Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Reexamination Certificate
2001-09-14
2003-07-08
Chapman, Mark A. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Radiation-sensitive composition or product
C399S159000
Reexamination Certificate
active
06589700
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an indirect transfer type image recording apparatus and an indirect transfer type image recording method in which a toner image formed on an image carrier is transferred to a recording medium or an intermediate transferor so as to record an image; and relates to an image carrier for use in such an image recording apparatus and such an image recording method. Particularly, the present invention relates to an image recording apparatus and an image recording method using electrophotographically recording technology, electrostatically recording technology, ionography, magnetography, etc., and an image carrier for use in such an image recording apparatus and such an image recording method.
2. Description of the Related Art
Conventionally, in such an indirect transfer type image recording technique, differently from an ink-jet printer or the like in which an image is recorded directly on a recording medium such as recording paper or the like, a toner image is first formed on an image carrier. The toner image formed on the image carrier is transferred to recording paper or the like. The transferred toner image is fixed to obtain a recorded image. Then, after the toner image is transferred to the recording medium such as recording paper or the like, residual toner on the image carrier is generally recovered and abolished by cleaning means. For example, in an electrophotographic image recording apparatus, an image is recorded by a charging step, an exposing step, a developing step, a transferring step, a fixing step, and a cleaning step. In the charging step, the surface of an image carrier having a photosensitive layer in the surface is charged uniformly. In the exposing step, the charged surface of the image carrier is irradiated with image light so that an electrostatic latent image is formed. In the developing step, toner is made to adhere to the electrostatic latent image so as to form a toner image. In the transferring step, the toner image is transferred to a recording medium. In the fixing step, the toner image on the recording medium is fixed. In the cleaning step, residual toner on the image carrier in the transferring step is removed. In the cleaning step of these steps, a rubber blade or a brush having flexibility is pressed against the surface of the image carrier so as to recover the residual toner on the surface of the image carrier, and the recovered toner is accumulated in a recovery vessel and abolished periodically.
In such an image recording apparatus, it is necessary to always detect or measure the quantity of recovered toner accumulated in the recovery vessel so as to abolish the toner or exchange the recovery vessel before the recovery vessel is full of the toner. In addition, if the image recording apparatus is miniaturized so that a large space for installing the recovery vessel cannot be ensured, the inside of a drum-like image carrier may be used as a space for recovering toner. In such a case, the time to exchange the image carrier has to be established in accordance with the quantity of recovered toner. Further, reuse of recovered toner has proceeded from the point of view of environmental protection. However, the reuse of recovered toner involves a lot of problems such as a problem of separation, a problem of energy for conveyance and reuse, a problem of a recovery method and a storage place, and so on.
As means to solve such problems, the following means have been considered. (1) First means is to improve the transfer efficiency with which a toner image is transferred to a recording medium. If the transfer efficiency to the recording medium is improved, residual toner on the image carrier is reduced correspondingly. Thus, the quantity of toner to be recovered and disposed of is also reduced. (2) Second means is to recover residual toner from the image carrier and return the residual toner to the developing means so as to reuse the toner for development. If all the recovered toner is reused, it is not necessary to abolish the toner. (3) Third means is to solve disadvantage caused by residual toner without cleaning the image carrier. Thus, it is not necessary to recover the residual toner by cleaning, and it is expected that waste toner is prevented from being produced.
As the first means (1) to improve the transfer efficiency, the following techniques have been proposed.
(a) In the technique disclosed in JP-A-56-126872, the area where an electric field is formed for transfer is increased to improve the transfer efficiency.
(b) In the technique disclosed in JP-A-58-88770 or JP-A-58-140769, an alternating electric field is formed in a transfer position. This alternating electric field applies force to toner on an image carrier so as to vibrate the toner. Thus, separation of the toner from the image carrier is accelerated.
(c) In the technique disclosed in JP-A-52-126230, ultrasonic waves are radiated to an image carrier in a transfer position so as to generate vibrations. Thus, the adhesive force of toner grains is reduced.
(d) In the technique disclosed in JP-A-2-1870, JP-A-2-81053, JP-A-2-118671, JP-A-2-118672, or JP-A-2-157766, strippable particulates of silica or the like are contained in a developer. The particulates are interposed between toner and a photosensitive body. Thus, the adhesive force between the toner and the photosensitive body is reduced so that the transfer efficiency of the toner is enhanced.
(e) In the technique disclosed in JP-A-1-134485, transparent and colorless toner is made to adhere to a latent image formed on an image carrier, and colored toner is further put thereon to adhere thereto. Then, development is carried out. In a toner image formed thus, approximately 100% of the colored toner is transferred.
Although each of the disclosed techniques (a), (b) and (c) shows the effect of improvement of the transfer efficiency, a certain degree of toner still stays behind in the image carrier after transfer. Therefore, those techniques are not satisfactory to reduce waste toner.
On the other hand, in the disclosed technique (d), it is necessary to add an adequate quantity of strippable particulates to the developer, and coat toner with the strippable particulates uniformly. Actually, however, it is difficult to coat all the toner with the strippable particulates uniformly. It is therefore impossible to eradicate the existence of toner coated insufficiently. In addition, even if all the toner is coated with the strippable particulates uniformly, the strippable particulates are free from the toner due to various stresses such as stirring, layer thickness regulation, and so on, given thereto in a developing machine. Therefore, to keep the toner coated with the strippable particulates uniformly, it is necessary to realize a developing machine which gives no stress to the toner. Further, since it is necessary to add a large quantity of strippable particulates, the strippable particulates may adhere to the toner surface or the carrier surface due to use for a long term so that the electification property of the developer may be degraded, or the free strippable particulates may be flocculated. Thus, the flowability of the developer may be lowered to cause uneven development. In addition, the toner to which a large quantity of strippable particulates have been added is rich in flowability so that a toner image is disarranged easily when the toner image abuts against a recording medium at the time of transfer. Thus, such a phenomenon that an image is disarranged due to transfer is also apt to be produced.
Further, in the disclosed technique (e), a large quantity of transparent and colorless toner stays behind after a toner image is transferred. Unless the transparent and colorless toner is cleaned and removed before a next image is formed, the surface of the image carrier cannot be made uniform. It is therefore necessary to recover and abolish the transparent and colorless toner by use of a cleaning unit. Thus, the problem to reduce waste toner cannot be solv
Kiyama Tadashi
Maruyama Kazuo
Nishimura Shigeki
Tsutsumi Yasuyuki
Yamanoi Kazuya
Chapman Mark A.
Fuji 'Xerox Co., Ltd.
Morgan & Lewis & Bockius, LLP
LandOfFree
Image carrier and apparatus and method for recording image... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image carrier and apparatus and method for recording image..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image carrier and apparatus and method for recording image... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3034674