Patent Application
20150030356
Systems and methods herein generally relate to printing devices and more particularly to charge blades within electrostatic printing devices.
Electrostatic printing devices deliver a controlled amount of charged marking material (e.g., toner) to a photoreceptor (or other element capable of maintaining a latent image charge) using what is sometimes referred to as a development roll. The marking material is transferred from the development roll to the photoreceptor, and then from the photoreceptor to a sheet of media to perform printing on the sheet.
The marking material is usually in the form of a powder, such as toner particles. In order to control (or “meter”) the amount of marking material that exists on the development roll, a blade is used to scrape excess amounts of marking material off the development roll. In addition, the blade can provide a charge to the marking material particles and, therefore, the blade is sometimes referred to as a “charge blade.”
An exemplary printing apparatus herein includes a sheet feeder and a photoreceptor adjacent the sheet feeder. The photoreceptor receives print media from the sheet feeder, and the photoreceptor transfers toner to the print media. A development roll is adjacent the photoreceptor. The development roll supplies a metered amount of charged toner to the photoreceptor. Also, a supply roll is adjacent the development roll. The supply roll supplies toner to the development roll. In this device, a charge blade contacts the development roll, and a charge generator is electrically connected to the charge blade, supply roll, and development roll.
The charge blade has a middle portion and an end portion. The end portion of the charge blade touches the development roll. The charge blade applies a force against the development roll to enable friction between the toner and the development roll, which electrically charges the toner. The end portion of the charge blade comprises a first curved surface and a second curved surface touching the development roll. The second curved surface is positioned, on the charge blade, between the first curved surface and the middle portion of the charge blade. Thus, the first curved surface is a longer distance from the middle portion of the charge blade relative to the second curved surface. The first curved surface also has a smaller radius relative to a larger radius of the second curved surface.
The development roll has an outer surface moving in a first direction. The first curved surface of the end portion of the charge blade is positioned before the second curved surface in the first direction. Therefore, the moving outer surface of the development roll contacts the first curved surface before contacting the second curved surface (when moving in the first direction). Also, the first curved surface of the end portion of the charge blade comprises a first contact area touching the surface of the development roll and, similarly, the second curved surface of the end portion of the charge blade comprises a second contact area touching the surface of the development roll. The first contact area and the second contact area are parallel linear areas running in a second direction perpendicular to the first direction (from side to side, across the surface of the development roll).
Additionally, the outer surface of the development roll is a curved surface. There may be additional “second” curved surfaces between the second curved surface and the middle portion of the charge blade. The contact areas of all such curved surfaces are positioned in an arc, such that all of the contact areas of the curved surfaces simultaneously touch the curved outer surface of the development roll.
The first curved surface produces a first amount of charge in the toner on the development roll, and the second curved surface increases the charge within the toner on the development roll (e.g., to a second amount of charge that is larger than the first amount of charge). Also, the smaller radius of the first curved surface controls the amount of toner positioned on the development roll and the larger radius of the second curved surface does not affect the amount of toner metered by the first, smaller radius curved surface.
Stated in more generic terms, various print devices herein include a media feeder (one example of which is a sheet feeder); and a transfer device (one example of which is a photoreceptor) adjacent the media feeder. The transfer device receives print media from the media feeder, and the transfer device transfers marking material (one example of which is a toner) to the print media. A marking material feeder (one example of which is a development roll) is adjacent the transfer device. The marking material feeder supplies the marking material to the transfer device. Further, a supply device (one example of which is a supply roll) is adjacent the marking material feeder. The supply device supplies the marking material to the marking material feeder.
A charge blade contacts the marking material feeder, and a charge generator is electrically connected to the charge blade, supply roll, and development roll. The charge blade has a middle portion and an end portion. The end portion of the charge blade touches the marking material feeder, and the end portion of the charge blade applies a force against the development roll to enable friction between the toner and the development roll, which electrically charges the toner.
Again, the end portion of the charge blade comprises a first curved surface (e.g., a consistent/uniform arc shape) touching the marking material feeder and a second curved surface (e.g., also a consistent/uniform arc shape, but different from the first curved surface) touching the marking material feeder. The second curved surface is positioned, on the charge blade, between the first curved surface and the middle portion of the charge blade. Thus, the first curved surface is located/positioned a longer distance from (is further away from) the middle portion of the charge blade relative to the second curved surface. While both have arc shapes, the first curved surface has a smaller radius relative to a larger radius of the second curved surface.
