JP4737244B2 - Optical scanning device - Google Patents

Description

  The present invention relates to an optical scanning device that reflects and deflects a light beam on both surfaces of a vibrating mirror.

  Conventionally, as an optical scanning device that scans a plurality of photosensitive drums with a light beam, a plurality of light sources, a vibrating mirror that reflects the light beam emitted from each light source on both sides, and each light reflected on both sides of the vibrating mirror A lens including a lens for guiding a beam to each photosensitive drum and a reflection mirror is known (see Patent Document 1). Further, in this technique, in order to determine the timing of writing by each light beam (flighting the light beam in accordance with image data to form an electrostatic latent image on the photosensitive drum), it corresponds to each photosensitive drum. A plurality of optical sensors are provided. As a result, after each light beam reflected on both surfaces of the vibrating mirror is detected by each light sensor, writing by each light beam is started at a predetermined timing from the detection by the light sensor, and the electrostatic latent image is satisfactorily formed on the photosensitive drum. Is to be formed.

JP 2006-292891 A

  However, the prior art has a problem in that the cost is increased because the same number of optical sensors as the number of photosensitive drums are provided. Further, in the structure in which a plurality of optical sensors are provided as described above, there is a problem that the control becomes complicated when the detection accuracy of each optical sensor is different due to a manufacturing error or the like.

  SUMMARY An advantage of some aspects of the invention is that it provides an optical scanning device capable of reducing cost and improving control by reducing the number of optical sensors.

  In order to solve the above problems, an optical scanning device according to the present invention includes a plurality of light sources and reflective surfaces formed on both front and back surfaces, and light beams emitted from the plurality of light sources are opposed to each other by the reflective surfaces on both front and back surfaces. And an oscillating mirror that deflects the light beam by oscillating the reflective surfaces on both the front and back surfaces, and the oscillating mirror when the oscillating mirror is oscillated in one direction. Guiding means for guiding the surface side light beam reflected by the surface of the light source and the back side light beam reflected by the back surface of the vibrating mirror to the predetermined position when the vibrating mirror swings to the other, and the predetermined position And a common optical sensor that detects both the light beams.

  According to the present invention, when the oscillating mirror swings to one side, the surface side light beam is detected by the optical sensor via the guiding means. Thereafter, when the oscillating mirror swings in the other direction, that is, when the oscillating mirror swings in one direction, the light beam on the back side is detected by the optical sensor via the guiding means. Accordingly, since the front side light beam and the back side light beam can be detected by a common optical sensor, the number of optical sensors can be reduced, and cost reduction and control improvement can be achieved.

  According to the present invention, since the front side light beam and the back side light beam can be detected by a common optical sensor, the number of optical sensors can be reduced, and cost reduction and control improvement can be achieved.

  Next, an embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In the drawings to be referred to, FIG. 1 is a plan view showing an optical scanning device according to an embodiment of the present invention, and FIG. 2 is a side view of FIG. 3 is a perspective view showing the structure around the optical sensor, and FIG. 4 is a plan view of FIG. FIG. 5 is a flowchart showing the operation of the control device.

  In the following description, the right side in FIG. 1 is referred to as “front (front)”, the left side as “rear (back)”, the upper side as “right”, and the lower side as “left” unless otherwise specified. Also, the front side with respect to the paper surface of FIG. 1 is referred to as “upper” and the rear side is referred to as “lower”. That is, each direction is defined with reference to a direction viewed from a person standing on the near side of the optical scanning device 1.

  As shown in FIG. 1, the optical scanning device 1 includes a laser light source 2, a vibrating mirror 3, an exposure optical system 4, a sensor optical system 5 as an example of guiding means, an optical sensor 6, and a control device 7. Has been.

