阅读说明：本技术 成像单元和成像装置 (Image forming unit and image forming apparatus ) 是由 草野洋平 清水宏树 竹内俊阳 角田秀树 于 2020-09-16 设计创作，主要内容包括：提供一种用于在成像装置中使用的成像单元,该成像单元包括：感光单元,该感光单元包括图像承载部件；显影单元,该显影单元包括显影剂承载部件和能够容纳显影剂的容器；旋转轴,显影单元绕该旋转轴旋转,并位于显影位置和分离位置中的一个处,在显影位置中,显影剂承载部件将显影剂供给至图像承载部件,在分离位置中,显影剂承载部件与图像承载部件分离；以及检测部分,该检测部分检测与容纳在显影单元中的显影剂的量相对应的变化或量。沿重力方向,旋转轴位于由图像承载部件和显影剂承载部件形成的显影部分的下方,以及其中,当显影单元处于分离位置时,检测部分限制显影单元的旋转,从而从显影单元接收力。以及一种成像装置。(There is provided an image forming unit for use in an image forming apparatus, the image forming unit including: a photosensitive unit including an image bearing member; a developing unit including a developer bearing member and a container capable of containing a developer; a rotary shaft around which the developing unit rotates and which is located at one of a developing position in which the developer bearing member supplies the developer to the image bearing member and a separating position in which the developer bearing member is separated from the image bearing member; and a detecting portion that detects a change or an amount corresponding to an amount of the developer accommodated in the developing unit. The detection portion restricts rotation of the developing unit when the developing unit is at the separated position, thereby receiving a force from the developing unit. And an image forming apparatus.)

1. An imaging unit for use in an imaging device, the imaging unit comprising:

a photosensitive unit including an image bearing member;

a developing unit including a developer bearing member and a container capable of containing a developer;

a rotary shaft around which the developing unit rotates and which is located at one of a developing position in which the developer bearing member supplies the developer to the image bearing member and a separating position in which the developer bearing member is separated from the image bearing member; and

a detecting portion that detects a variation or an amount corresponding to an amount of the developer accommodated in the developing unit;

wherein the rotation shaft is located below a developing portion formed by the image bearing member and the developer bearing member in a gravitational direction, and

wherein the detecting portion restricts rotation of the developing unit when the developing unit is at the separated position, thereby receiving the force from the developing unit.

2. The imaging unit of claim 1, wherein: the center of gravity of the developing unit is located farther from the developing portion than from the rotation shaft in a horizontal direction perpendicular to the direction of gravity.

3. The imaging unit of claim 1, wherein: the detecting portion restricts rotation of the developing unit when the developing unit is in the separated position, thereby receiving a force based on gravity acting on the developing unit.

4. The imaging unit of claim 1, wherein:

the detecting portion has a contact portion and the developing unit has an opposed contact portion which is brought into contact with the contact portion when the developing unit rotates, an

The detecting portion is provided in an apparatus main body of the image forming apparatus, and detects a change or an amount based on a force applied by the developing unit when the contact portion is in contact with the opposing contact portion.

5. The imaging unit of claim 4, wherein: the detecting portion optically detects a movement amount of the developing unit to use the detected movement amount as the change.

6. The imaging unit of claim 5, wherein:

the detection section includes: an optical detection member provided with a plurality of lines in a direction intersecting a direction in which the developing unit rotates; and an optical sensor, a relative positional relationship between the optical detection member and the optical sensor being changed with rotation of the developing unit, an

The optical sensor calculates the number of lines passed when the developing unit rotates due to its weight, and uses the calculated number of lines as the change.

7. The imaging unit of claim 5, wherein: the detecting portion detects a load applied by the developing unit on the detecting portion, and uses the detected load as the amount.

8. The imaging unit of claim 7, wherein: the detection portion is a load unit that detects a load applied to the contact portion by the opposing contact portion.

9. The imaging unit of claim 1, further comprising: a control portion that calculates a remaining toner amount, which is an amount of the developer contained in the developing unit, based on the change or amount detected by the detection portion.

10. The imaging unit according to claim 1, the rotational shaft rotatably coupling the developing unit with the photosensitive unit.

11. An image forming apparatus comprising:

an image forming unit that develops an electrostatic latent image formed on an image bearing member by using a developer; and

a transfer portion that transfers the image developed by the image forming unit onto a recording material;

the imaging unit is according to any one of claims 1 to 10.

Technical Field

The present invention relates to an image forming unit and an image forming apparatus.

Background

In an image forming apparatus (e.g., a printer) using an electrophotographic image forming method (electrophotographic process), when an image is formed on a recording material, first, each photosensitive drum is uniformly charged by a charging roller. Then, an electrostatic latent image is formed on the photosensitive drum by selective exposure of the charged photosensitive drum by an exposure device. The electrostatic latent image formed on the photosensitive drum is developed into a toner image by a developing device using toner. Then, the toner image formed on the photosensitive drum is transferred onto a recording material (e.g., a recording sheet or a plastic sheet). The toner image transferred onto the recording material is heated/pressurized by a fixing unit so as to be fixed on the recording material. Thus, an image is formed on the recording material. After the toner image is transferred onto the recording material, the toner remaining on the photosensitive drum is removed by a cleaning blade.

