JP3268479B2 - Driving device for rotating image forming body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating body of an image output apparatus for forming an image in a digital manner by an electrophotographic system, and more particularly to a rotating body driving device for rotating a photosensitive body. Further, the present invention relates to a color image forming apparatus in which a plurality of developing units are arranged on a peripheral surface of an image forming body and a single color toner image is superposed to form a color toner image.

[0002]

2. Description of the Related Art In an electrophotographic copying machine, a printer, or the like, an electrostatic latent image is formed on the surface of a rotating cylindrical photoconductor or a belt-shaped photoconductor, and the formed electrostatic latent image is formed. The toner is attached to the latent image and developed, and the toner image is transferred and fixed on a recording paper to obtain an image.

Here, a cylindrical photosensitive member of an image output device,
That is, the photoconductor drum and the drive roller for driving the belt-shaped photoconductor are referred to as a rotating body.

If the speed of the rotating photosensitive member fluctuates due to some influence, jitter or image unevenness occurs in the output image. This is particularly noticeable in a digital electrophotographic technique in which writing on a photoconductor is performed by scanning a semiconductor laser. Fluctuations in the rotation speed of the photoconductor cause fluctuations in the sub-scanning direction of the writing system, resulting in a writing line. Causes a slight shift in the distance between the images, thereby causing a significant reduction in image quality.

In particular, in a color image forming apparatus in which a plurality of developing units are arranged on the peripheral surface of an image forming body and a single color toner image is superposed to form a color toner image,
Since the color tone of the secondary color formed by the two or more toner layers is determined by an appropriate amount of toner of each color of each layer, the position accuracy of each layer is strictly required. That is, the first mechanism in which the color tone changes is that, in the image forming process of the second and subsequent layers, the exposure by the semiconductor laser or the like is performed from above the toner layer already formed on the photoconductor,
When the position to be exposed on the toner layer is displaced by the effect of the speed fluctuation of the photoconductor, the surface of the photoconductor without the toner layer is exposed. At this time, since the surface potential of the photoreceptor is lower than when the toner layer is already present,
The amount of toner adhered after the development is larger than that on the toner layer. As a result, the color tone of this portion deviates from the target value. Further, as a second mechanism for changing the color tone, in a digital image output device, an image is often constituted by a line which is a continuous body of dots.
In this case, there is a difference in line or dot density between the portion where the exposure interval is narrowed and the portion where the exposure interval is widened due to the speed fluctuation of the photoconductor, and this results in color unevenness in the rotation direction of the photoconductor as an image. appear. This significantly degrades the quality of the color image.

On the other hand, in the design of a drive system of a conventional copier or a printer, the drive target is designed to satisfy the line speed, the number of revolutions, and the like derived from the product specifications while maintaining a proper relationship with the allowable space. Emphasis was placed on exploring the placement. In other words, how to transmit the power from the power source to the drive target and what to use as a mechanical element for power transmission have been of great interest. Therefore, when the unevenness and rotation unevenness occur in the finished product, the cause is searched for, the bearing of the drive shaft of the photoconductor is changed to a sintered product, the flywheel is connected to the drive shaft of the photoconductor,
Measures have been taken to mount a brake combining a spring and a friction member on the rotating shaft of the photoreceptor, improve gear accuracy, and use helical gears having various torsion angles.

[0007]

The main causes of the speed fluctuation of the driving system are the speed fluctuation per rotation of the rotating shaft of the motor and the large absolute value of the fluctuation component of one rotation component and one tooth component of the gear. It has been found that these fluctuation components and their harmonic components are amplified or cause a resonance phenomenon in relation to the natural frequency of the drive system.

FIG. 12 shows a speed fluctuation power spectrum of the drive system of the conventional machine. According to this, the fluctuation component due to one tooth of the gear based on the line speed inherent to the machine has 176 Hz for the gear directly connected to the motor, 64 Hz for the second shaft, and 25 Hz for the gear directly connected to the drum. As 50Hz
Things have appeared. Further, one rotation component of the gear directly connected to the motor has 22 Hz, and 44 Hz appears as a harmonic thereof.

FIG. 13 shows a measurement example of a transfer function for numerically obtaining the natural frequency of the drive system. In this case, the output of the impact vibration hammer and the output of the piezoelectric pickup sensor attached to one end of the photosensitive drum so as to measure the acceleration fluctuation in the rotation direction are connected to a dual-channel FET analyzer, and the respective Fourier sensors are connected. The measurement was performed by a method for determining the ratio of spectra. From this Figure 13,
It can be seen that the peak of the natural frequency of this drive system is around 45 Hz, and the region where the level of the transfer function is high spreads to around 30 to 60 Hz.

