Patent Application
20180067419
None.
The present disclosure relates generally to electrophotographic image forming devices and more particularly to a capacitive toner level sensor for an electrophotographic image forming device.
During the electrophotographic printing process, an electrically charged rotating photoconductive drum is selectively exposed to a laser beam. The areas of the photoconductive drum exposed to the laser beam are discharged creating an electrostatic latent image of a page to be printed on the photoconductive drum. Toner particles are then electrostatically picked up by the latent image on the photoconductive drum creating a toned image on the drum. The toned image is transferred to the print media (e.g., paper) either directly by the photoconductive drum or indirectly by an intermediate transfer member. The toner is then fused to the media using heat and pressure to complete the print.
The image forming device's toner supply is typically stored in one or more replaceable units installed in the image forming device. As these replaceable units run out of toner, the units must be replaced or refilled in order to continue printing. Further, residual or waste toner generated during the printing process is also typically stored in a replaceable unit installed in the image forming device. When the replaceable unit holding waste toner fills, it must be emptied or replaced in order to accommodate additional waste toner. As a result, it is desired to measure the amount of toner remaining in these units in order to warn the user that a replaceable unit storing the toner supply is near an empty state or that a replaceable unit storing waste toner is near a full state. Accordingly, a system for measuring the amount of toner remaining in a replaceable unit of an image forming device is desired.
A toner container according to one example embodiment includes a housing having a reservoir for holding toner. A rotatable shaft is positioned in the reservoir and has a rotational axis. A toner agitator is rotatably coupled to the rotatable shaft. A first electrical conductor and a second electrical conductor are positioned on the housing. The first electrical conductor and the second electrical conductor form a capacitor having a capacitance that changes in response to a change in an amount of toner in the reservoir between the first electrical conductor and the second electrical conductor. The first electrical conductor includes a rod positioned in the reservoir at the rotational axis of the rotatable shaft and extending along the rotational axis of the rotatable shaft.
A toner container according to another example embodiment includes a housing having a cylindrical reservoir for holding toner. The reservoir has a generally circular cross-sectional shape. A first electrical conductor and a second electrical conductor are positioned on the housing. The first electrical conductor and the second electrical conductor form a capacitor having a capacitance that changes in response to a change in an amount of toner in the reservoir between the first electrical conductor and the second electrical conductor. The first electrical conductor includes an arc-shaped sheet that extends along a wall of the housing that forms the reservoir. The arc-shaped sheet curves along at least a portion of the generally circular cross-sectional shape of the reservoir.
A toner container according to another example embodiment includes a housing having a reservoir for holding toner. A first electrical conductor and a second electrical conductor are positioned on the housing. The first electrical conductor and the second electrical conductor form a capacitor having a capacitance that changes in response to a change in an amount of toner in the reservoir between the first electrical conductor and the second electrical conductor. The first electrical conductor includes a rod having a longitudinal axis. The second electrical conductor includes a sheet that extends along the longitudinal axis of the rod and is spaced from the rod.
The accompanying drawings incorporated in and forming a part of the specification, illustrate several aspects of the present disclosure, and together with the description serve to explain the principles of the present disclosure.
In the following description, reference is made to the accompanying drawings where like numerals represent like elements. The embodiments are described in sufficient detail to enable those skilled in the art to practice the present disclosure. It is to be understood that other embodiments may be utilized and that process, electrical, and mechanical changes, etc., may be made without departing from the scope of the present disclosure. Examples merely typify possible variations. Portions and features of some embodiments may be included in or substituted for those of others. The following description, therefore, is not to be taken in a limiting sense and the scope of the present disclosure is defined only by the appended claims and their equivalents.
Referring now to the drawings and particularly to
In the example embodiment shown in
Controller 28 includes a processor unit and associated memory 29. The processor may include one or more integrated circuits in the form of a microprocessor or central processing unit and may be formed as one or more Application-specific integrated circuits (ASICs). Memory 29 may be any volatile or non-volatile memory or combination thereof such as, for example, random access memory (RAM), read only memory (ROM), flash memory and/or non-volatile RAM (NVRAM). Alternatively, memory 29 may be in the form of a separate electronic memory (e.g., RAM, ROM, and/or NVRAM), a hard drive, a CD or DVD drive, or any memory device convenient for use with controller 28. Controller 28 may be, for example, a combined printer and scanner controller.
