JPH0380257A - Photosensitive toner - Google Patents

Abstract

PURPOSE:To enable triboelectric charging by stirring by microencapsulating a photosensitive resin which is solid at a specified temp. and a color source developing its color by a reaction with a developing material. CONSTITUTION:A photosensitive toner 100 has a core-shell structure and the core 300 contained in the shell 200 consists of a photosensitive resin which is solid at <=30 deg.C and a color source developing its color by a reaction with a developing material. When the photosensitive toner 100 is combined with a developing toner which reacts with the color source in the toner 100 to allow the color source to develop its color, an image is formed on an arbitrary recording medium. Since the strength of the photosensitive toner 100 is high, triboelectric charging by stirring is enabled and the charging mechanism of the toner is simplified. The reliability of an image forming device can be enhanced and the cost of the device can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a photosensitive toner whose physical properties change upon irradiation with light.

[Prior Art] Conventionally, an apparatus has been proposed that records an image on an arbitrary recording medium by electrostatically coating a photosensitive toner and a color developer toner onto an arbitrary recording medium, exposing and developing the image. There is.

According to this apparatus, compared to the conventional method of recording images using a photosensitive recording medium and an image-receiving sheet, consumables are used more effectively, so copying costs can be reduced.

[Problems to be Solved by the Invention] However, in this conventional device, the strength of the photosensitive toner is not sufficient, and when frictional charging by stirring is used as a method for charging the photosensitive toner, the photosensitive toner is destroyed. There was a problem with it.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a photosensitive toner that can be triboelectrically charged by stirring.

[Means for Solving the Problems] In order to achieve this object, the photosensitive toner of the present invention has three
It has a microcapsule shape that includes a photosensitive resin that is solid at temperatures below 0°C and a chromogen that develops color by reacting with a color developer.

C Effect] The photosensitive toner of the present invention having the above structure can be used in any recording medium by being combined with a developer toner that reacts with the chromogen contained therein to develop color from the chromogen. Form an image on top.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

FIG. 1 is an enlarged cross-sectional view of the photosensitive toner of the present invention. The photosensitive toner 100 is placed inside the outer shell 200 at a concentration of 30
It has a structure containing an inner core portion 300 made of a photosensitive resin that is in a solid state at temperatures below .degree. C. and a chromogen that develops color by reacting with a color developer.

As the photosensitive resin, polymerizable monomers and oligomers are suitable. Conventionally known monomers or oligomers generally exhibit a liquid phase at room temperature.
As a result of intensive studies to obtain a polymerizable component having a melting point of 150° C., it was found that a component containing a cyclohexyl ring, an isocyanate ring, or a urethane bond in its molecular structure can be used.

As the monomer or oligomer having a melting point within the range of 30 to 150°C, which can be used in the present invention, epoxy acrylate (m
p: 60°C), bisphenol A type epoxy resin (Mn
-2900) and methacrylic acid (mp: 90°C).

It also has a cyclohexyl ring in its molecular structure and a melting point of 30~
Hydrogenated bisphenol A type epoxy resin (Mn
3000) and methacrylic acid (MPNia 0°C).

It has an isocyanate ring in its molecular structure and has a melting point of 30-1
Tris 2-methacryloxyisocyanurate (
mp: 80°C), trimetaallylisocyanurate (m
p: 86°C). In addition, as a monomer or oligomer having a urethane bond in its molecular structure and having a melting point within the range of 30 to 150°C, urethane synthesized by the reaction of 4,4'-diphenylmethane diisocyanate and 2-hydroxyethyl acrylate Acrylate (mp: 90°C), urethane acrylate (m
p: 130°C). It also has a cyclohexyl ring and a urethane bond in its molecular structure, and has a melting point of 30~
Monomers or oligomers within the range of 150°C are also effective; examples include urethane acrylate (mp
: 150°C), urethane acrylate synthesized from the reaction of 1,4-cyclohexylene diisocyanate and 2-hydroxypropyl acrylate (mp: 110°C)
, 4.4' dicyclohexylmethane diisocyanate and 2-hydroxyethyl methacrylate (mp: 90° C.).

