JP3785668B2 - Optical scanning device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a recording apparatus of an electrophotographic system that prints out a coded signal sent from an electronic computer at a high speed, and deflects and modulates a beam such as a laser beam in accordance with a signal from the electronic computer or the like. The present invention relates to an optical scanning device.
[0002]
[Prior art]
Conventionally, an electrophotographic recording apparatus is used as a recording apparatus for recording image information from an electronic computer.
[0003]
Hereinafter, a conventional optical scanning device used in such a recording apparatus will be described with reference to FIG.
[0004]
FIG. 5 is a plan view showing a conventional optical scanning device 70.
[0005]
In the casing 71, all members for forming a laser beam necessary for irradiating the photosensitive drum 73 as a recording medium are arranged.
[0006]
The semiconductor laser 74 and the collimator lens 75 constitute a laser unit 76 as an integral unit.
[0007]
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.
[0008]
The laser beam emitted from the collimator lens 75 is once focused by the cylindrical lens 77 on the reflection surface of a regular hexahedral polygon mirror 72 having six reflection surfaces only in the direction of the rotation axis of the polygon mirror 72. Is incident.
[0009]
The polygon mirror 72 is mounted on a shaft supported by a high-precision bearing and is driven by a motor 78 that rotates at a constant speed. By the polygon mirror 72 rotated by the driving of the motor, the laser beam is swept almost horizontally and deflected at an equal angular velocity.
[0010]
The polygon mirror 72 is mainly formed of aluminum as a material, and a cutting method is generally used for its production. Examples of the motor 78 include a known hysteresis synchronous motor and a DC servo motor. Since the rotational force is obtained by the magnetic driving force, it is necessary to form a coil winding and a magnetic circuit including an iron plate in the motor, and the volume thereof is relatively large.
[0011]
The laser beam swept and emitted almost horizontally by the polygon mirror 72 is imaged as spot light on the photosensitive drum 73 by an imaging lens 79 having fθ characteristics.
[0012]
Further, the laser beam swept by the polygon mirror 72 is guided to a beam detector unit 80 provided at a position 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 incident slit, and a photoelectric conversion element substrate 83 having a high response speed. The photoelectric conversion element substrate 83 outputs a detection signal when detecting the swept laser beam. By this detection signal, the start timing of the input signal to the semiconductor laser 74 for giving optical information corresponding to the image data on the photosensitive drum 73 is controlled.
[0013]
The laser beam scanned as described above is irradiated onto the photosensitive drum 73, visualized by a known electrophotographic process, transferred onto a transfer material such as plain paper, and output as a hard copy.
[0014]
Further, as described in JP-B-60-57052, JP-B-60-57053, JP-B-2-19783, JP-B-2-19784, JP-B-2-19785 There has also been proposed an optical scanning device having an optical deflection element in which a reflecting mirror for reflecting a laser beam is formed on the surface of a mechanical vibrator using a substrate.
[0015]
The optical scanning devices described in these publications deflect and scan the light beam incident on the reflecting mirror by causing the deflecting surface (reflecting mirror surface) of the optical deflecting element to reciprocally oscillate sinusoidally. The frequency of this reciprocating vibration is referred to as a deflection frequency.
[0016]
[Problems to be solved by the invention]
However, as described above, the conventional optical scanning apparatus using a polygon mirror uses an aluminum polygon mirror, a hysteresis synchronous motor, a DC servo motor, and the like for driving the aluminum mirror. In general, both the shape and the weight increase, and there is a problem that it cannot contribute to the downsizing of the recording apparatus incorporating the optical scanning device.
[0017]
On the other hand, in a conventional optical scanning device using an optical deflection element that uses a mechanical vibrator, when optical deflection elements are mass-produced, variations in deflection frequencies of individual optical deflection elements become large. Accordingly, since the deflection angular velocity of the light beam deflected by the light deflecting element has a large individual difference depending on each light deflecting element, the optical scanning device using such a light deflecting element records an image. The position of the image output according to the designed deflection angular velocity and the position of the image output according to the deflection angular velocity of the actual optical deflection element will be different, and the original image will be accurately reproduced. There was a problem that could not.
