Film Transport - Canon EOS 7 Service Manual

Part 2: Technical Information
1.5 F T
ILM RANSPORT
(1) Overview
As shown in Fig. 2-16, the film
transport system consists of the
main motor (M1) and secondary
motor (M2). By running forward
or in reverse, the respective
motor executes the operations
listed in Table 12.
Figure 2-19 shows a time chart
of how the M1 motor's running
direction (forward or reverse) drive
a series of operations such as the reflex mirror
up/down movement, shutter cocking, and film
advance. The M1 motor's driving power is
relayed to the film advance mechanism. The
film advance mechanism's two-speed (High
and Low) gear ratio and film rewind mode are
selected by the drive transmission mechanism
relayed by M2. With the EOS Elan II/Elan II
E/50/50 E/55, one motor drives everything.
With the EOS ELAN 7 E / EOS 30, the M2
motor switches the driving so that the M1
motor does not need to do it. As a result, the
film advance speed is faster and the film
transport is quieter.
Also, as mentioned above, the EOS ELAN 7 E
/ EOS 30's film advance mechanism has a two-speed (High and Low) gear. By
making the High gear's gear ratio small, the film advance time is greatly shortened.
Also, in low temperatures and other conditions which exhaust the batteries faster,
the mechanism switches from High gear to Low gear automatically to ensure that the
film transport can be driven.
The M1 and M2 motors and almost all the driver units are concentrated in the grip
portion of the camera. This makes the driving more efficient and the camera more
compact (the distance between the optical axis and grip is almost the same as the
EOS 300/Rebel 2000/EOS Kiss III's).
Film rewind fork
DX-code contacts
Fig. 2-16 Cross Section at Center
Motor Direction
Forward
M1
(ø12.5-L31mm) Reverse
M2 Reverse
(ø10✕8-L15mm) Forward
Table 2-5 Functions of the Motors
[EOS ELAN 7 E / EOS 30]
M1
Forward
coreless
motor Reverse
M2
Reverse
coreless
Forward
motor
[EOS ELAN II E / EOS 50 E]
Forward
Coreless
motor
Reverse
Fig. 2-15 Drive System Configuration
M2
M1
Guide roller 2
Guide roller 1
Pressure plate
2-12
Function
Film advance (High or Low)
Film rewind
Mirror movement
Shutter cocking
Control cam phase switching
Flash pop-up
Planetary gear Film advance High
switchover
Film advance Low
Film rewind
Planetary gear
switchover
Camera film
transport
Mirror driving
Control cam
Shutter cocking
Flash (transmission)
Front panel unit
Flash (driving)
Control cam Mirror driving, Shutter cocking
Flash
Planetary gear
switchover
Film advance
Film rewind