Hard imaging devices and hard imaging methods

Hard imaging devices and hard imaging methods are described. According to one embodiment, a hard imaging device includes an image engine configured to provide a marking agent upon media to form hard images, and a media sensing system configured to sense the media and to provide at least one signal comprising information indicative of a direction of grain of the media responsive to the sensing of the media, and processing circuitry configured to receive the at least one signal provided by the media sensing system and to control an operation of the hard imaging device using the information indicative of the direction of the grain of the media of the at least one signal.

FIELD OF THE DISCLOSURE

Aspects of the disclosure relate to hard imaging devices and hard imaging methods.

BACKGROUND OF THE DISCLOSURE

Paper grain may be defined as an anisotropic material property in paper due to a tendency for paper fiber orientation to align with a web processing direction during manufacture. In addition, residual stresses induced from the drying steps in processing also contribute to anisotropy. For example, in web machine processing of paper, fibers of paper sit upon a substrate such as a screen, additives are added and thereafter the fibers and additives are dried. The substrate may be removed and the structure of fibers which forms the paper may be wound onto rolls. In this illustrative process, strains are placed upon the paper in the web machine direction which tend to result in the fibers being aligned with the web machine direction as opposed to the cross web direction. As discussed below according to one embodiment, hard imaging methods and apparatus are described for determining a direction of the grain of the media.

SUMMARY

According to some aspects of the disclosure, hard imaging devices and hard imaging methods are described.

According to one aspect, a hard imaging device comprises an image engine configured to provide a marking agent upon media to form hard images, and a media sensing system configured to sense the media and to provide at least one signal comprising information indicative of a direction of grain of the media responsive to the sensing of the media, and processing circuitry configured to receive the at least one signal provided by the media sensing system and to control an operation of the hard imaging device using the information indicative of the direction of the grain of the media of the at least one signal.

According to another aspect, a hard imaging method comprises using a hard imaging device, forming hard images including providing a marking agent upon media, using the hard imaging device, determining a direction of grain of the media, and using the direction of the grain of the media, controlling an operation of the hard imaging device with respect to the forming hard images.

Other embodiments and aspects are described as is apparent from the following discussion.

DETAILED DESCRIPTION

Some embodiments of the present disclosure are described with respect to hard imaging (i.e., formation of images upon media such as paper or other suitable substrate). As discussed above, for some types of media (e.g., paper media), fibers of the media may be generally aligned in a common direction during manufacture of the media. However, depending upon how the media is cut, the long grain of the media may be aligned (i.e., parallel) with a process direction of the hard imaging device (e.g., the process direction is parallel with a direction of movement of media moving along a media path of the hard imaging device) or a scan direction of the hard imaging device (e.g., the scan direction is perpendicular to a direction of movement of media moving along the media path of the hard imaging device) in illustrative embodiments. As discussed below with respect to at least one embodiment, a direction of grain of media may be determined and operations of the hard imaging device performed with respect to hard imaging upon the media may be implemented and/or adjusted according to the direction of the grain of the media. In one embodiment, apparatus and methods are described which detect a direction of grain of media and the information regarding the direction of the grain may be used to control one or more operation of the hard imaging device with respect to the formation of hard images. Additional embodiments are described below.

Referring toFIG. 1, one embodiment of a hard imaging device10configured to form hard images upon media is depicted as a printer. Some illustrative configurations of device10implemented as a printer include laser, inkjet, impact and liquid ink based presses (e.g., Indigo press available from Hewlett-Packard Company) although other configurations are possible. Hard imaging device10may be arranged in other hard imaging configurations, such as a copier, facsimile, or multi-purpose peripheral, in other embodiments. Hard imaging device10includes a housing12and an input media tray14configured to store a supply a media16to be used for hard imaging in the depicted embodiment. Media16having hard images thereon produced by hard imaging device10is shown in an output tray18in the illustrated embodiment.

Referring toFIG. 2, components of one embodiment of hard imaging device10are shown. The depicted arrangement includes processing circuitry20, storage circuitry22, a display24, a media tray14, a media sensing system26and an image engine28which may be provided within housing12(FIG. 1) in one embodiment.