[0018]
The present invention has been made to solve the various problems described above, and by using a deflecting portion that vibrates sinusoidally, the outer shape and weight of the conventional optical scanning device are smaller, and further, An optical scanning device that compensates for variations in the deflection frequency of the deflecting unit that vibrates sinusoidally and does not cause positional deviation of the output image when such an optical scanning device is used as image writing means. The purpose is to provide.
[0019]
[Means for Solving the Problems]
In order to achieve this object, an optical scanning device according to claim 1 comprises:
A light beam emitting means for emitting a light beam;
A scanning unit is composed of a spring unit, a movable unit supported by the spring unit and vibrating in a sinusoidal manner, and a deflecting unit provided on the movable unit, and scans a scanned medium with a light beam deflected by the deflecting unit. In an optical scanning device comprising an optical deflection means,
Modulation clock generating means for generating a modulation clock for determining the blinking timing of the light beam emitting means according to image data;
Corresponds to the solid variation of the deflection frequency of the reciprocating vibration of the movable part value Operating means operable to input
Modulation frequency control means for variably controlling the frequency of the modulation clock provided by the modulation clock generation means in accordance with an input from the operation means,
The light deflection means is classified into a plurality of according to the deviation amount from the reference value of the deflection frequency of the movable part with a predetermined width that can satisfy the standard value of the positional deviation of the output image, and the operation means Corresponding to the classification value When the frequency of the modulation clock is changed, the image writing width of the light beam scanned on the scanned medium changes with a certain number of pixels, and the movable part of the light deflecting means It is possible to compensate for individual variations in the deflection frequency.
[0020]
According to a second aspect of the present invention, the optical scanning device according to the first aspect corresponds to the classification of the optical deflection means. value The optical scanning device assembler can actuate the modulation frequency adjusting means to set the modulation frequency in accordance with the display information on the display means.
[0021]
According to a third aspect of the present invention, in the optical scanning device of the first aspect, the spring portion, the movable portion, and the deflecting portion are integrally formed on an insulating substrate. Due to the torsional recovery force in the longitudinal direction, the movable portion vibrates sinusoidally, and with this configuration, a small light deflection unit can be realized.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.
[0023]
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 the present embodiment will be described in detail with reference to FIG. A part is a sectional view projected onto a plane in order to explain the configuration of the present embodiment.
[0024]
In the housing 2, all members for forming a laser beam necessary for irradiating the photosensitive drum 3, which is a scanned medium, are arranged.
[0025]
In a part of the housing 2 that is hatched in the figure, the semiconductor laser 4, the collimating lens 5, and the lens barrel 7 are integrally fixed to a cylindrical opening 6 that is a part of the housing 2.
[0026]
The semiconductor laser 4 emits a laser beam that is strongly or weakly modulated in accordance with image information to be written and enters the collimating lens 5.
[0027]
The image information is supplied from the outside of the optical scanning device 1 by an image data output device 23 configured by a line buffer or the like.
[0028]
The LD drive circuit 26 includes a constant current circuit, a current mirror circuit, and the like, and controls on / off of a current value flowing through the semiconductor laser 4.
[0029]
The modulator 25 has a function of modulating an image data signal in accordance with image information of the image data supply unit 23 at each ON / OFF timing of the modulation clock generated by the modulation clock generator 24 and sending this signal to the LD drive circuit 26. .
[0030]
The modulation clock generator 24 comprises a circuit such as a voltage controlled oscillator (VCO), and the frequency of the modulation clock generated can be variably controlled by an external input.
[0031]
The modulation clock controller 16 includes a reference voltage generation circuit and the like, and generates a certain DC voltage by an external input.
[0032]
The operation panel 15 is an input device of a laser printer (not shown) provided outside the optical scanning device 1.
