JPH04318548A - Image forming device - Google Patents

Abstract

PURPOSE:To eliminate wasteful use of developer toner and to provide an image recording where weather resistance is inconspicuous by applying the developer toner only on the positions of images and characters formed on an arbitrary recording medium, in the image forming device utilizing a photosensitive and pressure sensitive recording medium. CONSTITUTION:Micro capsules carried in the photosensitive and pressure sensitive recording medium K are hardened and black body is heated by exposure according to image information from an original. By having the developer toner carried in the black body thus fused, the photosensitive and pressure sensitive recording medium K is selectively coated with the developer toner. The micro capsules carried in the photosensitive and pressure sensitive recording medium K are broken, the developer toner transferred on the photosensitive and pressure sensitive recording medium K are fixed to the arbitrary recording medium, and the image is formed.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an image forming apparatus.
In particular, the present invention relates to an improvement in an image forming apparatus that develops color by pressure-developing a photosensitive pressure-sensitive recording medium and a color developer toner.

0002

BACKGROUND OF THE INVENTION Conventionally, color developers have been dispersed as ultrafine particles in an aqueous solvent. A color developer sheet is produced by adding an adjusted binder, additives, etc. to this color developer and applying the mixture to paper. Image forming apparatus technology using this color developer sheet is disclosed in Japanese Patent Application Laid-Open No. 58-88739, Japanese Patent Application Laid-Open No. 59-30537, and Japanese Patent Application Laid-Open No. 59-137.
It is described in Publication No. 944, etc. Image forming technology here refers to two or more components isolated from each other that are released from isolation by a physical external force such as a pressure or temperature change, and react with each other to produce an optical change.
Refers to all technologies that cause changes in the absorption area or intensity of light and record in response to external forces.

As an image forming technique, for example, a light-sensitive pressure-sensitive recording medium in which microcapsules whose mechanical breaking strength changes with light irradiation are supported on an arbitrary medium, and a color developer sheet are overlapped and pressure is applied. Once established, microcapsules with different mechanical fracture strengths undergo selective collapse. The colorless or slightly colored dye or dye precursor contained in the crushed microcapsules reacts with a substance capable of coloring the dye (i.e., dye receptor or color developer), and the colorless or slightly colored dye or dye precursor is reacted with a color developer sheet. There is an image forming technology that forms a visible image on top.

[0004] Similar to this image forming technology, as an image forming means for an arbitrary recording medium, a powdered color developer is electrostatically flung onto a color developer sheet using an arbitrary recording medium as a base material. There is an image forming technique in which an image is formed, a photosensitive pressure sensitive recording medium is superimposed on the color developer sheet, and the image is fixed under pressure. As a specific example of such image forming technology, conventionally, an electrode is placed on the back side of a carrier for developer toner, which is a powder color developer, to generate an electric field, and an arbitrary recording medium is passed through this state. , a color developer was electrostatically ejected onto an arbitrary recording medium. Therefore, the developer toner is applied onto the arbitrary recording medium by the length (width) of the developer toner carrier. Therefore, the color developer toner is applied to the entire surface of the arbitrary recording medium, and the color developer toner is also applied and fixed to the portions of the document where characters and images are not formed.

[0005]

[Problems to be Solved by the Invention] However, when the color developer toner is electrostatically applied to the non-image-forming areas of the document, that is, to the white areas, the color developing function, which is the original function of the color developer toner, is lost. It is fixed on the recording medium without being developed. This is a waste of developer toner and the output image (
(hard copy) The cost per copy will also increase. Furthermore,
The developer toner fixed on any recording medium that does not participate in color development changes color when exposed to light or the atmosphere. Discoloration of the developer toner reduces image contrast and impairs the shelf life of the developer toner layer formed on any recording medium.

[0006] Therefore, a selective coating method was devised in which developer toner is applied only to the image area. However, in this method, the process of curing the microcapsules by exposing the photosensitive and pressure-sensitive recording medium to light and the process of applying the color developer that develops the color are separate, and the area where the color developer is present and the microcapsules are separated. It was very difficult to align the parts with the uncured parts. In other words, there is a misalignment between the area where the color developer is applied and the area where the microcapsules are crushed and the dye, etc. flows out, and not only is there a color developer that does not contribute to color development, but the image is distorted and difficult to see. It had become.

