Canon iPF780 Series Service Manual page 233

Chapter 7
15) HEAD CHK
Perform in case the printhead is abnormal. It can guess whether the failure cause is the printhead or not.
MEMO:
As the printhead and thermistor are high temperature after printing immediately, perform this mode after 5 minutes or more printing is completed.
Display the value (analogue) detected by the printhead, the thermistor on the carriage PCB, DI sensor (Di0/Di1) and head Vh.
Check whether the detection value is normal or not to judge the abnormal part.
Press the / key to select the item, and then press the
- temp
- AD Di0
- AD Di1
- AD Vh
<CHECK>
Judge the failure part by comparing the temperature of the printhead and the value detected by thermistor on the carriage PCB.
*: Adequate temperature ranges when the surrounding temperature (temperature/humidity sensor detection value) of the printer is 25 degrees centigrade. For ex-
ample, when the surrounding temperature is 30 degrees centigrade, above temperatures rise each 5 degrees centigrade.
e) REPLACE
1) CUTTER
This mode is for replacing the cutter.
f) COUNTER
Displays the life (operation frequency and time) of each unit, print counts for each media type, and else.
The count values can be printed from [PRINT INF].
7-20
key to display the detection value.
2 5 1 2 6
- 1 5 2 5
Printhead temperature
(centigrade degrees)
chipA chipB
chipD chipE
2 5 5
1 0 2 3
Head DI sensor (Di0) detection analogue value
2 5 5
1 0 2 3
Head DI sensor (Di1) detection analogue value
1 0 2 3
Head VH detection analogue value
PrintHead temperature Thermistor temperature
(Centigrade degree)* (Centigrade degree)*
22 to 28 22 to 28
21 or less, 29 or more
21 or less, 29 or more 22 to 28
21 or less, 29 or more
- 2 7 T 3 0
1 2 7 t 2 8
T: Thermistor detection temperature
mounted on the Carriage PCB
chipC
(centigrade degrees)
chipF
t: Temperature/Humidity detection sensor
detection temperature
(centigrade degrees)
F-7-23
1 2 7 1 0 2 3
6 3 1 2 7
F-7-24
1 2 7 1 0 2 3
6 3 1 2 7
F-7-25
F-7-26
T-7-1
Normal
The part except for the printhead may have a failure.
(Carriage PCB, flexible cable, main controller PCB)
The printhead may have a failure.
The printhead or the carriage PCB or the flexible cable
or the main controller PCB may have a failure.
D
0
D
1
V
h
Judgement