[0033]
As will be described later, when a value corresponding to the deflection frequency of the polarizer 10 is input from the operation panel 15, the modulation clock controller 16 receives this value and generates a constant DC voltage corresponding to the value. The subsequent modulation clock generator 24 generates a modulation clock having a frequency corresponding to the DC voltage value. Each time the modulation clock is turned on / off, the modulator 25 modulates the image data signal and sends this signal to the LD drive circuit 26.
[0034]
The collimating lens 5 is made of a cylindrical glass lens, and receives the laser beam emitted from the semiconductor laser 4 and emits 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 a direction perpendicular to the cylindrical axis is known.
[0035]
The lens barrel 7 is made of a resin molded product, and has a function of holding the collimating lens 5 so that the central axis of the outer cylindrical surface of the lens barrel 7 and the optical axis of the collimating lens 5 substantially coincide with each other.
[0036]
The semiconductor laser 4 and the collimating lens 5 are adjusted so that the light emitting point of the semiconductor laser 4 substantially coincides with the optical axis of the collimating lens 5 and the light emitting point of the semiconductor laser 4 coincides with the focal point of the collimating lens 5. By adjusting these, the laser beam emitted from the semiconductor laser 4 passes through the collimating lens 5 and then becomes a parallel beam substantially coincident with the optical axis of the collimating lens 5, and the cross-sectional shape of the parallel beam is predetermined by the opening of the lens barrel 7. The shape is regulated as much as possible and emitted.
[0037]
The deflector 10 includes an optical deflection element 9 and a drive unit 11 for causing the optical deflection element to sine vibrate, and is disposed in the housing 2.
[0038]
The configuration of the optical deflection element 9 of this embodiment will be described with reference to FIG.
[0039]
A movable portion 44 is supported on a frame 41 constituting the light deflection element 9 via spring portions 42 and 43 integrally formed at the upper and lower portions. The frame 41, the spring portions 42 and 43, and the movable portion 44 are constituted by a single insulating substrate, and their shapes are formed by using photolithography and etching techniques. Here, as the insulating substrate, for example, a quartz substrate having a thickness of about 50 microns can be used. The frame 41 is not always necessary.
[0040]
Further, a reflecting mirror 45 and a coil pattern 46 are formed on the movable portion 44 by using photolithography and etching techniques. The surface accuracy of the reflecting mirror 45 is set to about a quarter of the wavelength of the laser beam emitted from the semiconductor laser 4 so as not to disturb the beam shape at the time of image formation. The upper and lower spring portions 42 and 43 are provided with lead wires 47 and 48 for conduction to the coil pattern 46, respectively. A jumper wire 49 is provided.
[0041]
The method for forming the frame 41, the spring portions 42 and 43 and the movable portion 44 and the method for forming the reflecting mirror 45 and the coil pattern 46 are described in detail in Japanese Patent Publication No. 60-57052. The description in is omitted.
[0042]
For example, a permanent magnet is used as the drive unit 11 and is arranged so as to form a predetermined bias magnetic field.
[0043]
In the deflector 10 of this embodiment configured as described above, the coil pattern 46 of the optical deflection element 9 is arranged in the bias magnetic field given by the drive unit 11, and the coil is connected via the lead wires 47 and 48 and the jumper wire 49. By passing an electric current through the pattern 46, the movable portion 44 reciprocally swings around the upper and lower spring portions 42 and 43 as axes. As the movable portion 44 performs such a swinging motion, the laser beam reflected by the reflecting mirror 45 is deflected and swept horizontally. Note that the full angle of the reciprocating swing of the movable portion 44 is 110 degrees due to the change in the angle of the deflected laser beam.
[0044]
The imaging lens 12 is made of a single plastic lens, forms an image on the photosensitive drum 3 with the laser beam subjected to the deflection action by the deflector 10, and further scan lines by the laser beam are substantially on the photosensitive drum 3. It has F · arcsin θ characteristics so as to move in the main scanning direction at a constant speed.
