JPH052142U - Image reading optical system zooming device - Google Patents

Abstract

(57) [Summary] [Object] To provide a correction mechanism capable of reliably performing position correction at the time of zooming of a zooming mirror in a zooming device of an image reading optical system such as a copying machine with a simple structure. An optical system including a document exposure light source, a zooming mirror that is arranged orthogonally and converts an optical path, and a main lens, and a drive system that moves the main lens and the zooming mirror at a predetermined ratio. In the variable magnification device of the image reading optical system for varying the magnification by moving the lens and the variable magnification mirror along the optical axis of the optical system, the variation of the mount for holding the variable magnification mirror. A variable-magnification device for an image reading optical system, characterized in that a displacement amount correction mechanism for correcting the position at the time of magnification is provided, and the correction mechanism is constituted by a disk cam and a fixed pin.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

  The present invention relates to a scaling device for an image reading optical system in a copying machine or an image reading device, Especially, it relates to the improvement of the drive amount correction mechanism of the optical path conversion mirror in the variable power optical system. is there.

[0002]

[Prior art]

  FIG. 1 is a block diagram showing an example of an optical system 10 of an electrophotographic copying machine. Place on platen 11 The document D thus formed is illuminated by the exposure lamp 12 and the lamp house 13 and its reflected light is reflected. The first mirror 14 bends the optical path at a right angle to form a V-shaped mirror unit. -15A, incident on the third mirror 15B. The optical path is bent 180 ° with the second and third mirrors 15A and 15B. The formed beam passes through the main lens 16 of the image forming system and again forms the V-shaped mirror unit. It is incident on the 4th mirror 17A and the 5th mirror 17B, and the direction is changed by 180 °. Then, the image of the original is formed on the photosensitive drum 21 of the image forming unit 20.

[0003]   The method of changing the magnification in the image reading optical system of a copying machine or image reading device is as follows.   Insert an auxiliary lens in front of and behind the main lens to change the focal length of the main lens. To move the position of the pixel relatively to form a scaled image,   Change the total optical path length from the document surface to the photoconductor surface and move the position of the main lens. To form a scaled image,   There is. In general, there are many copying machines adopting the method of.

[0004]   Now, the focal length of the main lens is constant, and the optical path length and the position of the main lens are moved. System, the focal length of the main lens is f, the distance from the document surface to the main lens Is a, the distance from the main lens to the photosensitive surface is b, and the magnification is m, the following general formula Is established.

[0005]   (1 / a) + (1 / b) = (1 / f)   In this general formula, in the case of unity magnification, m = a / b = 1 and a = b = 2f. Therefore, the total optical path length is L = a + b = 4f.

[0006]   Next, in the case of zooming, m1 = a1 / b1 and the further the m1 is from 1, the more total light The road length extends to L1 = a1 + b1> 4f. That is, the total optical path length L1 is equal to The time is the shortest distance, and the total optical path length L1 becomes longer for both expansion and contraction.

[0007]   In order to satisfy this condition, generally the main lens (lens slide unit) And the V-shaped mirror unit (mirror slide unit) are moved. .

[0008]   However, in reality, in each zoom state, the aberration of the main lens and the focus The optimal image may be formed at a position different from the theoretical value due to variations in point distance. is there. Also, because this aberration increases in proportion to the magnification change, we considered the required performance. Above, for example, correct the position of the mirror slide unit at a certain magnification. It is common to do.

[0009]   As an example of a conventional correction method, a mirror plate using a cam plate provided with a cam groove is used. The ride unit is moved to adjust the displacement by a predetermined amount.

[0010]   As other correction means, Japanese Patent Laid-Open Nos. 59-128504 and 55-173949 can be used. It is disclosed.

[0011]

[Problems to be solved by the device]

  The cam groove of the cam plate is about the same as the moving amount of the V mirror slide unit. The length of the slide unit is required and it must be installed parallel to the moving direction of the slide unit. There was a point. Overlap and adjust after assembly with the holes for adjusting the eccentricity of the cam plates. Therefore, it is necessary to expose the cam plate to the outer peripheral surface. Like this The size of the mount is large and the mounting position is almost limited due to its functional limitation. This was one of the factors that greatly hindered the downsizing of the copier variable magnification operation device.

