JP3526400B2 - Multi-beam light source device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital copying machine,
The present invention relates to an optical scanning device used in a writing system of a recording device such as a laser printer or a laser facsimile, and in particular, a multi-beam in which a plurality of light beams simultaneously scan a surface to be scanned such as a photoconductor to significantly improve a recording speed. The present invention relates to a multi-beam light source device used as a light source in an optical scanning device.

[0002]

2. Description of the Related Art In an optical scanning device used in a writing system of a recording device such as a digital copying machine, a laser printer, a laser facsimile, etc., as a means for improving a recording speed, a rotary polygon mirror as a deflecting means is rotated. There is a way to increase speed. However, in this method, the durability of the motor, noise, vibration, the modulation speed of the semiconductor laser, etc. become problems, and the recording speed is limited. Therefore, a multi-beam optical scanning device has been proposed in which a plurality of light beams are scanned at a time to record a plurality of lines at the same time to improve the recording speed. As one example thereof, a method of combining light fluxes from a plurality of semiconductor laser light sources using a beam splitter, or a semiconductor in which a plurality of light emitting sources are arranged in an array as disclosed in JP-A-56-42248 There is a method using a laser array.

The above-mentioned semiconductor laser array has a plurality of light sources, but has a common sensor for detecting an output.
Although the light output cannot be fed back in real time as in a normal semiconductor laser, the light output is likely to fluctuate due to the crosstalk due to the proximity of the light source, and highly accurate light amount control cannot be performed. Also, it has the drawback of being expensive due to its peculiarity. These are disadvantageous as the number of light sources increases. On the other hand, the method of using a plurality of general-purpose semiconductor lasers and combining the light beams from the plurality of semiconductor lasers does not have the above-mentioned problems, but it is necessary to improve environmental stability and assemblability.

Therefore, the present applicant previously proposed a basic type of a new multi-beam light source device for solving these problems and emitting a plurality of beams (Japanese Patent Application No. 9-178479).
issue). As an example of the multi-beam light source device of this prior application, a plurality of semiconductor lasers, a plurality of collimator lenses which are provided in pairs with the semiconductor lasers to make respective light beams into parallel light fluxes, the plurality of semiconductor lasers and a collimator lens A first light source section having a supporting member for arranging the elements in the main scanning direction to integrally support them, a second light source section configured in the same manner as the first light source section, and the first and the first And a beam combining means for emitting the light beams of the two light source units in close proximity to each other.

[0005]

As described above, the semiconductor laser array cannot be handled in the same way as a general-purpose semiconductor laser due to restrictions on the control surface, and is not suitable for highly accurate output control. Since the collimator lens is common despite having a plurality of light sources, differences in wavelength and light emitting point position between light sources remain, the image forming position shifts, and the beams emitted from the collimator lens separate from each other. It is difficult to handle, such as diverging in the direction. On the other hand, when two or more general-purpose semiconductor lasers (LD) are used for beam combining using a beam splitter (BS) or a prism, as a typical example, as shown in FIG. And multiple prisms with multiple semiconductor lasers L
There is a method of combining the light beams from D-1 to LD-4 one by one, but the structure becomes complicated and the structure shown in FIG.
As shown in (b), each semiconductor laser is likely to be misaligned, and it is necessary to work the emission directions of the respective semiconductor lasers individually, and it is very difficult to maintain the beam spot interval because of the large misalignment over time. It has the drawback of being difficult. Further, since the amount of light becomes 1/2 each time it passes through the beam splitter surface (BS surface), the amount of light emitted from the first semiconductor laser LD-1 is BS in the second semiconductor laser LD-2. Since it passes one more surface, it is 1/2
Since the second semiconductor laser LD-3 and the fourth semiconductor laser LD-4 pass through the BS surface by two more, the emitted light amount becomes ¼, and the light amount loss increases as the number of beams increases. However, it is necessary to use a semiconductor laser that has a low light utilization efficiency and a high output.

On the other hand, in the above-mentioned multi-beam light source device of the prior application, by arranging a plurality of semiconductor lasers in the main scanning direction, it becomes possible to combine them by one beam combining means (eg, beam splitter). It is possible to realize a multi-beam light source unit that is simple, has little deviation with time, and is excellent in stability. Also, since there is no light loss and the output of the semiconductor laser is minimal, the cost is low and it can be applied to a wide range of applications depending on the exposure amount.

However, the alignment of the beam spot distances synthesized by the beam splitter in the assembling depends on the alignment accuracy of the optical axis of the light source section and the angle accuracy of the beam splitter surface and the reflecting surface of the prism in the preceding stage. Therefore, it was necessary to improve the productivity.

The present invention has been made in view of the above circumstances, and in the inventions of claims 1, 2, 3 and 6, in producing the multi-beam light source device disclosed in the prior application, the beam spot spacing is Adjustment (especially, setting of the scanning line interval (beam pitch) in the sub-scanning direction) can be easily performed by simple work, and reliable alignment can be performed to improve assembly efficiency and increase It is an object of the present invention to realize a multi-beam light source device capable of performing high quality image recording. It is another object of the inventions of claims 4 and 5 to realize a multi-beam light source device capable of maintaining a scanning line interval in the sub-scanning direction under any environment and performing stable image formation over time. To do.

Further, in the inventions of claims 7 to 11, a plurality of general-purpose semiconductor lasers are used, and the scanning line intervals of the sub-scanning on the surface to be scanned are maintained at equal intervals under any environment, and the time elapses. It is an object of the present invention to realize a multi-beam light source device capable of performing stable image formation and performing high-quality image recording.

[0010]

In order to achieve the above object, the invention according to claim 1 contemplates that a light beam from a light source is focused on a surface to be scanned by a scanning optical means to form a beam spot and main scanning is performed. A multi-beam light source device for emitting a plurality of light beams, which is used as the above-mentioned light source in an optical scanning device for scanning in a direction, wherein an even number of semiconductor lasers and a pair of the semiconductor lasers are provided to parallelize the light beams from the semiconductor lasers. A first light source section having an even number of collimator lenses for converting light flux, a support member for arranging the even number of semiconductor lasers and the collimator lenses symmetrically with respect to the emission axis in the main scanning direction and integrally supporting these; A multi-beam composed of a second light source part configured similarly to the first light source part, and a beam combining means for emitting the light beams of the first and second light source parts close to each other in the sub-scanning direction. In the source device, it is characterized in that it has deployed as spaced a predetermined angle in the main scanning direction and the injection shaft is injection shaft and the second light source section of the first light source.

The invention according to claim 2 is used as the light source in an optical scanning device for converging a light beam from a light source on a surface to be scanned by a scanning optical means to form a beam spot and scanning in the main scanning direction. A multi-beam light source device for emitting a plurality of light beams, comprising an odd number of semiconductor lasers, an odd number of collimator lenses that form a parallel light beam from the semiconductor lasers, and the odd number of semiconductor lasers. A first light source unit having a semiconductor laser and a collimator lens arranged in the main scanning direction, a semiconductor laser located at the center of the semiconductor laser arranged on an emission axis, and a supporting member integrally supporting these, and an even number of light sources. A semiconductor laser and an even number of collimator lenses which are provided in pairs with the semiconductor laser and convert a light beam from the semiconductor laser into a parallel light beam, and the even number of semiconductor lasers and collimator. A second light source section having a lens and a support member that is arranged symmetrically with respect to the emission axis in the main scanning direction and integrally supports these, and the light beams of the first and second light source sections in the sub scanning direction. In a multi-beam light source device including a beam synthesizing means for emitting light in close proximity to each other, the multi-beam light source device is arranged such that the emission axis of the first light source section and the emission axis of the second light source section are separated by a predetermined angle in the main scanning direction. It is characterized by.

The invention according to claim 3 is the invention according to claim 1 or 2.
In the multi-beam light source device described in (1), a holding member that holds the first and second light source units and the beam synthesizing means in a substantially integrated module is provided. A plurality of light beams are converged on the surface to be scanned to form a beam spot and scanned in the main scanning direction.) The optical axis (rotational reference) C of the scanning optical means is rotated with respect to the scanning optical means. It is supported so that it is arranged such that the emission axis of the first light source section and the emission axis of the second light source section are symmetrical with respect to the optical axis C in the main scanning direction. To do.

