Patent Application
20090263146
The present application relates to electrophotographic printing. More specifically, the application relates to a system and method for calculating an amount of toner in a toner container located within a electrophotographic printing machine.
In the well-known process of electrophotographic printing, a charge retentive surface, typically known as a photoreceptor, is electrostatically charged, and then exposed to a light pattern of an original image to selectively discharge the surface in accordance therewith. The resulting pattern of charged and discharged areas on the photoreceptor form an electrostatic charge pattern, known as a latent image, conforming to the original image. The latent image is developed by contacting it with a finely divided electrostatically attractable toner which is held on the image areas by the electrostatic charge on the photoreceptor surface. Thus, a toner image is produced in conformity with a light image of the original being reproduced. The toner image may then be transferred to a substrate or support member (e.g., paper), and the image affixed thereto to form a permanent record of the image to be reproduced.
The electrophotographic process is useful for light lens copying from an original as well as printing electronically generated or stored originals such as with a raster output scanner (ROS), where a charged surface may be image wise discharged in a variety of ways.
Existing electrophotographic printing machines are commonly supplied with replaceable containers which hold the toner. Typically, such a container is positioned horizontally within the printing machine, and therefore gravity does not ensure movement of the toner towards the latent image. Thus a mechanism, such as an auger, is needed to move the toner. One particular container design is a cylindrical container having an opening near one end and internal spiral ribs, which when rotated urges the toner to the opening. Such containers are also called bottles or cartridges among other names.
A method and system to sense an amount of material such as toner in a container held in a horizontal position within a machine, such as a printing machine. A level sensor senses an amount of material within a dispensing unit which causes the level sensor to issue a signal. The dispensing unit is external to the container. The container holding the material is rotated, and a rotation direction reversed to a direction normally used to dispense the material. The reverse rotation direction moves the material to a closed end of the container. The container is then moved in a forward direction following the rotation of the container in the reverse direction. The forward rotation moves the material to the open end of the container, and the material further moves into the dispensing unit. A signal is generated when a sufficient amount of material has been moved into the dispensing unit. A time period is determined which represents the time it took to move the material from the closed end of the material, until the signal indicating a sufficient amount of material exists in the dispensing unit. The amount of material in the container is estimated by use of the determined time period.
Next, the charged portion of photoconductive surface 12 is advanced through exposure station B. At exposure station B, an original document 30 is positioned on a raster input scanner (RIS) 32. The RIS captures the entire original document and converts it to a series of raster scan lines and (for color printing) measures a set of primary color densities. This information is transmitted to an image processing system (IPS) 34, which is the control electronics used to prepare and manage the image data flow to raster output scanner (ROS) 36. A user interface (UI) 38, is in communication with the IPS. The UI enables the operator to control the various operator adjustable functions. The output signal from the UI is transmitted to IPS 34. The signal corresponding to the desired image is transmitted from IPS 34 to ROS 36, which creates the output copy image. ROS 36 lays out the image in a series of horizontal scan lines with each line having a specified number of pixels per inch.
After the electrostatic latent image has been recorded on photoconductive surface 12, belt 10 advances the latent image to development station C. At development station C, a development system 38, develops the latent image recorded on the photoconductive surface. The chamber in toner housing 40 stores a supply of toner 42 in a toner container 44 held in place by supports 46. Also shown is a sump housing 48. The toner may be a two component toner of at least magnetic carrier granules having toner particles adhering triboelectrically thereto. It should be appreciated that the toner may likewise comprise a one component toner consisting primarily of toner particles.
After the electrostatic latent image has been developed, belt 10 advances the developed image to transfer station D, at which a copy sheet 50 is advanced by roll 51 and guides 52 into contact with the developed image on belt 10. A corona generator 53 is used to spray ions onto the back of the sheet so as to attract the toner image from belt 10 the sheet. As the belt turns around roller 18, the sheet is stripped, with the toner image thereon.
After transfer, the sheet is advanced by a conveyor (not shown) to fusing station E. Fusing station E includes a heated fuser roller 54 and a back-up roller 55. The sheet passes between fuser roller 54 and back-up roller 55 with the toner powder image contacting fuser roller 54. In this way, the toner powder image is permanently affixed to the sheet. After fusing, the sheet advances through chute 56 to catch tray 57 for subsequent removal from the printing machine by the operator.
After the sheet is separated from photoconductive surface 12 of belt 10, the residual toner particles adhering to photoconductive surface 12 are removed at cleaning station F by a rotatably mounted fibrous brush 58 in contact with photoconductive surface 12. Subsequent to cleaning, a discharge lamp (not shown) floods photoconductive surface 12 with light to dissipate any residual electrostatic charge.
It is believed that the foregoing description is sufficient for purposes of the present application to illustrate the general operation of an electro-photographic printing machine which is capable of incorporating the concepts of the present application.
Turning to
Container 44 also includes a ring shaped portion 65 which extends from open end 61. The ring shaped portion 65 includes radial protrusions 66 which extend inwardly from interior periphery 67.
The radial protrusions 66 have a carrying face 68 which curves in the direction of rotation 69 of container 44 as the radial protrusions 66 extend toward centerline 70 of container 44. The radial protrusions 66 thereby form pockets 74 along carrying face 68. Pockets 74 become filled with toner 42 from open end 61 and carry toner 42 along inner periphery 67.
Container 44 further includes a plate shaped end portion 76 which extends from a second face 78 of ring shaped portion 65. Plate shaped portion 76 includes first end 49 as well as opening 47. Plate shaped portion 76 also includes an interior hub 80 which extends inwardly from a disc area 82 of end portion 76. A puncturable seal 84 is located within interior hub 80. Seal 84 serves to contain toner 42 during installation and removal of container 44. To provide sealing in addition to puncturable seal 84 when container 42 is installed into the machine, a secondary seal 86 is located in interior hub 80 spaced outwardly from and parallel to puncturable seal 84. The secondary seal 86 contains a central opening 88 which slidably fits over an auger tube 114 (see
Turning to
Included in this figure is a toner level sensor 100 connected, via a signal line 102, to an input of controller 104. Level sensor 100 senses the amount of toner in dispensing unit 94, and depending on the amount of toner in dispensing unit 94 it issues a signal to controller 104 informing controller 104 as to the status of toner in dispensing unit 94. An output of controller 104 is in operative communication with motor 98, and controls operation of motor 98. For example, when sensor 100 indicates a depleted toner level, in normal operation motor 98 is energized, causing the container to rotate in direction 69, whereby internal rib 63 migrates the toner to the open end of the container and into the dispensing unit 94. Once sensor 100 senses sufficient toner and supplies this signal to controller 104, the controller signals motor 98 to stop, thereby stopping rotation of container 44. By this design, toner is delivered to the system to ensure a continuous supply during imaging operations. However, while this system is effective for supplying toner when there is sufficient toner in the container, it does not address the issue of determining when the container is low or nearly empty and will need to be replaced with another container which is full of toner.
Turning now to
As illustrated in
When the toner reaches the open end of the container, the toner is picked up by an auger system for dispensing the toner into the dispenser unit 94, as in the normal operation. The time period it takes the innermost toner (e.g., 106 of
The signal generated by level sensor 100 may be considered a trigger signal which initiates the level sensing operation.
The triggering of the level sensor 100 may occur due to operation of an algorithm/software program stored within a memory area of controller 104. Where, when the program is run within a computation area (e.g., CPU) of the controller, the controller a lows the toner within the dispensing unit to drop below the trigger threshold. For example, the program may simply stop motor 98 from continuing the normal rotation of the container when the toner level sensor has signaled for additional toner, and rather initiates the process described in connection with
The amount of time from the start of the forward rotation until the toner sensor is again replenished is used to determine the amount of toner remaining in container 44. In one embodiment, the elapsed time is recorded in the controller and is used in a transfer function derived from normal engineering calculations to determine the amount of remaining toner. Parameters which may be considered in the development of the transfer function include the size of the container, speed of rotation, density of the toner, among others.
An alternative procedure to determine the amount of toner within a container is to obtain empirical data through repetitive testing. Where the results of the tests are correlated the amount of toner within the container. Particularly, a table can be generated by redundant testing wherein, for example, the container is filled with a known amount of toner. Then the system is operated in accordance with the concepts of
Results of both above embodiments alone or in combination can then be used by the printing device to issue low toner alerts to a user. Such alerts may be generated via existing audio or visual components which are part of the printing machine. In some embodiments controller 104 includes an electronic display which issues a low toner alert which would be visible to a user and/or a speaker system which issues an audible alert.
In one embodiment, the steps shown in
In one embodiment, the motor drive 98 and gearing/transmission system 96 may use a one-way clutch in the gear train connecting the toner container and the pick-up auger drive (see
Referring now to
Development system 38 includes toner housing 40 from which the bottle supports 46 extend. A sump housing 48 extends upwardly from one end of the toner housing 40. A toner dispensing unit (or feed mechanism) 94 extends through sump housing 48 and outwardly therefrom in the direction of centerline 110. The feed mechanism 94 extends through opening 47 of container 44, centerline 110 being co-linear with centerline 70. Feed mechanism 94 is in the form of auger 112 located within tube 114. The tube 114 preferably has an inlet opening 116 in the upper portion of the tube 114 near a first end 118 of tube 114. The tube 114 also has an outlet opening 120 in the bottom portion of tube 114 near second end 122 of tube 114. The development system 38 further includes container drive motor 98 which may be located anywhere within development system 38. The container drive motor 98 serves to rotate container 44 as well as auger 112. It should be appreciated, however, that a separate motor for auger 112 and a separate motor for the marking particle container 44 may be used. Any suitable gear train of gearing arrangement 96 which allows for reverse rotation of container 44, while inhibiting reverse rotation of the auger 112 may be used. For example, motor 98 may have a pinion gear 124 extending inwardly therefrom. A sun gear 126 slidably rotates about tube 114 and meshes with pinion gear 124.
To urge sun gear 126 against container 44 and assure the mating of pins 90 with stops 128, preferably, the development system 38 further includes a spring 130 slidably fitted about tube 114 between the sump housing 48 and second face 132 of sun gear 126. To interconnect container 44 to feed mechanism 94, stops 128 are located on face 132 of sun gear 126 and are aligned adjacent pins 90 of container 44 to cooperate therewith.
To assure container 44 is adequately axially positioned relative to feed mechanism 94, a stop 134 located preferably on toner housing 40 secures container 44 by restraining closed end 62 of container 44. A series of gears 134 preferably interconnect drive motor 98 to the auger 112. The gears 134 are so configured that when motor 98 rotates in the direction of arrow 136, auger 112 will be rotated in a direction to urge the toner 42 from the inlet opening 116 to the outlet opening 120. When motor 98 rotates in the direction of arrow 136′, causing reverse rotation of container 44 (i.e., the operation shown in
The development system 38 further preferably includes a toner auger 138 extending from bottom of the sump housing 48. The auger 138 extends outwardly along the length of toner housing 40. The auger 138 is located within conduit 140. The conduit 140 includes one or more dump holes 142 which permit toner 42 to enter the toner housing 40. Auger 130 can be driven by a toner auger motor 144 to independently control the flow of toner 42 from sump housing 48 to the toner housing 40.
Particles of toner 42 fall into inlet opening 116 of the tube 114 and are thereby carried away by the auger 112.
Particles received at inlet opening 116 translate along auger 112 in the direction of arrow 146 toward outlet opening 120. The toner particles exit the tube 114 at outlet opening 120 and fall to the bottom 140 of the sump housing 48. Auger 138 then carries the marking particles along conduit 140 and through dump holes 142 to the toner housing 40 where they are used in the developing process.
While the foregoing has been described in conjunction with various embodiments, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, while the foregoing discussion has focused on toner material other materials may also take advantage of the described concepts. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims.
It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
