JPH0980348A - Optical scanning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image of high definition without causing variation in the linear speed of moving a light beam or expansion of aberrations by providing an image formation optical system with optical characteristics of right-left symmetry about a main scanning direction, and aligning the center line of the deflection angle of the scanning direction of the light beam with the center of symmetry of the image formation optical system. SOLUTION: An image forming lens 12 images a laser beam deflected by a deflector 10 on a photosensitive drum 3, and has F.arecinθcharacteristics so that the scanning line of the laser beam moves on the photosensitive drum 3 at a nearly equal speed in the main scanning direction. And, the light beam reflected by an optical deflecting element 9 needs to have a position of incidence on an F.arecinθ lens properly adjusted, namely, an adjustment part 20 is provided which adjusts the center line of the light deflection angle of scanning within an effective range of image information to a position on the symmetrical surface of an image forming element. Consequently, an image of good quality is obtained and the permissible range of the precision of the deflection angular speed that the deflector 10 needs to have can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic recording apparatus for printing out a coded signal sent from an electronic computer at a high speed, and converting a beam such as a laser beam into a signal from the electronic computer. The present invention relates to an optical scanning device that controls deflection and modulation according to the above.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic recording device has been used as a recording device for recording image information from an electronic computer.

A conventional optical scanning device used in such a recording apparatus will be described below with reference to FIG.

FIG. 6 is a plan view showing a conventional optical scanning device 71.

The casing 78 is provided with all the members for forming a laser beam necessary for irradiating the photosensitive drum 73 which is a recording medium.

Semiconductor laser 74 and collimator lens 75
And a laser unit 76 as an integrated unit.

The semiconductor laser 74 oscillates a laser beam in the horizontal direction, and the oscillated laser beam enters a collimator lens 75. The laser beam that has passed through the collimator lens 75 becomes a parallel beam that coincides with the optical axis of the collimator lens 75.

The laser beam emitted from the collimator lens 75 is once focused by the cylindrical lens 77 on the reflecting surface of a regular hexahedral polygon mirror 72 having six reflecting surfaces only in the rotation axis direction of the polygon mirror 72. It is incident as if done.

The polygon mirror 72 is mounted on a shaft supported by a highly accurate bearing and driven by a motor (not shown) which rotates at a constant speed. The polygon mirror 72 rotated by the drive of this motor sweeps the laser beam substantially horizontally and deflects it at a constant angular velocity.

The polygon mirror 72 is mainly made of aluminum, and a cutting method is generally used when making it. Further, as the type of motor, a known hysteresis synchronous motor, DC servo motor, etc. may be mentioned. These require a coil winding and a magnetic circuit including an iron plate to be formed in the motor because a rotational force is obtained by a magnetic driving force, and therefore the volume thereof is relatively large.

The laser beam which is swept substantially horizontally by the polygon mirror 72 and emitted is imaged as spot light on the photosensitive drum 73 by an imaging lens 79 having an fθ characteristic.

Further, the laser beam swept by the polygon mirror 72 is guided to the beam detector unit 80 within a range that does not interfere with the image area. The beam detector unit 80 includes one reflecting mirror 81, a slit plate 82 having a small entrance slit, and a photoelectric conversion element substrate 83 having a high response speed. When the position of the laser beam swept by the photoelectric conversion element substrate 83 is detected, the start timing of the input signal to the semiconductor laser 74 for giving the optical information according to the image data on the photosensitive drum 73 by the detection signal is set. Have control.

The laser beam modulated according to the image signal as described above is applied to the photosensitive drum 73, visualized by a known electrophotographic process, and then transferred and fixed on a transfer material such as plain paper to form a hard copy. Is output as.

Further, Japanese Examined Patent Publication No. 60-57052, Japanese Examined Patent Publication No. 60-57053, Japanese Utility Model Publication No. 2-19783, Japanese Utility Model Publication No. 2-19784, Japanese Utility Model Publication No. 2-197.
There is also proposed an optical scanning device having an optical deflection element formed by forming a reflecting mirror for reflecting a laser beam on the surface of a mechanical oscillator using a quartz substrate as described in Japanese Patent Publication No. 85.

The optical scanning devices described in these publications deflect and scan the light beam incident on the reflecting mirror by sinusoidally reciprocally vibrating the deflecting surface (reflecting mirror surface) of the optical deflecting element. The frequency of this reciprocating vibration is called the deflection frequency.

[0016]

However, in the conventional optical scanning device using the polygon mirror, as described above, the aluminum polygon mirror, the hysteresis synchronous motor for driving the polygon mirror, and the D
Since the C servo motor or the like is used, the outer shape and the weight are generally large, and there is a problem that it cannot contribute to the downsizing of a recording apparatus incorporating this optical scanning device.