[0007] In order to solve the above problems, the present invention has the following features:
The purpose of the present invention is to apply developer toner only to the positions of images and characters to be finally formed on an arbitrary recording medium, eliminate waste of developer toner, and provide an image forming device with good weather resistance. .

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention selectively hardens the microcapsules by selectively exposing a photosensitive pressure-sensitive recording medium carrying microcapsules to light corresponding to the image information of the original. pressure-sensitive recording medium,
A developer toner that develops color from a dye or dye precursor encapsulated in uncured microcapsules is propelled by an applied electric field and pressure developed while the dye is brought into contact with the dye or dye precursor.
In the image forming apparatus that obtains an output image by pressure-transferring the image information onto a recording medium, the light-sensitive and pressure-sensitive recording medium has microcapsules supported on the surface of a light-transmitting base material, and the light-transmitting substrate has microcapsules facing the microcapsule side. A photoheating element that generates heat when irradiated with light is disposed, a developer toner is supported on the photoheating element, and light containing image information of the document is projected from the back side of the light-transmitting substrate to generate the image information. simultaneously irradiating a photosensitive pressure-sensitive recording medium and a light heating element, selectively exposing and curing a portion of the microcapsule corresponding to a non-image information portion of the document, and generating heat in the selectively irradiated portion of the heating element; The color developer toner is melted and fused to the heating element, and only the color developer toner in the portion corresponding to the image information portion of the document that is not reached by the selective irradiation light is flown and adhered to the photosensitive pressure sensitive recording medium. It was designed to encourage.

[0009]

According to the present invention, light containing the image information of the original passes through the photosensitive pressure-sensitive recording medium, and simultaneously hardens the microcapsules by selective exposure and generates heat by selectively irradiating the photoheating element. Due to this heat generation, the color developer toner previously supported on the photoheating element is fused to the photoheating element. On the other hand, the developer toner in the portion of the photoheating body that is not irradiated with the selective exposure light flies toward the microcapsule (that is, toward the photosensitive pressure-sensitive recording medium) due to the electrostatic force of the electric field, and adheres to the microcapsule. The microcapsules in the portions of the microcapsules to which the color developer toner is attached are not selectively exposed, and are therefore not hardened. When pressure development is performed in such a state, the uncured microcapsules are crushed and colored by the developer toner. In other words,
The developer toner in the area corresponding to the microcapsules to be crushed is attached to the photosensitive pressure-sensitive recording medium, and the other developer toner is not attached. Therefore, during pressure development, no other developer toner remains on the recording medium.

0010

Embodiments Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. As shown in FIG. 1, the image forming apparatus M includes an exposure device 10, a developing device 20, a transfer device 30,
It is composed of a heat fixing device 40 and the like. A document table 2 is arranged on the top surface of the housing 1, and a document 3 is placed on the bottom side of the document table 2.
is now supported. The document table 2 supporting the document is driven laterally by a drive means (not shown).

The exposure device 10 is disposed below the document table 2, and the light emitted from the light source 4 is emitted directly or through a reflecting mirror 5.
and reaches the document 3. The light reflected by the original 3 passes through the filter unit 6 and reaches the photosensitive pressure sensitive recording medium K disposed below and the black body 18 according to the gist of the present invention. The photosensitive and pressure sensitive recording medium K is wound and housed in a cartridge 7 disposed on the right side, and is wound onto a take-up roller 12 via guide rollers 8 and 9 and a pressure fixing roller 11. A charger 13 is arranged near the black body 18 on the travel path of the photosensitive pressure sensitive recording medium K.

Here, the photosensitive and pressure sensitive recording medium K is shown in FIG. 2(A).
The explanation will be based on. As shown in FIG. 2(A), the photosensitive and pressure sensitive recording medium K is colored by reacting with a color developer toner T on the surface of a plastic film base material 31 made of transparent polyethylene terephthalate, polypropylene, etc. that transmits visible light. Photocurable microcapsules 32 containing a leuco dye or a dye precursor such as crystal bioretolactone or 3-diethylamino-7-chlorofluoran are supported. In the microcapsules 32, the amount of curing of the encapsulated photocurable resin changes depending on the amount of light irradiation,
Its mechanical breaking strength changes.

