JP2005017758A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can suppresses misalignment of the axes of a rotary engaging part in the driven side to rotate a developer carrying body and a rotary coupling part in the driving side installed in the image forming apparatus to apply the rotation driving force to the rotary engaging part, and which can prevent development irregularity. <P>SOLUTION: A rotary engaging part 52 disposed at least in one end of a developer carrying body 42 is engaged with a rotation coupling 62 in the image forming apparatus main body equipped a driving source so as to drive and rotate the developer carrying body by the driving source. Part of the developer carrying body 42 is engaged with the positioning part of the image forming apparatus so as to perform positioning of the developer carrying body in the image forming apparatus main body. The rotation engaging part and the rotation coupling member are installed in the developer carrying body 42 and in the image forming body, respectively, in such a manner that each rotation center is aligned to the rotation center of the developer carrying body 42 when the carrying body is positioned by engaging with the position engaging part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, and a printer. More specifically, the image forming apparatus includes a latent image carrier that carries a latent image on the surface and a developer carrier that carries an image forming substance on the surface. The present invention relates to an image forming apparatus including a developing device that visualizes a latent image and a transfer unit that transfers the visible image to a recording medium.
[0002]
[Prior art]
In an image forming apparatus such as a copying machine, a facsimile, or a printer, a rotating body such as a drum-shaped photoconductor or a developing roller is generally used. In order to transmit the rotational driving force to these rotating bodies, the rotating shaft on the rotating body side and the rotating shaft on the driving side are connected by a shaft coupling, and the rotational driving force is transmitted from the latter rotating shaft to the former rotating shaft. What is communicated is known.
[0003]
6 and 7 are cross-sectional views showing a drive connecting portion of a conventional developing device. The developing device 140 is composed of a developing roller 142 as a developer carrying member disposed so as to be partially exposed from the opening of the casing 141, a conveyance screw (not shown), a developing doctor, and the like. The developing roller shaft 150 extends from the inside of the casing 141 from the side surface of the casing 141 (right side in the drawing), and the roller gear 151 is fixed to the developing roller shaft 150 outside the casing 141. The roller gear 151 meshes with a coupling gear 152 that is rotatably supported on the side surface of the casing 141. Two claws 153 serving as protrusions are projected from the end face of the coupling gear 152. On the other hand, a drive output shaft 160 that is driven by a drive motor (not shown) is provided on the image forming apparatus main body side. The drive output shaft 160 as a driving shaft has a shaft 161 and a coupling 162 fixed to the end portion thereof. The coupling 162 has two claws 163 that individually correspond to the two claws 153 of the coupling gear 152 on the end surface thereof.
[0004]
When the developing device 140 is attached to a printer as an image forming apparatus, the coupling gear 152 on the developing device 140 side and the drive output shaft 160 on the printer main body side abut each other as shown in FIG. Then, the drive output shaft 160 and the coupling gear 152 are connected. A shaft coupling is configured by the end structure of the coupling gear 152 and the coupling 162 which is the end structure of the drive output shaft 160. By this shaft coupling, the rotational driving force of the drive output shaft 160 is connected to the coupling gear 152. Then, the rotational driving force is transmitted to the roller gear 151 meshed with the coupling gear 152, and the developing roller 142 rotates. In addition to this, a shaft coupling using an Oldham coupling is known as a coupling for coupling two rotating shafts (for example, Patent Document 1).
[Patent Document 1]
JP-A-6-332285
[0005]
[Problems to be solved by the invention]
However, the image forming apparatus as described above has the following problems.
As shown in FIG. 7, the developing device is positioned by inserting the developing roller shaft 150 into a holder 170 provided on the image forming apparatus main body side plate. Therefore, a coupling 162 that is a shaft end structure of the drive output shaft 160 that penetrates the same main body side plate as the holder 170 and an end structure of the coupling gear 152 that is meshed with the developing roller shaft 150 via the roller gear 151 are provided. A shaft misalignment may occur. Further, there has been a case where the axial misalignment occurs at the engaging portion due to the vibration of the developing device.
