JPS59121036A - Set position stopping method of lens system for variable power copying device - Google Patents

Abstract

PURPOSE:To stop quickly and exactly a titled lens system at a set position by providing an encoder for converting an extent of movement or a position to an electrical signal of plural bits along the moving direction of the lens system, and decelerating the movement when the lens system reaches near the set position of a stop. CONSTITUTION:When a brush part 29 scans a plate part 28, an output of an encoder 27 is different by a position of the brush part 29, therefore, a position of a lens system can be detected by the output of the encoder 27. Subsequently, a magnification signal operated by a copying device and a signal of the encoder are calculated by a comparing circuit, and in case of coincidence, a motor 23 is not driven. On the other hand, when the magnification signal is different from an output signal of the encoder, an output is transmitted by the comparing circuit, the lens system is moved by driving the motor 23 by a motor controlling circuit, and when the output signal of the encoder coincides with the magnification signal by the movement of the lens system, the movement of the lens system is stopped. Accordingly, the magnification can be varied continuously, and also an overrun, etc. due to the movement of the lens system scarcely occur, therefore, no error is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a variable magnification copying apparatus, characterized in that a lens thread movable in the optical axis direction is precisely stopped at a set position by an encoder. The present invention relates to a method for stopping a lens thread at a set position.

As is well known, a variable magnification copying device enlarges the original to 9 equal magnification or reduces it by moving a lens thread installed inside, or the magnification of the original changes depending on the position of the lens system, so it can accurately reproduce the image. Must be positioned.

Lens thread position 1 of the conventionally known variable magnification subject device k
There are two methods for changing the method: a mechanical method using a feed screw and a nut (Japanese Unexamined Patent Publication No. 133756), and a method using a motor rC operated by the number of electric pulses (Japanese Unexamined Patent Publication No. 1156-39).
565 (Japanese Patent Laid-Open No. 57-120962), a method of counting signals generated in response to lens movement (Japanese Patent Laid-Open No. 120962/1983)
and so on.

However, in any of the above cases, the position *'i of the lens thread is not directly detected from the lens thread. Therefore, the position of the lens thread set by operating the variable magnification copying device,
There are many cases in which the copying magnification changes due to a difference in the position where the lens system stops when printing, and especially when a copying machine is used for a long period of time, the frequent movement of the lens system back and forth causes p-back. As rush occurs, the positional error gradually increases. In addition, in order to stop the lens thread at the set position quickly and accurately, it is desirable to move the lens system quickly when it is far from the set position and slow it down when it reaches near the set position. Then, if the movement of the lens thread is slowed down to the set position (1) and made faster, even if sudden braking is applied, the lens thread will pass through the set position due to movement inertia, so the lens thread must be moved in the opposite direction. If this movement is repeated several times, it will not only waste time when stopping, but also cause an error in the stopping position.

The present invention has been proposed in view of the above, and includes an encoder that converts the moving position or mechanical position of the lens system into an electrical signal of counting bits along the moving direction of the lens system, and when the lens system is near the set stop position. 1, the movement is decelerated to quickly and reliably stop at the set position.

The present invention will be explained below with reference to embodiments of the drawings.

In Figures 1 to 3, two support rods 1 and 2 are provided in parallel to each other in the length direction on the horizontally long support stand that supports the lens ii, and a lens system 3 is installed on both support rods. The movable frame II is placed movably.

The movable frame Hiroshi integrally has a first lens frame 6 to which the first lens 3 is attached, and a third lens frame t to which the third lens 7 is attached, and both support rods and - are not supported. can move freely back and forth. A support rod and a guide rod 9 are provided on the flat material on one side of the Sakura motion bracket, and the guide rod 9 has a position between the first lens 3 and the third lens.
The cylindrical bearing part /S of the first lens frame // provided with the first lens 30 and the cylindrical bearing part /S of the first lens frame /G provided with the first lens 3 located outside the third lens 7 and
Make it possible to move along the entire kite frame//41 in the 1st collens frame // and the 3rd frame frame/41. J: Both lens frames // and /tei have their protruding ends supported by support rods, so they move together with the moving frame, and can also be moved independently along the guide 5-rod 9.

