JP2007065052A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus designed such that moire caused by overlap of two bandings, resulting from a mechanical impact on an image, is made less likely to occur and an image of high image quality can be formed. <P>SOLUTION: The value of a frequency f1 which is the rate at which a development drive gears 52, namely a main body side development drive gear, engages and the value of a brush contact frequency f2 which is the rate at which the bristles of a photoreceptor cleaning roller 62 comes into contact with a photoreceptor 1 are made different so that the one is 10[%] or more higher than the other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a FAX.

In this type of image forming apparatus, for example, light is irradiated on an image carrier uniformly charged by a charging unit based on image data by an exposure unit to form an electrostatic latent image on the image carrier. Then, toner is supplied to the electrostatic latent image on the image carrier by the developing means to form a toner image. After the toner image on the image carrier is transferred to a transfer material by a transfer unit, the toner on the transfer material is heated and pressed by a fixing device to be fixed. After the transfer, the surface of the image carrier is untransferred by the cleaning unit after the transfer residual toner is removed by the cleaning unit. As this cleaning means, a cleaning device including a brush roller is known.
Conventionally, when the dot period or divisor of the halftone dot pattern of the image does not match the period of density change by the pixel clock, so-called moiré appears in which the density change is emphasized by the least common multiple of the two periods. There was a bug that it was.
In order to deal with such problems, Patent Document 1 prevents the occurrence of moire by performing control to change the cycle of the pixel clock according to the type of halftone dot pattern.

Japanese Patent Application Laid-Open No. 6-278731

However, it has been found that due to the recent trend toward higher image quality, the allowable range of density unevenness required for images has become stricter, resulting in periodic density changes on the image. As a result of intensive studies by the present inventors on this periodic change in density, it was found that two bandings resulting from mechanical impacts overlap and moire is generated.
Hereinafter, two bandings that cause moire will be described.

  In an image forming apparatus, a developer carrier is generally driven to rotate by transmitting a driving force input from the apparatus body through a plurality of gears. When a plurality of gears rotate while meshing with each other, minute impacts are generated by the meshing of teeth with each other. This periodic impact is called a meshing impact, and the number of times that this meshing impact occurs per second is called a meshing frequency. This meshing impact is transmitted to the image carrier via the developer carrier, and the linear velocity on the surface of the image carrier fluctuates periodically although it is minute. As a result, so-called banding (hereinafter referred to as first banding) in which the toner density, the lighter portion, and the darker portion are repeated at a predetermined pitch width occurs on the image transferred to the transfer material.

  On the other hand, a brush roller such as an image carrier cleaning brush roller that rotates with the bristles in contact with the image carrier has a period although the linear velocity of the image carrier is small due to an impact when the bristles contact the image carrier. Fluctuates. As a result, so-called banding (hereinafter referred to as second banding) occurs on the image transferred to the transfer material.

When the pitch width of the first banding and the pitch width of the second banding are close to each other, a periodic density change becomes conspicuous due to so-called moire in which the first banding and the second banding appear to overlap each other.
Conventionally, banding due to impact transmitted to the image carrier has been studied, but moiré images in which density changes are emphasized due to overlapping banding due to impact have not been studied.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus capable of forming a high-quality image without causing banding moire on an image. That is.

In order to achieve the above object, the invention of claim 1 transmits an image carrier and a developer carrier that develops a toner image on the image carrier and a driving force input to the developer carrier. An image forming apparatus comprising: a developing device having a plurality of development drive transmission gears; and a brush roller rotating with hairs contacting the image carrier. The meshing frequency of the development drive transmission gear on the main body side that transmits the drive to the brush, and the brush contact frequency determined by the product of the number of hairs growing in the circumferential direction of the roller of the brush roller and the rotation speed of the brush roller The difference obtained by subtracting the smaller value from the larger frequency value is 10% or more of the smaller frequency value.
According to a second aspect of the present invention, an image carrier, a developer carrier that develops a toner image on the image carrier, and a plurality of development drive transmission gears that transmit input driving force to the developer carrier. And a brush roller that rotates when hair contacts the image carrier, and is provided on a rotation shaft of the developer carrier among the development drive transmission gears. For the meshing frequency of the final development drive transmission gear and the brush contact frequency obtained by multiplying the number of hairs growing in the circumferential direction of the roller of the brush roller by the number of rotations of the brush roller, from the one with the larger frequency value The difference obtained by subtracting the smaller value is 10% or more of the smaller value of the frequency.
According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the brush roller is an image carrier cleaning brush for cleaning residual toner on the image carrier. .
According to a fourth aspect of the present invention, in the image forming apparatus according to the first, second, or third aspect, the pitch on the image according to the meshing frequency of the main body side development drive gear or the final development drive transmission gear is 0.5 [mm]. It is characterized by being smaller.
According to a fifth aspect of the present invention, in the image forming apparatus of the first, second, or third aspect, the pitch on the image according to the meshing frequency of the main body side development drive gear or the final development drive transmission gear is 2.0 [mm]. It is characterized by being larger.