According to a fourth aspect of the present invention, in the multi-beam light source device according to the third aspect, the materials of the supporting members of the first and second light source parts and the holding member to which the supporting members are fixed are The material of the base member is the same.

According to a fifth aspect of the present invention, in the multi-beam light source device according to the third aspect, the emission axis intervals of the first and second light source portions on the surface to be scanned are set to the beam spots from the respective light source portions. It is characterized in that it is set to be ¼ or less of the adjacent intervals.

According to a sixth aspect of the present invention, in the multi-beam light source device according to the third aspect, there is provided a positioning means for rotating the holding member about the optical axis (rotation reference) C as a center of rotation. The first and second light source units are provided with a positioning unit that is rotatable with respect to the holding member about the injection shaft.

The invention according to claim 7 is used as the light source in an optical scanning device for converging a light beam from a light source on a surface to be scanned by a scanning optical means to form a beam spot and scanning in the main scanning direction. A multi-beam light source device for emitting a plurality of light beams, comprising an even number of semiconductor lasers, an even number of collimating lenses which are provided in pairs with the semiconductor lasers, and convert the light beams from the semiconductor lasers into parallel light beams, A first light source unit having a semiconductor laser and a collimator lens symmetrically arranged in the main scanning direction with respect to an emission axis and integrally supporting these members, and a second light source unit configured similarly to the first light source unit. And a beam combining means for emitting the light beams of the first and second light source parts in close proximity to each other in the sub-scanning direction, the first and second light source parts. The pair of semiconductor laser and a collimator lens in the symmetrical positions with respect to the exit axis, the shift amount from the collimating lens optical axis of the semiconductor laser is characterized in that it is the same amount.

The invention according to claim 8 is used as the light source in an optical scanning device for converging a light beam from a light source on a surface to be scanned by a scanning optical means to form a beam spot and scanning in the main scanning direction. A multi-beam light source device for emitting a plurality of light beams, comprising an odd number of semiconductor lasers, an odd number of collimator lenses that form a parallel light beam from the semiconductor lasers, and the odd number of semiconductor lasers. A first light source unit having a semiconductor laser and a collimator lens arranged in the main scanning direction, a semiconductor laser located at the center of the semiconductor laser arranged on an emission axis, and a supporting member integrally supporting these, and an even number of light sources. A semiconductor laser and an even number of collimator lenses which are provided in pairs with the semiconductor laser and convert a light beam from the semiconductor laser into a parallel light beam, and the even number of semiconductor lasers and collimator. A second light source section having a lens and a support member that is arranged symmetrically with respect to the emission axis in the main scanning direction and integrally supports these, and the light beams of the first and second light source sections in the sub scanning direction. A multi-beam light source device comprising beam combining means for emitting light in close proximity to each other,
With respect to the pair of the semiconductor laser and the collimator lens that are symmetrical with respect to the emission axis of the light source section, the amount of shift from the optical axis of the collimator lens of the semiconductor laser is the same.

The invention according to claim 9 is the invention according to claim 7 or 8.
In the multi-beam light source device according to the item (1), a shift of the semiconductor laser from the optical axis of the collimating lens is such that the principal rays emitted from the plurality of semiconductor lasers supported by the first light source unit are in the vicinity of the rotating polygon mirror of the optical scanning device. In the main scanning direction, the chief rays emitted from the plurality of semiconductor lasers supported by the second light source section intersect with the emission axis of the first light source section in the main scanning direction, and the main rays are emitted in the vicinity of the rotary polygon mirror of the optical scanning device. It is characterized in that it is set so as to intersect the emission axis of the light source section in the main scanning direction.

According to a tenth aspect of the present invention, in the multi-beam light source device according to the seventh, eighth or ninth aspect, the emission axis of the first light source section and the emission axis of the second light source section are in the main scanning direction. It is characterized by being deployed so as to be separated from each other.

The invention of claim 11 relates to claims 7, 8 and
In the multi-beam light source device according to 9 or 10,
A holding member for holding the first and second light source units and the beam synthesizing means in a substantially integrated module is provided, and the holding member is provided (a plurality of light beams from the multi-beam light source device are placed on the surface to be scanned). The light is condensed to form a beam spot and scanned in the main scanning direction. The scanning optical means is rotatably supported about the optical axis (rotational reference) C of the scanning optical means, The first light source unit and the second light source unit are independently rotatable with respect to the holding member with each emission axis as a rotation center.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the illustrated embodiments.

(Embodiment 1) First, embodiments of claims 1 to 6 will be described. FIG. 1 is a diagram showing an embodiment of the present invention, and is a perspective view showing a schematic configuration of a multi-beam light source device in an exploded state, and is a configuration of a 4-beam light source unit using a total of four general-purpose semiconductor lasers. An example is shown. Further, FIG. 2 is a view showing a state of a cross section of the first light source section of the 4-beam light source unit and the arrangement positions of the four semiconductor lasers together, and FIG. 3 is an optical scanning device equipped with the 4-beam light source unit. It is a figure which shows the outline | summary of an apparatus.

In FIG. 1, semiconductor lasers 101 and 10 are provided.
2 are press-fitted into and supported by fitting holes (not shown) formed in parallel on the back side of the aluminum die-cast support member 103 at intervals of 8 mm in the main scanning direction. Further, the collimator lenses 104 and 105 are provided for the respective semiconductor lasers 101 and
The divergent light flux of 102 is aligned in the X direction so that it becomes a parallel light flux, and Y, so that it is in a predetermined beam emission direction.
U-shaped support parts 103-1 and 10 formed in pairs with the fitting holes of the semiconductor lasers 101 and 102 by aligning the positions in the Z direction.
An adhesive (for example, an ultraviolet (UV) curing adhesive) is filled and fixed in the gap 3-2 to form the first light source unit LD1. Further, the second light source unit LD2 also includes the semiconductor laser 111,
112, collimating lenses 114 and 115, support member 1
13 and has the same configuration as the first light source unit LD1.

Here, FIG. 2A shows the first light source unit LD.
1, second light source unit LD2, and beam combining prism 20
2 is incorporated into a holding member composed of a base member 201 and a holder 203 to form a substantially integrated module, and X, Y of a first light source unit LD1 portion of a multi-beam light source unit.
2B shows a state of a cross section parallel to the direction, and FIG. 2B shows an arrangement position when the semiconductor lasers of the first and second light source sections are viewed from the back side in the X direction. As shown in FIG. 2, the semiconductor lasers 101 and 102 of the first light source unit LD1 and the collimator lenses 104 and 105 are the emission axis a1 of the first light source unit LD1 (the middle point O of the two semiconductor lasers 101 and 102). The axis extending in the beam emission direction from is called as the emission axis) is arranged symmetrically, and the distance d between the collimator lenses 104 and 105 is set smaller than the distance D between the semiconductor lasers 101 and 102 (that is, the collimator lens 104, The optical axis of 105 is arranged so as to be eccentric to the emission axis a1 side in the Y direction).
As a result, the laser beams from the semiconductor lasers 101 and 102 are emitted by the collimator lenses 104 and 105 at predetermined angles in the intersecting directions. The second light source unit LD2 is similarly configured, and the semiconductor lasers 111 and 112 and the collimator lenses 114 and 115 have the emission axis a2 of the second light source unit LD2 (only the emission axis a2 is a broken line in FIG. 2A). Are arranged symmetrically with respect to each other, and the distance between the collimator lenses 114 and 115 is set smaller than the distance between the semiconductor lasers 111 and 112. The laser beams from the respective semiconductor lasers 111 and 112 are collimated lenses. Injection axis a2 by 114 and 115
It is injected with a predetermined angle in a direction intersecting with each other symmetrically. The beam emission direction is set so that the intersection position of any of the light source units is near the polygon mirror (rotating polygon mirror) reflecting surface of the optical scanning device shown in FIG.