The developing device 20 is disposed on the lower right side of the housing 1, and a developer toner T is stored inside the toner case 14. A supply roller 15 is disposed inside the toner case 14, and the supply roller 15 causes the developer toner T to be carried on a roller-shaped carrier 16 disposed on the left side. The supply roller 15 is preferably made of an elastic and soft material, such as a sponge roller, in order to supply the developer toner T without crushing it. The surface of the carrier 16 is roughened in order to improve the transport efficiency of the color developer toner T. A blade 17 for adjusting the thickness of the developer toner T attached to the outer peripheral surface of the supply roller 15 is disposed near the upper side of the supply roller 15 . The blade 17 is preferably made of a harder material than the material of the supply roller 15.

A drum-shaped black body 18 constituting the transfer device 30 is disposed at the upper left of the carrier 16 and at a position where the reflected light reaches. The black body 18, which is a light heating element serving as a transfer means, is a drum made by dispersing an infrared absorbing dye and pigment including a black dye and pigment such as carbon black in a resin, or a drum made by dispersing an infrared absorbing dye and pigment including a black dye and pigment such as carbon black. It is constructed by forming a release layer on top of the coating. A back electrode 19 for positively charging the black body 18 is disposed inside the black body 18 at a position facing the carrier 16, and the back electrode 19 is connected to the power supply 2.
Connected to the positive terminal of 1. A toner collection blade 22 is arranged on the left side of the black body 18, and the remaining developer toner T that has not been transferred to the photosensitive and pressure sensitive recording medium K is peeled off by this blade 22, and the peeled developer toner is removed. is housed in the toner collection case 23.

A cassette 27 containing stacked recording media S is disposed on the left side of the housing 1, and the recording media S are taken out one by one from the top by a suction cup device (not shown), and are moved along a guide plate 27a to the pressure fixing roller 11. Sent. Heat fixing device 40
A heat fixing belt 25 having a built-in heater 24, and a heat fixing belt 26 disposed opposite to this heat fixing belt 25.
The recording medium S passes between these heat fixing belts 25 and 26.

Next, the operation and configuration of the parts related to the gist of the present invention will be explained. First, the operation of applying the color developer toner T according to the gist of the present invention to the photosensitive pressure-sensitive recording medium K will be explained based on FIG. 2(A). As shown in FIG. 2(A), light containing the image information of the original 3 (see FIG. 1) is applied to the base material 3.
The light is irradiated from one side to harden the microcapsules 32 in the portion corresponding to the image information, and the light transmitted through the photosensitive and pressure sensitive recording medium K reaches the black body 18. Then, the black body 18 generates heat due to the irradiation with light, and the developer toner T is fused onto the black body 18 .

[0017] The heat generation is largely due to infrared rays. Further, the fusion of the developer toner T to the black body 18 is affected by the intensity of the irradiated light, and fusion to the black body 18 occurs only when irradiated with light covering the entire visible light region. The developer toner T1 that is not fused to the black body 18 is attracted to the photosensitive pressure sensitive recording medium K by the electric field formed by the charger 13, flies and adheres to the photosensitive pressure sensitive recording medium K, and is conveyed together with the photosensitive pressure sensitive recording medium K.

On the other hand, the developer toner T2 fused to the black body 18 is conveyed as the black body 18 rotates. In this case, the material melts and becomes liquid when it is irradiated with light, but it solidifies as time passes during transportation. black body 18
Since a release agent is applied to the top layer of the color developer toner T, the release effect is not exhibited when the color developer toner T is fused, but when solidified, the color developer toner T is easily separated from the surface of the black body 18. Become. Therefore, the developer toner T2 fused onto the black body 18 can be scraped off by the scraper-like toner collection blade 22. The developer toner T
2 is scraped off, the color developer toner T is attached again to the black body 18, and the same operation as described above is repeated.

The color developer toner T used in the present invention is mainly composed of a dye receptor that develops color by reacting with a dye or a dye precursor, such as natural clay minerals such as acid clay, bentonite, and attapulgite; Organic acids and their esters such as tannic acid, gallic acid, propyl gallic acid ester, etc.; phenolic resins, maleic acid resins, phenol-acetylene resins, condensation polymerization of carboxylic acids having at least one hydroxyl group with formaldehyde, etc. Acidic polymer; metal salts of aromatic carboxylic acids such as zinc salicylate, tin salicylate, zinc 2-hydroxynaphthoate, zinc 3,5-di-t-butylsalicylate, zinc 3,5-di(α-methylbenzyl)salicylate, etc. ; Examples include metal salt-modified phenolic resin compounds modified with polyvalent metals such as zinc and nickel.

