JP2011043693A - Optical scanner and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanner which is made compact and in which an optical adjustment is easy, and to provide an image forming apparatus using the optical scanner. <P>SOLUTION: The optical scanner includes: a light source means which emits light beams 201A to 201D; an oscillation mirror 106 which has a deflection face which deflects the light beams to scan a main scanning region; an incident mirror part 110a which reflects the light beams 201A to 201D emitted from the light source means and makes the light beams incident on the deflection face of the oscillation mirror 106; an incident separation mirror 110 with which a separation mirror part 110b is integrated as a unit, which reflects and folds the light beams 201A, 201B deflected with the oscillation mirror 106 into one direction, and reflects and folds the rest of the light beams 201C, 201D into the other direction opposite to the folded direction of the light beams 201A, 201B; and a scanning and imaging optical system which guides the light beams from the separation mirror part 110b onto a face to be scanned, wherein the light beams 201A to 201D are reflected on the incident mirror part 110a at angles different from each other and made diagonally incident on the deflection face of the oscillation mirror 106. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical scanning device and an image forming apparatus, and in particular, an optical scanning device that scans a scanned surface with a plurality of light beams emitted from a light source unit, and an incident mirror that causes the light beams from each light source to enter a deflecting surface; The present invention relates to forming a separation mirror that is folded back in opposite directions.

  In an image forming apparatus such as a color copying machine or a color printer, a color image is formed by sequentially transferring images onto a plurality of image carriers aligned in parallel in the moving direction of a transfer medium such as a recording paper or an intermediate transfer belt. A tandem type color image forming apparatus is widely known.

  In the optical scanning device of the image forming apparatus, a polygon mirror or a galvanometer mirror is widely used as a deflection unit. However, in order to realize high-speed printing with higher resolution, the rotation speed of the deflector must be further increased. Problems such as bearing durability, heat generation, noise, and increased power consumption occurred, and there was a limit to speeding up.

  Here, for example, a vibrating mirror having a resonance structure in which a vibrating mirror using a silicon substrate and a torsion beam are integrally formed using the MEMS technology has been developed (Patent Documents 1 and 2).

  If this oscillating mirror is provided in place of the polygon mirror in the optical scanning device of the image forming apparatus, the device can be miniaturized and uses resonance, so the durability of high-speed scanning is good, and heat generation, noise, power consumption Can be significantly reduced (Patent Documents 3 and 4). In addition, the housing that houses the optical scanning device can be thinned due to low vibration and almost no heat generation, and even if low-cost resin molding material with a low glass fiber content is used, the image quality is affected. There is also an advantage that it is difficult.

However, in the vibrating mirror, there is a problem that the deflection angle changes due to a change in the spring constant of the torsion beam depending on the temperature or a change in the viscous resistance of the air due to the atmospheric pressure.
With respect to this problem, Patent Document 5 proposes a control that stably detects the deflection angle by detecting the scanned beam and adjusts the applied current applied to the oscillating mirror. Yes.

  By the way, in Cited Document 6, the optical scanning is provided with a separating polygon mirror which is a separating means for separating a plurality of light beams reflected by the light deflector corresponding to a plurality of photosensitive drums downstream from the light deflector. An apparatus is disclosed. In this invention, it is possible to shorten the distance from the separating means to the cylindrical mirror, which is the most downstream optical element of the optical scanning device, by providing the separating means and appropriately setting the arrangement position of the folding mirror.

However, in the invention described in the cited document 6, it is necessary to interpose an image forming means between the optical deflector and the separating means, and it is difficult to shorten the distance from the optical deflector to the separating means. There was a limit to miniaturization of the device. Further, the light source means is disposed on the opposite side of the optical deflector from the position of the separating means and the like, and the entire optical scanning device cannot be reduced in size.
Further, when it is attempted to secure the interval between the photosensitive drums, the angle between a plurality of light beams from the light source to the polygon mirror via the reflection mirror is increased, leading to an increase in the size of the apparatus.

  Further, if the light beams are separated due to the difference in the oblique incident angles of the light beams from the plurality of light sources in the sub-scanning direction, the optical path in the sub-scanning direction of the optical scanning device becomes very large, and the image forming optical system is replaced with another one. It becomes difficult in design to arrange with the scanning optical system.

  Further, when the deflection surface is arranged so as to be orthogonal to the optical axis in the conventional scanning direction, the light sources (light emitting portions) must be arranged in a line perpendicular to the scanning plane. The thickness of the apparatus was increased.

  The present invention has been made in view of the above-described problems in the prior art. An optical scanning device capable of downsizing the apparatus and easily optically adjusted, and an image forming apparatus using the optical scanning device are provided. The purpose is to provide.