[0006]
The axial misalignment slightly changes the rotation speed of the developing roller 142 and causes uneven development density on the image for the following reason.
In the developing process, the toner in the two-component developer on the developing roller 142 is detached from the magnetic carrier and transferred onto the electrostatic latent image on the photoreceptor. At this time, it is preferable that the developing roller 142 rotates at a constant speed while the developing roller 142 maintains a constant gap with the photosensitive member. However, the rotational speed of the developing roller 142 slightly changes due to the axial misalignment, and the amount of toner per unit time conveyed to the developing position, which is the position where the photosensitive member and the developing roller face each other, changes. Will occur.
[0007]
In particular, when an image having a relatively large area ratio such as a photograph is printed out, the development density unevenness is conspicuous as compared with an image having a relatively small area ratio such as a text sentence. In a large monochrome image with a high area ratio, a certain development density unevenness occurs in a striped pattern in the sheet passing direction, and the aesthetic appearance is impaired. In a full color image with a large area ratio, uneven development density of each color appears as a hue shift. In the general market, such a large image is sometimes handled in, for example, a design occupation, and the commercial value is remarkably reduced by striped development density unevenness.
[0008]
In recent years, in addition to the demand for higher durability of devices, there is a growing demand for higher image quality. In order to achieve high image quality, the gap between the developing roller 42 and the photosensitive member tends to be narrowed. However, as the gap becomes narrower, development density unevenness due to fluctuations in rotational speed has become more prominent, and the axial misalignment cannot be ignored. In addition, with the recent reduction in diameter of devices, the coupling itself tends to be reduced in diameter. As the coupling diameter is reduced, the ratio of axial misalignment to the coupling diameter is increasing.
In some cases, the shaft misalignment may occur due to slight vibrations when the gear teeth come into contact, resulting in uneven development density. However, by changing the spur gear to a helical gear, a significant improvement was observed.
[0009]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a driven-side rotation engaging portion for rotating the developer carrying member and a rotational driving force to the rotation engaging portion. It is an object of the present invention to provide an image forming apparatus capable of preventing the uneven development density by suppressing the axial misalignment with the rotational coupling portion on the driving side provided on the main body side of the image forming apparatus to be sent.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 comprises a latent image carrier that carries a latent image on the surface and a developer carrier that carries an image forming substance on the surface, and the latent image is a visible image. In the image forming apparatus having the developing device that converts the image and the transfer unit that transfers the visible image onto the recording medium, a drive source is provided in the rotational engagement portion provided at least at one end of the developer carrier. The rotary coupling member on the image forming apparatus main body side is engaged, and the developer carrying body is rotationally driven by the driving source, and a part of the developer carrying body is positioned at the positioning portion on the image forming apparatus main body side. The developer carrying member is configured to be positioned within the image forming apparatus main body, and the rotation engagement portion and the rotation coupling member are engaged with the positioning portion. Rotation of the developer carrier when positioned together To match the heart, it is characterized in that provided in each developing bearing member and an image forming main body.
According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the positioning portion is formed on the rotary coupling member, and a part of the developer carrying member is engaged with the positioning portion, so that the positioning is performed. It is characterized by having comprised so that.
According to a third aspect of the present invention, in the image forming apparatus of the second aspect, a part of the developer carrying member is a rotating shaft of the developer carrying member, and the positioning portion is formed by the coupling member. It is a center hole into which the tip of the rotating shaft enters.
According to a fourth aspect of the present invention, in the image forming apparatus according to the first, second, or third aspect, the rotary coupling member is made of a conductive material, and the developer carrier is provided through the rotary coupling member. A developing bias is supplied.
According to a fifth aspect of the present invention, in the image forming apparatus according to the first, second, third, or fourth aspect, a groove is formed on the surface of the developer carrying member.