When the developer toner T is applied to the photosensitive and pressure sensitive recording medium K and fixed to the recording medium S under pressure, the developer toner T is reliably applied to the recording medium S. Since the image is not fixed on the recording medium S and remains on the photosensitive and pressure sensitive recording medium K side, gaps occur in the image on the recording medium S. Therefore,
A material is mixed with the color developer, which is a dye receptor, in order to impart pressure fixing performance that allows it to adhere only to the recording medium S side. The pressure fixing performance of the color developer toner T to the recording medium S is related to the entanglement and adhesiveness of its constituent components, and by mixing wax and adhesive with good compatibility and adhesiveness with the color developer. , pressure fixing performance can be improved. The color developer component and the pressure fixing component are melt-kneaded and pulverized, and if necessary, classified to form one particle, forming a color developer toner T having a volume average particle diameter of 5 to 50 μm. .

The light source 4 serving as the exposure means is preferably a light source in the visible light range capable of faithfully reproducing the image of the original 3, such as a halogen lamp, a tungsten flood lamp, or a halogen lamp.
Light sources that emit visible light such as metal halide lamps, lasers, and LED arrays are suitable. The role of the light source is to have enough light to accurately reproduce the color of the original image and completely cure the microcapsules 32 on the photosensitive and pressure sensitive recording medium K, and to provide the black body 18 with light in the entire visible light range. When providing light, it is necessary that the amount of light is sufficient to generate heat.

Further, as shown in FIG. 2(B), the pressure fixing roller 11 crushes the microcapsules 32 to cause the encapsulated dye to flow out, and selectively applies the dye to the portions where the uncured microcapsules 32 are present. The dye precursor is caused to develop color by interacting with the applied developer toner T, and the developer toner T impregnated with the developed dye precursor is transferred from the photosensitive and pressure sensitive recording medium K to the recording medium S. , the recording medium S is fixed under pressure. The pressure fixing roller 11 is formed by two cylindrical rollers, and an auxiliary roller (not shown) applies the pressure necessary for pressure fixing so as to support the two rollers.

By passing the recording medium S through the thermal fixing device 40 and heating it, the developer toner T is firmly fixed onto the recording medium S. The main parts of this embodiment are as described above. Next, the general operation of the image forming apparatus of this embodiment will be explained. The photosensitive and pressure sensitive recording medium K supplied from the cartridge 7 undergoes an image forming process while being transported by transport rollers 8 and 9 and a take-up roller 12.

First, a positive surface potential is applied to the surface of the photosensitive pressure sensitive recording medium K by the charger 13. In synchronization with this, the light from the light source 4 and the light from the reflecting mirror 5 are focused on the original 3, and the reflected light from the original 3 passes through the filter unit 6, the photosensitive and pressure sensitive recording medium K, and the color developer toner T. The light passes through and irradiates the surface of the black body 18. Since the light that irradiates the original 3 has a certain width, the light that exposes the photosensitive and pressure sensitive recording medium K also has the certain width. At the same time that the original 3 is conveyed to the document table 2, the photosensitive and pressure sensitive recording medium K is also conveyed to the charger 13.
Exposure is started over a certain width from the portion to which the surface potential is applied. The image information of the document 3 exposed through the filter unit 6 is exposed from the transparent base material 31 side of the photosensitive and pressure sensitive recording medium K, hardens the microcapsules 32, and at the same time passes through the developer toner T. So, black body 1
8 is also exposed.

The developer toner T is triboelectrically charged in the developing device 30, and the amount of the developer toner T attached to the carrier 16 is regulated by a blade 17 on the supply roller 15. The amount of developer toner T that is adhered to the carrier 16 and conveyed limits the amount of the color developer toner T that is adhered to and conveyed to the black body 18 . The developer toner T conveyed onto the carrier 16 is transferred to the black body 18
The back electrode 19 is located at a position opposite to the carrier 16.
Since a positive potential is applied to the black body 18, the negatively charged developer toner T flies toward the black body 18 along the electric field. The developer toner T uniformly applied onto the black body 18 is transferred onto the light and pressure sensitive recording medium K according to the image information at the transfer portion where the light and pressure sensitive recording medium K and the black body 18 are closest. be done. In the transfer area, the image information is simultaneously transmitted through the photosensitive pressure-sensitive recording medium K and the developer toner T to expose the black body 18, and when the reflected light from the white portion of the document 3 is exposed to the black body 18, , the black body 18 generates heat and fuses the developer toner T. The developer toner T remaining on the black body 18 is conveyed as is, scraped off from the black body 18 by a toner collection blade 22, and stored in a toner collection case 23.

