JP2584023Y2 - Variable power optical device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a variable power optical apparatus for forming an image of a document in a zoomed state by moving an image forming lens and a mirror along the optical axis, and more particularly, to a single focus lens. By moving the single focus lens and the mirror interposed between the image plane and the mirror along the optical axis direction, the distance from the document surface to the single focus lens and the distance from the single focus lens to the image plane And a variable magnification optical device that changes the ratio of the image formation to the original image by appropriately changing the ratio.

[0002]

2. Description of the Related Art Conventionally, a so-called electronic copying machine that performs copying using an electrophotographic method illuminates a document placed on a document placing portion with a light source such as a fluorescent lamp and illuminates with the light source. The image on the document surface is formed on the photosensitive layer of the photosensitive drum by an imaging optical system including an imaging lens and a mirror. Recently, the image forming lens constituting the image forming optical system is moved in the optical axis direction to move the image forming lens from the document surface to the image forming lens, and from the image forming lens to the image forming surface (that is, the photosensitive layer surface of the photosensitive drum). An imaging optical system is used in which the ratio of the image to the original image is made variable by changing the distance to the original image. Some of such image forming optical systems have a so-called variable magnification function that can copy an image by enlarging or reducing the size of the original (the same size) as the original size.

[0003]

However, in the conventional variable-magnification optical apparatus, the carriage supporting the imaging lens or the reflecting mirror provided between the imaging lens and the photosensitive drum is moved in the optical axis direction. In order to be able to move along the optical axis, a guide shaft extending along the optical axis direction is slidably guided via a bearing.
In particular, since a slide bearing is used for the bearing portion, the cost is increased, and improvement has been demanded.

In a conventional variable magnification optical apparatus, a lens carriage and a mirror carriage respectively supporting an image forming lens and a reflection mirror provided between the image forming lens and the photosensitive drum are arranged along the optical axis direction. The two guide shafts are provided for each of the guides so that the guides can be moved, thereby hindering the cost reduction due to the increase in the number of parts and the provision of the two guide shafts. This space must be ensured, which is a hindrance to downsizing of the apparatus, and improvement has been demanded.

The present invention has been made in view of the above-mentioned circumstances, and a main object of the present invention is to provide a variable power optical device capable of achieving cost reduction.

Another object of the present invention is to provide a variable power optical apparatus which can reduce the size of the entire apparatus.

[0007]

Means for Solving the Problems The above-mentioned problems are solved,
In order to achieve the object, according to the first aspect of the present invention, a variable power optical apparatus according to the first aspect of the present invention is configured to move an image forming lens and a mirror along an optical axis direction, thereby changing a size of a document image. In the variable magnification optical apparatus for forming an image, a bearing part slidably guided in a state of being elastically contacted with a guide shaft extending along the optical axis direction via a torsion coil spring is provided. It is characterized by being integrally mounted on a carriage supporting a lens or a mirror.

[0008] Further, a variable power optical device according to the present invention includes:
According to the second aspect, the single focus lens and the mirror interposed between the single focus lens and the image forming surface are moved along the optical axis direction to move from the document surface to the single focus lens. In a variable power optical device that changes the ratio of the image to the original image by appropriately changing the distance from the single focus lens to the image forming surface, a guide shaft extending along the optical axis direction; A carriage for holding the single focus lens or mirror, and bearing means for slidably guiding the carriage while riding on the guide shaft;
And a pressing means for pressing the bearing means against the guide shaft.

Further, the variable power optical device according to the present invention includes:
According to the fifth aspect, the single focus lens and the mirror interposed between the single focus lens and the image forming surface are moved along the optical axis direction to move from the document surface to the single focus lens. In a variable power optical apparatus in which the ratio of image formation to a document image is variable by appropriately changing the distance from the single focus lens to the image plane, one guide extending along the optical axis direction is used. A shaft, a lens carriage for holding the single focus lens, first bearing means for slidably guiding the lens carriage to the guide shaft, a mirror carriage for holding the mirror, and a guide for the mirror carriage. Second bearing means for slidably guiding the shaft.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of an embodiment of a variable power optical apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 schematically shows the internal structure of an electronic copying apparatus 12 to which the variable power optical apparatus 10 of this embodiment is applied in a front view. The electronic copying apparatus 12 includes a housing 14, a platen glass 16 fixed to an upper surface of the housing 14, and serving as a document mounting table on which the document D is mounted, and a document placed on the platen glass 16. An electronic copying mechanism 18 for executing an electrophotographic process for copying the image of D onto recording paper (not shown), and an optical scanning of the original D, and the reflected light (that is, image light) from the original D is transmitted to the electronic copying mechanism 18. And a scanning optical system 22 for forming an image on the photosensitive layer of the photosensitive drum 20. In this embodiment, since the electronic copying mechanism 18 has a well-known structure and does not constitute any feature of the present invention, only the photosensitive drum 20 is shown in the drawing, and the structure is illustrated and described in detail. Is omitted.

In this embodiment, the scanning optical system 22 includes a lamp 24 for illuminating the lower surface (original surface) of the original D on the platen glass 16 over the entire area in the width direction, and the lamp 24. A first reflection mirror 26 for reflecting the light (that is, image light) emitted from the document 24 and reflected by the original D and guiding the light to the left in the drawing, and a light reflected from the first reflection mirror 26 ( A second reflecting mirror 28 for temporarily reflecting the image light) downward, and a third reflecting mirror 28 for further reflecting the reflected light (image light) from the second reflecting mirror 28 and guiding it to the right in the drawing. And a reflection mirror 30 for receiving the image light from the third reflection mirror 30 and forming an image on the photosensitive layer, which is an image forming surface, in a scaled state. And a magnification optical device 10.

The lamp 24 and the first reflecting mirror 26 described above are mounted on a full-speed unit 32 driven to travel leftward in the figure from the position shown in the drawing, while the second and third reflecting mirrors are mounted. Reference numerals 28 and 30 are mounted on a half-speed unit 34 that is driven to travel leftward in the figure at half the speed of the full-speed unit 32 from the illustrated position. Since such a scanning structure is well known and does not constitute any feature of the present invention, a detailed description thereof will be omitted.

Here, the variable power optical device 10 which is a feature of the present invention is shown in FIG. 2 and FIG. 3 schematically showing its plan shape and side sectional shape, respectively. Has a single focus lens 36 as an imaging lens,
The optical distance a from the single focus lens 36 to the document and the optical distance b from the single focus lens 36 to the image forming position are calculated by the formula (1 / a + 1 / b = 1 / f), where f is a single focus lens. (Focal length of 36) is appropriately changed within a range that satisfies the imaging formula expressed by the following formula: so-called mirror magnification. Magnification (b / a) of this magnification optical device 10
In this embodiment, by employing the following configuration, 2.05 times (enlarged) to 1.00 (actual size)
It is set so that it can be arbitrarily changed by 0.48 times (reduction).

As shown in FIGS. 2 and 3, the variable power optical device 10 is provided with a base plate 38 as a device main body in a state where the variable power optical device 10 is mounted and fixed in the above-described housing 14. As shown in the plan view, an opening 40 penetrating in the thickness direction is provided on the right side in the figure. On the upper surface of the base plate 38, a lens carriage 42 for holding the above-described single focus lens 36 so that its optical axis coincides with the above-mentioned optical axis of the image light, and the image light emitted from the single focus lens 36 And a mirror carriage 48 that holds a pair of movable reflecting mirrors 44 and 46 that sequentially reflect the light, are arranged so as to be movable along the optical axis direction.

