JP2584799B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is an image forming apparatus suitable for application to an electrophotographic digital copying machine or a laser printer, in particular, the deflection characteristics (vibration characteristics) are stable, and The present invention relates to an image forming apparatus having a single point support type light deflector having a small inertia force.

BACKGROUND OF THE INVENTION In an electrophotographic digital copying machine or the like, an optical signal from a semiconductor laser or the like is used as a means for forming an electrostatic latent image on a photosensitive image forming body by an image signal corresponding to a document. is there.

FIG. 17 is a block diagram showing an example of a laser beam scanning device 30 used in this type of electrophotographic digital copying machine.

In FIG. 1, reference numeral 11 denotes a drum-shaped image forming body (photosensitive drum), on the surface of which a photoconductive photosensitive layer such as selenium is formed, and an electrostatic image (electrostatic latent image) corresponding to the optical image is formed. Image) can be formed.

The laser light scanning device 30 has a semiconductor laser 31, and the laser 31 is optically modulated based on a modulation signal obtained by binarizing image information.

The laser beam emitted from the laser 31 passes through a collimator lens 32 and a cylindrical lens 33, and is a mirror scanner composed of a rotating polygon mirror (polygon), that is, a deflector.
It is incident on 34.

The laser beam is deflected by the deflector 34, and is deflected by an f-θ lens 35 for image formation and a cylindrical lens 36.
The surface of the image forming body 11 is irradiated with the light.

The laser beam is scanned by the deflector 34 on the surface of the image forming body 11 at a constant speed in a predetermined direction a, thereby performing image exposure.

Reference numeral 39 denotes a photo sensor, which receives the laser beam reflected by the mirror 38 to obtain an index signal indicating the start of scanning of the laser beam. Writing of one line of image data is performed based on the index signal. Will be done.

When a rotary polygon mirror having the above-described configuration is used as a deflector, a polyhedral mirror is mounted on a motor, and the laser is deflected by rotating the mirror. Cause problems such as:

First, the size of the rotary polygon mirror itself becomes large, which is an overflow of miniaturization of the optical scanning device.

Secondly, the rotation noise generated when the motor is driven and the wind noise of the rotating polygon mirror increase, and noise and vibration cannot be reduced.

Thirdly, since the bearing of the drive motor for the rotating polygon mirror which is more miniaturized is usually a ball bearing, the bearing is worn by long-term use, the rotation stability is deteriorated, and the reliability is deteriorated.

Fourth, since the driving speed of a ball bearing motor is about 1 kHz in terms of frequency, it cannot be used for high-speed scanning.

When using wear-resistant bearings such as air bearings,
There are a number of problems, such as the fact that the processing accuracy of the shaft and bearings is extremely severe, and the seizure of the shaft is caused by dust and the like, and the actual deflector is large and very expensive. .

Furthermore, the rotating polygon mirror may generate noise in the optical system due to light scattering on the reflecting surface. Depending on the surface accuracy coating material of the reflecting surface, etc., the degree of light scattering also varies, but more or less light is generated, and this light is irradiated on the image forming body 11, which adversely affects the final image. .

In particular, it may cause fogging or reduce the reproducibility of fine lines. High image quality and high resolution, for example, 12 to 24 dots / mm
This is a major problem for a laser recording apparatus or the like that requires a certain level of resolution.

Such a problem can be solved by using a galvano mirror scanner as shown in FIG. 18 instead of the rotary polygon mirror.

The mirror scanner 50 includes a reflection mirror 51, a drive coil 52, and a ligament 53, as shown in the figure.

However, when such a mechanical vibration mirror is used as the deflector 34, although the above-described problem can be solved, the reflection mirror 51 and the drive coil 52 are separately manufactured, and then the Since it is attached to 53, it has the following disadvantages in addition to the increase in size of each part.

First, since the ligament is made of metal, it is difficult to swing the mirror greatly and it is difficult to swing the mirror at a wide angle.

Second, since the ligament is also made of metal, metal fatigue occurs in long-term use, and stable vibration cannot be obtained.