The developer toner T adhering to the photosensitive and pressure sensitive recording medium K is overlapped with the recording medium S by the pressure fixing roller 11 and when pressure is applied, it is transferred and fixed onto the recording medium S. . The microcapsules 32 that have been hardened by light irradiation are not crushed, and the microcapsules 32 that are not irradiated with light are crushed by the pressure fixing roller 11, and the encapsulated dye precursor flows out, resulting in photosensitive and pressure sensitive recording. Color developer toner T attached to medium K due to electrostatic force
The dye precursor bleeds into the dye and develops color. As a result, it appears to the observer's eyes that the developer toner T has developed a color. The transfer rate of the color developer toner T to the recording medium S largely depends on the wettability of the surface of the photosensitive pressure-sensitive recording medium K and the recording medium S of the color developer toner T, and also depends on the properties of the fixing component. 1
00% transfer possible. The image formed on the recording medium S is fixed at 120 degrees by a thermal fixing device 40 in order to obtain strong fixation.
When heat is applied at a temperature of 180°C to 180°C, an image output with a glossy surface can be obtained.

The image obtained in this way has good storage stability against light and does not make discoloration noticeable because the part of the microcapsule 32 that is not crushed, that is, the white part, is not coated with the developer toner T. This allows you to obtain clear images. In this embodiment, a case has been described in which the photosensitive pressure-sensitive recording medium K is positively charged and the color developer toner T is negatively charged, but these polarities may be reversed.

[0028]

As explained above, according to the present invention, the photosensitive pressure sensitive recording medium and the light heating element are simultaneously irradiated to simultaneously selectively cure the microcapsules and generate heat from the light heating element.
Since the color developer toner on the photoheating element is selectively fused to prevent it from flying to the microcapsule side, only the color developer toner involved in color development adheres to the microcapsule. Therefore, the developer toner, which is unrelated to color development, does not adhere to the photosensitive pressure sensitive recording medium, so that no color change occurs and waste of the developer toner can be avoided.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an image forming apparatus to which the present invention is applied.

[Fig. 2] (A) is a diagram illustrating a state in which developer toner on a photoheating element that is not irradiated with light flies to a photosensitive and pressure-sensitive recording medium due to electrostatic force, and (B) is a diagram illustrating a state in which microcapsules are crushed. FIG.

[Explanation of symbols]

3... Original 4... Light source 10... Exposure device 13... Charger 16... Carrier 18... Black body (light heating element) 19... Back electrode 20... Developing device 30... Transfer device 31... Plastic film base material (light transmitting base material) )32...
Microcapsule 40...Heat fixing device K...Photosensitive and pressure sensitive recording medium S...Recording medium T...Developer toner

Claims (1)

[Claims] Claim 1: A photosensitive pressure sensitive recording medium carrying microcapsules is selectively exposed to light corresponding to the image information of a document to selectively harden the microcapsules, and the microcapsules encapsulated in the uncured microcapsules are encapsulated in the photosensitive pressure sensitive recording medium. In an image forming apparatus that transfers the image information to a recording medium under pressure to obtain an output image by carrying out pressure development in a state in which a developer toner that causes a dye or a dye precursor to develop color is caused to fly by an applied electric field and are brought into contact with each other. , the photosensitive pressure sensitive recording medium is
Microcapsules are supported on the surface of a light-transmitting base material,
A photoheating element that generates heat when irradiated with light is disposed opposite to the microcapsule side, a developer toner is carried on the photoheating element, and image information of the document is included from the back side of the light-transmitting base material. The light-sensitive pressure-sensitive recording medium and the photoheating element are simultaneously irradiated with light, and the portion of the microcapsule corresponding to the non-image information portion of the document is selectively exposed and cured, and the heat generated by the selective irradiation is The color developer toner is melted and fused to the heating element by generating heat in the body part, and only the color developer toner in the portion corresponding to the image information portion of the document that is not reached by the selective irradiation light is exposed to the light. An image forming apparatus characterized in that the image forming apparatus is configured to cause flying adhesion to a pressure-sensitive recording medium.