In order to easily maintain the process devices (e.g., the photosensitive drum, the charging roller, and the developing device), a process cartridge is used in such an image forming apparatus. The process cartridge is a member obtained by integrating respective process means (e.g., a photosensitive drum, a charging roller, a cleaning blade, and a developing device) with one another in a cartridge. The process cartridge is detachable from an apparatus main body of the image forming apparatus. Therefore, by replacing the process cartridge, the process apparatus can be easily maintained.

There is known a configuration of an image forming apparatus from which a process cartridge is detachable and which has a remaining toner amount detecting mechanism capable of sequentially detecting the amount of remaining toner (patent document 1: japanese patent application laid-open No. h 09-114225).

In such an image forming apparatus, the developer bearing member of the developing unit is always biased toward the photosensitive drum of the drum unit by a spring. Therefore, the biasing force, the weight of the developing unit, and the pressing force determined by the weight of the toner are applied from the developer bearing member to the photosensitive drum. The remaining toner amount detecting mechanism in patent document 1 measures the pressing force in order to detect the amount of remaining toner.

Disclosure of Invention

The remaining toner amount detecting mechanism in patent document 1 sequentially measures a pressing force from the developing device during operation of the developing device, and calculates the amount of remaining toner based on the pressing force. Then, the remaining toner amount detecting mechanism displays the calculated remaining toner amount so that the user can recognize the remaining toner amount.

However, since the remaining toner amount detecting mechanism in patent document 1 measures the pressing force including the toner weight, the fluctuation of the pressing force may affect the measurement of the remaining toner amount. In addition, since the remaining toner amount detecting mechanism is configured such that, in the process cartridge, the developer carrying member is always biased toward the photosensitive drum by the pressing force including the weight of the toner, when creep deformation or the like is generated in the frame body, the measurement of the remaining toner amount may be affected by the creep deformation.

The present invention has been made in view of solving the above-mentioned problems, and an object of the present invention is to provide a technique of accurately measuring a remaining toner amount in a process cartridge or a value related to the remaining toner amount.

The present invention provides an image forming unit for use in an image forming apparatus, the image forming unit including:

a photosensitive unit including an image bearing member;

a developing unit including a developer bearing member and a container capable of containing a developer;

a rotary shaft around which the developing unit rotates and which is located at one of a developing position in which the developer bearing member supplies the developer to the image bearing member and a separating position in which the developer bearing member is separated from the image bearing member; and

a detecting portion that detects a variation or an amount corresponding to an amount of the developer accommodated in the developing unit;

wherein the rotation shaft is located below a developing portion formed by the image bearing member and the developer bearing member in a gravitational direction, and

wherein the detecting portion restricts rotation of the developing unit when the developing unit is at the separated position, thereby receiving the force from the developing unit.

Further features of the invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

Drawings

Fig. 1A is a sectional view of a remaining toner amount detecting unit during image formation according to the first embodiment;

fig. 1B is a sectional view of a remaining toner amount detecting unit during measurement of a remaining toner amount according to the first embodiment;

fig. 1C is a sectional view of a remaining toner amount detecting unit during development separation according to the first embodiment;

fig. 2 is a sectional view showing a schematic configuration of an image forming apparatus according to the first embodiment;

fig. 3 is a sectional view of the process cartridge according to the first embodiment;

fig. 4A and 4B are perspective views of the process cartridge according to the first embodiment as viewed from the bottom surface side and the top surface side;

fig. 5A to 5E are views of a remaining toner amount detecting unit according to the first embodiment;

fig. 6A and 6B are graphs showing the relationship among the remaining toner amount, pressing force, and number of pulses according to the first embodiment;

fig. 7A is a sectional view of a remaining toner amount detecting unit during image formation according to the second embodiment;

fig. 7B is a sectional view of the remaining toner amount detecting unit during measurement of the remaining toner amount according to the second embodiment;

fig. 7C is a sectional view of the remaining toner amount detecting unit during development separation according to the second embodiment;

fig. 8A is an enlarged view of the remaining toner amount detection unit during image formation according to the first embodiment;

fig. 8B is an enlarged view of the remaining toner amount detection unit during remaining toner amount measurement according to the first embodiment; and

fig. 8C is an enlarged view of the remaining toner amount detection unit during development separation according to the first embodiment.

Detailed Description

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. However, the size, material, shape, relative position, and the like of the components described in the embodiments are not intended to limit the scope of the present invention unless otherwise specifically stated.

First embodiment

The general configuration of an image forming apparatus 100 according to the first embodiment will be described below with reference to fig. 2. Fig. 2 is a sectional view schematically showing the image forming apparatus 100 according to the first embodiment. In the first embodiment, each process cartridge 1 (image forming unit) and each toner cartridge 13 are detachable from the apparatus main body 101 of the image forming apparatus 100.

In the first embodiment, the configurations and operations of the first to fourth image forming sections are substantially the same except that images to be formed have different colors. Therefore, when it is not necessary to particularly distinguish the respective image forming portions from each other, the configurations and operations of the first to fourth image forming portions will be generally described by omitting the marks Y to K.

The first to fourth process cartridges 1 are arranged to be arranged in the horizontal direction. Each process cartridge 1 is formed of a photosensitive unit 4 and a developing unit 6.

The photosensitive unit 4 includes: a photosensitive drum 7, the photosensitive drum 7 serving as an image bearing member; a charging roller 8, the charging roller 8 serving as a charging means for uniformly charging the surface of the photosensitive drum 7; and a cleaning blade 10, the cleaning blade 10 serving as a cleaning means.

