Electronic flash camera having reduced cycle time

• US 4,887,118 A
• Filed: 12/27/1988
• Issued: 12/12/1989
• Est. Priority Date: 12/27/1988
• Status: Expired due to Term

• Current Assignee: Senshin Capital LLC (Intellectual Ventures LLC)
• Original Assignee: Polaroid Corporation (PLR IP Holdings LLC)
• Inventors: Gaewsky, John P.
• Primary Examiner(s): Perkey, W. B.
• Application Number:
  US07/289,780
• Time in Patent Office: 350 Days
• Field of Search: 354/412, 354/413, 354/418, 354/127.1, 354/127.11, 354/127.12, 354/145.1, 354/173.1, 354/173.11, 354/83
• US Class Current: 396/206
• CPC Class Codes: G03B 15/05 Combinations of cameras with electronic flash apparatus; Electronic flash units
• CPC Class Codes: G03B 17/52 of the Land type
• CPC Class Codes: G03B 2215/0503 Built-in units

Abstract

A self-developing camera system having an electronic flash, a film transport and processing system including a motor, and a battery for supplying electrical power to the electronic flash and to the motor. The camera system further includes a control system that connects the battery to the electronic flash for charging purposes and to the motor simultaneously during processing of an exposed film unit as long as the battery voltage does not go below a level that would interfere with the motor'"'"'s ability to properly drive the film transport system, thus reducing the overall camera cycle time.

Claims

1. A self-developing camera having a reduced exposure cycle time, comprising:

an electronic flash for providing artificial illumination during an exposure;

a battery for supplying electrical power to said camera;

means for sensing the magnitude of the voltage of said battery;

means including an electrical drive motor for transporting and processing an exposed film unit; and

control means responsive to said voltage sensing means for enabling said electronic flash to operate in a charging mode during the operation of said drive motor when the voltage sensed by said voltage sensing means is equal to or greater than some predetermined magnitude, and for precluding the operation of said electronic flash in said charging mode when said sensed voltage is less than said predetermined magnitude while simultaneously maintaining operation of said drive motor to thereby reduce the overall time required to complete an exposure cycle.

2. A self-developing camera as defined in claim 1 wherein said predetermined voltage magnitude is equal to the minimum voltage required by said drive motor to properly actuate said transport and processing means and thereby acceptably process an exposed film unit.

3. A self-developing camera as defined in claim 1 wherein said control means further includes means for varying the charge rate of said electronic flash in direct relation to the extent to which said sensed voltage exceeds said predetermined magnitude.

4. The self-developing camera as defined in claim 3 wherein said means for varying said electronic flash charging rate includes a voltage step-up transformer having a primary coil and a secondary coil with its secondary coil being electrically coupled to means for storing electrical energy transformed by said transformer that is subsequently employed to artificially illuminate a scene during an exposure interval, switch means for periodically coupling said battery to said transformer primary coil and means responsive to said sensed voltage for controlling the rate at which and the length of time during which said switch means couples said battery to said transformer primary coil.

5. The self-developing camera as defined in claim 4 wherein said switch means includes a transistor and said means for controlling the rate at which and the length of time during which said battery is coupled to said transformer primary coil includes means coupled to said transistor for generating a square wave signal for actuating said transistor between its battery coupling state and its battery uncoupling state in direct relation to the pulse width of said square wave signal whose pulse width varies in direct relation to the extent to which said sensed voltage exceeds said predetermined magnitude.

6. A self-developing camera as defined in claim 1 wherein said electronic flash forms an integral part of said photographic camera.

7. A method of reducing exposure cycle time in a photographic camera of the self-developing type having an electronic flash, a film unit for forming a photographic image, a transport and processing means for transporting an exposed film unit during film processing and a battery for supplying electrical power to the camera, comprising the steps of:

sensing the magnitude of the voltage of the electrical power supplied to the camera by the battery; and

enabling the electronic flash to operate in a charging mode while the transport and processing means is transporting an exposed film unit for film processing when the magnitude of said sensed voltage is equal to or greater than some predetermined magnitude and precluding the electronic flash from operating in the charging mode while simultaneously maintaining the operation of the transport and processing means when the sensed voltage is less than the predetermined magnitude to thereby reduce the overall time required to complete an exposure cycle.

8. The method of claim 7 wherein the transport and processing means includes a drive motor and the predetermined voltage magnitude above or below which said step of enabling or precluding the operation of the electronic flash in a charging mode is equal to the minimum voltage required by the drive motor to actuate the transport and processing means and thereby properly process an exposed film unit.

9. The method of claim 7 additionally including the step of varying the charge rate of the electronic flash in direct relation to the extent to which the sensed voltage exceeds the predetermined magnitude.