  Four laser light sources 2 are provided corresponding to the four (plural) photosensitive drums 8 scanned by the optical scanning device 1. Specifically, the first laser light source 2A is disposed on the left side of the optical scanning device 1 corresponding to the first photosensitive drum 8A disposed on the rearmost side, and is disposed in front of the first photosensitive drum 8A. A second laser light source 2B is arranged on the left side of the optical scanning device 1 corresponding to the photosensitive drum 8B. A third laser light source 2C is disposed on the right side of the optical scanning device 1 in correspondence with the third photosensitive drum 8C disposed in front of the second photosensitive drum 8B, and is disposed in front of the third photosensitive drum 8C. A fourth laser light source 2D is arranged on the right side of the optical scanning device 1 corresponding to the four photosensitive drums 8D.

  The light beam (solid line) emitted from the first laser light source 2A passes through the half mirror 21, and then proceeds obliquely downward toward the surface 31 of the oscillating mirror 3 through a lens (not shown). A light beam (one-dot chain line) emitted from the second laser light source 2B is reflected by the half mirror 21, and then a lens (not shown) or the like below the light beam emitted from the first laser light source 2A. It proceeds in an obliquely upward direction toward the surface 31 of the oscillating mirror 3.

  Here, each light beam (solid line, one-dot chain line) is actually shifted up and down, but in FIG. Also, the respective light beams emitted from the third laser light source 2C and the fourth laser light source 2D are obliquely incident on the back surface 32 of the oscillating mirror 3 while being shifted in the vertical direction as described above.

  The oscillating mirror 3 is a double-sided mirror in which reflecting surfaces are formed on both the front surface 31 and the back surface 32, and light beams emitted from a plurality of laser light sources 2 are directed in opposite directions by the reflecting surfaces of the front surface 31 and the back surface 32. Reflected. The oscillating mirror 3 swings (rotates and oscillates) within a predetermined range by an electromagnetic drive system, whereby the light beam is swung to the left and right to pivot the light beam on each photosensitive drum 8. Reciprocate (scan) in the direction. In the following description, the light beam reflected by the surface 31 of the oscillating mirror 3 is also referred to as “front surface side light beam B1”, and the light beam reflected by the back surface 32 is also referred to as “back surface side light beam B2”.

  The exposure optical system 4 includes a plurality of fθ lenses 41, a reflection mirror 42, and a correction lens 43.

  The fθ lens 41 is a lens that corrects a light beam that moves at a speed according to a sine wave by the oscillation of the oscillating mirror 3 so as to move at a constant speed along the axial direction of the photosensitive drum 8 on the surface of the photosensitive drum 8. It is. One fθ lens 41 is provided before and after the vibrating mirror 3.

  The reflection mirror 42 is a mirror that reflects the light beam, and is appropriately disposed at a predetermined position so that the light beam emerging from the fθ lens 41 is directed to the correction lens 43 as shown in FIG.

  The correction lenses 43 are lenses for correcting the tilting of the vibrating mirror 3, and four correction lenses 43 are provided corresponding to the respective photosensitive drums 8.

  Then, each light beam deflected by the vibration mirror 3 is emitted to each photosensitive drum 8 through a path shown in FIG.

  As shown in FIG. 1, the sensor optical system 5 includes a front surface side reflection mirror 51, a back surface side reflection mirror 52, and a correction lens 53.

  The front-side reflecting mirror 51 is on the left side of the swinging range β of the front-side light beam B1 corresponding to the image forming range α on the photosensitive drum 8 and downstream of the fθ lens 41 (downstream in the traveling direction of the light beam). Side). Here, the “image formation range α” is the maximum width of an image formed on a sheet (not shown) (a width orthogonal to the sheet conveyance direction), and is a range in which the light beam is scanned on the photosensitive drum 8 while blinking. Say.

  Further, as shown in FIG. 2, the front-side reflecting mirror 51 is a light beam (light emitted from the first laser light source 2A) traveling obliquely downward of the two light beams reflected by the surface 31 of the vibrating mirror 3. Beam). As a result, as shown in FIG. 1, the surface-side reflecting mirror 51 has the surface 31 of the oscillating mirror 3 when the oscillating mirror 3 oscillates in one direction (position in FIG. 1; the surface 31 faces diagonally to the left). The surface-side light beam B1 swung leftward (predetermined direction) is reflected (guided) toward a predetermined position.

