JPS63210968A - Image forming device - Google Patents

Abstract

PURPOSE:To permit normal development by controlling the circulation moving speed of a developing means in such a manner that said speed is hardly affected by a fluctuation in load on the developing means which can be circulated and moved near to an image carrying body when said fluctuation is generated by certain cause in the above-mentioned developing means. CONSTITUTION:A control means stores respectively the data on the circulation moving quantity of the developing means during the time since the preset circulation moving speed of the developing means is forcibly decelerated before the circulation speed attains a min. speed and the data on the detected value of the circulation moving quantity of the developing means during the time since the force deceleration of the circulation moving speed of the developing means at the time of the previous driving is started before the min. speed is attained. The data on the preset circulation moving quantity is corrected in accordance with the data on the detected value and the timing for starting the force deleration of the circulation moving speed of the developing means is controlled according to the corrected result. The rotating speed of a rotating body is thereby controlled in such a manner that the rotating speed of the rotating body is hardly affected by the fluctuation in the load.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to image forming apparatuses, and more particularly to color image forming apparatuses such as various color printers including, for example, multicolor electrophotographic copying apparatuses equipped with a plurality of developing devices. In books.

A multicolor electrophotographic copying apparatus as a color image forming apparatus will be described.

This type of multicolor electrophotographic copying apparatus has a structure that allows development of two colors, color copies of three or more colors, or full-color copies, for example. A photoreceptor drum formed to have a fairly large diameter and three to four developing devices disposed along the outer peripheral surface of the photoreceptor drum in close proximity to the outer peripheral surface of the photoreceptor drum. The configuration includes an image forming section consisting of various types of equipment. Each of the above-mentioned developing devices separately stores developers of yellow Y, magenta M, cyan C, black BK, etc., and the developer of each color is used to form an image on each photoreceptor drum. This system converts the electrostatic latent image of original image information into a visible image. In the multicolor electrophotographic copying apparatus having the above-mentioned configuration, four developing units must be disposed near the outer peripheral surface of the photoreceptor drum. Compared to a single-color electrophotographic copying machine that only requires 111 developing devices installed nearby, it requires more than four times the internal space for installing the developing device, and the diameter of the photoreceptor drum is also smaller than that of a single-color electrophotographic copying device. It is necessary to make the diameter considerably larger than that provided for the equipment, and it is unavoidable that the entire device will become larger and the cost will increase due to the larger size.Therefore, in order to avoid such enlargement of *a. As a countermeasure, a multicolor electrophotographic copying device equipped with a so-called rotary developing device was proposed (Japanese Patent Publication No. 93437/1983).
The outline of this proposal is that a single-rotation type developing device, that is, a substantially cylindrical housing that holds four developing units and is rotatably supported, is disposed near the outer peripheral surface of the photoreceptor drum. The electrostatic latent image formed on the electrostatic latent image is sequentially developed by the rotation of the casing with a developing device that comes to a developing position facing the outer peripheral surface of the photoreceptor drum (for details of the above proposal) (Please refer to the above publication).

Incidentally, in a multicolor electrophotographic copying apparatus equipped with a rotary developing device configured as described above, the rotating rotary developing device can be moved to a desired position (for example, the above-mentioned developing position or the home of the rotary developing device). As a positioning means, a stopper mechanism consisting of a mechanical element including a retaining portion formed on the rotating body side and a locking member provided on the image forming apparatus main body side is used as a positioning means. The casing, that is, the rotating body, is positioned and fixed at the desired position by such positioning means. However, it is clear that when an attempt is made to stop a rotating body that is being driven by the above-mentioned stopper mechanism, an impact occurs when the locking member of the stopper mechanism engages with the engaging portion of the rotating body. , the need to reduce this impact as much as possible by controlling the rotational speed of the rotating body to a low speed, and the instability of the speed control of the rotating body caused by controlling the rotational speed of the rotating body to a low speed in this way. This creates the need to resolve the issue. Therefore, as a means to simultaneously satisfy the above two needs,
So-called servo control is performed until the locking part reaches a position set in the rotational direction before the locking position where the locking member of the stopper mechanism and the engaging part on the rotating body side engage. Do.