  In the image forming apparatus according to any one of claims 1 to 5, at this time, the meshing frequency of the main body side development driving gear or the final development driving transmission gear and the brush contact frequency are separated by 10% or more of the smaller value. Therefore, the pitch width of the first banding and the pitch width of the second banding are also separated by 10% or more of the smaller value. If the difference between the two banding frequencies is 10% or more with respect to the value of the smaller frequency, the pitch width is less likely to cause more moire. Therefore, moire between the first banding and the second banding hardly occurs on the image.

  According to the first to fifth aspects of the present invention, there is an excellent effect that it is possible to provide an image forming apparatus capable of forming a high-quality image without causing banding moire on an image.

Hereinafter, an embodiment in which the present invention is applied to a tandem type color printer (hereinafter referred to as a printer 200) as an image forming apparatus will be described. FIG. 1 is a schematic configuration diagram illustrating an internal configuration of the printer 200.
As shown in FIG. 1, the printer 200 includes photosensitive drums 1Y and 1C that are image carriers on which toner images of colors of yellow (Y), cyan (C), magenta (M), and black (K) are formed. 1M, 1K. Hereinafter, the subscripts Y, M, C, and K of the respective symbols indicate members for yellow, cyan, magenta, and black, respectively. The toner images formed on the photosensitive drums 1Y, 1C, 1M, and 1K are primarily transferred to the intermediate transfer belt 2 at a predetermined timing, and a four-color superimposed toner image is formed on the intermediate transfer belt 2. The four-color superimposed toner image on the intermediate transfer belt 2 is fed at a predetermined timing from the paper feed cassette 4 by the registration roller pair 7 at the nip portion between the intermediate transfer belt 2 and the transfer roller 3. Is transcribed. The transfer material 8 onto which the toner image has been transferred is discharged onto the paper discharge tray 10 after the toner image is fixed by the fixing device 9.

Around the photosensitive drums 1Y, 1C, 1M, and 1K, a charging device (not shown) that charges the surface of each photosensitive drum 1, and an electrostatic latent image formed on the surface of each photosensitive drum 1 is developed to form a toner image. Developing devices 5Y, 5C, 5M, and 5K are provided. Further, cleaning devices 6Y, 6C, 6M, 6K, etc. are provided for cleaning the surface of each photosensitive drum 1 after the toner image is transferred to the intermediate transfer belt 2.
For example, the photosensitive drum 1Y for yellow is uniformly charged by a charging device, and an electrostatic latent image is formed by irradiation with laser light modulated based on image data by an exposure device (not shown). The electrostatic latent image on the photosensitive drum 1Y is developed with toner carried on the developing sleeve 51 of the developing device 5Y. The toner image developed on the photosensitive drum 1Y is transferred to the intermediate transfer belt 2. After the toner image is transferred, the surface of the photosensitive drum 1Y is cleaned of the transfer residual toner by the cleaning brush roller 61 of the cleaning device 6Y, and is prepared for the next image formation. Similarly, toner images are formed on the other photosensitive drums 1C, 1M, and 1K.

  The photosensitive drums 1Y, 1C, 1M, and 1K, the developing devices 5Y, 5C, 5M, and 5K, and the cleaning devices 6Y, 6C, 6M, and 6K are integrally formed as process cartridges 100Y, 100C, 100M, and 100K. Composed. When attaching / detaching the process cartridge 100Y from the apparatus main body, it is possible to attach / detach all of the photosensitive drum 1Y, the developing device 5Y, and the cleaning device 6Y with one operation.

