JPH0367668A - Exposure head - Google Patents

Abstract

PURPOSE:To prevent a flare light from being emitted from an emission port by a light shielding part by a method wherein the light shielding part provided with an open part having a diameter smaller than the effective diameter of an optical system and approximately equal to that of a luminous flux to be emitted is provided on the light emission part of a lens barrel. CONSTITUTION:A rib 86 is provided on an emission port 84 of a lens barrel 70 forming an exposure head 22. An open diameter D1 made of the rib 86 is smaller than an effective diameter D3 of a lens 82. The open diameter D1 is further reduced by the amount corresponding to a dimension L to be approximately equal to a diameter of a luminous flux, which is gradually reduced in diameter through the lens 82. In this manner, a flare light caused by the distortion of the lens 82 or the like is shielded by the rib 86. Therefore, a beam emitted from the exposure head 22 can record only a pixel of a high density required for an image recording, and the bleeding of pixels caused by a flare light is prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an exposure head that condenses light rays emitted from a light source using an optical system and forms an image of the light rays on a recording material to record an image. Regarding.

[Prior art]

Image recording in which an image is exposed onto a heat-developable photosensitive material, the heat-developable photosensitive material is superimposed on an image-receiving material, and heated, whereby the heat-developable photosensitive material is thermally developed and the image is transferred to the image-receiving material to obtain an image. The device is known.

In this type of image recording apparatus, when exposing a photothermographic material, the photothermographic material is wound around an exposure drum, and the exposure drum is rotated at high speed (main scanning). In this state, exposure is performed while moving the exposure head in the axial direction of the exposure drum (sub-scanning). In addition, the image recording device is equipped with a heating drum and an endless pressure belt that presses against the outer periphery of the heating drum.Furthermore, near the endless pressure belt, there is a rubber overlapping roller that contacts the outer periphery of the heating drum. is located. The image-exposed photothermographic material is superimposed on the image-receiving material by the superimposing roller, and then fed between the heating drum and the endless pressure belt.

As shown in FIG. 4, the exposure head 92 has its lens barrel 9.
3 has a light source 94 such as an LED chip and a lens 95, and the light rays emitted from the light source 94 are focused by the lens 95, and emitted from the exit port 96 of the lens barrel 93, and are then emitted onto the photothermographic material 97. I am trying to focus the image on the image.

[Problem to be solved by the invention]

However, among the light rays that have passed through the lens 95, in addition to the focused light ray bundle (see the solid line in Figure 4), there is also flare light (see the dashed line in Figure 4) caused by distortion of the lens 95, etc. It is emitted from. Therefore, as shown in FIG. 5, a low density area 99 exists around the high density area 98 of one pixel imaged on the photothermographic material 97, causing blurring in the image and degrading the image quality. become.

The present invention has been made in consideration of the above facts, and an object of the present invention is to obtain an exposure head that can obtain high-quality images without blurring due to flare light.

[Means to solve the problem]

An exposure head according to the present invention is an exposure head that records an image by condensing a light beam emitted from a light source by an optical system and forming an image of the light beam on a recording material, and the exposure head records an image by condensing a light beam emitted from a light source and forming an image on a recording material. a lens barrel to be held; a light shielding portion provided at an exit port of the light beam of the lens barrel and having an opening smaller than an effective diameter of the optical system and having a diameter substantially the same as a diameter of a bundle of light beams to be emitted;
have.

[Effect]

In the light beam emitted from the light source and passed through the optical system, there is flare light caused by distortion of the optical system, etc., in addition to the beam bundle focused on the recording material. In the present invention, this flare light is prevented from being emitted from the exit by the light shielding part. That is, the opening of the light shielding part is made to have the same diameter as the diameter of the beam of light to be recorded. In addition, since the diameter of the beam of light gradually decreases as it approaches the recording material, it is recommended to make the diameter of the aperture smaller than the effective diameter of the optical system and provide a light shielding part in the small diameter part as much as possible. preferable.

〔Example〕

FIG. 2 shows an image recording apparatus 10 according to this embodiment.

A magazine 14 is disposed on the machine base 12 of the image recording apparatus 10, and a roll-shaped photothermographic material 16 is housed within the magazine 14.

The heat-developable photosensitive material 16 is pulled out from its outer periphery, cut into a predetermined length by a cutter 18, and then wound around the outer periphery of a rotating drum 20 in the six directions of arrows.