Media tray14is configured to hold a supply of one or more type of media16to be imaged upon. Media16may be pulled from the media tray14and travel along a media path19within housing12during hard imaging by device10. Media path19may correspond to a path which media16travels along within hard imaging device10from media tray14to image engine28and output tray18(FIG. 1) in one embodiment.

In one embodiment, processing circuitry20is arranged to process data, control data access and storage, issue commands, and control other desired operations of hard imaging device10. Processing circuitry20may access image data corresponding to content of images to be hard imaged by device10and may control image engine28to form the images using the image data. Processing circuitry20may comprise circuitry configured to implement desired programming provided by appropriate media in at least one embodiment. For example, the processing circuitry20may be implemented as one or more of a processor and/or other structure configured to execute executable instructions including, for example, software and/or firmware instructions, and/or hardware circuitry. Exemplary embodiments of processing circuitry20include hardware logic, PGA, FPGA, ASIC, state machines, and/or other structures alone or in combination with a processor. These examples of processing circuitry20are for illustration and other configurations are possible.

The storage circuitry22is configured to store programming such as executable code or instructions (e.g., software and/or firmware), electronic data, databases, or other digital information and may include processor-usable media. Processor-usable media may be embodied in any computer program product(s) or article of manufacture(s) which can contain, store, or maintain programming, data and/or digital information for use by or in connection with an instruction execution system including processing circuitry20in the exemplary embodiment. For example, exemplary processor-usable media may include any one of physical media such as electronic, magnetic, optical, electromagnetic, infrared or semiconductor media. Some more specific examples of processor-usable media include, but are not limited to, a portable magnetic computer diskette, such as a floppy diskette, zip disk, hard drive, random access memory, read only memory, flash memory, cache memory, and/or other configurations capable of storing programming, data, or other digital information.

At least some embodiments or aspects described herein may be implemented using programming stored within appropriate storage circuitry22described above and/or communicated via a network or other transmission media and configured to control appropriate processing circuitry20. For example, programming may be provided via appropriate media including, for example, embodied within articles of manufacture, embodied within a data signal (e.g., modulated carrier wave, data packets, digital representations, etc.) communicated via an appropriate transmission medium, such as a communication network (e.g., the Internet and/or a private network), wired electrical connection, optical connection and/or electromagnetic energy, for example, via a communications interface, or provided using other appropriate communication structure or medium. Exemplary programming including processor-usable code may be communicated as a data signal embodied in a carrier wave in but one example.

Display24is configured to depict information for observation by the user. For example, display24may generate human perceptible messages for communication to an operator in one embodiment.

Media sensing system26is configured to sense media16in one embodiment. In some embodiments, media sensing system26may be positioned at an appropriate location to sense media16within media tray14or at suitable locations along media path19. Media sensing system26may be positioned along media path19upstream of image engine28to provide information regarding the direction of grain of a sheet of media16prior to hard imaging upon the sheet of media16by image engine28in one embodiment. In another embodiment, a sheet of media16may be passed through device10(e.g., with or without imaging thereon) during calibration to determine the direction of the grain of media16. Different methods may be used for media sensing system26to sense media16in other embodiments.

Media sensing system26is configured in one embodiment to provide a signal indicative of a direction of grain (e.g., long grain direction) of the media16responsive to the sensing of the media16. The signal including information regarding the direction of the grain may be communicated to processing circuitry20which may control an operation of the hard imaging device10using the determined direction of the grain as described in further detail below.

Image engine28is configured to form hard images upon the media16in one embodiment. The formed hard images may include content of image data processed by processing circuitry20. Image engine28may provide a marking agent upon media16to form hard images in illustrative configurations. For example, in an ink jet arrangement of hard imaging device10, image engine28may provide a marking agent in the form of droplets of one or more color of ink upon media16to form hard images. In an electrophotographic arrangement of hard image device10, image engine28may provide a marking agent in the form of dry toner or liquid ink of one or more color upon media16. Other embodiments of image engine28are possible.

