JP2017058520A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology to provide lubricity between a cleaning member, such as a cleaning blade and image carriers, such as photoconductor drums.SOLUTION: A control part 10 supplies, on the basis of the degree of deterioration of a developer, a supplement developer to an image carrier 1 in an image forming unit C, of a plurality of image forming units C, storing a developer with the smallest degree of deterioration; subsequently moves the supplement developer to an image carrier 1 in an image forming unit C, of the plurality of image forming unit C, storing a developer with the largest degree of deterioration; and executes a supply operation of causing a cleaning member 6a in the image forming unit C storing a developer with the largest degree of deterioration to remove the supplement developer.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an image forming apparatus using electrophotographic technology.

  In an image forming apparatus using electrophotographic technology, an image is formed on a sheet by transferring a toner image formed on a photosensitive drum onto the sheet. Here, the toner (residual developer) may remain on the photosensitive drum after the toner image on the photosensitive drum is transferred to the sheet. Therefore, the image forming apparatus is provided with a cleaning blade for removing residual toner on the photosensitive drum. However, an increase in the coefficient of friction of the surface of the photosensitive drum may cause the cleaning blade to turn over, or abnormal noise may occur due to rubbing between the cleaning blade and the photosensitive drum.

  Therefore, a technique for supplying toner having lubricity to a portion where the cleaning blade and the photosensitive drum are in contact with each other is known. In the technique disclosed in Patent Document 1, in a color image forming apparatus having four process cartridges, the image forming apparatus supplies toner of a color with good lubricity to a cleaning blade provided in the process cartridge. . Specifically, the image forming apparatus supplies toner having a color with good lubricity to a cleaning blade provided in another process cartridge from a process cartridge in which toner with a color having good lubricity is stored. Yes. In the technique disclosed in Patent Document 2, the image forming apparatus supplies toner from a process cartridge having a large amount of stored toner to a cleaning blade provided in the process cartridge having a small amount of stored toner. ing.

  Here, when the toner deteriorates, the lubricity of the toner decreases. The toner is formed by adding external additives which are inorganic fine particles such as a lubricant and a charge control agent to resin particles containing a charge control agent and a pigment. However, the external additive may be embedded in the resin particles when the developing blade and the toner rub against each other. This phenomenon is expressed as toner deterioration. As the toner deteriorates, the lubricity of the toner decreases. When the lubricity of the toner is lowered, even if the toner is supplied between the cleaning blade and the photosensitive drum, the friction generated between the cleaning blade and the photosensitive drum may not be sufficiently suppressed.

Japanese Patent Laid-Open No. 11-194690 JP 2011-150304 A

  Therefore, an object of the present invention is to provide lubricity between a cleaning member such as a cleaning blade and an image carrier such as a photosensitive drum.

In order to achieve the above object, an image forming apparatus according to the present invention comprises:
An image carrier for carrying an electrostatic image;
A developing device for developing the electrostatic image as a developer image;
A plurality of image forming units having a cleaning member that removes residual developer remaining on the image carrier after the developer image is transferred to the transfer body by contacting the image carrier;
A storage device for storing the deterioration degree of the developer based on the usage amount of the developing device;
A control unit that performs a supply operation of supplying a developer to the cleaning member,
The control unit supplies the supplied developer to an image carrier of an image forming unit having a small degree of deterioration of the stored developer among the plurality of image forming units based on the degree of deterioration of the developer, and then The supplied developer is moved to an image carrier of an image forming unit having a large degree of deterioration of the stored developer among the image forming units, and the supply and development is performed on a cleaning member in the image forming unit having a large degree of deterioration of the developer. A supply operation for removing the agent is performed.

In order to achieve the above object, an image forming apparatus according to the present invention includes:
A first image carrier for carrying a first electrostatic image;
A second image carrier for carrying a second electrostatic image;
A first developing device for developing the first electrostatic image as a developer image;
A second developing device for developing the second electrostatic image as a developer image;
A first cleaning member that contacts the first image carrier to remove residual toner remaining on the first image carrier after the developer image is transferred to the transfer member;
A second cleaning member that removes residual toner remaining on the second image carrier after the developer image is transferred to the transfer body by contacting the second image carrier;
Based on the first deterioration level of the developer based on the usage amount of the first developing device and the second deterioration level of the developer based on the usage amount of the second developing device, the developer is applied to the second cleaning member. A control unit that performs a supply operation to supply,
The control unit supplies the supplied developer from the first developing device to the first image carrier when the second degradation degree is greater than the first degradation degree, and then the second image carrier. The supply developer is moved, and a supply operation for supplying the supply developer to the second cleaning member is executed.

  According to the present invention, lubricity can be imparted between a cleaning member such as a cleaning blade and an image carrier such as a photosensitive drum.

1 is a schematic sectional view of an image forming apparatus according to a first embodiment. The figure which shows the operation | movement which supplies a toner to another image forming unit The figure which shows the operation | movement with which toner is supplied from another image forming unit. 6 is a flowchart illustrating a flow of toner supply operation according to the first exemplary embodiment. FIG. 10 is a diagram illustrating a method of classifying the degree of toner deterioration according to the second embodiment. 7 is a flowchart illustrating a flow of a toner supply operation according to the second embodiment.

  Embodiments of the present invention will be illustrated below with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the embodiments should be appropriately changed depending on the configuration of the apparatus to which the invention is applied and various conditions. This is not intended to limit the scope to the following embodiments.

Example 1
An image forming operation of the image forming apparatus S according to the first embodiment will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view of the image forming apparatus according to the first embodiment. The image forming apparatus S includes an apparatus main body of the image forming apparatus S and process cartridges Cy, Cm, Cc, and Ck. That is, the image forming apparatus S has a plurality of process cartridges C. The process cartridge Cy forms a toner image as a yellow developer image. The process cartridge Cm forms a magenta toner image. The process cartridge Cc forms a cyan toner image. The process cartridge Ck forms a black toner image.