The mirror carriage 48 projects above and below the base plate 38 while penetrating the above-described opening 40, and is disposed so as to be movable within a range where the opening 40 is formed. That is, although the manner of attachment will be described later, the movable reflection mirror 44 is positioned above the base plate 38 and the movable reflection mirror 46
Are mounted on the mirror carriage 48 in a state of being located below the base plate 38. That is,
The upper movable reflection mirror 44 reflects the image light emitted from the single focus lens 36 downward, and the lower movable reflection mirror 46 converts the image light reflected by the upper movable reflection mirror 44 to the left in the figure. Each attachment state is set so as to reflect toward. On the lower surface of the base plate 38, image light sequentially reflected by the pair of movable reflecting mirrors 44 and 46 is finally reflected toward a predetermined position on the photosensitive layer as an image forming position. Fixed reflection mirror 50
(Shown in FIG. 1) are provided.

On the other hand, as is apparent from FIG. 2, the above-mentioned lens carriage 42 and mirror carriage 48 extend on the above-mentioned base plate 38 along the optical axis direction.
, A guide shaft 52 having a circular cross section is attached. A bearing 54 is integrally attached to one end of the lens carriage 42 to slidably fit the guide shaft 52 and guide the guide shaft 52 to move along the optical axis direction. Also,
At one end of the mirror carriage 48, a bearing portion 56 which is slidably fitted to the guide shaft 52 and guides the guide shaft 52 to move along the optical axis direction is integrally attached.

In this manner, the single focus lens 36 and the two movable reflecting mirrors 44 and 46 are slidably guided by the lens carriage 42 and the mirror carriage 48 holding the respective lenses via the guide shaft 52. The movable state can be achieved along the optical axis direction.
In addition, about these bearing parts 54 and 56, the structure and the axial support state are demonstrated in detail later.

As shown in FIG. 2, a magnification control mechanism 58 is provided between the lens carriage 42 and the mirror carriage 48 while being positioned on the base plate 38. The magnification control mechanism 58 appropriately drives the positions of the lens carriage 42 and the mirror carriage 48 along the optical axis direction based on a magnification signal indicating a magnification from a control unit (not shown). Is achieved. Therefore, this variable power control mechanism 5
Reference numeral 8 denotes a reversible drive motor 6 as a single drive source.
0, a first driving force transmitting mechanism 62 for transmitting the rotational driving force of the driving motor 60 to the lens carriage 42 as a linear driving force, and transmitting the rotational driving force of the driving motor 60 to the mirror carriage 48 as a linear driving force. And a second driving force transmission mechanism 64.

The structure of the first and second driving force transmitting mechanisms 62 and 64 will be described below. Note that the state shown in FIG. 2 shows a state in which the magnification ratio is the same magnification. When the magnification is enlarged, the lens carriage 42 (the single focus lens 36) moves from the same magnification state in the direction of the arrow X (see FIG. 2). That is, it is moved (to the left in the figure), and in the case of reduction, it is moved in the opposite direction.

First, the above-described drive motor 60 has a drive gear 66 coaxially on its motor shaft. On the other hand, a gear ring 68 is rotatably supported around a support shaft 70 in a state of being meshed with the drive gear 66. The gear ring 68 is driven by a drive gear 66 in response to activation of the drive motor 60.
Is driven to rotate around the support shaft 70.

Here, as shown in FIG. 5, the first driving force transmission mechanism 62 described above is coaxial with the gear ring 68,
A drive pulley 72 is provided in a state located above the drive pulley. The drive pulley 72 is integrally joined to the gear ring 68, and the shaft 7 is rotated in accordance with the rotation of the gear ring 68.
It is driven to rotate around zero. The first driving force transmission mechanism 62 includes a pair of driven pulleys 74 and 76 positioned at both ends of the guide shaft 52 described above. Between them, a transmission wire 78 is stretched in a substantially figure-eight shape. Both ends of the transmission wire 78 are connected to the lens carriage 42.

Since the first driving force transmission mechanism 62 is configured as described above, the driving pulley 72 is driven to rotate in response to the activation of the driving motor 60, so that the driving pulley 7 is driven.
2 is transmitted to the lens carriage 42 via the transmission wire 78. In this way, the lens carriage 42 is driven to move along the optical axis while being guided by the guide shaft 52. Become.

On the other hand, the above-described second driving force transmission mechanism 64
Is provided with a cam plate 80 for transmitting the driving force of the driving motor 60 to the mirror carriage 48 in a state converted by a predetermined correlation. In other words, the second driving force transmission mechanism 64 moves the mirror carriage 48 to a predetermined correlation with the movement of the lens carriage 42 along the optical axis direction (specifically, a correlation that satisfies the above-described equation). (Relationship) is configured to be driven to move along the optical axis direction.

The cam plate 80 is formed integrally with the inner periphery of the gear ring 68 described above. A cam groove 82 is formed on the lower surface of the cam plate 80. As shown in FIG. 2, a cam follower 86 fixed to one end of a lever 84 is slidably fitted in the cam groove 82. The lever 84 has two long and short arm portions 84a,
84b are formed integrally from a thin plate in an L-shape in a state of being substantially orthogonal. Note that the arm 84a is
It is set shorter than b. The lever 84 thus formed is pivotally supported by the base plate 38 by a support shaft 88 at the intersection of the two arms 84a and 84b. The cam follower 86 slidably fitted in the cam groove 82 of the cam plate 80 is fixed to the tip of the shorter arm portion 84a.

Here, a long hole 90 extending along the longitudinal direction of the long arm portion 84b is formed at the tip of the long arm portion 84b so as to penetrate in the thickness direction. A sliding pin 92 is slidably penetrated in the elongated hole 90. And
The sliding pin 92 is fitted and fixed to a mirror connecting plate 94 integrally connected to the housing 140 of the mirror carriage 48.

When the cam plate 80 is rotated by the activation of the drive motor 60 and the cam follower 86 moves following the cam groove 82, the lever 84 swings around its pivot point (support shaft 88). Then, the swing is caused by the sliding pin 92 fitted in the long hole 90 of the tip of the arm portion 84b.
Is transmitted to the mirror carriage 48, and the mirror carriage 48 is driven to move along the optical axis direction. That is, the rotation of the cam plate 80 drives the mirror carriage 48 to move along the optical axis while maintaining a predetermined correlation with the lens carriage 42.

Here, the center of rotation of the cam groove 82 (support shaft 7)
The distance from the pivot point of the lever 84 to the cam follower 86 (ie, the length of the arm portion 84a) and the distance from the pivot point to the shaft (ie, the arm) (The length of the portion 84b). In other words, even if the displacement of the cam groove 82 is small, the displacement of the mirror carriage 48 can be set large. The movement amount of the mirror carriage 48 with respect to the displacement amount of the cam groove 82 is the ratio of the length of the arm portions 84a and 84b (lever ratio).
Can be arbitrarily set by changing.

