JPH10166651A - Image forming device - Google Patents

Abstract

(57) [Problem] To provide an image forming apparatus in which output light from a plurality of light emitting elements does not become stray light and the image quality of an output image formed therefor can be improved. An exposure head (20) that moves and scans in one direction in close contact with the surface of a microcapsule paper (37) has a substrate (1) carrying a large number of LEDs (7, 8, 9) that respectively emit RGB light, The mask 13 in which the pinholes 12 are formed at the positions respectively corresponding to the positions are integrally fixed by a mask holding member 14. The separation wall 2 is formed integrally with the mask holding member 14, and the separation wall 2 prevents light emitted from each LED from being mixed with each other. For this reason, from the pinhole 12 of the mask, the corresponding L
Only the output light of the ED is emitted to the outside, and generation of stray light that becomes unnecessary background light is prevented. For this reason, the image quality of the formed image is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of exposing a photosensitive recording medium on which a latent image of image information is formed by exposure to light to expose the image information by development with an image forming light corresponding to the image information. More particularly, the present invention relates to an image forming apparatus that exposes image forming light using a plurality of light emitting elements.

[0002]

2. Description of the Prior Art U.S. Pat.
No. 399209 discloses that a photosensitive layer having microcapsules containing a photosensitive substance in an internal phase is exposed to radiation in an image-like manner, and a uniform rupture force is applied, whereby the microcapsules rupture and the internal phase substance is imaged. Is described. Exposure changes the mechanical strength of the microcapsules to form an exposure latent image, and when pressure is applied, capsules with low mechanical strength (capsules that have not been cured or softened) are destroyed and color materials, etc. Is discharged and development is performed.

[0003] This image forming system is a completely dry system and has a great advantage because it does not depend on a wet developing solution to generate an image. An imaging color former, such as a nearly colorless color former, is usually encapsulated in microcapsules. When the microcapsules are broken, the color-generating substance (color-forming agent) as a coloring material reacts with the developing substance to form a color image.

In the embodiment described in the referenced patent, the microcapsules were exposed to the image, usually through a nip between a pair of cylindrical calendering (glazing) rollers. The microcapsule paper is broken by passing.

[0005] Usually, high pressure and large glazing rollers are used to develop microcapsule paper. Even with fairly precise metal polishes, the surface is not flat.
If one roller simply rests on the other, the surfaces of both rollers are not in contact over their full width. By applying pressure to the rollers, the uneven surface or irregularities of the surface are smoothed and provide a uniform line of contact between the rollers. High pressure and large rollers are required to achieve a microcapsule breaking force distribution over the entire surface of the microcapsule paper. If the forces are not evenly distributed, the microcapsule paper will not develop uniformly and the resulting image will have poor tonal characteristics. As an example of a developing means for solving this inconvenience, there is a technique using a point contact developing ball, as disclosed in Japanese Patent Application Laid-Open No. 62-161153.

An image forming apparatus for exposing an image forming light corresponding to image information to such a photosensitive recording medium and developing the same is disclosed in Japanese Patent Application Laid-Open No. 62-231758. An image forming apparatus which selectively leads to a photosensitive recording medium in accordance with
No. 364, an image forming apparatus which scans a plurality of light source lights and guides the light to a photosensitive recording medium;
There is known an image forming apparatus described in Japanese Patent No. 2822 which exposes the same portion a plurality of times via a polygon mirror or the like in a photosensitive recording medium capable of expressing a plurality of colors.

[0007]

By the way, in recent years, the present applicant has invented and applied for an image forming apparatus of a type using a plurality of light emitting elements in order to expose a photosensitive recording medium with image forming light. In this type of image forming apparatus, a plurality of light emitting elements are fixed to an exposure head which is relatively moved along a photosensitive recording medium, and output light from the light emitting elements is blocked by a shielding plate having a pinhole (a through hole). (A mask) to selectively irradiate the photosensitive recording medium.

In this case, the light emitted from the light emitting element is emitted not only from the corresponding pinhole but also as stray light from the non-corresponding pinhole, thereby deteriorating the image quality. was there.

In this type of image forming apparatus, the efficiency of light emitted from a corresponding pinhole (opening) is only about 10% with respect to the total power of light emitted from a certain LED (light emitting element). Most of the remaining light is mixed with each other along the path between the LED, which is another light emitting element, and the corresponding pinhole, and is emitted from the pinhole as unnecessary background light that does not correspond to an image. As a result, image quality deterioration such as deterioration in color reproduction of an image, deterioration in lightness reproduction, and apparent reduction in resolution occurs. In other words, before the output light from one light-emitting element exits from the corresponding pinhole, the output light from another light-emitting element is mixed and unnecessary light exits from the pinhole, and the image quality is formed. Is reduced.

The present invention has been made to solve the above-mentioned various problems, and the output light from a plurality of light emitting elements does not become stray light, thereby improving the image quality of the formed output image. It is an object of the present invention to provide an image forming apparatus capable of performing the above.

[0011]

In order to achieve this object, an image forming apparatus according to the present invention carries a microcapsule containing a photosensitive component and a colorant whose intensity changes with respect to light of a predetermined wavelength. A photosensitive recording medium on which a latent image of image information is formed by exposure, and a plurality of light emitting elements for exposing the photosensitive recording medium, and are relatively moved in a first direction along the photosensitive recording medium. An exposure head for forming an exposure latent image on a photosensitive recording medium, and a feed for generating a relative movement between the photosensitive recording medium and the exposure head in a second direction intersecting the first direction. And an image forming apparatus having a developing means for applying pressure to the exposed photosensitive recording medium to break the microcapsules having low strength, and for developing the latent image with the coloring material flowing out of the broken microcapsules. so Thus, the exposure head includes a substrate for arranging the plurality of light emitting elements thereon, a mask having openings at positions respectively corresponding to the positions of the plurality of light emitting elements, and: And an optical separating means for separating a light propagation space between the substrate and the mask from each other so that the output lights do not cross each other and propagate to the opening.

Since the output light from each light emitting element does not propagate crossing each other due to the optical separation means, unnecessary background light (output light from another light emitting element) is not emitted from the opening.

The image forming apparatus according to a second aspect of the present invention provides
2. The structure according to claim 1, wherein the exposure head further includes a mask holding unit for holding the mask so as to face the substrate, and the mask holding unit is formed integrally with the optical separation unit.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side view showing an embodiment of a photosensitive pressure-sensitive printer 80 as an image forming apparatus, and FIG. 2 is a bottom view of a main part of the photosensitive pressure-sensitive printer 80.

Referring to FIG. 1, the overall structure of a photosensitive pressure-sensitive printer 80 for exposing and developing a microcapsule paper 37, which will be described in detail later, will be described.

A light-shielding cartridge 67 is detachably mounted on an upper part of a case 81 of the photosensitive pressure-sensitive printer 80, and the unexposed microcapsule paper 37 is accommodated in the cartridge 67 in a stacked state. . The lamination state at this time is set so that a light-transmitting support 31 described later of the microcapsule paper 37 faces upward.

The cartridge 67 is a photosensitive pressure-sensitive printer 80
In a state where the microcapsule paper 37 is set at a predetermined position of the case 81, the microcapsule paper 37 is taken out of the cartridge 67 one by one by a half-moon-shaped feed roller 65, and the leading end of the microcapsule paper 37 is exposed by a feed roller 68. It is pulled out toward the table 66 to the right.

