JPH01105906A - Exposing device - Google Patents

Abstract

PURPOSE:To obtain a stable rotating speed even at the time of a low speed rotation and to reduce the fluctuation of a picture element position by attaching coaxially a stabilizing member to a rotation axis of a polygon mirror. CONSTITUTION:To the lower part of a rotation axis 271 of a polygon mirror 270, a motor 272 is fixed, and to the upper part, a stabilizing member 273 is attached. The stabilizing member 273 is formed in a columnar shape, an annular shape, etc., by which a dynamic balance can be taken easily, by a material of iron, phosphor bronze, etc. By attaching this stabilizing member 273, the inertia capacity of a motor load increases even at the time of a low speed rotation and a stable rotating speed can be shown. For instance, when said member is an annular shape of 52mm outside diameter and 2mm thickness and its rotating speed is 1,000rpm, the maximum fluctuation of a picture element position is 30mum, and can be decreased remarkably, comparing with 100mum at the time when said member is not installed.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an exposure device in an image recording apparatus that records an image on a photosensitive material, and is suitable for digital exposure using a laser beam scanner using a polygon mirror. The present invention relates to an exposure apparatus used for.

<Prior art and its problems> An image recording method is known in which an image is recorded using a photosensitive material having a support coated with a substance on which an image formed by imagewise exposure is fixed by pressure.

Examples of photosensitive materials used in such image recording methods include those that utilize microcapsules containing a photosensitive composition, such as synthetic materials containing a vinyl compound, a photopolymerization initiator, and a young coloring agent precursor. A photosensitive material using a polymer resin wall capsule has been disclosed (Japanese Patent Laid-Open No. 179836/1983).

This photosensitive material forms a color image from a colorant precursor that is imagewise cured by exposing the microcapsules to light, then pressurized to rupture the uncured microcapsules and released. It has the characteristic of being able to obtain high quality images through processing.

However, this light-sensitive material has lower photosensitivity than light-sensitive materials using silver halide, such as photographic emulsions.

Therefore, a new photosensitive material has been disclosed that has higher photosensitivity and makes it possible to obtain high-quality images through simple dry processing (Japanese Patent Laid-Open No. 61-275742).
In this light-sensitive material, at least a photosensitive silver halide, a reducing agent, a polymerizable compound, and a color image-forming substance are coated on a support, and at least the polymerizable compound and the color image-forming substance are coated on a support. It is enclosed in a capsule.

An image recording apparatus that records images using such a photosensitive material is disclosed in detail in Japanese Patent Laid-Open No. 147461/1983.

That is, in this image recording apparatus, first, imagewise exposure is performed to form a latent image on the photosensitive material.

Next, this photosensitive material is subjected to a development process by heating, and the polymerizable compound in the area where the latent image is present is polymerized to produce a high molecular compound, thereby hardening the microcapsules. Finally, this photosensitive material and an image-receiving material having an image-receiving layer to which a color image-forming substance can be transferred are stacked and pressed together to rupture at least a portion of the microcapsules in areas where no latent image exists, thereby forming a color image. A forming substance is transferred to the image receiving material to form a visible image.

The exposure device in the image recording apparatus described in the above-mentioned publication employs a so-called analog image exposure method in which a fiber lens array is used for direct exposure with reflected light from a light source.

However, the analog image exposure method is not suitable when image processing is required, so a so-called digital image exposure method is used, in which exposure is performed indirectly using a combination of a laser, modulator, and scanner based on the image electrical signal. It is preferable to do so.

In such a digital image exposure method, a polygon mirror is commonly used as a means for deflecting a laser beam for scanning and exposing a photosensitive material. In this case, the scanning speed of the laser beam is determined by taking into account the transport speed of the photosensitive material, the exposure power, and the scanning density.

Polygon mirrors are stable when rotating at high speeds, but when rotating at low speeds, there is a drawback that rotational speed unevenness increases and pixel position fluctuations occur.In order to obtain stable rotation with a small motor, the rotation speed must be 5000 rpm or more. It is desirable that

The scanning speed is expressed by the relational expression: (number of rotations) x (number of faces of polygon mirror).If the number of faces is decreased, the number of revolutions can be increased, but if the number of faces is decreased, the effective scanning time will be reduced. The disadvantage is that the ratio decreases. Therefore, in reality, those having 8 or 6 sides are commonly used.

