Panasonic FP-7742 / FP-7750 (serv.man2) Service Manual ▷ View online
1-13
Introduction
• There are normally no special problems with storage and transport in a cold
climate but, store in a low humidity condition. Do not put supplies near heaters.
5)
Safety and hygiene
Toner has the property of easily being wind blown. Toner on skin does not
cause any damage to health but, inhaling it is undesirable even if a powder is
simply dust. Therefore, be careful not to inhale toner .
• Handle the toner gently when changing cartridges, and developer when pouring
in the developer unit. If you have breathed in a lot of toner by mistake, rinse
out your mouth with water completely. Any toner on the skin should be washed
off with soapy water.
• Toner stuck on clothing must be removed in a dry condition (by a vacuum
cleaner, brush, or beating,) and then washed with soapy water. Wiping off with
benzine, alcohol, or thinner is not recommended because it may partially melt
the components of toner even more, resulting in a harder stain and spot.
• Toner spilled must be cleaned with a vacuum cleaner, and then wiped with a
cloth dampened with a neutral detergent and wrung out.
• If exposed to flames toner and developer will burn. Keep these supplies away
from open flames.
• Any wasted consumables (photo receptor, developer and toner) should be
recycled.
• Wear rubber gloves, eye protection and so on before handling any solvents
such as IPA.
New Function
2-1
Section II
New Function
2. 1 Image Control (Quantum
TM
Technology)
• Even if the toner density is at it's standard level, the copy image may vary with
time depending on the characteristics of drum and the environmental variations.
To prevent this change, the copy density sensor which is installed under the
developer unit controls the image to stablize the copy image.
• Controlling the image
During initialization after turning on the power, the copy density sensor reads the
white density, medium density (line pattern density patch) and black density
developed on the drum surface.These three values are compared with the ideal
gamma curve stored in the copiers memory.
The copier detects the amount offset from the standard gamma curve (such as "a
little background" or "light image") and calculates the variables for copy density
control in accordance with Quantum
TM
Technology. In this way it finds the optimum
compensation values to tighten the gamma curve for maintaining peak copy quality.
By means of this process, copy quality is stabilized by the various compensations
enabled by Quantum adjustment in image production.
• The control of the gamma curve stabilizes copy quality by monitoring three points
of copy quality (white density, medium density and black density) and has a direct
effection on background, solid area density and good reproduction of fine lines
regardless of environmental changes and variation with time and copy volume.
• Quantum
TM
Technology
Quantum
TM
Technology is adaptive control on the basis of quantative reasoning
theory. While successively reasoning and learning the change of process
characteristics regardless of environmental changes and the variations with time
and the number of copies on the copier, the system reads the patch marks and
determines the best values of exposure and surface potential to establish the
best gamma curve for optimum copy quality.
2-2
• Quantum
TM
Technology is applied at the following intervals.
a) During initialization after turning on the power.
b) After every 1,000 sheets following execution of Quantum
TM
Technology
(But, every 200 sheets following the execution of F8-09 for the next
500 sheets)
c) After turning on the power (up to 200 copies)
d) After replacing the toner bottle (up to 200 copies)
• Copy density detecting sensor
Two sensors for detection of copy density are used, one for white density, and
line pattern density and one for detection of black density. (Temperature and
humidity sensors are not used.)
• To correct for toner build up on the sensor, clean the sensor at the same time as
the replacement of the drum. The system provides a measured amount of light
and detects the reflected light. The resultant value is used for sensor compensation.
This becomes the reference value.
• As the reference value of the white density changes, various components are
adjusted according to characteristics of the gamma curve.
Reference
F5-25: Quantum Technology Operation ON/OFF
F mode
F6-80: Automatic compensation value (read only)
F6-81: Automatic compensation value (read only)
F6-82: Automatic compensation value (read only)
F6-28: White density reference value
(set by Quantum)
F6-29: Black density reference value
(set by Quantum)
New Function
2-3
Amount of carrier passing TDC sensor
Toner density condition Sensor output voltage
Less
High
Lower than normal
Much
Low
Higher than normal
<Control>
The following controls are necessary for normal control of toner density
1)
Automatic adjustment of TDC sensor gain (during execution of F8-C09)
(to attain the standard reference level).
2)
Maintain the standard level by control of toner density during use.
<Explanation of the control system>
1)
Automatic adjustment of TDC sensor gain
Automatically adjust the reference through the TDC sensor by executing service
mode F8-09.
The operation flow is as shown below.
2. 2 Toner Density Control
To keep toner density(toner carrier ratio) in the developer unit constant, the TDC
sensor (toner density sensor) which is installed under the developer unit detects the
amount of carrier in the developer unit to control the toner density.
<Fundamentals>
The change of magnetic flux density in accordance with the amount of carrier
(magnetic power) of the developer (mixture of toner and carrier) is detected by the
TDC sensor and is converted to a voltage to control the toner density.
<Change of toner density and change of TDC sensor output voltage>
F8-09 start
CPU will check toner density sensor output. (2.5 V)
CPU will adjust sensor gain
control signal
control signal
Memory number will be changed to new number in memory.
(F6-21 or F6-26)
(F6-21 or F6-26)
Toner density sensor output voltage will be adjusted to 2.5 V
Yes
No
Click on the first or last page to see other FP-7742 / FP-7750 (serv.man2) service manuals if exist.