Image forming devices are comprised of a multitude of various electrical, mechanical, and optical devices. It is typically the case that all of the components of the image forming device must be properly installed for the image forming device to function properly. There are some exceptions. For instance, in an image forming device having a plurality of media trays, it may be possible for the image forming device to function properly if one or more trays are removed from the image forming device if there is at least one tray with a sufficient amount of media installed in the image forming device.
Similarly, it may be possible for color image forming devices to operate even though one or more toner cartridges is empty or completely removed. As an example, some color electrophotographic imaging devices have four developer cartridges, each cartridge containing a different color toner and perhaps other developer components such as a developer roll and a photoconductive member. A common color scheme found in color image forming devices uses cyan, magenta, yellow, and black developer cartridges. In color image forming devices such as these, it may be possible to operate in a black-only mode if one or more of the non-black developer cartridges is absent from the color image forming device. It is useful in such a scenario to detect the presence or absence of each of the toner cartridges to determine the allowable operating modes (e.g., black-only, full color, or partial color). Some common techniques for detecting the presence or absence of components include mechanical switches, optical sensors, and electrical or electromagnetic devices such as proximity sensors that use an RF or other distinctive signature. However, there are instances where the use of these types of detectors is impractical because of cost, space, or reliability concerns.
Embodiments of the present invention are directed to sensing the presence or absence of components of one or more removable image forming units in an image forming device. An image forming unit may comprise a removable component. An associated power supply is adapted to apply an input signal to the removable component. Sense circuitry coupled to the removable component of the one or more image forming units may sense the application of the input signal when the removable component is properly installed. The removable cartridge may comprise a photoconductive member, a transfer roller, a developer roller, or some combination of these imaging components. Further, these imaging components may be disposed in separate customer replaceable units. The image forming device may also include control circuitry that halts image formation if the sense circuitry fails to sense the presence of necessary image forming unit components. Similarly the control circuitry may halt image formation if the sense circuitry senses the presence of image formation unit components not necessary for a current mode of operation.
The image forming device may be configured to operate in a black-only mode using a single image forming unit. The image forming device may also be a color image forming device with multiple image forming units corresponding to different colors. The controller may therefore control image formation in different color modes by sensing the presence or absence of necessary and unnecessary components.
The present invention is directed to an apparatus and related method for determining the presence or absence of components in an image forming device 10, such as a printer of the type illustrated in
Media sheets are moved from the input and fed into a primary media path. One or more registration rollers 99 disposed along the media path aligns the print media and precisely controls its further movement along the media path. A media transport belt 20 forms a section of the media path for moving the media sheets past a plurality of image forming units 100. Color printers typically include four image forming units 100 for printing with cyan, magenta, yellow, and black toner to produce a four-color image on the media sheet.
An imaging device 22 forms a latent image on a photoconductive member 51 within the image forming units 100. At each image forming unit 100, the latent images are developed by a developer member 45 that supplies and transfers toner to the photoconductive member 51. The developed image, which is comprised at this point of loose, but electrostatically charged toner is then transferred to media sheets with the aid of a transfer roller 34. The media sheet with loose toner is then moved through a fuser 24 that adheres the toner to the media sheet. The sheet is then either forwarded through the output rollers 26 into an output tray 28, or the rollers 26 rotate in a reverse direction to move the media sheet to a duplex path 30. The duplex path 30 directs the inverted media sheet back through the image formation process for forming an image on a second side of the media sheet.
It is worth noting that other image forming devices may implement an indirect-transfer scheme whereby a developed image is initially transferred from the photoconductive surface 51 to an intermediate transfer mechanism substrate, such as a belt or a drum, before the image is subsequently transferred to a media sheet. The embodiments disclosed herein are applicable to these types of devices as well.
Further, as illustrated in
The PC unit 50 comprises the photoconductive member 51 and a charge roller 52. In one embodiment, the photoconductive member 51 is an aluminum hollow-core drum coated with one or more layers of light-sensitive organic photoconductive materials. A housing 56 forms the exterior of a portion of the photoconductor unit 50. The photoconductive member 51 is mounted protruding from the PC unit 50 to contact the developer member 45 at nip 46. Charge roller 52 is electrified to a predetermined bias by a high voltage power supply (HVPS) 60. The charge roller 52 applies an electrical charge to the surface of the photoconductive member 51. During image creation, selected portions of the surface of the photoconductive member 51 are exposed to optical energy, such as laser light, through aperture 48. Exposing areas of the photoconductive surface 51 in this manner creates a discharged latent image on the photoconductive member 51. That is, the latent image is discharged to a lower charge level than areas of the photoconductive member 51 that are not illuminated.