A station that forms a toner image and has a process cartridge Cy (image forming unit Cy) mounted thereon is defined as a first station. A station to which the process cartridge Cm is mounted is a second station. A station to which the process cartridge Cc is mounted is set as a third station. A station to which the process cartridge Ck is mounted is assumed to be a fourth station. Here, the process cartridges Cy to Ck have the same configuration except for the color of the stored toner. Therefore, in the process cartridges Cy to Ck, the same parts are collectively described with the suffixes y to k being omitted unless otherwise limited. However, the process cartridge is not limited to the same size and the like. For example, the size of the black process cartridge may be larger than other process cartridges.
In this embodiment, the process cartridge that is an image forming unit is detachable from the apparatus main body of the image forming apparatus. However, the present invention is not limited to this, and a photosensitive drum that is an image carrier is fixed to the image forming apparatus. The portion may be detachable.

  An image forming process will be described using the process cartridge Cy in the first station. The process cartridge Cy includes a photosensitive drum 1y, a charging roller 2y, a developing device 4y, and a cleaning device 6y. The photosensitive drum 1y rotates in the direction of arrow R1 in FIG. The photosensitive drum 1y is uniformly charged to a predetermined potential by a charging roller 2y that rotates while being in contact with the photosensitive drum 1y. The photosensitive drum 1y is exposed by the laser beam Ly transmitted from the exposure device 3, whereby an electrostatic latent image as an electrostatic image is formed on the surface of the photosensitive drum 1y. The developing device 4y includes a negatively charged nonmagnetic one-component toner as a developer. The developing device 4y includes a rotatable developing roller 4ay and a developing blade 4by that is in contact with the developing roller 4ay in order to impart charge to the toner. The developer of the present embodiment is a non-magnetic one-component toner, but is not limited to this, and may be magnetic or two-component depending on the configuration.

  Here, the negatively chargeable non-magnetic one-component toner housed in the developing device 4y is composed of a base made of resin particles and an external additive made of inorganic fine particles such as silica. The developing roller 4ay contacts the photosensitive drum 1y at a desired timing to supply toner to the surface of the photosensitive drum 1y. As a result, the electrostatic latent image on the photosensitive drum 1y becomes obvious, and a toner image is formed on the photosensitive drum 1y.

  The toner image on the photosensitive drum 1y is primarily transferred to the intermediate transfer member 7 by a first transfer roller 5y as a primary transfer member. The toner image on the intermediate transfer member 7 is conveyed in the direction of arrow R2. Residual toner remaining on the photosensitive drum 1y without being transferred to the intermediate transfer member 7 is removed by a cleaning blade 6ay as a cleaning member in contact with the photosensitive drum 1y. The cleaning blade 6ay is fixed to a cleaning device 6y that collects residual toner. Further, the urethane rubber portion in the cleaning blade 6ay is in contact with the rotation direction of the photosensitive drum 1y in the counter direction.

Similarly, toner images are formed in the process cartridges Cm to Ck. The toner images formed by the process cartridges Cy to Ck are sequentially superimposed and transferred onto the intermediate transfer body 7. The toner image transferred onto the intermediate transfer member 7 is transferred onto the recording material P by a second transfer roller 8 as a secondary transfer member. Then, the recording material P as a recording medium to which the toner image is transferred is heated and fixed by the fixing roller 9. As a result, the toner image is fixed on the recording material P.
In this embodiment, the first transfer roller that is the primary transfer member is used, but the present invention is not limited to this, and the second transfer roller is used so that the developer image can be primarily transferred to the intermediate transfer belt that is the intermediate transfer member. Alternatively, a potential may be applied to the intermediate transfer belt. In this case, the first transfer roller is unnecessary.

  In addition, a storage device 6by that stores the use history of the process cartridge C is provided in the cleaning device 6y. The control unit 10 provided in the apparatus main body of the image forming apparatus writes information in the storage device 6by and refers to the information stored in the storage device 6by. The photosensitive drum 1 (1y to 1k) rotates at 100 mm / sec. Further, the surface speed (peripheral speed) of the developing roller 4 a is 1.4 times (140%) the peripheral speed of the photosensitive drum 1. The surface of the developing roller 4 a rotates in the same direction as the surface of the photosensitive drum 1.

<Operation of supplying toner at the time of non-image formation in one station>
An operation for supplying toner to the cleaning blade 6a in one station will be described. Supplying toner to the cleaning blade 6a is referred to as toner supply operation. By executing the toner supply operation during a period when the above-described image forming operation is not performed (during non-image formation), the frictional force between the cleaning blade 6a and the photosensitive drum 1 can be reduced. In this case, the timing for executing the toner supply operation is determined by the moving distance a of the surface of the photosensitive drum 1 in the circumferential direction of the photosensitive drum 1. Here, the movement distance “a” of the surface of the photosensitive drum 1 is specifically the distance that a specific position on the outer peripheral surface of the photosensitive drum 1 has moved in the circumferential direction of the photosensitive drum 1. The moving distance of the surface of the photosensitive drum 1 is also expressed as a traveling distance. The toner supply operation during non-image formation is executed within a predetermined period after the image formation operation is completed. After the image forming operation is completed, the photosensitive drum 1 is rotated by continuously driving the main motor for a predetermined period (post-rotation operation). During this period, the toner supply operation is executed.

  In this toner supply operation, as in the image forming operation, a solid black toner image (supply developer) is formed on the photosensitive drum 1 (on the image carrier). Then, the toner image is supplied to the cleaning blade 6a in the process cartridge C on which the solid black toner image is formed. In this toner supply operation, the toner image on the photosensitive drum 1 must not be transferred onto the intermediate transfer member 7. For this reason, it is necessary to apply a voltage having a polarity opposite to that applied to the first transfer roller 5 (5y to 5k) to the first transfer roller 5 during image formation. As a result, a solid black toner image is supplied to the cleaning blade 6a.

<Operation for supplying toner to other stations during non-image formation>
In this operation, the toner image formed at a predetermined station is supplied to the cleaning blade 6a at another station. This operation will be described with reference to FIGS. FIG. 2 is a diagram illustrating an operation of supplying toner to another station. FIG. 3 is a diagram illustrating an operation in which toner is supplied from another station.

