JPH0664292B2 - Roll film end detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention, when winding or rewinding a roll film used in a reader printer or the like, is designed so that the end of the roll film in the feeding direction of the roll film is Relates to a method for detecting.

[Conventional technology]

In general, regardless of whether each frame of the roll film is automatically searched or visually searched, when the feeding operation is performed by a driving means such as a motor, the roll film is It may be sent to the end. In particular, when the end of the roll film is fixed to the rotation shaft of the reel, if the roll film or its drive system is damaged, or the drive motor is abnormally heated, etc. It causes an accident.

Therefore, conventionally, various means have been proposed for detecting the end of the roll film.

For example, a mark indicating the end of the film is provided near the end of the roll film itself, and means for forcibly stopping the film feeding operation when this mark is detected, or a mark for counting the number of frames on each frame of the roll film is provided. There have been proposed means for providing and counting the number of passages of this mark, and for determining the end when the next mark is not detected even after a set time has elapsed.

However, in the means for providing the mark on the roll film itself, it is necessary to separately provide means for detecting the mark, which is disadvantageous in that the device configuration becomes complicated, and the frame which is no longer needed from the roll film. When cutting off or adding a piece such as adding pieces, it is not practical because other than this editing work, it is necessary to change the mark position indicating the end, change the number of set marks, etc. There is inconvenience.

Therefore, in order to detect the end without providing a mark for detecting the end on the roll film itself,
There has been proposed a means for providing an encoder that outputs a pulse signal corresponding to film feeding, counting the number of output pulses from this encoder, and detecting the film end based on the counting result. (See JP-A-57-177135) [Problems to be Solved by the Invention] However, in the means for counting the number of output pulses of the encoder and detecting the end, the film feed amount is detected. It is necessary to separately provide the encoder and the counting means therefor, which is disadvantageous in that the device configuration becomes complicated and expensive.

The present invention has been made in view of the above circumstances, and an object thereof is to be able to detect a film end without providing a sensor or the like for detecting a film feed amount such as an encoder in which the apparatus configuration becomes complicated and expensive. To do.

[Means for solving problems]

The feature of the method of the present invention is that the ratio of the counter electromotive voltage of the drive motor of the supply side reel wound with a roll film and the counter electromotive voltage of the drive motor of the winding side reel that winds the roll film, Whether or not the winding of the roll film to the take-up reel is completed is detected based on whether or not there is a set ratio or more corresponding to the rotation ratio of each reel at the end of winding of the roll film to the take-up reel. The point is and the action is as follows.

[Action]

That is, the number of rotations of the reel required to wind the roll film on the take-up reel to the end of the film corresponds to the length of the roll film wound on the supply-side reel, that is, the winding diameter. It is proportional to the ratio of the rotation speed of the reel and the rotation speed of the winding side reel. Therefore, if the ratio of the numbers of rotations of the supply-side reel and the winding-side reel can be detected, it can be determined whether or not the end or the vicinity thereof has been wound. Since the number of rotations of each reel has a proportional relationship with the counter electromotive voltage of the drive motor that drives each reel, the counter electromotive voltages of the drive motors of the supply-side reel and the winding-side reel are It is possible to detect whether or not the roll film has been wound up to the end by detecting and determining whether or not the ratio is equal to or higher than the set ratio.

〔Example〕

 An embodiment of the method of the present invention will be described below with reference to the drawings.

FIG. 4 is a perspective view showing a schematic structure of a film carrier of a leader printer to which the method of the present invention is applied. The take-up leader (1) pivotally supported by the film carrier and the supply reel detachable from the film carrier. (2), a pair of upper and lower glass plates (3a), (3b) constituting the light irradiation part (3), and the roll film (F) wound around the supply reel (2) on the take-up reel (1) Guide rollers (6a) to guide to
(6b), (6c), a light source (7) for illuminating the light irradiation section (3), a condenser lens system (8) for guiding light from the light source (7) to the light irradiation section (3), the light The projection lens (9) for projecting the image projected on the roll film (F) illuminated by the light transmitted through the irradiation unit (3) onto a screen (not shown), and the winding reel (1). A take-up motor (M ₁ ) which is rotationally driven, and a rewinding motor which rotationally drives the supply reel (2) when the roll film (F) is rewound.
(M ₂ ) is provided.