The exposure table 66 is supported in a case 81 so as to be able to approach and separate from the exposure head 20 described later, and is urged upward by a spring (biasing means) 63. The exposure table 6
6, a guide portion 661 is formed integrally from the left side to the right side in the figure, and gradually curves and approaches from a position away from the exposure head 20 to a position in contact with the exposure head 20,
The leading end of the microcapsule paper 37 conveyed by the feed roller 68 is guided by the guide portion 661 and enters between the exposure table 66 and the exposure head 20 against the urging force of the spring. Further, a preheater 64a, which is a film-shaped heater, is attached to the surface of the exposure table 66 where the microcapsule paper contacts. The preheater 64a is used to heat the capsule paper to a predetermined temperature in order to improve the sensitivity when exposing the microcapsule paper 37 by the exposure head 20. Therefore, as will be described later in detail, by performing reciprocal scanning of the exposure head 20, a latent image corresponding to the red, green and blue images is formed in a selective range of the microcapsule paper 37.

The unexposed microcapsule paper 37 after leaving the cartridge 67 is kept in an unexposed state by the light-shielding cover of the case 81 or the like. The case cover 82a is configured to be rotatable to a position 82b around an axis d perpendicular to the plane of the drawing for processing when the microcapsule paper is jammed. With the case cover 82a opened, the microcapsule paper jammed in the case can be removed.

The carriage 48 is disposed above the exposure table 66. The carriage has the exposure head 20 on its lower surface, and a developing unit 45 having a pressure roller 46 is provided on the right side of the carriage. Further downstream of the paper path, a film-shaped post heater 64b is disposed on the right side of the developing unit 45, and a discharge roller 75 is disposed further downstream thereof.

The carriage 48 slides on a circular guide shaft 49 fixed in the case so as to extend in a direction perpendicular to the paper surface of the drawing (a direction perpendicular to the transport direction of the microcapsule paper 37). The exposure head 20 is fixed to the exposure table 66 side end surface. A shaft 481 is provided on the left end surface of the carriage 48 on the microcapsule paper feeding side in a direction perpendicular to the guide shaft 49.
Are rotatably supported. On the other hand, a receiving shaft 491 is fixed in the case in parallel with the guide shaft 49, and the receiving roller 482 is placed on the upper surface of the receiving shaft 491 so that the carriage moves along the guide shaft 49. The receiving roller 482 rolls in conjunction therewith.

In FIG. 2, with the carriage 48 retracted to the side of the transport path of the microcapsule paper 37,
The unexposed microcapsule paper 37 coming out from the lower part of the cartridge 67 is guided by a feed roller 68 and
6 is sent to the top. In this case, the surface of the unexposed microcapsule paper 37 is adjusted to 40 to 50 by the preheater 64a.
By heating to about ° C, the sensitivity at the time of subsequent exposure is improved. Then, the exposure operation is performed by the exposure head 20, the pressure development operation is performed through the developing unit 45, the heating operation is performed at about 60 to 80 ° C. after the post heater 64b, and a final color output image is formed. Then, the sheet is discharged out of the photosensitive pressure-sensitive printer 80 by the discharge roller 75.

The pre-heater 64a and the post-heater 64b are configured such that a conductive heating element is patterned on a thin film such as polyimide by printing or the like, and the film itself generates heat by current driving. And
The post-heater 64b heats the microcapsule paper 37 on which the color image has been developed after the development is completed to about 60 to 80 ° C. to completely cure the capsule and close the dye precursor in the capsule, thereby forming a color. This has the effect of fixing.

Next, the photosensitive recording medium will be described in detail with reference to FIG. FIG. 3 shows a cross-sectional structure of a microcapsule paper 37 as a photosensitive recording medium.
On the surface of the component, a component that develops a color upon contact with a co-reactant as a coloring material (a dye precursor, hereinafter sometimes referred to as a chromogen)
And a microcapsule 32 containing a component (photocurable resin) whose mechanical strength changes (photocuring) upon exposure to light of a predetermined wavelength, and a dye precursor (chromogen) in the microcapsule. Reacting co-reactant (color developer)
33 and a mixed coating layer 34 is formed.
4, a sheet-like support 35 is sequentially laminated.

There are three different types of microcapsules in the microcapsules 32. Each microcapsule has a colorless dye precursor for forming one of yellow, magenta and cyan, and a light source of light of three colors. It contains a photocurable resin that is cured by being exposed to light of each wavelength of the primary colors, and a polymerization initiator.

For this reason, for example, blue light (about 470 nm)
Is exposed to the microcapsule paper 37,
Microcapsule 3 containing yellow-only dye precursor
When the photocurable resin 2 is photosensitive-cured and pressure is applied to the microcapsule paper 37, the photosensitive-cured microcapsules (in this case, yellow) are not destroyed, and the uncured microcapsules (in this case, magenta, Cyan) is destroyed, and the magenta and cyan dye precursors flow out of the microcapsules and react with the color developer to form a color, which is mixed to become blue. This blue color is the transparent support 31
Is observed through.

When green light (light having a wavelength of about 525 nm) is exposed on the microcapsule paper 37, the photocurable resin of the microcapsules containing the magenta-only dye precursor is photo-cured, and yellow and yellow are developed by pressure development. The cyan microcapsules 32 are destroyed, and the yellow and cyan dye precursors react with the developer to develop colors, respectively, and become green by color mixing.

Further, when the microcapsule paper 37 is exposed to red light (light having a wavelength of about 650 nm), the photocurable resin of the microcapsules containing the dye precursor of only cyan is photosensitive-cured, and is yellowed by pressure development. , Magenta microcapsules are destroyed, and the yellow and magenta dye precursors react with the color developer to develop colors, respectively, and become red by color mixing.

Further, when all the microcapsules are photosensitive-cured by exposure, they are not destroyed by pressure development, so that color development does not occur, and the surface of the sheet-like support 35 is visually observed via the transparent support 31. You can do it.
The white color of the surface of the sheet-like support 35 becomes a background color,
That is, a color image is formed only in the portion where the color reaction has occurred. Note that this principle of coloring is referred to as self-coloring. Also,
The surface of the light-transmitting support 31 in the microcapsule paper 37 is referred to as a coloring side surface.

In the case of this embodiment, the light transmitting support 3
Examples of the material 1 include resin films such as PET (polyethylene terephthalate) and polyvinyl chloride.

The light-sensitive material made of such microcapsules is greatly affected by humidity, and when stored in a high-humidity condition, the light-transmitting support 31 and the sheet-like support 35 absorb moisture, and the sensitivity is increased. Greatly fluctuates. More specifically, the sensitivity is increased by moisture absorption, but the sensitivity fluctuates about 10 times or more depending on the temperature conditions during high-humidity storage. In an image forming apparatus that exposes the image, this variation causes a great technical problem in order to maintain high image quality.

In order to solve this problem, a moisture-resistant material is selected for the light-transmitting support 31 and the sheet-like support 35, or the moisture-resistant material is further applied to the outer surface or the inner surface (the surface on the capsule side). It is desirable to apply. As an example of such a moisture-resistant material, an optical lens material such as amorphous polyolefin can be widely selected, and a coating material and a method such as deposition of SiO2 or the like can be given.

Further, as another technical problem, when ultraviolet rays are radiated to the microcapsules through the light-transmitting support 31, the capsules change color to yellow, and the chromaticity and density of a white background change. There is a problem that. In order to solve this technical problem, it is desirable to select a material having a low ultraviolet transmittance for the light-transmitting support 31, or to apply a material having a low ultraviolet transmittance to the outer surface or the inner surface.

