JPH0527332A - Image forming device - Google Patents

Abstract

PURPOSE:To inexpensively provide a high-resolution and high-tone image forming device. CONSTITUTION:A first latent image is formed on a reversible thermosensible recording medium 70 by a thermal head 73 based on inputted RGB data. At this time, the temperature of the head 73 can be controlled every picture element and it is changed by controlling the energizing quantity of the head 73 according to inputted RGB signals. Besides, the latent image is formed on a microcapsule paper 12 by passing the medium 70 and the paper 12 under a light source at an identical speed by making them adjacent and irradiating them with light from the direction of the medium 70. That means, the medium 70 on which the first latent image is formed is used as a light control means for forming the second latent image on the paper 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly to a copying machine or a printer apparatus using a photosensitive recording medium.

[0002]

2. Description of the Related Art FIG. 7 shows an analog exposure method as a specific example of a conventional exposure method. FIG. 7 is a schematic configuration diagram of a light and pressure sensitive copying machine, in which a light and pressure sensitive paper 12 (hereinafter referred to as microcapsule paper) and a color developing paper 28 (hereinafter referred to as recording paper) are used. Microcapsules are coated on the surface of the support of the microcapsule paper 12, and the microcapsules contain a dye precursor that reacts with a developer, which will be described later. Previous term recording paper 28
The surface of the support is coated with a color developer, and color is developed by reacting with the dye precursor. For details, see US Pat.
It is described in the specification of No. 99209, etc. and is omitted here.

Hereinafter, only the exposed portion of the copying machine 1 will be briefly described. Below the platen glass 2 in the upper part of the copying machine 1, a light source unit 5 including a halogen lamp 5a, a reflector 5b, a reflecting mirror 8 and the like reciprocates along an axis 13 installed in parallel with the platen glass 2. It is arranged as possible. The light source unit 5 irradiates the platen glass 2 with linear light in a direction orthogonal to the moving direction. The emitted light passes through the transparent platen glass 2 and is reflected downward by the document 4 placed on it.

Below the original table glass 2, a mirror section 9 provided with reflecting mirrors 9a and 9b so as to be movable separately from the light source section 5 is arranged, and the light reflected from the original 4 is reflected by the reflecting mirror. The light is reflected in the order of 8, 9a and 9b and guided so as to be parallel to the moving direction of the light source unit 5.

A projection lens 7, which is normally fixed, and a filter 6 for adjusting the color tone of a copied image are arranged below the original platen glass 2, and the light reflected by the reflection mirror 9b is projected. It is incident on the lens 7. The lens 7
The light projected by is reflected by the reflection mirror groups 10a and 10b.

An exposure table 11 for exposing the microcapsule paper 12 is arranged to the right of the reflection mirror 10b, and a reflection mirror 10c for switching an optical path is provided between the reflection mirror 10b and the exposure table 11. It is arranged. Therefore, while the light source unit 5 moves along the axis 13,
By moving the microcapsule paper 12, the image information on the original 4 is sequentially formed on the microcapsule paper 12.

In this way, the light is projected directly onto the copy original,
By forming an image directly on the photoreceptor with the reflected light, it is possible to obtain an image with high gradation and high resolution.

As a conventional digital image forming apparatus using the above-described low-sensitivity photoconductor, a digital static exposure system using a liquid crystal shutter has been proposed. FIG. 8 is a schematic configuration diagram of a full-color printer using the above-mentioned microcapsule paper. In FIG. 8, the printer 100 is provided with a liquid crystal exposure device 102, and is configured such that an elongated microcapsule paper 12 as a photosensitive recording medium is conveyed in an exposure area 115 below the liquid crystal exposure device 102.

The liquid crystal exposure apparatus serves as a halogen lamp 53 as a light source, a reflector 53a for reflecting the light emitted from the halogen lamp, and a condensing means for collimating the light emitted from the halogen lamp 53 and the reflected light from the reflector 53a. Condenser lens 53b, infrared cut filter 54 for cutting infrared rays, condenser lens 53b
And a reflection mirror 8 as an optical path changing means for changing the optical path of light passing through the infrared cut filter 54, and a filter 6R for decomposing the reflected light reflected by this reflection mirror into any one of red, green and blue. , 6G, 6B, and LCD shutter 37.

