JPH1123988A - Multi-beam light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a multi-beam light source device having a simple configuration and an excellent aging stability and to make it possible to easily adjust beam spot intervals. SOLUTION: This light source device has a light source part comprising a plurality of semiconductor laser 101, 102, a plurality of collimator lenses 104, 105 being paired with the semiconductor laser 101, 102 and collimating each light beam into a parallel light flux, and a holding member 103 arranging a plurality of the semiconductor laser 101, 102 and the collimator lenses 104, 105 in a direction of a main scanning and holding them in one body. And, the above semiconductor distance D and the collimator distance d have a relation of D/d>1, and also the above light source part is held so as to be positioned in a direction of rotation making an emitting axis as a rotary axis. Thus, it is possible to maintain the relative positions against environmental changes even by combination of general use semiconductors and also keep a stable optical axis accuracy and further make sub-scanning directional pitches adjustable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a digital copying machine,
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device used in a writing system of a recording device such as a laser printer and a laser facsimile, and more particularly to a light source of a multi-beam optical scanning device in which a photosensitive member is simultaneously scanned with a plurality of light beams to greatly improve a recording speed. The present invention relates to a multi-beam light source device used as a light source.

[0002]

2. Description of the Related Art As a means for improving a recording speed in an optical scanning apparatus used in a writing system of a recording apparatus such as a digital copying machine, a laser printer, and a laser facsimile, a rotating polygon mirror as a deflecting means is rotated. There are ways to increase speed. However, in this method, the durability of the motor, noise and vibration, the modulation speed of the semiconductor laser, and the like are problematic, and the recording speed is limited. Therefore, there has been proposed a multi-beam optical scanning apparatus in which a plurality of laser beams are scanned at a time to record a plurality of lines at the same time, thereby improving a recording speed. As an example, a method of combining light beams 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.

In the above-described semiconductor laser array, although there are a plurality of light sources, a sensor for detecting the output is common,
Although the light output cannot be fed back in real time as in a normal semiconductor laser, the light output is apt to fluctuate due to the crosstalk due to the close proximity of the light source, and high-precision light quantity control cannot be performed. In addition, it has a disadvantage of being expensive due to its specialty. These are disadvantageous as the number of light sources increases. On the other hand, a method of using a plurality of general-purpose semiconductor lasers and synthesizing light beams from the plurality of semiconductor lasers does not have the above-described problem, but requires improvement in environmental stability and handling.

[0004]

As a multi-beam optical scanning device, light beams from two semiconductor lasers are combined, and the two beams are simultaneously scanned by a deflecting means such as a rotating polygon mirror.
A method of recording adjacent lines is known, but recently, higher speed and higher density are required, and three beams and four beams are required. Therefore, a semiconductor laser array has been proposed that uses a semiconductor laser array as a light source to cope with the problem.However, as described above, the semiconductor laser array has limitations in terms of control and can be handled in the same manner as a general-purpose semiconductor laser. Not suitable for high-precision output control,
Despite the fact that the collimator lens is common despite the fact that there are multiple light sources, the wavelength difference between the light sources and the difference between the light emitting point positions remain, the image forming position is shifted, and the beams emitted from the collimator lens are separated from each other. Handling is troublesome, such as diverging in the direction.

On the other hand, in the case of a multi-beam light source device that combines two or more general-purpose semiconductor lasers and uses a beam splitter or a prism to combine beams, it is necessary to combine the beam splitters and prisms in a plurality of stages and combine one beam at a time. In addition, there are disadvantages that the structure becomes complicated and that it is difficult to perform the alignment operation of each beam and maintain the beam spot interval. In addition, as the structure becomes more complicated, the accumulation of errors increases, and each component requires higher accuracy. In order to correct the beam position shift over time, means for detecting and correcting the beam position is required. It is disadvantageous in terms of cost.

The present invention has been made in view of the above circumstances. In the present invention, even when a beam is split by a beam splitter using two or more general-purpose semiconductor lasers,
There is no need to provide a beam splitter or the like in a plurality of stages, and a multi-beam light source device having excellent stability over time can be realized with a simple configuration, and the interval between beam spots (setting of the scanning line interval in the sub-scanning direction) can be easily performed. The purpose is to be.

In recent years, recording apparatuses have become multi-functional, and a function for selecting a recording density according to the application is incorporated. To vary the recording density in the above-described multi-beam writing system, In addition to the modulation speed of the polygon motor and the semiconductor laser, it is necessary to change the scanning line interval in the sub-scanning direction.

Accordingly, an object of the present invention is to provide a multi-beam light source device which can easily and reliably switch the scanning line interval in the sub-scanning direction. It is a further object of the present invention to provide a multi-beam light source device capable of increasing the number of beams with a minimum light emission output without loss of light quantity.

[0009]

According to a first aspect of the present invention, there is provided a multi-beam light source device, comprising: a plurality of semiconductor lasers; A light source unit having a plurality of collimating lenses, and a support member for arranging the plurality of semiconductor lasers and the plurality of collimating lenses in the main scanning direction and integrally supporting the plurality of semiconductor lasers and the plurality of collimating lenses; The distance d has a relationship of D / d> 1, and the light source is supported so as to be positionable in a rotation direction about the emission axis as a rotation axis.