The developer member 45 and the toner thereon are charged to another bias level by the HVPS 60 that is advantageously set between the bias level of charge roller 52 and the discharged latent image. This charged toner is carried by the developer member 45 to the latent image formed on the surface of the photoconductive member 51. As a result of the imposed bias differences, the toner is attracted to the latent image and repelled from the remaining, higher charged portions of the photoconductive surface. At this point in the image creation process, the latent image is said to be developed.
The developed image is subsequently transferred to a media sheet being carried past the photoconductive member 51 by media transport belt 20. In the exemplary embodiment, a transfer roller 34 is disposed behind the transport belt 20 in a position to impart a contact pressure at the transfer nip. In addition, the transfer roller 34 is advantageously charged, typically to a polarity that is opposite the charged toner and charged photoconductive member 51 to promote the transfer of the developed image to the media sheet. The polarity of the transfer roller 34 is also switched periodically, typically between print jobs, to clean the transfer roller 34. This change in polarity induces the transfer of toner back towards the transport belt 20 and/or the photoconductive member 51, each of which has their own associated cleaning device (e.g., cleaner blade 53).
The cleaner blade 53 contacts the surface of the photoconductive member 51 to remove toner that remains on the photoconductive member 51 following transfer of the developed image to a media sheet passing between the photoconductive member 51 and the media transport belt 20. The residual toner is moved to a cleaner housing 62, where a waste toner auger 54 moves the waste toner out of the photoconductor unit 50 and towards a waste toner container (not shown), which may be disposed of once full.
In one embodiment, the charge roller 52, the developer member 45, and the photoconductive member 51 are all negatively biased. The transfer roller 34 is normally positively biased, except during cleaning procedures, when the polarity of the charge applied to the transfer roller 34 is temporarily switched to a negative value. Also, as discussed below, a negative pulse of the transfer roller 34 may advantageously be used to check for the presence or absence of the PC unit 50. Those skilled in the art will comprehend that an image forming unit 100 may implement polarities opposite from these.
Each developer unit 40 may include an associated sense device 36 for detecting the absence or presence of the developer unit 40 within the body 12 of the image forming device 10. The sense device 36 may be embodied as a mechanical, optical, or electrical sensor as are known in the art. However, sense device 36 may be specifically implemented as a signature button that is read by the image forming device 10. In other embodiments, the sense device 36 is identified using a corresponding sensor (not shown) located within the body 12 of the image forming device 10 that recognizes the presence or absence of the signature button.
Since the developer unit 40 is separable from the PC unit 50, sense device 36 does not indicate the presence or absence of the PC unit 50. However, the PC Sense circuit 38 shown in
Those skilled in the art will recognize that the equivalent circuit 66 shown in
The exemplary PC Sense circuit 38 generates a binary output signal PC_Sns in response to a detected input signal Vin. The controller 64 determines the presence or absence of the PC unit 50 based on the value of the binary output signal PC_Sns. During a steady-state condition, while both the bias Vcharge of charge roller 52 and the bias Vroller of transfer roller 34 are held at 0 volts, the input signal Vin is held at a high value of +5 volts by a low-voltage power source within the PC Sense circuit 38. If the bias Vcharge of charge roller 52 is kept at 0 volts and the bias Vroller of transfer roller 34 is switched on, the signal change is propagated through the transfer roller 34, through the photoconductive member 51 and to the input of the PC sense circuit 38. The signal waveforms depicted in
A similar change in voltage is passed along to the core of the photoconductive member 51 and, consequently, to the input Vin of the PC Sense circuit 38. For the period of time that the input signal Vin drops below a predetermined threshold, the exemplary PC Sense circuit 38 generates a high output signal PC_Sns, which the controller 64 detects as an indication that the PC unit 50 is properly installed in the image forming device 10. The same type of diagnostic check may be performed for each PC unit 50 in the image forming device. Similarly, the polarity of the PC_Sns output signal may be reversed in alternative embodiments.
One application of the exemplary method and device for determining the presence or absence of the PC unit 50 in the exemplary image forming unit 100 shown in
As shown in
Similarly, the controller 64 determines whether the PC units 50 for each color toner are present in the image forming unit (Step 610). In the exemplary embodiment, the presence or absence of the PC units 50 is determined using the PC sense circuitry 38 associated with each PC unit 50. If one or more PC units 50 are absent, the controller 64 generates an error signal and prompts the operator to install the missing PC unit(s) 50 (Step 612). If the controller 64 determines that all developer units 40 and PC units 50 are present, the image forming device 10 proceeds to generate full color images (Step 614). It is worth noting that the procedure outlined in
A similar procedure is outlined in
Specifically, the operator sets a black print mode (Step 700), typically via the user panel of the image forming device 10. The print mode may also be set using an associated driver on a host computer or other server. If necessary, such as during initial product setup, the operator installs the black developer units 40 and PC units 50 into the image forming device 10. Alternatively or additionally, the operator may be prompted to remove the non-black developer units 40 and PC units 50 (Step 702). Controller 64 within the image forming device 10 then determines whether the access door 14 is closed (Step 704). If the access door 14 is not properly closed, the operator may be prompted to take corrective action. If the access door 14 is closed, the controller 64 determines whether the black developer unit 40 is present in the image forming unit (Step 706). In the exemplary embodiment, the presence or absence of the black developer unit 40 is determined using the sense device 36 associated with the black developer unit 40. If the black developer unit 40 is not installed, the controller 64 generates an error signal and prompts the operator to install the missing developer unit 40 (Step 708).