Each bearing part /λ, 15 of both lens frames //, /II has guide bins /2', /!, respectively. r'f protruding cam plate/AK vertically movable cam plate provided on the front curve of the movable frame DA; vertical cam hole 17; lrK each of the above guide bins/2'
, /? Insert completely. Further, the cam plate /6 is provided with protrusions /9 extending laterally, and the protrusions 19 are made to face a control plate provided longitudinally on the support base /. The upper edge 21 of the control plate is gently sloped upward from one end to the other, and a protrusion is placed on the upper edge.

Therefore, when the moving frame moves along the support rod, the cam plate /A also moves, but the protrusion /? is the upper part of the control board, 2/
, the cam plate 16 moves in the vertical direction. As a result, each cam hole/7゜moves vertically, so each lens frame that does not move vertically//:/Hiro can be moved independently by the guide rod 9 with the guide bin/ko', /&'.
The distance between each lens element changes depending on the position of the moving frame DA, resulting in a state corresponding to the magnification.

The support stand l6- moves the moving frame 4I mentioned above. Due to the operation of the drive mechanism n provided in the.

This drive mechanism includes two motors 23 that can rotate in forward and reverse directions.
, #1 AIJIJ @ 2 da rotated by the mokuco, a plurality of idle wheels J, an endless material hung on the driving wheel Koda and the idle wheel J, and the endless material 2A is connected to the moving frame. Attach to da. Therefore, when the mower 3 is driven and the two driving wheels rotate, the endless member 2A runs and the movable frame 1 moves along the support rod to appropriately adjust the distance between each lens, and when it stops, the lens system becomes the set appropriate magnification.

Note that a chain foil and a chain can be used as the driving wheel, the idler wheel, and the endless member, but those having other structures may also be used.

In the lens system of the above-mentioned copying machine, the position of the lens system must be properly set by external operation of the copying machine. In other words, since the magnification of the manuscript can be changed in multiple stages at the magnification library, when there is a signal for the desired magnification,
The lens system must be moved by 1 to a position where the magnification is achieved.

-7- For this purpose, the present invention uses an electrical or mechanical encoder for converting the amount of movement or mechanical position into a multi-bit electrical signal in the lens system. According to the embodiment shown in the drawings, this encoder includes a plate 8IS2g provided on the support base along the moving direction of the lens thread 3, and a brush portion 29 provided on the movable frame in contact with the surface of the plate portion 2g. The grate part 2g has a horizontally long flat plate shape and has a plurality of bit output terminals 30'ft at one end, and the surface has rows in which conductive parts and non-conductive parts are arranged differently for each output terminal. 37
A different digital number of 1 m of rubit is determined for each position of the plate portion.

When I inspected the flan section 29 and the plate section, I found that
Since the output of the encoder varies depending on the position of the brush portion 2t, the position of the lens thread can be detected by the tk encoder output. Then, the magnification signal operated in the copying machine and the encoder signal are calculated by a ratio soft circuit, and if they match, the motor 3 is not driven. In this case, the magnification for copying and the position of the lens system match.

However, if the magnification signal operated by the copying machine and the output signal of the encoder are different, the comparison circuit outputs it? The motor is driven by the motor control circuit to move the lens thread upward, and when the output signal of the encoder and the magnification signal match due to the movement of the lens system, the movement of the lens thread is stopped.

In this case, it is desirable to distinguish the output signal based on the difference between the encoder's output number and the magnification signal, and then use the type of this level signal to cause the motor control circuit to identify the moving direction of the lens thread and move it over the shortest distance. Yes.

FIG. S is a block diagram for electrically controlling the movement of the lens system 3, that is, the movable frame, and is a block diagram for electrically controlling the movement of the lens system 3, that is, the moving frame. In 2, the stopping film position *bk of the lens thread can be determined freely, and the case where the lens thread is in the position [a VC] will be explained.

The numerical position (l-bit) representing position tt is assumed to increase from left to right, and when the motor blade is rotated to the left, the number 9-value α is assumed to decrease, that is, the encoder brush and lens thread move to the left. do. When the lens system moves from position α toward the set position, if it moves from left to right, that is, under the condition α<b, the lens system is intensified or slowed down from the position c = b - y. , the lens system goes from right to left.