Examples of the microcapsules 32 include a chromogen of a triphenylmethane-based or spiropyran-based dye, a photocurable resin of an acryloyl group-containing compound such as trimethylolpropane triacrylate, benzophenone,
A photopolymerization initiator such as benzoylalkyl ether,
Known materials such as those encapsulated in polymer walls such as gelatin, polyamide, polyvinyl alcohol and polyisocyanate resin can be used.

The co-reactant 33 may be related to the composition of the chromogen in the microcapsules 32, but may be an acidic substance, for example, an inorganic oxide such as acid clay, kaolin, acidic zinc, or titanium oxide. A known developer such as a phenol novolak resin or an organic acid can be used.

The microcapsules 32 and co-reactant 3
3, a binder, a filler, a viscosity modifier and the like are further added, and the mixture is applied onto the light-transmitting support 31 by an application roller, a spray, a doctor knife, or the like to form a mixed coating layer 34.

As the sheet-like support 35, a transparent, translucent or opaque support, for example, paper (cellulose), synthetic paper, a resin film such as polyester or polycarbonate can be used. The measures against the influence of humidity and ultraviolet rays are as described above.

Next, the configuration of the exposure head 20 of the present invention will be described with reference to FIGS.

FIG. 5 is a schematic sectional view showing only a main part of an exposure head 20 for exposing a microcapsule paper 37 as a photosensitive recording medium, FIG.
FIG. 6 is a top view of the mask holding member 14. FIG. 7 is an explanatory diagram illustrating an arrangement of light emitting elements (LEDs).

The exposure head 20 comprises a plurality of types of light emitting elements 7, 8, 9 and a substrate 1 for supporting (fixing) them.
, Mask 13, mask holding member (mask holding means) 1
4 is provided.

The substrate 1 is manufactured by forming a mortar-shaped concave portion 4 on the surface of a flat substrate 1 made of glass epoxy by cutting or press working, and further forming an electric signal on the surface. The electrode layer 3 of a predetermined land pattern in a plan view for transmitting the light is formed by electroless plating. The electrode layer 3 is made of a copper foil of 35 μm. At the connection point of the bonding wire, nickel 5 .mu.m and gold 0.5 to 1.0 .mu.m are further formed on the copper foil to form a three-layer structure as a bonding pad. In this manner, the required number of concave portions 4 are formed at predetermined positions of the substrate 1, and then the electrode layers 3 formed in a predetermined pattern are formed. It is bonded with a system adhesive.

In the processing of the concave portion, as shown in FIG. 5B, a concave portion 4 having a horn-shaped cross section is formed. in this case,
The bottom surface 4a of each recess 4 is formed parallel to the surface of the substrate 1,
An inclined side surface 4b is formed so as to spread upward from the bottom surface 4a. The electrode layer 3 on the surface of the substrate 1 is also formed in a predetermined pattern along the surface of the recess 4.

The electrode layer 3 on the bottom surface 4a of the recess 4
Red LED7, Green LED respectively with adhesive 6 on the surface
8, blue LED 9 is arranged and fixed. Here, the depths of the recesses 4 are red LED7, green LED8, blue LED9.
Is slightly deeper than the mounting height of
The tops of D7, D8 and D9 are located below the surface of the substrate 1. From the tops of the red LED 7, the green LED 8, and the blue LED 9, an electrical connection is made to a predetermined position of the land pattern electrode layer 3 by a bonding wire 10, and each LED and the bonding wire 10 do not come into contact with air. As described above.

As the adhesive 6, a silver paste is used for the red LED 7, and an epoxy resin or the like is used for the green LED 8 and the blue LED 9. This is because the bottom surface of the red LED 7 is one of the electric terminals, so that it is necessary to make an electric connection with the substrate 1 by the conductive adhesive 6, whereas the green L
In the ED 8 and the blue LED 9, since two electric terminals are disposed on the top surface, an insulating and transparent epoxy resin is used for bonding. By using the transparent adhesive 6,
The output light generated inside the green LED 8 and the blue LED 9 and traveling to the bottom surface passes through the transparent adhesive 6 and passes through the bottom surface 4 of the concave portion 4.
Since the light is reflected at a and is emitted again from the top surface, there is an effect that the output light increases.

The red LED 7 is made of AlGa as its basic material.
As is used, and a DDH structure having a high output and known technology can be applied. The center wavelength of the output light is about 650 nm. There is one electrical terminal on the top and one on the bottom. Green L
The ED 8 and the blue LED 9 both use Ga as their basic material.
Those using N can be applied. The center wavelengths of the output light are about 525 nm and about 470 nm, respectively. There are two of these electrical terminals on the top and not on the bottom.
Each LED emits output light in all directions in the space by applying a current to two electrical terminals in a predetermined direction. A part of the output light emitted in all directions goes directly upward in the drawing, and the other part is reflected by the side surface 4b of the concave portion 4 and similarly emitted upward in the drawing.

The bonding wire 10 is made of a gold wire, and is bonded by heating and ultrasonic bonding to the top surface of each LED and the electrode layer 3 on which the bonding pad is formed.

The sealing material 11 is formed of a thermosetting resin.
Usually, a transparent silicone resin, epoxy resin or the like is used. The thermosetting conditions are usually 150 ° C. for about 4 hours. Since general semiconductor materials such as LEDs have a phenomenon in which when exposed to air, their surfaces are subject to the effects of oxidation, moisture absorption, and the like, and their characteristics are rapidly deteriorated, the sealing material 11 is used for the purpose of avoiding this and the bonding wire 10 and the like. The purpose is to prevent destruction by mechanical shock. In the present embodiment, the mask 13 and the mask holding member 14 are also bonded and fixed by the sealing material 11 for another purpose.

Above the substrate 1, a mask 13 having a plurality of (the same number as the number of light-emitting elements) a plurality of pinholes 12 having a circular through-hole shape is positioned and arranged via a mask holding member 14. . The mask holding member 14 is mounted and fixed in a positioning boss hole 15 on the substrate 1.
A positioning groove 14a for holding a mask is formed on the upper end surface of the mask 4. The mask 13 is loaded in the positioning groove 14a, and the mask 13 is fixed to the substrate 1 by fixing means such as bonding.
And is fixed together. In the present embodiment, the mask 13 and the mask holding member 14 are integrally integrated with the substrate 1 by the sealing material 11.

FIG. 6 is a top view of the mask holding member 14, and the position of the recess is also shown for convenience of explanation. The mask holding member 14 has a separation wall (separation partition) 2 that separates each of the recesses 4 formed on the substrate 1.
4 are integrally formed. This separation wall 2 is shown in FIG.
As shown in (a), the lower end surface contacts the upper surface of the non-recessed region of the substrate 1 (including the upper surface of the electrode layer 3), and the upper end surface of the separation wall 2 contacts the lower end surface of the mask 13. The light propagation space between the substrate 1 and the mask 13 is
Each of the light-emitting elements (LEDs) is separated by the separation wall 2. That is, the light beam emitted from the LED disposed in a certain recess 4 is emitted to the outside of the exposure head only from the pinhole 12 of the mask 13 corresponding to the recess due to the existence of the separation wall 2 surrounding the recess. However, the light is not emitted from the pinholes corresponding to the other concave portions. Since no stray light is generated, a high-resolution image can be formed.

