Patent Application
20180143564
The present disclosure relates to a developer container, a developing apparatus, a process cartridge, and an image forming apparatus.
Here, “image forming apparatus” refers to an apparatus which forms an image on a recording material. “Process cartridge” refers to a cartridge which at least has an image carrying member. In many cases, the cartridge is an integrated cartridge including a charging unit, a developing unit, a cleaning unit, and an image carrying member, and is detachably attached to an apparatus main body of the image forming apparatus. “Developing apparatus” refers to an apparatus which at least has a developer carrying member. In many cases, “developing apparatus” refers to an integrated apparatus in which a developer carrying member and a developing frame which supports the developer carrying member are integrated with each other, and is detachably attached to an apparatus main body of the image forming apparatus. “Developer container” refers to a container which contains developer.
An electrophotographic image forming apparatus may be a copier, an LED printer, a laser printer, a facsimile machine, and so forth.
In an electrophotographic image forming apparatus (hereinafter, “image forming apparatus”), a usually drum-shaped electrophotographic photoconductor serving as an image carrying member, i.e., a photoconductive drum, is uniformly charged.
Next, by selectively exposing the charged photoconductive drum, an electrostatic latent image (an electrostatic image) is formed on the photoconductive drum. Then, the electrostatic latent image formed on the photoconductive drum is developed as a toner image with toner serving as developer.
Then, the toner image formed on the photoconductive drum is transferred to a recording material, such as a recording sheet or a plastic sheet, and the toner image is fixed to the recording material by applying heat and pressure to the toner image transferred to the recording material, whereby an image is recorded.
Generally, toner needs to be replenished and various process units need to be maintained in this type of image forming apparatus. In order to make maintenance and the replenishment of toner easy, the photoconductive drum, the charging unit, the developing unit, the cleaning unit, etc. are integrated in a frame as a process cartridge which is detachably attached to an apparatus main body of the image forming apparatus. A process cartridge such as that described is in practical use.
With this process cartridge system, since maintenance of the apparatus can be performed by a user, operability can be improved significantly. Therefore, an image forming apparatus with significantly high usability can be provided. Therefore, this process cartridge system is widely used in image forming apparatuses.
In the image forming apparatus employing the process cartridge system described above, a user replaces the process cartridge themselves. Therefore, the image forming apparatus often includes a unit to detect the consumption of toner and inform the user when it is time to replace the process cartridge (i.e., a residual toner detection unit). In an exemplary residual toner detection unit, a toner amount is detected using a change in electrostatic capacitance which changes when the amount of space occupied by toner between a pair of input output electrodes changes (Japanese Patent Laid-Open No. 2001-117346).
Japanese Patent Laid-Open No. 2001-117346 proposes a plate antenna system which includes a pair of input output electrodes, and detects a toner amount by measuring electrostatic capacitance between the two electrodes. Japanese Patent Laid-Open No. 2016-142881 proposes a structure in which styrene resin in which carbon black is dispersed is used as electrodes serving as antennas.
When manufacturing a developer container as proposed in Japanese Patent Laid-Open No. 2016-142881, there is a risk of the issues illustrated in
Resin J poured from gates 92r and 92l spreads concentrically (see
As the resin is further poured and molding is further performed, the flows of resin poured in from the gates 92r and 92l merge with each other (a confluence G) (see
This can cause a linear mark (a weld line) W to be produced from the confluence G (see
If a conductive resin sheet which contains resin is used for the electrodes serving as the antennas, deformation and a projection occur in the resin sheet depending on the type of the poured resin. If the resin is poured in the state in which the resin sheet is placed at the position of the confluence G of
As a result, when the developer container is manufactured, a projection N projecting from an end portion 30b located downstream in a moving direction of the resin is formed in the resin sheet on the frame of the developer container, as illustrated in
An embodiment of the present disclosure is a manufacturing method for a developer container capable of detecting a developer amount using a change in electrostatic capacitance between a first electrode and a second electrode, including: holding a first resin sheet which will become the first electrode and a second resin sheet which will become the second electrode having a recess in a mold in a manner such that the recess is located to face an end portion of the first resin sheet, and molding the developer container which includes the first resin sheet and the second resin sheet by pouring resin from a first inlet and a second inlet through which resin is poured, wherein in the molding, the recess is disposed in an area in which a confluence in which first resin poured from the first inlet and second resin poured from the second inlet merge is formed.
