Image forming devices, imaging assemblies of image forming devices, and methods of forming an image upon media

Information

  • Patent Grant
  • 6393227
  • Patent Number
    6,393,227
  • Date Filed
    Friday, September 8, 2000
    24 years ago
  • Date Issued
    Tuesday, May 21, 2002
    22 years ago
Abstract
The present invention includes image forming devices, imaging assemblies, sensors, and methods of forming an image. One aspect of the present invention provides an image forming device including a housing configured to guide media along a media path: an input device configured to receive an image; a sensor adjacent the media path and configured to monitor the media and to generate a signal responsive to the monitoring; and an imager adjacent the media path and configured to provide developing material corresponding to the image upon the media according to an imaging parameter and to adjust the imaging parameter responsive to the signal.
Description




FIELD OF THE INVENTION




The present invention relates to image forming devices, imaging assemblies, sensors, and methods of forming an image.




BACKGROUND OF THE INVENTION




Electrophotographic processes for forming images upon media are well known in the art. Typically, these processes include an initial step of charging a photoreceptor which may be provided in the form of a drum or continuous belt having photoconductive material. Thereafter, an electrostatic latent image may be produced by exposing the charged area of the photoreceptor to a light image using a light-emitting diode array, or scanning the charged area with a laser beam in exemplary configurations.




Particles of toner may be applied to the photoreceptor upon which the electrostatic latent image is disposed such that the toner particles are transferred to the electrostatic latent image. Thereafter, a transfer step occurs wherein the toner particles are transferred from the photoreceptor to the media while maintaining the shape of the image formed upon the photoreceptor. A fusing step is utilized to fix the toner particles in the shape of the image to the media. A subsequent step can include cleaning or restoring the photoreceptor for a next printing cycle.




Two operational parameters greatly affect the final print quality of the toner image supplied to the media. For example, the electric field in the transfer nip of an electrophotographic printing device and an effective temperature in the fuser nip are vital to ensure optimized image quality and achievable print. Two variables in printing media that affect the electric fields in the transfer nip and the effective temperature in the fuser nip are basis weight and water content. These two variables manifest themselves as differences in dielectric thickness, heat capacity and thermal conductivity for a given media in an environment.




Referring to toner transfer operations, toner transfer electric fields are largely dependent upon the capacitance of the media. Most transfer systems of conventional electrophotographic devices use constant supply voltages that are applied to respective conductive transfer rollers. Typically, the applied voltages are set relatively high to accommodate thicker (i.e., lower capacitance) media. Unfortunately, this condition can result in less than optimum electric fields for thinner (i.e., higher capacitance) media. In some conventional arrangements, a user can manually adjust fuser temperatures using a control panel or software. Typically, such adjustments are made after problems in fusing quality are noticed.




The above conventional image forming system configurations have associated drawbacks of requiring knowledge of the user to implement transfer and fusing adjustments as well as knowledge of the proper adjustment to improve transfer and fusing quality. Therefore, a need exists to provide image forming devices and methods which provide improved print quality for different types of media.




SUMMARY OF THE INVENTION




The present invention includes image forming devices, imaging assemblies, sensors, and methods of forming an image. One aspect of the present invention provides an image forming device comprising: a housing configured to guide media along a media path; an input device configured to receive an image; a sensor adjacent the media path and configured to monitor the media and to generated signal responsive to the monitoring: and an imager adjacent the media path and configured to provide developing material corresponding to the image upon the media according to an imaging parameter and to adjust the imaging parameter responsive to the signal.




A second aspect of the invention provides an imaging assembly of an image forming device comprising: a sensor configured to monitor media traveling along a media path of an image forming device and to generate a signal responsive to the monitoring; a controller coupled with the sensor and configured to receive the signal and to adjust an imaging parameter responsive to the signal; and an imager adjacent the media path and coupled with the controller and configured to provide developing material upon the media according to the imaging parameter.




According to another aspect, the invention provides a sensor configured to monitor media comprising: a first electrode positioned adjacent a first surface of media to be monitored; a second electrode positioned adjacent a second surface of the media; and wherein the first electrode and second electrode are substantially aligned to form a capacitor, and the media provides a dielectric material intermediate the first electrode and the second electrode.