Then, the winding motor (M ₁ ) or the rewinding motor (M _1
2 ) While operating the roll film (F) in either one of the forward and reverse directions by operating one, the image illuminated by the light from the light source (7) transmitted in the light irradiation section (3) is displayed on the screen. Project it.

Two of the three guide rollers (6a), (6b), (6c)
(6a) and (6b) are provided on the side of the supply reel (1) so as to guide the roll film (F) while sandwiching it from the vertical direction. Then, a disk (10) having a plurality of slits that rotate integrally with the upper roller (6a),
A photo interrupter type optical sensor (11) consisting of a pair of a light emitting element (11a) and a light receiving element (11b) arranged facing each other on both sides of the slit portion is provided, and the optical sensor (11) causes the disk By detecting the light transmitted / blocked by the rotation of (10), a pulse signal synchronized with the rotation of the disc (10), that is, the feeding of the roll film (F) is output. Therefore, the disk (10) and the optical sensor (11) constitute a pulse encoder (12) for detecting the film feed amount. The pulse encoder is used to detect the film feed amount during film search.

Meanwhile, the core diameter of the core diameter (r ₁₎ and the supply reel (2) of the winding reel (1) (r ₂₎ are each a known value, typically have been used of the same diameter. Also, the supply reel
The initial diameter (R) of the roll film (F) wound around (1) is also a known value. Thus, the ratio of the rotational speed of the take-up reel in the winding ends near ₍₁₎ (ω 1) and supply the rotation speed of the reel ₍₂₎ (ω 2), as shown in the following equation (i), the winding take the ratio of the initial diameter (R) of the reel (1) core diameter (r ₁₎ and roll film (F).

ω ₁ / ω ₂ = r ₁ / R (i) Therefore, if the ratio of the rotation speeds of both reels (1) and (2) can be detected as shown in the above formula (i), the roll film (F) It is possible to determine whether or not has been wound up on the take-up reel (1) side.

Then, the respective back electromotive forces (V _R1 ) and (V _R2 ) corresponding to the back electromotive forces of the respective motors (M ₁ ) and (M ₂ ) are the rotation speeds (ω) of the respective reels (1) and (2). ₁ ) and (ω ₂ ), the ratio of this back electromotive force (V _R1 ), (V _R2 ) is the ratio of the core diameter (r of the take-up reel (1) shown in equation (i) above. ₁ ) and initial diameter of roll film (F)
It corresponds to the ratio with (R), that is, as shown in FIG. 2, corresponding to the winding amount of the roll film (F).