Therefore, for example, in order to obtain a stable image with a polygon mirror having six faces, an exposure power that satisfies a scanning speed of 5000760 x 6 = 500 (scanning line 7 seconds) or more is required.

Therefore, if sufficient exposure power is not obtained, pixel position fluctuations (jitter) occur. In addition, the permissible amount of fluctuation in pixel position is about ±1/2 pixel, for example, 1/2 pixel.
In the case of 400 dots per inch, it is ±31.7 μm.

For this reason, it is desired to prevent fluctuations in pixel positions even when the exposure power is low and the rotation speed of the polygon mirror is low.

<Objective of the Invention> The object of the present invention is to apply a polygon mirror that can obtain a stable rotational speed even during low-speed rotation, thereby reducing fluctuations in pixel position, and is advantageous in terms of cost. The purpose of the present invention is to provide an exposure device.

<Brief explanation of the invention> Such objects are achieved by the invention described below.

That is, the present invention is an apparatus that exposes a photosensitive material by irradiating it with laser light, and includes a polygon mirror that deflects the laser light that is irradiated onto the photosensitive material, and a motor that rotates the polygon mirror. This is an exposure apparatus characterized in that a stabilizing member is fixed coaxially with the.

<Specific structure of the invention> Hereinafter, a specific configuration of the present invention will be explained in detail.

FIG. 1 and FIG. 2 are configuration diagrams for explaining an embodiment of an exposure apparatus according to the present invention.

FIG. 1 shows a color exposure apparatus for obtaining color images, and FIG. 2 shows a monochrome exposure apparatus for obtaining monochrome images.

As shown in FIG. 1, the exposure amount of each color is controlled by an exposure control circuit in the image processing device 4, and digital/
It is converted into an electrical signal by an analog conversion circuit, and this electrical signal (image information) is transmitted to the semiconductor laser 251, 252, 253, 254 of the exposure apparatus 1 of the present invention,
Red, green, and blue laser beams are emitted, respectively.

The red light is generated by a semiconductor laser 251 that emits a laser beam with a wavelength of 1300 nm, and a second harmonic generation element (hereinafter referred to as an SHG element) 25 that converts the wavelength of this laser beam to 1/2.
Formed by 5. The semiconductor laser 251 is, for example, NDL5004 manufactured by NEC Corporation. The SHG element 255 is a LINbO3 optical waveguide type element, and outputs a red light beam having a wavelength of 650 nm by halving the wavelength of the incident laser light. The laser beam with a wavelength of 650r++n emitted from the SHG element 255 passes through the collimator lens 25.
8 and is reflected by a total reflection mirror 261 toward a polygon mirror 270.

The green light is excited by the semiconductor laser 252 and the Nd:YAG
The laser beam with a wavelength of 11064n emitted by the crystal 254 is
It is formed by converting the wavelength to 1/2 by the SHG element 256. The laser beam emitted from the Nd:YAG crystal 254 is converted into a wavelength of 532r+m by the SHG element 256, and shaped through the collimator lens 259, and then the dichroic mirror 2 passes the red light and reflects the green light.
62 toward the polygon mirror 270.

The blue light is produced by a semiconductor laser 253 that emits a laser beam with a wavelength of 850 nm and an SH that converts this laser beam into half.
It is formed by the G element 257. Semiconductor laser 25
3 is, for example, NDL3108 manufactured by Nippon Kata Kyikisha.
Laser light with a wavelength of 425 nm emitted by the SHG element 257 is shaped through a collimator lens 260 and reflected toward a polygon mirror 270 by a dichroic mirror 263 that passes red and green light and reflects blue light.

The above-mentioned red light, green light, and blue light pass through the same optical path 264 and are reflected by the polygon mirror 270, and are reflected by the fθ lens 280.
The light is further reflected by a mirror 290 and reaches the photosensitive material S.

As the polygon mirror 270 rotates around the shaft 271, the image light scans and exposes the photosensitive material S.

Furthermore, in the exposure apparatus 10 having the embodiment shown in FIG. 312, and a laser beam is emitted.