Another aspect of the present invention includes a method of forming an image upon media comprising: providing an image forming device; providing an image; transferring developing material corresponding to the image to media according to an imaging parameter; monitoring the media; and adjusting the imaging parameter responsive to the monitoring.




Other features and advantages of the invention will become apparent to those of ordinary skill in the art upon review of the following detailed description, claims, and drawings.











DESCRIPTION OF THE DRAWINGS




Preferred embodiments of the invention are described below with reference to the following accompanying drawings.





FIG. 1

is an isometric view of an image forming device.





FIG. 2

is a cross-sectional view of the image forming device of FIG.


1


.





FIG. 3

is an illustrative representation of an imager and a fuser of the image forming device.





FIG. 4

is a functional block diagram of exemplary control circuitry of the image forming device.





FIG. 5

is an illustrative representation of transfer operations of the imager.





FIG. 6

is an illustrative representation of an exemplary sensor configuration provided upstream of the imaging assembly.





FIG. 7

is a schematic representation of exemplary conditioning circuitry.





FIG. 8

is functional block diagram illustrating exemplary operations of the image forming device.





FIG. 9

is a graphical representation of a relationship of transfer electrical fields and dielectric thickness of media.











DETAILED DESCRIPTION OF THE INVENTION




The protection sought is not to be limited to the disclosed embodiments, which are given by way of example only, but instead is to be limited only by the scope of the appended claims.




Referring to

FIG. 1

, an exemplary image forming device


10


embodying the present invention is illustrated. The depicted image forming device


10


comprises an electrostatographic printer, such as an electrophotographic or electrographic printer. In alternative embodiments, image forming device


10


is provided in other configurations, such as facsimile or copier configurations.




The illustrated image forming device


10


includes a housing


12


arranged to house internal components (not shown in FIG.


1


). A user interface


14


is provided upon an upper surface of housing


12


. User interface


14


includes a key pad and display in an exemplary configuration. A user can control operations of image forming device


10


utilizing the key pad of user interface


14


. In addition, the user can monitor operations of image forming device


10


using the display of user interface


14


. An outfeed tray


16


is also provided within the upper portion of housing


12


. Outfeed tray


16


is arranged and positioned to receive outputted printed media. Outfeed tray


16


provides storage for convenient removal of the printed media from image forming device


10


. Exemplary media includes paper, transparencies, envelopes, etc.




Referring to

FIG. 2

, various internal components of an exemplary configuration of image forming device


10


are shown. The depicted image forming device


10


includes a media supply tray


20


, sensor


22


, imager


24


, developing assembly


26


, fuser


28


, and controller


30


. A media path


32


is provided through image forming device


10


. Plural rollers are provided along media path


32


to guide media in a downstream direction from media supply tray


20


towards outfeed tray


16


. More specifically, a pick roller


34


, feed rollers


36


, transport rollers


38


, registration rollers


40


, conveyor


42


, delivery rollers


44


, and output rollers


46


are arranged as shown to guide media along media path


32


.




Image forming device


10


includes an input device


50


configured to receive an image in the described printer configuration. An exemplary input device


50


includes a parallel connection coupled with an associated computer or network (not shown). Such a coupled computer or network could provide digital files (e.g., page description language (PDL) files) corresponding to an image to be produced within image forming device


10


.




Developing assembly


26


is positioned adjacent media path


32


and provides developing material, such as toner, for forming images. Developing assembly


26


is preferably implemented as a disposable cartridge for supplying such developing material.




Sensor


22


is positioned adjacent media path


32


and monitors media being printed upon and generates a characteristic signal responsive to the monitoring. Sensor


22


can monitor one or more properties of the media. More specifically, sensor


22


can be configured to determine a qualitative characteristic and/or quantitative characteristic of media being printed upon and generate the characteristic signal indicative of the qualitative and/or quantitative characteristics. As described below, sensor


22


can be configured to monitor qualitative characteristics, such as the electrical capacitance of the media.




Sensor


22


can additionally monitor quantitative characteristics, such as physical dimensions (e.g., physical thickness) of the media. Sensor


22


is preferably positioned to cause minimal vibration of media sheets


18


being monitored so as to not interfere with the static adhesion of developing material


61


to media sheets


18


.




