JP2003337293A - Optical scanner and light source device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanner capable of correcting (feedback adjustment) the environmental fluctuation of a beam spot array (beam pitch) on a surface to be scanned or the fluctuation of the beam spot array due to aging. <P>SOLUTION: In the optical scanner 20 simultaneously scanning the surface to be scanned 16 in a main scanning direction with a plurality of light beams 21a and 21b emitted from light sources 11a and 11b, a beam spot position on the surface to be scanned is adjusted by varying the position of at least one light beam made to scan the surface 16 by optical path deflecting means (for example, a liquid crystal deflecting element controlled according to an electrical signal) 28a and 28b disposed in the optical path of the light beam. Thus, the beam spot array on the surface to be scanned can be adjusted by driving at a low voltage without making the scanner larger, causing vibration, producing noise or generating heat. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for an optical scanning device (multi-beam scanning device) which simultaneously scans a surface to be scanned with a plurality of light beams emitted from a light source in a main scanning direction, and an optical scanning device thereof. Light source device, and laser printer using the optical scanning device in an optical writing system, digital copying machine,
The present invention relates to an image forming apparatus such as a laser facsimile and a laser plotter.

[0002]

[Prior art]

[Patent Document 1] Japanese Patent Laid-Open No. 2000-227563

[Patent Document 2] Japanese Unexamined Patent Publication No. 10-215351

[Patent Document 3] Japanese Unexamined Patent Publication No. 9-189873

[Patent Document 4] Japanese Patent Laid-Open No. 10-282531

[Patent Document 5] Japanese Patent Laid-Open No. 2000-3110

[Patent Document 6] Japanese Patent Laid-Open No. 2000-47214

[Patent Document 7] Japanese Patent Laid-Open No. 63-240533

[Patent Document 8] Japanese Unexamined Patent Publication No. 8-313941

[Patent Document 9] JP-A-9-325288

[Patent Document 10] Japanese Patent Laid-Open No. 10-62705

In an optical scanning device used in an optical writing system of an image forming apparatus, a means for improving the recording speed is as follows.
There is a method of increasing the rotation speed of the polygon mirror that is the deflecting means. However, with this method, the durability and noise of the motor,
Vibration and the modulation speed of the laser are problematic and limited. Therefore, an optical scanning device (multi-beam scanning device) has been proposed which scans a plurality of light beams at a time to record a plurality of lines at the same time. As a method of a multi-beam light source device used as a light source means of this optical scanning device (multi-beam scanning device) and emitting a plurality of laser beams, for example, a multi-beam semiconductor having a plurality of light emitting points (light emitting channels) in one package Although there is a method of using a laser (for example, a semiconductor laser array), it is difficult to increase the number of channels in the manufacturing process of the semiconductor laser array, and it is possible to eliminate the influence of thermal / electrical crosstalk. It is currently an expensive light source means because it is difficult and it is difficult to shorten the wavelength.

On the other hand, the single-beam semiconductor laser is still relatively easy to shorten the wavelength, can be manufactured at low cost, and is widely used in various industrial fields. Many proposals have been made in the past regarding a light source device and a multi-beam scanning device that combine a plurality of laser beams using a beam combining means using this single-beam semiconductor laser (or the above-mentioned multi-beam semiconductor laser) as a light source. However, compared with the method of using the semiconductor laser array as the light source means, in the case of the method of synthesizing a plurality of laser beams using the beam synthesizing means, the beam spot array ( The problem that the beam pitch; the scanning line interval) fluctuates easily occurs.

A representative example of the prior art relating to a method for solving this problem is shown below. (1) [Patent Document 1] "Multi-beam scanning optical device" described in Japanese Patent Laid-Open No. 2000-227563 In a multi-beam scanning optical device that combines light beams emitted from a plurality of light sources using a beam combining prism, The beam spot position on the surface to be scanned can be adjusted by adjusting the emission direction of the light beam by shifting the beam combining prism along the optical path and adjusting the tilt in the main scanning section or the sub-scanning section. Have been described. (2) [Patent Document 2] "Light beam scanning device" described in Japanese Patent Application Laid-Open No. 10-215351 In a light beam scanning device for combining light beams emitted from a plurality of light sources using a beam combining prism, a polygon mirror It is described that the beam spot position on the surface to be scanned is adjusted by adjusting the emission direction of the light beam by shifting the cylindrical lens for forming a line image on the reflecting surface in the sub-scanning direction. ing. (3) [Patent Document 3] "Multi-beam scanning method and multi-beam scanning device" described in Japanese Patent Application Laid-Open No. 9-189873 A multi-beam scanning device for combining light beams emitted from a plurality of light sources using a half mirror In, by adjusting the inclination of the galvanometer mirror and the inclination of the light source device provided in the optical path, by adjusting the emission direction of the light beam,
It is described that the beam spot position on the surface to be scanned is adjusted. (4) [Patent Document 4] "Optical Deflector" described in Japanese Patent Application Laid-Open No. 10-282531 A laser beam is deflected by utilizing a change in the refractive index of an electro-optical material (such as lithium niobate) having an electro-optical effect. It is described to do. (5) [Patent Document 5] "Image forming apparatus and method for controlling image forming apparatus" described in Japanese Patent Application Laid-Open No. 2000-3110. An invention in which a scanning position on a surface to be scanned is adjusted by an optical path deflecting element (liquid crystal element). Yes, the scanning line pitch unevenness due to the uneven rotation of the photosensitive drum is corrected. Further, it has a detection means for detecting the peripheral speed of the photosensitive drum. (6) [Patent Document 6] "Optical path changing device and image forming apparatus using the same" described in Japanese Patent Laid-Open No. 2000-47214, and an optical path deflecting element having a plurality of liquid crystal layers, and image forming using the same. The present invention relates to an apparatus, and an object of the present invention is to correct scanning line pitch unevenness caused by rotation unevenness of a photosensitive drum, as in the above (5).

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention (1)-
In many of the existing inventions such as (3), the beam spot arrangement on the surface to be scanned is adjusted by deflecting the optical path of the light beam using a mechanical mechanism. However, in the case of an adjusting mechanism having a mechanical mechanism, reliability is reduced (shorter life) due to an increase in the number of parts, the unit is enlarged, hysteresis is generated during control due to backlash, vibration /
There is a possibility that various problems such as noise / heat generation may occur.

Further, a method of utilizing the change in the refractive index of the prism by the electro-optical effect, such as the above-mentioned prior art (4), and a method of deflecting a light beam by diffraction using an acousto-optic element have been proposed. However, since a high driving voltage is required, the handling is complicated, and problems such as heat generation occur, which is not a practical method. On the other hand, in the above-mentioned prior arts (5) and (6), in the image forming apparatus, the unevenness of the scanning line pitch caused by the uneven rotation of the photosensitive drums is corrected (the superposition of the image information between the photosensitive drums in the tandem optical scanning device). A liquid crystal element is used as an optical path deflecting element in order to improve accuracy.

The present invention has been made in view of the above circumstances, and in an optical scanning device that simultaneously scans a surface to be scanned with a plurality of light beams emitted from a light source in the main scanning direction, the surface of the surface to be scanned is scanned. An object of the present invention is to provide an optical scanning device capable of correcting (feedback adjustment) the environmental change of the beam spot array (beam pitch) or the temporal change of the beam spot array. It is another object of the present invention to provide a small light source device in an optical scanning device capable of adjusting the beam spot arrangement on the surface to be scanned. A further object of the present invention is to provide an image forming apparatus including the above optical scanning device and capable of obtaining a high quality output image.

[0009]

In order to achieve the above object, the invention according to claim 1 provides an optical scanning device capable of adjusting a beam spot arrangement on a surface to be scanned. , "In an optical scanning device that simultaneously scans a surface to be scanned in the main scanning direction with a plurality of light beams emitted from a light source, an optical path deflecting unit disposed in the optical path of the light beam scans the surface to be scanned. The position of at least one light beam is changed. "

The invention according to claim 2 shows a specific example of the optical path deflecting means in the optical scanning device according to claim 1, wherein the optical path deflecting means comprises a liquid crystal element controllable by an electric signal. A liquid crystal deflecting element is used, and the position of at least one light beam scanned on the surface to be scanned is changed by the liquid crystal deflecting element. " The invention according to claim 3 is the optical scanning device according to claim 2, wherein "the liquid crystal deflecting element is capable of independently deflecting a light beam in two directions orthogonal to each other".

According to a fourth aspect of the present invention, in the optical scanning device according to the second aspect, the number of components is reduced and the positioning accuracy is improved. It has a plurality of effective areas that can be modulated. ” According to a fifth aspect of the invention, in the optical scanning device according to the second aspect, it is possible to easily adjust the beam characteristics of the emitted light beam. And a coupling lens for coupling the laser light emitted from the semiconductor laser. ”

Further, the invention according to claim 6 is, in the optical scanning device according to claim 2 or 4, intended to expand the degree of freedom of the arrangement of the light sources, and is to say that "light beams emitted from a plurality of different light sources are , Using beam synthesizing means ”. According to a seventh aspect of the present invention, in the optical scanning device according to the sixth aspect, the combining error of the beam combining means is corrected, wherein "the light source is at least a semiconductor laser serving as a light emitting point, and the semiconductor. A coupling lens for coupling laser light emitted from a laser, which corrects a synthesis error of the beam synthesizing means when the semiconductor laser and the corresponding coupling lens are assembled (position adjustment / fixation). It can be assembled as a product.

According to an eighth aspect of the present invention, in the optical scanning device according to the second aspect, the size of the effective area of the liquid crystal deflecting element is set to a necessary minimum, and "Aperture having an opening for beam shaping is used. The member is arranged on the upstream side (light source side) of the liquid crystal deflecting element in the optical path of the light beam. " The invention according to claim 9 is the invention according to claim 8.
The optical scanning device described above is intended to improve the positioning accuracy of the aperture and the effective area of the liquid crystal deflecting element, and is characterized in that "the aperture for beam shaping is formed on the incident surface or the emitting surface of the liquid crystal deflecting element". I am trying.

The invention according to claim 10 is the optical scanning device according to any one of claims 2 to 9, wherein a plurality of light beams emitted from a light source are simultaneously emitted onto a surface to be scanned. In an optical scanning device that scans as a light spot, it is intended to suppress deterioration of the beam spot array due to temperature change / time change. Means and a drive means for driving / controlling the liquid crystal deflecting element based on the detection result, and the position of at least one light spot is variable. ”

The invention according to claim 11 provides a small light source device in an optical scanning device capable of adjusting a beam spot arrangement on a surface to be scanned, and is used in the optical scanning device according to claim 1. A light source device for emitting a plurality of light beams, comprising a plurality of optical path deflecting means for independently deflecting the respective light beams corresponding to the light beams emitted from the plurality of light sources. The optical path deflecting means has an integrated structure. "

According to a twelfth aspect of the present invention, in the light source device according to the eleventh aspect, the sensitivity of beam spot position adjustment adapted to the characteristics of the scanning optical system is obtained. It is a transmissive optical element disposed in. According to a thirteenth aspect of the present invention, in the light source device according to the eleventh aspect, the sensitivity of beam spot position adjustment adapted to the characteristics of the scanning optical system is obtained. It is characterized in that it is a reflection type optical element provided.

According to a fourteenth aspect of the present invention, in the light source device according to the twelfth or thirteenth aspect, a high resolution (finely adjustable) adjusting mechanism is realized. The element is driven by driving means using a piezoelectric element. " Also,
According to a fifteenth aspect of the present invention, in the light source device according to the twelfth or thirteenth aspect, a desired output (displacement of the optical element or each displacement) is reliably achieved with respect to the input signal. The element or the reflection-type optical element is driven by a driving means using a pulse motor that rotates a predetermined angle by an input pulse signal or a pulse motor that moves straight by a predetermined distance by an input pulse signal. " .

According to a sixteenth aspect of the present invention, in the light source device according to the eleventh aspect, there is provided a light source device capable of adjusting the beam spot position without moving parts and with low power consumption. Is a liquid crystal element (liquid crystal deflecting element) driven by an electric signal. ” Further, the invention according to claim 17 is,
In the light source device according to any one of the above, for facilitating initial adjustment of the beam spot array,
"A plurality of light sources are arranged in a line in the main scanning direction, a first light source unit that integrally holds these, a second light source unit configured similarly to the first light source unit, and the first And a beam synthesizing means for closely emitting the light beams emitted from the second light source portion. ”

The invention of claim 18 relates to claims 11 to 1.
In the light source device according to any one of 7, the beam characteristics (collimation rate,
This is for facilitating adjustment in the optical axis direction) and is characterized in that "the plurality of light sources are composed of a plurality of semiconductor lasers and coupling lenses corresponding thereto". Further, the invention according to claim 19 is,
In the light source device according to any one of the above, it is intended to narrow the effective area in the optical path deflecting means, and "Aperture member having an opening for light beam shaping,
It is provided on the upstream side (light source side) of the optical path deflecting means ”.

