JPH043135A - Cassette tightening device for microfilm reader - Google Patents

Abstract

PURPOSE:To allow the execution of always correct tightening by setting the rewinding quantity corresponding to the magnitude of inertia moment and executing rewinding. CONSTITUTION:A moment discriminating means 116 discriminates the magnitude of the inertial moment in accordance with the speed at the time of lapse of a specified period of time after a motor 62 is started by a tightening start signal (a). Namely, the revolutions of an armature 62A of the motor is detected by an encoder 118. Memories 120, 122 store the number of revolutions of the motor during the time after the starting of the motor. The increased quantity of the number of revolutions at this time width is determined by a subtractor 124 and the set value of a setting unit 126 is compared by a comparator 128. The tightening quantity corresponding to the magnitude of the discriminated inertia moment is determined. The always correct tightening is executed in this way even if the magnitude of the inertia moment changes.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cassette winding device for a microfilm reader that winds a film by rotating a cassette reel in a winding direction when loading a cassette.

(Technical Background of the Invention) In a microfilm reader printer, when a cassette containing microfilm is loaded into a league, a loading mechanism pulls out the leading end of the film from a supply reel (hereinafter referred to as cassette reel) in the cassette and winds it. Wind it onto the take-side reel and search. The film may be loose in the cassette before it is loaded into the league, and if you load the cassette with the film loose, the loading mechanism may not be able to pull out the leading edge of the film correctly, or the film may be loose. There was a problem that it could damage the

Conventionally, when a cassette is loaded, a reel within the cassette is rotated in the rewinding direction for a certain period of time, and the film is wound tightly using the film's own moment of inertia. However, in this case, the rewinding time was set to a constant value, so when the number of film rolls (length) is small and the film is thin, the moment of inertia of the film is too small and the reel rotates at high speed. However, when the knoll was stopped, the film sometimes loosened due to inertia. On the other hand, if the moment of inertia of the film is large, the winding may be insufficiently tightened.

(Objective of the Invention) The present invention has been made in view of the above circumstances, and is designed to always maintain correct operation even if the moment of inertia of the film changes due to changes in the number of rolls of film stored in a cassette, the thickness of the film, etc. To provide a cassette winding device for a microfilm reader which can tighten the film and prevent the film from loosening significantly when the reel is stopped.

(Structure of the Invention) According to the present invention, this object includes a control means for tightening the cassette reel in the film rewinding direction when loading a cassette containing a cassette reel wound with microfilm. a rewinding motor that rotates the film in the rewinding direction; a moment determining means that determines the magnitude of the moment of inertia of the film wound on the cassette reel; and a rewinding amount that corresponds to the determined magnitude of the moment of inertia. This is achieved by a cassette tightening device for a microfilm reader, which includes a rewinding amount setting means and performs rewinding by the set rewinding amount.

Here, the magnitude of the moment of inertia can be determined based on the speed after a predetermined time has elapsed after starting the motor, the degree of acceleration, that is, the change in speed over time, and the like. Further, the rewinding amount can be set by time using a timer or by the number of rotations.

(Embodiment) FIG. 1 is an overall schematic diagram of an embodiment of the present invention, FIG. 2 is a perspective view of a part thereof, and FIG. 3 is a block diagram of the main part thereof.

The roll microfilm 2 used in this embodiment is stored in a cassette 8 and loaded into the league printer device 10.

The league printer device 10 is configured as shown in FIG. That is, the front of the case 12 (right side in Figure 1)
A transmissive screen 14 is arranged on which the image of the film 2 is enlarged and projected. Cassette 8 is screen 1
4 is loaded into the loading section 16 located below. At this time, the supply reel (cassette reel) 18 in the cassette 8 is rotated in the rewinding direction of the film 2 to tighten the film, the mechanism of which will be described later. The leading end of the film 2 wound on the reel 18 is pulled out by a loading mechanism and wound on the take-up reel 20. A light source 22 is arranged below between both reels 18, 20. The light emitted from this light source 22 passes through the film 2, passes through the projection lens 24, the image rotation prism 26, and a plurality of reflection mirrors 28.3.
The light is guided to the screen 14 through an optical system consisting of 32, 32, and the like. As a result, the image information recorded on one frame of the film 2 is enlarged and projected.

A mirror 34 that can move forward and backward on the optical axis is provided between the reflecting mirrors 28 and 30, and during printing, image projection light is transmitted to a printer device 36 located below by this mirror 34.
lead to. 38 is a masking device that blocks the incidence of a part of the projection light.

