Patent Grant
7095967
The present invention relates to an image developing apparatus, a process cartridge, an electrophotographic image forming apparatus, and a development unit frame.
An electrophotographic image forming apparatus includes an electrophotographic copying machine, an electrophotographic printer (for example, an LED printer, a laser beam printer, and the like), an electrophotographic facsimile apparatus, an electrophotographic word processor, and the like.
A process cartridge is a cartridge which integrally comprises a charging means, a developing meaning or a cleaning means, and an electrophotographic photosensitive member, and is removably installable in the main assembly of an electrophotographic image forming apparatus; and a cartridge which integrally comprises at least a developing means, and an electrophotographic photosensitive member, and is removable installable in the main assembly of an image forming apparatus.
In the past, an image forming apparatus which employed an electrophotographic image formation process employed a process cartridge system, according to which an electrophotographic photosensitive member, and one or a plurality of processing means which work or works on the electrophotographic photosensitive member, are integrally assembled in the form of a cartridge removably installable in the main assembly of an image forming apparatus. Also according to this process-cartridge system, the maintenance for an image forming apparatus can be performed by a user himself or herself; the user does not need to rely on a service person for the maintenance. Therefore, the employment of a process-cartridge system drastically improved the operational efficiency of an image forming apparatus. As a result, a process-cartridge system has been widely used in the field of the image forming apparatus.
In the case of an image forming apparatus such as the above-described electrophotographic image forming apparatus which employs a process-cartridge system, a user himself or herself must exchange a cartridge. Therefore, the image forming apparatus is provided with a means for informing the user of developer depletion, for example, a developer amount detecting apparatus.
In the past, in order to detect the amount of developer remainder, a pair of electrodes in the form of a rod are placed in the developer container of a developing means, and the amount of the developer in the developer container was determined by detecting the changes which occurred to the electrostatic capacity between the two electrodes.
Japanese Laid-Open Patent Application No 100571/1993 discloses a developer amount detecting apparatus, which employs a developer amount detecting member comprising two electrodes placed in the same plane parallel to each other, one being in the shape or a “U”, and the other being in the shape of a “I” so that they can be coupled on the same plane. This developer amount detecting member is located at the bottom portion of the developer container. This development amount detecting apparatus detects the amount of remaining developer by detecting the fluctuation in the electrostatic capacity between the parallel electrodes placed in the same plane.
However, the above described developer amount detecting apparatus is of a type which detects the presence (absence) of the developer within the developer container. More specifically, it is of a type that detects the developer shortage only immediately before the depletion of the developer within the developer container. In other words, it is not enabled to continuously detect how much developer remained in the developer container.
Thus, if it is possible to continuously detect the amount of the developer remaining in the developer container, a user can know the state of developer usage in the developer container, which makes it possible for the user to prepare a new process cartridge for exchange. This is very convenient for the user.
The primary object of the present invention is to provide an image developing apparatus, a process cartridge, and an electrophotographic image forming apparatus, which are capable of continuously detecting the amount of the remaining developer, and a developing apparatus usable for a process cartridge and an electrophotographic image forming apparatus.
Another object of the present invention is to provide an electrophotographic image forming apparatus, which comprises a developer amount detecting means capable of continuously detecting the amount of the remaining developer in accordance with the consumption of the developer within the developer container, to offer more convenience to a user in terms of usage, as well as a process cartridge, a developing apparatus, and a development unit frame, which are compatible with the above electrophotographic image forming apparatus.
Another object of the present invention is to provide a development unit frame better designed for improving the aforementioned process cartridge and developing apparatus in terms of quality and assembly efficiency, and also, for installing the developer amount detecting means, or the like, capable of continuously detecting the amount of the developer in the development chamber in accordance with the developer consumption, into the aforementioned process cartridge or developing apparatus.