The multi-beam light source device according to claim 2 is
A semiconductor laser, a collimating lens that converts a light beam from the semiconductor laser into a parallel light beam, and a support member that arranges the semiconductor laser and the collimating lens on an emission axis and integrally supports the semiconductor laser and the collimating lens. A light source unit, a plurality of semiconductor lasers, and a plurality of collimating lenses that are provided in pairs with the semiconductor lasers and convert each light beam into a parallel light beam;
A second light source unit having a plurality of semiconductor lasers and a plurality of collimating lenses arranged symmetrically with respect to an emission axis and a support member for integrally supporting the plurality of semiconductor lasers and the plurality of collimating lenses; and light beams of the first and second light source units And a beam synthesizing means for emitting the light in close proximity to each other.

[0011] According to a third aspect of the present invention, there is provided a multi-beam light source device.
A plurality of semiconductor lasers, a plurality of collimating lenses provided in pairs with the semiconductor lasers to convert each light beam into a parallel light beam, and the plurality of semiconductor lasers and the plurality of collimating lenses symmetrically with respect to the emission axis in the main scanning direction. A first light source unit having a support member arranged and supporting them integrally, a second light source unit configured similarly to the first light source unit, and light from the first and second light source units. And a beam synthesizing means for projecting the beams close to each other.

According to a fourth aspect of the present invention, there is provided a multi-beam light source device.
4. The multi-beam light source device according to claim 3, wherein one of the first and second light source units is 2N.
.. (N = 1, 2,...) Of semiconductor lasers and a collimating lens. By making the ratio D / d different from the collimating lens interval d, the beam spot interval L from the other light source unit having N semiconductor lasers is set to N + 1 times.

According to a fifth aspect of the present invention, there is provided a multi-beam light source device.
2N + 1 (odd number) (N = 1, 2,...) Semiconductor lasers, a collimator lens provided in pairs with the semiconductor lasers to convert each light beam into a parallel light beam, and a collimator with the 2N + 1 semiconductor lasers A first light source unit having a lens and a support member for symmetrically arranging the optical axis of the semiconductor laser positioned at the center thereof with respect to the emission axis and integrally supporting them, and 2N or 2N + 2 (Even number) semiconductor lasers, a collimating lens provided in pairs with the semiconductor lasers to convert each light beam into a parallel light beam, and the 2N or 2N + 2 semiconductor lasers and the collimating lens are symmetrical with respect to the emission axis in the main scanning direction. A second light source unit having a supporting member disposed integrally and supporting them integrally, and a beam combining unit that emits light beams from the first and second light source units in close proximity to each other. And it is characterized in that comprising the stages.

According to a sixth aspect of the present invention, there is provided a multi-beam light source device.
The multi-beam light source device according to any one of claims 2 to 5, wherein the beam combining means emits light with the emission axis of the second light source unit coincident with the emission axis of the first light source unit. It is characterized by the following.

According to a seventh aspect of the present invention, there is provided a multi-beam light source device.
The multi-beam light source device according to any one of claims 2 to 6, wherein the first and second light source units and the beam synthesizing unit are substantially integrally modularized and detachable from the optical housing. The first light source unit is rotatably supported by using the emission axis of the first light source unit as a rotation axis.

The multi-beam light source device according to claim 8 is
8. The multi-beam light source device according to claim 2, wherein the beam combining means collectively sets the phases of the polarization directions of the plurality of beams for one of the first and second light source units. A half-wave plate for converting by
It is characterized by comprising a polarizing beam splitter which emits a plurality of beams that have passed through a two-wavelength plate and a beam from the other light source unit together.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail based on illustrated embodiments.

FIG. 1 is an explanatory view of the configuration of a multi-beam light source device according to an embodiment of the present invention, and shows a four-beam light source unit using a total of four general-purpose semiconductor lasers. In FIG. 1, semiconductor lasers 101 and 102 are provided in fitting holes (not shown) formed in parallel in the main scanning direction (Y direction in the drawing) at 6 mm intervals on the back side of a support member 103 made of aluminum die cast. Each is pressed and supported. The collimating lenses 104 and 105 provided as a pair with the semiconductor lasers 101 and 102 are arranged so that the divergent light beams of the respective semiconductor lasers 101 and 102 become parallel light beams.
The semiconductor lasers 101 and 1 are aligned in the Y and Z directions so as to be in a predetermined beam emission direction.
An adhesive is filled in a gap between the U-shaped support portions 103-1 and 103-2 of the support member 103 formed in a pair with the fitting hole of No. 02 to be fixed, thereby forming the first light source portion LD 1. The second light source section LD2 also includes semiconductor lasers 106 and 107, collimating lenses 108 and 109, and a support member 103 ', and has the same configuration as the first light source section LD1.
In the above embodiment, the semiconductor laser 1 is supported by the support member 103.
01, 102 and the collimating lenses 104, 105 are directly supported, and the semiconductor lasers 106, 10 are supported by the supporting member 103 '.
7. Although the example in which the collimating lenses 108 and 109 are directly supported has been described, the supporting member may be supported with a member for holding the semiconductor laser or a member for holding the collimating lens interposed therebetween. The member and the support member are desirably the same material or a material having equivalent thermal characteristics.

