Pickup-and-feed-system
The pickup and feed system consists of several types of feed rollers and sensors.
The DC controller drives the system by controlling the feed motor (M4), ETB motor (M5), and four drum motors (M6, M7, M8, M9) and the solenoids for the trays. In models that include an automatic duplex accessory, the duplexing feed motor (M10) and reversing motor (M11) are also part of the system.
NOTE: Tray 2 must be installed in order to print from tray 1 or tray 3.
DC controller PCA
PCA
Fuser
Fuser
Fuser
PCA
ENWW
Figure 4-5 Pickup-and-feed system
Pickup-and-feed-system 55
Sensors in the pickup-and-feed system trays (cassettes)
Paper sensors detect media in the trays. Other sensors react to the media as it moves through the paper path. If the media does not reach or pass each sensor within a specified time period, the DC controller determines that a jam has occurred and alerts the formatter. In models that include an automatic duplex accessory, the paper path contains additional sensors that detect movement through the duplex path.
Figure 4-6 Pickup-and-feed system sensors
SR705
SR706
SR707
SR708
Fuser pressure-release sensor
Output-bin-full sensor
Multipurpose-tray paper sensor
Multipurpose-tray paper-position sensor (HP Color LaserJet 3000, 3800, and CP3505 Series printers only)
56 Chapter 4 Theory of operation ENWW
SR709
SR710
SR714
SR6001
SR6005
SW2
Cassette paper-presence sensor
Top-of-page sensor
One-sided paper sensor
Paper-loop sensor
Fuser paper delivery sensor
Cassette-presence switch
Cassette pickup mechanism
When the cassette is correctly installed, SW2 detects its presence. The cassette paper sensor
(SR709) detects whether media is present in the cassette, and the cassette media sensor detects the type of media. When the cassette is correctly installed and the correct media type is present, the cassette pickup operation begins.
1.
The DC controller receives a print command from the formatter, and then begins rotating the pickup-and-feed motor (M4) at the correct speed for the media type.
2.
After the motor reaches the correct speed and the fuser is at the correct temperature, the cassette pickup solenoid (SL5012) turns on and the cassette pickup roller begins rotating.
3.
The cassette lifting plate lifts the paper stack, and the cassette pickup roller picks up one sheet of media. The separation pad prevents multi-feeds.
ENWW
Figure 4-7 Cassette pickup mechanism
Pickup-and-feed-system 57
Multipurpose-tray pickup mechanism
The cassette must be installed in order for the multipurpose (MP) tray to operate. The MP tray paper sensor (SR707) detects whether media is present in the MP tray. When the cassette is correctly installed and media is present, the MP tray pickup operation begins.
1.
The DC controller receives a print command from the formatter, and then begins rotating the pickup-and-feed motor (M4) at the correct speed for the media type.
2.
After the motor reaches the correct speed and the fuser is at the correct temperature, the MP pickup solenoid (SL5013) turns on and the MP pickup roller begins rotating.
3.
The MP pickup roller picks up one sheet of media. The separation pad prevents multi-feeds.
4.
When the media reaches SR708, motor M4 stops, the MP tray media sensor detects the media, and then motor M4 restarts and resumes feeding media into the printer.
Figure 4-8 Multipurpose-tray pickup mechanism
Feed-speed control
To optimize print quality, the pickup-and-feed motor rotates at different speeds depending on the type of media.
NOTE: In the following table, normal speed is 22 ppm for the HP CLJ 3800 and CP3505 models, and normal speed is 18 ppm for the HP CLJ 3600 models. Normal speed is 30 ppm for the HP CLJ 3000 model (black mode only).
58 Chapter 4 Theory of operation ENWW
Media type
Plain
Rough
Thin
Thick
Thicker
Postcard
Thicker postcard
Glossy
Heavy Glossy
Extra Heavy glossy
Envelope
Label
Gloss film
Transparency
HP CLJ 3800 and
CP3505
22 ppm
17.6 to 18 ppm
22 ppm
17.6 to 18 ppm
17.6 to 18 ppm
17.6 to 18 ppm
11 ppm
17.6 to 18 ppm
11 ppm
8.8 to 9 ppm
17.6 to 18 ppm
17.6 to 18 ppm
3.6 ppm
3.6 ppm
HP CLJ 3600
17.6 to 18 ppm
17.6 to 18 ppm
17.6 to 18 ppm
17.6 to 18 ppm
17.6 to 18 ppm
17.6 to 18 ppm
11 ppm
17.6 to 18 ppm
11 ppm
8.8 to 9 ppm
17.6 to 18 ppm
17.6 to 18 ppm
3.6 ppm
3.6 ppm
HP CLJ 3000 (fullcolor mode)
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
HP CLJ 3000
(monochrome mode)
30 ppm
15 ppm
30 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
15 ppm
ENWW Pickup-and-feed-system 59
Sensor jam detection
1
4
2
3
1.