The film advance mechanism is shown in FIG. Cassette 4
is loaded into the loading section 16, the micro switch 4
0 detects this and winds the film 2 in the cassette 8 onto the reel 18 by a winding device 100 to be described later. That is, when the cassette 8 is loaded, the rotating shaft of the motor 62 is automatically connected to the cassette reel 18, and the reel 18 is rotated for a short time in the unwinding direction (in the direction of arrow B in FIG. 2).

After this tightening, the film 2 is loaded by the loading mechanism.
The leading end of the tape is drawn out and wound on the take-up reel 20. That is, a roller (not shown) is brought into rolling contact with the reel 18 through an opening 4a provided at the bottom of the cassette 4, and the leading edge of the film 2 is drawn out and wound around the take-up reel 20 via guide rollers 42, 44. The film 2 is placed near the guide rollers 42 and 44.
Sensors 46 and 48 are provided to detect the presence or absence of.

An endless belt 50 is pressed against the winding wheel 20 and tightly contacts the film 2 being wound there. This endless belt 50
are guide rollers 52, 54, 56 and drive rollers 58
is wrapped around.

The drive roller 58 is driven by a motor 60 and the belt 5
0 in the direction of arrow A, that is, in the winding direction. As a result, the film 2 is wound onto the reel 20 while being sandwiched between the belt 50 and the reel 20. The film 2 is rewound by driving the reel 18 in the direction of arrow B by the motor 62. At this time as well, the belt 50 runs together with the film 2.

A tension roller 64 is pressed against the endless belt 50 with a predetermined pressure to apply appropriate tension to the belt 50.

The rotation speed of the tension roller 64 is detected by an encoder 66. Based on the output pulse signal of the encoder 66, the traveling distance of the endless belt 50, that is, the traveling distance of the film 2 is determined.

Behind the screen 14, the CCD line sensor 78 is held by a movable plate 80, and the movable plate 80 is movable left and right on guide rails 82 and 84. This movable plate 80 has a pair of pulleys 86.8 as shown in FIG.
Both ends of the wire 90 wound around the wire 8 are fixed.

The pulley 88 is rotated by a motor 92, and a wire 90 running therewith moves the movable plate 80 left and right. The line sensor 78 moves within the width of the screen 14 to read the projected image, and for example outputs the image to a link (not shown).

Next, the seaming device 100 according to the present invention will be explained based on FIG. 3. This device 100 constitutes a part of motor control means.

In this embodiment, a DC series motor is used as the motor 62, and its armature 62A and field 62B are connected in series to an AC power source 108 along with forward/reverse changeover switches 102a, 102b, triac 104, and shunt resistor 106. . 1) 0 is a gate circuit that controls the motor drive current by changing the conduction rate of the triac 104. That is, the voltage ■1 indicating the set torque T0 set by the variable resistor 1)2 and the shunt resistor 10
A subtracter 1)4 calculates the difference (VI V2) between the voltage v2 indicating the motor drive current detected by the gate circuit 1) and the voltage v2 detected by the gate circuit 1).

A gate signal G whose phase changes in accordance with Vz) is supplied to the gate of the triac 104. As a result, the motor drive current 1 is maintained at the current 1 that provides the set torque T0 set by the variable resistor 1)2.

1) Reference numeral 6 denotes moment determining means for determining the magnitude of the moment of inertia of the film wound on the cassette reel 18. The moment determining means 1) 6 determines the magnitude of the moment of inertia based on the speed at the elapse of a certain period of time after the motor 62 is activated by the tightening start signal a.

That is, the rotation of the armature 62A of the motor 62 is detected by the encoder 1) 8, and the memories 120 and 122 respectively store the time t after activation of the motor 62 and the number of revolutions N, , N, rotated by t2. And this time width △t=tx
The amount of increase in the rotational speed between t+ and ΔN=N2−N is determined by a subtracter 124, and compared with the set value ΔN0 of a setter 126 by a comparator 128. That is, the average rotational speeds within the time width Δ are compared.

In FIG. 4A, the solid line shows the case where the moment of inertia is large and the acceleration is slow, and the dashed line shows the case where the moment of inertia is small and the acceleration is fast. The comparator 128 indicates that when the rotational speed increase amount ΔN within a certain time Δ is a solid line, it is small (Δ
In the case of N+<ΔN, ), - dotted chain line, it is large (ΔN,
>ΔN, ), the magnitude of the moment of inertia is determined.