The present invention provided to solve the above problems is as follows.
[1] Light source means (light source part 200) provided with light emitting parts (semiconductor lasers 200A to 200D) for emitting a plurality of light beams, light source driving means for modulating and driving the light source means, and light beams from the light source means And deflecting means (vibrating mirror 106) having a deflecting surface for deflecting in a specific direction while reflecting the light and scanning a specific area, and reflecting a plurality of light beams emitted from the light source means to the deflecting surface of the deflecting means An incident mirror part (incident mirror part 110a) to be incident and a plurality of light beams deflected by the deflecting means are reflected by reflecting one or several light beams in one direction, and the remaining light beams are reflected by the 1 Alternatively, an incident separation mirror (incident separation mirror) integrated with a separation mirror portion (separation mirror portion 110b) that reflects and folds back some light beams in the opposite direction. 110) and a scanning imaging optical system (folding mirrors 127 to 132, scanning lenses 122 to 125) for guiding the light beam from the separation mirror unit onto the surface to be scanned, and the plurality of light beams are An optical scanning device (optical scanning device 100, FIG. 4), which is reflected by an incident mirror section at different angles and obliquely incident on the deflection surface of the deflecting means.
[2] The deflection unit is a vibrating mirror that is supported by a torsion beam having a deflection surface serving as a rotation axis and deflects a light beam from the light source unit to scan a specific area. ] The optical scanning device described in the above.
[3] The optical scanning device according to [1] or [2] (FIG. 8), wherein the separation mirror section has reflecting surfaces having different angles corresponding to the plurality of light beams.
[4] A housing (housing 100B) that integrally supports at least the light source unit and the deflecting unit is provided, and the incident separation mirror has a predetermined positional relationship with the light source unit and the deflecting unit in the housing. The optical scanning device according to any one of [1] to [3] (FIG. 9 to FIG. 11), further comprising positioning means (positioning means 110c).
[5] The positioning means positions the incident separation mirror in a plane orthogonal to the rotation axis of the deflection means of the housing, and sets the position of the incident mirror portion with respect to the deflection surface of the deflection means. 9. The optical scanning device according to [4] above (FIG. 9).
[6] In the above [4], the positioning means positions the height of the incident separation mirror in the housing and sets the position of the separation mirror portion with respect to the deflection surface of the deflection means. Alternatively, the optical scanning device according to [5] (FIG. 10).
[7] The positioning means positions the incident separation mirror in a plane parallel to the rotation axis of the deflection means of the housing, and sets the position of the separation mirror portion with respect to the deflection surface of the deflection means. The optical scanning device according to any one of [4] to [6] (FIG. 11).
[8] The optical scanning device according to any one of [1] to [7], and a plurality of image carriers that are scanned with a light beam including image information from the optical scanning device. An image forming apparatus (FIG. 12).

According to the optical scanning device of the present invention, since the incident mirror and the separation mirror are integrally formed, each light emitting portion can be arranged in parallel to the scanning plane, and the thickness of the optical scanning device can be reduced. Can be thinned. In addition, since the incident separation mirror in which the incident mirror and the separation mirror are integrated can be arranged close to the deflecting surface of the deflector, the scanning width of the light beam in the separation mirror portion is shortened, and the reflecting surface of the separation mirror portion The width in the main scanning direction can be shortened, and the size of the incident separation mirror can be reduced. Further, since the effective width of the reflecting surface can be shortened as compared with the conventional case, the processing of the reflecting surface is facilitated and the processing accuracy can be increased.
According to the image forming apparatus of the present invention, the light source is arranged on the main scanning plane without using the light scanning device in the thickness direction as in the prior art by using the optical scanning device having the integrated incident separation mirror. Therefore, the thickness of the optical scanning device can be reduced and the device can be miniaturized. Also, the integrated incident separation mirror reduces the assembly adjustment process, reduces the size of the incident separation mirror, and increases the reflection surface. Accuracy can be improved and a high-quality output image can be formed.

It is a perspective view which shows the basic composition used as the premise of the optical scanning device concerning this invention. FIG. 2 is an optical path diagram downstream from a deflector viewed from an observation point P in the optical scanning device of FIG. 1. FIG. 2 is an optical path diagram from a light source unit to a separation unit viewed from an observation point Q in the optical scanning device of FIG. 1. It is a perspective view which shows the structure of the optical scanning device based on this invention. It is a perspective view which shows the structure of the incident separation mirror used by this invention. FIG. 6 is a cross-sectional view illustrating a separation state when light beams are incident on the separation mirror portion of the incident separation mirror in FIG. 5 in a parallel state. It is sectional drawing which shows the separation state of the light beam by the isolation | separation mirror part at the time of making a light beam incident on the deflection | deviation surface of a vibration mirror obliquely. FIG. 6 is a cross-sectional view showing a separation state when the reflection angle at the separation mirror portion of the incident separation mirror in FIG. 5 differs for each light beam. It is the schematic which shows the positioning adjustment method in yz plane of the incident separation mirror by a positioning means. It is the schematic which shows the positioning adjustment method of the z direction of the incident separation mirror by a positioning means. It is the schematic which shows the positioning adjustment method in xz plane of the incident separation mirror by a positioning means. 1 is a cross-sectional view illustrating a configuration of an image forming apparatus according to the present invention.