  This toner supply operation will be described by taking as an example an operation of supplying toner from the second station to the third station. This is a case where the deterioration level (first deterioration level) of the toner stored in the second station is higher than the deterioration level (second deterioration level) of the toner stored in the third station. As described above, the process cartridge Cm is arranged at the second station. A process cartridge Cc is disposed at the third station. The photosensitive drum 1m as the first image carrier and the photosensitive drum 1c as the second image carrier rotate in the direction R3 in FIG. Further, the process cartridge Cm is provided with a cleaning blade 6am as a first cleaning member. The intermediate transfer member 7 has moved in the direction of arrow R4.

The operation of supplying toner from the second station will be described with reference to FIGS. 2 (A) and 2 (B). FIG. 2A is a diagram illustrating a state in which toner is supplied from the second station to the third station. FIG. 2B is a diagram showing the timing for switching on / off the operation of the charging roller 2m, the exposure device 3, the developing device 4m as the first developing device, and the first transfer roller 5m. As shown in FIG. 2B, a voltage starts to be applied to the charging roller 2m at timing T1.

  Next, at timing T2, the photosensitive drum 1m starts to be exposed by the exposure device 3. Thereby, an electrostatic latent image is formed on the photosensitive drum 1m. Further, a voltage is applied to the developing roller 4am at timing T2. When the developing roller 4am comes into contact with the photosensitive drum, a solid black toner image T is formed on the photosensitive drum 1m. The charging of the photosensitive drum 1m, the exposure to the photosensitive drum 1m, and the development of the electrostatic latent image are performed in the same manner as a normal image forming operation. Further, in order to transfer the toner image T on the photosensitive drum 1m onto the intermediate transfer member 7, a positive voltage is applied to the transfer roller 5m at timing T2.

  Then, exposure by the exposure device 3 ends at timing T3 so that a desired toner image T is formed. Further, at the timing T3, the voltage applied to the charging roller 2m is turned off. Further, at timing T4, at timing T4 when the toner image T is completely formed on the photosensitive drum 1m, the developing roller 4am is separated from the photosensitive drum 1m, and the voltage applied to the developing roller 4am is turned off. Finally, at the timing T5 when the toner image T on the photosensitive drum 1m is transferred onto the intermediate transfer member 7, the voltage applied to the transfer roller 5m is turned off.

  The toner image T formed at the second station is transferred to the intermediate transfer member 7 and then conveyed to the third station by the intermediate transfer member 7. Next, the operation of supplying toner to the third station will be described with reference to FIGS. 3 (A) and 3 (B). Here, FIG. 3A is a diagram illustrating a state in which toner is supplied from the second station to the third station. FIG. 3B is a diagram showing the timing for switching on / off the operations of the charging roller 2m, the exposure device 3, the developing device 4m, and the first transfer roller 5m.

  As shown in FIG. 3B, a voltage starts to be applied to the charging roller 2c at timing T11. Next, at timing T12, the photosensitive drum 1c starts to be exposed by the exposure device 3. The charging of the photosensitive drum 1m, the exposure to the photosensitive drum 1m, and the development of the electrostatic latent image are performed in the same manner as a normal image forming operation. At timing T12, a voltage (minus) having a polarity opposite to that at the time of image formation is applied to the first transfer roller 5c so that the toner image T on the intermediate transfer body 7 is transferred to the photosensitive drum 1c. As a result, an electric field is generated between the first transfer roller 5c and the photosensitive drum 1c in the direction opposite to that during the normal image forming operation.

  At time T13 when the toner image on the intermediate transfer body 7 is transferred to the photosensitive drum 1c, the voltage applied to the charging roller 2c is turned off. At timing T13, the exposure of the photosensitive drum 1c by the exposure device 3 is completed. At timing T14, the voltage applied to the transfer roller 5c is turned off. As described above, the toner stored in the second station is conveyed by the intermediate transfer member 7 and supplied to the cleaning blade 6ac as the second cleaning member via the photosensitive drum 1c. Thereby, the frictional force between the photosensitive drum 1c and the cleaning blade 6ac is reduced.

<Development device usage>
In this embodiment, the degree of deterioration of the toner is obtained based on the usage amount of the developing device 4 (4y to 4k). Further, the usage amount of the developing device 4 is determined by the number of rotations of the developing roller 4a. In this embodiment, the usage amount of the developing device is the usage amount of the developing roller which is a developer carrier. The toner external additives are the developing roller 4a (4ay to 4ak) and the developing blade 4b (4by to 4bk).
) May be embedded in the toner resin particles. Therefore, the degree of toner deterioration can be estimated from the number of rotations of the developing roller 4a. The developing roller 4a rotates when driving is transmitted from the apparatus main body of the image forming apparatus S. Since the rotation speed of the developing roller 4a is constant, the number of rotations of the developing roller 4a can be detected by detecting the driving time of the driving motor that drives the developing roller 4a.

The rotation speed of the developing roller 4a is integrated without being reset from when the developing device 4 starts to be used. The remaining usage amount of the developing roller 4a is 100% of the state of the developing device 4 when the developing device 4 starts to be used. In addition, a state where fogging may occur due to toner deterioration or a state where image defects such as vertical stripes may occur is defined as 0%. The remaining usage amount of the developing roller 4a can be expressed by the following equation.

Remaining usage amount of developing roller 4a = 100−integrated rotational speed of developing roller 4a ÷ total rotational speed of developing roller 4a that may cause image defect × 100 (%)

The remaining usage amount of the developing roller 4a is written by the control unit 10 into the storage device 6b (6by to 6bk). If necessary, the apparatus main body of the image forming apparatus S refers to the remaining usage amount of the developing roller 4a from the storage device 6b. The remaining usage amount of the developing roller 4a is derived from the accumulated number of rotations of the developing roller 4a based on a program stored in the storage device 6b.
In the description so far, the remaining usage amount that can be used by the developing roller 4a is used as the usage amount of the developing roller. However, the integrated rotation speed side of the developing roller 4a may be used as the usage amount of the developing roller. For example, when the developing roller is set to be changed to 10,000 rotations, if the developing roller has already made 8000 rotations, the remaining usable amount of the developing roller is 20%. On the other hand, 8000 rotations that have already been rotated become 80%. This may be used.
In addition, the remaining use amount is set to 0% in a state where fogging may occur due to toner deterioration or the like, and a state where image defects such as vertical stripes may occur. However, the developing roller is based on other reasons. It is also possible to set a remaining usage amount that can be used better by exchanging.

