JP3015300B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light beam
And an apparatus for forming an image by irradiating light. [0002] 2. Description of the Related Art Conventionally, a multiplex having a plurality of optical scanning means has been proposed.
As an image forming apparatus, for example, the one shown in FIG.
Have been. FIG. 11 shows a 4-drum full-color image forming apparatus.
It is a schematic diagram which shows an arrangement | positioning.
1M, 101Y, and 101BK are cyan and magenta, respectively.
Image form to form images of each color
Station, and the image forming station 101
C, 101M, 101Y, and 101BK are photosensitive
Ram 102C, 102M, 102Y, 102BK, light running
Inspection means 103C, 103M, 103Y, 103BK and
A developing device and a cleaner are provided.
Cyan, magenta, yellow on transfer material S moving in the direction of mark A
Yellow and black images 31C, 31M, 31Y, 31
BK are sequentially transferred to form a color image. In this way, a plurality of image forming stations are
In an apparatus having the same transfer material S,
Transfers images of different colors to each image forming station
If the transferred image position deviates from the ideal position,
In the case of color images, the gaps between images of different colors
In the case of a color image,
If the degree becomes severe, it will appear as a color shift,
The quality was significantly degraded. [0004] By the way, the type of misalignment of the transfer image
12 (a), (b), (c) and (d)
As described above, the displacement in the transfer material S transport direction (A direction in the figure)
(Top margin) ((a) in the figure), scanning direction (A in the figure)
Misalignment (left margin) in the B direction perpendicular to the direction
(FIG. (B)), a tilt shift in an oblique direction (FIG. (C)),
There is a deviation of the magnification error ((d) in the figure).
The overlap of the type shifts appears. [0005] The main cause of the image shift is as shown in FIG.
(A) In the case of the top margin, each image forming station
(B) in FIG.
For the left margin of each image forming station
Image writing timing, that is, scanning in one scanning line
This is a shift in the start timing.
In the case of a tilt shift, the mounting angle shift θ of the scanning optical system₁(Figure
13 (a), (b) and (c) in that order) or photosensitive drum
Angular deviation θ_Two(FIGS. 14 (a), (b),
(Formed in the order of (c)), and the magnification error shown in FIG.
In case of misalignment, optical scanning optics of each image forming station
Scanning by the error ΔL of the optical path length from the system to the photosensitive drum
This is due to the line length deviation 2 × δS (FIG. 15, FIG. 1).
6). Therefore, in order to eliminate the above four kinds of shifts,
For the above top margin and left margin,
Electronically adjust the timing of the system scan to correct the deviation,
Regarding the tilt shift and the shift due to the magnification error,
Mounting position when the scanning means and photosensitive drum are assembled into the device
Careful position adjustment so that there is no deviation in the mounting angle
Had gone. That is, the light scanning means (scanner etc.)
The tilt varies depending on the mounting position and angle with the photosensitive drum.
The optical scanning means (scan)
), Take the reflection mirror in the photosensitive drum or light beam path.
Adjustments were made by changing the attachment position and angle. [0007] SUMMARY OF THE INVENTION However, such
In the conventional example, an electrically adjustable top merge
And left margin can be almost completely eliminated
Optical scanning means (scanner), photosensitive drum or optical beam
Tilt due to adjustment of the mounting position of the reflection mirror in the optical path
It is difficult to adjust the magnification error.
There was a problem that it required power. [0008] Further, it is cited as a very important problem.
What is important is the stability of image misregistration. sand
That is, the running stability of the transfer belt as a moving body (meandering,
Deviation), position reproducibility when attaching / detaching the photosensitive drum, laser beam
Margin and left merge in the case of a robot / printer
Position shift occurs due to minute fluctuations due to instability of the
Significantly affects image quality. In addition, the main body once adjusted at the time of installing the main body and
The relationship between the optical system, photosensitive drum, etc.