First, a configuration that is a premise of the optical scanning device according to the present invention will be described.
FIG. 1 is a perspective view showing a basic configuration of an optical scanning apparatus that scans four stations using a vibrating mirror (also referred to as a vibrating mirror module or micromirror) using a resonance phenomenon as an optical deflector. 1 shows an optical path diagram downstream from the deflector as viewed from the observation point P, and FIG. 3 shows an optical path diagram from the light source means 200 to the separation means 112 as viewed from the observation point Q.

  As shown in FIG. 1, the optical scanning device that scans each photosensitive drum is integrally formed, and four photosensitive drums 101A and 101B are arranged at equal intervals along the moving direction of a transfer body (not shown). , 101C and 101D, the light beams from the corresponding light sources are deflected again in the main scanning direction (y direction) by the oscillating mirror 106 and then separated again to guide the four photosensitive drums in the sub scanning direction ( A two-dimensional image is formed by rotating in the x direction.

  Here, the light source unit 200 is a light source unit having semiconductor lasers 200A, 200B, 200C, and 200D, which are four light emitting units arranged in the sub-scanning direction, and the light beams 201A to 200A to 200D are emitted from the semiconductor lasers 200A to 200D. 201D is obliquely incident on the oscillating mirror 106 at different incident angles in the x direction, so that the light beams from the respective semiconductor lasers 200A to 200D are deflected and scanned collectively. The oscillating mirror 106 is a resonance in which a oscillating mirror (deflection surface) whose longitudinal direction is the main scanning direction and a torsion beam that supports the central portion of the oscillating mirror and extends in the sub-scanning direction are integrally formed on the silicon substrate. This is a vibrating mirror module having a structure and used as an optical deflector.

  In the present optical scanning device, a plurality of scanning regions are scanned by a single vibrating mirror 106, so that the cost can be reduced and the resonance frequency and the driving frequency that are indispensable when using a plurality of vibrating mirrors are used. This eliminates the need to adjust the amplitude and deflection angle, shortens the manufacturing process, and improves the optical performance. In addition, each light beam can be easily separated to reduce the size of the entire apparatus.

  The respective light beams 201A to 201D emitted from the respective semiconductor lasers 200A to 200D are converted into parallel beams by the collimator lens group 104, and then converged in the sub-scanning direction near the reflecting surface of the vibrating mirror 106 by the cylindrical lens group 113, respectively. Then, it is reflected by the incident mirror 111 and guided to the deflection surface of the vibrating mirror 106. Next, the light beams 201 </ b> A to 201 </ b> D are deflected while being reflected by the deflection surface of the vibrating mirror 106 and scanned in the main scanning region. After the deflection, the light beams 201 </ b> A to 201 </ b> D are widened so that the light beams are separated from each other, and separated by the separation mirror 112 immediately after the deflection by the vibrating mirror 106.

  Here, the four light beams 201A to 201D are in one region (R in FIG. 2) with respect to a plane (O in FIG. 2) orthogonal to the rotation axis (A in FIG. 2) of the oscillating mirror 106. Are laid out so that they are separated into two in the other region (L in FIG. 2). In this way, by providing the separation mirror 112 after the optical deflector without using the imaging means to separate each light beam, the optical element at the most downstream position of the optical scanning device from the optical deflector (vibration mirror 106). In this embodiment, the thickness t up to the scanning lenses 122 to 125 which are individual imaging means can be shortened.

  Light beams 201A to 201D from the respective semiconductor lasers deflected and scanned by the vibrating mirror 106 are imaged in spots on the photosensitive drums 101A to 101D via the folding mirrors 127 to 132 and the scanning lenses 122 to 125, respectively. A latent image based on information is formed. In order to keep the scanning speed of the photosensitive drum uniform over the entire effective image area, the scanning lenses 122 to 125 have f · arcsin characteristics.

  The light beam deflected by the vibration mirror 106 is coupled to the synchronization detection sensor (also referred to as “PD (photodiode) for vibration control” or “synchronization detection”) 136 (−image height) and 138 (+ image height). The light is focused by the image lenses 137 and 139, and a synchronization detection signal for each station is generated based on the detection signal. The synchronization detection sensors 136 and 138 are light beam detection means for controlling the deflection means, and are optical sensors including a photodiode (PD) having a light receiving surface for detecting the passage of the light beam from the light source unit 200. is there.