According to a sixth aspect of the present invention, in the image forming apparatus according to the first, second, third, fourth, or fifth aspect, a development gap that is a distance between the surface of the latent image carrier and the surface of the developer carrier is 0.00. 4 [mm] or less.
The invention according to claim 7 is the image forming apparatus according to claim 1, wherein the image forming substance is a two-component developer comprising toner and magnetic particles. An oilless polymer toner or a low-melting toner is used as the magnetic particles, and the magnetic core material is coated with a resin coat film. The resin coat film crosslinks the thermoplastic resin and the melanin resin. And a resin component containing a charge control agent.
[0011]
According to the first to seventh aspects of the present invention, the rotation engagement portion and the rotation coupling member are positioned when their respective rotation centers are engaged with the positioning portions on the image forming apparatus main body side of the developer carrier. This coincides with the rotation center of the developer carrying member. Therefore, the rotation centers of the rotation engagement portion and the rotation coupling member are arranged on a straight line, and axial misalignment can be prevented. Then, the fluctuation of the toner amount per unit time conveyed to the developing position, which is the position where the latent image carrier and the developer carrier are opposed to each other, while suppressing the fluctuation in the rotation speed of the developer carrier caused by the axial misalignment. And development density unevenness can be prevented.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is applied to an electrophotographic tandem color laser printer (hereinafter simply referred to as a printer) as an image forming apparatus will be described.
[Overall Configuration] FIG. 1 is a schematic configuration diagram of a laser printer according to the first embodiment. This laser printer includes four sets of process units 1Y, M, C, and K for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K). Needless to say, Y, M, C, and K appended to the numerals of the respective symbols indicate members for yellow, magenta, cyan, and black (the same applies hereinafter). In addition to the process units 1Y, 1M, 1C, and 1K, an optical writing unit 10, a transfer unit 11, a registration roller pair 19, three paper feed cassettes 20, a fixing unit 21, and the like are disposed.
[0013]
[Optical Writing Unit] The optical writing unit 10 includes four optical writers. Each optical writer includes a light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates a laser beam on the surface of a photoconductor described later based on image data.
[0014]
[Process Unit] FIG. 2 is an enlarged view showing a schematic configuration of the process unit 1Y for yellow among the process units 1Y, 1M, 1C, and 1K. Since the other process units 1M, 1C, and 1K have the same configuration, their descriptions are omitted. In FIG. 2, the process unit 1Y includes a drum-shaped photoreceptor 2Y, a charger 30Y, a developing device 40Y, a drum cleaning device 48Y, and the like.
[0015]
The charger 30Y uniformly charges the drum surface by sliding a charging roller to which an AC voltage is applied against the photoreceptor 2Y. The surface of the photoreceptor 2Y subjected to the charging process is irradiated with the laser beam modulated and deflected by the optical writing unit 10 while being scanned. Then, an electrostatic latent image is formed on the drum surface. The formed electrostatic latent image is developed by the developing device 40Y to become a Y toner image.
[0016]
The developing device 40Y has a developing roller 42Y disposed so as to be partially exposed from the opening of the casing. Further, it also includes a first transport screw 43Y, a second transport screw 44Y, a developing doctor 45Y, a toner concentration sensor (hereinafter referred to as T sensor) 46Y, and the like.
[0017]
A two-component developer containing a magnetic carrier and negatively chargeable Y toner is accommodated in the casing. The two-component developer is frictionally charged while being agitated and conveyed by the first conveying screw 43Y and the second conveying screw 44Y, and then carried on the surface of the developing roller 42Y. Then, after the layer thickness is regulated by the developing doctor 45Y, the layer is conveyed to a developing region facing the photoreceptor 2Y, where Y toner is attached to the electrostatic latent image on the photoreceptor 2Y. This adhesion forms a Y toner image on the photoreceptor 2Y. The two-component developer that has consumed Y toner by development is returned to the casing as the developing roller 42Y rotates.