As a chromogen, 3.3-bis(P-dimethylaminophenyl)-6-dimethylaminophthalide, 3.3-bis(P-dimethylaminophenyl)phthalide, 3-(P
-triarylmethane compounds such as -dimethylaminophenyl)-3-(1,2-dimethylindol-3-yl)phthalide, diphenylmethane compounds such as 4゜4'-bisdimethylaminobenhydrin benzyl ether,
Xanthine compounds such as 3-dimethylamino-7-medoxyfluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-7-dibenzylaminofluoran, thiazine compounds such as benzoylleucomethylene blue, 3- Methyl-spiro-dinaphthopyran, 3
-Propyl-spiro dibenzobilane and other spiro compounds.

Known compounds commonly used as a photopolymerization initiator for polymerizing the photosensitive resin may be used, such as benzoin alkyl ether, benzophenone, Michler ketones,
Thioxanthone, acetophenone, etc. may be included, and anthraquinone, 5-nitrofluorene, etc. may be incorporated as a photosensitizing aid having the effect of broadening the sensitizing wavelength range of the photopolymerization initiator.

As the color developing substance that develops the color of the chromogen, acid clay,
Inorganic acidic substances such as activated clay, kaolin, zeolite, bentonite, P-cresol, P-octylphenol, P-cyclohexylphenol, P-phenylphenol, α-naphthylphenol, cumylphenol, P
- Substituted phenol compounds such as chlorophenol, phenol resin compounds such as phenol-formalin condensates, substituted phenol-formalin condensates, and metal salt-modified phenolic resin compounds obtained by modifying them with polyvalent metals such as zinc and nickel; P-butylbenzoic acid, P-hydroxybenzoic acid, 2,5-dihydroxybenzoic acid, salicylic acid, 5-tert-butylsalicylic acid 3,5-diter
Aromatic carboxylic acid compounds such as t-butylsalicylic acid and 3,5-di(α-methylbenzyl)salicylic acid, and metal salts of aromatic carboxylic acid compounds made from metal salts of these compounds with polyvalent metals such as zinc and nickel. Alternatively, the photosensitive toner having a microcapsule shape used in the present invention, which may be a mixture of an aromatic carboxylic acid compound and a polyvalent metal compound such as zinc acetate or zinc propionate, may be produced by a method known in the art. I can do it. For example, U.S. Patent No. 28004
57, the phase separation method from an aqueous solution as shown in the specification of 2800458, etc., Japanese Patent Publication No. 3g-19574,
Interfacial polymerization method as shown in the same town No. 42-446, Kaimei No. 42-771, etc., 1n-situ method by polymerization of monomers shown in Japanese Patent Publication No. 36-9168, Japanese Patent Application Laid-open No. 51-9079, etc. Melting and dispersion cooling method shown in British Patent No. 952807, equivalent specification No. 965074, etc.
US Patent No. 3111407, UK Patent No. 930422
Examples include the spray drying method shown in the specification of No. 1, etc., but are not limited thereto. In addition, as wall film forming materials, gelatin, gum arabic, starch, sodium alginate, ethyl cellulose, carboxyethyl cellulose, polyvinyl alcohol, polyethylene, polyamide, polyester, polyurethane, polyethyleneimine, etc. are used, but materials that allow sufficient light transmission are used. The material is more preferable.

FIG. 2 is a sectional view schematically showing an image forming apparatus using the photosensitive toner of the present invention.

The internal structure of the image forming apparatus 1 is roughly divided into a document table drive system that drives the document table 22 to expose the document 21, and a document table drive system that drives the document table 22 to expose the document 21.
a first developing system for developing an electrostatic latent image on the photosensitive drum 41 with a photosensitive toner 42 and a color developer toner 43; , a conveyance system that conveys an arbitrary recording medium 51, pressurizes the photosensitive toner 42, the color developer toner 43, and conveys the arbitrary recording medium 51.
It consists of a second developing system that performs development and recording on the recording medium 51 and a fixing system that fixes any recording medium 51 that has been developed and recorded.