<Toner supply operation based on developing roller usage>
In the prior art, toner is supplied from a process cartridge having a large amount of toner to a cleaning blade in a process cartridge having a small amount of toner. However, in this embodiment, attention is paid to the lubricity (toner deterioration state) of the toner supplied to the cleaning blade. This is because the friction coefficient μ between the cleaning blade and the photosensitive drum varies depending on the deterioration state of the toner supplied to the cleaning blade. Here, the deterioration of the toner is caused by the rubbing between the developing blade and the developing roller.

In this embodiment, the degree of toner deterioration is estimated based on the number of rotations of the developing roller 4a. Specifically, the storage device 6b stores the correspondence between the usage amount of the developing device 4 and the degree of toner deterioration. Then, the control unit 10 estimates (acquires) the degree of deterioration of the toner stored in the developing device 4 based on the usage amount of the developing device 4 and the correspondence relationship. Then, the process cartridge C that supplies the toner is determined based on the estimated degree of toner deterioration. Here, the threshold A of the moving distance a of the surface of the photosensitive drum 1 in the circumferential direction of the photosensitive drum 1 is stored in the storage device 6b. In this embodiment, when the moving distance a on the surface of the photosensitive drum 1 exceeds the threshold A, the toner supply operation is executed. Here, the moving distance a of the surface of the photosensitive drum 1 is calculated from the driving time of the driving motor that drives the photosensitive drum 1 and the rotational speed of the photosensitive drum 1. When the control unit 10 executes the program stored in the storage device 6b, the surface of the photosensitive drum 1 is calculated from the driving time of the drive motor and the rotational speed of the photosensitive drum 1 based on the calculation formula stored in the storage device 6b. Is calculated. The moving distance a on the surface of the photosensitive drum 1 is accumulated and stored in the storage device 6b. The moving distance a of the surface of the photosensitive drum 1 is derived from the driving time of the driving motor that drives the photosensitive drum 1 and the rotational speed of the photosensitive drum 1 based on the program stored in the storage device 6b.

  The flow of the toner supply operation will be described with reference to FIG. FIG. 4 is a flowchart illustrating the flow of the toner supply operation according to the first exemplary embodiment. The first embodiment will be described using the process cartridge Cm and the process cartridge Cc as examples. In the first embodiment, the toner supply operation will be described by taking as an example a case where toner is supplied to the cleaning blade 6ac in the process cartridge Cc. In step 101, when the image forming apparatus S receives a print command, the control unit 10 controls the operation of the process cartridge C, whereby the process cartridge C executes a predetermined image forming operation. Here, the control unit 10 controls the operation of the devices in the image forming apparatus S by executing a program stored in the storage device 6b by a CPU (not shown).

  In step 102, after the image forming operation is completed, it is determined from the moving distance a on the surface of the photosensitive drum 1c whether or not the toner supply operation is executed during non-image formation. If the moving distance a of the surface of the photosensitive drum 1c is larger than the threshold value A in step 102, the process proceeds to step 103 (YES in step 102). On the other hand, if the moving distance a of the surface of the photosensitive drum 1c is not larger than the threshold value A in step 102, the process proceeds to step 107 (NO in step 102).

  In step 103, the controller 10 refers to the remaining usage amount of the developing roller 4ac by controlling the operation of the storage device 6b. In step S104, the deterioration level of the toner stored in the process cartridge Cc is compared with the deterioration level of the toner stored in the process cartridge Cm. Specifically, the remaining usage amount of the developing roller 4ac is compared with the remaining usage amount of the developing roller 4am in the process cartridge Cc and the process cartridge Cm.

  For example, it is assumed that the remaining usage amount of the developing roller 4ac in the process cartridge Cc is larger than the remaining usage amount of the developing roller 4am in the process cartridge Cm. At this time, the deterioration degree of the toner in the process cartridge Cc is smaller than the deterioration degree of the toner in the process cartridge Cm. Conversely, it is assumed that the remaining usage amount of the developing roller 4ac in the process cartridge Cc is smaller than the remaining usage amount of the developing roller 4am in the process cartridge Cm. At this time, the deterioration degree of the toner in the process cartridge Cc is larger than the deterioration degree of the toner in the process cartridge Cm.

  If it is determined in step 104 that the deterioration level of the toner in the process cartridge Cc is smaller than the deterioration level of the toner in the process cartridge Cm, the process proceeds to step 105 (YES in step 104). On the other hand, if it is determined in step 104 that the deterioration level of the toner in the process cartridge Cc is larger than the deterioration level of the toner in the process cartridge Cm, the process proceeds to step 106 (NO in step 104).

  In step 105, the control unit 10 controls the operation of the process cartridge Cc to form a toner image on the photosensitive drum 1c. Thus, the toner is supplied to the cleaning blade 6ac in the process cartridge Cc. Specifically, the control unit 10 controls operations of the photosensitive drum 1c, the charging roller 2c, and the developing device 4c (second developing device) in the process cartridge Cc. This toner supply operation corresponds to the above-described “operation for supplying toner at the time of non-image formation in one station”.

In step 106, the control unit 10 controls the operation of the process cartridge Cm to form a toner image on the photosensitive drum 1m. Next, the control unit 10 controls the operations of the photosensitive drum 1m, the intermediate transfer member 7, and the first transfer roller 5m, whereby the toner image on the photosensitive drum 1m is transferred to the intermediate transfer member 7. Then, the control unit 10 controls the operations of the photosensitive drum 1c, the intermediate transfer member 7, and the first transfer roller 5c, thereby transferring (reversely transferring) the toner image on the intermediate transfer member 7 to the photosensitive drum 1c. Thus, the toner is supplied to the cleaning blade 6ac in the process cartridge Cc. This toner supply operation corresponds to the above-described “operation for supplying toner to other stations during non-image formation”.

  In step 107, the control unit 10 controls the operation of the main motor of the photosensitive drum 1c, whereby the photosensitive drum 1c rotates (post-rotation operation) for a predetermined period. In step 108, the control unit 10 controls the operation of the storage device 6b, thereby updating the usage amount of the developing device 4c and resetting the moving distance a on the surface of the photosensitive drum 1c. That is, in this embodiment, the toner supply operation is executed when the moving distance a of the surface of the photosensitive drum 1c exceeds the threshold during the period when the toner supply operation is not executed. In step 109, the control unit 10 controls the operation of the image forming apparatus S, thereby ending the image forming operation.

