Patent Grant
8985729
The present application is related to U.S. patent application 61/890,510, filed Oct. 14, 2013 and titled, “Method and Apparatus for Automatic Recovery Within an Imaging Device,” the content of which is hereby incorporated by reference herein in its entirety.
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1. Field of the Invention
The present disclosure relates generally to a method and a system for feeding a media sheet through an image forming device and, more particularly, to a method and system for performing imaging operations on the media sheets during a timing based malfunction.
2. Description of the Related Art
A printing device, such as an electrophotographic printer or an inkjet printer, for example, typically includes a media sheet feed system for sequentially transporting sheets of media from a media input tray to a transfer location for transferring a toner image thereto and subsequently to an output area which the media sheets may be accessed by a user.
Manufacturers of printing devices are continually challenged to improve printing device performance. One way in which improvement is sought is to achieve higher throughput rates. To deliver higher throughput, there is a greater chance of encountering a timing related issue. For example, a media sheet may reach a predetermined location upstream of the imaging device's transfer nip where a toner image is transferred thereto, prior to the printing device's print engine being ready for the toner image transfer. This could be due to the print engine minor motor taking too long to settle to its imaging speed, the laser servo process taking too long to finish, or the media sheet appearing at the predetermined location earlier than expected. When this situation occurs in current and/or prior machines, an error message is posted at the user display panel and the user of the printing device is forced to intervene and handle the error condition. Typically when these types of errors occur there is no damage to the media sheet and it is not a real jam condition in the traditional sense in that the media sheet is not unable to be transported along the printing device's media path.
Another timing related issue stems from a narrowing of the interpage gap to increase throughput. When the gap between sheets of media was too narrow or even undetectable, prior printing devices posted a paper jam, stopped the printing operation and required the user to take various remedial steps, such as opening covers, removing supplies and clearing sheets of media.
According to an example embodiment, there is shown an imaging apparatus having a media input tray, a print engine, an image transfer nip coupled to the print engine for transferring a toner image to sheet of media, an output area for maintaining imaged media sheets, a media path for transporting the media sheets from the media input tray through the image transfer nip and subsequently to the output area, and a plurality of path media sensors positioned along the media path between the media input tray and the output area. A controller executes a method for transferring a plurality of images to a plurality of media sheets, including transporting a first media sheet from the media input tray towards the transfer nip and determining, when the first media sheet reaches a predetermined point in the media path, whether the print engine is ready to transfer a first image of the plurality of images to the media sheet at the transfer nip. Upon a determination that the print engine is not ready, the method includes transporting the first media sheet through the transfer nip without transferring the first image thereto, until the first media sheet is placed in the output area, transporting a second media sheet to the transfer nip, transferring the first image to the second media sheet and transporting the second media sheet to the output area. In this way, a print operation is performed despite the occurrence of the timing based error condition.
In another example embodiment, the method addresses the situation in which the gap between successive sheets in the media path is small and tiny, which is smaller than small. In an example embodiment, if the gap is deemed to be small but not tiny, both media sheets are printed, either after predetermined timeout periods in which a leading or trailing edge of a media sheet is not detected or after predetermined predicted times which are based on locations where the sheet's edges are believed to exist. For tiny gaps, the downstream media sheet is printed and the upstream media sheet is flushed from the imaging apparatus without being imaged, with a further upstream media sheet being printed with the image originally intended for the flushed sheet.
The above-mentioned and other features and advantages of the various embodiments, and the manner of attaining them, will become more apparent and will be better understood by reference to the accompanying drawings.
The following description and drawings illustrate embodiments sufficiently to enable those skilled in the art to practice the present disclosure. It is to be understood that the disclosure is not limited to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways. For example, other embodiments may incorporate structural, chronological, electrical, process, and other changes. Examples merely typify possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in or substituted for those of others. The scope of the application encompasses the appended claims and all available equivalents. The following description is, therefore, not to be taken in a limiting sense and the scope of the present invention is defined by the appended claims.
Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted,” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. In addition, the terms “connected” and “coupled” and variations thereof are not restricted to physical or mechanical connections or couplings.
Spatially relative terms such as “top”, “bottom”, “front”, “back”, “rear” and “side”, “above”, “under”, “below”, “lower”, “over”, “upper”, and the like, are used for ease of description to explain the positioning of one element relative to a second element. These terms are generally used in reference to the position of an element in its intended working position within an image forming device. Further, terms such as “first”, “second”, and the like, are used to describe various elements, regions, sections, etc. and are not intended to be limiting. The term “image” as used herein encompasses any printed or digital form of text, graphic, or combination thereof. Like terms refer to like elements throughout the description.