FIG. 14 shows a superposition of the fluctuation component spectrum and the transfer function. As you can see from this figure,
This drive system has a peak of a transfer function, a fluctuation component and its 2
The position of the frequency region where the second harmonic exists is overlapped. That is, it has been found that the present drive system is a system that amplifies the fluctuation component (resonates).

In fact, when the measured values of three machines having this drive system were examined, the rotation fluctuation of the photosensitive member showed a value of 5 to 8%.

The present invention has been made to solve the above problems. That is, the unevenness and the rotation unevenness of the rotating photoreceptor of the image output device which forms an image in a digital manner by the electrophotographic method are prevented, that is, the interval between the write lines in the sub-scanning direction is fixed, and the jitter and the image unevenness are prevented. It is an object of the present invention to provide a driving device for a rotating body capable of forming a high-quality image without any problem.

Another object of the present invention is to provide an image forming apparatus for forming a high-quality image free from density unevenness and color unevenness occurring in the rotation direction of a photosensitive member in a digital color image.

In order to solve the above-mentioned problems, the present invention is based on the premise that speed fluctuations at a source such as a motor or a gear are reduced, and further focuses on transmission of a fluctuation component through a drive transmission system. Then, the driving device of the rotating body is configured as follows in consideration of the concept of the transfer function, resonance, and natural frequency, and in consideration of how the transmitted fluctuation is attenuated.

First, in order to avoid resonance of the rotating body drive system, the natural frequency of the rotating body drive system and the frequency of the fluctuation component transmitted to the rotating body drive system are prevented from being matched.
In general, the natural frequency f _N is expressed by the following equation.

F _N = (1 / 2π) √ (K / I) (Equation 1) where K is the torsional rigidity of the drive system, and I is the moment of inertia. The value of f _N can be changed by changing the value of K or I to avoid resonance. To fluctuation component of the rotation drive system to f _N from the viewpoint of avoidance of resonance may be increased, or may be smaller. As a method for increasing the f _N, or to increase the K, it can be realized by reducing the I. Also, in order to reduce f _N ,
This can be realized by increasing I or decreasing K.

FIG. 15 and FIG. 16 show the data drive system shown in FIG.
As in FIG. 14, superposition is performed on the power spectrum of the rotation fluctuation of the drive system and the actually measured value of the transfer function when moved to a small value. FIG. 17 compares the peak values of the transfer functions for the above three drive systems. The structural change to reduce the rigidity of the drive system in FIG. 14 is to reduce the value of the torsional rigidity K of the drive system. By comparing the data of FIGS. 15, 16 and 17, it is conceivable that the torsional rigidity K of the drive system is reduced and the natural frequency is lowered in order to move the natural frequency to avoid resonance. In the case of a structural change to move to the frequency side, the transfer function decreases as the natural frequency moves. This is because the damping element becomes remarkable due to its flexible structure with the structural change for moving the natural frequency,
This is considered to be due to a shift to a structure in which the rotation fluctuation is absorbed by the drive system itself. As a result, when the natural frequency is moved to avoid resonance, a structural change to reduce the torsional rigidity K of the drive system is accompanied by a change in the magnitude of the transmission gain due to the change in the rotational speed. It turns out that it is advantageous and effective in reducing the speed fluctuation.

Accordingly, in the present invention, it is an object of the present invention to enable the driving member to transmit power to the rotating member without transmitting the rotation fluctuation by engaging the rotating member and the driving member with a low rigidity member. And

[0019]

An object of the present invention is to provide an image forming apparatus comprising: an image forming body; a driving gear for driving the forming support; and a driving mechanism including a driving motor and a plurality of gears connected thereto. In a rotating image forming apparatus driving device, which performs image formation in a digital manner in an electrophotographic system by rotating the image forming body from the mechanism via the driving gear, a leaf spring member or a protrusion member may be provided on the image forming body. A projection member or a leaf spring member is provided on the driving gear, and the driving gear is pressed against each other, and a driving force from the driving gear is transmitted to the image forming body via the pressing portion. Achieved by the device.