The developing unit 6 is a developing device including a developing roller 11 and a container, the developing roller 11 serving as a developer bearing member, the container being capable of containing a developer T (hereinafter referred to as toner). The developing unit 6 supplies toner to develop the electrostatic latent image formed on the photosensitive drum 7. The photosensitive unit 4 and the developing unit 6 are supported to be swingable (rotatable) relative to each other.

It should be noted that the first process cartridge 1Y accommodates yellow (Y) toner in the developing unit 6. Similarly, the second process cartridge 1M contains magenta (M) toner, the third process cartridge 1C contains cyan (C) toner, and the fourth process cartridge 1K contains black (K) toner.

Each process cartridge 1 is detachable from the image forming apparatus 100 by an attaching means provided in the image forming apparatus 100, such as an attaching guide (not shown) and a positioning member (not shown). A scanner unit 12 for forming an electrostatic latent image is disposed below each process cartridge 1. In addition, in the image forming apparatus, the waste toner conveying unit 23 is disposed behind each process cartridge 1 (downstream of the process cartridge 1 in the direction of attachment/detachment of the process cartridge 1).

The first to fourth toner cartridges 13 are arranged to be arranged below the process cartridge 1 in the horizontal direction in the following order: the first to fourth toner cartridges 13 correspond to colors of toners accommodated in the respective process cartridges 1. Specifically, the first toner cartridge 13Y accommodates yellow (Y) toner. Likewise, the second toner cartridge 13M contains magenta (M) toner, the third toner cartridge 13C contains cyan (C) toner, and the fourth toner cartridge 13K contains black (K) toner. Each toner cartridge 13 supplies toner to the process cartridge 1 accommodating the same color toner.

Each toner cartridge 13 performs an operation of resupplying toner when a remaining toner amount detecting unit 70 (to be described later) provided in the apparatus main body 101 of the image forming apparatus 100 detects that the amount of toner remaining in the process cartridge 1 is insufficient or in order to keep the remaining toner amount constant. The toner cartridge 13 can be detached from the image forming apparatus 100 by an attaching means provided in the image forming apparatus 100, such as an attaching guide (not shown) and a positioning member (not shown). It should be noted that details of the process cartridge 1 and the toner cartridge 13 will be described later.

The first to fourth toner conveying devices 14 are arranged below the toner cartridges 13 so as to correspond to the respective toner cartridges 13. Each toner conveying device 14 conveys toner received from the corresponding toner cartridge 13 upward to supply the toner to the corresponding developing unit 6.

An intermediate transfer unit 19 is provided above the process cartridge 1 so as to function as an intermediate transfer member. First to fourth primary transfer portions (image forming portions) S1Y to S1K are formed between the intermediate transfer unit 19 and the first to fourth process cartridges 1Y to 1K. The intermediate transfer unit 19 is arranged substantially horizontally with its primary transfer portion S1 side facing downward.

The intermediate transfer belt 18 facing each photosensitive drum 7 is a rotatable endless belt wound in tension around a plurality of winding rollers. A primary transfer roller 20 is disposed on the inner surface of the intermediate transfer belt 18 so as to serve as a primary transfer member. The respective primary transfer rollers 20 form primary transfer portions S1Y to S1K via the intermediate transfer belt 18 between the primary transfer rollers 20 and the respective photosensitive drums 7.

The secondary transfer roller 21 serving as a secondary transfer member is in contact with the intermediate transfer belt 18 to form a secondary transfer portion S2 together with the roller facing it via the intermediate transfer belt 18. In addition, in the left-right direction (the direction in which the intermediate transfer portion S2 and the intermediate transfer belt 18 are stretched with tension), the intermediate transfer belt cleaning unit 22 is arranged to oppose the secondary transfer portion S2.

The fixing unit 25 is disposed above the intermediate transfer unit 19. The fixing unit is configured to include a heating unit 26 and a pressure roller 27, and the pressure roller 27 is to be in press contact with the heating unit. The discharge tray 32 is disposed on the upper surface of the apparatus main body 101. The waste toner collecting container 24 is disposed between the discharge tray 32 and the intermediate transfer unit. A paper feed tray 2 for accommodating a recording material 3 is disposed in the lowermost portion of the apparatus main body 101.

The image forming apparatus 100 includes a control section 120. The control section 120 is connected to each component via a control line, not shown, so as to control operation timing related to an image forming operation and perform an operation for forming an image according to image data or the like in response to an instruction from a user or an instruction from a program developed in a memory. The control section 120 may also perform various arithmetic processes according to the present invention (for example, calculating a pressing force or a remaining toner amount). A processing device having arithmetic resources (e.g., a processor and a memory) can be used as the control section 120.

The image forming apparatus 100 includes a power supply section 150. The power supply portion 150 is a high-voltage power supply device, and supplies power required for the driving device. The image forming apparatus 100 includes a driving portion 170. The driving portion 170 is a driving mechanism including a motor or the like for converting electric power into driving force, and serves as a power source for rotation of various rollers or the like.

Imaging process

An image forming operation in the image forming apparatus 100 will be described below with reference to fig. 2 and 3.

Fig. 3 is a sectional view of each process cartridge 1 according to the first embodiment.

During image formation, each photosensitive drum 7 is driven to rotate at a predetermined speed in the direction indicated by the arrow a in fig. 3. The intermediate transfer belt 18 is driven to rotate in a direction indicated by an arrow B in fig. 2 (forward direction with respect to the rotational direction of the photosensitive drum 7).