Reference numeral 130 denotes a rewinding amount setting means for determining the rewinding amount corresponding to the determined magnitude of the moment of inertia. This method 1
28 starts integration of time based on the tightening start signal a of the motor 62, and calculates time integration for different fixed times j- and tb.
It has timers 132 and 134 that output a tightening stop signal after (t-<tゎ), and a changeover switch 136. This changeover switch 136 is connected to the moment discriminating means 1 described above.
) 6, if the moment is large, timer 1 is activated.
34 signal, and timer 13 when the moment is small.
2 signals are respectively guided to the gate circuit 1)0, and the output of the gate signal is stopped.

In other words, the seaming is stopped.

In the moment determination means 1) 6 of this embodiment, the motor 62
Although the magnitude of acceleration is detected from the average speed after a predetermined period of time, the present invention can also detect using changes in rotational speed, acceleration, etc. instead of determining this average speed. For example, as shown in FIG. 4B, the motor drive current I becomes a large current (rush current) at the moment the power is turned on, and then the motor 62
Since it decreases with acceleration of current (2), the decreasing speed of this current (2) may be detected. In this figure, the solid line indicates the case where the moment is large, and the dashed-dotted line indicates the case where the moment is small. It's big. Therefore, in this case, memory 1
20.122, the setting device 126 sets the currents I, , I2 . Setting current △work.

Remember.

In addition, instead of changing the current, the rotational speed can be detected by using the fact that the back electromotive force generated across the armature 62A changes in a nearly constant relationship with the rotational speed. The moment may be determined from the change in .

Furthermore, the moment determining means 1) 6 may differentiate the rotational speed using a differentiating circuit to obtain acceleration, and may determine the magnitude of the moment based on the magnitude of this acceleration.

On the other hand, the rewinding amount setting means 130 may set the rewinding amount using the rotational speed N, , NI, instead of setting the rewinding amount based on the times t1 and tb. In this case, timer 132.134
is configured to monitor the rotational speed N of the motor 62 after starting, and output a stop signal when this reaches N, , Nl.

In this embodiment, the motor 62 is a DC series motor, and its speed is controlled by a triac 104, but it is of course possible to use other types of motors or control elements such as SIRIS.

In addition, the moment of inertia may be determined not only in two stages, large and small, but also in a stepless and continuous manner, and the rewind amount may also be set in a continuous and stepless manner according to this magnitude. .

(Effects of the Invention) As described above, the present invention determines the magnitude of the moment of inertia of the film wound on the cassette reel, and changes the amount of rewinding based on the result of this determination. Correct seaming can always be performed even if the size of the seam changes.

Therefore, if the moment of inertia is extremely small, the tightening time or rotation speed can be set small.
There is no problem that the film becomes loose when the cassette reel stops due to excessive speed.

[Brief explanation of the drawing]

Fig. 1 is an overall schematic diagram of an embodiment of the present invention, Fig. 2 is a perspective view of a part thereof, Fig. 3 is a block diagram of the main part, and Fig. 4A, E
The figure is a characteristic diagram of changes in rotation speed and current when the motor is started. 2... Microfilm, 8... Cassette, 10... Reader link device, 18... Cassette reel, 62... Rewinding motor, 1) 6... Moment discrimination means, 130... Rewind amount setting means.

Claims (4)

[Claims] (1) A rewind motor that rotationally drives the cassette reel in the rewind direction, in a device having a control means for tightening the cassette reel in the film rewind direction when loading a cassette containing a cassette reel wound with microfilm; and moment determination means for determining the magnitude of the moment of inertia of the film wound on the cassette reel;
A cassette tightening device for a microfilm reader, comprising a rewinding amount setting means for setting a rewinding amount corresponding to the determined magnitude of the moment of inertia, and rewinding the set rewinding amount. (2) The cassette tightening device for a microfilm reader according to claim (1), wherein the moment determining means determines the magnitude of the moment of inertia based on the motor speed after a predetermined time elapses after the motor is started. (3) The cassette tightening device for a microfilm reader according to claim (1), wherein the rewinding amount setting means comprises a timer for setting a rewinding time. (4) The cassette tightening device for a microfilm reader according to claim 1, wherein the rewind amount setting means comprises a rotation speed setting device for setting the rewind rotation speed.