[0020]

By reducing the rigidity K of the rotating body drive system, the natural frequency of the rotating body drive system represented by the equation (1) is reduced, so that the natural frequency and the fluctuation component in the frequency domain can be separated. Rotational speed fluctuations can be reduced by preventing resonance of the drive system. Further, when the rigidity of the rotating body drive system is reduced, the transmission gain of the rotating body drive system can be reduced by achieving the flexible structure, and the level of speed fluctuation in rotating body drive can be reduced. As a result, the speed fluctuation of the rotating body can be reduced, and the quality of the output image can be greatly improved. Further, the size of the apparatus can be reduced, the cost can be reduced, and the reliability of the entire system can be improved.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of each embodiment of the present invention, the structure and operation of a color image forming apparatus using the above-mentioned rotating member, that is, an image forming member, will be described.

In FIG. 1, reference numeral 10 denotes a photosensitive drum which is an image forming member, which is formed by applying an OPC photosensitive member on the drum, is grounded, and is driven to rotate clockwise. 12 is a scorotron charger, a uniform charging of the V _H the photosensitive drum 10 peripheral surface is provided by a corona discharge by a grid and the corona discharge wire which is the potential held in the V _G. Prior to charging by the scorotron charger 12, a PCL using a light emitting diode or the like is used to eliminate the history of the photoconductor until the previous printing.
Exposure by 11 is performed to remove static from the peripheral surface of the photoconductor.

After the photosensitive member is uniformly charged, the image exposure means 13 performs image exposure based on the image signal. Image exposure means
Reference numeral 13 denotes a reflection mirror 1 via a polygon mirror 131 rotating with a laser diode (not shown) as a light source, an fθ lens, and the like.
The optical path is bent by 32 to perform scanning, and a latent image is formed by rotation (sub-scan) of the photosensitive drum 10.
In the present embodiment, a character portion is exposed to form a reversal latent image such that the character portion has a lower potential _VL .

The periphery of the photosensitive drum 10 has a yellow (Y)
Developing devices each containing a built-in developer composed of toner and carrier such as magenta (M), cyan (C), black (K), etc.
First, development of the first color is performed by a developing sleeve 141 which rotates with a built-in magnet and holding a developer. The developer is a carrier coated with an insulating resin around a ferrite core, a pigment and a charge control agent according to the color with polyester as the main material,
It is composed of a toner to which silica, titanium oxide or the like is added, and the developer is applied onto the developing sleeve 141 by a layer forming means.
It is conveyed to the development area while being regulated to a layer thickness (developer) of 00 to 600 μm.

The gap between the developing sleeve 141 and the photosensitive drum 10 in the developing area is 0.2 to 0.2, which is larger than the layer thickness (developer).
As 1.0mm, D of the AC bias and V _DC of V _AC during this time
A C bias is superimposed and applied. V _DC and V _H, for charging the toner are the same polarity, the toner given the opportunity to leave from the carrier by V _AC is not adhere to a portion of the high V _H of potential than V _DC, potential than V _DC Adhered to the low V _L portion, and visualization (reversal development) is performed.

After the visualization of the first color is completed, the image forming process for the second color is started, and the uniform charging is again performed by the scorotron charger 12, and a latent image based on the image data of the second color is formed by the image exposure means 13. Is done. At this time, the charge removal by the PCL 11 performed in the image forming process of the first color is not performed because the toner attached to the image portion of the first color scatters due to a sharp drop in the surrounding electric potential.

Again, V is applied over the entire peripheral surface of the photosensitive drum 10.
A latent image similar to that of the first color is formed and developed on a portion of the photoconductor having the potential of _H where there is no image of the first color. the part for a latent image of V _M 'is formed by the charge possessed by the shading of the toner itself by the toner adhering the first color, V _DC
And development according to the potential difference between V _M ′ and V _M ′. In the overlapping portion of the first color image and the second color image, the development of the first color is performed by V _L
When the latent image of the first color is formed, the balance between the first color and the second color is lost, so that the exposure amount of the first color is reduced and V _H > V _M > V
_It may be an intermediate potential that becomes _L.

For the third color and the fourth color, the same image forming process as that for the second color is performed, and a visible image of four colors is formed on the peripheral surface of the photosensitive drum 10.

On the other hand, the recording paper conveyed from the paper supply cassette 15 via the half-moon roller 16 stops temporarily, and is supplied to the transfer area by the rotation of the paper supply roller 17 when the transfer timing is adjusted.

In the transfer area, a transfer roller 18 is pressed against the peripheral surface of the photosensitive drum 10 in synchronization with the transfer timing.
A multicolor image is collectively transferred by sandwiching the fed recording paper.

