Magnetic recording and regenerating unit for photographic film and camera

A magnetic recording unit for photographic film, which records magnetic information in a magnetic recording layer on photographic film by switching a direction of recording current flowing through a coil of a magnetic head, said magnetic recording unit comprising:

• two switching transistors connected to terminals of said coil;
• a port for transmitting a switching signal to said two transistors;
• and
• wherein after recording of the last magnetic information, a switching signal is input to said port so as to turn on said two switching transistors, and said ends of said coil of said magnetic head are short-circuited via said two switching transistors.

A magnetic record regenerating unit comprising:

• a magnetic head for accessing to a magnetic recording layer coated on photographic film during recording and regenerating, said magnetic head including a coil wound around a core;
• a recording circuit for supplying recording current to said coil during recording, and an amplification circuit for amplifying signal voltage generated at ends of said coil during regenerating and thereby outputting an regenerated signal, said recording circuit and said amplification circuit being connected to the ends of said coil in parallel;
• a power source circuit for supplying drive power to said amplification circuit and supplying reference voltage to said amplification circuit, said power source circuit including a power source;
• and
• wherein said recording circuit has a bridge circuit which consists of first and second switching transistors connected to said power source in parallel, third and fourth switching transistors respectively connected in series to said first and second switching transistors, and a magnetic head coil whose ends are connected to a point of contact between said first and third switching transistors and a point of contact between said second and fourth switching transistors, said recording circuit recording magnetic information in said magnetic recording layer by switching a combination of said first and fourth switching transistors and a combination of said second and third switching transistors so as to switch a direction of the recording current flowing through said coil;
• a base terminal of said first switching transistor connects to said power source circuit via a pull-up resistance, said power source circuit applying voltage to said base terminal during recording and regenerating;
• and
• during regenerating, said power source circuit applies the reference voltage to said point of contact between said second and fourth switching transistors.

A magnetic recording and regenerating unit for photographic film, which has film feed means for feeding photographic film coated with a magnetic recording layer with a motor and has a magnetic recording function of recording magnetic information in said magnetic recording layer while said photographic film is feeding and a magnetic regenerating function of reading magnetic information recorded in said magnetic recording layer, said magnetic recording and regenerating unit comprising:

• a magnetic head for accessing to the magnetic recording layer while the photographic film is feeding, said magnetic head including a coil wound around a core;
• a recording circuit for supplying recording current to said coil during recording, and an amplification circuit for amplifying signal voltage generated at ends of said coil during regenerating and thereby outputting an regenerated signal, said recording circuit and said amplification circuit being connected to the ends of said coil in parallel;
• reference voltage apply means for applying reference voltage to said amplification circuit only during regenerating, said reference voltage apply means cutting off the reference voltage from said amplification circuit during a period except for regenerating;
• driving power supply means for supplying driving power to said amplification circuit during regenerating and recording;
• and
• wherein during recording, said amplification circuit functions as a comparator to protect said amplification circuit from input of signal voltage during recording.

A camera which determines whether a film cartridge loaded in said camera is a partial cartridge, containing photographic film having an exposed frame and an unexposed frame, or not, and feeds the photographic film from the loaded film cartridge up to a first unexposed frame if determining that the loaded film cartridge is the partial cartridge;

• said camera comprising:
• first battery checking means consisting of first determination means for determining whether voltage of a battery in said camera is more than a first threshold level, and first prohibiting means for prohibiting photographing if the loaded film cartridge is not determined as being the partial cartridge and said first determination means determines that the voltage of said battery is less than the first threshold level;
• and
• second battery checking means consisting of second determination means for determining whether the voltage of said battery is more than a second threshold level higher than the first threshold level, and second prohibiting means for prohibiting photographing if the loaded film cartridge is determined as being the partial cartridge and said second determination means determines that the voltage of said battery is less than the second threshold level.