The first light source unit LD1 and the second light source unit L
D2 is the fitting holes 201-1 and 201 of the base member 201.
-2 to the cylindrical portions 103 of the supporting members 103 and 113, respectively.
-3 and 113-3 are fitted together and fixed to the back side of the base member 201 with a screw penetrating from the front surface of the base member 201. Then, after the beam synthesizing prism 202 is bonded and fixed to the front surface of the base member 201, the beam synthesizing prism 2
02 is fitted into the concave portion of the holder 203 and the base member 2
01 and the holder 203 are fixed. It should be noted that the expansion rates of the support members 103 and 113 and the base member 2 due to changes in the environmental temperature.
If there is a difference with the expansion coefficient of 01, the larger expansion coefficient is distorted (flexed), the emission direction (angle) of the light beam is changed, and the fluctuation of the beam pitch described later is amplified. The materials of the support members 103 and 113 of the first and second light source parts and the material of the base member 201 are the same.

The beam synthesizing prism 202 has a polarization beam splitter surface 202-3 inside and a second light source unit LD.
The half-wave plate (λ / 2
A plate) 202-1 is provided, and a reflecting surface 202-2 that reflects the light beam from the second light source unit LD2 is provided. The light beam from the first light source unit LD1 is transmitted through the polarization beam splitter surface 202-3 as it is and emitted, and the light beam from the second light source unit LD2 is ½. The polarization direction is rotated by 90 degrees by the wave plate 112, reflected upward by the inclined surface 202-2, and further reflected by the polarization beam splitter surface 202-3 and emitted. This makes it possible to reduce the light amount loss and easily combine the light beams from the first and second light source units.

As shown in FIG. 2, the first light source unit LD1 and the second light source unit LD1
The light source unit LD2 of the first light source unit LD2 is arranged on the base member 201 at an interval of R in the sub-scanning direction, but as described above, the light beam from the second light source unit LD2 is generated by the beam combining prism 202. The light beam from the light source unit LD1 is combined with the light beam, and the light beams are emitted close to each other in the sub-scanning direction. At this time, the light source units are arranged such that the emission axes a1 and a2 do not coincide with each other in the main scanning direction and are separated by a predetermined distance m (for example, 1 mm). Two
No. 03 rotation reference C (the optical axis of the scanning optical system shown in FIG. 3 serves as a rotation reference) and has a predetermined angle β in each intersecting direction (that is, , The emission axis a1 of the first light source unit LD1 and the second light source unit L
It is arranged so that the ejection axis a2 of D2 is separated by a predetermined angle β in the main scanning direction) and is also separated by a predetermined distance on the surface to be scanned. In the scanning optical system (FIG. 3) of the embodiment described later, the distance M between the emission axes a1 and a2 on the surface to be scanned is set to, for example, about 1 mm (however, the magnification is determined by the scanning optical system. different).

The adjustment of the pitch in the sub-scanning direction on the surface to be scanned is performed by the base member 201 for each of the light source sections LD1 and LD2.
When the base member 201 is fixed to the fitting hole 201-
1, 021-2 as a reference (that is, the emission axes a1 and a2 as shown in FIG. 2B, respectively), the inclination θ1 between the semiconductor lasers 101 and 102 of the first light source unit LD1 and the second Semiconductor laser 11 of the light source unit LD2 of
This is done by adjusting the mutual inclination θ2 of 1, 112, respectively, but as shown in FIG. 5A, the arrival points of the injection axes a1, a2 on the surface to be scanned O, O '(first Light source part LD1
Beam spots LD1-L and LD1-R in
The center point is O, and the two beam spots LD2-L and LD2-R in the second light source unit LD2 are O ') because a slight deviation occurs in the sub-scanning direction due to the precision of parts such as the beam combining prism. The positions of the beam spots from the respective light sources do not coincide with each other and are shifted by ΔZ in the sub-scanning direction. Therefore, by rotating the holding member (the holder 203 and the base member 201) around the rotation reference C (optical axis of the scanning optical system) shown in FIGS. 2 and 5A in the α direction, FIG. As shown in FIG. 3, after the exit axis arrival points O and O ′ on the surface to be scanned are aligned in the sub-scanning (horizontal) direction,
The first light source unit LD1 with O ′ as the center of rotation
Then, θ1 and θ2 of the second light source unit LD2 are adjusted to adjust the sub-scanning pitch, and each light source unit is fixed to the base member 201.

The base member 201 is held by a holder 203 in an optical housing (not shown) in which the scanning optical system shown in FIG. 3 is housed. The holder 203 is provided with the cylindrical portion 203-1 that serves as the rotation reference C, and the rotation reference C of the cylindrical portion 203-1 and the optical axis of the scanning optical system are aligned so that the cylindrical portion 203-1 is not shown. The light source unit 301 is positioned by engaging with the hole of the optical housing for positioning.
However, the actual scanning line and the horizontal line of the light source unit 301 do not coincide with each other because there is a parallelism error of, for example, a toroidal lens in each scanning optical system, and the beam spot LD2-R in FIG. The pitch P1 of LD1-R and the pitch P3 of LD1-L and LD2-L can be obtained, but the pitch P2 of LD1-R and LD1-L cannot be obtained. At this time, Δθ (= θ2−θ1) maintains a predetermined value, so in the embodiment, the holder 203 is rotatably provided in the cylindrical portion 203-1 with respect to the optical housing, and the lever 203-2 is provided on the side surface of the holder 203. By providing the lever 203-2 up and down by a motor or the like, the holder 203 is rotated around the rotation reference C while being attached to the optical housing to adjust the tilt and correct P2. .

However, if the distance M between the emission axis arrival points O and O'between the light source portions is larger than the beam spot distance L of the first light source portion LD1, the pitch P2 of the beam spot in the sub-scanning direction is corrected. As a result, P1 and P3 also change, so it is necessary to contain this change to the extent that the image quality is not affected. Generally, it is considered that the pitch change in the sub-scanning direction can be allowed if it is about ¼ of the pitch P. Therefore, the distance M between the exit axis reaching points O and O ′ on the surface to be scanned is M.
Is preferably set to 1/4 or less of the distance L between the beam spots from each light source unit. In the present embodiment, the beam spot distance L of each light source unit is 8 mm, the distance M between the exit axis arrival points O and O ′ on the surface to be scanned is 1 mm, and the pitch change in the sub-scanning direction is 1/8. I am trying.

Next, an embodiment of the multi-beam optical scanning device will be described with reference to FIG. In FIG. 3, four light beams emitted from a light source unit 301 held in an optical housing (not shown) intersect through a cylinder lens 302 in the vicinity of a reflection position of a polygon mirror 303 serving as a deflecting means, and then the polygon mirror 303. After being deflected and scanned by, the light is passed through the fθ lens 304 having a two-sheet structure, reflected by the folding mirror 307 toward the photoconductor 309, and scanned by the toroidal lens 308.
An image is recorded on the image by scanning four lines adjacent to each other at a predetermined pitch P in the sub-scanning direction at the same time in the main scanning direction S with the four beam spots formed on the image. A mirror 305 for synchronization detection is arranged outside the image area of the folding mirror 307.
The light beam reflected by 5 is the synchronization detection sensor 306.
Detected by. The synchronization detection sensor 306 is composed of two sensor units, that is, a first sensor unit 306-1 arranged perpendicularly to the main scanning direction S and a second sensor unit 306-2 inclined at about 45 degrees. In the first sensor unit 306-1, the light beams that sequentially arrive are separated in time series, and a synchronization detection signal for each light beam is generated.
The sensor unit 306-2 detects the beam pitch in the sub-scanning direction for any two light beams from the difference between the time intervals from the first sensor unit 306-1. And
The pitch calculation unit 311 calculates a pitch correction amount from the beam pitch detected by the synchronization detection sensor 306 and sends it to the motor control unit 312, and the motor control unit 312 controls the lever 203-2 of the holder 203 based on the pitch correction amount. The combined pulse motor 310 is controlled to control the pulse motor 31.
0 to move the lever 203-2 in the Z direction and the holder 20
By rotating 3 around the rotation reference C to adjust the inclination, the above-mentioned deviations due to the beam spot interval at the time of mounting and environmental changes are automatically corrected, and a predetermined pitch is always maintained. I have to. In this example,
When the beam spots from the respective light source units are arranged as shown in FIG. 5, the two beams LD2 from the second light source unit LD2 are emitted.
-R, LD2-L is detected by the synchronization detection sensor 306,
The correction is performed so that the pitch in the sub-scanning direction becomes 3P. This is because the larger the measurement pitch, the smaller the error.

