JP2021076717A - Displacement reading means and image forming apparatus using the same - Google Patents

Abstract

To provide a more improved developer amount detection configuration in consideration of stable detection of the amount of developer and problems such as an increase in cost and size.SOLUTION: An image forming apparatus of the present invention comprises: photoreceptor units that is coupled with a rotational axis and have image carriers; developer carriers; and pressing members that press pressing target parts of a developing unit corresponding to one side and the other side of the developer carrier when it is divided at the center in the longitudinal direction. When the pressing members press the pressing target parts, the developing unit takes a developing position for supplying a developer from the developer carrier to the image carrier, and when the pressing of the pressing members against the pressing target parts is cancelled, takes a retracted position at which the developer carrier is separated from the image carrier and retracted. When the developing unit is at the retracted position, a change amount detection unit regulates the rotation of the developing unit to receive a force from the developing unit, and outputs the amount of change according to the magnitude of the received force.SELECTED DRAWING: Figure 7

Description

The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile apparatus, and a multifunction device that form an image by an electrophotographic method.

The image forming apparatus forms an image on a recording material by an electrophotographic method, and includes an electrophotographic copying machine and an electrophotographic printer.

In this electrograph, there is also an image forming apparatus that employs a process cartridge method in which a photoconductor and a process means acting on the photoconductor are integrally formed into a cartridge so that the photoconductor and the process means acting on the photoconductor can be attached to and detached from the image forming apparatus main body. According to the process cartridge method, the maintenance of the device can be performed by the operator himself / herself regardless of the service person, so that the operability can be improved. Therefore, the process cartridge method is widely used in electrophotographic image forming apparatus.

Then, in order to detect the amount of the developing agent contained in the process cartridge, it is widely known that the image forming apparatus is provided with the developing agent amount detecting unit. An optical method is widely used for this developer amount detection unit. A light guide is used for the developer accommodating part of the process cartridge, and a light emitting part and a light receiving part are used for the device body corresponding to the light guide when the process cartridge is attached. Are arranged. The light emitted from the light emitting portion is incident from the incident position of the light guide made of a transparent resin member such as acrylic, passes through the developer accommodating portion, and is guided from the emission position outside the developer accommodating portion to the light receiving portion. .. Then, a configuration is used in which the amount of the developer is detected from the ratio of blocking and transmitting the optical path in which the developer is incident in the developer accommodating portion (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2008-145793

The optical developer amount detection method as described in Patent Document 1 has the following concerns. For example, when the light guide is provided at the bottom of the developer accommodating portion, if a certain amount or more of the developer remains, the light receiving element is always shielded from light by the developer, and the amount of the remaining amount of the developer cannot be distinguished. On the other hand, there are countermeasures such as increasing the number of sensors, but there is a concern that the cost will increase and the size will increase.

An object of the present invention is to provide a more developed detection configuration for the amount of a developer in view of the above problems.

In order to solve the above problems, the image forming apparatus of the present invention has a photoconductor unit having an image carrier, a developer carrier and a container capable of accommodating the developer, and rotates with respect to the photoconductor unit. A developing unit rotatably coupled around a shaft, a change amount detecting unit that detects a change amount according to the amount of the developing agent contained in the developing unit, and a longitudinal center of the developing agent carrier. The developing unit includes a pressing member that presses the pressed portion of the developing unit corresponding to one side and the other side when divided by, and the developing unit rotates when the pressing member presses the pressed portion. When the developing position for supplying the developing agent from the developing agent-bearing body to the image-bearing body is taken by rotating around the axis and the pressing of the pressing member on the pressed portion is released, the developing is performed. The agent carrier takes a retracted position where it retracts away from the image carrier, and the change amount detection unit regulates the rotation of the developing unit when the developing unit is in the retracted position. It is characterized in that it receives a force from the above and outputs a change amount according to the magnitude of the received force.

According to the present invention, it is possible to provide a more developed detection configuration for the amount of developer.

It is sectional drawing of the main part of the image forming apparatus main body. It is a main part perspective view which shows the process cartridge and the displacement detection mechanism. It is a main part plan view which shows the pressing means in the contact state and the separated state. It is a perspective view of the main part which shows the stay unit in contact state and the development contact / detachment cam. It is a perspective view of the main part which shows the stay unit in a separated state and the development contact / detachment cam. It is a main part plan view which shows the development contact / detachment cam and development contact / detachment lever which are in contact state and separated state. It is a main part perspective view explaining the displacement detection mechanism which concerns on embodiment. It is sectional drawing of the main part explaining the displacement detection mechanism which concerns on Example. It is sectional drawing of the main part which shows the process cartridge which is in contact state and the displacement detection mechanism. It is sectional drawing of the main part which shows the process cartridge which is separated and the displacement detection mechanism. It is a figure which shows the relationship between the acting force and the displacement amount, and the acting force and the toner amount. It is a main part perspective view explaining the displacement detection mechanism which concerns on embodiment. It is a main part perspective view which shows the process cartridge and the displacement detection mechanism.

[Example 1]
A first embodiment will be described using an electrophotographic and quadruple drum type color image forming apparatus. Here, the image forming apparatus is an apparatus that forms a toner image based on image information input from the outside by a known electrophotographic technique, and transfers and fixes a color image on a medium such as paper. For example, a copier, a laser beam printer, a facsimile machine, and the like are included, but in the present embodiment, a color laser beam printer will be described as an example.

Further, the process cartridge refers to a process means in which at least a developing means and an electrophotographic image carrier (photosensitive drum) are integrally formed into a cartridge and can be attached to and detached from the image forming apparatus main body. Hereinafter, description will be given based on the drawings.

[Outline configuration of image forming apparatus]
FIG. 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus main body when the image forming apparatus is viewed from the front side. FIG. 1 is a tandem color image forming apparatus in which four process cartridges 7a, 7b, 7c, and 7d are arranged in a straight line.