  In the first exemplary embodiment, the toner supply operation has been described using the process cartridge Cm and the process cartridge Cc as examples. However, the same operation can be performed in the process cartridges Cy to Ck. For example, toner can be supplied from the process cartridge C having the lowest toner deterioration degree to the process cartridge C having the highest toner deterioration degree among the process cartridges Cy to Ck. It is also possible to supply toner from one process cartridge C to a plurality of process cartridges C. Further, toner can be supplied from a plurality of process cartridges C to one process cartridge C.

  Further, it is not always necessary to use the moving distance a of the surface of the photosensitive drum 1 as a trigger for executing the toner supply operation. For example, the remaining usage amount of the developing roller 4a may be used as a trigger for executing the toner supply operation. In the toner supply operation, for example, the process cartridge C that supplies toner can be selected based on the environment in which the image forming apparatus S is used.

<Confirmation of effect>
The case where the toner supply operation is executed when an image is formed on 50 letter papers was examined. The verification was performed in a low temperature and low humidity environment. A solid black image was formed on the photosensitive drum 1 in order to supply toner to the cleaning blade 6a. This time, the case where the length of the solid black image in the sub-scanning direction is 20 mm and the case where it is 80 mm was verified.

  In this verification, in the process cartridge Cm, the remaining usage amount of the developing roller 4am is 70%. In the process cartridge Cc, the remaining usage amount of the developing roller 4ac is 5%. Therefore, the toner in the process cartridge Cm is supplied to the cleaning blade 6ac in the process cartridge Cc.

The verification results are shown in Table 1. As shown in Table 1, abnormal noise was generated when a solid black image having a length of 20 mm was formed with toner having a remaining usage amount of the developing roller of 5%. This is because the lubricity of the toner supplied to the cleaning blade 6ac is low, and the frictional force between the cleaning blade 6ac and the photosensitive drum 1c is high. However, when the length of the solid black image in the sub-scanning direction is increased to 80 mm, no abnormal noise is generated. On the other hand, when the toner whose remaining usage amount of the developing roller is 70% was supplied, no abnormal noise was generated even when the length of the solid black image in the sub-scanning direction was 20 mm.
(Table 1) Abnormal noise occurrence

As described above, in this embodiment, toner is supplied from the process cartridge C having a small degree of deterioration of the stored toner to the cleaning blade 6a in the process cartridge C having a high degree of deterioration of the stored toner. As a result, toner with high lubricity can be supplied to the cleaning blade 6a, and even with a small amount of toner, it is possible to effectively suppress abnormal noise caused by the contact between the cleaning blade 6a and the photosensitive drum 1.
In this embodiment, the toner supply operation is executed based on the moving distance of the surface of the photosensitive drum 1 in the circumferential direction of the photosensitive drum 1. In this embodiment, the increase in the frictional force between the photosensitive drum and the cleaning blade 6a is estimated from the moving distance of the surface of the photosensitive drum 1.

(Example 2)
In the second embodiment, the degree of toner deterioration is estimated based on the remaining amount of toner and the number of rotations of the developing roller. As described above, the toner deteriorates by rubbing against the developing blade. Further, when the amount of toner in the developing device 4 (in the developing device) in the process cartridge C becomes small, the frequency with which the toner slides on the developing blade increases. Therefore, the degree of toner deterioration also changes depending on the amount of toner in the process cartridge C.

  In this embodiment, the remaining amount of toner is detected based on the image information. In the electrophotographic image forming apparatus S, the exposure device 3 exposes the photosensitive drum 1 based on image information. As a result, an electrostatic latent image is formed on the photosensitive drum 1. Then, toner adheres to the electrostatic latent image formed on the photosensitive drum 1, thereby forming a toner image on the photosensitive drum 1. Therefore, in this embodiment, the toner consumption is estimated by integrating the pixel count number that is the number of pixel signals of the image information and multiplying the pixel count number by the toner consumption amount per pixel. The pixel count number is integrated without being reset after the exposure apparatus 3 starts to be used. The remaining amount of toner is derived from the toner consumption per pixel and the pixel count number based on the program stored in the storage device 6b.

Here, the toner consumption can be expressed by the following equation.

Toner consumption = Total pixel count x Toner consumption per pixel

Then, the toner consumption amount is subtracted from the toner amount in the process cartridge C when the process cartridge C is not used. Thus, the amount of toner remaining in the process cartridge C is estimated.

Here, regarding the remaining amount of toner, the remaining amount of toner when the process cartridge C is started to be used is 100%. Further, the remaining amount of toner is set to 0% when there is a possibility that an image defect such as a white spot may occur. The remaining amount of toner can be expressed by the following equation.

Toner remaining amount = 100−toner consumption / initial toner amount × 100 (%)

Further, regarding the usage amount of the developing roller 4a, the usage amount of the developing roller 4a when the process cartridge C is started to be used is set to 0%. Further, the usage amount of the developing roller 4a when there is a risk of image defects such as vertical stripes is set to 100%.

Development roller usage = Integrated rotation speed of the development roller ÷ Total rotation speed of the development roller that may cause image defects x 100 (%)

<Development device usage>
In this embodiment, as shown in FIG. 5, the degree of toner deterioration is determined based on the usage amount of the developing roller 4a and the remaining amount of toner. Specifically, the threshold of the remaining amount of toner is A1, and the threshold of the usage amount of the developing roller is A2. The degree of toner deterioration is divided into four areas. A region where the remaining amount of toner is equal to or greater than the threshold value A1 and the usage amount of the developing roller 4a is smaller than the threshold value A2 is defined as a region 1. Further, an area where the remaining amount of toner is smaller than the threshold value A1 and the usage amount of the developing roller 4a is smaller than the threshold value A2 is defined as an area 2. A region where the remaining amount of toner is equal to or greater than the threshold A1 and the usage amount of the developing roller 4a is equal to or greater than the threshold is defined as region 3. A region where the remaining amount of toner is smaller than the threshold A1 and the usage amount of the developing roller 4a is equal to or greater than the threshold A2 is defined as a region 4. Here, in the second embodiment, parts having the same functions as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In this embodiment, it is assumed that the deterioration degree of the toner is smaller in the region 1 among the four regions. It is assumed that the degree of toner deterioration increases in the order of region 1 → region 2 → region 3 → region 4. That is, the degree of toner degradation in region 4 is the largest. Accordingly, the toner has the highest lubricity in the region 1. The toner lubricity decreases in the order of region 1 → region 2 → region 3 → region 4. The toner in area 4 has the lowest lubricity.