The light from the halogen lamp 53 becomes parallel light by the condenser lens 53b, and the infrared cut filter 5
After passing through 4, the light enters the reflection mirror 8. Filter 6R,
6G and 6B are driven by a filter driving device (not shown), and a filter of a color corresponding to an image signal for controlling the LCD shutter 37 is inserted in the optical path. Then, the parallel light that has passed through the condenser lens 53b enters the reflection mirror 8 and is reflected, and the reflected light is filtered by the filters 6R and 6R.
G, 6B decomposed into red, green or blue single color, L
The liquid crystal pixels of the CD shutter 37 are transmitted and the microcapsule paper 12 is irradiated with the light. The LCD shutter 37 is opened / closed as needed for each color filter and each pixel in response to an image signal to form a full-color image on the microcapsule paper 12. In other words, on the microcapsule paper 12, red, green,
By overlapping and exposing three times with blue, a latent image having a size of the LCD shutter and a resolution based on the number of pixels of the LCD shutter is formed.

[0011]

However, when the conventional analog exposure method is used, variations in the sensitivity characteristics of the photosensitive recording medium appear in the output image as they are, so that only an output image with poor color reproducibility can be obtained. There was a problem. Even if it is possible to shift the color of the entire output image to a color close to a visually pleasing color even if correction is performed with a color filter, etc., a fundamental solution for improving the color reproducibility of the output image is not reached. Not in.

Further, in the analog exposure system, there is a problem that it can be used as a copying machine but cannot be used as a digital output device such as a printer.

When static exposure is performed on a photosensitive recording medium using a liquid crystal shutter as in the second conventional technique, it is possible to enhance the color reproducibility of an output image by digital color correction processing. However, due to the static exposure, there is a problem that the size of the liquid crystal and the fineness of the cells of the liquid crystal are reflected as they are in the output image, making it difficult to increase the resolution and increase the size of the output paper. Furthermore, it is difficult to manufacture high-definition products with large-sized liquid crystal shutters, which increases the cost of the shutter, and when using large-sized liquid crystal shutters, the size of the entire device must be increased. there were.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a digital image forming apparatus having high resolution and high gradation at low cost.

[0015]

To achieve this object, an image forming apparatus of the present invention comprises a light source for irradiating a moving photosensitive recording medium with light necessary for exposing the photosensitive recording medium, and each pixel. The reversible thermosensitive recording medium and the photosensitive recording medium are brought into close contact with each other and moved at the same speed, and the reversible thermosensitive recording medium is moved by the thermal control means to adjust the density gradation according to the density gradation. Means for forming one latent image,
The photosensitive recording medium and the reversible thermosensitive recording medium are brought into close contact with each other, light is emitted from the light source, and means for forming a second latent image on the photosensitive recording medium by the transmitted light of the first latent image is provided.

[0016]

In the invention having the above structure, the first latent image is recorded on the reversible thermosensitive recording medium by using the thermal recording source whose temperature can be controlled for each pixel, and the reversible thermosensitive recording medium and the photosensitive recording medium are recorded. Close to each other and irradiate light from the reversible thermosensitive recording medium side,
A second latent image is formed on the photosensitive recording medium by using the reversible thermosensitive recording medium as the light control medium.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

First, the structure of the reversible thermosensitive recording medium 70 will be described with reference to FIG. FIG. 2 is a sectional view of the thermoreversible display sheet, in which the recording layer 3 is provided on the transparent polyester film 2, and the overcoat layer 4 is provided to protect the recording layer 3. The recording layer 3 is in a state where an organic low molecular weight substance is dispersed in the resin.

Next, the cloudy state and transparent state of the reversible thermosensitive recording medium 70 will be described with reference to FIG. In the state on the left side of FIG. 3, since the particles of the organic low-molecular-weight substance in the reversible thermosensitive recording medium 70 are composed of a relatively large single crystal, light incident on the reversible thermosensitive recording medium 70 passes through the crystal interface. It passes few times, transmits without being scattered, and appears to be transparent as a whole. In the state on the right side of FIG. 3, since the particles of the organic low molecular weight substance in the reversible thermosensitive recording medium 70 are composed of polycrystals, the light entering the reversible thermosensitive recording medium 70 is repeatedly incident at the crystal interface. Refracted and scattered, and appears cloudy as a whole.