(1) Toner image forming process The toner image is formed by a developing unit 4 having a photosensitive drum 1, a charging means 2, an exposure means 3, and a developing roller as a developing means. The image forming apparatus 100 includes four photosensitive drums 1a, 1b, 1c, and 1d. Around each photosensitive drum 1, toner is attached to an electrostatic latent image by charging means 2 (2a, 2b, 2c, 2d) that uniformly charges the surface of the photosensitive drum 1 in order according to the rotation direction. The developing unit 4 (4a, 4b, 4c, 4d) that is visualized as is disposed. Further, there are transfer means 12a, 12b, 12c, 12d for transferring the toner image on the photosensitive drum 1 to the intermediate transfer belt 12e. Further, cleaning means 8 (8a, 8b, 8c, 8d) for removing the transfer residual toner remaining on the surface of the photosensitive drum 1 after transfer is provided.

Photosensitive drum 1 (1a, 1b, 1c, 1d), charging means 2 (2a, 2b, 2c, 2d), developing unit 4 (4a, 4b, 4c, 4d), and cleaning means 8 (8a, 8b, 8c, 8d) are integrated into cartridges to form process cartridges 7 (7a, 7b, 7c, 7d). Each of the process cartridges 7 is detachably provided to the image forming apparatus 100, and in this embodiment, the process cartridge 7 is detachably attached to the front side of the image forming apparatus 100. These four process cartridges 7a, 7b, 7c, and 7d have the same structure, but different color images are formed by the toners of yellow (Y), magenta (M), cyan (C), and black (Bk). Is different.

The photosensitive drum 1 (1a, 1b, 1c, 1d) is formed by applying an organic optical conductor layer (OPC) to the outer peripheral surface of an aluminum cylinder, and both ends thereof can be rotated by bearings or the like. It is supported. By transmitting a driving force from a drive motor (not shown) to one end of the photosensitive drum 1 (1a, 1b, 1c, 1d), the drum 1 (1a, 1b, 1c, 1d) is rotationally driven in the clockwise direction shown in FIG.

The charging means 2 (2a, 2b, 2c, 2d) is a conductive roller formed in a roller shape, and the roller is brought into contact with the surface of the photosensitive drum 1 (1a, 1b, 1c, 1d) and the charging voltage is applied. It is applied to uniformly charge the surface of the photosensitive drum 1 (1a, 1b, 1c, 1d).

The exposure means 3 is arranged vertically below the process cartridge 7 (7a, 7b, 7c, 7d), and exposes the photosensitive drum 1 (1a, 1b, 1c, 1d) based on the image signal. More specifically, each photosensitive drum is provided with a laser diode for irradiating a laser, and an electrostatic latent image is formed on the photosensitive drum 1 by laser irradiation based on image information. The means for emitting an electrostatic latent image on the surface of the photosensitive drum 1 is not limited to the laser diode, and for example, an LED array extending in the longitudinal direction of the photosensitive drum 1 may be provided corresponding to each photosensitive drum.

Toner (developer) can be stored The toner containers 25a, 25b, 25c, and 25d contain toners of each color of yellow (Y), magenta (M), cyan (C), and black (Bk), respectively.

The developing rollers 24 (24a, 24b, 24c, 24d), which are also the developer carriers, are arranged adjacent to the surface of the photosensitive drum 1 (1a, 1b, 1c, 1d), which is the image carrier. These developing rollers transition to a contact state and a separation state with respect to the corresponding photosensitive drums 1 (1a, 1b, 1c, 1d) by a development contact / detachment mechanism described later. In the abutting state, the toner is rotationally driven by a driving unit (not shown), and by applying a voltage, toner is applied to the electrostatic latent image portion formed on the surface of the photosensitive drum 1 (1a, 1b, 1c, 1d). To develop.

With the above configuration, toner images of Y, M, C, and Bk are formed on the surfaces of the photosensitive drums 1a, 1b, 1c, and 1d. The toner images formed on the surfaces of the photosensitive drums 1a, 1b, 1c, and 1d are sequentially transferred to the surface of the intermediate transfer belt 12e (primary transfer process). After that, the residual toner on the surface of the photosensitive drum 1 (1a, 1b, 1c, 1d) is removed by the cleaning means 8 (8a, 8b, 8c, 8d), and the residual toner in the cleaning unit 5 (5a, 5b, 5c, 5d) is removed. The transfer residue is collected in the toner container 26 (26a, 26b, 26c, 26d).

(2) Transfer process and fixing process to the sheet material The transfer of the toner image to the sheet material S is performed by the sheet material S being conveyed to the secondary transfer unit 15 by the paper feeding device 13 and performed by the secondary transfer unit 15. .. The intermediate transfer unit 12 carries the toner image formed by the primary transfer process and conveys the toner image to the secondary transfer unit 15. The fixing device 14 is located on the downstream side of the secondary transfer unit 15 in the sheet material S transport direction, and fixes the toner image transferred on the sheet material S.

First, the configurations of the paper feed device 13, the intermediate transfer unit 12, and the fixing device 14 will be described. The paper feed device 13 is mainly composed of a paper feed cassette 11 for storing the sheet material S, a paper feed roller 9, a separation means 23, and a resist roller pair 17 for sandwiching and transporting the sheet material S. The paper cassette 11 can be pulled out from the image forming apparatus 100, and the user sets the sheet material S in the paper feed cassette 11 after pulling out the paper feed cassette 11 from the image forming apparatus 100, and attaches the sheet material S to the image forming apparatus 100. By doing so, the sheet material S can be replenished.

The intermediate transfer unit 12 is mainly composed of an intermediate transfer belt (intermediate transfer material) 12e, a drive roller 12f, a driven roller 12g, primary transfer rollers 12a, 12b, 12c, 12d which are primary transfer means, and a cleaning device 22. .. The intermediate transfer belt 12e is an endless cylindrical belt, which is stretched on a driving roller 12f and a driven roller 12g. The driven roller 12g is urged in the direction A indicated by the arrow in FIG. 1 by an urging means (not shown) to apply a predetermined tension to the intermediate transfer belt 12e. When the drive roller 12f is rotationally driven by a motor (not shown) or the like, the intermediate transfer belt 12e rotates at a predetermined speed in the B direction shown by the arrow in FIG. The primary transfer rollers 12a, 12b, 12c, 12d are arranged inside the intermediate transfer belt 12e facing the photosensitive drums 1a, 1b, 1c, and 1d, and the primary transfer rollers 12a, 12b, 12c, and 12d are arranged. By applying a voltage to, the toner images formed on the surfaces of the photosensitive drums 1a, 1b, 1c, and 1d are primarily transferred onto the intermediate transfer belt 12e.