[0018]
A partition wall 47Y is provided between the first transport screw 43Y and the second transport screw 44Y. The partition wall 47Y separates the first supply unit that accommodates the developing roller 42Y, the first conveyance screw 43Y, and the like and the second supply unit that accommodates the second conveyance screw 44Y in the casing. The first conveying screw 43Y is rotationally driven by a driving unit (not shown), and supplies the two-component developer in the first supply unit to the developing roller 42Y while conveying the two-component developer from the front side to the back side in the drawing. The two-component developer conveyed to the vicinity of the end of the first supply unit by the first conveyance screw 43Y enters the second supply unit through an opening (not shown) provided in the partition wall 47Y. In the second supply section, the second transport screw 44Y is driven to rotate by a driving means (not shown), and transports the two-component developer sent from the first supply section in the direction opposite to that of the first transport screw 43Y. . The two-component developer transported to the vicinity of the end of the second supply unit by the second transport screw 44Y returns to the first supply unit through the other opening (not shown) provided in the partition wall 47Y. .
[0019]
The T sensor 46Y including a magnetic permeability sensor is provided on the bottom wall near the center of the second supply unit, and outputs a voltage having a value corresponding to the magnetic permeability of the two-component developer passing therethrough. Since the magnetic permeability of the two-component developer has a certain degree of correlation with the toner density, the T sensor 66Y outputs a voltage having a value corresponding to the Y toner density. This output voltage value is sent to a control unit (not shown). This control unit includes a RAM, in which Y Vtref, which is a target value of the output voltage from the T sensor 46Y, is stored. In addition, data of M Vtref, C Vtref, and K Vtref, which are target values of output voltage from a T sensor (not shown) mounted in another developing device, is also stored. The Y Vtref is used for driving control of a Y toner conveying device (not shown). Specifically, the control unit drives and controls a Y toner conveying device (not shown) so that the value of the output voltage from the T sensor 46Y approaches the V Vref for Y to replenish Y toner in the second supply unit 49Y. Let By this replenishment, the Y toner concentration of the two-component developer in the developing device 40Y is maintained within a predetermined range. Similar toner replenishment control is performed for the developing devices of other process units.
[0020]
The Y toner image formed on the Y photoconductor 2Y is transferred onto a transfer sheet that is transported to a paper transport belt described later. The surface of the photoreceptor 2Y after the transfer is neutralized by a static eliminator (not shown) after the transfer residual toner is cleaned by the drum cleaning device 48Y. Then, it is uniformly charged by the charger 30Y and prepared for the next image formation. The same applies to other process units. Each process unit is attachable to and detachable from the printer body, and is replaced when the service life is reached.
[0021]
[Transfer Unit] In FIG. 1 described above, the transfer unit 11 includes a paper transport belt 12, a drive roller 13, a stretching roller 14, four transfer bias rollers 17Y, M, C, and K. . The paper conveying belt 12 is endlessly moved counterclockwise in the figure by a driving roller 13 that is rotated by a driving system (not shown) while being tensioned by the driving roller 13 and the stretching rollers 14 and 15. A transfer bias is applied to each of the four transfer bias rollers 17Y, 17M, 17C, and 17K from a power source (not shown). Then, the paper conveying belt 12 is pressed from the back surface thereof toward the photoreceptors 2Y, 2M, 2C, and 2K to form transfer nips. At each transfer nip, a transfer electric field is formed between the photoconductor and the transfer bias roller due to the influence of the transfer bias. The above-mentioned Y toner image formed on the Y photoconductor 2Y is transferred onto the transfer paper P that is transported onto the paper transport belt 12 due to the influence of the transfer electric field and nip pressure. On the Y toner image, the M, C, and K toner images formed on the photoreceptors 2M, 2C, and 2K are sequentially superimposed and transferred. By such superposition transfer, a full-color toner image combined with the white color of the paper is formed on the transfer paper P transported on the paper transport belt 12.
