Camera with information recording and film end detector

Abstract: A film end detecting device of a camera, used for a film in which film aligning perforations are regularly formed in units of frames, is disclosed. The device includes: a winding means for winding the film, which has an end detection perforation formed at an interval smaller than the predetermined interval on a film end side of the film aligning perforation of the last frame; a detection means for detecting the perforations of the film; control means for controlling the film feeding means to wind the film sufficiently to enable full recording of information magnetically on said film after the film end has been detected.

Description: BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a film end detecting device of a camera. Related Background Art Conventionally, a pre-wind type camera, which draws out an entire unexposed film from a loaded film cartridge, and rewinds it into the film cartridge in every photographing operation, is known. Also, a technique for recording various pieces of information on a magnetic recording medium coated on a film is already known (U.S. Patent No. 4,864,442). When pieces of information to be recorded on the magnetic recording medium are ones in units of photographing frames, if these pieces of information are not recorded at predetermined positions in units of photographing frames, recorded information may not often be reproduced in correspondence with the photographing frames. In the conventional pre-wind type camera, the first frame (a frame closest to the film end) is aligned while drawing out a film, and the second or subsequent frame is aligned while rewinding a film. For this reason, only the first frame is undesirably shifted from other frames. The present applicant proposed a film feed control device of a camera, which had an object to precisely align the first frame with a predetermined photographing position (Japanese Patent Application Laid-Open No. 2-173998). With this device, the number of photographable frames of a film are memorized or stored in advance in a camera, and perforations of the film are detected in a pre-wind operation to count the number of fed frames of the film. Then, whether or not all the photographable frames are drawn out is detected based on the count result and the stored number of frames. If it is detected that all the photographable frames are drawn out, the film is further drawn out by a predetermined amount. Thereafter, the film is rewound to align the first frame with the predetermined position. In this manner, the first frame can be precisely aligned. A pre-wind type camera or normal wind type camera for winding a film frame by frame in every photographing operation detects a state wherein a film is completely drawn out and can no longer be fed to determine a film end, and the camera stops a film feeding motor. However, in the device described in Japanese Patent Application Laid-Open No. 2-173998, the number of fed frames of a film is counted in a pre-wind operation, and whether or not all the photographable frames are drawn out is detected based on the count result and the stored number of photographable frames. For this reason, for example, if a battery is removed during the pre-wind operation, the count result disappears. Therefore, even if a new battery is loaded to continue the pre-wind operation, the first frame cannot be aligned with the predetermined position. As described above, in a camera, which determines a film end when a film is completely drawn out and can no longer be fed, the film is temporarily forcibly pulled although it can no longer be fed. As a result, the film may often be undesirably stretched or broken. It has been proposed to provide a device for detecting perforations of a film to detect a film end, and starting a film rewinding operation upon detection of the film end, in association with a photographing information recording device of a camera, which winds a film by one frame upon completion of a photographing operation of each frame, and records information in a magnetic recording region of a film upon the winding operation. Such an arrangement may use a technique for recording information (e.g., a photographing date) for each photographing frame on a magnetic recording region of a film by a magnetic head upon the film winding operation of each frame. In the above-mentioned device, however, the film rewinding operation is started as soon as the film end is detected, although the film end is detected during a period between the beginning of the winding operation of the last frame and a timing before completion of a magnetic recording operation for the last frame. For this reason, information cannot be completely recorded on the last frame. WO 90/04215 A1 discloses a camera having means for magnetically recording information in association with each photographed frame. SUMMARY OF THE INVENTION It would be beneficial to provide a camera which can perform film end detection free from problems. It would also be beneficial to provide a film end detecting device of a camera, which can perform film end detection before a film is completely drawn out to the film end. It would further be beneficial to provide a photographing information recording device of a camera, which can completely record information even for the last frame. Aspects of the invention are set out in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1 to 11 are views according to embodiments of the present invention, in which Fig. 1 is a diagram showing an arrangement of a device according to an embodiment of the present invention, Fig. 2 is a block diagram showing the arrangement of a photographing information recording device of a camera according to an embodiment of the present invention, Fig. 3 is a view showing the positional relationship among a photosensor, a magnetic head, and an aperture, Figs. 4A and 4B are views showing the positional relationship among photographing frames, perforations, and magnetic recording regions on a film, Fig. 5 is a flow chart showing a control sequence, Fig. 6 is a flow chart showing another embodiment, Fig. 7 is a view showing the positional relationship between a photosensor and a film according to still another embodiment, Fig. 8 is a flow chart showing a control sequence, Fig. 9 is a flow chart showing a control sequence for determining the last frame, Fig. 10 is a view showing a modification wherein a photosensor is arranged at another position, and Fig. 11 is a flow chart showing a control sequence. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a photographing information recording device according to the present invention will now be described. Fig. 1 illustrates the arrangement of an embodiment of the present invention. In the device of this arrangement, when the determination means 102 determines that the photographed frame is the last frame, the control means 103 controls the film feeding means 101 to wind the film by at least an amount capable of recording information for the last frame. Thus, even when the film end is detected during a period between the beginning of the winding operation of the last frame and a timing before completion of magnetic recording for the last frame, information can be completely recorded for the last frame. Fig. 2 is a block diagram showing an arrangement of a photographing information recording device of a camera according to an embodiment of the present invention. A photo-electric detection circuit 1 detects perforations of a film 10 (Figs. 4A and 4B) using a connected photosensor 1a such as a photoreflector. A recording and reproduction circuit 2 records information such as a photographing date on a film using a connected magnetic head 2a. A motor drive circuit 3 drives a connected film feeding motor 3a to perform a film feeding operation (winding or rewinding operation). The camera of this embodiment adopts a normal wind system for winding up a film frame by frame in every photographing operation. A half-depression switch SW1 is turned on in response to a half-depression operation of a release button (not shown). A full-depression switch SW2 is turned on in response to a full-depression operation (release operation) of the release button. A control circuit 4 comprises, e.g. a microcomputer. The control circuit 4 controls the motor drive circuit 3 and the recording and reproduction circuit 2 on the basis of signals from the switches SW1 and SW2, and the photo-electric detection circuit 1, as will be described later. Fig. 3 is a view showing the positional relationship among an aperture AP, the photosensor 1a, and the magnetic head 2a of the camera. Figs. 4A and 4B are views showing a portion of a 36-frame film used in this embodiment. In this film 10, in order to assure a sufficient storage capacity outside photographing frames, the number of perforations used for a film feeding operation is decreased, minimum necessary perforations are formed in correspondence with photographing frames, and a blank space is assigned to a storage area. More specifically, a blank space except for all the perforations below the frames is used for a storage area. In Fig. 4A, the 34th, 35th, and 36th photographing frames are indicated by F34, F35, and F36. In this film 10, magnetic recording regions Dn are formed in correspondence with the photographing frames Fn (n = 1 to 36), and two perforations Pna and Pnb are formed at precise positions for each photographing frame Fn. The perforation Pna (first perforation) is located at the trailing end side of the film with respect to the frame Fn, and the perforation Pnb (second perforation) is located at the leading end side of the next frame. An end detection perforation PA is formed next to the perforation P36b. When a kth photographing frame Fk is aligned with the aperture AP shown in Fig. 3, the photosensor 1a is located at a position where it detects the second perforation Pkb, and the magnetic head 2a opposes the leading end portion of the magnetic recording region Dk. An interval between the perforations P36b and PA is shorter than an interval between the perforations P(n-1)b and Pna (n = 1 to 36). Fig. 5 is a flow chart showing a control sequence executed by the control circuit 4. This program is started when a main switch (not shown) of the camera is turned on. In this case, assume that one of frames opposes the aperture AP, and the photosensor 1a can detect the second perforation Pnb of the frame. In step S201 in Fig. 5, the control waits until the half-depression switch SW1 is turned on. If it is determined that the half-depression switch SW1 is turned on, a photometry circuit and a ranging circuit (neither are shown) are started to perform photometry and ranging operations in step S202. In step S203, the control waits until the full-depression switch SW2 is turned on. If it is determined that the full-depression switch SW2 is turned on, a photographing lens is driven according to the ranging result to perform a focusing operation, and a shutter and the aperture are controlled according to the photometry result to perform photographing (exposure) processing in step S204. In step S205, the motor 3a is turned through the motor drive circuit 3, thus starting a winding operation (one-frame feeding operation) of the film 10. After the control waits for a predetermined time in step S206, information such as a photographing date is recorded on the magnetic recording