Due to slight distortion that occurs when moving
A difficult readjustment is required. In addition, as such a conventional electrophotographic apparatus,
Is a high-precision image forming device that cannot be compared
The thermal expansion and contraction due to the ambient temperature of the body frame.
Is a major problem.
It was a title. Therefore, the present invention has been made to solve the above-mentioned problems of the prior art.
It was done to solve a point.
Roller is an image forming apparatus that can form images without misalignment
There is a place to provide. [0012] [Means for Solving the Problems] The problems as described above are solved.
In order to achieve the above object, the present invention
And a light beam for forming an image on the photoreceptor.
A mirror unit for reflecting and scanning the photoconductor, and the mirror
Moving means for changing the position of the
An image forming unit, and a photoconductor by the plurality of image forming units.
Moving body that moves to transfer each image formed on it
Formed by the plurality of image forming means,
Detection means for detecting a plurality of mark images transferred on the body
Forming the plurality of images based on an output of the detecting means.
No inclination of each image formed by means with respect to the reference position
Calculating means for calculating the displacement amount;
The plurality of image forming means based on the tilt amount
The position of the mirror unit by controlling the moving means
Thereby, it is formed by the plurality of image forming units.
Correction means for automatically correcting the inclination shift of each image
It is configured. [0013] BEST MODE FOR CARRYING OUT THE INVENTION [Embodiment 1] The present invention will be described below based on the illustrated embodiment.
I will tell. FIG. 1 shows a 4-drum full-color image form of the embodiment.
FIG. 2 is a configuration diagram showing a forming apparatus, wherein 1C, 1M,
1Y and 1BK are cyan, magenta, yellow,
Each image formation with black developer (toner) of each color
5 is a photosensitive drum in a station. These photosensitive windows
The rams 1C, 1M, 1Y, 1BK rotate in the direction of the arrow in the figure.
These photosensitive drums 1C, 1M, 1Y, 1BK
Around the primary charger for uniform charging,
Scanning optical device 3C as an embedding unit (latent image forming unit),
3M, 3Y, 3BK, development to visualize latent images with toner
A charger, a cleaner, and a transfer charger are provided respectively. Ma
The transfer material S is supported on the transfer belt 6a and is
In each of the above image forming stations.
The toner images of each color are sequentially transferred to form a color image.
After the transfer step, the image is fixed by the fixing device 8 and the tray 9 is fixed.
Is discharged on top. On the other hand, on the transfer belt 6a, the transfer material
The image position is detected separately from the image formed on S.
Image register marks 34 and 35
The process is performed at regular intervals for each color.
In this embodiment, a cross-shaped register
Work is used. 14 and 15 are the registers
Is a sensor for reading the mark, usually CC
D is used. CCD converts light signal to electric signal
A linear sensor commonly used in facsimile machines, etc.
Similar to the well-known image reading sensor
is there. Register mark formed on transfer belt 6a
34 and 35 are located downstream of the last station.
Through lamps 16 and 17 and condenser lenses 18 and 19
The color shift is read by the CDs 14 and 15, and the
Correction is performed by feedback control. The scanning optical devices 3C, 3M, 3
As shown in FIG. 2, Y and 3BK represent the fθ lens 20,
Gon mirror 21 and laser light source 22
It is configured to be located at a position, from the laser light source 22
The irradiated light beam L is reflected by the polygon mirror 21.
Scans through the fθ lens 20 and opens the optical box 23
The light is emitted from 23a. On the other hand, above the optical box 23
Makes the first reflecting mirror 24a and the second reflecting mirror 24b substantially perpendicular to each other.
Reflector 2 as a light reflecting means provided opposite to the corner
4 indicates that the first reflecting mirror 24a is located above the opening 23a.
The optical box 23 is fixed to a device main body (not shown).
The light beam L emitted from the first reflection mirror 24a and the second reflection
Structured so as to reach onto the photosensitive drum 1 via the mirror 24b in order
Have been. This reflector 24 has its mounting position
Independently adjusted in the directions of arrows a and b with respect to the body
It is possible to use these as adjustment means for making these adjustments.
