JPH01182853A - Image forming device with pressurizing speed variable function - Google Patents

Abstract

PURPOSE:To form a satisfactory image corresponding to an image receiving sheet by setting the speed, at which the image receiving sheet passes a pressing part, in accordance with the type of the image receiving sheet. CONSTITUTION:The speed at which a light receptive sheet and the image receiving sheet pass a pressure part 3 is directly inputted, or the type of the image receptive sheet is inputted and said speed is set in accordance with this type. Consequently, the passage speed corresponding to the type of the image receptive sheet or the type of the image receptive sheet is inputted to properly set a maximum density, a minimum density, and the gamma of a developed image in accordance with this type. Thus, a satisfactory developed image is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Field of Application The present invention provides a photoreceptive sheet on which a selectively cured image is formed by photosensitive and pressure-sensitive microcapsules, and a photoreceptive sheet that is superimposed on the photoreceptive sheet and pressurized. The present invention relates to an image forming apparatus including an image receiving sheet on which a colored image is formed.

(b) Conventional technology A light-receiving sheet in which a photocurable material, a photosensitive pressure-sensitive microcapsule containing a colorless dye encapsulated in a resin shell, is coated on polyester or the like, and a base sheet is coated with a developing material that develops color from the colorless dye. JP-A-58-88739 discloses a method of forming an image using an image-receiving sheet. Note that the base sheet of the image receiving sheet "
Thin paper of about 90g/rrf or less, 90~
Ordinary paper of about 120 g/rd, thick paper of about 120 g/rd or more, or OHP (Over-Head Projector) paper is used.

When the light-receiving sheet is image-formingly exposed to light reflected from the original, the microcapsules are partially cured and a selectively cured image is formed. When the image-receiving sheet is superimposed on the light-receiving sheet and pressurized, the uncured microcapsules are cleaved and the colorless dye flows out, causing a coloring reaction with the developing material of the image-receiving sheet to form a colored image.

In order to cleave the uncured microcapsules, 2
A high pressure of about 5 to 125 kg/am is required, and in order to apply such high pressure, it is efficient to pass the material between pressure rollers that are in contact with each other.

For such pressure rollers, see USP4399209.
No. 62-6257.

(C) Problems to be Solved by the Invention When a light-receiving sheet and an image-receiving sheet are overlapped and pressed to cleave uncured microcapsules, if the pressurized state is unstable, the microcapsules will not be cleaved properly. The density of the colored image sometimes changed. For example, instability in the pressurized state is due to the type of base sheet of the image-receiving sheet; even if pressure is applied using the same device, if the base sheet is thin, the density will be low, and if the base sheet is thick, the density will be low. It was dark (it was dark).
No. 5 and Japanese Patent Application Laid-Open No. 62-209536, a method was proposed in which the rotational speed and pressing force of the pressure roller were controlled according to the original density and input from a density selection switch, etc. These methods did not deal with the instability of the pressurized state.

In view of the above-mentioned drawbacks, this invention makes it possible to form a good image corresponding to the image-receiving sheet by making it possible to set the speed at which the image-receiving sheet passes through the pressure section according to the type of the image-receiving sheet. An object of the present invention is to provide an image forming apparatus having a pressurization speed variable function.

(C) Means for Solving the Problems The image forming apparatus of the present invention having a variable pressurizing speed function has the following features:
A light-receiving sheet coated with photosensitive and pressure-sensitive microcapsules containing a colorless dye and an image-receiving sheet coated with a developing material that develops color from the colorless dye are superimposed, and the microcapsules are pressed by a pressure section. In an image forming apparatus that forms a colored image using a colorless dye by splitting a capsule, means for inputting a speed at which the light-receiving sheet or image-receiving sheet passes through the pressure section, or means for inputting the type of the image-receiving sheet. and a means for setting the speed at which the light-receiving sheet and the image-receiving sheet pass through the pressure section according to the input type of image-receiving sheet.

(e) Effect According to experiments conducted by the present inventors, by slowing down the speed at which the light-receiving sheet and the image-receiving sheet pass through the pressurizing section, ■ the maximum density of the colored image becomes high, and ■ the minimum density of the colored image increases. It was found that there is a tendency for the density to increase, and the gamma of the colored image to increase (resulting in a high-contrast image quality).In the image forming apparatus of this invention, the light-receiving sheet and the image-receiving sheet pass through the pressure section The speed is entered directly or the type of receiver sheet is entered depending on the type of light receiving sheet.