After the retaining part reaches the position, the speed is forcibly reduced by, for example, applying a brake, and the rotating body is rotated at the lowest speed to perform positioning control in two steps. A speed control method was adopted.

However, in an image forming apparatus that employs the two-stage rotational speed control method as described above, if load fluctuation occurs on the rotating body due to some reason, the servo control is not easily affected during the so-called servo control described above. When shifting from speed control to the minimum speed control, the necessary braking force will vary, and the time it takes for the rotation speed to reach the minimum speed will vary, resulting in the time it takes for the drive of one rotating body to stop. There will be variations in the results. In particular, if the load on the rotating body increases due to, for example, toner scattering from the developing device, the aforementioned braking force will also increase, which will lengthen the time the rotating body rotates at the minimum speed, which is set in advance. It was also determined that the developing device may not be able to be moved to the developing position within the specified time, which may prevent normal development from occurring.

Therefore, the present invention has been devised in view of the above-mentioned facts, and its purpose is to prevent load fluctuations from occurring in the rotating body of a single-rotation type developing device due to any cause. It is an object of the present invention to provide an image forming apparatus capable of controlling the rotational speed of a rotating body in which the rotational speed of the rotating body is not easily affected.

R1.

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides an image carrier, a developing means that is movable in circulation to a developing position for developing an electrostatic latent image formed on the image carrier adjacent to the image carrier, and After the means reaches a position upstream of the preset developing position in the circulating movement direction and until it reaches the developing position, the circulating movement speed of the developing means is forcibly reduced. In the image forming apparatus, the control means controls a circulating movement speed of the developing means at a minimum speed and stops at the developing position, the controlling means forcibly controlling a preset circulating movement speed of the developing means. data on the amount of circulation movement of the developing means from when the circulation speed is decelerated to the minimum speed until the circulation speed reaches the minimum speed, and the circulation movement speed of the development means during the previous drive to the minimum speed after the forced deceleration started. , respectively, and correct the preset circulating movement amount data based on the detected value data, and according to the corrected result. The image forming apparatus is characterized in that the timing of the start of forced deceleration of the circulating speed of the developing means is controlled.

111' An embodiment of the present invention will be described below with reference to one drawing.

Figure 1 shows an image forming apparatus according to an embodiment of the present invention. Figure 1 shows an outline of an image forming apparatus according to an embodiment of the present invention.
As is clear with reference to the figure, one side of the device main body 100 (
The transfer material conveyance system is provided from the right side of FIG. 1 to the approximate center of the apparatus main body 100! And, approximately at the center of the 1ti placement main body 100, there is the transfer material conveyance system! It is roughly divided into a latent image forming section (2), which is located close to the transfer drum 8 constituting the latent image forming section (2), and a developing means, that is, a rotary developing device (M), which is located close to the latent image forming section (2). be done. The above-mentioned transfer material conveyance system (2) includes a transfer material supply tray 101.102 that can be attached to and removed from an opening formed on one side of the apparatus main body 10G (on the right side in FIG. 1), and the tray 101.102. Paper feeding rollers 103.104 arranged almost directly above the paper feeding rollers 103.1G4, and paper feeding rollers 103.1G4 arranged close to these paper feeding rollers 103.1G4. 06, and a contact roller 7 and a gripper 6, which are provided close to the paper feed guide 4b and arranged near the outer peripheral surface from the upstream side to the downstream side in the rotational direction.
A charger 121 for separating the transfer material and a separation claw 14 are provided, and a transfer charger 9 and a charger for separating the transfer material are provided on the inner circumferential side.
113' and a transfer drum 8 rotatable in the direction of the arrow in FIG.