A camera which determines whether a film cartridge loaded in said camera is a partial cartridge, containing photographic film having an exposed frame and an unexposed frame, or not, and feeds the photographic film from the loaded film cartridge up to a first unexposed frame if determining that the loaded film cartridge is the partial cartridge;

• said camera comprising:
• temperature measuring means for measuring temperature within said camera;
• determination means for determining whether the temperature within the camera measured by said temperature measuring means is less than a predetermined reference temperature effecting a speed at which the photographic film is feeding;
• and
• prohibiting means for prohibiting photographing using the loaded film cartridge if said determination means determines that the temperature within said camera is less than the predetermined reference temperature and the loaded film cartridge is determined as being the partial cartridge.

A camera which determines whether a film cartridge loaded in said camera is a partial cartridge, containing photographic film having an exposed frame and an unexposed frame, or not, and feeds the photographic film from the loaded film cartridge up to a first unexposed frame if determining that the loaded film cartridge is the partial cartridge;

• said camera comprising:
• cartridge type detecting means for detecting a type of the loaded film cartridge;
• determination means for determining whether the loaded film cartridge contains reversal film or not, according to the type of the loaded film cartridge detected by said cartridge type detecting means;
• and
• prohibiting means for prohibiting photographing using the loaded film cartridge if said determination means determines that the loaded film cartridge contains the reversal film and the loaded film cartridge is determined as being the partial cartridge.

A camera which determines whether a film cartridge loaded in said camera is a partial cartridge, containing photographic film having an exposed frame and an unexposed frame, or not, and feeds the photographic film from the loaded film cartridge up to a first unexposed frame if determining that the loaded film cartridge is the partial cartridge;

• said camera comprising:
• speed measuring means for measuring speed at which the photographic film is feeding;
• determination means for determining whether the film feed speed measured by said speed measuring means is less than a predetermined reference speed;
• and
• prohibiting means for prohibiting photographing using the loaded film cartridge if said determination means determines that the film feed speed measured by said speed measuring means is less than the predetermined reference speed and the loaded film cartridge is determined as being the partial cartridge.

A camera which determines whether a film cartridge loaded in said camera is a partial cartridge, containing photographic film having an exposed frame and an unexposed frame, or not, and feeds the photographic film from the loaded film cartridge up to a first unexposed frame if determining that the loaded film cartridge is the partial cartridge;

• said camera comprising more than two of following four determination means:
• first determination means for measuring temperature within said camera and making a first determination that the measured temperature is less than a predetermined reference temperature effecting a speed at which the photographic film is feeding;
• second determination means for detecting a type of the loaded film cartridge and making a second determination that the loaded film cartridge contains reversal film;
• third determination means for measuring the film feed speed and making a third determination that the measured film feed speed is less than a predetermined reference speed;
• fourth determination means for making a fourth determination that voltage of a battery in said camera is lower than a predetermined reference voltage while said photographic film is feeding or current of a motor which feeds the photographic film is higher than a predetermined referenced current;
• and
• wherein said camera further comprises prohibiting means for prohibiting photographing using the loaded film cartridge if at least two of said four determinations are made by said determination means and the loaded film cartridge is determined as being the partial cartridge.

A magnetic regenerating unit for a camera, which feeds photographic film coated with a magnetic recording layer and regenerates magnetic information from said magnetic recording layer on said photographic film;

• said magnetic regenerating unit for the camera comprising:
• a magnetic head for accessing to the magnetic recording layer while the photographic film is feeding, said magnetic head including a coil wound around a core, a number of turns of said coil being determined so as to output a regenerated waveform which does not enable reading of said magnetic information but permits determination of whether any magnetic information is recorded or not;
• and
• determination means for determining whether any magnetic information is recorded or not in a magnetic record area for each frame on said photographic film based on voltage signals generated at ends of said coil.