  The rear surface side reflection mirror 52 is disposed at the same position as the front surface side reflection mirror 51, that is, at a position symmetrical with the front surface side reflection mirror 51 with respect to the swing center CP of the vibration mirror 3. In other words, with respect to the surface including the oscillation center CP of the oscillating mirror 3 parallel to the stationary surface of the oscillating mirror 3 (surface orthogonal to the front-rear direction), the front-side reflecting mirror 51 and the back-side reflecting mirror 52 are They are arranged at plane-symmetric positions in plan view. Further, as shown in FIG. 2, the back surface side reflecting mirror 52 is a light beam (light emitted from the fourth laser light source 2D) traveling obliquely upward of the two light beams reflected by the back surface 32 of the vibrating mirror 3. Beam).

  As a result, as shown in FIG. 1, the back-side reflecting mirror 52 vibrates when the oscillating mirror 3 swings to the other side (position approximately in phase opposite to that in FIG. 1; the back surface 32 faces diagonally to the left). The back surface side light beam B2 swung leftward (predetermined direction) by the back surface 32 of the mirror 3 is reflected (guided) toward a predetermined position.

  The correction lens 53 is a lens having the same function as that of the correction lens 43 of the exposure optical system 4, and is arranged one by one on the downstream side of the front surface side reflection mirror 51 and the back surface side reflection mirror 52.

  The optical sensor 6 is disposed at the predetermined position, and detects both the front surface side light beam B1 and the back surface side light beam B2. The optical sensor 6 outputs a signal corresponding to the detection of light to the control device 7. As shown in FIG. 3, a front side substrate 61 and a back side substrate 62 are provided on the light beam incident side of the optical sensor 6.

  On the front side substrate 61 and the back side substrate 62, slits 61A and 62A for passing the respective light beams B1 and B2 are formed, respectively. Specifically, each of the slits 61A and 62A is formed such that the horizontal width (the width in the oscillation direction of the light beam) is narrower than the vertical width and slightly larger than the diameter of the light beams B1 and B2.

  Then, as shown in FIG. 4, the front side substrate 61 and the back side substrate 62 are arranged (adjusted) at different positions in the swing direction of the light beams B1 and B2. That is, the slit 61A of the front surface side substrate 61 is disposed at a position shifted by an angle X from the front surface side light beam B1 (B11 in FIG. 4) swung to the left (see FIG. 1). 62A is arranged at a position shifted by an angle Y larger than the angle X from the back side light beam B2 (B21 in FIG. 4) swung to the left (see FIG. 1).

  As a result, the surface detection time T1 (see FIG. 6) from when the front side light beam B1 enters the optical sensor 6 through the slit 61A until it enters again, and the rear side light beam B2 passes through the slit 62A. There is a difference between the back surface detection time T2 (see FIG. 6) from when it enters the optical sensor 6 until it enters again. That is, the time T1 between the two pulse signals P11 and P12 output from the optical sensor 6 to the control device 7 when the direction in which the surface side light beam B1 is swung is switched from left to right is a small angle X (see FIG. 4), the time is relatively short. On the other hand, when the direction in which the back side light beam B2 is swung is switched from left to right, the time T2 between the two pulse signals P21 and P22 output from the optical sensor 6 to the control device 7 is determined from the angle X. Corresponding to a larger angle Y, the time is longer than the time T1.

  As shown in FIG. 1, the control device 7 has a function of controlling each laser light source 2 based on a signal output from the optical sensor 6. Specifically, the control is executed according to the flowchart shown in FIG. The control device 7 also performs vibration control of the vibration mirror 3 and the like.