FIG. 2A shows X, X of the first light source section of the multi-beam light source unit in which the first light source section LD1, the second light source section LD2, and the beam combining prism 111 are incorporated in the holder 110. A state of a cross section parallel to the Y direction is shown. The semiconductor lasers 101 and 102 and the collimating lenses 104 and 105 correspond to the emission axis a of the first light source unit.
Semiconductor lasers 101 and 102
The distance d between the collimating lenses 104 and 105 is set to be smaller (D / d> 1) with respect to the distance D (i.e., the optical axes of the collimating lenses 104 and 105 are eccentrically arranged in the Y direction toward the emission axis a). , And is fixed to the U-shaped support portions 103-1 and 103-2 of the support member 103 with an adhesive 113). As a result, the laser beams from the semiconductor lasers 101 and 102 are emitted by the collimating lenses 104 and 105 at an angle of α in the crossing direction.

The first light source section LD1 is brought into close contact with a reference surface provided on the back surface of the holder 110 by aligning the emission axis a with the center a 'of the cylindrical section 110-1 serving as the rotation reference of the holder 110. Screw 114 passed from the front side of
Is fixed by The second light source unit LD2 is also configured in the same manner as the first light source unit LD1, and the emission beam of the entire light beam is adjusted by the beam combining prism 111 so that the emission axis is aligned with the emission axis a of the first light source unit LD1. Are emitted adjacent to each other. The beam combining prism 111 is fitted and fixed from behind the holder 110 before the first and second light source units are attached.

Here, as shown in FIG. 2B, the first light source section LD1 is inclined by θ from the main scanning direction (Y direction) to the sub-scanning direction (Z direction) about the emission axis a as the center of rotation. By adjusting the tilt amount θ, the beam spot interval in the sub-scanning direction on the surface to be scanned such as the photoconductor can be adjusted. Further, the beam spot interval in the sub-scanning direction can be similarly adjusted for the second light source section LD2. Since the first light source section LD1 and the second light source section LD2 have the same beam spot interval L, the main scanning direction (Y direction) to the sub-scanning direction (Z direction) with the emission axis a (= a ′) as the center of rotation. The first light source as shown in FIG. 5 is set by setting the tilt amount θ of the first light source unit to θ1 and the tilt amount of the second light source unit to be different from θ2. Beam spots LD1-L and LD1-R on the photoreceptor surface of the unit LD1 and two beam spots LD2 of the second light source unit LD2.
Two beam spots LD2-L and LD2-R are equally spaced pitch P (recording density pitch) in the sub-scanning direction (Z direction).
It can be adjusted so that

Further, the above-mentioned d / D is changed between the first light source section LD1 and the second light source section LD2 to change the emission angle α of each beam.
The pitch P can be obtained at an equal interval in the sub-scanning direction on the surface of the photoreceptor by changing. In this case, since the relationship L = f (α) between the emission angle α and the beam spot interval L on the photosensitive member surface is not uniform (linear) by the imaging optical system, the first light source LD1 and the second light source LD2 for the emission angle α. Although the ratio with respect to the light source unit LD2 cannot be defined, the distance between the two beam spots of the second light source unit LD2 is 3 · L with respect to the distance L between the two beam spots on the photoconductor surface of the first light source unit LD1. The first light source unit LD1 has the same inclination amount θ from the main scanning direction to the sub-scanning direction about the emission axis a (= a ′) of the first light source unit LD1 and the second light source unit LD2 as the center of rotation. By arranging the beam spots of the second light source section LD2 on a straight line as shown in FIG. 6, the pitch P (recording density pitch) is equally spaced in the sub-scanning direction.

In this manner, the beam spots LD1-R and LD1-L of the first light source section LD1 and the beam spots LD2-R and LD2-L of the second light source section LD2 are arranged on the same straight line. Then, the injection shaft a is attached to the holder 110.
By rotating along the central axis a 'of the cylindrical portion 110-1, the pitch P can be changed in proportion thereto. In the case of a configuration in which the beam spots are arranged as shown in FIG. 6, the cylindrical portion 110-1 of the holder 110 shown in FIG.
Is rotatably held by a holding member (not shown),
The pitch P can be easily adjusted by providing a mechanism for rotating the holder 110 by moving the lever 110-2 provided on the side wall of the holder 10 upward or downward.

The beam combining prism 111 shown in FIG.
Has a polarizing beam splitter surface 111-1 therein, a half-wave plate (λ / 2 plate) 112 provided on the incident surface of the beam from the second light source unit LD2, and a second light source unit L
A reflection surface 111-2 for reflecting the beam from D2 is provided. Then, the beam from the first light source unit LD1 is transmitted through the polarization beam splitter surface 111-1 as it is and is emitted, and the second light source unit LD2
Is rotated 90 degrees by the half-wave plate 112, reflected upward on the inclined surface 111-2, further reflected on the polarization beam splitter surface 111-1, and emitted. . This makes it possible to easily combine the beams from the first and second light source units while reducing the light amount loss.