First, the surface of each photosensitive drum 7 is uniformly charged by the charging roller 8. Then, the laser light emitted from the scanner unit 12 scans/exposes the surface of the photosensitive drum 7, so as to form an electrostatic latent image based on image information on the photosensitive drum 7. The electrostatic latent image formed on the photosensitive drum 7 is developed into a toner image by the developing unit 6. At this time, the developing units 6 are pressed by the corresponding one of the developing/pressing units 38 provided in the main body of the image forming apparatus 100. Then, the toner image formed on the photosensitive drum 7 is primarily transferred onto the intermediate transfer belt 18 by the primary transfer roller 20. The developing/pressing unit 38 is moved rightward in the drawing to press the developing unit 6, and the pressing force is generated to bring the developing roller 11 into contact with the photosensitive drum 7.

For example, in the process of forming a full-color image, the above-described processes are sequentially performed in the first to fourth primary transfer portions (image forming portions) S1Y to S1K. As a result, the toner images of the respective colors are sequentially stacked on the intermediate transfer belt 18.

Meanwhile, in synchronization with the movement of the intermediate transfer belt 18, the recording material 3 accommodated in the paper feed tray 2 is fed at a predetermined control timing so as to be conveyed to the secondary transfer portion S2. Then, the four color toner images on the intermediate transfer belt 18 are simultaneously secondary-transferred onto the recording material 3 by the secondary transfer roller 21, and the secondary transfer roller 21 is in contact with the intermediate transfer belt 18 via the recording material 3.

Then, the recording material 3 on which the toner image is transferred is conveyed to a fixing unit 25. The toner image is fixed on the recording material 3 by heating/pressing the recording material 3 in the fixing unit 25. Then, the recording material 3 having the fixed toner image is conveyed to the discharge tray 32, thereby completing the image forming operation.

The post-primary transfer residual toner (waste toner) remaining on the photosensitive drum 7 after the primary transfer step is removed by a cleaning blade 10. The post-secondary transfer residual toner (waste toner) remaining on the intermediate transfer belt 18 after the secondary transfer step is removed by an intermediate transfer belt cleaning unit 22. The waste toner removed by the cleaning blade 10 and the intermediate transfer belt cleaning unit 22 is conveyed by a waste toner conveying unit 23 provided in the apparatus main body 101 and stored in a waste toner collecting container 24. It should be noted that the imaging device 100 is configured to be able to also form a monochromatic or polychromatic image by using only one or some (but not all) of the desired imaging portions.

Processing box

The general configuration of each process cartridge 1 to be attached to the image forming apparatus 100 according to the first embodiment will be described below with reference to fig. 3, 4A, and 4B. Fig. 4A is a perspective view of the process cartridge 1 as viewed from the bottom surface side. Fig. 4B is a perspective view of the process cartridge 1 as viewed from the top surface side.

Each process cartridge 1 is formed of a photosensitive unit 4 and a developing unit 6. The photosensitive unit 4 and the developing unit 6 are connected to be swingable (rotatable) about a rotation support pin 30 (rotation shaft).

The photosensitive unit 4 includes a photosensitive unit frame body 5, and the photosensitive unit frame body 5 supports various components in the photosensitive unit 4. Inside the photosensitive unit 4, not only the photosensitive drum 7, the charging roller 8, and the cleaning blade 10, but also a waste toner transport screw 15 is provided, the waste toner transport screw 15 extending in a direction parallel to the rotational axis direction of the photosensitive drum 7. In the photosensitive unit frame body 5, cleaning bearings 33 are disposed at both longitudinal ends of the photosensitive unit 4, and the cleaning bearings 33 include a row of cleaning gears for rotatably supporting the photosensitive drum 7 and transmitting drive from the photosensitive drum to the waste toner conveying screw 15.

The charging roller 8 provided in the photosensitive unit 4 is biased in a direction (direction indicated by arrow C) toward the photosensitive drum 7 by charging roller pressing springs 36 arranged at both ends of the charging roller 8. The charging roller 8 is provided to follow the movement of the photosensitive drum 7. When the photosensitive drum 7 is driven to rotate in the direction indicated by the arrow a during image formation, the charging roller 8 rotates in the direction indicated by the arrow D (forward direction of rotation of the photosensitive drum 7).

The cleaning blade 10 provided in each photosensitive unit 4 includes: an elastic member 10a for removing post-transfer residual toner (waste toner) remaining on the surface of the photosensitive drum 7 after primary transfer; and a support member 10b for supporting the elastic member 10 a. The waste toner removed from the surface of the photosensitive drum 7 by the cleaning blade 10 is accommodated in a waste toner accommodating chamber 9 formed by the cleaning blade 10 and the photosensitive unit frame body 5. The waste toner accommodated in the waste toner accommodating chamber 9 is conveyed to the rear side of the image forming apparatus 100 (downstream in the direction of mounting/dismounting the process cartridge 1) by the waste toner conveying screw 15 arranged in the waste toner accommodating chamber 9. The conveyed waste toner is discharged from the waste toner discharging portion 35, and conveyed to the waste toner conveying unit 23 of the image forming apparatus 100.

The developing unit 6 includes a developing frame body 16, and the developing frame body 16 supports various components in the developing unit 6. The developing frame body 16 is divided into a developing chamber 16a and a toner accommodating chamber 16b, the developing roller 11 and the supply roller 17 are provided in the developing chamber 16a, the toner is accommodated in the toner accommodating chamber 16b, and the stirring member 29 is provided in the toner accommodating chamber.

