Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...
Reexamination Certificate
2002-04-02
2004-05-11
Rodee, Christopher (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Post imaging process, finishing, or perfecting composition...
C430S106100, C430S106200, C430S108100, C430S108600
Reexamination Certificate
active
06733940
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a toner which can be used in an MICR (Magnetic Ink Character Recognition) system to produce characters which can be magnetically read, the magnetic toner usable in non-magnetic monocomponent developing systems such as electrophotographic printers and copying machines.
2. Description of Related Art
A magnetic ink character recognition (MICR) system is a system in which images are magnetized and read by a magnetic head, and was designed to efficiently conduct processes for prevention of forgery and falsification, and for identification and classification of bills, checks, negotiable instruments, tickets, etc. Magnetic images are not easily produced because offset printing is usually employed by using the magnetic ink. Although a heat sensitive transfer type printer may be employed as a small printer, characters other than MICR characters and graphic images could not be printed because such a printer was exclusively a monofunctional printer for printing only MICR characters. Therefore, simpler processes have been introduced, in which documents used in MICR systems, especially checks and bills, are produced by an electrophotographic system. Electrophotographic systems are roughly classified into two-component developing systems, magnetic monocomponent developing systems, and non-magnetic monocomponent developing systems; the two-component developing system is not deemed to be simple because a larger machine is used as compared with that for a monocomponent developing system.
Therefore, a magnetic or non-magnetic monocomponent developing system has lately been of major interest as a developing system for MICR.
The magnetic monocomponent developing system is a system in which developing properties are controlled by the balance between magnetic power on a developing sleeve and a charging amount of toner, and printing for MICR can be easily conducted by improving a general magnetic monocomponent toner containing a magnetic material to obtain images capable of being read by MICR. However, the images are satisfactory graphic images required for general documents at present.
On the other hand, as described in Japanese Patent Application, First Publication No. Hei 11-202546, the non-magnetic monocomponent developing system is a system in which toner is fed on a developing sleeve, forming a thin layer of toner on the developing sleeve by means of a layer controlling member, charging the toner, developing the electrostatic latent image with the toner by bringing it into contact with a photoconductor which bears the electrostatic latent image, and transferring the toner image onto paper. The non-magnetic monocomponent system is a system in which developing properties of the toner are controlled only by an amount of charge on the developing sleeve, and a general toner containing no magnetic material for non-magnetic monocomponent development cannot function as a toner for MICR. Therefore, first of all, it is necessary to mix a magnetic material in the toner. When a magnetic toner comprising a binder resin such as styrene/acrylate ester copolymer or polyester resin and 40 to 70% of a magnetic material such as magnetite obtained by the prior art is used as a toner for MICR, the magnetic material exerts an influence on the charging amount, resulting in phenomenons such as fogging and scattering of the toner around fine lines often occurring, compared with images formed by using the general toner for non-magnetic monocomponent developing. Therefore, such a phenomenon can cause reading errors in a reader sorter of a reader in a MICR system, making it impossible to realize good graphic images required for the documents. Since the surface of a developing sleeve of the non-magnetic monocomponent developing system is made of a soft material such as urethane rubber, there arises a problem in that the magnetic material produces scratches on the surface of the developing sleeve and the toner components accumulate at the scratched portion, and thus it is impossible to obtain normal images and the developing sleeve should be often replaced with a new one.
It has also been found that a toner having an angular shape produces scratches on the surface of the developing sleeve.
Since MICR documents slide in contact with the magnetic head, ten or more times during their use, the resistance against sliding friction is also important and the addition of various waxes in the toner for MICR is disclosed in Japanese Patent Application, First Publication No. Hei 6-282100, Japanese Patent Application, First Publication No. Hei 6-43689 and Japanese Patent Application, First Publication No. Hei 7-271085. Even if the resulting image has no drawbacks, a problem often arises in the magnetic reading process, and therefore, no toner for MICR has been developed which can be used in a printer for the non-magnetic monocomponent developing system.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a toner for MICR suitable for use in a printer for a non-magnetic monocomponent developing system, which does not produce scratches on a developing sleeve when used in the printer for a non-magnetic monocomponent developing system and has a resistance against sliding friction to a magnetic head, and also causes no reading errors because of proper signal strength and imparts satisfactory image characteristics (for example, with respect to image density and fogging).
To achieve the objects described above, a first aspect of the present invention is directed to a toner for MICR, which is employed in a non-magnetic monocomponent developing system of feeding a toner on a developing sleeve, forming a thin layer of the toner on the developing sleeve by means of a layer controlling member, charging the toner, moving the toner to a photoconductor which bears an electrostatic latent image, developing the electrostatic latent image with the toner and transferring the toner image onto paper, the toner comprising a binder resin, a magnetic material and a wax, wherein a BET specific surface area is within a range from 0.70 to 1.00 m
2
/g.
The effect of the first aspect of the present invention is that it becomes possible to provide a toner for MICR suitable for use in a printer for a non-magnetic monocomponent developing system, which does not produce scratches on a developing sleeve when used in the printer for the non-magnetic monocomponent developing system and has a resistance against sliding friction to a magnetic head, and also causes no reading errors because of proper signal strength and impart satisfactory image characteristics (for example, with respect to image density and fogging).
To achieve the objects described above, a second aspect of the present invention is directed to a toner for MICR for a non-magnetic monocomponent developing system, which is employed in a non-magnetic monocomponent developing system of feeding a toner on a developing sleeve, forming a thin layer of the toner on the developing sleeve by means of a layer controlling member, charging the toner, moving the toner to a photoconductor which bears an electrostatic latent image, developing the electrostatic latent image with the toner and transferring the toner image onto paper, the toner comprising a binder resin, a magnetic material, a wax and a silica deposited on the surface thereof, wherein a BET specific surface area is within a range from 0.95 to 1.30 m
2
/g, and the silica is a hydrophobic silica 1 having a BET specific surface area within a range from 100 to 300 m
2
/g and a hydrophobic silica 2 having a BET specific surface area within a range from 30 to 80 m
2
/g.
The effect of the second aspect of the present invention is that it becomes possible to provide a toner for MICR suitable for use in a printer for a non-magnetic monocomponent developing system, which does not produce scratches on a developing sleeve regardless of the angular shape of the toner when used in the printer for the non-magnetic monocomponent developing system and has rubbi
Fujiwara Akira
Terao Masamoto
Rodee Christopher
Tomoegawa Paper Co. Ltd.
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