Further, when the material of the ligament, the mirror, and the frame supporting the same is different, stable mirror support and vibration become difficult due to a difference in (linear) expansion coefficient of the material caused by a change in ambient temperature or a large change in environmental conditions. Sometimes. When high-speed scanning is required as in a laser beam printer or a facsimile, instability of mirror support and mirror vibration affects the final image quality.

If the mirror shakes during beam scanning, the image forming body 11
This is because the location of the beam spot that hits is irregular. For this reason, straight lines may be partially bent, and equally spaced lines may be irregular.

The above problems will be described in detail later,
This can be solved by using an optical deflector made of quartz or the like as the deflector 34.

As optical deflectors, JP-B-60-57052, JP-B-60-5
No. 7053 or those disclosed in the 20th SICE Academic Lecture, July 1981, "Quartz Light Deflector" (pp. 657-658) can be used.

The optical deflectors described in such known documents are essentially developed for electromagnetic oscillographs and the like, and generally have a small deflection angle and a small frequency.

Therefore, it was difficult to apply such a deflector to an image forming apparatus such as a small-sized and high-speed laser printer, but as a result of various studies, the present inventors have used this optical deflector under specific conditions. By performing appropriate control, application to an image forming apparatus becomes possible.

[Problems to be Solved by the Invention] When an optical deflector made of quartz or the like is used as a deflector of an image forming apparatus,
Since each of the mounting portions has a different (linear) expansion coefficient, the temperature of the surroundings due to a rise in the internal temperature due to the heat generated by the heat source of the image forming apparatus main body, for example, a heat source for fixing, various motors, etc., as well as the external environment. The difference in the expansion coefficient due to the temperature change affects the light deflector side.

For example, when the light deflector is larger than the expansion coefficient of the mounting portion, the light deflector slightly bends due to a rise in temperature. As a result, the deflection angle of the light deflector is not symmetrical but slightly shifted, so that the recording area formed on the image forming body 11 varies with temperature. This variation leads to image degradation.

In order to keep the deflection angle constant, it is necessary to control the amount of current supplied to the drive coil.

In view of this, the present invention solves such a problem simply with the configuration. In addition to minimizing the influence of fluctuations in the ambient temperature, the deflection characteristics (vibration characteristics) are stable and the inertial force is small. It is an object of the present invention to provide an image forming apparatus having an optical deflector that enables stable resonance and a wider swing angle.

[Technical Means for Solving the Problems] In order to solve the above-mentioned problems, in the present invention, the image signal is deflected and scanned on the recording medium by an optical signal modulated by the image signal. In the image forming apparatus, the optical deflector that deflects and scans the optical signal is formed of a quartz substrate, and the optical deflector is formed of a reflection mirror, a driving coil, and a pair of ligaments. One of them is opened or one part of the attachment part is elastically supported so as to absorb the linear expansion of the ligament, and the other ligament is attached to the other half of the attachment part. It is characterized in that it is fixed at one point so as not to be affected by the difference in linear expansion.

Still further, according to the present invention, there is provided an image forming apparatus in which an image signal is written on a recording medium by deflecting and scanning a recording medium with an optical signal modulated by the image signal. The optical deflector is composed of a reflective mirror, a drive coil and a single ligament, and the ligament is attached so that it is not affected by the difference in linear expansion between the ligament and the mounting part to which this ligament is attached. The part is fixed at one point.

[Operation] Since either the upper end or the lower end of the light deflector is fixed to the mounting portion, the light deflector substantially expands and contracts based on the difference in expansion coefficient between the light deflector and the mounting portion to which the light deflector is mounted. Less susceptible.

Therefore, the optical deflector is substantially unaffected by expansion and contraction based on the difference in expansion coefficient between the optical deflector and the mounting portion, so that the natural frequency and torque of the optical deflector do not change much even when the ambient temperature changes. .

In addition, the natural frequency does not match the drive frequency, and the scanning speed does not change due to the change in the deflection angle.