<Toner supply operation based on remaining toner amount and usage amount of developing roller>
A toner supply operation based on the remaining amount of toner and the usage amount of the developing roller will be described. In the present embodiment, as in the first embodiment, the threshold A of the moving distance a on the surface of the photosensitive drum 1 is stored in the storage device 6b. Here, the moving distance a of the surface of the photosensitive drum 1 is calculated from the driving time of the driving motor that drives the photosensitive drum 1 and the rotational speed of the photosensitive drum 1. Further, the moving distance a of the surface of the photosensitive drum 1 is integrated and stored in the storage device 6b.

  The toner supply operation according to the second exemplary embodiment will be described using the process cartridge Cm and the process cartridge Cc as examples. In the second embodiment, the toner supply operation will be described by taking as an example a case where toner is supplied to the cleaning blade 6ac in the process cartridge Cc. In step 201, when the image forming apparatus S receives a print command, the control unit 10 controls the operation of the process cartridge C, whereby the process cartridge C performs a predetermined image forming operation.

  In step 202, after the image forming operation is completed, it is determined from the moving distance a on the surface of the photosensitive drum 1c whether or not the toner supply operation is executed during non-image formation. In step 202, if the moving distance a of the surface of the photosensitive drum 1c is larger than the threshold A, the process proceeds to step 203 (YES in step 102). On the other hand, if the moving distance a of the surface of the photosensitive drum 1c is not greater than the threshold value A in step 202, the process proceeds to step 207 (NO in step 202).

In step 203, the control unit 10 controls the operation of the storage device 6b to refer to the information on the four areas shown in FIG. In step S204, the deterioration level of the toner stored in the process cartridge Cc is compared with the deterioration level of the toner stored in the process cartridge Cm. For example, when the state of the process cartridge Cc is the state of the region 1 and the state of the process cartridge Cm is the state of the region 2, the deterioration degree of the toner in the process cartridge Cc is the deterioration degree of the toner in the process cartridge Cm. It is judged to be lower. Further, when the state of the process cartridge Cc is the state of the region 4 and the state of the process cartridge Cm is the state of the region 3, the deterioration degree of the toner in the process cartridge Cc is the deterioration degree of the toner in the process cartridge Cm. It is judged to be higher.

  If it is determined in step 204 that the deterioration level of the toner in the process cartridge Cc is smaller than the deterioration level of the toner in the process cartridge Cm, the process proceeds to step 205 (YES in step 204). On the other hand, if it is determined in step 204 that the degree of deterioration of the toner in the process cartridge Cc is larger than the degree of deterioration of the toner in the process cartridge Cm, the process proceeds to step 206 (NO in step 204).

  In step 205, the control unit 10 controls the operation of the process cartridge Cc to form a toner image on the photosensitive drum 1c. Thus, the toner is supplied to the cleaning blade 6ac in the process cartridge Cc. Specifically, the control unit 10 controls the operations of the photosensitive drum 1c, the charging roller 2c, and the developing device 4c in the process cartridge Cc. This toner supply operation corresponds to the “operation of supplying toner at the time of non-image formation in one station” described in the first embodiment.

  In step 206, the control unit 10 controls the operation of the process cartridge Cm to form a toner image on the photosensitive drum 1m. Next, the control unit 10 controls the operations of the photosensitive drum 1m, the intermediate transfer member 7, and the first transfer roller 5m, whereby the toner image on the photosensitive drum 1m is transferred to the intermediate transfer member 7. Then, the control unit 10 controls the operations of the photosensitive drum 1c, the intermediate transfer member 7, and the first transfer roller 5c, whereby the toner image on the intermediate transfer member 7 is transferred (reversely transferred) to the photosensitive drum 1c. Thus, the toner is supplied to the cleaning blade 6ac in the process cartridge Cc. This toner supply operation corresponds to the “operation for supplying toner to other stations during non-image formation” described in the first embodiment.

  In step 207, the control unit 10 controls the operation of the main motor of the photosensitive drum 1c, whereby the photosensitive drum 1c rotates (post-rotation operation) for a predetermined period. In step 208, the control unit 10 controls the operation of the storage device 6b to update the usage amount and toner amount of the developing roller 4a, and reset the moving distance a on the surface of the photosensitive drum 1c. In step 209, the control unit 10 controls the operation of the image forming apparatus S to end the image forming operation.

  In the second exemplary embodiment, the toner supply operation has been described using the process cartridge Cm and the process cartridge Cc as examples. However, the same operation can be performed in the process cartridges Cy to Ck. For example, toner can be supplied from the process cartridge C having the lowest toner deterioration degree to the process cartridge C having the highest toner deterioration degree among the process cartridges Cy to Ck. It is also possible to supply toner from one process cartridge C to a plurality of process cartridges C. Further, toner can be supplied from a plurality of process cartridges C to one process cartridge C.

  Further, it is not always necessary to use the moving distance a of the surface of the photosensitive drum 1 as a trigger for executing the toner supply operation. For example, the remaining usage amount of the developing roller 4a may be used as a trigger for executing the toner supply operation. In the toner supply operation, for example, the process cartridge C that supplies toner can be selected based on the environment in which the image forming apparatus S is used.

<Confirmation of effect>
The case where the toner supply operation is executed when an image is formed on 50 letter papers was examined. The verification was performed in a low temperature and low humidity environment. A solid black image was formed on the photosensitive drum 1 in order to supply toner to the cleaning blade 6a. This time, the case where the length of the solid black image in the sub-scanning direction is 30 mm and the case where it is 60 mm was verified.