According to an aspect of the present invention, a developing apparatus, a process cartridge, or an electrophotographic image forming apparatus which employs a developing apparatus and a process cartridge, comprises: a first electrically conductive portion; a second electrically conductive portion opposing the first electrically conductive portion to provide an electrostatic capacity between the first and second electrically conductive portions; a first electrical contact for receiving the voltage to be applied to the first electrically conductive portion, from the electrophotographic image forming apparatus main assembly; and a second electrical contact for transmitting to the electrophotographic image forming apparatus main assembly, electrical signals generated in accordance with the electrostatic capacity provided between the first and second electrically conductive portions, as voltage is applied to the first electrically conductive portion, in order to enable the electrophotographic image forming apparatus main assembly to detect the amount of the remaining developer.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
Hereinafter, an image developing apparatus, a process cartridge, an electrophotographic image forming apparatus, and a development unit frame, which are in accordance with the present invention will be described in more detail with reference to the appended drawings.
Embodiment 1
First, referring to
A laser beam printer A is provided with an electrophotographic photosensitive member in the form of a drum, that is, a photosensitive drum 7. The photosensitive drum 7 is charged by a charge roller 8, i.e., a charging means. Then, a laser beam modulated with image data is projected onto the photosensitive drum 7, from an optical means 1 comprising a laser diode 1a, a polygon mirror 1b, a lens 1c, and a deflection mirror 1d. As a result, a latent image is formed on the photosensitive drum 7 in correspondence to the image data. This latent image is developed into a toner image, i.e., a visible image, by a developing means 9.
Referring to
Meanwhile, a piece of recording medium 2 is conveyed from a sheet feeder cassette 3a, which stores plural sheets of a recording medium 2, to an image transfer area by a combination of a pickup roller 3b, conveyer roller pairs 3c and 3d, and a registration roller pair 3e, in synchronism with the progress of the toner image formation. In the transfer area, a transfer roller 4, functioning as an image transferring means, is disposed, and as voltage is applied to the transfer roller 4, the toner image on the photosensitive drum 7 is transferred onto the recording medium 2.
After the transfer, the recording medium 2 is conveyed to a fixing means 5 along a conveyer guide 3f, and passed through the fixing means 5, which comprises a driving roller 5c, and a fixing roller 5b containing a heater 5a. As the recording medium 2 is passed through the fixing means 5, the toner image having been transferred onto the recording medium 2 is fixed to the recording medium 2 with the application of heat and pressure from the fixing means 5.
Thereafter, the recording medium 2 is advanced further, is passed through a reversal path 3j, and then, is discharged into a delivery tray 6, by discharge roller pairs 3g, 3h and 3i. The delivery tray 6 is located at the top of the main assembly 14 of the laser beam printer A, i.e., an electrophotographic image forming apparatus. It should be noted here that the recording medium 2 can be discharged from the apparatus main assembly 14, without going through the reversal path 3j, by activating a flapper 3k. In such a case, the recording medium 2 is discharged by a discharge roller pair 3m. In this embodiment, the aforementioned pickup roller 3b, the conveyer roller pairs 3c and 3d, and the registration roller pair 3e, the conveyance guide 3f, the discharge roller pairs 3g, 3h and 3i, and the discharge roller pair 3m, make up the conveying means 3.
After the toner image transfer onto the recording medium 2 by the transfer roller 4, the photosensitive drum 7 is cleaned by a cleaning means 10; the developer remaining on the photosensitive drum 7 is removed by the cleaning means 10. Then, the photosensitive drum 7 is reused for the following cycle of the image formation process. The cleaning means 10 comprises an elastic cleaning blade 10a placed in contact with the photosensitive drum 7. It scrapes away the toner remaining on the photosensitive drum 7 from the photosensitive drum 7, and collects it into a waste toner bin 10b.
Referring to
The process cartridge B is rendered removably installable in the cartridge installing means with which the main assembly 14 of an electrophotographic image forming apparatus is provided. The cartridge installing means in this embodiment is made up of a guiding means 13R (13L) formed as a part of the external right (left) wall of the process cartridge B (
Further, the process cartridge B in this embodiment is provided with a developer amount detecting apparatus as a means capable of continuously detecting the amount of the developer remainder in the development chamber 9A as the developer in the development chamber 9A is consumed.