  As shown in FIG. 5, the control device 7 first determines whether or not a light beam is detected by the optical sensor 6 (S1). If it is determined in step S1 that the light beam is not detected (No), the control device 7 returns to the process of step S1 again.

  If it is determined in step S1 that a light beam has been detected (Yes), the control device 7 determines whether or not the time between two pulse signals output from the optical sensor 6 is the surface detection time T1. Thus, it is determined whether or not the detected light beam is the front side light beam B1 (S2). When it is determined in step S2 that the light beam is the front side light beam B1 (Yes), the control device 7 determines whether or not a predetermined time T3 (see FIG. 6) has passed (S3).

  If it is determined in step S2 that it is not the front side light beam B1 (No), the control device 7 determines whether or not a predetermined time T4 (see FIG. 6) shorter than the predetermined time T3 has elapsed. (S4). If it is determined in steps S3 and S4 that the predetermined times T3 and T4 have elapsed (Yes), the control device 7 causes each laser light source 2 to blink according to the image data (S5), and then performs this control. Exit.

  Next, the operation of the optical scanning device 1 will be described. In the drawings to be referred to, FIG. 6 shows a time chart (a) showing the state of the front side light beam, a time chart (b) showing the state of the back side light beam, and the detection state and printing by the optical sensor in the control device. It is a time chart (c) which shows the state of control. 7 is an explanatory diagram (a) to (c) showing the printing control after the front side light beam is detected, and FIG. 8 is an explanatory diagram showing the printing control after the back side light beam is detected. (A) to (c).

  In FIG. 6C, for the sake of convenience, the forward direction writing and the backward direction writing simultaneously performed are shown as being shifted left and right and up and down. 7 and 8, for convenience, the relationship between each of the light beams B1 and B2 and the first and fourth photosensitive drums 8A and 8D is simplified, and the other photosensitive drums 8B and 8C and the exposure drums are exposed. The optical system 4 and the like are omitted.

  As shown in FIG. 7A, when the surface side light beam B1 is swung to the left by the vibration mirror 3 swinging counterclockwise and reflected by the surface side reflection mirror 51, the reflected surface is reflected. The side light beam B1 is detected by the optical sensor 6. Thereafter, when the swinging direction of the surface-side light beam B1 is switched from left to right and the surface-side light beam B1 is detected again by the optical sensor 6, as shown in FIG. The pulse signals P11 and P12 are output at a short time interval T1.

  Then, as shown in FIG. 6C, the control device 7 determines that the light beam detected by the optical sensor 6 is the surface-side light beam B1 based on the interval T1 between the two pulse signals P11 and P12. . Thereafter, the control device 7 starts writing in the forward direction by the surface side light beam B1 at a predetermined timing (time t2: after time T3) from the time when the second pulse signal P12 is received (time t1) (in the drawing). (Shaded portion) and writing in the backward direction by the back side light beam B2 (dot portion in the figure) are started simultaneously. That is, as shown in FIG. 7B, the control device 7 blinks the laser light sources 2A and 2D on the basis of the image data, and swings the front side light beam B1 in the forward direction (right) and also on the back side. Shake the light beam B2 in the backward direction (left).

  Here, “writing with a light beam” means that the light beam is blinked according to image data to form an electrostatic latent image on the photosensitive drum 8. Further, the “forward direction” refers to one direction in the main scanning direction (paper width direction), and the “return direction” refers to a direction opposite to the forward direction.

  Then, as shown in FIG. 7C, after the surface-side light beam B1 is swung by the swinging range β corresponding to the image forming range α (after the vibrating mirror 3 is substantially in phase), The formation (flashing) of the electrostatic latent image by the light beams B1 and B2 is terminated. As a result, an electrostatic latent image based on the image data is formed in the image forming range α on each of the photosensitive drums 8A and 8D. The laser light sources 2B and 2C (not shown) are also controlled at the same timing as described above, whereby the photosensitive drums 8B and 8C are also written out by the light beam and are within the image forming range α. Thus, an electrostatic latent image is formed satisfactorily.