The invention of claim 20 relates to claims 11 to 1.
9. A light scanning device comprising the light source device according to any one of 9 to scan a plurality of light beams emitted from a light source as a light spot on a surface to be scanned, the beam according to temperature change / time change. In order to suppress the deterioration of the spot arrangement, "a detecting means for detecting the arrangement of a plurality of light spots on the surface to be scanned, and a driving means for driving / controlling the optical path deflecting means based on the detection result. It is characterized by having. The invention according to claim 21 is the optical scanning device according to claim 20, wherein a plurality of light beams emitted from the light source are deflected and reflected by a deflector,
In an optical scanning device that scans a surface to be scanned as a light spot by a scanning imaging optical system, a synchronization signal for setting a modulation start timing is detected independently for each light beam. The plurality of light beams (the chief rays of the light beams) incident on the vessel are not parallel to each other in the main scanning section. "

The invention according to claim 22 is the optical scanning device according to claim 1, which provides an optical scanning device capable of adjusting a beam spot position on a surface to be scanned, which comprises "a plurality of light source means. A light source device, a beam combining means for combining a plurality of light beams emitted from the light source device, a deflector for deflecting the plurality of light beams combined by the beam combining means, and a deflector deflected by the deflector. In an optical scanning device including a scanning unit that guides a plurality of light beams onto a surface to be scanned, an optical path deflecting unit that deflects an optical path of the light beams in order to control the position of the light beam on the surface to be scanned, It is provided between the light source means and the beam combining means. " According to a twenty-third aspect of the present invention, in the optical scanning device of the twenty-second aspect, "the optical path deflecting means is provided with a transmissive optical element eccentrically provided".

By the way, in the optical scanning device according to the twenty-second aspect, the liquid crystal element is used as the optical path deflecting means to perform optical path deflection, so that adjustment (correction) of the beam spot position on the surface to be scanned can be easily realized. You can Further, it is possible to correct a temporal change in beam spot position due to a temperature change or the like. Furthermore, there are advantages such as low loss of light quantity and low driving power.

On the other hand, liquid crystal elements generally have a drawback that ghost light is likely to be generated due to diffraction. Here, the liquid crystal element can be roughly classified into the following two types. (1) A method in which an applied voltage is applied to a plurality of electrodes to generate a refractive index distribution and the incident light is deflected by a prism effect. (2) A method in which a stripe pattern that functions as a diffraction grating is generated by applying an applied voltage to a plurality of electrodes, and incident light is deflected by the diffraction effect.

In any case, since the plurality of electrodes form an electrode pattern arranged at substantially equal intervals, diffracted light corresponding to the electrode pitch is generally generated. Of the diffracted light generated by the electrodes, the 0th-order light is deflected as write data,
± 1st order light, ± 2nd order light, ± 3rd order light, etc. are unnecessary ghost lights. When such ghost light reaches the surface to be scanned, a ghost image may be generated on the image, which may cause image deterioration.

Therefore, the invention according to claim 24 is to eliminate the ghost light generated in the liquid crystal element when the liquid crystal element is used for the optical path deflecting means. "In the optical scanning device according to claim 22, The optical path deflecting means is a liquid crystal element (liquid crystal deflecting element) that can be controlled by an electric signal, and a ghost light removing means (slit aperture) for removing ghost light generated in the liquid crystal element is provided with a liquid crystal element and a deflector. "Prepared in between". According to a twenty-fifth aspect of the invention, in the optical scanning device according to the twenty-fourth aspect, the ghost light is effectively removed, and "in the optical path on the upstream side (light source means side) of the optical path deflecting means". It is equipped with an aperture stop (aperture) for shaping a light beam, and satisfies the following relational expression ”. L> (1/2) × tan θ × (b + Δ) {b: Total width (diameter) of light beam deflected by liquid crystal element Δ: Total width of slit opening L: Distance between liquid crystal element and slit opening 2θ: In liquid crystal element Of the ghost light generated, + 1st-order light and −
Angle between primary lights}

Further, the invention according to claim 26 facilitates the replacement of parts when the light source means (semiconductor laser or the like) is deteriorated, and "the light according to any one of claims 22 to 25 is provided. An optical scanning device having a scanning device housed in an optical housing, wherein the light source device is fixed or held on a side wall of the optical housing, and the optical path deflecting means and the beam synthesizing means are fixed on a common holding portion inside the optical housing. Or be retained ”.

Next, the invention according to claim 27 provides an image forming apparatus capable of achieving high speed image forming speed, high density, high quality, and reduction of environmental load, and capable of obtaining a high quality output image. What is provided is "Claims 1-10, 20-26.
And a developing means for developing an electrostatic latent image with toner, and a developing means for developing the electrostatic latent image with toner. And a transfer unit that transfers the imaged toner image to a recording medium ”.

The invention according to claim 28 provides an image forming apparatus capable of achieving high-speed image forming speed, high density, high quality, and reduction of environmental load, and capable of obtaining a high quality output image. The image forming apparatus according to claim 27 is characterized in that the operator drives / controls the optical path deflecting element based on the output image on the recording medium.

The invention according to claim 29 is to provide an image forming apparatus compatible with the tandem system.
Alternatively, the image forming apparatus described in Item 28 has a plurality of photosensitive means serving as a surface to be scanned ”. The invention according to claim 30 provides an image forming apparatus compatible with a divided scanning method.
8. The image forming apparatus according to item 8, wherein a plurality of the optical scanning devices are provided, and the plurality of optical scanning devices are arranged in series in the main scanning direction with respect to one photosensitive unit. ” Furthermore, the invention according to claim 31 is characterized in that "in the image forming apparatus according to any one of claims 27 to 30, the pixel density can be switched."

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] First, as the first embodiment of the present invention, the configuration of the invention according to claims 1 to 10,
The operation and action will be described in detail based on the illustrated embodiment. In the following description of the embodiments, the X direction is along the optical path (optical axis), the Y direction is the main scanning (corresponding) direction,
The Z direction is the sub-scanning (corresponding) direction. Further, the "main scanning direction" and "sub-scanning direction" usually mean the direction in which the beam spot is scanned on the surface to be scanned and the direction orthogonal thereto,
In the present embodiment, the directions corresponding to the main scanning direction (of the surface to be scanned) and the sub-scanning direction (in a broad sense) at each position of the optical path are called the “main scanning direction” and the “sub-scanning direction”, respectively. .

(Embodiment 1-1) FIG. 1 is a view showing an embodiment of the present invention and is a perspective view showing an optical arrangement of an optical scanning device. In FIG. 1, the “light source device 18” is composed of at least “two sets of semiconductor lasers 11a and 11b and coupling lenses 12a and 12b”, but it is not limited to such a structure. The semiconductor lasers 11a and 11b may be single beam semiconductor lasers having a single light emitting point or multi-beam semiconductor lasers (semiconductor laser array) having a plurality of light emitting points. Laser light emitted from the semiconductor lasers 11a and 11b is coupled by coupling lenses 12a and 12b, and two light beams (laser beams) 2
1a and 21b.

Two light beams 2 emitted from the light source device 18
1a and 21b are imaged as line images (imaged in the sub-scanning direction and long in the main scanning direction) on the deflective reflection surface of the polygon mirror 14 which is a deflector by the action of the cylindrical lens 13, and then two sheets are formed. A scanning optical system 15 including scanning lenses 15a and 15b and a folding mirror 15c scans a surface to be scanned (for example, a photosensitive drum) 16 as a beam spot. The device 20 that scans the plurality of light beams emitted from the light source device 18 as a beam spot on the surface 16 to be scanned will be referred to as an "optical scanning device (or a multi-beam scanning device)".

When this optical scanning device 20 is used as an optical writing device of an image forming apparatus, a light beam is modulated in accordance with output image data, and an electric signal (synchronization signal) for the modulation start timing Is obtained when the light beam is incident on the synchronization detection plate 19. Here, FIG. 2 shows an optical arrangement and an optical path in the main scanning section (section parallel to the optical axis and the main scanning direction).
In the vicinity of the deflecting / reflecting surface of the polygon mirror 14 intersect at "angle θ". This makes it possible to suppress the occurrence of deviations in optical characteristics (field curvature, magnification error, etc.) between the two beams.

Further, as shown in FIG. 3, the two beam spots BS1 and BS2 formed by the two light beams 21a and 21b on the surface 16 to be scanned have a predetermined interval (beam pitch: PY) in the main scanning direction. They are arranged, but depending on the scanning density, a predetermined interval (beam pitch: P
Z) is required to be maintained. To set this beam pitch, as shown in FIG.
Two light beams 21a and 21 emitted from a and 11b
The angle formed by b (the emission angle of the two light beams projected on the sub-scan section) φ may be set.

In FIG. 1, the coupling lens 12
In the optical path between the a and 12b and the cylindrical lens 13, a liquid crystal deflecting element 28 including two liquid crystal elements 28a and 28b is disposed as an optical path deflecting means, and in the optical paths of the two light beams 21a and 21b. By driving / controlling (modulating) the liquid crystal elements 28a and 28b of the arranged liquid crystal deflecting element 28 with electric signals, two light beams 21a and 21b are provided.
The optical axis (direction of the light beam) can be independently deflected. This makes it possible to set the angle φ to a desired value (claims 1 and 2). The deflection of the light beam may be performed on both of the two light beams 21a and 21b, or may be performed on only one of the light beams.

Conventionally, as an optical path deflecting means for deflecting the optical path of a light beam, a mechanical method (moving a mirror, a prism, etc. arranged in the optical path), a method using an electro-optical element (electro-optical element material) The optical path is deflected using the change in the refractive index of the prism), the method that uses an acousto-optic element (a diffraction grating is generated in the piezoelectric body by ultrasonic waves to deflect the optical path), etc. Although they have been proposed and put into practical use, all of them have problems due to the reasons such as an increase in size of the device, generation of vibration, noise, heat, and difficulty in low voltage driving.

However, by using the liquid crystal deflecting element 28 of this embodiment as the optical path deflecting means for deflecting the light beam, it becomes possible to downsize the device, suppress the occurrence of vibration, etc., and drive it at a low voltage. .

Here, FIGS. 5A and 5B show an example of the configuration and operation of the liquid crystal deflecting element 28. In FIG. 5A, the liquid crystal element that constitutes the liquid crystal deflecting element 28 includes two transparent glass substrates 28-1 on which a transparent electrode 28-2 and an alignment film 28-3 are formed, a spacer 28-4, And liquid crystal 28
-5, two glass substrates 28-1 are arranged with a spacer 28-4 sandwiched so that the alignment films 28-3 face each other, and a liquid crystal is placed in the space between the two glass substrates 28-1. 28
-5 is filled. Transparent electrode 2 of this liquid crystal element
By connecting a drive control system 28-6 to 8-2 and inputting a rectangular wave or a sine wave as a drive voltage, the drive control system 28-6 shown in FIG.
The light beam can be deflected, as shown in. Further, the deflection angle can be adjusted by changing the width (duty) or the amplitude of the rectangular wave or the sine wave.

If it is desired to increase the response speed of light beam deflection in order to deal with uneven rotation of the photosensitive drum,
A liquid crystal element composed of a plurality of liquid crystal layers may be used as the liquid crystal deflecting element 28, and the liquid crystal layer may be a single layer if the response speed does not need to be increased as much as above.

On the other hand, the interval PY between the beam spots in the main scanning direction on the surface 16 to be scanned is given by PY = FY × θ, where FY is the focal length of the scanning optical system in the main scanning direction. Therefore, the liquid crystal deflecting element 28 is used to deflect both or one of the two light beams, and the angle formed by the two light beams is changed by "the angle Δθ in the main scanning cross section". “Angle θ” of “θ + Δ
θ ”. This makes it possible to set the interval PY in the main scanning direction to a desired value. That is, by independently deflecting at least one of the light beams in two directions (main scanning direction and sub-scanning direction), it becomes possible to arbitrarily set (adjust) the beam spot arrangement on the scanned surface 16. Claim 3). In this case, the liquid crystal deflecting element 28 may be integrated or may be integrated (two pieces are stacked).

In FIG. 1, the liquid crystal elements 28a and 28b constituting the liquid crystal deflecting element 28 are individually provided for the two light beams. On the other hand, as shown in FIG. 6 described later, the liquid crystal deflecting element 28 formed of a single liquid crystal element is divided into a plurality of (two in the case of FIG. 6) regions (effective areas), and each effective area is independent of each other. It can be modifiable (claim 4). As a result, the number of parts can be reduced, the positioning accuracy can be improved, and the wiring for inputting an electrical signal can be simplified.

Here, a supplementary description will be given of an example of the configuration and operation of the "liquid crystal deflecting element" applicable to the present invention. It is known that the liquid crystal deflecting element is driven by an electric signal and the liquid crystal deflecting element is driven by a magnetic signal, but in the following description, an example of driving by an electric signal will be described. . The liquid crystal deflecting element that deflects a light beam by driving with an electric signal is roughly classified into two types: one that “changes the refractive index” by an electric signal and one that “causes a diffractive action” by an electric signal. To be

First, a liquid crystal deflecting element utilizing the change in refractive index will be described. This type is described in, for example, [Patent Document 7] Japanese Patent Laid-Open No. 63-240533. FIG. 32 shows an example. FIG. 32 (b)
In the above, the liquid crystal 1 is a “nematic liquid crystal having a positive dielectric anisotropy”, and is sealed in a thin layer between the pair of transparent alignment films 2A and 2B held by the spacer 3 in a predetermined gap. The liquid crystal molecules indicated by reference numeral 1A have a "long shape in the molecular axis direction". The alignment film 2A is subjected to alignment treatment so that the molecular axes of the liquid crystal molecules 1A are orthogonal to the alignment film surface.
In B, the alignment treatment is performed so that the molecular axis of the liquid crystal molecule 1A is parallel to the alignment film surface.