The embodiment of the four-beam light source unit using four semiconductor lasers and the optical scanning device equipped with the light source unit has been described above. Next, another embodiment of the present invention is shown in FIG. The 3-beam light source unit will be described. As is apparent from comparison with FIG. 1, the 3-beam light source unit shown in FIG. 4 is different from the 4-beam light source unit only in the configuration of the first light source unit LD1, and the other configurations are the same. First light source unit LD shown in FIG.
1, the semiconductor laser 121 and the collimator lens 12
2 is one set, and the semiconductor laser 121 and the collimator lens 122 are arranged on the emission axis corresponding to the above-mentioned a1 and are similarly supported by the support member 123. That is, in FIG. 2, it corresponds to a configuration in which one set of the semiconductor laser 121 and the collimator lens 122 is arranged on the emission axis a1 of the first light source unit LD1.

FIG. 6 is a diagram showing the arrangement of the beam spots on the surface to be scanned. The arrival point O of the emission axis of the first light source section LD1 and the emission axis of the second light source section LD2 on the surface to be scanned. As in the case of four beams, the arrival points O ′ are arranged so as not to coincide with each other in the main scanning direction and apart from each other by a distance M (for example, 1 mm), and symmetrically with respect to the rotation reference C (optical axis of the scanning optical system). Predetermined angle in the crossing direction (corresponding to β in Fig. 2)
Therefore, the beam spot from the first light source unit LD1 is positioned on the emission axis, that is, at the emission axis arrival point O separated by 0.5 mm from the rotation reference C.

The beam pitch P in the sub-scanning direction is adjusted by rotating the holder 203 about the rotation reference C so that the emission axis reaching point O'of the second light source unit LD2 is moved to the first light source unit in the sub-scanning direction. After aligning with the exit axis arrival point O of LD1, the inclination of the support member 113 (that is, the two beam spots LD2-R and LD2 is set so that the distance between the beam spots LD2-R and LD2-L in the sub-scanning direction is 2P). −
It suffices to fix the first light source unit LD1 to the base member 201 by adjusting the inclination (θ between L) θ, and no adjustment is necessary when fixing the first light source unit LD1.

Of course, the three-beam light source unit may have the same structure as the four-beam light source unit shown in FIGS. 1 and 2, but the semiconductor laser and the collimating lens on one side may be removed from one of the light source sections. In this case, since the semiconductor laser and the collimator lens of the light source unit having the one-beam configuration are not on the emission axis, adjustment is required when fixing any light source unit to the base member as in the four-beam light source unit.

It is also possible to increase the number of semiconductor lasers and collimator lenses for each light source section and arrange and hold three or more semiconductor lasers and collimator lenses. Similar to the first light source unit in the beam light source unit, an odd number of semiconductor lasers and collimator lenses are arranged in the main scanning direction, and the semiconductor lasers and collimator lenses located at the center are arranged on the emission axis to support them. It may be integrally supported by a member, or if it is an even number, similarly to the second light source unit, an even number of semiconductor lasers and collimator lenses are arranged symmetrically with respect to the emission axis in the main scanning direction to support them. The members may be integrally supported. In addition, when arraying and holding three or more semiconductor lasers and collimating lenses for each light source unit,
Positioning means that is arranged such that the emission axis of the first light source section and the emission axis of the second light source section are separated by a predetermined angle in the main scanning direction, and that is rotatable about the rotation reference C as a rotation center.
The pitch adjustment in the sub-scanning direction is also performed in the same manner as in the above-described embodiment, in which the first and second light source units are provided with a positioning unit that is rotatable with respect to the base member about the emission axis as a rotation center. be able to.

(Embodiment 2) Next, embodiments of claims 7 to 11 will be described. The basic configuration of the multi-beam light source device according to this embodiment is a 4-beam light source unit using a total of four general-purpose semiconductor lasers as shown in FIG. 1, or a general-purpose semiconductor laser as shown in FIG. It has the same configuration as the three-beam light source unit using three. The configuration of the optical scanning device according to this embodiment is also the same as that of the optical scanning device shown in FIG.

First, the four-beam light source unit shown in FIG. 1 will be described as an example. As already described in Example 1,
In the 4-beam light source unit having the configuration shown in FIG. 1, the semiconductor lasers 101 and 102 are formed on the back side of the aluminum die-cast support member 103 in parallel with each other at intervals of 8 mm in the main scanning direction (not shown). Are press-fitted into and supported by. Further, the collimator lenses 104 and 105 are aligned in the X direction so that the divergent light beams of the respective semiconductor lasers 101 and 102 are parallel light beams, and are also aligned in the Y and Z directions so as to have a predetermined beam emission direction. Then, an adhesive (for example, ultraviolet (UV) curing adhesive) is filled and fixed in the gap between the U-shaped support portions 103-1 and 103-2 formed in a pair with the fitting holes of the semiconductor lasers 101 and 102. 1 light source unit LD1. In addition, the second light source unit LD2 also includes the semiconductor lasers 111 and 112 and the collimator lens 11.
4, 115 and the support member 113, and the first light source unit L
It has the same configuration as D1.

Here, FIG. 7A shows the first light source unit LD.
1, second light source unit LD2, and beam combining prism 20
2 is incorporated into a holding member composed of a base member 201 and a holder 203 to form a substantially integrated module, and X, Y of a first light source unit LD1 portion of a multi-beam light source unit.
7B shows a state of a cross section parallel to the direction, and FIG. 7B shows an arrangement position when the semiconductor lasers of the first and second light source sections are viewed from the back side in the X direction. As shown in FIG. 7, the semiconductor lasers 101 and 102 of the first light source unit LD1 and the collimator lenses 104 and 105 are the emission axis a1 of the first light source unit LD1 (the middle point O of the two semiconductor lasers 101 and 102). The axis extending in the beam emission direction from is called the emission axis). Further, the second light source unit LD2 is similarly configured, and the semiconductor lasers 111 and 112 and the collimator lenses 114 and 115 are the same as the second light source unit LD2.
Are arranged symmetrically with respect to the injection axis a2.

The first light source unit LD1 and the second light source unit L
D2 is the fitting holes 201-1 and 201 of the base member 201.
-2 to the cylindrical portions 103 of the supporting members 103 and 113, respectively.
-3 and 113-3 are fitted together and fixed to the back side of the base member 201 with a screw penetrating from the front surface of the base member 201. Then, after the beam synthesizing prism 202 is bonded and fixed to the front surface of the base member 201, the beam synthesizing prism 2
02 is fitted into the concave portion of the holder 203 and the base member 2
01 and the holder 203 are fixed. It should be noted that the expansion rates of the support members 103 and 113 and the base member 2 due to changes in the environmental temperature.
If there is a difference with the expansion coefficient of 01, the larger expansion coefficient is distorted (flexed), the emission direction (angle) of the light beam is changed, and the fluctuation of the beam pitch described later is amplified. The materials of the support members 103 and 113 of the first and second light source parts and the material of the base member 201 are the same.

The beam synthesizing prism 202 has a polarization beam splitter surface 202-3 inside and a second light source unit LD.
The half-wave plate (λ / 2
A plate) 202-1 is provided, and a reflecting surface 202-2 that reflects the light beam from the second light source unit LD2 is provided. The light beam from the first light source unit LD1 is transmitted through the polarization beam splitter surface 202-3 as it is and emitted, and the light beam from the second light source unit LD2 is ½. The polarization direction is rotated by 90 degrees by the wave plate 112, reflected upward by the inclined surface 202-2, and further reflected by the polarization beam splitter surface 202-3 and emitted. This makes it possible to reduce the light amount loss and easily combine the light beams from the first and second light source units.