The fixing device 14 is mainly composed of a fixing film 14a, a pressure roller 14b, a heating body 14c, and a paper ejection roller pair 20. The fixing film 14a is an endless cylindrical belt, and the outer peripheral surface of the fixing film 14a is arranged on the toner image surface side on the sheet material S. The heating body 14c is arranged inside the fixing film 14a, and the pressure roller 14b is in pressure contact with the fixing film 14a. The pressure roller 14b is rotationally driven by a driving means (not shown), the fixing film 14a is rotated accordingly, and the fixing film 14a is heated by the heating body 14c.

In the transport direction of the sheet material S, a paper ejection roller pair 20 and a paper ejection tray 21 are arranged on the downstream side of the fixing film 14a. The output tray 21 has an inclined surface 21a that is inclined with respect to the horizontal direction. The inclined surface 21a is inclined in the direction in which the paper ejection roller vs. 20 side is lowered.

Next, the operations of the paper feeding device 13, the intermediate transfer unit 12, and the fixing device 14 will be described. The paper feed roller 9 is in pressure contact with the sheet material S stored in the paper feed cassette 11, and since it rotates at a predetermined control timing, the sheet material S is sent out, and the sheet materials S are separated one by one by the separating means 23. Separated and fed. After that, the sheet material S is conveyed to the secondary transfer unit 15 by the resist roller pair 17. Further, the four-color toner images are overlaid on the intermediate transfer belt 12e, transferred and supported, and conveyed to the secondary transfer unit 15.

In the secondary transfer unit 15, a bias voltage is applied to the secondary transfer means 16 to transfer the toner image on the intermediate transfer belt 12e onto the transferred sheet material S. After the secondary transfer, the toner remaining on the intermediate transfer belt 12e is removed by the cleaning device 22 and conveyed to a toner recovery container (not shown) arranged in the image forming device 100. The sheet material S conveyed from the secondary transfer unit 15 is sandwiched and conveyed between the fixing film 14a and the pressure roller 14b, and the toner image is heat-fixed on the sheet material S. The sheet material S on which the toner image is fixed is then sandwiched and conveyed by the paper ejection rollers vs. 20 and discharged to the paper ejection tray 21. Even when a plurality of sheet materials S are loaded on the paper ejection tray 21, the subsequent sheet materials S are discharged. Since the sheet material S loaded on the inclined surface 21a provided on the output tray 21 is also inclined, the sheet S is aligned without pushing out the sheet material S on which the discharged sheet material S is loaded. It is loaded on the output tray 21 in a maintained state.

[Outline configuration of controller]
The controller 10 has a CPU 101, a memory 102, and an input / output interface 103 as a main configuration. The CPU 101 executes various programs stored in the memory and controls the image forming operation. The memory 102 is a general term for a volatile memory and a non-volatile memory. For example, a signal indicating or related to the displacement detected by the displacement detection mechanism 50 described later is input via the input / output interface 103, referred to by the CPU 101, and used for various arithmetic processes.

[Outline configuration of cartridge]
FIG. 2 is a perspective view showing the appearance of the process cartridge 7 and the displacement detection mechanism 50 described later. The process cartridge 7 is an assembly whose longitudinal direction is the axial direction (C direction in FIG. 3) of the photosensitive drum 1. The process cartridge 7 is mainly composed of a developing unit 4 and a cleaning unit 5. Of these, the former developing unit 4 has a developing roller 24 and a toner container 25. The latter cleaner unit 5 (photoreceptor unit) has a photosensitive drum 1, a charging means 2, a cleaning means 8, and a transfer residual toner container 26.

The developing roller 24 is rotatably directly or indirectly supported by the toner container 25. Further, the toner container 25 is provided with a pressed portion 28 to be pressed by the pressing members 30 (31b, 32b) (see FIG. 9) arranged in the image forming apparatus main body described later. The developing unit 4 is provided with a toner container 25, and the toner containers 25a, 25b, 25c, and 25d of the process cartridges 7a, 7b, 7c, and 7d each contain toner of a corresponding color.

The photosensitive drum 1 is rotatably supported by the transfer residual toner container 26. As shown in FIGS. 9 and 10, cleaning means 8 and charging means 2 are arranged around the photosensitive drum 1 from the upstream side in the rotation direction of the photosensitive drum 1 and come into contact with the photosensitive drum 1. There is.

As shown in FIG. 2, the developing unit 4 is swingably supported by the cleaning unit 5 around the developing rocking center 27 (rotating shaft 27). For example, a boss protruding from the side surface of the toner container 25 rotatably fits into the hole of the transfer residual toner container 26 to form a rotation shaft portion. In a state where no external force is applied to the process cartridge 7, the developing unit 4 is coupled to a cleaning unit 5 as a photoconductor unit and a rotating shaft (rotating shaft) having a developing swing center 27. Then, the developing unit 4 rotates around the developing rocking center 27 in the D direction in FIG. 2 due to the weight of the developing unit 4. Further, a part of the displacement detection mechanism 50 (change amount detection unit) is arranged outside the developing unit 4 in the longitudinal direction of the developing roller 24 at the same position in the gravity direction. As a result, the displacement detection mechanism 50 does not interfere with the developing unit 4 when the developing unit 4 takes a separation operation.