A transparent electric resistance film 4 made of ZnO or the like is formed outside the alignment film 2A. The transparent electric resistance film 4, the alignment films 2A and 2B, and the liquid crystal 1 are sandwiched by a pair of transparent glass substrates 5A and 5B as shown in FIG. 32 (b). I is formed on the surface of the glass substrate 5B on the side of the alignment film 2B.
A transparent electrode film 6 made of TO or the like is formed on one surface.
On the other hand, as shown in FIG.
Electrodes 7A and 7B having a pattern as shown in (a) are formed, and these electrodes 7A and 7B are in contact with the electric resistance film 4 as shown in (b). The electrodes 7A, 7B are formed as transparent electrodes made of ITO or the like when "they are in the light flux transmission area", but the electrodes 7A, 7B are not in the light flux transmission area (the electrodes 7A, 7B are It is also possible to form an opaque electrode by using a metal thin film or the like (if the light flux is not blocked). In the example of FIG. 32, the electrodes 7A and 7B are formed as transparent electrodes.

In the state of FIG. 32B, the electrode film 6 and the electrode 7B are grounded, and the electrodes 7A and 7B shown in FIG.
When a voltage V is applied between the terminals A and B of the electric resistance film 4
Potential linearly decreases from the electrode 7A side to the electrode 7B side. Therefore, between the electric resistance film 4 and the transparent electrode film 6, "the electric field linearly decreasing from the upper side to the lower side in FIG. 32 (b) (the direction is the left-right direction in the figure)". Works. This electric field acts on the liquid crystal 1 to rotate the liquid crystal molecule 1A "in such a manner that its molecular axis is parallel to the electric field".
The rotation angle of the liquid crystal molecule 1A is "linearly proportional to the strength of the electric field."
Therefore, when the electric field acts, the molecular axis of the liquid crystal molecule 1A is closer to the direction of the electric field (left and right direction in the figure) on the electrode 7A side, but the electric field is substantially 0 on the electrode 7B side. The molecular axis of the liquid crystal molecule 1A remains almost parallel to the electrode film 6.

The dielectric constant of the liquid crystal molecule 1A is large in the direction parallel to the molecular axis and small in the direction orthogonal to the molecular axis. Therefore, the refractive index becomes larger in the direction parallel to the molecular axis. When the above-mentioned “distribution of the orientation of the molecular axis of the liquid crystal molecule 1A” is generated by the action of the electric field, the “refractive index” in the liquid crystal 1 is high on the side of the electrode 7A whose molecular axis is substantially parallel to the electric field, It becomes lower on the side of the electrode 7B, and linearly decreases from the side of the electrode 7A to the side of the electrode 7B as shown in FIG. 32 (c). Therefore, when a light beam is made incident on the liquid crystal deflecting element having such a refractive index distribution from the right side of FIG. 32 (b) and is transmitted through the liquid crystal deflecting element, the transmitted light beam has a refractive index distribution due to the action of the refractive index distribution. High side (Fig. 32)
It is deflected upward in (b). The electrode to be grounded is electrode 7B
To 7A and the direction of the voltage applied between terminals A and B is reversed from the above, the refractive index distribution decreases from the electrode 7B side to the electrode 7A side, contrary to the case of FIG. And the transmitted light flux can be deflected downward in FIG.

The above is the principle of light beam deflection by the liquid crystal deflecting element utilizing the change in refractive index. The deflection amount, that is, the "deflection angle", which is the degree of deflection, is saturated with a value peculiar to the liquid crystal deflecting element, and when it is saturated, a larger deflection angle does not occur. A "DC voltage" may be used as an electric signal for driving the liquid crystal deflecting element, but from the viewpoint of the life of the liquid crystal deflecting element,
The electric signal is preferably a signal that is modulated in a pulse shape or a sine wave shape and has an average voltage in the vicinity of 0V. The deflection angle can be changed by increasing or decreasing the potential difference V between the terminals A and B, but when the pulse signal is used as the drive signal, it can also be changed by changing the "pulse duty ratio". be able to. In the case of the liquid crystal deflecting element as shown in FIG. 1, if the distance between the electrodes 7A and 7B is larger than the light beam diameter, no diffracted light is generated.

FIG. 33 shows another example of the "liquid crystal deflecting element of the type in which the refractive index is changed by an electric signal". To avoid complications, see Figure 3 for items that are not likely to be confused.
The same reference numerals as in 2 were used. This element is a modification of the element of FIG. 32, and the difference from the element of FIG. 32 is that the transparent electric resistance film is divided into three parts 4A, 4B, 4C on the glass substrate 5A side, and the transparent electrode is Patterning is performed as shown in FIG. 33A, and the transparent electrode 7A is formed on the electric resistance film 4A.
1 and 7B1 correspond to each other, and the transparent electrode 7A2 is provided on the electric resistance film 4B.
And 7B2 correspond to each other, and the transparent electrodes 7A3 and 7B3 correspond to the electric resistance film 4C. When a drive signal is applied between the terminals A and B, a refractive index distribution as shown in FIG. 33 (c) is obtained. In this case, the voltage applied to terminals A and B: V
Since the change rate of the electric field with respect to is large, a "larger refractive index gradient" can be obtained and a larger deflection angle (deflection amount) can be obtained as compared with the element of FIG.

In the case of the liquid crystal deflecting element of the type shown in FIG. 33, the number of combinations of the electric resistance film and a pair of electrodes (for example, the electric resistance film 4A and the electrodes 7A1 and 7A2) combined therewith (3 in the above example). As the angle becomes larger, the deflection angle can be made larger, but the period of the periodic structure of the above combination in the light transmitting region becomes smaller, and diffracted light is generated.

FIG. 34 shows still another example of the liquid crystal deflecting element. This liquid crystal deflecting element is "an element that causes a diffracting action by an electric signal". This type of liquid crystal deflecting element is described in detail, for example, in [Patent Document 8] JP-A-8-313941. In order to avoid complication in FIG. 34 as well, for items that are not likely to be confused,
The same reference numerals as in FIG. 32 are used.

In FIG. 34 (a), the liquid crystal 1 is, for example, "a nematic liquid crystal having a negative dielectric anisotropy in which the dielectric constant of the liquid crystal molecule 1A in the molecular axis direction is smaller than the dielectric constant in the direction orthogonal to the molecular axis". Thus, a thin layer is sealed between the pair of transparent alignment films 2A and 2B which are kept at a predetermined gap by the spacer 3. The alignment films 2A and 2B are sandwiched between a glass substrate 5A having a transparent electrode 6A and a glass substrate 5B having a transparent electrode 6B. The transparent electrodes 6A and 6B are formed of ITO or the like in a thin film shape, and are uniformly formed in a predetermined shape (for example, a rectangular shape) on the surfaces of the glass substrates 5A and 5B, respectively. The alignment films 2A and 2B perform alignment with respect to the liquid crystal 1 so that the molecular axis directions of the liquid crystal molecules 1A are orthogonal to the drawing.

In such a situation, "a direct current or a low frequency voltage of about 300 Hz or less" is applied between the transparent electrodes 6A and 6B.
Is applied, a diffraction grating pattern is formed in the liquid crystal 1 with the grating arrangement direction being the vertical direction of the figure (the direction orthogonal to the “alignment direction”) (paragraph “00 of Patent Document 8”).
54 "). FIG. 34B shows the refractive index distribution in the diffraction grating pattern thus formed. When the light flux is incident on the liquid crystal deflecting element in this state, the transmitted light is diffracted by the diffraction grating pattern (in the vertical direction of FIG. 34 (a)). When the voltage value of the low frequency voltage is changed,
The grating pitch of the formed diffraction grating pattern changes, and the diffraction angle changes (paragraph “005 of Patent Document 8”).
7 "). Therefore, for example, focusing on the “first-order light of diffraction”, by adjusting the deflection angle of the first-order light, the luminous flux is desired in a predetermined direction (in the above-described case, the vertical direction of FIG. 34A). It can be deflected at a deflection angle of.

Further, the transparent electrode 6 of the liquid crystal deflecting element of FIG.
When the voltage applied between A and 6B is a high frequency voltage, a diffraction grating pattern in a direction orthogonal to the alignment direction appears in the liquid crystal 1 and "diffracted light in a direction orthogonal to the drawing" of FIG. 34 (a) can be obtained. it can. In this case, the diffraction angle can be changed by increasing or decreasing the “envelope voltage” of the high frequency voltage applied to the liquid crystal (paragraph “00” of [Patent Document 8]).
60 ").

The "liquid crystal deflecting element of the type in which a light beam is deflected by an electric signal" known in the related art has been briefly described above. In the present invention, as one of the optical path deflecting means, these known liquid crystal deflecting elements (not limited to those driven by electric signals but not described above, those driven by magnetic signals may be used) are used. The scanning position of the light spot is adjusted by deflecting the light beam.

(Embodiment 1-2) Next, FIG. 6 is a view showing another embodiment of the present invention, and is a perspective view showing only the optical system in front of the deflector of the optical scanning device. The optical system layout after the deflector 14 is the same as that shown in FIG. In this embodiment, the "light source device 18" is composed of at least "two sets of semiconductor lasers 11a and 11b and coupling lenses 12a and 12b" as in Embodiment 1-1. It is not limited to. The semiconductor lasers 11a and 11b may be single beam semiconductor lasers having a single light emitting point or multi-beam semiconductor lasers (semiconductor laser array) having a plurality of light emitting points.

The laser light emitted from the semiconductor lasers 11a and 11b is coupled by the coupling lenses 12a and 12b, and two light beams (laser beams) are provided.
21a and 21b. Two light beams 21a and 21b
Are combined in close proximity to each other by a beam combining prism 17 serving as a beam combining means. By adopting such a configuration, it is possible to expand the degree of freedom in the arrangement of the light source and reduce the angle θ at which the two light beams intersect in the vicinity of the deflecting / reflecting surface of the polygon mirror 14 in the main scanning cross section.
The effect that the control board for driving / controlling the two semiconductor lasers can be integrated can be obtained (claim 6).

Further, the light source is changed to "semiconductor lasers 11a, 1
1b and the coupling lenses 12a and 12b ", it becomes possible to easily obtain the characteristics of the light beam (collimating property and optical axis direction) according to the characteristics of the optical system thereafter (claim 5). . For example, as shown in FIG. 7, the semiconductor laser 11 fixed to the holding member 22 by press fitting.
While observing the beam characteristics of the light beam 21 emitted from the laser beam and coupled by the coupling lens 12,
After adjusting the position of the coupling lens 12 with respect to the semiconductor laser 11, the coupling lens 12 may be fixed to the holding member 22 with an ultraviolet curable adhesive or the like.

Alternatively, as shown in FIG. 8, the lens cell 23 having the coupling lens 12 and having the male screw portion is screwed into the female screw portion of the holder member 24 to adjust the collimation rate in the X direction (left and right direction in the figure). ) And the semiconductor laser 11 held by the base member 25.
Relative positions in the Y direction and the Z direction (vertical direction in the drawing and a direction perpendicular to the paper surface; adjustment of the emission direction of the light beam) can be performed. Such adjustment of the relative positional relationship between the semiconductor laser and the coupling lens is generally called “optical axis / collimation adjustment” in many cases.

By the way, as shown in FIG. 9, the two light beams 21a and 21b are combined due to the influence of processing errors of the beam combining means (the beam combining prism 17 in this embodiment) and component errors (internal refractive index, etc.). Accuracy error (optical axis deviation: e)
May occur. Due to this optical axis deviation e, the distance between the beam spots on the surface 16 to be scanned may have an error with respect to a desired value.

For example, when the optical axis deviation e is generated in the sub-scanning direction, the interval between the beam spots on the surface to be scanned 16 in the sub-scanning direction: PZ is expressed by the following equation.
Only PZ will cause an error. ΔPZ = mZ × fcol × tan (e) fcol: Focal length of coupling lens mZ: Sub-scanning lateral magnification of the entire scanning optical system (optical system between the light source and the surface to be scanned) where mZ = 10 times , Fcol = 15 [mm] and e = 10 minutes = 2.9 [mrad], ΔPZ = 10 × 15 × tan (2.9 × 10−3) = 0.43
An error of 6 [mm] will occur.

When a light beam is synthesized by using the beam synthesizing means having such synthesizing accuracy, the above-mentioned "optical axis / collimate adjustment" can be performed with the beam synthesizing means (in combination with the beam synthesizing means). Yes (Claim 7). For example, as shown in FIG. 10, when adjusting the optical axis / collimation, the two optical beams 21a and 21b emitted from the two semiconductor lasers 11a and 11b are passed through the beam combining prism 17 and the optical axis (optical The beam may be incident on the position sensor 26 for detecting the beam direction). Note that an adjustment error usually occurs at the time of the “optical axis / collimate adjustment”, but the optical axis adjustment error is corrected by using the liquid crystal deflecting element 28 arranged in the optical path described in the embodiment 1-1. It becomes possible to correct.

Incidentally, in order to obtain a desired beam spot diameter on the surface 16 to be scanned, in many cases a stop (opening) is provided in the middle of the optical path to shape the light beam. For example, as shown in FIGS. 10 and 11, an aperture member 27 having such a diaphragm (opening) is provided in the optical path of the light beam as follows.
It can be arranged on the upstream side (light source side) of the liquid crystal deflecting element 28 (claim 8). As a result, the effective area of the liquid crystal deflecting element 28 can be narrowed (component size can be reduced), and the range in which the optical performance of the liquid crystal deflecting element 28 must be satisfied can be narrowed (the manufacturing process can be simplified). , Yield improvement).