The mask holding member 14 is a single molded product made of a high-precision heat-resistant plastic material. The mask holding member 14 positions the mask 13 in three axial directions through the positioning boss holes 15 on the substrate 1 and further emits each light. Each of the light emitting elements (LE
This is for separating the output light from D) by dividing it into individual spaces by the action of the separation wall 2. As described above, since the thermosetting resin is used for the sealing material 11, when the mask holding material 14 and the mask 13 are simultaneously positioned and adhered and fixed using the thermosetting resin, the mask holding is performed even at the curing temperature of the sealing material 11. It is necessary to use a heat-resistant material so that the member 14 is not deformed. POM or the like can be selected as such a material. The mask holding member 14 provided with the separation wall 2 constitutes the optical separation means of the present invention. In an embodiment, the separation wall may be formed separately from the mask holding member, or may be integrated with the substrate. Also, the separation wall can be integrated with the mask. The shape of the space to be separated is not limited to a square, but various shapes such as a round shape can be adopted.

FIG. 4 is a top view of the mask 13. The mask 13 is formed of stainless steel having a thickness of about 0.1 mm,
The outer shape and the pinhole 12 are processed by etching. In addition, the surface is blackened by a dipping method, which is a non-reflection treatment of light. Also,
In the exposure head 20 of the present invention provided with an optical separation unit,
Since the problem of stray light to an adjacent light source has been solved, there is obtained an effect that there is no particular problem even if such non-reflection processing is not performed.

The pinhole 12 has a hole diameter of φ0.2 mm to φ0.2 mm.
The diameter of the hole determines the resolution of the light pattern supplied to the microcapsule paper 37 as a photosensitive recording medium. In addition, φ0.
The 4 mm sub pinhole 39 is a pinhole for subexposure as described later. These pinholes 12 and 39 are formed facing the tops of the red LED 7, green LED 8 and blue LED 9, respectively. As shown in FIG. 7, in the present embodiment, three LEDs for red are used for image modulation exposure.
One set of 7a, 7b, 7c, 4 LEDs for green
One set includes 8a, 8b, 8c, and 8d, and one set includes four LEDs 9a, 9b, 9c, and 9d for blue. One LED 8d for green and one LE for blue.
D9d is separately provided as an exposure light source for sub-exposure, which is not related to image modulation (the red, green and blue LEDs are turned on and off in accordance with image data to form a desired image). That is, in green and blue, up to a certain energy density level, there is a region where the density of the output image does not change even when light exposure is performed (a region where the photosensitive resin of the microcapsules is not cured). A numerical example was obtained from microcapsule paper in which the density did not change even when the photosensitive material was exposed to 1/5 of the energy density required for the change. By constantly irradiating this 1/5 energy density amount irrespective of the image modulation exposure, the number of LEDs used can be reduced.

The reason why there is no sub-exposure LED in the red LED is that there is no region in which the density of the output image does not change, unlike the microcapsules sensitive to red, such as the blue and green microcapsules. That is, in the red exposure, the area where the density does not change due to the above sub-exposure is about 1/20 or less of the energy density required for the maximum density change.

Since the light source for sub-exposure is prepared only for the light of the necessary wavelength in this manner, the same color density (the hardness of the photosensitive resin is the same for each color) is obtained for each color by one-time light emission. It is. The degree of curing of the photosensitive resin encapsulated in the microcapsules differs in proportion to the received light energy, and when the capsules are pressure-developed, the dye precursor in the capsules flows out in inverse proportion to the degree of curing. This is because the density of the formed image changes in proportion to the exposure energy. That is, since the ratio of the color density of each color becomes equal, the control of the exposure time and the number of times (light energy control) becomes equal for each capsule,
Processing of the image data is simplified. If the color density for one modulation exposure is different for each color, it is necessary to vary the energy for each color in order to form an image of a predetermined hue, and very complicated modulation control must be performed. It is.

The diameter of the pinhole for sub-exposure is φ
Since the hole diameter of the pinhole for image modulation exposure is about φ0.2 mm to φ0.18 mm, the opening area of the pinhole for sub-exposure is smaller than that of the pinhole for image modulation exposure. It is slightly more than four times, and the light energy passing through the aperture is also slightly more than four times.

That is, assuming that the number of LEDs required in a system for exposing without sub-exposure is 12 each for green and blue, the amount of 1/5 of the 12 is reduced to 1 by sub-exposure.
Can be covered by the sub-exposure using the LEDs,
As a result, for both green and blue, 9 LED for image modulation and L for sub-exposure
An exposure head can be constituted by one ED. The opening area is determined so that the light energy for sub-exposure is supplied from one pinhole. By doing so, the number of LEDs to be used can be reduced and the cost can be reduced. .

Since the sub-exposure is irrelevant to the modulation exposure of the image, the aperture diameter of the pinhole can be made large, so that the light use efficiency can be increased, and the above effects can be obtained.

The red, green, and blue LEs for image modulation exposure
D is three LEDs 7a to red for red as shown in FIG.
7c, the reciprocating direction of the exposure head 20 (first
, The X direction in FIGS. 2 and 7), the LED 7a and the LED
The distance X1 between the LED 7b and the distance X1 between the LED 7b and the LED 7c is an integral multiple (for example, 16 times) of one pixel (one dot) of the image formed on the microcapsule paper 37.
While the microcapsule paper 37 is fed in the feed direction (the second direction, the Y direction in FIGS. 2 and 7).
Distance Y1 between D7a and LED 7b, and LED 7b and L
The distance Y1 from the ED 7c is set so as to be shifted by one pixel (one dot) of the image formed on the microcapsule paper 37 or an integer multiple thereof.

Three LEDs 8 for green for image modulation exposure
a, 8b, 8c and three LEDs 9a, 9b for blue,
9c is also arranged as described above. In addition,
The interval Y2 between the set of red LEDs 7 and the set of green LEDs 8 in the second direction (Y direction in FIG. 7) is arranged at a distance of 16 dots, and the set of red LEDs 7 and the blue LED
The interval Y2 with the set of 9 is also spaced by 16 dots.

Here, one set of three green LEDs 8 arranged at intervals of X1 = 16 pixels (16 dots) along the reciprocating movement direction of the carriage 48 (X direction in FIG. 7).
Each of c, 8b, and 8a is displaced by Y1 = 1 pixel (one dot) in the feed direction of the microcapsule paper 37 (Y direction in FIG. 7). Also, along the reciprocating direction of the carriage 48 (X direction in FIG. 7), one set of three red LEDs 7c, 7b, 7a arranged at a distance of X1 = 16 pixels (16 dots) corresponds to the green color. The feeding direction of the microcapsule paper 37 with respect to the set of LEDs (Y in FIG. 7)
Direction), a position advanced by 12 dots, and
The distance between the red LED 7c and the red LED 7b is shifted in the Y direction of FIG. 7 by Y1 = 1 pixel (one dot).
The distance between the ED 7b and the red LED 7a is Y1 in the Y direction in FIG.
= Displaced by one pixel (one dot).

Similarly, one set of three blue LEDs arranged at intervals of X1 = 16 pixels (16 dots) along the reciprocating movement direction (X direction in FIG. 7) of the carriage 48.
9c, 9b and 9a are positions delayed by 12 dots in the feed direction of the microcapsule paper 37 (Y direction in FIG. 7) with respect to the preceding set of green LEDs, and the blue LED 9c and the blue LED 9b Between Y and Y in FIG.
1 = 1 pixel (1 dot) shifted, blue LE
Between D9b and blue LED 9a, Y1 =
They are shifted by one pixel (one dot).

Here, in FIG. 7, Y2 = 10 pixels, and the interval between the blue LED 9a and the red LED 7a is 24 pixels. This is because the number of LEDs of each color is set to an integral multiple (three in the embodiment).