[0045]
In a general imaging lens, when the incident angle of a light beam to the lens is θ, there is a relationship of r = f · tan θ (f is a focal length of the imaging lens) with respect to a position r where an image is formed on the image plane. is there. However, the incident angle of the laser beam reflected by the sinusoidal deflector 10 with respect to the imaging lens 12 changes in a trigonometric manner with time. Accordingly, when a general imaging lens is used and the laser beam is intermittently emitted by turning on and off the semiconductor laser 4 at regular time intervals, and the beam spot array is imaged on the photosensitive drum 3, these beam spots are obtained. The spacing between rows will not be equal. Therefore, in the optical scanning device 1 using the deflector 10 that swings sinusoidally, an imaging lens 12 having a characteristic of r = f · arcsin θ is used as the imaging lens 12 in order to avoid the above-described phenomenon. Such an imaging lens 12 is referred to as an F arc sine θ lens.
[0046]
Then, the laser beam emitted from the imaging lens 12 has its optical path turned back by the light guide mirror 13 in a region that does not hinder irradiation on the photosensitive drum 3, and the knife edge 18 formed as a part of the housing 2. And is guided to the beam detector 14.
[0047]
The beam detector 14 is composed of a photoelectric conversion element such as a pin photodiode, and detects a swept laser beam. Optical information corresponding to an image signal is received on the photosensitive drum 3 in accordance with a detection signal indicating this detection. The start timing of the input signal to the semiconductor laser 4 for giving is controlled.
[0048]
As a result, the signal misalignment in the horizontal direction due to unevenness of the deflection angular velocity when the movable portion 44 of the deflector 10 swings can be greatly reduced, and a high-quality image can be obtained and the deflection angular velocity required for the polarizer 10 can be obtained. The tolerance of accuracy is increased.
[0049]
The knife edge 18 is provided as a part of the housing 2. Conventionally, a rectangular slit-shaped part obtained by punching a thin metal has been positioned and fixed to the housing 2 with screws or the like. Therefore, by forming the knife edge 18 as a part of the housing 2, an effect that the number of parts can be reduced is obtained.
[0050]
Further, the casing 2 is formed of a polycarbonate containing glass fiber, which is widely used, and it is necessary that each component is supported with high positional accuracy and distortion due to vibration is small.
[0051]
The laser beam deflected as described above and emitted from the imaging lens 12 is folded back in the optical path by the folding mirror group 6 within the irradiation area on the photosensitive drum 3, and is opened from the window 17 which is a part of the casing 2. 2 is emitted outside and irradiated onto the photosensitive drum 3 to form a latent image on the photosensitive drum 3. The latent image on the photosensitive drum 3 is visualized by a known electrophotographic process or the like, and then transferred and fixed on a transfer material made of plain paper or special paper by a transfer mechanism and a fixing mechanism (not shown) and output as a hard copy. The
[0052]
The optical deflecting element 9 is formed by processing a single crystal quartz substrate by an etching process and a photolithography process. That is, since the error of the deflection frequency is about ± 3%, the variation of the deflection frequency due to the individual optical deflection elements is large during mass production. This variation in the deflection frequency is caused by the speed at which the laser beam deflected by the optical deflection element travels from the scanning start position 21 to the scanning end position 22 on the photosensitive drum 3, as shown in FIG. Since it appears as variations in angular velocity, the following problems occur.
[0053]
Now, if the semiconductor laser 4 as the light source is modulated according to a fixed clock according to the image information, the image information to be written at the scanning end position 22 according to the above-described variation in the deflection angular velocity for each light deflection element. The position is shifted within a range of ± 3% in the scanning direction, and as a result, the output image is misaligned.
[0054]
This will be specifically described according to numerical examples. When the deviation of the deflection frequency of the optical deflection element is 800 Hz ± 3% and the distance from the scanning start position 21 to the scanning end position 22 is 210 mm (corresponding to an A4 size paper surface), the scanning start position is at a deflection frequency of 800 Hz. Assume that the semiconductor laser 4 is modulated according to a constant clock with a design value that writes image information from 21 to the scanning end position 22 at a resolution of 300 dpi. The reference data number written at this time is 2459 points.