The marking material feeder has an outer surface moving (e.g., rotating) in a first direction. The first curved surface is positioned before the second curved surface in the first direction (the second curved surface is positioned between the first curved surface and the middle portion of the charge blade) such that the rotating outer surface of the marking material feeder contacts the first curved surface before contacting the second curved surface (when moving in the first direction). Also, the first curved surface has a first contact area touching the curved outer surface of the material feeder, and the second curved surface similarly has a second contact area touching the curved outer surface of the material feeder. The first contact area and the second contact area form parallel linear areas running in a second direction perpendicular to the first direction (running from one edge of the outer surface of the marking material feeder to the opposite edge across the outer surface of the marking material feeder).
Additional curved surfaces can be positioned between the second curved surface and the middle portion of the charge blade. The first curved surface and the additional curved surfaces comprise contact areas touching the curved outer surface of the marking material feeder. The contact areas of the first curved surface and the additional curved surfaces are positioned in an arc, and all of the contact areas simultaneously touch the curved outer surface of the marking material feeder.
The first curved surface produces a first amount of charge in the marking material on the marking material feeder, and the second curved surface increases the charge within the marking material on the marking material feeder (to a second amount of charge that is larger than the first amount of charge). Also, the smaller radius of the first curved surface controls (meters) the amount of marking material positioned on the marking material feeder, and the larger radius of the second curved surface does not affect the amount of marking material metered on the marking material feeder by the first curved surface.
These and other features are described in, or are apparent from, the following detailed description.
Various exemplary systems and methods are described in detail below, with reference to the attached drawing figures, in which:
As mentioned above, a charge blade is used to remove excess amounts of marking material from the development roll and provide a charge to the marking material particles, thereby “metering charged particles” on the development roll. The devices described herein include multiple rounded (curved) contact points having different radii at the end portion of the charge blade to provide precise metering and charge control of marking material particles on a development roll.
The physical structures described herein allow many different types of marking materials to be used in printing devices that require highly controlled charge and metering levels (and would otherwise require specialized marking materials). Therefore, in one example, the physical structures described herein allow a wider variety of marking materials to be used in devices that require a specific type of marking material, allowing less-polluting, lower-cost marking materials to be used in place of more expensive, more rare marking materials. This promotes more recycling of printing cartridges by a wider range of manufacturers, increasing competition, reducing consumer prices, and helping the environment.
As shown in
A charge generator 120 can transfer charge to a charge blade 114 and the charge blade 114 can apply a force against the development roll 112 to generate friction between the toner T and the development roll 112, which electrically charges the toner. The charge blade scrapes off excess toner T from the development roll 112 to meter (control) the amount of toner T that remains on the development roll 112 as the surface of the development roll 112 moves toward a photoreceptor 18. Thus, as the development roll 112 rotates as shown by arrow C, the toner T is charged and metered in the nip H of the charge blade 114 that is held in contact against the development roll 112 with a pre-determined force. After the surface of the development roll 112 moves past the charge blade 114, enough charged toner T is brought into the development zone G (at the nip G where the development roll contacts the photoreceptor 18) to support acceptable solid area and halftone uniformity on the latent image on the photoreceptor 18.
The charge blade 114 can be made of any electrically conductive material, such as a thin piece of metal (e.g., steel, bronze, copper, etc.), plastic, polymer, alloy, etc., that is mounted on a rigid holder connected to the development housing. The physical properties and the dimensions of the charge blade 114 (i.e. modulus, thickness, free length, etc.) are selected to provide an optimal normal force against the development roll 112 that will provide good charging and metering of the toner that enters into the nip H. As shown by the force arrow in the drawings, the blade force is perpendicular to the developer roll 112 circumference.
When some non-standard toners (e.g., toners other than those called for by the printer manufacturer) are used, they may not be able to charge fast enough with conventional flat charge blades that have a relatively smaller nip than the nip H shown in the accompanying drawings. This can lead to low density and higher background than the original toner call for by the manufacturer.