Imager


24


is positioned adjacent media path


32


and provides developing material upon media passing adjacent imager


24


corresponding to an image received via input


50


. Fuser


28


is adjacent media path


32


and is located downstream from imager


24


within image forming device


10


. Fuser


28


fuses the developing material corresponding to the received image to the media.




Referring to

FIG. 3

, further details of image forming operations of image forming device


10


are described. The depicted imager


24


includes an imaging roller


52


and transfer roller


54


. Imaging roller


52


is a photoconductor which is insulative in the absence of incident light and conductive when illuminated. Imaging roller


52


may be implemented as a belt in an alternative configuration.




Imaging roller


52


rotates in a clockwise direction with reference to FIG.


3


. The rotating imaging roller


52


is charged uniformly by a charging device such as charging roller


56


. Charging roller


56


provides a negative charge upon the surface of imaging roller


52


in the described configuration. A laser device


58


scans across the charged surface of imaging roller


52


and writes an image to be formed by selectively discharging areas upon imaging roller


52


where toner is to be printed. A developer


60


applies developing material


61


adjacent imaging roller


52


. Negatively-charged developing material


61


is attracted to discharged areas upon imaging roller


52


corresponding to the image and repelled from charged areas thereon.




A media sheet


18


traveling along media path


32


passes imaging roller


52


and transfer roller


54


at a transfer nip


62


. Media sheet


18


can comprise an individual sheet or one sheet of a continuous web. The developed image comprising the developing material is transferred to media sheet


18


within transfer nip


62


. A bias voltage is applied to transfer roller


54


positioned below passing media sheet


18


in FIG.


3


.




Application of the voltage bias to transfer roller


54


induces an electric field through media sheet


18


. The magnitude of the induced field is determined by the bias voltage, the resistivity of media sheet


18


and the dielectric thickness of media sheet


18


. As described in detail below, an imaging parameter, such as the bias voltage, can be adjusted responsive to the media being printed upon to provide optimum transfer of developing material


61


according to one aspect of the present invention.




The induced electric field causes the developing material


61


to move from imaging roller


52


to media sheet


18


. Residual developing material (not shown) upon imaging roller


52


may be removed at cleaning station


64


to prepare imaging roller


52


for the application of a subsequent image.




Fuser


28


is positioned downstream of imager


24


. Media travels in a downstream direction from imager


24


to fuser


28


. Fuser


28


includes a fusing roller


66


and a pressure roller


68


. Fusing roller


66


and pressure roller


68


are in contact at fuser nip


69


. Media sheet


18


having developing material


61


thereon passes from imager


24


to fuser


28


.




Media sheet


18


passes fusing roller


66


and pressure roller


68


at fuser nip


69


. Fusing roller


66


preferably includes an internal heating element to impart heat flux to developing material


61


upon media sheet


18


as well as media sheet


18


itself. Application of such heat flux from fusing roller


66


fuses developing material


61


cohesively to media sheet


18


. Temperatures of fusing roller


66


for providing optimum fusing are dependent upon the properties of developing material


61


, the velocity of media sheet


18


, the surface finish of media sheet


18


, and the thermal conductivity and heat capacity of media sheet


18


. Control of fusing operations responsive to media properties is described in detail in a U.S. patent application entitled “Image Forming Devices, Fusing Assemblies and Methods of Forming an Image”, filed on the same day as the present U.S. patent application, naming Michael J. Martin, Nancy Cernusak, John Hoffman, Jeffrey S. Weaver, James G. Bearss and Thomas Camis as inventors, having Ser. No. 09/348,650, and incorporated herein by reference.




Referring to

FIG. 4

, components of control circuitry


30


are illustrated. The depicted embodiment of control circuitry


30


includes conditioning circuitry


70


, a system controller


72


, a memory


73


, a fuser controller


74


and a transfer bias controller


76


. Control circuitry


30


can also include other circuitry, such as analog power circuits (not shown).




In the depicted arrangement, conditioning circuitry


70


is coupled with sensor


22


, fuser controller


74


is coupled with fusing roller


66


and transfer bias controller


76


is coupled with transfer roller


54


(sensor


22


, fusing roller


66


and transfer roller


54


are shown in FIG.


2


).