Conveyor belt means provided close to the separating claw 14! 5, and a fixing unit s16 which is disposed close to the terminal end side of the conveyor belt means 15 in the conveyance direction and is adjacent to a discharge tray 17 which is detachably attached to the apparatus main body 100 and which extends outside the apparatus main body 100. Consists of.

The latent image forming section (2) includes an image carrier, that is, a photosensitive drum 2, which is disposed so that its outer circumferential surface is in contact with the outer circumferential surface of the transfer drum 8, and is rotatable in the direction of the arrow in FIG. 1; A static eliminating charger lO is disposed near the outer peripheral surface of the drum 2 from the upstream side to the downstream side in the rotational direction of the photosensitive drum 2.
, a cleaning means 11, a second charger 3, and an image exposure means such as a laser beam scanner and an image exposure reflection means such as a polygon mirror for forming an electrostatic latent image on the outer peripheral surface of the photosensitive drum 2. ing. The rotary developing device (■) includes a rotatable housing (hereinafter referred to as "rotating body") 4.
Visualizing (that is, developing) the electrostatic latent images formed on the outer peripheral surface of the photoreceptor drum 2 at positions facing the outer peripheral surface of the photoreceptor drum 2, which are mounted in the rotating body 4a, respectively. Yellow developer 4Y, magenta developer 4M, cyan developer 114C, and black developer 4BK
It has

First, the entire sequence of the image forming apparatus having the above-described configuration will be briefly described using a full color mode as an example. When the photoreceptor drum 2 described above rotates in the direction of the arrow in FIG. 1, the photoreceptor of the photoreceptor drum 2I is uniformly charged by the primary charger 3. - Next, when the photoreceptor is uniformly charged by the charger 3, image exposure is performed using the laser beam E modulated by the yellow image signal of the original (not shown), and the electrostatic charge is generated on the photoreceptor drum 2. A latent image is formed and the electrostatic latent image is developed by the yellow developing device 4Y, which has been previously placed at a developing position by the rotation of the one-rotator 4a.

On the other hand, the paper feed guide 4A, the paper feed roller 106. The transfer material conveyed via the paper feed guide 4b is held by the gripper 6 at a predetermined timing, and is electrostatically held by the contact roller 7 and the electrode facing the corresponding contact roller 7. It is wound around the transfer drum 8. The transfer drum 8 rotates in the direction of the arrow in FIG. The image is transferred by the transfer charger 9 at the portion where the outer circumferential surface is in contact with the image.

The transfer drum 8 continues one rotation and transfers the primary color (first color).
Prepare for transfer of magenta (in the figure).

On the other hand, the photosensitive drum 2 is neutralized by the charger 10, cleaned by the cleaning means 11, charged again by the primary charger 3, and subjected to image exposure as described above using the primary magenta image signal. . The rotary developing device rotates while an electrostatic latent image is formed on the photosensitive drum 2 by the magenta image signal by the image exposure, and is fixed at a predetermined developing position where the magenta developing device 4M is located. Following the predetermined magenta development, the process described above is also carried out for cyan and black colors, respectively.

When the transfer of the four colors is completed, the four-color developed image formed on the transfer material is neutralized by each charger 10, 13, the grip of the transfer material by the gripper 6 is released, and the transfer material is It is separated from the transfer drum 8 by the separation claw 14,
The image is sent to the fixing unit 3ts by the conveyor belt 15, a series of full-color print sequences are completed, and a required full-color print image is formed.

FIG. 2 shows a more detailed configuration of the above-mentioned rotary developing device.A rear side plate 11 is provided at the rear end of the above-mentioned rotating body 4a, and the rear side plate 11 has a supporting frame. It is fitted and attached to the rotating ring 4b of the rotating body 4a. The rear side plate 11 is formed in the shape of a ring, and a gear lla is formed on the outer periphery of the rear plate 11, and an engagement groove 18a and the engagement groove 37$1 are formed on the outer periphery of the rear side plate 11.
8a and a continuous guide edge 18b are formed on the rotating body 4a.
Two stopper plates 18 are attached, which constitute a part of the positioning means Z for ensuring a predetermined stopping position. A shielding member xI that receives irradiated light and always reflects a constant amount of light is fixed to the rotary ring 4b so as to rotate together with the rotary wheel 4b, and in the embodiment, the shielding member XI is It is assumed that it is arranged and fixed at a position where it faces the yellow developing device 4Y described above and can rotate together with the yellow developing device 4Y.