Cartridge sensor assembly
2.
Paper and registration sensor covers
3.
Cassette media sensor (HP Color LaserJet 3600, 3800, CP3505 only)
4.
Temperature sensor
5.
Media-sensor assembly (500-sheet feeder)
60 Chapter 4 Theory of operation ENWW
ENWW
The following jams can occur during operation:
● Pick-up delay jam. The printer makes three attempts to pick up media from a tray. When the topof-page sensor (SR710) does not detect the leading edge of a page within a specific time after the third attempt, the printing operation stops. The time varies depending on the printer model and the media source, as follows.
HP CLJ 3000: 1.3 seconds from the cassette; 2.2 seconds from the multipurpose tray (tray 1);
2.3 seconds from the paper feeder
HP CLJ 3600: for black printing, 1.0, 1.5, or 1.6 seconds; for color printing, 1.7, 2.7, or 2.9
seconds
HP CLJ 3800 and CP3505: 1.3 seconds from the cassette; 2.2 seconds from the multipurpose tray (tray 1); 2.3 seconds from the paper feeder
● Pick-up stationary jam. The printing operation stops when the top-of-page sensor (SR710) does not detect the trailing edge of a page within a specific time after it has detected the leading edge.
HP CLJ 3000: approximately 3.2 seconds
HP CLJ 3600: for black printing in Normal mode, 2.3 seconds; for color printing in Normal mode,
4.6 seconds
HP CLJ 3800 and CP3505: approximately 4.0 seconds
● Delivery delay jam. The printing operation stops when the fuser paper delivery sensor (SR6005) does not detect the leading edge of a page within a specific time after it has detected the leading edge.
HP CLJ 3000: approximately 3.0 seconds (in Normal print mode)
HP CLJ 3600: for black printing in Normal mode, 2.2 seconds; for color printing in Normal mode,
3.8 seconds
HP CLJ 3800 and CP3505: approximately 3.8 seconds (in Normal print mode)
● Wrapping jam. The printing operation stops when the fuser paper delivery sensor (SR6005) does not detect any media within a specific time. The time varies depending on the length of the media that the top-of-page sensor (SR710) detected.
HP CLJ 3000: approximately 1.9 seconds (in Normal print mode with letter-size media)
HP CLJ 3600: for black printing in Normal mode with letter-size media, 1.3 seconds; for color printing in Normal mode with letter-size media, 2.4 seconds
HP CLJ 3800 and CP3505: approximately 2.4 seconds (in Normal print mode with letter-size media)
● Delivery stationary jam. The printing operation stops when the fuser paper delivery sensor
(SR6005) continues to detect paper for a specific time after the top-of-page sensor (SR710) detected its presence.
HP CLJ 3000: approximately 3.1 seconds (in Normal print mode)
HP CLJ 3600: for black printing in Normal mode, 2.2 seconds; for color printing, 3.9 seconds
HP CLJ 3800 and CP3505: approximately 3.9 seconds (in Normal print mode)
Pickup-and-feed-system 61
● Duplexing pickup delay jam (for models that include an automatic duplex accessory). The printing operation stops when the top-of-page sensor (SR710) does not detect the leading edge of the second side of the paper within a specific time after the duplexing feed motor (M10) started rotating.
HP CLJ 3000: approximately 2.0 seconds (in Normal print mode)
HP CLJ 3600: for black printing in Normal mode, 1.4 seconds; for color printing, 2.5 seconds
HP CLJ 3800 and CP3505: approximately 2.5 seconds (in Normal print mode)
● Residual-paper jam. The printing operation stops when any of the following sensors detects media during the initial sequence period:
Top-of-page sensor (SR710)
Paper-loop sensor (SR6001)
Fuser paper delivery sensor (SR6005)
Duplexing reverse sensor (SR823)
Multipurpose tray (MPT) paper-position sensor (SR708)
● Door-open jam. The printing operation stops when the DC controller detects that a printer door is open.
62 Chapter 4 Theory of operation ENWW
