This disclosure relates generally to systems for cleaning image surfaces in printers, and more particularly, to systems for cleaning image surfaces in printers that treat image receiving surfaces with surface preparation materials.
Some inkjet printing systems or printers that treat image receiving surfaces with surface preparation materials include a cleaning device to remove certain materials from an image surface without removing all of the surface preparation material for the next printing cycle. Surface preparation material is any substance applied to support the image receiving surface to enable an ink image to be formed and to facilitate in the transfer of the ink image to media. Examples of a surface preparation material or a blanket coating include, but are not limited to, a skin coating, a fluid coating, a combination thereof, or the like. In some previously known systems, a blade cleaner is used to remove materials from the image surface. The materials removed from an image surface to replenish the ability of the image surface to form quality images include ink, surface preparation substances, media debris, and the like. Blade cleaners are effective because they can provide higher pressures on the imaging surface, but these pressures can result in a shorter life of the image forming surface and the blade cleaner. These drawbacks of using a blade cleaner increase the operating costs of operating the printer system.
To address the issues related to blade cleaners, some previously known aqueous ink printing systems have used a foam roller that rotates against the movement of the surface to be cleaned to scruff and carry material away from the surface. In aqueous ink printing systems, the image receiving surface that is cleaned by the foam roller is a blanket of material wrapped around an endless support surface, such as a rotating drum or belt. To enhance the surface properties of the blanket so ink adheres to it during image formation and then releases the ink image during transfer to media, the blanket is treated with a surface preparation material that forms a skin on the blanket surface. This surface preparation material is applied to the surface of the blanket after the ink image has been transferred to media and the blanket surface has been cleaned of the skin and residual ink from the previous imaging cycle. Ideally, the pressure of the foam roller should split and remove the ink layer while only hydrating the skin layer so it can be replenished. If the pressure applied to the blanket by the foam roller is too high, however, the thin skin layer under the ink layer also splits. This splitting of the skin layer enables some of the loosened ink to contact the blanket surface, which has an affinity for the ink. Consequently, the ink adheres to the blanket surface and is harder to remove than ink on the skin preparation material. Thus, the cleaning of the blanket is adversely impacted and image quality can be affected in subsequent imaging cycles.
In certain previously known aqueous ink printing systems, the ink is dried to a semi-wet consistency to enable the transfer of the ink image onto media before the imaging surface is cleaned by the cleaning device. In most cases, the semi-wet ink is easier to clean since the density of the ink is small. However in certain cases, the ink is over-dried. Over-dried ink can occur regularly in machine operation due to machine faults. For example, faults such as media handling faults, control faults and other situations can result in the machine shutting down during the printing operation. The processing of these faults can leave the ink image under the dryers longer than desired. The extra drying can over dry the ink and make the dried ink harder to clean. Over drying can also reduce efficiency of the ink image transfer to the media causing a larger amount of the harder-to-clean ink to be introduced to the cleaning device in the printer system. To compensate for the occurrence of these situations, a blade cleaner may be employed rather than a foam roller cleaner since the blade cleaner can apply the higher pressures required to remove dried ink with the attendant risks noted previously.
A printer cleaning device has been configured to enable the removal of material from a cleaning surface of a printer. The printer cleaning device is included in a printing system that treats an image receiving surface with a surface preparation material. The printer cleaning device includes an applicator configured to receive fluid from a source of fluid, an actuator operatively connected to the applicator, a wiper configured to engage the image receiving surface after the image receiving surface has passed by the applicator, and a controller operatively connected to the actuator. The controller is configured to operate the actuator to apply fluid to the image receiving surface selectively to enable the wiper to remove the fluid and material from the image receiving surface.
A new method of cleaning that enables removal of material from a an image receiving surface with a surface preparation material. The method includes operating an actuator with a controller to move an applicator into contract with the image receiving surface to apply fluid to the image receiving surface selective. The method further includes wiping the image receiving surface with a wiper after the image receiving surface has passed the applicator to enable the wiper to engage the image receiving surface and remove material from the image receiving surface.