  That is, in an optical scanning device having a light emission amount control period in which a semiconductor laser is forcibly turned off, a light beam emitted from a semiconductor laser (for example, a semiconductor laser 200A) pulse-driven by a light source driving unit is deflected and scanned by a vibrating mirror 106. When the light beam passes over the synchronization detection sensor 136 as the synchronization detection means, the value of the pixel counter in the light source driving means of the optical laser is reset to zero. Further, it is possible to pulse-drive the semiconductor laser 200A by appropriately designating the write start position, end position, dot interval, etc. starting from the synchronous detection sensors 136, 138 installed on both sides of the scanning region of the light beam, It is possible to form dots at a desired position and width in the image forming area.

  Further, when the scanning state of the light beam scanned on each of the photoconductive drums 101A to 101D is different from each other in inclination or bending, it is adjusted for each station by adjusting the attitude of the folding mirror. Color misregistration can be reduced.

  In addition, the signals of the synchronization detection sensors 136 and 138 are also used for amplitude control of the oscillating mirror 106, and the amplitude is kept constant by controlling the drive voltage and the like even when the resonance frequency and amplitude change over time. The scanning speed in the effective image area is made uniform and the image formation can be performed stably.

  In this embodiment, the imaging lenses 137 and 139 are formed on the synchronization detection sensors 136 and 138 in the main scanning direction and the sub-scanning direction by using anamorphic lenses having different curvatures in the main scanning direction and the sub-scanning direction. Yes. However, for the function of generating the horizontal synchronization detection signal, it is not always necessary to form an image in the sub-scanning direction, and a configuration in which no image is formed in the sub-scanning direction may be given with priority given to constraints such as layout.

  The image forming apparatus includes an overlay accuracy detecting unit that detects a main scanning resist and a sub-scanning resist as deviations from a reference station by reading a detection pattern of a toner image formed on the intermediate transfer belt 102. Correction control is performed.

  As shown in FIG. 3, the light beam emitted from the light source unit 200 passes through the cylindrical lens group 113, the incident mirror 111, the vibration mirror 106, and the separation mirror 112. At this time, by using the incident mirror 111, the light source unit 200 is arranged in a space between the vibrating mirror 106 and the separation mirror 112 as a separation means. By adopting this layout, the entire apparatus including the light source unit 200 is reduced in size.

However, when each optical component such as a reflection mirror and a separation mirror is incorporated in a housing of an actual machine, the image forming position of each color cannot be adjusted, and the adjustment work becomes complicated. That is, when the reflection mirror and the separation mirror are separate parts as in the configuration shown in FIG. 1, the incident angle, reflection angle, main scanning position, and sub-scanning position with the vibrating mirror are individually adjusted. There was a need to go. In addition, the vibration mirror has individual differences in the angle and shape of the deflecting surface, which is a reflection surface, and the torsion beam. Therefore, it is necessary to adjust the vibration mirror according to the individual difference of the vibration mirror.
The present invention improves these problems.

The configuration of the optical scanning device according to the present invention will be described below.
FIG. 4 is a perspective view showing the configuration of the optical scanning device according to the present invention. 4, the same components as those in the optical scanning device in FIG. 1 are denoted by the same reference numerals as those in FIG.
The optical scanning device 100 includes a light source unit (light source unit 200) including a light emitting unit (semiconductor lasers 200A to 200D) that emits a plurality of light beams, a light source driving unit (not shown) that modulates and drives the light source unit, A deflecting unit (vibrating mirror 106) having a deflecting surface for deflecting a light beam from the light source unit in a specific direction while scanning the main scanning region, and reflecting a plurality of light beams emitted from the light source unit. An incident mirror section (incident mirror section 110a) that is incident on the deflecting surface of the deflecting means, and one or several of the light beams deflected by the deflecting means are reflected in one direction and folded. The separation mirror part (separation mirror part 110b) that reflects and folds the remaining light beam in a direction opposite to the folding direction of the one or several light beams is integrated. A configuration including an incident separation mirror (incident separation mirror 110) and a scanning imaging optical system (folding mirrors 127 to 132, scanning lenses 122 to 125) for guiding a light beam from the separation mirror unit onto a surface to be scanned. is there.
Note that these components are integrally held in a single housing 100B.

  The optical scanning device 100 of the present invention is similar to the optical scanning device of FIG. 1 in that the light beam is composed of a PD as a light receiving surface that detects the light beam deflected by the oscillating mirror 106 and scanned on the image plane. It has detection means (synchronization detection sensors 136 and 138) and light source driving means for lighting the light source unit 200 in a pulsed manner in accordance with the timing when the light beam passes through the light receiving surface.

  Here, since the deflecting means is the resonant vibration mirror (vibration mirror) 106 supported by the torsion beam, low heat generation, low noise, and low power consumption can be realized as compared with a polygon mirror or the like.

  In addition, a plurality of light beams from the respective semiconductor lasers 200A to 200D are obliquely incident on the deflection surface of the vibrating mirror 106 at different incident angles in the x direction, so that the respective light beams are collectively deflected and scanned. I am doing so.