Further, in the optical scanning device using the optical deflecting element using the conventional mechanical oscillator, since the angular velocity of the deflecting surface of the optical deflecting element differs depending on the deflection angle, the optical deflector including the deflecting surface and the reflected light are reflected. It is necessary to strictly adjust the mounting angle with respect to the image forming optical system for forming an image on the photoconductor. That is, there is a problem in that the deviation of the mounting angle causes a change in the linear velocity of the light beam on the photoconductor and an expansion of the aberration. Therefore, it is necessary to adjust the mounting angle.

The present invention has been made to solve the above-mentioned problems, and by using an optical deflecting element that swings sinusoidally, the external shape and weight can be made smaller than those of the conventional optical scanning device. However, it is possible to prevent the deviation of the mounting angle between the light deflection element and the imaging optical system, and as a result, when such an optical scanning device is used as the image writing means, the linear velocity of the light beam on the medium to be scanned. It is an object of the present invention to provide an optical scanning device capable of obtaining a high-quality image without causing a change in the image quality and an increase in aberration.

[0019]

In order to achieve this object, an optical scanning device according to a first aspect of the present invention provides a light beam emitting means for emitting a light beam, a spring part by an insulating substrate, and a movable part supported by the spring part. Section and a deflecting section provided on the movable section of the scanning section, the optical deflecting section scanning the medium to be scanned with the light beam deflected by the deflecting section, and the light beam on the medium to be scanned. In an optical scanning device including an image forming optical system for forming an image, the image forming optical system has optical characteristics that are bilaterally symmetric with respect to the main scanning direction, and an optical deflection angle of a light deflection angle that effectively scans a range having image information. The center line is located on the plane of symmetry of the imaging element, and the aberration and the linear velocity distribution are even on the left and right.

An optical scanning device according to a second aspect of the present invention is a light beam emitting means for emitting a light beam, a light deflecting means having a sinusoidally oscillating deflecting portion for deflecting the light beam, and the light deflecting means. In an optical scanning device including an image forming optical system for forming an image of the light beam deflected by the means, the image forming optical system has a bilaterally symmetrical shape with respect to the main scanning direction, and effectively outputs image information. The center line of the light deflection angle for scanning the range is located on the plane of symmetry of the image forming element, and the aberration and the linear velocity distribution are even on the left and right.

An optical scanning device according to a third aspect of the present invention is the optical scanning device according to the first or second aspect, in which the center line of the light deflection angle for effectively scanning the range having image information is the imaging element. Adjustment means are provided for making adjustments to position the child on the plane of symmetry.

An optical scanning device according to a fourth aspect is the optical scanning device according to the third aspect, in which the position of the vibration center of the deflecting portion is equal to the stopping reference position of the deflecting portion and the deflecting portion is stationary. Adjust with.

An optical scanning device according to a fifth aspect is the optical scanning device according to the third aspect, wherein a casing that comprehensively supports the optical deflecting means and the image forming optical system, and the optical deflecting means is provided in the casing. For mounting, the light deflecting means and the mounting portion provided on the housing are provided, and the light deflecting means is directly installed on the housing.

An optical scanning device according to a sixth aspect is the optical scanning device according to the fifth aspect, wherein the mounting portion provided on the light deflecting means has a cylinder having a central axis equal to the central axis of vibration of the movable portion. The mounting portion provided on the housing is a cylinder having an inner diameter substantially equal to the outer diameter of the cylindrical portion or the cylindrical portion provided on the mounting portion of the light deflection means. A hole is provided, and the cylindrical portion or the cylindrical portion of the mounting portion provided in the light deflector is fitted into the cylindrical hole of the housing and rotatably mounted.

An optical scanning device according to a seventh aspect is the optical scanning device according to the sixth aspect, wherein the mounting portion provided on the light deflecting means has a circumference with a central axis of vibration of the movable portion as a central axis. An arc-shaped elongated hole whose center line is a part of the circumference is provided on the upper side, and the light deflecting means is fixed to the housing by a screw inserted through the elongated hole.

An optical scanning device according to an eighth aspect is the optical scanning device according to the sixth aspect, wherein the light deflecting means is fixed to the housing with an instant adhesive after the position and the angle are adjusted.

An optical scanning device according to a ninth aspect is the optical scanning device according to the third aspect, wherein a mark indicating a symmetric plane position of the image forming element is provided, and a reference of position and angle adjustment of the optical deflecting means. Becomes

An optical scanning device according to a tenth aspect is the optical scanning device according to the third aspect, in which the mark indicating the symmetric plane position of the image forming element is provided integrally with the housing, and It serves as a reference for position and angle adjustment.

