JPH07101273B2 - Image projection device - Google Patents

Description

The present invention relates to an image projection apparatus that magnifies and projects an image of an original document illuminated with light from a light source by a zoom lens that is a projection lens. More specifically, the present invention relates to zooming of a zoom lens in an image projection apparatus such as a reader or a reader printer that magnifies and projects an image of a microfilm as a document.

"Prior Art" Zooming by such a zoom lens has been conventionally performed as follows, for example.

In a zoom lens of a system in which zooming is performed between both the maximum and minimum zooming ends instead of the endless system, the zoom lens is automatically stopped when the zooming end is reached.

On the other hand, the zoom lens is loosely inserted into the handle plate for post focus and in order to press the glass surface of the post roll film carrier by its own weight to maintain the correct posture always facing the original such as microfilm. At the same time, it is held by cam rings, pins, etc. so that it can be moved slightly up and down.

"Problems to be Solved by the Invention" By the way, the following problems have been pointed out in such a conventional example.

That is, the zoom lens is stopped when it reaches the zooming end, but due to the urging force accompanying this stop, the tilt from the constant posture facing the glass surface of the roll film carrier, that is, the microfilm or the like occurs. It was
This is due to the achievement of the above-mentioned holding mechanism for the zoom lens, and since the magnification when setting the zoom lens varies, the zoom drive mechanism first tries to rotate the zoom gear by about its maximum rotation angle, and therefore the zoom lens This is caused by zooming and stopping at the position corresponding to the variable magnification end in the middle.

In this way, the zoom gear rotated to transmit the drive from the zoom drive mechanism and the drive gear thereof are twisted,
Since the zoom lens is also tilted, it is not easy to use and is unsightly, and there is a problem in operability. Furthermore, damage to the cam ring, pins, etc., which is the holding mechanism of the zoom lens, and damage to the zoom gear, its drive gear, etc. occurred. .

In the conventional example, the above problems have been pointed out.

The present invention has been made in view of the above circumstances and has been made to solve the problems of the above-described conventional example. When the zoom lens reaches the zooming end, the zoom driving mechanism is reversely driven by a predetermined amount. As a result, the tilt of the zoom lens is eliminated. The purpose is to propose an image projection device.

"Means for Solving Problems" The technical means of the present invention for achieving this object are as follows.

This image projection device is for enlarging and projecting an image of an original document illuminated by light from a light source, and a zoom lens for zooming between both zooming ends of the maximum magnification and the minimum magnification, and a zoom lens drive And a mechanism.

When the zooming mechanism reaches at least one of the zooming ends due to zooming, the zoom driving mechanism is reversely driven in the direction opposite to the zooming direction, which is the amount necessary to eliminate the tilt of the zoom lens from the normal posture due to the stop. It is supposed to be.

"Operation" Since the image projection apparatus according to the present invention comprises such means, it operates as follows.

The light from the light source illuminates a document such as a microfilm, and the image of the document is enlarged and projected on an image receiver by a zoom lens or the like.

Then, zooming by the zoom lens is performed as follows.

That is, when the zoom lens reaches a predetermined zoom end due to zooming, the zoom drive mechanism is driven in the reverse direction by a predetermined amount.

Here, due to the urging force associated with the stop, the zoom gear or the like rotated to transmit the drive from the zoom drive mechanism tends to twist and the zoom lens also tends to tilt. However, by driving the zoom drive mechanism in the reverse direction, such a twist is surely corrected, and the tilt is surely eliminated.

In this way, the zoom lens can easily and easily maintain its normal posture.

[Examples] The present invention will be described in detail below based on the examples shown in the drawings.

First of all, regarding the configuration, reader printer overview, projection lens, lens box, overview of each drive mechanism, operation panel, control by magnification instruction means, zoom lens and zoom drive mechanism, specific control example, related control, C lens drive The mechanism will be described in order.

An outline of a reader printer, which is an example of an image projection device,
It is as follows.

FIG. 8 is a perspective view of an optical system of the example, and FIG. 9 is a front view of the same.

The light from the light source such as the exposure lamp 1 is condensed by the condenser lens 2.
Then, the light is condensed by the fixed condenser lens 3, and the original such as the microfilm 4 is irradiated from below and passes through to reach the projection lens 5. Therefore, the image on the microfilm 4 is enlarged and projected by the projection lens 5.