[0055]
At this time, if the deflection frequency inherent to the optical deflection element is 3% higher than 800 Hz, the image information that should be written at the scanning end position 22 is shifted by 6.1 mm in the left direction in FIG. Is written at the position of, and the output image is reduced by 3% overall. On the contrary, if the deflection frequency inherent to the optical deflection element is 3% lower than 800 Hz, the image information that should be written at the scanning end position 22 is at the scanning end position 22b shifted by 6.1 mm in the right direction on the paper surface of FIG. As a result, the output image is enlarged by 3% as a whole. In general, in a laser beam printer, the deviation of the scanning end position 22 on the A4 paper surface is only allowed to be about ± 1.5 mm. Therefore, a configuration in which the deviation of ± 6.1 mm as described above is practical is practical. Absent.
[0056]
In order to solve this problem, the modulation clock generator 24 is used to make the number of data from the scanning start position 21 to the scanning end position 22 on the photosensitive drum 3 constant regardless of the variation in the deflection frequency. A modulation clock controller 16 is provided that can adjust the frequency of the modulation clock generated.
[0057]
That is, in the optical scanning device 1 of the above numerical example, if the deflection frequency of the optical deflection element 9 is 3% higher than the design value, the modulation clock controller 16 similarly increases the frequency of the modulation clock by 3% from the design value. As a result, the number of data from the scanning start position 21 to the scanning end position 22 is the above-described reference value 2459 regardless of variations in the deflection frequency, and is always constant. The frequency setting by the modulation clock controller 16 is based on a setting input from the operation panel 15 outside the optical scanning device.
[0058]
On the contrary, if the deflection frequency of the optical deflection element 9 is 3% lower than the design value, the modulation clock controller 16 similarly lowers the frequency of the modulation clock by 3% from the design value so that the scan start position 21 is changed to the scan end position. The number of data up to 22 is the same as the number of data when the optical deflection element 9 having the deflection frequency as designed is used, and is constant regardless of variations in the deflection frequency.
[0059]
Such adjustment of the data modulation frequency is performed by measuring the speed at which the laser beam travels from the scanning start position 21 to the scanning end position 22 during the manufacturing process of the optical scanning apparatus 1, and the speed is set to the deflection frequency according to the reference design value. This is realized by a relatively simple process of calculating how many percent of the laser beam velocity is higher or lower than the speed of the laser beam when the optical deflection element 9 is used and inputting this numerical value from the operation panel 15.
[0060]
In addition, since such a variation in the deflection frequency causes a positional deviation of the image in the direction orthogonal to the scanning direction, the rotational speed of the photosensitive drum 3 is also different from the deviation amount from the design value of the deflection frequency. Adjustments must be made at an equivalent ratio.
[0061]
That is, in the optical scanning device 1 of the above numerical example, if the deflection frequency of the optical deflection element 9 is 3% higher than the design value, the rotational speed of the photosensitive drum 3 is similarly adjusted to be 3% higher than the design value, thereby recording medium There is no image misalignment on the paper.
[0062]
On the contrary, if the deflection frequency of the light deflection element 9 is 3% lower than the design value, the rotational speed of the photosensitive drum 3 is 3% lower than the design value, so that the image shift on the paper surface as the recording medium is the same. Does not happen.
[0063]
Next, the display means 19 for efficiently performing such a modulation frequency adjustment operation will be described in detail with reference to FIG.
[0064]
In the housing 2 of the optical scanning device 1, a handwriting input frame 27 is provided as the display means 19, and a deflection frequency segment 28 is entered by an operator according to the following method.
[0065]
Now, assuming that the distance from the scanning start position 21 to the scanning end position 22 is 210 mm (corresponding to an A4 size paper surface) and the standard value of the positional deviation of the output image is ± 1.5 mm, all the values produced in the factory Since the optical scanning device 1 is within this standard value, the deflection frequency segment 28 is classified as follows according to the deviation amount from the reference value of the deflection frequency.