  Thereafter, as shown in FIG. 8A, when the back side light beam B2 swayed in the return direction is reflected by the back side reflecting mirror 52 and detected by the optical sensor 6, it is shown in FIG. 6B. Thus, the two pulse signals P21 and P22 are output from the optical sensor 6 at a time interval T2 longer than the time T1.

  Then, as shown in FIG. 6C, the control device 7 determines that the light beam detected by the optical sensor 6 is the back surface side light beam B2 based on the interval T2 between the two pulse signals P21 and P22. Thereafter, the control device 7 starts writing in the backward direction by the surface side light beam B1 at a predetermined timing (time t4: after time T4) from the time when the second pulse signal P22 is received (time t3) (in the drawing). (Dot portion) is started and writing in the forward direction by the back side light beam B2 (shaded portion in the figure) is started.

  Thereafter, as described above, as shown in FIGS. 8B to 8C, the front side light beam B1 is shaken in the backward direction by the oscillation range β and the back side light beam B2 is shaken in the forward direction. Each of the laser light sources 2A and 2D (same as 2B and 2C) is flickered while being shaken by the moving range β, thereby electrostatically entering the image forming range α on each photosensitive drum 8A and 8D (same as 8B and 8C). A latent image is formed.

According to the above, the following effects can be obtained in the present embodiment.
Since the front side light beam B1 and the back side light beam B2 can be detected by the common optical sensor 6, the number of optical sensors can be reduced, and the cost can be reduced and the control can be improved.

  Of the two light beams B1 and B2 deflected by the front surface 31 and the rear surface 32 of the vibration mirror 3, one light beam B1 and B2 is applied to the optical sensor 6 by the front surface side reflection mirror 51 or the rear surface side reflection mirror 52. Therefore, the number of parts is reduced compared to the structure in which all four light beams B1 and B2 are guided to the optical sensor 6, and the cost can be reduced. That is, one of the four light beams is detected and the timing of writing the four light beams is determined, so that only one optical sensor 6 is required, and the structure is simplified. be able to.

  Since the front-side reflection mirror 51 and the back-side reflection mirror 52 are moved to the optical sensor 6 side (left side), the sensor optical system 5 can be reduced in size, and thus the optical scanning device 1 can be reduced in size.

  At a predetermined timing from when the front side light beam B1 is detected by the optical sensor 6, writing in the forward direction by the front side light beam B1 and writing in the backward direction by the back side light beam B2 are started, At a predetermined timing from when the beam B2 is detected by the optical sensor 6, writing in the backward direction by the front side light beam B1 and writing in the forward direction by the back side light beam B2 are started. Writing by B2 can be performed efficiently.

  The surface detection time T1 from when the front surface side light beam B1 is incident on the optical sensor 6 until it is incident again, and the rear surface detection time T2 from when the rear surface side light beam B2 is incident on the optical sensor 6 until it is incident again. Therefore, the control device 7 can easily determine whether the light beam detected by the optical sensor 6 is reflected by the surface 31.

  Since the front-side substrate 61 and the back-side substrate 62 are arranged on the light beam incident side of the optical sensor 6, each substrate 61 is moved without moving the sensor optical system 5 (the front-side reflecting mirror 51, the back-side reflecting mirror 52, etc.). , 62 can be easily adjusted in the direction of the width of the light beam, and the difference between the front surface detection time T1 and the back surface detection time T2 can be easily provided.

In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below.
In the above embodiment, the front surface side substrate 61 and the back surface side substrate 62 are adjusted in the light beam swing width direction to provide a difference between the front surface detection time T1 and the back surface detection time T2, but the present invention is not limited to this. It is not something. For example, as shown in FIG. 9, a difference is provided between the front surface detection time T1 and the back surface detection time T2 by adjusting (shifting) the front surface side reflection mirror 51 and the rear surface side reflection mirror 52 in the light beam amplitude direction. May be. In this case, since it is not necessary to provide the front surface side substrate 61 and the back surface side substrate 62 as in the above embodiment, the number of components can be reduced.