In other words, when moving with the condition α〉b, If−d=b+
It is assumed that the lens system is intensified or speed-reduced from the X position. In this case, -e and d are positions separated by predetermined numbers x and v from the position, and z and y may be the same or different. If α<b−c and α<C, then
First, due to α<b output “H” of the digital comparator 33, “
H# is applied, causing the motor 23 to rotate to the right and moving the lens system 3 from left to right. At this time, and gate J
The output of the digital converter 33a (b) is also given to "H", but as will be explained later, the input of the AND gate 33 is L#.

Manual switching of the drive power mode switching circuit 36 37Fi"Lu
10-. Therefore, the output of the switching circuit 3A is in continuous current supply mode, and the rotation of the motor 23 is high speed or steady. −
The calculation y=c is performed and applied to the reference input of the digital comparator 3D.

Therefore, the value of α is incremented, and α〉C
Or when α〉C, α) of the digital comparator 3)
C (a≧C output rises to “H#”, AND gate 3
The AND at S is obtained and "H" is applied to the input 37 of the drive power mode switching circuit 36, and the current supply mode in this switching circuit 36 changes from intermittent to conduction angle control mode, and the drive of the motor 23 changes from intensive to low speed. becomes.

In this state, when α=b, α<b output=“falls to L#, or when the motor circuit direction control circuit 31I has the stop force as shown by the chain line in FIG. 3, α=b output=1H#
When the motor 23 rises to V, the motor 23 instantaneously stops at position [b], causing an overrun or an unreasonable stop at -7.

On the other hand, if the lens thread 3 is a ) b, then α < d = b + X or a < d, then a (
d (α≦d) output and α of digital converter 33
B output causes the AND gate Reno to output "H11", and this "H" output causes the dynamic power mode switching circuit 3A""C to change the power supply mode from intermittent to conduction angle control, and the drive of the motor 23 changes to inching. to low speed, so the movement of the lens thread 3 becomes slow.Then, as described above, when α-b VC occurs, the motor tacho 3 stops instantaneously.And in any case, even if the lens system overshoots the position wb, , moves at low speed in the opposite direction and stops at the position - Note that OR gate ≠ 2 means both AND 3 above!;.

Interference prevention for lI/ is available.

The driver head mode switching circuit 36 can be easily constructed using known techniques using semiconductor devices or the like.

Furthermore, instead of conduction angle control, in the case of a synchronous motor, frequency modulation may be used to slow down the V drive. That is, it may be possible to switch between a high frequency current mode in a steady state and a low frequency current mode at a low speed.

To summarize, according to the present invention, the position of the lens system to be moved T#tJ is directly detected by the fk encoder, and the movement of the lens thread becomes slow near the stop position, so the lens thread can move and stop very quickly. become. Instead of using a scale that can electrically freely set the low speed range of the lens system's movement, an encoder can detect a large number of unique positions with minute lengths depending on the number of bits, making it possible to change the magnification steplessly. Since there is almost no overrun caused by the movement of the metal, there is no difference in accuracy.

In the embodiments of the present invention, the lens thread is of the basic symmetrical type II.
Although shown as a group zoom lens, lens systems having other configurations may be used. Furthermore, the encoder is not limited to one consisting of a plate part and a brush part, but may be an electrical or mechanical one with other configurations.

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[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 7 is a plan view, FIG. 2 is a front view, FIG. 3 is a partially cutaway front view, and FIG. 9 shows a part of the encoder grate. The plan view shown and FIG. 3 are block diagrams. Patent applicant: Tokina Optical Co., Ltd. Agent: Fuku 1) Credit: Kenzo, ・1. Pa111

Claims (1)

[Claims] An encoder is provided that converts the amount of movement or place W in the moving direction of the lens system that can be moved along the optical axis direction into an electrical signal of counting bits, and a magnification signal and encoder are generated by operating an operating section provided in the copying machine. When there is a difference in the image signal, the lens system is moved toward the position set by the operation unit, and near the set position, the movement of the lens thread is intensified or slowed down by electrical control. A method for stopping a lens thread for a variable magnification copying device at a set position, which is characterized in that the lens thread is moved and stopped at the set position.