The structures presented herein provide improved metering and charging of a toner layer within a development cartridge. By providing multiple contact points (nips) between the charge blade and the development roll, the toner layer has more frictional area to charge, which creates a charge that is sufficiently high, and sufficiently uniform, to enable good development to the photoreceptor with no background. By providing more frictional charging area, these devices can handle a toner design that may not charge as well as the toner originally designed for a given printer. The radius of the first curved surface 134 provides both a nip forming feature, and a metering function. As the radius is reduced, the amount of toner provided to the development zone is reduced. Subsequent radii in the second and third curves surfaces 132, 130 are larger than the radius of the first curved surface 134 to ensure no toner is metered by the second and third curves surfaces 132, 130, but the second and third curves surfaces 132, 130 provide frictional charging to increase the amount and uniformity of the charge within the toner.
Stated in more generic terms, various print devices 10 (see
A charge blade 114 contacts the marking material feeder 112, and a charge generator 120 is electrically connected to the charge blade 114. The charge blade 114 has a middle portion 122 and an end portion 124. The middle portion 122 and the end portion 124 of the charge blade 114 can be formed of a single piece of continuous material, or can be formed separately and later attached to one another. The end portion 124 of the charge blade 114 includes curved structures 130-134 that touch the marking material feeder 112, and the end portion 124 of the charge blade 114 applies a force against the development roll 112 to enable friction between the toner T and the development roll 112, which electrically charges the toner.
Again, the end portion 124 of the charge blade 114 comprises a first curved surface 134 (e.g., a consistent/uniform arc shape) touching the marking material feeder 112, a second curved surface 132 and additional curved surfaces 130 (e.g., also a consistent/uniform arc shape, but having a radius different from the first curved surface 134) touching the marking material feeder 112. The second curved surface 132 is positioned, on the charge blade 114, between the first curved surface 134 and the middle portion 122 of the charge blade 114. Thus, the first curved surface 134 is located/positioned a longer distance from (is further away from) the middle portion 122 of the charge blade 114 relative to the second curved surface 132. Similarly, the additional curved surfaces 130 (one of which is illustrated) are positioned, on the charge blade 114, between the second curved surface 132 and the middle portion 122 of the charge blade 114. While all have uniform arc shapes in cross-section, the first curved surface 134 has a smaller radius relative to the larger radius of the second curved surface 132. Further, the additional curved surfaces 130 can have the same radius as the second curved surface 132 or can have even larger radii (however, the first curved surface 134 has the smallest radius).
The marking material feeder 112 has an outer surface moving (e.g., rotating) in a first direction. The first curved surface 134 is positioned before the second curved surface 132 in the first direction (the second curved surface 132 is positioned between the first curved surface 134 and the middle portion 122 of the charge blade 114) such that the rotating outer surface of the marking material feeder 112 contacts the first curved surface 134 before contacting the second curved surface 132 (when moving in the first direction). Also, the first curved surface 134 has a first contact area touching the curved outer surface of the material feeder, and the second curved surface 132 similarly has a second contact area touching the curved outer surface of the material feeder. As shown most clearly in
The first curved surface 134 and the additional curved surfaces 130 comprise contact areas touching the curved outer surface of the marking material feeder 112, thereby forming at least two nips (at least two different linear areas of contact between the charge blade 114 and the marking material feeder 112). As shown most clearly in
The first curved surface 134 removes marking material T and produces a first amount of charge in the marking material T on the marking material feeder 112. The second and additional curved surfaces 132, 130 do not remove any additional marking material (because they have larger radii than the first curved surface 134) but the second and additional curved surfaces 132, 130 increase the amount of, and uniformity of, charge within the marking material T on the marking material feeder 112 (to a second amount of charge that is larger and more uniform than the first amount of charge). Thus, the smaller radius of the first curved surface 134 performs all the metering of marking material T positioned on the marking material feeder 112, and the larger radius of the second curved surface 132 does not affect the amount of marking material T metered on the marking material feeder 112 by the first curved surface 134, but simply make the charge more uniform and increase the charge.