Then, in the reader mode, the image from the projection lens 5 is bent by the reader first mirror 6 and the fixed reader second mirror 7 at the reader position, and enlarged on the screen 8 which is an image receiver arranged on the upper front surface of the main body. Projected. During this time, the first print mirror 9 moves to the retracted position on the right side of the drawing and assumes a folding posture, and the third print mirror 10 also moves to the retracted position on the front side of the drawing to retract outside the formed optical path of the leader. ing.

Next, in the print mode, first the leader first mirror 6 moves upward from the leader position and retracts outside the formed printer optical path. Print on behalf of the first mirror 9
And the print third mirror 10 are synchronously moved from the retracted position to the left and rear scanning start positions in the drawing, respectively, and then are moved to the right and front scanning end positions from the respective scanning start positions. To do. In this way, the image from the projection lens 5 is bent by the print first mirror 9, the fixed print second mirror 11, the print third mirror 10, and the fixed print fourth mirror 12 to form a slit (not shown). Through the projection) onto the surface of the photoconductor 13 which is a rotary drum image receptor. Then, an image is formed by a known process and is copied on the copy paper 14.

In the figure, reference numeral 15 is a roll film carrier in which the microfilm 4 is loaded, 16 is a reflection mirror arranged behind the exposure lamp 1, and 17 is a mirror for bending light upward.

The reader printer is like this.

Next, the projection lens 5 and the like will be described.

FIG. 1 shows a projection lens 5 and a lens box described later,
It is a perspective explanatory view showing each drive mechanism.

The type of the projection lens 5 is divided into a single lens 18 and a zoom lens 19, and either one is selectively used.

First, the desired single lens 18 is selected and used from a plurality of single lenses having different magnifications. The single lens 18 is held in the lens barrel 20, which is a handle plate.
It is loosely inserted and held in the opening 22 of 21. Further, a focus gear 23 is attached to the outer periphery of the lens barrel 20 so as to be independently rotatable, and a helicoid screw or the like is provided so that the single lens 18 can be vertically moved by the rotation of the focus gear 23.

Similarly, the zoom lens 19 is also held in the lens barrel 24, and the lens barrel 24 is loosely inserted and held in the opening 26 of the handle plate 25. A focus gear 27 is attached to the outer circumference of the lens barrel 24 so as to be independently rotatable.
Is attached, and a cam ring, a pin, and the like are attached so that the zoom lens 19 can be moved up and down by the rotation of the focus gear 27. Further, a zoom gear 28 is attached to the outer periphery of the lens barrel 24 so as to be independently rotatable, and the distance between the lens balls in the zoom lens 19 is changed by the rotation of the zoom gear 28.
It is supposed to be used for zooming. The zoom gear 28 is not rotatable endlessly, but is configured to stop at a position corresponding to the maximum magnification and the minimum magnification of the zoom lens 19 and not rotate further or more. A bent portion 29 for detection, which will be described later, is provided upright at the right corner of the handle plate 25 in the figure.

30 is a prism, and this prism 30 is an optical
It is for image rotation, that is, for rotating the projected image and appropriately adjusting the orientation of the image. And this prism 30 is held in the lens barrel 31,
A prism gear 32 is rotatably attached to the outer periphery of the prism gear 32, and the prism 30 is internally rotated by the prism gear 32. In use, the lens barrel 31 of the prism 30 is fitted and seated on the lens barrel 20 or 24 of the single lens 18 or the zoom lens 19 which is the projection lens 5.

The projection lens 5 and the like are configured in this way.

Next, the lens box 33 and the like will be described.

The lens box 33 has a box shape, and is attached and fixed to an intermediate base 34 of a device body such as a reader printer.
Then, in the lens box 33, the selected single lens 18 or zoom lens 19 which is the projection lens 5 is set. That is, the handle plate 21 or 25 is inserted and placed in the lens box 33, and the single lens 18 or the zoom lens 19 is attached.
Is a notch formed in the center of the bottom plate of the lens box 33.
Positioned at 35.

In the lower left and right corners of the lens box 33, the zoom lens 19
A detection means 36 for setting that is set is provided. As the detection means 36, for example, a photo sensor is used in the illustrated example, and the positional relationship is such that the bent portion 29 of the handle plate 25 of the set zoom lens 19 is inserted between the light emitting portion and the light receiving portion. Is set. Folding part 29
By the light shielding by, the set of the zoom lens 19 is detected.