Referring now to the drawings and particularly to
A user interface 17, such as a graphical user interface, is provided on imaging apparatus 10 for receiving user input concerning operations performed or to be performed by imaging apparatus 10, and for providing to the user information concerning the same. User interface 17 may include a display panel, which may be a touch screen display in which user input may be provided by the user touching or otherwise making contact with graphic user icons in the display panel. The display panel of user interface 60 may be sized for providing graphic and text images that allow for convenient communication of information between imaging apparatus 10 and the user. In addition or in the alternative, user interface 17 may include a plurality of push buttons or keys in addition to the display panel.
With continued reference to
Each imaging unit 22 includes a charging roll 26, a PC drum 24 and a cleaning blade (not shown). Charging roll 26 forms a nip with a corresponding PC drum 24 and charges the surface of PC drum 24 to a specified voltage. A laser beam from a printhead 21 is directed to the surface of PC drum 24 and discharges those areas it contacts to form a latent image. The developer roll of imaging unit 22 also forms a nip with PC drum 24 and transfers toner thereto to form a toner image. The toner is attracted to the areas of the PC drum 24 surface discharged by the laser beam. The cleaning blade then removes any remaining particles of toner from the PC drum 24 after the toner image is transferred to intermediate transfer mechanism (ITM) 30.
While an electrophotographic printing apparatus is illustrated in imaging apparatus 10, any of a variety of different types of printing mechanisms including dye-sublimation, dot-matrix, or ink-jet printing apparatuses may be used.
In the embodiment shown, ITM 30 is disposed adjacent to each of the imaging stations 18. In this embodiment, ITM 30 is formed as an endless belt trained about a series of rollers and opposed rollers. During image forming operations, ITM 30 moves past each of imaging stations 18 (in a counter-clockwise direction as viewed in
After receiving the toner images, the media sheets are moved further along the media path 36, indicated by the dashed line in
In the embodiment illustrated, imaging apparatus 10 is a color laser printer. In another embodiment, imaging apparatus 10 is a mono printer comprising a single toner cartridge 20 and a single imaging unit 22 for forming toner images in a single color. In another embodiment, imaging apparatus 10 is a direct transfer device that transfers the toner images from the one or more PC drums 24 directly to the media sheet. As used herein, the term media sheet is meant to encompass not only paper but also labels, envelopes, fabrics, photographic paper or any other desired substrate that can receive a toner image.
Imaging apparatus 10 further includes a controller 44 that controls the functioning of imaging apparatus 10 and the various components therein such as media feed motors, media sensors, media edge detectors, position detectors, print engines, fusers, etc. Controller 44 oversees the functioning of imaging apparatus 10 including movement of the media along media path 36 via opposed feed and exit rolls, imaging station(s) 18, ITM 30, printheads 21, and user interface 17.
It should be realized that for the various opposed rolls, such as exit rolls 40, feed rolls, transfer rolls, etc., one roll is a driven roll and the other is an idler roll. The driven roll is in operable communication with controller 44. Unless otherwise stated, references to these opposed rolls include both the driven roll and idler roll.
Controller 44 may include a processor unit and an associated memory, and may be formed as one or more Application Specific Integrated Circuits (ASICs). Memory 134 may be any volatile or non-volatile memory of combination thereof such as, for example, to random access memory (RAM), read only memory (ROM), flash memory and/or non-volatile RAM (NVRAM). Alternatively, the memory 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 44. The user interface 17 may include firmware maintained in memory within housing 12 which may be performed by the processor of controller 44 or another processing element.
Mounted adjacent to media path 36 are a plurality of media sensors that are used to detect the leading and trailing edges of a media sheet as it is being transported along media path 36. Media sensor 48 is shown positioned upstream of transfer nip 34. Media sensor 40 is shown positioned downstream of transfer nip 34. It is understood that imaging apparatus 10 may include addition media sensors disposed along media path 36, and the particular location of each media sensor, including media sensors 48 and 50, may vary and depend upon a number of factors. Media sensors 48 and 50 may be any type of sensor that is capable of detecting the leading and trailing edges of a media sheet. For example, each media sensor 48 and 50 may be a photo-interrupter or mechanical flag sensor.
Controller 44, when executing firmware code during a print operation, determines whether there exists a timing problem and take remedial action to complete the print operation without requiring user intervention. In this way, imaging apparatus 100 provides more robust printing performance.
For instance, the timing problem may be a media sheet arriving at a predetermined location upstream of transfer nip 34 along media path 36 prior to printheads 21 being ready to create a latent image on PC drums 24. This may be due to the motor operating printheads 21 not being locked to the desired speed for rotating the mirror for sweeping the scan lines across PC drums 24. The timing problem may also be due to, for example, the laser servo process taking too long to complete, and/or the media sheet arriving earlier than expected at the predetermined location, which may be at media sensor 48. Instead of posting an error and/or entering an error state that would require user intervention before resuming normal operation, as with prior printing devices, imaging apparatus 10 generally transports the affected media sheet(s) along media path 36 without transferring a toner image thereto at transfer nip 34.