The thermoreversible characteristics of the reversible thermosensitive recording medium 70 will be described with reference to FIG. First, when the reversible thermosensitive recording medium 70 is in a cloudy state at room temperature, when it is heated, the transmittance starts to increase from temperature 1 and reaches the maximum transparent state at temperature 2. And even if it is cooled to room temperature, the transparent state is maintained. This is because the organic low-molecular-weight substance changes from a cloudy polycrystal to a semi-molten state in the process of heating from temperature 1 to temperature 2, and the crystal grows to a transparent single crystal when cooled to room temperature again. Is. Next, when the reversible thermosensitive recording medium 70 in the transparent state is reheated to a temperature of 3 or more, it becomes an intermediate state between the maximum transparent state and the maximum cloudy state. When it is cooled to room temperature, it returns to the original cloudy state. This is because the organic low molecular weight substance melts at a temperature of 3 or higher, and polycrystals are precipitated in the process of cooling to room temperature.

When the temperature is further increased from the temperature 1 to the temperature 2 and cooled to room temperature, the intermediate state between the maximum transparent state and the maximum cloudy state is maintained (temperature 4). The temperature 1 is about 50
The temperature 2 is 56 to 68 degrees, and the temperature 3 is about 72 degrees.

The image forming means for recording on the reversible thermosensitive recording medium 70 is the thermal head 16, and the transparent state and the cloudy state are set for each pixel by changing the energy applied to one pixel determined by the resolution of the thermal head. can do. Further, by providing the reversible thermosensitive recording medium 70 with an intermediate temperature between the temperature 1 and the temperature 2, the transmittance can be freely adjusted. Details of the reversible thermosensitive recording medium 70 are described in JP-A-63-39377.
Detailed description thereof will be omitted.

An image forming apparatus of this embodiment using the reversible thermosensitive recording medium 70 described above will be described with reference to FIG.

FIG. 1 is a schematic configuration diagram of a photosensitive pressure-sensitive printer using the present invention.

As shown in FIG. 1, the photosensitive pressure-sensitive printer 101 uses photosensitive paper composed of photosensitive pressure-sensitive paper 12 (hereinafter referred to as microcapsule paper) and color-developing paper 28 (hereinafter referred to as recording paper). ..

An exposure unit 7 is provided above the printer 101.
1 is provided, and the cartridge 15 is provided below the exposure unit 71. As shown in FIG. 5, the details of the exposure unit 71 include an exposure system of RGB three colors, for recording information on a halogen lamp 53, a reflector 53a that collects the light of the lamps, and a reversible thermosensitive recording medium 70, respectively. Thermal head 73, reversible thermosensitive recording medium 70
Is made up of an erasing heat source 74 and a heat ray cutting glass 77 that make the entire surface cloudy.

Further, the microcapsule paper 12 is structured to pass between the reversible thermosensitive recording medium 70 and the exposure table 11. Therefore, the light emitted downward from the halogen lamp 53 and the reflector 53a is controlled in exposure amount by the reversible thermosensitive recording medium 70 to form a latent image on the microcapsule paper 12. On the other hand, the printer 10
A cartridge 15 is disposed in the center of the cartridge 1, and the long microcapsule paper 12 is accommodated in a cartridge 15 that is removable from the machine body while being wound around a cartridge shaft 14.

The tip of the microcapsule paper 12 is pulled out toward the exposure table 11 while the cartridge 15 is set at a predetermined position inside the machine body. A feed roller 19 and a dancer roller 21 for tension adjustment are arranged on the lower left side of the exposure table 11.