Further, in the illustrated zoom lens 19, a bent portion 29 is formed at the right corner of the handle plate 25 in the figure, and this is detected by the detection means 36 arranged at the right corner of the lens box 33 in the figure. ing. Therefore, in another zoom lens 19 different in magnification and the like from this zoom lens 19, a bent portion is formed in the left corner of the handle plate 25, and this is detected at the left corner in the figure of the lens box 33. Zoom lens by detecting by means 36
Not only is it possible to detect 19 sets, but it is also possible to determine the type of zoom lens 19 that has been set.
Further, by changing the shape, position, etc. of the bent portion 29 and the like and disposing the detecting means 36 correspondingly, it is possible to discriminate between the three or more types of zoom lenses 19.

The lens box 33 and the like have such a configuration.

Next, the outline of each drive mechanism will be described.

First, the zoom drive mechanism 37 is as follows. That is, the zoom drive mechanism 37 includes a pulse motor, which is a zoom motor 38 provided in the stationary portion of the main body, and a torque limiter whose input side is connected to the rotation shaft of the zoom motor 38.
39, a timing pulley 40 connected to the output side of the torque limiter 39, and an endless timing belt 42 stretched between the timing pulley 40 and another timing pulley 41 in order to interlock with each other. The drive shaft 43 has the timing pulley 41 fixed to one end. The drive shaft 43 is inserted and held in the lens box 33 via a bearing (not shown) provided in the intermediate base 34, and the other end is in a bearing 44 provided on the bottom plate of the lens box 33. Supported and lens box 33
A drive gear 45 is fixedly provided therein. In this way, the drive of the zoom motor 38 is transmitted to the drive gear 45. The zoom gear 28 of the zoom lens 19 set in the lens box 33 is positioned so as to mesh with the drive gear 45. The zoom drive mechanism 37 has such a structure.

Next, the focus drive mechanism 46 is the zoom drive mechanism 37 described above.
It is configured according to. That is, the focus drive mechanism 46 includes a pulse motor, which is a focus motor 47 provided in a stationary portion of the main body, a timing pulley 49 connected to the focus motor 47 via a torque limiter 48, and a timing belt connected to the timing pulley 49.
It has a timing pulley 51 which is interlocked by 50 and a drive shaft 52 which is fixed to one end of the timing pulley 51. The drive shaft 52 is pierced and held in the lens box 33 via a bearing (not shown), and the other end is supported by a bearing 53 provided on the bottom plate of the lens box 33. A drive gear 54 is fixedly provided in the 33. In this way, the drive of the focusing motor 47 is transmitted to the drive gear 54. The focus gear 23 or 27 of the single lens 18 or the zoom lens 19 that is the projection lens 5 set in the lens box 33 is
The drive gear 54 is positioned so as to mesh with it. The focus drive mechanism 46 has such a structure.

The prism drive mechanism 55 is configured according to the zoom drive mechanism 37 and the focus drive mechanism 46 described above. That is, the same prism motor as described above (not shown), the timing belt 56, and the timing pulley 5
It has a drive shaft 58, a bearing 59, a drive gear 60 and the like. The prism gear 32 of the prism 30 set together with the projection lens 5 in the lens box 33 is positioned so as to mesh with the drive gear 60. The prism drive mechanism 55 has such a structure.

The outline of each drive mechanism is as described above.

Next, the operation panel will be described.

FIG. 2 shows an operation panel provided on the front side of the reader printer.

In the figure, 61 is a zoom key, 62 is an image rotation key, and 63 is a focus key. Each of the zoom key 61, the image rotation key 62, and the focus key 63 is a seesaw key that can be pressed in both the left and right directions, and is a two-stage key that can be switched in both directions, and is provided opposite each other. The switch is also a two-stage switch.

Therefore, when the zoom key 61 is pressed to the right, the zoom signals to the high-magnification side, and to the left, the zoom signals to the low-magnification side are lightly pressed to serve as low-speed signals for fine adjustment, and strongly pressed to feed the zoom signals. The signals are output as high-speed signals and are input to the control means such as the microcomputer 65 via the port 64 as shown in FIG. Then, from the microcomputer 65, the corresponding drive signal is sent to the port 6
4, output to the zoom motor 38 of the zoom drive mechanism 37 via the drive circuit 66. Accordingly, the zoom drive mechanism 37 is driven, and the zoom lens 19 performs corresponding zooming.