Laser light with a wavelength of 780 nm emitted from the semiconductor laser 312 passes through a collimator lens 313 and is shaped.
It is reflected by the rotating polygon mirror 270, and f
The light passes through the θ lens 316, is reflected by a mirror 317, and reaches the photosensitive material S.

Here, the semiconductor laser 312 is, for example, H manufactured by Hitachi, Ltd.
L7801E etc. can be used.

At this time, as the polygon mirror 270 rotates, the laser beam scans and exposes the photosensitive material S.

The polygon mirror 270 used in the present invention has a stabilizing member fixed thereto.

For example, as shown in Figure 3,
A motor 272 for rotating the polygon mirror 270 is arranged below it, and a stabilizing member 273 is arranged above it. In this case, the polygon mirror 270, the motor 272, and the stabilizing member 273 are rotatably fixed coaxially to the shaft 271.

Further, as shown in FIG. 4, a motor 272 is disposed on the lower surface of a polygon mirror 270 installed on a support body 279, and a stabilizing member 273 is disposed on the lower surface of this motor 272, and these components are rotatably coaxially connected to a shaft 271. A fixed configuration may also be used.

Note that the rotation speed of the polygon mirror 270 is 1000 r
It is about pm.

The polygon mirror 270 is usually a prismatic body with 6 or 8 faces, a diagonal diameter of about 40 mm, and a height (thickness) of 4 mm.
~5IIIm.

The material is aluminum or the like, which is mirror-polished.

The stabilizing member 273 has a shape such as a cylinder, a torus, a cone, etc. that allows dynamic balance to be easily adjusted, and a cylinder is particularly preferable, and in the embodiment shown in FIG. The bottom diameter is 40 to 50 mm, the height (
It is sufficient if the thickness (thickness) is about 10 mm and the density is about 7 g7 cm" or more.

The material of the stabilizing member 273 is preferably a material with high density, such as iron, phosphor bronze, or brass.

The motor 272 is not particularly limited, and a commercially available motor can be used.

Polygon mirror 270, motor 272, and stabilizing member 27
3 means that if it is fixed coaxially and is configured to be rotatable,
There is no limit, polygon mirror 270, stabilizing member 273
may be arranged with a gap or without a gap.

Further, as shown in FIGS. 5 and 6, the polygon mirror 270, motor 272, and stabilizing member 273 are
The arrangement may be substantially the same as that shown in the figure, the whole being covered with a housing 278, the motor 2 and the fan 2 being fixed to the housing, and the upper and lower ends of the shaft 271 being supported by bearings 275 and 275. By supporting the bearings 275, 275 in this manner, shaft wobbling can be kept to a minimum.

In addition, as shown in FIGS. 7 and 8, the support 279
An annular stabilizing member 273 is fixed to the outer periphery of the rotor of a motor 272 installed in the
70 may be arranged coaxially. Note that the rotating shaft 271 of the rotor of the motor 270 is connected to the support 279 and the motor 270.
The stator is supported by a radial bearing 276 and a thrust bearing 277.

In the digital exposure, an SHG element is used to obtain red, green, and blue light from a semiconductor laser light source.
By using a photosensitive material that has a photosensitive wavelength range in the infrared region, such as the material shown in No. 277092, some or all of the three types of exposure can be performed in the infrared region, thereby eliminating the need for SHG elements. becomes possible.

FIG. 9 shows the exposure device 1 (
When obtaining a monochrome image, the exposure device 10) is
2-209461 and Japanese Unexamined Patent Publication No. 62-147461, in which the present invention is applied to an image recording apparatus.

Note that the exposure device in the illustrated example of the image recording device described in the above publication employs an analog image exposure method,
An embodiment is mentioned in which there is no need to install an image reading device and an image processing device because direct exposure is performed using reflected light from a light source.

In the block diagram shown here, the exposure device is converted into a digital image exposure method according to the present invention.

The image reading device and the image processing device may be of a known type, and for example, the type described in Japanese Patent Application No. 315536/1983 is used.