Referring toFIG. 3, one exemplary embodiment of a media sensing system26configured to sense media16(media16is not shown inFIG. 3) is shown. In one embodiment as mentioned above, media sensing system26is configured to sense and provide information indicative of a direction of grain of the media16. In the embodiment ofFIG. 3, media sensing system26is configured to monitor reflectivity of light from media16in a plurality of directions (e.g., process and scan directions which are parallel and perpendicular, respectively, to a direction of movement of media traveling along media path19in one example) to provide the information indicative of the direction of the grain. Media sensing system26is configured to provide signals comprising intensity information corresponding to reflected light in plural directions in the embodiment ofFIG. 3.

The media sensing system26includes a plurality of light sources30a,30b,30cand a light sensing device34in the depicted embodiment. Light sources30a,30b,30care configured to emit respective light beams32a,32b,32cand may be configured as light emitting diodes (LEDs) in one implementation. Although three light sources30a,30b,30care shown inFIG. 3, other numbers of light sources may be used in other configurations of media sensing system26. For example, in one alternative embodiment, one or more of the light sources30a,30b,30cmay be omitted.

The illustration ofFIG. 3is a plan view wherein the media sensing system26is positioned over a substrate40adjacent to media path19. A sheet of media may ride upon substrate40intermediate substrate40and media system26in one embodiment. Light sources30a,30b,30cmay be configured in one embodiment to emit respective light beams32a,32b,32cat relatively low angles with respect to a surface of the sheet of media (e.g., light sources30a,30b,30cmay all emit light beams32a,32b,32cat the same angle within a range of 0 to 45 degrees in one example). The downwardly emitted light beams32a,32b,32care reflected upwardly by the sheet of media and are received by light sensing device34such as a photodiode in one embodiment. Light sensing device34may be positioned at a central location of light sources30a,30b,30cand be arranged to sense light received in a direction substantially normal to the sheet of media16in one embodiment.

In one embodiment, substrate40is a material having reduced or minimal grain to reduce interference thereof with the readings of the media. For example, substrate40may be configured as a black sheet of plastic or polished stainless steel. An aperture42may be provided in substrate40and aligned opposite media sensing system26such that light passing through a sheet of media passes through the aperture42and is not reflected upwardly by substrate40which may otherwise interfere with readings by light sensing device34.

In the described embodiment, two light sources30a,30bare arranged in orthogonal process and scan directions and are configured to emit respective light beams32a,32bof substantially the same intensity in the process and scan directions of the media path19. Light sensing device34may generate respective signals corresponding to intensity of light received from light beams32a,32breflected by a sheet of media riding upon substrate40in the respective process and scan directions in one embodiment. The respective signals are indicative of the direction of the grain of media16and may be processed by processing circuitry20to determine the long grain and short grain directions of the sheet of media traveling along paper path19. A greater amount of light is reflected by a light beam parallel to the short grain direction of the media compared to an amount of light reflected by a light beam parallel to the long grain direction of the media. Accordingly, a signal generated by light sensing device34having the larger intensity responsive to one of light beams32a,32bwill indicate the short grain direction of the media parallel to the direction of the one of the light beams32a,32bin one embodiment.

As mentioned above, one or more of light sources30a,30b,30cmay be omitted. In one embodiment, light source30cis provided to enable verification of readings of light beams32a,32b. For example, output from light sensing device34responsive to light beam32cshould indicate an intensity value between intensity values resulting from light beams32a,32bto verify proper sensing operations of system26. In one embodiment, light sources30a,30b,30cmay be sequentially powered to enable light sensing device34to provide signals corresponding to light received from respective ones of the light sources30a,30b,30c. Other embodiments are possible and may, for example, include different orientations of the components of the media sensing system26and/or omission of light source32c.