In this embodiment, the ratio (lever ratio) between the length of the arm portion 84a and the length of the arm portion 84b is set to approximately 1: 2. Also, the lens carriage 42
As shown in FIG. 6, the shape of the cam groove 82 is set for the relationship between the magnification and the magnification of the mirror carriage 48. In FIG. 6, the vertical axis indicates the magnification, the horizontal axis indicates the amount of movement, the solid line indicates the change in the amount of movement of the lens carriage 42, and the dashed line indicates the change in the amount of movement of the mirror carriage 48. Is shown.

In other words, the shape (trajectory) of the cam groove 82 has a relationship with the lever ratio of the lever 84 described above.
The mirror carriage 48 is set to have a moving amount shown in the figure with respect to the driving of moving the single focus lens 36 by the rotation of the cam plate 80. Therefore, the state shown in FIG.
No matter which direction of reduction, the mirror carriage 4
Numeral 8 moves in a direction away from the single focus lens 36 (although the moving rate is different).

The relationship between the shape of the cam groove 82 of the cam plate 80 and the position of the pivot point of the lever 84 is set as shown in FIGS. 7A to 7C. That is, when the magnification is the same, the displacement of the cam groove 82 from the rotation center is set to be the largest as shown in FIG. 7A. Therefore, the cam groove 82 is closer to the center of rotation (the amount of displacement from the center of rotation is smaller) when moving from the same magnification to either the enlarged side shown in FIG. 7B or the reduced side shown in FIG. 7C. It is set as follows. Note that, in the drawing, reference symbol A indicates the locus of the cam follower 86 along the cam groove 82.

As a result, especially when the magnification changes from the same magnification to the enlargement side (when moving from the state shown in FIG. 7A to the state shown in FIG. 7B), the mirror carriage 48 with respect to the rotation angle of the cam plate 80 is changed. Is large (that is, the contact angle θ of the cam follower 86 with the cam groove 82 is large), so that the mirror carriage 48 requires a force to move. However, in this case, the cam groove 8
Because 2 approaches the center of rotation (the radius of rotation becomes smaller)
Even if the torque for rotating the cam plate 80 is the same, a stronger moving driving force can be obtained.
0 can be set to low output

The fact that the amount of movement of the mirror carriage 48 with respect to the rotation angle of the cam plate 80 is large means that
That is, high-precision movement drive cannot be performed unless the cam groove 82 is set to a high precision. If the cam groove 82 approaches the center of rotation, more precision is required. However, in the case of the optical system of this embodiment, since the depth of focus becomes deeper as the magnification changes toward the enlargement side, the permissible accuracy is widened, and it is not necessary to make the accuracy particularly high.

On the other hand, when the magnification changes from the same magnification to the reduction side, the cam groove must have high precision because the depth of focus becomes shallow. However, since the amount of movement of the mirror carriage 48 with respect to the rotation angle of the cam plate 80 is small (the contact angle θ of the cam follower 86 with the cam groove 82 is small), the permissible accuracy of the cam groove 82 is widened, and both are offset. Therefore, the accuracy does not need to be particularly high.

That is, in this embodiment, the cam groove 8
Reference numeral 2 denotes a shape having almost the same accuracy in both enlargement and reduction directions with a magnification ratio of 1: 1, and more powerful driving in a direction requiring a force for movement.

Incidentally, as shown in FIG.
The image light reflected by the third reflecting mirror 30 mounted on the half-speed unit 34 at a position adjacent to the lens carriage 42 in the same magnification state in the direction indicated by the arrow X above. A shading correction plate 96 is attached to the part where the light enters. As shown in FIG. 8, the shading correction plate 96 has a plate-shaped shading portion 96a that blocks the optical path of image light in a predetermined shape.
And a tongue-shaped operating portion 96b extending at right angles to the lower ends of both ends of the shading portion 96a, and a shaft portion 96c formed to protrude laterally from the intersection of the shading portion 96a and the operating portion 96b. Are rotatably fitted to the base plate 38. The shading correction plate 96 is provided to correct the characteristic characteristic of the single focus lens 36 that the peripheral light amount increases when the magnification is equal to or less than 1: 1.

That is, when the single focus lens 36 (that is, the lens carriage 42) moves from the equal magnification position to the reduction side, the lens carriage 42 rotates so as to be raised by being kicked by the operation unit 96b, and the shading unit 96a Is raised so that the light path of the image light can be blocked in a predetermined shape to correct the light amount. On the other hand, when the magnification is on the enlargement side from the unity-magnification position and it is not necessary to correct the light amount, the shading portion 96a is kicked by the lens carriage 42 moving to the enlargement side and falls on the base plate 38, It is set so as not to block the optical path of the image light at all.

A light-shielding film 98 having a predetermined width for preventing light leakage is mounted on the end face of the single focus lens 36 (lens carriage 42) on the side of the mirror carriage 48. The light-shielding film 98 moves along with the movement of the lens carriage 42 and is positioned above the shading portion 96a in a state where the shading portion 96a is tilted, thereby causing the shading correction plate 96 to malfunction (erroneously rotate). Can be prevented.

Next, the structure of the lens carriage 42 for holding the single focus lens 36 will be described with reference to FIG. As shown in FIG. 9, the lens carriage 42 has a carriage body 10 extending along a direction orthogonal to the optical axis.
The housing 102 of the bearing portion 54 is integrally formed on one side of the carriage body 100 (ie, on the side where the guide shaft 52 is provided).
The other side of the carriage main body 100 (that is, the side opposite to the side where the guide shaft 52 is provided) is in sliding contact with the upper surface of the base plate 38, and
The slide bearing plate 104 having a sliding contact surface on its lower surface that allows sliding along the optical axis direction is integrally formed.

A lens holder 106 to which the single focus lens 36 is mounted is mounted on the carriage body 100 so that the mounting position thereof can be adjusted. On the upper surface of the lens holder 106, as shown in FIG. 10, a lens fixing portion 108 to which the single focus lens 36 is fixed is provided. The lens holder 106 has a pair of positioning holes 1 that penetrate in the thickness direction while being positioned on both sides along the direction orthogonal to the optical axis of the lens fixing portion 108.
10a, 110b and these positioning holes 110a, 11
0b, mounting screws 112 for fixing the lens holder 106 to the carriage body 100.
a, 112b (shown in FIG. 2) are formed through the mounting holes 114a, 114b, respectively.

Here, these positioning holes 110a, 11
One hole 110a of Ob is formed of a long hole extending along a direction orthogonal to the optical axis. A line segment L1 connecting the centers of the two positioning holes 110a and 110b is:
It is set in advance so as to be orthogonal to the mounting axis of the single focus lens 36 in the lens fixing portion 108 (that is, the optical axis of the single focus lens 36) L2 exactly. In addition, both mounting holes 1
14a, 114b are the corresponding positioning holes 110a, 1
10b, each of which comprises an elongated hole which is adjacent to and extends along the direction orthogonal to the optical axis direction and extends along the optical axis direction.

On the other hand, as shown in FIG. 9, both mounting holes 114a and 114b are provided on the upper surface of the carriage body 100.
Are formed, and screw holes 116a and 116b into which mounting screws 112a and 112b, respectively, are screwed are formed. In addition, through holes 120a and 120b through which positioning pins 118a and 118b, which will be described later, respectively penetrate are formed on the upper surface of the carriage main body 100 so as to communicate with the positioning holes 110a and 110b, respectively. These positioning pins 118a and 118b are formed such that their respective tips are fitted in the corresponding positioning holes 110a and 110b in a tight state (that is, without rattling).