Next, the support configuration when the process cartridge 7 is mounted on the image forming apparatus will be described. As shown in FIGS. 9 and 10, when the process cartridge 7 is attached to the image forming apparatus, the support means 37 provided in the image forming apparatus and the transfer residual toner container 26 of the cleaning unit 5 are positioned. That is, the support means 37 is fixed and positioned on the main body of the image forming apparatus. When the pressed portion 28 of the developing unit 4 is pressed by the pressing member 30 by the developing contact / detaching mechanism described later with the process cartridge 7 mounted on the image forming apparatus, the developing unit 4 moves the developing swing center 27. Rotate to the center. By this rotation, the developing roller 24 comes into contact with the photosensitive drum 1 at a desired contact pressure.

[Abutment separation configuration of developing means]
FIG. 3A is a plan view showing a pressing mechanism 29 and a stay 36a in a state where the developing roller is in a contact position, and FIG. 3B is a plan view showing a pressing mechanism 29 and a stay 36a in a state where the developing roller is in a separated position. It is a plan view which shows. Further, FIG. 4 is a perspective view showing the pressing mechanism 29 and the stay 36a in a state where the developing roller is in the contact position, and FIG. 5 is a perspective view showing the pressing mechanism 29 and the stay 36a in the state where the developing roller is in the separated position. It is a figure. The contact state corresponds to the development position where the development roller 24 toner is supplied to the photosensitive drum 1. This contact state also corresponds to the contact position.

As shown in FIG. 3A, the pressing mechanism 29 is supported by the stay 36a. Further, the pressing mechanism 29 is a pressing portion that can be moved between a pressing position that presses the pressed portion 28 of the toner container 25a to bring the developing roller 24a into contact with the photosensitive drum 1a and a retracting position that is retracted from the pressing position. It has 30. Further, the pressing mechanism 29 is interlocked by connecting the urging member 80 that urges the pressing portion 30, the contact / detachment lever 34 that is rotatably supported by the stay 36a, and the contact / detachment lever 34 and the pressing portion 30. An interlocking member 33 (slide member 33) to be operated is provided.

The first pressing portion 30 is rotatably supported with respect to the stay 36a between the pressing position and the retracting position about the central axes 31a and 32a arranged with a gap in the width direction C. It includes a pressing member 31 and a second pressing member 32. The first and second pressing members 31 and 32 are arranged at different positions in the width direction C. As shown, the first pressing member 31 and the second pressing member 32 are arranged on one side (front side) and the other side (back side) with respect to the longitudinal direction of the developing roller 4 with the center position in the longitudinal direction interposed therebetween. Has been done. Specifically, the first pressing member 31 is arranged on the first end 41 side (front side), which is one end of the stay 36a in the width direction C, and the second pressing member 32 is arranged in the width direction C of the stay 36a. It is arranged on the second end 42 side (back side), which is the other end of the above. Further, each of the first and second pressing members 31 and 32 includes contact portions 31b and 32b capable of contacting the pressed portion 28 of the toner container 25a. It is desirable that the first pressing member 31 and the second pressing member 32 do not protrude from the stay 36a in the D direction (horizontal direction in FIG. 1) of FIG. 3A within the rotation range thereof. The urging member 80 is provided for each of the first pressing member 31 and the second pressing member 32, one end of which is supported by the urging member holding portions 36e and 36f of the stay, and the other end of which is the first pressing member. It is supported by 31 and the second pressing member 32. The urging member 80 urges the first pressing member 31 and the second pressing member 32 from the retracted position to the pressing position so as to rotate in the J1 direction of FIG. 3A. The urging member may be provided on one of the first pressing member and the second pressing member, and the interlocking member 33 may be directly provided instead of the first pressing member and the second pressing member. It may be provided to be urged.

The contact / detachment lever 34 is slidably supported with respect to the stay 36a about the rotation shaft 34a, and is interlocked with the rotation shaft 34b arranged radially apart from the rotation shaft 34a. It is rotatably supported by the member 33. FIGS. 4 to 6 described later show a state in which the interlocking member 33 is supported by the interlocking member 33 with the rotation shaft 34b as the center. The rotation shaft 34a of the contact / release lever 34 is arranged on the back surface side (end side) of the stay 36a with respect to the central shafts 31a and 32a of the first pressing member 31 and the second pressing member 32. Further, the contact / release lever 34 is also arranged on the back surface side (end side) of the stay 36a with respect to the first pressing member 31 and the second pressing member 32.

As shown in FIG. 4, the interlocking member 33 is formed along the width direction C (see FIG. 3) and has a slide groove 33a into which a guide protrusion 39 provided on the stay 36a is inserted. , Is movably supported along the width direction C with respect to the stay 36a. The movable range of the stay of the interlocking member 33 in the width direction C may be regulated by both ends of the guide protrusion 39 and the slide groove 33a in the width direction C. Further, the interlocking member 33 has contact surfaces 33b and 33c capable of contacting the first pressing member 31 and the second pressing member 32. As a result, the interlocking member 33 is such that when the interlocking member 33 (rotating shaft 34b) moves, the contact / release lever 34, the first pressing member 31 and the second pressing member 32 are interlocked to rotate. It is connected to the 1 pressing member 31 and the 2nd pressing member 32.

As described above, the stays 36a to 36d independently support the pressing mechanisms 29 provided corresponding to each of the stays 36a to 36d. Further, the stays 36a to 36d and the pressing mechanism 29 provided corresponding to each constitute the stay units 40a, 40b, 40c, and 40d, which are independent of each other.

[Configuration to operate the pressing mechanism]
FIG. 6A is a plan view showing the stay unit 40a with the developing roller in the contact position and the contact / detachment cam 35, and FIG. 6B shows the stay unit 40a with the developing roller in the separated position. It is a top view which shows the contact / detachment cam 35. As shown in FIGS. 6A and 6B, each pressing mechanism 29 is provided with a contact / detachment cam 35 that is rotatably supported with respect to the housing of the image forming apparatus.

The contact / detachment cam 35 is arranged on the rear side plate side, and is rotated by a drive device (not shown). For example, the drive device includes a stepping motor, a motor control unit that controls the stepping motor, and the like. The contact / detachment cams 35 may be driven by the same drive source, or may be driven by individually provided drive sources.