Referring to
The magnetic developer is attracted to the peripheral surface of the development roller 9a by the magnetic roller 9c contained in the developer roller 9a, and is borne on the peripheral surface of the development roller 9a as the developer 9a is rotated. Then, as the development roller 9a is rotated further, the magnetic developer on the development roller 9a is scraped by the development blade 9d. As a result, an even layer of the magnetic developer is formed on the peripheral surface of the development roller 9a.
The first and second electrodes 81 and 82 are positioned so that the excessive developer scraped away from the development roller 9a enters between them.
The dielectric constant of developer is greater than that of air. Therefore, when there is developer between the first and second electrodes 81 and 82, the electrostatic capacity between the two electrodes is greater than when not. In other words, when a sufficient amount of developer is in the development chamber 9A, a larger electrostatic capacity is provided between them than when not, because, when a sufficient amount of developer is in the development chamber 9A, the aforementioned developer scraped away from the development roller 9a continuously enters between the first and second electrodes 81 and 81. Then, as the developer in the development chamber 9A is consumed, the amount of the developer which enters between the electrodes 81 and 82 gradually decreases, which in turns reduces the electrostatic capacity between them. Thus, the developer amount detecting apparatus continuously detects the developer amount by detecting the change in the electrostatic capacity between the two electrodes.
In order to improve the accuracy with which the developer amount is continuously detected, all that is necessary is to increase the amount of change in the aforementioned electrostatic capacity, by increasing the sizes of the first and second electrodes 81 and 82. In particularly, it is desired that the widths of the opposing surfaces of the first and second electrodes 81 and 83 are rendered greater than the distance between the two electrodes.
Referring to
More specifically, in this embodiment, the first electrode 81 was formed of non-magnetic SUS, and was 14 mm in width (W1), and 0.3 mm in thickness (t1). The second electrode 82 was formed of non-magnetic SUS, and was 17 mm in width (W2), and 0.5 mm in thickness (t2). Arranging these electrodes along and parallel to the development roller 9a in the longitudinal direction produced good results. The configurations of the electrodes 81 and 82 need not be limited to this particular one. However, arranging the electrodes 81 and 82 non-parallel so that the gap between the two electrodes becomes wider on the side from which the developer enters than on the inward side 85, as shown in
Further, in order to increase the surface areas of the electrodes 81 and 82, the electrodes 81 and 82 may be formed on a corrugated, or embossed sheet of material, as shown in
Next, the positioning of the electrodes 81 and 82 in the longitudinal direction will be described. In terms of the longitudinal direction of the development roller 9a, the first and second electrodes 81 and 82 may be extended to a length approximately the same as the length of the image formation range, to increase the aforementioned electrostatic capacity so that the detection accuracy is improved. When the detection accuracy is of somewhat less concern, a pair of narrower electrodes, in terms of the longitudinal direction, may be disposed at either the center, or end, portion of the image-formation range to reduce the cost. In the case of such an arrangement, however, it is not possible to detect whether or not the developer is unevenly distributed in terms of the longitudinal direction. In order to solve such a problem, it is desired that a combination of narrow electrodes 81 and 82 be positioned at each of a plurality of locations; for example, the center and both ends as shown in
Next, referring to
When a process cartridge, more specifically, the developing apparatus portion of the process cartridge, in accordance with the present invention, is used for the first time, no developer is present between the first and second electrodes 81 and 82, although a sufficient amount of developer T is present in the development chamber 9A. In this situation, first, the developer T in the development chamber 9A is sent toward the development roller 9a by the stirring member 9e, and then, is attracted to the peripheral surface of the development roller 9a. Then, as the development roller 9a is rotated, the developer is borne on the peripheral surface of the development roller 9a. As the development roller 9a is rotated further, the developer on the peripheral surface of the development roller 9a is leveled, that is, the excess amount of the developer on the peripheral surface of the development roller 9a is scraped away, and as it is scraped away, it enters between the first and second electrodes 81 and 82, as illustrated in
As the developer T continues to enter into the gap between the first and second electrodes 81 and 82, the gap is filled with the developer T which enters the gap, as illustrated in
Referring to
In the situation illustrated in
In the last stage of toner consumption in the process cartridge B, that is, after the developer in the developer container 11A and development chamber 9A has been virtually entirely consumed, the developer which remains adjacent to the tip of the development blade 9d for scraping away the excess amount of the developer layer on the peripheral surface of the development roller 9a, that is, the developer remaining between the development roller 9a and first electrode 82 is consumed until the developer is completely depleted (END state). During this stage, the resultant prints tend to suffer from white spots.