  Further, the cleaning device 6 may be provided with a lubricant supply means for supplying a lubricant to the photosensitive drum 1. By providing the lubricant supply means, it is possible to reduce the friction coefficient of the surface of the photosensitive drum 1 to prevent the occurrence of toner filming, and to improve the transfer efficiency and the cleaning property of the adhered matter such as residual toner.

  Next, features of the printer according to the present embodiment will be described. FIG. 2 is a schematic side view showing the internal structure of the process cartridge. FIG. 3 is a schematic perspective view showing the internal structure of the process cartridge. The process cartridges 100Y, 100C, 100M, and 100K have the same configuration except that the toner colors to be used are different, and therefore, the process cartridge 100 will be described with the suffix omitted.

As shown in FIGS. 2 and 3, in the developing device 5, the driving force from the developing drive gear 52, which is an apparatus main body side development driving gear provided on the main body side, is transmitted by the final development driving transmission gear via the idler gear 53. It is transmitted to a certain developing sleeve gear 54. Then, the developing sleeve 51 provided coaxially with the developing sleeve gear 54 rotates to perform development on the photosensitive drum 1.
In the cleaning device 6, a driving force is input by a photoconductor cleaning drive joint 63 provided on the apparatus main body side, and the photoconductor cleaning brush roller 62 rotates through the driven joint 64 to clean the photoconductor drum 1. Is called. In the cleaning device 6, the photosensitive member cleaning drive joint 63 and the photosensitive member cleaning brush roller 62 are arranged so as to be coaxial with each other, and driving is directly input to the photosensitive member cleaning brush roller 62. May be driven indirectly.

  The process cartridge 100 is mounted in the apparatus main body while being positioned based on the shaft 1a of the photosensitive drum and the slave reference 110 provided on the side plate of the process cartridge 100. The shaft 1a of the photosensitive drum 1 and the shaft of the developing sleeve 51 are respectively supported by the face plate 50, and the shaft between the photosensitive drum 1 and the developing sleeve 51 is provided on the shaft 1a and the face plate 50 of the photosensitive drum 1. It is determined based on the subordinate standard 55.

FIG. 4 is a configuration diagram showing a configuration of a gear in the developing device. As shown in FIG. 4, when the rotation speed of the development drive gear 52 is T1 [rpm] and the number of teeth is t1 [teeth], the meshing frequency f1 [Hz] of the development drive gear 52 is expressed by the following equation (1). become.
f1 = T1 / 60 × t1 (Hz) (1)
Here, the developing drive gear 52, idler gear 53, which gears also meshing frequency order developing sleeve gear 54 is a series of gear train becomes f1.
Further, when the meshing frequency component f1 of the developing drive gear 52 becomes a vibration source and propagates to the photosensitive drum 1, the linear velocity of the photosensitive drum 1 periodically varies, and the pitch width x1 [mm] on the image is changed. Appears as 1 banding. The pitch width x1 is expressed by the following equation (2) when the linear velocity of the photosensitive drum 1 is V [mm / sec].
x1 = V / f1 = 60 × V / (t1 × T1) [mm] (2)

5A and 5B are schematic views of the photoconductor cleaning brush roller 62. FIG. 5A is a perspective view and FIG. 5B is a cross-sectional view.
As shown in FIG. 5, the photosensitive member cleaning brush roller 62 has hairs 61 planted uniformly in the circumferential direction. When the rotational speed of the photoconductor cleaning brush roller 62 is T2 [rpm] and the number of hairs in the circumferential direction is n [lines], the brush contact frequency f2 [Hz] at which the hairs contact the photoconductor is expressed by the following formula ( It becomes like 3).
f2 = T2 / 60 × n [Hz] (3)

In the photoconductor cleaning brush roller 62 shown in FIG. 5, the hairs 61 are aligned in the axial direction. However, the hairs 61 are shifted stepwise from the pile winding boundary 66 in the axial direction of the photoconductor cleaning brush roller 62. It does not matter.
Since the number of hairs 61 that simultaneously contact the photosensitive member is small due to the difference in height between the hairs 61, the effect of banding is reduced compared to the case where the arrangement of the hairs 61 is a straight line along the axial direction. . Even if the bristles 61 are uneven, if attention is paid to each row in the circumferential direction, the number of bristles 61 arranged in one circumference of the roller is the same, so the phase of the timing of contact with the photoconductor is different. The frequency is the same in every row. Therefore, the brush contact frequency can be considered in the same manner regardless of whether the hairs 61 are linearly arranged in the axial direction or arranged in a different manner.