An exposure head 22 is disposed corresponding to the outer periphery of the rotating drum 20, and rotates the rotating drum 20 at high speed to expose an image onto the wound photothermographic material 16.

After exposure, the photothermographic material 16 is transferred by rotating the rotating drum 20 in reverse (
In the direction of arrow B>, the scraper 24 scrapes the rotating drum 20.
After being peeled off from the film and being coated with water as an image grading solvent in a water application section 26, it is sent to a heat development transfer section 28, which is a heat development transfer device.

In the thermal development transfer section 28, a heating drum 34 and an endless pressure belt 36 serving as pressure contact means are arranged.

The heat-developable photosensitive material 16 coated with water is transferred to the heating drum 3
The heating drum 3 is supplied between the heating drum 3 and the endless pressure belt 36.
It is designed to be held and conveyed over approximately 2/3 of the circumference of 4 and thermally developed.

The endless pressure belt 36 is wrapped around the tension roller 37 near the part where the overlapping roller 60 is wrapped around the heating drum 34.
It is placed in a state where it is pressed against the outer periphery of.

On the other hand, a tray 30 disposed below the thermal development transfer section 28
Inside are a plurality of image receiving materials 3 cut to a predetermined size.
2 is accommodated. This image receiving material 32 is placed on a tray 30
The sheets are sequentially taken out one by one by a supply roller 44 disposed on the side of the sheet and sent to the thermal development transfer section 28.

The image receiving material 32 sent to the thermal development transfer section 28 is transferred by the overlapping roller 60 arranged in contact with the outer periphery of the heating drum 34 (between the overlapping roller 60 and the outer peripheral surface of the heating drum 34). It is superimposed on the photothermographic material 16 and is supplied between the heating drum 34 and the endless pressure belt 36 .

When the heat-developable photosensitive material 16 is heated while superimposed on the image-receiving material 32 in the heat-developable transfer section 28, it is thermally developed and the image is transferred to the image-receiving material 32, so that an image is obtained on the image-receiving material 32. It has become.

A pair of peeling claws 48 are disposed on the sides of the thermal development transfer section 28 so as to correspond to the outer circumferential surface of the heating drum 34 , and their tips slightly contact the outer circumferential surface of the heating drum 34 .

The peeling claw 48 moves together with the heating drum 34 and engages with the photothermographic material 16 located inside, thereby peeling the photothermographic material 16 together with the image receiving material 32 from the outer periphery of the heating drum 34. There is.

A pair of separation rollers 50 are arranged below the peeling claw 48 and correspond only to both ends of the image receiving material 32 in the width direction.
Furthermore, a conveyor belt 52 is wound around the separation roller 50. The conveyor belt 52 wound around the separating roller 50 engages only at both ends of the image receiving material 32 in the width direction, and separates the image receiving material 32 from the photothermographic material 16 and conveys it in a bent manner. .

The separated photothermographic material 16 is stored in a waste photosensitive material storage box 5.
The image-receiving material 32 is dried by a heater 54 and then delivered onto a take-out tray 56 formed at the top of the machine base 12.

As shown in FIG. 1, the exposure head 22 includes a cylindrical lens barrel 70 serving as its main body, and an optical system 72 is disposed at one end of the lens barrel 70. Further, a cylindrical stem 74 is attached to the other end of the lens barrel 70.

A substrate 76 is fixed to the inner peripheral surface of the stem 74.

An LED chip 80 serving as a light source is attached to the surface of the substrate 76 on the inner side of the lens barrel 70 via a base 78. By energizing this LED chip 80, the LED
The D-chip 80 emits light, and the light beam reaches the optical system 72 direction.

The optical system 72 is composed of a plurality of lenses 82, and emits the incident light beam from the LED chip 80 as a condensed beam. The exit opening 84 of the lens barrel 70 is formed with a rib 86 as a light shielding portion so that its opening diameter Dl is smaller than the inner circumferential diameter D2 of the intermediate portion of the lens barrel 70. A protrusion 88 is formed on the surface of the rib 86 on the inner side of the lens barrel 70, and supports the final stage lens 82. The inner peripheral diameter of this protrusion 88 is matched with the effective diameter D3 of the lens 82. Therefore, the projection 88 does not block the light rays that are imaged on the photothermographic material.

Also, the tip of this protrusion 88 (abutting part with the lens 82)
and the tip of the exit aperture 84 are separated by a certain dimension, and the diameter of the light beam emitted from the lens 82 is gradually reduced in accordance with this dimension (see the solid line in Figure 1). Dl is formed smaller than the effective diameter D3 of the lens 82, and has the same diameter as the diameter of the light beam.