A more detailed structure will be explained below with reference to FIG.

The document table drive system includes a document table 22, a drive wire 23 fixed to the document table, a drive pulley 24, and a drive motor 25.
Consisting of

The exposure system includes a light source 31 for irradiating light onto the original 22, a slit 32 for performing slit exposure, and a lens 33 for forming and exposing the reflected image of the original 22 onto the photosensitive drum 41.

The first development system includes a photoreceptor drum 41 that forms an electrostatic latent image by exposure, and a photosensitive toner developer 44 that develops the electrostatic latent image on the photoreceptor drum 41 along the rotational direction of the photoreceptor drum 41. , a color developer toner developer 45 , a cleaning unit 47 having a cleaning blade 46 for cleaning the photoreceptor drum 41 , a static elimination lamp 48 , four charging corotrons, and a color developer toner developer 45 , a cleaning unit 47 having a cleaning blade 46 for cleaning the photoreceptor drum 41 , a charge removal lamp 48 , four charging corotrons; It consists of an exposure heater 40 arranged inside a photoreceptor drum 41.

The transport system includes a cassette 52 that supplies an arbitrary recording medium 51.
, a conveyance roller 53 that conveys an arbitrary recording medium 51.

The second development system includes a pressure roller 61 for pressurizing the exposed photosensitive toner 42 and developer toner 43 to develop and record it on an arbitrary recording medium 51, and a development heater that heats the pressure roller 61. It consists of 62. Here, the photosensitive drum 41 is used as one pressure roller of the pressure mechanism. The fixing system can be used on any recording medium 5 that has been developed and recorded.
A thermal fixing device 71 and a paper ejection tray 72 for fixing the image on 1
Consisting of

Next, the overall operation of the present image forming apparatus will be explained with reference to FIG.

First, the original 21 is passed through the slit 32 by the light source 31.
light is irradiated on. The original image (tJJ&) is imaged and exposed by the lens 33 onto the charged photosensitive drum 41 to form an electrostatic latent image. This electrostatic latent image is first developed with photosensitive toner 42 supplied from a photosensitive toner developer 44 . In synchronization with the movement of the document table 22, the photosensitive drum 4.
1 rotates, and an electrostatic latent image for 21 sheets of originals is developed on the photoreceptor drum 41. After the photoreceptor drum 41 has the photosensitive toner 42 attached to its surface, the photoreceptor drum 41 is neutralized by a static elimination lamp and charged by a corotron. The entire surface is charged again and returns to the starting position.

At the same time, the document table 22 also returns to the starting position, and the document 21 is again irradiated with light from the light source 31, and the reflected image of the document is imaged and exposed onto the photoreceptor drum 41 with the photosensitive toner 42 that has been recharged, and is exposed to electrostatic latent light. An image is formed.

In this exposure, the photoreceptor drum 4 is simultaneously formed with an electrostatic latent image.
A reflected image of the document is formed on the photosensitive toner 42 adhering to the photosensitive toner 1 and is exposed to light. The inner core of the photosensitive toner 42 is heated to 30° C. or higher by the exposure heater 40, and its phase changes to a liquid state.

When the photosensitive toner 42 is exposed in this state, a latent image is formed depending on the degree of viscosity change of the photosensitive resin in the photosensitive toner 42 corresponding to the amount of exposure.

Thereafter, the electrostatic latent image is developed by the developer toner 43 supplied from the developer toner developing device 45 so as to be superimposed on the photosensitive toner 42 in the exposed area that was previously attached.

After development, the photosensitive toner 4 is deposited on any recording medium 51.
2. A process of developing and transferring the image formed by the developer toner 43 begins.

First, the cassette 52 is rotated in synchronization with the rotation of the photoreceptor drum 41.
An arbitrary recording medium 51 is supplied directly below the photoreceptor drum 41 via a conveyance roller 53 .