The developing roller 11, the supply roller 17, and the developing blade 28 are provided in the developing chamber 16 a. The developing roller 11 carries toner, rotates in the direction indicated by the arrow E during image formation, and contacts the photosensitive drum 7 to convey the toner to the photosensitive drum 7. The developing roller 11 is supported by the developing frame body 16 at both end portions thereof in the longitudinal direction in a manner capable of rotating by the developing bearing unit 34.

An Oldham (Oldham) unit 50 is disposed in the developing bearing unit 34 of the developing unit 6 so as to receive a driving force from the apparatus main body 101 and transmit the driving force to the supply roller 17 and the developing roller 11. The european style unit 50 serves as a drive interface that receives a driving force from the apparatus main body 101. The european style unit 50 is biased toward the photosensitive-unit frame body 5 (cleaning bearing 33) by a spring, not shown. When the unit frame body 5 is positioned, the reaction force of the unit frame body 5 acts so that the developing unit 6 rotates to be separated from the unit frame body 5. However, the amount of this reaction force is very small compared to the rotational moment when the developing unit 6 rotates about the rotation support pin 30 due to its weight, and is constant regardless of the weight of the remaining toner. Therefore, the reaction force does not affect the detection of the remaining toner amount by the remaining toner amount detecting unit 70.

The supply roller 17 is supported by the developing frame body 16 in a manner capable of rotating by the developing bearing unit 34 while being in contact with the developing roller 11, and rotates in the direction indicated by the arrow F at the time of image formation. In addition, the developing blade 28 is arranged in contact with the surface of the developing roller 11, and the developing blade 28 functions as a layer thickness controlling member that controls the thickness of the toner layer formed on the developing roller 11.

An agitating member 29 is provided in the toner accommodating chamber 16b so as to agitate the accommodated toner, and also to convey the toner to the supply roller 17 via the developing chamber communication port 16 c. The stirring member 29 includes a rotation shaft 29a parallel to the rotation axis direction of the developing roller 11 and a stirring blade 29b (this stirring blade 29b is a flexible blade) serving as a conveying member. One end of each stirring piece 29b is attached to the rotating shaft 29a, and the other end serves as a free end. The rotation shaft 29a rotates so that each stirring piece 29b rotates in the direction indicated by the arrow G, and therefore, the toner is stirred by the stirring piece 29 b.

The developing unit 6 has a developing chamber communication port 16c communicating with each of the developing chamber 16a and the toner accommodating chamber 16 b. In the first embodiment, when the developing unit 6 is in the normal use position (position during use), the developing chamber 16a is located above the toner accommodating chamber 16 b. The toner in the toner containing chamber 16b, which has been pumped by the stirring member 29, is supplied to the developing chamber 16a through the developing chamber communication port 16 c.

In the developing unit 6, a receiving opening 40 is provided in a downstream end thereof in the attachment/detachment direction. A toner-receiving-port shutter 41 and a receiving-port sealing member 45 movable in the front-rear direction are arranged above the toner receiving port 40. When the process cartridge 1 is not attached to the image forming apparatus 100, the toner receiving port 40 is closed by the port shutter 41. The inlet shutter 41 is configured to operate in association with an operation of mounting/dismounting the process cartridge 1, and is biased so as to open toward the image forming apparatus 100.

The receiving conveyance path 42 is provided in communication with the toner receiving port 40. The receiving conveyor screw 43 is disposed inside the receiving conveyor path 42. In addition, an accommodating chamber communication port 44 for supplying toner to the toner accommodating chamber 16b is provided in the vicinity of the longitudinal middle portion of the developing unit 6 so as to provide communication between the receiving conveyance path 42 and the toner accommodating chamber 16 b. The receiving conveyance screws extend parallel to respective directions of the rotational axes of the developing roller 11 and the supply roller 17 so as to convey the toner received from the toner receiving port 40 to the toner accommodating chamber 16b via the accommodating chamber communication port 44.

In the developing unit 6, the center of gravity W is indicated by an arrow. The center of gravity W exists in the toner accommodating chamber 16b with respect to the rotation support pin 30. In addition, the opposed contact portion 37 is arranged to be in contact with a remaining toner amount detection unit 70 (to be described later) provided in the image forming apparatus 100.

It can be said that when the developing roller 11 and the photosensitive drum 7 are in contact, both the developing roller 11 and the photosensitive drum 7 are in the development position where development can be performed. At this time, the respective portions where the developing roller 11 and the photosensitive drum 7 contact are referred to as developing portions. Meanwhile, when both the developing roller 11 and the photosensitive drum 7 are at the separation position where the developing roller 11 and the photosensitive drum 7 are separated from each other, the magnitude of the force corresponding to the weight of the toner can be detected according to the present invention.

A restricted portion 60 and a restricting portion 61 each for determining a separation position at which the developing roller 11 and the photosensitive drum 7 are separated from each other are provided in the developing bearing unit 34 and the photosensitive unit frame body 5 of the developing unit 6, respectively. When the developing roller 11 and the photosensitive drum 7 are separated from each other, the restricted portion 60 comes into contact with the restricting portion 61 of the photosensitive unit frame body 5 positioned in advance, so as to determine the separation position of the developing roller 11 with respect to the photosensitive drum 7.

