The pickup, feed, and delivery system consists of various rollers that the product motors drive. The product uses Tray 1 (the manual feeding tray) and a cassette in Tray 2 as media sources. The printed media is delivered to either the rear output bin (straight-through printing) or the top output bin (the default destination). A number of 500-sheet feeders and one 1,500-sheet feeder can be added to certain models. These accessories are discussed later in this chapter. The Tray 1 paper sensor (on the Tray 1 pickup assembly; PS105) detects media in Tray 1. The Tray 2 paper sensor (PS101) detects media in Tray 2. The paper-size switch (SW102) detects the media size that is loaded in Tray 2.
Two motors, a clutch, and a solenoid that are controlled by the DC controller PCA drive all of the rollers in the product.
The pre-feed, top-of-page, and fuser-assembly delivery sensors (PS102, PS103, PS700) detect media arriving and passing along the paper path. If the media does not reach or pass these sensors within a specific amount of time, the microprocessor on the DC controller PCA halts the product functions and a jam error message appears on the control-panel display.
Figure 5-24 Pickup, feed, and delivery system
The pickup-and-feed system is divided into two blocks: The pickup-and-feed block and the fuser/delivery block.
Figure 5-25 Pickup, feed, and delivery blocks
Pickup-and-feed block
The following functions take place in the pickup-and-feed block:
• Detection of media
• Detection of media-size
• Detection of media entering the paper path from Tray 1 or Tray 2
• Lifting of the Tray 2 paper plate
• Prevention of multiple-feeds
• Correction of page skew
When it receives a print command from the host computer, the DC controller PCA turns on the feed motor (M101) power. The motor drives the Tray 2 pickup, feed, and separation rollers. The drum motor power also turns on. The laser/ scanner motor power turns on.
The DC controller PCA then activates the feed clutch (CL101) to rotate the feed roller. The Tray 2 pickup solenoid is activated (SL101) and the pickup arm descends. The pickup roller touches the media and a sheet is fed into the product. The separation roller prevents multiple sheets of media from being fed at one time.
As the pre-feed sensor (PS102) detects the media, the dc controller PCA turns off the clutch, which stops the media. When the DC controller PCA detects that the laser/scanner is ready it activates the feed clutch again. The feed roller moves the media farther into the product. The registration shutter corrects page skew and the media is transported to the fuser/delivery block.
Fuser/delivery block
The fuser/delivery block consists of rollers, sensors, the fuser, and the output delivery assembly. The rollers transport the media through the fuser/delivery block paper path. The fuser applies heat and pressure to the media to permanently bond the toner image to the media. The output delivery assembly sends the printed media either to the rear output bin (if the rear output door is open) or to the top output bin (the default output delivery bin). Sensors along the paper path detect media movement, jams, and the top output-bin capacity.
Paper trays
Printing from Tray 1
The Tray 1 paper sensor (PS105) detects the presence of media in Tray 1. When the DC controller PCA receives the print command, the product starts the initial rotation phase, which consists of feed motor warm-up, scanner motor warm-up, high-voltage control sequence, and fuser warm-up. When the initial rotation phase ends, the Tray 1 pickup solenoid (SL102) is activated.
The cam rotates, the paper-tray lifter rises, and the media comes in contact with the Tray 1 pickup roller. At the same time, the Tray 1 pickup roller rotates twice and picks up a sheet of media from Tray 1. The separation pad prevents additional sheets from feeding with the first sheet.
The sheet then reaches the registration assembly, where its skew is corrected. The sheet then passes through the transfer, separation, and fusing stages; through the delivery unit; and is to the output bin.
IT NOTE: If media is removed from Tray 1 after the initial rotation phase, but before the pickup roller pulls the media from the tray, the Tray 1 pickup roller might continue to rotate up to six times, after which a jam detected.
Printing from Tray 2
When the DC controller PCA receives the print command, the feed motor (M101) and scanner motor start their rotation. When the feed motor reaches its prescribed speed, the feed roller clutch (CL101) and Tray 2 pickup solenoid (SL101) are activated. (The feed motor rotation drives the Tray 2 pickup roller, Tray 2 feed roller, Tray 2 separation roller, and paper-feed rollers.)
The Tray 2 pickup roller, which the pickup solenoid activates, rotates once and picks up the media in the tray. The separation roller prevents additional sheets from feeding with the first sheet, and the media is fed to the pre-feed sensor (PS102).
The sheet then reaches the registration assembly, where its skew is corrected. The sheet then passes through the transfer, separation, and fusing stages; through the delivery unit; and to the output bin.
Formatter system The formatter is involved in the following procedures.
• Controlling the Sleep mode
• Receiving and processing print data from the various product inputs
Monitoring control-panel functions and relaying product status information (through the control panel and the bidirectional input/output)
• Developing and coordinating data placement and timing with the DC controller PCA
Storing font information
• Communicating with the host computer through the bidirectional interface
The formatter receives a print job from the bidirectional interface and separates it into image information and instructions that control the printing process. The dc controller PCA synchronizes the image-formation system with the paper-input and -output systems, and then signals the formatter to send the print-image data.