Note that this image recording device is disclosed in Japanese Patent Application No. 62-121284.
This method automatically performs the image forming method as disclosed in the patent specification. In this case, first perform imagewise exposure to form a latent image, then develop it by heating.
, the microcapsule is cured by polymerizing the polymerizable compound in the area where the latent image is present to produce a polymer compound. Then, the image-receiving material having an image-receiving layer to which the color image-forming substance can be transferred is stacked and pressurized to rupture at least a portion of the microcapsules in the area where the latent image does not exist, and the color image-forming substance is transferred to the image-receiving material. to obtain an image on the image-receiving material.

The image recording apparatus shown in FIG. ), an exposure device 1 that imagewise exposes the photosensitive material S conveyed from ), a thermal development device 5 that heats and develops the imagewise exposed photosensitive material, an image-receiving material storage section 2 (C), and a photosensitive material that has been heat-developed. A pressure transfer device 6 after superimposing the image-receiving material and a peeling device 7 provided downstream of the pressure transfer device
, and further includes a photosensitive material disposal section 8 and a fixing device 9 provided downstream thereof.

Although the image recording apparatus of the above embodiment is configured to perform the thermal development process and the pressure transfer process separately, it may be configured to perform the thermal development transfer process simultaneously.

In addition, various configurations can be selected depending on the purpose and use.

Further, in the above embodiment, the fixing device 9 is provided, but it may be selected as appropriate depending on the photographic material used.
Depending on the case, a configuration may be adopted in which the fixing device 9 is not provided. For example, a post-heating device may be installed to improve image density.

In the image recording apparatus shown in FIG. 9, a photographic material in which a photosensitive material as a photosensitive element and an image receiving material as an image receiving element are provided on separate supports is used. The elements may be formed on the same support. Furthermore, although an example is taken in which both are peeled off after transfer, a type that does not require peeling may also be used.

In general, the following photosensitive materials can be used in an image recording apparatus having an exposure device of the present invention.

For example, there is a type of photosensitive material disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 57-179836 in which a polymerizable compound is imagewise cured by imagewise exposure and then pressure is applied to obtain a visible image. This photosensitive material has a synthetic polymer resin wall capsule containing a vinyl compound, a photopolymerization initiator, and a colored precursor supported on a support.

Another example is a type in which a visible image is obtained by applying pressure after preliminary thermal development or wet development of a latent image generated by imagewise exposure.

Examples of such materials include Japanese Patent Application Laid-open No. 6, published by the present applicant.
Publication number 1-278849 or patent application No. 1988-5388
Examples include the materials shown in Specification No. 1. The material disclosed in JP-A No. 61-278849 is a material in which a color image-forming substance is transferred to an image-receiving material having an image-receiving layer after thermal development to obtain an image on the image-receiving material. is coated with at least a photosensitive silver halide, a reducing agent, a polymerizable compound, and a color image forming substance, and at least the polymerizable compound and the color image forming substance are encapsulated in the same microcapsule. This photosensitive material is
Preferably used in the present invention.

Furthermore, the material disclosed in the above-mentioned Japanese Patent Application No. 61-53881 is for obtaining an image on a photosensitive material without using an image-receiving material. In other words, the image-receiving layer is provided on the photosensitive material itself, and contains silver halide, a reducing agent, a polymerizable compound, and two types of substances that cause a color reaction when in contact with one of the substances that cause a color reaction. A photosensitive layer in which the polymerizable compound is contained in microcapsules, and other substances among the substances that cause a color reaction are present outside the microcapsules containing the polymerizable compound, is placed on the support. This is what we have. In the present invention, this photosensitive material is also preferably used.

The present invention, when combined with such a photosensitive material, can eliminate drawbacks such as insufficient sensitivity at high speed rotation and a decrease in sensitivity due to short exposure (reciprocity law failure).
This has the advantage that good images can be recorded.

In addition, the exposure apparatus of the present invention can be used for exposing various other photosensitive materials.

<Specific action of the invention> The specific operation of the exposure apparatus of the present invention will be described below.

When obtaining a color image using a color photosensitive material according to the image information of the image processing device 4, the exposure device 1 of the present invention performs (
When a monochrome image is obtained using a monochrome photosensitive material, the photosensitive material S transported from the storage section 2 (S) for the photosensitive material S is imagewise exposed (in the exposure device 10).

In this case, as the polygon mirror 270 rotates around the axis 271, the image light (laser light) scans and exposes the photosensitive material S.