Further, the contact / detachment cam 35 can come into contact with the contact surface 34c of the contact / detachment lever 34, and the distance from the rotation center of the contact / detachment cam 35 differs depending on the rotation position (rotation phase) of the contact / detachment cam 35. The rotation position of the contact / detachment lever 34 is changed depending on the rotation position. It is desirable that the cam surface 35a of the contact / disengagement cam 35 can be separated from the contact / disengagement lever 34 at any of the rotation positions.

When the rotation position of the contact / detachment cam 35 is the first cam position shown in FIGS. 3 (a), 4 and 6 (a), the pressing mechanism 29 has the first pressing member 31 and the second pressing member 32. It is in a pressing state located at the pressing position due to the urging force of the urging member 80. When the pressing mechanism 29 is in the pressing state, the toner container corresponding to the pressing mechanism 29 is in contact with the contact portion 31b of the first pressing member 31 and the contact portion 32b of the second pressing member 32 and the pressed portion 28. Therefore, the rotation positions of the first pressing member 31 and the second pressing member 32 are regulated. As a result, the developing roller corresponding to the pressing mechanism 29 is held at a contact position where the developing roller is pressed so as to come into contact with the photosensitive drum at a predetermined contact pressure by the urging member 80 via the pressing portion 30 and the toner container.

When the contact / disengagement cam 35 rotates by a predetermined amount in the L1 direction of FIG. 4 from the first cam position shown in FIGS. 4 and 6 (a), the cam surface 35a presses the contact / disengagement lever 34, and FIG. 6 (a) shows. Rotating in the N1 direction, the contact / detachment cam 35 becomes the second cam position shown in FIGS. 5 and 6 (b). At this time, the interlocking member 33 moves in the C2 direction (front side) in FIG. 6A by the rotation of the contact / detachment cam 35. The first pressing member 31 (contact portion 31b) and the second pressing member 32 (contact portion 32b) resist the urging force of the urging member 80 by the movement of the interlocking member 33, and J2 in FIG. 3 (b). It rotates in the direction and becomes the retracted position. In this state, the pressing mechanism 29 is in a retracted state with respect to the pressed portion 28 as shown in FIGS. 3 (b), 5 and 6 (b).

When the pressing mechanism 29 is in the retracted state, the rotation positions of the first pressing member 31 and the second pressing member 32 are regulated by the contact surfaces 33b and 33c of the interlocking member 33. Further, when the first pressing member 31 and the second pressing member 32 rotate to the retracted position, the urging force of the urging member 80 is released from the toner container corresponding to the pressing mechanism 29, and D in FIG. 2 due to its own weight. Rotate in the direction. As a result, the developing roller corresponding to the pressing mechanism 29 moves to the separated position.

When the contact / detachment cam 35 further rotates a predetermined amount in the L1 direction of FIG. 5 from the second rotation position shown in FIGS. 5 and 6 (b), the contact / detachment cam 35 is brought into contact with the urging force of the urging member 80 via the interlocking member 33. The release lever 34 rotates in the N2 direction in FIG. 6B while contacting the cam surface 35a. As a result, the contact / detachment cam 35 becomes the first rotation position shown in FIGS. 4 and 6 (a). At this time, the first pressing member 31 and the second pressing member 32 are rotated in the J1 direction of FIG. 3A by the urging force of the urging member 80 to reach the pressing position.

Further, the interlocking member 33 moves in the C1 direction (back side) of FIG. 6B due to the rotation of the first pressing member 31 and the second pressing member 32 in the J1 direction, and the pressing mechanism 29 is in the pressing state (the pressing state (back side)). FIG. 3A). The contact / detachment cam 35 rotates in a direction opposite to the direction of rotation from the first cam position to the second cam position (L1 direction in FIG. 4) from the second rotation position to the first rotation position. It may be controlled to rotate. The same effect can be obtained by this as well. If the cam drive device supports reverse rotation, reverse rotation may be adopted. In this way, the contact / detachment cam 35 is rotated by the drive device (not shown), so that the pressing mechanism 29 is activated and the charging roller is brought into contact with the photosensitive drum.

In the example shown in FIG. 4, the contact portions 31b and 32b are shown as separate members. However, it is not limited to this form. With respect to the longitudinal direction of the developing roller 4, if pressing is performed on one side (front side) and the other side (back side) of the center position in the longitudinal direction, there is only one member that abuts the pressed portion 28. It may be composed of. For example, it is movably connected to the first pressing member 31 (contact portion 31b) and the second pressing member 32 (contact portion 32b) described with reference to FIG. The pressing member may be composed of one member that can take the contact position and the retracted position in conjunction with each other.

[Displacement detection mechanism configuration]
FIG. 7 is a perspective view showing a main part of the displacement detection mechanism 50, which is an example of the change amount detection unit. 8A and 8B are cross-sectional views showing a main part of the displacement detection mechanism 50, FIG. 8A is a contact state (state shown in FIG. 4), and FIG. 8B is a separated state (shown in FIG. 5). It is sectional drawing of the displacement detection mechanism 50 when it is in a state). FIG. 2 is a perspective view showing the positional relationship between the displacement detection mechanism 50 and the process cartridge 7, and FIGS. 9 and 10 are cross-sectional views showing the main parts of the displacement detection mechanism 50 and the process cartridge 7.

First, the configuration of the displacement detection mechanism 50 will be described with reference to FIG. 7. The displacement detection mechanism 50 is mainly composed of a support member 51, a rotating shaft 52 integrally formed with the support member, a swing member 53, a contact portion 54, an elastic member 55, and a displacement reading portion 56. The swing member 53 is engaged with the shaft portion of the rotary shaft 52, and is supported by the shaft portion so as to be swingable around the rotary shaft 52.