Referring to the
An electronic or optical image or an image of an original document or set of documents to be reproduced may be projected or scanned onto a charged surface 13 or a photoreceptor belt 18 to form an electrostatic latent image. The belt photoreceptor 18 here is mounted on a set of rollers 26. At least one of the rollers is driven to move the photoreceptor in the direction indicated by arrow 21 past the various other known electrostatic processing stations including a charging station 28, imaging station 24 (for a raster scan laser system 25), developing stations 80-83, and transfer station 32. Note that devices herein can include a single development station 80, or can include multiple development stations 80-83, all of which include the charge blade 114 discussed above.
Thus, the latent image is developed with developing material to form a toner image corresponding to the latent image. More specifically, a sheet 15 is fed from a selected paper tray supply 33 to a sheet transport 34 for travel to the transfer station 32. There, the toned image is electrostatically transferred to a final print media material 15, to which it may be permanently fixed by a fusing device 16. The sheet is stripped from the photoreceptor 18 and conveyed to a fusing station 36 having fusing device 16 where the toner image is fused to the sheet. A guide can be applied to the substrate 15 to lead it away from the fuser roll. After separating from the fuser roll, the substrate 15 is then transported by a sheet output transport 37 to output trays a multi-function finishing station 50.
Printed sheets 15 from the printer 10 can be accepted at an entry port 38 and directed to multiple paths and output trays 54, 55 for printed sheets, corresponding to different desired actions, such as stapling, hole-punching and C or Z-folding. The finisher 50 can also optionally include, for example, a modular booklet maker 40 although those ordinarily skilled in the art would understand that the finisher 50 could comprise any functional unit, and that the modular booklet maker 40 is merely shown as one example. The finished booklets are collected in a stacker 70. It is to be understood that various rollers and other devices, which contact and handle sheets within finisher module 50, are driven by various motors, solenoids and other electromechanical devices (not shown), under a control system, such as including the microprocessor 60 of the control panel 17 or elsewhere, in a manner generally familiar in the art.
Thus, the multi-functional finisher 50 has a top tray 54 and a main tray 55 and a folding and booklet making section 40 that adds stapled and unstapled booklet making, and single sheet C-fold and Z-fold capabilities. The top tray 54 is used as a purge destination, as well as, a destination for the simplest of jobs that require no finishing and no collated stacking. The main tray 55 can have, for example, a pair of pass-through sheet upside down staplers 56 and is used for most jobs that require stacking or stapling
As would be understood by those ordinarily skilled in the art, the printing device 10 shown in
Many computerized devices are discussed above. Computerized devices that include chip-based central processing units (CPU's), input/output devices (including graphic user interfaces (GUI), memories, comparators, processors, etc. are well-known and readily available devices produced by manufacturers such as Dell Computers, Round Rock Tex., USA and Apple Computer Co., Cupertino Calif., USA. Such computerized devices commonly include input/output devices, power supplies, processors, electronic storage memories, wiring, etc., the details of which are omitted herefrom to allow the reader to focus on the salient aspects of the systems and methods described herein. Similarly, scanners and other similar peripheral equipment are available from Xerox Corporation, Norwalk, Conn., USA and the details of such devices are not discussed herein for purposes of brevity and reader focus.
The terms printer or printing device as used herein encompasses any apparatus, such as a digital copier, bookmaking machine, facsimile machine, multi-function machine, etc., which performs a print outputting function for any purpose. The details of printers, printing engines, etc., are well known and are not described in detail herein to keep this disclosure focused on the salient features presented. The systems and methods herein can encompass systems and methods that print in color, monochrome, or handle color or monochrome image data. All foregoing systems and methods are specifically applicable to electrostatographic and/or xerographic machines and/or processes.
In addition, terms such as “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “upper”, “lower”, “under”, “below”, “underlying”, “over”, “overlying”, “parallel”, “perpendicular”, etc., used herein are understood to be relative locations as they are oriented and illustrated in the drawings (unless otherwise indicated). Terms such as “touching”, “on”, “in direct contact”, “abutting”, “directly adjacent to”, etc., mean that at least one element physically contacts another element (without other elements separating the described elements). Further, the terms automated or automatically mean that once a process is started (by a machine or a user), one or more machines perform the process without further input from any user.
It will be appreciated that the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intend portioned to be encompassed by the following claims. Unless specifically defined in a specific claim itself, steps or components of the systems and methods herein cannot be implied or imported from any above example as limitations to any particular order, number, position, size, shape, angle, color, or material.