FIG. 3 is an explanatory view of the configuration of a multi-beam light source device according to another embodiment of the present invention, and shows a three-beam light source unit using a total of three general-purpose semiconductor lasers. In the three-beam light source unit shown in FIG. 3, the semiconductor laser 201 of the first light source unit LD1 is disposed at the center of the support member 203, and is supported by the collimator lens 202 with the optical axis aligned. The second light source unit LD2 includes two semiconductor lasers 204 and 205, two collimating lenses 207 and 208 provided in pairs with the semiconductor lasers to convert each light beam into a parallel light beam, and a support member 206 that supports these. The configuration is the same as that of the first and second light source units in FIG. 1 described above, and the state of the cross section parallel to the X and Y directions is shown in FIG.
Is the same as First light source section LD1, second light source section LD
2 and the beam combining prism 211 are incorporated in the holder 210, and the two beams from the second light source unit LD2 are emitted by the beam combining prism 211 with the first light source unit LD1 and the emission axis a aligned. The first light source section LD
The optical axis of one semiconductor laser 201 and the collimating lens 202 coincides with the emission axis a, and the emission axis a is aligned with the center a ′ of the cylindrical portion 210-1 serving as the rotation reference of the holder 210.

Therefore, as shown in FIG. 7, the second light source unit L1 is centered on the beam spot of the first light source unit LD1.
The tilt amount θ in the sub-scanning direction (Z direction) of D2 is adjusted to 2
By arranging the two beam spots LD2-R and LD2-L on a straight line, the pitch P at an equal interval in the sub-scanning direction is obtained.
(Recording density pitch) is obtained. According to this arrangement, the injection axis a is positioned at the center a ′ of the cylindrical portion 210-1 of the holder 210.
To the holder 21 around the injection axis a = a ′.
By adjusting the tilt amount θ by rotating 0, the pitch P can be changed in proportion thereto. A mechanism for rotatably holding the cylindrical portion 210-1 of the holder 210 with a holding member (not shown) and rotating the holder 210 by moving the lever 210-2 provided on the side wall of the holder 210 upward or downward is provided. The pitch P
Can be easily adjusted.

FIG. 4 is a diagram showing an outline of a multi-beam optical scanning apparatus using a four-beam light source unit having the same configuration as that of FIG. Each beam emitted from the light source unit 400 intersects near the reflection position of a polygon mirror 403 as a deflecting unit via a cylinder lens 402, and is deflected and scanned by the polygon mirror 403. After passing through the two-element fθ lens 404, each beam is reflected by the turning mirror 405 toward the photosensitive drum 407, is imaged on the photosensitive drum 407 by the toroidal lens 406, and has a predetermined pitch P in the sub-scanning direction. Four adjacent lines are drawn simultaneously for each beam. Also, a folding mirror 405
A mirror 408 for synchronization detection is provided outside the image area of, and the beam reflected by the mirror 408 is detected by the synchronization detection sensor 409, and the scanning start position of each beam in the main scanning direction S is detected. .

Here, the beam spots LD1-R and LD1-L of the first light source section LD1 and the second light source section LD2
The beam spots LD2-R and LD2-L of FIG.
The following describes an embodiment in which the arrangement is set as shown in FIG.
In FIG. 9, since the beams are incident in a time series, the write start timing is individually set by separating the detection signals of the respective beams. If the beam spots are not separated in the main scanning direction, first, the synchronization detection sensor 409
May be detected by delaying the beam passing by a predetermined amount and timing of another beam.

At the scanning end position near the photosensitive drum 407, a linear sensor 411 is arranged in the sub-scanning direction. For example, only two beams of the second light source section LD2 are turned on and the beam interval is set. Is measured, and even if the scanning line interval changes due to environmental changes, component replacement, etc., it is corrected so that a predetermined value is always maintained. This measurement is
In the case of the arrangement of FIG. 6, ideally, the recording pitch P is three times (3 · P). Therefore, the deviation amount of the measured value from 3 · P is calculated by the pitch calculation unit 412, and the calculation result is obtained. Is sent to the motor control unit 413, and the motor control unit 413 drives the stepping motor 414 by an angle (converted value) corresponding to the deviation, thereby pushing up the lever 410-1 provided integrally with the holder 410, or If the holder 410 of the light source unit 400 is rotated downward in the γ direction about the emission axis by pulling it down, the deviation of the recording pitch P in the sub-scanning direction can be corrected. Also, when a recording density variable signal from an operation unit or the like (not shown) is received and the recording pitch P to be set is switched, the stepping motor 414 is similarly driven by the motor control unit 413, and the recording pitch in the sub-scanning direction is changed. P is varied.

In the embodiment described above, the first and second
By aligning the emission axes a of the light source units LD1 and LD2 with each other, the beam spot is arranged symmetrically with respect to the emission axis a, and the emission axis a is rotated so as to coincide with the rotation center a 'of the holder, thereby setting the pitch P in the sub-scanning direction. It is variable, but not limited to this. As shown in FIG. 8, the first and second light source units LD1, L
The emission axes a1 and a2 of D2 are arranged symmetrically with respect to the rotation center a 'of the holder, and the first and second light source sections LD1 and LD2 are arranged.
Inclination of theta ₁ to 2 in the sub-scanning direction, by adjusting theta _2, respectively, the beam spots LD1-R, LD1-L, LD2
The pitch P can be varied by rotation about the rotation center a 'of the holder also by a method such as combining beams so that -R and LD2-L are arranged in series.

In the embodiment of FIG. 1, an example is shown in which two semiconductor lasers are used for the first light source section LD1 and the second light source section LD2, respectively. In the embodiment of FIG. The second light source section LD uses one semiconductor laser for the section LD1.
2 shows an example in which two semiconductor lasers are used.
A configuration in which more semiconductor lasers are used for the second light source unit can be employed.