Next, the recording paper is destaticized by the separation brush 19 almost simultaneously pressed and separated by the peripheral surface of the photosensitive drum 10 and conveyed to the fixing device 20, where the heat roller 201 and the pressure roller 202 are heated and pressed. After the toner is fused, the toner is discharged to the outside of the apparatus via the paper discharge roller 21. The transfer roller 18 and the separation brush 19 are retracted and separated from the peripheral surface of the photosensitive drum 10 after the recording paper has passed to prepare for the formation of the next toner image.

On the other hand, the photosensitive drum 10 from which the recording paper is separated is
The residual toner is removed and cleaned by pressing the blade 221 of the cleaning device 22, and the charge is removed again by the PCL 11 and the charger.
The next image forming process is started after receiving the charge by the step 12. The blade 221 moves immediately after the cleaning of the photoconductor surface and retreats from the peripheral surface of the photoconductor drum 10.

The function and performance characteristics of each device constituting the image forming section of the above-described apparatus will be described below.

(Photoreceptor) The photoreceptor drum 10 realizes a uniform charging operation by the above-mentioned scorotron charger 12 on the peripheral OPC photoreceptor by a stable rotation operation. At the time of charging, the grid potential is controlled to stabilize the charging potential.
The specifications of the photoreceptor and the charging conditions thereof are set as follows as an example.

Photosensitive material: OPC φ120 Linear velocity 100 mm / sec Negative charging Charging condition: Charging wire: Platinum wire (cladding or alloy) is preferably used. _VH- 750V, _VL- 50V (Image exposure) FIG. 2A is a plan view and a side view of the layout of the image exposure means 13, and FIG. 2B is a semiconductor laser unit used for the image exposure means 13. It is explanatory drawing of 135.

After the OPC photosensitive member on the peripheral surface of the photosensitive drum 10 is negatively charged by the charger 12, the photosensitive member is exposed to light emitted from the semiconductor laser unit 135 of the image exposure means 13 to form an electrostatic latent image.

Image data from a formatter for decoding printer commands is sent to a laser diode (LD) modulation circuit, and when the LD of the semiconductor laser unit 135 emits light according to the modulated image signal, the beam light is transmitted to the mirror 1.
Each scanning line is synchronized by a beam index 136 via 32 and projected onto a polygon mirror 131.

The polygon mirror 131 reflects the light beam on the polyhedron and scans the light beam. After the light beam is corrected by the fφ lens 133 and the cylindrical lens 134, the polygon mirror 131 exposes the photosensitive member via the reflection mirror 132 to expose the photosensitive member. A main scan is performed to form an electrostatic image.

The beam system of the laser light is narrowed down to 600 DPI by the optical system. Therefore, in order to obtain a high quality image, it is necessary to reduce the particle size of the toner. In this embodiment, a toner having a size of 8 μm is used for each color. However, what matters most to users is the quality of black text,
The black toner is preferably a small particle size toner (7 μm to 11 μm).

As an optical system for image exposure, for example, one having the following configuration is used.

The polygon mirror 6 side, the rotational speed 23600rpm air bearing adopted lens focal length: f = 140 mm preparative Bu Ttokurokku: 20MH ₂ bi chromatography beam diameter: about 60 × 80 [mu] m (now the image) Figure 3 shows the configuration of the developing unit 14 The toner supplied from the toner box is dropped to the right end of the developing device, is stirred and mixed with the carrier by a pair of stirring screws 142 rotating in opposite directions, and has a predetermined charge amount (Q / M). Is set to

The stirred two-component developer is supplied to a supply roller 143.
Is transported to the developing sleeve 141 through the
Is transported to the developing area of the photoreceptor drum 10 by reverse development of the electrostatic latent image under the following developing conditions.

Current image gap: 0.5 mm Toner Conveyance: 20 to 30 mg / cm ² Developing bias (AC): 2 KV, 8 KH ₂ (DC): -650 V Developing sleeve rotation direction: Positive to photosensitive drum Adjustment of transferred image density: Controlling the number of rotations of the developing sleeve or controlling the developing bias (a patch image is formed on the photoreceptor by a laser beam, the reflection density is measured after development, and the image density is adjusted). I do.

The above-described patch image P is formed by performing exposure and development for each color outside the image area of the photosensitive drum 10 each time a predetermined number of prints are completed.