An optical scanning device according to an eleventh aspect is the optical scanning device according to the third aspect, in which the time differential of the electric power for driving the optical deflecting means becomes maximum and the symmetric plane position of the imaging element. Adjustment is performed so that the time points at which the signals from the photoelectric conversion elements installed in the vicinity of are maximum coincide.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing an optical scanning device 1 applied to a laser printer, and the configuration and operation of the optical scanning device of this embodiment will be described in detail with reference to FIG. In addition,
A part of this drawing is a cross-sectional view projected on a plane for explaining the configuration of the present embodiment.

In the housing 2, all members for forming a laser beam necessary for irradiating the photosensitive drum 3 which is the medium to be scanned are arranged.

In a part of the housing 2 hatched in the figure, the semiconductor laser 4, the collimating lens 5, and the lens barrel 7 are provided.
Are integrally fixed to a cylindrical opening 6 which is a part of the housing 2.

The semiconductor laser 4 radiates a laser beam which is modulated in intensity according to an image signal inputted from the outside and makes it enter the collimator lens 5.

The collimator lens 5 is composed of a cylindrical glass lens, and has a function of receiving the laser beam emitted from the semiconductor laser 4 and emitting it as parallel laser light from the opening of the lens barrel 7. As such a cylindrical lens, a GRIN lens having a refractive index distribution in the direction perpendicular to the cylinder axis is known.

The lens barrel 7 is made of a resin molded product and has a function of holding the collimator lens 5 so that the center axis of the outer cylindrical surface of the lens barrel 7 and the optical axis of the collimator lens 5 are substantially aligned with each other.

The semiconductor laser 4 and the collimator lens 5 are
The light emitting point of the semiconductor laser 4 is adjusted to substantially match the optical axis of the collimator lens 5, and the light emitting point of the semiconductor laser 4 is adjusted to match the focus of the collimator lens 5. By adjusting these, the laser beam emitted from the semiconductor laser 4 passes through the collimator lens 5 and becomes a parallel beam that substantially coincides with the optical axis of the collimator lens 5. Due to the opening of the lens barrel 7, the cross-sectional shape of the parallel beam is predetermined. It is emitted after being regulated as much as possible.

The deflector 10 is composed of an optical deflecting element 9 and a drive section 11 for causing the optical deflecting element to sinusoidally vibrate, and is disposed in the housing 2.

Regarding the configuration of the optical deflecting element 9 of this embodiment,
This will be described with reference to FIG.

A movable portion 44 is supported on the frame 41 constituting the light deflection element 9 via spring portions 42 and 43 integrally formed on the upper and lower portions. The frame 41, the spring portions 42 and 43, and the movable portion 44 are composed of a single insulating substrate, and their shapes are formed by using photolithography and etching techniques. Here, the insulating substrate has, for example, a thickness of 5 × 1.
The quartz substrate of about 0 ^-5 m can be used. The frame 41 is not always necessary.

A reflecting mirror 45 and a coil pattern 46 are formed on the movable portion 44 by utilizing the photolithography and etching techniques. The surface precision of the reflecting mirror 45 is set to about 1/4 of the wavelength of the laser beam emitted from the semiconductor laser 4 in order not to disturb the beam shape during image formation. Also, the upper and lower spring parts 4
2 and 43 are provided with lead wires 47 and 48 for conducting to the coil pattern 5, respectively, and a lead wire 47 on the upper side is provided with a jumper wire 49 which is jumped over and connected to the coil pattern 5. There is.

The frame 41 and the spring portion 4 described above are used.
2, 43 and the movable part 44 and the method of forming the reflecting mirror 45 and the coil pattern 46 are described in JP-B-60-.
Since it is described in detail in Japanese Patent No. 57052, description thereof will be omitted here.

A permanent magnet, for example, is used as the drive unit 11 and is arranged so as to form a predetermined bias magnetic field.

The deflector 1 of the present embodiment configured as described above
0, the coil pattern 46 of the light deflection element 9 is set to the drive unit 1.
1 is arranged in the bias magnetic field given by 1 and a current is passed through the coil pattern 46 through the lead wires 47, 48 and the jumper wire 49, so that the movable portion 44 forms a sine wave with the upper and lower spring portions 42, 43 as axes. Reciprocally swings. When the movable portion 44 makes such a swinging motion, the laser beam reflected by the reflecting mirror 45 is deflected and swept horizontally.

The full width of the reciprocating swing of the movable portion 44 is 110 degrees due to the change in the deflection surface angle, but the full width of the light deflection angle for effectively scanning the range having image information is smaller than this, for example, 90. It is set to a certain degree. The vibration frequency is set to about 800 Hz at a resolution of 300 dpi and a printing speed of 6 sheets / minute.