Note that these positioning pins 118a, 118
As shown in FIG. 4, b is inserted into reference holes 122a and 122b formed in advance on the base plate 38, and is set so that the respective attached states are maintained. Here, these reference holes 122a and 122b are formed so that the positioning pins 118a and 118b respectively attached thereto can pass through the corresponding through holes 120a and 120b of the lens carriage 42 in which the magnification is in the same magnification. Is set. In addition, these reference holes 122a and 122b are
A line segment L3 connecting the centers of the two is set to be exactly orthogonal to the designed optical axis.

Since the manner in which the single focus lens 36 is attached to the lens carriage 42 (that is, the adjustment structure) is set as described above, the reference hole formed on the base plate 38 during the assembly of the variable power optical apparatus 10. 1
The positioning pins 118a and 118b are attached to the reference pins 22a and 122b, respectively.
The carriage main body 100 previously slidably attached to the guide shaft 52 is moved so that 18b penetrates the corresponding through holes 120a and 120b, and then the positioning holes 110a and 110b corresponding to these positioning pins 118a and 118b. So that the lens holder 10
6 is mounted on the carriage main body 100, and the pair of mounting screws 112
The lens holder 106 can be mounted and fixed on the carriage main body 100 via a and 112b. As a result, the single focus lens 36 held by the lens holder 106 fixed and mounted on the carriage body 100 in this manner is mounted with its central axis set exactly parallel to the designed optical axis. Will be.

That is, in this embodiment, the lens holder 106 for directly holding the single focus lens 36 is placed in a state where its position is accurately defined with respect to the base plate 38 serving as a reference. The central axis of the single focus lens 36 is set to be exactly parallel to the optical axis. As a result, there is no need to accurately define the parallelism of the guide shaft 52 with respect to the optical axis and the orthogonality of the carriage main body 100 to which the lens holder 106 is attached with respect to the guide shaft 52. It will be greatly improved. In addition, in comparison with the conventional method in which the positioning of the single focus lens 36 is optically defined using a laser beam or the like, in this embodiment, the positioning can be performed mechanically. The workability of the adjustment is simplified, and an expensive measuring device is not required, and the working efficiency can be improved, so that the cost of the device can be reduced.

The pair of positioning pins 118a and 118b used for mounting the lens holder 106 are removed from the base plate 38 after the completion of the positioning operation.

The lens carriage 42 thus configured
As described above, the guide shaft 52 is provided via the bearing portion 54 integrally attached to the carriage body 100.
Are slidably guided along the optical axis direction. The bearing portion 54 includes the housing 102 integrally formed with the carriage body 100 as described above. The housing 102 has a substantially U-shaped cross section with an open lower surface. That is, the housing 102 includes a top plate portion 102a integrally extending from the carriage body 100,
Side wall portions 102b, 10 integrally and vertically falling from both edges along a direction orthogonal to the optical axis of the top plate portion 102a.
2c.

As is apparent from FIG. 2, the housing 102 has a length along the optical axis direction which is slightly longer than the length of the carriage body 100 along the optical axis direction. I have. This housing 102 is shown in FIG.
As shown in FIG. 7, upper guide portions 124a, 1 for receiving the upper half portion of the guide shaft 52 at both ends along the optical axis direction.
24b are formed, and lower guide portions 126a and 126b for receiving the lower half of the guide shaft 52 are formed directly inside both upper guide portions 124, respectively.

Here, each of the upper guide portions 124a, 124b
As shown in FIG. 12A, the bottom surface is opened, and concave portions 128 through which the guide shaft 52 is inserted are formed. Each of the recesses 128 has a rectangular lower portion 12 with a bottom half opened and a lower half of the guide shaft 52 inserted therethrough.
8a is connected to the upper side of the lower portion 128a, the upper half of the guide shaft 52 is inserted therethrough, and a right isosceles triangle having an open lower surface (communicating with the rectangular upper surface of the lower portion 128a) as an oblique side. And an upper portion 128b. On the other hand, each lower guide part 126a, 12
As shown in FIG. 12B, through holes 130 through which the guide shafts 52 are inserted are formed in 6b. Each through hole 1
30 is connected to a rectangular upper portion 130a into which the upper half of the guide shaft 52 is inserted, and is connected to the lower side of the upper portion 130a. The lower half of the guide shaft 52 is inserted and opened (the upper portion). And a lower portion 130b presenting a right-angled isosceles triangle having the upper surface as the hypotenuse.

As a result, as shown in FIG. 12C, the upper guide portions 124a,
In the state where the lower guide portions 4b and the adjacent lower guide portions 126b and 126b are combined, square openings 132 through which the guide shaft 52 is inserted along the optical axis direction are provided. The square shape of the opening 132 is
Each side will be configured to be inclined at 45 degrees to the horizontal or vertical axis.

Here, in this embodiment, as described above, the length of the bearing portion 54 along the optical axis direction of the housing 102 is set relatively short. In this embodiment, even if the guide length is relatively short along the optical axis, the lens carriage 42 to which it is attached is guided to move along the optical axis without fail. The upper guide portions 124a and 124b are
A single torsion coil spring 134 is provided so as to elastically contact the outer periphery of the coil 2. The torsion coil spring 134 is disposed substantially at the center of the housing 102 along the optical axis direction.

As described above, the upper guide portions 126a and 126b are elastically brought into contact with the guide shaft 52 by utilizing the elastic force of the torsion coil spring 134. In detail, the outer peripheral surface of the guide shaft 52 is Each upper guide section 12
4a, upper portion 128 of recess 128 formed in 124b
b comes into contact with the mutually orthogonal slopes. In this way, the guide shaft 52 elastically contacts the upper guide portions 126a and 126b at two points, and as a result, the two-dimensional position of the lens carriage 42 in a plane perpendicular to the optical axis is determined. It can be specified uniquely.

In this embodiment, as shown in FIG. 13, the torsion coil spring 134 is wound only three times, and has a coil portion 134a loosely fitted on the outer periphery of the guide shaft 52, and a coil portion 134a. And end portions 134b and 134c extending linearly from the end. Here, as shown in FIG. 13, these ends 134b and 134c are set so as to extend so as to form a relatively small acute angle when no external force acts on them.

On the other hand, openings are formed in both side walls 102b and 102c of the housing 102 so that both ends 134b and 134c of the torsion coil spring 134 are inserted at a position substantially at the center along the optical axis direction of the housing 102. 136a and 136b are formed respectively. The openings 136a and 136b are provided at both ends 134b and 134c of the torsion coil spring 134 in the natural posture shown in FIG.
Are elastically deformed so as to widen the angle between them, as shown in FIG. 14, and the corresponding openings 136a, 136
b. Thus, both ends 134b, 136
By inserting the corresponding openings 136a and 136b into the openings c and c, the ends 134b and 136c exert an elastic biasing force in a direction of approaching (closing) each other.
As a result, the housing 102 is urged so as to be pressed relatively downward with respect to the guide shaft 52 inserted through the coil portion 134a of the torsion coil spring 134.

