTL) provides a solution to insufficient memory on the Printer. When all the data is sent to the Printer in the order left to right and top to bottom, the Printer is able to plot the data as it receives it. For this to happen, software (a raster image processor) in the computer must first rasterize all the data. The software issues a command (referred to in RTL as no negative motion) telling the Printer that it will not receive data for any media location on which it has already plotted. The use of no negative motion is called flow mode. Data flows through the Printer without being stored in a display list, so the size of the file that you can send is almost unlimited.

Functional Overview

HP DesignJet 430, 450C and 455CA Printers

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