The foregoing aspects and other features of a printer cleaning device that enables the removal of a material are explained in the following description, taken in connection with the accompanying drawings.
For a general understanding of the present embodiments, reference is made to the drawings. In the drawings, like reference numerals have been used throughout to designate like elements.
Materials can be any substance that is carried by the surface of the blanket 112 after the blanket 112 passes through the nip that transfers an image to media. Examples of materials on the surface 112 include, but are not limited to, aqueous ink, semi-dried aqueous ink, surface preparation material layers or skin layers, debris, combinations thereof, or the like Ink can be any substance applied to the image receiving surface to produce an image that is transferred to media. Fluid 116 can be any substance that hydrates a material such as ink or a surface preparation material. Examples of the fluid 116 include, but are not limited to, water, a solvent, a dilate solution of a solvent with water, or the like. Examples of the applicator 104 include, but are not limited to, a foam pad, a foam roller, a sprayer, or the like to enable the fluid to be wiped or sprayed onto the surface of the blanket 112. In the illustrated embodiment, an actuator 110 is operatively connected to the applicator 104 and a controller 114 is operatively connected to the actuator 110 to operate the actuator 110 and rotate the applicator 104 in a direction opposite to the motion of the surface of the blanket 112. Alternatively, the applicator 104 can be a free rolling roller that rotates in the direction of movement of the blanket 112. In another example, the applicator 104 can be an open cell foam roller positioned inside the receptacle 140 so that it is saturated with water inside the receptacle and the applicator 104 rotates to apply the water to the surface of the blanket 112.
A wiper 108 contacts the surface of the blanket 112 with sufficient force to dislodge the hydrated materials from the surface of the blanket 112 so they can be carried away from the blanket by the fluid on the blanket that builds against the wiper. The wiper 108 is fixed at a predetermined angle with the blanket 112. In one example, the predetermined angle is 75 degrees, although other angles can be useful depending upon the properties of the materials being removed from the surface of the blanket. The wiper 108 can also dry the surface of the blanket to some degree. Examples of the wiper 108 include, but are not limited to, an elastomeric blade, a Polyurethane blade such as Synztec 238707 70 Shore A durometer, a xerographic blade, a higher durometer polyurethane blade, a urethane blade, other elastomers, or the like.
In the operation of the cleaner 100 shown in
A pump 120 forces the removed combination 136 through the conduit 144 and the filter 124 to separate the ink and surface preparation material from the fluid 116. The filtered fluid 148 is returned to the receptacle 140. In one example, a portion of the fluid 116 is lost during the filtration process, for example, due to evaporation. As such, additional fluid 116 from another source (not shown) can be provided to the source 140. The separated materials from the filter 124 can be collected for disposal within, for example, the filter 124, a filter media inside the filter 124, a separate container 128, or the like.
The filter 124 can provide micro-filtration, ultra-filtration, nano-filtration, reverse osmosis, combinations thereof, or the like to separate the materials from the combination 136. The filter 124 can include a porous filter media having very small pore sizes to separate the materials from the combination 136. In one example, different filter medias of varying pore sizes can be used to filter different materials from the combination 136. For example, the filter 124 includes very small pore sizes such as a pore size of about less than 0.01 μm. The filter 124 also includes a skin filter having a pore size of about less than 10 μm. A larger pore size may be required to filter the skin because the components of the skin are larger and can clog the pores required to filter ink. In another example, a series of progressively smaller pore size filters are positioned inside the filter 124 to efficiently separate different materials from the combination 136. The reader should understand that these parameters are exemplary and other pore sizes or filter materials can be used to separate the materials from the combination 136. In one example, the pump 120 can be operated in reverse to pull filtered fluid from the receptacle 140 and through the filter 124 to back-flush the filter and remove filtered materials from the filter media to enable reuse of the filter media. Alternatively, the filter can be back-flushed with other techniques that include, but are not limited to, using a machine, an external reclamation process, or removing and washing the filter media.
It will be appreciated that variations of the above-disclosed apparatus 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 intended to be encompassed by the following claims.