[0012]   The present invention reliably and accurately holds the movement of the V mirror unit and the change of the optical path length. Compact, low-priced copy machine zoom without compromising the function of the copy machine zoom optical system It is intended to provide a moving device.

[0013]

[Means for Solving the Problems]

  A zooming device for an image reading device according to the present invention that achieves the above-mentioned object includes a light source for exposing an original, An optical system including a variable power mirror arranged orthogonally and converting an optical path, and a main lens; A drive system for moving the main lens and the variable-magnification mirror at a predetermined ratio, Zooming is performed by moving the lens and the zooming mirror along the optical axis of the optical system. When changing the magnification of the frame that holds the magnification changing mirror in the magnification changing device of the image reading optical system It is characterized in that a displacement amount correcting mechanism for correcting the position of is provided.

[0014]   Further, the scaling device of the image reading device of the present invention is a mount for holding the scaling mirror. The displacement amount correction cam that corrects the position during zooming and the mirror holding stand responds to the zooming value. And a fixed base that abuts against the correction cam. And a fixed base provided with a restriction pin for restricting the moving direction of the movable base, and the fixed base. Consists of a fixed stand and a base for fixing and supporting the stand for holding the mirror It is characterized by.

[0015]   Further, the zooming device of the image reading device of the present invention is a mount for holding the zooming mirror. And a movable mount equipped with a displacement amount correction cam for correcting the position during zooming, And a drive source that moves the mirror holding frame according to the zoom value. And a fixed base provided with a restriction pin for restricting the movable direction of the movable base, and the fixed base It consists of a pedestal and a base that supports the mirror holding gantry by positioning and fixing it. It is a feature.

[0016]

【Example】   An embodiment of the magnification varying device of the image reading device of the present invention is shown in FIGS.

[0017]   FIG. 2 is a perspective view of the magnification changing device, and FIG. 3 is a front sectional view of the V mirror unit mount moving device. 4 is a plan view of the moving device.

[0018]   The drive motor (stepping motor) M1 is mounted on the motor mount 2. Further, it is fixedly mounted on the movable mount (V mirror correction base) 3. The movable base 3 Includes a timing pulley TP2 and a drum pulley 4 which are integrally formed on the shaft. It is supported. Timing pulley TP fixed to the drive shaft of the drive motor M1 A timing belt TB1 is wound between the timing belt TB1 and the timing pulley TP2, It is tense by the sheen pulley 6.

[0019]   A disc cam 5 is locked on the upper surface of the drum pulley 4 so that the rotation direction can be adjusted. There is. That is, the circular disc cam 5 has two arc-shaped lengths formed in the circumferential direction. Grooves 5a, 5b are provided and fixed on the drum pulley 4 by screws. . A cam curved surface 5c having a gradually increasing radius is formed on the circumference of the disc cam 5. . As the shape of the disc cam 5, a cam curved surface whose radius gradually decreases is used. There are also cases.

[0020]   The movable pedestal 3 is provided with three long groove portions 3a, 3b, 3c, and the fixed pedestal (V Step surface of the three regulating pins 8a, 8b, 8c protruding to the upper surface side of the mirror correction table 7 Placed on top. A small diameter pin portion is formed at each central tip of the regulating pins 8a, 8b, 8c. The long groove portions 3a, 3b, 3c are fitted into the respective pin portions, The movable pedestal 3 is movable only in the longitudinal direction.

[0021]   A fixing pin (cam abutment shaft) 9 is vertically planted on a part of the fixed base 7. It The fixing pin 9 contacts the cam curved surface of the disc cam 5. By hand the disc cam 5 If it is gripped and rotated (see FIG. 5 (C)), the cam curved surface 5c can be rotated in accordance with the radial length. The disk cam 5 and the movable pedestal 3 that is integrally formed with the disk cam 5 move, and the movable pedestal 3 is long. It will move a distance δ along the longitudinal direction of the groove portions 3a, 3b, 3c.

[0022]   Two long groove portions 7a and 7b are stretched on the fixed base 7 and are attached to the base 1. It slides on the guide pins 1a and 1b provided, and after adjusting the movement in the longitudinal direction, it is fixed to the base 1. Is determined.