[0066]
That is, -3.5% to -2.1% is 1, -2.1 to -0.7% is 2, -0.7 to + 0.7% is 3, and +0.7 to + 2.1% is 4. Divide +2.1 to + 3.5% into 5 and 5. An operator at the time of manufacturing the classification number, that is, the segment 28 may be described in the handwriting input frame 27. According to this classification, the position deviation value is a maximum of ± 1.47 mm, and the above standard can always be satisfied. In this way, by adopting the minimum number of divisions for satisfying the standard value, it is possible to reduce the number of written characters and simplify the work, compared to writing the passing speed value as raw data.
[0067]
The display means 19 is not limited to handwriting input, but can be any method that can display the deflection frequency in accordance with a certain rule in the optical scanning device 1 such as barcode printing, dip switch on / off, and writing to a semiconductor ROM. Any method may be used.
[0068]
As described above, since the segment of the necessary deflection frequency is displayed by the display means 19 for each individual optical scanning apparatus 1, in the manufacturing process of the laser printer including such an optical scanning apparatus 1, the display means 19 Since the modulation frequency can be easily adjusted according to the information, even if the deflection frequencies of the individual optical deflection elements 9 vary, the above-described positional deviation of the output image does not occur in a range exceeding the standard. Therefore, the effect that the image can be reproduced faithfully to the original image can be obtained efficiently.
[0069]
At the same time, in the manufacturing process of the laser printer including the optical scanning device 1, when the optical scanning device 1 is assembled again into another laser printer, for example, during assembly after repair or the like, the deflection frequency is set again. There is no need to perform measurement, and assembling is facilitated, and an effect that positional deviation of the obtained output image does not occur can be obtained.
[0070]
At the same time, when the user of the laser printer including the optical scanning device 1 needs to replace the optical scanning device 1 due to a failure or the like, the deflection frequency is generally measured in such a case. However, the optical scanning device 1 having the display means 19 does not need to be measured outside the manufacturing factory, and uses the segment value of the deflection frequency. Is input by a method such as panel operation or the like, there is also an effect that the positional deviation of the output image after replacement of the optical scanning device 1 can be prevented.
[0071]
From the above-described details, the optical scanning device 1 of the present embodiment is provided with a reflecting mirror 45 that is smaller in outer shape and weight than the conventional optical scanning device using a polygon mirror, and further swings sinusoidally. As a result, when the optical scanning device 1 of this embodiment is used as an image writing device in a laser printer, there is a positional deviation in the output image. It can be prevented from occurring.
[0072]
Next, the operation of the optical scanning device 1 configured as described above will be described with reference to FIG.
[0073]
The semiconductor laser 4 blinks based on the image signal and emits a laser beam. The laser beam is collimated by the collimating lens 5 and then emitted after being shaped by the opening of the lens barrel 7. The laser beam is incident on a reflecting mirror 45 formed on the light deflection element 9 of the deflector 10. Since the movable portion 44 of the optical deflection element 9 is sine oscillated by the drive portion 11, the laser beam reflected by the reflecting mirror 45 is subjected to a reciprocating deflection action sinusoidally. The laser beam that has been deflected by the optical deflecting element 9 is further converged to be imaged on the photosensitive drum 3 by the F arc sine θ lens as the imaging lens 12. At the same time, the laser beam deflected by the light deflecting element 9 is subjected to an optical path refraction action so that the photosensitive drum 3 is scanned at a constant speed.
[0074]
The laser beam that has been converged by the imaging lens 12 is folded on the optical path by the folding mirror 6 to form an image on the photosensitive drum 3 and 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 synchronization signal, and is used to obtain a reference position of an image in the horizontal direction.
[0075]
Then, a latent image is formed on the photosensitive drum 3 subjected to the optical scanning action according to the image information, and the latent image is visualized by a known electrophotographic process or the like, and then transferred onto a transfer material made of plain paper or special paper. The image is transferred and fixed by a known transfer mechanism and fixing mechanism, and is output as a hard copy.
[0076]
In addition, this invention is not limited to the Example mentioned above, A change can be added suitably.