As shown in FIGS. 2 and 10, the contact portion 54 is provided at a position where the developing roller 24 comes into contact with the toner container 25 when the developing roller 24 is separated from the photosensitive drum 1. As shown in FIG. 8, the elastic member 55 urges the rocking member 53 toward the developing unit side (the direction in which the developing roller 24 abuts on the photosensitive drum 1 side) when the contact portion 54 touches the toner container 25. It is provided. In this embodiment, a coil spring is used for the elastic member 55. The characteristics (spring constant) of the coil spring are set based on the acting force (load) generated according to the amount of toner in the toner container 25, which will be described later, and the assumed maximum displacement amount of the spring.

The displacement detection mechanism 50 repeats (i) an optical sensor including a light emitting unit that emits light and a light receiving unit that receives light, and (ii) a transmitting unit that transmits light from the light emitting unit and a light shielding unit that blocks light. It is composed of an arranged read unit. More specifically, the displacement reading unit 56 is arranged at a position away from the rotation shaft 52 of the swing member 53, and can read the displacement of the read portion 57 of the swing member 53. In this embodiment, an encoder is used for the displacement reading unit 56, and an optical sensor having a light emitting element and a light receiving element that receives light emitted by the light emitting element is arranged. The read unit 57 is provided with a transmissive unit that transmits light emitted by the light emitting element and a light-shielding unit that blocks light at a predetermined cycle. The portion indicated by the black line in the figure corresponds to the light-shielding portion, and the transparent portion and the light-shielding portion are repeatedly arranged by printing the black line on the transparent sheet. Then, when the rocking member 53 swings, the amount of change in the mechanical position of the rocking member 53 is measured by inputting and counting the number of times of transmission and / or shading by the light-shielding portion (black line) into the CPU 101. .. The measurement of the displacement amount here means to acquire the count value of the number of times of transmission / shading, and the number of times of repeating the light reception by the light receiving element and the light shading by the light shielding portion is acquired as the count value by the CPU 101. To. Further, the same effect can be obtained by counting the number of times of shading or only the number of times of transmission by the CPU 101, instead of the number of repetitions.

A specific transmission and / or shading count corresponds to the amount of toner remaining to be detected, and the CPU 101 counts the specific transmission and / or shading count to obtain a predetermined toner remaining amount. The control unit 120 executes the corresponding processing when is detected. When a predetermined remaining amount of toner is detected, the corresponding processing includes, for example, notification of the remaining amount of toner, notification of low amount of toner remaining, notification of toner empty, notification of cartridge replacement, toner replenishment, and the like. Can be done. Further, regarding the detection of the remaining amount of toner in the CPU 101, the amount of toner may be obtained from the table in FIG. 11B, and the predetermined amount of remaining toner may be detected based on the amount of toner, but the present invention is not limited to this. The number of times of transmission and / or shading, the acting force, and the amount of toner basically have a one-to-one correspondence, and it is not always necessary for the CPU 101 to convert the number of times of transmission and / or shading into the amount of toner. The CPU 101 can obtain the same action and effect even if a predetermined process programmed in advance corresponding to the count value is executed with a count of the number of times of transmission and / or shading with a specific number of times of transmission and / or shading.

In addition, in FIG. 7, both the light emitting part and the light receiving part of the displacement reading part 56 were fixed, the position of the read part 57 was moved, and the relative motion between the displacement reading part 56 and the read part 57 was generated. .. However, it is not limited to this. For example, the read portion 57 may be fixed on the pedestal in a posture as shown in FIG. 7, and a displacement reading portion 56 may be provided at the end of the swing member 53 instead of the read portion 57. In this case, the reading portion 56 has a U-shape having an opening that opens downward so as to sandwich the read portion 57 in a direction perpendicular to the swing direction of the swing member 53. By doing so, the relative motion between the displacement reading unit 56 and the read unit 57 can be generated, and the number of times of transmission and / or shading can be similarly counted.

Next, the operation of the displacement detection mechanism 50 will be described with reference to FIGS. 9 and 10. After the image formation process is completed, the developing unit 4 of the process cartridge 7 mounted on the main body of the apparatus rotates counterclockwise in FIG. 10 due to the positional relationship between the position of the center of gravity of the developing unit 4 and the center of developing swing 27, and develops shaking. The developing unit 4 rotates around the moving center 27 and becomes separated. At this time, it is assumed that the pressing member 30 (31b, 32b) has not pressed the pressed portion 28. As shown in FIG. 8, the toner container 25 and the contact portion 54 are in contact with each other in a separated state. A moment acts on the toner container 25 around the development swing center 27 according to the amount of toner in the toner container 25, and exerts an acting force on the contact portion 54. On the other hand, as shown in FIG. 8B, since the swing member 53 is urged by the elastic member 55, a moment acts in the counterclockwise direction around the rotation shaft 52, and the contact portion 54 is moved to the toner container 25. It exerts an action force. Therefore, the swing member 53 stops at a position that is balanced with the acting force according to the amount of toner in the toner container 25. At this time, the rotating operation of the stirring member (developing agent transporting member) arranged in the toner container 25 to stir the toner by rotating is stopped. Therefore, the amount of the developer can be detected without being affected by the developer whose state is different depending on the rotation operation. Further, when the developing unit 4 is in the retracted position, the displacement detection mechanism 50 can detect the movement of the developing unit 4 which changes depending on the amount of the remaining amount of toner in the developer accommodating portion by performing a detection operation. The remaining amount of toner can be detected in response to a large amount. In order to detect various toner remaining amounts with a conventional optical sensor, there is a cost advantage as compared with the case where a plurality of sensors are used. In addition, the effect of space reduction can be obtained as compared with the case where a plurality of sensors are provided.

When the process cartridge 7 transitions from the contact state shown in FIG. 4 to the separated state shown in FIG. 5, the rocking member 53 swings and stops at a position commensurate with the acting force according to the amount of toner in the toner container 25. .. At this time, the read unit 57 also moves to a position in the toner container 25 according to the amount of toner. The CPU 101 determines how much the read unit 57 has moved by reading how many cycles the light-shielding and / or transmission by the optical sensor 56 is repeated.