On the right side of the dancer roller 21, a pressure developing device 22 having a large diameter roller 22a and a backup roller 22b is arranged, and the pressure developing device 22 is provided.
On the right side of the separation roller 23 for separating the microcapsule paper 12 and the color-developing paper 28, which are adhered to each other, as described later.
Is provided, and the separation roller 23 and the cartridge 1 are provided.
A winding shaft 24 for fitting and holding the microcapsule paper 12 is arranged between the winding shaft 24 and the microcapsule 5. Cartridge 15
The microcapsule paper 12 coming out of the upper part of the table is guided to the feed roller 19, passes above the exposure table 11, passes the dancer roller 21 and the pressure developing device 22, and is further guided to the separation roller 23. It is wound around the winding shaft 24. The unexposed microcapsule paper 12 that has left the cartridge 15 is kept in an unexposed state by the light-shielding cover. Below the pressure developing device 22, a paper feeding cassette 29 accommodating the color developing paper 28 is mounted. Above the paper feed cassette 29, a suction cup-type paper feed mechanism 30 that attracts paper by using negative pressure suction is arranged, and the color-developed papers 28 are taken out one by one by the paper feed mechanism 30.

A feed guide 31d, feed rollers 31a, 31b, and 3 are provided between the paper feed mechanism 30 and the pressure developing device 22.
1c is provided, and the color-developing paper 28 is a feed roller 31.
a, 31b, 31c, and the feed guide 31d, and are carried into the pressure developing device 22.

A thermal fixing device 32 is disposed on the right side of the pressure developing device 22, and a discharge tray 33 for storing the color-developed paper 28 on which an image is formed is disposed on the right side of the thermal fixing device 32. It is set up.

Further, this printer has an auto loading function for automatically setting the microcapsule paper 12 on a predetermined transport path in the apparatus. This is a function of automatically pulling out the leader film portion attached to the leading end portion of the microcapsule paper 12 into the device, transporting it inside the device, and winding it around the winding shaft 24. As a result, the microcapsule paper 12 following the leader film portion is also wound around the winding shaft 24, and the setting in the device is completed.

For this automatic loading, a half-moon roller 17 is provided between the feed roller 19 and the cartridge 15 for pulling out the leader film portion, and a separating chute 27 is provided for guiding the winding shaft 24.
Is rotatably attached. An upper winding guide 25 is arranged around the winding shaft 24 for winding the leader film.

Next, the operation of this printer will be described.

When the cartridge 15 is set in the printer 101, automatic loading is started.

The half-moon roller 17 rotates once to several times in the transport direction only when the automatic loading is started, and sends the leader film portion to the roller 20. Then stop,
The subsequent transportation is performed by driving the roller 20.

The upper winding guide 25 and the separating chute 27 are
The microcapsule paper 12 is rotated to the position shown by the alternate long and short dash line.
The leader film attached to the tip of the tape is wound around the take-up shaft 24 after the auto-loading is completed.
The upper winding guide 25 and the separation chute 27 are returned to the positions shown by the solid lines to enable output.

When the RGB data of the output image is sent to the printer input section (not shown), the printer 101 starts image formation. That is, based on the input data, RGB
The temperature of the thermal head 73 for each color is controlled to form a first latent image on the reversible thermosensitive recording medium 70. Then, the moving speed of the reversible thermosensitive recording medium 70 and the microcapsule paper 12 are synchronized with each other, and the respective colors are overlapped and exposed to form a second latent image on the microcapsule paper 12. That is, the reversible thermosensitive recording medium is conveyed at the same speed as the microcapsule paper 12, and the erasing heat source 74 first causes the reversible thermosensitive recording medium 70 to become cloudy.

When the sheet is further conveyed, the temperature of the thermal head 70 is controlled so that the reversible thermosensitive recording medium 70 has a light transmission amount according to the input data, and the first latent image is formed on the reversible thermosensitive recording medium. Record. After that, when passing under the halogen lamp 53, the amount of light reaching the microcapsule paper 12 is controlled by the reversible thermosensitive recording medium, and a second latent image is formed on the microcapsule paper 12. By carrying out the above-mentioned processing for the three colors of red, green and blue (RGB), a full-color latent image is formed on the microcapsule paper 12. Since the temperature of the thermal head is controlled for each pixel to form an image, the output image can be output in gray scale. Figure 6 shows the data flow at that time.
It will be explained based on.