As is evident from the above description, according to this embodiment, the amount of the developer in the development chamber 9A is determined by measuring the amount of the developer between the first and second electrodes 81 and 82, which can be continuously detected by measuring the electrostatic capacity between the electrodes 81 and 82.
Also according to this embodiment, the structure configuration adjacent to the electrodes 81 and 82 is such that the gap between the first and second electrodes 81 and 82 is provided with no opening at the inward end 85; the gap is provided with only one opening 84, which serves as the entrance as well as the exit. Therefore, widening the gap between the electrodes 81 and 82, on the side of the developer entrance 84 (also, exit), as described above, is effective to allow the developer to easily enter, or come out from, between the two electrodes.
However, if the amount of the developer scraped away from the peripheral surface of the development roller 9a by the development blade 9b per unit of time increases because of the increase in the rotational speed of the development roller 9a, or the like, the amount of the developer entering between the first and second electrodes 81 and 82 also increases, and sometimes, the developer becomes packed herein. If this packing occurs, the developer between the electrodes 81 and 82 cannot circulate, and in this situation, the self weight of the developer, and/or the magnetic force, is not large enough to cause the packed developer to free fall from between the two electrodes, and therefore, the electrostatic capacity between the two electrodes 81 and 82 does not change, which makes it impossible to detect the developer amount. This phenomenon is most likely to occur under a highly humid ambience in which it is easier for the developer to absorb moisture.
Next, the structure for attaching the first and second electrodes 81 and 82 to the developing apparatus portion of the process cartridge B will be described.
The developer amount detecting portion 80 comprising the first and second electrodes 81 and 82 determines the developer amount by detecting the electrostatic capacity between the two electrodes 81 and 82. Therefore, the positional accuracy of the electrodes is extremely important. Further, since the primary object of the present invention is to accurately predict the time when toner depletion occurs, which results in various white spots, the electrodes 81 and 82 should be positioned in the area adjacent the development roller 9a where the developer remains until it is depleted.
Thus, in this embodiment, the first and second electrodes 81 and 82 are attached to the development unit frame 12, as shown in
The first and second electrodes 81 and 82 in this embodiment are formed, of non-magnetic SUS, independently from the development unit frame 12, and then, are attached thereto with an appropriate means, as described above. However, the electrodes 81 and 82 may be directly formed on the development unit frame 12 with the use of such a process as vapor deposition or printing, or may be built into the development unit frame 12, as electrically conductive portions, with the use of a combination of electrically conductive resin and two color molding. Compared to the design in this embodiment in which the electrodes and development unit frame are manufactured independently from each other, these alternative designs produce a much smaller attachment error and/or component size error, and therefore, their employment can improve the positioning accuracy for the electrodes.
Further, when necessary, for example, in a case that the development unit frame 12 is small, the design of the process cartridge B may be modified so that the first and second electrodes 81 and 82 are attached to the front wall 11a of the developer container 11A, as shown in
Further, the process cartridge B design may be modified as shown in
In the preceding portions of this specification, the structural arrangement for continuously detecting the developer amount was described with reference to a case in which magnetic developer was used as the developer for the process cartridge B. However, the present invention is also applicable to various process cartridges comprising a developing apparatus portion which employs non-magnetic developer.