The arrangement relationship of the pinholes 12 formed in the mask 13 is set so as to match the arrangement relationship of the LEDs arranged as described above.

The exposure head 20 having such a configuration is moved at a predetermined speed V, for example, in the + X direction along the horizontal direction (X direction in FIG. 7) while modulating and exposing the corresponding LED according to the image data. , Followed by microcapsule paper 37
Is modulated by one exposure line in the vertical direction (Y direction in FIG. 7) in the figure, and modulated exposure is performed again by moving the exposure head 20 in the −X direction at the predetermined speed, and then the microcapsule paper is again moved by one in the Y direction. Exposure head 20 after feeding by exposure line
Is moved in the + X direction, and the operation of modulating and exposing the LED is repeated to perform exposure of a desired image. By independently modulating and driving each of the LEDs according to the image information while performing the moving scanning in this manner, a light of a predetermined center wavelength is supplied to a predetermined place at a predetermined light power at a predetermined light power, thereby providing a color image. A latent image can be formed. Of course, the sub-exposure LED irradiates light to the entire image forming area of the microcapsule paper regardless of the modulation exposure.

Next, a method for scanning the surface of the photosensitive recording medium using the exposure head 20 of the present invention will be described with reference to FIG.

FIG. 2 is a bottom view of a photosensitive pressure-sensitive printer having an exposure head 20 according to the present invention. For convenience, the microcapsule paper 37 is shown as a perspective view for the sake of explanation of the configuration, and the microcapsule paper 37 is exposed by the exposure head 20 from the back side of the drawing.

As described in detail with reference to FIGS. 2 and 5, the exposure head 20 is formed of a mask (selection / supply means) 13 having a pinhole 12, a mask holding member 14, and the substrate 1. The exposure head 20 is fixed on the carriage 48 described with reference to FIG.
9 so as to be able to reciprocate left and right on the drawing.

On the other hand, a developing device 45 composed of a point contact pressure roller 46 and the like described later is fixed to the carriage 48, and the mounting position of the exposure head 20 is smaller than that of the point contact roller 46 by the microcapsule paper. 37 are set on the upstream side in the feed direction.

As shown in FIGS. 1 and 2, the carriage 48 having the exposure head 20 and the developing unit 45 moves in the direction (X direction in FIG. 2) orthogonal to the feeding direction of the microcapsule paper 37 in a horizontal plane. It is slidably supported by a guide shaft 49 extending along the same, and is mechanically driven by a carriage drive motor 62, a gear 61, and a timing belt 60, and is reciprocated.

FIG. 8 is a graph showing the time change of the moving speed of the carriage 48, and the movement of the carriage will be described with reference to FIG.

The carriage 48 is driven at a maximum speed V (m
/ Sec), scanning cycle T (sec), constant speed time Tc
It is reciprocated in a trapezoidal speed change pattern at (sec).

That is, as shown in FIG.
At a maximum constant scanning speed ± V (m / sec.) In the X direction in FIG. 2 (reciprocating scanning movement).
In FIG. 8, the portion inclined with respect to the time axis (horizontal axis) indicates a stop at the reciprocating movement end and a maximum constant scanning speed ±.
V (m / sec.) Indicates an acceleration range and a deceleration range. Also,
The time Tc is the time required for the carriage 48 to pass the entire distance in the width direction (X direction) of the microcapsule paper 37 (the time required for the maximum constant scanning speed), and is the reciprocating scanning period T.

In each exposure line (one line along the X direction in FIGS. 2 and 7) of the microcapsule paper 37, one set including the plurality of red LEDs 7, one set including the plurality of green LEDs 8, and the plurality of blue LEDs 9 are provided. Are controlled in accordance with image information. In this lighting control, one set of the red LEDs 7c, 7b, 7a, one set of the green LEDs 8c, 8b, 8a, and the blue LEDs 9c, 9
Since there is a set of mounting intervals (pinhole intervals) of b and 9a, the microcapsule paper 37 is fed by the time required for the scanning movement of the carriage 48 and the interval for the exposure of one point in the exposure line. This is performed in consideration of the delay time t according to the time.

That is, when Y1 is equivalent to one dot, focusing on one pixel of the microcapsule paper 37, the one pixel point (exposure point) is white, so that G light, R light and B light are used.
In order to irradiate light, for example, first, the carriage 48
When moving in the forward direction (at the time of moving in the X direction in FIG. 7), the blue L
When the pinhole 12 facing the ED 9c is located at the one pixel point, the blue LED 9c is turned on for a predetermined short time Δt.
Only once, the carriage 48 is temporarily stopped at the end of the outward path. Next, after the microcapsule paper 37 is fed by one dot in the Y direction in FIG. 7, when the carriage 48 moves in the backward direction (at the X ′ direction in FIG. 7), it faces the blue LED 9b. When the pinhole 12 is located at the one pixel point, the blue LED 9b is turned on once for a predetermined short time Δt, and the carriage 48 is temporarily stopped at the end of the return path. Further, after the microcapsule paper 37 is fed by one dot in the Y direction in FIG. 7, the carriage 48 moves in the forward direction (X in FIG. 7).
Pinhole 1 facing the blue LED 9a)
2 is located at the one pixel point, the blue LED 9
After a is lit once for a predetermined short time Δt, the carriage 48 is temporarily stopped at the end of the outward path. In this way, as shown in FIG. 9, the blue LED 9c is applied to one pixel point of interest every half the scanning period T.
The lights are turned on at short intervals Δt in the order of → 9b → 9a.

Next, after the microcapsule paper 37 is fed by 12 dots in the Y direction in FIG. 7, the carriage 48 is moved in the backward direction (X ′ in FIG. 7).
Pinhole 1 facing green LED 8c)
2 is located at the one pixel point of interest, the green L
After turning on the ED 8c once for a predetermined short time Δt, the carriage 48 is temporarily stopped at the end of the return path. Then, after the microcapsule paper 37 is fed by one dot in the Y direction in FIG. 7, when the carriage 48 moves in the forward direction (at the time of movement in the X direction in FIG. 7), the pinhole facing the green LED 8b is moved. When 12 is located at the one pixel point, the green LED 8b is turned on once for a predetermined short time Δt, and then the carriage 48 is temporarily stopped at the end of the outward path. Further, after the microcapsule paper 37 is fed by one dot in the Y direction in FIG.
When moving in the backward direction (at the time of moving in the X direction in FIG. 7), the green L
When the pinhole 12 facing the ED 8a is located at the one pixel point, the green LED 8a is turned on for a predetermined short time Δt.
Only once, the carriage 48 is stopped once at the end of the return path.

Next, the microcapsule paper 37 is fed by one dot in the Y direction in FIG.
As for D, the lighting is repeated every predetermined short time Δt while reciprocating the carriage 48 in the order of the red LEDs 7c → 7b → 7a.

At the time of this scanning exposure, in addition to the above-described image modulation exposure, an auxiliary exposure by the blue LED 9d and the green LED 8d is always performed. The light energy of the auxiliary exposure is set to the maximum light energy that does not cure the capsule as described above.

Therefore, each of the blue LEDs 9a to 9c and the green LED
8a to 8c and the light energy of each color emitted from the red LEDs 9a to 9c are the same, but the blue wavelength light and the green wavelength light are sub-exposed from the blue LED 9d and the green LED 8d via the pinhole 39, respectively. Because the added light energy is added, the microcapsules of each color are cured by the same ratio. In this case, the degree of cure of the capsules of each color is maximized, and all the capsules are not destroyed even when subjected to pressure development, so that no coloring reaction occurs. That is, the color (white) of the surface of the sheet-like support 35 via the light-transmitting support 31 remains visible.