  In the above embodiment, the photosensitive drums 8A and 8B are scanned (written) in the forward direction by the front side light beam B1, and the photosensitive drums 8C and 8D are scanned in the backward direction by the back side light beam B2. If configured, the following problems may occur. That is, since the rotation directions of the photosensitive drums 8 are the same, if the scanning directions of the photosensitive drums 8A and 8B on the front surface 31 side and the photosensitive drums 8C and 8D on the rear surface 32 side of the vibrating mirror 3 are reversed, FIG. As shown in (a), the scanning direction (solid line / broken line) on the photosensitive drums 8A, 8B and the scanning direction (one-dot chain line / two-dot chain line) on the photosensitive drums 8C, 8D intersect on the paper P. As a result, when printing on the paper P by each photosensitive drum 8, there is a possibility that the linear toner images of the respective colors intersect and mix colors.

  Therefore, as shown in FIG. 10B, it is desirable to align the scanning direction in each photosensitive drum 8 in the same direction. In order to make the scanning direction the same, the writing timing of the front side light beam B1 and the rear side light beam B2 may be shifted by a half period.

  Specifically, for example, as shown in FIGS. 11A to 11C, when the front side light beam B1 is detected by the optical sensor 6, only the front side light beam B1 is used to move to the photosensitive drums 8A and 8B. When the back side light beam B2 is detected by the optical sensor 6, writing to the photosensitive drums 8C and 8D may be performed using only the back side light beam B2. That is, when the front-side light beam B1 is detected by the optical sensor 6, the emission of the rear-side light beam B2 is stopped, and when the rear-side light beam B2 is detected by the optical sensor 6, the front-side light beam B1 What is necessary is just to stop emission. According to this, the scanning direction on each photosensitive drum 8 can be aligned with the forward direction (or the backward direction).

  Further, even if the scanning directions on the respective photosensitive drums 8 are not aligned, by adjusting the position of each photosensitive drum 8 and the position of each part of the exposure optical system 4, as shown in FIG. Each scanning direction may be aligned on P. That is, the timing for transferring the toner image from the photosensitive drums 8A and 8B on the front surface 31 side to the paper P and the timing for transferring the toner image from the photosensitive drums 8C and 8D on the back surface 32 side to the paper P may be shifted by a half cycle. Good.

  In the above-described embodiment, the front-side reflecting mirror 51 and the back-side reflecting mirror 52 are provided on the left side (the optical sensor 6 side) with respect to the vibrating mirror 3, but the present invention is not limited to this, and the right side ( It may be provided on the side opposite to the optical sensor 6.

In the embodiment, the correction lens 53 is provided on the downstream side of the front-side reflection mirror 51 or the back-side reflection mirror 52, but the present invention is not limited to this, and may be provided on the upstream side.
In the above-described embodiment, the guiding unit is configured by the front-side reflecting mirror 51, the back-side reflecting mirror 52, and the correction lens 53. However, the present invention is not limited to this, and for example, each of the reflecting mirrors 51 and 52 and the optical sensor 6 A plurality of reflection mirrors may be further provided therebetween.