The image forming lens 12 is made of a single plastic lens, forms an image on the photosensitive drum 3 by the laser beam deflected by the deflector 10, and scans the photosensitive drum 3 with the laser beam. It has the F · arcsin θ characteristic so that the line moves in the main scanning direction at a substantially constant speed.

In a general image forming lens, when the incident angle of the light ray on the lens is θ, the position r on the image plane where the image is formed is
There is a relationship of r = f · tan θ (f is the focal length of the imaging lens). However, as in this embodiment, the incident angle of the laser beam reflected by the sinusoidally-deflecting deflector 10 on the imaging lens 12 changes trigonometrically with time.
Therefore, when a general imaging lens is used and the semiconductor laser 4 is turned on at regular time intervals to intermittently emit a laser beam and the beam spot array is imaged on the photosensitive drum 3, those beam spots are formed. The columns are no longer evenly spaced. Therefore, in the optical scanning device 1 using the deflector 10 that sinusoidally swings as in the present embodiment, the imaging lens 12 is used in order to avoid the above-described phenomenon.
The one having the characteristic of r = f · arcsin θ is used as Such an imaging lens 12 is called an F arc sine θ lens.

The light beam reflected by the light deflection element 9 is F
It is necessary to adjust the proper incident position on the arc sine θ lens, and an adjusting unit 20 for adjusting this is provided.

The laser beam emitted from the imaging lens 12 has its optical path folded back by the light guide mirror 13 within a region that does not hinder the irradiation onto the photosensitive drum 3, and is formed as a part of the housing 2. It passes through the knife edge 18 and is guided to the beam detector 14.

The beam detector 14 is composed of a photoelectric conversion element such as a pin photodiode and detects the laser beam to be swept. The beam detector 14 responds to the image signal on the photosensitive drum 3 according to the detection signal indicating this detection. The start timing of the input signal to the semiconductor laser 4 for giving optical information is controlled.

As a result, it is possible to greatly reduce the synchronization deviation of the signal in the horizontal direction due to the unevenness of the deflection angular velocity when the movable portion 44 of the deflector 10 oscillates, a high quality image can be obtained and the polarizer 10 is required. The allowable range of the accuracy of the deflection angular velocity is increased.

The beam detector 14 is arranged on the same plane of the substrate 15 as the semiconductor laser 4. Therefore, the path of the electric signal between the beam detector 14 and the drive circuit for driving the semiconductor laser 4 can be shortened, and the possibility that the circuit system malfunctions due to ambient electric noise is reduced. You can Further, the beam detector 14 and the semiconductor laser 4 are the same one substrate 1.
It is arranged on five planes, and the drive circuits for both are arranged on the substrate 15.
Since they coexist on the above, the number of boards 15 can be reduced, and the number of harnesses 16 connecting the boards can be reduced at the same time.

The substrate 15 is fixed to the housing 2 with screws 60, and the semiconductor laser 4 is pulled out from the housing 2 by the force applied to the substrate by the harness 16 or by a direct external force. It has the effect of preventing misalignment.

The knife edge 18 is provided as a part of the housing 2. Heretofore, a rectangular slit-shaped component made by punching a thin metal has been position-adjusted and fixed to the housing 2 with a screw or the like. Therefore, by forming the knife edge 18 as a part of the housing 2 as in this embodiment, it is possible to reduce the number of parts.

Further, the casing 2 is formed of glass fiber-containing polycarbonate which is generally widely used, and it is necessary that each component is carried with high positional accuracy and distortion due to vibration is small.

The laser beam emitted from the imaging lens 12 after being deflected as described above has its optical path folded back by the Orikaesi mirror group 19 within the irradiation area onto the photosensitive drum 3, and is a part of the housing 2. It is emitted from the window 17 to the outside of the housing 2, is irradiated onto the photosensitive drum 3, and is visualized by a known electrophotographic process or the like, and then is transferred onto a transfer material made of plain paper or special paper by a transfer mechanism and a fixing mechanism (not shown). It is transferred / fixed and output as a hard copy.

Next, the optical scanning device 1 thus constructed
The effect brought by will be described in detail with reference to FIGS. 1 to 5.

In the system using the sinusoidally deflecting deflector 10 as in the optical scanning device 1 according to the present invention as shown in FIG. 1, the angular velocity of the surface of the reflecting mirror 45 provided in the optical deflecting element 9 is increased. Is different depending on the deflection angle, the mounting angle formed by the light deflection element 9 including the reflection mirror 45 and the imaging lens 12 that forms an image of the reflected light beam on the reflection mirror 45 on the photosensitive drum 3 is strictly adjusted, and It is necessary to adjust the light beam reflected by the deflecting element 9 so as to be incident on the imaging lens 12 at an appropriate incident position and incident angle according to the deflection angle at the time of the reflection.