The polygon mirror 270 in the present invention is shown in FIGS.
As shown in the figure, a stabilizing member 273 is installed, and the inertial capacity of the motor load increases even during low-speed rotation (for example, 1000 rpm), resulting in a stable rotational speed.

The photosensitive material S imagewise exposed in this manner is carried into a thermal developing device 5 and is thermally developed.

<Effects of the Invention> The polygon mirror of the present invention can obtain a stable rotational speed even during low-speed rotation. As a result, fluctuations in pixel positions can be reduced.

Furthermore, motors, stabilizing members, etc. made of common materials can be used, which is advantageous in terms of cost.

The present inventor conducted various experiments in order to confirm such effects. An example is shown below.

Experimental example> A polygon mirror 270 as shown in FIGS. 7 and 8
The fluctuation of pixel position was investigated using

In this case, the polygon mirror 270 has 8 faces and a diameter of 4.
A mirror-polished aluminum plate with a diameter of 0 mm and a thickness of 2+ nm was used.

The stabilizing member 273 has a toric shape with an outer diameter of 52 mm and a thickness of 2 mm, and is made of C3603 (brass) (density 8,3 mm).
g/cm') was used.

The rotational speed of the motor was 1000 rpm.

Further, the laser power was 3 mW, and the photoreceptor feeding speed was 30 mm/sec.

The photoreceptor used was an A4 size one, and a straight line was recorded at the farthest position from the SOS sensor (right edge of the screen) within 210 mm during effective scanning in the laser beam scanning direction, and the fluctuation was measured. The positional fluctuation was 30 μm, which was within the permissible amount of pixel position fluctuation of ±1/2 pixel at 400 dpi, ±31.75 μm.

On the other hand, fluctuations were measured under the same conditions as above using a polygon mirror having the same configuration as the polygon mirror of the present invention except that the stabilizing member 273 was not installed.
The fluctuation in pixel position was 100 μm, which exceeded the allowable amount.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are configuration diagrams for explaining aspects of the exposure apparatus of the present invention, respectively. FIG. 3 is a perspective view showing an aspect of the polygon mirror according to the present invention. FIG. 4 is a front view showing an aspect of the polygon mirror in the present invention. □ FIG. 5 is a perspective view showing an aspect of the polygon mirror according to the present invention, and FIG. 6 is a front view showing a portion thereof in cross section. FIG. 7 is a perspective view showing an aspect of the polygon mirror according to the present invention, and FIG. 8 is a front view showing a portion thereof in cross section. FIG. 9 is a block diagram of an image recording apparatus equipped with an exposure apparatus of the present invention. Explanation of symbols S...Photosensitive material, 1(10)...Exposure device, 2(S)...Accommodating section for photosensitive material, 3...Image reading device, 4...Image processing device, 5 ...Thermal development device, 2(C)... Image receiving material storage section, 6... Pressure transfer device, 7... Peeling device, 8... Sensitive material disposal section, 9... Fixing device, 251.252.253.312...semiconductor laser, 254...Nd:YAG crystal, 255.256.257...SHG element, 258,
259, 260, 313...Collimator lens, 261...Total reflection mirror, 262.263...Dichroic mirror, 264...
- Optical path, 270... Polygon mirror, 271... Axis, 272... Motor, 273... Stabilizing member, 275.276.277... Bearing, 280.3
16... fθ lens, 290.317... Mirror FIG, 1 FIG, 2 FIG, 4 FIG, 6 FIG, 7

Claims (3)

[Claims] (1) An apparatus that exposes a photosensitive material by irradiating it with laser light, which includes a polygon mirror that deflects the laser light that is irradiated onto the photosensitive material, and a motor that rotates the polygon mirror. An exposure apparatus characterized in that a stabilizing member is fixed to the. (2) The photosensitive material is a photosensitive pressure-sensitive heat-developable material having on a support a photosensitive layer configured such that an image formed by heat development after imagewise exposure is fixed by pressure. Exposure apparatus according to scope 1. (3) The exposure apparatus according to claim 2, wherein the image of the photosensitive pressure-sensitive heat-developable material is formed by a distribution of microcapsules having different degrees of curing after the heat development.