As input data, output data from a computer or a scanner is used and transferred to the correction circuit 65 as 8-bit digital data of RGB. Correction circuit 6
At 5, conversion processing such as enlargement / reduction and partial color conversion is performed, and further, gamma characteristics of the microcapsule paper 12 are corrected and smoothing processing is performed. When the correction process is completed, the signals are sent to the buffer 66 for each of RGB, are sequentially transferred to the PWM control circuit 67, and PWM control is performed according to the values of each RGB, and the driver 69 drives the thermal head 73. That is, depending on the size of the RGB values, the thermal head 7
3 is controlled, and as a result, the temperature applied to the reversible thermosensitive recording medium 70 changes in proportion to the gradation characteristic. The buffer amount of the buffer 66 is provided to adjust that the image positions exposed at the same time are different depending on RGB because the positions of the RGB thermal heads are different. That is, when the R and G head positions are separated by 64 lines, the G buffer memory amount is larger than R by 64 lines. The same applies to the B buffer memory amount.

Microcapsule paper 12 on which a latent image is formed
Is conveyed, and the uppermost color-developed paper 28 of the paper feed cassette 29 is conveyed by the paper feed mechanism 30, the feed rollers 31a, 31b, 31c and the like.

The pressure developing device 22 is supplied with the microcapsule paper 12 and the color-developing paper 28 in close contact with each other in an integrated state, and the microcapsule surface on which the latent image of the microcapsule paper 12 is formed and the color-developing paper 28 are supplied. The developer application surface is integrally sandwiched between the large-diameter roller 22a and the backup roller 22b while being in contact with the inside, and pressure is applied. This pressure destroys the unexposed microcapsule paper, and an image is formed on the color developing paper 28.

The microcapsule paper 12 and the color-developing paper 28 discharged from the pressure developing device 22 are separated by the separating roller 23, and then the color-developing paper 28 is heated by the heat roller 3 of the heat fixing device 32.
After the color development is promoted by 2a to form an image, it is carried out to the paper discharge tray 33 by the paper discharge roller 32b. still,
The separated microcapsule paper 12 is taken up by a take-up shaft 24 via a separating roller 23. The reversible thermosensitive recording medium 70 is rewound each time an image is formed, and is ready for the next exposure.

A color copier can be easily constructed by combining the printer and the color scanner.

Here, when all the microcapsule paper 12 is used, it is wound around the winding shaft 24 to replace the cartridge. Since the microcapsule paper 12 and the reversible thermosensitive recording medium 70 are integrally formed in the cartridge, the reversible thermosensitive recording medium 70 is replaced with a new one when the microcapsule paper is replaced. It is sufficient if the cartridge has a life of one roll.

[0046]

As is clear from the above description, according to the present invention, a photosensitive recording medium capable of expressing a halftone,
Since a reversible thermosensitive recording medium is used as a light control medium to form an image on a photosensitive recording medium, it is possible to provide an image forming apparatus with high resolution and high gradation.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a photosensitive pressure-sensitive printer.

FIG. 2 is a cross-sectional view of a thermoreversible display sheet.

FIG. 3 is an explanatory diagram showing a transparent state and a cloudy state of the thermoreversible display sheet.

FIG. 4 is an explanatory diagram showing thermoreversible characteristics of a thermoreversible display sheet.

FIG. 5 is a configuration diagram of a light and pressure sensitive printer exposure unit.

FIG. 6 is an explanatory diagram showing a data flow.

FIG. 7 is a schematic configuration diagram of a conventional analog photosensitive pressure-sensitive copying machine.

FIG. 8 is a schematic configuration diagram of a conventional static exposure full-color printer.

[Explanation of symbols]

 12 microcapsule paper 15 cartridge 70 reversible thermosensitive recording medium 101 photosensitive pressure-sensitive printer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // B41J 2/445

Claims (1)

Claim: What is claimed is: 1. An image forming apparatus comprising: a light source for irradiating a moving photosensitive recording medium with light necessary for exposing the photosensitive recording medium; and a thermal control unit capable of controlling temperature for each pixel. A reversible thermosensitive recording medium and the photosensitive recording medium are brought into close contact with each other and moved at the same speed, and the reversible thermosensitive recording medium uses the thermal control means to form a first latent image by density gradation; The photosensitive recording medium and the reversible thermosensitive recording medium are brought into close contact with each other, light is emitted from the light source, and a means for forming a second latent image on the photosensitive recording medium by the transmitted light of the first latent image is provided. Image forming apparatus.