Patent Grant
9372466
This disclosure is generally directed to a cleaning blade of an electrophotographic printing device. More specifically, this disclosure is directed to a cleaning blade lubricant having a high aspect ratio that improves toner cleaning performance against a photoreceptor of an electrophotographic printing device.
Copiers and printers containing photoconductors create a latent image which is developed by using toner. The toner on the photoconductor then transfers to paper or appropriate intermediate which then travels through a heater which fixes the toner particles on the paper. The transfer of toner particles from the photoconductor to the paper or intermediate is not 100% complete. There are residual toner particles on the photoconductor that need to be removed. It is common to remove the remaining toner particles on the photoconductor after each transfer process by using a cleaning device, such as a cleaning blade.
Non-magnetic single component development (SCD) toner requires high flowability and high chargeability because the time for toner to flow through the contacting nip formed between the charge blade and the development roll is very short. Low charge causes reduced solid area development, increased toner dusting in white areas of the page (background), poor development stability over time, ghosting, and/or white bands.
For good cleaning performance of any un-transferred toner, the forces acting near the cleaning blade are such that there is sufficient force against the photoreceptor to prevent toner from getting underneath, but not so much force to damage the cleaning blade edge during operation and continued print cycles. Cleaning performance degrades when the edge of the blade wears, the photoreceptor surface becomes damaged, or the urethane properties become unstable over time. Cleaning performance may also degrade when the toner particles are spherical and thereby tend to roll under the cleaning blade nip.
Cleaning performance may be improved by adding acicular surface additives, for example, acicular titanium dioxide, during the blending of the toner particles. The acicular surface additive is not blended into the toner particles, but rather mixed in and loosely dispersed among the toner particles.
In addition, cleaning performance may be improved by lubricating the cleaning blade with various lubricating powders, for example, zinc stearate and graphite fluoride, to reduce surface forces on the cleaning blade. Lubrication can be achieved by dusting the cleaning blade with powders or coating the cleaning blade with a solution including the lubricating powders. Unfortunately, these lubricant powders do not remain adhered to the cleaning blade and create frictional forces that damage the blade edge, which inherently causes toner to get under the blade and create image defects.
There remains a need for a cleaning blade and lubricant for an electrophotographic printing device that minimizes toner particles from rolling underneath the cleaning blade, particularly spherical shaped toner particles.
The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments herein. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the present disclosure, since the scope of the present disclosure is best defined by the appended claims.
Various inventive features are described below that can each be used independently of one another or in combination with other features.
Broadly, embodiments of the present disclosure generally provide a cleaning blade lubricant comprising an acicular shaped lubricant.
In another aspect of the present disclosure, a cleaning blade for toner particles includes a surface and an acicular shaped lubricant on the surface.
In yet another aspect of the present disclosure, a method for improving the performance of a cleaning blade of an electrophotographic printing device includes the step of applying an acicular shaped lubricant to the cleaning blade.
Various embodiments of the present disclosure will be described herein below with reference to the following figures wherein:
The present disclosure provides a cleaning blade and lubricant suitable for use, for example, on a cleaning blade of an electrophotographic device and which lubricant reduces the probability of toner particles rolling on the photoconductor drum surface and underneath the cleaning blade.
To reduce surface forces and to improve residual toner cleaning off the photoreceptor, in an embodiment according to the present disclosure shown by
An acicular shape lubricant according to embodiments herein may also reduce the incidence of cleaning blade clogging and print defects compared with conventional cleaning blade lubricants, such as zinc stearate and graphite fluoride. In addition, the acicular shaped lubricant according to embodiments herein may reduce the tendency of the toner particles to roll under the cleaning blade.
The amount of acicular shaped lubricant applied to the cleaning blade may depend on the size and shape of the cleaning blade. The acicular shaped lubricant may be sufficient to completely cover the working edge of the cleaning blade prior to installing it against the photoreceptor.
In embodiments herein, the term “acicular” may refer to particles having irregular, slender, or a needle-like shape. Thus, the acicular shaped lubricant may be, for example, rice shaped, stick shaped, butterfly shaped, or bow tie shaped.