The present disclosure provides a developer container, a developing apparatus, a process cartridge, and an image forming apparatus.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Hereinafter, embodiments for implementing the present disclosure will be described in detail with reference to the drawings. It is to be noted that dimensions, materials, shapes, relative arrangements, and so forth of the components described in the embodiments described below are changeable depending on the structure of the apparatus or various conditions to which the present disclosure is applied. Those dimensions, materials, shapes, relative arrangements, and so forth do not limit the scope of the present disclosure to the following embodiments.
(this sentence is in the above paragraph)In this specification, a direction in which the rotational axes of the electrophotographic photoconductive drum, the developing roller, and the developing sleeve extend is defined as the longitudinal direction.
In the longitudinal direction of the electrophotographic photoconductive drum, which is the image carrying member, the side on which the electrophotographic photoconductive drum receives driving force from the apparatus main body of an image forming apparatus is defined as a driving side, and the opposite side is defined as a non-driving side.
The entire structure and an image formation process will be described with reference to
The image forming apparatus illustrated in
In the apparatus main body A, a pickup roller 5a, a feeding roller pair 5b, a conveyance roller pair 5c, a transfer guide 6, a transfer roller 7, a conveyance guide 8, a fixing device 9, a discharge roller pair 10, a discharge tray 11, and so forth are sequentially disposed along a conveyance direction D of the sheet material P. The fixing device 9 is constituted by a heating roller 9a and a pressure roller 9b.
Next, an image formation process will be described schematically. In accordance with a print start signal, the electrophotographic photoconductive drum (hereinafter, “drum 62”) is driven to rotate at a predetermined circumferential speed (a process speed) in the direction of arrow R.
A charging roller 66 which is a charging member to which a bias voltage is applied is in contact with an outer peripheral surface of the drum 62 to uniformly charge the outer peripheral surface of the drum 62.
The exposure apparatus 3 outputs laser light L in accordance with image information. The laser light L passes through a laser opening 71h provided in a cleaning frame 71 of the cartridge B, and scan-exposes the outer peripheral surface of the drum 62. Therefore, an electrostatic image and an electrostatic latent image corresponding to the image information are formed on the outer peripheral surface of the drum 62.
As illustrated in
The toner T serving as the developer is carried on a surface of a developing roller 32 which is the developer carrying member and is the developing sleeve by magnetic force of a magnet roller 34 (a stationary magnet).
The toner T is triboelectrically charged on a circumferential surface of the developing roller 32 and a layer thickness of the toner T is regulated by a developing blade 42 which is a developer layer regulating member.
The toner T is developed on the drum 62 in accordance with the electrostatic latent image, and is visualized as a toner image which is a developer image.
As illustrated in
The sheet material P to which the toner image has been transferred is separated from the drum 62 and conveyed to the fixing device 9 along the conveyance guide 8. The sheet material P passes through a nip portion formed by the heating roller 9a and the pressure roller 9b which constitute the fixing device 9. The toner image is fixed to the sheet material P through fixing processing with pressure and heat in the nip portion. The sheet material P to which the toner image is fixed is conveyed to the discharge roller pair 10 and is discharged to the discharge tray 11.
As illustrated in
In the present embodiment, the charging roller 66 which is the charging member, the developing roller 32 which is the developer carrying member, the transfer roller 7 which is the transfer member, and the cleaning blade 77 which is the cleaning member are processing units which act on the drum 62 which is the image carrying member.
Next, attachment and removal of the cartridge B to and from the apparatus main body A will be described with reference to
The door 13 is pivotally attached to the apparatus main body A. When the door 13 is opened, a cartridge insertion opening 17 appears. In the cartridge insertion opening 17, the tray 18 for attaching the cartridge B to the apparatus main body A is provided. When the tray 18 is drawn out to a predetermined position, the cartridge B can be attached and removed. The cartridge B, placed on the tray 18, is attached to the inside of the apparatus main body A along a guide rail (not illustrated) in the direction of arrow C.