In the case of a developing apparatus structure which employs non-magnetic developer, a developer coating roller 86 is used as a means for supplying the development roller 9a with the developer. The roller 86 is an elastic member formed of sponge or the like, and is rotated in the counter direction to the development roller 9a, in contact with the development roller 9a. The developer is coated on the development roller 9a by the electrostatic force (measured in coulomb) generated by the contact. Immediately prior to the complete depletion of the developer T, the developer T remains above the interface between the development roller 9a and developer coating roller 86. Thus, positioning the first and second electrodes 81 and 82 in the area adjacent to the area above this interface makes it possible to continuously detect the developer amount as in the process cartridge B which employs magnetic developer.
Next, referring to
In this embodiment, the first and second electrodes 81 and 82 are provided with projections 81a and 82a, respectively, as shown in
The development unit frame 12 is provided with a holder 90, which is fixed to the development unit frame 12, at one of the longitudinal end. The holder 90 rotatably supports the development roller 9a with the interposition of a bearing. The holder 90 is provided with a first electrical contact 91 and a second electrical contact 92. The contact portions 91a and 92a, that is, the free ends, of the first and second electrical contacts 91 and 92, respectively, become connected to the aforementioned projections 81a and 82a of the first and second electrodes 81 and 82, respectively, as the holder 90 is fixed to the development unit frame 12, at one of the longitudinal ends.
The contact portions 91b and 92b, that is, the ends opposite to the aforementioned free ends, of the first and second electrical contacts 91 and 92 are fixed to the holder 90, being exposed from the outward surface of the holder 90 so that, as the process cartridge B is installed into the apparatus main assembly 14, they become electrically connected to the contacts 17 and 18 (
With the provision of the above-described structural configuration, as the process cartridge B is installed into the main assembly 14 of an electrophotographic image forming apparatus, voltage is applied from the electrophotographic image forming apparatus main assembly 14 to the first electrode 81 through the first electrical contact 91, and the voltage induced in the second electrode 82, which is in accordance with the electrostatic capacity between the electrodes 81 and 82, is outputted to the electrophotographic image forming apparatus main assembly 14 through the second electrical contact 92. Of course, it is possible that voltage be applied from the electrophotographic image forming apparatus main assembly 14 to the second electrode 82 through the first electrical contact 92, and the voltage induced in the first electrode 81 be outputted to the electrophotographic image forming apparatus main assembly 14 through the second electrical contact 92.
Next, referring to
The detecting portion 80, which has an electrostatic capacity Ca which fluctuates in accordance with the change in the developer amount, comprises an input electrode as an impedance element, that is, the first electrode 81 in this embodiment, and an output electrode, that is, the second electrode 82 in this embodiment. The input electrode is connected to a development bias circuit 101, as a development bias applying means, through the first electrical contact 91, and the output electrode is connected to the control circuit 102 of the developer amount detection circuit 100 through the second electrical contact 92. A reference capacity element (Cb) is also connected to the development bias circuit 101, and establishes a reference voltage V1 for detecting the amount of the remaining developer, with the use of the AC current 11 applied through the bias circuit 101. It is obvious that, as the process cartridge B is installed into the apparatus main assembly 14, the contact 19 (unillustrated in
The control circuit 102 establishes the reference voltage V1 by adding the amount V2 of the voltage drop caused by an AC current I1′, that is, a current shunted by a volume VR1 from the AC current I1 applied to the reference impedance element, and a resistor R2, to voltage V3 established by resistors R3 and R4.
Therefore, an AC current I2 applied to the developer amount detecting portion 80 is inputted into an amplifier 103, and then, is outputted as a voltage V4 (V1−I2×R5) which represents the amount of the remaining developer. Then, its output value is used as the value of the detected amount of the remaining developer.
