Home > HP > Printer > HP Laserjet 5 Service Manual

HP Laserjet 5 Service Manual

    Download as PDF Print this page Share this page

    Have a look at the manual HP Laserjet 5 Service Manual online for free. It’s possible to download the document as PDF or print. UserManuals.tech offer 1114 HP manuals and user’s guides for free. Share the user manual or guide on Facebook, Twitter or Google+.

    							EconoMode
    The EconoMode setting uses approximately 50% less toner than standard mode
    printing by reducing the dot density. However, EconoMode does not extend toner
    cartridge component life. EconoMode, which can also be thought of as “draft
    mode,” is user-selectable through some software applications. The default setting is
    Off.
    EconoMode vs Normal Mode
    NoteEconoMode does not affect print speed or memory usage.
    Memory Enhancement technology (MEt)
    The Hewlett-Packard Memory Enhancement technology (Met) effectively doubles
    the standard memory through a variety of font and data compression methods. MEt
    is only available in PCL mode and is not customer selectable. When using the
    host-based driver, your PC handles memory management.
    Figure 5-3
    5 - 10 Functional Overview 
    						
    							Enhanced I/O
    The Enhanced I/O feature allows printer memory to be used for storing data
    received from the host computer. When Enhanced I/O is enabled, you can send
    more data to your printer in shorter amounts of time, which allows you to return to
    your application sooner. Enhanced I/O has the following options:
    ·Auto—allows the printer to use Enhanced I/O memory allocation to increase the
    speed of data transfer from the host computer to the printer, if necessary.
    ·Off—uses the minimum amount of printer memory for storing data sent from the
    host computer.
    Enhanced I/O is only available in PCL mode. When using the host-based driver,
    your PC handles memory management.
    Page Protect
    Page complexity (rules, complex graphics, or dense text) may exceed the printer’s
    ability to create the page image fast enough to keep pace with the Image Formation
    process. If Page Protect is disabled and a page is too complex, the page may print in
    parts (for example, the top half on one page and the bottom half on the next page).
    Some print data loss is likely in these instances, and the printer will display an error
    message.
    Page Protect allows the Formatter to create the entire page image in page buffer
    memory before physically moving the paper through the printer. This process
    ensures that the entire page will be printed. Page Protect applies only to PCL
    printing. The default setting is Auto.
    PJL Overview
    Printer Job Language (PJL) is an integral part of configuration, in addition to the
    standard Printer Command Language (PCL). With standard Centronics cabling, PJL
    allows the printer to perform functions such as:
    ·Two-way communicationwith the host computer through a Bi-directional Parallel
    connection. The printer can tell the host such things as the control panel status.
    ·Isolation of print environment settingsfrom one print job to the next. For
    example, if a print job is sent to the printer in landscape mode, the subsequent print
    jobs print in landscape only if they are formatted for landscape printing.
    5
    Functional
    Overview
    Functional Overview 5 - 11 
    						
    							Image Formation System
    Laser printing requires the interaction of several different technologies (such as
    electronics, optics, and electrophotographics) to provide a printed page. Each
    process functions independently and must be coordinated with the other printer
    processes. Image formation consists of six processes:
    ·Step 1. Drum Cleaning
    ·Step 2. Drum Conditioning
    ·Step 3. Image Writing
    ·Step 4. Image Developing
    ·Step 5. Image Transferring
    ·Step 6. Image Fusing
    Image Formation Block Diagram
    2. Scanning Exposure
    1. Primary Charging
    7. Drum Cleaning3. Developing
    5. Separation
    4. TransferRegistration
    6. Fusing Paper Delivery
    Manual Feeding Slot
    Multi-Purpose Tray
    Drum Cleaning
    Block
    Fuser Block
    Transfer Block Electrostatic Latent Image Formation Block
    Developing
    Block Flow Of Paper
    Direction Of Drum Rotation
    Figure 5-4
    5 - 12 Functional Overview 
    						
