Camera with automatic film initialization responsive to film loading door sensor
First Claim
1. A method of initializing film loading in a camera in response to securement of a film loading door in a light tight position, the camera having a motor drive circuit comprising a resistor-capacitor time constant circuit, the method comprising:
- providing a switch in circuit with said time constant circuit, said switch having first and second contact positions;
placing said switch in said first contact position to enable said time constant circuit in response to securement of said door in a light tight position; and
placing said switch in said second contact position to discharge said capacitor in response to unsecurement of said door from said light tight position to allow removal and reloading of film in the camera;
whereby said time constant circuit is reset to an initial condition to allow operation of said motor drive circuit for a sufficient time determined by said time constant circuit to ensure advancing of said film to a first exposure frame position in response to securement of said door in a light tight position after loading of film into the camera.
1 Assignment
0 Petitions
Accused Products
Abstract
In a low cost camera, film initialization to a first exposure frame by a time constant controlled drive circuit in which the time constant circuit is reset by a door sensor switch as a consequence of unloading and/or loading of film in the camera. This ensures that newly loaded film will be automatically initialized to the first exposure position without requiring the camera user to remember to actuate a shutter release button multiple times to achieve proper initialization. A film advance sensor switch is further employed to prevent subsequent frame advance if film initialization is for any reason not properly achieved.
-
Citations
10 Claims
-
1. A method of initializing film loading in a camera in response to securement of a film loading door in a light tight position, the camera having a motor drive circuit comprising a resistor-capacitor time constant circuit, the method comprising:
-
providing a switch in circuit with said time constant circuit, said switch having first and second contact positions; placing said switch in said first contact position to enable said time constant circuit in response to securement of said door in a light tight position; and placing said switch in said second contact position to discharge said capacitor in response to unsecurement of said door from said light tight position to allow removal and reloading of film in the camera; whereby said time constant circuit is reset to an initial condition to allow operation of said motor drive circuit for a sufficient time determined by said time constant circuit to ensure advancing of said film to a first exposure frame position in response to securement of said door in a light tight position after loading of film into the camera. - View Dependent Claims (2, 3, 4, 5)
-
-
6. Film initialization apparatus for a motor drive camera, the camera having a film drive motor, a motor drive circuit and a film loading door adapted to be closed in a light tight position after loading of film into the camera, the apparatus comprising:
-
a timer circuit coupled to said motor drive circuit, said timer circuit including a resistor-capacitor time constant circuit; and a film loading door securement sensor switch in circuit with said time constant circuit, said door securement sensor switch having first and second contacts and being set to said first contact to complete said time constant circuit in response to securement of said door in a light tight position and to said second contact to discharge said capacitor in response to unsecurement of said film loading door from said light tight position; whereby said time constant circuit is reset by discharge of said capacitor to an initial condition to allow operation of said motor drive circuit for a sufficient time determined by said time constant circuit to ensure advancing of said film to an initial exposure position in response to securement of said film loading door in a light tight position after loading of film into the camera. - View Dependent Claims (7, 8, 9, 10)
-
Specification