JPS58121067A - Picture formation device - Google Patents

Abstract

PURPOSE:To cancel blur of an exposing position due to vibration, by detecting the vibration of a prescribed part of a laser beam printer, adjusting the phase and amplification factor of its value, and after that, applying it to an optical system element vibrating means. CONSTITUTION:In accordance with picture information in a page memory 9, an output of a laser 8 is modulated. An oscillated laser beam is reflected by a rotary polyhedral mirror 10, condensed by a lens 11, reflected by a fixed mirror 12, and made incident to a photosensitive drum 1. In order to correct a fact that an optical system is vibrated of a motor M1 for rotating the photosensitive drum 1, and a beam exposing position is blurred, vibration of a drum shaft 39 is detected by a sensor A5. Its value is amplified and phase-shifted, and is applied to means A1-A4 for vibrating an optical system element. For instance, the fixed mirror 12 is fitted to a supporting body 14 vibrated by an electromagnet 18, and a beam reflecting position is detected by photodiodes 151, 152.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus that forms an image corresponding to recorded information by scanning a photoreceptor with a light beam.

An image forming apparatus that scans an electrophotographic photoreceptor with a laser beam modulated in accordance with recorded information is used as a device for visualizing computer output signals or electrical signals from image information output means. It is publicly known. In such a device,
The laser beam scans the electrophotographic photoreceptor in a direction perpendicular or substantially perpendicular to the direction of movement of the electrophotographic photoreceptor. The moving direction of this beam is the main scanning direction. The moving direction of the photoreceptor is the sub-scanning direction. Since the photoreceptor is moving, the incident position of the beam on the photoreceptor changes in the sub-scanning direction each time one beam scan in the main scanning direction is completed and a new scan is started. By the way, if the relative incident position of the beam on the photoreceptor deviates from a predetermined position in the sub-scanning direction, in other words, the difference between the previous scan II (trajectory of movement of the beam on the photoreceptor) and the current scan line If the distance between the two images changes from the predetermined distance, the interstitial quality of the resulting image will deteriorate.

Conventionally, no measures have been taken to prevent the above-mentioned disadvantages other than making the device vertical and rotating the photoreceptor smoothly with strong torque.

This means that when obtaining a resolution of l Odot / saij degrees, it is possible to suppress the deviation in the scanning line interval within 1007111 by making the optical system and photoreceptor driving part vertical, and the dot per IW This is because the deterioration in image quality was not noticeable, partly because the number was small.

However, when aiming to increase the speed of these devices or increase the density of images, deviations in scanning line intervals become a major problem. In other words, since a device always has a mechanical drive system (consisting of drive waves and drive force transmission means), vibrations generated by the drive system may distort the optical path, or changes in the torque of the drive force transmission means may cause The rotation of the photoreceptor itself generates minute vibrations in the direction of rotation, causing a shift in the relative incident position of the scanning beam onto the photoreceptor. If this deviation is less than the scan interval design value of 1111Il, it will not be much of a problem, but if it becomes about the same size, the influence on the image will become extremely large. Naturally, this 1i1jIli
i becomes more important as the speed of the device increases, and as the density of the image increases, that is, the interval between scanning lines decreases.

A numerical example is as follows.

Beam diameter 120μ, beam scanning line spacing design value 83μx
Assume that EI (12dots/m,). In this case, if the photoconductor is scanned with a single mode laser beam at equal scanning intervals, the spatial intensity distribution of the beam pot on the photoconductor is considered to follow a Gaussian distribution, so the integrated beam in the sub-scanning direction For example, the light intensity can be expressed as shown in Figure 1 (the light intensity is a linear graph normalized to the maximum value).
It is taken on a scale. ). If the scanning beams are alternately turned on and off one by one for each scan, the result will be as shown in FIG.

In order to obtain the best resolution on an image, image forming process conditions such as photoreceptor sensitivity, charge amount, and developing bias must be set so that black and white can be output on the image using the scanning beam exposure shown in Figure 2. is preferred. In addition, in order to obtain beautiful images with no scanning traces, in the case of a method (hereinafter referred to as a positive system) in which the scanning side light outputs white areas hit by the light as shown in Figure 1, it is necessary to use a uniform image. In the case of a method that outputs white and black where the light hits it (hereinafter referred to as a negative system), it is necessary to select and adjust the above process conditions so that a uniform black -image output is obtained. good. The larger the interval between beam scanning lines is, the larger the light intensity multiplier in FIG. 1 becomes. In general, a black scan mark on a white background gives a greater degree of visual discomfort than a white scan trace on a black background, so the tolerance range of L is larger in a negative system. In this example, for example, using a negative system, a photoreceptor area exposed under a light intensity of 06 or higher is turned black, and a light intensity of u
The above objective is achieved if the process conditions are set so that areas of the photoreceptor that are exposed to less than 6 or no light output as white. Even when black and white changes continuously, if the intermediate density corresponds to a light intensity of about 05, sufficient 137 N can be obtained.