The image forming apparatus in this embodiment prompts a user to prepare a new process cartridge or a developer supply cartridge, by displaying the consumed amount of the developer determined based on the information obtained by continuously detecting the developer amount between the first and second electrodes 81 and 82, and also prompts a user to exchange the process cartridge, or replenish the process cartridge with a fresh supply of developer, by displaying “OUT OF DEVELOPER” in accordance with the detected depletion of the developer by the aforementioned continuous detection.
Regarding the method for displaying the developer amount, the information obtained by the aforementioned developer amount detecting apparatus is displayed on the monitor screen of a user's personal computer or the like, as shown in
The image forming apparatus main assembly itself may be provided with a display panel, such as an LED based display panel 43 shown in
Embodiment 2
In other words, this embodiment is a duplicate of the first embodiment in terms of the first and second electrically conductive portions (electrodes) 81 and 82, their structures and positioning, developer circulation between the electrodes 81 and 82, the structures surrounding the electrodes 81 and 82, the methods for attaching the electrodes 81 and 82, and the like. Therefore, the descriptions for the structures and functions of the duplicate portions will be omitted.
The primary object of the process cartridge structure in this embodiment is to accurately detect the point in time immediately before the printing errors in the form of white spots begin to be seen in finished prints. All that is necessary to accomplish this object is to detect the developer amount in the area in the process cartridge B, from which the last supply of the developer is consumed. Thus, in this embodiment, the developer amount in the immediate adjacencies of the second and third electrodes 82 and 83, and the development roller 9a, is detected as described in the description of the first embodiment, regarding the developer circulation.
In other words, in the case of the developer amount detecting apparatus in this embodiment, which is illustrated in
With the provision of the above-described structural arrangement, as voltage is applied to the first electrode 81, static electricity is induced between the first and second electrodes 81 and 82 by an amount of Ca, and at the same time, static electricity is also induced between the development roller 9a and third electrode 83 by the development bias applied to the development roller 9a, by an amount of Cc. The development amount is determined by measuring these electrostatic capacities Ca and Cc.
Illustrated In
Referring to
Further, the voltage to be applied to the first electrode 81 is provided from the development bias circuit 101, eliminating the need for an additional power source. Therefore, a cost increase can be avoided.
Further, the contacts are in the form of a single piece, and therefore, there is no stray capacitance, assuring that the electrostatic capacity is accurately measured
As described above, in this embodiment, the developer amount in the process cartridge B is accurately determined by continuously detecting the decrease in the amount of the developer between the electrodes 81 and 82, and the “END” of the developer supply in the process cartridge B is accurately detected by detecting the amount of the developer between the development roller 9a and electrode 83. The relationship between the developer amount and the output of the toner amount detection circuit is graphically shown in
Again referring to
Lengthy routing of wiring increases the chance that static electricity is induced between the adjacent portions of wiring, which in turns reduces detection accuracy. Thus, reducing the distance electric wiring is routed leads to improvement in detection accuracy. Therefore, the second and third electrodes 82 and 83 are desired to be wired as shown in
Embodiment 3
The developing apparatus C in this embodiment is in the form of a cartridge comprising a developer carrier such as a development roller 9a, a development chamber 9A which contains toner to supply the developer carrier with developer, and a plastic development unit frame 11 in which the developer carrier and development chamber 9A are contained. In other words, the developing apparatus C in this embodiment is considered to be a cartridge version of the developing apparatus portion of the process cartridge B in the first and second embodiment described above, that is, a cartridge formed by eliminating the photosensitive drum 7, the charging means 8, and the cleaning means 10, from the process cartridge B. Therefore, all the descriptions given to the structures of the developing apparatus portion and developer amount detecting means portion, in the first and second embodiments, also apply to the developing apparatus in this embodiment. Thus, the description of the structure and function of the developing apparatus in this embodiment will be omitted here, by referring to the preceding descriptions of the first and second embodiment.
Needless to say, the developing apparatus in this embodiment may be provided with the third electrode 83.
As is evident from the descriptions of the preceding embodiments, according to the present invention, the amount of the remaining developer can be accurately and continuously detected.