[0023]   The transmission wire W wound around the drum pulley 4 a plurality of times is the idle pulley 22A. , 22B, 22C and a tension spring 23 are wound and stretched, and both ends thereof are A V-mirror mount that holds a V-mirror consisting of a fourth mirror 17A and a fifth mirror 17B. The first slide 17D of the large slide unit) 17C is locked. The V mirror mount 17C The bearing portion at one end is movably held by the guide shaft 24, and the roller at the other end is a guide groove ( It is rotatably supported by (not shown) and can move freely back and forth in the direction parallel to the optical axis. is set up.

[0024]   On the other hand, the lens mount 28 that holds the main lens 16 has a guide shaft 27 at one end and The end is held in a guide groove (not shown) and is movable in the optical axis direction. other The timing pulley TP3, which is directly connected to the drive source, is connected to the timing pulley TB2 via the timing belt TB2. Drive the pulleys TP4 and TP5, and further wind TP6 via the timing belt TB3. After that, it is connected to the coupling portion 29 of the lens mount 28 and moved by a predetermined amount.

[0025]   In such a configuration, when the drive motor M1 rotates, the drive timing pool By the timing belt TB hanging on the TP1, the timing pulley TP1 and the drum The pulley 4 rotates. The rotational force of the drum pulley 4 is V It is transmitted to the mirror mount 17C. At the same time, the disc cam 5 is adjusted to the drum pulley 4 and then fixed. Since it is installed, it rotates while contacting the fixed pin 9. At this time, the disk cam 5 The movable pedestal 3 follows the movement direction regulating pins 3A, 3B, 3C only by the phase difference generated as a result. To move. Here, the tension spring 23 changes in environment such as temperature change, durability change over time. It is provided in consideration of. The guide pins 1a and 1b of the fixed base 3 are V mirrors. It is provided for adjusting the initial position setting of the frame 17C.

[0026]   5 (A), (B) and (C) show a method of adjusting the disc cam 5.

[0027]   FIG. 5A shows the original position at the same size. Repeat this at maximum magnification (0.5x, 2x) The rotated one is shown in FIG. 5 (B). Here, the best focus position is displaced due to the influence of the aberration. As shown in FIG. 5 (C), the disk cam 5 is used as a means for correcting a large amount in the original use angle range. The parts other than have a linear cam curve, and the position at maximum zoom is fixed to the disc cam. Loosen the screws 5d and 5e and rotate them by an external force. The rotation of the disc cam 5 is caused by the fixed pin. The movable frame (V mirror correction table) 3 is moved straight through the camera 9 and the V mirror is moved. -Move the gantry 17C back and forth as described above. In this way, 11 When the optimum image is obtained on the disk 11, use the fixing screws 5d and 5e to move the disk cam 5 Fix it to the drum pulley 4. At this time, the origin in the same size also moves, but the If the radius is set to the same radius, there will be no change in the position of the V mirror mount 17C at the same size position. .

[0028]   Further, in the above embodiment, the arrangement of the V mirrors 17A and 17B at the time of enlargement / reduction is the same cam. The reason for this is explained in relation to the depth of focus.

[0029]   The depth of focus is calculated by (Equation-1). Here, the magnification is doubled on the enlargement side and reduced It can be seen that the magnified focal depth is deep as shown below (when the magnification is 0.5 times). Therefore By performing correction adjustment on the reduction side, the performance on the enlargement side is also fully satisfied. .

[0030]               (Depth of focus) = F value × (1 + M) / R ... (Equation-1)   Here, M is the enlargement / reduction ratio, and R is the required resolution (lines / mm).

[0031]   Now, when using the main lens with R = 10 (lines / mm) and F value = 10,   If M = 1 (equal magnification), the depth of focus is 1.0 mm   If M = 2 (double magnification), the depth of focus is 1.5mm   If M = 0.5 (0.5x reduction), the depth of focus is 0.5mm   However, if an extremely bright F-number lens and high resolution are required, use a disc Rotate the cam 5 forward / backward, and on the reduction / enlargement side, the V mirror mount 17 It can be easily inferred from the present invention that it becomes a mechanism for adjusting C.