  In this verification, the usage amount of the developing roller 4am is 90% in the process cartridge Cm. In the process cartridge Cc, the usage amount of the developing roller 4ac is 90%. The remaining amount of toner in the process cartridge Cm is 70%. The remaining amount of toner in the process cartridge Cc is 5%. In this verification, the remaining toner threshold A1 is set to 50%, and the usage threshold A2 of the developing roller 4a is set to 50%. That is, the degree of deterioration of the toner in the process cartridge Cm is the degree of deterioration of the area 3. Further, the deterioration degree of the toner in the process cartridge Cc is the deterioration degree of the region 4. Therefore, this time, the toner in the process cartridge Cm is supplied to the cleaning blade 6ac in the process cartridge Cc.

As shown in Table 2, when a solid black image having a length of 30 mm in the sub-scanning direction was formed and the toner in the deteriorated state of the region 4 was supplied to the cleaning blade 6ac, abnormal noise was generated. This is because the lubricity of the toner is low and the frictional force between the cleaning blade 6ac and the photosensitive drum 1c is high. Furthermore, by forming a solid black image having a length of 60 mm in the sub-scanning direction, abnormal noise was generated even when the toner in the deteriorated state of the region 4 was supplied to the cleaning blade 6ac. On the other hand, when the toner in the deteriorated state of the region 3 was supplied to the cleaning blade 6ac, no abnormal noise was generated when the length of the solid black image was 30 mm or 60 mm. This is because the toner in the deteriorated state of the region 3 has high lubricity.
(Table 2) Absence of abnormal noise

表３に示すように、各領域のトナー劣化度について、所望の潤滑性を与えることができるベタ黒画像の長さが分かった。領域１の劣化度であるトナーでは、潤滑性が高いため、ベタ黒画像の長さ１０ｍｍである場合でも異音を防止することができた。一方、領域４の劣化度であるトナーでは、潤滑性が低いため、異音を防止するために、ベタ黒画像の長さを８０ｍｍにする必要があった。 Table 3 shows the length of the solid black image that can provide the desired lubricity for the toner in the degree of deterioration in each region. The desired lubricity is lubricity that does not generate abnormal noise due to contact between the cleaning blade 6ac and the photosensitive drum 1c.
(Table 3) Necessary amount of toner supply for the degree of toner degradation in each area

As shown in Table 3, regarding the degree of toner deterioration in each region, the length of a solid black image that can give desired lubricity was found. Since the toner having the degradation degree in the region 1 has high lubricity, it is possible to prevent abnormal noise even when the solid black image has a length of 10 mm. On the other hand, since the toner having the degree of deterioration in the region 4 has low lubricity, the length of the solid black image needs to be 80 mm in order to prevent abnormal noise.

As described above, in this embodiment, as in the first embodiment, even with a small amount of toner, it is possible to effectively suppress abnormal noise caused by contact between the cleaning blade and the photosensitive drum.
In this embodiment, the degree of toner degradation is divided into regions 1 to 4 based on the usage amount of the developing roller 4a and the remaining amount of toner. Thereby, the degree of deterioration of the toner in the process cartridge C can be obtained with higher accuracy.

(Other examples)
<1. Timing of control>
In the second embodiment, toner is supplied from the process cartridge C having a low degree of deterioration of the stored toner to the process cartridge C having a high degree of deterioration of the stored toner. However, for example, when the deterioration degree of the toner becomes the deterioration degree of the region 4, it can be controlled so that the toner is supplied from the process cartridge C in which the deterioration degree of the stored toner is low. That is, it is possible to control so that the toner is supplied from another process cartridge C when the degree of toner deterioration reaches a predetermined region.

<2. Relationship between Process Cartridge C for Supplying Toner and Process Cartridge C for Supplying Toner>
(1) Supplying toner from one process cartridge C to a plurality of process cartridges C For example, in an image forming apparatus having four process cartridges C, there is one process cartridge C in which toner that is the degree of deterioration of region 1 is stored. Suppose that there are three process cartridges in which the toner having the degree of deterioration in the region 4 is stored. In this case, the toner can be supplied from the process cartridge C in which the toner having the degree of deterioration in the region 1 is stored to the cleaning blades 6a in the other three process cartridges C.

(2) Supplying toner from a plurality of process cartridges C to one process cartridge C For example, there are three process cartridges C in which toner having a degree of deterioration in region 1 is stored, and toners having a degree of deterioration in region 4 are stored. Suppose that there is one processed cartridge C. In this case, the toner may be supplied from the three process cartridges C in which the toner having the deterioration degree in the region 1 is stored to the one process cartridge C in which the toner having the deterioration degree in the region 4 is stored.

<3. Based on the distance between the process cartridges C, the process cartridge C that supplies the toner is selected>
(1) When two deterioration levels of the toner stored in the process cartridge C exist in the same area For example, when two deterioration levels of the toner stored in the process cartridge C exist in the area 1, the toner is supplied. The toner can be supplied using a process cartridge C closer to the process cartridge C.

(2) When there are two toners stored in the process cartridge C in different areas, for example, the process cartridge C1 storing the toner that is the deterioration level of the area 1 and the toner that is the deterioration level of the area 3 Is a process cartridge C3 in which is stored. Assume that the process cartridge C to which toner is supplied is closer to the process cartridge C3 than the process cartridge C1. In this case, the toner can be supplied to the process cartridge C using the process cartridge C3.
The combination of the process cartridge that supplies toner and the process cartridge that supplies toner is not limited to this.

In each embodiment, the image forming apparatus S supplies toner using a process cartridge C that can be attached to and detached from the main body of the image forming apparatus S. However, it is not necessarily limited to this. For example, the image forming apparatus S may supply toner using a developing cartridge that can be attached to and detached from the main body of the image forming apparatus S.
In each of the embodiments, a toner image is formed as a supply developer on the photosensitive drum 1 in the process cartridge C in which the degree of deterioration of the stored toner is high. Then, the toner is supplied to the cleaning blade 6a in the process cartridge C in which the deterioration degree of the stored toner is low. However, it is not always necessary to form a toner image on the photosensitive drum 1 in the process cartridge C where the degree of deterioration of the stored toner is high. For example, the toner as the supplied developer may be simply carried on the photosensitive drum 1 in the process cartridge C in which the degree of deterioration of the stored toner is high. The method is not limited as long as the toner can be supplied to the cleaning blade 6a in the process cartridge C in which the degree of deterioration of the stored toner is low.