In the example embodiment illustrated, controller 28 communicates with print engine 30 via a communications link 50. Controller 28 communicates with imaging unit 32 and processing circuitry 44 thereon via a communications link 51. Controller 28 communicates with toner cartridge 35 and processing circuitry 45 thereon via a communications link 52. Controller 28 communicates with media feed system 38 via a communications link 53. Controller 28 communicates with scanner system 40 via a communications link 54. User interface 36 is communicatively coupled to controller 28 via a communications link 55. Processing circuitry 44, 45 may provide authentication functions, safety and operational interlocks, operating parameters and usage information related to imaging unit 32 and toner cartridge 35, respectively. Controller 28 processes print and scan data and operates print engine 30 during printing and scanner system 40 during scanning.
Computer 24, which is optional, may be, for example, a personal computer, including memory 60, such as RAM, ROM, and/or NVRAM, an input device 62, such as a keyboard and/or a mouse, and a display monitor 64. Computer 24 also includes a processor, input/output (I/O) interfaces, and may include at least one mass data storage device, such as a hard drive, a CD-ROM and/or a DVD unit (not shown). Computer 24 may also be a device capable of communicating with image forming device 22 other than a personal computer such as, for example, a tablet computer, a smartphone, or other electronic device.
In the example embodiment illustrated, computer 24 includes in its memory a software program including program instructions that function as an imaging driver 66, e.g., printer/scanner driver software, for image forming device 22. Imaging driver 66 is in communication with controller 28 of image forming device 22 via communications link 26. Imaging driver 66 facilitates communication between image forming device 22 and computer 24. One aspect of imaging driver 66 may be, for example, to provide formatted print data to image forming device 22, and more particularly to print engine 30, to print an image. Another aspect of imaging driver 66 may be, for example, to facilitate collection of scanned data from scanner system 40.
In some circumstances, it may be desirable to operate image forming device 22 in a standalone mode. In the standalone mode, image forming device 22 is capable of functioning without computer 24. Accordingly, all or a portion of imaging driver 66, or a similar driver, may be located in controller 28 of image forming device 22 so as to accommodate printing and/or scanning functionality when operating in the standalone mode.
Print engine 30 includes a laser scan unit (LSU) 31, toner cartridge 35, imaging unit 32, and a fuser 37, all mounted within image forming device 22. Imaging unit 32 is removably mounted in image forming device 22 and includes a developer unit 34 that houses a toner sump and a toner delivery system. In one embodiment, the toner delivery system utilizes what is commonly referred to as a single component development system. In this embodiment, the toner delivery system includes a toner adder roll that provides toner from the toner sump to a developer roll. A doctor blade provides a metered uniform layer of toner on the surface of the developer roll. In another embodiment, the toner delivery system utilizes what is commonly referred to as a dual component development system. In this embodiment, toner in the toner sump of developer unit 34 is mixed with magnetic carrier beads. The magnetic carrier beads may be coated with a polymeric film to provide triboelectric properties to attract toner to the carrier beads as the toner and the magnetic carrier beads are mixed in the toner sump. In this embodiment, developer unit 34 includes a magnetic roll that attracts the magnetic carrier beads having toner thereon to the magnetic roll through the use of magnetic fields.
Imaging unit 32 also includes a cleaner unit 33 that houses a photoconductive drum and a waste toner removal system. Toner cartridge 35 is removably mounted in image forming device 22 in a mating relationship with developer unit 34 of imaging unit 32. An outlet port on toner cartridge 35 communicates with an entrance port on developer unit 34 allowing toner to be periodically transferred from toner cartridge 35 to resupply the toner sump in developer unit 34.
The electrophotographic printing process is well known in the art and, therefore, is described briefly herein. During a printing operation, laser scan unit 31 creates a latent image on the photoconductive drum in cleaner unit 33. Toner is transferred from the toner sump in developer unit 34 to the latent image on the photoconductive drum by the developer roll (in the case of a single component development system) or by the magnetic roll (in the case of a dual component development system) to create a toned image. The toned image is then transferred to a media sheet received by imaging unit 32 from media input tray 39 for printing. Toner may be transferred directly to the media sheet by the photoconductive drum or by an intermediate transfer member that receives the toner from the photoconductive drum. Toner remnants are removed from the photoconductive drum by the waste toner removal system. The toner image is bonded to the media sheet in fuser 37 and then sent to an output location or to one or more finishing options such as a duplexer, a stapler or a hole-punch.