In other words, by using (attaching) the torsion coil spring 134 in this manner, each upper guide portion 126 to the guide shaft 52 as described above is attached.
The lower surfaces of the a and 126b orthogonal to each other are elastically contacted at two points, so that the two-dimensional position in the plane orthogonal to the optical axis is uniquely defined. That is, as described above, in this embodiment, even when the length of the bearing portion 54 with respect to the guide shaft 52 along the optical axis direction is set short, the use of the torsion coil spring 134 As a result, a state of being reliably guided along the optical axis is achieved.

Here, such a torsion coil spring 1
In a state in which the bearing portion 54 is elastically supported by the guide portion 52 with respect to the guide shaft 52, as shown in FIG. 14, the guide shaft 52 inserted into the coil portion 134 a of the torsion coil spring 134 has a coil portion 134 a Will come into contact with the lower part of the inner peripheral surface. That is, the contact state between the guide shaft 52 and the coil portion 134a is ideally a point contact. As a result, with the movement of the lens carriage 42 along the optical axis direction, the guide shaft 52 and the coil portion 13 of the torsion coil spring 134 are moved.
4a slides with each other, but the frictional resistance at that time is suppressed as much as possible, especially when the moving speed of the lens carriage 42 is low, it becomes substantially negligible. .

Next, the above-mentioned movable reflection mirrors 44, 46
The structure of the mirror carriage 48 for holding the mirror is shown in FIG.
19 will be described with reference to FIG.

As shown in FIG. 15, the mirror carriage 48 has a carriage main body 138 extending along a direction orthogonal to the optical axis, similarly to the lens carriage 42.
On one side of the carriage main body 138 (that is, on the side where the guide shaft 52 is disposed), the housing 140 of the bearing portion 56 described above is integrally formed. Further, the other side of the carriage main body 138 (that is, the guide shaft 5)
2), the base plate 3
A slide bearing plate 142 (shown in FIG. 2) having a sliding contact surface on its lower surface that allows the mirror carriage 48 to slide along the optical axis direction is integrally attached to the upper surface of the slide carriage 8.

An opening 144 is formed in the carriage body 138 to allow the image light reflected by the movable reflection mirror 44 above the base plate 38 to pass toward the movable reflection mirror 46 below the base plate 38. I have. One mirror support plate 146 for supporting one side of the pair of upper and lower movable reflection mirrors 44 and 46 is attached to one side edge of the opening 144 in an upright and fixed state. On the other side edge of the opening 144, another mirror support plate 148 for supporting the other side portions of the pair of upper and lower movable reflection mirrors 44 and 46 respectively adjusts the mounting position along the optical axis direction. Mounted in an upright position.

More specifically, as shown in FIG. 16, one mirror support plate 146 is formed with support openings 150 and 152 through which one sides of the movable reflection mirrors 44 and 46 are inserted, respectively. On the side corresponding to the surfaces (reflection surfaces) of the movable reflection mirrors 44 and 46 on the peripheral edges of these support openings 150 and 152, a support for supporting the reflection surfaces of the corresponding movable reflection mirrors 44 and 46 at two points at both ends. Projections 150a, 150b; 1
52a and 152b are formed to protrude. Peripheral portions opposed to the peripheral portions on which the support protrusions 150a, 150b; 152a, 152b are formed, and the movable reflecting mirrors 44, 46.
Between the support projections 150a and 150b;
In a state corresponding to 2a and 152b, respectively, the elastically deformable pressing holding piece 154 is pushed in. The movable reflection mirrors 44 and 46 are supported by the support protrusions 150a and 150b;
The mirror support plate 146 of the mirror carriage 48 holds one side of the movable reflection mirrors 44 and 46 by pressing and biasing the mirror reflectors a and 152b.

On the other hand, as shown in FIG. 17, the other mirror support plate 148 has support openings 156 and 158 through which the other side portions of the movable reflection mirrors 44 and 46 are inserted. On the side corresponding to the surfaces (reflection surfaces) of the movable reflection mirrors 44 and 46 on the peripheral edges of these support openings 156 and 158, a support for supporting the reflection surfaces of the corresponding movable reflection mirrors 44 and 46 at one central point. The protrusions 156a and 158a are formed to protrude. The peripheral edge opposite to the peripheral edge on which the support protrusions 156a and 158a are formed and the movable reflection mirror 44,
The pressing holding piece 160 which can be elastically deformed is in a state corresponding to the supporting protrusions 156a and 158a, respectively, between the pressing holding piece 160 and the rear surface of the holding projection 160.
Is breached. The movable reflection mirrors 44, 46 are pressed against the support protrusions 156a, 158a by the elastic restoring force due to the elastic deformation of the press holding pieces 160, so that the other mirror support plate 148 of the mirror carriage 48 is pressed.
It holds the other side of the movable reflecting mirrors 44, 46.

In this way, each movable reflection mirror 44, 4
6 are support projections 150a, 150b;
At two points by 52a and 152b, it is supported at one point by the support protrusions 156a and 158a on the other side, so that it is stably held as a so-called three-point support.

Here, as described above, the other mirror support plate 148 is attached to the carriage main body 138 so that its position can be adjusted along the optical axis direction. Specifically, the carriage body 138 is provided at the other side edge of the opening 144.
The attachment piece 162 bent so as to stand up from is provided integrally. On the other hand, the other mirror support plate 148
Slits 164 and 166 extend along the optical axis of the carriage body 138 so that both peripheral edges along the optical axis of the opening 144 are fitted substantially at the center in the height direction. It is formed in a state. The distance D1 between the slits 164 and 166 along the optical axis direction is:
The opening 144 is set to be slightly shorter than the formed length D2 along the optical axis direction. In this way, the other mirror mounting plate 148 is movable along the optical axis direction by the difference (D2-D1) of this distance, and the carriage main body 13 is moved.
8 will be attached.

On the other hand, the other mirror support plate 148 has a screw hole 168 for attachment. The mounting piece 162 has a mounting screw 172 (shown in FIG. 2).
Is formed through which a mounting hole 170 is inserted. The mounting hole 170 is formed by an elongated hole extending along the optical axis direction. As a result, the other mirror support plate is mounted via the mounting screw 172 in a state where the longitudinal axes of the pair of upper and lower movable reflection mirrors 44 and 46 are accurately positioned so as to be orthogonal to the optical axis by the positioning operation described later. 1
By fixing the 46 to the mounting piece 162, a fixing operation for positioning the movable reflecting mirrors 44 and 46 is achieved.

Next, a description will be given of a positioning structure for positioning the movable reflecting mirrors 44 and 46 so that their longitudinal axes are orthogonal to the optical axis.

First, as shown in FIG. 16, one mirror support plate 146 is
4 and 46 are inserted into the support openings 150 and 152, respectively, and the inserted state is elastically held by the pressing support pieces 154, so that the mounting surface of the one support opening 150 to the carriage body 138 is provided. Is 45 degrees along the clockwise direction in the drawing, and the inclination angle from the mounting surface of the other support opening 152 to the carriage main body 138 is
It is set so that it can be attached in a precisely controlled state so as to be within a predetermined accuracy of 45 degrees along the counterclockwise direction in the figure. Further, the right edge 1 of the one mirror support plate 146 in the drawing from a predetermined reference position of the lower movable reflection mirror 46 is shown.
The distance along the optical axis direction up to 46a is set so as to be formed in a state that is accurately managed so as to be within a predetermined accuracy.