System controller


72


comprises a digital microprocessor or microcontroller to implement print engine control operations in the described embodiment. System controller


72


is configured to execute a set of instructions provided as software or firmware of control circuitry


30


. Fuser controller


74


operates to control fusing roller


66


and transfer bias controller


76


operates to control transfer roller


54


.




Transfer roller


54


operates to attract developing material


61


from imaging roller


52


to media sheet


18


according to an imaging parameter. An exemplary imaging parameter is a bias voltage applied to transfer roller


66


. The imaging parameter may be adjusted to provide optimized printing or other image creation regardless of the type of media being printed upon in accordance with one aspect of the present invention.




Sensor


22


is provided in the described embodiment to monitor the media for controlling imager


24


. More specifically, sensor


22


is configured to determine or monitor qualitative and/or quantitative characteristics of the media and output a characteristic signal indicative of the qualitative and/or quantitative characteristics to conditioning circuitry


70


. Control circuitry


30


receives characteristic signals generated from sensor


22


and controls adjustment of the imaging parameter of imager


24


responsive to the signals. In another embodiment, sensor


22


additionally monitors ambient conditions (e.g., temperature, humidity, etc.) and control circuitry


30


additionally controls adjustment of the imaging parameter responsive to the monitoring of ambient conditions.




As previously mentioned, sensor


22


applies characteristic signals to control circuitry


30


. Conditioning circuitry


70


of control circuitry


30


receives the outputted characteristic signals from sensor


22


and applies respective conditioned signals to system controller


72


. Exemplary conditioning circuitry


70


can include filtering circuitry to remove unwanted spikes, noise, etc.




Memory


73


stores a look-up table which includes a plurality of values which may be applied to fuser controller


74


and transfer bias controller


76


to control fusing and transfer operations, respectively. As described further below, system controller


72


generates indices responsive to characteristic signals outputted from sensor


22


to index the look-up table stored within memory


73


. The look-up table values may be empirically derived to produce optimum settings for transfer bias controller


76


using media of known parameters and having known qualitative and quantitative characteristics. Thereafter, such look-up table values are accessed in real-time responsive to the monitoring of media using sensor


22


to provide optimized printing or other image formation within image forming device


10


.




System controller


72


applies control signals to transfer bias controller


76


responsive to the look-up table values. The look-up table values can comprise voltage requirements for transfer roller


54


to provide a desired bias. Transfer bias controller


76


applies the voltage requirements to transfer roller


54


responsive to the characteristic signals. Thereafter, the appropriate imaging parameter (e.g., bias voltage) of imager


24


is adjusted responsive to control signals received from, control circuitry


30


.




Referring to

FIG. 5

, transfer operations of developing material


61


from imaging roller


52


to media sheet


18


occur within transfer nip


62


.

FIG. 5

illustrates media sheet


18


intermediate imaging roller


52


and transfer roller


54


within transfer nip


62


. Imaging roller


52


is coupled with a ground node and thus is provided at a reference voltage condition. A positive voltage source


53


is coupled with transfer roller


54


as illustrated. Positive voltage source


53


is implemented within control circuitry


30


in one embodiment. Transfer bias controller


76


is configured to adjust the voltage bias applied to transfer roller


54


to provide optimized transfer of developing material


61


responsive to characteristic signals from sensor


22


.




An electrical field is generated intermediate imaging roller


52


and transfer roller


54


due to the voltage potential intermediate imaging roller


52


and transfer roller


54


. The generated electrical field tends to attract developing material


61


from imaging roller


52


toward transfer roller


54


and upon media sheet


18


within transfer nip


62


.




The toner transfer fields generated within transfer nip


62


are dependent to some degree upon the capacitance of media sheet


18


. Accordingly, in one aspect of the invention, sensor


22


is provided to monitor media being utilized and to generate a signal indicative of the monitoring. Thereafter, the transfer bias voltage applied to transfer roller


54


may be varied to provide optimum transfer levels for given media types. Such provides higher transfer efficiencies of developing material


61


from imaging roller


52


to media sheet


18


. Further, optimization of the transfer fields also serves to retain unwanted debris, such as CaCO


3


and talc (magnesium silicates), upon media sheet


18


rather than having the debris accumulate upon imaging roller


52


or the fuser film surface.