Step motor, which is a drive source that moves linearly in steps
Actuators such as linear step actuators with
Data 27, 28 and 29 are provided. The linear step actuator used here
Is the linear motion of the output shaft of the stepping motor.
The structure is the same as the inside of the motor rotor and the output.
The shaft is formed with a trapezoidal screw.
Often used to feed the head of discs, etc.
No. As a similar method, a stepping mode
The lead screw shaft (the shaft is threaded)
), And a movable member with a screw formed on it
Can be used to perform similar actuator functions
You. For example, the screw formed on the lead screw
4P0.5 (nominal diameter 4mm, pitch 0.5mm),
When the step angle of the step motor is 48 steps / lap
If so, S = 0.5 / 48 as the advance amount S of the output unit
= 1.42 μm / step can control feed rate
Noh. In the present specification, the activi
We will call it a heater. Here, actuator 2
7 is the emission direction of the light beam L from the scanning optical device.₁
By driving in the direction, the reflector 24 is substantially flat in the direction a.
The line is moved and the optical path length to the photosensitive drum 1 is shortened.
The actuator 27_TwoOptical path by driving in the direction
The length can be adjusted longer. Thus, the optical path length
By adjusting, a light beam having a predetermined spread angle
The length of the scanning line on the photosensitive drum L is, for example, shown in FIG.
Like m₀From m₁Can be changed to Further, the actuators 28 and 29 are simultaneously
In the same direction, for example, b₁By driving in the direction of the reflector
24 is the above a₁Parallel to the direction b, which is a direction substantially perpendicular to the direction
Is moved, whereby the scanning line m in FIG.₀Scan
Line m_TwoIn parallel. Also,
When one of the actuators 28 and 29 is moved
Or the actuator 28 is b₁Actu in the direction
Eta 29 b_TwoOpposite directions such as driving in the direction
When the driving in the direction shown in FIG.₀Run
Check line m_ThreeThe inclination can be changed as follows. As described above, the pair of reflecting mirrors are set at substantially right angles.
The reflector 24 incorporated in the photosensitive drum from the scanning optical device
In the optical path of the light beam up to
Tuned by tutor 27 or actuators 28 and 29
The optical path length or light beam scanning position
Each can be adjusted independently. In other words, it is arranged in a square shape
Reflector 24 having a pair of reflecting mirrors moved in the direction a
The scanning lines formed on the photosensitive drum.
Corrects only the optical path length of the light beam L without changing the position
The reflector 24 can be moved in the direction b.
Without changing the optical path length of the light beam L
Image position and angle on the drum can be corrected.
You. In this embodiment, a four-drum color printer is used.
A reflector, and a means for adjusting the position of the reflector.
Scanning line on the photosensitive drum
Magnification error based on the optical path length, top margin and reflex
The margins are corrected, and each
The color shift between the knives is eliminated. As described above, how to actually read register marks
Example of the cyan image for the method and the feedback method
Will be explained in detail. FIG. 4 shows a portion for detecting the register mark and a portion for detecting the register mark.
And then perform feedback control to each station
FIG. FIG. 4 shows the scanning line inclination and the magnification error described above.
Read the register mark written in the state where
Here is an example. A sensor for reading the register marks 34 and 35
The sensors 14 and 15 are CCDs 1 and 2, respectively. CCDs 1 and 2 are
Because the output converted to the air signal is a very low signal level,
The signals are amplified by the respective amplifiers A and are registered by the binarization circuits 50 and 51.
Electric signal CCD1 corresponding to the exact position of the star mark
P, CCD2P are obtained. CCD1 and 2 are reference
It is installed at the fixed position of 1, 2
Mark starts writing accurately, scanning line tilt, magnification from reference position
When the mark is formed at the correct position without error, the mark
The center of the image is read at the center pixel of the CCD1 and CCD2 pixels.