The formatter also provides the electrical interface and mounting locations for an EIO card, additional memory DIMMs, and the hard-disk accessory.
Sleep mode
period of time. When the product is in Sleep mode, the control-panel backlight is turned off, but the product retains all product settings, downloaded fonts, and macros. The default setting is SLEEP MODE=ON, with a 30-minute idle time. Sleep mode also can be turned off from the RESETS menu on the control panel.
The product exits Sleep mode and enters the warm-up cycle when any of the following occurs.
• A print job, valid data, or a PML or PJL command is received at the serial port or EIO card.
• A control panel key is pressed.
The top cover is opened.
• A tray is opened.
The engine-test button is pressed.
& NOTE: Error messages override the Sleep message. The product enters Sleep mode at the
appropriate time, but the error message continues to appear.
Resolution Enhancement technology
The formatter contains circuitry for Resolution Enhancement technology (REt), which modifies the standard video dot data on its way to the dc controller PCA to produce "smoothed" line edges. The REt can be turned on or off from the control panel or from some software programs. The default setting is medium.
If NOTE: The REt settings that are sent from software programs or printer drivers override the control-panel settings.
EconoMode
The EconoMode setting uses up to 50% less toner than standard mode printing by reducing the dot density. However, EconoMode does not extend the life of print-cartridge components. EconoMode, which can be thought of as "draft mode," can be selected from the control panel (PRINT QUALITY menu) and through some software programs and printer drivers. The default setting is OFF.
A CAUTION: HP does not recommend full-time use of EconoMode. If EconoMode is used full-time, it is possible that the toner supply will outlast the mechanical parts in the print cartridge.
i? NOTE: EconoMode does not affect print speed or memory usage, or extend the life of the print cartridge.
Input/output
The following sections discuss the input and output features of the product.
USB
The product includes a universal serial bus (USB) 2.0 connection.
Embedded print server
For all models except the HP LaserJet 4014 base model, the product includes an HP Jetdirect embedded print server for connecting to a 10/100Base-TX network.
Expanded I/O
An optional expanded I/O (EIO) card can be installed in the designated slot on the formatter. It provides automatic I/O switching between multiple computers or networks that are connected to the product.
Hard-disk accessory
The optional hard-disk accessory can be mounted in one of the EIO slots on the rear of the formatter. The optional ElO-based hard disk is used for creating multiple original prints (mopies) and storing forms, fonts, and signatures.
CPU
The product formatter incorporates a 400 MHz RISC processor.
Product memory
If the product encounters a problem when managing available memory, a clearable warning message appears on the control panel.
Some product messages are affected by the auto-continue and clearable warning settings on the control-panel SYSTEM SETUP menu. If CLEARABLE WARNING=JOB is set on the control panel, warning messages appear on the control panel until the end of the job from which they were generated. If CLEARABLE WARNING=ON is set, warning messages appear on the control panel until OK is pressed. If an error occurs that prevents printing and AUTO CONTINUE=ON is set, the product goes offline for 10 seconds before it returns online. If AUTO CONTINUE=OFF is set, the message appears until OK is pressed.
Read-only memory
Besides storing microprocessor control programs, the read-only memory (ROM) stores dot patterns of internal character sets (fonts).
Random-access memory
The random-access memory (RAM) contains the page, I/O buffers, and the font storage area. It stores printing and font information received from the host system, and can also serve to temporarily store a full page of print-image data before the data is sent to the print engine. Memory capacity can be increased by adding DIMMs to the formatter. Note that adding memory (DIMMs) might also increase the print speed for complex graphics.
DIMM slot
The DIMM slot can be used to add product memory.
Nonvolatile memory
The product uses nonvolatile memory (NVRAM) to store I/O and information about the print environment configuration. The contents of NVRAM are retained when the product is turned off or disconnected.
Memory Enhancement technology
The HP Memory Enhancement technology (MEt) effectively doubles the standard memory through a variety of font- and data-compression methods.
If NOTE: The MEt is available only in PCL mode; it is not functional when printing in PS mode.
PJL overview
Printer job language (PJL) is an integral part of configuration, in addition to the standard printer command language (PCL). With standard cabling, use PJL to perform a variety of functions.
• Two-way communication with the host computer through a bidirectional parallel connection. The
product can send the host computer information about such things as the control panel settings,
and the control panel settings can be changed from the host through two-way communication.
• Dynamic I/O switching. The product can be configured with a host on each I/O by using dynamic
I/O switching. Even when the product is offline, it can receive data from more than one I/O
simultaneously, until the I/O buffer is full.
• Context-sensitive switching. The product can automatically recognize the personality (PS or PCL)
of each job and configure itself in that personality.
• Isolation of print environment settings from one print job to the next. For example, if a print job is
sent to the product in landscape mode, the subsequent print jobs are printed in landscape mode
only if they are formatted for it.
PML
The printer management language (PML) allows remote configuration and status monitoring through the I/O ports.
Control panel
The formatter sends and receives product status and command data to and from a control-panel PC