Referring to

FIG. 6

, one configuration of sensor


22


is illustrated. The depicted sensor


22


includes a first capacitor


80


and a second capacitor


82


. Sensor


22


is located along media path


32


as shown in FIG.


2


. Media sheet


18


is illustrated with respect to sensor


22


in FIG.


6


.




Capacitor


80


is formed by a fixed electrode


84


and a moveable electrode


86


. The electrical capacitance of capacitor


80


is determined by the electrode area, the thickness of media sheet


18


and the dielectric constant of the media. The dielectric thickness of the media may be derived from a measurement of the capacitance of capacitor


80


.




The dielectric thickness of media sheet


18


may be represented by D


media


and is equal to the permativity of free space constant ε


0


divided by the capacitance per unit area (D


media





0


/C


media


/A


electrodes


) being measured by sensor


22


. More specifically, C


media


is the capacitance of capacitor


80


and A


electrodes


is the area of the electrodes of capacitor


80


. Appropriate adjustments to the transfer electrical bias generated by voltage source


53


can be made based upon the changes in capacitance per unit area measured by capacitor


80


of sensor


22


.




It is preferred to maintain the electrical field induced to developing material


61


at a relatively constant value. The electrical field induced by the application of the voltage bias to transfer roller


54


may be represented by the following equation:







E
toner

=



(

1
/

k
t


)



[


V
transfer

-


(


pL
t

/

ε
0


)



(



D
t

/
2

+

D
opc


)


-

V
opc


]




D
opc

+

D
t

+

D
air

+

D
media













In the above equation, k


t


is the dielectric constant of the toner, V


transfer


is the voltage bias supply to transfer roller


54


using source


53


, p is the volume charge density of the toner, L


t


is the physical thickness of the toner, D


t


is the dielectric thickness of the toner, D


opc


is the dielectric thickness of imaging roller


52


, V


opc


is the voltage potential of imaging roller


52


, D


air


is the dielectric thickness of air and D


media


is the dielectric thickness of media sheet


18


as determined using measurements from capacitor


80


of sensor


22


according to one aspect of the invention.




In the exemplary embodiment described herein, the dielectric thickness of the media can be determined utilizing the measured electrical capacitance of media sheet


18


using capacitor


80


of sensor


22


. Accordingly, approximate voltage biases of source


53


for providing desired transfer fields can be determined using the dielectric thickness of the media and the above equation. Further, empirically derived voltage bias values can be determined using media having known parameters within image forming device


10


. Such empirical voltage bias values can be provided within the look-up table stored within memory


73


and subsequently accessed by system controller


72


responsive to the monitoring of media sheet


18


using capacitor


80


of sensor


22


.




The physical thickness of media sheet


18


is determined using capacitor


82


. Second capacitor


82


is formed by a moveable electrode


88


, air gap


90


and fixed electrode


92


. The capacitance of capacitor


82


is determined by the electrode area, air gap


90


and the dielectric constant of air (typically stable at 1.0). Air gap


90


is a function of the thickness of media sheet


18


inasmuch as moveable electrode


88


adjusts to the height of media sheet


18


. Thus, the physical thickness of media sheet


18


may be derived from a measurement of second capacitor


82


. The physical thickness measurement of media sheet


18


may be utilized to adjust the transfer electrical bias as described below.




Empirically derived voltage bias values can be determined corresponding to the physical thicknesses of the media. Such values can be stored within memory


73


and subsequently accessed by system controller


72


responsive to the monitoring of media sheet


18


using capacitor


82


of sensor


22


. One or both of the parameters determined by respective capacitors


80


,


82


may be utilized to provide desired transfer fields. It is preferred to use measurements from both capacitors


80


,


82


to control the transfer voltage bias.




Referring to

FIG. 7

, an exemplary circuit


81


is illustrated for measuring the capacitance of first capacitor


80


or second capacitor


82


. The depicted circuit


81


is a dual-slope integrator circuit. Circuit


81


includes plural amplifiers


83


,


85


configured as shown. Capacitor


87


is the capacitor-under-test and is used as a timing element in circuit


81


. Circuit


81


creates a square-wave signal at output


89


whose frequency is determined by the capacitance of capacitor-under-test


87


.