[0022]
[Paper Feed Cassettes] Below the transfer unit 11, three paper feed cassettes 20 for accommodating a plurality of transfer papers P in a stacked manner are arranged in multiple stages, and each cassette is the top transfer paper. A paper feed roller is pressed against P. When the paper feed roller is driven to rotate at a predetermined timing, the uppermost transfer paper P is fed to the paper transport path.
[0023]
[Registration Roller Pair] The transfer paper P fed from the paper feed cassette 20 to the paper conveyance path is sandwiched between the rollers of the registration roller pair 19. The registration roller pair 19 sends out the transfer paper P sandwiched between the rollers at a timing at which toner images can be superimposed at each transfer nip. As a result, the toner image is superimposed and transferred onto the transfer paper P at each transfer nip. The transfer paper P on which the full color image is formed is sent to the fixing unit 21.
[0024]
[Fixing Unit] The fixing unit 21 forms a fixing nip by a heating roller 21a having a heat source such as a halogen lamp inside and a pressure roller 21b pressed against the heating roller 21a. The full color image is fixed on the surface of the transfer paper P while being sandwiched in the fixing nip. The transfer paper P that has passed through the fixing unit 21 is discharged out of the apparatus through a pair of paper discharge rollers (not shown).
[0025]
Next, a characteristic configuration of the laser printer will be described.
3 and 4 are cross-sectional views showing the drive connecting portion of the developing device according to this embodiment. From the casing side surface of the developing device 40, a developing roller shaft 50Y extends from the inside of the casing. Outside the casing, as shown in the figure, a coupling gear 52Y as a rotation engaging portion, in which the developing roller shaft 50Y is supported on the side surface of the casing, is integrally formed. Two claws 53Y as projecting portions are projected from the end face of the coupling gear 52Y. On the other hand, a drive shaft 65Y that receives driving from a drive motor (not shown) is provided on the printer body side. The drive shaft 65Y as the driving shaft has an axis 66Y and a drive gear 67Y fixed to the end portion thereof. The drive gear 67Y is configured to mesh with the idler gear 68Y, and the idler gear 68Y is configured to mesh with the drive output gear 69Y. The drive output shaft 60Y is fixed to the drive output gear 69Y, and the drive output shaft 60Y is rotated from the drive motor via the drive gear 67Y, the idler gear 68Y, and the drive output gear 69Y. The drive output shaft 60Y has a shaft core 61Y and a coupling member 62Y fixed to the end portion thereof. This coupling 62Y has two claws 63Y on the end face thereof, which individually face the two claws 53Y of the coupling gear. Further, the coupling 62Y is provided with a recess 64 for inserting and engaging the shaft end portion 54 of the developing roller shaft 50Y with the coupling 62Y.
[0026]
When the developing device for Y is mounted on the printer main body, the coupling gear 52Y on the developing device 40Y side and the coupling member 62Y on the drive output shaft 60Y on the printer main body side are abutted and connected. A shaft coupling is constituted by the end structure of the coupling gear 52 and the coupling 62Y which is the shaft end structure of the drive output shaft 60Y. The developing roller 42Y rotates by this shaft coupling. At the same time, the shaft end of the developing roller shaft 50Y is inserted into and engaged with the recess 64 provided in the coupling 62Y. As a result, the developing roller 42 is positioned with respect to the printer body side plate 70. The photosensitive member 2 is configured to be positioned with respect to the printer main body side plate 70 by the same method as described above or by a known method. Therefore, the developing roller 42 and the photosensitive member surface are made to face each other with a predetermined gap.
[0027]
The drive output shaft 60Y as a driving shaft is made of a conductive material, and supplies a developing bias from the printer main body via an electrode. Since the developing bias is supplied from the drive output shaft 60Y rotating integrally with the developing roller 42, it is possible to prevent conduction failure (contact failure).