1 is a plan view showing an optical scanning device according to an embodiment of the present invention. It is a side view of FIG. It is a perspective view which shows the structure around an optical sensor. FIG. 4 is a plan view of FIG. 3. It is a flowchart which shows operation | movement of a control apparatus. A time chart (a) showing the state of the front side light beam, a time chart (b) showing the state of the back side light beam, and a time chart (c) showing the detection state by the optical sensor in the control device and the state of print control. ). It is explanatory drawing (a)-(c) which shows the printing control after a surface side light beam is detected. It is explanatory drawing (a)-(c) which shows the printing control after a back surface side light beam is detected. It is a top view which shows the form which shifted the back surface side reflective mirror. A plan view (a) showing a printing state when the scanning directions of the front side light beam and the rear side light beam are reversed, and printing when the scanning directions of the front side light beam and the rear side light beam are aligned in the same direction. FIG. 6 is a plan view (b) showing a state and a plan view (c) showing a printing state when the printing timing from each photosensitive drum is changed. It is a figure which shows the form which shifted the writing timing of the surface side light beam and the back surface side light beam by a half cycle, the time chart (a) which shows the state of a surface side light beam, and the time which shows the state of a back surface side light beam It is a time chart (c) which shows a chart (b) and the detection state in the optical sensor in a control apparatus, and the state of printing control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical scanning device 2 Laser light source 3 Vibration mirror 4 Exposure optical system 5 Sensor optical system 6 Optical sensor 7 Control apparatus 31 Front surface 32 Back surface 51 Front surface side reflective mirror 52 Back surface side reflective mirror 53 Correction lens 61 Front surface side substrate 61A Slit 62 Back side substrate 62A Slit B1 Front side light beam B2 Back side light beam P11 Pulse signal P12 Pulse signal P21 Pulse signal P22 Pulse signal T1 Surface detection time T2 Back side detection time

Claims (8)

Multiple light sources;
Reflecting surfaces are formed on both front and back surfaces, and the light beams emitted from the plurality of light sources are reflected in opposite directions by the reflecting surfaces on the front and back surfaces, and the light beams are oscillated by swinging the reflecting surfaces on the front and back surfaces. In an optical scanning device comprising a vibrating mirror for deflecting
A surface-side light beam reflected on the surface of the vibrating mirror when the vibrating mirror swings to one side, and a back-side light beam reflected on the back surface of the vibrating mirror when the vibrating mirror swings to the other side Guiding means for guiding
An optical scanning device further comprising: a common optical sensor disposed at the predetermined position and detecting both the light beams. Four of the light sources are provided,
A light beam is emitted from two of the four light sources toward the surface of the vibrating mirror, and a light beam is emitted from the remaining two light sources toward the back of the vibrating mirror, respectively.
2. The optical scanning according to claim 1, wherein one of the two light beams deflected on the front surface and the back surface of the vibrating mirror is guided to the optical sensor by the guiding means. apparatus. The guiding means includes
A surface-side reflecting mirror that reflects the surface-side light beam toward the predetermined position;
The optical scanning device according to claim 2, further comprising: a rear surface side reflection mirror that reflects the rear surface side light beam toward the predetermined position. Start writing in the forward direction by the front side light beam and starting writing in the backward direction by the back side light beam at a predetermined timing from when the front side light beam is detected by the optical sensor. ,
At the predetermined timing from when the back side light beam is detected by the optical sensor, writing in the backward direction by the front side light beam is started and writing in the forward direction by the back side light beam is started. The optical scanning device according to claim 3, further comprising a control device.   The surface detection time from when the front side light beam is incident on the optical sensor until it is incident again, and the rear surface detection time from when the rear surface side light beam is incident on the optical sensor until it is incident again The optical scanning device according to claim 3, wherein a difference is provided. On the incident side of the light beam of the optical sensor,
A surface-side substrate on which a slit for passing the surface-side light beam is formed;
A back side substrate on which a slit for passing the back side light beam is formed, and
The difference between the front surface detection time and the back surface detection time is provided by adjusting the positions of the front surface side substrate and the back surface side substrate in the width direction of the light beam. Optical scanning device.   The difference between the front surface detection time and the back surface detection time is provided by adjusting the positions of the front surface side reflection mirror and the back surface side reflection mirror in the amplitude direction of the light beam. 5. The optical scanning device according to 5. The front surface side reflection mirror and the back surface side reflection mirror are:
4. The optical scanning device according to claim 3, wherein the optical scanning device is disposed in a plane-symmetrical position with respect to a plane including a center of oscillation of the oscillating mirror parallel to a stationary surface of the oscillating mirror.

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