It is configured to be in a proper position. Also, each
The main scanning start position (left margin) of the CCD is also a reference 1,
Set the directions of CCD1 and CCD2 so that they start from 2.
are doing. FIG. 5 shows the magnification error and the deviation of the left margin.
When each occurs and when it is written properly
An example is shown together with the positional relationship between the CCDs 1 and 2. In the figure
And 1A is the output when writing at the regular position and 1B
This is the case where the displacement occurs. The register marks 34 and 35 on both sides are
CCD 1 and 2 when reading after writing 1A and 1B respectively
3A and 3B show output waveforms after binarization of. By 1A
Since the output of 3A obtained by the normal position is CCD1,
Is the main scanning start position (hereinafter referred to as CDHSYNC).
U) than t₀Image signal of register mark at time position
Is obtained as However, as shown in 1B,
The written register mark is CCD as shown in 3B
1 side is the normal position, CCD2 side is inside the normal position
t₀Shorter t_TwoAt the time of the register mark image signal
It is obtained. Thus, t₀> T_TwoNo
In such a case, the magnification should be small and adjust the magnification properly.
Then, the left margin is also about 2B from the reference position 2A.
It can be expected that the position will be shifted. In FIG. 4, the magnification error and the
About the method of detecting and correcting the shift margin deviation amount,
This will be described together with the timing chart of FIG. The CCD1 and CCD2 have CDHSYNC devices.
CDHSYNC of one main scanning period signal from the generator 70
And it can be converted to an image signal in this cycle.
You. Register marks 34 and 35 are CCD1 and CCD2
Can be obtained by reading in the order of CDHSYNC ,,
The signal output is assumed to be CCD1P and CCD2P in FIG. of
At the time of CDHSYNC, both CCDs are still registers
No image signal can be obtained because the mark has not been read.
No. In the next CDHSYNC cycle, the CCD
As an output on one side, t₁Image signal of CCD1P at position
Is obtained. t₁As described in the example of FIG. 5,
T at a given position₀Time. Further CDHSYNC cycle
Has t as the output of CCD2._TwoPosition of CCD2P
An image signal is obtained. This is as described in the example of FIG.
t₀Shorter than. This t₁And t₀Counting time
Counter 2 (62), counter 3
(63). Each counter 62, 63
There is a CLOCK terminal, and X1 CLOCK is connected to this terminal.
input. The X1 CLOCK frequency is shifted at this frequency
Higher frequencies are more advantageous because they look at quantities.
STA of counter 1 (54), counter 2 (62)
The RT signal terminal has the C of the CDHSYNC generator 70
The DHSYNC signal has been input. Also, the STOP
Each signal terminal has a counter 1 and a CCD 1P
The output signal is output to the counter 3 from the CCD 2P.
Has been entered. Therefore, at counter 2, CDHSYNC
The X1 clock frequency starts counting, and the CCD
Stops at 1P image signal input, and counts the output t
₁Is obtained as In counter 3, CDHSYN
Start counting the clock frequency of X1 from C,
Stops when D2P image signal is input, and outputs the count number
t_TwoIs obtained as T obtained₁, T_TwoThe value of
The central value t is calculated by the radiators CP1 and CP2.₀Is compared with the value of
Δt₁, Δt_TwoAs Δt₁= 0, Δt_Two= Number of -1
Value. In accordance with each value of Δt,
ROM in which the magnification movement amount and the left margin movement amount are set
Actuator for controlling magnification error, which is the first control amount in 2
The optimum movement control value of the data 27 is selected and output. Further
Next, the moving amount of the left margin, which is the second control amount, is also selected.
And outputs it as DELAY (CH). Therefore, this correction causes a magnification error and a
Shift margin shift is corrected to the correct position
Becomes possible. The magenta that follows these example actions
The red, yellow and black register marks
By repeating, all stations are corrected
You. Switch to the E terminal of counters 2 and 3 and the S terminal of ROM2.
