JPS58184117A - Scanner of plural beams - Google Patents

Abstract

PURPOSE:To make a high-speed scanning possible, by providing two image forming systems having positive refracting power between a light source and a deflector. CONSTITUTION:Luminous fluxes from light emitting parts 1a and 1b of a semiconductor array laser light source 1 are condensed by an image forming lens 2, and principal light beams m1 and m2 of them overlap each other at a focus F. The luminous flux condensed near the second image forming lens 3 has the direction changed by a spherical lens 3a and goes toward a deflecting reflective face 5a of a polygon mirror 5, and an image is formed in a conjugate position F' of the focus F of the image forming lens 2, and the spread of the beam on the deflecting reflective face 5a is reduced, and the polarizing reflective face of the polygon can be reduced. Consequently, the device is made small-sized, and the scanning efficiency is improved because the polygon is rotated at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scanning device using a semiconductor laser array and an array light source as a light source.
゛Conventional □, semiconductor laser 6-party output t! By arranging multiple 6's and using a so-called semiconductor, -Gon mirror,
If the beams emitted from each light source are expanded too much by improving the deflection reflection of a deflector such as a galvanic mirror, #A
There is an electrical point in which the area of the anti-reflective surface becomes large, and therefore the scanning means becomes large, and the scanning speed cannot be increased.

In order to eliminate the electrical point, 1% Patent Publication No. 1983-69610 provides a collimating lens tube to collimate the light flux t from each light source, and the position of the exit pupil of this collimating lens is placed on the deflection reflection surface. . In this scanning device, in order to arrange an additional optical member between the light S section and the deflector, for example, an anamorphic optical member for correcting the inclination of the rotation axis of the deflector, it is necessary to arrange the light source section and the deflector. If you try to increase the distance between the light source and the deflector, you will inevitably need to increase the focal length of the collimator lens. , with a deflector: It is necessary to increase the outer diameter of a certain polygon mirror. In the former case, the outer diameter of the polygon mirror can be made smaller by making the collimator lens OF number darker.
The ratio of the collimated light flux to the light flux diverging from the light source decreases.

In the latter case, in which the energy use efficiency decreases, if the outer diameter of the polygon is increased, there is no problem with the energy use efficiency.

Not only is it difficult to increase the rotational speed f of the polygons, but it is also difficult to reduce costs.

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks, and to provide a multiple beam scanning device that has high energy utilization efficiency, has a small deflection device, and is capable of continuous scanning.

In the scanning device according to the present invention, a plurality of beam supplying light source section such that the chief rays of the respective O light fluxes supplied are parallel;
A first coupling optical system is provided so that its optical axis is parallel to the principal ray of each light beam of the light source section, and the first coupling optical system is provided between the first coupling optical system and the deflection means. , coaxial with the side optical system -t6A
The first imaging optical system, which has an f@2 imaging optical system, is provided at a position to converge each light beam tube from the light source section and form a part of the light source section. At least in a plane parallel to the deflection scanning plane, the optical system has a focal position of the deflection means of the first optical system and a reflection direction of the deflection means Q-N of the optical system.
The PI is kept at an optically conjugate position with the near-hide position.
3. In this specification, "rF" refers to the above-mentioned deflection scanning surface If which is formed over time according to the sliding movement of the deflector.
means i′.

This means that at least in a plane parallel to the deflection scanning plane, the second imaging optical system is a spherical optical system, and the deflection from the light source is Even in the mountain area (hereinafter referred to as IF, or ``plane perpendicular to the deflection scanning plane'') that includes the optical axis leading to the means and is perpendicular to the deflection scanning plane, the -direction reflection 1f
It is also possible to maintain the optically coexisting relationship between the positions near Iio and
- Or, it may be an anamorphic optical system in which the orthogonal directions have different powers, and in the case of a mountain that is orthogonal to the one-direction scanning direction, it is a problem even if the above-mentioned relation S is not satisfied.

In the scanning apparatus according to the present invention, 1. In order to correct the inclination of the deflection reflecting surface of the deflection means, an edge I is placed on the uA direction reflection circle.
When projecting JII, the second coupling optical system must be an anamorphic optical system. In this case, in the plane perpendicular to the deflection scanning f-plane, the second imaging optical system should have such power that it can converge the light beam from the first WI4 & optical system onto the deflection reflection surface. . The structure of this anamorphic 2nd Keiken Gengaku thread is one spherical optical system and a series/
It can be constructed by a combination of toric optical systems or by a single toric lens.