Here, the necessity of adjusting the angle of the light deflection element 9 will be described with reference to FIG. FIG. 3 shows that the light beam scanned by the light deflecting element 9 is incident on the F arc sine θ lens having an optical characteristic that is bilaterally symmetrical in the main scanning direction as the imaging lens 12 used in this embodiment. The aberration when the image is formed on the photosensitive drum 3 by the sine θ lens is shown. Then, the center line of the deflection angle scanned by the light beam corresponding to the effective image information is the F arc sine θ
When the lens is located on the center of symmetry of the lens, distortion and field curvature and other aberrations are distributed equally to the left and right, and the overall aberration can be reduced. However, when the center line of the deflection angle deviates from the center of symmetry of the F arc sine θ lens, either the left or right aberration increases, and the overall aberration increases. Further, since the change in the angular velocity of the deflected beam light when entering the F arcsine θ lens is symmetrical with respect to the center line of the shake angle, the center line of the shake angle is the center of symmetry of the F arcsine θ lens. If not present, the linear velocity distribution of the light beam scanning the photosensitive drum 3 will be different between left and right, which is disadvantageous to the design in which the linear velocity is kept within an allowable range.

From the above description, the center line of the deflection angle scanned by the light beam corresponding to the effective image information is on the symmetric center of the imaging lens 12 having bilateral optical characteristics such as the F arc sine θ lens. It is clear that the aberration can be minimized and the change in the linear velocity of the light beam can be reduced by setting the position to be located at. Therefore,
It is extremely important to adjust the mounting positions of the deflector 10 and the imaging lens 12 so that the center line of the shake angle is located on the symmetrical center of the F arc sine θ lens.

Next, a configuration and an adjusting method for adjusting the positions of the deflector 10 and the imaging lens 12 will be described with reference to FIGS. FIG. 4 is a view showing a cross section of the adjusting unit 20 for adjusting the angle of the deflector 10. The adjusting unit 20 has a cylindrical mounting portion 30 provided integrally with the deflector 10 and an outer diameter of the cylindrical mounting portion 30 with the oscillation axis of the optical deflecting element 9 indicated by the alternate long and short dash line as the central axis. The cylindrical mounting portion 30 of the deflector 10 has the same inner diameter and is formed in the housing 2, and the cylindrical mounting portion 30 of the deflector 10 can be fitted in the cylindrical hole 31 and is rotatably mounted. There is. In addition, the mounting portion 30 is the vibration shaft 2 described above.
An arcuate elongated hole 32 having a part of the circumference as the center line is provided on the circumference centered on 2. Therefore, the deflector 10
Through the arc-shaped elongated hole 32 formed in the mounting portion 30 with respect to the screw hole 33 provided in the housing 2.
It is fixed by screws.

A mark 35 for aligning the position of the center of symmetry of the imaging lens 12 is provided near the position where the imaging lens 12 of the housing 2 is attached. The mark 35 may be added to the housing 2 by printing, cutting or the like, or may be integrally formed at the time of molding the housing 2. The method of integrally manufacturing the casing 2 at the time of molding has an advantage that the process and material costs can be reduced. The mark 35 is provided at a position where the center of symmetry of the image forming lens 12 should be located. When the optical scanning device 1 is assembled, the center of symmetry of the image forming lens 12 is aligned with the mark 35 and the casing 2 is formed. Attach to.

When adjusting the position of the center line of the deflection angle of the light beam reflected by the reflecting mirror 45 of the deflector 10, semiconductor photoelectric conversion such as a photodiode (not shown) is provided at the position of the mark 35 provided on the housing 2. An element is installed and it is detected that the center of the deflection angle when the light beam is scanned is on the mark 35 indicating the center of symmetry of the imaging lens 12.

The detection method will be described. Deflector 1
0 resonates when electric power having a frequency near the natural frequency of the optical deflecting element 9 is applied, and sinusoidal vibration is generated around the spring portions 42 and 43. Therefore, if the time change of the applied electric power is monitored, The time when the light deflecting element 9 passes the center position of vibration can be detected. This is equal to the time when the derivative of power with respect to time is greatest.