Here, it is preferable that the rotational support pin 30 is located below the developing portion in the gravity direction. When the biasing force exerted on the photosensitive unit 4 by the developing unit 6 is removed, the developing unit 6 rotates about the rotation supporting pin 30 due to its weight, thereby being located at the separation position. Therefore, the force exerted on the remaining toner amount detecting unit 70 corresponds to a force based on the respective weights of the toner and the container from which the biasing force has been removed.

The position of the center of gravity W needs to be located downstream of the rotation support pin 30 in the horizontal direction perpendicular to the direction of gravity in which the developing roller 11 moves while being separated from the photosensitive drum. In other words, the position of the center of gravity W is farther from the developing portion than the position of the rotation support pin 30 in the above-described horizontal direction. In contrast, in the above-described horizontal direction, the position of the rotation support pin 30 is closer to the developing portion than the position of the center of gravity W. Therefore, when gravity acts on the developing unit 6 containing toner so that the developing unit 6 moves around the rotational support pin 30 and the developing roller 11 is separated from the photosensitive drum 7, the remaining toner amount detecting unit 70 receives a force from the developing unit 6. The received force is derived from a moment corresponding to the amount of remaining toner. The remaining toner amount detecting unit 70 physically changes according to the magnitude of the received force, and detects the resulting change.

It should be noted that, in fig. 3, the rotation support pin 30 (rotation axis) is located between the position of the developing portion and the position of the center of gravity W of the developing unit 6 in the horizontal direction perpendicular to the direction of gravity. Meanwhile, the biasing force applied to the above-described european unit 50 acts to increase the force generated by the moment due to the reaction force received from the cleaning bearing 33. This biasing force is constant regardless of the weight of the toner.

Remaining toner amount detecting unit structure

The configuration of the remaining toner amount detecting unit 70 (detecting portion) is described below with reference to fig. 1A to 1C, fig. 5A to 5E, and fig. 8A to 8C. Fig. 1A is a sectional view of a remaining toner amount detecting unit during image formation in a process cartridge according to a first embodiment. Fig. 1B is a sectional view of the remaining toner amount detecting unit during measurement of the remaining toner amount in the process cartridge according to the first embodiment. Fig. 1C is a sectional view of the remaining toner amount detecting unit during full development separation in the process cartridge according to the first embodiment.

Fig. 5A is a first perspective view of the remaining toner amount detecting unit according to the first embodiment.

Fig. 5B is a first side view of the remaining toner amount detecting unit in the first embodiment. Fig. 5C is a top view (plan view) of the remaining toner amount detecting unit according to the first embodiment. Fig. 5D is a second perspective view of the remaining toner amount detecting unit according to the first embodiment when viewed in a direction different from that in fig. 5A. Fig. 5E is a second side view of the remaining toner amount detecting unit according to the first embodiment when viewed in the direction opposite to fig. 5B.

Fig. 8A is an enlarged view of the remaining toner amount detecting unit during image formation in the process cartridge according to the first embodiment. Fig. 8B is an enlarged view of the remaining toner amount detecting unit during measurement of the remaining toner amount in the process cartridge according to the first embodiment. Fig. 8C is an enlarged view of the remaining toner amount detection unit during development separation in the process cartridge according to the first embodiment.

As shown in fig. 5A, the remaining toner amount detecting unit 70 is configured to include a detecting lever 71, a holder member 72, a spring 73, a slit portion 74 (optical detecting member), and a sensor portion 75 (optical sensor). As shown in fig. 5B and 5E, the sensor portion 75 is configured to include a light emitting portion 75a and a light receiving portion 75B.

As can be seen from comparison between fig. 1A and 1C, the detection lever 71 is held so as to be rotatable about the rotation shaft 71b relative to the holder member 72. As shown in fig. 8A to 8C, the spring 73 is disposed between the boss 71C of the detection lever 71 and the boss 72b of the holder member 72. At this time, the detection lever 71 is always biased toward the abutting portion 72a of the holder member 72 by the biasing force P of the spring 73.

As also shown in fig. 5B, 5D, and 5E, a sheet-like slit portion 74 is attached to the tip of the detection lever 71 so as to extend through the light emitting portion 75a and the light receiving portion 75B of the sensor portion 75 arranged on the holder member 72.

By combining the sensor portion 75 with the slit portion 74, it is possible to measure a mechanical position change of the detection lever 71 due to rotation of the detection lever 71 by the number of times the light received by the light receiving portion 75b is blocked by passing the line, and to allow the control portion 120 to detect the change (position change information) of the detection lever 71.

The slit portions 74 are transparent plate/sheet-like members on which black lines parallel to the Z direction are printed at predetermined intervals. The color of the line on the slit portion 74 is not limited to black as long as a plurality of lines in a color sufficient to block light are provided on the planar member and spaced at predetermined intervals in a direction crossing a direction in which the developing unit moves. In the separated state, the relative positional relationship between the slit portion 74 and the sensor portion 75 varies with the weight size of the developing unit including the toner.

Detection of remaining toner amount

The detection of the remaining toner amount will be described below with reference to fig. 1A to 1C, fig. 2, fig. 6A and 6B, and fig. 8A to 8C. Fig. 6A is a graph showing a relationship between the remaining toner amount (g) in the developer accommodating chamber and the pressing force (N) applied to the opposed contact surface of the developing unit according to the first embodiment. Fig. 6B is a graph showing the relationship between the pressing force (N) applied to the opposed contact surface of the developing unit and the number of pulses as the return value from the remaining toner amount detecting unit according to the first embodiment. The number of pulses corresponds to the number of times of light blocking and light transmission, which are repeatedly performed as the detection lever 71 rotates, wherein the light blocking is a process in which the black line portion of the slit portion 74 blocks light received by the light receiving portion 75b, and the light transmission is a process in which the transparent portion of the slit portion 74 transmits light. The control section 120 detects the value of the number of repetitions so that the change (position change information) of the detection lever 71 can be detected. The relationship shown in fig. 6A and 6B may be suitably stored in the memory of the control section 120 in the form of, for example, a formula or a table so as to be available for arithmetic processing performed by the control section 120.