FIG. 4 shows a patch image P formed for each color.
As shown in (a), the reflectance, that is, the image density is detected by each patch detection unit 100 located on the downstream side of the rotation of the photosensitive drum 10 of each developing device 14, and the detection signal is converted into an output voltage by a detection circuit. Then, it is input to a control logic circuit that controls the bias voltage of the developing bias.

The patch detection unit 100 is shown in FIG.
As shown in FIG. 3B, the light-emitting unit 101 includes a light-emitting unit 101 composed of an LED and a light-receiving unit 102 composed of a phototransistor. And sends a detection signal to the detection circuit.

The above-described detection signal is input as an output voltage Vout to the control logic circuit of the developing bias by the processing of the detecting circuit shown in FIG. 5, and the image density is controlled by controlling the developing bias applied to each developing sleeve 141. Make adjustments.

The photosensitive drum 10 is driven and rotated by a driving device shown in FIG. The driving device is composed of a driving motor M and a gear group G connected to the driving motor M. A driving gear 30, which is the final gear of the gear group G, transmits power directly to the photosensitive drum 10 or is fixed to an end face. Power is transmitted indirectly via 40.

(Embodiment 1) An embodiment of the present invention will be described with reference to FIGS.

The photosensitive drum 10 has a pair of projecting portions 10A integrally formed at symmetrical positions about the center of rotation of the end face, and a pair of leaf spring members 10B are fixed to the side portions thereof by screws.

The leaf spring member 10B has a predetermined elasticity at the tip portion bent in a U-shape, and is held in a symmetrical posture by the protrusion 10A.

On the other hand, the drive gear 30 has a pair of pressing pins 30P as projecting members projecting at symmetrical positions about the center of rotation of the side face facing the end face of the photosensitive drum 10, and the respective tips of the leaf spring members 10B. We are facing the department.

When the photosensitive drum 10 and the driving gear 30 are assembled at a predetermined position and the driving gear 30 is driven in the direction indicated by the arrow, each of the pressing pins 30P comes into contact with the distal end of the leaf spring member 10B. In contact with the photosensitive drum 10, the leaf spring member 10B is pressed and elastically deformed according to the magnitude of the load on the photosensitive drum 10 to transmit power and rotate the photosensitive drum 10 in the direction indicated by the arrow.

When transmitting power, the above-described leaf spring member 10B is used.
Absorbs temporary or steady fluctuations in the impact, driving force, and driving speed of the driving gear 30, and as a result, the photosensitive drum 10
Is always rotated at a constant speed to form a high quality image.

The same effect can be obtained by using a flat plate-like leaf spring member 10D as shown in FIG. 8 instead of the above-mentioned leaf spring member 10B.

The leaf spring member 10D is sandwiched and held by two pairs of support pins 10C.
Drive gear that bends in an arc shape and is elastically deformed by pressing 30P
Absorbs shocks and others generated on the 30 side.

(Embodiment 2) FIG. 9 shows a second embodiment of the present invention.
And FIG.

The photosensitive drum 10 is provided with a pair of pressing pins 10P as projecting members at symmetrical positions about the center of rotation of the end face, while the drive gear 30 is provided at the center of rotation of the side face facing the end face of the photosensitive drum 10. A pair of projecting portions 30A are formed at symmetrical positions, and a pair of leaf spring members 30B are fixed to the side portions thereof by screws.

The leaf spring member 30B has a U-shaped bent end portion having a predetermined elasticity, is held in a symmetrical posture by the protruding portion 30A, and each end portion is connected to the engaging pin 10P. Each is facing.

When the photosensitive drum 10 and the driving gear 30 are assembled at a predetermined position and the driving gear 30 is driven in the direction indicated by the arrow, each leaf spring member 30B has its distal end at each pressing pin 10
The photosensitive drum 10 is elastically deformed by pressing in accordance with the load on the photosensitive drum 10 to transmit power, and rotates the photosensitive drum 10 in the direction indicated by the arrow.

When transmitting power, the above-described leaf spring member 30B is used.
Absorbs temporary or steady fluctuations in the impact, driving force, and driving speed of the driving gear 30, and as a result, the photosensitive drum 10
Is always rotated at a constant speed and load to form a high quality image.

The same effect can be obtained by using a flat plate-like leaf spring member 30D as shown in FIG. 10 instead of the above-described leaf spring member 30B.

The leaf spring member 30D is sandwiched and held by a pair of support pins 30C, and is curved and elastically deformed by the pressing of the photosensitive drum 10 against the pressing pin 10P, and is generated on the driving gear 30 side. Absorb other shots.