Similarly, pressing the focus key 63 to the right or left outputs focus signals in both directions, a light press to output as a low-speed signal for fine adjustment, and a hard press to output as a high-speed signal to feed, respectively. Input to the microcomputer 65. And a microcomputer
From 65, a corresponding drive signal is output to the focus motor 47 of the focus drive mechanism 46, and accordingly the projection lens 5
Therefore, the corresponding focus is made.

The operation of the image rotation key 62 is also the same. 67 is a print key, 68 is a numeric keypad, 69 is a lamp key for turning on and off the exposure lamp 1, and 70 is a clear key.

The operation panel is like this.

Next, the control by the magnification instruction means will be described.

First, as the magnification instructing means for the single lens 18 which is the projection lens 5, the one shown in FIG. 3 is used in this embodiment. That is, a magnification instruction key 72 is provided on the peripheral frame 71 of the screen 8 of the reader printer, and when the magnification instruction key 72 is pressed, the magnification instruction sections A, B, C and D, which are light emitting diodes for instructing each magnification, are sequentially arranged. Flashes everywhere. That is, the operator turns on the corresponding magnification instruction section A, B, C or D by pressing the magnification instruction key 72 for the single lens 18 having the desired magnification set in the lens box 33. Then, the magnification signal corresponding to the illuminated magnification instruction section A, B, C or D is input to the control means such as the microcomputer 65 as shown in FIG.

The magnification instructing means for the single lens 18 is not limited to the manual input method shown in FIG. 3, but may be the automatic detection method shown in FIG. 4, for example. That is, each the rear end of the handle plate 21 of the single lens 18, the protruding portion 73 ₁ was different in position by the magnification of the single lens 18, 73 ₂ are formed, the projecting portions 73 _1, 73 ₂ is a single When the lens 18 is set in the lens box 33, the position and size are set so as to be projected rearward from the opening 74 formed in the back plate of the lens box 33. Therefore, the corresponding micro switches 75 to the rear
₁ and 75 ₂ are arranged, and the protruding portion 73 ₁ or 73 _{2 of} the set single lens 18 is detected by the microswitch 75 ₁ or 75 ₂ , and the corresponding magnification signal is output to the microcomputer.
It will be input to 65 mag. Although FIG. 4 shows two types of magnifications, it is of course possible to use three or more types of magnifications. The other reference numerals in FIG. 4 are the same as those in FIG.

On the other hand, the magnification instruction means of the zoom lens 19, which is the projection lens 5, is as follows. The magnification instructing means of the zoom lens 19 may be of a manual input type according to the description of the single lens 18 described above, but in this embodiment, an automatic detection type is used. That is,
By depressing the zoom key 61, the zoom motor 38 of the zoom drive mechanism 37 is driven, so that the zoom lens 19 is zoomed from a reference magnification described later to a desired magnification. Therefore, by counting the number of drive pulses during pressing ON / OFF of the zoom key 61, that is, during driving ON / OFF of the zoom motor 38, a corresponding magnification signal is input to the microcomputer 65 or the like.

The magnification instructing means for the single lens 18 and the zoom lens 19 is as described above. Then, the magnification is set based on the magnification instruction, and the following control is performed.

That is, when such a magnification signal is input to the microcomputer 65 or the like to set a magnification, first, the position corresponding to this magnification set is set for the condenser lens 2, and the moving direction and the moving amount to the position are set. Is calculated, and the corresponding drive signal is the C of the C lens drive mechanism.
It is output to the lens motor (described later).

Secondly, the speed for fine adjustment in the focus of the projection lens 5 is controlled. That is, since the depth of focus differs for each magnification, the driving speed of the focus driving mechanism 46 suitable for focusing, that is, the rotation speed of the focusing motor 47 also differs. Therefore, corresponding to the magnification setting, the rotational speed is calculated such that the higher the magnification is, the higher the magnification is, and the higher the magnification is, the slower the rotation speed is set.

It should be noted that a constant relational expression holds between the magnification of the projection lens 5, that is, the depth of focus, and the drive speed of the focus drive mechanism 46 suitable for this, and the calculation is performed as described above. Although this relational expression is established without any individual difference, the driving speed more suitable for each person varies proportionally due to the difference in individual sense when viewed for each magnification and depth of focus.
Therefore, based on the above relational expression, it is preferable that the entire level of the driving speed can be adjusted faster or slower.