Further, in detail about the shielding member x1, the shielding member x1 is attached to the image forming apparatus main body side, which will be described later, as the rotating body 4a rotates.
tXY, XM, XC, XBK.

It is assumed that the position is set so that the light emitted from each of these photosensors can be received and reflected toward each of the seven photosensors by facing each of the xOs in turn. On the other hand, on the image forming apparatus main body side, photosensors XY and XM as detection means for detecting the rotational position of the rotating body 4a are located at positions where they can face the rotationally moving shielding member x1, respectively, at a predetermined interval. ,XC,XBK,XO
is installed. As is already well known, the above-mentioned photosensor includes a light-emitting element that emits a certain amount of light, and a light-receiving element that outputs an electric signal depending on the amount of light received. For the photosensor xY, when the yellow developer 4Y is at the development position, the sensor XY faces the rotational position of the shielding member x1, and for the photosensor XM, when the magenta developer 4M is at the development position. The sensor
is opposed to the rotational position of the shielding member x2, and the photo sensor xC is arranged so that the sensor xC is opposed to the rotational position of the shielding member XI when the cyan developer 4C is at the development position. , the photosensor XBK is positioned so that when the black development: 1148K is at the development position, the sensor XBK faces the rotational position of the shielding member XI, and the photosensor It is assumed that each developing device is positioned at a position opposite to the rotational position of the shielding member x1 when it is not at the developing position.

A rotational drive motor 12 for rotationally driving the rotating body 4a is provided substantially directly below the rotating body 4a,
An encoder 17 is fixed to one end of the rotating shaft of the rotary drive motor 12, and a gear 13 is fixed to the other end. The gear 13 is meshed with a gear 14 having a larger diameter than the gear 15, which is rotatably supported coaxially with the small diameter gear 15. via the gear 15
The rotating body 4a is rotated by transmitting the rotational driving force of the rotational driving motor 12 to the gear 1B meshing with the gear l1m and the gear l1m. Said gear 1
3.14.15.16 form a reduction gear train.

A rotary encoder is used as the encoder 17 described above, and the rotary encoder 17 outputs a pulse signal corresponding to the rotation speed of the motor 12. In this embodiment, the rotary encoder 17 outputs a pulse signal corresponding to the rotation speed of the motor 12. The rotational speed of the rotating body 4a is determined from the number of pulses per unit time, and the rotational position of the rotating body 4a is detected from the integrated value of the number of pulses per unit time. However, it is of course possible to use separate detection means for one-rotation speed detection and position detection.

A rotating body holding mechanism 21, which constitutes a part of the above-mentioned positioning means Z, is provided near the outer periphery of the rear side plate ll attached to the rotating body 4a, and the rotating body holding mechanism Zl is approximately Stopper arm 19 formed in an L-shape
, a photo interrupter 29, and a lock solenoid 25 as a holding/releasing means. The details of the above-mentioned configuration will be further explained as follows. That is, in FIG. 3, the guide edge ta of the stopper plate 18
b is formed by cutting out a part of the arcuate edge of the stopper plate 18. An elongated hole 19a is formed approximately at the center of the stopper arm 19 (i.e., a portion of the elbow) constituting the above-mentioned rotating body holding mechanism Zl.