Further, when the bristles 61 of the photoconductor cleaning brush roller 62 come into contact with the photoconductor drum 1, the linear velocity of the photoconductor drum 1 is periodically changed to form a banding having a pitch width of 2 mm on the image. appear. The pitch width x2 is expressed by the following equation (4) when the linear velocity of the photosensitive drum 1 is V [mm / sec].
x2 = V / f2 = 60 × V / (n × T2) [mm] (4)

By the way, when the photosensitive drum 1, the developing device 5, and the cleaning device 6 are integrally configured as in the process cartridge 100, vibrations are easily transmitted to each other, and the first banding and the second banding are simultaneously performed. Is likely to occur. On the other hand, if the difference between the meshing frequency f1 of the developing drive gear 52 and the brush contact frequency f2 of the bristles 61 of the photosensitive member cleaning brush roller 62 is small, the pitch width x1 of the first banding and the pitch width x2 of the second banding. The difference with is small. As a result, banding is emphasized by moire in the image formed on the transfer material 8.
Therefore, in this embodiment, the difference between the meshing frequency f1 of the developing drive gear 52 and the brush contact frequency f2 of the bristles 61 of the photoconductor cleaning brush roller 62 is 10% or more with respect to the smaller value. Like that.
In general, the developing device 5 or the cleaning device 6 is configured so that two frequencies are separated from each other by ± 10 [%] or more, which is considered to be less likely to generate moire, so that occurrence of banding emphasized by moire can be suppressed. .

  FIG. 6 is a characteristic diagram showing the relationship between the difference between the meshing frequency f1 and the brush contact frequency f2 and the degree of occurrence of moire. Table 1 is a table showing the relationship between the difference between the meshing frequency f1 and the brush contact frequency f2 and the moire state. As shown in FIG. 6 and Table 1, when the difference between the meshing frequency f1 and the brush contact frequency f2 is less than ± 10 [%], it can be seen that the occurrence of moire increases and banding becomes conspicuous. .

In order to set the difference between the meshing frequency f1 and the brush contact frequency f2 to ± 10 [%] or more, the developing device 5 and the cleaning device 6 may be configured by the following method, for example.
By changing the number of teeth of the developing sleeve gear 54 of the developing device 5 and changing the rotational speed T1 of the developing drive gear 52, the meshing frequency f1 of the developing drive gear 52 while keeping the rotational speed of the developing sleeve 51 constant. To change.
Specifically, when the number of rotations of the developing sleeve 51 is constant and the number of teeth of the developing sleeve gear 54 is increased, the meshing frequency of the developing sleeve gear 54 increases, and the meshing frequency of the developing drive gear 52 meshed in series therewith. f1 also increases. Accordingly, if the number of teeth t of the development drive gear 52 is constant, the rotation frequency T1 of the development drive gear 52 is increased, whereby the meshing frequency f1 can be changed with the rotation speed of the development sleeve 51 kept constant.
If the rotation speed of the developing sleeve 51 can be changed, this may be changed.

Further, by reducing the number n of the bristles 61 in the circumferential direction of the photoconductor cleaning brush roller 62 of the cleaning device 6, the bristles 61 are attached to the photoconductor drum 1 while the rotation speed T2 of the photoconductor cleaning brush roller 62 is kept constant. The contact brush frequency f2 can be reduced.
If the rotation speed of the photoconductor cleaning brush roller 62 can be changed, this may be changed.

In order to reduce the influence of banding, it is possible to change the module of the gear itself or change the rotation speed of the gear in order to reduce vibration. However, a change in the gear module and a change in the number of rotations of the gear also have an effect on other members, and a large configuration change is required.
Therefore, in addition to reducing the vibration itself, we will consider what reduces the effect of banding on the image.