The control by the magnification instruction means is performed in this way.

Next, the zoom lens 19 and the zoom drive mechanism 37 will be described in detail.

The zoom lens 19 is supposed to be zoomed to a certain reference magnification, which is a reference for subsequent zooming and the like, by driving the zoom drive mechanism 37 based on the set detection of the detection means 36. If the zoom lens 19 does not have an endless zoom mechanism, that is, if zooming is performed between the maximum and minimum zoom ends, the reference magnification is set to one of these zoom ends. To be done.

Further, the zoom drive mechanism 37 is an amount necessary to eliminate the tilt of the zoom lens 19 from the posture at all times when the zooming end reaches at least one of the zooming ends due to zooming, and reverse rotation in the direction opposite to that during zooming. Driven.

The zoom lens 19 and the zoom drive mechanism 37 are configured as described above.

Next, a specific control example will be described with reference to FIG.

θ is the maximum rotation angle of the zoom gear 28, which corresponds to the maximum zoom range between the maximum magnification and the minimum magnification of the zoom lens 19. The maximum rotation angle θ is set to the maximum value among a plurality of zoom lenses 19 having different magnifications and the like, and the detection unit 36 determines the type of each zoom lens 19. If the zoom lens 19 has been selected, it may be set to the one of the determined zoom lens 19. φ is a target rotation angle of the zoom gear 28, which is set to be slightly larger than the maximum rotation angle θ. φ ′ is the actual rotation angle of the corresponding zoom gear 28 starting from the set magnification of the zoom lens 19 to the reference magnification. The reference magnification is set to the minimum magnification.

The set detection signal of the zoom lens 19 by the detection means 36 is
As shown in FIG. 10, a drive signal input to the microcomputer 65 to rotate the zoom gear 28 in the direction of the reference magnification by the target rotation angle φ is applied to the zoom motor 38 of the zoom drive mechanism 37.
Is output to. Then, the zoom gear 28 starts to rotate by the target rotation angle φ from the position corresponding to the magnification at the time of setting, but stops at the position corresponding to the reference magnification on the way, and the zoom lens 28
19 is surely zoomed to the standard magnification.

Since the actual rotation angle φ ′ of this zoom gear 28 is smaller than the target rotation angle φ, the zoom motor 28 that has been stopped is applied with a biasing force to further rotate it in the zooming direction by the zoom motor 38. Therefore, the zoom gear 28 and the drive gear 45 that meshes with the zoom gear 28 are likely to twist, and the zoom lens 19 also includes the micro film 4 and the roll film carrier.
Attempts to lean from a constant posture facing the glass surface of 15.

Now, when a predetermined load is reached, the drive amount of the zoom motor 38 corresponding to the difference between the target rotation angle φ of the zoom gear 28 and the actual rotation angle φ ′ is absorbed by the torque limiter 39. At the same time, the zoom motor 38 is driven in the reverse direction by a predetermined amount required to eliminate the twist of the zoom gear 28 and the like, and the tilt of the zoom lens 19, so that the zoom gear 28 is also rotated by the necessary angle in the reverse direction, so that the zoom lens 19 also keeps its normal posture. Will be maintained.

Regarding the stop of the zoom gear 28, the detection means is provided on the lowest magnification side which is the reference magnification, and the zoom motor started at the target rotation angle φ based on the detection signal of the detection means is not described above. Immediately stop driving 38 itself,
Therefore, a method of stopping the rotation of the zoom gear 28 is also possible. And even under such a method, the problem of twisting of the zoom gear 28 and drive gear 45 and tilting of the zoom lens 19 occurs based on the urging force that attempts to rotate in the zooming direction so far, in accordance with the above. To do. Therefore, in the same manner as described above, the predetermined amount of zoom motor 38 required for eliminating these is driven in reverse.

The specific control of FIG. 5 is performed in this way.

Next, related control will be described.

The reference magnification serves as a reference for the subsequent zooming, and further control of the movement of the condenser lens 2 and the speed for fine adjustment in the focus of the projection lens 5 as described above. That is, since the posterior zoom lens 19 is zoomed to this reference magnification or the desired magnification, the magnification of the zoom lens 19 is determined and set by the driving amount of the zoom motor 38 during that time. In the present embodiment in which a pulse motor is used as the zoom motor 38,
Magnification is set by counting the number of drive pulses, or by counting the number of pulses of the encoder attached to synchronize when other DC motors are used. Based on the above, the condenser lens 2 is moved as described above, and the speed for fine adjustment of the focus of the projection lens 5 is set.

