Canon BJ-W9000, Service Manual

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2.6 Excessive Temperature Protection Control of the BJ Print Head
This printer provides an excessive temperature protection control function, which
detects unusually high temperature states of the BJ print head(s).
This high temperature state occurs, for example, when the printing process continues
for some time with no ink supplied to the print head. The excessive temperature
protection control function prevents a nozzle failing to jet ink or other problems
encountered when the BJ print head gets too hot.
The excessive temperature protection control process will start once an extremely high
temperature has been detected by any one of the head temperature sensors, which are
built in each of the 12 nozzle arrays within the four BJ print heads. The excessive
temperature protection control provides the following three-level protective action:
Protection level 1:
If a high temperature exceeding the predefined lowest threshold is detected, the
printer allows the carriage continue in the direction of its current traverse and then
stops it at the end of the track. Then the wait control is activated to dissipate the
heat until it returns to the normal ambient level. When the temperature has
returned to normal, the printing process is resumed.
Protection level 2:
If a high temperature exceeding the predefined middle threshold (higher than the
lowest) is detected, the printer stops the carriage at its home position when the
backward printing has been completed. At the home position the ink is sucked from
the overheated nozzle array in order to forcibly cool it. When the temperature goes
down to the predefined lowest threshold (protection level 1), the wait control is
activated to dissipate the heat naturally. Finally, when the temperature goes down to
a normal level, the printing process is resumed.
Protection level 3:
If a high temperature that exceeds the predefined highest threshold (higher than the
middle) is detected, the printer cancels the printing operation immediately,
the carriage moves to its home position and an error message appears on the
operation display. When five minutes have elapsed, and the temperature has
dropped to a level at which the user can replace the BJ print head safely, a message
will appear asking the user to replace the print head.
2.7 Pause between Pages
A printed page that has been delivered from the printer is retained on the delivery
(printout) tray to allow it to dry in the normal ambient environment. With this product,
the page is discharged from the printer with its printed side facing down. The printout
tray is designed to avoid ink blots resulting from contact with the bottom surface by
employing appropriate architecture and materials. However, some types of paper, which
require long ink drying periods, may produce ink blots or stains on the surface.
To eliminate the possibility of ink blots, this printer provides the Pause between Pages
capability to temporarily suspend the delivery of paper from the printer's slot and so
allow the ink to dry. The paper will be delivered at the end of the specified Wait time
period. The user can enter the Wait time through the operation panel. This capability is
useful for printing when using a printing paper that needs time to dry, for example
film-type printing sheets.
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Part 4: Technical Reference BJ-W9000