Next, the relationship between the spatial frequency and the visibility of banding will be described.
FIG. 7 is a characteristic diagram showing the relationship between the spatial frequency and the visibility of banding. As shown in FIG. 7, the relationship between the spatial frequency and the visibility of the banding is in the range of the spatial frequency of about 0.5 to 2.0 [lines / mm] (NG region in the figure) due to human visual characteristics. It is said that this change is easily noticeable. Accordingly, the banding pitch x1 based on the meshing frequency of the development drive gear 52 is 0.5 [mm] or less so that the spatial frequency becomes 2.0 [lines / mm] or more, which is difficult to judge as human perceptual characteristics. Good.
Further, the banding pitch x1 based on the meshing frequency of the developing drive gear 52 is 2.0 [mm] or more so that the spatial frequency becomes 0.5 [lines / mm] or less, which is difficult to judge as human perceptual characteristics. Good. In the developing device 5, the banding pitch x1 can be changed by changing the number of rotations of the developing drive gear 52 and the number of teeth of the developing sleeve gear 54, for example, while the number of rotations of the developing sleeve 51 is kept constant. As a result, banding can be made inconspicuous on the image without reducing vibration.

In the developing device 5 according to the above-described embodiment, the developing drive gear 52, the idler gear 53, and the developing sleeve gear 54 are serial gear trains, and therefore all the gears have the meshing frequency f1. However, there are cases where the meshing frequency is different between the plurality of gears. In general, as shown in FIG. 4, when the drive input is gear drive by the development drive gear 52 which is the main body side drive transmission gear, the vibration having the meshing frequency f1 of the development drive gear 52 as a main component is generated on the photosensitive drum. It tends to be the largest among the vibrations propagating to 1. The reason for this is the meshing part of the gear held on the main body side and the gear held on the unit side, and it is difficult to fix the gear pitch, and vibration tends to occur in this part. Therefore, when driving is input by the developing drive gear 52 and the meshing frequencies are different among the plurality of gears, the meshing frequency of the developing drive gear 52 provided on the apparatus main body side may be used as a reference.
Further, the driving input to the developing device 5 may be by coupling coupling. In that case, the vibration whose main component is the meshing frequency of the developing sleeve gear 54, which is the final developing drive transmission gear provided coaxially with the developing sleeve 51, tends to be the largest among the vibrations propagated to the photosensitive drum 1. . The reason for this is the gear that drives the developing sleeve closest to the photosensitive member, and since it is in the vicinity of the drum, the influence of vibration propagation to the drum becomes stronger. Therefore, when it is not the drive input by the gear and the meshing frequency is different among the plurality of gears, the meshing frequency of the developing sleeve gear 54 may be used as a reference.

  The brush roller that rotates by bringing a brush into contact with a photosensitive member as an image carrier is not limited to the above-described photosensitive member cleaning brush roller. For example, even in the case of a brush roller to which a lubricant is applied, the brush contact frequency is set to be separated by ± 10 [%] or more with respect to the meshing frequency of the main body side development drive transmission gear or the final development drive transmission gear. This prevents moiré images from being generated by banding due to impact caused by the contact of the lubricant application brush roller with the photoreceptor and banding due to the meshing frequency of the main body side development drive transmission gear or the final development drive transmission gear. Can do.