Also, since the maximum rotation angle θ of the zoom gear 28 is given,
The zoom motor should be stopped so that the rotation of the zoom gear 28 is surely stopped on the other zoom end side, that is, just before the maximum magnification.
38 is controlled. Note that, regardless of such control, detection means is provided on the other side of the maximum magnification, which is the zooming end side, and the drive of the zoom motor 38, that is, the rotation of the zoom gear 28 is stopped based on the detection signal of the detection means. After that, the zoom motor 38 may be controlled so that the necessary amount of reverse rotation is driven as described above.

Further, in the present embodiment, a pulse motor is used as the zoom motor 38 of the zoom drive mechanism 37, and the torque limiter 39 is also used, but when another DC motor is used as the zoom motor 38, Zooming to the standard magnification is performed as described below, regardless of the above. That is, while zooming the zoom lens 19 from the set magnification to the reference magnification side, the rotation speed of the encoder attached to synchronize with the DC motor that is the zoom motor 38 is monitored to reach the variable magnification end that is the reference magnification. The load on the zoom motor 38 slows down the rotation speed of the encoder, and the DC motor, which is the zoom motor 38, is stopped by the detection.

Note that when a pulse motor is used as the zoom motor 38 as in the present embodiment, the torque is relatively weak, so it is necessary to make the torque limiter 39 function with a smaller torque that causes step out. Will be strict.

The controls related to the zoom lens 19 and the zoom drive mechanism 37 are
This is done in this way.

Next, the C lens driving mechanism 76 will be described.

FIG. 6 is a plan view of the C lens driving mechanism 76, and FIG. 7 is a front view of the same. The C lens driving mechanism 76 is of a system in which the condenser lens 2 is moved to change its relative position to the light source such as the exposure lamp 1. A method of moving the exposure lamp 1 side is also possible.

The C lens drive mechanism 76 is a C motor such as a pulse motor.
It has a lens motor 77, a pinion gear 79 mounted on a motor shaft 78 thereof, and a rack 80 that meshes with the pinion gear 79. The rack 80 is fixed to a holder 81 holding the condenser lens 2 via a support member 82. Further, one side of the holder 81 is slidably supported by a slide bearing 83 on a corresponding operation shaft 84 via a support member 82. The other side of the holder 81 is allowed to travel on the plane of the main body immovable portion by the runner 86 via the support member 85.

Therefore, the condenser lens 2 held by the holder 81 is driven by a predetermined amount of forward and reverse rotation of the C lens motor 77.
Is moved forward and backward by a predetermined distance.

The C lens drive mechanism 76 has such a structure.

The above is the description of the configuration and the like.

Next, the operation and the like will be described.

FIG. 11 and FIG. 12 are flowcharts showing the control of the embodiment, FIG. 11 shows the basic control, and FIG. 12 each shows its subroutine. The operation and the like will be described below with reference to these drawings.

First, the operator operates the projection lens 5 or the desired single lens 18
Alternatively, the zoom lens 19 is set in the lens box 33 of the main body of the reader printer.

Then, in step, after setting the reference position of the condenser lens 2 and other necessary initial settings, it is determined in step that the print key 67 is on. If it is on, the print mode is set in step, and after the printing operation is performed, the process returns. If the print key 67 is off in step, the reader mode is maintained, and the process proceeds to step to determine whether the detecting means 36 of the zoom lens 19 is on. In the illustrated example, whether or not the zoom lens 19 is set is determined by whether or not the bent portion 29 of the handle plate 21 shields the light between the light emitting portion and the light receiving portion of the photo sensor serving as the detecting means 36.

When it is determined whether the type of the projection lens 5 set in this way is the single lens 18 or the zoom lens 19, and the detection unit 36 is not on but the single lens 18, the step ,,
Go to. That is, in steps, ..., The magnification of the single lens 18 is discriminated by observing the magnification signal corresponding to the magnification instruction sections A, B, ... , ... are used to set the corresponding magnification. In this step, ... Magnification set, the optimum position of the condenser lens 2 is set for each magnification, the distance a from the reference position to the optimum position, and the C lens motor 77 corresponding to the distance a.
The number of pulses to the barrel pulse motor is set and stored.