The speed at which the image receiving sheet passes through the pressure section is set. Therefore, by inputting the passing speed according to the type of image receiving sheet or the type of image receiving sheet,
The maximum density, minimum density, and gamma of the colored image are set to be appropriate depending on the type, and a good colored image can be formed.

(f) Embodiment FIG. 2 is a diagram showing a schematic configuration of a copying machine which is an embodiment of the present invention.

A light-receiving sheet storage cassette 1 for storing light-receiving sheets is attached to the lower right portion of the main body of the copying machine. One end of the light receiving sheet is pulled out from the light receiving sheet storage cassette,
The sheet is wound onto a take-up roller 4 via a sheet support stand 2, a pressure roller 3, and a conveyance roller 41. A document table 5 is provided on the top surface of the copying machine main body, on which a document to be copied is placed.

A light source 51 is provided below the document table 5. An optical system including mirrors 52 to 55 and a lens 56 is provided to scan the document on the document table 5 and direct the reflected light to an exposure point P on the support table 2.
Lead to 1. This partially hardens the microcapsules and forms a selectively hardened image.

A paper feed cassette 6 is installed on the left side of the copying machine main body. An image receiving sheet is stored in the paper feed cassette 6.
The entire paper feed cassette 6 can be attached to and detached from the main body of the copying machine. The paper feed cassette 6 stores thin image receiving sheets, normal thickness image receiving sheets, thick image receiving sheets, and OHP image receiving sheets depending on the purpose. The image receiving sheet in the paper feed cassette 6 is fed by the paper feed roller 7, and is fed by the PS roller 8 to the pressure roller 3 at a predetermined timing, and is brought to the pressure point P2.
The photoreceptor sheet on which the selectively cured image has been formed is overlapped with the photoreceptor sheet and pressed. As a result, the uncured microcapsules are cleaved, the colorless dye flows out, and a colored image is formed. Thereafter, the image-receiving sheet is separated from the light-receiving sheet, heated by a heat roller 9, and discharged onto a paper discharge tray 11 by a paper discharge roller 10. Note that the coloring reaction is accelerated by heating the image receiving sheet on which the colored image is formed by the heat roller 9.
5), when the image-receiving sheet is coated with a thermoplastic pigment, the thermoplastic pigment softens or melts when heated, covers the surface of the colored image, and gives gloss to the colored image (Japanese Patent Laid-Open No. 60-1999). 259490).

The pressure roller 3 has an upper roller 31 and a lower roller 32 pressed against each other by a pressure contact mechanism (not shown), and the linear pressure thereof is approximately 25 to 125 kg/c+++. This pressure roller is connected to a drive system (not shown) and rotates, and its rotational speed is the pressure roller passing speed (pressure section passing speed). Note that the length between the exposure point P1 and the pressure point P2 is longer than the length of A3 size paper (pressure is started at the pressure point P2 after the image forming exposure at the light receiving sheet exposure point P1 is completed). Therefore, the exposure speed and the pressure roller passing speed can be set to different speeds.

FIG. 1 is a block diagram of the copying machine. The entire copying machine is controlled by the CPU 21, and its processing program is stored in the ROM 22 in advance. The RAM 23 is used as a working area when executing the processing program. On the other hand, an operation panel (not shown) is provided on the top surface of the copying machine main body, and includes an operation section including operation switches such as the speed input switch 24, and a display section for displaying input data and the like. The speed manual switch 24 is a switch for inputting the speed at which the light-receiving sheet and the image-receiving sheet pass through the pressure roller (pressure section) 3, and is composed of three types of switches 24a to 24c. These three types of switches 24
A to 24c are a low speed switch 24a, a medium speed switch 24b, and a high speed switch 24C, respectively. Input data from the speed input switch 24 is sent to the CPU 2 via l1025.
1 is input.

In response to the input from the speed input switch 24, the CPU 2
1 outputs control data to the rotational speed control circuit 27 of the pressure roller 3 via l1026. As a result, the three pressure rollers rotate according to the speed applied by the user.