[0077]
For example, the present invention is not limited to the above-described sinusoidal resonance type deflector composed of the optical deflection element 9 and the permanent magnet as the drive unit 11 for applying the bias magnetic field, but is laminated as a drive unit instead of the permanent magnet. Acts on deflection at the mechanical resonance point of the deflection means for deflecting the laser beam among the sinusoidal oscillating resonance type deflector using a piezoelectric element and a mechanical zoom lever mechanism and other electromagnetically driven galvanometer mirrors The present invention can also be applied to a type in which the element to be oscillated sinusoidally.
[0078]
In addition, various modifications can be made without departing from the spirit of the present invention.
[0079]
【The invention's effect】
As is apparent from the above description, the optical scanning device according to claim 1 of the present invention includes a spring portion and a movable portion that is supported by the spring portion and vibrates sinusoidally, and a light beam is applied to the movable portion. By using the optical deflecting means provided with a deflecting section for deflecting, both the outer shape and the weight can be made smaller than those of the conventional optical scanning device.
[0080]
Further, since the modulation frequency control means compensates for the variation in the deflection frequency of the light deflection means in accordance with the input from the operation means, the optical scanning apparatus of the present invention is consequently used to write an image on the scanned medium. When used for the above, there is an effect that the position of the image to be written is not different for each optical scanning device. Then, compensation for variation in deflection frequency can be achieved with a simple configuration of an input operation by the operation means.
In addition, the light deflection means is classified into a plurality of according to the deviation amount from the reference value of the deflection frequency of the movable part with a predetermined width that can satisfy the standard value of the positional deviation of the output image, and the operation means Corresponded to that classification value Therefore, the frequency of the modulation clock can be easily adjusted by the operating means as compared with the case of inputting raw data relating to individual variations in deflection frequency.
[0081]
According to a second aspect of the present invention, the optical scanning device according to the first aspect corresponds to the classification of the optical deflection means. value In accordance with the display information on the display means, the optical scanning device assembler can operate the modulation frequency adjusting means to set the modulation frequency. At the time of repair and replacement, there is an effect that the position of the image to be written does not differ for each optical scanning device even by a simple process.
[0082]
According to a third aspect of the present invention, in the optical scanning device of the first aspect, the spring portion, the movable portion, and the deflecting portion are integrally formed on an insulating substrate. Due to the torsional recovery force in the longitudinal direction, the movable portion vibrates sinusoidally, and this configuration has an effect that a small light deflecting unit can be realized.
[Brief description of the 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 an optical scanning device.
FIG. 3 is a plan view showing a state of laser beam scanning in the optical scanning device.
FIG. 4 is a side view of the optical scanning device.
FIG. 5 is a plan view of a conventional optical scanning device.
[Explanation of symbols]
1 Optical scanning device
2 body
3 Photosensitive drum
4 Semiconductor laser
9 Light deflection element
12 F Arcsine θ lens
16 Modulation clock controller
24 Modulation clock generator
25 Modulator
42 Spring
43 Spring
44 Moving parts
45 Reflector

Claims (3)

A light beam emitting means for emitting a light beam;
A scanning unit is composed of a spring unit, a movable unit supported by the spring unit and vibrating in a sinusoidal manner, and a deflecting unit provided on the movable unit, and scans a scanned medium with a light beam deflected by the deflecting unit. In an optical scanning device comprising an optical deflection means,
Modulation clock generating means for generating a modulation clock for determining the blinking timing of the light beam emitting means according to image data;
An operation means operable to input a value corresponding to a variation in the deflection frequency of the reciprocating vibration of the movable part;
Modulation frequency control means for variably controlling the frequency of the modulation clock provided by the modulation clock generation means in accordance with an input from the operation means,
The light deflection means is classified into a plurality of according to the deviation amount from the reference value of the deflection frequency of the movable part with a predetermined width that can satisfy the standard value of the positional deviation of the output image, and the operation means An optical scanning device capable of inputting a value corresponding to a classification. 2. The optical scanning device according to claim 1, further comprising display means for displaying a value corresponding to the classification of the light deflection means.     The optical scanning device according to claim 1, wherein the spring portion, the movable portion, and the deflecting portion are integrated on an insulating substrate.

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