region Dn for the corresponding photographing frame by the magnetic head 2a through the recording and reproduction circuit 2 in step S207. The reason why the control waits for the predetermined time is to start recording after the rotation of the motor is stabilized since a film feeding amount cannot be stabilized at the beginning of rotation of the motor. In step S208, it is checked if the photographing frame (a frame photographed in step S204) is the last frame (36th frame). In this checking step, the number of frames is counted in every photographing operation, and if it is determined that the count result has reached a predetermined value, the last frame can be determined. If NO in step S208, the flow advances to step S209, and the control waits for the end of the information recording operation. If the recording operation is ended, the control waits in step S210 until the first perforation P(n+1)a of the next frame is detected. More specifically, if the corresponding photographing frame is F35, the control waits for detection of the perforation P36a. When the perforation P(n+1)a is detected, the flow advances to step S211 to start a damping operation for stopping the film, and the flow then advances to step S212. In the damping operation, in order to precisely stop the frame of the film 10 at a position opposing the aperture AP, a voltage is intermittently applied to the film feeding motor 3a to drive the motor at a low speed. In step S212, the control waits for detection of the second perforation P(n+1)b of the next frame. If it is determined that the second perforation P(n+1)b is detected, the drive operation of the motor 3a is stopped in step S213, and the motor is braked and stopped in step S214. Thereafter, the processing is ended. On the other hand, if it is determined in step S208 that the photographing frame is the last frame, the flow advances to step S215 to set a measurement time of the timer. In step S216, the timer is started. The setting time is a film feeding time required for recording information for the last frame, and is determined in advance by the camera. In step S217, the control waits for the end of magnetic recording. When the magnetic recording is ended, the control waits until the time measured from the start of the timer reaches the setting time (until time-up). When the setting time is reached, the film winding operation is stopped in step S219. In step S220, the motor 3a is reversed to start a rewinding operation of the film. In step S221, the control waits for completion of the rewinding operation. When the rewinding operation is completed, the motor 3a is stopped in step S222, thus ending the processing. According to the above-mentioned sequence, the film is wound by one frame upon completion of a photographing operation of each frame, and information for the photographing frame is recorded on the magnetic recording region of the film 10 in the winding operation. If it is determined that the photographing frame is the last frame (36th frame), time measurement is started, and thereafter, a film winding operation is performed until information recording is ended and a predetermined time passes. As a result, a state shown in Fig. 4B is established. Thereafter, the rewinding operation of the film 10 is started. According to this embodiment, since the winding operation for one frame (indicated by FS in Figs. 4A and 4B) is performed after the photographing operation of the last frame, information can be reliably recorded for the last frame. In the arrangement of the above embodiment, the motor drive circuit 3 and the motor 3a constitute a winding means 101, the photo-electric detection circuit 1, the photosensor 1a, and the control circuit 4 constitute a determination means 103, and the control circuit 4 constitutes a control means 104. In place of using the timer, the film winding operation may be stopped when the end of information recording is determined in step S217. When information recording is ended upon detection of the first perforation P(n+1)a of the next frame, only the time-up determination may be executed. In the above embodiment, the predetermined time to be set in step S215 is determined beforehand. However, as shown in, e.g., Fig. 6, an actually measured film feeding time may be used. In Fig. 6, processing operations until step S205 are the same as those in Fig. 5, and a detailed description thereof will be omitted. After the film winding operation is started in step S205, a timer for measuring a film feeding time is started in step S301. Thereafter, the processing operations in steps S206 to S210 described with reference to Fig. 13 are executed. If YES in step S210, the timer is stopped in step S302. In step S303, the time measured by the timer, i.e., a time required for winding the film by one frame, is stored, and the flow then advances to processing in step S211 and subsequent steps. The stored time is used in step S215. Thus, the winding operation for one frame can be performed after the photographing operation of the last frame like in the above embodiment. Figs. 7 and 8 show still another embodiment using two photosensors. Fig. 7 shows a state wherein a recording operation for the last frame is ended, and a frame FS opposes the aperture AP. In Fig. 7, the photosensor 1a shown in Fig. 2 is arranged at a position PSp, and the other photosensor is arranged at a position PSs1. Fig. 8 shows a control sequence, and processing operations until step S208 are the same as those in Fig. 5. If the last frame is determined in step S208, the flow advances to step S401 to enable an input from the photosensor at the position PSs1. In step S402, the control waits until the photosensor detects a perforation. If the photosensor