Now, in the above-mentioned apparatus, the relative incident position of the beam on the photoreceptor in the sub-scanning direction is maximum amplitude 120 μm 1 period 10
Assuming that the light beam moves under the influence of the sinusoidal vibration of scanning, the integrated light beam intensity in FIG. 1 changes as shown in FIG. 3.

When the vibration amplitude is further large (600 μm), it changes as shown in FIG. Further, the intensity of the analytical light beam shown in FIG. 2 changes as shown in FIGS. 5 and 6, respectively. When various types of vibrations overlap, a whirring sound is produced.

For example, the distribution of the surface potential V of the photoreceptor irradiated with the light intensity distribution of FIG. 3 is as shown in the third quadrant of FIG. 7. Curve ■ is the potential obtained when using a photoreceptor with photoreceptor sensitivity four times that of curve ■, and this shows that the situation does not improve even if the beam intensity increases four times. There is.

However, it is extremely difficult to suppress the positional deviation of the light beam scanning position on the photoreceptor in the sub-scanning direction to about 10 μm. In the optical path, a deflection scanning means such as a rotating polygon mirror, a beam spot imaging means such as a tθ lens, and in some cases a path direction changing mirror are arranged, and these optical devices are held in a cage during beam scanning. This is because it must be made so that it is not affected by vibrations. −
For example, there is a path direction changing mirror between the TLL lens and the photoconductor, and the distance between the mirror and the photoconductor surface is 200 mm.
If this is the case, in order to suppress the deviation of the scanning line position on the photoreceptor in the sub-scanning direction to 100 μm, the angle of the vibration fall on the mirror must be within 17 minutes. Furthermore, if something with a large rotational load, such as a blade cleaner, comes into contact with the photoconductor, the photoconductor's elastic force will be
It is not easy to keep it down to about 0 μm. These causes deteriorate the resolution of the output image and result in significant beam scanning patterns in the image.

It is an object of the present invention to overcome the above-mentioned disadvantages and to provide a light beam scanning MiIli imaging device that reduces the influence of mechanical vibrations on the image.

The present invention will be described in detail below with reference to the drawings. FIG. 9 is an explanatory diagram of an example of a light beam scanning type image forming apparatus to which the present invention can be applied.

In FIG. 9, the drum-shaped electrophotographic photoreceptor 1 is rotated in the direction of the arrow by a motor M via a well-known driving force transmission means T including a gear train, a chain sprocket mechanism, etc.

As the drum 1 rotates, its surface is first uniformly charged by a corona discharger 2 and then irradiated with a light beam 3 of infrared, visible or ultraviolet light. As a result, an electrostatic image corresponding to the desired recorded information is formed on the drum 1, and this electrostatic image is developed and visualized using toner according to the developer number.

The visible toner image obtained by development is transferred to a transfer corona discharger 6.
The image is transferred to paper 6 under the action of , and then fixed on this paper 6 by a fixing device (not shown). On the other hand, after the transfer, the drum 1 is cleaned of residual toner by a blade-like cleaner 7 that is in contact with the drum, and is then reused.

A laser beam generator 8 outputs a laser beam 3 whose intensity is modulated by an input signal from a page memory 9 in which recorded information is stored. A polygon mirror 10 is driven by a motor M to scan the laser beam 3 in a plane perpendicular to the plane of the paper. fθ lens 11
The speed of the beam 3 scanning the photosensitive drum 1 is corrected to approximately constant speed, and the beam 3 is focused onto the drum 1. A fixed mirror 12 deflects the beam 3 from the lens 11 and directs it toward the drum 1.

Now, the rotation of the polygon mirror 10 provides main scanning (scanning of the beam 3 in a direction substantially parallel to the rotation axis of the drum 1), and the rotation of the drum 1 provides sub-scanning (scanning in a direction perpendicular to the main scanning direction). Relative movement of the beam 3 around the circumference of the drum)
give.