Here, FIG. 5 shows an outline of the time change of the electric power supplied to the deflector 10 and the change of the signal output from the photodiode. As shown in FIG. 5, when the time A at which the time change of the electric power is maximum coincides with the time B at which the signal output from the photodiode is maximum, the symmetry center of the imaging lens 12 should be located on the line. In addition, it can be said that the center line of the deflection angle of the light beam reflected by the reflecting mirror 45 of the light deflection element 9 is adjusted to be positioned. Therefore, while monitoring the signal output from the photodiode and the drive power applied to the deflector 10, by rotating the mounting portion 30 supporting the deflector 10 along the cylindrical hole 31 provided in the housing 2, Deflector 10 and its reflecting mirror 4
Rotate 5 Then, at the angle at which the time point A at which the signal output from the photodiode becomes maximum and the time point B at which the differential of the drive power applied to the deflector 10 becomes maximum coincide with each other, the screw 34 is used to screw the deflector 10 in place. And the attachment part 30 is completely fixed to the housing 2. By the above work, the attachment angle of the deflector 10 could be easily adjusted.

At this time, the long hole 3 provided in the deflector 10
Reference numeral 2 denotes an arcuate hole provided on the circumference centered on the vibration axis with a part of the circumference as the center line. Therefore, when the deflector 10 is rotatable about the vibration axis, the adjustment position It is possible to screw to the housing 2 through the elongated hole 32 in the state where is determined. Note that the same effect can be obtained by providing the housing 2 with the same elongated hole 32 and providing the mounting hole 30 with the screw hole.

Further, when the center position of the reciprocating swing of the light deflecting element 9 is equal to the standard stationary position, that is, the position of the light beam reflected by the reflecting mirror 45 when the light deflecting element 9 is stationary, the above-mentioned adjustment is performed. It gets even easier. That is, with the light deflection element 9 stationary at the standard stationary position, the light beam emitted from the semiconductor laser 4 is reflected and made incident on the photodiode arranged in the same manner as described above. Then, while monitoring the signal output from the photodiode, the mounting portion 30 mounted on the deflector 10 is rotated along the cylindrical hole 31 provided in the housing 2 to maximize the signal output from the photodiode. At this position, the screw 34 is screwed to fix the deflector 10 and the mounting portion 30 to the housing 2 completely. With the above work, the work of aligning the center line of the deflection angle with the center of symmetry of the imaging lens 12 can be performed more easily.

The means for fixing the deflector 10 to the housing 2 is not limited to screwing, but the same effect can be obtained by using an instant adhesive. However, it can be easily fixed.

According to the embodiment described in detail above, in the optical scanning device using the sine-oscillating deflector 10, the aberration caused by the angular deviation between the deflector 10 and the imaging lens 12 is enlarged and the deflector 10 is used. It is possible to prevent the change in the linear velocity of the light beam scanned by the laser beam from increasing by making a simple adjustment.

Next, the operation of the optical scanning device 1 configured as described above will be described with reference to FIG.

The semiconductor laser 4 emits a laser beam by blinking based on an image signal. The laser beam is collimated by the collimating lens 5 and then emitted by being subjected to a shaping action by the opening of the lens barrel 7. It The laser beam is incident on the reflecting mirror 45 formed on the light deflection element 9 of the deflector 10. Since the movable portion 44 of the light deflecting element 9 is sinusoidally swung by the driving portion 11, the laser beam reflected by the reflecting mirror 45 is sinusoidally reciprocally deflected. The laser beam deflected by the light deflection element 9 is further converged by the F arc sine θ lens as the imaging lens 12 so as to be imaged on the photosensitive drum 3. At the same time, the laser beam deflected by the optical deflector 9 is subjected to an optical path refracting action such that the photosensitive drum 3 is scanned at a constant speed.

The laser beam converged by the image forming lens 12 has its optical path folded by the Orikaishi mirror 6 and forms an image on the photosensitive drum 3, and is sequentially scanned at a constant speed.
The emitted laser beam is refracted by the light guide mirror 13 outside the image scanning range and guided to the beam detector 14. When the beam detector 14 detects the laser beam,
The detection signal is output. This detection signal is used as a horizontal synchronizing signal and is used to obtain the reference position of the image in the horizontal direction.

Then, the photosensitive drum 3 which has been subjected to the optical scanning action based on the image information is visualized by a known electrophotographic process or the like, and then, a known transfer mechanism and fixing mechanism are formed on a transfer material made of plain paper or special paper. Is transferred and fixed by and is output as a hard copy.

The present invention is not limited to the above-described embodiments, but can be modified as appropriate.

For example, in this embodiment, the mounting portion 3
Although 0 has a cylindrical shape, it may have a cylindrical shape, and a cylindrical shape or a part of a cylindrical shape may be used. Further, the same angle adjustment can be performed only by combining the elongated hole 32 and the screw hole 33 without providing the mounting portion 30. Also,
A long hole may be provided on the housing side and combined with a screw hole on the deflector side for position adjustment and fixing. Furthermore, instead of the elongated hole, a slightly larger round hole may be formed in the screw hole 33, and the play may be used to adjust the angle.