The station selection signal is for that selection. Next, correction of the scanning line inclination will be described. When the CCD 1 is at CDHSYNC,
CCD1P which read star mark 34 is obtained.
And EXH's exclusive OR to CDHSYN
The C1 signal is erased to obtain the START1 signal. This signal
By inputting to the START signal terminal of the counter 1,
Of the CDHSYNC signal input to the CLOCK terminal.
Start und. Next, CDHSY by CCD2
When NC, register mark 35 is read and CCD2P
EX2, STOP2 by EX2 as described above.
Get the signal. This signal is sent to the STOP terminal of counter 1.
Stop CDHSYNC counting by inputting
You. Therefore, the number of CDHSYNC is output to the output of the counter 1.
Value, that is, the scanning line inclination amount N. In this example, N
= 1. Move the scanning line in the specified direction
The control values of the actuators 28 and 29 to be moved to
Select from ROM1 which has been set beforehand, and
And the actuators 28 and 29
Move. Therefore, this correction corrects the scan line tilt amount.
Is moved to the normal position. Follow this action
Magenta, yellow and black register marks
Even if it is repeated, all stations are corrected by repeating
It is. Station select to terminal E of counter 1
The signal is for that selection. Next, correction of top margin deviation
State. The VSYNC-C counter is the first station
Detects the position of the register mark to be written first.
The timing signal at which the register mark was written
Signal to the START terminal
Start counting the inserted CDHSYNC. This signal
Not just CDHSYNC
If the frequency is changed, the resolution can be further improved.
You. Then, the register manager read by CCD1 first
Stop by the START signal of the
Stop YNC counting. This value C 'is a predetermined position
Compared with the value obtained when writing a register mark to
Is selected and output to the ROM 3 for selecting and outputting the difference amount.
The top margin of DELAY (CV) at the output of ROM3
A control output is obtained. Therefore, this fix
The misalignment is corrected and moved to the correct position. this
Magenta, yellow, and black cash registers that continue to operate
By repeating for the star mark,
Modifications are made. In addition, each VSYNC counter
Since the register mark is continuous in the operation of
Register mark signal at a position that is not required but not required
Needless to say, a control signal is required to prevent the stop.
No. The control value selected from the ROM 3 is stored in the actuator.
Similarly, the control values of the
Gin shift can be corrected. Various combinations of the operations described above
Automatically and quickly correct images with various color shifts
It is. A register formed on the transfer belt
After passing through the CCD reading section, the mark
Belt cleaning such as cleaning blade 7
Cleaning device, and the next register mark
Be prepared for it. Embodiment 2 FIG. 7 shows a second embodiment of the present invention.
It is. In this embodiment, the scanning line of the color shift described above is used.
Scanning optical device (ie, scanner) for tilt, magnification error, etc.
Optical box 23 (fθ lens 20, polygon mirror 2)
1, a box in which the laser light source 22 is integrated).
Position moving means capable of adjusting the mounting position of the device with respect to the apparatus main body
It can be modified by the Less than
The mechanism is described below. In FIG. 7, reference numerals 40 and 41 denote steppings.
Motor or linear stepper described in the first embodiment
An actuator such as a actuator. Here, the actuator 40 is connected to a scanning optical device.
A, which is the direction of emission of the light beam L from the device₁Drive in the direction
Thereby, the optical box 23 is substantially parallel to the direction a along the axis l.
It is configured to be moved. As a result, the photosensitive drive
Shorten the optical path length up to the
A_TwoDrive to increase the optical path length.
Can be Thus, as in the first embodiment, the magnification error
The difference can be corrected. Further, driving the actuator 41
Thereby, the optical box 23 is moved around the axis l as a rotation center,
Thereby, the amount of inclination of the scanning line can be adjusted. As described above, the position of the scanning optical device itself is changed.
It is possible to correct the amount of color misregistration by
Become. Read the register mark below this and
Feedback of the correction amount to the actuators 40 and 41
The lock control and the reading method are all described in the first embodiment.