A first drive shaft 14 and a second drive shaft 19 for respectively transmitting driving force to a first coupling 70 and a second coupling 21 (see
As illustrated in
As supported portions of the cartridge B, a supported portion 73b and a supported portion 73d of a drum bearing 73, a driving side boss 71a, a non-driving side projection 71f and a non-driving side boss 71g of the cleaning frame 71 are provided. The supported portion 73b is supported by the driving side first support portion 15a, the supported portion 73d is supported by the driving side second support portion 15b, and the driving side boss 71a is supported by the rotary support portion 15c. The non-driving side projection 71f is supported by the non-driving side first support portion 16a and the non-driving side second support portion 16b, and the non-driving side boss 71g is supported by the rotary support portion 16c. Therefore, the cartridge B is positioned within the apparatus main body A.
Next, the entire structure of the cartridge B will be described with reference to
The cartridge B is a process cartridge which includes the cleaning unit 60 and the developing unit 20. Generally, the process cartridge is an integrated cartridge consisting of the photoconductive drum which is the image carrying member and is the electrophotographic photoconductor, and a process unit which acts on the photoconductive drum. The process cartridge is detachably attached to the apparatus main body of the electrophotographic image forming apparatus. The process unit may be a charging unit, a developing unit, and a cleaning unit.
As illustrated in
The cleaning member 77 includes a rubber blade 77a which is a blade-shaped elastic member formed of rubber as an elastic material, and a support member 77b which supports the rubber blade. The rubber blade 77a is in contact with the drum 62 in the direction opposite to the rotational direction of the drum 62. That is, the rubber blade 77a is in contact with the drum 62 in a manner such that an end portion of the rubber blade 77a faces the upstream side of the drum 62 in the rotational direction.
As illustrated in
Upon reception of driving force from a main body driving motor (not illustrated) which is a driving source, the drum 62 is driven to rotate in the direction of arrow R in accordance with an image forming operation.
The charging roller 66 is rotatably attached to the cleaning unit 60 via a charging roller bearing 67 at both longitudinal ends of the cleaning frame 71 (substantially parallel to the direction of the rotational axis of the drum 62). The charging roller 66 is pressed against the drum 62 since the charging roller bearing 67 is pressed toward the drum 62 by the urging member 68. The charging roller 66 is rotated following the rotation of the drum 62.
As illustrated in
As illustrated in
The cleaning unit 60 includes the cleaning frame 71, the lid member 72, the drum 62, and the drum bearing 73 which rotatably supports the drum 62, and a drum shaft 78. On the driving side, as illustrated in
As illustrated in
As illustrated in
Specifically, at both longitudinal ends of the developing unit 20, a development first support hole 23a and a development second support hole 23b are provided in the developer container 23. At both longitudinal ends of the cleaning unit 60, first hanging holes 71i and second hanging holes 71j are provided in the cleaning frame 71. When the connection pin 69 press-fitted into and fixed to the first hanging holes 71i is fitted into the development first support hole 23a, and when the connection pin 69 press-fitted into and fixed to the second hanging holes 71j is fitted into the development second support hole 23b, the cleaning unit 60 and the developing unit 20 are connected to each other so as to be pivotable with respect to each other.
A first hole 46Ra of a driving side urging member 46R is hung on a boss 73c of the drum bearing 73, and a second hole 46Rb of the driving side urging member 46R is hung on a boss 26a of the driving side development side member 26.
A first hole 46Fa of a non-driving side urging member 46F is hung on a boss 71k of the cleaning frame 71, and a second hole 46Fb of the non-driving side urging member 46F is hung on a boss 37a of the bearing member 37.
In the present embodiment, the driving side urging member 46R and the non-driving side urging member 46F are formed by tension springs. With the urging force of the tension spring, the developing unit 20 is urged against the cleaning unit 60, and the developing roller 32 is reliably pressed toward the drum 62. The developing roller 32 is held with a predetermined space from the drum 62 by the spacing members 38 attached at both ends of the developing roller 32.
Developer amount detection will be described with reference to
As illustrated in
When a voltage in which an AC voltage and a DC voltage are superimposed is applied to the developing roller 32 from a development bias power supply 51, a current corresponding to the electrostatic capacitance between the developing roller 32 and the second electrode 31 is induced between the developing roller 32 and the second electrode 31.
When a voltage in which an AC voltage and a DC voltage are superimposed is applied to the first electrode 30 from the development bias power supply 51, a current corresponding to the electrostatic capacitance between the first electrode 30 and the second electrode 31 is induced between the first electrode 30 and the second electrode 31. Here, electrostatic capacitance between the developing roller 32 and the second electrode 31 changes depending on the toner amount between the developing roller 32 and the second electrode 31, and electrostatic capacitance between the first electrode 30 and the second electrode 31 changes depending on the toner amount between the first electrode 30 and the second electrode 31.
A change in the value of a current flowing in the second electrode 31 is measured by a developer amount detection apparatus in the apparatus main body A via a contact point provided in the cartridge B and a main body contact point of the apparatus main body.
The first electrode 30 and the second electrode 31 are disposed below the first conveyance member 43 along the bottom surface of the toner chamber 29 with a distance L2 therebetween. The distance L2 is located at the lowermost portion of the toner chamber 29. The shaft 43a of the first conveyance member is disposed immediately above the distance L2.
The first conveyance member 43 is constituted by the shaft 43a and the conveying portion 43b of the flexible sheet shaped member. The shaft 43a is rotatably supported, and the conveying portion 43b conveys toner on the bottom surface of the toner chamber 29 through rotational driving of the shaft 43a. Therefore, the conveyed toner passes through the distance L2 on the bottom surface of the toner chamber 29.
Since the distance L2 between the first electrode 30 and the second electrode 31 is provided at the position described above, even when the amount of toner in the toner chamber 29 becomes small, the toner amount can be measured accurately.
Therefore, a voltage V1 is generated in the reference capacitor 54 and a voltage V2 is generated in the first electrode 30 in accordance with the current according to composite electrostatic capacitance.
A detection circuit 55 generates a voltage V3 from a voltage difference between the voltage V1 and the voltage V2 and outputs the voltage V3 to an AD conversion unit 56.
The AD conversion unit 56 outputs a result of digital conversion of the analog voltage V3 to a control unit 57. The control unit 57 determines a level of residual toner which is a developer amount from this result, stores the result in a storage medium 58, and displays the residual toner level on a display unit 59.
Manufacture of the developer container will be described with reference to
As illustrated in
In the present embodiment, the first electrode 30 and the second electrode 31 are formed integrally with the bottom member 22.
Although described later, the first electrode 30 and the second electrode 31 are formed by conductive resin sheets.
The mold is constituted by a first mold 90 and a second mold 91, each of which has a shape which will become a surface shape of the bottom member 22 when transferred.
The first mold 90 has an inlet (a gate) 92 through which resin is poured into a hollow (a cavity) 93 inside of the mold.
First, when the mold of
Very small air holes are formed in the mold at positions denoted by “S” to suction the first electrode 30 and the second electrode 31, and the air holes are connected to a suction unit, which is not illustrated. Then, the first electrode 30 and the second electrode 31 are held by (or fixed to) the second mold 91 (a holding process) by suctioning.
The first electrode 30 and the second electrode 31 are held by (or fixed to) the second mold 91 in the present embodiment, however, these electrodes do not necessarily have to be held by (or fixed to) the second mold, and may be held by (or fixed to) the first mold 90. Alternatively, these electrodes may be held (or fixed) by other known methods.
Next, as illustrated in
Molten resin is poured into the hollow (the cavity) 93 through a gate 92 formed when the molds are fitted together. Then, the bottom member 22 is molded.
When the resin is poured into the hollow (the cavity) 93, the bottom member 22 is shaped and, at the same time, the first electrode 30 and the second electrode 31 adhere to the molded bottom member 22, and an integrated molded article is thus formed.
Resin is poured in from a plurality of inlets. Therefore, a confluence in which a flow of resin poured from a first inlet and a flow of resin poured from a second inlet which is different from the first inlet merge with each other is formed within the hollow (the cavity) 93. If the resin is further poured in after the confluence is formed, the confluence will expand. The expanded confluence is also referred to as a weld line W. The confluence melts or pulls on a part of the electrode which is resin, and forms an extension of the electrode.
When the first mold 90 and the second mold 91 are fitted together, since the first mold 90 and the second mold 91 face each other at a distance M, the distance M is defined as a thickness M of the bottom member 22.
Although two resin sheets for the first electrode 30 and the second electrode 31 are inserted into the mold in the description above, any numbers of resin sheets may be inserted as necessary in the same manner.
The developer container is formed by welding together the bottom member which is the molded second frame to which the first electrode 30 and the second electrode 31 are adhered, and the developer container which is the first frame by ultrasonic welding.
In this specification, the process until molding the bottom member which is the second frame, and welding the developer container which is the first frame and the bottom member which is the second frame together to form the developer container is referred to as a forming step.
The first electrode 30 and the second electrode 31 are formed by conductive resin sheets.
In the present embodiment, 0.1 mm-thick resin sheets are used. In the present embodiment, “a material having conductivity” refers to a material having surface resistivity of 10 kΩ/sq or below, and “a material having no conductivity” refers to a material having surface resistivity greater than 10 kΩ/sq when measured by a method prescribed by JIS K 7194.
As a material of conductive resin sheets, ethylene-vinyl acetate copolymer (EVA)-based resin in which carbon black is dispersed is used.
In the present embodiment, by bonding EVA-based resin to PS-based resin with heat and pressure during molding of the bottom member 22 by the molding process described above, the first electrode 30, the second electrode 31, and the bottom member 22 which are the conductive resin sheets are formed integrally.
However, the configuration is not restricted to this example, and resin sheets of other thicknesses or other combinations of resin materials may also be employed.
More specifically, in the present embodiment, a 0.1 mm-thick resin sheet is selected from the viewpoint of the influence on the deformation of the frame, transferability to the frame shape, and conductivity, however, the thickness of the resin sheet may be suitably changed. An EVA-based resin having adhesiveness with the material of the bottom member 22 is selected as the material of the resin sheets, however, a resin which melts with the resin of the bottom member 22 and having compatibility with the resin of the bottom member 22 so as to be capable of integrating therewith with no interface may be used as the material of the resin sheets.
In the present embodiment, a thermal deformation temperature (a glass transition temperature) of the resin used for the bottom member 22 is about 90° C., and the thermal deformation temperature of ethylene-vinyl acetate copolymer (EVA)-based resin used for a developer amount detection member which is a conductive resin sheet is about 80° C.
The thermal deformation temperatures of the bottom member 22, the first electrode 30, and the second electrode 31 are illustrative only and not restrictive.
The thermal deformation temperature of the resin which forms the conductive sheet member may be lower than the thermal deformation temperature of the resin which forms the frame.
The bottom member 22 will be described with reference to
A plurality of gates may be provided since the number of the gates 92 may change depending on the size of the frame to be formed. In the present embodiment, a two-point gate is employed. A first gate is defined as a gate 92r and a second gate is defined as a gate 92l of the gate 92 of the bottom member 22.
The resin in the hollow 93 during molding described above flows toward an end of the shape to be molded from the first gate 92r and the second gate 92l. Therefore, the first gate 92r and the second gate 92l are defined as the most upstream points, and the end portion of the shape (the bottom member) to be molded is defined as being downstream. In
The shape of the bottom member 22 is formed during molding when the resin poured in from the gates 92r and 92l flows to the downstream side from the upstream side.
The first electrode 30 will be described with reference to
When seen from an axial direction of the developing roller as illustrated in
In the present embodiment, a relationship between the distance L2 and the distance L1 is L2<L1.