FIG. 9 shows an embodiment of a configuration in which more semiconductor lasers are used for the first and second light source sections, and shows an example of an eight-beam light source unit using a total of eight general-purpose semiconductor lasers. The first light source section LD1 includes four semiconductor lasers 501, 502, 503, and 504, and collimating lenses 505, 506, 507, and 508 that are provided in pairs with the semiconductor lasers and convert each light beam into a parallel light flux. Are arranged in the main scanning direction (Y direction in the figure), and are integrally supported by a support member 509. Similarly, the second light source section LD2 also includes four semiconductor lasers 511, 512, 513, and 51.
4 and collimating lenses 515, 516, 51 provided in pairs with the semiconductor laser to convert each light beam into a parallel light beam.
7 and 518 are arranged in the main scanning direction, and are integrally supported by a support member 509. The first and second light source units and the beam combining prism 520 are configured as shown in FIG. (Not shown).

The beam combining prism 520 has a polarizing beam splitter surface 520-1 inside similarly to FIG.
A half-wave plate (λ / 2 plate) 521 is provided on the incident surface of the beam from the second light source unit LD2, and the second light source unit L
A reflection surface 520-2 for reflecting the beam from D2 is provided. The four light beams from the first light source unit LD1 pass through the polarization beam splitter surface 520-1 and exit as they are, and the second light source unit LD1
The four beams from 2 are rotated by 90 degrees by the half-wave plate 521, reflected upward on the inclined surface 520-2, further reflected on the polarization beam splitter surface 520-1, and emitted. I have. This makes it possible to easily combine a plurality of beams from the two light source units while reducing the light amount loss.

FIG. 10 shows an example of the arrangement of beam spots on the surface of the photoconductor when four semiconductor lasers are used for the first and second light source units, respectively. In this example, four beam spots LD1-R, LD1-RR, LD1-L, LD1-LL from the first light source unit LD1 in FIG.
Of the beam spots LD1-R sandwiching the emission axis a ',
Regarding the distance between the LD1 and the LD1, the distance D between the semiconductor lasers (the distance between the semiconductor lasers 502 and 503 adjacent to the emission axis a ') and the distance between the collimating lenses (the distance between the collimating lenses 506 and 507 adjacent to the emission axis a'). ) By changing the ratio D / d to d, the four beam spots LD2-R, LD2-RR,
The distance between LD2-L and LD2-LL is set to be five times the distance L, and the beam spot array of the second light source section LD2 is arranged between them. Also, the distance between the beam spots LD1-R and LD1-RR from the first light source section LD1, and L
The interval between D1-L and LD1-LL is L. By setting in this way, the beam spots of the first and second light source units can be aligned on a straight line at equal intervals L without overlapping, so that the light source unit can be connected to the emission axis a ′ (rotation of a holder (not shown)). The scanning line interval (recording density pitch) P in the sub-scanning direction can be reliably changed by a simple operation of rotating about the center.

By changing the beam spot interval between the first and second light sources at a plurality of positions, there are many other arrangement methods. However, the work becomes complicated, and the work may be confused and cause a work error. Here, a method has been described in which the number of intervals must be changed as small as possible.

FIG. 11 shows another embodiment in which more semiconductor lasers are used for the first and second light source sections. An example of a seven-beam light source unit using a total of seven general-purpose semiconductor lasers is shown. FIG. The first light source section LD1 includes three semiconductor lasers 601, 602, and 603 and collimating lenses 604, 605, and 606 provided in pairs with the semiconductor lasers and converting each light beam into a parallel light beam in the main scanning direction (see FIG. (The Y direction in the middle) and are integrally supported by a support member 607. The semiconductor laser 602 and the collimator lens 605 at the center of the first light source section LD1 are arranged on the emission axis a ', They are arranged symmetrically with respect to the injection axis a '.
The second light source section LD2 includes four semiconductor lasers 608, 6
09, 610, 611 and a collimating lens 61 provided in pairs with the semiconductor laser to convert each light beam into a parallel light flux
2, 613, 614, and 615 are arranged symmetrically with respect to the emission axis a 'in the main scanning direction and integrally supported by the support member 616. The first and second light source units and the beam combining prism 617 are integrally mounted on a holder (not shown) having a configuration as shown in FIG.

Incidentally, similarly to FIG. 1, the beam combining prism 617 has a polarizing beam splitter surface 617-1 inside thereof, and the beam incidence surface of the beam from the second light source unit LD2 has 1 /
A two-wavelength plate (λ / 2 plate) 618 is provided, and a reflection surface 617-2 for reflecting a beam from the second light source unit LD2 is provided. The three beams from the first light source section LD1 pass through the polarizing beam splitter surface 617-1 and exit as they are, and the four beams from the second light source section LD2 are 波長 wavelength. The polarization direction is rotated by 90 degrees by the plate 618, reflected upward on the inclined surface 617-2, and further reflected on the polarization beam splitter surface 617-1 and emitted. This makes it possible to easily combine a plurality of beams from the two light source units while reducing the light amount loss.