Similarly, the controller 64 determines whether the black PC unit 50 is present in the image forming unit (Step 710). In the exemplary embodiment, the presence or absence of the black PC unit 50 is determined using the PC sense circuitry 38 associated with the black PC unit 50. If the black PC unit 50 is absent, the controller 64 generates an error signal and prompts the operator to install the missing PC unit 50 (Step 712).
The controller 64 then proceeds to determine whether the non-black (e.g., C, M, Y) developer units 40 are present in the image forming unit (Step 714). In the exemplary embodiment, the presence or absence of the non-black developer units 40 is determined using the sense device 36 associated with each non-black developer unit 40. If one or more non-black developer units 40 are installed, the controller 64 generates an error signal and prompts the operator to remove the installed non-black developer units 40 (Step 716).
Similarly, the controller 64 determines whether the non-black PC units 50 are present in the image forming unit (Step 718). In the exemplary embodiment, the presence or absence of the black PC units 50 is determined using the PC sense circuitry 38 associated with each non-black PC unit 50. If the non-black PC units 50 are present, the controller 64 generates an error signal and prompts the operator to remove the non-black PC unit(s) 50 (Step 720). If the controller 64 determines that the desired developer units 40 and PC units 50 are present, the image forming device 10 proceeds to generate black or grayscale images using black toner (Step 722).
The embodiments disclosed thus far have contemplated the use of a sense device 36 associated with each developer unit 40. However, the technique disclosed herein for detecting the presence or absence of the PC unit 50 may be equally applicable to the developer unit 40. For instance, referring to
Thus, the presence or absence of each of the removable components (e.g., developer unit 40, PC unit 50, transfer roller 34 and belt 20) can be verified using the HVPS 60 signal and PC Sense circuit 38. An exemplary approach is to transmit the characteristic HVPS 60 signal through two or more removable components to verify the existence of each component. The absence of a component in the detection path will create a large impedance and the PC Sense circuit 38 will not generate a detection signal (e.g., a high value for PC_Sns as shown in
The exemplary image forming unit 100 shown in
Those skilled in the art should also appreciate that the control circuitry associated with controller 64 shown in the Figures for implementing the present invention may comprise hardware, software, or any combination thereof. For example, circuitry for generating an error or interrupting image formation if a component is not detected may be a separate hardware circuit, or may be included as part of other processing hardware. More advantageously, however, the processing circuitry in these devices is at least partially implemented via stored computer program instructions for execution by one or more computer devices, such as microprocessors, Digital Signal Processors (DSPs), ASICs or other digital processing circuits included in the controller 64. The stored program instructions may be stored in electrical, magnetic, or optical memory devices, such ROM and RAM modules, flash memory, hard disk drives, magnetic disc drives, optical disc drives and other storage media known in the art.
The present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. For instance, whereas a single controller 64 and PC Sense circuit 38 is shown in
Number | Name | Date | Kind |
---|---|---|---|
5225870 | Tanimoto et al. | Jul 1993 | A |
5617188 | Inomata | Apr 1997 | A |
5862430 | Mitekura et al. | Jan 1999 | A |
5909603 | Suziki et al. | Jun 1999 | A |
6029018 | Rogers, IV et al. | Feb 2000 | A |
6029019 | Kawai | Feb 2000 | A |
6137966 | Uehara et al. | Oct 2000 | A |
6201935 | Terada et al. | Mar 2001 | B1 |
6226476 | Miyabe et al. | May 2001 | B1 |
6311025 | Nagata et al. | Oct 2001 | B1 |
6311026 | Higeta et al. | Oct 2001 | B1 |
6408142 | Takeuchi et al. | Jun 2002 | B1 |
6763198 | Matsumoto | Jul 2004 | B2 |
7092653 | Yoshizuka et al. | Aug 2006 | B2 |
20020191981 | Miyabe et al. | Dec 2002 | A1 |
20040008997 | Yoshimoto | Jan 2004 | A1 |
20040253008 | Chapman et al. | Dec 2004 | A1 |
20050105922 | Kawai | May 2005 | A1 |
Number | Date | Country |
---|---|---|
11-237814 | Aug 1999 | JP |
Number | Date | Country | |
---|---|---|---|
20060227359 A1 | Oct 2006 | US |