Patent Application
20140306399
Printers use a variety of media types, for example plain paper, photo paper, transparencies, card stock and the like. The different media types vary in the surface finish of the media, thickness or weight of the media, stiffness of the media, material of the media and the like.
There are many types of printers, for example LaserJet printers and inkjet printers. Most home or office printers, regardless of the type, feed sheets of media from an input tray through a paper path, past a print zone, and into an output tray. At the beginning of the paper path, a pick system is used to separate the top sheet from the stack of sheets located in the input tray. Once the top sheet has been separated, it is fed through the paper path, past the print zone, and into the output tray.
The pick system typically comprises a pick roller, a separation pad or separation roller, some type of spring tensioning system and may contain a motor lift mechanism. The pick system is typically optimized for the media type most commonly used in the home or office environment. The most commonly used media in the home and office is plain paper. Therefore the pick system is typically optimized for plain paper. When optimizing a pick system, the weight or thickness of the media, the surface finish of the media, the stiffness of the media and the material of the media are considered.
When other types of media that have different characteristics are loaded into the input tray, the pick system may not perform as well. For example, when very thin or light weight media is used, the pick system may have more frequent multi-pick events. A multi-pick event is when more than one sheet of media is fed into the paper path at the same time. When thick media or media with a slick surface finish is loaded into the input tray, the frequency of mispick events may increase. A mispick event is when the pick system is unable to pick the top sheet of media from the stack of media. In some cases a skewed-pick event may occur. A skew-pick event is where the page is picked and separated from the rest of the stack, but some problem causes the page to not be parallel with the paper path direction.
Modern printers are typically designed to print a large number of pages over the life of the printer. Some parts of the printer may wear out quicker than other parts. For example the pick roller in a pick system may wear out before the rest of the print engine. When the pick roller begins to wear out, the frequency of mispicks or multi-picks may increase. Many printers have pick rollers that are user replaceable. Pick rollers are fairly inexpensive compared to the print engine. Therefore replacing the inexpensive pick roller extends the useful life of the more expensive print engine. Currently the pick roller replacement part is the same design as the original pick roller. Therefore when the pick roller is replaced, the pick system is still optimized for plain paper.
In one example, a number of different pick rollers will be available where each pick roller set is designed or tuned for a different type of media. Because the pick roller is user replaceable, a user can select a pick roller set to match the type of media they wish to use. Once the pick roller tuned for that media type is installed, the pick system will have fewer mispicks or multi-picks for media that is different from plain paper. When the user is done using the specialty media and is ready to go back to plain paper, the original pick roller (or a pick roller tuned for plain paper) can be re-installed back into the printer.
By providing a number of different pick roller sets, with each pick roller set tuned for a different media type or groups of media types, good performance of the pick system can be broadened across a much wider range of media types (e.g. the gamut of media types the printer will successfully pick is broadened). In some examples, other pieces of the pick system may also be tuned for different media types, for example the separation roller or separation pad, as well as the spring tensioning device. A number of sets of pick parts may be provided with each set of parts tuned for a different type of media.
Pick roller 108 has a tensioning system (114 and 106) that controls the force between the pick roller and the top sheet of media 118 in the input tray. The tensioning system may comprise springs, pivot arms, mounting brackets and the like. The amount of force used in tensioning system (114 and 106) may depend on the type of media the pick system is tuned for. Separation roller 110 prevents multiple sheets of media from being passed through the paper path at the same time.
In this example the pick roller 108, the separation roller 110 and at least one spring in the tensioning system (114 and 106) are user replaceable. When the printer is shipped, the pick roller 108, the separation roller 110 and the tensioning system (114 and 106) installed in the printer are tuned for the most commonly used papers (for example plain paper) or media types. When the user wishes to use media that differs from the most commonly used plain paper or plain media types, one or more of the user replaceable parts can be swapped out for parts tuned for that media. In some examples. the pick roller 108, the separation roller 110 and a spring in the tensioning system (114 and 106) may need to be swapped out to tune the pick system for a particular type of media. In other examples only the pick roller may need to be swapped out for a different type of media.