Here, in this embodiment, the photosensitive drum 41 is used as a pressure roller, and the pressure roller 61 is used only when the arbitrary recording medium 51 is present.
The nip pressure is applied between the photoreceptor drum 41 and the pressure roller 61 in cooperation with the photoreceptor drum 41 and the pressure roller 61.

An arbitrary recording medium 51 is passed between the nip between the photosensitive drum 41 and the pressure roller 61 configured as described above in synchronization with the rotation of the photosensitive drum 41.

When passing between the photoreceptor drum 41 and the pressure roller 61, the photosensitive toner 42 is heated by the developing heater 62 via the pressure roller 61, and the photosensitive toner 42 in the unexposed area is in a liquid state. The photosensitive toner 42 in the exposed area is cured by a photopolymerization reaction and remains in a solid state, so the photosensitive toner 42 in the unexposed area on the photoreceptor drum 41 is destroyed by pressure and the chromogen is released. It contacts and reacts with the color developer toner 43 to develop color. At the same time, the colored chromogen is held in the developer toner 43 layer and transferred onto an arbitrary recording medium 51 under pressure.

After transferring the photosensitive toner 42 and developer toner 43, the surface of the photosensitive drum 41 is cleaned by a cleaning blade 46 in a cleaning unit 47, neutralized by a static elimination lamp 48, and uniformly re-charged by a charging corotron 49. and return to the initial state.

On the other hand, the image transferred onto the arbitrary recording medium 51 is fixed on the arbitrary recording medium 51 by the thermal fixing device 71, and the arbitrary recording medium 51 is discharged to the paper ejection tray 72 by the conveyance roller 53, and the entire recording process is completed. ends.

In the above embodiment, an example was shown in which the photoreceptor drum 41 is of a type that can also be used as a pressure roller. The attached exposed area photosensitive toner 42 and color developer toner 43 are transferred at once onto an arbitrary recording medium 51 using a transfer corotron, and after pressure development is performed by the pressure development mechanism, fixation, It may also be a mechanism for ejecting paper.

[Experimental Example: A mixture of 9 parts of Cotris 2-methacryloxyethyl isocyanurate, 7 parts of crystal violet lactone, and 3 parts of diethylthioxanthone in 20 parts of methylene chloride was mixed with 200 parts of water in which a cationic or nonionic surfactant and 1 part of gelatin were dissolved. and emulsified and dispersed with a homomixer under heating at 60° C. to form an oil-in-water emulsion with oil droplets of 2 to 6 μm.

Further, stirring was continued at 60° C. for 30 minutes, and methylene chloride was distilled off to give an average particle size of 10 μm. To this was added 20 parts of water in which 1 part of gum arabic was dissolved, and while slowly cooling, aqueous ammonia was added to adjust the pH to 11 or higher, thereby completing the encapsulation.

Thereafter, the capsule dispersion was dried using a spray dryer to obtain a photosensitive toner.

When the photosensitive toner thus obtained was loaded into the image forming apparatus and an actual copying operation was performed, a clear image was obtained on plain paper.

In this example, the case where one type of photosensitive toner is used is described, but three types of photosensitive toners are used, each of which is sensitive to three independent wavelengths of light and develops colors of yellow, magenta, and cyan. Needless to say, a color image can be obtained by doing this.

[Effects of the Invention] As is clear from the detailed description above, according to the present invention, since the strength of the photosensitive toner is high, frictional charging by stirring is possible, and the charging mechanism of the photosensitive toner is simplified. , it becomes possible to improve the reliability of the image forming apparatus and reduce the cost of the apparatus.

[Brief explanation of drawings]

1 to 2 show embodiments embodying the present invention. FIG. 1 is an enlarged cross-sectional view of a photosensitive toner, and FIG. 2 is an image formation using a photosensitive toner. FIG. 2 is a cross-sectional view schematically showing the device. In the figure, 42,100 is a photosensitive toner.

Claims (1)

[Claims] 1. A photosensitive toner in which a photosensitive resin that is in a solid state at 30° C. or lower and a chromogen that develops color by reacting with a color developer are encapsulated.