  The light beam from the light source unit 200 is folded by the incident mirror unit 110a of the incident separation mirror 110 and is incident on the deflection surface of the oscillating mirror 106, so that light for four stations is emitted by the semiconductor lasers 200A to 200D. The arrangements (intervals and emission angles) of the semiconductor lasers 200A to 200D are adjusted so that the beams are obliquely incident on the vibrating mirror 106 at different incident angles in the x direction. Specifically, the light beams emitted from the respective semiconductor lasers 200A to 200D have an angle of 2 ° with each other, and are on the surface to be scanned so as to intersect the x direction at the deflection surface of the vibrating mirror 106. Semiconductor lasers 200A to 200D are arranged on a plane orthogonal to the scanning direction.

Here, the configuration of the incident separation mirror, which is a main part of the present invention, will be described.
FIG. 5 is a schematic diagram showing the configuration of the incident separation mirror. In the drawing, the rotation axis direction of the oscillating mirror 106 is the x direction, the deflection scanning direction of the light beam by the oscillating mirror 106 is the y direction, and the direction from the separation mirror unit 110b toward the oscillating mirror 106 is the z direction.

  The incident separating mirror 110 is formed by integrally molding an incident mirror portion 110a that is an inclined reflecting surface and a separating mirror portion 110b in which two reflecting surfaces facing each other face each other at one end. The mirror 106 is disposed in the vicinity of the deflection surface side. Further, the incident separation mirror 110 is disposed below the deflection surface side of the vibration mirror 106, and the separation mirror portion 110 b is disposed immediately below the deflection surface of the vibration mirror 106. In addition, the incident mirror unit 110a is disposed on the opposite side of the light source unit 200 with the vibration mirror 106 interposed therebetween and is opposed to the light source unit 200, and further, the incident mirror unit 110a is inclined so that the reflection surface faces the vibration mirror 106 side. (See FIG. 4).

  Further, the incident separation mirror 110 has positioning means 110c for positioning the light source unit 200 and the vibrating mirror 106 so as to have a predetermined positional relationship within at least a housing that integrally supports the light source unit 200 and the vibrating mirror 106. is doing.

  For example, as shown in FIG. 5, the positioning means 110c is a protrusion protruding from two places on the lower surface of the incident separation mirror 110, and by inserting these into a recess or hole provided at a predetermined position of the housing, It is possible to position the incident separation mirror 110 in the housing. Details will be described later.

  In FIG. 5, light beams 201A, 201B, 201C, and 201D emitted from each of the plurality of semiconductor lasers 200A to 200D are incident on the incident mirror unit 110a of the incident separation mirror 110 at different oblique incident angles at desired angles and positions. Incident. The light beams 201A and 201B pass through one side of the separation mirror unit 110b and enter the incident mirror unit 110a, and the light beams 201C and 201D pass through the side of the other side of the separation mirror unit 110b and enter the incident mirror. Incident on the portion 110a.

  Note that the light beams 201A, 201B, 201, C, and 201D depend on the arrangement state and emission angle state of the semiconductor lasers 200A to 200D in FIG. 4 in the direction (sub-scanning direction, x direction) orthogonal to the main scanning direction (y direction). Have different oblique incident angles with respect to the deflection surfaces of the incident mirror part 110a and the vibrating mirror 106, and the angle and position of incidence on the incident mirror part 110a are adjusted by the collimator 104.

  Next, the light beams 201 </ b> A to 201 </ b> D are reflected by the incident mirror unit 110 a and enter the deflection surface of the vibrating mirror 106. At this time, the incident angle in the y direction with respect to the normal line of the deflection surface is adjusted to be 22.5 ° (= α / 2 + θd). Α is an incident angle of the light beams 201A to 201D emitted from the light source unit 200 and reflected by the incident mirror unit 110a to the deflection surface of the oscillating mirror 106, and θd is the oscillating mirror 106 when scanning on the photosensitive member. Are effective deflection angles of the light beams 201A to 201D.

  The light beams 201A to 201D are incident on the separation mirror unit 110b while being reflected and deflected by the vibrating mirror 106. Next, in the separation mirror unit 110b, the light beams 201A to 201D are folded back in opposite directions by the reflection surface of the separation mirror unit 110b due to the difference in the oblique incidence angle. Specifically, among the four light beams 201A to 201D, the light beams 201A and 201B are reflected in one direction (x + direction) and folded, and the remaining light beams 201C and 201D are folded in the light beams 201A and 201B. Reflected in the opposite direction (x-direction) and folded back. Thereafter, the light beam is branched toward the photoconductor corresponding to each light beam.