Further, by forming the light beam shaping opening on the incident surface or the exit surface of the liquid crystal deflecting element 28, it is not necessary to separately provide an aperture member.
Therefore, it is possible to reduce the number of parts and improve the alignment accuracy between the opening and the effective area of the liquid crystal deflecting element (claim 9). The opening on the incident surface or the exit surface of the liquid crystal deflecting element 28 may be formed by using a method such as silk printing.

By the way, changes in environment (temperature, humidity, etc.),
Alternatively, each semiconductor laser 11a,
The surface to be scanned 1 is affected by a change in the relative positional relationship (adjustment value) between 11b and the coupling lenses 12a and 12b.
The alignment accuracy of the beam spots in 6 may deteriorate. Even in such a case, the optical scanning device 20 is provided with means (beam spot arrangement detecting means) for detecting the beam spot arrangement or the scanning line interval on the surface 16 to be scanned, and the liquid crystal deflecting element 28 is supplied with an electric signal based on the detection result. By driving / controlling (modulating), it becomes possible to correct the variation in the interval between the beam spots (claim 10). As an example of the beam spot arrangement detecting means, it may be provided as an alternative to the synchronization detecting plate 19 in FIG.

For driving / controlling the liquid crystal deflecting element 28, a feedback system may be constructed so that the detected beam spot arrangement has a desired value. Alternatively, if the change in the beam spot arrangement due to the environmental change / change over time is known in advance (design or calculation), a table according to the change amount is stored in the memory of the control system, and A configuration (open loop) for driving / controlling the liquid crystal deflecting element 28 based on the above may be used.

The configuration of the beam spot arrangement detecting means 19 is, for example, [Patent Document 9] Japanese Patent Laid-Open No. 9-3252.
The detection means and the like described in Japanese Unexamined Patent Publication No. 88, "Multi-beam scanning device" may be used. Further, as an alternative to the above-mentioned beam spot arrangement detecting means 19, by using a detecting means such as a CCD, not only the beam spot arrangement (relative positional relationship between the beam spots) on the surface 16 to be scanned, Since the absolute position of each beam spot can also be detected, the absolute position of the beam spot can be adjusted by driving / controlling the liquid crystal deflecting element 28.

As described above, as one embodiment of the optical scanning device (multi-beam scanning device) according to the present invention, the above-mentioned Example 1-
In 1 and 1-2, the two-beam scanning device has been described, but the number of light beams scanned at one time may be one (single beam), or may be three or more.

[Embodiment 2] Next, as a second embodiment of the present invention, the configuration, operation and action of the invention according to claims 1, 11 to 21 will be described in detail based on the illustrated embodiment.
In the following description of the examples, as in the first embodiment, the X direction is along the optical path (optical axis), the Y direction is the main scanning (corresponding) direction, and the Z direction is the sub-scanning (corresponding) direction. And
Further, the “main scanning direction” and the “sub-scanning direction” mean the direction in which the beam spot is scanned on the surface to be scanned and the direction orthogonal thereto, but in the present embodiment, the (scanned The directions corresponding to the main scanning direction of the surface and the sub scanning direction are called (in a broad sense) the "main scanning direction" and the "sub scanning direction", respectively.

(Embodiment 2-1) FIG. 12 is a view showing an embodiment of the present invention and is a perspective view showing an optical arrangement of an optical scanning device. Further, FIG. 13 is a plan view of a main part showing an optical arrangement in the main scanning section of the optical scanning device shown in FIG. 12 and 13, at least "two sets of semiconductor lasers 11a and 11b, coupling lenses 12a and 12b, and optical path deflecting means 29a and 29b" are included in the "light source device 18".
However, the present invention is not limited to such a configuration. The semiconductor lasers 11a and 11b may be single beam semiconductor lasers having a single light emitting point or multi-beam semiconductor lasers (semiconductor laser array) having a plurality of light emitting points.

The laser light emitted from the semiconductor lasers 11a and 11b is coupled by the coupling lenses 12a and 12b, and two light beams (laser beams) are provided.
21a and 21b. Then, the two light beams 21a and 21b emitted from the light source device 18 are imaged in the sub-scanning direction and are long in the main scanning direction on the deflection reflection surface of the polygon mirror 14 which is a deflector by the action of the cylindrical lens 13. ) After being formed as a line image, the two scanning lenses 15
The surface to be scanned (for example, a photoconductor drum) 16 is formed by the scanning optical system 15 composed of a and 15b and the folding mirror 15c.
The upper part is scanned as a beam spot.

When the optical scanning device 20 of this embodiment is used as an optical writing device of an image output device, the light beam is modulated in accordance with the output image data, but an electric signal ( The synchronization signal) is obtained when the light beam is incident on the synchronization detection plate (synchronization detection sensor) 19. The two light beams 21a and 21b incident on the deflector (polygon mirror) 14 are not parallel to each other in the main scanning cross section (claim 21). With such a configuration, it is possible to secure an interval PY between the two beam spots on the surface 16 to be scanned in the main scanning direction. Therefore, the synchronization detection signal for setting the modulation start timing can be detected independently for both light beams using one synchronization detection plate 19.

Normally, in the main scanning section, the scanning optical system 15 is reflected after being reflected by the deflective reflecting surface of the polygon mirror 14.
The light beam incident on is a parallel light beam or a “weak” divergent light beam or a “weak” convergent light beam. Beam waist is formed). Therefore, it is incident on the deflecting and reflecting surface of the polygon mirror 14.
When the two light beams are parallel to each other, that is, when the two light beams incident on the scanning optical system 15 are parallel to each other, the two light beams are generated by the action of the scanning optical system 15 near the surface to be scanned. (The beam pitch PY in the main scanning direction becomes 0), it becomes impossible to independently obtain the synchronization detection signal.

In FIG. 13, two beams intersect each other in the vicinity of the deflecting / reflecting surface of the polygon mirror 14 at “angle θ (= 2θ)” (non-parallel in the main scanning section). This makes it possible not only to independently detect the synchronization detection signal, but also to suppress the occurrence of deviations in the optical characteristics (field curvature, magnification error, etc.) between the two beams. When the scanning optical system 15 has a sufficient constant velocity scanning property (fθ characteristic), the above two beam spot intervals (main scanning direction): PY are: PY = FY × θ (FY: scanning The focal length of the optical system 15 in the main scanning direction). For example, FY = 220 [mm], Θ = 1 ° =
In the case of 0.01745 [rad], since PY = FY × Θ = 220 × 0.01745 = 3.8 [mm], the two light beams are synchronized even if the “low-cost” synchronization detection sensor is used. The detection signal can be detected independently.

As described in the first embodiment, FIG.
As shown in, the two beam spots (BS1, BS2) on the surface 16 to be scanned are required to maintain a predetermined interval (beam pitch: PZ) in the sub-scanning direction according to the scanning density. In order to set this beam pitch, the angle φ formed by the two light beams 21a and 21b as shown in FIG. 4 may be set. If the sub-scanning magnification of the entire scanning optical system is mZ and the focal length of the coupling lens is fcol, then PZ = mZ × fcol × tanφ, and the angle φ is very small, so if tanφ≈φ, then PZ = It is represented by mZ × fcol × φ. The beam pitch PZ may fluctuate due to environmental (temperature / humidity) fluctuations, the influence of aging, and the like. The inventions according to claims 11 to 20 are inventions relating to a technique for correcting the changed beam pitch; PZ.

By the way, as shown in FIG. 12 and FIG. 13, as the optical path deflecting means, the optical path deflecting elements 29a and 29b which can be independently driven / controlled are integrated into the optical paths of the two light beams 21a and 21b. It can be provided (claims 1 and 11). The examples shown in FIGS. 12 and 13 are examples in which a “wedge prism” described below is applied as the optical path deflecting element. FIG. 14 is an enlarged view of an optical path deflecting element (wedge prism unit) including a "wedge prism 30" which is a transmissive optical element. In this optical path deflecting element, a wedge-shaped prism 30 is inserted inside a "ring ultrasonic motor 31" driven by a piezoelectric element, and the wedge prism 30 is rotatably driven in a direction indicated by an arrow γ in the figure, whereby an arrow φ The light beam can be deflected (the component in the sub-scanning direction of the light beam can be varied) as shown in FIG.
4). The optical path deflecting elements 29a and 29b composed of two "wedge-shaped prism units" having such a configuration are shown in FIG.
The light source device 18 capable of deflecting the light beam can be realized without increasing the size by holding it by a common holding member 29 as shown in Nos. 2 and 13 and integrating it with the light source device.

By using the ultrasonic motor as described above, a displacement (adjustment value) on the order of nm (nanometer) or μm (micrometer) can be obtained, and a large holding force is generated even when the power is turned off. The adjustment value can be maintained, and other effects can be obtained.

When the apex angle of the wedge prism corresponding to the light beam 21a is αa, the internal refractive index is na, and the rotation angle (angular displacement) γa, the deflection angle φa is φa = (na-1) × αa. Since xsinγa, the amount of movement of the beam spot on the surface to be scanned corresponding to this light beam 21a: Za is: Za = mZ × fcol × φa = mZ × fcol × (na−1) × α
It becomes a × sinγa.

For example, na = 1.5, mZ = 9.5 times,
fcol = 15 [mm], αa = 1 ° = 0.01745 [rad],
In the case of, Za = mZ × fcol × (na-1) × αa × sinγa = 9.5 × 15 × (1.5-1) × 0.01745 × sinγa = 1.24 × sinγa, so rotate γa from -90 ° to + 90 °. The beam spot on the surface to be scanned is ± 1.24
[mm] Can be moved.

On the other hand, the amount of movement of the beam spot on the surface to be scanned: Zb corresponding to the light beam 21b can be calculated in the same manner as follows: Zb = mZ × fcol × φb = mZ × fcol × (nb-1) × α
If b = sinγb, and na = nb = n and αa = αb = α, then γa and γb are appropriately set so that φ = φa−φb = (n−1) × α × (sinγa−sinγb). By setting, PZ
Can be set to a desired value. Of course, the deflection of the light beam may be performed on two light beams, or may be performed on only one light beam.

Next, as a modified example using a transmission type optical element for the optical path deflecting means, an example using a "cylindrical lens" is shown in FIGS. As shown in FIG. 15A, the cylindrical lens 33 is held inside a holding member 29 by a lens holder 35 sandwiched between an elastic member (coil spring) 34 and a piezoelectric element (piezo element) 32. By applying a voltage to the piezo element 32, the displacement Δ
Is generated (FIG. 15C), and the cylindrical lens 3
By moving 3 in the direction indicated by arrow Z in FIG. 15B (in the sub-scan section), the beam can be deflected in the direction indicated by arrow φ. Then, the optical path deflecting elements 29a and 29b composed of two "cylindrical lens units" having such a configuration are held by a common holding member 29 as shown in FIGS. The light source device 18 capable of deflecting the light beam can be realized without increasing the size.

In the above two examples (wedge prism, cylindrical lens), the driving means using the piezoelectric element was used as the actuator of the optical path deflecting element. It is also possible to use a driving means using a pulse motor that operates or a pulse motor that moves straight by a predetermined distance according to an input pulse signal (claim 15). When using a pulse motor, angular displacement (or displacement) proportional to the number of input steps
Therefore, the desired adjustment value can be easily obtained (in some cases, by open loop control). At present, compared to ultrasonic motors and the like, pulse motors are generally general-purpose drive means,
Since it is available at a relatively low cost, the cost of the light source device can be reduced.

(Embodiment 2-2) Next, as another embodiment of the optical path deflecting element, an example using a "reflection type optical element" is shown in FIG.
A description will be given using (a) and (b). FIG. 16A shows FIG.
2 and 13 show an optical system on the front side of the deflector 14 when the optical path deflecting element of the optical scanning device shown in FIGS. 2 and 13 is a reflection type optical element, and FIG. is there. In this optical path deflecting element, a folding mirror 37 (37a, 37b) is used as a reflection type optical element, and by the displacement of a piezoelectric element (piezo element) 32 that generates a displacement proportional to an applied voltage, the folding mirror 37 is held. The mirror 37 rotates about the roller 38 in the direction of the arrow β, so that the light beam is deflected by the angle φ = 2 × β. Two "folded mirror units" with such a configuration
May be held by a common holding member 29 and integrated with the light source device 18 as an integrated structure. In general, when a reflective optical element is used, the beam deflection angle can be increased as compared with the case where a transmissive optical element is used. Therefore, a beam spot with a wide adjustment range (sensitive) It becomes possible to adjust the position.

(Embodiment 2-3) Next, an example using a "liquid crystal element (liquid crystal deflecting element)" as still another embodiment of the optical path deflecting element will be described with reference to FIGS. 17 (a) and 17 (b). To do. 17A and 17B show an example of a four-beam light source device in which four beams are combined by using a "beam combining prism" of [claim 17] described later. FIG. 17A shows a liquid crystal element 40 driven by an electric signal as an optical path deflecting element, which is arranged on the upstream side (light source side) of the beam combining prism 17 in the optical path of the light beam. In 40, the light transmitting portion is divided into four, and each divided portion (effective area) can be independently drive-controlled. In addition, FIG.
The structure (b) has a structure in which four independent liquid crystal elements 40a to 40d are held by a common holding member 29 (claim 1).
6).