As shown in FIG. 7, the first light source unit LD1 and the second light source unit LD1
The light source unit LD2 of the first light source unit LD2 is arranged on the base member 201 at an interval of R in the sub-scanning direction, but as described above, the light beam from the second light source unit LD2 is generated by the beam combining prism 202. The light beam from the light source unit LD1 is combined with the light beam, and the light beams are emitted close to each other in the sub-scanning direction. At this time, the light source units are arranged so that the emission axes a1 and a2 do not coincide with each other in the main scanning direction and are separated by a predetermined distance m (for example, 1 mm).

When the multi-beam light source device having the above structure is mounted on the optical scanning device having the structure shown in FIG. 3, the pitch in the sub-scanning direction on the surface to be scanned is adjusted by each light source unit LD1, L.
When fixing the support members 103 and 113 to the base member 201 for each D2, the fitting holes 201-1 of the base member 201,
The support members 103 and 113 are rotated with 201-2 as a reference (that is, with reference to the emission axes a1 and a2 as shown in FIG. 7B), and the semiconductor lasers 101 and 102 of the first light source unit LD1 are mutually rotated. Of the semiconductor lasers 111 and 112 of the second light source unit LD2 and the inclination θ2 of the semiconductor lasers 111 and 112 are adjusted.

By the way, as shown in FIG. 7, the semiconductor lasers 101 and 102 and the collimating lenses 104 and 105 of the first light source unit LD1 are connected to the emission axis a1 of the first light source unit LD1.
Are arranged symmetrically with respect to the semiconductor lasers 101 and 102.
The distance d between the collimator lenses 104 and 105 is set to be smaller than the distance D (in other words, the semiconductor laser is arranged in the main scanning direction with respect to the optical axis of the collimator lens). As a result, each semiconductor laser 101,
The light beam from 102 collimates lenses 104, 1
Injected by 05 at a predetermined angle in the respective intersecting directions. The second light source unit LD2 is similarly configured, and the semiconductor lasers 111 and 112 and the collimator lens 1 are arranged.
14 and 115 are arranged symmetrically with respect to the emission axis a2 of the second light source unit LD2, and the distance between the collimator lenses 114 and 115 is set smaller than the distance between the semiconductor lasers 111 and 112. The light beams from 111 and 112 are emitted by the collimator lenses 114 and 115 at a predetermined angle in directions that intersect symmetrically with the emission axis a2. The beam emitting direction is set so that the intersection position of any of the light source units is near the reflecting surface of the polygon mirror (rotating polygon mirror) of the optical scanning device shown in FIG.

That is, the amount of shift of each semiconductor laser from the optical axis of the collimator lens paired with it (as shown in FIG. 7, the respective semiconductor lasers 101, 102,
The shift amounts of 111, 112 are δ ₁₀₁ , δ ₁₀₂ , δ ₁₁₁ , δ
_112, and the sub-scanning direction component of the shift amount is ε ₁₀₁ , ε
₁₀₂ , ε ₁₁₁ , ε ₁₁₂ ) are individually adjusted,
It is possible to cause the light beams emitted from all the semiconductor lasers to intersect in the main scanning direction in the vicinity of the reflecting surface of the polygon mirror. Also, by adjusting in this way,
It is also possible to make the center points O and O ′ of the beam spots of the light beams from the light source units LD1 and LD2 coincide with the optical axis C on the surface to be scanned. However, with such an adjustment, the shift amount from the optical axis of the collimator lens of the semiconductor lasers supported at symmetrical positions with respect to the emission axes a1 and a2 of the two light source sections LD1 and LD2 is different.

More specifically, referring to FIG. 10, by shifting the semiconductor lasers 101, 102, 111, 112 from the optical axes of the collimating lenses 104, 105, 114, 115, near the polygon mirror reflecting surface. The shift amount can be set so as to intersect the optical axis C in the main scanning direction. At this time, the shift amount δ of the semiconductor laser 101 supported by the first light source unit LD1.
And _101, a shift amount [delta] ₁₀₂ of the semiconductor laser 102 supported at symmetrical positions about the injection shaft a1 and the semiconductor laser 101, the exit axis a1 and the optical axis C is 0.5m in the main scanning direction
Since there is a shift of m, δ ₁₀₁ : δ ₁₀₂ = (4 + 0.5) :( 4-0.5) = 1.
There is a difference in shift amount such as 3: 1. This phenomenon is the same for the semiconductor lasers 111 and 112 (these are symmetrical with respect to the emission axis a2) for the second light source unit LD2 (shift ratio is δ ₁₁₁ : δ ₁₁₂ = 1: 1.3). is there).

After adjusting the above shift amount, in order to obtain a desired pitch on the surface to be scanned, the two light source units LD1 and LD1 are connected.
By rotating the second support members 103 and 113 with the fitting holes 201-1 and 201-2 of the base member 201 as a reference, as shown in FIG.
Put out 2 and pitch P1 + P2 with LD2-R and LD2-L
Issue + P3. But the problem here is P1 and P
3 is not a desired pitch, but is asymmetric. This is because the shift amount of each semiconductor laser on the light source side is different, and thus the sub-scanning direction component of the shift amount generated by the rotation of each light source unit LD1, LD2 is different (that is,
In FIG. 7, ε ₁₀₁ ≠ ε ₁₀₂ and ε ₁₁₁ ≠ ε ₁₁₂ ), P2 and P1
Although the pitch of + P2 + P3 has been obtained, LD
Center O of 1-R and LD1-L, and LD2-R and LD2
This is because the center O ′ of −L is displaced in the sub-scanning direction as shown in FIG. If this displacement amount is set to 0 in the main / sub scanning direction as shown in FIG. 8B and O and O ′ coincide with the optical axis C, then P1 = P2 = P3, but only with the rotation adjustment on the light source side. , The amount of deviation cannot be zero.

The asymmetry of the pitch on the surface to be scanned means that the shift amount on the light source side is δ ₁₀₁ ≠ δ ₁₀₂ and δ ₁₁₁ ≠.
It is caused by the difference such as δ ₁₁₂ . Therefore, this problem can be solved by setting δ ₁₀₁ = δ ₁₀₂ and δ ₁₁₁ = δ ₁₁₂ . When the shift amount is set in this way, it becomes impossible to intersect all the light beams in the main scanning direction in the vicinity of the reflecting surface of the polygon mirror, but at least the semiconductor lasers 101 and 102 supported by the first light source unit LD1 are collimated. Lens 104,10
For the pair of 5, while maintaining the relationship of δ ₁₀₁ = δ _102, a
1 and the pair of the semiconductor lasers 111 and 112 and the collimating lenses 114 and 115 supported by the second light source unit LD2 can be crossed with a2 while maintaining the relationship of δ ₁₁₁ = δ _112. it can. By doing so, the problem of asymmetry of the sub-scanning beam pitch can be improved while minimizing the variation in the main scanning direction of the light beam incident on the reflecting surface of the polygon mirror.
The inner diameter of the polygon mirror can be reduced.

In the above description, the semiconductor lasers are first shifted in the main scanning direction, and the pitches P1, P2 and P3 are obtained on the surface to be scanned by rotating the light source sections LD1 and LD2. For example, the first and second light source units LD1 and LD2
For some reason, the rotation amounts θ1 and θ2 of the support members 103 and 113 are to be kept small for some reason, or are not rotated. For this reason, they are first shifted not only in the main scanning direction but also in the sub-scanning direction and then on the surface to be scanned. The same applies when obtaining the pitch. Further, this adjustment method is performed by the first light source unit L
This is effective in the case of a multi-beam light source device in which both D1 and the second light source unit LD2 have an even number of two or more semiconductor lasers and collimating lenses arranged and held.

That is, as shown in FIG. 11, the shift amounts of the semiconductor lasers supported by the first light source section and arranged symmetrically with respect to the emission axis a1 are δ ₁₁ = δ ₁₂ , δ ₁₃ = δ ₁₄ , δ.
₁₅ = δ ₁₆ , ..., Is supported by the second light source unit and has an emission axis a.
If the shift amounts of the semiconductor lasers arranged symmetrically with respect to 1 are set as δ ₂₁ = δ ₂₂ , δ ₂₃ = δ ₂₄ , δ ₂₅ = δ ₂₆ , ... Is emitted from the semiconductor laser supported by the second light source section so that the light beam emitted from the semiconductor laser supported by the first light source section near the reflection surface of the polygon mirror intersects the emission axis a1. The light beam can be made to intersect the emission axis a2, and in the sub-scanning direction, it becomes possible to obtain scanning lines at equal intervals at a desired pitch on the surface to be scanned.