In one example the replacement parts come in different sets of replacement parts, with each set of replacement parts tuned for a different type of media or group of media types. In some examples one or more of the parts in a set of replaceable parts may be color coded. The color code can be matched up with the type of media that set of replacement parts are tuned for. For example, a green color may indicate a set of parts tuned for thin media. A blue color may indicate that the set of replacement parts is tuned for thick or stiff media. In one example the set of parts tuned for plain paper are not marked with a color. In other examples, the set of parts tuned for plain paper will be marked with a color. There may be a number of different sets of replaceable parts. In some examples there may be between 2 and 15 different sets of replacement parts, for example 5 sets of replacement parts. The side of a part or the surface of the part may be the area marked with the different colors or perhaps the whole part structure may be molded in a particular color.
Some types of media may require three or more user replaceable parts to be included in the set of replacement parts for that type of media. Other types of media may only require one or two of the user replaceable parts to tune the pick system for that type of media.
When tuning the pick system for different media types, the parameters of the different replaceable parts may be varied.
Compression material 226 is typically a flexible material, for example rubber or foam. Compression material in conjunction with the tensioning system, controls how much the surface of outer material deforms when making contact with the media. When compression material 226 is softer or more flexible, more of the surface area of outer material contacts the top sheet of media. Softer or more flexible material can be used to tune the pick roller for stiffer or heavy weight media. When compression material 226 is stiffer or less flexible, less of the surface area of outer material contacts the top sheet of media. Stiffer or less flexible material can be used to tune the pick roller for thin or light weight media. The change in stiffness can be accomplished by a change in material, a change in the physical layout of the part, or both.
Outer material 224 may be selected for its surface properties. Some of the surface properties that can be varied include the roughness of the surface or surface finish, the tackiness or stickiness or the surface, the hardness of the surface, the compliance of the material and the like. These properties generally control the coefficient of friction of the surface of the pick roller. The surface finish can be varied from a smooth finish, to a rough finish, or even a surface with treads or sipings (like a tire). The change in the coefficient of friction of the surface of the pick roller can be accomplished by a change in material, a change in the surface finish, or both. A smooth finish can be used for thin or light weight media. A rough surface or compliant material can be used for a stiff or heavy weight media. In some examples the pick roller may be fabricated from a single material and no outer material 224 is used.
Other properties of the pick roller may be varied, for example the width of the pick roller. A full width pick roller may be used for standard sized paper. A narrower pick roller may be used for media that is not as wide as letter sized paper, for example an envelope.
Similar variations in properties can be used to tune the separation roller or the separation pad for different media types. The tensioning system (114 and 106) can be tuned for different media types by changing one or more springs in the tensioning system (114 and 106). A stronger spring force may be used for stiff or heavy weight media and a weaker spring force may be used for thin or light weight media. The material and design of the roller surface may also be varied to withstand certain paper additives such as calcium carbonate and the like.
In some examples, a label or mark may be attached to the media packaging material. The label or mark may indicate which set of replaceable parts work best for that type of media. In one example the label may match the color code of one of the sets of replaceable parts. In another example the label may indicate the set of replaceable parts to use for the media, for example use the thin media replacement parts. In yet another example, both types of information may be included on the label. In this way the user can easily select the correct set of replaceable parts for the media they wish to use.
In some examples the printer may determine that a different type of media is being used. Some printers have sensors that can measure different media properties, for example surface finish, stiffness, color, thickness, and the like. When the sensors detect a different type of media being used, the printer may recommend a different set of pick parts. In this case the printer may recommend, based on the measured media properties, the set of replaceable pick parts to use with the type of media loaded in the printer.
In other examples, the printer may determine that a different type of media is in use or that a different set of replaceable pick parts is needed by tracking errors in the pick system. The printer may track errors related to the print path and recommend a set of replaceable parts based on recorded errors or machine analysis of combinations, patterns, or frequency of errors. For example when the printer detects a higher frequency of mispicks, the printer may recommend a set of replacement parts tuned for stiffer or heavy weight media. When the printer detects a higher frequency of multi-picks, the printer may recommend a set of replacement parts tuned for thinner or light weight media. The recommendation may be triggered when the frequency of errors exceeds a threshold.
I/O module 306 is used to couple printer to other devices, for example the Internet or a computer. Printer has code, typically called firmware, stored in the memory 304. The firmware is stored as computer readable instructions in the non-transitory computer readable medium (i.e. the memory 304). Processor 302 generally retrieves and executes the instructions stored in the non-transitory computer-readable medium to operate the printer and to execute functions. In one example, processor executes code that recommends a replacement part set.