  By arranging the positional relationship between the oscillating mirror 106 and the incident separation mirror 110 as shown in FIG. 5, it is possible to convert the light beam whose traveling direction is the y direction into the direction of the rotation axis (x direction) of the oscillating mirror 106. Therefore, when a plurality of light emitting units are conventionally arranged in the z direction, the thickness of the optical scanning device can be reduced by arranging them in a row in the x direction.

Next, the separation of the light beam by the separation mirror unit 110b will be described.
FIG. 6 is a cross-sectional view illustrating a separation state when light beams are incident on the separation mirror unit 110b in a parallel state.
The light beams 200A and 200B and the light beams 200C and 200D deflected and scanned by the oscillating mirror 106 at parallel intervals are folded back in directions opposite to each other by the separation mirror unit 110b, but with the light beam 200A folded back to the same side. Since 200B or the light beams 200C and 200D have the same reflection angle, they enter the scanning lens or the like with the same distance between the light beams, and it is difficult to separate them into separate photoconductors.

Therefore, in the present invention, the light beam is obliquely incident on the deflection surface of the oscillating mirror 106 to improve it.
FIG. 7 is a cross-sectional view showing a light beam separation state by the separation mirror 110b in that case.
Again, the light beams 200A and 200B and the light beams 200C and 200D are folded back in directions opposite to each other by the separation mirror unit 110b. At the same time, since the light beams 200A to 200D are incident on the deflection surface of the vibrating mirror 106 at different oblique incident angles, the light beams 200A and 200B or the light beams 200C and 200D folded back to the same side are separated from each other by the separation mirror 110b. The incident angles to the reflecting surfaces are different, and as a result, the reflection angles at the separation mirror 110b are different, and the light beams 200A and 200B or the light beams 200C and 200D are separated from each other.

Next, FIG. 8 is a cross-sectional view showing a separation state when the reflection angle at the separation mirror unit 110b differs for each light beam.
The inclination angle is different between the upper part and the lower part of the two reflecting surfaces of the separation mirror part 110b. Thereby, in addition to the difference due to the oblique incidence, the light beams 200A and 200B or the light beams 200C and 200D have different reflection angles at the separation mirror portion 110b, so that the light beams 200A and 200B or the light beams 200C and 200D are different from each other. Each will be separated more greatly.

  As described above, the conditions in FIGS. 7 and 8 are adjusted in accordance with the conditions such as the photosensitive member arrangement interval corresponding to each light beam to increase or decrease the separation angle between the light beams in the separation mirror 110b. Therefore, it is easy to lay out a proper interval between the light beams on the surface of the photosensitive member.

Next, a method for adjusting the positioning of the incident separation mirror 110 by the positioning means 110c will be described.
9A and 9B show a method for adjusting the positioning of the incident separation mirror 110 in the yz plane by the positioning means 110c. FIG. 9A is a schematic perspective view and FIG. 9B is a cross-sectional view in the yz plane.
Regarding the positioning of the incident separating mirror 110, a housing 100B that integrally supports at least the light source unit 200 and the vibrating mirror 106 with the protruding positioning means 110c provided at two predetermined positions on the lower surface of the incident separating mirror 110. This is performed by fitting into two positioning holes 100h made in advance at a predetermined position with high accuracy. Thereby, the incident separation mirror 110 can be disposed at an appropriate position in a plane (yz plane) orthogonal to the rotation axis. That is, the positioning unit 110c positions the incident separation mirror 110 in a plane orthogonal to the rotation axis of the oscillating mirror 106 of the housing 100B, and sets the position of the incident mirror unit 110a with respect to the deflection surface of the oscillating mirror 106. The incident mirror section 110a allows each light beam to enter the deflection surface of the vibrating mirror 106 at an appropriate angle and distance. Further, as shown in FIG. 9B, one of the two positioning holes 100h may be made larger than the positioning means 110c so that the expansion and contraction of the housing 100B accompanying the temperature change can be absorbed.

  If there is a shape error due to individual differences on the deflection surface of the vibrating mirror 106 or the incident separation mirror 110, or if a higher accuracy than positioning by the abutment of the positioning means 110c is required, the position is confirmed during the mounting process. However, it may be fixed at an appropriate position.

10A and 10B show a method for adjusting the positioning of the incident separation mirror 110 in the z direction by the positioning means 110c. FIG. 10A is a schematic perspective view thereof, and FIG. 10B is a vibration mirror 106 and a separation mirror portion 110b. It is sectional drawing which shows the positional relationship of z direction.
The height of the positioning means 110c of the incident separation mirror 110 is set with high accuracy, the depth of the positioning hole 100h ′ provided in the housing 100B is prepared with high accuracy in advance, and the positioning means 110c is placed in the positioning hole 100h ′. By inserting, the positional relationship between the oscillating mirror 106 and the separating mirror unit 110b in the z direction, that is, the distance between the rotation axis of the deflection surface of the oscillating mirror 106 and the ridge lines of the two reflecting surface butting portions of the separating mirror unit 110b is set to a desired value. Can be.