When a plurality of photoconductors serving as the surface to be scanned exhibit different sensitivity characteristics (wavelength dependence), it is necessary to make the oscillation wavelength of the semiconductor laser constituting the light source different depending on the corresponding photoconductors. In that case, it becomes necessary to provide a liquid crystal element exhibiting wavelength dependence corresponding to the oscillation wavelength. Therefore, by adopting a structure in which a plurality of independent liquid crystal elements 40a to 40d are held by a common holding member 29 as in the configuration of FIG. 17B, it is possible to arbitrarily deflect laser beams having different wavelengths. Becomes On the other hand, as shown in FIG. 17A, when the wavelength dependency of the liquid crystal element is low (a wide range of wavelengths can be supported), one liquid crystal element 40 can independently modulate each light beam. A configuration having a plurality of effective areas (four areas) is also possible.

Conventionally, as an optical path deflecting means for deflecting a light beam, a mechanical method (moving a mirror, a prism, etc. arranged in the optical path), a method using an electro-optical element (a prism made of an electro-optical element material) The optical path is deflected by using the change in the refractive index of the optical path), the method of using the acousto-optic element (a diffraction grating is generated in the piezoelectric body by ultrasonic waves to deflect the optical path), etc. Although they have been put to practical use, all of them have problems due to the reason that the device becomes large, vibration / noise / heat is generated, and low voltage driving is difficult.

However, as the optical path deflecting means for deflecting the light beam, the liquid crystal element 40 (40a to 40a) described in this embodiment is used.
By using the optical path deflecting element (liquid crystal deflecting element) consisting of d), it becomes possible to downsize the device, suppress the occurrence of vibration, etc., and drive at a low voltage. As an example of the configuration and operation of the liquid crystal element, the configuration and operation of the liquid crystal element shown in FIGS. 5A and 5B already described in Example 1-1 of the first embodiment,
Alternatively, since the configuration and operation of the known liquid crystal deflecting element described with reference to FIGS. 32 to 34 are the same, description thereof will be omitted here.

(Embodiment 2-4) FIG. 18 is a view showing another embodiment of the present invention, and is a perspective view showing a disassembled configuration example of the light source device of the optical scanning device. The configuration of the optical scanning device after the cylindrical lens 13 is the same as that in FIG. As shown in FIG. 18, this "light source device" includes: at least two sets of "semiconductor lasers 11a and 11b;
Coupling lenses 12a and 12b corresponding to them "
And a "first light source unit 41" composed of "a base member 43a that arranges them in a line in the main scanning direction and integrally holds them", and at least two sets of "semiconductor lasers 11c and 11d
Coupling lenses 12c and 12d corresponding to them "
And a "second light source section 42" composed of "a base member 43b for arranging them in a row in the main scanning direction and integrally holding them", and the first light source section 41 and the second light source section. Beam combining means (beam combining prism) 17 for closely emitting a plurality of light beams emitted from 42, the first light source unit 41 and the second light source unit 42, and beam combining means (beam combining prism) ) 17 between them and an optical path deflecting element (for example, a liquid crystal element) 40 (claim 17).

The laser beams emitted from the four semiconductor lasers 11a to 11d are respectively coupled to the corresponding coupling lens 1.
The light beams are coupled by 2a to 12d to become four light beams (laser beams) 21a to 21d. The two beams 21a and 21b emitted from the first light source unit 41 are combined by the beam combining prism 17 in close proximity to the two beams 21c and 21d emitted from the second light source unit 42. By adopting such a configuration, it is possible to expand the degree of freedom in the arrangement of the light sources and reduce the angle (main scanning cross section) Θ at which the two light beams intersect near the deflecting reflection surface of the polygon mirror 14. The effect that the control board for driving / controlling two semiconductor lasers can be integrated can be obtained. Further, it is possible to easily adjust the sub-scanning beam pitch on the surface to be scanned when assembling the light source device and / or the optical scanning device.

The base members 43a and 43b of the first light source unit 41 and the second light source unit 42 are provided with screws 45 (and washers 4).
6) is fixed to the flange 44 by means of 6).
It should be fixed to 4. The beam combining prism 17 may be held by another holding member (not shown).

An example in which a liquid crystal element is used as an optical path deflecting element in a four-beam light source device is the same as in FIGS. 17A and 17B and is as described in Example 2-3. As another example, a four-beam light source device using the "wedge-shaped prism" shown in FIG. 14 as an optical path deflecting element is shown in FIGS. 19 (a) and 19 (b). FIG. 19 (a),
Also in the embodiment shown in FIG. 14B, similar to FIG. 14, a plurality (four) of optical path deflecting elements (wedge prisms 30a to 30a-3).
0d) is held by a common holding member 29 via ring ultrasonic motors 31a to 31d, and has an integral structure. By independently rotating and driving the four wedge prisms 30a to 30d by the ring ultrasonic motors 31a to 31d, the positions of the four beam spots on the surface to be scanned can be adjusted independently.

It should be noted that no matter which optical path deflecting element is used, the four beam spot positions are not adjusted as described above, and the remaining three beam spots are used as a reference with respect to one specific beam spot.
The configuration may be such that one beam spot position (relative position) is adjusted. In this case, it becomes possible to omit the beam deflecting element corresponding to one specific beam spot or the actuator for driving the beam deflecting element.

FIG. 20A shows an example (a diagram in which the beam combining prism 17 is omitted and the optical path is expanded) in which the light source device having the structure shown in FIG. 18 is combined with a scanning optical system.
An example of a beam spot arrangement on the surface 16 to be scanned corresponding to this is shown in FIG. Similarly to the case described with reference to FIGS. 13 and 3, in the configuration shown in FIG. 20, the beam spots BSa to Bs on the scanned surface 16 in the main scanning direction.
In order to secure the interval (Q1 to Q3) of d, it is necessary to make the optical paths of the optical system in front of the deflector (polygon mirror) 14 not parallel to each other. For example, as shown in FIG. 20A, it is possible to optically set four light beams to intersect in the vicinity of the deflecting / reflecting surface of the deflector 14 and set the intersecting angles: Θ1 to Θ3. At this time, there is a relationship of Qj = FY × Θj (j = 1, 2, 3).

Further, as described above, by configuring the light source with the "semiconductor laser and the coupling lens", the characteristics of the light beam (collimating property and optical axis direction) according to the characteristics of the optical system can be easily obtained. It is possible to obtain (claim 18). For example, as shown in FIG. 7 described above, while observing the beam characteristics of the light beam 21 emitted from the semiconductor laser 11 fixed by press fitting into the base member 22 and coupled by the coupling lens 12, the semiconductor laser The position of the coupling lens 12 with respect to 11 may be adjusted and then fixed to the base member 25 with an ultraviolet curable adhesive or the like.

Alternatively, as shown in FIG. 8, a lens cell 23 containing a coupling lens 12 and having a male screw portion is provided.
Is engaged with the female screw portion of the holder member 24 to adjust the relative position in the X direction (left and right direction in the figure; adjustment of the collimation rate), and the Y direction and Z direction of the semiconductor laser 11 held by the base member 25. Relative position adjustment can be performed (vertical direction in the figure and a direction perpendicular to the plane of the drawing; adjustment of emission direction of light beam). Such adjustment of the relative positional relationship between the semiconductor laser and the coupling lens is generally called “optical axis / collimation adjustment” in many cases. Normally, an adjustment error occurs at the time of "optical axis / collimate adjustment", but in the present embodiment, the optical axis adjustment error can be corrected (fine adjustment) by using the optical path deflecting element arranged in the optical path. It will be possible.

Further, as shown in FIG. 21, the optical axis (lens center axis) of the coupling lens 12c (12d) is
By displacing the semiconductor laser 11c (11d) from the emission axis by the distance δz, the optical axis direction of the angle φ can be set in the sub-scanning direction. The relationship between δz and φ is the focal length of the coupling lens 12c (12d):
It is represented by δz = fcol × tanφ using fcol. The semiconductor laser may be a single beam semiconductor laser having a single light emitting point or a multi-beam semiconductor laser (semiconductor laser array) having a plurality of light emitting points.

In order to obtain a desired beam spot diameter on the surface to be scanned, a light beam is often shaped by providing a stop (opening) in the optical path. As shown in FIG. 22, an aperture member 27 provided with such a diaphragm (opening) is used as an optical path deflecting element (for example, a liquid crystal element 40) in the optical path of a light beam.
It can be arranged further upstream (light source side) (claim 19). As a result, the effective area of the optical path deflecting element can be narrowed (component size can be reduced), and the range in which the optical performance of the optical path deflecting element 40 can be satisfied can be narrowed (simplification of manufacturing process, Yield improvement)
Becomes

When the optical path deflecting element is not displaced (translated or rotated) (for example, the liquid crystal element 40), the light beam shaping aperture is provided on the incident surface or the exit surface of the optical path deflecting element. By forming the above-mentioned structure, it is not necessary to separately provide an aperture member. Therefore, it is possible to reduce the number of components and improve the alignment accuracy between the aperture and the effective area of the optical path deflecting element. To form the openings on the incident surface / emission surface of the optical path deflecting element, a method such as silk printing may be used.

(Embodiment 2-5) Due to changes in the environment (temperature, humidity, etc.) or changes over time, the relative positional relationship (adjustment value) between each semiconductor laser and the coupling lens fluctuates. The array accuracy of the beam spots on the surface 16 to be scanned may deteriorate. Even in such a case, the optical scanning device including the light source device according to any one of claims 11 to 19 is provided with means (beam spot arrangement detection means) for detecting the beam spot spot arrangement or the scanning line interval on the surface 16 to be scanned, By driving / controlling (modulating) the beam deflecting element with an electric signal based on the detection result, it becomes possible to correct the variation in the interval of the beam spots. As an example of the beam spot arrangement detection means, it may be provided as an alternative to the synchronization detection plate 19 in FIG.

For driving / controlling the optical path deflecting element, a feedback system may be constructed so that the detected beam spot arrangement has a desired value. Alternatively, if the change in the beam spot arrangement due to the environmental change / time-dependent change is known in advance (design or calculation), a table according to the change amount is prepared in the memory of the control system, and the optical path is based on the table. A configuration (open loop) for driving / controlling the deflection element may be used.

The configuration of the beam spot arrangement detecting means 19 is, for example, [Patent Document 9] Japanese Patent Laid-Open No. 9-3252.
The detection means and the like described in Japanese Unexamined Patent Publication No. 88, "Multi-beam scanning device" may be used. Further, as an alternative to the above-mentioned beam spot arrangement detecting means 19, by using a detecting means such as a CCD, not only the beam spot arrangement (relative positional relationship between the beam spots) on the surface 16 to be scanned, Since the absolute position of each beam spot can also be detected, the absolute position of the beam spot can be adjusted by driving / controlling the optical path deflecting element.

As described above, as one embodiment of the light source device and the optical scanning device (multi-beam scanning device) according to the present invention, in the above-mentioned Examples 2-1 to 2-5, the two-beam light source device and the two-beam scanning device, and Although the four-beam light source device and the four-beam scanning device have been described, the number of light beams scanned at one time may be any number.

[Embodiment 3] Next, as a third embodiment of the present invention, the configuration, operation and action of the invention according to claims 1, 22 to 26 will be described in detail based on the illustrated embodiment.
In the following description of the examples, as in the first and second embodiments, the X direction is the direction along the optical path (optical axis), the Y direction is the main scanning (corresponding) direction, and the Z direction is the sub scanning (corresponding). ) Direction. Further, the "main scanning direction" and "sub-scanning direction" mean the direction in which the beam spot is scanned on the surface to be scanned and the direction orthogonal thereto, but in the present embodiment, at each location of the optical path,
The directions corresponding to the main scanning direction (of the surface to be scanned) and the sub scanning direction (in a broad sense) are the "main scanning direction" and the "sub scanning direction", respectively.
I am calling.

(Embodiment 3-1) FIG. 23A is a diagram showing an embodiment of the present invention and is a perspective view showing an optical arrangement of an optical scanning device. Further, FIG. 23B is a perspective view of a main part showing another configuration example of the light source device of the optical scanning device, and is an example in which a beam combining prism 17 is provided as a beam combining means after the coupling lenses 12a and 12b. . In FIG. 23, "light source device 18" is at least "two sets of semiconductor lasers 11a and 11b and coupling lenses 12a and 1".
2b ”, but is not limited to such a configuration. Further, the semiconductor lasers 11a, 1
1b may be a single beam semiconductor laser having a single light emitting point or a multi-beam semiconductor laser (semiconductor laser array) having a plurality of light emitting points. The laser light emitted from the semiconductor lasers 11a and 11b is coupled by the coupling lenses 12a and 12b to become two light beams (laser beams) 21a and 21b.

Two light beams 2 emitted from the light source device 18
1a and 21b are imaged as line images (imaged in the sub-scanning direction and long in the main scanning direction) on the deflective reflection surface of the polygon mirror 14 which is a deflector by the action of the cylindrical lens 13, and then two sheets are formed. A scanning optical system 15 including scanning lenses 15a and 15b and a folding mirror 15c scans a surface to be scanned (for example, a photosensitive drum) 16 as a beam spot. When this optical scanning device 20 is used as an optical writing device of an image forming apparatus, a light beam is modulated in accordance with output image data. It is obtained when the light beam is incident on the detection plate 19.

23A, unlike the case of FIG. 23B, the beam combining means such as the beam combining prism 17 is not provided, but two light beams are deflected and reflected by the polygon mirror 14. It is constructed so that it intersects at an "angle Θ" in the vicinity. Such a configuration is also considered to be “beams are combined (that is, having a beam combining unit)” in a broad sense. Further, by adopting such a configuration, not only the synchronization detection signal can be detected independently, but also the deviation of the optical characteristics (field curvature, magnification error, etc.) between the two light beams is suppressed. It becomes possible.