One end of the pin 20 is fixed to the main body of the device, and the other end of the pin 20 is inserted. A roller 22 is rotatably attached to one end of the stopper arm 19 via a stopper pin 21 and is capable of engaging/disengaging with a retaining groove 18m formed in the stopper plate 18. A tension coil spring 23 is stretched between the stopper pin 21 and the aforementioned pin 2o. Further, a pin 27 is attached to the other end 24 of the stopper arm 19, and a hole is formed in the vicinity of the pin 27, and the pin 27 is connected to the lock solenoid 25. A connecting member 26 is pivotally attached to the hole, and the roller 22 is attached to the hole.
A spring 28 is attached that biases the stopper arm 19 so that the stopper arm 19 comes into contact with the outer peripheral portion of the stopper plate 18.

A photo-interrupter 29 is disposed near the end 24 of the stopper arm 19, and the photo-interrupter 29 has an opposing structure formed by a light-emitting element means and a light-receiving element means that constitute the photo-interrupter 29. When the interval is set such that the end 24 of the arm 19 can pass through when the stopper arm 19 moves, and the end 24 of the arm 19 is within the opposing interval. The light emitted from the light emitting element means toward the light receiving element means is blocked. The lock solenoid 25 is driven before rotating the rotating body 4a in a stopped state, and when excited, rotates the stopper arm 19 about the pin 20 via the connecting member 26, and Engagement groove 1
8a and the roller 22 are disengaged from each other.

When rotating the single rotating body 4a in the above-described configuration, as described above, first, the lock solenoid 25 is energized so that the engagement groove 18 and the roller 22 are rotated.
A process is required to disengage the When the engagement between the engagement groove 18 and the roller 22 is released as described above, the end of the stopper arm 19, which had been present within the opposing gap of the photo ink clubter 29, moves into the opposing gap. Therefore, the light from the light emitting element means that was blocked by the end portion 24 is irradiated toward the light receiving element means, thereby preventing the light receiving element means from engaging with the engagement groove 1ga roller 22. A signal indicating that the connection has been released will be output. Moreover, on the other hand, the above-mentioned rotating body 4
In order to stop the rotational drive of a, it is necessary to demagnetize the lock solenoid 25 before the stopper plate 1B reaches the position of the roller 22 mentioned above.

When the lock solenoid 25 is demagnetized before the stopper plate 18 comes to the position of the roller 22, the roller 22 rotates along the arcuate edge of the stopper plate 18 rotating in the N direction in FIG. , is guided to the engagement groove 18a via the guide edge 18b and engaged with the engagement groove 18a. The end portion 24 of the stopper arm 19 mentioned above is.

The moment the roller 22 enters the engagement groove 18a, it appears in the opposing gap, which is the optical path of the photointerrupter 29, thereby blocking the light that had been irradiated from the light emitting element means toward the light receiving element means. , so that the light receiving element means outputs a signal indicating that the roller 22 has engaged with the engagement groove 111m.