This is because, regarding the first light source section,
The respective semiconductor lasers and the collimator lens are arranged symmetrically with respect to the emission axis a1, and the second light source section is arranged so that the respective semiconductor lasers and the collimator lens are arranged symmetrically with respect to the emission axis a2. If the Y direction component (main scanning direction component) of the shift amount from the optical axis of the collimator lens of the semiconductor laser at the appropriate position is the same amount (that is, ζ ₁₁ = ζ ₁₂ , ζ ₁₃ = ζ ₁₄ , ζ ₁₅ = ζ ₁₆ , ...
..., ζ ₂₁ = ζ ₂₂ , ζ ₂₃ = ζ ₂₄ , ζ ₂₅ = ζ ₂₆ , ...
.), Near the reflecting surface of the polygon mirror, the light beams of the respective semiconductor lasers supported by the first light source unit are emitted from the emission axis a1, and the light beams of the respective semiconductor lasers supported by the second light source unit are emitted from the emission axis a2. Intersect with.

At this time, δ ₁₁ = δ ₁₂ , δ ₁₃ = δ ₁₄ , δ ₁₅ of the shift amount from the optical axis of the collimator lens of the semiconductor laser.
= Δ ₁₆ , ..., δ ₂₁ = δ ₂₂ , δ ₂₃ = δ ₂₄ , δ ₂₅ =
δ ₂₆ , ... And ζ ₁₁ = ζ of the main scanning direction component of the shift amount
₁₂ , ζ ₁₃ = ζ ₁₄ , ζ ₁₅ = ζ ₁₆ , ..., ζ ₂₁ = ζ ₂₂ , ζ
_{Since 23} = ζ ₂₄ , ζ ₂₅ = ζ ₂₆ , and so on, ε ₁₁ = ε ₁₂ , ε ₁₃ = ε ₁₄ , naturally in the Z direction component (sub-scanning direction component) of the shift amount. ε ₁₅ = ε ₁₆ , ・ ・ ・, ε
₂₁ = ε ₂₂ , ε ₂₃ = ε ₂₄ , ε ₂₅ = ε ₂₆ ,. Therefore, the Z-direction component of the shift amount (sub-scanning direction component)
Becomes the same amount for the pair of the semiconductor laser and the collimator lens which are symmetrically positioned with respect to the emission axes a1 and a2, and it is possible to prevent the desired pitch from becoming asymmetric on the surface to be scanned. It should be noted that this relationship does not collapse even if each light source unit is further rotated in this state.

Next, in the case of the three-beam light source unit as shown in FIG. 4, the difference from the four-beam light source unit is that the configuration of the first light source section is different, as can be seen in FIG.
In the first light source unit LD1, the semiconductor laser 12 is placed on the emission axis.
1, a collimating lens 122 is arranged and a supporting member 123
Supported by. Further, the second light source unit LD2 is provided with two semiconductor lasers 111 and 112 and two collimator lenses 114 and 115 arranged symmetrically with respect to the emission axis and supported by the support member 113.

FIG. 9 shows the arrangement of the beam spots on the surface to be scanned when the above three-beam light source unit is mounted on the optical scanning device having the configuration shown in FIG. The adjustment of the sub-scanning beam pitch P is performed by the support member 11 of the second light source unit LD2 so that the beam spot distance between the LD2-R and LD2-L by the light beam from the second light source unit LD2 becomes 2P.
It suffices to fix the first light source unit LD1 to the base member 201 with the inclinations of 3 aligned, and no adjustment is necessary when fixing the first light source unit LD1. In the case of this example as well, the second light source unit L
The shift amounts δ ₁₁₁ and δ ₁₁₂ of the semiconductor lasers 111 and 112 of D2 with respect to the optical axis of the collimator lens are the same (δ ₁₁₁ =
δ ₁₁₂ ) has been adjusted.

It is also possible to increase the number of semiconductor lasers and collimator lenses for each light source section and arrange and hold three or more semiconductor lasers and collimator lenses. Similar to the first light source unit in the beam light source unit, an odd number of semiconductor lasers and collimator lenses are arranged in the main scanning direction, and the semiconductor lasers and collimator lenses located at the center are arranged on the emission axis to support them. It may be integrally supported by a member, or if it is an even number, similarly to the second light source unit, an even number of semiconductor lasers and collimator lenses are arranged symmetrically with respect to the emission axis in the main scanning direction to support them. The members may be integrally supported. In addition, when arraying and holding three or more semiconductor lasers and collimating lenses for each light source unit,
For the pair of the semiconductor laser and the collimator lens that are symmetric with respect to the emission axis, it is advisable to adjust the shift amounts of the semiconductor laser from the optical axis of the collimator lens to be the same.

The multi-beam light source device described above is mounted as a light source of the multi-beam optical scanning device having the configuration shown in FIG. 3, but the configuration, operation, and beam pitch in the sub-scanning direction of the multi-beam optical scanning device are mounted. Since the detection and correction methods of 1 have already been described in the first embodiment, the description thereof will be omitted here.

[0057]

As described above, in the invention according to the first aspect, an even number of semiconductor lasers and an even number of collimating lenses that are provided in pairs with the semiconductor lasers and that convert the light beams from the semiconductor lasers into parallel light beams are provided. A first member having a support member for arranging the even number of semiconductor lasers and the collimator lens symmetrically with respect to the emission axis in the main scanning direction and integrally supporting them.
Light source section, a second light source section configured in the same manner as the first light source section, and a beam combining means for emitting the light beams of the first and second light source sections in the sub-scanning direction in close proximity to each other. In the multi-beam light source device, the emission axis of the first light source unit and the emission axis of the second light source unit are arranged so as to be separated from each other by a predetermined angle in the main scanning direction. Since the deviation of the exit axis after beam combining due to the angle error of the combining prism etc. can be absorbed by adjustment, the component accuracy and the adjustment accuracy when fixing the collimator lens can be eased,
A multi-beam light source unit with good productivity can be provided.

According to the second aspect of the present invention, an odd number of semiconductor lasers, an odd number of collimator lenses which are provided in pairs with the semiconductor lasers, and collimate the light beam from the semiconductor lasers into a parallel light flux, and the odd number of semiconductor lasers and the collimator. A first light source unit having a lens arranged in the main scanning direction and a semiconductor laser located at the center thereof arranged on the emission axis to integrally support them; an even number of semiconductor lasers; An even number of collimator lenses, which are provided in pairs with the semiconductor laser and convert the light beam from the semiconductor laser into a parallel light flux, and the even number of semiconductor lasers and the collimator lens are arranged symmetrically with respect to the emission axis in the main scanning direction, and these are integrated. A second light source section having a supporting member for supporting the first and second light source sections, and a beam combining means for emitting the light beams of the first and second light source sections in the sub-scanning direction in close proximity to each other. In multi-beam light source apparatus, by which deployed as spaced a predetermined angle in the main scanning direction and the injection axis of the injection axis and the second light source section of the first light source,
Since the deviation of the exit axis after beam combining due to the positional accuracy between the light source parts and the angle error of the beam combining prism, etc. can be absorbed by adjustment, the accuracy of parts and the adjustment accuracy when fixing the collimator lens can be eased, resulting in good productivity. A multi-beam light source unit can be provided.

In the invention according to claim 3, in the multi-beam light source device according to claim 1 or 2,
A holding member for holding the second light source section and the beam combining means in a substantially integrated module is provided, and the holding member is used to collect a plurality of light beams from the multi-beam light source device on the surface to be scanned. A beam spot to form a beam spot to scan in the main scanning direction) and is rotatably supported by an optical axis (rotational reference) C of the scanning optical means with respect to the scanning optical means. Since the emission axis of the light source unit and the emission axis of the second light source unit are arranged symmetrically with respect to the optical axis C in the main scanning direction, the light source unit is assembled and then attached to the optical unit of the optical scanning device. However, since the beam pitch can be corrected to a predetermined beam pitch, the assembling efficiency is improved, the replacement can be performed only with the light source unit, and the repair cost can be reduced.