In addition, various modifications can be made without departing from the spirit of the present invention.

[0077]

As is apparent from the above description,
The optical scanning device according to claim 1 comprises an insulating substrate, a spring portion, and
Since the movable portion supported by the spring portion is constituted and the light deflecting means having the deflecting portion for deflecting the light beam is used in the movable portion, the outer diameter shape as compared with the conventional optical scanning device, The weight can be reduced, which greatly contributes to downsizing of the device. Furthermore, the imaging optical system has optical characteristics that are bilaterally symmetric with respect to the main scanning direction, and the center line of the deflection angle of the light beam scanning the range corresponding to effective image information is on the symmetric center of the imaging optical system. By setting the position to be located at, it is possible to evenly distribute the aberrations to the left and right, and it is possible to reduce the overall aberrations. Further, since the linear velocity distribution of the scanned light beam becomes bilaterally symmetric by the above setting, the linear velocity change of the light beam within one scanning can be set small. Therefore, the accuracy of the image recorded on the medium to be scanned can be improved.

Since the optical scanning device of the second aspect uses the optical deflecting means provided with the sinusoidally oscillating deflecting portion for deflecting the light beam, it has an outer diameter shape and a weight greater than those of the conventional optical scanning device. Both can be made smaller, which greatly contributes to downsizing of the device. Further, the imaging optical system has optical characteristics that are bilaterally symmetric with respect to the main scanning direction, and the center line of the deflection angle of the light beam scanning the range corresponding to effective image information is on the symmetric center of the imaging optical system. By setting the position to be located at, it is possible to evenly distribute the aberrations to the left and right, and it is possible to reduce the overall aberrations. Further, since the linear velocity distribution of the scanned light beam becomes bilaterally symmetric by the above setting, the linear velocity change of the light beam within one scanning can be set small. Therefore, the accuracy of the image recorded on the medium to be scanned can be improved.

An optical scanning device according to a third aspect of the present invention comprises an adjusting means for adjusting the center line of the deflection angle of the light beam scanned by the light deflecting means so as to be located on the center of symmetry of the imaging optical system. This facilitates the optical deflecting means and the imaging optical system so that the center line of the deflection angle of the light beam scanning the range corresponding to the effective image information and the center of symmetry of the imaging optical system coincide with each other. It becomes possible to set and arrange.

According to another aspect of the optical scanning device of the present invention, the center position of vibration of the deflecting portion is set equal to the standard stationary position of the deflecting portion, so that the optical deflecting means of the optical deflecting means can be operated even when the deflecting portion is stationary. The position can be adjusted extremely easily.

According to the optical scanning device of the fifth aspect, by providing a housing that comprehensively supports the light deflecting means and the imaging optical system, and mounting portions provided in the light deflecting means and the housing, respectively, Instead of attaching the deflection means directly to the housing,
Since the light deflection means is attached via the attachment portion, it is possible to easily adjust the light deflection means when attaching the light deflection means to the housing.

According to another aspect of the optical scanning device of the present invention, the mounting portion provided on the optical deflecting means is provided with a cylindrical portion or a cylindrical portion having a central axis equal to the central axis of vibration of the movable portion, and the housing is provided in the housing. Since the mounting portion provided has a cylindrical hole having an inner diameter substantially equal to the outer diameter of the cylindrical portion or the cylindrical portion, it can be rotatably mounted when mounting the light deflection means to the housing. As a result, it is possible to further facilitate the angle adjustment of the light deflecting means.

According to a seventh aspect of the present invention, in the optical scanning device, the mounting portion provided in the light deflecting means has a circle centered at a point on the center axis of vibration of the movable section and on a circle perpendicular to the center axis. Since the arc-shaped elongated hole having a part of the circumference as the center line is provided, it is possible to fix the light deflecting means to the housing at an appropriate angle after adjusting the light deflecting means in a rotatable state.

In the optical scanning device according to the eighth aspect, since the light deflecting means is fixed to the housing by the instant adhesive, the work for fixing the light deflecting means to the housing at an appropriate angle after the adjustment is performed in a freely rotatable state. Will be easier.

In the optical scanning device of the ninth aspect, the image forming optical system is constituted, and the optical element having the optical characteristic which is bilaterally symmetric with respect to the main scanning direction is provided with a mark indicating the position of the center of symmetry. Therefore, it is possible to easily confirm the position of the center of symmetry of the imaging element.