The scanning line interval in the scanning direction and the interval between partial beam trajectories are determined by the number of mirror surfaces of the polygon mirror 1O, the rotation speed, and the rotation speed of the drum 1. Since the main scanning speed of the laser beam 3 on the drum 1 is much faster than the rotational speed of the drum, the relative positional deviation between the beam and the photoreceptor in the sub-scanning direction mainly causes image deterioration as described above. become.

FIG. 9 shows an example of vibration countermeasures for the mirror 12. In FIG. 10, reference numeral 13 indicates a part of the main body of the 1.1Ili image forming apparatus, such as a beam, on which a mirror support 14 is fixedly installed, and furthermore, a mirror 12 is fixedly mounted on the support 14. There is. A sensor 15 for detecting mechanical vibration of the mirror 12 is a sensor 15 fixedly arranged on the mirror 12 with an incident point 12' of the beam 3 on the mirror 12 when the mirror 12 is vibrating.
in photodiode P), , 15. and a mirror support 14 for the differential amplifier (see Figure 9).
IP (which vibrates integrally with the mirror support 14) outputs an electrical signal in response to mechanical vibration of the diode 15z, 15. mirror 12
When is in the normal position, beam 3 will not be incident, but
When the mirror 12 vibrates clockwise as shown by the arrow Htle1, the beam enters the diode 15□, and vice versa.
6. If it vibrates counterclockwise as shown in , diode 1
52 so that the beam is incident on it.

In any case, the signal obtained from the differential amplifier 1115m of this senna is converted into an actuator voice drive signal by a control device to be described later. The actuator is a fixed magnet 1 fixed to the mirror support 14 and a solenoid coil 18 provided opposite thereto. coil 18
is fixed to a support 19 (integrated with the support 14) fixed to the @13.

Vibrational power corresponding to the vibration of the mirror 12 is applied to the coil 18 by a control device, which will be described later, to form a fluctuating magnetic field.

As a result, a photographing force is generated in the magnet 17 that counteracts the vibration force of the mirror 12 caused by the vibration of the motor or the gear train of the driving force transmission means, and the vibration of the mirror 12 is canceled out.

An example of the control device will be explained with reference to FIG.

First, the operation of this control device will be briefly explained.The operation modes are divided into a vibration analysis mode and a vibration removal mode.

In the vibration analysis mode, the sensor detects the mechanical vibration of the mirror, decomposes the vibration into multiple local vibrations, and detects and stores the frequency, width, and phase difference of each unique vibration. .

By forming a plurality of unique vibration signals based on the above-mentioned stored information and composing them, a vibration signal corresponding to the vibration of the mirror can be obtained. By activating the actuator based on this vibration signal, it is possible to apply a vibration force to the mirror that counteracts and cancels the vibration of the mirror caused by the vibration force of the motor, gear train, etc. However, it is necessary to synchronize the vibration signal with the vibration of the mirror. In other words, it is necessary to make the phase of the vibration signal correspond to the phase of the vibration of the mirror. Furthermore, if necessary, it is also preferable to correct the amplitude of the vibration signal to a strength that can sufficiently reduce the vibration of the mirror and that can operate the actuator.

Therefore, in the vibration removal mode, the vibration signal is used to operate the actuator, and the signal from the sensor is used to change the phase and amplitude of the vibration signal applied to the actuator, thereby reducing the vibration of the mirror.

To be more specific, in the vibration analysis mode, the vibration detection quantity sensor 16 attached to the mirror 12 detects the vibration of the mirror 12.
An electrical signal output corresponding to the amount of vibration is first inputted to the terminal a by the changeover switch 8Wl.

The electrical signal changes depending on the amount of vibration of the mirror 12.However, the vibration of the mirror 12 is a superposition of several natural vibrations, which are not very large. Fourier transform is used to separate the periods of a multi-period signal, but fast Fourier transform (F IF T )*1111jHJ'chiraretei;6 is a method for processing finite data at high speed.
0*riC(1)'1pytT By using the arithmetic unit, it is possible to know not only the period but also the phase and intensity corresponding to this period. That is, the FFT calculator 20 in the figure converts the electrical signal from the sensor 15 corresponding to the vibration of the mirror into a digital quantity, and by taking in a predetermined number of data, the natural period f of each natural vibration and the corresponding phase φ are calculated. and strength (
amplitude) is written to the table memory 21. memory +2
1 is written in descending order of strength.