In the preceding embodiments, the amount of the remaining developer can be continuously detected while the amount of the remaining developer is in a range from approximately 30% down to 0%, provided that the entire amount of the developer contained in the developer container before a process cartridge is put to use for the first time is 100%. However, the application of the present invention does not need to be limited to the preceding embodiment. For example, modifications may be made so that the amount of the remaining developer in the developer container can be continuously detected in a range from 50% down to 0%, or from 40% down to 0%. It should be noted here that “0%” does not means a state of a process cartridge in which the developer has been completely depleted; it also includes another state of a process cartridge in which the amount of the developer in the process cartridge has decreased to a point close enough to disable the image forming apparatus to form images with a predetermined level of quality (development quality).
As described above, according to the first aspect of the present invention, a developing apparatus, a process cartridge, or an electrophotographic image forming apparatus, comprises: a first electrically conductive portion; a second electrically conductive portion opposing the first electrically conductive portion; a first electrical contact for receiving the voltage to be applied to the first electrically conductive portion, from the electrophotographic image forming apparatus main assembly; and a second electrical contact for transmitting to the electrophotographic image forming apparatus main assembly, electrical signals generated in accordance with the electrostatic capacity provided between the first and second electrically conductive portions as voltage is applied to the first electrically conductive portion, in order to enable the electrophotographic image forming apparatus main assembly to detect the amount of the remaining developer. According to the second aspect of the present invention, a developing apparatus, a process cartridge, and an electrophotographic image forming apparatus, comprises: a first electrically conductive portion; a second electrically conductive portion opposing the first electrically conductive portion; a first electrical contact for receiving the voltage to be applied to the first electrically conductive portion, from the electrophotographic image forming apparatus main assembly; a third electrically conductive portion for inducing static electricity between the developer carrying member and itself as voltage is applied to the third electrically conductive portion from the electrophotographic image forming apparatus main assembly; and a second electrical contact for transmitting to the electrophotographic image forming apparatus main assembly, compound electrical signals comprising electrical signals generated in accordance with the electrostatic capacity provided between the first and second electrically conductive portions as voltage is applied to the first electrically conductive portion, and electrical signals generated in accordance with the electrostatic capacity provided between the developer carrying member and third electrically conductive portion as voltage is applied to the developer carrying member, in order to enable the electrophotographic image forming apparatus main assembly to detect the amount of the remaining developer. Therefore, the amount of the remaining developer in the development chamber can be continuously detected as the developer is consumed. Further, the measurement errors, which occur when detecting the amount of the remaining developer on the basis of the fluctuation in the electrostatic capacity between two electrodes, in an unstable ambience, can be eliminated to reduce overall detection error. Therefore, a developing apparatus, a process cartridge, and an electrophotographic image forming apparatus, can be drastically improved in terms of convenience.
Also, according to the first aspect of the present invention, a development unit frame comprises: a portion for supporting a developer carrying member for conveying developer to an electrophotographic photosensitive member to develop an electrostatic latent image formed on the electrophotographic photosensitive member; a portion for supporting a regulating member which regulates the amount of the developer allowed to remain on the peripheral surface of the developer carrying member; a portion for supporting the first electrically conductive portion; and a portion for supporting the second electrically conductive portion in such a way that the second electrically conductive portion opposes the first electrically conductive portion supported by the first electrically conductive portion supporting portion. Also, according to the second aspect of the present invention, a development unit frame comprises: a portion for supporting a developer carrying member for conveying developer to an electrophotographic photosensitive member to develop an electrostatic latent image formed on the electrophotographic photosensitive member; a portion for supporting a regulating member which regulates the amount of the developer allowed to remain on the peripheral surface of the developer carrying member; a portion for supporting the first electrically conductive portion; and a portion for supporting the second electrically conductive portion in such a way that the second electrically conductive portion opposes the first electrically conductive portion supported by the first electrically conductive portion supporting portion; and a portion for supporting the third electrically conductive portion in such a way that the third electrically conductive portion opposes the developer carrying member supported by the developer carrying member supporting portion. Therefore, it is assured that a developer amount detecting means or the like, which can continuously detect the amount of the developer remaining in the development chamber as the developer is consumed, is properly attached to the aforementioned developing apparatus, process cartridge, or electrophotographic image forming apparatus.