As shown in FIG. 1, the film end detection device uses the roll film (F) based on the ratio of the counter electromotive voltages (V _R1 ) and (V _R1 ) of the motors (M ₁ ) and (M ₂ ). D / A conversion for converting the digital drive voltage (-Vin) corresponding to the drive speed output from the CPU (13) as a control device into an analog voltage. Bowl (14), this D / A
Drive voltage of analog value output from converter (14) (-Vin)
A power amplifier (A ₀ ) that inverts and amplifies and outputs a motor drive voltage (V), and the output (V) of this power amplifier (A ₀ ) is the winding motor (M ₁ ) and rewinding motor (M ₂ ) Motor switch (SW) that switches which of the two is supplied, the current detection resistor (R) that detects the current (I) flowing in the winding motor (M ₁ )
s), the voltage drop (IR _M due to the internal resistance (R _M) take-up motor on the basis of the (M ₁₎ across the winding motor to voltage (Vs) generated in the resistor (Rs) (M ₁₎ ) To calculate)
(A _1), the output of the rewinding motor second counter electromotive voltage calculating unit that detects a second counter electromotive voltage generated from _{(M 2) (V R2)} (A 2), said power amplifier (A ₀₎ ( V) and the first counter electromotive voltage calculation (V _R1 ) of the winding motor (M ₁ ) based on the voltage drop (IR _M ) detected by the first computing unit (A ₁ ) Device (A ₃ ), an approximate termination calculator for calculating the ratio of the first back electromotive voltage (V _R1 ) and the second back electromotive voltage (V _R2 ) and outputting an approximate end detection signal (S ₁ ) described later ( A ₄ ), and the drop voltage (IR _M ) and set threshold (Vref)
When the roll film (F) is completely wound around the take-up reel (1) by comparing with (1), a comparator (A) that outputs a complete end detection signal (S ₂ ) which is inverted from "H" to "L" ₅ ). In Fig. 1, (LP
F ₁ ) and (LPF ₂ ) are filters for removing noise from the counter electromotive voltages (V _R1 ) and (V _R2 ) output from the motors (M ₁ ) and (M ₂ ). Similarly, (C ₁ ) and (C ₂ ) are also capacitors for removing noise.

The gain of the first computing unit (A ₁ ) is set so as to correspond to the ratio of the internal resistance (R _M ) of the winding motor (M ₁ ) and the current detection resistance (Rs), The detection voltage (Vs) by the current detection resistor (Rs), the drop voltage by multiplying R _M / R _S
It is configured to output (IR _M ). The current detection resistor (Rs) is the internal resistance of the winding motor (M ₁ ).
(R _M ) has a resistance value that is negligibly small, and the voltage drop (Vs) due to this current detection resistance (Rs) is the first counter electromotive force that calculates the first counter electromotive voltage (V _R1 ). Voltage calculator (A ₃ )
It does not become a calculation error factor of.

Next, the operation of the film end detection device having the above configuration
A description will be given based on FIG. 2 showing changes in voltage of each part.

That is, the motor applied voltage (V) supplied from the power amplifier (A ₀ ) is, as shown in the following formula (ii), the voltage drop (IR _M ) due to the winding motor (M ₁ ) and its counter electromotive voltage. It is the sum of (V _R1 ).

V = IR _M + V _R1 (ii) Therefore, from the motor applied voltage (V), the first amplifier
By subtracting the voltage drop (IR _M ) output from (A ₁ ), the first counter electromotive voltage (V _{R 1} ) of the winding motor (M ₁ ) is obtained. Meanwhile, the rewinding motor (M ₂₎ are take-up motor (M ₁₎ is the winding motor through a supply reel (2) by the winding of roll film (F) when being driven (M ₁ ), It will be indirectly driven by
The output voltage becomes the second counter electromotive voltage (V _R2 ) itself.

Thus, the first inverse electromotive voltage calculator (A ₃₎ first counter electromotive voltage which is an output of (V _R1) is lowered gradually with increasing winding amount of the roll film, the rewinding motor ( The second counter electromotive voltage (V _R2 ) of M ₂ ) increases conversely. Therefore, when the voltage values of the first back electromotive voltage (V _R1 ) and the second back electromotive voltage (V _R2 ) are reversed, the first back electromotive voltage (V _R1 ) and the second back electromotive voltage (V _R1 ) The output signal (S ₁ ) of the approximate terminal calculator (A ₄ ) that calculates the ratio of _{R 2} ) is “H”
It is possible to detect that the roll film (F) has been wound to the vicinity of its end, that is, to the approximate end by reversing from "L" to "L".

By the way, if the end is determined when the roll film (F) is wound up to its end, there is a risk of damaging the roll film (F) if it is wound at a high speed, and each reel ( Since unreasonable force is also applied to 1), (2) and the motors (M ₁ ) and (M ₂ ), the output signal (S ₁ ) of the approximate terminal calculator (A ₄ ) is the roll film (F). The signal corresponds to the approximate end when the coil is wound up near the end. That is, based on the above formula (ii), the second counter electromotive voltage (V _R2 ) generated by the rewinding motor (M ₂ ) is calculated as follows (iii)
As shown in the equation, the voltage is divided by a predetermined ratio (β) and is input to the second counter electromotive voltage calculator (A ₂ ).