With the copying machine configured as described above, the pressure roller passing speed is switched to three stages: low speed, medium speed, and high speed, and the speed of the pressure roller is changed to 0.1.
A copying experiment was conducted with a gray scale of 0 pitch and 0.05 to 1.85:a degrees. The image receiving sheet used at this time was a base sheet made of plain paper of about 110 g/rr. FIG. 3 is a diagram showing the results, in which the horizontal axis shows the exposure amount corresponding to the density of the gray scale, and the vertical axis shows the density of the colored image formed.

As is clear from the figure, the slower the pressure roller passing speed, the higher the maximum density of the colored image, the higher the minimum density of the colored image, and the larger the gamma (slope) of the colored image. There is a tendency for things to become harsh. By selecting the pressure roller passing speed according to the type of image-receiving sheet based on such a change tendency, it is possible to form a good image according to the type of image-receiving sheet used.

Therefore, we decided to change the type of base sheet of the image receiving sheet to a thick one (120g
/rrr), thin (90 g/m), and OHP, and the density of the image formed was examined by changing the pressure roller passing speed. Figure 4 shows the results, with the horizontal axis representing the pressure roller passing speed, and the vertical axis representing the maximum density of the colored image formed, i.e., whether the microcapsules of the light-receiving sheet were not cured. It shows the concentration of the part. Note that the reflection density is measured and expressed for thick and 1-size paper, but for OHP, transparency is required for its use, so the transmission density is measured and the results are shown.

As can be seen from the figure, when the base sheet of the image-receiving sheet is thick, a density of 1.4 or more can be obtained even if the pressure roller passing speed exceeds 90 n/sec. Further, when the base sheet is thin, the image density becomes less than 1.4 at approximately 6Q**/sec or more, and the image density becomes light and the image quality begins to deteriorate. Therefore, thick paper (120g
/ CD or more) is used as a base sheet, it is desirable to increase the pressure roller passage speed to about 90 W/sec according to the thickness (to make the copying process as fast as possible). 60-100g/rr
When the base sheet is made of a base sheet (approximately
0g/n? 60 to 90 m/sec for the thickness of
It is desirable to process at a pressure roller passing speed of about 100 mL.

On the other hand, in the case of OHP, if the transmission density is approximately 0.8 or higher, a sufficiently good projected image can be formed when projected with a projector, but if it is lower than approximately 0.8, the contrast of the projected image will be lost. Projected image quality deteriorates. In FIG. 4, when the pressure roller passing speed becomes approximately 60+n/sec or more, the transmission density becomes less than 0.8. Therefore, when OHP is used as a base sheet, the width is approximately 60 m/
It is desirable to pass the pressure roller at a speed of sec or less.

Based on such experimental results, if the pressure roller passing speed is inputted from the high-speed waste switch 24 according to the type of image-receiving sheet (substrate sheet), the pressure processing will be performed at an appropriate speed, resulting in a good result. You can get the image.

In this embodiment, the pressure roller passing speed is input directly from the speed input switch 24, but a switch for inputting the type of image-receiving sheet (substrate sheet) is provided, and the RAM 23 is also provided with a switch for inputting the type of image-receiving sheet (substrate sheet). The pressure roller passing speed may be stored, and the pressure roller passing speed may be determined simply by inputting a key for the type of image-receiving sheet. Alternatively, a detector for determining the type of image receiving sheet may be provided, and the pressure roller passing speed may be determined in accordance with the type of image receiving sheet detected by the detector.

The detector that determines the type of image-receiving sheet is one that detects the thickness of the image-receiving sheet, and one that detects whether the image-receiving sheet is plain paper or OH.
Two types of items are required to determine whether the item is P or not.

Examples of the detector for detecting the thickness of the image receiving sheet include: i) measuring the capacitance of the image receiving sheet ii) measuring the resistance of the image receiving sheet iii) measuring the light transmittance of the image receiving sheet, and measuring these values as the thickness of the image receiving sheet There is a way to convert it to . In other words, the thicker the thickness, the higher the i) capacitance, ii) the higher the resistance, and the higher the i)
n) Light transmittance becomes low.