[0032]   FIG. 6 is a plan view showing a V mirror mount moving device according to another embodiment of the present invention. It is to be noted that, regarding the reference numerals used in the drawings, parts having the same functions as those in the above embodiment Are attached with the same numbers. Further, the points different from the above embodiment will be described.

[0033]   In this embodiment, the drive motor M1 is mounted on the motor mount 2. Further, it is fixedly installed on the fixed base 7. Furthermore, the timing of the drive motor M1 Timing pulley TP2 coaxial with the pulley TP1 and the disk cam 5 installed on the movable mount 3. To the timing belt TB via the tension pulley 26 which is biased by the spring. More connected. The tension pulley 26 has an oscillating movable center around a fulcrum 26A. It is rotatably supported at one end of the arm 26B. If you pull on the other end of the arm 26B 26C is locked, the arm 26B is spring-biased in one direction, and the timing belt TB is always I'm nervous.

[0034]   In this embodiment, since the heavy motor M1 is not mounted on the movable mount 3, The motor load such as moving the movable platform is small, and it can be operated reliably by the low torque motor. You can

[0035]   7A and 7B are plan views showing a method for adjusting the rotation of the disc cam 5.

[0036]   By adjusting the rotation of the disc cam 5, the movable mount 3 can be moved by the maximum displacement amount δ. . Further, by adjusting the rotation of the disk cam 5, the V mirror mount 17C is transferred through the transmission wire W. Is moved and corrected by a predetermined amount.

[0037]   In the structure as described above, the lens mount (lens slide unit) 28, The positional relationship between the V mirror mount (mirror slide unit) 17C and the sixth mirror 18 is , Greatly affect the optical performance. Therefore, the position of the substrate 1 that determines these positions is Flatness and degree are important factors.

[0038]   FIG. 10 is a front view showing the shape of a conventional substrate.

[0039]   The four sides of the base 1 are bent with the four corners open. And, two opposite sides 1d , 1e has a shaft 27 fastened thereto. In this configuration, the bottom surface of the substrate 1 is Fixed stand 7, drive source (stepping motor) M1, position sensor 19, sixth mirror 18 (all not shown) are fixedly mounted, and a lens mount 28 (both not shown) is attached to the shaft 27. ) Is engaged.

[0040]   The base body 1 is formed of a thin steel plate that can be press-cut and bent, and its thickness is , 1.5-2 mm is generally used.

[0041]   Therefore, the conventional base body 1 needs to have a sufficiently thick plate thickness in order to maintain flatness and strength. In addition to the above, the unit and mirror are The work was inefficient due to the fine adjustment.

[0042]   Further, in order to make up for this drawback, the base body 1 is formed by casting, and the optical member mounting surface is formed. Is used as a machined surface, or is formed by die casting, but it is expensive. Not only that, but there was a drawback that the weight became heavy.

[0043]   Image of the present invention Formed by inexpensive press cutting and bending with the taking optical system variable magnification device Even if the plate thickness is thin, it can be filled by using a bent base and devising the structure of the bent part. It is possible to maintain sufficient flatness and strength.

[0044]   FIG. 8 is a perspective view of the base body 1 according to the present invention, and FIG.

[0045]   The bent portions 1d and 1e on the two opposite sides of the base body 1 are folded on the two sides whose end faces are adjacent to each other. The flat portions of the bent portions 1f and 1g are in contact with each other. Furthermore, on the opposite two sides 1d and 1e The guide shaft 27 is connected and screwed. In this configuration, the bottom of the base 1 A fixed mount 7, a drive source (stepping motor) M1, a position sensor 19, A sixth mirror 18 (all not shown) is fixedly installed, and the guide shafts 27, 24 are provided with a lens. The lens mount 28 and the V-mirror mount 17C (both not shown) are engaged.

[0046]   In addition, the bottomed rib groove 1C formed in the bottom plate portion of the base 1 has an H shape, It is drawn to reinforce the bottom plate. With such a structure, the substrate 1 and the flatness are improved. In addition, the thickness of the base 1 should be 1.2 mm or less. Even if it is thin, it will have sufficient flatness (flatness 0.1) and strength as the main body of the optical system of the copying machine. I was able to. This makes it possible to reduce the weight and cost of the optical device, and Surface quality and strength performance have been obtained that are equal to or better than conventional ones.