  11A and 11B show a method for adjusting the positioning of the incident separation mirror 110 in the x direction by the positioning means 110c. FIG. 11A is a schematic perspective view thereof, and FIG. 11B is a vibration mirror 106 and a separation mirror portion 110b. It is sectional drawing which shows the positional relationship of x direction.

  When the separation mirror unit 110b moves in the x direction from the appropriate position, the height position of the reflection surface of the separation mirror unit 110b of each light beam incident on the separation mirror unit 110b is shifted in the z direction, and the separation mirror unit 110b The traveling direction of the light beam after reflection will change.

  Therefore, the deflecting surface of the vibrating mirror 106 is preliminarily provided by positioning the positioning unit 110c at a predetermined position on the lower surface of the incident separation mirror 110 with high accuracy and fitting into a positioning hole 100h '' provided at a predetermined position on the housing 100B with high accuracy. The position is adjusted so that the ridgelines that are the two reflecting surface abutting portions of the separation mirror portion 110b come to a predetermined position in a plane parallel to the rotation axis (xz plane).

  As described above, the positioning unit 110c positions the incident separation mirror 110 in a plane parallel to the rotation axis of the oscillating mirror 106 of the housing, and sets the position of the separation mirror 110b with respect to the deflection surface of the oscillating mirror 106. Is. Thereby, the incident separation mirror 110 can be disposed at an appropriate position in a plane (xz plane) parallel to the rotation axis. Specifically, the positioning means 110c vibrates so that the longitudinal direction (y direction) of the deflection surface of the vibration mirror 106 and the ridge line that is the reflection surface abutting portion of the separation mirror portion 110b are parallel and located on the same plane. The incident separation mirror 110 is positioned in the x and z directions within a plane parallel to the rotation axis of the mirror 106. Thereby, the incident position and the scanning width of the light beam at the separation mirror unit 110b can be adjusted, and the separation state can be adjusted appropriately.

Next, an optical scanning operation in the optical scanning device 100 will be described.
The light beams emitted from the respective semiconductor lasers 200 </ b> A to 200 </ b> D first pass through the collimator 104 and then enter the cylinder lens group 113 so as to be aligned in a horizontal row in the x direction, and each light beam is vibrated by the cylinder lens group 113. The light is converged in the x direction in the vicinity of the deflection surface of the mirror 106.

  Next, the incident angle in the y direction of the light beam that has passed through the cylinder lens group 113 is 22.5 ° (= α /) with respect to the normal line of the deflection surface of the oscillating mirror 106 by the incident mirror portion 110a of the incident separation mirror 110. The incident light is incident on the oscillating mirror 106 so as to cross the x direction on the oscillating mirror 106.

  Next, the light beam is incident on the separation mirror portion 110 b of the incident separation mirror 110 while being widened so that the light beams are separated from each other after being deflected by the vibrating mirror 106. In the separation mirror unit 110b, the light beams are separated in opposite directions due to the difference in the oblique incident angle.

  That is, light beams having different oblique incident angles are incident on the separation mirror unit 110b as light beams having different incident angles and incident heights, and the light beams 201A and 201B emitted from the semiconductor lasers 200A and 200B are synchronously detected by reflection. The light beams 201C and 201D emitted from the semiconductor lasers 200C and 200D are separated in the -x direction of FIG. 1 by reflection. Further, the light beams separated in the same direction are also separated.

  Of the light beams separated by the separation mirror unit 110b, the light beam 201A from the semiconductor laser 200A is reflected by the folding mirror 128, reflected again by the folding mirror 129, and spotted on the photosensitive drum 101A via the scanning lens 123. Then, a latent image based on cyan image information is formed as an image forming station.

  The light beam 201B from the semiconductor laser 200B is reflected by the folding mirror 127, forms a spot image on the photosensitive drum 101B via the scanning lens 122, and forms black image information as a second image forming station. Forming a latent image based thereon;

  The light beam 201C from the semiconductor laser 200C is reflected by the folding mirror 132, forms a spot image on the photosensitive drum 101C via the scanning lens 125, and becomes yellow image information as a fourth image forming station. Forming a latent image based thereon;

  The light beam 201D from the semiconductor laser 200D is reflected by the folding mirror 130, reflected again by the folding mirror 131, and imaged in a spot shape on the photosensitive drum 101D via the scanning lens 124, and magenta as an image forming station. A latent image based on the color image information is formed.

Next, the configuration of the image forming apparatus according to the present invention will be described.
FIG. 12 shows an example of an image forming apparatus equipped with the above-described optical scanning device 100 of the present invention.
As an image forming station, a photosensitive drum 901, a charging charger 902 for charging the surface of the photosensitive drum 901 at a high voltage around the photosensitive drum 901, and an electrostatic latent image recorded by the optical scanning device 100 are attached to the electrostatic latent image. A developing roller 903 that visualizes the toner, a toner cartridge 904 that replenishes toner to the developing roller 903, and a cleaning case 905 that scrapes and stores the toner remaining on the drum are disposed. Image recording is performed on the photosensitive drum 901 by scanning with an optical deflector.