In another embodiment, media sensing system26may include one light source and a plurality of light sensing devices. For example, the light sensing device34ofFIG. 3may be replaced by a light source and the light sources30a,30b,30cmay be replaced by respective light sensing devices. The light source of this embodiment may be configured to emit a light beam in a direction towards the media which is substantially normal to the surface of the media. Light sensing devices may be positioned and configured similarly to the arrangement of light sources30a,30b,30cto receive low angle light emitted by the light source and reflected in respective ones of the plural directions by a sheet of media in one embodiment. For example, two of the light sensing devices may be aligned with and configured to receive light reflected from the media in orthogonal directions corresponding to the process and scan directions and perhaps at least one additional intermediate direction (e.g., position corresponding to light source30c) as shown inFIG. 3for verification operations.

The above described embodiments describe arrangements of system26wherein light which was reflected from media16is used to determine the orientation of the grain of the media16due to texturing effects of the media16(i.e., corresponding to a bias in the orientation of the paper fibers) upon impinging light. In other embodiments, light sensing devices and light sources of the above-described illustrative arrangements may be provided at opposite sides of the media16to provide similar monitoring of the texturing effects of the media for determining the orientation of the grain by sensing light (e.g., collimated) passing through the media16. Other embodiments are possible.

Signals outputted by one or more of the light sensing devices34may be provided to processing circuitry20as mentioned above for processing. The above-described texturing effect can be measured by processing circuitry20using the signals outputted by media sensing system26and indicative of the intensity of light from a sheet of media16in orthogonal directions corresponding to the process direction and the scan direction. As mentioned above, light from a sheet of media16in a direction parallel to the short or cross grain direction has a greater intensity value compared with light from a sheet of media in a direction parallel to the long grain direction of the media16(i.e., the direction of the grain of the media16). In one embodiment, processing circuitry20may calculate a ratio of the signals corresponding to the orthogonal directions and determine the direction of the grain of the sheet of media.

Referring toFIG. 4, a graphical representation of intensity information of signals outputted from media sensing system26is shown for different types of media16. In the illustrated graph, intensity information is plotted against the y axis and time is plotted against the x axis for multipurpose media, recycled media, and photo media. In particular, line50corresponds to a long grain direction of multipurpose media, line51corresponds to a short grain direction of multipurpose media, line52corresponds to a long grain direction of recycled media, line53corresponds to a short grain direction of recycled media, line54corresponds to a short grain direction of photopaper media and line55corresponds to a long grain direction of photopaper media. Other types of media may be used and analyzed using media sensing system26in other embodiments. InFIG. 4, the intensity values drop with respect to time due to temperature changes during operation of the light sources configured as LEDs in one embodiment.

Referring toFIG. 5, another graphical representation of intensity information of signals outputted from media sensing system26is shown as an orthogonal difference measurement for different types of media16. InFIG. 5, line60corresponds to a difference measurement for multipurpose media, line61corresponds to a difference measurement for recycled media, line62corresponds to a difference measurement for photopaper media, line63corresponds to a difference measurement for photopaper media and line64corresponds to a difference measurement for HP Presentation media. As shown, the results of difference measurement (FIG. 5) are substantially flat showing that difference measurements negate transient output due to LED light output instability as temperature of the light sources changes over time (FIG. 4).

As illustrated inFIG. 5, there is a direct correlation between physical media grain and sensor output by taking the difference between illuminated orthogonal directions. Media with high anisotropy (e.g., recycled media) has an increased optical difference compared with lower anisotropy media (e.g., HP Presentation media) with minimal grain. The difference results are larger for types of media having increased grain compared with types of media having minimal grain.

Processing circuitry20is configured to control operations of device10using information from media sensing system26regarding grain of the media16being imaged upon. For example, cut sheet media of unknown grain direction may be a source of cockle issues (e.g., localized deformation in the paper which may extend out of the plane of the paper) in relatively high throughput inkjet configurations of device10. Operations of device10may be configured corresponding to the direction of the grain of the media16to reduce or minimize hard imaged media cockle. In addition, some sheet operations, such as folding, perfect binding or trimming, are highly dependent on media grain to attain improved quality results.