The relationship between the acting force acting on the contact portion 54 and the displacement of the read portion 57 will be described with reference to FIGS. 11 (a) and 11 (b). 11 (a) and 11 (b) schematically show a table stored in the memory 102 of the controller 10. Further, as described above, the displacement amount corresponds to the count value of the number of times of transmission and / or shading counted by the CPU 101.

When the acting force α1 acts on the contact portion 54, the elastic member 55 is elastically deformed according to the acting force α1, and the read portion 57 moves by a displacement amount of δ1. Moving the displacement amount δ1 means that the CPU 101 counts the number of times of transmission and / or shading corresponding to the displacement amount δ1. Further, when the acting force α2 acts on the contact portion 54, the elastic member 55 is elastically deformed according to the acting force α2, and the read portion 57 moves by the displacement amount δ2. If the acting force α1 <acting force α2, the displacement amount δ1 <displacement amount δ2.

As shown in FIG. 11A, the relationship between the acting force and the amount of displacement is a substantially linear relationship. Further, the relationship between the amount of toner in the toner container 25 and the acting force is also a substantially linear relationship as shown in FIG. 11 (b). Therefore, by measuring the acting force in the amount of toner in the toner container 25 to be detected in advance and storing the relationship (table) in the memory 102 so that the CPU 101 can refer to it in advance, the CPU 101 can refer to the detected displacement amount in the toner container. The amount of toner in 25 can be determined. Further, even if the relationship between the amount of toner and the acting force is not linear, if the home position or address of the read unit 57 can be identified, the relationship may be held in the memory 102 as a table in advance. The CPU 101 identifies the displacement amount and the home position or address, and inputs the displacement amount to the table, so that the acting force can be predicted from the displacement amount.

The acting force at the minimum toner amount β1 to be detected is defined as the acting force α1, and the acting force at the maximum toner amount β2 to be detected is defined as the acting force α2. If the detection result by the displacement reading unit 56 is the displacement amount δ1, the amount of toner in the toner container 25 is the toner amount β1, and if the detection result by the displacement reading unit 56 is the displacement amount δ2, the toner amount is the toner. The amount is β2. Even with the toner amount from the toner amount β1 to the toner amount β2, as described above, the relationship between the acting force and the displacement amount and the relationship between the toner amount and the acting force are generally linear, so the displacement amount from the displacement amount δ1. By reading the amount of displacement of δ2, the amount of toner in the toner container 25 can be detected.

For example, if the acting force when the toner amount is β3 is α3 and the displacement amount is δ3 at that time, the toner amount when the displacement detection mechanism 50 reads the displacement amount δ3 is β3 (see FIG. 11).

Here, the load to be supported by the coil spring used as the elastic member 55 may be set according to the amount of toner to be detected. In this embodiment, the displacement detection mechanism 50 can detect the amount of toner to be detected by using a coil spring having a spring constant that is the acting force from the acting force α1 to the acting force α2 in the displacement amount from the displacement amount δ1 to the displacement amount δ2. Become.

The configuration of detecting the toner amount by reading the displacement amount from the contact state to the separated state has been described. However, in the contact state, as shown in FIG. 4, the toner container 25 and the contact portion 54 are in contact with each other. It is desirable to be far away. In this embodiment, the pressing member 30 generates a contact pressure between the photosensitive drum 1 in the contact state and the developing roller 24. When the toner container 25 receives an acting force from the contact portion 54 of the displacement detection mechanism 50 in the contact state, it leads to a factor that the contact pressure fluctuates by that amount. Therefore, in the contact state, the contact portion 54 comes into contact with the developing unit 4. If it is not provided, the contact pressure between the photosensitive drum 1 and the developing roller 24 will be stabilized.

As described above, the displacement detection mechanism 50 provided on the apparatus main body side detects the displacement of the developing unit 4 in the separated state of the cartridge, and determines the amount of toner in the toner container 25 according to the magnitude of the displacement amount. Can be done. Therefore, it is possible to realize a detection configuration for the amount of the developer corresponding to the speeding up of the image forming apparatus. Furthermore, it is possible to realize a configuration in which a stable amount of developer can be detected even when the amount of developer is large.

[Example 2]
In the second embodiment, a configuration of a displacement detection mechanism that detects the amount of toner in the toner container with a configuration different from that of the first embodiment will be described. The parts different from those of the first embodiment will be mainly described, and the common parts are the same as those of the first embodiment, so the description thereof will be omitted.

Hereinafter, the second embodiment will be described with reference to the drawings. FIG. 12 is a perspective view showing a main part of the displacement detection mechanism 60, which is another example of the change amount detection unit. FIG. 13 is a perspective view showing the positional relationship between the displacement detection mechanism 60 and the process cartridge 7.

First, the configuration and function of the displacement detection mechanism 60 will be described with reference to FIGS. 12 and 13. The displacement detection mechanism 60 is mainly composed of a support member 61, a swing member 63, a contact portion 64, an elastic member 65, and a resistance portion 66. The swing member 63 is swingably supported about the rotation shaft 62 with respect to the support member 61 via the resistance portion 66. As shown in FIG. 13, the contact portion 64 is provided at a position where it comes into contact with the toner container 25. The elastic member 65 is provided so as to urge the swing member 63 in the direction in which the contact portion 64 comes into contact with the toner container 25.

In FIG. 12A, the resistance portion 66 has a cylindrical shape, a resistor is attached to the side surface of the cylinder, and a movable contact that moves on the resistor formed on the circumference thereof is formed. It is provided at a portion of the rocking member 63 that covers the resistance portion 66. A variable resistor is formed by a portion that covers the resistance portion 66 and the resistance portion 66 of the rocking member 63. FIG. 12B shows an equivalent circuit of a variable resistor. If the voltage between the terminals 1 and 2 is detected with respect to the input voltage between the terminals 1 and 3, the CPU 101 can obtain the detection result of the variable resistance value by the movable contact. When the swing member 63 swings in this way, the position of the movable contact with respect to the resistor moves, and the resistance value detected from the movable contact changes. When the CPU 101 detects this variable resistance value, the CPU 101 can grasp the amount of rotation of the rocking member 63, and the amount of rotation (resistance value) is the displacement of the contact portion 64 arranged on the rocking member 63. The amount of residual toner can be calculated by regarding it as the amount. In FIG. 11 described above, the correspondence between the displacement amount and the action amount was stored in the memory as a table, but here, instead of the displacement amount, the relationship between the resistance value and the action amount is stored in the memory 102 as a table. Then, the CPU 101 may refer to it as appropriate.