[0047]

[Effect of device]

  By the variable magnification device of the image reading optical system according to the present invention,   If the cam shape is a disk cam, and the movable mount having the disk cam has a correction amount Since it only moves within the range of the The knit can be arranged without waste, and it has become compact.

[0048]   Only the magnification range that needs correction can be adjusted, so if the adjustment work is easy Highly accurate adjustment is now possible.

[0049]   The main body of the device has been reduced in weight, cost, flatness, and strength.

[Brief description of drawings]

FIG. 1 is a block diagram of a copying machine according to the present invention.

FIG. 2 is a perspective view of a variable power device according to the present invention.

FIG. 3 is a front cross-sectional view of a V mirror unit gantry moving device.

FIG. 4 is a plan view of the moving device.

FIG. 5 is a plan view showing a method of adjusting a disc cam of the moving device.

FIG. 6 is a plan view of a V mirror mount moving device according to another embodiment of the present invention.

FIG. 7 is a plan view showing a method of adjusting a disc cam of the moving device.

FIG. 8 is a perspective view of a base body according to the present invention.

FIG. 9 is a front view of the base body.

FIG. 10 is a front view showing a conventional base body shape.

[Explanation of symbols]

1 base 2 Motor mount 3 Movable stand (V mirror correction stand) 4 drum pulley 5 disk cam 7 Fixed stand (V mirror correction stand) 9 fixing pin 10 Optical system 16 Main lens 17A 4th mirror 17B 5th mirror 17C V mirror mount 18 6th mirror 26 Tension pulley 28 lens mount M1 motor TB1, TB2, TB3 Timing belt TP1, TP2, TP3, TP4, TP5, TP6 Timing pulley W transmission wire

Claims (4)

[Scope of utility model registration request] 1. An optical system including a light source for exposing an original document, a zooming mirror arranged orthogonally to change an optical path, and a main lens, and the main lens and the zooming mirror are moved at a predetermined ratio. In a variable magnification device of an image reading optical system, which is configured by a drive system, and which changes the magnification by moving the lens and the variable magnification mirror along the optical axis of the optical system, a mount for holding the variable magnification mirror. A variable power device for an image reading optical system, which is equipped with a displacement amount correction mechanism for correcting the position when the power is changed. 2. The variable power device of the image reading optical system according to claim 1, wherein the displacement amount correction mechanism is composed of at least one disk cam and a fixed pin. 3. An optical system including an original exposure light source, a zooming mirror arranged orthogonally to change the optical path, and a main lens, and the main lens and the zooming mirror are moved at a predetermined ratio. In a variable magnification device of an image reading optical system, which is configured by a drive system, and which changes the magnification by moving the lens and the variable magnification mirror along the optical axis of the optical system, a mount for holding the variable magnification mirror. Displacement amount correction cam for correcting the position during zooming, a movable mount equipped with a drive source that moves the mirror holding mount according to the zooming value, a fixed pin that contacts the correction cam, and the movable mount. A variable magnification device for an image reading optical system, comprising: a fixed base provided with a restriction pin for restricting the movable direction of the optical axis, and a base for positioning and supporting the fixed base and the mirror holding base. 4. An optical system including a light source for exposing a document, a zooming mirror that is arranged orthogonally and converts an optical path, and a main lens, and the main lens and the zooming mirror are moved at a predetermined ratio. In a variable magnification device of an image reading optical system, which is configured by a drive system, and which changes the magnification by moving the lens and the variable magnification mirror along the optical axis of the optical system, a mount for holding the variable magnification mirror. Of the movable mount, which mounts a displacement correction cam that corrects the position during zooming, a fixing pin that abuts the correction cam, a drive source that moves the mirror holding mount according to the zooming value, and A variable magnification apparatus for an image reading optical system, comprising: a fixed base provided with a restriction pin for restricting a movable direction, and a base for fixing and supporting the fixed base and the mirror holding base.