As described above, according to the image forming apparatus according to the present embodiment, the meshing frequency f1 of the development driving gear 52 which is the main body side development driving gear and the brush contact where the bristles 61 of the photosensitive member cleaning brush roller 62 contact the photosensitive drum 1. The frequencies are separated such that the difference from the frequency f2 is 10% or more with respect to the smaller frequency value. Therefore, the meshing frequency f1 of the developing drive gear 52 becomes a vibration source, and the first banding pitch width that appears on the image and the brush contact frequency f2 of the photoconductor cleaning brush roller 62 appear on the image as the vibration source. The pitch width of the second banding is separated. Therefore, moire between the first banding and the second banding hardly occurs on the image, and a high-quality image can be obtained.
Further, the difference between the meshing frequency f1 of the developing sleeve gear 54 that is the final developing drive transmission gear and the brush contact frequency f2 at which the bristles 61 of the photosensitive member cleaning brush roller 62 contact the photosensitive drum 1 is the difference between the developing sleeve gear 54 and the developing sleeve gear 54. More than ± 10 [%] away from the meshing frequency f1. Therefore, the mesh band frequency f1 of the developing sleeve gear 54 becomes a vibration source and the first banding pitch width that appears on the image and the brush contact frequency f2 of the photoconductor cleaning brush roller 62 appear on the image as the vibration source. The pitch width of the second banding is separated. Therefore, moire between the first banding and the second banding hardly occurs on the image, and a high-quality image can be obtained.
Further, the photosensitive drum 1, the developing device 5, and the cleaning device 6 are integrally configured as a process cartridge 100. Therefore, the vibration caused by the meshing of the gear in the developing device 5 and the vibration caused by the meshing of the gear in the cleaning device 6 propagate to each other, and at the same time, the first banding and the second banding are likely to occur. However, since the pitch width of the first banding and the pitch width of the second banding are separated from each other, moire of banding hardly occurs and a high-quality image can be obtained.
Further, the banding pitch x1 based on the meshing frequency of the developing drive gear 52 is 0.5 [mm] or less. Therefore, it becomes difficult for human eyes to see the banding, and the banding can be made inconspicuous on the image without reducing the vibration.
In the image forming apparatus according to the present embodiment, the banding pitch x1 based on the meshing frequency of the developing drive gear 52 is 2.0 [mm] or more. Therefore, it becomes difficult for human eyes to see the banding, and the banding can be made inconspicuous on the image without reducing the vibration.

1 is a schematic configuration diagram illustrating an internal configuration of a printer according to an embodiment. FIG. 3 is a side configuration diagram illustrating an internal configuration of a process cartridge of the printer. FIG. 3 is a perspective configuration diagram showing an internal configuration of the process cartridge. The block diagram which shows the structure of the gear in the cleaning apparatus of the process cartridge. FIG. 4 is a schematic view of a photoconductor cleaning brush roller, (a) is a perspective view, and (b) is a cross-sectional view. The characteristic view which shows the relationship between a meshing frequency difference and the generation | occurrence | production degree of a moire. The characteristic view which shows the relationship between the visibility of a spatial frequency and banding.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 5 Developing device 6 Cleaning device 51 Developing sleeve 52 Developing drive gear 53 Idler gear 54 Developing sleeve gear 61 Hair 62 Photoconductor cleaning brush roller 63 Photoconductor cleaning driving joint 64 Driven joint 66 Pile winding boundary

Claims (5)

An image carrier;
A developing device comprising a developer carrier for developing a toner image on the image carrier and a plurality of development drive transmission gears for transmitting an input driving force to the developer carrier;
In an image forming apparatus having a brush roller that rotates in contact with the hair on the image carrier,
Of the development drive transmission gear, the meshing frequency of the development drive transmission gear on the main body side that transmits drive from the apparatus main body side to the development device, the number of hairs growing in the circumferential direction of the roller of the brush roller, and the brush roller The difference between the brush contact frequency determined by the product of the number of rotations of the brush and the brush frequency obtained by subtracting the smaller value from the larger frequency value is 10% or more of the smaller frequency value. An image forming apparatus. An image carrier;
A developing device comprising a developer carrier for developing a toner image on the image carrier and a plurality of development drive transmission gears for transmitting an input driving force to the developer carrier;
In an image forming apparatus having a brush roller that rotates in contact with the hair on the image carrier,
Of the development drive transmission gear, the engagement frequency of the final development drive transmission gear provided on the rotation shaft of the developer carrier and the number of hairs growing in the circumferential direction of the roller of the brush roller About the brush contact frequency obtained by multiplying the number of rotations, the difference obtained by subtracting the smaller value from the larger frequency value is 10% or more of the smaller frequency value. Image forming apparatus. The image forming apparatus according to claim 1 or 2,
The image forming apparatus according to claim 1, wherein the brush roller is an image carrier cleaning brush for cleaning residual toner on the image carrier. The image forming apparatus according to claim 1, 2 or 3.
An image forming apparatus according to claim 1, wherein a pitch on an image according to a meshing frequency of the main body side development drive gear or the final development drive transmission gear is smaller than 0.5 mm. The image forming apparatus according to claim 1, 2 or 3.
An image forming apparatus, wherein a pitch on an image according to a meshing frequency of the main body side development drive gear or the final development drive transmission gear is larger than 2.0 [mm].

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