Although this figure shows an example in which two natural vibrations are extracted, this can easily be expanded to the required number. However, in practice, it is sufficient to extract at most several pieces of natural vibration information and store the period, amplitude, and phase of each.

After the vibration analysis mode is finished, the switch 8Wl is switched to the contact position, and the switch 19W2 is closed. (
Switch 811 is open in vibration analysis mode. ) This starts the vibration removal mode.

P L LM oscillators 22, 23 and variable gain amplifier 24.
25 indicates the period, phase, and period written in the table memory 21.
This is means for synthesizing a signal that approximates the natural vibration from amplitude data. That is, the ppb oscillators 22 and 23 generate sine waves each having a constant amplitude based on the period (ie, frequency) information in the table memory 21, and give a phase to each synchronous sine wave. Variable gain amplifier 24.25
amplifies the above sine wave according to the vibration frequency in the table memory 21, and these amplified sine waves of each frequency are combined (arithmetic addition) in the adder 2, and the result is calculated in the vibration analysis mode. A signal that approximates the output vibration signal of the sensor 15 is synthesized.

That is, the PLL oscillator 22 and the variable gain amplifier 24 generate a first vibration signal having the frequency, amplitude, and phase of one of the two natural oscillations, and the PLL oscillator 23,
The variable gain amplifier 25 forms a second vibration amplitude having the frequency, amplitude, and phase of the other of the two natural vibrations, and this lhl and the second vibration amplitude are added by a calculator 27. As a result, a third vibration signal corresponding to the vibration of the mirror 12 when the actuator 18 is not activated is obtained. This third vibration signal is then processed by a variable phase shifter 31 and a variable gain amplifier 32 that control its phase and amplitude, respectively.
, is applied to the actuator 18 via the switch SW2. This causes the actuator 18 to actuate and apply a vibrating force to the mirror 12. The sensor 15 thus forms an output signal corresponding to the vibration of the mirror 12 in the actuated state of the actuator.

Now, the output signal of the sensor 15 is applied to the low-pass filter 28 via the switch SWI connected to the contact bk. A very high noise component of this signal is cut by a low-pass filter 28, and a relative change amount in the amount of vibration of the mirror 12 is obtained by a change amount detector 29 using diode detection or the like.

In response to this change, a control circuit 30 including a microcomputer controls the overall phase and amplitude of the third vibration signal using a variable phase shifter 31 and a variable gain amplifier 32, respectively, to provide a drive signal to the actuator. shall be.

The control of the first full phase shifter 31 and the variable gain amplifier 32 will be described as follows.

First, variable gain amplifier 32! Fix the amplification factor G and leave at °C.

Next, the phase shift amount P of the variable phase 931 with respect to the synchronization time pace generator 26 is set to 0, and the actuator 1
Operate 8. At this time, the output v of the change amount detector 29 is obtained.

Next, with the amount of phase shift) set to 21, the actuator 18
Activate. At this time, the output V of the envy amount detector 29 is obtained. Furthermore, the phase shift amount P is (0-)-PI +
Actuator 18 is actuated as Pi), and detector 2
9 is the detected vibration amount output V.

tlO we I V1 + 'I'S, v・nVx < v, If the value does not hold, VO(-71g
As Ml 4- Vm @ VO4- (output of the detector 29 when Pl-F+Pl), To > Vz <
Repeat until Vm is reached.

V・NVz (Phase shift to obtain V when it becomes VO) The amount obtained by subtracting Pl from JIIP minimizes the vibration of the mirror 12 when the vibration of the third vibration signal is fixed. This is the minimum value of the amount of phase shift that can be achieved. (still,
For example, V, +-v1 is lazy to replace - of To with Vl. In other words, the phase shift amount P of the variable phase shifter 31 relative to the time pace generator 26 is sequentially shifted by Pl, and P=nXP1
The output of change-detection 41 #29 when P=(n
+l ) X Search for n such that it is smaller than the output of the detector 29 when pi and the output of the detection @ 29 when P==(n-1)XPI.

By setting the variable phase shift IP to the time base generator 26 to nXPl, the vibration of the mirror 12 is minimized while the amplitude of the third vibration signal that drives the actuator 18 is fixed. In other words, the vibration of the mirror 12 can be minimized. The phase of the third @ motion signal is detected, and this phase information is fixed and transmitted to the ul poor phase shifter 31. Therefore, the variable phase shifter 31 is connected to the adder 2.
@33 vibration signal from the device is output with the detected phase.