If the type of the projection lens 5 that is set is determined to be the zoom lens 19 by turning on the detection means 36 in step, the process proceeds to zoom 1 in step. FIG. 12 (1) shows this zoom 1 routine.

In the zoom 1 routine, the zoom lens
The zoom motor 38 of the zoom drive mechanism 37 is driven to rotate the zoom gear 28 of 19 to the target rotation angle φ in the direction of the reference magnification, but the zoom gear 28 actually rotates from the position corresponding to the magnification at the time of setting by the rotation angle φ ′. Then, the zoom lens 19 is zoomed to the standard magnification.

Here, the zoom gear 28 and the drive gear 45 are likely to twist,
The zoom lens 19 always tries to tilt from the posture. here,
While the torque limiter 39 functions, the zoom motor 38 is reversely driven by two pulses in the next step, and the zoom gear 28 is also rotated by the required angle in the opposite direction to the conventional zooming direction, so that the twisting, tilting, etc. are prevented. As a result, the zoom lens 19 can be accurately floated on the glass surface of the roll film carrier 15.

Further, as described above, even if the zoom lens 19 is set at any magnification, the zoom lens 19 is first zoomed to the reference magnification, which is a reference thereafter, so that the operability at the time of setting is significantly improved.

Next, in step, ..., Whether the type of the zoom lens 19 is 1 or 2, etc. is discriminated by the detection means 36, and in the corresponding step, ..., The movement amount of the condenser lens 2 corresponding to each type of zoom lens 19. The coefficient is calculated, and the reference magnification of each is set in steps, .... Along with the magnification setting, the distance a from the reference position to the optimum position for the magnification of the condenser lens 2 and the corresponding number of pulses to the C lens motor 77 are set in the same manner as in the single lens 18 described above.

The zoom 1 routine of FIG. 12 (1) is as described above.

The flow returns to FIG. 1, and the condenser lens 2 is moved in steps. FIG. 12 (2) shows the movement routine of the condenser lens 2. First, in step, the moving direction and the moving amount of the condenser lens corresponding to each magnification set up to now are calculated. That is,
In the case of the single lens 18, the magnification is set in the above steps, ... In the case of the zoom lens, the magnification is set in the above steps, ... The distance b from the reference position is stored, and the distance a from the reference position set and stored for the magnification set from the distance b is subtracted. The positive / negative of this subtraction value determines the forward / reverse rotation direction of the pulse motor that is the C lens motor 77, that is, the moving direction of the condenser lens 2, and the value determines the number of pulses to the C lens motor 77, that is, the movement of the condenser lens 2. The quantity is determined. Zoom lens 19
In this case, the calculation is performed based on the moving amount coefficient in the above step.

Then, the C lens motor 77 is turned on in the step, and when the required amount of movement of the condenser lens 2 as calculated, that is, the rotation of the C lens motor 77 is confirmed in the step, the C lens motor 77 is driven in the step. Is turned off. In this way, the condenser lens 2 is moved to the position corresponding to each magnification set. Therefore, on the image receiving surface of the screen 8, the photoconductor 13 or the like, which is the effective image area,
The illuminance distribution and the illuminance are appropriately adjusted, the uneven illuminance and the decrease in illuminance are eliminated, and a high-quality image is always obtained.

The movement routine of the condenser lens 2 in FIG. 12 (2) is as described above.

Now, the flow returns to FIG. 11, and in step the zoom key 61
Is determined to be on, and if it is on, step zoom 2
Proceed to routine. FIG. 12 (3) shows this zoom 2 routine.

In other words, the zoom key 61
For example, it is determined whether or not the pressed state is rightward. Then, in step, the direction flag is set or reset corresponding to the direction, and in step the zoom drive mechanism 37
The pulse motor, which is the zoom motor 38, starts driving in that direction, the zoom key 61 is turned off in step, and the driving is stopped in step
The number of drive pulses of is counted. When the zoom key 61 is turned off and released in step, the flow returns to FIG.

In this way, the operator zooms the zoom lens 19 to a desired magnification.

The zoom 2 routine in FIG. 12 (3) is as described above.

Now, returning to FIG. 11, the flow sets the magnification of the zoom lens 19 when the zoom key 61 is turned off in the above step. And the above steps,
.. and step ,, the distance a from the reference position to the position suitable for the magnification of the condenser lens 2 and the corresponding pulse number to the C lens motor 77 are set and stored.