The rib 86 has the role of blocking flare light (see the dashed line in FIG. 1) caused by distortion of the lens 82 among the light rays emitted from the lens 82 so that it does not exit from the exit port 84. Therefore, only the light beam that is imaged onto the photothermographic material 16 is emitted from the exit aperture 84 .

Next, the operation of this embodiment will be explained.

When the photothermographic material 16 pulled out from the magazine 14 is cut by the cutter 18 and wound around the outer circumference of the rotary drum 20, the rotary drum 20 rotates at high speed, and the exposure head 22 cuts the photothermographic material 1116 in the width direction. An image is exposed in the center.

Here, the lens barrel 70 constituting the exposure head 22 of this embodiment
A rib 86 is provided at the exit port 84 of the
The aperture diameter Dl formed by is the effective diameter D of the lens 82.
3, and the aperture Dl corresponding to the dimensions in FIG. The ribs 86 block flare light caused by distortion and the like. Therefore, the light beam emitted from the exposure head 22 can obtain pixels with only a high density necessary for image recording, and blurring of pixels caused by flare light can be prevented.

After exposure, the photothermographic material 16 is peeled off by a scraper 24, coated with water by a water coating section 26, and sent to a thermal development transfer section 28.

On the other hand, the image receiving material 32 in the tray 30 is taken out one by one by the supply roller 44, and further, the image receiving material 32 is taken out one by one by the supply roller 44, and
The heat-developable photosensitive material 16 is superimposed on the heat-developable photosensitive material 16 by the superimposing roller 60 disposed in
will be supplied between.

The heat-developable photosensitive material 16 and the image-receiving material 32 sent to the heat-develop transfer unit 28 are heated to about 90° C. by a halogen lamp 38 while being superimposed on a heating drum 34.
and the endless crimping belt 36, approximately two parts of the heating drum 34
The photothermographic material 16 is pinched and conveyed for three rounds to be thermally developed, and the image recorded on the photothermographic material 16 is transferred to the image receiving material 32.

After the transfer, the peeling claw 48 moves together with the heating drum 34 and engages with the heat-developable photosensitive material 16 located inside, and removes the heat-developable photosensitive material 16 along with the image-receiving material 32 to the heating drum 34.
Peel it off from the outer periphery.

The image receiving material 32 peeled off from the outer periphery of the heating drum 34 is
It is separated from the photothermographic material 16 by a conveyor belt 52 wrapped around a separation roller 50 and taken out to a takeout tray 56 via a heater 54 . On the other hand, the heat-developable photosensitive material 16 is sent to a waste photosensitive material storage box 59.

In this embodiment, the lens barrel 70 that constitutes the exposure head 22
A rib 86 is provided at the tip of the lens, and this rib 86 makes the aperture diameter D+ of the exit port 84 as small as possible, thereby eliminating leakage of flare light and preventing pixel blurring during image recording. .

In this embodiment, a rib 86 is provided at the tip of the lens barrel 70, and this is used as a light shielding part, but as shown in FIG. You can also get the same effect.

〔Effect of the invention〕

As explained above, the exposure head according to the present invention has the excellent effect of being able to obtain high-quality images without blurring due to flare light.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the internal structure of the exposure head according to this embodiment, FIG. 2 is a schematic diagram of an image recording apparatus to which the exposure head according to this embodiment is applied, and FIG. 3 is a separate body attached to the lens barrel. 4 is a sectional view showing the internal structure of a conventional exposure head, and FIG. 5 is an explanatory diagram showing the shape of one image recorded by the conventional exposure head. . DESCRIPTION OF SYMBOLS 10... Image recording device, 16... Photothermographic material, 28... Heat development transfer section, 32... Image receiving material, 34... Heating drum, 70... Lens barrel, 72... - Optical system, 80... LED chip, 84... Output port, 86... Rib. Figure 4 Figure 2 Figure 2

Claims (1)

[Claims] (1) An exposure head that records an image by condensing a light beam emitted from a light source by an optical system and forming an image of the light beam on a recording material, the exposure head comprising a lens barrel that holds the light source and the optical system; an exposure head, the light-shielding portion having an opening provided at an exit of the light ray of the lens barrel and having an opening smaller than an effective diameter of the optical system and having approximately the same diameter as the diameter of the bundle of light rays to be emitted.