Referring now to
With reference to
With reference to
With reference to
With reference to
In the embodiment illustrated, conductor 154 includes a curved sheet 158 positioned along a wall 160 of housing 102 forming reservoir 104. Sheet 158 may be positioned along an inner surface 160a of wall 160, inside of reservoir 104, or along an outer surface 160b of wall 160, outside of reservoir 104. Positioning sheet 158 along inner surface 160a may provide more accurate toner level sensing but positioning sheet 158 along outer surface 160b may provide assembly advantages. In the example embodiment illustrated, sheet 158 is positioned along an underside of reservoir 104, underneath rod 156. The positioning of sheet 158 along the underside of reservoir 104 may allow for more accurate detection of the toner level in reservoir 104 as the toner level approaches an empty condition. In other embodiments, sheet 158 is positioned along other portions of reservoir 104, such as, for example, the front, rear and/or top of reservoir 104, instead of or in addition to the underside of reservoir 104. Sheet 158 extends along a longitudinal axis 157 of rod 156. In the embodiment illustrated, sheet 158 is concave with respect to rod 156 in a circumferential direction with respect to longitudinal axis 157. In the example embodiment illustrated, sheet 158 forms an arc that spans roughly 140 degrees around rod 156 in the lower half of reservoir 104. However, sheet 158 may span less than 140 degrees or as much as 360 degrees around rod 156 as desired. Sheet 158 may have a fixed radius of curvature or the radius of curvature of sheet 158 may vary. The radius of curvature of sheet 158 may be centered about longitudinal axis 157 or another point, preferably near longitudinal axis 157. The curvature of sheet 158 may be uniform axially along longitudinal axis 157 or the curvature of sheet 158 may vary axially along longitudinal axis 157.
While the example embodiment illustrated includes a curved sheet 158, other shapes may be utilized as desired, such as, for example, a stepped or multi-faceted sheet 158. Further, while the example embodiment illustrated includes a continuous sheet 158, sheet 158 may include cutouts, windows, extensions, segments, etc.
While the example embodiments discussed above include rod 156 forming conductor 152 used to sense a capacitance value and sheet 158 forming the additional conductor 154, this configuration may be reversed as desired such that sheet 158 forms conductor 152 used to sense a capacitance value and rod 156 forms the conductor 154.
Further, some embodiments include more than one sheet 158. For example,
In the example embodiment illustrated, reservoir 104 is cylindrical with a generally circular cross-sectional shape, which is preferred in order to reduce the amount of unused toner in reservoir 104. For example, if the cross-sectional shape of reservoir 104 includes corners, indentations or offset pockets, it may be difficult to move toner from those areas of reservoir 104 to outlet port 128. Positioning rod 156 along the rotational axis 133 of drive shaft 132 and sheet 158 along a curved wall 160 that forms reservoir 104 allows for the detection of the toner level in reservoir 104 without restricting the operation of toner agitator assembly 140. If, on the other hand, rod 156 was replaced with an electrically conductive plate extending along a central portion of reservoir 104, the plate would tend to interfere with or limit the reach of paddles 142. Further, if rod 156 was omitted and instead sheets 158 and 158′ served as conductors 152 and 154, respectively, the capacitance measured would be dominated by the composite dielectric constant of the substance present between sheets 158 and 158′ at their frontmost and rearmost ends, where sheets 158 and 158′ are closest to each other, rather than along the entire arc of sheets 158, 158′ as measured with rod 156 and sheet(s) 158, 158′.
While the example embodiment illustrated in
Toner cartridge 100 is not limited to the example embodiment illustrated and may take many different configurations. For example,
Although the example embodiments illustrated include a capacitive toner level sensor positioned in the reservoir of a toner cartridge, it will be appreciated that a capacitive toner level sensor may be positioned in any toner reservoir, such as, for example, the toner sump of developer unit 202 or a reservoir for storing waste toner removed by the waste toner removal system of cleaner unit 204. Further, although the example embodiments include a pair of replaceable units in the form of a toner cartridge and an imaging unit, it will be appreciated that the replaceable unit(s) of the image forming device may employ any suitable configuration as desired. For example, in one embodiment, the main toner supply for the image forming device, the developer unit, and the cleaner unit are housed in one replaceable unit. In another embodiment, the main toner supply for the image forming device and the developer unit are provided in a first replaceable unit and the cleaner unit is provided in a second replaceable unit. Further, although the example image forming device 22 discussed above includes one toner cartridge and corresponding imaging unit, in the case of an image forming device configured to print in color, separate replaceable units may be used for each toner color needed. For example, in one embodiment, the image forming device includes four toner cartridges and four corresponding imaging units, each toner cartridge containing a particular toner color (e.g., black, cyan, yellow and magenta) and each imaging unit corresponding with one of the toner cartridges to permit color printing.
The foregoing description illustrates various aspects of the present disclosure. It is not intended to be exhaustive. Rather, it is chosen to illustrate the principles of the present disclosure and its practical application to enable one of ordinary skill in the art to utilize the present disclosure, including its various modifications that naturally follow. All modifications and variations are contemplated within the scope of the present disclosure as determined by the appended claims. Relatively apparent modifications include combining one or more features of various embodiments with features of other embodiments.