FIG. 12 shows an example of the arrangement of beam spots on the surface of the photoconductor when three semiconductor lasers are used for the first light source LD1 and four semiconductor lasers are used for the second light source LD2. Is shown. In this example, three beam spots LD1 from the first light source unit LD1 in FIG.
−R, LD1-C and LD1-L are defined as L, and four beam spots LD2-R, LD2-R,
The distance between LD2-RR, LD2-L, LD2-LL is also L, and the beam spots from the first and second light source units are alternately aligned at equal intervals.

As described above, the number of semiconductor lasers in the first and second light source units is odd (2N + 1 (N = 1, 2,...).
.)) And the even number (2N + 2)
As shown in FIG. 5, the beam spots from the first and second light source units can be alternately aligned at equal intervals, and only by rotating about the emission axis a ′ as the center of rotation, the beam spot in the sub-scanning direction is proportional to the rotation angle. The pitch P can be changed. When only one light source unit is provided, the beam spot interval L corresponds to the interval between the semiconductor lasers. Therefore, in order to make the beam spots close to each other, the size of the semiconductor laser or the collimating lens itself must be reduced to shorten the interval. 11 and 12, since the beam spots of the first and second light source units are alternately arranged, the beam spot interval of each light source unit is L (the pitch in the sub-scanning direction). 2
In P), the substantial beam spot interval after beam combining is L / 2 (pitch P in the sub-scanning direction), and the number of beams can be increased with a determined element size. Becomes possible.

In the embodiment shown in FIG. 3, the number of semiconductor lasers in the first and second light source units is odd (2N + 1).
(N = 1, 2,...)) And an even number (2N + 2) show an example of N = 0, but when N = 0, a combination of a semiconductor laser of one light source and a collimating lens Is 1
There is no need to adjust the angles θ of the first and second light source sections, and if each light source section is simply incorporated in the holder, the beam spot on the photoreceptor surface is aligned in a straight line, so that assemblability is excellent. Since the amount of eccentricity between the semiconductor laser and the collimating lens can be minimized, the conventional optical system for recording with one beam can be used as it is (only the light source unit is replaced).

In the embodiment of the present invention described above, the beam combining means collectively collects the phases of the polarization directions of a plurality of beams from the second light source unit among the first and second light source units. Beam combining prism (111, 111) having a half-wave plate for converting the beam, and a polarization beam splitter surface for emitting a combined beam of the plurality of beams passed through the half-wave plate and the beam from the first light source unit. 211,520,617)
Is used.

In order to increase the number of beams in the conventional beam combining method, for example, as shown in FIG. 13, an optical element having a plurality of beam splitter surfaces (BS surfaces) arranged in parallel is used, and the beam splitter surface is formed a plurality of times. There is a method of passing the light. Normally, the transmitted light amount and the reflected light amount are halved on the beam splitter surface, so that the beam of the first semiconductor laser LD-1 is phase-shifted in the polarization direction using a half-wave plate (λ / 2 plate). Is rotated by 90 degrees, and transmitted through the polarization beam splitter surface (polarization BS surface) that is the final combined surface, the amount of light emitted from the polarization beam splitter surface that is the final combined surface is equal to the first semiconductor laser LD-1. In the second semiconductor laser LD-2, B
Since one more light passes through the S surface, the amount of emitted light is １ ／,
Third semiconductor laser LD3 and fourth semiconductor laser LD
In the case of -4, the light passes through two more BS planes, so that the amount of emitted light becomes 1/4. As the number of beams increases, the light amount loss increases, and the output of the semiconductor laser is limited.

On the other hand, according to the beam synthesizing means of the present invention, since a plurality of beams from the first and second light source sections only pass through the polarizing beam splitter surface once, there is almost no light quantity loss and The number of beams can be increased by the light emission output of the multi-beam having a plurality of beams by using a general-purpose semiconductor laser like the three-beam, four-beam, seven-beam, and eight-beam light source units described in the embodiment. The light source device can be easily realized.

[0044]

As described above, in the multi-beam light source device according to the first aspect, a plurality of semiconductor lasers and a plurality of collimating lenses provided in pairs with the semiconductor lasers to convert each light beam into a parallel light beam are provided. A light source unit having a plurality of semiconductor lasers and a collimating lens arranged in a main scanning direction and a supporting member for integrally supporting the semiconductor lasers and the collimating lens;
d> 1 and the light source unit is supported so as to be positionable in the rotation direction with the emission axis as the rotation axis, so that the relative position of the light source unit with respect to environmental changes can be maintained even with the combination of general-purpose semiconductor lasers. A multi-beam light source device that can maintain and maintain stable optical axis accuracy and that can adjust the pitch in the sub-scanning direction can be realized.

In the multi-beam light source device according to the second aspect, a general-purpose semiconductor laser, a collimating lens for converting a light beam from the semiconductor laser into a parallel light beam, and the semiconductor laser and the collimating lens are arranged on an emission axis. A first light source unit having a support member that integrally supports
A plurality of semiconductor lasers, a plurality of collimating lenses provided in pairs with the semiconductor lasers to convert each light beam into a parallel light beam, the plurality of semiconductor lasers and a plurality of collimating lenses are arranged symmetrically with respect to an emission axis, and these are integrated. A second light source unit having a supporting member for supporting the first and second light sources, and a beam combining unit for emitting the light beams of the first and second light source units in close proximity to each other, so that the number of beams is further increased. The beam light source device can be provided in a small size and at low cost, and it is possible to cope with high-speed and high-density recording devices.