In the optical scanning device shown in FIG. 23, the surface to be scanned 1
In order to control the position of the light beam on 6, the optical path deflecting means for deflecting the optical path of the light beam is coupled lens 12.
It is provided in the optical path after a and 12b (claim 22). In this example, a liquid crystal element (liquid crystal deflecting element) 40 (40a, 40b) that can be controlled by an electric signal is used as the optical path deflecting means. However, in order to control the beam spot position on the surface 16 to be scanned. Is an optical path deflecting means (liquid crystal element) 40
The beam may be deflected by driving (40a, 40b) with an electric signal. The liquid crystal element is shown in FIG.
It may be a separated structure as shown in FIG.
It may have an integral structure as shown in (b).

Here, FIG. 24 shows an example of the structure of the liquid crystal element (liquid crystal deflecting element) 40.
Two transparent glass substrates 40-1 each having a transparent electrode 40-2 and an alignment film 40-3, a spacer 40-4, and a liquid crystal 40-5.
The spacer 40-4 so that the alignment films 40-3 face each other.
And the liquid crystal 40-5 is filled in the space between the two glass substrates 40-1. By connecting the drive control system 40-6 to the transparent electrode 40-2 of this liquid crystal element and inputting a rectangular wave or a sine wave as a drive voltage,
The light beam can be deflected. Further, the deflection angle can be adjusted by changing the width (duty) or the amplitude of the rectangular wave or the sine wave. As the configuration of the liquid crystal deflecting element using the liquid crystal element as the deflecting element, as described in Example 1-1 of the first embodiment, the configuration and operation shown in FIGS. The thing of can also be used conveniently.

When controlling the beam spot position on the scanned surface 16 by the liquid crystal element 40 as the optical path deflecting means,
For example, in order to displace the beam spot position by ΔZ in the sub-scanning direction, ΔZ = fcol × mZ × tan φZ, so that φZ = tan ⁻¹ (ΔZ / fcol × mZ), the beam deflection angle in the sub-scanning direction The component: φZ should be generated. Further, to displace the beam spot position by Δy in the main scanning direction, φY = tan ⁻¹ (ΔY / fcol × mY) = tan ⁻¹ (ΔY /
Main scanning direction component of the beam deflection angle: φY.

By the way, the optical scanning device having the structure shown in FIG. 23 has the same structure as the optical scanning device having the structure described in the first embodiment, and the liquid crystal element 40 (4) is used as the optical path deflecting means.
0a, 40b) to deflect the optical path, it is possible to easily realize the adjustment (correction) of the beam spot position on the scanned surface 16. Further, it is possible to correct a temporal change in beam spot position due to a temperature change or the like. Furthermore, there are advantages such as low loss of light quantity and low driving power.

On the other hand, the liquid crystal element generally has a problem that ghost light is likely to be generated due to diffraction. Here, the liquid crystal element can be roughly classified into the following two types. (1) A method in which an applied voltage is applied to a plurality of electrodes to generate a refractive index distribution and the incident light is deflected by a prism effect. (2) A method in which a stripe pattern that functions as a diffraction grating is generated by applying an applied voltage to a plurality of electrodes, and incident light is deflected by the diffraction effect. In any case, since the plurality of electrodes form electrode patterns arranged at substantially equal intervals, diffracted light corresponding to the electrode pitch is generally generated.

In the liquid crystal element 40 having the structure as shown in FIG. 24, the 0th order light of the diffracted light generated by the transparent electrode 40-2 of the liquid crystal element 40 is deflected as the write data.
The primary light, ± secondary light, ... Are unnecessary ghost light.
When such ghost light reaches the surface 16 to be scanned, a ghost image is also generated on the image, which may cause image deterioration. Therefore, in order to remove the ghost light, as shown in FIG. 25, a configuration including a ghost light removing means (for example, a slit opening) 51 for blocking the ghost light is provided between the liquid crystal element 40 and the deflector 14. It is possible (claim 24). Then, as shown in FIG. 25, by arranging the slit openings 51 as ghost light removing means,
Unnecessary ghost light generated by diffraction of the liquid crystal element 40 (± 1
Second light, ± secondary light, ...) Can be easily removed.

Here, the slit opening 51 may have any shape as long as it has an opening for blocking ghost light in the deflection direction of the liquid crystal element 40, and a rectangular opening and two light shielding plates are brought close to each other. It is possible to adopt an opening arranged in such a manner that the longitudinal direction is an infinite opening. The slit opening 51 may be formed by forming a transparent member such as a glass plate with a light-shielding film or vapor deposition means, or by forming a rectangular hole in a flat plate, or using a knife edge or the like. May be. Further, the ghost light shielding member may have a configuration having a step difference in the optical axis direction (for example, the upper knife edge and the lower knife edge are installed at different locations in the optical axis direction).

As shown in FIG. 25, the slit aperture 51 can effectively reduce the ghost light by satisfying the following relational expression (claim 25). L> (1/2) × tan θ × (b + Δ) {b: Total width (diameter) of light beam deflected by liquid crystal element Δ: Total width of slit opening L: Distance between liquid crystal element and slit opening 2θ: In liquid crystal element Of the ghost light generated, + 1st-order light and −
Angle between primary lights}

The ghost light removing means such as the slit opening 51 may be arranged upstream of the beam synthesizing means (light source side) or downstream of the beam synthesizing means (scanned surface side). It may be installed.

(Embodiment 3-2) Next, FIG. 26A is a view showing another embodiment of the present invention and is a perspective view showing an optical arrangement of the optical scanning device. The basic configuration of this optical scanning device is the same as that shown in FIG. 23A, but a transmission type optical element is eccentrically provided as the optical path deflecting means (claim 23). FIG. 26B is a sectional view of an optical path deflecting unit (wedge prism unit) including "wedge prisms 30a and 30b" which are transmissive optical elements.

The optical scanning device having the configuration shown in FIG. 26 has the same configuration as the optical scanning device having the configuration described in Example 2-1 of the second embodiment, and the optical path deflecting means is driven by a piezoelectric element. The wedge-shaped prism 30 is inserted into the "ring ultrasonic motor 31", and is driven to rotate in the direction indicated by the arrow γ in the figure, whereby the light beam is deflected as indicated by the arrow φ (light It is possible to change the sub-scanning direction component of the beam). By holding the two "wedge-shaped prism units" having such a configuration on the common holding member 29, it is possible to realize the optical path deflecting means capable of deflecting the light beam without increasing the size. As an optical path deflector,
Such a transmissive optical element (wedge prism 30a,
In the case of using 30b), unlike the case of using the above-mentioned liquid crystal element, there is no possibility of generating ghost light (diffracted light), and therefore it is not necessary to provide a ghost light removing means.

(Embodiment 3-3) Next, FIG. 27 is a view showing a further embodiment of the present invention and is a plan view showing a schematic structure of an optical scanning device housed in an optical housing. In FIG. 27, an optical housing 5 for housing the optical scanning device
Two light source modules 41 and 42 for emitting a light beam are fixed (held) to the side wall of the three light source modules 41,
The light beams 21 a and 21 b emitted from 42 are combined by the beam combining prism 17 and enter the deflector 14 formed of a polygon mirror through the cylindrical lens 13. An optical path deflecting means 50 (for example, a transmissive optical element or a liquid crystal element) is arranged in the optical path between the beam combining prism 17 and the deflector 14. The optical path deflecting means 50 and the beam combining prism 17 are common. It is fixed (held) to the holding portion 52 (claim 26).

In the case of the configuration of FIG. 27, the first and second light source modules 41 and 42 themselves are light source devices provided with light source means (for example, semiconductor laser) and a coupling lens. The form of such a light source device does not necessarily have to be an integral structure. Further, as shown in the present embodiment, the first and second light source modules (light source devices) 41 and 42 do not need to be fixed to the side wall 54 of the optical housing 53, and are held via, for example, a bracket member, It may be configured to be housed inside the housing.

By adopting such a structure, compared with the case of the light source device having the structure shown in FIG. 18, replacement work at the time of deterioration of the light source (for example, semiconductor laser) can be performed easily, and It is also possible to reduce the number of replacement parts. In addition, a ghost light removing means (not shown) (see FIG.
The slit aperture 51, etc. shown in FIG. 5) is normally arranged on the downstream side (deflector side) of the beam combining prism 17,
When the optical path deflecting means 50 is arranged on the upstream side (light source side) of the beam combining prism 17, the ghost light removing means is arranged on the upstream side (light source side) of the beam combining prism 17 if the layout allows. It may be provided.

Next, FIG. 28 shows another embodiment of the embodiment for explaining claim 26. FIG. 28A shows a cross-sectional view of an essential part of the optical system fixed (held) to the optical housing, and the “light source device” is at least two light source modules 41,
42 and a holding member 55 that holds them.

As this light source module, for example, FIG.
8 (b), at least two sets of “semiconductor lasers 11a and 11b
And coupling lenses 12a, 12 corresponding to them
b ", a" first light source module 41 "composed of" a base member 43a for arranging them in a row in the main scanning direction and integrally holding them, "and at least two sets of" semiconductor lasers 11c and 11d "
And the corresponding coupling lenses 12c, 12
d "and" the second light source module 42 "including" a base member 43b that arranges them in a row in the main scanning direction and integrally holds them "can be employed.

In the example of FIG. 28 (a), a 4-beam scanning device is constructed, but a multi-beam scanning device with a larger number of beams is realized by the number of light source modules or the number of beams emitted from one light source module. can do. As a modified example of FIG. 28A, as shown in FIG. 29, the two light source modules 41 and 42 are directly connected (without the holding member 55) to the side wall 5 of the optical housing 53.
4 may be used.

[Fourth Embodiment] (Example 4-1) Next, an application example of the optical scanning device (multi-beam scanning device) described in the first to third embodiments will be described below. An optical scanning device according to any one of claims 1 to 10 and 20 to 26 of the present invention is provided with a known photosensitive unit (photoconductor) on which an electrostatic latent image is formed, An electrophotographic process including a developing device that visualizes a latent image with toner, a transfer device that transfers the visualized toner image onto recording paper, and a fixing device that fixes the toner image transferred onto the recording paper. When used as an optical writing device of the image forming apparatus used, it is possible to increase the printing speed and increase the density by simultaneously scanning a plurality of beams. In addition, as described above, the surface to be scanned (that is, the photoconductor) 1
Since it is possible to suppress the fluctuation of the light spot arrangement on the image forming device 6, it is possible to obtain a high-quality output image by the image forming apparatus (claim 27).

The timing for detecting the light spot array is
To print out, the operator (serviceman,
The user may press the start button of the image forming apparatus, or if a large number of sheets are to be output, several sheets (~
It may be done for every (tens of sheets). In addition, when an electric signal is not input to the liquid crystal element (liquid crystal deflecting element) during a period other than the time of printing out (during beam scanning), a memory function for storing the previous adjustment value can be added.

As described above, when the optical scanning device 20 of the present invention is used as an optical writing device of an image forming apparatus, an operator (serviceman, user, etc.) can be operated from the operation panel of the main body.
Can be operated so that an output image (evaluation chart) can be output from the image forming apparatus. As the pattern (evaluation chart) of the output image, for example, the pattern described in [Patent Document 10] Japanese Patent Laid-Open No. 10-62705, “Evaluation chart and image recording device” may be prepared.

In this way, the operator confirms the image quality by the output image, so that not only the influence of the variation of the beam spot arrangement in the optical scanning device on the output image but also the steps of development / transfer / fixing, etc. It is possible to correct the deterioration of the output image, including the effect of the effect on the output image (claim 28). Further, it is possible to omit one or both of the beam spot arrangement detection means and the control means, and the cost of the optical scanning device can be reduced.

In the present invention, the time interval (interval) for detecting the beam spot array and adjusting the deflection of the light beam is at most every one image output or every several to several tens of sheets, or one job (batch). Every time. Therefore, the time for deflecting and adjusting the light beam does not matter even if it is about several milliseconds to several hundreds of milliseconds. Therefore, unlike the case of the prior art (6) for correcting the scanning pitch unevenness due to the rotation unevenness of the photoconductor drum: [Patent Document 6] (high-speed response is required), it is necessary to form the liquid crystal layer in multiple layers. There is no. Similarly, in the prior art (5): [Patent Document 5], unlike the case of [Patent Document 5], it is not necessary to provide a detection unit for detecting the peripheral speed of the photoconductor.

When the above-mentioned image forming apparatus is applied to a multi-function machine having both the functions of a printer and a copying machine (copy machine), a printer mode (a state in which the multi-function machine is used as a printer) and a copy mode (the multi-function machine is used as a copying machine). Condition to use)
Therefore, the pixel density may be switched. For example, "600 dpi in printer mode and 400 d in copy mode.
By switching the pixel density like "pi", the pixel density suitable for each mode can be realized. Also,
An operator issues a command to switch the pixel density from an operation panel or the like provided in the image forming apparatus, so that "high image quality compatible (1200 dpi)" is selected according to the purpose of use (function required).
There are also cases where it is desired to switch the pixel density, such as "⇔ high speed (multi-output number) correspondence (600 dpi)". In such a case, the pixel density can be easily switched by driving / controlling the optical path deflecting element provided in the image forming apparatus (claim 31).