Then, the flow returns to the above-mentioned step, that is, the routine for moving the condenser lens 2 in FIG. 12 (2), and thereafter, the above-described steps are repeated.

When the zoom key 61 is turned off and released in step, the process proceeds to step and the state of the focus key 63 is determined. Then, if the focus key 63 is not pressed and is off, the flow returns to the step, and the above is repeated thereafter.

When the focus key 63 is pressed and turned on in step, the process proceeds to focus in step. 12th
The figure (4) shows this focus routine.

That is, in the focus routine, first in step, the drive speed of the focus drive mechanism 46 corresponding to the set magnification of the projection lens 5 is calculated. That is, in the case of the single lens 18, the set magnification in steps, ... Is set, and in the case of the zoom lens 19, the set magnification in steps or the set magnification in steps ,. . Therefore, based on this, at least the rotation speed of the focusing motor 47 for fine adjustment in focusing, and the frequency of the pulse given in the case of a pulse motor are calculated.

Then, in the next step, it is determined whether or not the pressed state of the focus key 63, which is a seesaw key, is in the right direction, for example. Then, in step, the direction flag is set or reset corresponding to that direction, and in step, the focusing motor 47 of the focus drive mechanism 46 moves in that direction in step, at the speed given in step. It is driven until the key 63 is turned off and stopped in steps.

In this way, the fine adjustment of the focus is performed in accordance with the magnification when the magnification is low and the depth of focus is large, and when the magnification is high and the depth of focus is small, it is slow. Accordingly, the focus speed at the time of fine adjustment, that is, the moving speed of the projection lens 5 becomes appropriate, and the focus becomes smooth and easy.

The flow returns to FIG. 1 when the focusing motor 47 is stopped and turned off in step.

The focus routine of FIG. 12 (4) is as described above.

Then, the flow returns to the step in FIG. 11 and the above-mentioned steps are repeated thereafter.

The above is the description of the operation and the like.

[Advantages of the Invention] As described above, the image projection device according to the present invention is capable of driving a zoom gear such as a twisted zoom lens by reversely driving the zoom drive mechanism by a predetermined amount when the zoom lens reaches the zooming end. The tilt is definitely eliminated. As a result, the zoom lens is always kept in a good posture, and the operability is improved with good usability and appearance, and the retaining mechanism sagging ring, pins are damaged, and the zoom gear that transmits the drive from the zoom drive mechanism and its drive gear are damaged. The effect that the conventional examples of this kind have been eliminated is remarkably large.

[Brief description of drawings]

FIG. 1 shows an embodiment of an image projection apparatus according to the present invention,
It is a perspective explanatory view of a main part. FIG. 2 is a front view of the operation panel. 3 and 4 each show an example of a single lens magnification instruction means,
FIG. 3 is a front view of a magnification instruction key or the like by a manual input method, and FIG. 4 is a perspective explanatory view of a protrusion, a micro switch, etc. by an automatic detection method. FIG. 5 is an explanatory diagram showing a specific control example of the zoom lens and the like. 6 and 7 show C lens driving, FIG. 6 is a plan view thereof, and FIG. 7 is a front view thereof. 8 and 9 show a reader printer, FIG. 8 is a perspective view of the optical system thereof, and FIG. 9 is a front view thereof. FIG. 10 is a block diagram showing the control means according to the above embodiment. FIG. 11 and FIG. 12 are flowcharts of the control according to the above embodiment, FIG. 11 shows the basic control, FIG. 12 shows each routine thereof, and FIG. FIG. 2 (2) shows a condenser lens moving routine, FIG. 3 (3) shows a zoom 2 routine, and FIG. 4 (4) shows a focus routine. 1 ... exposure lamp (light source) 4 ... micro film (original) 19 ... zoom lens 37 ... zoom drive mechanism

Claims (1)

[Claims] 1. An image of a document illuminated with light from a light source,
An image projection apparatus for magnifying and projecting, comprising: a zoom lens that performs zooming between both zooming ends of the maximum magnification and the minimum magnification; and a zoom drive mechanism of the zoom lens, wherein the zoom drive mechanism comprises When at least one of the zooming ends is reached by zooming, the zoom lens is driven in the reverse direction in the direction opposite to that at the time of zooming, which is necessary for eliminating the tilt of the zoom lens from the posture at all times. Image projection device.