For the leaf spring members 10B and 30B described above, the material is SUS301-CSP-1-1 / 2H, and the shape and dimensions and the position with respect to each pressing pin 30P or 10P are set as shown in FIG. It has been confirmed by experiments that the required spring characteristics can be obtained.

In each of the above embodiments, the object to be driven is limited to the drum-shaped photosensitive member. However, in the first and second aspects of the present invention, a belt-shaped photosensitive member is used in addition to the drum-shaped photosensitive member. A rotating body used for conveyance, a so-called rotating roller, is also included in the drive target.

FIG. 18 shows this embodiment. A charging device 312 and a plurality of developing devices 314 containing different color toners are provided around the periphery of a belt photoreceptor 310 having a photoreceptor provided on a belt. ,
A transfer unit 318 and a cleaning unit 322 are provided. The belt photoconductor 310 is stretched between a driving roller 320A and a driven roller 320B and rotates clockwise in FIG.
After charging by a charger 312, a latent image is formed by scanning with an exposure unit 313 using a laser,
14 to develop a toner image. By repeating such an image forming process a plurality of times, a multicolor toner image is superimposed on the belt photoconductor 310. The superimposed toner image is transferred onto a separately fed recording sheet by a transfer unit 318, and the recording sheet is separated and then fixed. Also in a color image forming apparatus using such a belt-shaped photoconductor, by applying the driving device according to the present invention between the driving source and the driving roller 320A, the same effect as that described in the previous embodiment can be obtained. Can be

[0067]

According to the present invention, the photoreceptor is always rotated at a stable speed by minimizing the influence of a change in the load or fluctuation of the driving force of the driving system. Thus, there has been provided an image forming body capable of forming an image having both excellent color tones and a driving apparatus for a rotary image forming body for driving the image forming body.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an image forming apparatus including a rotary image forming body driving device according to the present invention.

FIG. 2 is an explanatory diagram of an image exposure unit of the apparatus.

FIG. 3 is a sectional view of a developing device of the apparatus.

FIG. 4 is an explanatory diagram of image density control in the apparatus.

FIG. 5 is a control circuit diagram.

FIG. 6 is a perspective view showing a driving system of a rotating body.

FIG. 7 is an explanatory diagram of a driving method (first example).

FIG. 8 is an explanatory diagram of a driving method (second example).

FIG. 9 is an explanatory diagram of a driving method (third example).

FIG. 10 is an explanatory diagram of a driving method (fourth example).

FIG. 11 is a view showing the shape and dimensions of a leaf spring member.

FIG. 12 is a graph showing a power spectrum of a speed variation of a conventional photoconductor.

FIG. 13 is a graph showing a transfer function of a conventional photoconductor driving system.

FIG. 14 is a graph showing a speed variation power spectrum of a conventional photoconductor and a transfer function of a photoconductor drive system.

FIG. 15 is a graph showing the transfer function of the photosensitive member drive system and the speed fluctuation power spectrum of the photosensitive member when the natural frequency is increased.

FIG. 16 is a graph showing the transfer function of the photosensitive member drive system and the speed fluctuation power spectrum of the photosensitive member when the natural frequency is reduced.

FIG. 17 is a graph showing a peak value of a transfer function of each drive system.

FIG. 18 is a cross-sectional view illustrating another embodiment of the image forming apparatus provided with the driving device for the rotary image forming body of the present invention.

[Explanation of symbols]

 10 Photoreceptor drum 10A, 30A Projection 10B, 10D, 30B, 30D Leaf spring member 10C, 30C Support pin 10P, 30P Press pin 30 Drive gear

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-228281 (JP, A) JP-A-57-151955 (JP, A) Japanese Utility Model No. 2-109357 (JP, U) Japanese Utility Model Application No. 4- 24152 (JP, U) Actually open 63-86464 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 21/00 350

Claims (1)

(57) [Claims] An image forming body, a driving gear for driving the forming carrier, and a driving mechanism including a driving motor and a plurality of gears connected to the driving motor, wherein the driving mechanism includes a driving gear via the driving gear. A driving device for a rotary image forming body that performs image formation in a digital manner in electrophotography by rotating the image forming body, wherein the image forming body includes a leaf spring member or a projection member, and the driving gear includes a projection member or a leaf spring. A driving device for a rotating image forming body, wherein members are provided and pressed against each other, and a driving force from the driving gear is transmitted to the image forming body via the pressing portion.