The light deflector comprises a reflection mirror, a drive coil and a ligament, and does not use any other members. As a result, compared to the case where these members are integrally formed with the frame,
The effect of the frame can be effectively eliminated.

[Embodiment] Next, a case where the image forming apparatus according to the present invention is applied to a simple digital image recording apparatus using a laser as an optical signal will be described in detail with reference to FIG.

In a laser recording apparatus, an original is recorded on recording paper through the following process.

First, an original is incident on a photoelectric conversion element such as a CCD, and the original is photoelectrically converted and converted into a digital signal having a predetermined number of bits.

The converted signal is written on the image forming body 11 via a laser beam scanning device using a semiconductor laser beam to form an electrostatic image. Thereafter, the toner is developed by the developing device to form a color toner image.

By performing such an electrostatic image forming and developing process, a toner image is formed on the image forming body 11. Such a toner image is transferred and fixed on recording paper.

FIG. 1 shows an example of a laser beam scanning device 30 used in a laser recording device suitable for application to the present invention.

After the laser beam emitted from the semiconductor laser 31 has its beam shape corrected by the collimator lens 32, it passes through the cylindrical lens 33 and the reflection mirror 41 and is incident on the deflector 300. The laser beam is deflected by the deflector 300 in a predetermined direction at a predetermined speed.

In the present invention, as the deflector 310 of the deflector 300,
As shown in FIG. 2, an optical deflector (vibrator) is used in which a reflecting mirror 312, a driving coil 311 and a pair of ligaments 313, 314 are integrally formed.

The deflected laser beam passes through the scanning lens 42 and the cylindrical lens 36 to form an image on the image forming body 11 to form an electrostatic image.

The cylindrical lenses 33 and 36 are used for correcting the vertical shift of the reflecting mirror 312 provided in the deflector 300 when the vertical shift occurs. As the cylindrical lens 36, a plastic lens can be used.

When using such a plastic lens,
Since the surface shape of the lens can be relatively easily adjusted to the optimum shape, there is an advantage that the performance of the entire optical system can be improved.

When the tilt of the reflection mirror is very small, the above-described cylindrical lenses 33 and 36 can be omitted.

The scanning lens 42 is used for correctly forming an image of the laser beam on the surface of the image forming body 11 and for enabling the laser beam to scan the image forming body 11 at a constant speed.

Here, when vibrating at the natural frequency of the optical deflector, the deflection angle θ of the reflection mirror provided in the optical deflector 310 is θ = A · sinωt where A: the maximum deflection angle of the reflection mirror ω : Sinusoidal wave deflection operation as represented by: angular velocity t: time.

For this reason, the spot position of the laser beam is determined by the function X of X
When (θ), X (θ) = A · f · arc · sin (θ / A) where f is the focal length of the scanning lens 42, The position of the spot of the laser beam on the image forming body 11 is defined as a function X of time t.
When expressed as (t), X (t) = A · f · ωt from the above equation.

Therefore, by using the scanning lens 42 as described above, the laser beam can be converted into a uniform motion. When an electrostatic image is formed by constant-velocity motion, image quality without distortion can be obtained.

Instead of using such a constant-speed correction unit using the scanning lens 42, the correction may be performed using an electrical correction unit.

As the electric correction means, for example, those described in the 60th Annual Meeting of the Institute of Image Electronics Engineers of Japan, July 20, 1986, "Semiconductor Laser Printer by Electronic Mirror Scanning" can be used.

 FIG. 2 shows an example of the optical deflector 310.

The light deflector 310 is configured as a vibrator itself, and as shown, a reflection mirror 312, a drive coil 311 and a pair of ligaments 313, 314 for mechanically connecting these.
Are integrally formed.

As the optical deflector 310, one integrally formed by etching the same substrate is used. for that reason,
As the light deflector 310, quartz, Si, or the like can be used.

 In the embodiment, a case where quartz is used is described.

FIG. 3 shows an example of a deflector 300 using the above-described optical deflector 310.