First capacitor


80


and second capacitor


82


can be individually provided as capacitor-under-test


87


to provide monitoring thereof. Plural circuits


81


can be provided to provide simultaneous monitoring of capacitors


80


,


82


. Alternatively, electrodes


86


,


88


could be combined into a single electrode. Circuit


81


could utilize a switch (not shown) to selectively provide one of capacitor


80


and capacitor


82


into circuit


81


. The capacitance of capacitors


80


,


82


could thereafter be measured sequentially. The measured capacitance represented by a signal at output


89


is applied to control circuitry


30


.




Referring to

FIG. 8

, operations for controlling an imaging parameter of imager


24


are described. The imaging parameter is controlled responsive to the monitoring of qualitative and/or quantitative characteristics of the media in accordance with one aspect of the present invention. Initially, sensor signals from sensor


22


corresponding to measured capacitance values of capacitors


80


,


82


are obtained as represented by step


93


. The sensor signals correspond to the dielectric thickness of the media and the physical thickness of the media.




Signals of varying frequency are generated responsive to changes in capacitance of capacitors


80


,


82


. Capacitors


80


,


82


can be coupled with conditioning circuitry


70


to provide appropriate conditioning for utilization within transfer bias controller


76


at step


94


. Exemplary conditioning includes filtering to remove extraneous spikes, as well as changing the format of the outputted signals. For example, varying capacitance values can be converted to varying frequency value signals within conditioning circuitry


70


comprising circuit


81


.




Thereafter, digital words are generated corresponding to the conditioned signals in step


95


. In one configuration, system controller


72


includes timer/counter circuitry (not shown) configured to generate digital words responsive to conditioned signals from circuitry


70


. Such circuitry converts frequency varying signals into respective digital words in the described embodiment.




System controller


72


generates table indices from the digital words at step


96


. Responsive to the generation of the table indices, look-up table values can be retrieved from memory


73


at step


97


. The values can be empirically derived look-up table values for providing optimum transfer bias settings to transfer bias controller


76


responsive to the digital words and table indices. At step


98


, the determined look-up table values are provided to transfer bias controller


76


to control imager


24


.




Referring to

FIG. 9

, a graphical representation of effects of media dielectric thickness upon electrical fields induced within developing material


61


within transfer nip


62


is illustrated. Plural lines


100


,


102


,


104


are illustrated upon the depicted graph. Line


100


corresponds to a transfer bias applied to transfer roller


54


of 1,000 Volts. Line


102


corresponds to a transfer bias of 1,500 Volts. Line


104


corresponds to a transfer bias of 2,000 Volts.




As illustrated, the transfer bias can be adjusted to provide a substantially constant induced electrical field upon developing material


61


as represented by line


106


. As the media dielectric thickness increases due to a given type media, the transfer bias voltage applied to transfer roller


54


can be increased to maintain the induced electrical field at a substantially constant value. Voltage settings of 1,000, 1,500 and 2,000 Volts provide a toner transfer field strength of about 12 Volts/micron for corresponding media dielectric thicknesses of 12 microns, 26 microns and 42 microns, respectively.




In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.