In the optical scanning device of the tenth aspect, since the mark corresponding to the mark indicating the position of the center of symmetry of the imaging element is provided integrally with the housing, the symmetric position can be achieved without increasing the number of parts. Can be easily confirmed, and the mounting accuracy when mounting the imaging element in the housing is improved.

An optical scanning device according to an eleventh aspect of the present invention is installed near the time point when the time derivative of the electric power for driving the optical deflecting means becomes maximum and the symmetrical center position of the imaging optical system, and detects the light beam. Since the time when the signal from the photoelectric conversion element becomes maximum is made to coincide, the angle of the light deflecting means can be easily adjusted with high accuracy.

[Brief description of drawings]

FIG. 1 is a plan view of an optical scanning device.

FIG. 2 is a perspective view of an optical deflection element used in the optical scanning device.

FIG. 3 is a diagram illustrating aberration of the optical scanning device.

FIG. 4 is a cross-sectional view of the optical scanning device.

FIG. 5 is a diagram illustrating a method of adjusting the optical scanning device.

FIG. 6 is a plan view of a conventional optical scanning device.

[Explanation of symbols]

 1 Optical Scanning Device 2 Housing 3 Photosensitive Drum 4 Semiconductor Laser 9 Optical Deflection Element 12 F Arcsine θ Lens 20 Adjusting Section 30 Mounting Section 32 Oblong Hole 35 Mark

Claims (11)

[Claims] 1. A light beam emitting means for emitting a light beam, a spring portion by an insulating substrate, a movable portion supported by the spring portion, and a deflection portion provided in the movable portion,
An optical deflecting unit that scans the medium to be scanned with a light beam that is deflected by the deflection unit swinging, and an imaging optical system for forming an image of the light beam on the medium to be scanned are provided. In the optical scanning device, the imaging optical system has optical characteristics that are bilaterally symmetric with respect to the main scanning direction, and the deflection angle in the scanning direction of the light beam that scans a range corresponding to effective image information by the light deflecting unit. An optical scanning device, wherein a center line and a center of symmetry of the image forming optical system coincide with each other. 2. A light beam emitting means for emitting a light beam, and a deflecting portion that swings sinusoidally for deflecting the light beam, wherein the light deflected by the deflecting portion is deflected. In an optical scanning device comprising a light deflecting means for scanning a medium to be scanned with a beam, and an image forming optical system for forming an image of the light beam on the medium to be scanned, the image forming optical system is provided in the main scanning direction. The center line of the deflection angle in the scanning direction of the light beam, which has a bilaterally symmetric optical characteristic and scans a range corresponding to effective image information by the light deflector, and the center of symmetry of the imaging optical system are Optical scanning device characterized by 3. The light deflecting means or the image forming optical system in order to match a center line of the deflection angle of the light beam scanned by the light deflecting means with the symmetrical center of the image forming optical system. The optical scanning device according to claim 1 or 2, further comprising an adjusting unit for adjusting the position of at least one of the positions. 4. The optical scanning device according to claim 3, wherein a central position of vibration of the deflecting unit is equal to a standard stationary position of the deflecting unit. 5. A housing that comprehensively supports the light deflecting means and the imaging optical system, and the light deflecting means and the housing are provided to attach the light deflecting means to the housing, respectively. The optical scanning device according to claim 3, further comprising: 6. The mounting portion provided in the light deflector comprises a cylindrical portion or a columnar portion having a central axis equal to the central axis of vibration of the movable portion of the light deflector, and the mounting portion is provided in the housing. 6. The mounting portion provided is provided with a cylindrical hole having an inner diameter substantially equal to an outer diameter of the cylindrical portion or the cylindrical portion provided on the mounting portion of the light deflecting means. The optical scanning device according to. 7. The mounting portion provided in the light deflecting means has a point on a center axis of vibration of the movable portion of the light deflecting element as a center and on a circumference perpendicular to the center axis, The optical scanning device according to claim 5, further comprising an arc-shaped elongated hole whose center line is a part of the circumference. 8. The optical scanning device according to claim 3, wherein the light deflector is fixed to the housing with an instant adhesive. 9. An image-forming element that constitutes the image-forming optical system and has bilaterally symmetric optical characteristics with respect to the main scanning direction is provided with a mark that indicates the position of the center of symmetry. The optical scanning device according to claim 3. 10. The optical scanning device according to claim 9, wherein a mark corresponding to the mark indicating the position of the center of symmetry of the image forming element is provided integrally with the housing. 11. The time point at which the time derivative of the electric power for driving the light deflecting means becomes maximum in order to adjust the position of at least one of the light deflecting means or the imaging optical system by the adjusting means. And a time point at which a signal from a photoelectric conversion element for detecting the light beam is maximized, which is installed near a position of the center of symmetry of the imaging optical system. Optical scanning device.