As shown in FIG. 17, the other mirror support plate 148 supports the other side of the pair of upper and lower movable reflection mirrors 44 and 46 in the same manner as the one mirror support plate 146. 156 and 158, and the inserted state is elastically held by the pressing support piece 160, so that the carriage main body 13 of the other support opening 156 is inserted.
The angle of inclination of the carriage main body 1 of the other support opening 158 is 45 degrees along the clockwise direction in FIG.
The angle of inclination from the mounting surface to the surface 38 is set to 45 degrees along the counterclockwise direction in the figure, so that the mounting can be performed in a precisely controlled state so as to be within a predetermined accuracy. In addition, the distance along the optical axis direction from the predetermined reference position of the lower movable reflection mirror 46 to the right edge 148a of the other mirror support plate 148 in the drawing is accurately controlled so as to be within a predetermined accuracy. It is set to be formed in a state.

On the other hand, the right side edges 146a and 148a of the two mirror support plates 146 and 148 are respectively connected to the right side of the opening 40 formed in the base plate 38 so that the mirror carriage 48 is entirely inserted. It is set so that it can contact the edge. Here, the right edge 146a, 1 of the opening 40 in the drawing of each of the two mirror support plates 146, 148 is shown.
As shown in FIG. 4, the portions 40a and 40b with which the respective 48a contact each other are accurately controlled so as to be in a predetermined accuracy so as to be aligned with each other along a direction orthogonal to the optical axis. It is set to be formed by. The abutted portions (that is, the positioning portions) 40a and 40b are formed at positions outside the range of movement of the mirror carriage 48 during the zooming operation.

Since the manner in which the movable reflecting mirrors 44 and 46 are attached to the mirror carriage 48 (that is, the adjustment structure) is set as described above, both mirrors are attached to the mirror carriage 48 during the assembling work of the variable magnification optical apparatus 10. With the pair of upper and lower movable reflecting mirrors 44 and 46 mounted via the support plates 146 and 148, the mounting screw 172 described above is loosened, and the mirror carriage 48 is moved fully to the right in the drawing. The other mirror support plate 14
8 is movable along the optical axis direction with respect to the mirror carriage 138. Therefore, as shown in FIG.
a and 148a simultaneously abut the positioning portions 40a and 40b formed so as to be perpendicular to the optical axis. As a result, both mirror support plates 146, 14
The pair of upper and lower movable reflection mirrors 44 and 46 attached to and supported by 8 are in a state where their extension axes are exactly perpendicular to the optical axis. Then, by tightening the mounting screw 172, the mirror carriage 48 to which the pair of upper and lower movable mirror carriages 44 and 46 is attached is assembled in a state where the orthogonal state is fixed.

That is, in this embodiment, both mirror support plates 146 and 148 for directly holding the pair of upper and lower movable reflection mirrors 44 and 46 are connected to the base plate 3 serving as a reference.
In a state where the position of the movable reflecting mirror 8 is accurately defined, specifically, the extension axes of the two movable reflecting mirrors 44 and 46 are set to be exactly perpendicular to the optical axis. As a result,
As in the case of the lens carriage 42 described above, it is necessary to accurately define the parallelism with respect to the optical axis of the guide shaft 52 and the orthogonality of the carriage main body 138 to which the mirror support plates 146, 148 are attached with respect to the guide shaft 52. As a result, the assemblability of the variable power optical device 10 is greatly improved. Also, in comparison with the conventional method in which the positioning of the two movable reflection mirrors 44 and 46 is optically defined by using a laser beam or the like, in this embodiment, mechanically, that is, abutment on a reference surface is performed. Simplifies the work of this positioning operation, and eliminates the need for expensive measuring devices.
Work efficiency can be improved, and the cost of the apparatus can be reduced.

Next, the mirror connecting plate 94 constituting the second driving force transmitting mechanism 64 for transmitting the rotational driving force of the driving motor 60 to the mirror carriage 48 as a linear driving force is transmitted to the mirror carriage 48. The mounting mode will be described.

First, as shown in FIG. 15, the housing 140 of the bearing portion 56 integrally connected to one side of the carriage main body 138 of the mirror carriage 48 described above has the right side of the mirror connecting plate 94 in FIG. A pair of mounting holes 174a and 174b to which the ends are mounted are formed. Each of the mounting holes 174a and 174b is formed of a long hole extending along a direction orthogonal to the optical axis direction. On the other hand, at the right end in the figure of the mirror connecting plate 94, screw holes for screwing mounting screws 176a and 176b (shown in FIG. 2), which are respectively inserted into the corresponding mounting holes 174a and 174b, are not shown, but are formed. Have been.

In this manner, a pair of mounting screws 176a and 176 are provided in a state where the right end in the figure of the mirror connecting plate 94 is superimposed on the lower surface of the housing 140 of the bearing portion 56.
6b is screwed into the corresponding screw hole with the corresponding mounting holes 174a and 174b inserted therethrough, whereby the mirror connecting plate 94 is mounted on the housing 140 of the bearing portion 56.
In other words, in other words, the mirror carriage 48 is integrally joined. On the other hand, by loosening these mounting screws, the mirror connecting plate 94 becomes movable in the direction orthogonal to the optical axis.

As described above, the manner in which the mirror connecting plate 94 is mounted on the mirror carriage 48 is configured, and as described below, errors in the focal length of the single focus lens 36 and errors in the production of mechanical parts will be described. Even if an error or the like occurs, the optical characteristics can be made to exactly match the design characteristics with a simple adjustment operation.

That is, as described above, the single focus lens 36 is mounted on the lens carriage 42 and its central axis is adjusted so as to be exactly parallel to the optical axis. 46 to the left and right mirror support plates 146, 1
The mirror connecting plate 94 is mounted on the mirror carriage 48 via the mirror 48 and adjusted so that its longitudinal axis is perpendicular to the optical axis. Then, the mounting screws 176a and 176b are loosened, and the mirror connecting plate 94 is moved in the horizontal plane. To allow movement along a direction orthogonal to the optical axis.

In this state, by manually moving and driving the mirror connecting plate 94 by, for example, an operator, the sliding pin 92 fitted and fixed to the front end (left end in the drawing) of the mirror connecting plate 94 is removed. Long arm 8 of lever 84
The position of insertion into the long hole 90 formed at the tip of 4b is changed.