As can be seen from fig. 6A and 6B, the specific number of pulses corresponds to the remaining toner amount (serving as an amount to be detected). By detecting the specific number of pulses, the control section 120 can perform response processing when a predetermined remaining toner amount is detected. Examples of the response processing when the predetermined remaining toner amount is detected include a report of the remaining toner amount, toner resupply, and the like.

As shown in fig. 2, during image formation in the process cartridge 1, each developing unit 6 is pressed by a developing/pressing unit 38 provided in the main body of the image forming apparatus 100 while the developing roller 11 is in contact with the photosensitive drum 7.

At this time, as shown in fig. 1A and 8A, there is a gap between the contact portion 71A of the detection lever 71 of the remaining toner amount detection unit 70 and the opposed contact portion 37 (each provided in the image forming apparatus 100 main body) of the developing unit 6.

At the same time as the image forming process ends, the pressing by each developing/pressing unit 38 provided in the above-described image forming apparatus 100 main body is released, and the bias of the photosensitive drum 7 by the developing roller 11 is cancelled. Therefore, due to the weight of the developing unit 6, the developing unit 6 swings (rotates) about the rotation support pin 30 in the direction in which the developing roller 11 separates from the photosensitive drum 7. At this time, as shown in fig. 1B and 8B, the contact portion 71a of the detection lever 71 of the remaining toner amount detection unit 70 provided in the main body of the image forming apparatus 100 is brought into contact with the opposite contact portion 37 of the developing unit 6 provided in the main body of the image forming apparatus 100. As described previously, the force received by the contact portion 71a has a value corresponding to the amount of the center of gravity W of the developing unit 6 (including the amount of remaining toner in the toner accommodating chamber 16 b). When the amount of the center of gravity W is larger, the rotational moment due to the developing unit 6 is correspondingly larger.

Then, the detection lever 71 starts rotating about the rotation shaft 71b, stopping rotating at a position where the pressing force applied to the opposed contact portion 37 of the developing unit 6 is balanced with the biasing force P applied by the spring 73. At this time, a gap exists between the restricted portion 60 and the restricting portion 61.

In other words, at this time, a balance is established between the moment generated when the developing unit 6 is rotated about the rotation axis and the moment generated by the pressing of the developing unit 6 by the contact portion 71 a. Therefore, the remaining toner amount detecting unit 70 measures the force applied at this time as a change in the position of the detection lever 71.

As shown in fig. 6A, there is a correlation between the amount of remaining toner in the toner containing chamber 16b and the pressing force applied on the opposed contact portion 37 of the developing unit 6. When the amount of the remaining toner in the toner containing chamber 16b increases, the pressing force exerted on the opposed contact portion 37 of the developing unit 6 also increases, and the biasing force P in balance therewith also increases.

At this time, the control section 120 counts the number of black lines passed on the slit portion 74 attached to the tip of the detection lever 71 according to the output signal from the sensor section 75, and counts the number of pulses as a return value.

As shown in fig. 6B, there is a correlation between the pressing force applied to the opposed contact portion 37 of the developing unit 6 and the number of pulses corresponding to the number of black lines passing on the slit portion 74. Therefore, by using the relationship shown in fig. 6A and 6B, the control portion 120 can calculate the amount of remaining toner in the toner containing chamber 16B. Then, when a predetermined remaining toner amount is detected from the calculated remaining toner amount, the control section 120 performs response processing. Since the predetermined remaining toner amount corresponds to the predetermined number of pulses, the control section 120 may also perform the above-described response process in response to the detection of the predetermined number of pulses without calculating the remaining toner amount.

When the detection of the remaining toner amount is ended, as shown in fig. 1C and 8C, a cam mechanism (not shown) provided in the image forming apparatus 100 main body causes the detection lever 71 to retreat in the direction indicated by the arrow R. This provides a positional relationship: the contact portion 71a of the detection lever 71 is not in contact with the opposing contact portion 37 of the developing unit 6. Since the detection lever 71 is thus retracted to a position where the contact portion 71a of the detection lever 71 does not contact the opposed contact portion 37 of the developing unit 6, the operation of separating the photosensitive drum 7 from the developing roller 11 can be reliably performed in the process cartridge 1. In addition, attachment/detachment of the process cartridge 1 to/from the main body of the image forming apparatus 100 will not be interrupted any more, and damage to the detection lever 71 and the like can be prevented. At this time, the restricted portion 60 and the restricting portion 61 come into contact, and a separation position where the developing roller 11 and the photosensitive drum 7 are separated from each other is determined. When it is assumed that the separation amount (the rotation amount of the developing unit 6 with respect to the photosensitive unit 4) shown in fig. 1B and 8B is the first separation amount and the separation amount in fig. 1C and 8C is the second separation amount, a relationship given by the first separation amount < the second separation amount is established.