Of course, blue LED 9a for image modulation exposure
-9c, green LEDs 8a-8c, and red LEDs 9a-9c are changed according to the image data to form an exposure latent image (capsule curing degree change pattern image) corresponding to the image data.
It is formed in.

As shown in FIG. 9, the reason for irradiating the same exposure position (one pixel point) on the microcapsule paper 37 a plurality of times with a time interval is as follows.

That is, as illustrated in FIG. 10, the vertical axis represents the cyan optical density, and the horizontal axis represents the total amount of exposure energy density (J / m 2). In FIG. 10, a solid line A shows a change in cyan color optical density when the red LED is irradiated only once, and a dotted line B divides the red LED into three times at a time interval of half the scanning period T. 4 shows the change in the optical color density of cyan when irradiated with light.

In FIG. 10, the color optical density of cyan is
In order to obtain a 10% density, that is, D10 = 0.42, it is necessary to give an exposure energy density of 3.3 (J / m2) in one light irradiation. It suffices to provide an exposure energy density of 2.2 (J / m2) in total.

As can be understood from the comparison of FIG.
When the exposure energy density (J / m 2) is in the range of 0.5 to 3.3, the same cyan optical color density is required to be expressed.
It can be seen that a small exposure energy density is required when the light irradiation is divided into three times, but a large exposure energy density is required when the light irradiation is performed once.

The polymerization reaction rate between the polymerization initiator of the microcapsules 32 and the photocurable resin in the microcapsule paper 37 due to the light irradiation is not so high, and is more appropriate than applying a large amount of exposure energy at once. This is because the above-described polymerization reaction is more easily promoted when the exposure energy is input little by little in a plurality of times (for example, 2 to 6 times) at time intervals.

That is, even if the output of the LED, which is one light emitting element, is reduced or the number of the LEDs is small, a sufficient color optical density can be obtained.

The microcapsule paper 37 is preferably exposed and developed at a constant speed over the entire surface.
Therefore, the moving distance L (m) at a constant speed corresponding to the minimum speed constant time Tc required for exposing and developing the microcapsule paper 37 is at least all the pinholes 1.
2 must be greater than or equal to the range that passes. The constant speed moving distance L (m) depends on the width of the microcapsule paper 37, the arrangement pattern of the pinholes 12, and the maximum speed V (m / se).
c.) can be freely designed.
If numerical examples are given, L = 0.1118 (m), V = 0.86 (m / sec.)
It is. Thus, the entire surface of the microcapsule paper 37 of A6 size can be exposed and developed.

Next, the electrical configuration will be described. FIG. 11 shows an electrical configuration of a control circuit (control means) of the photosensitive pressure-sensitive printer 80. The control circuit is CPU 70, ROM 7
The CPU 70 is connected to a connector 74 for inputting RGB image data from an external host computer via an I / O port 73, and is connected to the CPU 70 via the I / O port 73. A drive circuit 77 for the drive motor 78 of the feed roller 68 and a drive circuit 76 for the carriage feed servomotor 62 are connected.

The ROM 71 has a program for controlling the operation of the entire apparatus, a program for calculating and determining the lighting time and timing of each color LED of the exposure head 20 from input image data, and a program for determining the order of BGR exposure. To control the driving of the feed roller 68 and the discharge roller 75,
Various programs such as a program for transporting the microcapsule paper 37, a program for controlling the carriage driving motor 62 for carriage feed in accordance with the sequence of the BGR exposure, and a program for reciprocally scanning the carriage are stored. Operates according to these programs. The RAM 72 is a buffer in which external input data is temporarily stored. In the photosensitive pressure-sensitive printer 80,
When the RGB data of the output image is sent, the image data is sequentially stored in the buffer of the RAM 72.

Each LED of the exposure head 20 is connected to a flexible harness 487 by a driving circuit (not shown).
(See FIG. 2), and is electrically driven and controlled to be turned on and off according to image information.

Next, the developing process of the microcapsule paper will be described with reference to FIGS. FIG.
Is an embodiment of the developing device 45 for developing the microcapsule paper 37. Note that the exposed microcapsule paper 37 is not shown for simplicity.

The developing device 45 as a pressure developing means realizes a developing process by elastically pressing the surface of the microcapsule paper 37 by point contact, and presses the point contact roller 46 against the microcapsule paper 37 while pressing it. By changing the position, only the development area is pressure-developed. In order to change the pressing position, the microcapsule paper 37 is moved in the moving direction of the point contact roller 46 while the point contact roller 46 is reciprocated along one axis in parallel with the microcapsule paper 37 to reduce the size of the apparatus. It is good to move in the direction orthogonal to.

At the point of pressurization by the point contact roller 46, the microcapsules are pressure-developed and destroyed by a small pressing force, and their inclusions (colorless dye precursor) flow out to cause a color development reaction with the color developer. Occur. And the point contact roller 46
The color image is visualized in the development area by the relative movement of the microcapsule paper 37 and the microcapsule paper 37.

In the embodiment shown in FIG. 12, the microcapsule paper 37 to be pressure-developed is supplied on a substantially flat base 47. The base 47 can be formed into a roller shape in addition to a flat surface and can be used for feeding the microcapsule paper 37.

At least one point contact roller 46 is arranged so as to elastically press-fit with the microcapsule paper 37, and the point contact reciprocates within a predetermined range of the base 47 corresponding to the microcapsule paper 37. A carriage 48 is supported so as to be able to reciprocate along a guide shaft 49 which is parallel to the surface of the base 47 and orthogonal to the feeding direction of the microcapsule paper. An arm support shaft 481 is provided on a side surface of the carriage 48 on the side of discharging the microcapsule paper.
The arm 483 is supported by an arm support shaft 481 so that one end of the arm 483 is rotatably supported on the arm support shaft 481 in a plane parallel to the upper end surface of the arm.

At the other end of the arm 483, a bearing support shaft 482 extending in parallel with the arm support shaft 481 is protruded, and the bearing support shaft 482 is provided with an inner ring of a bearing 51 such as a ball bearing. I have.

The point contact pressure roller 46 is formed in a ring shape, and has a circular cross-section perpendicular to the rotation center axis, and has the largest cross-sectional diameter at the center and gradually decreases as the distance from the center increases. Is formed. That is, the outer peripheral surface of the roller is a curved surface whose center is convex. The inner peripheral surface of the point contact pressure roller 46 is press-fitted and fixed to the outer peripheral surface of the bearing 51. Therefore, the point contact pressure roller 46 is
The microcapsule paper 37 is rotatable around an axis parallel to the feeding direction.

On the other hand, a step portion 484 is formed on the carriage 48 so as to protrude above the arm 483, and the step portion 484 is vertically moved along a direction perpendicular to the upper end surface of the base 47. Adjustable screw 485 for adjustable movement
, And a compression spring 486 is interposed between the tip of the adjusting screw 485 and the upper end surface of the arm 483. Therefore, the point contact pressure roller 46 is urged toward the upper end surface of the base 47 by the urging force of the compression spring 486. Further, the urging force of the compression spring 486 is
1 is urged in the counterclockwise direction in FIG. 1, but its rotation is regulated by the contact of the receiving roller 482 with the receiving shaft 491. The biasing force (pressing load) of the compression spring 486 can be arbitrarily adjusted by rotating the adjusting screw 485 to move forward and backward.

Here, the urging force of the point contact roller 46 on the microcapsule paper 37 can be replaced by various devices such as a pneumatic device, a hydraulic device, or a solenoid instead of using the pressing spring 486. It is also possible to use not only an elastic body but also an electromagnetic force. In short, any biasing means between the point contact roller and the base side (microcapsule paper side) may be used.

A timing belt 60 is fixed to the carriage 48.
0 is reciprocated by the carriage drive motor 62. The carriage 48 reciprocates in parallel with the base 47 by the forward / reverse movement of the timing belt 60, and the pressure point of the point contact roller 46 is sequentially changed by the reciprocal movement.

The carriage drive motor 62 is capable of controlling the direction and amount of rotation, and may employ an open-loop control pulse motor. Also,
In addition to the pulse motor, a general DC / AC motor or the like can be used.

When the carriage 48 is moved along the guide shaft 49 and the pressure development of one line is completed, the feed roller 68 is rotated by one line or an integral multiple of one line to convey the microcapsule paper 37 by a fixed amount. By repeating the operation of moving the carriage 48 and performing one line of pressure development, pressure development is performed over the entire development area.

Next, the operation of the present embodiment will be described with reference to FIGS.
This will be described with reference to the flowchart of FIG.

First, when the user mounts the cassette 67 on the printer body and turns on the power switch, the heater 64 is turned on.
a, 64b are energized to a predetermined temperature.

Thereafter, image data of an image to be output and a print start command signal are input from a host computer connected to the printer. The image data is supplied as data in a two-dimensional bitmap format.
Information indicating the density for each GB component is also included in the image data. The input image data is stored in the RAM.

In response to the print start command signal, the CPU 70 rotates the half-moon roller 65 and the feed roller 68 to feed out one microcapsule paper 37 from the cassette 67 and move it onto the exposure table 66 (S2). At this time, the leading end of the sheet is located on the movement locus of the blue LED 9d on the exposure head 20.

Thereafter, the row counter j is initialized (S
4) A process for setting exposure data (drive data) for one exposure line for each LED is performed (S6). This processing is performed as shown in the flowchart of FIG. First, based on the density information of each color component of each pixel of the input image data, each pixel is exposed once or a plurality of times (in the case of this embodiment, at most three times). Calculate driving data. In other words, the LED driving time and light emission intensity are set for each exposure so that one pixel is exposed three times at the maximum. That is,
Since the total amount of exposure energy is associated with the image density to be obtained and stored in the table in the ROM 71, the total amount of exposure energy for each color is obtained based on the density information for each color of the target pixel. The value obtained by dividing the obtained total amount of exposure energy into three equals is the exposure energy per exposure. However, if the value is less than the predetermined reference value, the number of exposures is set to two or less, and the exposure energy for each exposure is calculated.

According to the obtained exposure energy value, L
The drive time and the emission intensity of the ED are stored as a table in the ROM 71, and the LED drive is performed each time when each color component of the target pixel is exposed once or plural times (up to three times) with reference to the table. RAM 7 is required for data
2 are sequentially stored. In short, LED driving data for three exposures is calculated from the input image data.

After this operation, the first drive data of each pixel on the j-th row of the image indicated by the image data by the B light is set (stored) in the line memory as drive data for the blue LED 9c (S61). Next, the driving data of the second exposure of each pixel in the (j-1) th row with the B light is indicated by the blue LED 9.
b is set in the line memory as drive data for b (S6
2) Third drive data of each pixel on the j-2th row exposed to the B light is set in the line memory as drive data for the blue LED 9a (S63).

Thereafter, the first drive data of each pixel on the j-th U-th row exposed by the G light is set in the line memory as drive data for the green LED 8c (S64). Here, the constant U is a value of 12 in this embodiment. This is because the distance between the blue LED 9c and the green LED 8c is 12 exposure lines (dots), and the exposure timing is delayed accordingly. Next, the driving data of the second exposure by the G light of each pixel in the (jU-1) th row is indicated by a green LED.
8b is set in the line memory as drive data for 8b (S
65), the third drive data of each pixel on the j-U-2th row exposed by the G light is set in the line memory as drive data for the green LED 8a (S66).

Further, the first driving data of each pixel on the j-th row by exposure to the R light is set in the line memory as driving data for the red LED 7c (S67). Here, the constant V is 24 in the case of this embodiment. This is because the distance between the blue LED 9c and the red LED 7c is 24 exposure lines (dots), and the exposure timing is delayed accordingly.

Further, the drive data of the second exposure by the R light of each pixel on the (jV-1) -th row is set in the line memory as drive data for the red LED 7b (S68), and the j-th drive is performed.
The drive data of the third exposure of each pixel on the -V-2th row with R light is set as drive data for the red LED 7a in the line memory (S69), and the process exits from this processing routine.

Thereafter, the CPU 70 moves the carriage 48 from the stop position outside the image forming area of the microcapsule paper 37 in the X direction, and the processing routine (S6).
Each LED is driven based on the drive data set by (1). At this time, data is sequentially read from the drive data of the LED corresponding to the pixel at one end of each exposure line toward the pixel at the other end, and the LED is driven. The moving position of the carriage 48 in the X direction is grasped by the driving amount of the carriage feed motor 62, and the corresponding drive data for exposing the pixel at the position where the pinhole 12 of the exposure head is located is sequentially read. Also, as shown in FIG. 7, the position of the LED is shifted by 16 dots for each exposure line, so that a delay of 16 dots and a delay of 32 dots occurs in the second exposure and the third exposure, respectively. Exists. At this time,
In the present embodiment, since the output light from each LED is separated from each other by the separation wall 2, unnecessary color light is not mixed in the light emitted from the pinhole 12, and based on the image data. Thus, an exposure latent image can be formed faithfully.

While the carriage 48 is moved to perform the exposure, the blue LED 9d and the green LED 8d are constantly turned on, and the sub-exposure using the B light and the G light is performed.

In this way, when the exposure for one line is completed and the carriage 48 stops on the side opposite to the movement start side,
The CPU 70 rotates the feed roller 68 to convey the microcapsule paper 37 by one line, and increments the row counter j (S10).

Thereafter, the CPU 70 determines whether or not the exposure has been completed (S12), and if not completed (S1).
2; YES), returning to the processing step S6 to perform the next exposure processing. For example, if the first exposure for the pixels in the first row was performed immediately before by the blue LED 9c, the first exposure for the pixels in the second row was performed by the blue LED 9c, For the pixel, the second exposure is performed by the blue LED 9b. This is followed by the third
The first exposure is performed by the blue LED 9c for the pixels in the row, and the second exposure is performed in blue L for the pixels in the second row.
This is performed by the ED 9b, and the last third exposure is performed by the blue LED 9a for the pixels in the first row. As described above, when the microcapsule paper is successively sent and is exposed by the LED for image modulation and the LED for sub-exposure, the microcapsule paper 37 is held between the point contact pressure roller 46 and the base 47. That is, pressure development of the exposed capsule is also performed at the same time.

In this manner, the exposure and the pressure development are performed simultaneously, and when the exposure is completed, step S12 becomes NO, and the CPU 70 performs the pressure development over all the latent image forming areas where the pressure development has not been performed. It repeats (S14). That is, the operation of moving the carriage 48 with the LED turned off and feeding the microcapsule paper for one line is repeated a predetermined number of times. Thereafter, the carriage 48 is retracted to the side of the capsule paper path (S16), and the discharge roller 75 is driven to discharge the developed microcapsule paper out of the apparatus. In this way, a full-color image with good image quality is formed, and the microcapsule paper itself can be preserved. The developed microcapsule paper has 2 visible images.
Since it is held between two sheets (one of which is transparent), it does not break during handling, has good environmental resistance, can be stored for a long time, and has a good appearance.