In a plane parallel to the deflection scanning plane, the imaging position of the light beam from the array light source by the first Ayu image optical system □ coincides with the focal position of the second convergent optical system! If you let it,
The beam incident on the deflection reflection surface of the deflector becomes a parallel light beam; also, the focal position of the second imaging source optical system When the second imaging optical system is located closer to the light source than the imaging position, the □ action of the second imaging optical system increases its role as a field lens, and the beam incident on the deflection reflection surface of the deflector becomes a diverging light flux.

As a result, the shape ri of the beam incident on the deflection reflecting surface is 1#O, and the former case is a linear parallel beam, and the latter case is a linear divergent beam. The present invention will be described in detail below with reference to the drawings. In the embodiments used below, a K112 optical system consisting of a spherical lens and a cylindrical lens will be shown to correct the deflection of the deflector. As the essential S material for the configuration according to the present invention, only a spherical lens may be used, and the cylindrical lens may be omitted. FIG. 1 (AXB) is a diagram showing an embodiment of the scanning device according to the present invention. (A) is a plan view of the entire scanning device.

β) shows a front view of the optical system between the light source section and the deflector. In Section 114(6), 1 is plural i! io
Light emitting section 1a, lbf: semiconductor laser array having, 2
is the chief ray of the luminous flux from the semiconductor laser and its original axis 4
A spherical first imaging lens 3 is provided so that the planes are parallel to each other, and 9 is 1, and 3 is a spherical lens 3a whose generatrix is parallel to the deflection scanning plane and perpendicular to the optical axis 4. A second imaging lens consisting of a cylindrical lens 3b provided, a polygon mirror as a 5Fi deflection means, 6
is a toric rate lens, 7#i is a scanned image, 0, 114, and nine luminous fluxes are emitted from the light emitting parts 1a and lb of the semiconductor array laser beam l.

Each principal light 1i m shown by a dotted line is condensed by the IM* lens 2 and near the second convergence lens 3.
,, m@ passes through the focal point F of the 11th il image V7z2. Therefore, at the position OF, the principal rays of both light beams overlap, and the spatial extent occupied by both light beams is the smallest at 9. The irises of the iris lens are focused in the vicinity of the spherical lens of 3m and produce 9 lights of 5! The direction of the optical path of l[ is changed by the action of the field lens of the spherical lens 31,
Polygon mirror 50 deflection reflection image towards 5m. The focal point r of the first lens and the nearby position F' of the deflection reflection surface.
is the deflection scanning plane 1 shown in port t#A (5)! In the city parallel to K, there is an optically conjugate relationship with respect to the image lens 3 (substantially a spherical lens system 3m). Therefore.

Substantially, on the deflection reflecting surface 5a, a source at the point F is formed by @2 and 3, and a source at point F is formed on the inner reflecting surface 5a. The spread of the beam becomes smaller, the deflection and reflection of the polygon can be made smaller, the apparatus can be made smaller, and the polygon can be rotated at a faster speed, so the scanning efficiency is also improved. The negative O cylindrical lens 5 constituting the second imaging lens 3 has no power in a plane parallel to the unfavorable specular scanning f plane shown in the first position, so it does not affect the scanning beam.

Since the beam incident on the polygon mirror 5 is a diverging light flux, even if the lens thread 6#'i disposed between the polygon mirror 5 and the surface to be scanned is a single lens thread, it is possible to obtain a flat scanned direction with ease. It is possible to scan with a specific spot. The reason for this is to actively take advantage of the Petzval sum of the lens thread 6.9゜This detailed technique can be found in 1987-8754.
Since it is stated in Publication No. 0, I will omit the explanation of Fi here.

In addition, the M image lens 6 is placed within this plane in order to maintain an optically conjugate positional relationship between the polygonal deflection reflection surface 5a and the scanning direction 7 in the mountain area perpendicular to the deflection scanning plane. 69. It is necessary to have power even if the two sides are perpendicular to each other. and each power t
Since it is different, it takes the shape of a toric lens.