Therefore, according to the first embodiment, when the amount of remaining toner in the process cartridge is detected, the pressing by the developing/pressing unit 38 is cancelled, and the pressure due to the weight of the container containing the remaining toner is detected. Therefore, the influence of the pressing based on the spring bias (which is applied to the pressure measuring portion) can be eliminated, and the remaining toner amount can be accurately measured.

Although the first embodiment describes a measuring method in which the slit portion and the sensor each attached to the detection lever of the remaining toner amount detection unit measure the amount of movement of the opposed contact portion of the developing unit in order to measure the amount of remaining toner by way of example, the measure for measuring the amount of movement is not limited to this. In another example of the optical method for measuring the amount of movement, a photosensor or the like may also be used to detect the movement of the developing unit. Alternatively, methods other than optical methods may also be used.

In other words, the remaining toner amount detecting unit may have any configuration as long as the remaining toner amount detecting unit can detect a change determined by the remaining toner amount or a value related to the remaining toner amount. In the configuration having the slit portion and the optical sensor described above, the number of slits in the slit portion detected by the optical sensor may be suitably used as the change, or alternatively, a pressing force based on the number of slits may also be used as the change.

Second embodiment

The form of the second embodiment will now be described with reference to the accompanying drawings.

It should be noted that in the second embodiment, portions different from those in the above-described first embodiment will be described in detail. Materials, shapes, and the like are the same as those in the first embodiment described above unless otherwise specifically stated. These portions are given the same reference numerals, and detailed description thereof is omitted.

Remaining toner amount detecting unit structure

The configuration of the remaining toner amount detecting unit 80 is described below with reference to fig. 7A to 7C. Fig. 7A is a sectional view of a remaining toner amount detecting unit during image formation in a process cartridge according to the second embodiment. Fig. 7B is a sectional view of the remaining toner amount detecting unit during measurement of the remaining toner amount in the process cartridge according to the second embodiment. Fig. 7C is a sectional view of the remaining toner amount detecting unit during development separation in the process cartridge according to the second embodiment.

As shown in fig. 7A to 7C, the remaining toner amount detecting unit 80 is configured to include a load sensor 81, a base 82, and a holder member 83. As an example of the load sensor 81, a load cell (load converter) that detects a change in resistance caused by strain formed under load in the internal structure can be used. The relationship between the resistance value and the load may also be stored in the memory of the control section 120 as a formula or a table.

However, the method of mounting the load sensor is not particularly limited. Not only the load sensor of the gauge type (for example, the semiconductor gauge type or the strain gauge type), but also the load sensor of the electrostatic capacitance type, the load sensor using the diaphragm, and the like may be appropriately selected according to the required performance, use environment, or cost.

Detection of remaining toner amount

The detection of the remaining toner amount will be described below with reference to fig. 2 and fig. 7A to 7C.

As shown in fig. 2, during image formation in the process cartridge 1, each developing unit 6 is pressed by a developing/pressing unit 38 provided in the main body of the image forming apparatus 100 while the developing roller 11 is in contact with the photosensitive drum 7.

In the second embodiment, at this time, as shown in fig. 7A, there is a gap between the load sensor 81 of the remaining toner amount detecting unit 80 provided in the main body of the image forming apparatus 100 and the opposed contact portion 37 of the developing unit 6.

At the same time as the image forming process ends, the pressing by each developing/pressing unit 38 provided in the above-described image forming apparatus 100 main body is released, and the bias of the developing roller 11 against the photosensitive drum 7 is cancelled. Therefore, due to the weight of the developing unit 6, the developing unit 6 swings about the rotational support pin 30 in the direction in which the developing roller 11 separates from the photosensitive drum 7. At this time, as shown in fig. 7B, the load sensor 81 of the remaining toner amount detecting unit 80 provided in the main body of the image forming apparatus 100 is in contact with the opposed contact portion 37 of the developing unit 6.

Then, the load sensor 81 measures a pressing force (load) applied to the opposed contact portions of the developing unit 6.

At this time, the control section 120 calculates the remaining toner amount corresponding to the pressing force. The relationship between the pressing force and the remaining toner amount may also be stored in advance in the memory included in the control section 120 in the form of a formula or a table.

As shown in fig. 7C, when the detection of the remaining toner amount is ended, the load sensor 81 is retracted by a cam mechanism (not shown) included in the main body of the image forming apparatus 100 to a position such that the load sensor 81 and the opposed contact portion 37 of the developing unit 6 do not contact each other. Since the load sensor 81 is retracted to a position where the load sensor 81 and the opposed contact portion 37 of the developing unit 6 do not contact each other, the operation of separating the photosensitive drum 7 and the developing roller 11 from each other can be reliably performed in the process cartridge 1. In addition, it is possible to prevent damage to the load sensor 81 and the like without interrupting the attachment/detachment of the cartridge 1 to/from the image forming apparatus 100 main body.

Therefore, according to the second embodiment, the amount of toner remaining in the process cartridge can also be accurately detected.

Although the second embodiment is described by way of example, the measuring method in which the load sensor of the remaining toner amount detecting unit measures the pressing force exerted on the opposed contact portion of the developing unit and calculates the amount of remaining toner, the measure for measuring the pressing force, are not limited to this. For example, instead of the load sensor, measures of measuring a pull-out force or a frictional force, calculating a pressing force, measuring a remaining toner amount, and the like may also be used. For example, in the configuration according to the second embodiment, the load measured by the load sensor is used as a variation or value corresponding to the amount of remaining toner.

While the present invention has been described with reference to the exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.