The particles of acicular shaped lubricant may be in length, for example, from about 0.25 to about 8.0 microns, or from about 0.5 to about 5.0 microns, or from about 1.0 to 3.0. The acicular shaped lubricant particles may have an aspect ratio (length/diameter), such as from about 4 to about 25, or from about 8 to about 18, or from about 10 to about 15.
In exemplary embodiments, the acicular shaped lubricant may be, for example, acicular carbon fiber, acicular fiber glass, acicular carbon nanotubes, and acicular magnesium fiber. In an exemplary embodiment, acicular titanium dioxide (acicular TiO2) may be the acicular shaped lubricant, though there may be more than one acicular surface additive used.
The acicular TiO2, may be, for example, acicular TiO2 sold by Titan Kogyo or Sangyo Kaisha, that comes in different shapes as shown in
Similar materials are supplied by Sangyo Kaisha. These materials have a stick like shape, but are larger than those offered by Titan Kogyo, as shown in
In a step 41, an acicular shaped lubricant can be applied to a cleaning blade. In exemplary embodiments, the acicular shaped lubricant may be, for example, those described above, though there may be more than one acicular surface additive used.
In exemplary embodiments, the acicular shaped lubricant can be applied to the cleaning blade by dusting the cleaning blade with the acicular lubricant prior to assembly in a cartridge. For example, a brush can be used to dust or brush the acicular shaped lubricant onto the cleaning blade edge that interfaces the photoconductor drum. As a further example, the blade edge may be dipped into a pile of dry acicular shaped lubricant to fully coat the blade edge.
In some embodiments, a solution including an acicular shaped lubricant can be employed. In such embodiments, the acicular shaped lubricant may be suspended in a solvent or alcohol based liquid and then applied to the cleaning blade by a syringe or a dropper. In other embodiments, the cleaning blade may be coated or dipped into a solution including the acicular shaped lubricant.
The aqueous or alcohol based liquid may be, for example, iso-propyl alcohol (IPA); engineered fluid Novec™ by 3M such as HFE7100, HFE7200, HFE7300 or performance fluid such as PF5060 by 3M.
The amount of acicular shaped lubricant in the alcohol based liquid may be, for example, from about 10 to about 40 parts by weight of the alcohol based liquid to about 1 part by weight of acicular shaped lubricant, or from about 12 to about 35 parts by weight of the alcohol based liquid to about 1 part by weight of acicular shaped lubricant, or from about 18 to about 25 parts by weight of the alcohol based liquid to about 1 part by weight of acicular shaped lubricant.
In a step 42, a portion (such as the edge or surface) of the cleaning blade having the acicular shaped lubricant can be operatively interfaced to the photoconductor drum, such as shown in
In a step 43, the foregoing portion (such as the edge or surface) of the cleaning blade having the acicular shaped lubricant can contact toner particles on the photoconductor drum.
In a step 44, toner particles contacted by the acicular shaped lubricant are prevented from passing under the cleaning blade and enabled to slide on the cleaning blade.
In view of the above, it was surprisingly discovered that the sole presence of an acicular surface lubricant on the cleaning blade helped to form a more robust dam in the cleaning blade nip that, in turn, prevents toner and larger additives from rolling under the cleaning blade, enabling a good cleaning performance.
Using an acicular shaped lubricant directly on the cleaning blade also allows the use of spherical toner particles, which are more stable and easier to manufacture than non-spherical toner particles. Additionally, enabling the cleaning of spherical particles improves the overall quality of the toner.
In addition, using an acicular shaped lubricant on the cleaning blade optimizes cleaning performance, instead of redesigning the cleaning blade or introducing an acicular shaped surface additive to the toner particle itself.
Furthermore, using an acicular shaped lubricant on the cleaning blade can be very cost effective, as it does not require adding an acicular titania additive to the toner which causes Bias Charge Roller (BCR) contamination due to excessively loose additives.
It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that 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.
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| Number | Date | Country | |
|---|---|---|---|
| 20140363212 A1 | Dec 2014 | US |