Same as the method. Embodiment 3 FIG. 8 shows a third embodiment of the present invention.
It is. In this embodiment, the scanning line of the color shift described above is used.
The image carrier (ie, photosensitive drum)
That can be corrected by the position moving means
It is. The mechanism will be described below. In FIG. 8A, 10C, 10M, 1
0Y and 10BK are photosensitive drums 1C, 1M, 1Y and 1B
K are flanges fixed to both ends, each of which is
The shaft support devices 11C, 11M, 11 shown in FIG.
Y, 11BK, and the shaft support device 11C,
11M, 11Y, 11BK correspond to each photosensitive drum.
Is fixed to the supporting member. In addition,
The ram is driven by a drive transmission mechanism (not shown). FIGS. 8 (b) and 8 (c) show details of the shaft support device 11. FIG.
FIG. In this figure, the shaft 10a of each flange 10
Is supported by the bearing 601. The bearing 601 is shown in FIG.
Moveable in the direction of arrow A by a guide groove not shown
The actuator 6 supported by the inner case 604
03 urges the spring 602. Also,
The case 604 is also formed by a guide groove (not shown).
07 so that it can move in the direction of arrow B which is perpendicular to arrow A
, And the spring 6
05 is energized. The actuator in this case
603 and 606 are linear sensors as described in the previous embodiment.
A step actuator or the like is preferable. This pivot support device 11 is shown in FIG.
As shown, the direction A is horizontal and the direction B is vertical.
When installed together, the front and rear actuators 6
06a and 606b are simultaneously driven in the same direction, that is, in the B direction.
When the photosensitive drum 1 moves, the photosensitive drum 1 emits a light beam from the scanning optical device.
L is moved substantially parallel to the emission direction, and the optical path length changes.
Thereby, the magnification error can be corrected. The actuators 603a, 603b
If you move one of the
To the motors 603a and 603b in directions opposite to each other.
This makes it possible to correct the scanning line inclination amount. The actuators 603a, 603b
When scanning in the same direction at the same time, the scanning line was translated.
It's the same thing, that is, adjusting the top margin
Also becomes possible. As described above, the position of the photosensitive drum itself
Correction can also correct the amount of color misregistration described above.
You. Read the register mark below this
Of correction amount to actuators 603 and 606
The back control, reading method, etc. were all described in the first embodiment.
Same as the method. Incidentally, the above-described method uses the intermediate transfer member 1
9, the image forming apparatus shown in FIG.
To other image forming apparatuses such as the image forming apparatus of FIG.
Can also be applied. In the case of FIG. 9, the register mark is intermediate
It is formed on the copying body 10 or the transfer material S, and
In this case, it is formed on the roll paper 11. The present invention also relates to a four-drum color printer.
Not only, for example, a two-color or three-color multi-color image forming apparatus or a multiplex
The present invention is also applicable to an image forming apparatus. Further, in the first embodiment, the light
Reflected in a C shape as an optical system that defines the optical path of the beam L
The case of using a reflector with a mirror was described.
The position and angle of the reflector,
The number of mirrors may be freely selected.
It may be formed integrally with the shape. In each embodiment, the actuator
The linear step actuator was explained as an example
However, besides this, for example, a normal stepping motor
Same as screwed shaft, gum, linear motor, etc.
Anything that fulfills the function
No. The position of the register mark to be formed
If the position can be formed by electrophotography,
It can be anywhere on the moving object,
The shape of the workpiece is not limited to that used in the present embodiment, but
If it is possible to detect such image shift,
It may be in such a form. As described above, the register mark
Cleaning on the belt after writing
Fur brush method and air suction method in addition to
By using it, it is more effective. Further, the CCD used for reading is
In the present invention, the number of sensors
The image is read by two places.