An area in which the distance between the first electrode 30 and the second electrode 31 will become L1 with the existence of the notch 30c is located in an area H between the first gate 92r and the second gate 92l. In particular, the area in which the distance between the first electrode 30 and the second electrode 31 will become L1 is located in the confluence in which the resin poured in from the first gate 92r and the resin poured from the second gate 92l merge with each other in the hollow (the cavity) 93 within the mold, and an area corresponding to a thin line (a weld line) produced at a portion in which the resin merge with each and melt together. That is, the confluence is formed by the poured resin. When resin is further poured after the confluence is formed, the weld line W is formed in the vertical direction of
Regarding the first electrode 30, the distance L1 between the downstream end 30d of the notch of the first electrode 30 and the upstream end of the second electrode 31 is provided. This is in order that even if the projection N is produced in an area corresponding to the weld line W of the first electrode 30 illustrated in
The recess of the first electrode is located at an intermediate point between the gate 92r and the gate 92l. Therefore, the lower end portion 30d of the recess of the first electrode of the present embodiment is provided at the same distance from the gate 92r and the gate 92l. In a manufactured developer container or the like, an inlet vestige is formed by resin when the resin is poured from the gate which is the inlet. Therefore, the distance between the inlet vestige and the electrode, the distance between the inlet vestige and the bottom portion of the recess, etc. can be determined also from the molded article.
Unless otherwise specified, functions, materials, shapes, relative arrangements thereof, and so forth of the components described in the present embodiment are illustrative only and not restrictive.
Next, a second embodiment of the present disclosure will be described with reference to the drawings.
In the present embodiment, differences from the first embodiment will be described in detail. Unless otherwise specified, materials, shapes, etc. are the same as those of the first embodiment. The same components are denoted by the same reference numerals and not described in detail.
A bottom member 22 which is a part of a developer container will be described with reference to
A first electrode 30 will be described with reference to
A distance between the first electrode 30 located at the most lower portion of a toner chamber 29 along a bottom surface of the toner chamber 29 described above and the second electrode 31 (
The distance between the downstream end 30b of the first electrode 30 and the upstream end 31a of the second electrode 31 is L4. Since a notch 31c of a recessed shape is formed at a part of the upstream end 31a of the second electrode 31, the distance L4 will become a distance L3 in this portion. In the present embodiment, the distance to the corresponding center of the first electrode 30 in the longitudinal direction (the longitudinal center) from the notch which is the recess of the second electrode 31 is the distance L3.
The relationship between the distance L4 and the distance L3 is L4<L3.
As described above, the same effects as those of the first embodiment described above can be obtained by providing the notch 31c in the second electrode 30.
The notch 31c which is a recess does not necessarily be disposed at the longitudinal center, but may be disposed in an area on a confluence produced by pouring of resin. For example, the recess may be provided at one longitudinal end of the electrode.
Various alternative embodiments will be described.
Although the recess is triangular in shape in the first and the second embodiments, the shape of the recess is not limited to the same. The recess may be quadrangular, rectangular, trapezoidal, and semicircular in shape. The structure of the cartridge is not limited to the process cartridge structure described in the first and the second embodiments. For example, there are a developer container which contains developer (e.g., a toner cartridge), and a developing apparatus which at least includes a developer carrying member (e.g., a developing cartridge).
Here, in the developing apparatus, the developing apparatus itself has a frame containing the developer, and when the contained developer is used up, the developing apparatus itself is replaced. Alternatively, the developing apparatus may have a developer container containing developer which is detachably attached to the developing apparatus. In this case, in the developing apparatus, the developer can be replenished from the developer container to a space which can contain the developer of the frame which supports the developer carrying member.
Only the process cartridge may be detachably attached to the apparatus main body of the image forming apparatus, or both the developing cartridge and the drum cartridge may be detachably attached to apparatus main body of the image forming apparatus. If two cartridges are to be attached, after attaching the developing cartridge to the drum cartridge, these cartridges may be attached to the apparatus main body of the image forming apparatus. Alternatively, these cartridges may be attached separately to the apparatus main body regardless of the attachment state of other cartridge.
Although a structure to which a single cartridge is detachably attached is described, a plurality of cartridges may also be detachably attached. For example, if the apparatus is a color image forming apparatus, the same four types of yellow, magenta, cyan, and black (YMCK) cartridges may be detachably attached.
While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure 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.
This application claims the benefit of Japanese Patent Application No. 2016-226554 filed Nov. 22, 2016, and No. 2017-199623 filed Oct. 13, 2017, which are hereby incorporated by reference herein in their entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-226554 | Nov 2016 | JP | national |
| 2017-199623 | Oct 2017 | JP | national |