In the figure, the deflector mounting part 320 has a substantially U-shape, and among the flanges 321 and 322 provided on the upper and lower sides, a step 322A as shown is formed on the upper flange 322, and the step 322A and the lower flange 321 are formed. The light deflector 310 is attached and fixed between them.

Therefore, a pair of holding pieces 323 and 324 having an inverted U-shape are provided, and a pair of ligaments 3 are provided between the holding pieces 323 and 324.
13,314 is pinched. The pair of holding pieces 323 and 324 are attached and fixed to the attachment section 320 in a state where their height and lateral positions are determined by the step 322A of the upper flange 322. 325 and 326 are L-shaped retaining pieces used for that purpose.

The upper ligament 313 shown in the drawing is a further modification of the ligament shown in FIG. 2, and has a shape such that the vicinity of both left and right ends of the reflection mirror 312 is connected by one ligament 313. Have been.

The mounting part 320 to which the light deflector 310 is fixed is arranged in a predetermined DC magnetic field.

Therefore, as the magnetic field generating means 327, a permanent magnet such as a rare earth element is used to obtain a desired magnetic field strength. Hereinafter, the magnetic field generating means 327 will be described as a permanent magnet.

The permanent magnet 327 has a substantially U-shaped connecting body 327A, and a rectangular parallelepiped magnetic pole 32 provided at a predetermined length inside each of both ends of the connecting body 327A so as to face each other.
7B.

The connecting body 327A is made of a magnetic material such as iron, and has a magnetic pole 327B.
Is made of a permanent magnet such as a rare earth. Instead of constituting the permanent magnet 327 with the connecting main body 327A and the magnetic pole 327B, the permanent magnet 327 may be constituted only by the magnet.

Between the pair of magnetic poles 327B, 327B, the mounting portion 320 described above
Is arranged. As a result, the deflector 310, in particular, the drive coil 311 is located in the magnetic field formed by the permanent magnet 327.

In addition, by bringing the pair of magnetic poles 327B, 327B as close as possible,
In order to increase the magnetic field acting on the drive coil 311, the illustrated example has a configuration in which the vicinity of the center of the long side of the pair of holding pieces 323 and 324 is bent toward the drive coil 311.

As shown in FIG. 4, the mounting portion 320 is fixed to the connecting body 327A by an inverted T-shaped fixing piece 328.

The deflector 300 thus configured is fixed to a mounting board (base) 290 provided in the optical scanning device 30.
Therefore, in this example, a pair of L-shaped mounting plates 291 as shown in the figure are held down on the left and right end side surfaces of the connection main body 327A, and are fixed by a plurality of fixing means 292 in this state.

As the fixing means 292, a non-magnetic screw is used.
As the nonmagnetic screw, a resin molded screw or a brass screw can be used in addition to the nonmagnetic stainless steel screw.

Attach the deflector 300 using non-magnetic screws.
In the case of fixing the mounting work, the mounting work can be performed without being affected by the magnetic field of the permanent magnet 327.

Now, when the optical deflector 310 is sandwiched and fixed by the pair of sandwiching pieces 323 and 324, the optical deflector 310 is attached and fixed to the pair of sandwiching pieces 323 and 324 whose upper and lower portions function as attachment portions.

FIG. 5 shows a case in which the optical deflector 310 shown in FIG. 2 is used, in which the lower ligament 314 side is fixed at one point by holding pieces 323 and 324.

Therefore, protrusions 340, 341 as shown in FIG. 6 are formed on one half (lower side) of the holding pieces 323, 324 facing the distal end of the lower ligament 314. Actually, the tip is fixed at one point by the pair of projections 340 and 341.

If the contact area between the pair of protrusions 340 and 34 is too large, the light deflector 310 is affected by expansion and contraction based on the difference in the (linear) expansion coefficient between the mounting part 320 and the light deflector 310. In consideration of the above, the size and the like of the pair of protrusions 340 and 341 are set within a range where such an influence is not caused.

The influence on the light deflector 310 means, for example, that the elongation of the ligament cannot be absorbed.