As described in detail above, the photosensitive pressure-sensitive printer 80 as the image forming apparatus of the present invention is not limited to the above-described embodiment, but can be variously modified.

The photosensitive recording medium of the present invention is not limited to the above-mentioned microcapsule paper but can be variously modified. As the microcapsule paper, in addition to the above-mentioned self-coloring type, a transfer type can also be used. A transparent base sheet carrying microcapsules and a developing material surface of an image receiving paper carrying a developing material are superimposed on a microcapsule surface of the base sheet so as to be integrated in a releasable manner. May be fed from a cartridge with the exposure head side, exposed and developed as a unit, discharged outside the apparatus, and then the image receiving paper may be peeled off. The dye precursor as a color material that has flowed out of the microcapsules that have been broken by pressure is transferred to a developer on the image receiving paper, and reacts with the developer to develop a color and become visible.

In place of the dye precursor, a pre-colored pigment or dye may be encapsulated in the microcapsule together with the photosensitive material. In this case, transfer-type image formation is possible by integrating the image receiving paper (plain paper) without a developer into the base sheet in a releasable manner. This is because the peeling causes the image to appear on the image receiving paper.

Further, in addition to microcapsule paper, an image forming apparatus using a photosensitive recording medium such as a silver halide film, a diazo type photosensitive paper or the like, which is exposed to light by exposure and developed by being exposed to light. Then, since there is a problem relating to the present invention, an equivalent effect can be obtained by using the solution of the present invention.

The point contact roller 46 is used as pressure developing means.
In addition, it is also possible to employ a point contact ball or a pressure roller in line contact. In addition, all of the embodiments in which the microcapsules can be broken under pressure can be adopted.

Further, the light emitting element is not limited to the LED only, and various structures such as an EL light emitting element, a plasma light emitting element, a laser light emitting element and the like can be applied.

The light emitting element does not need to be composed of red, blue and green, and various wavelengths can be selected according to the sensitivity characteristics of the photosensitive recording medium. For example, infrared light,
Red or green may be selected, or far infrared light, near infrared light, or red may be selected. Ultraviolet rays and far ultraviolet rays are also effective examples of color choices of the light emitting element.

Further, the number of colors of the light emitting elements is not limited to three colors of red, green and blue, but may be one or two colors, or an ordinary color printer using yellow, magenta, cyan and black as a color former. And four or more colors can be selected.

[0125]

As is clear from the above description,
An image forming apparatus according to claim 1, which carries a microcapsule containing a photosensitive component and a colorant whose intensity changes with respect to light of a predetermined wavelength, and a photosensitive recording medium on which a latent image of image information is formed by exposure. An exposure head having a plurality of light emitting elements for exposing the photosensitive recording medium, the exposure head being relatively moved in a first direction along the photosensitive recording medium, and forming an exposure latent image on the photosensitive recording medium; Feed means for generating a relative movement between a photosensitive recording medium and the exposure head in a second direction intersecting the first direction; and a micro-pressurizing the exposed photosensitive recording medium by pressing the exposed photosensitive recording medium. A developing unit for breaking the capsule and causing the latent image to become visible with the coloring material flowing out of the broken microcapsule, wherein the exposure head further comprises: To A substrate for placing, and a mask having openings at positions corresponding to the positions of the plurality of light emitting elements, respectively, so that output lights from the respective light emitting elements do not cross each other and propagate to the openings. Optical separating means for separating the light propagation space between the substrate and the mask from each other.

With this configuration, the output light from each of the plurality of light emitting elements disposed on the substrate of the exposure head is
By the optical separation means, the light propagation space between the substrate and the mask is separated from each other so that the output lights from the respective light emitting elements do not cross each other and propagate to the opening, so that they are mixed with each other. Unnecessary background light that does not correspond to the image is not emitted from the entire mask hole, so that stray light does not cause color reproduction, brightness reproduction, reduction in resolution, etc. of the image, and the image quality of the formed output image It has a remarkable effect that it can be improved.

The image forming apparatus according to claim 2 is
2. The structure according to claim 1, wherein the exposure head further includes a mask holding unit for holding the mask so as to face the substrate, and the mask holding unit is formed integrally with the optical separation unit.

Since the light emitting element and the mask having an opening corresponding to the light emitting element are not only positioned and held, but also serve as an optical separating means, a simple structure can suppress stray light and provide a sufficient image. The effect that quality is obtained is produced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a photosensitive pressure-sensitive printer for processing microcapsule paper.

FIG. 2 is a bottom view of a main part of the photosensitive pressure-sensitive printer.

FIG. 3 is a schematic sectional view of a microcapsule paper.

FIG. 4 is a top view of the mask.

FIG. 5A is a schematic cross-sectional view of an exposure head, and FIG.
FIG. 4 is an enlarged sectional view of a main part of a concave portion.

FIG. 6 is a top view of the mask holding member.

FIG. 7 is an explanatory diagram illustrating an arrangement of LEDs.

FIG. 8 is a graph showing a moving speed of a carriage.

FIG. 9 is a diagram showing a timing chart of multiple exposures for one pixel.

FIG. 10 is a graph illustrating the effect of multiple exposures.

FIG. 11 is a block diagram illustrating an electrical configuration of the photosensitive pressure-sensitive printer.

FIG. 12 is a configuration diagram of a developing device that performs pressure development on microcapsule paper.

FIG. 13 is a flowchart showing a main operation of the CPU.

FIG. 14 is a flowchart showing a process of setting exposure data for one line among main operations of the CPU.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Separation wall as an optical separation means 4 Depression 7, 8, 9 LED as a plurality of light emitting elements 12 Pinhole as an opening 13 Mask 14 Mask holding member 20 Exposure head 32 Microcapsule 33 Developing material 37 Exposure recording Microcapsule paper as a medium 45 Developing device 46 Point contact pressure roller 80 Image forming apparatus

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G03F 7/004 514 7/26 521

Claims (2)

[Claims] 1. A microcapsule containing a photosensitive material and a colorant, the intensity of which changes when exposed to light of a predetermined wavelength, is carried.
A photosensitive recording medium on which a latent image of image information is formed by exposure; and a plurality of light-emitting elements for exposing the photosensitive recording medium. The photosensitive recording medium is relatively moved in a first direction along the photosensitive recording medium. An exposure head for forming an exposure latent image on a recording medium; a feeding means for generating a relative movement between a photosensitive recording medium and the exposure head in a second direction intersecting the first direction; An image forming apparatus, comprising: developing means for applying pressure to the exposed photosensitive recording medium to break the microcapsules having low strength, and to make the latent image visible by the coloring material flowing out of the broken microcapsules. Wherein the exposure head comprises: a substrate for arranging the plurality of light emitting elements thereon; a mask having openings at positions respectively corresponding to the positions of the plurality of light emitting elements; An image forming apparatus comprising: an optical separating unit that separates a light propagation space between the substrate and the mask from each other so that output lights from the elements do not cross each other and propagate to the opening. 2. The apparatus according to claim 1, wherein the exposure head further comprises a mask holding means for holding the mask so as to face the substrate, wherein the mask holding means is formed integrally with the optical separating means. The image forming apparatus according to claim 1.