In the multi-beam light source device having the above-described structure, if there is a difference between the expansion coefficient of the support member and the expansion coefficient of the base member due to the change in environmental temperature, the one with the higher expansion coefficient is distorted (flexed). ) The emission direction (angle) of the beam may change and the fluctuation of the beam pitch may be amplified.
In the invention according to claim 4, since the material of the supporting member of the first and second light source portions and the material of the base member of the holding member to which the supporting member is fixed are made the same, expansion due to environmental temperature change Since the rate is the same and no distortion (deflection) occurs, only a parallel movement that has a relatively small effect on the beam pitch is required, and stable image formation can be performed over time.

According to a fifth aspect of the present invention, in the multi-beam light source device according to the third aspect, the distance between the emission axes of the first and second light source sections on the surface to be scanned is set to the beam spot from each light source section. By setting the distance to be ¼ or less of the adjacent intervals, even if there is an inclination of the scanning line due to an arrangement error of the toroidal lens in the scanning optical means, environmental temperature fluctuation, or the like,
Since the horizontal direction of the light source unit can be corrected to a predetermined beam pitch accordingly, the assembly efficiency is improved, and stable image formation can be performed over time.

According to a sixth aspect of the present invention, in the multi-beam light source device according to the third aspect, the holding member is provided with a positioning means that is rotatable about an optical axis (rotational reference) C as a center of rotation. Since the second light source unit is provided with the positioning means that is rotatable about the emission member with respect to the holding member, the beam pitch in the sub-scanning direction can be set only by adjusting the rotation of the three axes. The work can be simplified and the assembly efficiency can be improved.

In the invention according to claim 7, an even number of semiconductor lasers, an even number of collimating lenses which are provided in pairs with the semiconductor lasers and collimate a light beam from the semiconductor lasers into a parallel luminous flux, and the even number of semiconductor lasers. And a collimator lens symmetrically arranged in the main scanning direction with respect to the emission axis, and a support member integrally supporting them, and a second light source configured in the same manner as the first light source unit. And a beam synthesizing means for emitting the light beams of the first and second light source parts in close proximity to each other in the sub-scanning direction, the multi-beam light source device comprising: an emission axis of the first and second light source parts. With respect to the pair of the semiconductor laser and the collimator lens which are symmetrical with respect to each other, the shift amount from the optical axis of the collimator lens of the semiconductor laser is the same amount, so that the asymmetry of the sub-scanning beam pitch is reduced. It is possible to obtain a scan line,
To provide a multi-beam light source device capable of performing high-quality image recording, in which sub-scanning scanning line intervals on a surface to be scanned are maintained at equal intervals and stable image formation can be performed even over time. You can

In the invention according to claim 8, an odd number of semiconductor lasers, an odd number of collimator lenses which are provided in pairs with the semiconductor lasers and convert a light beam from the semiconductor lasers into a parallel luminous flux, and the odd number of semiconductor lasers. And a collimator lens are arranged in the main scanning direction, a semiconductor laser located at the center thereof is arranged on the emission axis, and a supporting member integrally supporting them is provided, and an even number of semiconductor lasers are provided. And an even number of collimator lenses that are provided as a pair with the semiconductor laser and convert the light beam from the semiconductor laser into a parallel light flux, and the even number of semiconductor lasers and the collimator lenses are arranged symmetrically with respect to the emission axis in the main scanning direction. A second light source unit having a support member that integrally supports these;
In a multi-beam light source device including a beam synthesizing means for emitting the light beams of the second light source unit in close proximity to each other in the sub-scanning direction, the multi-beam light source device is located symmetrically with respect to the emission axes of the first and second light source units. For the pair of the semiconductor laser and the collimator lens, since the shift amount from the optical axis of the collimator lens of the semiconductor laser is the same amount, it is possible to obtain the scanning line in which the asymmetry of the sub-scanning beam pitch is reduced. It is possible to provide a multi-beam light source device capable of performing high-quality image recording in which the above-described sub-scanning scanning line intervals are maintained at equal intervals and stable image formation can be performed over time.

According to a ninth aspect of the invention, in the multi-beam light source device according to the seventh or eighth aspect, the shift of the semiconductor laser from the optical axis of the collimating lens is a plurality of semiconductor lasers supported by the first light source section. The main light beam emitted from the laser beam crosses the emission axis of the first light source unit in the main scanning direction in the vicinity of the rotary polygon mirror of the optical scanning device, and is emitted from the plurality of semiconductor lasers supported by the second light source unit. Since the chief ray is set so as to intersect the emission axis of the second light source unit in the main scanning direction in the vicinity of the rotary polygon mirror of the optical scanning device, the main beam of the light beam incident on the reflecting surface of the rotary polygon mirror is set. The problem of asymmetry of the sub-scanning beam pitch can be improved while minimizing the variation in the scanning direction, and the inner diameter of the rotary polygon mirror can be minimized.

In the invention according to claim 10, claims 7 and 8 are provided.
Alternatively, in the multi-beam light source device according to the ninth aspect, since the emission axis of the first light source section and the emission axis of the second light source section are arranged so as to be separated from each other in the main scanning direction, arrangement accuracy between the light source sections is improved. It is possible to provide a light source unit with high productivity by absorbing the deviation of the emission axis after beam combining due to the angle error of the prism and the prism by adjustment, and relaxing the component accuracy and the adjustment accuracy when fixing the collimator lens.

According to the invention of claim 11, claim 7,
8. The multi-beam light source device according to 8, 9, or 10, wherein a holding member that holds the first and second light source units and the beam synthesizing means as a module by substantially integrating them is provided.
(A plurality of light beams from the multi-beam light source device are condensed on the surface to be scanned to form a beam spot and scanning is performed in the main scanning direction) Optical axis of the scanning optical means (rotation reference) with respect to the scanning optical means The first light source section and the second light source section are independently rotatable with respect to the holding member, while being rotatably supported about C as a rotation center. Thus, the sub-scanning beam pitch can be adjusted only by adjusting the rotation, so that the work can be simplified and the assembling efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention and is a perspective view showing a schematic configuration of a 4-beam multi-beam light source device in an exploded state.

FIG. 2 is an explanatory diagram of a main part configuration of the 4-beam multi-beam light source device shown in FIG. 1, in which FIG. FIG. 3B is a diagram showing a state in which four semiconductor lasers of the multi-beam light source device are arranged when viewed from the back side in the X direction.

FIG. 3 is a structural explanatory view showing an outline of an optical scanning device equipped with the multi-beam light source device shown in FIG. 1 as a light source unit.

FIG. 4 is a view showing another embodiment of the present invention and is a perspective view showing a schematic configuration of a three-beam multi-beam light source device in an exploded state.

5 is a diagram showing an example of an array of beam spots on a surface to be scanned and an example of a beam pitch adjusting method in the sub-scanning direction when the multi-beam light source device for four beams shown in FIGS.

6 is an example of an array of beam spots on a surface to be scanned when the 3-beam multi-beam light source device shown in FIG. 4 is used,
It is a figure which shows an example of the beam pitch adjustment method of a subscanning direction.

FIG. 7 is another explanatory diagram of the main part configuration of the 4-beam multi-beam light source device shown in FIG. 1, in which (a) is parallel to the X and Y directions of the first light source part of the multi-beam light source device. FIG. 6B is a diagram showing a cross-sectional state, and FIG. 6B is a diagram showing arrangement positions when four semiconductor lasers of the multi-beam light source device are viewed from the back side in the X direction.

FIG. 8 is a diagram showing an example of an array of beam spots on a surface to be scanned and an example of a beam pitch adjusting method in the sub-scanning direction when the multi-beam light source device of four beams shown in FIGS.

9 is an arrangement example of beam spots on a surface to be scanned when the 3-beam multi-beam light source device shown in FIG. 4 is used,
It is a figure which shows another example of the beam pitch adjustment method of a subscanning direction.