The upper ligament 313 side has a non-contact structure with the other half (upper side) of the holding pieces 323 and 324, or the ligament
A support member 317 having elasticity that does not hinder the thermal expansion of 313
Supported by

As the support member 317, an organic elastic substance such as urethane foam rubber or silicone rubber foam can be used after being molded into a flake shape.

With this configuration, first, the optical deflector 310 is fixed to the pair of holding pieces 323 and 324 at one point, and is less likely to be affected by the difference in the coefficient of thermal expansion between the two.

Second, since the upper ligament 313 is open or elastically supported, the inertia of the light deflector 310 is reduced.

Third, since the upper and lower ligaments 313 and 314 are rotationally supported by the holding pieces 323 and 324, stable vibration can be obtained.

In the embodiment shown in FIG. 5, the following modifications are conceivable.

1. One-point fixing (one-point support) may be on the upper ligament 313 side.

2. The protrusions 340, 341 are, as shown in FIG.
24 and may be integrated.

3. It may be fixed at one point by spot welding.

FIG. 8 shows a modification of the optical deflector 310. FIG. 7A shows a case where a bulging portion 314A is formed on the side to be supported at one point. The embodiment is formed on the lower ligament 314 side.

FIG. B shows an optical deflector 310 having a structure in which the upper ligament 313 is omitted. The lower ligament 314 side may be omitted.

FIG. 9C shows an example in which the reflection mirror 312 and the drive coil 311 are integrally formed on the front and back.

In any case, the vibrator 310 is
The drive coil 311 preferably has the same shape in the vertical, horizontal, and right directions, in order to maintain a stable inertial balance at a wide swing angle. Of course, it is more preferable in a ligament having only one side.

In addition, the configuration in which the reflection mirror 312 and the drive coil 311 are integrated front and back in this way is used to maintain a stable inertia balance with a wide swing angle, and to process the crystal oscillator to maintain a symmetrical shape. The above is also effective.

When the optical deflector 310 shown in FIG. 8A is used, it is mounted as shown in FIG. The attachment of the light deflector 310 may be upside down.

FIG. 10 shows a case where the optical deflector 310 shown in FIG. 8B is used. In this example, the optical deflector 310 is mounted so as to hang down from above.

FIG. 11 uses an optical deflector 310 having a shape similar to that of FIG. 8C. In the figure, reference numeral 316 denotes a front and back integrated portion, FIG. A shows the reflection mirror 312 side, and FIG.
Shows the 11 side.

The thickness of the quartz plate used as the light deflector 310 is 0.1 mm
About 0.5 mm is desirable.

When the optical deflector 310 is formed by processing a quartz plate, photolithography and an etching technique are usually applied to the processing means, thereby enabling fine processing. The surface of the etched optical deflector 310 is usually silver-plated to reduce the electrical resistance.

When a semiconductor laser is used as a light source, the reflection mirror 312 is plated with gold, copper, aluminum, or the like in order to increase the reflectance. Further, in order to prevent the surface of the reflecting mirror 312 from being scratched or oxidized, the surface after plating may be coated with a protective film such as SiO or SiO ₂ .

As the reflecting mirror 312, one having the following shape is used.

That is, while the shape of the laser beam that has passed through the collimator lens 32 is shaped as shown in FIG. 12A, when the laser beam passes through the cylindrical lens 33, it has a horizontally long shape as shown in FIG. It is transformed into an elliptical shape. Therefore, as the shape of the reflection mirror 312, a rectangular shape that becomes longer in the main scanning direction may be used.

The length of the reflecting mirror 312 in the horizontal direction differs depending on the focal length of the scanning lens 42, the diameter of the beam spot formed on the image forming body 11, the scanning width on the image forming body 11, and the like. According to this, about 4 to 10 mm is a desirable value.

The deflector 310 is driven by an external signal. Optical deflector 3
FIG. 13 shows an example of a separately-excited drive circuit using the circuit 10.

In FIG. 13, 330 indicates a sine wave oscillator, which is R
An oscillator using a C circuit or a crystal light deflector can be used.