In the multi-beam light source device according to the third aspect, a plurality of semiconductor lasers, a plurality of collimating lenses provided in pairs with the semiconductor lasers to convert each light beam into a parallel light beam, the plurality of semiconductor lasers and a plurality of collimating lenses A first light source unit 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 the first and second light source units; 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 sources in close proximity to each other, thereby providing a multi-beam light source device having an increased number of beams at a small size and at low cost. Therefore, it is possible to cope with high-speed and high-density recording devices.

In the multi-beam light source device according to a fourth aspect, in the multi-beam light source device according to the third aspect, either one of the first and second light source units is 2N (even number) ( N = 1, 2,...) And a collimating lens, and a semiconductor laser interval D and a collimating lens interval d with respect to a spot interval sandwiching at least an emission axis of a plurality of beam spots from the light source unit. Is different from the ratio D / d to N + 1 times the beam spot interval L from the other light source unit having N semiconductor lasers.
The beam spots of the light source section are aligned without overlapping,
The pitch in the sub-scanning direction can be easily and reliably changed by a simple operation of rotating the light source unit.

In the multi-beam light source device according to the fifth aspect, 2N + 1 (odd number) (N = 1, 2,...) Semiconductor lasers and a pair of the semiconductor lasers are provided to convert each light beam into a parallel light beam. A supporting member for arranging the collimating lens, the 2N + 1 semiconductor lasers, and the collimating lens in the main scanning direction, symmetrically disposing the optical axis of the semiconductor laser located at the center thereof as the emission axis, and integrally supporting them. A 2N or 2N + 2 (even number) semiconductor lasers, a collimating lens provided in pairs with the semiconductor lasers to make each light beam a parallel light beam, and a collimator with the 2N or 2N + 2 semiconductor lasers A second light source unit having a support member for arranging the lenses symmetrically with respect to the emission axis in the main scanning direction and integrally supporting the lenses, and the first and second light source units And a beam synthesizing unit that emits these light beams in close proximity to each other, so that a multi-beam light source device with an increased number of beams can be provided in a small size and at low cost, and the high speed and high speed of the recording device can be provided. It can deal with densification. Also, since the beam spots of the first and second light source units are alternately arranged without overlapping, the pitch in the sub-scanning direction can be easily and reliably changed by a simple operation of rotating the light source unit. In addition, a beam spot interval of 1/2 of the element interval between the first and second light source units (the interval between the semiconductor laser and the collimating lens) can be obtained, so that the number of beams is further increased with a predetermined element size. And the size of the multi-beam light source device can be further reduced.

In the multi-beam light source device according to a sixth aspect, in the multi-beam light source device according to any one of the second to fifth aspects, the beam synthesizing means is provided with a second light beam on the emission axis of the first light source unit. Since the emission axes of the light source units are made to coincide with each other, the beam spot interval (pitch) P in the sub-scanning direction can be adjusted only by adjusting the inclination θ of the first and second light source units. The adjustment operation is simplified and the assembly efficiency is improved.

In the multi-beam light source device according to a seventh aspect, in the multi-beam light source device according to any one of the second to sixth aspects, the first and second light source units and the beam combining means are substantially integrated. Modularized and detachable from the optical housing (holder).
When the pitch in the sub-scanning direction fluctuates with time only by providing a simple driving means for rotating the holder by rotatably supporting the emission axis of the light source unit as a rotation axis. Correction and switching of recording density are possible.

In the multi-beam light source device according to the eighth aspect, in the multi-beam light source device according to any one of the second to seventh aspects, the beam synthesizing means is one of the first and second light source units. A half-wave plate that collectively converts the phase of the polarization direction of a plurality of beams for the light source unit, and emits a plurality of beams that have passed through the half-wave plate together with a beam from the other light source unit. With a polarizing beam splitter that does
The number of beams can be increased with a minimum light output, and a multi-beam light source device having a plurality of beams can be easily realized.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of the present invention, and is a perspective view showing a schematic configuration of a four-beam multi-beam light source device.

FIGS. 2A and 2B are explanatory diagrams of a main part configuration of the multi-beam light source device shown in FIG. 1, wherein FIG.
FIG. 3B is a diagram showing a cross section of the light source unit parallel to the X and Y directions, and FIG. 4B is a diagram of the semiconductor laser of the first light source unit viewed from the back side in the X direction.

FIG. 3 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.

FIG. 4 is an explanatory diagram of a configuration of an optical scanning device using the multi-beam light source device shown in FIG.

FIG. 5 is a diagram showing an example of an arrangement of beam spots on a photosensitive member surface when the four-beam multi-beam light source device shown in FIG. 1 is used.

FIG. 6 is a diagram showing another example of the arrangement of beam spots on the photoconductor surface when the four-beam multi-beam light source device shown in FIG. 1 is used.

7 is a diagram showing an example of an arrangement of beam spots on a photosensitive member surface when the three-beam multi-beam light source device shown in FIG. 3 is used.

8 is a diagram showing still another example of the arrangement of beam spots on the photosensitive member surface when the four-beam multi-beam light source device shown in FIG. 1 is used.