  In each embodiment, the photosensitive drum 1y, the charging roller 2y, the developing device 4y, and the cleaning device 6y are integrated as a process cartridge C. However, it is not necessarily limited to this. For example, a drum unit having the photosensitive drum 1 and a developing unit that is a unit for developing an electrostatic latent image on the photosensitive drum 1 can be separately attached to and detached from the apparatus main body of the image forming apparatus S. Also good.

1 ... photosensitive drum, 4 ... developing device, 6a ... cleaning blade, storage device ... 6b,
7 ... Intermediate transfer member, 10 ... Control unit, A ... Image forming apparatus, C ... Process cartridge

Claims (15)

An image carrier for carrying an electrostatic image;
A developing device for developing the electrostatic image as a developer image;
A plurality of image forming units having a cleaning member that removes residual developer remaining on the image carrier after the developer image is transferred to the transfer body by contacting the image carrier;
A storage device for storing the deterioration degree of the developer based on the usage amount of the developing device;
A control unit that performs a supply operation of supplying a developer to the cleaning member,
The control unit supplies the supplied developer to an image carrier of an image forming unit having a small degree of deterioration of the stored developer among the plurality of image forming units based on the degree of deterioration of the developer, and then The supplied developer is moved to an image carrier of an image forming unit having a large degree of deterioration of the stored developer among the image forming units, and the supply and development is performed on a cleaning member in the image forming unit having a large degree of deterioration of the developer. An image forming apparatus that performs a supply operation for removing the agent. An intermediate transfer member onto which the developer image formed on the image carrier is transferred;
A secondary transfer member for secondary transfer of the developer image primarily transferred to the intermediate transfer member to a recording medium;
The image forming apparatus according to claim 1, further comprising: The control unit controls the operation of the image forming unit,
The supplied developer is supplied from the image carrier to the intermediate transfer member in the image forming unit in which the deterioration degree of the stored developer is small, and the supplied developer supplied to the intermediate transfer member is stored. The developer is transferred to the image carrier in the image forming unit having a large degree of deterioration, and the supplied developer is removed by the cleaning member in the image forming unit in which the degree of deterioration of the stored developer is large. The image forming apparatus according to claim 2.   The image forming apparatus according to claim 2, further comprising a primary transfer member that primarily transfers a developer image formed on the image carrier to the intermediate transfer member. The storage device stores a correspondence relationship between the usage amount of the developing device and the degree of deterioration of the developer,
The said control part acquires the deterioration degree of the developer accommodated in the said developing device based on the usage-amount of the said developing device, and the said correspondence, The any one of Claim 1 to 4 characterized by the above-mentioned. The image forming apparatus described in 1. The image carrier is a photosensitive drum,
The controller is
Obtaining the moving distance of the surface of the photosensitive drum in the circumferential direction of the photosensitive drum;
The image forming apparatus according to claim 5, wherein the supply operation is executed based on the acquired movement distance.   The image forming apparatus according to claim 6, wherein the control unit executes the supply operation when the moving distance in a period in which the supply operation is not performed exceeds a threshold value. The developing device has a developing roller for supplying a developer to the electrostatic latent image on the image carrier,
The image forming apparatus according to claim 5, wherein the control unit acquires a usage amount of the developing device based on a total number of rotations of the developing roller. The controller is
Obtaining the remaining amount of developer in the developing device;
The image forming apparatus according to claim 8, wherein a usage amount of the developing device is acquired based on a remaining amount of the developer in the developing device. The controller is
Based on the usage amount of the developing roller based on the total number of rotations of the developing roller and the remaining amount of the developer in the developing device, the deterioration degree of the developer is determined based on the remaining amount of the developer in the developing device. A first deterioration degree that is greater than or equal to a threshold value and that uses less amount of the developing roller than the threshold value, a remaining amount of developer in the developing device is less than the threshold value, and the used amount of the developing roller is less than the threshold value. 2 a degree of deterioration, a third degree of deterioration in which the remaining amount of developer in the developing device is greater than or equal to a threshold, and a usage amount of the developing roller is greater than or equal to a threshold, and a remaining amount of developer in the developing device is a threshold And a fourth deterioration degree in which the usage amount of the developing roller is equal to or greater than a threshold value,
The first deterioration degree is less deteriorated than the second deterioration degree, the second deterioration degree is less than the third deterioration degree, and the third deterioration degree is deteriorated more than the fourth deterioration degree. The image forming apparatus according to claim 9, wherein the degree is estimated to be small. When the deterioration degree of the developer in a plurality of the developing devices is divided into the same deterioration degree,
The supplied developer is supplied to the image forming unit in which the distance to which the supplied developer is transported is shortest among the image forming units in which the developer classified into the same deterioration degree is stored. The image forming apparatus according to claim 10.   The control unit executes the supply operation so that the developer is supplied from the developing device in one image forming unit to the cleaning member in the plurality of image forming units. 12. The image forming apparatus according to any one of items 1 to 11.   The control unit executes the supply operation so that the developer is supplied from the developing devices in the plurality of image forming units to the cleaning member in one image forming unit. 12. The image forming apparatus according to any one of items 1 to 11.   The image forming apparatus according to claim 1, wherein the storage device is provided in the image forming unit. A first image carrier for carrying a first electrostatic image;
A second image carrier for carrying a second electrostatic image;
A first developing device for developing the first electrostatic image as a developer image;
A second developing device for developing the second electrostatic image as a developer image;
A first cleaning member that contacts the first image carrier to remove residual developer remaining on the first image carrier after the developer image is transferred to the transfer member;
A second cleaning member that removes residual developer remaining on the second image carrier after the developer image is transferred to the transfer body by contacting the second image carrier;
Based on the first deterioration level of the developer based on the usage amount of the first developing device and the second deterioration level of the developer based on the usage amount of the second developing device, the developer is applied to the second cleaning member. A control unit that performs a supply operation to supply,
The control unit supplies the supplied developer from the first developing device to the first image carrier when the second degradation degree is greater than the first degradation degree, and then the second image carrier. The image forming apparatus, wherein the supply developer is moved to supply the supply developer to the second cleaning member.

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