More specifically, when the mirror connecting plate 94 is to be moved in a direction perpendicular to the optical axis, as shown in FIG. Since it extends along the direction orthogonal to the optical axis, even if the mirror connecting plate 94 moves along the direction orthogonal to the optical axis, the position of the mirror carriage 48 to which the mirror connecting plate 94 is connected in the optical axis direction is It will not change. On the other hand, as shown in FIG. 7B, when the magnification changes to the enlargement side, the elongated hole 90 is inclined with respect to the direction orthogonal to the optical axis, and the elongated hole 90 is formed. The position of the lever 84 is fixed because the cam follower 86 attached to the lever 84 is fitted in the cam groove 82 of the cam plate 80. The mirror connecting plate 94 is forced to move obliquely. As a result, the mirror carriage 48 to which the mirror connecting plate 94 is connected is moved along the optical axis direction. In this way, with the change of the fitting position, the separation distance between the lens carriage 42 and the mirror carriage 48 is minutely changed, and the apparent lever ratio is changed. Also, as shown in FIG. 7C, when the magnification changes to the reduction side, the apparent lever ratio is changed in the same manner as when the magnification changes to the enlargement side as described above. In this manner, in this embodiment, by moving the mirror connecting plate 94 along the optical axis direction, the optical positional relationship at the time of equal magnification and enlargement or at the time of equal magnification and reduction is changed. As a result, the above-mentioned optical characteristics are adjusted so as to exactly match the designed optical characteristics.

Next, the structure of a bearing 56 for slidably supporting the mirror carriage 48 along the optical axis via the guide shaft 52 will be described with reference to FIG.

As described above with reference to FIG. 15, the bearing portion 56 is provided for the carriage main body 13 of the mirror carriage 48.
8 has a housing 140 formed integrally therewith. As is apparent from FIG. 15, the housing 140 is set so that its length along the optical axis direction is slightly shorter than the length along the axial direction of the carriage body 138 to which it is joined. As shown in FIG. 19, upper guide portions 178 for receiving the upper half of the guide shaft 52 are provided at both ends of the housing 140 along the optical axis direction.
a and 178b are attached in a state of being integrally lowered. Each of the upper guide portions 178a and 178b has
A bottom surface is opened, and a concave portion 180 into which the guide shaft 52 is inserted is formed. The lower half of the guide shaft 52 is inserted into each of the recesses 180, and the lower half 180 a having an open bottom is connected to the lower half 180 a, and the upper half of the guide shaft 52 is inserted into the recess 180. And an upper portion 180b which is a right-angled isosceles triangle having an open lower surface (communicating with the rectangular upper surface of the lower portion 180a) as an oblique side.

Here, in this embodiment, as described above, the length of the bearing 140 along the optical axis direction of the housing 140 is set relatively short. In this embodiment, even if the guide length is relatively short along the optical axis direction, the mirror carriage 48 to which the mirror carriage is attached is guided to surely move along the optical axis direction. One coil spring 182 for urging the housing 140 of the bearing portion 56 obliquely downward and rightward in FIG. 3 in a vertical plane passing through the center of the housing 140 is provided. That is, the coil spring 182 is
2 is exerted simultaneously along the optical axis with a component force biasing rightward in FIG. 2 and a component force biasing downward.

The upper end of the coil spring 182 is engaged with the housing 140 via a pair of engaging grooves 184a, 184b formed on the upper surface of the carriage body 138 as shown in FIG. It is locked by a locking piece 186 integrally attached to the lower surface of the base plate 38. The engagement position of the coil spring 182 is set so as to extend in a vertical plane passing through the optical axis.

The upper guide portions 178a, 178a, 17b are provided by utilizing the urging force acting below the coil spring 182.
8b and the guide shaft 52 resiliently contact with each other. In detail, the outer peripheral surface of the guide shaft 52 is formed on a slope orthogonal to the upper portion 180b of the concave portion 180 formed in each of the upper guide portions 178a and 178b. Each comes into elastic contact. In this manner, the guide shaft 52 elastically abuts the guide portions 178 at two points, and as a result, the two-dimensional position of the mirror carriage 48 in a plane orthogonal to the optical axis is uniquely defined. You can do it.

As described above, in this embodiment, the length of the bearing 54 of the lens carriage 42 along the optical axis and the length of the bearing 56 of the mirror carriage 48 along the optical axis are both shortened. It can be set. For this reason, even if the lens carriage 42 and the mirror carriage 48 are respectively driven to move in the optical axis direction in accordance with the scaling operation of the scaling control mechanism 58, they do not interfere with each other. Guide shaft 52
Are commonly used, and a configuration in which each is slidably guided along the optical axis direction is achieved.

As described above, according to this embodiment, the guide shaft for guiding the lens carriage 42 slidably along the optical axis direction and the mirror carriage 48 slidably along the optical axis direction. By setting the length along the optical axis direction of each of the bearings 54 and 56 to be short with the guide shaft for guiding the guide shaft, the guide shaft 52 can be shared by one guide shaft 52. By reducing the score, a reduction in cost can be achieved.

On the other hand, the mirror carriage 48 is always moved to the lens carriage 42 by the urging force of the coil spring 182 toward the right side in the drawing along the optical axis direction.
Will be urged to move away from.
As a result, the sliding pin 92 fitted and fixed to the distal end of the mirror connecting plate 94 integrally connected to the mirror carriage 48 becomes a long hole 90 formed in the distal end of the longer arm portion 84b of the lever 84. Inside, the urging force is constantly directed rightward in the figure, and the state of elastically contacting the edge on the mirror carriage 48 side is maintained.

As a result, in this embodiment, the clearance existing in the engaging portion of the components constituting each drive system,
For example, the clearance between the sliding pin 92 and the sliding pin 92 generated when the sliding pin 92 is fitted into the elongated hole 90 is absorbed.
The variable power operation is smoothly performed without play.

The present invention is not limited to the configuration of the embodiment described above, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

For example, in the above-described embodiment, the torsion coil spring 134 used for the bearing 54 that guides the lens carriage 42 slidably with respect to the guide shaft 52 has a three-turn coil portion 134a. As described above, the present invention is not limited to such a configuration, and may be, for example, one turn or any number of turns.

In the above-described embodiment, the bearing 54 described above is provided with the lower guides 126a and 126b together with the upper guides 124a and 124b. Without being limited, for example, a configuration in which the lower guide portion is omitted, in other words,
Similar to the configuration of the bearing portion 56 that guides the mirror carriage 48 slidably with respect to the guide shaft 52, the mirror carriage 48 may be configured to include only the upper guide portion with which the upper half portion of the guide shaft 52 contacts. is there.

[0090]

As described in detail above, according to the first aspect of the present invention, the variable power optical apparatus according to the present invention moves the image forming lens and the mirror along the optical axis direction, thereby obtaining the original image. In a variable power optical device that forms an image in a state where
A bearing part slidably guided in a state of being elastically contacted with a guide shaft extending along the optical axis direction through a torsion coil spring is integrated with a carriage supporting the imaging lens or the mirror. It is characteristically attached.

Further, the variable power optical device according to the present invention includes:
According to the second aspect, the single focus lens and the mirror interposed between the single focus lens and the image forming surface are moved along the optical axis direction to move from the document surface to the single focus lens. In a variable power optical device that changes the ratio of the image to the original image by appropriately changing the distance from the single focus lens to the image forming surface, a guide shaft extending along the optical axis direction; A carriage for holding the single focus lens or mirror, and bearing means for slidably guiding the carriage while riding on the guide shaft;
And a pressing means for pressing the bearing means against the guide shaft.

Further, the variable power optical device according to the present invention includes:
According to the fifth aspect, the single focus lens and the mirror interposed between the single focus lens and the image forming surface are moved along the optical axis direction to move from the document surface to the single focus lens. In a variable power optical apparatus in which the ratio of image formation to a document image is variable by appropriately changing the distance from the single focus lens to the image plane, one guide extending along the optical axis direction is used. A shaft, a lens carriage for holding the single focus lens, first bearing means for slidably guiding the lens carriage to the guide shaft, a mirror carriage for holding the mirror, and a guide for the mirror carriage. Second bearing means for slidably guiding the shaft.