Claims
  • 1. An image forming device comprising:a housing including a media path; an input device configured to receive image data; a sensor positioned adjacent the media path and configured to monitor a qualitative characteristic of media within the media path and to generate a signal responsive to the monitoring; and an imager positioned adjacent the media path and configured to provide developing material corresponding to the image data upon the media according to an imaging parameter and to adjust the imaging parameter responsive to the signal.
  • 2. The image forming device according to claim 1 wherein the sensor is configured to monitor the qualitative characteristic comprising dielectric thickness of the media.
  • 3. The image forming device according to claim 1 wherein the sensor is configured to monitor a quantitative characteristic of the media.
  • 4. The image forming device according to claim 1 wherein the sensor is configured to monitor the media while the media is moving within the media path.
  • 5. The image forming device according to claim 1 wherein the sensor is configured to monitor the qualitative characteristic comprising dielectric thickness of the media while the media is moving within the media path.
  • 6. The image forming device according to claim 1 wherein the imager includes:an imaging roller positioned adjacent the media path and configured to receive the developing material; and a transfer roller adjacent the imaging roller and positioned to receive media between the imaging roller and the transfer roller; and the image forming device further comprises: a voltage source configured to apply the imaging parameter comprising a bias voltage to the transfer roller to attract the developing material from the imaging roller to the media; and a controller coupled with the sensor and configured to control the bias voltage applied by the voltage source responsive to the signal.
  • 7. The image forming device according to claim 1 wherein the sensor comprises a capacitor.
  • 8. An imaging assembly of an image forming device comprising:a sensor configured to monitor a qualitative characteristic of media within a media path of an image forming device and to generate a signal responsive to the monitoring; a controller coupled with the sensor and configured to receive the signal and to adjust an imaging parameter responsive to the signal; and an imager positioned adjacent the media path and coupled with the controller and configured to provide developing material upon the media according to the imaging parameter.
  • 9. The imaging assembly according to claim 8 wherein the sensor is configured to monitor the qualitative characteristic comprising dielectric thickness of the media.
  • 10. The imaging assembly according to claim 8 wherein the sensor is configured to monitor a quantitative characteristic of the media.
  • 11. The imaging assembly according to claim 8 wherein the sensor is configured to monitor the media while the media is moving within the media path.
  • 12. The imaging assembly according to claim 8 wherein the sensor is configured to monitor the qualitative characteristic comprising dielectric thickness of the media while the media is moving within the media path.
  • 13. The imaging assembly according to claim 8 wherein the sensor comprises a capacitor.
  • 14. A method of forming an image upon media comprising:providing an image forming device; providing image data; transferring developing material corresponding to the image data to media according to an imaging parameter; monitoring a qualitative characteristic of the media; and adjusting the imaging parameter responsive to the monitoring.
  • 15. The method according to claim 14 wherein the monitoring comprises monitoring the qualitative characteristic comprising dielectric thickness of the media.
  • 16. The method according to claim 14 wherein the monitoring further comprises monitoring a quantitative characteristic of the media.
  • 17. The method according to claim 14 wherein the monitoring comprises monitoring the media while the media is moving within the media path.
  • 18. The method according to claim 14 wherein the monitoring comprises monitoring the qualitative characteristic comprising dielectric thickness of the media while the media is moving within the media path.
  • 19. The method according to claim 14 wherein the transferring comprises transferring according to the imaging parameter comprising a voltage bias to attract the developing material of the image to the media; and the adjusting comprises adjusting the voltage bias.
  • 20. The method according to claim 14 wherein the monitoring comprises monitoring using a capacitor.
  • 21. An imaging forming device comprising:a housing configured to guide media along a media path; an input device configured to receive an image; a sensor adjacent the media path and configured to monitor the media and to generate a signal responsive to the monitoring, wherein the sensor comprises: a first capacitor having plural conductive plates positioned adjacent opposing sides of the media path; and a second capacitor having a fixed conductive plate and a moveable conductive plate positioned adjacent one side of the media path; and an imager adjacent the media path and configured to provide developing material corresponding to the image upon the media according to an imaging parameter and to adjust the imaging parameter responsive to the signal.
  • 22. An imaging assembly of an image forming device comprising:a sensor configured to monitor media traveling along a media path of an image forming device and to generate a signal responsive of the monitoring, wherein the sensor comprises: a first capacitor having plural conductive plates positioned adjacent opposing sides of the media path; and a second capacitor having a fixed conductive plate and a moveable conductive plate positioned adjacent one side of the media path; a controller coupled with the sensor and configured to receive the signal and to adjust an imaging parameter responsive to the signal; and an imager adjacent the media path and coupled with the controller and configured to provide developing material upon the media according to the imaging parameter.
  • 23. A method of forming an image upon media comprising:providing an image forming device; providing an image; transferring developing material corresponding to the image to media according to an imaging parameter; monitoring the media comprising: passing the media intermediate opposing conductive plates of a first capacitor; and passing the media adjacent one moveable conductive plate of a second capacitor; and adjusting the imaging parameter responsive to the monitoring.
RELATED PATENT DATA

This patent resulted from a continuation application of prior application Ser. No. 09/348,149, filed on Jul. 6, 1999, now U.S. Pat. No. 6,157,793, entitled “Image Forming Devices and Sensors Configured to Monitor Media, and Methods of Forming an Image Upon Media”.

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Continuations (1)
Number Date Country
Parent 09/348149 Jul 1999 US
Child 09/659655 US