In an image forming apparatus such as a digital color copying machine or a color printer, each color (for example, black: K, cyan: C, magenta: M, yellow: Y).
Corresponding to the photosensitive means (for example, the photosensitive drum 5K, 5C,
A tandem system in which 5M and 5Y) are arranged in series in the conveyance direction of an image recording medium (for example, recording paper) is often used. In this case, as shown in FIG. 30A, the optical scanning device corresponding to each color is separately provided (10K, 10C, 10M, 1).
0Y) or a common body (10A) as shown in FIG. 30 (b). Alternatively, FIG. 30 (c)
Alternatively, as shown in FIG. 30 (d), a configuration (10A1, 10A2) or (10B1,1) in which the optical scanning device is integrated.
0B2) may be used. 30 (a) to 30 (d)
Although only the photoconductor drums 5K, 5C, 5M and 5Y and the optical scanning device are shown in the figure, the photoconductor drums 5K, 5C and 5Y are shown.
Known charging devices, developing devices, transfer devices, cleaning devices, static eliminators, etc. are arranged around M and 5Y, and charging and light charging are performed on the respective photosensitive drums 5K, 5C, 5M and 5Y. Black through the electrophotographic process of writing and developing,
Cyan, magenta, and yellow toner images are formed, and the toner images of the respective colors are sequentially superimposed and transferred onto an image recording medium (for example, recording paper) that is sequentially conveyed between the four photosensitive drums. The recording paper on which the four color toner images have been transferred is conveyed to a fixing device (not shown), and the fixing device fixes the image on the recording paper to obtain a color image. With such a configuration, it is possible to obtain an output image at a speed four times higher than that in the case of a one-photoreceptor-drum type image output device (writing is required four times for four colors). Becomes

Here, the optical scanning device corresponding to each color is
We call them K, 10C, 10M, and 10Y. When the number of beams emitted from each of the optical scanning devices 10K, 10C, 10M, and 10Y is one, the image forming apparatus to which the optical scanning device is applied provides full color (4 colors).
Images can be obtained. On the other hand, at least one of the four optical scanning devices (for example, the optical scanning device 10K corresponding to black) is used as the four-beam optical scanning device of the present invention, and the optical scanning is performed only by the optical scanning device to obtain a full color image. It is possible to increase the density by four times as compared with the case of image. Or recording medium transport speed (and process speed)
If is changed to 4 times, the number of output images can be increased to 4 times. Also, even in full-color images,
Since a character image is often written in black and a high resolution is often required, it is added to the above-mentioned four-beam optical scanning device 10K (black) and other optical scanning devices (10C, 10M, 10Y; By writing 1 beam) at the same time, it is possible to obtain a higher-quality output image even in an image in which characters / photographs / line drawings are mixed (claim 29).

(Embodiment 4-2) Next, FIG.
FIG. 3 is a schematic configuration diagram of a main part of an image forming apparatus showing an embodiment. In the present example, as shown in FIG.
Optical scanning device (multi-beam scanning device) having the configuration described in 1.
Two optical scanning devices 20 are used, and the two optical scanning devices (multi-beam scanning device) 20 are arranged in parallel in the main scanning direction with respect to the surface to be scanned (photosensitive drum) 16 to divide the effective writing width. Scanning. In this way, by arranging the two optical scanning devices (multi-beam scanning devices) 20 in parallel in the main scanning direction, the effective writing width can be increased. Further, if the effective writing width is the same, the optical element and the deflector can be downsized, the beam waist position variation due to mechanical tolerance and temperature variation can be reduced, and the wavefront aberration can be reduced. Although only the surface to be scanned (photosensitive drum) 16 and the two optical scanning devices 20 are shown in FIG. 31, a known charging device, developing device, transfer device, and cleaning device are provided around the photosensitive drum 16. , A static eliminator, etc. are provided, and a toner image is formed on the photoconductor drum 16 through an electrophotographic process of charging, optical writing, and development, and the toner image is transferred to the photoconductor drum 16 and the transfer device. It is transferred onto an image recording medium (for example, recording paper) conveyed between (not shown). Then, the recording paper on which the toner image is transferred is conveyed to a fixing device (not shown), and the image is obtained by fixing the image on the recording paper by the fixing device.

[0132]

As described above, in the optical scanning device according to the first aspect, at least one light beam scanned on the surface to be scanned by the optical path deflecting means arranged in the optical path of the light beam. By changing the position of, the beam spot position on the surface to be scanned can be adjusted. In the optical scanning device according to the second aspect, since the light beam can be deflected by using a liquid crystal element (liquid crystal deflecting element) which can be controlled by an electric signal as the optical path deflecting means, the apparatus becomes large and vibration / noise / The beam spot arrangement on the surface to be scanned can be adjusted without causing heat generation and by driving at a low voltage. In the optical scanning device according to claim 3, in addition to the effect of claim 2, since the light beam can be independently deflected in two orthogonal directions, the beam spot arrangement on the surface to be scanned is subjected to main scanning / sub scanning. It can be adjusted independently of the direction. In the optical scanning device according to the fourth aspect, in addition to the effect of the second aspect, since a plurality of effective areas are provided on one element, it is possible to reduce the number of parts and improve the positioning accuracy. In the optical scanning device according to a fifth aspect, in addition to the effect of the second aspect, since the light source is composed of at least a semiconductor laser and a coupling lens corresponding to the semiconductor laser, the light is emitted according to the characteristics of the subsequent optical system. It is possible to easily adjust the beam characteristics of the light beam (collimating property, emission optical axis direction). In addition to the effect of claim 2 or 4, the optical scanning device according to claim 6 is configured to emit a plurality of light beams from a plurality of light sources different from each other. The angle θ at which the two light beams intersect in the vicinity of the deflecting / reflecting surface of the deflector can be reduced, and the control substrate for driving / controlling the two semiconductor lasers can be integrated. To be In the optical scanning device according to claim 7, in addition to the effect of claim 5, relative position adjustment / fixing (optical axis / collimate) of the semiconductor laser and the corresponding coupling lens is taken into consideration in consideration of the combining error of the beam combining means. Since the adjustment is performed, the influence of the combining error of the beam combining means can be effectively absorbed (corrected) (at the time of adjusting the optical axis / collimator). In the optical scanning device according to the eighth aspect, in addition to the effect of the second aspect, since the aperture for beam shaping is arranged on the upstream side of the liquid crystal deflecting element, the size of the effective area of the liquid crystal deflecting element can be minimized. can do. In the optical scanning device according to claim 9, in addition to the effect of claim 8, since an opening for beam shaping is formed on the incident surface or the exit surface of the liquid crystal deflecting element, the number of parts is reduced and the opening and the liquid crystal deflecting element are effective. It is possible to improve the positioning accuracy of the area. In the optical scanning device according to claim 10, claim 2
In addition to any one of the effects 1 to 9, it is possible to detect the beam spot arrangement on the surface to be scanned and adjust the variation by feedback control, so that the deterioration of the beam spot arrangement due to temperature change / time change is effective. Can be suppressed.

In the light source device of the optical scanning device according to the eleventh aspect, since the plurality of optical path deflecting elements for adjusting the beam spot position on the surface to be scanned are integrally structured, the light source device can be downsized. You can In the light source device according to the twelfth aspect, in addition to the effect of the eleventh aspect, since the optical path deflecting element is configured by the transmission type optical element, the beam spot position adjustment with high resolution (although the adjustment range is narrow) is high. Is possible. In the light source device according to the thirteenth aspect, in addition to the effect of the eleventh aspect, since the optical path deflecting element is constituted by the reflection type optical element, it is possible to adjust the beam spot position with a wide adjustment range. In the light source device according to claim 14, in addition to the effect of claim 12 or 13, since the optical path deflecting element is driven by utilizing the displacement of the piezoelectric element (piezo element) proportional to the applied voltage, a desired adjustment value is obtained. Can be achieved with high resolution. Further, when the optical path deflecting element is driven by using the ring ultrasonic motor,
In addition to the above effects, it is possible to secure a large holding force even when the power is turned off, and it is possible to suppress the occurrence of fluctuations in adjustment values due to vibrations / impacts generated by the image forming apparatus main body or the writing apparatus. . In the light source device according to the fifteenth aspect, in addition to the effect of the twelfth or thirteenth aspect, since the optical path deflecting element is driven by a pulse motor that generates a displacement (or an angular displacement) proportional to the number of input pulses, a desired adjustment is made. It is possible to obtain a value. Further, since the light source device is configured by using a general-purpose (low cost) pulse motor, the cost of the light source device can be reduced. In the light source device according to claim 16, in addition to the effect of claim 11, since a liquid crystal element modulated by an electric signal is used as an optical path deflecting element, reliability is high (no movable part) and environmental load is reduced. A light source device capable (low power consumption) can be provided. Further, it is possible to arbitrarily deflect a plurality of laser beams having different wavelengths. In the light source device according to claim 17, in addition to the effect according to any one of claims 11 to 16, the light source device is divided into a first light source part and a second light source part, and an emission beam from them is beamed. Since the composition is made by using the composition means, the initial adjustment can be facilitated, the degree of freedom of the light source arrangement can be increased, and the LD control / driving substrate can be shared. In the light source device according to claim 18, in addition to the effect according to any one of claims 11 to 17, the light source is composed of a semiconductor laser and a coupling lens.
The beam characteristics (collimation rate, optical axis direction) of the outgoing beam can be arbitrarily (and easily) set (adjusted). In the light source device according to claim 19, in addition to the effect according to any one of claims 11 to 18, since the opening for shaping the light beam is arranged on the upstream side (light source side) of the optical path deflecting element, the beam deflecting element is provided. The effective area of can be narrowed. Claim 20
An optical scanning device comprising a light source device according to any one of claims 1 to 10 detects a beam spot arrangement (sub-scanning beam pitch) on a surface to be scanned, and drives an optical path deflecting element based on the detection result. Since (feedback adjustment) can be performed, it is possible to correct variations in the beam spot arrangement due to environmental variations, changes over time, and the like. The optical scanning device according to a twenty-first aspect has the effect of the twentieth aspect,
In the main scanning section, it is incident on the deflecting / reflecting surface of the deflector 2
Since the light beams of the book are made non-parallel to each other,
The beam pitch of the beam in the main scanning direction can be secured, and the synchronization detection signal can be obtained independently.

In the optical scanning device according to claim 22,
By deflecting the optical path of the light beam using the optical path deflecting means, the beam spot position on the surface to be scanned can be adjusted. In the optical scanning device according to the twenty-third aspect, in addition to the effect of the twenty-second aspect, since the optical path deflecting element is composed of a transmission type optical element, a high resolution (high accuracy) beam spot position (although the adjustment range is narrow). Adjustment is possible. In the optical scanning device according to a twenty-fourth aspect, in addition to the effect of the twenty-second aspect, unnecessary light beams are scanned by removing ghost light which is generated in principle in a liquid crystal element by using a slit opening. It is possible to prevent reaching the surface. In the optical scanning device according to a twenty-fifth aspect, in addition to the effect of the twenty-fourth aspect, the arrangement position of the slit aperture is defined by an aperture relational expression including a full width of the light beam, a diffraction angle of ghost light (diffracted light), and a slit aperture width. The ghost light can be effectively shielded by setting the position that satisfies the above condition. According to the optical scanning device of claim 26,
In addition to the effect of 5, the configuration in which the optical path deflecting unit is separated from the light source device facilitates the component replacement work when the light source deteriorates, and can reduce the number of component replacement points.

In an image forming apparatus according to a twenty-seventh aspect, the optical scanning apparatus according to any one of the first to tenth aspects and the twenty to twenty-sixth aspects is used for the optical scanning of the image forming apparatus using an electrophotographic process. Since it can be used as a device and can scan a plurality of light beams at the same time, it is possible to increase the printing speed and increase the density. Further, in order to achieve the same printing speed / scanning density as that of the single beam light source device, it is possible to reduce the number of revolutions of the deflector such as a polygon mirror, which leads to reduction of power consumption and generation of vibration / noise / heat. This leads to a reduction in the load on the environment. In the image forming apparatus according to claim 28,
In addition to the effect of claim 27, since the operator judges the image quality based on the output image on the recording medium and drives / controls the optical path deflecting element, the influence of processes such as development / transfer / fixing on the output image is affected. In addition, the deterioration of the output image can be corrected, and one or both of the beam spot arrangement detection unit and the control unit can be omitted, and the cost of the optical scanning device can be reduced.
The image forming apparatus according to claim 29,
In addition to the effect of 28, since the optical scanning device of the present invention is used as an optical scanning device of a tandem type multicolor image forming apparatus using an electrophotographic process, it is possible to increase the density of monochromatic and multicolor output images. / Higher speed and higher quality output image can be achieved. In the image forming apparatus according to claim 30, in addition to the effect according to claim 27 or 28, a plurality of optical scanning devices are provided, and the plurality of optical scanning devices are arranged in series in the main scanning direction with respect to one photosensitive unit. By doing so, it is possible to provide the image forming apparatus in which the color shift of the output image is small and the image deterioration at the joint is small. In addition, claim 31
In the image forming apparatus described in the above, in addition to the effect according to any one of claims 27 to 28, according to a mode (copy mode, printer mode, etc.) of the image forming apparatus and a purpose of use (high image quality correspondence, high speed correspondence, etc.) It is possible to switch the pixel density.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention and is a perspective view showing an optical arrangement of an optical scanning device.

2 is a main part plan view showing an optical arrangement and an optical path in a main scanning section of the optical scanning device shown in FIG.

FIG. 3 is a diagram showing an example of a beam spot arrangement on a surface to be scanned by two light beams.