In the case of using a crystal oscillator, it is preferable to divide the natural oscillation frequency of the crystal oscillator to a predetermined value and then shape the waveform into a sinusoidal waveform using a low-pass filter.

Here, the oscillation frequency, that is, the drive frequency for the drive coil 311 will be described.

As described above, the optical deflector 310 has the natural frequency f _0, and the resonance characteristic of the deflection angle θ with respect to the natural frequency f ₀
As shown in Fig. 14.

As is clear from the resonance characteristics in Fig. 14, the natural frequency
If you try to drive at a frequency that deviates from f _0, and reduces the efficiency of the deflection angle for the input current, in order to obtain the same deflection angle θ in the case of oscillating at the natural frequency f ₀ is very large input Requires current.

However, if an excessively large input current is applied to the drive coil 311, the coil may be burned out, causing a failure. Therefore, a very large current cannot be used as the drive current.

It is also conceivable that the natural frequency f ₀ of the optical deflector 310 varies, and in such a case, the drive coil 311 is driven at a frequency other than the natural frequency f _{0 in} order to unify the drive frequency f. In the case where the driving frequency f
It is desirable that the relationship between the characteristic frequency and the natural frequency f ₀ be in the range of | f−f ₀ | ≦ f ₀ / Q. Here, Q indicates the resonance sharpness of the resonance characteristics.

In other words, considering the manufacturing variation, the natural frequency
Since it is difficult to process f ₀ to be equal to the drive frequency f, its natural frequency f ₀ is limited to a range of about ± f ₀ / Q from the drive frequency f, The optical deflector 310 is to be used.

This is because the drive current for obtaining the necessary shake angle θ does not become so large within the range of the deviation of about ± f ₀ / Q.
However, the drive frequency f is always constant.

As Q, an optical deflector 310 having a resonance sharpness of about 10 to 800 is used.

For this reason, the frequency of the sine wave oscillator 330 is set to a frequency in a range that satisfies the above equation.

The output of the sine wave oscillator 330, that is, the drive signal is supplied to an offset adjuster 331 in the next stage, and its DC offset is adjusted.

When the deflector 300 is installed in the optical scanning system and the mounting position is not as designed, as shown in FIG. 15, by adjusting the DC level of the drive signal (shown by a dashed line). It is possible to adjust the right and left swing positions.

For this reason, the offset adjuster 331 adjusts the CD level so that the scanning position on the image forming body 11 becomes the prescribed scanning position.

The scanning width of the offset-adjusted drive signal is adjusted by the amplitude adjuster 332.

As an example of this adjustment method, the method described in Japanese Patent Application No. 61-81296 already disclosed by the present applicant can be used.

This method is for adjusting the deflection angle of the light deflector 310. In this case, if the scanning width on the image forming body 11 is detected and the amplitude of the amplitude adjuster 332 is adjusted based on the detected output, the scanning width can always be controlled to a constant value.

The drive signal whose DC offset and amplitude have been adjusted is supplied to the above-described drive coil 311 via the output amplifier 333.

FIG. 16 shows data of various characteristics in the above-mentioned laser recording apparatus. In this table, type I means a maximum recording paper size up to A4 size, and type 2 means A3 size. Up to.

Since the recording speed and the resolution differ due to the difference in the recording paper size, the driving frequency is appropriately selected according to the difference in the conditions.

Further, when the recording paper sizes are different as described above,
Naturally, the deflection angle of the reflection mirror is also different, so that the recording beam deflection angle is also different.

[Effects of the Invention] As described above, according to the present invention, the optical deflector is substantially not affected by expansion and contraction based on the difference in the expansion coefficient between the optical deflector and its mounting portion.
Even if the two have different expansion coefficients, the optical deflector does not bend. As a result, it is possible to reliably eliminate the disadvantage that the recording area on the image forming body fluctuates with the temperature due to the deviation of the deflection angle of the optical deflector.

When an optical deflector having a frame for mechanically connecting both ends of the ligament is used, the vibrator is affected by a difference in thermal expansion between the vibrator and the frame.