FIG. 4 shows a control system included in an image forming apparatus according to an embodiment of the present invention.0 An overview of a control system included in an image forming apparatus according to an embodiment of the present invention is shown in FIG. As is clear from the reference, there is a rotating body drive control circuit 31 that controls the rotary developing device shown in FIGS.
32). The rotating body drive control circuit 31 described above includes a motor control CPU 31d that controls the driver 30 for driving the rotational drive motor M12, a vector detection circuit 31a, a position counter 31b, a speed counter 31c, a timer 31f, and D. /A converter 31g. The vector detection circuit 31a described above receives input of two-phase pulses output from the rotary encoder 17 and outputs data regarding the forward and reverse rotational directions of the rotating body 4a. The position counter 3
1 employs an up/down counter, and the position counter 31b is connected to the vector detection circuit 31m.
The data regarding the forward and reverse rotation directions output from the rotary encoder 17 and the vector detection circuit 3 output from the rotary encoder 17
1a is input, and rotational movement position data based on the home position (HP) of the one-rotating body 4a is output to the motor control CPU 31d. The speed counter 31c is output from the rotary encoder 17 and is connected to the vector detection circuit 31.
input the pulse given through the rotating body 4a.
The rotational speed data is output to the motor control CPU 31d. The home position sensor xO is
As shown in FIG. 2, the reference position fiHP is located at 1. The home position sensor xO is based on the rotating body 4a! As mentioned above, we have reached IMP! When the J malfunction is detected, the position counter 31
A clear signal is output for b. The timer 31f clears the speed counter 31c and sets the cycle at which the motor control CPU 31d executes an interrupt program.
The timer 31f measures the set time set by the speed counter 31d and outputs a signal every time the set time elapses. 31c and the motor control CPU 31d.
The motor control CPU 31d is configured to cause the motor control CPU 31d to execute the interrupt program by outputting the above-mentioned signal to the interrupt terminal INT. or,
As is clear from the above-described content, the timer 31f is set and reset by the motor control CPU 31d. The motor control CPU 31d includes a ROM 31d+ and a RAM 31.
The ROM 31d1 contains data indicating the relationship between the rotation amount and the color mode that can be set from monochrome copy to four-color copy. Sometimes, data indicating the relationship between the amount of rotational movement and the rotational speed when moving the magenta developing device 54M to the developing position, when one developing device is at the developing position, another developing device is moved to the developing position. Data indicating the relationship between the amount of rotational movement and rotational speed required to move the object up to that point are stored as a control data table. The motor control CPU 31d executes the interrupt program when the timer 31f outputs the above-mentioned signal, and controls the speed counter 31c.
, reads speed data and position data from the position counter 31b, respectively, and stores both of the read data and the ROM 31d.
&D based on the control data table read from l.
The motor M12 is controlled via the /A converter 31g and the driver 30. The copying machine main body control circuit 32 described above is equipped with a sequence controller therein, and the sequence controller is connected to the motor control CPU via the I10 port and the load drive circuit.
The motor control CPU 31d is configured to be controlled by outputting a control signal to the motor control CPU 31d.

Next, let's look at the operation of the control system configured as described above.

This will be explained mainly with reference to the flowchart shown in FIG. When the operator turns on the drive power of the image forming apparatus and recognizes that a drive command has been given by manually operating the operation section of the apparatus, the copying machine main body control circuit 32 controls the motor control CPU 3.
A mode signal MO1M1.1d for specifying a start signal and a rotational position of the rotating body 4a. Output M2,
The motor control CPU 31d reads the 2@ signal (step 5-1). When the two types of signals are read in step S-1, the motor control CPU 31d reads the 2@ signal in advance according to the mode signal. The data stored in the ROM 31d and the data stored in the RAM 31dz are read out and arithmetic processing is performed according to the following process.

That is, the data on the number of pulses to be counted by the position counter 31b and the forced deceleration control at the time when the rotational speed control of the rotating body 4a, which is set according to the mode signal, is switched from servo control to forced deceleration control. Data on the number of pulses to be counted by the position counter 31b from the time when the rotational speed of the rotating body 4a reaches the lowest speed is stored in the ROM 3.
At the same time, the RAM 31 d reads data on the number of pulses counted by the position counter 31 b from the start of forced deceleration control during driving until the rotating body 4 a reaches its lowest speed. Read out the pulse number data from the start of deceleration to the lowest speed stored in ROM31 dl and RAM3
The difference value is calculated between the pulse number data from the start of deceleration to the lowest speed stored in the ROM31d+, and the pulse number data stored in the ROM31d+ is corrected by this difference value. The data after this is stored in the RAM 31 dl as pulse number data when switching the speed control from servo control to forced deceleration control during the current drive of the rotation body 4a (step 5-2).
, After storing the pulse number data as described above in the RAM 31 dz in step S-2, the motor control CP
U31d outputs a drive command signal to the lock solenoid 25 drive circuit to energize the lock solenoid 25 (step 5-3), and by energizing the lock solenoid 25 as described above in step S-3, Engagement of rotating body 4a * When it is recognized based on the signal output from the photo interrupter 29 that the engagement between l 8 a and the roller 22 is released and the rotating body 4a is in a rotatable state ( Step 5-4), C for motor control
The PU 31d outputs a drive command signal to the driver 30 via the D/A converter 31g, drives the motor M12, and the value of the position counter 31b reaches step S-2.
The servo control of the motor M12 as described above is continued until the count value of the position counter 31b matches the pulse number data set in the RAM 31 ctz (step 5-5). When it is confirmed that the data matches the pulse number data as described above (step 5-6), the motor control CPU 3
1d controls the rotational speed of the motor M12 in step S-5.
The servo control that has been executed is switched to a deceleration control that forcibly decelerates and shifts to the lowest speed (step 5-7), and the rotational speed of the rotating body 4a reaches the lowest speed according to the count value given from the speed counter 31c. When the position counter 3 is recognized (step 5-a), the position counter 3
Read the pulse number data at the time from 1b (
Step 5-9), Store this data in the RAM 31D2 as reference data for setting the start point of starting forced deceleration control of the motor M12 during the next drive (Step S-10), Step 5- After storing the reference data in the RAM 31 d as described above in step S-10, the rotating body 4a is driven to rotate at the minimum speed as described above to the developing position (step S-11);
When it is recognized based on the signal output from the photo interrupter 29 that the roller 22 and the retaining groove 18a are engaged (step S-12), the output of the drive command signal to the driver 30 is stopped. Step S-13), the rotating body 4 is
EH11 indicating that the rotational drive of a has ended is output (step S-14).