As is evident from the above description of the preferred embodiments of the present invention, according to the present invention, it is assured that the amount of the remaining developer can be continuously detected.
While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1998-373834 | Dec 1998 | JP | national |
This application is a divisional application of application Ser. No. 09/469,517, filed Dec. 22, 1999, now U.S. Pat. No. 6,859,627, the entire contents of which are hereby incorporated by reference.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4133453 | Ohbora | Jan 1979 | A |
| 5003917 | Toyoshi et al. | Apr 1991 | A |
| 5198860 | Yamanaka et al. | Mar 1993 | A |
| 5229821 | Fujii | Jul 1993 | A |
| 5294960 | Nomura et al. | Mar 1994 | A |
| 5455665 | Baba et al. | Oct 1995 | A |
| 5475471 | Kisu et al. | Dec 1995 | A |
| 5500714 | Yashiro et al. | Mar 1996 | A |
| 5534344 | Kisu et al. | Jul 1996 | A |
| 5541711 | Kisu et al. | Jul 1996 | A |
| 5543898 | Shishido et al. | Aug 1996 | A |
| 5585895 | Yashiro et al. | Dec 1996 | A |
| 5617579 | Yashiro et al. | Apr 1997 | A |
| 5623328 | Tsuda et al. | Apr 1997 | A |
| 5689774 | Shishido et al. | Nov 1997 | A |
| 5749027 | Ikemoto et al. | May 1998 | A |
| 5765077 | Sakurai et al. | Jun 1998 | A |
| 5768658 | Watanabe et al. | Jun 1998 | A |
| 5768660 | Kurihara et al. | Jun 1998 | A |
| 5774766 | Karakama et al. | Jun 1998 | A |
| 5790923 | Oguma et al. | Aug 1998 | A |
| 5794101 | Watanabe et al. | Aug 1998 | A |
| 5802419 | Sakurai et al. | Sep 1998 | A |
| 5812909 | Oguma et al. | Sep 1998 | A |
| 5828928 | Sasago et al. | Oct 1998 | A |
| 5878310 | Noda et al. | Mar 1999 | A |
| 5884124 | Karakama et al. | Mar 1999 | A |
| 5890036 | Karakama et al. | Mar 1999 | A |
| 5899602 | Noda et al. | May 1999 | A |
| 5920752 | Karakama et al. | Jul 1999 | A |
| 5943528 | Akutsu et al. | Aug 1999 | A |
| 5946522 | Inami | Aug 1999 | A |
| 5966566 | Odagawa et al. | Oct 1999 | A |
| 5987269 | Allen et al. | Nov 1999 | A |
| 6253036 | Karakama et al. | Jun 2001 | B1 |
| 6272299 | Numagami et al. | Aug 2001 | B1 |
| 6343193 | Matsumoto et al. | Jan 2002 | B1 |
| 6463223 | Karakama et al. | Oct 2002 | B1 |
| 6859627 | Karakama et al. | Feb 2005 | B1 |
| Number | Date | Country |
|---|---|---|
| 2128676 | Dec 1997 | CA |
| 0 586 042 | Mar 1994 | EP |
| 0 770 932 | May 1997 | EP |
| 0 840 182 | May 1998 | EP |
| 2-197880 | Aug 1990 | JP |
| 4-355477 | Dec 1992 | JP |
| 5-100571 | Apr 1993 | JP |
| 9-190067 | Jul 1997 | JP |
| 9-211960 | Aug 1997 | JP |
| 57-154268 | Sep 2002 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20050025508 A1 | Feb 2005 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 09469517 | Dec 1999 | US |
| Child | 10934416 | US |