A flowchart for determining the required phase shift amount of the nJ phase shifter 31 with respect to the time base generator 26 is shown in FIG. In the figure, Sun indicates a subroutine that performs a prefix phase shift of P to the variable phase shifter 31 and takes in the output from the detector 29.

Next, when the required phase shift amount is determined, the amplification factor G of the variable gain amplifier 32 can minimize the vibration of the mirror 12 while keeping it fixed and applied to the variable phase shifter 31.
Find in the same way. That is, first, the amplifier G of the variable gain amplifier is set to 0, and the actuator 18 is operated. At this time, the output V·' of the time-varying filter detector 29 is obtained.

Next, actuate the actuator by setting the above increase G to Gx. At this time, the output v1'k of the detector 29 is obtained.Furthermore, set the amplification factor G to (0+(h+OA)) and actuate the actuator 18 to detect Output y of the device 29
, / get o yo/ e V1' I V/ to -V
・If '>v−h'<vru' does not hold, then V・'4−
Vl', Vz'←Vm', Vl' 4-
(output of the detector 29 when G 4 - G + Gz), repeat until V·'>vλ/ (V-/).

The value obtained by subtracting 01 from the amplification factor G to obtain v' when V・'>Vz'<Vs' corresponds to the minimum amplitude that minimizes the vibration of the mirror 12 of the #I3 vibration signal. . In other words, by sequentially shifting the amplification factor of the variable gain amplifier 32 by G, detect when G=nXGx! 2
Detector 2 when the output of 9 is G=(n+1)xGl
9 and the output of the detector 29 when a=(n-1)xGz. Thus, the amplification factor of the variable gain amplifier 32 is determined. That is, the amplitude of the third vibration signal that minimizes the vibration of the mirror 12 is detected, and this amplitude information is fixed and transmitted to the variable gain amplifier 32.

The variable gain amplifier 32 then outputs the vibration signal from the variable phase shifter 31 with the detected amplitude.

The 70-chart for determining the required minimum amplification factor of the variable gain amplifier 32 is shown in FIG.

Husband A G, G, i, :, Y * V @ # V
z e Vs respectively v′.

It can be obtained by replacing with y, /s y, /e' y, /.

When this UJ is 8uB, variable gain amplifier 3 has an amplification factor of G.
2 and takes in the output from the detector 29.

When the amount of vibration of the mirror 12 becomes approximately l/f as described above, the situation shown in FIG. 7 is improved as shown in FIG. 8. The m-image formed in this case has sufficient brightness and darkness contrast, and the visualization threshold setting range is significantly increased as indicated by Vlat. Note that *m in II s K indicates the state when the beam is oiled.

The above vibration analysis mode and vibration removal mode are for motor M.
Yu 2M gallery started operating, drum 1, multi-sided ll! It is advisable to carry out this process after the rotation of the lO starts, but before the scanning of the drum 1 with the laser beam modulated by the information to be recorded is started. After starting scanning the drum l with the laser beam modulated by the recorded information, the variable phase gi 31 and variable gain amplifier 32 are calculated using the information on the necessary phase shift ) lit and necessary amplification factor obtained in the vibration removal mode, respectively. and controls the phase and amplitude of the vibration signal from #27 to be applied to the actuator 18 so that the vibration of the mirror 12 is minimized.

In addition, as a vibration sensor, a coil 3 is used as shown in Fig. 14.
A magnet 34 is movably provided with respect to the magnet 3.
4 to a vibrating object such as the mirror support plate 14,
A device that holds the coil 33 in an immobile state and detects current changes in this coil, or a capacitor configured with two electrode plates 35 and 36 as shown in FIG. 16, and one electrode plate 3
5 is provided movably relative to the other electrode plate 36, and
It is also possible to use a device in which the electrode plate 35 is fixed to the vibrating object to be detected, the electrode plate 36 is held immobile, and the amount of charge in the capacitor is detected.

In addition, as a sensor for detecting the rotational vibration of the ivy drum 1 and the polygon mirror 10, a disk-shaped magnet 3 is used as shown in FIG.
7 is fixed to the rotating shaft 39 of the drum L or the polygon mirror 10 so as to rotate, and the coil 3 is attached to this rotating magnet 3.
A device that detects changes in the coil 38 by facing the sun can be used. and fixed optical elements 8, 11° 12
The magnet 1f and fill 18 shown in FIG. 1O can be used as compensation power generation means. Further, in order to compensate for the rotational vibration of the drum 1 and the polygon mirror No., it is sufficient to use the one shown in FIG. 416. That is, in order to reduce the rotational vibration of the drum 10, two sets of devices shown in FIG. 16 are used. One set of them is used as a one-turn vibration detection means as described above, and the other set is used as a compensation vibration force forming means. When the device shown in Fig. 16 is used as a compensating vibration force forming means for the drum 1 or multi-plane IQ, three disks (in this case, ordinary metal plates may be used instead of circular magnets) are attached to the anatomical axis. 3
9, and connect the gain amplifier 3 shown in Fig. 11 to the fill 38.
2 outputs may be applied. As a result, a vibration braking force is applied to the disc 37 that opposes the power of the drum 1 and the polygon mirror 100 rotations, and the above-mentioned rolling movement is prevented or reduced.

Ideally, the vibration prevention or reduction device as described above should be provided in each of all the elements constituting the image forming apparatus. Elements 8.10, 11, 1 constituting the optical system
At least one of 2 may be provided for the drum 1 as shown in A6. And A, , A2.
A3. It is even better to provide at least one of A4 and A5, and even better to provide all of A1 to A5.

In any case, vibration analysis is not easy, and vibrations that were not considered during the device design may occur due to the material shape of the entire device or each component.

The present invention not only solves these problems, but also improves gear
It is also possible to cope with changes in the following movement pattern due to aging, such as #t.

If the present invention is used, it is possible to realize an mw forming device with high performance and 11i6 resolution at a low cost, and since the present invention can operate without being limited to the operating sequence of a wIj image forming device, the device design can be improved. The degree of freedom is extremely large.

The present invention is applicable to other image forming apparatuses such as image forming apparatuses employing the so-called magneto-optical recording method in which a laser beam is irradiated to raise the irradiated part of a photoconductor to a temperature higher than one Curie temperature, thereby causing a change in magnetism due to 6ζ. It can also be applied to

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams of the intensity distribution of a light beam on a photoreceptor when there is no vibration in the apparatus. 3 to 6 are explanatory diagrams of the light beam intensity distribution on the photoreceptor when the relative surface incident position of the original beam on the photoreceptor oscillates. FIG. 7 is an explanatory diagram of the photoreceptor surface potential distribution when it has the original beam intensity distribution of FIG. 3. #! FIG. 8 is an explanatory diagram of the effect of one embodiment of the present invention. FIG. 9 is an explanatory diagram of an example of an image forming apparatus. FIG. 10 is an explanatory diagram of an example of #'i movement sensor and compensation vibration force forming means. FIG. 811 is a block diagram of an example of a control device. FIG. 12 is an explanatory diagram of an example of a vibration sensor, and FIG. 13 is a flowchart explanatory diagram of the operation of a control circuit for implementing the vibration centering mode. FIGS. 14 and 15 are explanatory diagrams of other examples of vibration sensors. FIG. 16 is an explanatory diagram of a sensor for rotational vibration of a rotating body and a compensating vibration force forming means for counteracting the rotational vibration. 1 is an electrophotographic photoreceptor, 3 is a light beam, 8 is a laser beam oscillator, 10 is a rotating polygon mirror, 11 is a lens, 12 is a mirror, 151.15. 17 is a photo sensor, 17 is a magnet, and 18 is a coil. Applicant Canon Co., Ltd. Agent Gi Marushima - C, Ly,,, -: No. 1 (2) 9th direction It'go-Atva*a#Hal! ! i mark 4th figure 1t4nll attack (h! Zahi t page 71
Aoi Honpaku Gai αI seat Ho soft beam T

Claims (1)

[Scope of Claims] An image forming apparatus that forms a desired image by scanning a photoreceptor with a light beam, comprising: a detection means for detecting vibration of a predetermined portion of the apparatus; and a detection means for scanning the photoreceptor with a light beam. vibrating force forming means for forming a vibrating force capable of vibrating at least one optical element that vibrates the optical means; and longitudinal movement of the relative incident position of the light beam on the photoreceptor in the direction of movement of the photoreceptor. An image forming apparatus comprising: control means for controlling the vibration force forming means in response to an output signal of the detection means in order to reduce the vibration force generation means.