FIG. 4 is a diagram showing an angle formed by two light beams emitted from a light source (an emission angle of two light beams projected onto a sub-scan section).

FIG. 5 is an explanatory diagram showing an example of the configuration and operation of a liquid crystal deflecting element.

FIG. 6 is a view showing another embodiment of the present invention, and is a perspective view showing only an optical system in front of the deflector of the optical scanning device.

FIG. 7 is a cross-sectional view showing a configuration example of a light source used in the optical scanning device of the present invention.

FIG. 8 is a cross-sectional view showing another configuration example of a light source used in the optical scanning device of the present invention.

FIG. 9 is an explanatory diagram of a combining error in the beam combining prism.

FIG. 10 is an explanatory diagram of a method of correcting a combining error of a beam combining prism when adjusting an optical axis and a collimator.

FIG. 11 is an explanatory diagram of an arrangement position of an aperture member that shapes a light beam.

FIG. 12 is a view showing another embodiment of the present invention and is a perspective view showing an optical arrangement of an optical scanning device.

13 is a plan view of relevant parts showing an optical arrangement in a main scanning section of the optical scanning device shown in FIG.

14 is a diagram showing an example of an optical path deflecting element used in the optical scanning device shown in FIG. 12, and is a schematic cross-sectional view of the optical path deflecting element formed of a wedge prism that is a transmissive optical element.

15 is a diagram showing another example of the optical path deflecting element used in the optical scanning device shown in FIG. 12, and is a structural explanatory view of the optical path deflecting element configured by a cylindrical lens which is a transmissive optical element.

16 is a diagram showing another example of the optical path deflecting element used in the optical scanning device shown in FIG. 12, and is a configuration explanatory view of the optical path deflecting element using a reflective optical element.

17 is a diagram showing another example of the optical path deflecting element used in the optical scanning device shown in FIG. 12, and is a configuration explanatory diagram of the optical path deflecting element using a liquid crystal element.

FIG. 18 is a perspective view showing an exploded configuration example of a light source device having a configuration in which first and second light source sections, an optical path deflecting element, and beam combining means are integrated.

FIG. 19 is a structural explanatory view showing an example of a four-beam light source device using a wedge prism as an optical path deflecting element.

20 is a diagram showing an optical system arrangement and a beam spot arrangement on a surface to be scanned when the light source device shown in FIG. 18 is combined with a scanning optical system.

FIG. 21 is an explanatory diagram of an optical axis direction setting method of a light source device having a configuration in which a light source unit, an optical path deflecting element, and a beam combining unit are integrated.

FIG. 22 is an explanatory diagram of an arrangement position when an aperture member that shapes a light beam is provided in the light source device.

FIG. 23 is a diagram showing another embodiment of the present invention,
FIG. 3A is a perspective view showing the optical arrangement of the optical scanning device, and FIG.
FIG. 6 is a perspective view showing another configuration example of the light source device of the optical scanning device.

FIG. 24 is a diagram showing an example of generation of ghost light (diffracted light) in a liquid crystal element.

FIG. 25 is a diagram showing an example of shielding ghost light (diffracted light) by ghost light removing means.

FIG. 26 is a view showing another embodiment of the present invention, (a)
FIG. 3 is a perspective view showing an optical arrangement of the optical scanning device, and FIG. 6B is a cross-sectional view of essential parts showing a configuration example of an optical path deflecting means of the optical scanning device.

FIG. 27 is a view showing still another embodiment of the present invention,
FIG. 2 is a plan view showing a schematic configuration of an optical scanning device housed in an optical housing.

FIG. 28 is a view showing still another embodiment of the present invention,
It is explanatory drawing of a structure of the light source part of the optical scanning device accommodated in the optical housing.

FIG. 29 is a view showing still another embodiment of the present invention,
It is explanatory drawing of a structure of the light source part of the optical scanning device accommodated in the optical housing.

FIG. 30 is an explanatory diagram of a schematic configuration of an image forming apparatus according to the present invention.

FIG. 31 is a schematic configuration diagram of an essential part of an image forming apparatus according to the present invention.

FIG. 32 is a diagram for explaining an example of the configuration and operation of a liquid crystal deflecting element.

FIG. 33 is a diagram for explaining another example of the configuration and operation of the liquid crystal deflecting element.

FIG. 34 is a diagram for explaining still another example of the configuration and operation of the liquid crystal deflecting element.

[Explanation of symbols]

11a, 11b, 11: Semiconductor laser (or semiconductor laser array) 12a, 12b, 12: Coupling lens 13: Cylindrical lens 14: Polygon mirror (deflector) 15: Scanning optical system 16: Photosensitive drum (scanned surface) 17: Beam synthesizing prism (beam synthesizing means) 18: Light source device 19: Synchronous signal detecting means (synchronous detection plate) (or beam spot array detecting means) 20: Optical scanning device (multi-beam scanning device) 21a, 21b, 21: light beam 22: holding member 23: lens cell 24: holder member 25: base member 26: position sensor 27: aperture member (aperture, aperture) 28a, 28b, 28: liquid crystal deflecting element (optical path deflecting means) 29a, 29b : Optical path deflecting element (optical path deflecting means) 29: Holding members 30, 30a, 30b, 30 , 30d: Wedge prism (transmissive optical element) 31: Ring ultrasonic motor 32: Piezo element (piezoelectric element) 33: Cylindrical lens (transmissive optical element) 34: Elastic member (coil spring) 35: Lens holder 36: Support members 37a, 37b: Folding mirror (reflection type optical element) 38: Roller 39: Mirror holders 40, 40a, 40b, 40c, 40d: Liquid crystal element (optical path deflecting means) 41: First light source unit 42: Second Light source part 43: Base member 44: Flange 45: Screw 46: Washer 50: Optical path deflecting means 52: Holding part 53: Optical housing 54: Side wall 55: Holding member

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoru Ito             1-3-3 Nakamagome, Ota-ku, Tokyo, stock             Company Ricoh (72) Inventor Tomohiro Nakajima             1-3-3 Nakamagome, Ota-ku, Tokyo, stock             Company Ricoh F-term (reference) 2C362 AA03 AA10 AA13 AA26 AA34                       AA40 AA42 AA43 BA58 BA68                       BA71 BA83 BA86 BA90 BB28                       BB46 DA03                 2H045 AA01 BA02 BA22 BA33 CB65                       DA02                 5C051 AA02 CA07 DB30 DC04 DE24                 5C072 AA03 DA21 HA06 HA11 XA05

Claims (31)

[Claims] 1. An optical scanning device which simultaneously scans a surface to be scanned with a plurality of light beams emitted from a light source in a main scanning direction by an optical path deflecting means arranged in an optical path of the light beam. An optical scanning device, wherein the position of at least one light beam scanned above is variable. 2. The optical scanning device according to claim 1, wherein a liquid crystal deflecting element including a liquid crystal element controllable by an electric signal is used as the optical path deflecting means, and the surface to be scanned is scanned by the liquid crystal deflecting element. An optical scanning device characterized by varying the position of at least one light beam. 3. The optical scanning device according to claim 2, wherein the liquid crystal deflecting element is capable of independently deflecting a light beam in two directions orthogonal to each other. 4. The optical scanning device according to claim 2, wherein the liquid crystal deflecting element has a plurality of effective areas which can be independently modulated on one element. 5. The optical scanning device according to claim 2, wherein the light source includes at least a semiconductor laser serving as a light emitting point and a coupling lens for coupling laser light emitted from the semiconductor laser. An optical scanning device characterized by the above. 6. The optical scanning device according to claim 2, wherein light beams emitted from a plurality of different light sources are combined by a beam combining means. 7. The optical scanning device according to claim 6, wherein the light source comprises at least a semiconductor laser serving as a light emitting point and a coupling lens for coupling laser light emitted from the semiconductor laser. An optical scanning device, characterized in that, when the semiconductor laser and a coupling lens corresponding thereto are assembled (position adjustment / fixation), a composition error of a beam composition means is corrected. 8. The optical scanning device according to claim 2, wherein an aperture member having an opening for beam shaping is arranged upstream of the liquid crystal deflecting element (light source side) in the optical path of the light beam. Optical scanning device. 9. The optical scanning device according to claim 8, wherein an opening for beam shaping is formed on an incident surface or an emission surface of the liquid crystal deflecting element. 10. The optical scanning device according to claim 2, wherein a plurality of light beams emitted from a light source are simultaneously scanned as light spots on a surface to be scanned. The scanning device has a detection unit that detects the positions of a plurality of light spots that are simultaneously scanned on the surface to be scanned, and a drive unit that drives / controls the liquid crystal deflection element based on the detection result. An optical scanning device characterized by changing the positions of two light spots. 11. The optical scanning device according to claim 1,
A light source device for emitting a plurality of light beams, comprising: a plurality of optical path deflecting means for independently deflecting each of the light beams corresponding to the light beams emitted from the plurality of light sources. The light source device is characterized in that the deflecting means has an integral structure. 12. The light source device according to claim 11, wherein the optical path deflecting means is a transmissive optical element disposed in the optical path. 13. The light source device according to claim 11, wherein the optical path deflecting means is a reflective optical element disposed in the optical path. 14. The light source device according to claim 12, wherein the transmissive optical element or the reflective optical element is driven by a driving unit using a piezoelectric element. 15. The light source device according to claim 12, wherein the transmissive optical element or the reflective optical element is a pulse motor that rotates a predetermined angle according to an input pulse signal, or a predetermined distance according to an input pulse signal. A light source device characterized by being driven by a driving means using a pulse motor that travels straight. 16. The light source device according to claim 11, wherein the optical path deflecting means is a liquid crystal element driven by an electric signal. 17. The light source device according to claim 11, wherein a plurality of light sources are arranged in a line in the main scanning direction, and a first light source unit integrally holding them is provided. A second light source unit configured in the same manner as the first light source unit, and beam combining means for closely emitting the light beams emitted from the first light source unit and the second light source unit. A light source device characterized by the following. 18. The light source device according to claim 11, wherein the plurality of light sources are composed of a plurality of semiconductor lasers and a coupling lens corresponding thereto. Light source device. 19. The light source device according to claim 11, wherein an aperture member having an opening for shaping a light beam is provided on the upstream side (light source side) of the optical path deflecting means. A light source device characterized by the above. 20. An optical scanning device comprising the light source device according to claim 11 and scanning a plurality of light beams emitted from a light source as a light spot on a surface to be scanned. An optical scanning device comprising: a detection unit that detects the arrangement of a plurality of light spots on the surface to be scanned and a drive unit that drives / controls the optical path deflecting unit based on the detection result. 21. An optical scanning device according to claim 20, wherein:
In a light scanning device in which a plurality of light beams emitted from a light source are deflected and reflected by a deflector and scanned as a light spot on a surface to be scanned by a scanning imaging optical system, a plurality of light beams incident on the deflector ( Is the chief ray of
An optical scanning device, which is not parallel to each other in a main scanning section. 22. The optical scanning device according to claim 1, further comprising a light source device including a plurality of light source means, and a beam combining means for combining a plurality of light beams emitted from the light source device.
An optical scanning device comprising: a deflector for deflecting a plurality of light beams combined by the beam combining means; and a scanning means for guiding the plurality of light beams deflected by the deflector onto a surface to be scanned. An optical scanning device comprising an optical path deflecting means for deflecting an optical path of the light beam between the light source means and the beam combining means in order to control the position of the light beam on the scanning surface. 23. The optical scanning device according to claim 22, wherein the optical path deflecting means includes a transmissive optical element in a decentered manner. 24. The optical scanning device according to claim 22, wherein the optical path deflecting unit is a liquid crystal element controllable by an electric signal, and a ghost light removing unit for removing ghost light generated in the liquid crystal element ( An optical scanning device comprising a slit opening) between the liquid crystal element and the deflector. 25. An optical scanning device according to claim 24, wherein an aperture stop (aperture) for shaping a light beam is provided in an optical path upstream of the optical path deflecting means (light source means side), and the following relational expression is satisfied. An optical scanning device characterized by: L> (1/2) × tan θ × (b + Δ) {b: Total width (diameter) of light beam deflected by liquid crystal element Δ: Total width of slit opening L: Distance between liquid crystal element and slit opening 2θ: In liquid crystal element Of the ghost light generated, + 1st-order light and −
Angle between primary lights} 26. An optical scanning device having a structure in which the optical scanning device according to claim 22 is housed in an optical housing, wherein the light source device is fixed or held on a side wall of the optical housing. The optical scanning device is characterized in that the optical path deflecting means and the beam synthesizing means are fixed or held by a common holding portion inside the optical housing. 27. An optical scanning device according to any one of claims 1 to 10 and 20 to 26, comprising: a photosensitive means for forming an electrostatic latent image by the optical scanning device; An image forming apparatus comprising: a developing unit that visualizes a latent image with toner; and a transfer unit that transfers the visualized toner image to a recording medium. 28. The image forming apparatus according to claim 27, wherein an operator drives / controls the optical path deflecting element based on an output image on the recording medium. 29. The image forming apparatus according to claim 27 or 28, wherein the image forming apparatus has a plurality of photosensitive means serving as a surface to be scanned. 30. The image forming apparatus according to claim 27, further comprising a plurality of the optical scanning devices, wherein one photosensitive unit is provided.
An image forming apparatus comprising a plurality of optical scanning devices arranged in series in a main scanning direction. 31. The image forming apparatus according to claim 27, wherein the pixel density is switchable.