However, when the optical deflector having the above-described structure is used, since there is no frame, there is no influence from the frame, and stable vibration can be realized.

Without the frame, the etching accuracy is improved and the vibration characteristics are also improved. Further, since the original plate can be effectively used by the amount occupied by the frame, the cost can be reduced due to the increase in the number of products to be manufactured.

 Furthermore, it has the following features.

First, since the influence of the temperature on the torque can be reduced, the natural frequency of the optical deflector can be stabilized. As a result, the sensitivity can be stabilized without controlling the amount of current supplied to the drive coil.

Second, because of the one-point fixation, it is possible to prevent the effects of external mechanical vibration or sudden impact.

Third, it is possible to reduce the influence of heat generated from a heat source (motor, heater, etc.) in the apparatus.

For this reason, the image forming apparatus according to the present invention can realize a high-quality image forming apparatus with much higher reliability than before.

Therefore, as described above, it is very suitable to be applied to a simple digital copying machine or a laser recording device such as a laser printer.

[Brief description of the drawings]

FIG. 1 is a block diagram of an essential part showing an example of a laser beam scanning device used when the image forming apparatus according to the present invention is applied to a recording device for digital image recording, and FIG. 2 is an example of an optical deflector. FIG. 3 is a perspective view of an essential part showing a deflector having an optical deflector and an attached state thereof, FIG. 4 is a rear view thereof, and FIG. 5 is a front view showing an example of an essential part of the present invention. , Sixth
FIG. 7 is a partial longitudinal sectional view, FIG. 7 is a longitudinal sectional view similar to FIG. 6 showing another example of FIG. 5, FIG. 8 is a front view showing still another example of the present invention, FIG. FIG. 11 to FIG. 11 show the mounting state at that time, FIG. 12 is an explanatory diagram of the dot shape of the laser beam, FIG. 13 is a system diagram showing an example of a driving circuit of the reflection mirror, and FIG. Fig. 15 shows the resonance characteristics of the
FIG. 16 is a diagram showing a characteristic table of development conditions and the like of a laser recording apparatus, FIG. 17 is a configuration diagram showing an example of an optical system using a rotating polygon mirror, and FIG. 18 is a mechanical vibration mirror FIG. 3 is a configuration diagram illustrating an example of an optical system using the optical system. 11: drum as an image forming body 30: laser beam scanning device 31: semiconductor laser 300: deflector 310: optical deflector 311: drive coil 312: reflection mirror 313: ligament 320: optical deflection Child mounting part 323,324 ... Nipping piece 325,326 ... Retaining piece 327 ... Magnetic field generating means 327A ... Connection body 327B ... Magnetic pole 340,341 ... Protrusion

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shunji Matsuo 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation (72) Inventor Masakazu Fukuchi 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation (72) Invention Person Shizuo Morita 2970 Ishikawa-cho, Hachioji-shi, Tokyo Inside Konica Corporation (56) References JP-A-54-56848 (JP, A) JP-A-51-58962 (JP, A) JP-A-56-144871 (JP) JP-A-55-87123 (JP, A) JP-A-59-79823 (JP, U)

Claims (2)

(57) [Claims] 1. An image forming apparatus in which a recording medium is deflected and scanned with an optical signal modulated by an image signal to write the image signal onto the recording medium, wherein an optical deflector deflects and scans the optical signal. Is constituted by a quartz substrate, and this optical deflector is constituted by a reflection mirror, a drive coil and a pair of ligaments, and one of the pair of ligaments is opened or the ligament is mounted on one half of a mounting portion. While being elastically supported so as to absorb linear expansion, the other ligament is fixed to the other half of the mounting portion at one point so as not to be affected by the difference in linear expansion between the ligament and the mounting portion. An image forming apparatus, comprising: 2. An image forming apparatus in which a recording medium is deflected and scanned with an optical signal modulated by an image signal so that the image signal is cut off on the recording medium. The optical deflector is composed of a reflecting mirror, a drive coil and a single ligament, and the optical deflector is composed of a quartz substrate. Is fixed to the mounting portion at one point.