Next, the operation of the displacement detection mechanism 60 will be described with reference to FIGS. 12 and 13. After the completion of the image forming process, the developing unit 4 of the process cartridge 7 mounted on the main body of the apparatus rotates in the D direction in FIG. 13 due to the positional relationship between the position of the center of gravity of the developing unit 4 and the center of development swing 27, and becomes separated. .. In the separated state, the toner container 25 and the contact portion 64 are in contact with each other. A moment acts on the toner container 25 around the development swing center 27 according to the amount of toner in the toner container 25, and exerts an acting force on the contact portion 64. On the other hand, since the swing member 63 is urged by the elastic member 65, a moment acts in the counterclockwise direction around the rotating shaft 62, and the contact portion 64 exerts an acting force on the toner container 25. Therefore, the swing member 63 stops at a position balanced with the acting force according to the amount of toner in the toner container 25.

When the process cartridge 7 transitions from the contact state to the separated state, the rocking member 63 swings and stops at a position commensurate with the acting force according to the amount of toner in the toner container 25. At this time, since the resistance value also changes, it is determined how much the contact portion 64 is displaced by reading the amount of change in the resistance value.

As described above, the displacement detection mechanism 60 can detect the displacement of the developing unit 4 in the separated state of the cartridges, and can determine the amount of toner in the toner container 25 according to the magnitude of the displacement amount. Therefore, it is possible to realize a detection configuration for the amount of the developer corresponding to the speeding up of the image forming apparatus. Furthermore, it is possible to realize a configuration in which a stable amount of developer can be detected even when the amount of developer is large.

1 Photosensitive drum 4 Development unit 5 Cleaning unit 7 Process cartridge 8 Cleaning means 12 Intermediate transfer unit 13 Paper feed device 14 Fixing device 15 Secondary transfer unit 16 Secondary transfer means 17 Resist roller vs. 20 Paper discharge roller vs. 21 Paper discharge tray 22 Cleaning device 23 Separation means 24 Development roller 25 Toner container 26 Transfer residual toner container 27 Development rocking center 30 Pressing member 31 Pressed part 32 Biasing member 33 Slide member 34 Contact / separation lever 35 Development contact / separation cam 36 Stay 37 Support means 40 Stay unit 41 Development contact / detachment mechanism 50 Displacement detection mechanism 51 Support member 52 Rotating shaft 53 Swing member 54 Contact part 55 Elastic member (coil spring)
56 Displacement reader (optical sensor)
57 Read part S sheet material 100 Image forming apparatus

Claims (10)

A photoconductor unit having an image carrier and
A developing unit having a developing agent carrier and a container capable of accommodating the developing agent, and rotatably coupled to the photoconductor unit about a rotation axis.
A change amount detection unit that detects a change amount according to the amount of the developer contained in the developing unit, and a change amount detection unit.
A pressing member for pressing the pressed portion of the developing unit corresponding to one side and the other side when the developer carrier is divided at the center in the longitudinal direction is provided.
When the pressing member presses the pressed portion, the developing unit rotates about the rotation axis and takes a developing position for supplying the developing agent from the developing agent carrier to the image carrier. When the pressure on the pressed portion by the pressing member is released, the developing agent carrier is separated from the image carrier and retracted.
When the development unit is in the retracted position, the change amount detection unit regulates the rotation of the development unit to receive a force from the development unit, and the change amount according to the magnitude of the received force. An image forming apparatus characterized by outputting. The image forming apparatus according to claim 1, wherein the change amount detecting unit detects a displacement amount of the developing unit and sets the change amount. The change amount detection unit includes a contact portion arranged at a position capable of contacting the developing unit when the developing unit rotates, and a contact portion.
The contact portion has a reading unit that reads the amount of change according to the displacement of the position of the contact portion when the contact portion comes into contact with the developing unit at the retracted position.
The image forming apparatus according to claim 1 or 2, wherein the change amount detection unit outputs a change amount read by the reading unit. The image forming apparatus according to claim 3, wherein the contact portion is not in contact with the developing unit at the developing position. The change amount detection unit has a swing member that swings around a rotation shaft and an elastic member that urges the swing member toward the developing unit, and the contact portion and the elastic member from the rotation shaft. The image forming apparatus according to claim 3 or 4, wherein the reading unit is arranged in this order. The image forming apparatus according to claim 5, wherein the position of the reading portion is separated from the rotating shaft by the contact portion and the elastic member. The change amount detection unit has a swing member that swings about a rotation axis and an elastic member that urges the swing member toward the developing unit side.
When the change amount detection unit regulates the rotation of the developing unit and receives a force from the developing unit when the developing unit is in the retracted position, the force and the urging force by the elastic member. The image forming apparatus according to any one of claims 1 to 6, wherein the image forming apparatus is balanced. With more controllers
The change amount detection unit includes (i) an optical sensor including a light emitting unit that emits light and a light receiving unit that receives light, and (ii) a transmitting unit that transmits light from the light emitting unit and a light shielding unit that blocks light. It is composed of a repeatedly arranged reading unit and
The image forming apparatus according to claim 1 or 2, wherein the controller performs counting by transmission and shading by the read unit. The change amount detection unit includes a variable resistor.
When the development unit is in the retracted position, the change amount detection unit regulates the rotation of the development unit to receive a force from the development unit, and obtains a variable resistance value according to the received force. The image forming apparatus according to any one of claims 1 to 8, wherein the image forming apparatus is characterized. Any of claims 1 to 9, wherein a part of the change amount detecting unit is arranged outside the developing unit in the longitudinal direction of the developing agent carrier at the same position in the direction of gravity. The image forming apparatus according to item 1.

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