FIG. 10 is an explanatory diagram of a shift amount of each semiconductor laser of the first and second light source units in the 4-beam multi-beam light source device from the optical axis of the collimator lens.

FIG. 11 is a collimator lens of each semiconductor laser of the first and second light source units in the multi-beam light source device in which the first and second light source units both have an even number of two or more semiconductor lasers and collimator lenses arranged and held. It is explanatory drawing of the shift amount from an optical axis.

FIG. 12 is a diagram showing an example of conventional beam combining means.

[Explanation of symbols]

101, 102, 111, 112, 121: Semiconductor lasers 103, 113, 123: Support members 104, 105, 114, 115, 122: Collimating lens 201: Base member (holding member) 202: Beam combining prism (beam combining means) 203: Holder (holding member) 301: Multi-beam light source unit 302: Cylinder lens 303: Polygon mirror 304: fθ lens 305: Synchronization detection mirror 306: Synchronization detection sensor 307: Folding mirror 308: Toroidal lens 309: Photoconductor 309a: Surface to be scanned 310: Pulse motor 311: Pitch calculator 312: Motor controller LD1: First light source unit LD2: Second light source unit

Claims (11)

(57) [Claims] 1. A plurality of light beams used as the above-mentioned light source in an optical scanning device for converging a light beam from a light source on a surface to be scanned by a scanning optical means to form a beam spot and scanning in the main scanning direction. Which is an even number of semiconductor lasers, an even number of collimator lenses which are provided in pairs with the semiconductor lasers to collimate a light beam from the semiconductor lasers into a parallel light flux, and the even number of semiconductor lasers and collimator A first light source unit having a lens and a supporting member that symmetrically arranges the lenses in the main scanning direction with respect to the emission axis and integrally supports the lenses; and a second light source unit configured similarly to the first light source unit. A multi-beam light source device comprising a beam combining means for emitting the light beams of the first and second light source parts in close proximity to each other in the sub-scanning direction, the emission axis of the first light source part and the second light source part. Multi-beam light source apparatus characterized by the injection shaft is deployed as spaced a predetermined angle in the main scanning direction. 2. A plurality of light beams used as the light source in an optical scanning device for converging a light beam from a light source on a surface to be scanned by a scanning optical means to form a beam spot and scanning in the main scanning direction. A multi-beam light source device, wherein an odd number of semiconductor lasers, an odd number of collimator lenses which are provided in pairs with the semiconductor lasers and convert the light beam from the semiconductor lasers into a parallel light beam, and the odd number of semiconductor lasers and collimator A first light source unit having a lens and a support member that integrally arranges the semiconductor lasers arranged at the center thereof in the main scanning direction on the emission axis and integrally supports them; and an even number of semiconductor lasers, Mainly includes an even number of collimator lenses which are provided in pairs with the semiconductor laser and convert the light beam from the semiconductor laser into a parallel light flux, and the even number of semiconductor lasers and collimator lenses. A second light source section having a support member that is arranged symmetrically with respect to the emission axis in the scanning direction and integrally supports them, and the light beams of the first and second light source sections are emitted close to each other in the sub-scanning direction. In the multi-beam light source device including the beam synthesizing means, the emission axis of the first light source section and the emission axis of the second light source section are arranged so as to be separated by a predetermined angle in the main scanning direction. Multi-beam light source device. 3. The multi-beam light source device according to claim 1, further comprising a holding member for holding the first and second light source units and the beam synthesizing means in a substantially integrated module. An optical axis of the holding optical member of the scanning optical means (for scanning a plurality of light beams from the multi-beam light source device on the surface to be scanned to form a beam spot and scanning in the main scanning direction) It is rotatably supported with a rotation reference C as the center of rotation, and the emission axis of the first light source section and the emission axis of the second light source section are symmetrical with respect to the optical axis C in the main scanning direction. The multi-beam light source device is characterized by being installed so that 4. The multi-beam light source device according to claim 3, wherein the materials of the supporting members of the first and second light source parts are:
A multi-beam light source device, wherein the material of the base member of the holding member to which the support member is fixed is the same. 5. The multi-beam light source device according to claim 3, wherein the emission axis intervals of the first and second light source sections on the surface to be scanned are set to 1 times the intervals between adjacent beam spots from each light source section. A multi-beam light source device characterized by being set to / 4 or less. 6. The multi-beam light source device according to claim 3, wherein the holding member is rotatable about the optical axis (rotational reference) C as a rotation center, and first and second light sources. A multi-beam light source device, characterized in that it has a positioning means that is rotatable with respect to the holding member with respect to the holding member about an emission axis. 7. A plurality of light beams are used as the light source in an optical scanning device for converging a light beam from a light source on a surface to be scanned by a scanning optical means to form a beam spot and scanning in the main scanning direction. Which is an even number of semiconductor lasers, an even number of collimator lenses which are provided in pairs with the semiconductor lasers to collimate a light beam from the semiconductor lasers into a parallel light flux, and the even number of semiconductor lasers and collimator A first light source unit having a lens and a supporting member that symmetrically arranges the lenses in the main scanning direction with respect to the emission axis and integrally supports the lenses; and a second light source unit configured similarly to the first light source unit. A multi-beam light source device comprising the beam combining means for emitting the light beams of the first and second light source parts in the sub-scanning direction in close proximity to each other, with respect to the emission axes of the first and second light source parts. The pair of semiconductor laser and a collimator lens in the referred position, the multi-beam light source and wherein the shift amount from the collimating lens optical axis of the semiconductor laser is the same amount. 8. A plurality of light beams used as the light source in an optical scanning device for converging a light beam from a light source on a surface to be scanned by a scanning optical means to form a beam spot and scanning in the main scanning direction. A multi-beam light source device, comprising: an odd number of semiconductor lasers; an odd number of collimator lenses provided in pairs with the semiconductor lasers to collimate a light beam from the semiconductor lasers into a parallel light beam; A first light source unit having a lens and a support member that integrally arranges the semiconductor lasers arranged at the center thereof in the main scanning direction on the emission axis and integrally supports them; and an even number of semiconductor lasers, Mainly includes an even number of collimator lenses which are provided in pairs with the semiconductor laser and convert the light beam from the semiconductor laser into a parallel light flux, and the even number of semiconductor lasers and collimator lenses. A second light source unit having a support member that is arranged symmetrically with respect to the emission axis in the scanning direction and integrally supports them, and emits the light beams of the first and second light source units close to each other in the sub-scanning direction. In the multi-beam light source device including the beam combining means, the pair of the semiconductor laser and the collimator lens at positions symmetrical with respect to the emission axes of the first and second light source sections are arranged from the optical axis of the collimator lens of the semiconductor laser. A multi-beam light source device having the same shift amount. 9. The multi-beam light source device according to claim 7, wherein the shift of the semiconductor laser from the optical axis of the collimating lens is a principal ray emitted from a plurality of semiconductor lasers supported by the first light source section. Is a main beam emitted from a plurality of semiconductor lasers supported by the second light source unit, which crosses the emission axis of the first light source unit in the main scanning direction in the vicinity of the rotary polygon mirror of the optical scanning device. A multi-beam light source device, characterized in that the multi-beam light source device is set so as to intersect the emission axis of the second light source part in the main scanning direction in the vicinity of the rotary polygon mirror of the device. 10. The multi-beam light source device according to claim 7, 8 or 9, wherein the emission axis of the first light source section and the emission axis of the second light source section are arranged so as to be separated from each other in the main scanning direction. A multi-beam light source device characterized by the above. 11. The multi-beam light source device according to claim 7, 8, 9 or 10, further comprising a holding member for substantially integrally modularizing and holding the first and second light source sections and the beam combining means. The holding member is provided with respect to the scanning optical means (scanning in the main scanning direction by converging a plurality of light beams from the multi-beam light source device on the surface to be scanned to form a beam spot). Optical axis (rotation standard) C
Is rotatably supported with respect to the holding member, and the first light source unit and the second light source unit are independently rotatable with respect to the holding member about their respective emission axes. Characteristic multi-beam light source device.