Therefore, according to the present invention, a variable power optical device capable of achieving cost reduction can be provided.

Further, according to the present invention, a variable power optical device capable of reducing the size of the entire device is provided.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a schematic configuration of an electrophotographic apparatus to which an embodiment of a variable power optical device according to the present invention is applied.

FIG. 2 is a plan view showing a configuration of an embodiment of a variable power optical device according to the present invention.

FIG. 3 is a front sectional view showing a configuration of a variable power optical device shown in FIG. 2;

FIG. 4 is a plan view showing a planar shape of a base plate constituting the variable power optical apparatus.

FIG. 5 is a perspective view showing an integrally formed state of a gear ring, a driving pulley, and a cam plate which constitute the variable power optical apparatus.

FIG. 6 is a diagram showing the relationship between the magnification and the amount of movement between the single focus lens and the mirror carriage.

FIG. 7A is a plan view showing a swing relationship between a cam groove shape and a lever in a state where a magnification ratio is the same magnification.

FIG. 7B is a plan view showing the swing relationship between the cam groove shape and the lever in a state where the magnification is on the enlarged side.

FIG. 7C is a plan view showing the swing relationship between the cam groove shape and the lever in a state where the magnification is on the reduction side.

FIG. 8 is a perspective view showing a configuration of a shading correction plate.

FIG. 9 is a plan view showing a configuration of a carriage main body of the lens carriage.

FIG. 10 is a plan view showing a configuration of a lens holder.

FIG. 11 is a front sectional view showing a configuration of a housing of a lens carriage bearing.

FIG. 12A is a view showing the state of formation of the upper guide section,
FIG. 3 is a side sectional view showing a state cut along the line AA in FIG.

FIG. 12B is a view showing a state in which a lower guide portion is formed.
FIG. 3 is a side sectional view showing a state of being cut along the line BB in FIG.

FIG. 12C is a side view showing a state where the guide shaft is inserted into the lens carriage bearing.

FIG. 13 is a front view showing the torsion coil spring in its natural state.

FIG. 14 is a side view showing a state in which the torsion coil spring is mounted on a lens carriage bearing.

FIG. 15 is a plan view showing a configuration of a carriage main body of the mirror carriage.

FIG. 16 is a front view showing the configuration of one mirror support plate fixed to the mirror carriage.

FIG. 17 is a front view showing the configuration of the other mirror support plate fixed to the mirror carriage.

FIG. 18 is a side view showing a configuration of a bearing unit for a mirror carriage.

FIG. 19 is a cross-sectional view showing a configuration of a bearing for supporting a mirror carriage slidably along a direction of an optical axis via a guide shaft.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Variable-magnification optical apparatus 12 Electronic copying apparatus 14 Housing 16 Platen glass 18 Electronic copying mechanism 20 Photosensitive drum 22 Scanning optical system 24 Lamp 26 First reflection mirror 28 Second reflection mirror 30 Third reflection mirror 32 Full-speed unit 34 Half speed unit 36 Single focus lens 38 Base plate 40 Opening 40a; 40b Contacted part (that is, positioning part) 42 Lens carriage 44; 46 Movable reflection mirror 48 Mirror carriage 50 Fixed reflection mirror 52 Guide shaft 54 Lens carriage bearing 56 Mirror carriage bearing portion 58 Zoom control mechanism 60 Drive motor 62 First drive force transmission mechanism 64 Second drive force transmission mechanism 66 Drive gear 68 Gear ring 70 Support shaft 72 Drive pulley 74; 76 Follower pulley 78 Transmission wire 80 Cam pre G 82 Cam groove 84 Lever 84a; 84b Arm unit 86 Cam follower 88 Support shaft 90 Elongated hole 92 Sliding pin 94 Mirror connecting plate 96 Shading correction plate 96a Shading unit 96b Operating unit 96c Shaft unit 98 Light shielding film 100 Carriage body 102 Housing 102a Top Plate portion 102b; 102c Side wall portion 104 Slide bearing plate 106 Lens holder 108 Lens fixing portion 110a; 110b Positioning hole 112a; 112b Mounting screw 114a; 114b Mounting hole 116a; 116b Screw hole 118a; 118b Positioning pin 120a; 120b Through hole 122a; 122b Reference hole 124a; 124b Upper guide part 126a; 126b Lower guide part 128 Recess 130 Through hole 132 Opening 134 Torsion coil 134a Coil portion 134b; 134c End 136a; 136b Opening 138 Carriage body 140 Housing 142 Slide bearing plate 144 Opening 146 One mirror support plate 146a Right side edge 148 The other mirror support plate 148a Right side edge 150; 152 One side support Opening 150a, 150b; 152a, 152b One supporting projection 154 One pressing supporting piece 156; 158 The other supporting opening 156a; 158a The other supporting projection 160 The other pressing supporting piece 162 Mounting piece 164; 166 Slit 168 Screw hole 170 Mounting Hole 172 Mounting screw 174a; 174b Mounting hole 176a; 176b Mounting screw 178 Guide part 180 Depression 182 Coil spring 184a; 184b Lock groove 186 Lock piece.

Claims (5)

(57) [Scope of request for utility model registration] 1. A variable power optical device for forming an original image in a zoomed state by moving an imaging lens and a mirror along an optical axis direction, wherein a guide shaft extending along the optical axis direction is provided. Wherein a bearing portion slidably guided in a state of being elastically contacted via a torsion coil spring is integrally attached to a carriage supporting the imaging lens or the mirror. Optical device. 2. A single focus lens and a mirror interposed between the single focus lens and an image forming surface are moved along the optical axis direction to determine the distance from the document surface to the single focus lens and the single focus lens. A variable-magnification optical device that varies a ratio of an image to a document image by appropriately changing a distance from a focal lens to an image forming surface; a guide shaft extending along an optical axis direction; Or a carriage for holding a mirror, bearing means for slidably guiding the carriage while riding on the guide shaft, and pressing means for pressing the bearing means against the guide shaft. A variable power optical device. 3. The bearing means includes a housing integrally attached to the carriage, and guide portions slidingly contacting an upper portion of the guide shaft are formed at both ends of the housing along the optical axis direction, respectively. The variable-magnification optical device according to claim 2, wherein the press-contact means includes a torsion coil spring having both ends locked to the housing and a coil portion through which the guide shaft is inserted. 4. The variable power optical device according to claim 3, wherein one of the torsion coil springs is attached to a substantially central portion along the optical axis direction of the housing. 5. A single focus lens and a mirror interposed between the single focus lens and the image forming surface are moved along the optical axis direction to determine the distance from the document surface to the single focus lens and the single focus lens. A variable-magnification optical device that changes the ratio of the image to the original image by appropriately changing the distance from the focus lens to the image forming surface, wherein one guide shaft extending along the optical axis direction; A lens carriage for holding a single focus lens; first bearing means for slidably guiding the lens carriage to the guide shaft; a mirror carriage for holding the mirror; and sliding the mirror carriage to the guide shaft. And a second bearing means for guiding freely.