Further, when the detection of the complete termination by the comparator (A ₄ ) is described in detail, the voltage drop (IR _M ) output from the first arithmetic unit (A ₁ ) is the roll film (F) on the take-up reel (1). )
When the winding is completed, the winding motor (M ₁ ) stops, the back electromotive voltage (V _R1 ) does not occur, and the voltage (Vs) generated in the current detection resistor (Rs) becomes maximum. , The value of the voltage drop (IR _M ) at the time of this maximum is set to the threshold (Vr
By comparing with ef), the complete termination can be detected.

Then, the CPU (13) receives the approximate termination signal (S ₁ ) and the complete termination signal (S ₂ ) and controls the supply of the drive voltage (V) to the winding motor (M ₁ ), It controls the switching and stopping of the driving speed.

The operation of the CPU (13) for controlling the motor drive speed by receiving the approximate termination signal (S ₁ ) and the complete termination signal (S ₂ ) will be described below based on the flow chart shown in FIG.

First, it is determined whether or not the approximate termination signal (S ₁ ) is in the ON state (step # 1).

If it is not in the ON state, the processing is terminated. If it is in the ON state, the motor drive mode is set at high speed by checking whether the applied voltage (V) to the motor is the high voltage (V _H ). It is determined whether or not the mode is set (step # 2).

When the motor drive mode is the high speed mode, the applied voltage (V) to the motor is an intermediate voltage ( _VL ) corresponding to the medium speed.
And set to medium speed mode (step # 3).

On the other hand, when the motor drive mode is not the high speed mode, it is determined whether or not the complete termination signal (S ₂ ) is ON (step # 4).

Then, if the complete termination signal (S ₂ ) is not in the ON state, the processing is terminated and waits until the complete termination signal (S ₂ ) is brought into the ON state. On the other hand, when the complete termination signal (S ₂ ) is in the ON state, the applied voltage (V) to the motor is set to zero, the winding motor (M ₁ ) is stopped (step # 5), and the processing is ended. To do.

Therefore, the roll film (F) is wound up to the vicinity of its end at a high speed, and until it is completely wound up, the roll film (F) is kept at a medium speed while preventing excessive tension from being generated. When the roll film (F) is completely wound around the winding reel (1), the motor (M ₁ ) is automatically stopped.

In addition, in the present invention, the approximate end and the complete end in the above-described embodiment are collectively referred to as the end of the roll film.

〔The invention's effect〕

Therefore, according to the method of the present invention, the end of the roll film can be detected without providing a sensor or a mark for detecting the end of the roll film.

[Brief description of drawings]

The drawings show an embodiment of a film end detecting device to which the roll film end detecting method according to the present invention is applied. FIG. 1 is a circuit diagram showing a configuration of the film end detecting device, and FIG. FIG. 3 is a flow chart showing the operation of the control device, and FIG. 4 is a perspective view showing a schematic structure of a film carrier of the reader printer. (1) …… Winding reel, (2) …… Supply reel, (M ₁ ) ……
Take-up motor, (M ₂ ) …… Rewind motor, (F) …… Roll film, (V _R1 ) …… Reverse voltage of take-up motor,
(V _R2 ) …… Reverse voltage of rewinding motor.

Claims (1)

[Claims] 1. A ratio of a counter electromotive voltage of a drive motor of a supply-side reel wound with a roll film to a counter electromotive voltage of a drive motor of a take-up reel for winding the roll film,
Whether or not the winding of the roll film to the take-up reel is completed is detected based on whether or not there is a set ratio or more corresponding to the rotation ratio of each reel at the end of winding of the roll film to the take-up reel. Roll film end detection method