    							Toner Cartridge
    As the “heart” of the Image Formation System, the toner cartridge houses the
    cleaning, conditioning, and developing steps of the process. The toner cartridge
    contains the photosensitive drum, primary charging roller, developing station, toner
    cavity, and cleaning station. Including these components, which wear, degrade, or
    are consumed in the replaceable toner cartridge, eliminates the need for a service
    call when replacement is required. The special photosensitive properties of the drum
    allow an image to be formed on the drum surface and then transferred to paper.
    CAUTIONThe printer’s toner cartridge does not include a light-blocking shutter. Be careful to
    avoid exposing the drum to light, which can permanently damage the drum. Protect
    the cartridge whenever removing it from the printer.
    Step 1: Drum Cleaning
    The cleaning blade is in contact with the surface of the drum at all times. As the
    drum rotates during printing, excess toner wiped off and stored in the waste toner
    receptacle.
    Step 2: Drum Conditioning
    After the drum is physically cleaned, it must be conditioned. This process consists
    of applying a uniform negative charge on the surface of the drum with the primary
    charging roller, located in the toner cartridge. The primary charging roller is coated
    with conductive rubber. An AC bias is applied to the roller to erase any residual
    charges from any previous image. In addition, a negative DC bias is applied by the
    charging roller to create a uniform negative potential on the drum surface. The
    amount of DC voltage is modified by the print density setting.
    Step 3: Image Writing
    During the writing process, a modulated laser diode projects the beam onto a
    rotating scanning mirror. As the mirror rotates, the beam reflects off the mirror, first
    through a set of focusing lenses, off a mirror, and finally through a slot in the top of
    the toner cartridge, and onto the photosensitive drum. The beam sweeps the drum
    from left to right, discharging the negative potential wherever the beam strikes the
    surface. This creates a latent electrostatic image, which later is developed into a
    visible image.
    Because the beam is sweeping the entire length of the drum and the drum is
    rotating, the entire surface area of the drum can be covered. At the end of each
    sweep, the beam strikes the beam detect lens, generating the Beam Detect Signal
    (BD). The BD signal is sent to the DC Controller, where it is converted to an
    electrical signal used to synchronize the output of the next scan line of data.
    5
    Functional
    Overview
    Functional Overview 5 - 13 
    						
    							Step 4: Image Developing
    At this stage of the process, the latent electrostatic image is present on the drum.
    The toner particles obtain a negative surface charge by rubbing against the
    developing cylinder which is connected to a negative DC supply. The negatively
    charged toner is attracted to the discharged (exposed, grounded) areas of the drum,
    and repelled from the negatively charged (non-exposed) areas.
    Step 5: Image Transferring
    During the transferring process, the toner image on the drum surface is transferred
    to the paper. A positive charge applied to the back of the paper by the transfer roller
    causes the negatively charged toner on the drum surface to be attracted to the paper.
    After separation, the drum is cleaned and conditioned for the next image.
    Step 6: Image Fusing
    During the fusing process, the toner is fused into the paper by heat and pressure to
    produce a permanent image. The paper passes between a heated fusing element and
    a soft pressure roller. This melts the toner and presses it into the paper.
    5 - 14 Functional Overview 
    						
    							Paper Feed System
    Both the Paper Input Bin and the Single Sheet Input Slot merge into one, main input
    area. Paper placed in either of these areas enables the Paper Out Sensor (sensor
    202), which informs the DC Controller that paper is present.
    When the printer receives a print job and is ready to print, the DC Controller
    enables the Laser/Scanner Assembly and the Motor. Paper motion begins when the
    DC Controller energizes solenoid SL1. This causes the paper pick up roller to rotate
    once. Two actions occur as a result of this rotation. First, the paper kick plate pushes
    the paper against the pick-up roller. Second, the pick-up roller grabs the top sheet
    and advances it to the Feed Assembly drive rollers. To ensure that only one sheet is
    fed, a main separation pad, along with two subpads, hold the remainder of the stack
    in place.
    The feed assembly drive rollers advance the paper to the Paper Registration
    photosensor (PS203). This sensor informs the DC Controller of the exact location of
    the paper’s leading edge, so that the image being written on the photosensitive drum
    can be precisely positioned on the page. The feed assembly drive rollers then
    advance the paper to the transfer area where the toner image on the photosensitive
    drum is transferred to paper.
    After the image is transferred, the paper enters the fusing assembly where heat from
    the fuser and pressure from the Pressure Roller permanently bond the toner image
    to paper. The Paper Exit Sensor (PS201) determines that paper has successfully
    moved out of the fusing area. The fusing assembly exit rollers deliver paper to
    either the Output Paper Bin or the Front Output slot, depending upon the position of
    the Face-up/Face-down lever.
    5
    Functional
    Overview
    Functional Overview 5 - 15 
    						