Furthermore, in the deflection scanning plane, if the distortion of the si/glutoric lens 6 is made to match the rotational characteristics of the deflector, the scanning surface can be scanned at a constant speed.

I can do it. Therefore, if the original beam enters in the S-divergent state, the deflector and the scanned +kDl! By forming the IK lens system with a single toric lens, it is possible to scan a flat scanned surface at a constant speed and also correct the deflection as shown in Figure 0w41 @. , in the mountains perpendicular to the deflection scanning plane! In this case, the light beam from the first light emitting unit is focused by the first imaging lens system 2 as described above, and then
The negative 7 lindrical lens 3b makes the light beam divergent and enters the sphere-lens 3a41C. The cylindrical concave lens 3b refracts the light beam from the lens thread 2 as if the light beam incident on the spherical lens 3a was emitted from the focal position of the first WI rutting/zoom system 2. As described above, the first
Since the focal position F of the imaging lens system and the position F' near the deflection reflection thi5a of the polygon mirror 5 are maintained in an optically conjugate relationship, the deflection reflection surface 5a of the polygon mirror
S-wei is formed above.

#p, Figure 2 (8)) is a diagram showing the scanning device according to the present invention as well as the O real lA143, Figure 2 (2) is in a plane parallel to the deflection scanning plane, and Figure 2 (03) is in the deflection scanning plane. It shows the optical path in a plane perpendicular to . Figure 2) only shows the optical system between the light source, deflector, and zero. In the second device, each light beam from the light emitting portions 1a, lb of the semiconductor laser array 1 is imaged onto a surface Q by a first focusing optical system 2. One focal point of the second imaging optical system 3D'll (substantially a spherical lens system 3a) is made to coincide with the nine surfaces, so that the second imaging optical system 3 is The passed light flux becomes a parallel beam and heads toward the deflection reflection surface 5a of the deflector.

In addition, as shown in 11W' (a), the optical system shown in FIG. 2 (5) also has a focal point gF of the first imaging lens thread 20,
The deflection/reflection direction 5a (the position F' closest to D) is set to be an optically conjugate position with respect to the second convergence lens system 3.

Therefore, as mentioned above, the spread of the light flux on the deflection reflection #J5a can be made small, and a small deflector can be used.

Since the cylindrical convex lens 3C has no power in the area parallel to the deflection scanning plane, it does not exert any refractive effect on the scanning beam. However, Figure 2 (
B) As shown in K, there is a condensing effect F@ in the plane perpendicular to the deflection scanning plane, and the light flux passing through the cylindrical convex lens 3C and entering the spherical lens 31 is as if it were the first convergent optical fiber 2. The light beam t- is refracted as if it were emitted from a focal point F. Spherical lens 3ari, 1iiiI image lens 20
Since the focal position Ft and the deflection reflection surface 5a are maintained in an optically conjugate positional relationship of approximately ::,.1, the light beam is converged on the deflection reflection surface in a plane orthogonal to the deflection scan l.

Although not shown in FIG. 2(A) (6), there is a scanning imaging lens disposed between the deflector and the surface to be scanned.

In the deflection scanning plane, a parallel beam deflected by a deflector is imaged on the scanned surface to produce a refraction force.

In a plane orthogonal to the deflection scanning plane, it is a nanomirror imaging lens because it has a refractive power i that makes the position F' near the -internal reflection surface and the scanning surface optically conjugate to unity. Soshi-(,
By incorporating the distortion aberration of the anamorphic imaging lens in the @-direction scanning plane into the rotational characteristics of the deflector, the beam spot can be scanned at a constant speed on the scanning plane. Figures 3(A) and 3(B) show a schematic diagram of the 5-year old incense device according to the present invention used in a laser beam printer. FIG. 3 is a developed view in a plane perpendicular to the plane ()'M deflection scan in FIG. 3; Semiconductor array laser that emits a modulated corpse beam
l, a first imaging lens system 2 having an optical axis 14 almost parallel to the principal ray of the i light beams emitted from the array laser; a spherical lens 13a and a positive cylindrical lens 13;
A second imaging optical system 130 consisting of
A) (B) Since it is the same as shown in K, □ here is theory f! 015, omitting A, is a polygon mirror that rotates at a constant speed, and the chief rays (lla, 1lb) from each light emitting unit shown by dotted lines intersect near the deflection reflection surface 15a. Polarized reflective surface 1
The light beam deflected by 5a is focused at a predetermined position on a rotating electrophotographic photosensitive drum 18 by a scanning imaging lens consisting of a meniscus lens 14s whose concave surface faces a polygon mirror 15i14 and a )-rick lens 17. do. The scanning imaging lenses (16, 17) are.