Increasing the number of 3 locations and 4 locations will result in more accurate image misalignment
Can be read. [0057] As described above, according to the present invention,
Based on the detection output of each mark image transferred on the moving object
To calculate the amount of tilt of each image, and based on the amount of tilt,
-Automatically correct the tilt of each image by changing the position of the
Therefore, a good image can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a first embodiment of an image forming apparatus according to the present invention. FIG. 2 is a perspective view of a main part of the first embodiment. FIG. 3 is an explanatory diagram illustrating an image shift of a transfer material. FIG. 4 is a block diagram illustrating feedback control of the phone embodiment. FIG. 5 is an explanatory diagram of a CCD reading unit. FIG. 6 is a timing chart illustrating feedback control according to the present embodiment. FIG. 7 is a perspective view of a second embodiment. FIG. 8 is a perspective view of a third embodiment. FIG. 9 is a diagram showing another embodiment. FIG. 10 is a diagram showing another embodiment. FIG. 11 is a diagram showing another embodiment. FIG. 12 is a diagram showing an image shift. FIG. 13 is a diagram illustrating an image shift due to a position shift of the optical scanning device. FIG. 14 is an explanatory diagram of an image shift due to an axis shift of a photosensitive drum. FIG. 15 is an explanatory diagram showing an optical path length error. FIG. 16 is an explanatory diagram showing a magnification error due to an optical path length error. [Description of Signs] 1 Photosensitive drum 3 Scanning optical device 6a Transfer belt 14 Sensor

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Kazuyoshi Chihisa               3-30-2 Shimomaruko, Ota-ku, Tokyo               Non Corporation (72) Inventor Yukio Sato               3-30-2 Shimomaruko, Ota-ku, Tokyo               Non Corporation (72) Inventor Yoichi Kubota               3-30-2 Shimomaruko, Ota-ku, Tokyo               Non Corporation (72) Inventor Ken Miyagi               3-30-2 Shimomaruko, Ota-ku, Tokyo               Non Corporation (72) Inventor Hirose ▲ Yoshi ▼ hiko               3-30-2 Shimomaruko, Ota-ku, Tokyo               Non Corporation (72) Inventor Kunihiko Matsuzawa               3-30-2 Shimomaruko, Ota-ku, Tokyo               Non Corporation (72) Inventor Hiroyuki Miyake               3-30-2 Shimomaruko, Ota-ku, Tokyo               Non Corporation (72) Inventor Tomohiro Aoki               3-30-2 Shimomaruko, Ota-ku, Tokyo               Non Corporation (72) Inventor Setsu Uchida               3-30-2 Shimomaruko, Ota-ku, Tokyo               Non Corporation (72) Inventor Kazuki Kanekura               3-30-2 Shimomaruko, Ota-ku, Tokyo               Non Corporation                (56) References JP-A-62-267773 (JP, A)                 JP-A-63-300261 (JP, A)                 JP-A-58-156261 (JP, A)                 JP-A-60-4951 (JP, A)                 JP-A-1-284870 (JP, A)                 JP-A-60-31168 (JP, A)                 JP-A-61-134274 (JP, A)                 JP-A-62-45275 (JP, A)                 JP-A-62-59975 (JP, A)                 JP-A-57-167034 (JP, A)                 Shokai 61-124152 (JP, U)                 Shokai 61-131165 (JP, U)

Claims (1)

(57) [Claims] A plurality of image forming units each including a photoreceptor, a mirror unit for reflecting a light beam for forming an image on the photoreceptor and scanning the photoreceptor, and a moving unit for changing a position of the mirror unit; Means, a moving body that moves to transfer each image formed on the photoconductor by the plurality of image forming means, and a plurality of marks formed by the plurality of image forming means and transferred onto the moving body. Detecting means for detecting an image; calculating means for calculating an amount of tilt deviation of each image formed by the plurality of image forming means with respect to a reference position based on an output of the detecting means; and tilt calculated by the calculating means Each of the images formed by the plurality of image forming units is controlled by controlling the moving unit in the plurality of image forming units based on the shift amount to change the position of the mirror unit. An image forming apparatus comprising: a correcting unit that automatically corrects a tilt shift of the image.