[0028]
In each process unit, it is desirable that the gap between the photosensitive member 2 and the developing roller 42 be 0.4 [mm] or less. Then, compared with the case where the gap is made wider than this, the granularity of the developed toner image can be greatly improved, and a high-quality image can be obtained. Narrowing the gap in this way tends to cause uneven development density due to fluctuations in the rotation speed of the developing roller, but this laser printer suppresses fluctuations in the rotation speed, so image quality deterioration due to the occurrence of uneven development density is effective. It is suppressed to.
[0029]
Further, it is desirable to stabilize the pumping amount of the two-component developer by the roller by carving a groove such as a V-groove on the surface of the developing roller 42 or roughening it by sandblasting. By doing so, not only development density unevenness due to fluctuations in the rotational speed of the roller, but also development density unevenness due to fluctuations in the pumping amount can be suppressed. In general, a developing roller that has been subjected to groove processing such as a V-groove is more preferable than a developing roller that has been sandblasted because it can be stably conveyed with no wear even when used for a long period of time.
[0030]
Further, as a carrier as a magnetic particle, a resin-coated film is formed on a magnetic core material, and the resin-coated film is a resin component obtained by crosslinking a thermoplastic resin such as acrylic and a melanin resin. It is desirable to use one containing a regulator. The conventional carrier is configured to obtain a long life while gradually scraping a hard coat film, whereas this carrier absorbs an impact and suppresses the film scraping because the coat film has elasticity. Therefore, the lifetime can be further extended as compared with the conventional carrier. Accordingly, it is possible to expect stabilization of the toner pumping amount, that is, stabilization of quality over a long period of time. In this embodiment, a carrier having a small particle diameter of 20 [μm] or more and 60 [μm] or less is used as the carrier. The magnetic carrier has a small particle diameter of 60 [μm] or less, and it is possible to prevent grain marks and halftone images from being roughened by the magnetic carrier, that is, deterioration of graininess, improving dot reproducibility and improving image quality. Is possible. Further, the magnetic carrier is made to have a particle size of 20 [μm] or more so that the fluidity and stress on the developer are not deteriorated too much.
[0031]
As for the toner, it is desirable to use an oil-containing toner containing an oil component. This is due to the following reason. That is, in the fixing method using the oilless polymerized toner, a glossy image cannot be obtained. Therefore, it is necessary to apply oil to the fixing roller in order to achieve glossiness. If it does so, it will become easy to generate | occur | produce uneven glossiness in an image by the oil application unevenness to a fixing roller. On the other hand, if an oil-containing toner is used, gloss can be naturally produced by oil oozing from the toner particles during fixing, so that uneven gloss due to uneven oil application can be avoided. Examples of the oil-containing toner include the following. That is, first, a prepolymer made of a resin, a compound that extends or crosslinks with the prepolymer, and a toner composition are dissolved or dispersed in an organic solvent. The toner is obtained by inducing a crosslinking reaction or an elongation reaction in the medium and removing the solvent from the dispersion.
Further, it is desirable to use a low-melting toner having a melting point of 140 degrees or less. This is because fixing can be performed at a temperature lower than that of conventional toner, so that the fixing unit can be started up early and an energy saving effect can be expected.
[0032]
[Modification 1]
Next, a modified example of the developing roller positioning structure with respect to the printer main body will be described.
FIG. 5 is a cross-sectional view showing a drive connecting portion of a developing device according to a modification. The basic configuration and operation of this drive connecting portion are the same as those of the above-described embodiment, except for the following points. That is, in the above embodiment, the developing roller is positioned with respect to the printer body by inserting the shaft end portion of the developing roller shaft 50 of the developing roller into the concave portion 64 provided in the coupling 62. In this modification, the cylindrical portion 75 protruding outward from the end surface of the developing roller is inserted into the outer peripheral surface of the coupling body, whereby the developing roller is positioned with respect to the printer body. Here, the center of the cylindrical portion 75 is configured to coincide with the center of the developing roller. As shown in FIG. 5, the developing roller 42 is supported by a flange portion fixed to the casing side plate via a bearing 73 (ball bearing, sliding bearing, etc.).