    							Figure 5-5 shows a simplified paper path and the locations of the photosensors and
    rollers.
    Simplified Paper Path
    Figure 5-5
    5 - 16 Functional Overview 
    						
    							Figure 5-6 shows the locations of the photosensors, switches, solenoid, and other
    important printer elements. Table 5-1 describes the function of each photosensor
    and the solenoid.
    Solenoid and Sensors
    Figure 5-6
    No. Name Description
    SL1 Paper Pick-up Solenoid Enables the Paper Pickup Roller.
    PS201 Paper Exit Sensor Senses when paper has successfully moved out of the
    fusing area and the next sheet of paper can be fed.
    PS202 Paper Out Sensor Senses no paper in either the Paper Input Bin or Manual
    Input Slot. If this sensor does not sense paper in the Input
    Paper Bin or the Single-Sheet Input Slot, the formatter
    displays the paper-out indication on the front panel. Paper
    must be reloaded before printing can resume.
    PS203 Paper Registration Sensor Detects the leading and trailing edges of the paper.
    Synchronizes the photosensitive drum and the top of the
    paper.
    PS204 Door Open/Cartridge Sensor (HP LaserJet 5L only)
    In the HP LaserJet 6L, SW101 performs the
    functions of 5L’s PS204.Detects whether printer door is open and cartridge is in
    place. If the door is open or the cartridge is not in place, the
    control panel LEDs will display an error message. Printing
    cannot continue until the door is closed and the cartridge is
    in proper position.
    Table 5-1Solenoid and Photosensors
    5
    Functional
    Overview
    Functional Overview 5 - 17 
    						
    							Paper Jam Detection
    The Paper Out Sensor (PS202), Paper Registration Sensor (PS203), and the Paper
    Exit Sensor (PS201) detect when paper is moving through the printer. (See Figure
    5-5 for roller and sensor locations.) If a paper jam is detected, the DC Controller
    immediately stops the printing process and causes a paper jam indication on the
    front panel.
    A paper jam can be detected under any of the following conditions:
    ·Power-On Jams.Paper is present under either PS201 or PS203 at power-on.
    ·Pickup Jams. Paper does not reach and clear photosensor PS203 within a specified
    period of time. The time period begins when the Paper Pickup Solenoid (SL1) is
    energized.
    ·Delay Jams. Paper does not reach or clear a specific photosensor within a specified
    period of time.
    5 - 18 Functional Overview 
    						
    							Basic Sequence of Operation
    The Formatter PCA and the DC Controller PCA share information during printer
    operation. The DC Controller-to-Formatter Connector (J201) forms a link which
    operates as a serial data bus. This allows printer status, command information, and
    dot-image data to be passed between the two PCAs. Figure 5-7 shows the general
    timing of the printer events. The following events take place during normal printer
    operation:
    Period Timing Purpose
    WAIT From when the paper is inserted to the end of Main
    Motor initial rotation.Clear the drum surface potential and clean the
    Transfer Roller.
    STBY (standby) From the end of the WAIT or the LSTR period until
    the input of the PRNT signal from the Formatter. Or
    from the end of the LSTR period until power OFF.Maintain the printer in ready state.
    INTR (initial
    rotation)From the input of the PRNT signal from the
    Formatter until the laser diode intensity has been
    stabilized.Stabilize the photosensitive drum sensitivity in
    preparation for printing. Also clean the Transfer
    Roller.
    PRNT From the end of initial rotation until the Scanner
    Motor stops.Form images on the photosensitive drum based on
    the /VDO signal from the Formatter and transfer the
    image to paper.
    LSTR (last
    rotation)From the primary voltage (DC) OFF until the Main
    Motor stops.
    If another PRNT signal is sent from the Formatter,
    the printer returns to the INTR period. If not, it
    returns to the STBY period.Deliver the last sheet of paper. Also clean the
    Transfer Roller.
    Refer to Timing Diagram on the next page Table 5-2
    Printer Timing
    5
    Functional
    Overview
    Functional Overview 5 - 19 
    						
    All HP manuals Comments (0)

    Related Manuals for HP Laserjet 5 Service Manual