  The above-described image forming stations are arranged in parallel in the moving direction of the intermediate transfer belt 906, and yellow, magenta, cyan, and black toner images are sequentially transferred onto the transfer belt at the same timing, and are superimposed to form a color image. Each image forming station has basically the same configuration except that the toner color is different.

  On the other hand, the recording paper is supplied from the paper supply tray 907 by the paper supply roller 908, and is sent out by the registration roller pair 909 in accordance with the recording start timing in the sub-scanning direction. The toner image is transferred from the transfer belt, and the fixing roller The image is fixed at 910 and discharged to a paper discharge tray 911 by a paper discharge roller 912.

  Although the present invention has been described with the embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and other embodiments, additions, modifications, deletions, etc. Can be changed within the range that can be conceived, and any embodiment is included in the scope of the present invention as long as the effects and advantages of the present invention are exhibited. For example, FIG. 12 shows an example of a full-color tandem type image forming apparatus having a 4-station configuration, but the optical scanning apparatus of the present invention is used as an optical writing means in a tandem-type image forming apparatus having 5 stations or more and a monochrome machine. Can be applied.

100, 100 'Optical scanning device 100B Housing 100h, 100h', 100h '' Positioning hole 102, 906 Intermediate transfer belt 101A, 101B, 101C, 101D, 901 Photosensitive drum 104 Collimator lens group 106 Vibration mirror (deflector)
DESCRIPTION OF SYMBOLS 110 Incident separation mirror 110a Incident mirror part 110b Separation mirror part 110c Positioning means 111 Incident mirror 112 Separation mirror 113 Cylindrical lens group 122-125 Scan lens 127-132 Folding mirror 136,138 Synchronization detection sensor 137,139 Imaging lens 200 Light source part 200A, 200B, 200C, 200D Semiconductor laser (light emitting part)
201A, 201B, 201C, 201D Light beam 902 Charging charger 903 Development roller 904 Toner cartridge 905 Cleaning case 907 Paper feed tray 908 Paper feed roller 909 Registration roller pair 910 Fixing roller 911 Paper discharge tray 912 Paper discharge roller

Japanese Patent No. 2924200 Japanese Patent No. 30111144 Japanese Patent No. 3445691 Japanese Patent No. 3543473 JP 2004-279947 A JP 2001-281575 A

Claims (8)

Light source means including a light emitting unit for emitting a plurality of light beams;
Light source driving means for modulating and driving the light source means;
Deflection means having a deflection surface for deflecting in a specific direction while scanning a specific area while reflecting a light beam from the light source means;
An incident mirror section that reflects a plurality of light beams emitted from the light source means and enters the deflecting surface of the deflecting means; and one or several light beams among the plurality of light beams deflected by the deflecting means An incident separation mirror integrated with a separation mirror portion that reflects and folds the remaining light beam in a direction opposite to the folding direction of the one or several light beams;
A scanning imaging optical system for guiding a light beam from the separation mirror unit onto a surface to be scanned;
With
The optical scanning device according to claim 1, wherein the plurality of light beams are reflected by the incident mirror portion at different angles and obliquely incident on a deflection surface of the deflection unit.   2. The deflecting unit according to claim 1, wherein the deflecting unit is a vibrating mirror that is supported by a torsion beam having a deflection surface serving as a rotation axis, and deflects a light beam from the light source unit to scan a specific region. Optical scanning device.   3. The optical scanning device according to claim 1, wherein the separation mirror unit includes reflection surfaces having different angles corresponding to the plurality of light beams. 4. A housing that integrally supports at least the light source means and the deflecting means;
4. The optical scanning device according to claim 1, wherein the incident separation mirror includes positioning means for positioning the light source means and the deflecting means so as to have a predetermined positional relationship within the housing. .   The positioning means positions the incident separation mirror in a plane perpendicular to the rotation axis of the deflecting means of the housing, and sets the position of the incident mirror portion with respect to the deflecting surface of the deflecting means. The optical scanning device according to claim 4.   6. The positioning means according to claim 4, wherein the positioning means positions the height of the incident separation mirror in the housing and sets a position of the separation mirror portion with respect to a deflection surface of the deflection means. Optical scanning device.   The positioning means positions the incident separation mirror in a plane parallel to the rotation axis of the deflection means of the housing, and sets the position of the separation mirror portion with respect to the deflection surface of the deflection means. The optical scanning device according to claim 4. An optical scanning device according to any one of claims 1 to 7,
An image forming apparatus comprising: a plurality of image carriers that are scanned with a light beam including image information from the optical scanning device.

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