[0033]
The printer used in the above embodiment is an example of an apparatus to which the present invention can be applied, and is not limited to this apparatus. Although an example in which a two-component developer is applied has been described for the developer, it is naturally applicable to a one-component developer.
[0034]
【The invention's effect】
According to the first to seventh aspects of the present invention, a driven-side rotation engaging portion for rotating the developer carrying member and a driving force provided on the image forming apparatus main body side that sends a rotational driving force to the rotation engaging portion. There is an excellent effect that development density unevenness due to axial misalignment with the rotary coupling portion on the side can be prevented.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a laser printer according to an embodiment.
FIG. 2 is an enlarged configuration diagram showing a process unit for Y of the laser printer.
FIG. 3 is a cross-sectional view showing a drive connecting portion of the developing device according to the present embodiment.
FIG. 4 is a cross-sectional view showing a drive connecting portion of the developing device according to the present embodiment.
FIG. 5 is a cross-sectional view showing a drive connecting portion of a developing device according to a modification.
FIG. 6 is a cross-sectional view showing a drive connecting portion of a conventional developing device.
FIG. 7 is a cross-sectional view showing a drive connecting portion of a conventional developing device.
[Explanation of symbols]
1Y, M, C, K Process unit
2 Photoconductor
11 Transfer unit
40 Developer
41 Casing
42 Development roller
50 Developing roller shaft
52 Coupling gear
60 Drive output shaft
61 shaft core
62 coupling

Claims (7)

A latent image carrier that carries a latent image on the surface, a developer carrier that carries an image forming substance on the surface, a developing device that visualizes the latent image, and the visible image transferred to a recording medium An image forming apparatus having transfer means for
A rotary coupling member on the image forming apparatus main body side provided with a drive source is engaged with a rotation engagement portion provided at least at one end of the developer carrier, and the developer carrier is rotated by the drive source. Configured to drive,
A part of the developer carrier is engaged with a positioning portion on the image forming apparatus main body side, and the developer carrier is configured to be positioned in the image forming apparatus main body.
The rotation engagement portion and the rotation coupling member are arranged on the developer carrier side so that the respective rotation centers coincide with the rotation center of the developer carrier when the rotation engagement portion and the rotation coupling member are positioned by being engaged with the positioning portion. And an image forming apparatus provided on each side of the image forming main body. The image forming apparatus according to claim 1.
An image forming apparatus, wherein the positioning portion is formed on the rotary coupling member, and the positioning is performed by engaging a part of the developer carrier with the positioning portion. The image forming apparatus according to claim 2.
A part of the developer carrying member is a rotating shaft of the developer carrying member, and the positioning portion is a central hole into which a tip of the rotating shaft formed by the coupling member enters. apparatus. The image forming apparatus according to claim 1, 2, or 3.
2. The image forming apparatus according to claim 1, wherein the rotary coupling member is made of a conductive material, and a developing bias is supplied to the developer carrier through the rotary coupling member. The image forming apparatus according to claim 1, 2, 3, or 4.
An image forming apparatus having a groove on the surface of the developer carrying member. The image forming apparatus according to claim 1, 2, 3, 4, or 5.
An image forming apparatus, wherein a development gap, which is a distance between the surface of the latent image carrier and the surface of the developer carrier, is 0.4 [mm] or less. The image forming apparatus according to claim 1, 2, 3, 4, 5, or 6.
The image forming substance is a two-component developer composed of toner and magnetic particles, and an oilless polymer toner or a low melting point toner is used as the toner, and the magnetic core material is coated with a resin coating film as the magnetic particles. An image forming apparatus, wherein the resin coat film includes a resin component obtained by crosslinking a thermoplastic resin and a melanin resin, and a charge adjusting agent.

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