Imaging in conventional imaging applications, which operate independent of knowledge of orientation of grain, may be negatively impacted by having to account for grain directions of unknown orientation. For example, with inkjet printing devices, it may be desirable to subject media having grain oriented in the scan direction to additional drying cycles (compared with media having grain oriented in the process direction) to evaporate an additional amount of water from the media to reduce cockling. Accordingly, printing speeds of inkjet printers may be slowed to account for media having grain of unknown orientation to enable additional drying cycles to evaporate water to yield stable media. Accordingly, the throughput of such a device would be reduced to implement the additional drying cycles for media having grain oriented in both process and scan directions although such are typically not needed for media having grain oriented in the process direction as mentioned above.

According to an embodiment of the disclosure, hard imaging device10may utilize the information regarding the direction of the grain of the media16to control operations of device10. Additional operations may be performed and/or operations may be modified upon detection of media16having grain oriented in the scan direction compared with media16having grain oriented in the process direction to reduce cockling or curling. In one example described above, heating of media can be controlled (e.g., additional drying cycles may be performed by image engine28) to evaporate an increased amount of water in inkjet printing of media16having grain oriented in the scan direction. In another example, the processing circuitry20may control operations regarding the provision of the marking agent upon the media (e.g., the processing circuitry20may control the formation of ink droplets having different amounts of ink and/or water corresponding to the orientation of the grain of the media16to reduce cockling). In a laser based imaging example, a processing speed of a fuser of image engine28may be adjusted responsive to the detection of the orientation of the grain of media. In another example, de-curling operations, such as passing media16having grain oriented in the scan direction through de-curling rollers (or perhaps providing for additional passages through the rollers), may be performed to reduce cockling.

In another example, it may be desirable for operators to know the orientation of the grain so appropriate action may be taken prior to imaging (e.g., prior to imaging in a desktop publishing application). More specifically, it may be desirable to orient media in a given direction prior to imaging to yield improved results. In some specific examples, it may be desired to orient the media such that the grain is in the direction in which the media will be cut, folded or bound. According to one implementation, the processing circuitry20of the hard imaging device10may detect the orientation of the grain of the media and may control an operation of the device10if the orientation is not in the appropriate direction for the imaging to be performed. In one example, the processing circuitry20may access information regarding the imaging to be performed (e.g., cutting, folding, binding, etc.) and control the generation of a human perceptible message by display24to request the operator to re-align the direction of the grain of the media16in the appropriate direction for the imaging and finishing to be performed if such is not properly aligned.

The above are examples of illustrative operations of the hard imaging device10which may be performed and/or modified using information provided by the media sensing system26regarding the detected direction of the grain of the media16. Other operations of device10may be performed and/or modified in other configurations, implementations or applications of the hard imaging device10in other embodiments.

Referring toFIG. 6, an example of a method which may be performed by hard imaging device10using information regarding the direction of grain of the media is shown. Processing circuitry20of the hard imaging device10may implement the depicted method in one embodiment. Other methods which include more, less and/or additional acts are possible in other embodiments.

At an Act A10, the processing circuitry may access the signals outputted by the media sensing system and may process the signals to determine the direction of the grain of the media to be imaged upon. As mentioned above, a short grain direction of media typically reflects additional light compared with a long grain direction of the media and accordingly the signal having the greater intensity may be used to indicate the direction of the grain in one embodiment.

At an Act A12, the processing circuitry may control an operation of the hard imaging device with respect to hard imaging if appropriate. In one example, the processing circuitry may adjust an operation of the image engine using the grain direction information. In another example, the processing circuitry may control the communication of appropriate messages to an operator based upon the imaging to be performed. Hard imaging upon the media may be performed by the control of the processing circuitry in accordance with the detected direction of the grain of the media. Other operations may be controlled by the processing circuitry using the grain direction information in other embodiments.

Further, aspects herein have been presented for guidance in construction and/or operation of illustrative embodiments of the disclosure. Applicant(s) hereof consider these described illustrative embodiments to also include, disclose and describe further inventive aspects in addition to those explicitly disclosed. For example, the additional inventive aspects may include less, more and/or alternative features than those described in the illustrative embodiments. In more specific examples, Applicants consider the disclosure to include, disclose and describe methods which include less, more and/or alternative steps than those methods explicitly disclosed as well as apparatus which includes less, more and/or alternative structure than the explicitly disclosed structure

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.