The method of operating imaging apparatus 10 when a timing problem arises will be described with respect to
In the event the process referred to as Process 1 is selected, media sheets are stopped from entering media path 36 at 308. In addition, data relating to the media sheets that were in media path 36 at the time of the detection of the error condition but had not yet been imaged, that would be necessary in order for the corresponding images to be printed, are stored in memory and/or recorded at 310. The media sheets that were in media path 36 at the time of the detection of the error condition, both sheets that were imaged and sheets that were not yet imaged, are flushed from imaging apparatus 10 at 312. Following the media sheets being flushed, and upon a determination that printheads 21 are ready to begin imaging, the imaging system of imaging apparatus 10 resumes at 314. Media sheets are picked from media input tray 16 and transported along media path 36 towards transfer nip 34 at 316. Thereafter, normal printing is resumed with the media sheets transported at 316 replacing the unprinted sheets that were flushed from imaging apparatus 10 at 312.
The second process, Process 2, generally involves moving the sheet corresponding to the printing error to output area 42 and imaging with media sheets upstream therefrom. Specifically, upon Process 2 being selected at 306, print engine code is set at 320 to launch an additional sheet of media. The media sheet S corresponding to the error condition continues being transported at 322 until its trailing edge (TE) has passed transfer nip 34. Thereafter, the to-be-printed images of the print job are reassigned to the media sheets upstream of media sheet S at 324. Specifically, the image I that was initially to be printed on media sheet S is reassigned to be printed on media sheet S+1, which is the media sheet immediately upstream of media sheet S, either in media path 36 or the top of the stack of sheets in media input tray 16. Image I+1, which was to be printed on media sheet S+1, is reassigned to media sheet S+2, the media sheet immediately upstream of media sheet S+1, which may be at or near the top of the media stack in media input tray 16. The reassignment proceeds in this way until each image to be printed has been reassigned to a media sheet to immediately upstream of the media sheet to which it had been previously assigned. The imaging system of imaging apparatus 10 is resumed at 326 with a resumption of normal printing. Media sheets S+1, S+2, . . . are transported along media path 36 from media input tray 16 at 328, whereupon the sheets are imaged at second transfer nip 34, fused at fuser 38 and placed in output area 42.
As discussed above, controller 44 causes processes illustrated in
Small gaps are gaps between successive media sheets in media path 36 is a gap in which both the TE of a media sheet S and the leading edge (LE) of media sheet S+1 immediately upstream of media sheet S in media path 36 are detected at an input media sensor, such as media sensor 48. With such a small gap, it is possible that no edge, i.e., no gap is detected at an exit sensor, such as media sensor 50 or a sensor located further downstream in media path 36.
In one example embodiment, either of two approaches may be used to address the condition in which a small gap exists at an input sensor, such as media sensor 48. Both approaches are illustrated in
In the event, however, that the captured gap is less than or equal to the predetermined gap value at 404, then sheet A is marked with a TE gap tag and sheet B is marked with a LE gap tag at 410. In one of the two approaches identified above, if the TE of sheet A is not detected at media sensor 50 or some other exit sensor in media path 36 during a predetermined timeout period at 412, because sheet A had been marked with a TE tag at 410, it is assumed that the previously detected gap between sheets A and B had closed. In response, controller 44 causes sheet A to be printed at 414. Similarly, if detecting the LE of sheet B at media sensor 50 (or some other exit sensor in media path 36) fails during a predetermined timeout period at 416 while waiting for media sensor 50 to be cleared (from sheet A passing completely through it), because sheet B had been previously marked with a LE tag it is assumed that the previously detected gap between sheets A and B had closed and controller 44 causes sheet B to be printed at 418. The printing on sheets A and B are performed instead of posting a media jam so that there is no interruption with the print operation.
In the second of two approaches, if the measured interpage gap at media sensor 48 is less than the predetermined gap value, it is assumed that the gap will be closed at media sensor 50 (or some other exit sensor), and printing of sheets A and B are set to occur at times sheet A and B are predicted to pass through transfer nip 34. Specifically, following sheets A and B being marked with TE and LE gap tags, respectively, at 410, predicted time delays are assigned to sheets A and B at 420. Thereafter, sheet A is printed at the completion of its predicted time delay at 422 and sheet B is printed at the completion of its predicted time delay at 424. Like in the first approach, in the second approach sheets A and B are printed without posting a media jam so that there is no interruption with the print operation.
Referring to
The foregoing description of several embodiments has been presented for purposes of illustration. It is not intended to be exhaustive or to limit the invention to the precise designs disclosed, and obviously many modifications and variations may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. It is intended that the scope of the invention be defined by the claims appended hereto.
| Number | Name | Date | Kind |
|---|---|---|---|
| 6813451 | Wibbels | Nov 2004 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| 61890510 | Oct 2013 | US |