Regarding the measuring method of i) and ii), as shown in FIG. The capacitance or electrical resistance can be measured between .82 and .82. In addition, to measure the light transmittance of iii),
As shown in FIG. 6(A), a transmission type optical sensor consisting of a light emitting element 12 and a light receiving element 13 is provided in the middle of conveying the image receiving sheet to detect the amount of transmitted light. Note that a microswitch 14 is provided in the front part of this optical sensor, and when this microswitch 14 is turned on, the light emitting element 1 is turned on.
2 turns on.

In addition, in order to determine whether the image receiving sheet is plain paper or OHP, there is a method of measuring the light transmittance of the image receiving sheet based on the light transmission characteristics of OHP. If so, the light transmittance will be high and the light reflectance will be low. The light transmittance of iv) is shown in the above-mentioned figure 6 (A
), it can be measured by using a transmission type optical sensor. In addition, as shown in FIG. 6(B), the light resistance of (■) is as follows:
2. Measurement can be performed by providing the light receiving element 13 on the same side as the light emitting element 12' and the light receiving element 13'.

In this way, the type of image receiving sheet (thickness, plain paper and OH
(difference from P).

This determination result is input to the CPU. The pressure roller passing speed (pressure roller rotation control data) corresponding to the type of image receiving sheet is stored in area M of the RAM 23', and the rotation of the pressure roller is adjusted according to the input type of image receiving sheet. Control data is output. Thereby, a good image can be formed depending on the type of image-receiving sheet.

In this way, by installing a detector that determines the type of image receiving sheet, it is possible to save the trouble of inputting the pressure roller passing speed and the type of image receiving sheet. Copying errors can be prevented.

In this embodiment, "means for inputting the speed at which the light-receiving sheet and image-receiving sheet pass through the pressure section (pressure roller)"
is input to the speed input switch 24, and the "means for inputting the type of image receiving sheet" is input from a type input switch (not shown) or to a device for measuring capacitance, resistance, light transmittance, light reflectance, etc.; "Means for setting the speed at which the light-receiving sheet and the image-receiving sheet pass through the pressurizing section according to the input type of image-receiving sheet" is located in area M of the RAM 23'.
Each corresponds to an arithmetic circuit that processes data stored in the .

(Effect of the Invention According to the image forming apparatus of the present invention, the pressure roller passing speed can be set according to the type of image-receiving sheet, so density unevenness occurs in the colored image due to different types of image-receiving sheet. This enables the formation of high-quality colored images.Also, when using a thick image-receiving sheet, the pressure roller passing speed can be set to a high speed, resulting in a high-quality color image. This has the advantage of increasing the copy processing speed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a copying machine which is an embodiment of the present invention.
Figure 2 is a schematic configuration diagram of the copying machine, Figure 3 is a diagram showing the density of a colored image formed when copying is performed with the same copying machine by changing the pressure roller passing speed, and Figure 4 is a diagram of the received image. FIG. 3 is a diagram showing the relationship between the type of sheet and the maximum density of a formed colored image. 5 and 6 are diagrams showing a method for determining the type of image-receiving sheet in another embodiment, and FIG. 5 is a diagram of a PS roller for measuring capacitance and resistance, A) is a diagram of an optical sensor that measures light transmittance, and (B) is a diagram of an optical sensor that measures light reflectance. 3-pressure roller, 12.12'-light emitting element, 13.13'-light receiving element, 24-speed input switch, 24a-low speed switch, 24b-medium speed switch, 24C-high speed switch, 81.82-conductive part .

Claims (1)

[Claims] (1) By overlapping a light-receiving sheet coated with photosensitive pressure-sensitive microcapsules containing a colorless dye and an image-receiving sheet coated with a developing material that develops color from the colorless dye, and applying pressure with a pressure section. , an image forming apparatus that cleaves the microcapsules to form a colored image using a colorless dye, comprising means for inputting a speed at which the light-receiving sheet and the image-receiving sheet pass through the pressure section; or means for inputting the type of the image-receiving sheet. A pressurizing speed variable function characterized by comprising: means for inputting, and means for setting the speed at which the light-receiving sheet and the image-receiving sheet pass through the pressurizing section according to the type of the inputted image-receiving sheet. An image forming apparatus having: