Patent Application
20090304400
This disclosure relates generally to a customer replaceable unit (CRU) or a field support engineer (tech rep) replaceable unit (ERU) for a printing machine. More particularly, the present disclosure relates to monitors for customer replaceable units and engineer replaceable units.
In a typical electrographic or xerographic copying or printing process, a charge retentive surface such as a photoconductive member is charged to a substantially uniform potential so as to sensitize the surface thereof. The charged portion of the photoconductive member is selectively exposed to light to dissipate the charges thereon in areas subjected to the light. This records an electrostatic latent image on the photoconductive member. After the electrostatic latent image is recorded on the photoconductive member, the electrostatic latent image is rendered visible by bringing one or more developer materials into contact therewith. Generally, the developer material comprises toner particles adhering triboelectrically to carrier granules. The toner particles are attracted from the carrier granules either to a donor member or to a latent electrostatic image on the photoconductive member. When attracted to a donor member, the toner particles are subsequently deposited on the latent electrostatic images. The toner powder image is then transferred from the photoconductive member to a final substrate or imaging media. The toner particles forming the toner powder images are then subjected to a combination of heat and/or pressure to permanently affix the powder images to the substrate.
A fuser assembly is commonly used to heat the toner material and cause it to fuse to the substrate. The assembly includes a fuser roll that rotates around an axis as the substrate is drawn between it and a pressure roll. Heat is applied to the toner material via the fuser roll during this drawing process. Fuser rolls typically operate at temperatures up to approximately 200° C.
Many machines have replaceable sub-assemblies. Printing machines, for example, may have a number of replaceable sub-assemblies such as a fuser print cartridge, a toner cartridge, or an automatic document handler. These subassemblies may be arranged as unit called a cartridge, and if intended for replacement by the customer or machine owner, may be referred to as a CRU. Examples of a CRU may include a printer cartridge, a toner cartridge, or a transfer assembly unit. It may be desirable for a CRU design to vary over the course of time due to manufacturing changes or to solve post-launch problems with either the machine, the CRU, or a CRU and machine interaction. Further, design optimizations may be recognized subsequent to design launch and machine sale that a relatively simple code update might realize. However, solving these problems, or providing optimization updates, generally requires a field service call to accomplish.
U.S. Pat. No. 6,016,409 to Beard et al. discloses a fuser module which includes an electronically readable memory permanently associated therewith. The control system of the printing apparatus reads out codes from the electronically-readable memory at installation to obtain parameters for operating the module, such as maximum web use, voltage and temperature requirements, and thermistor calibration parameters.
The fuser roll that is a component of the fuser module may be replaced independently of the other fuser module components. Accordingly, it would be advantageous to have a monitor installed on the fuser roll, and not as part of the entire fuser module assembly. However, the hostile environment to which fuser rolls are subjected, 200° C., exceeds the limits of conventional monitor devices, generally less than 125° C.
There is provided a replaceable unit monitor assembly comprising a substrate member, multiple thermal insulating stand-off members adapted to mount the substrate member to an end hub of a fuser roll of a printing machine, and a monitor device mounted on the substrate member.
The substrate member is ring-shaped, having oppositely disposed front and back surfaces and oppositely disposed inner and outer edges.
The substrate member may be composed of a high temperature ceramic or a thermoset laminate material.
A first set of the stand-off members are mounted to the inner edge of the circuit substrate member. The first set of stand-off members is adapted for mounting to an outer shaft face of the fuser roll end hub.
A second set of the stand-off members may be mounted to the back surface of the circuit substrate member. The second set of stand-off members is adapted for mounting to a front face of the fuser roll end hub.
Each of the stand-off members has a thickness of 1 to 3 millimeters. The. stand-off members are composed of thermal insulating ceramic material.
The monitor device includes a monitor circuit and an antenna in communications with the monitor circuit. The monitor circuit and the antenna may be connected to the front surface of the substrate member, with the antenna having a C-shape. The monitor circuit may be connected to the front surface of the substrate member, with the antenna being connected to the back surface of the substrate member and having an annular shape.
The present disclosure may be better understood and its numerous objects and advantages will become apparent to those skilled in the art by reference to the accompanying drawings in which:
With reference to the drawings wherein like numerals represent like parts throughout the several figures, a replaceable unit monitor assembly for use on a fuser roll of a printing machine in accordance with the present disclosure is generally designated by the numeral 10, 10′.
A monitor device is hereby defined to be a device having a memory, capable of storing at least a fixed datum, and a communications element. With reference to
The substrate member 18 is mounted to one of the fuser roll end hubs 20. Fuser roll cores 22 are generally maintained at temperatures on the order of 200° C. during normal operation. Fuser roll cores 22 and end hubs 20 are conventionally composed of aluminum and stainless steel, respectively. Since there is a relatively high heat transfer coefficient between the materials, the end hubs 20 are generally also at temperatures on the order of 200° C. during normal operation. The monitor circuit 14 must be kept below 125° C., and preferably below 85° C. to prevent premature failure of the circuit 14. Interposing thermal insulators 24 between the fuser roll end hubs 20 and the substrate member 18 allows the monitor device 12, 12′ to be mounted to the fuser roll 26 without subjecting it to temperatures that will cause premature failure.
The substrate member 18 is ring-shaped, having oppositely disposed front and back surfaces 28, 30 and oppositely disposed inner and outer edges 32, 34. The substrate member 18 may be a high temperature ceramic, such as Kyocera™ A-493 sintered alumina, or a thermoset laminate material, such as Acculam™ G-7. The thermal insulators or stand-off members 24 are composed of thermal insulating ceramic material, for example zirconium oxide ceramic, that substantially prevents conductive transfer of heat from the fuser roll end hubs 20 to the circuit substrate member 18. In one variation, the stand-off members 24 are monolithic protrusions of the material of the substrate member 18 that extend from the back surface 30 of the substrate member 18.
In the embodiment of
In the embodiment of
The monitor circuit 14 cannot be hard-wired to the copier since the fuser roll 26 rotates during operation. Accordingly, the antenna 16, 16′ is required to provide power to the monitor circuit 14 and to provide communications with the copier. In the second embodiment 10′, the monitor circuit 14 is mounted to the front surface 28 of the circuit substrate member 18 and the antenna 16′ is mounted on the back surface 30 of the circuit substrate member 18. Accordingly, the antenna 16′ forms a complete annulus around the fuser roll shaft 48. This means that the antenna 16′ will always be adjacent the active antenna region 50 of the coupler/communications board 46 ensuring that communications with the monitor device 12′ is always possible. However, it is not necessary that the antenna 16, 16′ completely surround the circuit substrate member central opening in order to achieve good communications.
For example, in the first embodiment 10′, both the antenna 16 and the monitor circuit 14 are mounted on the front surface 28 of the circuit substrate member 18, creating a “C” shaped antenna 16. The monitor circuit 14 occupies only a small segment of the circuit substrate member front surface 28, with the remaining segment of the circuit substrate member front surface 28 being occupied by the antenna 16. Although such a configuration may result in a disruption in communications, such a disruption may be eliminated or reduced to an insignificant value by selection of the speed of rotation of fuser roller, shaft diameter, data packet size, the amount overlap of the antennas, etc.
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.