A camera which loads therein a film cartridge containing photographic film coated with a magnetic recording layer, has film feed means for feeding the photographic film from the loaded film cartridge with a motor, determines whether the loaded film cartridge is a partial cartridge, containing a photographic film having an exposed frame and an unexposed frame, or not, and feeds the photographic film from the loaded film cartridge up to a first unexposed frame if determining that the loaded film cartridge is the partial cartridge;

• said camera comprising:
• magnetic recording means for recording magnetic information in a magnetic record area on the magnetic recording layer corresponding to an exposed frame during one-frame feeding in every photographing;
• and
• unexposed frame detecting means for detecting the first unexposed frame according to whether magnetic information is recorded in a magnetic record area for each frame on the photographic film, said unexposed frame detecting means comprising
• a magnetic head for accessing to the magnetic recording layer while the photographic film is feeding, said magnetic head including a coil wound around a core, a number of turns of said coil being determined so as to output a regenerated waveform which does not enable reading of said magnetic information but permits determination of whether any magnetic information is recorded or not;
• and
• determination means for determining whether any magnetic information is recorded or not in a magnetic record area for each frame on said photographic film based on voltage signals generated at ends of said coil.

A camera which loads therein a film cartridge containing photographic film coated with a magnetic recording layer, has film feed means for feeding the photographic film from the loaded film cartridge with a motor, determines whether the loaded film cartridge is a partial cartridge, containing a photographic film having an exposed frame and an unexposed frame, or not, and feeds the photographic film from the loaded film cartridge up to a first unexposed frame if determining that the loaded film cartridge is the partial cartridge;

• said camera comprising:
• magnetic recording means for recording magnetic information in a magnetic record area on the magnetic recording layer corresponding to an exposed frame during one-frame feeding in every photographing;
• and
• unexposed frame detecting means for detecting the first unexposed frame according to whether magnetic information is recorded in a magnetic record area for each frame on the photographic film, said unexposed frame detecting means comprising
• a magnetic head for accessing to the magnetic recording layer while the photographic film is feeding, said magnetic head including a coil wound around a core;
• an amplification circuit for amplifying signal voltage generated between terminals of said coil;
• a peak hold circuit for maintaining a maximum or minimum value of signals output from said amplification circuit;
• and
• determination means for determining whether any magnetic information is recorded or not in a magnetic record area for each frame on said photographic film according to comparison between a value representing voltage level of the signal maintained by said peak hold circuit and a reference value.

A magnetic regenerating unit for photographic film coated with a magnetic recording layer on which a magnetic record area for recording information for each frame is specified, said magnetic regenerating unit regenerating magnetic information from the magnetic record area while the photographic film is feeding;

• said magnetic regenerating unit for the camera;
• comprising:
• a magnetic head for accessing to the magnetic recording layer while the photographic film is feeding;
• and
• wherein said magnetic regenerating unit obtains a reference value from a voltage level of a regenerated signal representing an amplitude of signal voltage output from said magnetic head during regeneration of an area with no magnetic information located between magnetic record areas for two frames adjacent to one another on said photographic film;
• and
• said magnetic regenerating unit determines whether any magnetic information is recorded or not in a magnetic record area of each frame based on comparison between a value corresponding to an amplitude of signal voltage output from said magnetic head during regeneration of the magnetic record area of each frame and said reference value.

A magnetic regenerating unit for photographic film coated with a magnetic recording layer on which a magnetic record area for recording information for each frame is specified, said magnetic regenerating unit regenerating magnetic information from the magnetic record area while the photographic film is feeding;

• said magnetic regenerating unit for the camera;
• comprising:
• a magnetic head for accessing to the magnetic recording layer while the photographic film is feeding;
• and
• wherein said magnetic regenerating unit obtains a reference value from voltage level of a regenerated signal representing an amplitude of signal voltage output from said magnetic head during regenerating on an area with no magnetic information located in front of a magnetic record area corresponding to a first frame on the photographic film;
• said magnetic regenerating unit determines whether any magnetic information is recorded or not in a magnetic record area of each frame based on comparison between a value corresponding to an amplitude of signal voltage output from said magnetic head during regeneration of the magnetic record area of each frame and said reference value.