In the - direction scanning plane, it also has an f-- imaging characteristic, so-called I-lens function, and the multiplication beam is deflected by a polygon mirror and moves on the photosensitive drum 18 at a constant speed. On the other hand, in the mountain that is perpendicular to the deflection scanning surface, the light beam r from the light source ll is focused on the deflection reflection surface 15a', and the deflection reflection surface ISa and the photosensitive drum 1B are used as a scanning lens (elephant lens (l" 6, 17), the deflection and reflection ifi 15 a is filled by the original prisoner from the same hometown. Takusazeru 01-1 kangen drum ffdi2
F1 is equipped with a number of members that are essential for the process of forming an electronic photo frame, but this process and arrangement of members is well known at 66 times, so they will not be discussed here. be.

Direction, No. 1-1 No. 21V (as shown, m12 Ayutomoto character thread 3
The silicate/trical lens 3b consists of #I.

3ciU, direction perpendicular to the deflection scanning plane e) Determine whether the refractive power is positive or negative V. This means that the anamonic Kuji member t
ath- position and relationship Meg 9, the light emitted by the thread is placed closer to the light source than the position of moiIB, and 7tJJ! The case of fc has a negative refractive power, and the case of fc, which is placed in one piece, has a positive refractive power of 1.

In addition, in the scanning device related to the unfired qtic, the focal length of the lens system is 2. Light 11 It is uJ to adjust the V distance between the source and the device by one output.
-Hidemeru0 As described above, in the scanning device according to the invention, by simply placing two Ayu-systems with positive lanterns between the one-source source and the deflection-0, the light 61
1ml of main light of multiple beams from s! can be made to intersect near the deflection reflection surface of the deflector, and since the focal length of each imaging system is configured to vary, this is to prevent the deflector from tipping over.

-Even if a line image is formed on a ceramic deflection-reflecting surface, the center positions of the line images of each light beam can be almost matched, so
Even when multiple beams are used, each beam spot on the surface to be scanned is imaged in a good focus state.

[Brief explanation of the drawing]

FIG. 1(B) shows an embodiment of the multiple beam scanning device according to the present invention, and FIG. 2(B) shows another embodiment of the multiple beam scanning device according to the present invention. Fig. 3 device, β) is a diagram showing a multiple beam scanning device according to the present invention to which a laser beam beam printer is applied.l...Semiconductor laser array, la, lb...ray
t, part, 2... first imaging lens system, 3... second imaging lens system s3m... spherical lens, 3b... cylindrical/trical concave lens, 3c... cylindrical convex lens. 4... Optical axis, 5... Polygon mirror, 5a...-
Anti-reflection. Applicant Canon Co., Ltd. 1' Kinuta

Claims (1)

[Scope of Claims] (1) In an apparatus that includes a light source section that supplies each independent maO light beam and scans a surface to be scanned with a plurality of these O light beams, each light beam from the light source section a first #f image optical system arranged so that the principal ray and its light are substantially parallel, and condensing the light flux from the light source to form an image of the light source; Disposed between the image optical system and the image deflection means, and in communication with the deflection scanning surface of the deflection means,
The position of the focal position of the deflection means 1IIo of the first imaging system and the deflection reflection surface of the deflection means is set to a substantially optically conjugate relationship, jlk
(2) The second imaging optical system is an analog optical system, and a light source section and a light source section. Patent 1ill 2. The multiple beam scanning device according to claim 1. (8) *The multiple beam scanning device according to claim 2, in which the second imaging light beam is composed of an i-system line, a spherical beam/z system, and a cylindrical V-n λ system. (The second imaging optical system consists of a single toric lens. The required range @ Section 2 describes the multiple beam scanning device 0 □