Through the process described above, the developer holding the developer of the color corresponding to the electrostatic latent image formed on the outer peripheral surface of the photoreceptor drum 2 completes its rotational movement to the development position, and the predetermined color is completed. Development will be performed.

As described above, according to the present invention, even if a load fluctuation occurs due to some reason in the developing means that can be circulated near the image carrier, the load fluctuation causes the developing means to It is possible to control the circulation speed so that it is not easily affected.

An image forming apparatus that can perform normal development can be provided.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the overall configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a partial perspective view of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a partially enlarged view of the configuration shown in FIG. 2. FIG. 4 is a block diagram showing the configuration of a control system included in an image forming apparatus according to an embodiment of the present invention. FIG. 5 is a flowchart showing the operation of the configuration shown in FIG. 4. 2: Photosensitive drums 4Y, 4M, 4C, 4BK: Developing device 4a: Rotating body 31d: CPU for motor control

Claims (1)

[Scope of Claims] 1) An image carrier, a developing means that is movable in circulation to a developing position for developing an electrostatic latent image formed on the image carrier adjacent to the image carrier, and the developing member. After the means reaches a position upstream of the preset developing position in the circulating movement direction and until it reaches the developing position, the circulating movement speed of the developing means is forcibly reduced. In the image forming apparatus, the control means controls a circulating movement speed of the developing means at a minimum speed and stops at the developing position, the controlling means forcibly controlling a preset circulating movement speed of the developing means. Data on the amount of circulation movement of the developing means from when the speed is decelerated to the lowest speed until the speed of circulation movement reaches the lowest speed; The detection value data of the circulating movement amount of the developing means up to the speed are respectively stored, and the preset circulating movement amount data is corrected based on the detected value data, and the corrected result is An image forming apparatus characterized in that the timing at which a forced deceleration of the circulating speed of the developing means is started is controlled accordingly. 2) The image carrier is rotatably supported, and
It is a photosensitive drum on which electrostatic latent images of multiple colors corresponding to document image information are formed on its outer peripheral surface, and the developing means includes a plurality of developing devices each holding a developer of a different color. The image according to claim 1, which is a rotary developing device including a plurality of developing devices and a rotating body rotatably supported. Forming device. 3) The circulating movement amount data of the developing means stored in advance in the control means is set for each of a plurality of image forming modes, as set forth in claim 1 or 2. image forming device. 4) The control means servo-controls the circulating movement speed of the developing means until the developing means reaches a position set upstream of the developing position in the circulation movement direction. An image forming apparatus according to any one of claims 1 to 3.