FIG. 9 is a view showing another embodiment of the present invention, and is a perspective view of an essential part showing a schematic configuration of an eight-beam multi-beam light source device.

10 is a diagram showing an example of an arrangement of beam spots on a photosensitive member surface when the eight-beam multi-beam light source device shown in FIG. 9 is used.

FIG. 11 is a view showing another embodiment of the present invention, and is a perspective view of an essential part showing a schematic configuration of a seven-beam multi-beam light source device.

12 is a diagram showing an example of an arrangement of beam spots on a photosensitive member surface when the seven-beam multi-beam light source device shown in FIG. 11 is used.

FIG. 13 is a diagram showing an example of a conventional beam combining means.

[Explanation of symbols]

101, 102, 106, 107, 201, 204, 2
05,501-504,511-514,601-60
3,608-611 ... semiconductor laser, 104,105,108,109,202,207,2
08,505-508,515-518,604-60
6,612-615 ... Collimate lens, 103,103 ', 203,206,509,519,
607, 616: support member, 110, 210, 410: holder (optical housing), 111, 211, 520, 617: beam combining prism (beam combining means), 111-1, 211-1,. 520-1, 617-1 ...
・ Polarization beam splitter surface, 112, 212, 521, 618... 波長 wavelength plate, 400, multi-beam light source unit, 402, cylinder lens, 403, polygon mirror, 404, fθ Lens, 405: folding mirror, 406: toroidal lens, 407: photoconductor drum, 408: mirror for synchronization detection, 409: synchronization detection sensor, 411: linear sensor, LD1 ..The first light source section, LD2... The second light source section.

Claims (8)

[Claims] 1. A plurality of semiconductor lasers, a plurality of collimating lenses provided in pairs with the semiconductor lasers to convert respective light beams into parallel light beams, and the plurality of semiconductor lasers and the plurality of collimating lenses in a main scanning direction. A light source section having a support member arranged and supporting them integrally, and D / d is set between the semiconductor laser interval D and the collimating lens interval d.
A multi-beam light source device, wherein the light source unit is supported so as to be positionable in a rotation direction about an emission axis as a rotation axis. 2. A semiconductor laser, a collimating lens for converting a light beam from the semiconductor laser into a parallel light beam, and a supporting member for arranging the semiconductor laser and the collimating lens on an emission axis and integrally supporting them. A plurality of semiconductor lasers, a plurality of semiconductor lasers, a plurality of collimating lenses provided in pairs with the semiconductor lasers to convert each light beam into a parallel light beam, and the plurality of semiconductor lasers and a plurality of collimating lenses. A second light source unit having a support member arranged symmetrically with respect to the emission axis and integrally supporting them;
A multi-beam light source device, comprising: a beam combining unit that emits a light beam of a second light source unit in close proximity. 3. A semiconductor device comprising: a plurality of semiconductor lasers; a plurality of collimating lenses provided in pairs with the semiconductor lasers to convert respective light beams into parallel light beams; and a plurality of the semiconductor lasers and a plurality of collimating lenses in a main scanning direction. A first light source unit having a support member which is arranged symmetrically with respect to the emission axis and integrally supports them, a second light source unit configured similarly to the first light source unit, 2. A multi-beam light source device, comprising: beam combining means for emitting the light beams of the two light source sections in close proximity to each other. 4. A multi-beam light source device according to claim 3, wherein one of said first and second light source units is 2N (even number) (N = 1, 2,...). ), And the ratio D / d between the semiconductor laser interval D and the collimating lens interval d is different for at least the spot interval sandwiching the emission axis of the plurality of beam spots from the light source unit. A multi-beam light source device characterized in that the beam spot interval L from the other light source unit having N semiconductor lasers is N + 1 times. 5. The method according to claim 1, wherein 2N + 1 (odd) (N = 1, 2,...)
A) a semiconductor laser, and a collimating lens provided as a pair with the semiconductor laser to convert each light beam into a parallel light beam;
A first support member having the 2N + 1 semiconductor lasers and the collimator lens arranged in the main scanning direction, symmetrically disposed with the optical axis of the semiconductor laser positioned at the center thereof as an emission axis, and integrally supporting them; Light source unit, 2N or 2N + 2 (even number) semiconductor lasers, a collimating lens provided as a pair with the semiconductor laser to convert each light beam into a parallel light beam, and the 2N or 2N + 2 semiconductor lasers and a collimating lens. A second light source unit having a support member that is symmetrically arranged with respect to the emission axis in the main scanning direction and integrally supports these, and emits light beams from the first and second light source units in proximity to each other. A multi-beam light source device comprising a beam combining means. 6. The multi-beam light source device according to claim 2, wherein said beam combining means matches an emission axis of said second light source with an emission axis of said first light source. A multi-beam light source device, which emits light. 7. The multi-beam light source device according to claim 2, wherein the first and second light source units and the beam synthesizing unit are substantially integrally modularized with respect to the optical housing. A multi-beam light source device which is detachable and rotatably supported with an emission axis of a first light source unit as a rotation axis. 8. A multi-beam light source device according to claim 2, wherein said beam combining means comprises: a polarization direction of a plurality of beams for one of said first and second light source units; And a polarizing beam splitter that emits the combined beams that have passed through the half-wave plate and the beam from the other light source unit. Characteristic multi-beam light source device.