detects the perforation, a count-up operation is performed in step S403, and the flow advances to step S404. In step S404, it is checked if the count value is 3. If NO in step S404, the flow returns to step S402; otherwise, the flow advances to step S405. In step S405, the film winding operation is stopped, and in step S406, the film rewinding operation is started. The subsequent processing is the same as that in step S221 and subsequent steps in Fig. 5. When the film winding operation is started from a position where the last 36th frame opposes the aperture AP, a perforation detected in the third detection by the photosensor at the position PSs1 is PA. In this case, the relationship between the film 10 and the magnetic head 2a is set in a state wherein the recording operation of the 36th frame is completed, as shown in Fig. 7. Therefore, when the winding operation is stopped when YES is determined in step S404, information recording can be reliably performed for the last frame like in the above embodiment. The other photosensor may be arranged at a position indicated by PSs2. In this case, a perforation detected in the second detection is PA. Fig. 9 shows an embodiment wherein the last frame is determined upon detection of the perforation PA. In Fig. 9, processing operations until step S205 are the same as those in Fig. 5. After the winding operation is started in step S205, a PA detection timer is started in step S501. Thereafter, the control waits for a predetermined wait time in step S502, and information recording is then started in step S503. In step S504, it is checked if a perforation is detected. If YES in step S504, it is determined that the perforation PA is detected, i.e., the photographing frame is the last frame, and the flow advances to processing in step S401 and subsequent steps. If NO in step S504, it is checked if a predetermined time passes from the start of the timer (time-up). The predetermined time in this case is a time from a state wherein the perforation P36a is detected until the perforation PA is detected. More specifically, as described above, since the interval between the perforations P36b and PA is shorter than the interval between the perforations P(n-1)b and Pna (n = 1 to 36), if the perforation is detected before time-up, this means that the detected perforation is PA. If NO in step S505, the flow returns to step S504; otherwise, the flow advances to step S506. In step S506, the control waits for the end of recording. If the recording is ended, processing in step S210 and subsequent steps is executed. The position of the photosensor 1a is not limited to that in the above embodiment. For example, as shown in Fig. 10, the photosensor 1a may be arranged immediately above the magnetic head 2a. In this case, as shown in Fig. 11, after YES is determined in step S208, the control waits for detection of a perforation in step S601. If the perforation is detected, a count-up operation is performed in step S602. If it is determined in step S603 that the count value has reached 2, i.e., if the perforation P36b is detected, the winding operation is stopped in step S604, and the rewinding operation is started in step S605. Thus, information recording for the last frame can be reliably performed like in the above embodiment. In the above description, a winding operation for one frame or more is performed to allow information recording after a photographing operation of the last frame. However, when a time required for information recording is shorter than a time required for winding one frame, the film may be wound by an amount less than one frame. That is, the film need only be wound by at least an amount capable of recording information for the last frame. The 36-frame film has been exemplified. However, the present invention may be applied to films having various other numbers of frames. Furthermore, in the above description, the magnetic recording region for each frame is formed immediately below the frame. However, the magnetic recording region may be formed above each photographing frame. Moreover, the present invention is not limited to magnetic recording. For example, information may be optically recorded.

Claims: A camera comprising: film feeding means (3,3a,101) for winding a film by one frame upon completion of a photographing operation of a frame; recording means (2, 2a) for recording information for a photographed frame in a recording region of the film (10) as the film (10) is wound; characterised in that the camera further comprises: determination means (1, 1a, 4, 102) for determining whether the photographed frame is the last frame; and control means (4, 103) for controlling said film feeding means to wind the film (10) by at least an amount sufficient for recording information for the last frame after it is determined that the photographed frame is the last frame, to effect recording of the information for the last frame on the film during the winding and to stop the film winding before the film is entirely drawn out from the film cartridge. A camera as claimed in claim 1 wherein said recording means comprises a magnetic head (2a) capable of magnetically recording information on a magnetic recording region in a film. A camera as claimed in any preceding claim wherein said determination means (1, 1a, 4, 102) comprises a photosensor (1a) and a timer. A camera as claimed in any preceding claim where said determination means (1, 1a, 4, 102) is for detecting a specific perforation near the last frame (F36) of the film.

Inventors: KAZAMI KAZUYUKI, YOKONUMA NORIKAZU, KAZAMI, KAZUYUKI, YOKONUMA, NORIKAZU
Applicants: NIPPON KOGAKU KK, NIKON CORPORATION
Application year: 1991
Main classification: G03B1
IPC codes: G03B1, G03B17